Comparison and review of portable, handheld,
1-lead/channel ECG / EKG recorders
IMPORTANT WARNING -- READ THIS FIRST:
This website is provided for informational, educational purposes only, NOT medical advice.
In the event of heart problems or even the possibility of heart problems and as appropriate for your situation, go to the ER, call for help (such as 911), or contact your physician (or cardiologist, perhaps by referral). Do not attempt to self-diagnose or spend (further, if monitoring) time with self-help resources, including personal ECG devices, when urgent or emergency situations may be occurring.
If there is an emergency or suspected-emergency situation, appropriate medical help and facilities should be sought as quickly as possible. The only time that personal ECG recorders should be even considered in urgent, emergency situations, except as prescribed by a physician or when used by emergency personnel, would be if problems were to occur in remote locations to obtain useful information and/or while waiting for transportation and help, that is, when the use of the recorders would not delay possible help and might permit the collection of useful information for later use.
Self-diagnosis, even when there is no obvious or suspected emergency, is not advised under any circumstances without previous training and consultation, such as with a cardiologist or other medically-certified person with a specific background in ECG interpretation. (Note that many non-cardiologist physicians are not competent at ECG reading.)
Also please read additional disclaimers and related information further below.
CONTENTS [Not currently linked internally. You will need to scroll down to the various sections; some of the sections also have several subsections.]
Important top-of-page warning
Table of contents and notes on revisions and updates
Overview, including introductory photos, and a short primer to help narrow the choices -- including "tester's choices"
Webpage background and additional disclaimers and cautions
Introduction to ECG and ECG recording devices
General comments about the devices reviewed
Devices tested: descriptions, with photos and ECG outputs/reports
*** section under continuing construction -- stay tuned ***
AfibAlert -- company website -- a device specifically targeting the detection of atrial fibrillation
AliveCor / Kardia -- company website -- a family of advanced smartphone and tablet devices and apps, with interpretation services available
Cardio B Palm -- see PC-80B Color
Dimetek Micro Ambulatory ECG Recorder, DiCare-m1CP >
DiCare-m1CC (color) -- company website -- small devices with numerous modes and options
ECG80A / EKG-80A, ECG90A (printing, and full 12-lead) -- company website -- (ECG90A [and they have many other ECG devices as well])
ECG Check -- company website -- a basic, low-cost smartphone device and app which is undergoing further development
HeartCheck Pen -- company website -- a pocket or purse device with interpretation services available
InstantCheck -- company website -- an earlier but still excellent compact device with basic, user-friendly software
Kardia -- see AliveCor
MD100E -- company website -- the latest version of a device and software that has undergone much development and updating
PC-80 -- company website -- one of the earliest handheld ECG devices, still on the market but now largely supplanted by the latest version(s)
PC-80B Color -- company website -- a highly developed, flexible, and advanced device with many options and software choices,
Cardio B Palm is a version of PC-80B Color available in Europe and UK, do a browser search for: cardio b palm
Prince 180B -- similar to the PC-80B Color but with fewer features, in particular only does 30 second recordings
ReadMyHeart -- company website -- one of the earliest, basic handheld ECG devices, in compact form, and still available
REKA E100 -- company website -- a device for the general patient (who has little or no knowledge of ECG) with direct links to their personal physician
About the Author
Appendix: Disclosure/transparency re. potential conflicts of interests
Latest revision: September 26, 2016
Previous revisions: 2006-2008, 2013, 2014-2016 (numerous updates) ...
Original version: 2006
This is an independent and volunteer website provided to the internet community at large as part of the service mission of North Dakota State University. I update, revise, reorganize, and try to improve the site as I have time apart from my numerous other projects (both ECG-related and non-ECG), activities, travel, and a wide variety of other commitments.
Because of the rapid developments in technology and changes in the products and software (or apps) described here combined with numerous uncertainties and interruptions in my schedule and limited time to update this site, the information is outdated to some extent almost by definition. The dates of revision are posted both for the website as a whole and for particular ECG devices with their descriptions. The information is provided only as a starting point for education on the subject, decision making, and for what it's worth.
For the latest, most up-to-date information and developments, go to the various company websites through the provided links or additional web searches.
Website is currently undergoing (further) revisions and updating. Planned major changes and possible changes being considered:
- A possible summary table that shows which devices have which features
- Information on how to use devices (those for which it is possible) for long-term (hours) recordings and to obtain more leads/sequential 12-leads
- Internal webpage links to different sections and contents (and possibly making the Contents a side panel that can be accessed any time without scrolling)
- Links to other sources of related information(such as discussion groups, message boards, etc. among persons with afib and other arrhythmias);
I added some links, as a primer of sorts, to heart irregularities or arrhythmias such as afib etc. in the "Intro to ECG ..." section
Photos of the handheld ECG devices reported in this website
The photos have been sized to illustrate all devices to approximately the same scale (except open views of the two that flip open, shown with curved arrows, to save space). The three devices with green arrows pointing toward the right have undergone considerable development and updating, with the most recent shown to the right in the series.
OVERVIEW AND A SHORT PRIMER ON HOW TO NARROW THE CHOICES
There are so many handheld ECG devices now available that choosing which one to get can be daunting and not easy! To begin with, choosing a device depends partly on whether you are (1) a medical provider (physician, clinic, etc.) looking for a device to prescribe or send out with your patients or (2) a layperson with various understanding (from little or none to much) about the subject of ECG. If a layperson it will further depend on how much you already know, want to know and work with on your own, what heart conditions you might have (versus, say, having no heart conditions but simply wanting to monitor your heart, like checking your own blood pressure, perhaps in association with daily exercise), and to what extent you need or want to consult with a physician (cardiologist or otherwise). Then there are a host of other considerations including cost, whether processing and storage of records are done in the device alone or also on one's own computer and/or external servers (the "cloud"), whether you want/need only brief samples (e.g., 30 second) or perhaps the option of longer (minutes or hours) recordings, to what extent you might want/need analysis of results by someone else (your own physician or an ECG analysis service with ECG technologists and/or cardiologists, usually for a fee), and whether simple finger contacts will suffice for recording ECGs or if you want/need the option of using cable/lead-wires and adhesive skin electrodes.
IF you are a medical provider:
You will need to carefully consider your needs and look at the details on these pages carefully. I recommend that you go with one system so you don't have to juggle with variation and different learning curves, different software packages, different billing programs, etc., which are associated with different systems. Some of the devices reviewed on this webpage provide both event-type recording and Holter functions similar to event and Holter recorders of the past. Virtually all of the devices described here produce useful arrhythmia data (the primary purpose of 1-lead devices) but, since most patients and efficiency (including teaching patients how to use the devices) will require something simple, keep simplicity in mind (but in combination with something that will do the job for your needs). Perhaps start by considering the devices listed for the majority of laypersons in the next paragraph plus take a look at REKA, which was specifically designed for medical providers (although it might add a layer of cost aspects that could complicate your present payments system). Consider whether you want the option of using cable/lead-wires+skin_electrodes and Holter-type functions (all of which reduce ease-of-use and add to the complexity). Also note my comments in the "tester's choices" section below.
IF you are a layperson:
For the vast majority of layperson users of handheld ECG devices, in my experience with many friends, contacts, and colleagues, you will want/need the device for a given problem such as afib, be using it while under physician/cardiologist care, and only use/need it for a relatively short period of time (generally less than a year and often even less than a month) ... until the problem has been better identified and, hopefully, solved by an operation and/or medications. Your role as a patient doing home monitoring is to to simply obtain the recordings and pass them on to your physician, not to read and understand the results, but be able to properly record and either store or immediately send them to your physician. You may also need to learn, with help from your physician, how to recognize the difference between recordings that are not of concern (and don't need to be passed on to the physician) versus recordings of potential concern that your physician should see. For such users, the system should be simple and efficient for communication with the health care provider. Several of the devices reviewed here fall into that category and I suggest considering AfibAlert (specifically designed just for afib), AliveCor, ECG Check, and HeartCheck Pen. Also consider REKA, which is perhaps the simplest and easiest to use device, but it is (should be) obtained by the health care provider not the patient, unless you want to ask your health care provider to look into it for you (as in, "Ask you doctor if it's right for you").
The devices listed in the paragraph above probably provide the quickest communication with your physician. The next level of devices, which are still simple to operate but require the user to upload the data to their computer and then send the files to the physician, are: ReadMyHeart, InstantCheck, and PC-80 (original).
For most laypersons, once their arrhythmias have been identified and dealt with, unless a person has to live with and monitor the condition on an ongoing basis, they get back to normal living and have no further need, desire, or interest in an ECG device.
For persons wanting to get deeper into the subject and more long-term monitoring, with more extensive interests, or doing research on their own, including doctors/academics/engineers/other professionals who have their own heart problems and already have a background or are willing to learn the details about ECG, and those who want devices for monitoring excercising, etc., or researchers, and all of whom might want options such as longer recording sessions and cable/lead-wires with adhesive skin electrodes, consider: PC-80B Color, Dimetek DiCare-m1CC (color version, not m1CP, the older version), InstantCheck, MD100E, or the printing device ECG-80A (or one of the newer versions). Between the PC-80B Color and Dimetek DiCare-m1CC, both do good recordings, have the option of using lead-wires, will record for long periods in Holter mode, and have good color displays. The m1CC is smaller, lighter, takes up little space and is unobtrusive when worn as a Holter, plus it has a more accurate internal clock over long periods of time (weeks to months), but it is more subject to movement artifacts and the software does not have as many functions as the PC-80B Color. The InstantCheck is a great, updated, solid, and long-popular system but costs slightly more than the others. The MD100E is good but unless and until the software issues are solved, the software can be a hassle to work with. The printing devices are in their own category, see the details in their expanded description below.
(added 9/25/2016, subject to change pending revisions in the other devices and possible new devices that appear and get tested)
For several years in an attempt to stay neutral, as objective as possible, and not express my personal choices, I mostly avoided stating my opinions and making any recommendations on this website. However, in response to numerous emails that I received asking for help in deciding what was best for particular situations and in view of significant revisions in devices and software that some of the companies have made, which clearly improved them over both their own previous versions and the current versions of competitors, it became necessary (and yet still objective) that I state my personal choices. The three on this current list are the ones that I myself use routinely. At the same time, I also need to say that even though the various other devices shown on this webpage are not "tester's choices", they are still good, all passed my criteria for getting listed on this webpage, some might be better for some persons for various reasons, and all of the others on this website (plus perhaps others that I haven't tested) are also worthy of consideration.
The three current tester's choices are: AliveCor / Kardia, PC-80B Color (not previous versions and not Prince 180B), and Dimetek DiCare-m1CC (not the m1CP, differing in name by only the last letter).
The main, general reasons for choosing these three are that they all have resulted from significant revisions, developments, and major improvements in either or both the devices themselves and their associated software packages.
For specific details and who each one is most appropriate for:
- AliveCor / Kardia has made numerous, impressive, ongoing, and well-tested revisions plus added several options, functions, and features while, at the same time, remaining low-priced. This system is primarily for the general public and/or persons who want a quick ECG sample of a one-channel recording at any particular time using simple finger contacts. It is simple, fast, direct, accurate, and the smartphone app (for both android and iOS) is loaded with options and features. New developments are continuing as we speak. AliveCor has a large, active team with much knowledge and experience, including previous work and experience in the medical field and at least one of the major ECG companies. For more information and to purchase, click here.
- PC-80B Color is the result of several revisions (and diversification, presently available in both cabled and bluetooth wireless [at higher cost] versions). It has excellent and very intuitive, user-friendly software with several functions and options including the ability to see a summary of the entire recording or at various levels down to individual ECG waveforms. It has both simple metal skin contacts for quick recordings and cable/lead-wires for use with adhesive skin electrodes and longer recordings up to 10 hr max (per recording ... which can be uploaded and saved to a computer and then another recording can be run). It can be worn as a Holter, including during exercise and daily activities (including at night while sleeping). It has a lighted display so it can be used and viewed easily in the dark. It has three lead-wires (positive/+, negative/-, and neutral/0) which gives more stability to the signal but also adds an additional electrode to the skin compared to the next device listed below. The PC-80B Color is the device that I myself use most often and I recommend it highly. It is FDA approved. Caution: It has a sibling, the Prince 180B, which is not as functional (only does 30 sec recordings, at least in the one I tested ... I've seen a few advertisements for ones that purportedly do the longer recordings but I don't know if what they are listing is false advertising or yet [sigh!] another version with name confusion). To be safe, make sure you get the device that is clearly labeled PC-80B with the color screen display; see detailed description further below on this website. The PC-80B Color is best used by (or under the direction of) medical personnel or persons with (or willing to learn) more knowledge of ECG than most laypersons. It is available from several sources, including many listings on eBay, from both Chinese and US marketers, at a remarkably low cost (depending on who you buy it from). To find a source, do a general browser or eBay search for it.
- Dimetek DiCare-m1CC (not the m1CP which is the older version) is the second, greatly improved version of the dimetek device and it's latest, revised software. It has slightly fewer software functions than the PC-80B Color but has the added function of displaying Poincaré plots for persons interested in HRV/RRV and it's waveform displays are excellent, useful, and easily scrolled through for long recordings. It has both simple metal skin contacts for quick recordings and the option of cable/lead-wires for adhesive skin electrodes and longer recordings. There are only two lead wires (+ and -) which has the advantage of only two electrodes (quicker to apply and lower cost etc) but slight disadvantage of being more vulnerable to artifact -- but still providing adequate recordings even during activity including exercise. It has built-in capacity for much longer recordings and more memory for many recordings than the PC-80B Color. It's main advantage over the PC-80B Color is smaller size which makes it easier to wear conveniently and unobtrusively such as out and about in public during daily life and is slightly less cumbersome when worn at night during sleep. It has lighted display so can be seen in the dark. As with the PC-80B Color, it is best used by (or under the direction of) medical personnel or persons with (or willing to learn) more knowledge of ECG than most laypersons. The DiCare-m1CC is still in the FDA approval process (which takes a long time) and not yet available in the US, although it can be imported from the Chinese distributor. I'm not yet certain what the cost will eventually be (I received mine as a test product), but it might be higher than for the PC-80B Color. For further information until I can get more added to this website, click here.
There are trade-offs between the PC-80B Color and DiCare-m1CC, with each having particular advantages over the other as described above. Because I myself do a lot of ECG work and recording, I have both and use whichever one is best suited for a particular application.
Note regarding apps and software:
In addition to storing and viewing ECG records on (some of) the handheld devices themselves, there are two methods of uploading, analyzing, viewing, storing, and otherwise working with the ECG recordings: cloud-based (that is, on an external server somewhere else, beyond the user) or user-operated software programs, on the user's own computer. There may also be hard-copy printouts or electronic (e.g., in pdf format) that are portable and may be in the cloud and/or on a user's own computer or various storage devices.
The cloud-based ECG devices, with apps designed for Apple iPhone/iPad/ and Android smart phones, plus uploadable via various computers, netbooks, etc., are: AfibAlert, AliveCor, ECG Check, HeartCheck Pen. and REKA. (Of these five devices, incidentally, all use metal skin contacts and do short recordings of less than a minute. Only REKA, pending developments by the other four, also has the options for using cable/lead-wires with adhesive skin electrodes and for recordings longer than one minute at a time.)
All of the others require user-operated software programs (provided by or available from the companies distributing the devices, usually as a part of the device packages) that work only (to the best of my knowledge) on Windows-based (or perhaps related PC, e.g., Linux?) platforms, not Macintosh. (Various of these others include options of either metal skin contactsor cable/lead-wire/adhesive-skin contacts and short versus longer, Holter type, recording durations. See descriptions for each device.)
