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Guide to DIY Heart Rate Monitors (HRMs) & Handheld ECG Monitors (Part I)

Consumer Heart Rate Monitors (HRMs) and Handheld ECG monitors

by Steve S. Ryan, PhD, Last updated: February 16, 2019

Atrial Fibrillation patients sometimes want to monitor their heart rate and pulse when exercising or when performing physically demanding activities (e.g. mowing the lawn, climbing stairs, loading and unloading equipment, etc.). A consumer ‘DIY” heart rate  monitor (HRM) or Handheld ECG monitor may meet this need.

Not to be Confused with Optical Fitness Wristbands

The HRM sensors/monitors in this article work by being in contact with the skin.

Optical LEDs on inside of HRM wristband

Don’t confuse these with fitness bands like Fitbit or running/sport watches that use an optical sensor to shine a light on your skin illuminating your capillaries to measure your pulse (most accurate for a resting heart). Optical sensor wristbands are not accurate enough for A-Fib patients. (For more, see my article: When Tracking Your Heart: Is a Wrist-Worn Heart Rate Monitor Just as Good as a Chest Strap Monitor?)

To read a comparison test by Tom’s Guide, see Who Has The Most Accurate Heart Rate Monitor? It’s All About Accuracy (Spoiler alert: top rated was a Polar chestband). 

 Consumer HRMS

We’ve sorted through the plethora of Heart Rate Monitor products and brands and have recommended products in a range of prices and with a range of features.

Consumer, DIY or ‘Sport’ Heart Rate Monitors (HRMs) are designed for runners and other recreational athletes to collect helpful data for lifestyle changes and training goals (pace, distance, heart rate, pulse, etc.).

Heartbeat sensors are either attached to a chest band or built-in to wearable technology and paired with a wireless link to a wrist watch or app-enabled smartphone. HRMs are available from sporting goods stores and online from and other sites.

For our quick start list go to Steve’s Top Picks: DIY Heart Rate Monitors for A-Fib Patients on

The Gold Standard brand for HRMs is Polar. (The first EKG accurate wireless heart rate monitor was invented by Polar back in 1977 as a training tool for the Finnish National Cross Country Ski Team.) You can view the extensive range of Polar products at their website,

Other companies offering consumer ‘Sport’ Heart Rate Monitors include Timex, Garmin, Acumen, Nike, and Cardiosport plus a host of others if you shop around.

To learn how HRMs work, recording capabilities and how they can help A-Fib patients monitor their heart rate, see Part 2 of this article: DIY Heart Rate Monitors: How They Work For A-Fib Patients (Part II).

We’ve Done the Heavy Lifting for You

To help you sort through their extensive offerings, I narrowed down the choices to a few basic and advanced wristwatch models, Bluetooth models, and the newer wearable technology each in an array of price points.

Polar FT1 HRM with chest band at

Polar FT1 HRM with chest band

Wrist Watch Monitors with Chest Band

Consisting of two components, these HRMs use sensors attached to a heart rate strap that wraps around the chest and sends a wireless signal to the wrist unit. Some models connect with compatible gym equipment, $65–$400. (More features = higher prices.) A few to consider:

♥  Polar FT1 Heart Rate Monitor Watch (the LARGEST numbers for heart rate I’ve found)
♥  Polar FT7 Fitness Heart Rate Monitor Watch
Polar RS300X Heart Rate Monitor
♥  Polar V800 GPS Sports Watch & Activity Tracker

Polar H10 Bluetooth Heart Rate Monitor with smartphone app

Polar H10 Bluetooth Heart Rate Monitor with smartphone app

Bluetooth App-Enabled Sensors for Smartphones

Smartphones are ubiquitous. For many, their smartphone is an essential part of their standard daily gear. So, it’s no wonder that a smartphone can replace the heart rate wristwatch signal receiver. ($20–$75)

Today, you can use Bluetooth technology to send the signal from your heart rate sensor to a receiver in an app-enabled smartphone. Here are a couple to consider:

♥  Polar H7 Bluetooth Heart Rate Sensor & Chest Strap
♥  Polar H10 Heart Rate Monitor, Bluetooth HRM Chest Strap
♥  Jarv Premium Bluetooth® 4.0 Smart Heart Rate Monitor for Android Devices

Wearable Technology with Wireless Sensors

Wearable technology from Sensoria

“Wearable technology” offers a new option for those who find a chest strap uncomfortable or chafing. Instead of the chest band these workout clothes have sensors built-in. Starting at $75.

Note: Unless sold as a set, you still need a Heart Rate sensor to snap on to the front of the garment and a signal receiver—a wrist watch monitor or app-enabled smartphone. (if you are replacing a chest band, you may be able to reuse the sensor.)

♥  Sensoria Fitness Men’s T-Shirt with standard sensor snaps (no heart rate sensor)
♥  Sensoria Fitness Men’s T-Shirt with sensor snaps and Heart Rate Sensor
♥  Sensoria Fitness Sports Bra with standard sensor snaps (no heart rate sensor)
♥  Polar H10 Bluetooth Heart Rate Sensor (no chest band) link using account ID afiin-20

When you shop for DIY HRMs, use the portal link to and your purchases automatically generate a small commission (at no extra cost to you) which we apply to the publishing costs of Bookmark this link. Use it every time.

 Real-Time ECG Monitors

This category of consumer monitors has been growing of late with some models having only limited track records. Going beyond just monitoring your heart rate, these units capture data and display it as an ECG (EKG) in real time.

With prices ranging from $99 to $300 (and up), you need to consider size (portability) and ease of use compared to price. Again, I’ve selected a few handheld ECG monitors from the plethora of choices.

Kardia Heart Monitor by AliveCor

AliveCor Kardia review at

L-R: Kardia attached to back of smartphone, Kardia unit and ECG tracing on cell app.

The Kardia monitor is a FDA-approved device that works with your smartphone and allows you to take an ECG recording of your heart from the comfort of your home, office, or anywhere.

It’s very straight forward to use the device. After you download the app to your smartphone, open and click on “Record Now”; then press your fingers to the device. There are three ways to hold the Kardia: attached to the back of your smartphone; grasping with finger tips; pressing on a flat surface.

AliveCor with tablet at

Using Kardia with tablet

The Kardia consists of two parts. There is the device itself, a small, wireless component that attaches or sits in close proximity to a cell phone or tablet. It syncs to the second component, a smartphone app.

Read our the full article Update: AliveCor Kardia Review by Travis Van Slooten, the publisher of and a former A-Fib patient.

GO PREMIUM: Enjoy unlimited cloud storage of all your EKG recordings, plus mailed monthly reports and much more for just $9.99/mo.

VIDEO: Best video footage I could find of the Kardia app screen. Shows actual capturing of the ECG signal with an inset image showing the users hand positions on the Kardia device. (Start watching at 2:30 min.; in Spanish)

Cost: $99 on Amazon (plus monthly fee).

CONTEC Handheld Portable ECG Heart Rate Monitor PM10/EMAY Ltd EMG-10

The Contec PM10 is also sold as the EMAY Ltd EMG-10. The PM10 is a small 4 oz. unit that can track a single channel ECG waveform. You can observe the 10-second scan live, then download the recordings (up to 30) to your computer or smartphone for review and print to share with your doctor. It claims to detect up to 12 cardiac conditions. I don’t have A-Fib anymore (thank goodness), so I wasn’t able to test while in A-Fib.

The Contec PM10 is easy to use and carry in a pocket or handbag for scans on the go. Or leave with your laptop for periodic checks. While you can observe the ECG scan live on the screen, there’s no review screen. You must download the scan to review it or print it.

Review screen with ECG and data

A Contec review on by Ron Crist noted there’s no hidden fees like other popular devices (i.e., monthly fee for Kardia Heart Monitor by AliveCor).

Observing the live ECG tracing may be enough for most A-Fib patients who just want a quick check of their heart beat and heart rate. Read my full review of the Contec PM010 for how to scan and download scans.

Cost: Contec PM10 and EMAY EMG-10 are about $79 on Amazon.

Heal Force PC-80A/PC-80B/Prince180B ECG Monitor

Heal Force PC-80A portable EKG monitor -

Heal Force PC-80A

The PC-80/180B is a state-of-the-art 1-lead, handheld ECG device with very sophisticated but intuitive and easy-to-use software. The user does need to be somewhat ECG savvy.

It has a large, well-lighted color display with options for different lengths of recording including continuous and can even be used like a Holter monitor! (Be sure to get the right model if you want this feature.) It comes with both finger contacts (choose palm, chest or leg measurement) and lead-wire cables. To upload to your computer, you have options of USB cable or Bluetooth wireless.

FDA-approved. Marketed by several different companies: Heal Force PC-80B, Creative Easy ECG Monitor PC-80B and Cardio-B Palm ECG (with various versions). Read more details on the PC-80B at the Heal Force website.

Cost: About $150 on Amazon.

Heal Force 180D Color Portable ECG Monitor With 3-Lead Cables

180D using 3-ECG lead Cables

180D using 3-lead Cables

You might want to step up to the Heal Force model with 3-lead cables, the 180D Color Portable ECG Monitor. It’s also FDA-approved.

Heal Force 180D EKG portable monitor

3-Lead Heal Force 180D

Quick measurement by built-in metal electrodes, or 3 external lead wires. Equipped with more advanced functions and features than the Prince 180-B (above).

Like the PC-80A/PC-80B/Prince180B ECG Monitor, it’s small, lightweight, and easy to carry. ECG waveform and interpretation of results are displayed clearly on a color dot-matrix LCD screen.