Webpage background and additional disclaimers and cautions
Intended audience --
This information is intended for the general public, physicians, medical centers, and other health-care providers such as EMT personnel and nurses, instructors and students (pre-med, other health-related, general), electrical and biomed engineers and designers, and manufacturers and distributors. In addition, this information and the comparisons may be of interest to investors because the industry is expected to grow rapidly (and be highly competitive) in the next few years. In short, this webpage has been prepared for anyone who might have an interest in handheld ECG devices. Most, but not all, of these are currently 1-lead/channel, but I have included one 12-channel device (the printing one, ECG/EKG-80A), some of the others can be used to obtain good (sequential) 12-lead recordings, and I anticipate new, handheld, 12-lead (even simultaneous) ECG devices coming on the horizon.
As indicated in the warning section above, the information in this website is provided for informational/educational purposes only. For medical and health-care providers, see the next paragraph. For untrained persons, the devices are potentially useful for exercise- or sports-associated (by healthy persons), research, educational, and non-emergency monitoring use only, not diagnostic or emergency uses.
For health-care professionals, however, the information here may be useful for evaluation and consideration of potential 1-lead/channel products (similar to familiar cardiac event and Holter recorders) for monitoring of and by patients including post-surgery, monitoring for arrhythmias such as afib, PVCs, PACs, ventricular tachycardia or bradycardia, and related monitoring and recording.
A changing and highly-competitive field --
At least for the foreseeable future, this website is expected to undergo occasional revision and be subjected to further reconstruction. Technology continues to change; products and software are being revised; new products appear; and pending my available time and with accumulated experience, testing of recorders, exposure to new products and software, and input from other persons, I may add, delete, and revise sections as well as reorganize this site. It is also an expanding webpage and continuing to grow. Until internal links are added, you can simply scroll past sections that you aren't interested in to find sections and information that you might want. Thank you for your patience with the site's current condition. Check back later for updates, possibly additional ECG recorders, and other revisions.
Criteria for inclusion of ECG devices on this webpage --
ALL of the ECG devices described and covered in this review are ones that I consider acceptable for their respective uses. They each fill a slightly different niche, as described with the various devices. It is completely up to the potential users to make informed decisions about which is best for their particular needs. It's like buying a vehicle: there are several brands and models available. Different persons are interested in different ones for different reasons.
The only ECG devices listed here are those that Ive had sufficient time to evaluate and which I considered worth listing. There are many more available in the market. There have been a number of new handheld ECG systems and various revisions that I tested but which weren't very good in my opinion or worth updating this website for. Thus, I have not included them here. Others I am still testing, including in some cases working with the designers/manufacturers to improve. There are several others that I simply have not had the time, inclination, or other resources to test. There are more out there, and more appearing every day, than I am able to test and report on, sorry (both to the companies and the readers).
My principle is If you like what you see, tell others. If not, tell me. Thus, I will publicly describe products that I have tried and which sufficiently meet my personal criteria. I also will gladly (pending my time and availability) test and help designers and manufacturers improve their products by reporting my detailed test results and problems that I encounter back to them for their in-house, proprietary purposes and revisions (and I treat those proprietary interactions with each company or distributor on a non-disclosure basis, whether formal or implicit). I have done that with several companies and the public results shown here generally reflect their latest, revised versions and models. In my opinion, that is advantageous to everyone: users and public health-care, physicians, and the industry as a whole. (The principle, incidentally, works both ways. If you like this webpage, tell others. If you find any errors, large or small, have problems with anything here, or want to provide various suggestions or other input, please send your comments and any corrections to me so I can revise the webpage. Thank you.)
Although I provide my tester's choices and make recommendations for different users/situations as descrived elsewhere on this website, I do not endorse any given product. Like Consumer Reports, I do not want my statements to be used by anyone for advertising purposes. The exception is that anyone, including distributors and manufacturers, may freely link to or reference this website as long as they do not expand on it or use my specific statements as an endorsement (implied or otherwise) for their product. I maintain my right to objectivity, academic and professional integrity and freedom, lack of influence and bias from vested interests, and, at the same time, my right to work with any and various companies and distributors. I have tried to emphasize the facts and minimize personal opinions beyond what I consider to be my acceptable criteria and recommendations for particular users/situations. Some of the features of some of the devices are truly impressive, however, and I maintain my right to express personal opinions and choices on those points.
Sections About the Author and Disclosure/transparency regarding potential conflicts of interest are included at the end of this website.
Introduction to ECG and ECG recording devices
ECG/EKG basics (ECG or EKG -- the two are synonymous, just different spelling) --
Do a web search for more information about the heart itself and the general subjects of ECG/EKG (recorded heart signals, electrocardiogram or various European spellings [such as the German elektrokardiogramm], derived from the Greek "Kardia" for heart), also electrocardiography, electrocardiographs (the machines that do the recordings). There are particularly good resources by doing searches at Wikipedia, American Heart Association, Mayo Clinic, and many other sites that you can get from google or other browser searching.
ECGs and their different "leads" are complex and have a fairly steep learning curve. IF you want to go into more depth for understanding ECGs and are looking for primers or places to get started:
For a webpage that I wrote for our university students and others to introduce the general subject of ECG
(focused on standard 12-lead systems), click here.
Other good general webpage introductions to ECG are available here and here.
If you want more details and series of online lessons on ECG see ECG Academy, EKG Academy (different from the first one),
and/or (another academy) Khan Academy ECG videos.
Arrhythmias or irregular heart beats (as opposed to other problems like heart attacks) are the primary targets of 1-lead devices.
Here are some examples of what they look like on single leads: ... click on the names. (Reminder: consult with your physician and
learn what particular condition[s] you have or might have. Do NOT self-diagnose! Monitoring after consultation with a physician is
different than self-diagnosing.)
(Note that each example illustrated below includes a built-in caliper [blue lines] that you can grab and move to measure times.)
Normal ("normal sinus rhythm" or NSR, from the heart's normal pacemaker) as an example to compare the abnormal rhythm ones with.
Atrial fibrillation (afib or AF), one of the most common arrhythmias of concern.
Atrial flutter (aflutter), as with afib and often of concern.
Premature ventricular contraction/complex (PVC) very common and easy to identify, obvious, but usually not of concern.
Premature atrial contraction/complex (PAC), also common but more difficult to see than PVCs, also usually not of concern.
And there are (many!) more, but not as common, arrhythmias. For a more complete list, if interested, click here.
And, of course, there is a ton more on the internet and in books (e.g., click here).
ECG machines/recorders/devices are no longer just the large, bulky equipment that they once were. Even some of the full 12-lead recorders today are small, portable, and operate through desktop and laptop computers or other devices.
Now there are even smaller, self-contained, simple, one lead (or "channel") recorders that are handheld, pocket-sized, battery operated, and have their own built-in displays. These new, low-priced, 1-lead handheld ECG recorders have become available for physicians to prescribe for patients and some over-the-counter (OTC) for personal, home, and exercise or sports use, much as with home blood-pressure/pulse recorders or glucose testers for diabetics (but see below for qualifications and complications).
Note that this technology and availability of personal ECG recorders are new and just now entering the consciousness of mainstream health care. Many physicians and cardiologists themselves are not yet familiar with these devices!
They are potentially suitable in some emergency situations but only by order of a physician and when used by medical or emergency personnel or for obtaining useful information while waiting for emergency help to arrive. Otherwise, they can be used by the general public (generally in consultation with and approval by a physician) for non-emergency personal recording of information, such as for baseline information, routine monitoring, or during uncommon cardiac events. The recordings can then be shown to the person's cardiologist or electrophysiologist or, for non-emergency or simple monitoring purposes, used by the person himself or herself if he or she is able to interpret them. (See the subsection above for links to learning more about reading ECGs, if interested.)
ECG machines record the faint electrical signals produced by the heart and which spread throughout the body all the way to the skin. The ECG machine or device picks up the signals by contact with the skin through interfaces called electrodes (the name of the contact surface). The process is non-invasive, harmless, and risk-free. ECG machines are carefully designed to separate any electricity used to power the machine from the heart signal detection and recording process so the machine is unable to accidentally shock the persons involved, thus, insuring their safety.
The resulting records of the heart signals, the wavy lines called ECG waveforms or patterns, are generally familiar to everyone. The pattern is seen on monitors in hospitals and clinics, stylized on the sides of ambulances and in advertising, seen on TV and in movies, etc.
The "devil is in the details" --
The actual details of the pattern, however, are very complex and require a trained and experienced human eye, normally of a licensed physician or certified ECG technologist, to interpret, understand and diagnose the recorded ECG, and then a licensed physician to recommend or prescribe medications and courses of action, including possible referral to further medical specialists.
Unlike many other health and physical characteristics, such as blood pressure, simple pulse rate, or blood glucose levels, ECGs do not have just one or a few numbers to work with. Even the heart rate may include irregularities and changes in the rhythm and shape (morphology) of the ECG waves. ECGs involve subtle aspects, characteristics that are relatively unique to each individual person (somewhat like fingerprints), complicated combinations of characteristics, and often, on their own, don't give a complete picture of what the heart is doing. ECGs provide very good measures of the hearts condition but an ECG is only one set of measures. Additional tests may be needed for an accurate diagnosis of a persons heart.
Automated measurements and interpretations of ECG patterns by the ECG machines or computers (including by the best available) notoriously make mistakes including both false positives (identifying conditions that are not actually present) and false negatives (not detecting conditions which are present). Examples are shown on this webpage under the MD100E description (but errors in automated readings are universal, not restricted to just the MD100E).
... and things get tricky!
As a result of the difficulties described above, particularly when there may be medical conditions or issues (and potentially legal issues), a real, live physician must be involved at some point. Accordingly, ECG machines are classified as medical devices and, in the US, the government regulating agency, the FDA, requires clearance or approval (not the same, but I'm not going into that) of them before they can be sold in the US. The FDA also requires that the machine and associated materials be properly labeled with appropriate warning and caution statements, and, unless cleared for over the counter (OTC) restricts their sale to physicians or on the order of a physician. The regulations have not been strictly enforced at the level of actual sales and purchases, but manufacturers and distributors of ECG machines must pay close attention, get FDA approval for new products, and use proper labeling. All of this helps protect the public, physicians, and industry, including the industry from legal liability. At the same time, regulations are having difficulty keeping up with the rapidly changing technology and global marketplace. A number of grey areas, potential risks, and questions are arising such as just what is the role of the physician and related FDA matters (example, including be sure to scroll down to the subsequent comments section which contains much discussion on numerous issues).
... but there is hope!
Although the heart conditions people can have and their associated ECG patterns cover a vast range of possibilities, in any given person, if not normal, there is usually has just one or at most a few conditions present. A physician can teach the person what their ECG pattern(s) look like and what to watch for. Or, once a person's condition has been properly diagnosed and been (or is being) dealt with by a physician, a person can learn more about their condition through additional resources such as the internet. Thus, while persons who are not physicians should not try to diagnose their own or others' ECGs, they can nonetheless learn what to watch for and monitor themselves for changes that are specific to their cardiac health status. This, along with rapid advances in technology and a recent general increase in the public's interest and participation in management of their own health care, has led to the introduction of low cost, relatively simple and small, handheld, portable ECG devices. There are now many readily available and more on the horizon. This website discusses some of them.
Who cares about ECGs, how much, and why?
Just as different ECG machines vary, so do the needs and interests of different persons. Most healthy persons have little interest in ECGs, theirs or anyone elses. Most normal heartbeats are the same, beat after beat, for millions of beats. Although they might vary slightly for an individual and from person to person, "when you've seen one you've seen 'em all".
But, with the heart as central and critical to life as it is, if something goes wrong or there is even a hint that something might be wrong, most people begin to take notice and may become interested in whats going on! However, the majority of persons still aren't interested or able to deal with the detailed intricacy of ECG interpretation; they want their physician to handle all of the details. Thus, they or their physician may want a personal monitor for the patient that the patient can operate but everything is then handled by the physician and they simply communicate (via modern technology) with each other.
At the other extreme, there are persons who, while still being involved with a physician with their heart conditions via normal, typical health care hospital and clinical routes, also want to monitor their conditions themselves. In addition, there are many persons with normal healthy hearts, including athletes, persons who are active and do serious workouts or exercising, pre-med and other health-care students, instructors, or others interested in cardiovascular topics, and people who travel to remote areas who want to have equipment for educational purposes or monitor their hearts on their own, pretty much independently, like weighing themselves or monitoring their own blood pressure and heart rate.
In between the two extremes, there are many people who want to maintain very close association with and supervision by their physicians but who want to do their own recording and then take the results to their doctors. The variety of ECG devices now available covers the whole range! I have attempted to show where each of the devices that I reviewed fits into the picture.
Note: more devices available than just handheld ECG devices ...
There are also a number of other ECG-like devices, heart monitors, and pulse oximeters including finger, wrist, and wrist-chest devices, that only show heart rate or pulse rate (pulse rate is not always the same as heart rate because some irregular heart beats produce electrical signals but do not register on the pulse). Some of these devices produce long-term records, storage, and computer or cloud-based options for viewing and analyzing results. If you know what to look for, they can also identify or help identify such things as irregular heart patterns, such as afib. I have tested several of them (and associated software and apps, including for heart rate variability [HRV/RRV]) extensively but am not including those results here; perhaps another day.
General comments about the devices reviewed
Categories or types of devices: prescription versus over the counter, server- or "cloud-based" versus stand-alone
Some of the handheld ECG devices and their software or apps are physician- or central-server/analysis-, "cloud"-based ECG systems in which the users interact with their health care providers by using small, portable, ECG recorders designed specifically for working over the internet and/or smart phones, in most cases via various apps. Their data are sent to a physician or central site for analysis, with results reported back to the patient or user. There may be per-use charges for some of these devices.
These may prove to be a great choice for both the majority of patients/users and physicians, as alternatives to previous, old-style "event recorders" and even some Holter applications.
However, a few users want to view the results on their own computers and under their own control, even if they also pass the results on to their physicians, and who may not like the need to go through the "cloud". Thus, there are also completely stand-alone, non-cloud choices.
Some of the ECG recorders are available for over-the-counter (OTC) purchase, and anyone can get one, use it themselves (including with the associated interpretation services that are also available from some companies when desired or needed), and/or communicate the results with their physicians. Although some of the devices are OTC and show basic results of recordings, such as heart rate and a simple statement or icon regarding the outcome, they still require initial contact with a physician, either via a provided interpretation service or the user's own doctor, before the full functionality of the device is enabled. I anticipate that some of these OTC ECG devices will begin appearing in pharmacies and chain stores.
The ones (of all types) that I have tested are shown below with brief descriptions and links. I plan to eventually provide expanded descriptions, photos, results of my testing, and more details here. In the meantime, most have lots of descriptive information available in their various links.
Dry metal, finger/thumb/skin contacts versus adhesive skin electrodes and cable/lead-wire connections
Most of the handheld devices have simple metal contacts that the user can place their thumbs or other fingers on or place against bare skin, such as on the chest. The metal contacts are much more convenient and faster to use than adhesive (or older, electrode cream style) skin electrodes. Some of the devices, not all, also can be used with optional adhesive skin electrodes (usually of the "snap" variety) and cable/lead-wire connections. Some use three lead wires (negative, positive, and ground/neutral) whereas some use just two (negative, positive). (The negative electrode is normally used with the right hand or side of the body and the positive on the left. They usually are just labeled "L" and "R". Colors vary among the different devices and their color schemes).
Examples of the metal skin contacts versus lead wires are shown in the figure below (from the original three devices reviewed on this website, 2006-2008). All three of these recorders will operate with dry-contact skin contacts, for example, with the subject's thumbs placed on the metal contacts.