High capacity built-in memory, up to 30 hours ECG waveform storage for single channel continuous measurement. Download results via USB port to PC or use a thumb drive and take to your doctor.

Unfortunately, the instruction manual is clearly translated from Chinese. Learn more about the Heal Force 180D at Heal Force site.

Cost: about $180.

BodiMetrics Performance Monitor

BodiMetrics Performance Monitor review at

BodiMetrics Performance Monitor

The BodiMetrics Performance Monitor captures and displays an actual ECG tracing and can store up to 100 records. All information is transmitted via Bluetooth to the BodiMetrics app on your iOS or Android device.

Startup screen for multi-function health monitor

More than just for ECGs. The BodiMetrics Performance Monitor is a multi-function health monitor.

This FDA approved devise will collect blood oxygenation levels (SpO2), body temperature, and systolic blood pressure. Capture steps, stride, calorie burn and Target Heart Rate Zone for optimal work outs. Set goals with daily reminders and medication alerts. Provides audible and visual usage instruction. Palm-size, slips into your pocket or purse.

VIDEO: watch a 1:09 min video of the BodiMetrics in actual use including audible instructions. Several models. Also marketed as the Viatomtech CheckMe Monitor (Lite or Pro).

Cost: starts around $300 on Amazon.

Handheld 12-Lead ECG Monitor CMS-80A (FaceLake or Contec Medical Systems)

Facelake Hand-Held Single Channel ECG, ECG 80A Link

Facelake Hand-Held ECG 80A

Review by Ed Webb

Note: Read about how Tom Burt used the CMS-80A in his Personal Experience story. He writes, “This came in very handy as a way to inform my EP when I did get out of rhythm. This was done by faxing him a strip of the printout.”

The Contec CMS-80A is a single channel, 12 lead monitor which can provide data via one of three ways: on the unit display, via the thermal printer internal to the unit, or via a USB connection to a PC. The printout from the unit offers the easiest and most accurate means to view lead output. While you can view lead output on the display, you will find that it is not to the same level of detail as the printout.

Like most normal ECG monitors, 10 electrodes are attached to the body as follows: 6 suction cup leads to the chest and 4 alligator clip leads to the arms and legs. The unit does not rely on the normal press-on style contacts but rather takes a simpler approach with its reusable contacts. Personally, I [Ed Webb] wasn’t too impressed with the suction cup style contacts as they feel funny and leave a mark as if you had been attacked by an octopus. But they seemed to do the job. The alligator clips, while funky, were quick and easy to attach.

Facelake Hand-Held Single Channel ECG, ECG 80A Link

Thermal paper in Facelake Hand-Held Single Channel ECG, ECG 80A – link

The waveforms presented are not what you would expect from an ECG in your cardiologist’s office, but they can provide the simple basics to make a quick determination whether you are in A-Fib. In particular, by examining the output from Lead II, or perhaps Lead aVF, you can quickly observe the absence of a P wave—one sign that you may be in A-Fib. Additionally, examining R-R intervals and whether they are uniformly spaced can be another means to aid in that determination.

From a practical perspective, it could be that you choose to only attach the alligator leads to your arms and legs and forego using the chest leads. You will obviously not have the data from the chest leads (V1 to V6), but that information may not be needed for A-Fib purposes.

Thermal printout from the Handheld ECG Monitor CMS-80A ECG

FDA-approved. For more info and to see what the display looks like, visit the Contec product information page. The CMS-80A (ECG-80A) can be purchased directly from and other locations online

Cost: $299-$380

 Remote Smart Monitors

MyPulse Provides Email or Text Message Alerts

Are you worried about a relative in A-Fib whom you can’t be with all the time? There is a long range heart monitor your relative can use which will transmit to you if he/she goes into A-Fib or exceeds a normal heart rate.

MyPulse by Smart Monitors link

MyPulse (home model) by Smart Monitors

If you have a need to monitor a relative’s or friend’s heart rate or want to know if your relative or friend has gone into A-Fib, MyPulse by Smart Monitors, Inc. has a solution for you. This is a practical alternative to the expense of a medical monitoring service if you are just interested in simple heart rate data. Obviously, if there are medical concerns relative to the heart arrhythmia, you should find an appropriate medical monitoring solution in concert with the patient’s cardiologist. But if you are looking for an alternative to a medical service, read on.

Most heart rate monitors rely on a chest strap which transmits heart rate data to a wristwatch, bike computer or even smart phone worn or carried by the individual. The MyPulse Long Range Monitor is no different, but instead of the watch to read the data, it has a small Repeater device which is carried by the individual (or located within 3’ of the person wearing the chest strap). The Repeater transmits the data to a Receiver which is connected to a PC/notebook via a USB port.

The combination of Repeater/Receiver gives the wearer a practical range of throughout the house (the kind of range you would expect to see on a Wi-Fi network for instance) and up to 1000’ if the Receiver has an unobstructed view of the Repeater. The MyPulse application runs on the PC and provides a graphic display of real time heart rate data.