Recordings in general (but not always!) are much cleaner, consistent, and more accurate if adhesive electrodes are used rather than the dry skin contacts that are built into the machines. The thumb/skin contacts are definitely more convenient, quicker, and produce good results with practice. But they also usually produce more variability and artifacts than one wants. Here are examples of comparable records with the thumb contacts held in a typical fashion; thumb contacts held with deliberate care in a gentle, steady, careful, and practiced manner; and with adhesive electrodes. There are more artifact noise and artifacts called baseline wander in the typical thumb contact example. (Original figure from excerpts of RMH results.)
Comparisons of outputs among the various devices and against standard 12-lead outputs
(see "Intro to ECG ..." at the top of this webpage if you need more information on 12-lead ECGs)
I considered attempting to show outputs from the devices in a side-by-side or overlaid manner, next to each other and in comparison with standard 12-lead outputs for similar records. However, there are too many possible comparisons, too many permutations, and it would be unwieldy to make such comparisons here. Thus, I will let you, the reader, decide what you want to compare and then scroll back and forth through the various device descriptions (and the 12-leads, if you want) for comparisons.
In my description of each device I have included figures of their device-screen displays, computer-screen displays for uploaded records, and views of their hard-copy printouts.
Note: Outputs of ECG records commonly start with a period of instability (wandering baseline and artifacts) for a few seconds but then typically stabilize. Ignore those initial unstable periods when they show up on the outputs. Most persons recording ECGs and some ECG equipment and devices don't start recording until after the signal has stabilized.
Example of a computer screen view (top figure) and printout (bottom figure), for comparison, from a PC-based standard 12-lead system. This recording, incidentally, is from an older (but still similar to current) recording from myself (as the subject also for these handheld devices) with a normal heart rhythm ("normal sinus rhythm" or NSR).
This example is from one of MANY brands and models of PC-based and stand-alone ECG machines. There are many more. They each have their own various ways of displaying the heart pattern waveforms and results (recording information such as date and subject, automated measurements and interpretations, etc.) but most of them also use more-or-less standard formats for presenting the different leads, such as 4 columns x 3 rows for the 12 leads plus one or more rhythm rows at the bottom, or 2 columns x 6 rows, etc (there are additional standard formats).
How to use these units in 12-lead and exercise contexts
It is possible to obtain additional lead information, in sequential manner, with some of these devices. (Not all of them work well for additional leads.) In some cases, one can obtain all 12-leads, which are often very comparable to what would be recorded with standard 12-lead systems. Most of the devices can also be used in exercise or what I refer to as "pseudo-stress test" situations. For further information and suggestions (along with the appropriate disclaimers), click here.
Sources for 1-lead handheld ECG recorders: See the listed link(s) at the end of each description or do a browser search for the names of the devices. Many of them are readily available online from the companies themselves, several medical device suppliers, dedicated distributors, sometimes on eBay, and perhaps on other sites such as Amazon.com. For a good source of some of them, also see Favoriteplus.com, the source from which I have gotten some of the units for testing (see Appendix re disclosures/transparency).
General note regarding ECG device user manuals and software from Chinese manufacturers and distributers
Many, if not most, current handheld ECG devices and software packages are made in, and often distributed from, China. The English of Chinese ECG device manufacturers and distributors is much better than my Chinese (which is zero!) and I have to give them credit. And some of the manuals and software programs for ECG devices from China have been written by persons in China with good English or originally written or subsequently edited and rewritten by other native English-speaking persons outside of China, so the writing is excellent. In many cases, however, the documents and software were written or translated into English by someone for whom English is a foreign language, or perhaps translated by computer software programs, and things are often lost or mangled in translation, grammatical and spelling errors are common, and phrases or terms (including medical) frequently don't make sense to a native English language user (including medical or other persons who are used to standard English ECG terminology). One person referred to the Chinese-accented English writing as "Chinglish". Most native English readers find it at best distracting, the meanings often difficult to understand, and sometimes just amusing or even wrong. I haven't bothered to point out which devices' manuals and software programs suffer from these problems, but will issue a general caution that native English language users should not be surprised when such problems are encountered, including difficulties trying to follow installation and operation instructions. (On the other hand, I find that many of the Chinese software programs install faster and with fewer hassles than American software!) You will have to do your best to live with language glitches when encountered, try to appreciate our language differences, and hope that future editions will be corrected by someone with a better command of English.
DEVICES TESTED(in alphabetical order)
UPDATES: device added to webpage 8/26/2014
Atrial fibrillation, afib, or AF, is one of the most common heart irregularities or arrhythmias. I have it myself occasionally to frequently. It is one of the conditions that got me deeper into the subject of ECG.
The AfibAlert is a handheld ECG device designed specifically for atrial fibrillation. It is not intended for diagnosing afib per se, only a physician can do that. Instead, the AfibAlert is for monitoring the condition on an ongoing basis and identifying any sustained episodes of it. That is, when you have already been diagnosed with afib and know that you are susceptible to it, AfibAlert allows you to check for afib at any time, whether you are just doing routine checks for it or sense that you might be having it when feeling palpitations, a racing heart, or other symptoms such as light-headedness.
AfibAlert is very easy to use and works for anyone at any level of knowledge about ECG, whether you know or care nothing about the intricacies of reading ECGs, know a little or a lot about it, or are a cardiologist or other physician who has patients with it or perhaps even have afib yourself.
To use it, you merely pick it up, use the built-in thumb contacts or electrode cable/wires (two wires plus unique wrist bands [described further below] or adhesive skin electrodes), push the start button, wait 45 seconds for the recording to run (while a little clock icon lights up blue and heart rate is displayed), then get instant results :
- green light / checkmark icon that afib is probably not occurring
- red light / phone icon that afib likely is happening (and you should perhaps call your doctor)
- yellow light / repeat icon that it was a poor quality recording and needs to be run again.
With the (patented) instant feedback feature, you dont need to send your ECG anywhere or pay to have your ECG reviewed as the AfibAlert has a built in algorithm that analyzes it for afib with a high degree of accuracy. When tested against 51,000 records, AfibAlert was correct about 95% of the time, which is a very high success rate (and probably much higher than with many non-cardiologist physicians!).
Following one or more recordings, you can use an app on your computer (Win XP, Win 7 & Win 8) to upload your ECG strips for viewing or sending to your physician. Once uploaded, you or your physician may view your ECG strips via mobile apps for both IOS and Android devices or on your computer at no charge.
You can contact your physician when necessary. Your prescribing physician also gets an account and can view your ECG strips as needed. The system is secure and password protected.
If you understand ECGs yourself, as a physician or otherwise knowledgeable about the subject, and want more than just the simple lighted icon results, you can view the actual ECG traces in the uploaded records and also print them out via pdf printouts that the system creates.
Although the system and its lighted icons are designed for atrial fibrillation, the recordings can also be used for normal rhythms and other arrhythmias as well as running additional leads with the cables/lead-wires and adhesive skin electrodes. It also can be used for looking at the effects of exercise and other aspects that persons who know what they are doing can do. I tested the AfibAlert under a variety of conditions, including exercise and additional leads, and got excellent results. Im not including the details for the additional tests on this webpage at this time but may do so if and when I have time in the future (for AfibAlert as well as for the other devices that are potentially capable of additional uses, that is, those that have the option of using lead wires and adhesive skin electrodes).
If one does not get good recordings from the thumb contacts (although this is not likely because the AfibAlert uses silver chloride electrodes in the thumb pad leads that provide excellent conductivity for recording ECGs), the AfibAlert system includes a unique set of wrist bands, like metal watch bands, that can be put on the arms and connected to the cable and lead-wires instead of using adhesive skin electrodes. That eliminates the irritation and rash that adhesive electrodes commonly cause to skin and also the need to have a supply of adhesive electrodes on hand. The photos further below show the wrist bands.
AfibAlert is an established system (first produced and marketed in 2007) and, unlike most of the other devices, made in the USA. All documentation is written in native English. It also has been FDA Cleared.
Depending on your needs and planned uses, the only potential drawbacks of the AfibAlert in its current configuration are lack of a waveform display screen and size. Again, life is full of tradeoffs and what one person desires might be undesirable for another.
Not having a waveform display screen simplifies the device, which is highly desirable and less distracting for the most common, general patient user. For persons who want to see the waveforms but dont need them in real time, you can see them in the uploaded records.
Size of the device is the other tradeoff. The AfibAlert is the largest of the handheld devices and may not be portable enough for some persons to carry at all times. However, it is in the same size range as many of the other devices and still small enough that it does not take up much space. It can be easily kept in a desk drawer, cabinet, nightstand or bedroom dresser, or on a shelf, table, or counter top, carried in a briefcase, backpack, purse, and possibly pants pocket for some, or whatever, or otherwise moved about to different places as needed.
The size and shape are good because they facilitate good readings by most people by fitting the hands comfortably and keeping the fingers of the two hands separated. When the fingers of the two hands overlap and touch, as easily happens with many of the other handheld devices, that could potentially "short circuit" the signals and effect the results, although I have never bothered to actually test for such effects. Also by having sufficient spacing between the thumb pads, the AfibAlert can also be pressed directly against your bare skin on your chest for a good reading as well.
I myself, and I suspect most users of handheld ECG devices, do not carry the devices at all times on a routine basis. What is usually important is that the device is accessible when and where you need it most frequently, such as for periodic daily checks two or three times a day or for when afib episodes crop up unexpectedly, commonly at night when at home or in bed.
For further general information about AfibAlert, I highly recommend their website, http://www.afibalert.com/, which is very well written, concise, and informative.
My tests and samples of my experiences with the AfibAlert are shown below.
I used the AfibAlert on several occasions when I was having afib and it showed all of them as afib. Thus, although it was a small sample size I got no false negatives (failing to detect afib). My afib produces average heart rates over 100 bpm, so I dont know what would happen with afib producing heart rates below 100 bpm or even below the lower normal range of 60 bpm; it should still show up as afib. I deliberately ran my heart rate up over a hundred with exercise, without afib, and got mixed results: some correct results and some false positives (saying there was afib when there wasnt). A lot of artifact also caused some false positives. However, (1) virtually all ECG machines and devices make some errors, as Ive explained elsewhere on this webpage; (2) AfibAlert comes with clear and proper warnings to that effect; (3) I was testing the system beyond its normal intended use (and recommendations that patients/users remain still while doing recordings); and (4) false positives are better than false negatives -- better to be safe than sorry!
I also frequently get premature ventricular contractions/complexes (PVCs). Those are not afib and AfibAlert ignored them. I didnt have any cases where runs with PVCs but otherwise normal and in normal resting range were identified as afib.
I also tested the device using a commercial, artificial ECG simulator (Symbio CS1201) under a variety of heart conditions including NSR, afib, atrial flutter, VT, and MI. I got mixed results with no false negatives but a few false positives (see discussion two paragraphs above, including the 4 points at the end of the paragraph).
Printouts of records, rather than showing heart rate (HR), show "Beats Counted". The heart rates shown on the device display screen during recording seem to be correct, after initially homing in on the average rate. According to the company when I contacted them, the "beats counted" reflects the beats used for analysis once the ECG recording has stabilized and not the total number of beats on printouts. They do this to increase the accuracy for analyzing the ECG. However they acknowledged that this information isnt very useful to the user and plan to modify it, likely replacing it with average heart rate in the next software release.
Photo of materials received with AfibAlert: Instruction Manual, Software Installation Guide (software available online, Windows PC only but with Apps for smart phones and tablets), carrying case, the AfibAlert ECG recording device, electrode bands, USB cable, and cable/lead wires.
AfibAlert device, electrode bands, and cable/lead wires.
Device with lead wires attached. I used a pen to mark the connectors as to which side of body and neg. vs. pos., for my own convenience. (The manual gives instructions as to which is which, but I work with a lot of different devices and they dont all use the same color scheme, so its easy for me to accidentally get them backwards. Many of the devices come with the connectors already marked, beyond color.)
As above, but connected to the electrode wrist bands.
Close-up of device while recording using the thumb contacts. The heart rate is displayed along with the blue-lighted clock icon which indicates that recording is occurring.
When recording is completed, the device analyzes the data and, when there is no afib, as in this case, the OK icon lights up green.
Recording while using the cable/lead wires, an example of recording during a bout of afib, with HR = 150 bpm.
After recording and analysis of a bout of afib, the red phone (call doctor) icon lights up.
When you click the AfibAlert icon installed on your computer or a smart phone, you get a login page, as shown here.
Computer screen view after logging in. For the "Type", "Green" means "probably not afib" and "Red" = "high probability of afib". Note ID 34086, which Ill use as an example below.
Example of the top section of the computer screen view of a record, in this case (34086) a normal sinus rhythm, not afib, and "Green".
Example above continued, bottom section of computer screen view. In this case, no comments have been entered yet. There is a box for entering and submitting comments.
Printout of case 34086. Printouts are accomplished by a built-in pdf creator in the system. The pdfs can be viewed on-screen, printed out, or archived (including as an electronic medical record or EMR).
See the note above regarding the "Beats Counted" at the top right of the page. The full count of beats for the 45 second recording, as counted on the printout, amounts to 68. For a 45 second record, that = ~91 bpm. Using the "big box" (5 mm grid) method of determining HR, if one knows how to do that (I wont explain it here), it is easy to see that the HR is under 100.
Back to the page listing records, and moving through the list a bit, note that these have not been reviewed (by a physician) but comments have been added to the records shown here.
When the AfibAlert device is connected to the computer, it shows the number of new recordings needing to be uploaded. Uploading is accomplished by pressing the "Synchronize Device" button and getting the pop-up screen shown here.
Example of a printout of an afib record, run via the thumb contacts, with comments that I added, showing at top of printout page 2 (the remainder of the second page is blank, not included here). This is a good example of afib, correctly identified by AfibAlert as afib (red), plus three PVCs which AfibAlert ignores.
The comments, shown above, are currently called "Public", which they normally are not or should not be (except here where I am posting the tests for the whole world to see). Rather, they should be considered as "Patient" comments. The company intends to address this issue with the next software release.
Another good example of afib, which AfibAlert correctly identified as afib, plus some more of my PVCs.
An example of one of my "clean" records, with a normal sinus rhythm, no afib, and no PVCs or other irregularities, and little artifact. Its always nice to get this kind of result!
- Physical: 5 7/8 x 2 1/2 x 7/8 in (150 x 70 x 22 mm), 4.6 oz (130 g)
- Display screen: indicates heart rate, plus color-lighted icons for results
- Length(s) of recordings: 45 sec
- Time to auto-shutdown: (Always "on-standby" and ready to record immediately when the power button is pressed; then back to "off" until the next recording.)
- Additional cable-wires for adhesive skin electrode recording: yes, a 2-wire system
- Internal or memory-card storage capacity: 30 records then new ones replace the oldest recordings; memory can also be erased
- Ability to add comments to recording files: yes
- Device menus and ease of use: (easiest possible, just push button and record)
- Software or app menus and ease of use: uploading is easily done through the computer or app; menus for viewing records are clear/intuitive and very user friendly
- Printouts: by built-in pdf creator in the software system (cloud based)
- Cost: device cost is $349 to $449 depending on which option you choose. A rental program may be available in the near future as well for shorter-term use.
- Advanced recordings such as sequential 12-lead: yes (more on this to be posted later, if and when I get around to it)
- Other aspects and comments: Device is larger than most other handheld ECG devices, which has both pluses (for ease of recording) and minuses (less portable for carrying on ones person). The current version of the printout software shows "Beats Counted" (after stabilizing and for internal analyses) rather than heart rate, which the company plans to revise with the next software update. The batteries can be inserted in either direction.
Source: From the company: http://www.afibalert.com/.
AliveCor / Kardia
Note (9/25/2016) -- This is one of my "Tester's Choice" devices.
UPDATES: (last updated prior to 6/26/2014, new updates coming)
HEADS UP! (added 7/30/2016) A Kardia wrist band for Apple Watch is coming. For a preview, click here.
For their YouTube page with several videos, including news clips, see: http://www.youtube.com/user/Alivecor. For other numerous links, see their main page.
AliveCor is a smartphone ECG device and accompanying app for iPhones, Adroid, and IOS. It has recently been cleared for OTC purchase. It has 24hr/7day interpretation service available for users in the US. It operates through finger contacts built into the device.
It comes in various forms as either a smartphone case in different sizes that fit different phone models or as a small, convenient, handheld wireless device. Even the ones that are actually phone cases operate by wireless, so they also operate when simply near the phone (any phone of compatible operating system, regardless of size) and some users may prefer to use them not attached to the phone anyway. Thus, one can carry them separately or have them at hand and still use them with the phone app even if not using them connected to the phone as a phone case. One can use the system themself or communicate with a physician about the results. Or physicians can carry their own units for use on their patients.
The system, including the accompanying phone apps and computer web app, has numerous options, menus, and settings that can be easily changed, including settings for recording times that can range from 30 seconds to minutes to continuous. It is very flexible and rich in features including even built-in instructional menus that provide information about hearts, ECGs, and heart health. Thus, anyone new to the subject can learn from materials provided directly by AliveCor.
It includes an enhanced filter, one of the best Ive seen, that produces very nice, smooth, ECG traces. If one wants to view the record without the enhanced filter, however, such as a cardiologist looking for very subtle patterns, you have the option to turn the enhanced filter off.
There are various arrangements that can be made to communicate through the system with ones physician. And there are also options for getting recordings analyzed through AliveCors in-house cardiologists and ECG technologists 24/7 for modest per-use charges depending on the service chosen. (Charges beyond the initial purchase price are only for using their in-house analysis service. If not using that service, there are no per-use charges for recording, viewing and printing results, or communicating with ones physician.)
Photo of the AliveCor package (using an iPhone 5 example), Quick Start Guide, and device. The example shown here is the smartphone case for an iPhone 5. The smooth metal contacts on the back surface of the case, as shown, are where one places fingers from the right and left hands during an ECG recording.
Display of phone app ready for recording. In this view, various menus are also shown at the side.
AliveCor being used while recording by simply holding the smartphone case near the phone, not attached. If the case were to be attached to the phone as designed, one would be holding the phone in this manner. The finger contacts (electrodes) for obtaining the ECG signals are located on the back of the case, not visible in this picture but as seen in the first photo above.
Close-up view of display, from a stored recording.
Computer screen view of a section of the list of records.
Onscreen display (via pdf) of an uploaded record, closeup view for details.
Examples of printouts of an uploaded record, left, and an interpretation from the AliveCor analysis service (this example: eCardio ECG technologist), right.
- Physical: (Dimensions vary by smartphone model; weight approx. 1.4 oz)
- Batteries: (smartphone)
- Display screen: (Smartphone or tablet screen.)
- Length(s) of recordings: can be set to different lengths, 30 sec, ... minutes, to
- Time to auto-shutdown: (depends on smartphone or tablet setting)
- Additional cable-wires for adhesive skin electrode recording: no
- Internal or memory-card storage capacity: (depends on smartphone or tablet
- Ability to add comments to recording files: yes: gender, birth date, symptoms,
activity, and comments.
- Device menus, options, flexibility, and ease of use: user friendly, easy to use as app with numerous features. It has an excellent advanced filter, which can be turned on or off (for unfiltered trace). When on, the filter removes a lot of the background noise, such as from skeletal muscles, and makes a very smooth ECG tracing. (Physicians might like the option of turning the filter off to search for possible subtle actual ECG details that might be present.)
- Software or app menus and ease of use: (see above)
- Printouts: Automatically made into pdf files by the system, which can then be
viewed on the computer, printed, and saved separately for file or emailing to
physician or others.
- Cost: USD $199, viewing/printing/storing/sending records on own: no additional
charge; analysis service: $12 for cardiologist within 24 hr, $5 for ECG
technologist within 30 minutes, $2 for ECG technologist within 24 hr, per
analysis. Analysis rates quoted are "introductory pricing".
- Advanced recordings such as sequential 12-lead: no
- Other aspects and comments: This is a feature-rich, flexible ECG device and
app(s) 1-lead ECG system for home, office, and travel use by the general public
with a physician prescription. It can also be used by physicians and other health-
related personnel conducting recordings on their patients while with them. It
records for periods of time chosen by the user, with the record then available for
review or subsequent analysis, printing, saving, and/or sending.
Source: Through AliveCor, following their instructions, at http://store.alivecor.com/.
Dimetek Micro Ambulatory ECG Recorder, DiCare-m1CC
Note (9/25/2016) -- This is one of my "Tester's Choice" devices.
Description coming -- stay tuned/check back later. The -m1CC (only name difference is in the last letter) is a considerably revised and improved device in several aspects compared to the previous -m1CP which is described immediately below; the -m1CP is still good and usable, but the -m1CC is MUCH better.
See: http://www.dimetekus.com/Color-Portable-ECG-Recorder-Dicare-m1CC_p234.html including the company's contact information.
Dimetek Micro Ambulatory ECG Recorder, DiCare-m1CP
UPDATES: (last updated prior to 6/26/2014; 9/25/2016: see section immediately above for a revised version of this device; the revised version is vastly improved in many aspects)
The DiCare-m1CP is a small, compact ECG device with a unique push/roll navigation button/wheel. It has several functions, including quick recording via finger contacts plus Holter, event, and monitoring modes for longer recordings using lead-wires and adhesive skin electrodes. It is one of the smallest and lightest ECG devices available. It is easily worn with the included pouch and necklace cord for longer, Holter-style recordings, and easily carried in a purse or briefcase/backpack, kept in a desk or bedroom drawer, or easily stored in a small space.
It is a stand-alone device with user-managed records on the users own computer (not on a server or in the cloud elsewhere). If the records are to go to a patient's physician, the patient has to either carry the printouts or send email attachments directly to the physician.
This device is very user friendly to operate but requires that the user be guided by his/her physician, be a physician, or otherwise be competent and savvy with ECGs to deal with the records.
When worn as a Holter unit (or event or monitor mode) in the necklace pouch, its small size and light weight allow it to be used unabtrusively and unnoticeablely under clothing during exercise and daily activities. Activity can introduce movement artifacts to the traces but there are still usually many segments of excellent series of heartbeats, particularly when one is inadvertently or deliberately paused or otherwise not moving vigorously, that can be read as good ECG waveforms. The Holter, event, and monitoring functions of this device are perhaps the most important features, with the ability to do quick recordings with the finger contacts as somewhat of an added bonus.
This is one of several products from the company, including at least two portable ECG recorders, available for home use and recently FDA approved.
There is much more information and at least one video available at the websites listed above. There are also several downloadable materials available at: http://www.dimetekus.com/download.
The downloadable items include an app for the android smartphone (see "ECGViewer_android.rar in the download list). I myself have not tested or used that app as I don't have an android phone, but it is described as providing instant communication, ECG data transfer, reading of ECGs, and early warning.
Photo of materials received with purchase: shipping package, Users Quick Start Manual, soft cloth pouch and necklace for wearing during long recordings, lead-wire cables, the ECG device, and micro card reader for transferring files to the computer. The micro card that comes with the unit, in addition to storing recordings, also includes the software, a full user manual, and instructional videos. Also included with the original purchase (but not pictured) is a supply of adhesive skin electrodes for use with the lead-wire connections.
Photo of device at startup Quick option, ready to begin recording with a push of the wheel-button which can be seen at the bottom of the device. (Photo taken under low light to better highlight the display. The display is better than shown here. It is mirror-like and difficult to photograph without reflections.) The display is lighted and works well in the dark, such as during emergency uses at night without turning on room lights.
Photo of recording using the finger/hand contacts. Recordings can also be made using the lead-wire cable and adhesive skin electrodes. The unit is easily worn in the soft cloth pouch as a necklace for long, Holter-style recordings. (As noted in the photo above, screen displays are brighter and better than they appear in these pictures. Because the display surface is so reflective, it has to be photographed under low light or tipped to avoid distracting reflections.)
Two views of a stored ECG record on the device display. Displays of recordings can be scrolled through using the wheel at the bottom. It shows the average waveform at the end of scrolling.
View of computer screen with software running and with a pop-up list of records (by clicking the "Open" button), ready to choose a record for opening. (Note: I changed the names of the files in their folders to reflect conditions of the recordings for my convenience in working with the files later. The system saves the recordings under shorter names by time of recording etc.)
Computer screen view of section of a recording. Comments can be added to the record by clicking on the box at the bottom just to right of center, adding up to 30 characters of comments as shown, then clicking the "save" checkmark button to the right of the comments box. There are several options within the software for different views and analysis, and a scroll bar at the bottom for scrolling through long records.
Printed example of a recording (same as in the computer screen view above.
- Physical: 3 1/2 x 2 3/8 x 5/8 in (90 x 61 x 17 mm), 2.9 oz (82 g) (including batteries and micro memory card)
- Display screen: black-&-white, appox. 2 x 1 in (50 x 25 mm)
- Length(s) of recordings: 24 to 48 sec (settable) for Quick Recording with the finger contact electrodes or, if using the lead-wires for other functions, continuous, that is, until whenever stopped (24 hr default)
- Time to auto-shutdown: display turns off after idle for about 15 seconds but the device itself remains on if recording; if not recording or being used otherwise, the device automatically turns off after 1 minute
- Additional cable-wires for adhesive skin electrode recording: yes, a 2-wire system
- Internal or memory-card storage capacity: the internal storage can only hold one 24 second quick mode recording, but the included 2GB micro SD memory card holds up to 300 hours of recordings; thus, since a single recording can go up to 32 hours, the SD card holds up to at least 8 recordings of 32 hours (or many hundreds to thousands of short-duration recordings)
- Ability to add comments to recording files: yes, up to 30 characters per record (see notes with the figures)
- Device menus and ease of use: clear/intuitive and very user friendly; there are several modes for recording including Quick, Holter, Event, and Monitor (also see Other aspects and comments below)
- Software or app menus and ease of use: clear/intuitive and very user friendly
- Printouts: can be sent to selected printer (including pdf if you have separate pdf printer software).
- Cost: varies considerably depending on supplier, whether they are in stock, and if on sale. Average cost is around $300 but Ive seen them range all the way from $150 and in the $200s to $359!
- Advanced recordings such as sequential 12-lead: yes (more on this to be posted later, if and when I get around to it)
- Other aspects and comments: The device and software has undergone updates and improvements following problems with such things as printing, computer screen displays on different operating systems, etc., so that the system now works much better and more reliably.
The Monitor mode supports visual and audio indication of heartbeats and real-time alarms when the heart rate is out of the present range (normally 60-100 beats per minute).
Finding the software, manuals, and instruction videos can be a challenge for a new user until one understands that it is on the micro memory card, removes the card from the unit when it arrives, and uses the card reader to view things on the computer. I put together my own figure for accomplishing that, as shown:
Note that, to remove the micro memory card, any batteries that are in place have to be removed first, after which the date and time need to be reset when the batteries are reinserted.
Sources: Via the companys web site: http://www.dimetekus.com/Micro-Ambulatory-ECG-Recorder_p238.html (they ship internationally and quickly) and http://dimetekekg.en.ec21.com/Dimetek_Micro_Ambulatory_ECG_Recorder--7968033_7968034.html. The device is also available through numerous suppliers (although they do not all stock them regularly and there may be shipping delays); do a web search for its name.
ECG80A / EKG-80A, from CONTEC (also see their ECG90A) -- printing, and full 12-lead ECG/EKG
UPDATES: description and photos added to webpage 6/28/2014, based on tests that I ran in 2012
*** 7/30/2016: I obtained the latest versions of both ECG80 and ECG90, will be testing them, and adding them to this webpage -- stay tuned ***
This is the smallest and lowest cost stand-alone 12-lead ECG with both a real-time display and printer which fits the definition of "handheld" (whereby the entire functional unit per se fits in one's hand) that I'm aware of. It works great, producing very accurate printed ECG waveforms for all 12 standard leads (sequentially, not simultaneously).
This device may also show up under different names and brands (such as "Rising Med") and is available from international sources and some US suppliers). It is yellow-colored, rounded at one end, flat at the other, and outputs the results using a built-in, narrow-strip printer. It works good if one wants narrow-strip printed output, such as for insurance examiners or others wanting an ECG device with printing and which is light weight and portable. I think the main source is CONTEC Medical. Note that this is a large company (see their home page) which also produces many other ECG devices, including a variety of handheld units as well as various 12-lead and Holter devices. Scroll down in their ECG link to see the yellow printing unit and also browse their many other items (of which the printing unit is the only handheld one that I've seen and tested so far [I have one of their PC-based 12-lead systems, the CONTEC8000, as well as I tested a borrowed unit of one of their Holter systems from a person who had purchased it and wanted me to test it for him; both the PC-based and Holter systems work very well and have excellent software]).
I bought the unit that I tested in 2012, tested it at that time, and subsequently sold it (it worked great, but I didn't need it for further work at the time and, instead, needed the funds for other equipment and supplies). Thus, my results may be somewhat outdated (but hopefully still useful). I recommend looking at the company's webpages for updates. Since I no longer have the device on hand and because there is now a newer version, this description is in a somewhat different format than my descriptions for other devices, in particular I did not bother to provide the section on characteristics. If interested, you can get those details from the company or perhaps eBay listings.
The company also has what appears to be a revised version of the device and greatly enhanced software, named ECG90A. I do not have one and have not tested it, but, based on my results with the ECG80A and what I've read about it, it is worth considering; see the company's description of the ECG90A.
I tried the ECG80A on both a commercial ECG signal simulator (Dynatech Nevada model ECG 100 [one of several simulators that I use in testing]) and a live subject (myself). I then compared the printed ECG waveforms with those from a standard hospital grade ECG machine from both the simulator and myself. I do comparisons of printouts in general by one or more of four methods: (1) overlaying them on a light souce such as a light box, overhead projector, or simply by holding them together at a window, (2) by printing the outputs on transparencies and overlaying those, (3) by using a computer and PowerPoint, making one of the images with a transparent background, and aligning the two images, or (4) carefully making a set of measurements with an electronic or manual caliper, preferably from blown-up images to improve resolution. I used the light box in this case. The 80As printouts were completely accurate, that is, exactly the same as well as could be matched by eye as a regular ECG machine's printouts of the same subject and leads, from both the simulator and myself as subjects.
The leadwire color codes and symbols are IEC rather than the AHA that we're used to here in the US and Canada, which can be a bit confusing to Americans, but the ECG cable includes a great little built-in chart comparing the two so it is easy to refer to and get them correct. (See photo below of the chart that's printed on the ECG patient module.)
The battery seems very good. I did several runs using just the battery and it didn't run low.
Inside the AC adapter it says "220 v" and the manual indicates it is for 220 v, which was initially one of my concerns. However, the manual that comes with it also indicates 110-220 v and the style of the AC plug is for standard (120 v) current here in the US. So, hoping that I wouldn't cause any damage to the unit, I took my chances and plugged it into 120 v to see what happened. It worked just fine, both for running ECGs, printing, and recharging the battery, so no worry regarding that.
The (original version's, which I tested -- later versions have been changed) printing paper was a weird size, 56 or 57 mm wide (the foil wrappers say 57 mm but I measured the width of the roll several times, using different rulers, and always got 56 mm). The grid on the paper roll is 50 mm and the manual says it uses 50 mm rolls. The grid printing on the rolls is on the outside of the roll. All of the small rolls of ECG paper that I have previous experience with are either 50 or 60 mm (or larger, for some machines such as Marquette MAC PC). Both 50 and 60 mm rolls are readily available from online suppliers. 60 mm is definitely too large for the printer (I measured the space). 50 mm would probably work okay (I didn't try it). What I recommend, if one is going to be doing a lot of ECG printing and you end up with an early version of this device (measure it to be sure), would be to get the paper from the original company, an ECG paper supplier that has the (actual) 56 mm size, or else make sure you get a later version made for standard 50 mm paper.