Bluetooth mid range/global range monitor

This is the cool part: the software can be configured to provide alerts via email or text message to multiple recipients (such as a caregiver) if a preset limit is exceeded (such as might occur if the wearer goes into A-Fib). For you more tech savvy people, if you want to run a PC mirror app on your smart phone, you can view the real time heart rate data at anytime, anywhere, and not have to worry about waiting for an alert if a limit is exceeded.

All in all, this is a remote heart rate monitor solution that provides a low cost alternative to a medical monitoring service, if you and your cardiologist determine you don’t need such a service. Check out the MyPulse by Smart Monitor, Inc. on their website and from (using our portal link).

Cost: Bluetooth models $149 – $495

 In-Depth Report Of ECG Monitors

Report: Comparison of Handheld, 1-Lead/Channel ECG/EKG Recorders

An extensive online resource for anyone considering one of the newer hand-held ECG monitors. “Comparison of handheld, 1-Lead/Channel ECG / EKG recorders” is a personal project by James W. Grier, Emeritus Professor of Biological Sciences, North Dakota State University.

The webpage is nothing fancy, but his report is extremely detailed and extensive (last updated Dec. 2017), with multiple photos of each step of testing and multiple print outs of the results. A most thorough report. Go to “Comparison of handheld, 1-Lead/Channel ECG / EKG recorders

Resources for this article
Prospero, Mike. Who Has The Most Accurate Heart Rate Monitor? It’s All About Accuracy. Tom’s Guide, Jun 1, 2016. URL:,review-2885.html

Grier, J. W. Report: Comparison of Handheld, 1-lead/Channel ECG/EKG Recorders. Latest revision: September 26, 2016. URL:

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f you find any errors on this page, email us. Y Last updated: Saturday, February 16, 2019

FIRM (Focal Impulse and Rotor Modulation) for Catheter Ablation of A-Fib by Dr. Narayan of UC San Diego

red-heart-negative 150 pix by 96 resby Steve S. Ryan, PhD

I have received several emails asking why I don’t write about Dr. Sanjiy M. Narayan’s studies. I must admit to not understanding some aspects of FIRM and was hoping further information would make things clearer.

Ablating focal beats and electrical rotors, or as Dr. Narayan describes them, “localized areas of electrical activity” is nothing new. (See 2011 Boston A-Fib Symposium, Using CFAEs in Ablating Persistent A-Fib, and 2009 Boston A-Fib Symposium, CFAEs vs. Dominant Frequency) Dr. Narayan’s FIRM procedure uses the largest 64-pole standard basket catheter to do the mapping and uses “monophasic action potentials” (MAPs) catheter mapping to physiologically identify the A-Fib generating spots in the heart.

Proprietary, Patented Algorithm

What is new is the proprietary, patented algorithm Dr. Narayan uses to display the optical images and movies of the activation. (A description of the signal processing Dr. Narayan uses is found in the article “Computational Mapping Identifies Localized Mechanisms for Ablation of Atrial Fibrillation.”) Topera Medical, which licensed this algorithmic-based mapping system, calls it RhythmView.

This author doesn’t understand how Dr. Narayan’s proprietary system differs from other non-proprietary systems using basket catheters to map focal beats and rotors, with the possible exception that he uses the largest basket catheter with a wide field of view to be able to map almost an entire atria at one time.

Targets Rotors and Focal Beats Before Any Other Ablation Sites

After ablating rotors and focal sources found by his FIRM mapping system, Dr. Narayan also ablates the pulmonary veins utilizing wide area circumferential ablation—similar to what is currently done in most A-Fib centers.

Dr. Narayan targets ablation at rotors and focal beats before any other ablation sites, including the pulmonary veins. “Ablation at only rotors and focal sources revealed by our mapping approach (without pulmonary vein isolation) terminated AF predominantly to sinus rhythm in seconds to minutes.”

According to Dr. Narayan, “patients undergoing this targeted ablation (FIRM) experienced a superior rate of AF elimination in the long-term compared to patients undergoing traditional ablation procedures focusing on trigger mechanisms near the pulmonary veins.” Yet, after ablating rotors and focal sources found by his FIRM mapping system, Dr. Narayan also ablates the pulmonary veins utilizing wide area circumferential ablation—similar to what is currently done in most A-Fib centers.

Others Start By Ablating the PVI First

Dr. Narayan’s approach differs from standard operating procedure in almost all centers which start with ablating or isolating the pulmonary vein openings first before moving to other areas.

To this author, Dr. Narayan’s approach doesn’t make intuitive sense. If the pulmonary veins are still firing when mapping is done of the rest of the atrium, wouldn’t these PV signals interfere with or confuse the mapping? In most paroxysmal A-Fib patients, isolating the pulmonary veins is often all that’s needed to eliminate A-Fib (these patients often don’t have any other sources of A-Fib signals outside of the pulmonary veins).

Dr. Narayan found that patients with persistent A-Fib had more sources than those with paroxysmal A-Fib, though these sources were few in number—only about 2 for both atria. This is in contrast to previous studies which have found a greater number of A-Fib producing spots, especially in persistent A-Fib patients.

Dr. Narayan found that almost one-quarter of A-Fib sources come from the right atrium.

Contrasts with Established Protocols

For persistent A-Fib patients Dr. Narayan makes a left atrial roof line ablation, and for those with typical atrial flutter he makes a cavotricuspid isthmus ablation. No other ablation is performed even for persistent A-Fib. This contrasts with established protocols for ablating persistent A-Fib. (See 2008 Boston A-Fib Symposium, Stepwise Approaches in Ablating Chronic A-Fib.)

Trial Results

PRECISE-PAF trial results of FIRM ablation for atrial fibrillation without pulmonary vein isolation (PVI). This was a multi-center trial performed at nine centers with 33 patients showed a 67% termination of A-Fib, with another 17% showing a greater than 10% slowing in their A-Fib.

This is a relatively few number of patients.

EDITOR’S COMMENTS: Perhaps the most important innovation of FIRM is the ability to map and ablate rotors and focal beats in “seconds to minutes.”
Right now doctors doing ablations on patients with persistent A-Fib spend a great deal of time and effort tracking down and ablating rotors and focal sources of A-Fib. If Dr. Narayan’s FIRM system makes this part of the ablation procedure easier, faster and more accurate, this would be a major medical breakthrough for A-Fib patients and doctors. 
(The author admits to not understanding how the FIRM system works compared to other systems using basket mapping catheters.)
But one can question the validity and accuracy of the FIRM system, since it typically finds only about 2 A-Fib sources in each atria.
It’s hard to compare Dr. Narayan’s results or to say his approach is superior to standard Pulmonary Vein Isolation. Most experienced A-Fib centers achieve around a 67% success rate as Dr. Narayan does. Though Dr. Narayan first ablates rotors and focal sources in the left atrium, he does later ablate the Pulmonary Veins like almost all other centers.
(It probably makes more sense to first ablate the PVs, then use the FIRM system to track down any A-Fib
A second important innovation of Dr. Narayan’s FIRM mapping system is the finding that one-quarter of A-Fib signals come from the right atrium. If future trials confirm this finding, doctors might have to change their ablation procedures and direct more attention to the right atrium.
References for this Article
• Narayan, S. M. et al. “Computational Mapping Identifies Localized Mechanisms for Ablation of Atrial Fibrillation.” PloS One, 2012; 7(9): e46034, published online 2012 September 26. doi: 10.1371.journal.pone.0046034

• Narayan, S. M. et al. “Clinical Mapping Approach to Diagnose Electrical Rotors and Focal Impulse Sources for Human Atrial Fibrillation.” Journal of Cardiovascular Electrophysiology. 2012 May;23(5): 447-54 doi: 10.1111/j.1540-8167.2012.02332;

• Haimovitch, Larry “New AF mapping technology data may finally silence the skeptics.” Haimovitch Medical Technology Consultants May 15, 2012.

Posted February 2013

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Last updated: Wednesday, September 2, 2015

The CHADS2 & CHA2DS-VASc Stroke-Risk Grading Systems

Stroke-Risk Grading Systems

Stroke-Risk Grading Systems

By Steve S. Ryan, PhD, Updated Nov 2014

In the US, doctors use what is called a CHADS2 stroke-risk grading system to help estimate the risk of stroke in patients with atrial fibrillation. A high CHADS2 score corresponds to a greater risk of stroke, while a low CHADS2 score corresponds to a lower risk of stroke. The CHADS2 score is simple and has been validated by many studies.

The patient’s stroke risk, i.e., their CHADS2 score, is estimated by adding together the points that correspond to the patient’s conditions.

“C” Congestive Heart Failure Score = 1

“H” Hypertension Score = 1

“A” Age over 75 Score = 1

“D” Diabetes Score = 1

“S2” Previous Stroke or TIA Score = 2

 A CHADS2 score of 2 or over would indicate someone should be on a blood thinner such as warfarin.

The CHADS2 score has been superseded in clinical use by the CHA2DS2-VASc score that is designed to give a better stratification of low-risk patients. It utilizes the same 5 major risk factors considered by CHADS2 but assigns a score of ‘2’ for patients older than 75 years, and adds 3 new risk factors: a history of vascular disease, age 65-74 years, and female sex which increase stroke risk. But according to the original study, “there was no statistically significant difference found between the CHA2DS2-VASc and CHADS2 risk stratification schema in predicting TE events”.