The Auto printout, including a preliminary section with printed blanks to fill in the name etc. plus each of the 12 leads in sequence requires 42 inches (just over a yard or meter) length of paper and takes 1 minute and 20 seconds to print (I timed it). The ECG80A (at least the version I tested) does not include measurements or interpretation (at least not in the device itself; it might in the companion software); you have to do measurements and interpretation yourself (which is safest and preferred method, by at least some of us anyway ... a lot of what I have been researching with ECG machines recently involves analysing machine measurements and interpretations; they are much more variable [when done with large numbers of repeated runs on the same machine and subject] and less reliable, including the measurements, than most people would realize or expect! ... the printed ECG waveforms, on the other hand, seem to be consistently accurate and reliable, across repeated runs and most machines, so a human doing the measurements and interpretations can be quite consistent [pending the difficulty of the interpretation and the reader's competence]). My understanding from the company's webpage is that the newer ECG90A DOES have measurement and interpretation capability (although I don't know if it is built into the device itself or via the computer software).
The Manual printout prints continuously, as long as you want, until you stop it (by pressing the print button again while it's printing) or until the paper runs out. Thus, the manual print is an easy way to do a rhythm print, such as standard for lead II.
It's very easy to switch back and forth between Auto and Manual, so that is no hassle.
A note regarding how much time to record ECGs: if you need 6 seconds or more of printout, it is easy to do on the manual setting ... but it will use a lot of paper! The auto setting for the 3-second segments, plus a manual recording for more on one lead, such as lead II for a standard rhythm strip, would seem to be sufficient unless there is an arrhythmia going on or if individual heart beats vary noticeably for some other reason and you need another sample. Anyway, just a thought about the paper use.
The version of the user manual that I received was written in "Chinglish". That is, it's readable, but with lots of grammatical errors and/or idiosyncrasies. It's also not as complete as I would like. But it worked okay and the learning curve for using the machine is not too bad.
When I tried running the machine on myself, the first couple times it wouldn't run but said "error code [with different numbers]". I figured it was the adhesive electrodes I was using. So I changed the electrodes on myself and then it worked with no problem. Thus, it's important to have proper skin contacts (as with most machines). The unit comes with limb clamps and chest suction cups, but I prefer the adhesive skin electrodes. The unit also came with lead-wire clips for either tab or snap (I tried both) adhesive electrodes. The clips work fine, so you don't have to mess with the limb clamps and chest suction cups (plus electrode paste and all the clean-up, etc).
The unit I tested did not store any records internally, but just printed from real time. Later versions may be different.
There appears to be a connection for uploading to a computer or external monitor, but my unit did not include a cable to go with it, no software CD, and I didn't further pursue that aspect. From current descriptions from the company, there appears to be software. I have another ECG machine from CONTEC (ECG8000) and it works great, with excellent software. So I'm guessing that the software which accompanies these handheld printing devices also is good.
I was able to cut up a printed record and put it on an 8 1/2 x 11 inch piece of paper. I just did it easily and simply with scissors and tape.
Note re. the photos: The unit still has the protective thin film of transparent plastic on the monitor/display screen, as can be seen in the photos (and the views are through that thin film covering the screen).
What I got in the package that I purchased (contents may vary with purchase, particularly with newer versions of the device [plus software]): top photo, upper layer of packaging -- battery charger/power adapter, the ECG device/recorder, and several rolls of paper (one of which I loaded into the paper holding section of the unit); bottom photo, lower layer of packaging -- cable/lead wires/patient module, power cord, and electrode clips and clamps (I prefer the clips to use with single-use adhesive skin electrodes).
The recorder while real-time monitoring (with roll of paper in top section, edge of paper visible at bottom of paper holder clear-plastic cover).
Recording (and printing) while connected to an ECG simulator.
Closeup of the cable/lead wires patient module, showing codes for both IEC (European) and AHA (American) systems.
View showing both the screen monitor and printing out as the recording is made.
Section of printout from a recording.
Closeup of printout. (It looks like the width of the printout strip varies. However, that is just artifact from the photo and unrolled but still somewhat curved paper. The actual width is the same throughout the strip.)
Start of a section of printout, showing space to write ID etc. and a closeup of lead I. (Three second segments per lead when printed in auto mode, or continuous when in manual mode.)
Cut-and-taped, assembled strips on an 8 1/2 x 11 page. The apparent variation of strip widths is simply from my cutting out the sections by hand with scissors, not with a paper cutter. Also, depending partly on the scale you use, the red grid lines might not look very good. On the actual printout, such as can be seen in the views above, however, the grid is standard (1 mm little boxes, 5 mm big boxes), normal, and high quality.
- Physical: 7 1/2 x 3 1/2 x ~ 1 1/2 in (190 x 90 x 40 mm), ~ 1 lb (450 g)
- Batteries: internal lithium rechargeable (plus 100-240 V, 50/60 Hz AC)
- Display screen: (see photo)
- Length(s) of recordings: 3 sec./lead or continuous
- Time to auto-shutdown: (not noted)
- Additional cable-wires for adhesive skin electrode recording: yes, only way (no metal finger contacts)
- Internal or memory-card storage capacity: (not certain, believe so in newer versions)
- Ability to add comments to recording files: (on computer via software? ... not tested); by writing on printed output
- Device menus, options, flexibility, and ease of use: simple and direct buttons
- Software or app menus and ease of use: (not tested)
- Printouts: yes
- Cost: approx. USD $300 for ECG80A, not certain of cost for newer models
- Advanced recordings such as sequential 12-lead: yes
- Other aspects and comments: full 12-lead recorder, with built-in printer
Sources: http://www.contecmed.com/index.php?page=shop.product_details&flypage=flypage.tpl&product_id=92&category_id=11&option=com_virtuemart&Itemid=605; there is also at least one seller on eBay connected to CONTEC, plus other sellers on eBay (including some that I've seen from India) and the device is marketed under other brand names and there may be US suppliers ... do a web search.
UPDATES: (last updated prior to 6/26/2014)
For a video introduction to the device or to purchase, see: http://www.ecgcheck.com/. Physicians and patients can get support from Cardiac Designs by emailing email@example.com or by calling 512-582-2453 during business hours.
The ECG Check device is a low-cost phone case and accompanying app that works with iPhones 4s and newer. ECG Check is simple-to-use and provides straightforward ECG information. Despite its low cost, it provides highly accurate 1-lead ECG recordings.
The ECG Check system is available in several modes: OTC, prescription, and physician. ECG Checks OTC mode is designed with general-public users who are not interested in looking at their ECG traces, but who just want to take a quick recording for the basic information for themselves and/or which they can send simply and directly from their iPhones to their physicians.
Users wanting to upgrade to the prescription mode can obtain the prescription from their physician then easily submit an image of their prescription when prompted by the app, using the camera on their iPhone. Physicians wanting to upgrade to physician mode can submit their NPI code through the app.
Users with their ECG Check systems upgraded to full functionality, beyond OTC mode, are still very easy to use. Patients record ECGs and can send the records to their physicians the same way in both OTC and prescription modes. However, in prescription mode, the patients can also view the full recordings including the waveforms on the iPhone (including during recording) and in the results (in pdf format) sent to themselves. The recordings can be downloaded from email, viewed, printed, and filed as electronic medical records (EMR).
ECG Check is designed to fit on iPhones. But because the system employs Bluetooth to communicate with the device, it works whether used as an actual iPhone case or when just held within range of the iPhone, not attached (regardless of whether the 4s/5 case is the same as the iPhone version). It is also possible to use ECG Check with iPad 3 or newer.
ECG Check reports show beat-to-beat heart rates for each pair of neighboring beats. They can be viewed in the saved records on the iPhone, on a sent pdf file opened on a computer screen, or printed. I found that to be a really nice feature, which is especially useful for evaluating beat irregularities, or arrhythmias, such as afib, PVCs, PACs, etc.
Photo of materials received with purchase: plastic packaging, Quick Start Guide, and iPhone case/device (plus a downloadable app). The case is shown from the back, where the shiny metal finger-contact electrodes can be seen.
Photo of app startup, ready to begin recording.
Recording while holding the device near the phone, not directly attached.
View of a section of a list of recordings on the iPhone.
View of a stored ECG record on the iPhone. (Note the PVC at the start of the record.)
Close-up of a section of recording, as expanded on the iPhone. The automatically measured beat-to-beat heart rates can be seen in this view.
Close-up view of a section of a pdf report, as viewed on computer screen monitor. The beat-to-beat measures of heart rate between neighboring pairs of beats can be seen in this view.
Printout from a sent pdf record.
- Physical: (Dimensions vary by iPhone model; weight approx. 1.2 oz)
- Display screen: (iPhone [or iPad] screen.)
- Length(s) of recordings: can be set to different lengths, 30 sec, 40 sec, 1 minute, or 2 minutes
- Time to auto-shutdown: (depends on iPhone [or iPad] setting)
- Additional cable-wires for adhesive skin electrode recording: no
- Internal or memory-card storage capacity: (depends on iPhone [or iPad] memory)
- Ability to add comments to recording files: only gender and age; comments can only be added by changing the name of the saved records pdf file name to include key aspects
- Device menus and ease of use: simple menus, clear/intuitive and very user friendly
- Software or app menus and ease of use: (see above)
- Printouts: automatically made into pdf files by the system, which can then be sent by email from the phone app, viewed on the computer, printed, and saved separately for file or emailing to physician or others
- Cost: MSRP: USD $129; no additional per-use charge for recording, viewing/printing/storing/sending records
- Advanced recordings such as sequential 12-lead: no
- Other aspects and comments: This is a low-cost, simple, quick and easy, no-frills 1-lead ECG device. It is excellent for anyone wanting that. The automatic beat-to-beat heart rate measurement is a very nice feature.
Sources: http://www.ecgcheck.com/ and Amazon.com.
UPDATES: (last updated prior to 6/26/2014)
For the the HeartCheck Pen YouTube introduction to the device, see: http://www.youtube.com/watch?v=Pk_dNPKmDD0. For other links: YouTube page with all of their videos, and an Executive Informational Overview report on CardioComm Solutions, Inc..
The HeartCheck PEN ECG device is the first FDA cleared and Health OTC handheld ECG recording device. It also has 24 hr 7 day a week full ECG interpretation service by a physician. The name of the cloud-based service is GEMS Home. The HeartCheck PEN manufacturer, CardioComm Solutions, offers the first ECG interpretation free; subsequent ones cost a modest amount. In addition to the full interpretive service of an in-house physician, they also offer a lower-cost triage service with readings by certified ECG technologists.
Because it is OTC and a prescription is not required, anyone can get it, use it themselves (including with the interpretation service when desired or needed), and/or communicate the results with their physicians. Contact with ones own physician is not required but always recommended unless one is certain that there are no heart-health concerns or if one is otherwise already connected with a cardiologist and simply wants a handheld device for your own use.
The device operates through finger contacts, is small, compact, and easily carried in a pocket, purse, briefcase, or kept readily at hand. It includes a clip on the back for a shirt pocket.
Package of materials received with purchase: plastic shipping and storage box (upper left), cable for uploading stored records to computer (upper right), printed manual (lower left), and HeartCheck PEN device (lower right). Software is downloaded from online.
Recording an ECG.
Close-up view of display screen, from a stored recording.
Computer screen image of software menus at startup.
Computer screen view of section of list of records, with one highlighted, to view report and/or submit for monitoring review (see next images).
Onscreen display (via pdf) of an uploaded record, closeup view for details.
Onscreen display (via pdf) of an uploaded record, left, and an interpretation (via pdf) from the GEMS Home service, right.
- Physical: 5 3/16 x 1 3/16 x 3/4 in (132 x 30 x 20 mm), 2.5 oz (72 g)
- Display screen: 1 x 1/2 in (25 x 12 mm), color, lighted so can be used in dark
- Length(s) of recordings: 30 sec
- Time to auto-shutdown: choice of 10, 30, 60, or 120 sec (no manual off, have to wait for auto-shutdown)
- Additional cable-wires for adhesive skin electrode recording: no
- Internal or memory-card storage capacity: 20 records
- Ability to add comments to recording files: yes, by Diary Entry for uploaded records
- Device menus and ease of use: user friendly, easy to use -- recording, review/playback stored recordings, system setup (date and time, sound, speed of playback, filter, auto-shutdown time
- Software or app menus and ease of use: several menus and options that are intuitive and user-friendly
- Printouts: Automatically made into pdf files by the system, which can then be viewed on the computer, printed, and saved separately for file or emailing to physician or others.
- Cost: MSRP: USD $259, viewing/printing/storing/sending records on own: no charge, Interpretation service: no charge for first interpretation, $12.50 each thereafter, Triage Service: $4.99 per analysis.
- Advanced recordings such as sequential 12-lead: no
- Other aspects and comments: One of the smallest devices, for convenience and portability; useful for quick recordings for own review/monitoring or to send to physician. The display screen is very small, but easily read and the small screen is a consequence of a small device.
Sources:http://www.theheartcheck.com/Portable-EKG-Machines.htm and several other online sources (do a search)
UPDATES: (last updated 7/22/2015)
Additional link and comments as of 7/22/2015: I have not tested the latest version of InstantCheck and its software myself, but I heard directly from another person, whom I thank, who just got one (July 2015) direct from the company and contacted me.
CAUTION: InstantCheck now has a continuous mode, suggesting a Holter-type function. However, it is only the measurement and display that run continuously (up to two hours), it does NOT truly record continuously. If a recording is made while in the continuous mode, it only records and stores the last 30 seconds. Thus, buyer/user beware!
Other recent changes: Good: Another added feature is that it now includes a wireless function that will broadcast real-time ECG monitoring to a computer display. (The default for wireless is "off" to save battery power.) Good: The latest user manual is greatly improved over previous editions, with only minimal "Chinglish". Not so good (particularly in the face of fierce competition from other recent devices that have more and better features at much lower cost): the price from many of the sources has increased substantially.
This is one of the first three handheld devices that I tested and reported. It is still available, still the same quality, and still very popular among users. Earlier problems, such as occasional failure of the cable between the main unit and the display screen in the lid, have been corrected (and the company may offer to replace or repair older units that fail even after the standard warranty period). I believe the device has been updated since my original review and I know that the software has gone through several revisions (see added link immediately above).
InstantCheck is a more complete and more expensive, slightly smaller but slightly heavier cousin of ReadMyHeart (see below), manufactured by the same company (DailyCare Biomedical Inc.) The recorder has several more options than RMH, a complete menu, and displays the actual ECG tracings during recording and review of records. It also has computer software that is further developed and refined (while still being very user friendly) compared to RMH.
IC's display of the actual ECG as a monitor during recording and subsequent review of records permits a reading of the ECG by a cardiologist or anyone who can read ECGs, as well as confirming that a good record is being obtained during the time of recording. IC is good for anyone who is more serious about ECG recording and/or who wants good records. The main tradeoff is that it also costs more than most of the other handheld devices.
Display of a recorded ECG.
View of computer screen, software, and an uploaded record, with added comments.
Example of a printout.
(Note: these characteristics are based on my much earlier (2006-2008) personal testing plus a few updates based on what I have heard from other persons with newer versions, see "Other aspects and comments" below.)
- Physical: 4 7/8 in. x 3 1/8 in. x 7/8 in. (12.3 cm x 7.8 cm x 2.3 cm); weight with batteries approx. 5.5 oz. (~140 gm)
- Batteries: 2 standard 1.5 v size AAA
- Display screen: real-time monitor plus heart rate during recording; then, after recording it shows record number, date and time, HR, ST, QRS, and a simple interpretation of the recording; display is not lighted but the recorder includes a red light that displays on the panel during recording, which makes it useful for knowing when a recording is finished at night in the dark without room lights. UPDATE: Latest version also includes wireless broadcast of real-time monitoring to a computer for display. (The wireless function has to be turned on by the user. By default it is turned off to save battery.)