A-Fib Stroke Risk Calculators

CHAD2DS2VAC Medium 100 pix at 96 resUse this link to calculate your A-Fib stroke risk using the CHADS2 Calculator
Use this link to calculate your A-Fib stroke risk using the CHA2DS2-VASc Calculator

Classification of CHADS2 vs CHA2DS-VASc

In both scoring systems, a score of 0 is “low” risk of stroke, 1 is “moderate”, and any score above 1 is a “high” risk. The CHA2DS2-VASc system has three more variables and therefore will classify a greater number of patients into a high-risk group.

Editor’s comment: There is some controversy about the increased stroke risk for females. See articles on Dr. John M’s blog post and Aging Well magazine.
See also our article: Women in A-Fib Not at Greater Risk of Stroke, and The New CHA2DS2-VASc Guidelines and the Risks of Life-Long Anticoagulation Therapy.

References for this article

Hwang, Calvin. CHA2DS2-VASc Score for Atrial Fibrillation Stroke Risk. Last accessed 6/15/15.

Lip, GYH et al. Refining Clinical Risk Stratification for Predicting Stroke and Thromboembolism in Atrial Fibrillation Using a Novel Risk Factor-Based Approach: The Euro Heart Survey on Atrial Fibrillation. Thromboembolism. February 2010. Last accessed 6/15/15.

Gage BF, Waterman AD, Shannon W, Boechler M, Rich MW, Radford MJ (2001). Validation of clinical classification schemes for predicting stroke: results from the National Registry of Atrial Fibrillation. JAMA 285 (22): 2864–70. doi:10.1001/jama.285.22.2864. PMID 11401607.

Gage BF, van Walraven C, Pearce L, et al. (2004). Selecting patients with atrial fibrillation for anticoagulation: stroke risk stratification in patients taking aspirin. Circulation 110 (16): 2287–92. doi:10.1161/01.CIR.0000145172.55640.93. PMID 15477396.

Atrial Fibrillation is a Major Risk Factor for Stroke. Thrombosis Adviser website. Last accessed November 15, 2014. URL:

Mandrola J. Female gender and stroke risk in atrial fibrillation: Know your CHA2DS2-VASc Score. Last accessed Jan 10, 2013 URL:

Older Women With Atrial Fibrillation at 20% Greater Risk of Stroke, Aging Well. Last accessed Jan 10, 2013 URL:

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Last updated: Thursday, September 3, 2015

Diagnostic Tests

Diagnostic Tests for Atrial Fibrillation -, A-fib, afib, a fib

Diagnostic Tests for Atrial Fibrillation

Diagnostic Tests for Atrial Fibrillation

Doctors have several technologies and diagnostic tests to aid them in evaluating your A-Fib. Your doctor will likely make use of several from this list.

 Blood Tests

Blood tests check the level of thyroid hormone, the balance of your body’s electrolytes (i.e. potassium, magnesium, calcium, sodium, etc.), look for signs of infection, measure blood oxygen levels and hormone levels, and other possible indicators of an underlying cause of Atrial Fibrillation.

Blood tests can also reveal whether a patient has anemia or problems with kidney function, which could complicate Atrial Fibrillation.


An Electrocardiogram (ECG or EKG) is a simple, painless test that uses up to twelve sensors attached to your body to create a graphical representation of the electrical activity of your heart. The standard ECG records for only a few seconds.

It can only detect an A-Fib episode if it happens during the test. For a longer period of time, a portable ECG monitor is used. 

VIDEO 1: EKG of heart in A-Fib

VIDEO 1:  EKG of Heart in Atrial Fibrillation

Graphic display of actual heart in Atrial Fibrillation. How it could look to your doctor on an EKG/ECG monitor; (Your EKG may look different, but will be fast and erratic). Includes display of the changing heartbeat rate in the lower left. Go to video->

NOTE: For an in depth explanation of the ECG/EKG waveform signal and how to “read” an ECG tracing, see my report Understanding the EKG Signal.

 Holter and Event Monitors

Those with occasional A-Fib (Paroxysmal) may not experience an A-Fib episode during their ECG. So, doctors have other means of capturing your A-Fib data.

Holter Monitors

A Holter Monitor is a small, portable recorder that’s clipped to a belt, kept in a pocket, or hung around your neck and worn during your normal daily activities. The leads from the Holter Monitor attach to your body like the sensors of an ECG. The Holter Monitor records your heart’s electrical activity for a full 24–48 hour period in hopes of capturing data during an A-Fib attack.

Patient-Activated and Event Monitors

An Event Monitor is similar to a Holter Monitor, but records data only when activated by the patient. Pressing a button saves several minutes of data preceding and several minutes afterward.

Some event monitors start automatically when they sense abnormal heart rhythms. You might wear an event monitor for one to two months.

VIDEO 2: Zio Patch in use.