- Length(s) of recordings: 30 seconds following a brief initialization time. UPDATE: Latest version includes "continuous mode" but that does NOT include continuous recording. When in continuous mode it means "measurement and display", only the last 30 seconds are recorded.
- Time to auto-shutdown: 1 minute from last time one of the buttons is pressed (and after a recording ends, if no further action taken)
- Additional cable-wires for adhesive skin electrode recording: yes, 2-wire
- Internal or memory-card storage capacity: 100 records
- Ability to add comments to recording files: yes
- Device menus, options, flexibility, and ease of use: starts up with message and ability to either go to the menus or start recording as desired; easy to use and thorough menus, including scrolling down through the records and review of individual records -- with stopping and restarting as desired; records are retained in the recorder after upload/transfer to computer and may be deleted (all at a time) from or kept in the recorder as desired; audible beep at startup and shutoff so one knows when it comes on and goes off
- Software or app menus and ease of use: excellent software, including printout of one, full, 30 second record per page, with standard grid and measurements
- Printouts: can be printed from the uploaded records using the software; standard grid and measurements
- Cost: latest, wireless version from under $500 up to $800, depending on source
- Advanced recordings such as sequential 12-lead: yes, using the lead wires
- Other aspects and comments: Compact for easy carrying and storage; quick start and convenient, with option to go either to the menus or start recording; display of actual ECG monitoring during recording (and subsequent review of records); numerous options available through the user-friendly menus; easy transfer of data to computer with excellent analysis and printout; I myself have used the device many times over a several-year period and we have used it in university lab courses with students; the only long-term problem that I encountered in the (original) units I used is that batteries go dead when left in it unused after several days or a few weeks, thus, it needs to be stored with the batteries out or have the batteries replaced after storage (along with resetting the date and time). However, I heard from another user who did not have that problem. His unit, apparently a revised version, went for several months between the need to change batteries, so the problem may have been fixed. (I would appreciate hearing from others who get or already have the InstantCheck as to whether or not they encounter short battery lives. If it is no longer a problem, I'll drop these comments.)
Sources: http://www.favoriteplus.com/instantcheck-handheld-ecg-ekg-monitor-fp-ich.php, http://www.dcbiomed.com/webls-en-us/InstantCheck:V4.0.html, and several other online sources.
UPDATES: description and images added 07/08/2014
http://www.choicemmed.com/list.aspx?id=45 (and click on the MD100E from the list). For links and sources, do a browser search for "md100e ecg", e.g.: https://www.google.com/#q=md100e+ecg.
Note: I tested some of the other, earlier versions of this device but did not like them and did not include them in this review of handheld devices. The latest version, however, has gone through several revisions, is much improved, and there are many aspects (but still not all, particularly with the accompanying software) that I really like about it. It can produce (with good electrode placement) some of the best ECG tracings that I've seen, including during strenuous activity.
Most things involve trade-offs. However, this ECG machine is an example of an item with somewhat extreme trade-offs. The device itself is great and it produces some excellent ECG records and printouts. But the software, at least the English version that I got (3.7.3), is full of quirks and, at least initially, very difficult to work with!
First the good points: the recording device is excellent, attractive and easy to use, a good size for portability (and possible to wear for long, continuous recordings as a Holter device simply by sticking it in a shirt pocket), has great settings with many options, the display screen is in color and bright (including works pretty good outdoors in bright light [which many of the handheld ECG device display screens don't do very well], has both finger contacts and lead-wire cable options, audible heart beeps if you want to turn that feature on, the automatic shut-down can be set for any length of time, large internal memory capacity (plus microSD card) for storing large numers or many hours of recordings, has built-in and on-computer-screen (real-time) monitoring capabilities, and can be run for long periods (hours) like a Holter monitor while one is going about daily living, exercising, or overnight while sleeping (the time when many cardiac irregularities have a tendancy to occur). The printouts are great (although the automated interpretations aren't always correct, as will be illustrated below ... but such errors happen with virtually all ECG machines, including the best and most expensive hospital-grade systems). When the device is running, interpretations (such as "PVC" or "trigeminy" pop up at the bottom of the display screen in real time, as they happen).
Now for the current (subject to revision) problems with the software ...
(Note: The software version I used was 3.7.3. From searching the internet, I believe there is now a version 6.7 which might [or might not] have corrected some of these problems [or might have only revised the software to work on 64 bit computers and the latest versions of Microsoft Windows]. But I have not been successful when trying to download the latest version [the download page has problems that I have not been able to solve nor have I been able to contact the company directly]. If anyone reading this can provide better information, including perhaps someone from the Choicemmed company or a distributor or someone who owns the latest version of the device and software, I would greatly appreciate hearing from you.)
If you read the software manual that comes on the CD, play around with the menus and options extensively, have patience with such things and hang in there, eventually you get it figured out. Then, if you use it often enough to remember how to do it or make notes to yourself for future reference, you'll be okay and it's not so bad. Otherwise, the next time you go to use it, you'll have to figure it out all over again! Hopefully, it will be (or perhaps already has been) revised to take care of these problems. The main software difficulties that I encountered are (1) confusing menu wording and figuring out how to do what you want it to do (including getting the records to upload from the device, working with the records in different ways and [next point]), (2) getting the record you want printed, (3) not being able to add comments to the records (so you have to keep separate paper records to keep everything straight and associated information together, or simply write it manually on the printouts), and (4) dealing with long recordings, which the system breaks down into a large number of short records rather than keeping everything together in one long record.
There are also a number of other strange things that one has to deal with. For example, when records are exported from the computer files, such as to make backup copies, it (sometimes but not always?) also deletes the files from the computer! When that happens, you then have "backup" but no "original" files! The only way to have both is to first make the backup, then re-import the backups back into the computer! It does, incidentally and however, leave the data on the device itself (and/or microSD card) unless you deliberately erase them from there.
To upload records that are on the SD card, you have to remove the card from the recorder, insert it into a USB SD card reader, and connect it to the computer. You can't upload records from the SD card, only from the internal memory, by connecting the recorder to the computer with the USB cable.
While mentioning the microSD cards, I should also caution that the MD100E device, at least the one I got, only works with the original style of microSD up to 2gb size, not the newer, larger capacity kinds of microSD (microSDHC or microSDXC), even though the newer versions are the same physical size and shape. I discovered it the hard way, by buying a couple of microSDHC cards then having them cause problems in the MD100E (it locked up until I pulled the batteries out to stop it). So, if you want to buy additional microSD cards, be careful (and you'll also find it difficult to find them in stores -- I found them on eBay, where they are plentiful [but you still have to be careful to get the correct ones that are not HC]; I also found them at a local Barnes&Noble book store [where they are used in the B&N Nook reader].)
I'll discuss some of the software problems further as we come to them in the photos below.
The basic package that comes with a purchase: ECG recorder, instruction manual, software, optional cable and lead wires, plus USB cable for connecting the recorder to a computer for uploading records.
Views of the ECG recorder's left and right ends, respectively, showing the metal finger electrode contacts.
Using the recorder with the metal finger contacts. The blue bar graph below the traces shows the time progress of the recording (in this case, 13 seconds into a 30 second recording). The left edge can also be held in the palm of the hand, on the left ankle (to obtain a lead II) or at various positions of the chest to obtain chest leads (V1-6).
The recorder can also be used with a cable and lead-wire connection (shown here connected at the top of the device). The display screen in this image shows the startup menu. The displays also indicate date, time, number of internally-saved recordings, battery status, and indication of present function being shown. Note: To turn the recorder on or off, you have to press and hold the power button (at the top edge of the device, not visible in this image) for several seconds (just pressing it briefly is not sufficient).
After a recording is finished, the machine analyzes and saves it.
The automated analysis includes heart rate (HR), smiley (if normal result) or sad (if abnormal result) face icons, and a brief interpretation. (See section and images further below for correct versus incorrect measurements and interpretations.)
Example of a list of saved records in the recorder, which can be opened and reviewed.
Example of a record with a PVC (premature ventricular contraction/complex). Note the scroll bar below the tracing. You can step back and forth through the record to any point.
Example of the (correct) automated analysis of a record with PVCs (called "suspected early beat"s or, during recording, "PVC"s), along with the accompanying sad-face icon.
Another example of a record review, in this case of a normal sinus rhythm (NSR), or as called by the MD100E, "Stable waveform".
View of the computer software's (v 3.7.3) opening menus screen. To me, the wordings are not intuitive and, in fact, confusing. I'm wondering if maybe they weren't translated from Chinese to English by a computer?! The "ContinueDataDisplay", upper right corner, is for the real-time monitor, when the recorder is connected to the computer. "ContinueDataReplay" is for the records that were saved (by the computer when monitoring or on the SD card when monitoring with "ContinueDataDisplay"). "EasyDataReplay" is for uploading, saving, and reviewing recordings saved internally in the recorder or by importing (including long, Holter type, records) from the SD card. "ArchiveManager is for entering or editing patient information. "CommonSense" is for information on trouble-shooting a few problems and some basic background information on the subject of ECGs. Each of these entry menus, once opened, then have further menus.
If the recorder is connected to the computer by the USB cable, when "EasyDataReplay" is opened, you get this screen. To upload records, press the "Read Data" button at the bottom of the page.
Data uploading from the recorder. After uploading, if the "Add in Archives" button is pressed, the records are then saved and can be viewed in "Record Management".
A list of uploaded, saved records. This series includes part of the list of short segments from a longer, Holter-style recording which included a bicycle ride.
I'm going to use number "211" as an example. The segment was recorded prior to starting the bike ride. I put "211" in quotes because it is only 211 in the current list. If more records are added, the record numbers can change! Note that 211 has a PVC (5th full beat in from left) which serves as a convenient marker. (The automated interpretation, "Analyse Result", missed the PVC.) The heart rate of "80" is correct (or nearly so, actual is 82). At the bottom of the page "Add" means "import". This page does not have a button for printing. To print our example, 211, one has to go to the "Data Replay" page (next image below).
The "DataReplay" page has a button for printing (lower right corner). However, it does not list the record numbers!!!!! Arg!!! To know what record you are on is a bit of a challenge and requires some added work! I have the page including (and showing) record 211 (see the PVC marker). So how does one figure out how to select a particular record??? Well notice that this page shows 15 records per page and shows what "DataReplay" page you are on (15 out of 28, currently). Okay, so you need to know what record you want (from the numbers listed on the "RecordManagment" page), then do some calculations by dividing the record number by 15, to determine which page it is on and where on the page, in this case, 211/15 = 14.07, or 14 pages plus 1/15th. Thus, go to the next page, 1st record, after page 14, that is, the first record on page 15. Then you can print the record (next image after this one, below).
Here is the printed record, an excellent printout, after jumping through the hoops to get it printed. (The "Analyse Result" is incorrect, as indicated above.)
Here is the "Record Magement" page showing later records from the bike ride, highlighting a record after a rigorous segment of bike riding (uphill into the wind) when my heart rate reached a peak (around 150, the listed HR is correct). Where would this record be found on the "Data Replay" page? You can do the math, if so inclined. (I did it, to get at the printout shown further below, but I'm not going to show all the steps again.)
I want to point out that, despite the hassles of working with the software, the waveforms themselves are excellent! This segment of recording is nearly clean of muscle artifact despite a very heavy workout. Most recorders, including some of the best, very expensive medical Holter systems, would probably have a lot of artifact at this point. Part of the solution (including the MD100E doing its part) involved electrode placement. Rather than using the recommended (by the manual) positions, I put the "RA" on my right clavicle, "LA" on a rib under the arm (at a normal position for V6), and the "LL" on my lowest rib on the right side. (I do extensive work with ECGs, including 12-lead systems and Holters, and experiment a lot with different electrode placements on different persons, pending individual wave axes and other considerations.)
One thing nice about the "Data Replay" page is that it shows several records at the same time, which is handy for comparison. This set of 15, for example, is from right after I stopped bicycling, am resting (while standing over the bike, then getting off the bike) and the heart rate is beginning to recover from the workout. The first line (note the green box at the upper left) is of a record where the HR is at 140. See the next image, below, for the end of this set of 15 records.
The 15th of this set of recording-segment records, see the green box at the bottom right. The position of the green box (and displayed segment) is moved by simply clicking the mouse to different positions on the page. HR has dropped to 102 at this point.
Next three printouts are a series from the bike ride, ending up with a resting record from several minutes after the ride was completed (but HR was still slightly elevated, from what is called EPOC, or excess postexercise oxygen consumption [what used to be called, incorrectly, accumulated lactic acid "oxygen debt"]). I pointed out (added arrow and white box information) that the "Analyse Result" information was not correct; also see next set of images and discussion after these printouts. There are a few extraneous wiggles, not true heart waves (P, Q, R, S, and T waves), thus, some slight artifact appears here and there, but it is not excessive. Some artifact is expected in most ECG recordings; you learn to note but not count it.
Computer screen view while the real-time monitor was running. The arrows and information in white boxes were added by me. This is a frozen snapshot from a dynamic monitor with a moving ECG trace. It moves across the screen from left to right, as with most real-time ECG monitors, then returns to the left and starts over with the continuing tracing. The active, moving point is shown in these examples as the break in the ECG line just past the end of the white arrow. This example had correct automated measurement of heart rate (HR) and interpretation. For comparison (examples of incorrect measurements and/or interpretations), see the subsequent illustrations.
NOTICE: Automated measurements and interpretations require a healthy dose of CAUTION!
Although the following examples involve the MD100E, virtually ALL ECG machines/devices with automated measurements and interpretations are potentially vulnerable to these problems. (Even cardiologists and ECG technologists make errors, but they are usually less serious and more likely to be caught and corrected than with automated results.) As most people who routinely work with ECGs know (or should know), NEVER TRUST OR RELY ON AN AUTOMATED INTERPRETATION. My comparative research with standard, hospital-grade 12-lead machines, not yet published, has demonstrated that the same principle applies also to automated measurements -- they can be highly variable (even with repeated identical inputs) and not always reliable. Computer/machine algorithms have more difficulties with measuring and interpreting ECG waveforms than do human eyes and brains that are trained and experienced. It is better to trust your cardiologist (or a professional ECG reading service using live persons) rather than your machine.
Okay, here are some examples I encountered while using the MD100E.
To begin with, see the image above. It (and many, if not most) of the results I got with the MD100E were correct, including those that usually identified the presence of PCVs (and called them either "PVC"s or "suspected early beat"s). The following illustrate problems with automated measurements and/or interpretations.
The following example came from the same series of runs as the one above which was measured and interpreted correctly. This one counted T waves (plus a few P waves?) as separate beats and, as a result, essentially doubled the measured heart rate from what it actually was. I was watching the monitor on my computer (with the heart icon beating and accompanying audio beeping) and noticed the double counting as it was happening. Because of the high, incorrect automated measurement, the automated interpretation (as "tachy", or tachycardia) was also wrong. (The arrows and information in white boxes were added by me.)
In this example, the heart rate was correct, but the automated interpretation missed the presence of a PVC. (The arrows and information in white boxes were added by me.)
Here is an extreme example of automated mistakes for both measurement and interpretation. The machine's internal algorithm got the heart rate way wrong and completely missed both the atrial fibrillation and PVCs! The correct heart rate is 114, not 76. The actual HR was determined manually by simply counting the beats (starting after the first, incomplete one at the upper left edge, which marks the beginning) for the 30 second record and multiplying by two, for the heart rate per minute. (The arrows and information in white boxes were added by me.)
Not all of the records I obtained with the MD100E had automatically-measured/interpreted mistakes. But the examples above and others did, which must caution anyone about trusting or relying on ANY automated results by ANY ECG machine or device. The actual ECG waveform tracings themselves (by MD100E as well as virtually all brands and models of machines/devices), on the other hand, have all been consistent and reliable (aside from artifact problems, usually from skeletal muscle or other sources including external electrical interference). Thus, the tracings themselves (aside from artifact) can be trusted. The problems happen when software tries to measure and interpret the waveforms. That job is best left to a live, trained and experienced human, namely your cardiologist or a professional ECG reading service.
- Physical: 5 1/2 in. x 2 7/8 in. x 15/16 in. (13.8 cm x 7.5 cm x 2.4 cm); weight with batteries approx. 6 oz. (<100 gm)
- Batteries: 2 AA
- Display screen: 2 1/2 in. x 1 3/4 in. (6 cm x 4.5 cm), large, bright, color
- Length(s) of recordings: 30 sec or continuous for as long as desired (via monitor viewing/saving or by saving on microSD card)
- Time to auto-shutdown: user settable
- Additional cable-wires for adhesive skin electrode recording: yes, 3-wire
- Internal or memory-card storage capacity: 100 built-in memory, plus microSD card
- Ability to add comments to recording files: no
- Device menus, options, flexibility, and ease of use: easy/user friendly
- Software or app menus and ease of use: NOT user friendly, at least not in ver. 3.7.3, see all of the discussion and images above
- Printouts: yes, excellent
- Cost: $259
- Advanced recordings such as sequential 12-lead: yes
- Other aspects and comments: excellent ECG recorder, records, and printouts; but the software (at least 3.7.3) is a real challenge!
Sources: For links and sources, do a browser search for "md100e ecg", e.g.: https://www.google.com/#q=md100e+ecg. The device is commonly listed on eBay.
PC-80 ... for updated versions, see comments under "Device characteristics" plus the next device below (PC-80B Color)
UPDATES: (last updated prior to 6/26/2014)
One of the first three handheld devices that I tested and reported. It is still available and, from what I understand, still liked by many persons, particularly elderly and those new to such devices who want low cost and only the most basic of systems.
The PC-80 may be about to be discontinued and replaced by its newer sibling, PC-80B Color, which is considerably different, has many added features, more flexibility, and, has corrected some of the drawbacks of the original PC-80. For details on the PC-80B Color, see next device described further below.
The PC-80 is small, lightweight, robust, and handy. It is for someone on the go wanting a unit that takes up little space and for fast recordings. It would take up little room in a briefcase or luggage or even fit easily in a purse.
In its original version (including the software), it is most useful for determining basic arrhythmias rather than full ECG analysis. The software and printouts provide the least useful ECGs for resting ECGs but seems to allow arrhythmias to show through background noise slightly better, that is, it seems less vulnerable to ECG artifacts than some of the other devices. It accentuates or focuses on the R wave, with diminuation of the other waves, including T. It represents an early stage of software developent. Aside from software issues, it is a great stand-alone ECG recorder that records and stores ECGs for later review by oneself or a cardiologist. As with many of today's devices, one can take or send the printouts to their physician or take in the device itself to show the results on the recorder's display screen..
PC-80 starts fast, goes right into recording, and has a fast (30 second) auto shutoff if no further action is taken. It has menus with several options and a rocker panel to select among various choices. Because it starts recording at powerup, one has to either do a recording at the start or wait for it to go through the routine before accessing the menus. The advantage is that it gets right to recording for someone that wants to record as quickly as possible. The downside is that going into recording first can get in the way of going to the other functions.
View of display screen.
Computer screen view of software and an uploaded record. The software uses it's own, basically nonstandard grid and does not provide measurements of ECG waves, just HR and a simple interpretation of whether the ECG is "normal" or not.
Example of a printout, very basic, without measurements beyond HR and without the option of including user comments (also with its own, nonstandard grid, although still at the standard 25mm/sec speed).
But the PC-80 does have a summary feature for printing out summary ECGs for all records, which is very nice.
- Physical: 4 3/8 in. x 2 1/8 in. x 5/8 in. (11.2 cm x 5.5 cm x 1.7 cm); weight with batteries approx. 4 oz. (<100 gm)
- Batteries: 2 standard 1.5 v size AAA
- Display screen: active real-time monitor while recording; after recording it displays record number, date and time, HR, a smiley (or sad) face, and a simple interpretation of the recording after it's completed; at the press of button for screen lighting, the recorder can be used and viewed at night (when many arrhythmias commonly occur) without needing to have room lights on
- Length(s) of recordings: 30 seconds
- Time to auto-shutdown: after 30 seconds from last time one of the buttons is pressed (or analyzing and storing a recording, if no further action taken) -- which is not much time and one has to be quick or else restart the device for using functions beyond recording
- Additional cable-wires for adhesive skin electrode recording: 3-wire
- Internal or memory-card storage capacity: 24 records, after which new ones replace the first ones; records are retained in the recorder after upload/transfer to computer and may be deleted (one at a time) from or kept in the recorder as desired
- Ability to add comments to recording files: no
- Device menus, options, flexibility, and ease of use: starts up with message and instructions then starts recording; thorough menu, including scrolling down through the records and review of individual records -- with stopping and restarting as desired
- Software or app menus and ease of use: The original software has easy transfer/upload of data from the recorder and moderately user friendly menus, but at the same time is also somewhat awkward, does not use the standard grid pattern (although it is still 25mm/sec), and does not allow entering user notes and comments to supplement the records. The software also seems to accentuate the R wave at the expense of other waves, such as the T wave, which makes standard reading of the output difficult (or impossible in some cases).
- Printouts: can be printed from the uploaded records using the software
- Cost: less than USD $200 (varies by source)
- Advanced recordings such as sequential 12-lead: yes, via lead wires, but low quality and not really useful for normal 12-lead analyses (see PC-80B for useful, high quality advanced recordings)
- Other aspects and comments: The original versions of the PC-80 device and software have several drawbacks as discussed above (and other drawbacks that I have not bothered to list); these have been more than corrected in subsequent versions of both the device and software, as described for the next device, PC-80B Color, below. The original PC-80 is still useful primarily for persons (including some elderly) wanting something quick and easy for heart rate and a rough look at possible arrhythmias. Because the newer PC-80 versions, particularly the PC-80B Color, are so improved in many ways, the original PC-80 is likely to be discontinued in the near future. If you want one, you might need to get it before current stocks are gone. (Note: there may also be other brands and models, not listed on this website, which are roughly similar to the PC-80 in their simplicity, low cost, and representing early stages of handheld ECG device and software development.)
Source: The PC-80 is still available at http://www.favoriteplus.com/portable-handheld-ecg-ekg-monitors.php and, I think, the manufacturer at http://www.creative-sz.com/Easy-ECG-Monitor/Easy-ECG-Monitor-PC-80A.html. They are likely also available from other online sources.
PC-80B Color (Cardio B Palm [Europe and UK])
(note added 7/30/2016: The Cardio B Palm is a version of PC-80B Color with a slightly different lead-wire/cable connector and available primarily in Europe and the UK, from various companies and in different languages, including user manual available online in different languages. For more information [and the manual] do a browser search for cardio b palm.)
Note (9/25/2016) -- This is one of my "Tester's Choice" devices.
UPDATES: last updated 1/23/2016
(note added 7/30/2016: The PC-80B Color device seems to be most recently marketed mainly under the company name of "Heal Force", e.g., click here , although note that the name situation has become even more muddled!!! ... with several different names and versions -- I will try to figure it out and describe the latest naming explanations later, stay tuned.)
This is the latest version of the PC-80, one of three different handheld ECG devices that I originally reviewed in 2006. At the time, I commented: "It would be nice if one could somehow combine the best of all three [different handheld devices] into a single unit, for example, something like a PC-80 with its size, lighted display, and rocker panel for selecting among menus, but with longer time before auto-shutoff and all of the better features and superior software of the IC." This latest version essentially accomplishes just that, plus having a large, well-lighted (so it works good in the dark) color display, options for different lengths of recording including continuous (and can even be used like a Holter monitor!), new and added features in the software, plus options for USB cable, Bluetooth wireless, or ZigBee for uploading records to the computer.
The PC-80 and its software have gone through many revisions, updates, and improvements, to the point that it is one of the state-of-the-art handheld ECG devices (IF you get the latest version and software [see note at end of the section] and know enough about ECGs to be able to use it).
The latest software is very functional and user friendly/intuitive (once you figure out the correct version to use!, see note at end). The software is sophisticated with many features, including an easy built-in caliper for measuring parts of waveforms. The device has both finger contacts and lead-wire cables.
The PC-80B Color and its software is stand-alone, user-managed, up to the user to communicate with the physician (or be a physician), and the user needs to be somewhat ECG savvy.
Photo of materials received with purchase: shipping package, plastic box with padding, User Manual, Quick Guide, Practical Use guide (not shown in photo), the device with a leather carrying case, software disk, lead-wire cables, and upload cable (for the USB option).
Photo of device startup menu, ready to begin recording with a push of the button.
Recording using the finger/hand contacts (recordings can also be made using the lead-wire cable and adhesive skin electrodes). Screen displays, incidentally, are brighter and better than they appear in these pictures. The display surfaces are reflective and had to be tipped for photos to avoid distracting reflections.
View of a stored ECG record on the device display (including a scale at the bottom indicating the segment being displayed). Display includes background grid markings.
View of section of a list of records (left panel), a recording (normal sinus rhythm, NSR, plus a few PVCs), and menus etc. on the computer screen while using the software. An onscreen caliper allows one to measure various parts of the waveform of a selected beat, as shown, by moving the red and black markers. By right-clicking the box of the selected beat, one can get a zoomed, pop-up box view of that beat, as shown. There are several options and views available (see examples of others below). The software has much utility, is very flexible, and is very intuitive and easy to use with features normally seen only in much more expensive PC-based 12-lead and Holter systems.
Here is a section from a long recording of an episode of atrial fibrillation (afib) plus it includes a PVC (second line, obvious). The sliding page bar at the bottom right allows one to scroll through the whole record. Also see the next figures.
With the "All ECG Wave" tab clicked, one gets the full disclosure of a recording, in this case, a long recording of an afib episode.
Continuing with the afib recording shown above, the afib converted on its own during the course of the recording. By using the "ECG Analysis" tab, which shows heart rate (HR) trend, one can easily see the point of conversion toward the end of the recording when the rate which has been fluctuating around 130 drops to around 100.
And the afib with its conversion is also seen when plotted in another way by clicking on the "Irregular Rhythm Trend" tab, as seen here.
Printed example of a recording (NSR plus some PVCs).
- Physical: 5 x 2 3/4 x 3/4 in (126 x 68 x 20 mm), 4.1 oz (118 g)
- Display screen: color, 2 1/4 x 1 1/2 in (57 x 39 mm)
- Length(s) of recordings: 30 sec for quick measurement with the finger contact electrodes or, if using the lead-wires, continuous, that is, until whenever stopped
- Time to auto-shutdown: 35 sec when there is no operation
- Additional cable-wires for adhesive skin electrode recording: yes
- Internal or memory-card storage capacity: 1200 30-second records or up to 10 hr continuous recording
- Ability to add comments to recording files: yes
- Device menus and ease of use: clear/intuitive and very user friendly
- Software or app menus and ease of use: numerous features and menus, all clear/intuitive and very user friendly
- Printouts: can be sent to selected printer.
- Cost: around $300
- Advanced recordings such as sequential 12-lead: yes, but see note in the next section below regarding the color/letter-coded connections on the lead wires (more on this to be posted later, if and when I get around to it)
Other aspects and comments: State-of-the-art 1-lead (with the possibility of doing sequential other leads), handheld ECG device with very sophisticated but intuitive and easy-to-use software. Both the device and software have gone through numerous revisions and improvements since the original PC-80.
Notes and cautions: This device seems to be available in different versions under a confusing array of similar names related to PC-80B (and Prince 180B, which is similar but not identical ... it is generally sold for less, does not usually include the cable/lead-wires, and does not do continuous recording, only 30 second recordings [even if one gets the cable/lead-wires and uses that for electrode input]; see next device described, below)! The specific one that I reviewed here is referred to by the originating company (Creative Medical, Shenzhen, China) as both PC-80B Color and PC-80B Color Bluetooth although not all of the units called Bluetooth have the wireless Bluetooth connection; some may have and connect to a computer by USB or ZigBee options! There are also [earlier?] versions of PC-80B (and Prince 180B) that have a SD memory card slot but do not have all of the features (as well as I can determine from the descriptions) of the one with the color display and wireless option. This latest one should at least be called PC-80C (which the company also uses in one of the web links for it and some sellers refer to it as PC-80B-C).
The device appears to have evolved and divided into more options and versions faster than its name has been able to keep up! Thus, I urge care and caution that an interested buyer be very careful when purchasing a unit to make sure you carefully specify or shop for and get the specific one you want. The one I tested was PC-80B Color (with emphasis on Color in the name) with USB connection, not wireless or ZigBee.
The software disk that comes with the latest version may also have earlier versions of the software included on the disk with little indication as to which one should be used! I had to use the wireless version of the software even though my specific unit was USB, not wireless! And the user manuals seem to be a mixture of versions. The confusion over software version may have led to poor reviews of the device by other persons on other web sites.
Hopefully the company will clean up the current mess. (I understand they are working on it, based on my reports to them, and Ill eventually be able to delete these notes and cautions.) In the meantime, it remains a mess and you need to be careful so you get exactly the version you want when purchasing and then select the correct software version on the disk when installing.
Color/letter coding of the lead-wire connections: When trying to run (sequential) 12-lead combinations with the lead wires, I got confusing results using the 3 lead-wire connections following the color/letter codes and company recommendations. I also have gotten several inquiries about this issue from persons who bought the PC-80B Color device. As currently supplied, the lead-wires appear to be incorrectly (or at least confusingly) colored/marked. Here's what worked best for me regarding the lead-wire connections:
* red/"R": okay as indicated -- right side or negative electrode
* green/"F": use as the left side or positive electrode
* yellow/"L": use as the neutral or ground (right leg or RL)
(I marked mine with a permanent marker to remind me.) When used that way, they appear to work in the various positions as with sequential 12-lead electrodes. I plan to do more testing along these lines and hope to eventually post the results here.
Sources: See the links to the company at the start of this section. The PC-80B color might become available from Favoriteplus.com after their stock of the original PC-80s are sold out. It is also available from numerous other sources including several US suppliers and is often listed on eBay do a web or eBay search for it. (But, again, make sure you request and get the version you want, and install the "wireless" version of the software even if you don't get an actual wireless unit ... see earlier comments.)
Description under development -- stay tuned/check back later.
Note: The Prince 180B is very similar to the PC-80B Color device, including they both use the same manual and software. However, the Prince 180B, at least in the orange-colored version, which is the one I obtained and tested, does NOT do continuous, Holter-like recording and usually does not come with the cable/lead-wires that the PC-80B Color does. Somewhat (well, VERY) confusingly, there might be a "Prince 180B" version, blue-colored, which I have not obtained and tested, that is like the PC-80B Color which DOES do continuous recording!?!?! ... click here. I'll try to figure it all out and report here later.
UPDATES: (last updated prior to 6/26/2014)
One of the first three handheld devices that I tested and reported. It is still available and still liked by many persons, particularly elderly and those new to such devices who want only the most basic of systems.
ReadMyHeart is a low cost, lightweight recorder designed to be convenient and for use by an average person with minimal knowledge of reading ECGs, that is, for someone who doesn't need to read or monitor the tracings as they are being recorded.
The ECG tracings that appear on the display are NOT the actual ECGs but only simple icons that blink on and off during recording. For a display of the actual ECGs during and after recording, see the InstantCheck and PC-80.