VIDEO 2: The Zio® Patch (iRhythm): Single-Use Ambulatory Cardiac Monitor

Updated 2-07-2018: The Zio® Patch cardiac monitor (iRhythm) looks similar to a 2-by-5-inch adhesive bandage and sticks to a patient’s chest. Learn about this single-use ambulatory, continuously cardiac monitor that records for up to 14 days with no need to removal during exercise, sleeping or bathing. (2:04 min.) Go to video->

Implantable Monitors

Medtronic Reveal LINQ ICM

An Implantable Monitor is a type of event monitor without wires that’s inserted under the skin through a small incision. It’s used for patients with infrequent, unexplained fainting or passing-out when other tests have not found the cause. The implantable monitor is used for up to a year or more.

For a first-hand account with a Medtronic Reveal LINQ implantable monitor, see Steve’s September 2018 post: Has My A-Fib Returned? I Get an Insertable Wireless Monitor to Find Out

NOTE: For an in depth look at ECG monitors (including DIY/consumer heart rate monitors), see my report A Primer: Ambulatory Heart Rhythm Monitors.

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 Exercise Stress Test

During a stress test, you walk (or jog) on a treadmill while an ECG records your heart’s activity. This is often combined with an echocardiogram before and after the stress test to view and measure heart functions. 

 Tilt-Table Test

When the cause of dizziness, fainting or light-headedness isn’t detected by ECG or the Holter/event monitor, a tilt-table test may be performed. The table tilts the patient upright at a 70–80 degree angle for 30–45 minutes. As you are moved from a horizontal to an upright position, your blood pressure, heart rate and heart rhythm are monitored.

VIDEO: Patient introduction to the tilt table test. New York Cardiovascular Associates website,

VIDEO 3: The tilt table test.

VIDEO 3: Tilt table test: Patient introduction to the tilt table test. Description of the test as we see a technician take a patient through a tilt table test. (1:15) Video posted on the New York Cardiovascular Associates website. Go to video->

 Electrophysiology Study

An electrophysiology study is a special catheterization test to examine the electrical activity inside your heart. It’s used to determine if and why the rhythm is abnormal. An electrophysiologist (EP) inserts several electrode catheters through the veins in your groin. Real-time images or moving X-rays (fluoroscopy) help guide the catheters into the heart.

Once in place, the EP uses the catheters (and perhaps arrhythmia drugs) to artificially stimulate your arrhythmia. By recording data from strategic locations within the heart, most kinds of cardiac arrhythmias can be fully documented.

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 Imaging Technologies

Echocardiography (Cardiac Ultrasound)

An Echocardiograph uses ultrasound waves to create a moving picture of your heart. As special sound waves are bounced off the structures of your heart, a computer converts them into pictures. These images show the size and shape of your heart and how well your heart chambers and valves are working.

Your cardiologist can locate areas of poor blood flow and previous damage, and areas that are fibrillating or not contracting properly as well as identify and measure deformations of heart chambers and thickening of heart walls.

Transesophageal Echocardiology, TEE - Atrial Fibrillation test, A-fib, afib, a fib

Screen image: TEE

Transesophageal Echocardiography (TEE)

In this test, a tube with an ultrasound device is passed down through your esophagus. A clear image is captured of the heart muscle and other parts of the heart. As ultrasound waves are directed into the heart, the reflected sound waves are converted into pictures.

The TEE is often administered just before an ablation to look for blood clots in your atria. If blood clots are found, anticoagulants are prescribed to dissolve them.

Computerized Tomography (CT) or Magnetic Resonance Imaging (MRI)

‘Cardiac CT’ uses an X-ray machine and a computer for detailed images of the heart and to make three-dimensional (3D) pictures of your heart and chest.

The electrophysiologist uses them to perform catheter ablations inside the heart. A ‘cardiac MRI’ uses radio waves, magnets and a computer to create snapshots and video of your beating heart and can measure the amount of fibrosis (which can be a factor in A-Fib).

Chest X-Ray

X-ray images help your doctor see the condition of your lungs and heart such as fluid buildup in the lungs, an enlarged heart, and other complications of A-Fib.


There are several tests your doctor may use to evaluate your A-Fib. A basic understanding of these tests helps you ask informed questions and discuss test results.

 Additional Readings

• Sleep Apnea: Home Testing Now Available
• A Primer: Ambulatory Heart Rhythm Monitors
• Consumer (DIY) Heart Rate Monitors
• Understanding the EKG Signal
• The CHADS2 Stroke-Risk Grading System

Last updated: Saturday, February 16, 2019

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A Primer: Ambulatory Heart Rhythm Monitors

ECG pads positioned

Source: patient education brochure

By Steve S. Ryan, PhD, Last updated: February 16, 2019

In order to make a diagnosis of an arrhythmia, some form of electrocardiographic recording (i.e. ECG/EKG) must be made at the time the arrhythmia is occurring.