ReadMyHeart software computer-screen view. Excellent ECG traces, very user friendly, and includes individual trace or average measurements.
ReadMyHeart printout. It includes 3 records at a time. (These particular examples represent leads I, II, and III respectively, from using the lead wires in appropriate fashion. That information was included in the records and displays on the computer screen but, because of the glitch in the system's software, described in the characteristics below [and perhaps corrected with recent revisions of software], did not print out on the hard copy such as shown in this figure.)
- Physical: 5 in. x 3 1/4 in. x 3/4 in. (12.5 cm x 8.5 cm x 2.2 cm); weight with batteries approx. 5 oz. (~130 gm)
- Batteries: 2 AAA
- Display screen: record number, date and time, HR, ST, QRS, and noise indicator for records that need to be remeasured; instructions for operation and normal range of values included on inside of lid
- Length(s) of recordings: 15 seconds
- Time to auto-shutdown: after 2 minutes from last time one of the buttons is pressed (about a minute and a half after a recording is started, if no further action taken)
- Additional cable-wires for adhesive skin electrode recording: yes, 2-wire
- Internal or memory-card storage capacity: 30 records
- Ability to add comments to recording files: (Not sure regarding latest version of software, it may have been revised. The version I tested [2006-2008, original version] allowed comments, "notes", to be entered into the record and displayed on the computer screen but then did not print on the printout. That glitch may have been corrected by now; the device is currently available in version 2, but I have not tested that version.)
- Device menus, options, flexibility, and ease of use: simple and straight-forward, limited -- just the buttons shown
- Software or app menus and ease of use: excellent, user-friendly, easy to upload records
- Printouts: can be printed from the uploaded records using the software; printout show 3 records per page, with standard grid and measurements
- Cost: less than USD $200 (varies with source)
- Advanced recordings such as sequential 12-lead: yes, using the lead wires
- Other aspects and comments: Quick start and convenient to record ECGs. Display not lighted and, thus, requires a room light for operation at night, to know when a recording is finished and to see results. The display shows blinking ECG traces during recording, but they are just icons, not the actual tracings being recorded. The software and uploaded ECG recordings are remarkably good, actually excellent, and very useful for reading by a cardiologist or anyone who is familiar with reading ECGs. Records are automatically deleted after upload/transfer to computer.
http://www.dcbiomed.com/webls-en-us/ReadMyHeart:V2.0.html (version 2); also available from several other online sources. (Note that units offered by some of the other sources may be "locked", not allowing full software functionality without a physician's prescription.)
UPDATES: description and photos added to webpage 6/26/2014, company link updated 5/15/2016
For their YouTube introduction to the device, see: http://www.youtube.com/watch?v=PQNK2A61kew&feature=plcp. For other links, see their main page, http://www.rekahealth.com/en/, and scroll down to the various listed categories and links.
The E100 is a small, round ECG recording device. It uploads and communicates between a patient and their personal physician from anywhere in the world where there is an internet or cell phone connection. It is designed specifically for medical use, with security including HIPAA, and marketed primarily to medical centers and physicians wanting a standardized system for assignment to and use by their patients, like event recorders in the past. Anyone, however, can ask their physician about looking into getting it for them. Physicians may also prescribe purchase of the device for a patient, so the patients can own it themselves for long-term use. It is available only by physician order or prescription and involves per-use charges (with a built-in billing and accounting system).
The REKA system is designed for use by the vast majority of medical patients who know or care little about the intricacies of ECG or dealing with the ECG learning curve. It is the fastest and simplest device for recording 1-lead ECGs. One simply picks it up, touches the thumb contacts or connects the optional electrode wires to adhesive skin contacts, pushes the button to start recording, waits for approximately 30 seconds, then uploads the recording(s) directly to their own physician for evaluation ... from home, office, or while traveling locally or from anywhere in the world. The person can reach for it, pick it up, and start recording even in complete darkness. Whenever it is subsequently connected to a smart phone or computer through the appropriate cable, it automatically uploads the latest record(s) and the patients physician is notified.
The E100 operates through either finger contacts or optional lead-wire connections and adhesive skin electrodes. It has no screen display on the recording device, just the starting button which blinks (and the unit beeps) once per second until the recording is finished.
When the physician first assigns a unit to a patient while in the office, the patient can be instructed how to use it. The patient can be shown and allowed to practice with either or both the thumb contacts and lead-wires plus adhesive skin electrodes. The adhesive skin electrodes are useful when a particular patient is unable to get good recordings through the thumbs or if the physician wants recordings from more than one lead. (The lead wires can be sequentially attached to different locations.) Beyond that, the patient needs to know nothing; just pick up the device, record, and plug into whatever upload system is used. If the patient wants or needs to do more with it, they can download the records from a secure site, view them, and add comments (symptoms) to the record. The physician and patient can also communicate results, etc., by email or smart phone.
Unlike the patient, who needs to know little about the system, the medical center and physician(s) have a little learning curve for using the system and learning billing, etc. But that is normal for any medical system. REKA provides good instructions, support, and help, and the cloud-based system is user friendly for whomever logs into it (as medical center, physician, or an individual patient).
Photo of materials received with each ECG recording device: Users Quick Start Guide, soft leather carrying pouch, charger for internal battery (also charges when plugged into a computer via USB), the ECG recording device, upload cables for various smartphones or computer, lead-wire cables (as alternative for thumb contacts), and a supply of adhesive skin electrodes (not in photo) for use with the lead-wire connections.
Photo of device while recording using the thumb contacts. The power button blinks (and the unit beeps) every second for the 30 seconds that the unit is recording, with a long blink at the end to indicate the recording is finished. Recordings can also be done using the optional, alternative lead-wires and adhesive skin electrodes.
When one or more recordings are finished, the unit can then be connected to a smartphone or computer, at which point they are automatically uploaded to the cloud, the patients physician is notified, and the records can be viewed by the patient, physician, or medical center. The physician can interpret the results and get back to the patient.
View (using a computer) of the log-in page (same initial log-in site for all users: patient, doctor, and medical center).
Logged-in view for medical center. Physician view is similar but tailored for physician, as shown further below. Patient view is also somewhat similar but simplified.
Logged-in patient view of a section of their list of recordings.
Patient's screen view of a segment from a selected recording. Comments can be added in the Symptoms box. (Note: the screen views are of better quality, including the lettering, than they appear in these images from segments of the full screen views, which were too large to include on this webpage and still show details. Depending on how the screens are viewed, on smart phones or computers with various sized screens, the material may need to be scrolled or zoomed.)
Logged-in view for physician.
The physician has several tools available for viewing and diagnosing the wave forms, including automatic measurements as shown in the lower part of this view. If the physician does not like the automatic measurement, as shown in the example here for QT interval (bottom two green arrows), he or she can either do it manually with a standard ECG caliper or use the system's built-in tools such as the A-B segment measurement (both the A and B edges of which can be dragged to a desired point), as illustrated for a QT interval (top two green arrows), or use the built-in onscreen electronic caliper (next figure below).
Further example of the view from above but with the caliper checked (green arrow) and ready to start using. (I haven't taken the time to figure out how to properly use the electronic caliper in the REKA system.)
Printed example of the waveform segment from a physician's finished report. This is only part of the report. The full report is longer, involving more on this page than shown plus additional pages that include patient details and further information.
- Physical: 3 1/8 x 2 3/4 x 5/8 in (80 x 70 x 17 mm), essentially round, 3.6 oz (104 g)
- Batteries: internal, rechargeable
- Display screen: (No display screen on recording device, just lighted power button which blinks during recording)
- Length(s) of recordings: 30 sec; NOTE: a 30-day loop recorder is also available (but not yet in the US market and I haven't tested it)
- Time to auto-shutdown: (Always on-standby and ready to record immediately when the power button is pressed; then back to off until the next recording.)
- Additional cable-wires for adhesive skin electrode recording: yes, a 2-wire system
- Internal or memory-card storage capacity: 4,000 records before upload (memory cleared after each upload)
- Ability to add comments to recording files: yes
- Device menus, options, flexibility, and ease of use: easiest possible: just put thumbs on contacts, push button, and recording starts
- Software or app menus and ease of use: uploads done automatically by the app; menus for viewing records are clear/intuitive and very user friendly
- Printouts: pdf reports created by system
- Cost: device cost (part of package to medical center) plus a per-use cost charged to the medical center, reimbursable from insurance, Medicare, etc.
- Advanced recordings such as sequential 12-lead: yes (more on this to be posted later, if and when I get around to it)
- Other aspects and comments: The device and software is designed specifically for medical practices, including appropriate security for HIPAA, etc.
Source:From the company, with representatives in the US and elsewhere around the world. Contact http://www.rekahealth.com/en/
About the Author
James W. Grier is at North Dakota State University, where he has been since 1973. He is currently retired, Emeritus Professor of Biological Sciences. He maintains an office and research lab on campus and stays active in various subjects, including cardiovascular and ECG..
- B.A. 1965 University of Northern Iowa, Cedar Falls, Iowa, Science (Biology) and Education
- M.S. 1968 University of Wisconsin, Madison, Wisconsin, Zoology
- Ph.D.1975 Cornell University, Ithaca, New York, Ecology and Evolutionary Biology with an additional major in Physiology
His interests in biology are very broad, from the molecular to the ecological, particularly in population ecology, anatomy and physiology (particularly cardiovascular and the nervous system), and cover a broad array of organisms, from different groups of invertebrates to vertebrates, including humans. His long-term special interests in particular groups of organisms have included eagles and other birds of prey, fishes, insects, and fossils (particularly ammonites). His teaching background has been similarly diverse, ranging from introductory through upper division, to advanced graduate-level courses with advising of many undergraduate, MS, and PhD students.
As a scientific researcher, he has had long experience doing and teaching about research (including teaching a graduate-level course on biological research for 33 years), across many subjects. Much of that experience and work has involved comparative studies, whether of different animal species and their anatomy/physiology/behavior/ecology or human-made machines and equipment -- the underlying research principles are the same.
Dr. Grier has been involved with the subject of ECGs since 1970 when he took an advanced PhD level physiology course at Cornell University, which included the cardiovascular system, the topic of ECGs, and recording ECGs in lab. He subsequently included the topic of ECGs in his own teaching and when assisting other faculty in human anatomy and physiology, vertebrate and general zoology, and general biology courses since 1973 at North Dakota State University.
He also has had his own personal heart conditions, a variety of irregular heartbeats or arrhythmias, and since the 1980s, has had numerous trips to the ER, clinic, most of the heart tests available, and two ablation procedures, all of which got him involved with a number of physicians, cardiologists, and electrophysiologists (some of whom had been his previous students) and a much deeper understanding of the subject of ECGs.
Between selecting ECG equipment for use in teaching and research labs and wanting his own personal equipment for monitoring and studying his own conditions, he has been using, reviewing, comparing, and studying ECG machines for many years. Because of his accumulated experience and understanding of the subject and ECG machines, he has been requested to became involved in performance testing, review, including as an expert witness for a court case, and even some research and development efforts for various ECG machines.
He has websites (including this one) on the subject of ECGs, initially developed for students at NDSU but also available to other persons external to NDSU, plus one ECG-related publication with colleagues from NASA and the University of Minnesota:
To contact the author, e-mail: firstname.lastname@example.org
Author's web page: James W. Grier
Department of Biological Sciences, NDSU
Appendix: Disclosure/transparency regarding potential conflicts of interest
Outreach service and helping the public is a part of the three-pronged mission at North Dakota State University: teaching-research-service. Service includes both on- and off-campus, including to the general public, to colleagues and other professional persons and organizations, to local/state/federal/international government agencies and non-government organizations, as well as to industry and business. For most of Dr. Grier's life and entire career, he has been and continues to be a student-teacher-researcher-servant at public universities. His nature is to be open and willing to help anyone.
Dr. Grier is not a physician himself ("not that kind of a doctor"), but he has taught large numbers of physicians and other health care professionals -- including introducing them to cardiovascular topics including ECG. He and several of his relatives and friends have had their own heart conditions, which has made the subject personal and gotten him much deeper into the subject than he taught in introductory university courses. He also served as an expert witness doing ECG research for a legal case.
In the process of using and eventually studying ECG machines, he has gotten experience (since 1970) and obtained ECG machines themselves by a variety of ways. Some equipment was obtained through the years by the university for courses in biology and human anatomy/physiology. Many units he purchased personally, for personal use and research, either directly from ECG equipment companies and distributors or on eBay. Several (full 12-lead) ECG machines and supplies used in the legal case were purchased for his comparative research by the plaintiffs-law firm. Some were donated to him by ECG companies/distributors for the purpose of testing their equipment. And in some cases he has been involved in the development of the equipment and systems, either voluntarily or with reimbursement for time and expertise.
For handheld ECG systems covered in this website, his involvement and obtaining of machines has been as shown below.
Most of the devices were sent to the author after learning of his background and experience, often based on reading this or other of his ECG-related websites. The original three and some of the subsequent ones were sent by Favoriteplus.com to help evaluate the devices for them. Most were sent to Dr. Grier at no cost or reduced cost in exchange for his testing and evaluation. Unless indicated otherwise and when significant amounts of time became involved, he has provided the testing and reporting at no charge to the companies, simply in exchange for being able to try out the devices and new technologies.
Several of the systems have involved feedback and reporting of encountered problems to the companies involved, leading to revisions and their current versions/models and ongoing improvements before the device was reported publicly on this webpage. (Note: Dr. Grier usually find problems with systems! Depending on a company's viewpoint, that might be "dangerous" because he often finds unexpected things they didn't know were lurking in the system ... or it might be good and valuable because he has found several problems before they cropped up to bite the company in the marketplace! Even when there are no problems as such, there are usually opportunities for improvement of a product.)
In return, Dr. Grier wants to express appreciation to ALL of the companies involved for giving him the opportunity to try out and learn about the new products and technologies. It's been a mutual, two-way street, hopefully with benefit also to the readers of this webpage and health care everywhere!
AfibAlert -- sent to author for testing and reporting at the developer's/company's request.
AliveCor (three versions of the devices) -- smartphone cases and universal attachment plate sent to author for testing and reporting at the developer's/company's request.
Dimetek (two versions of the devices) ... Micro Ambulatory ECG Recorder, DiCare-m1CP -- sent to author by the company for testing and reporting at request of Favoriteplus.com for their evaluation purposes. The DiCare-m1CC, color version, two units were subsequently sent to the author by the company as an update for further testing and reporting.
ECG Check -- sent to author for testing and reporting at the company's request.
HeartCheck Pen -- sent to author for testing and reporting at the company's request.
InstantCheck -- one of the higher-priced devices sent to author at reduced cost by Favoriteplus.com for testing and reporting, for their evaluation purposes, and in exchange for his input and at his request for a more-advanced device at the time. He subsequently purchased more units from Favoriteplus for class/lab use by the university, paid for by the university, plus additional units from other sources for his own uses and paid for personally.
MD100E -- purchased by the author out of curiosity and following an inquiry from the general public.
PC-80 -- sent to author by Favoriteplus.com for testing and reporting, for their evaluation purposes.
PC-80B Color -- sent to author by the company for testing and reporting at request of Favoriteplus.com for their evaluation purposes.
Prince 180B -- purchased by the author to compare with the PC-80B Color.
(printing) ECG/EKG-80A -- purchased by the author, based on an inquiry by a reader who was wondering about it.
ReadMyHeart -- sent to author by Favoriteplus.com for testing and reporting, for their evaluation purposes.
REKA E100 -- (several units) sent to author for testing, reporting, and help with identifying needed improvements at the developer's/company's request, following a visit to Dr. Grier's lab by two of the company's personnel. Dr. Grier spent extensive time with the developers and engineers regarding both the device itself and its cloud-based system, to help correct initial problems and make improvements, for which he received two honoraria and a per diem for a meeting that he participated in, but no salary or contract funding.