If an arrhythmia becomes persistent and is present day-in and day-out, as often is the case for A-Fib, the diagnosis is quite easy with a routine ECG done in the physician’s office.

The challenge is when an arrhythmia occurs intermittently what doctors call “paroxysmal ” (on and off) or is self-limiting. In this case, when an ECG is performed in between A-Fib episodes, the ECG will appear completely normal. To circumvent this problem, one would go to the next level of evaluation with a long-term monitor.

Example: ECG tracing of Atrial Fibrillation shows tiny, irregular and erractic “fibrillation” waves between heart beats..

Long-term monitors

When your arrhythmia is intermittent, your doctor may have you wear a mobile type of heart rhythm monitor to capture the electrical activity of your heart.

Long-term monitors basically are ECG recorders that patients can take with them (ambulatory). They fall into two major categories: continuous recording (Holter) and intermittent recording (Event).

The Holter Monitor

Mortara H12+ Continuous 12-lead Holter recorder

Mortora H12+ Continuous 12-lead Holter recorder

A Holter Monitor (named after Dr. Norman Holter, go figure) records continuously the ECG of a patient, usually for 24 – 48 hours. More modern Holter units record onto digital flash memory devices. The data are uploaded into a computer where software analyzes the input, counting ECG complexes, calculating summary statistics such as average heart rate, minimum and maximum heart rate, and finding candidate areas in the recording worthy of further study.

The advantage of a Holter is that every single heartbeat during that day is recorded and can be analyzed. The disadvantage is that if an arrhythmia did not happen on that particular day, the Holter data would not be useful.

The Event Monitor

Cardionet wireless event monitor

Cardionet wireless event monitor

An Event Monitor, on the other hand, is a long-term monitor that can be used for up to 30 days or longer. The advantage is that the longer the recording period, the better chance of “catching” an intermittent arrhythmia. The disadvantage is that an Event Monitor must be activated by the patient and downloaded telephonically, a task that requires a certain amount of manual dexterity and may be difficult for some patients.

Some event monitors are patient activated when having an episode and save the last several minutes of data; others detect the irregular heart rate and automatically record the data.

Number of Electrodes

The number and position of electrodes varies by model, but most Holter monitors employ between three and eight, whereas the Event Monitors typically use two. Both the Holter and Event monitors record electrical signals from the heart via a series of electrodes attached to the chest. The Loop (event) monitor is not attached to the patient but is instead pressed to the chest by the patient when experiencing an A-Fib episode.

Implantable ambulatory event monitors

Medtronic Reveal® DX insertable cardiac monitor (ICM) continuously monitors

Medtronic Reveal® DX insertable continuous monitor

Implantable event monitors are also available for those instances where individuals experience such infrequent symptoms that extended monitoring is needed.

These devices are inserted just under the skin in the chest area during an outpatient surgical procedure. The device may remain implanted for over one year.

Implantable loop recorders have the ability to record events either automatically (auto activated) or by manual activation (self-activated).

Real Time Remote Cardiac Recording

CardioNet MCOTos Event wireless event monitor

CardioNet MCOTos wireless event monitor

An example of the newer monitoring technologies is the Ambulatory Cardiac Telemetry (ACT), a wireless cardiac telemetry system.  This event monitor is designed for remote arrhythmia monitoring in any location.

A small transmitter worn on the patient sends the ECG data to a portable handheld device where it is analyzed.  If an arrhythmia is identified, the data is automatically transmitted to a Monitoring Center for immediate review. Integrated into a state-of-the-art mobile phone, the ACT provides next generation cardiac arrhythmia monitoring. What’s interesting is the transmitter is a dongle type device worn around the neck with leads placed on the chest. You carry or have available what, in essence, is a mobile phone (it’s actually more than a phone). It is small and not cumbersome.

No patient input is required. Data collected from the monitors is transmitted to the monitoring center via a cellular network, the internet, or over the phone (based on model). Data from the monitors is not intended to be used directly by the patient but rather by the monitoring center and your cardiologist.

Next-Generation: the ‘Smart Band-Aid’ Patch

Steve wearing Carnation Ambulatory Monitor (for 1 week in Sept 2018 ) at

 BardyDx Carnation Ambulatory Monitor

The ‘Smart Band-Aid’ provides the next-generation ambulatory cardiac monitoring service with beat-to-beat, real-time analysis, automatic arrhythmia detection and wireless ECG transmission. The Zio XT Patch by iRhythm Technologies and the BardyDx Carnation Ambulatory Monitor by Davis Medical are two next generation ambulatory monitors.

The sensors can be modified to monitor a number of different tasks as they can also provide a comprehensive suite of post-symptom, looping, and auto trigger event monitors as part of its turn-key cardiac event monitoring service.

For Steve’s first-hand account of the Medtronic Reveal LINQ loop recorder and the 7-day BardyDx Carnation Ambulatory Monitor, see our post: Has My A-Fib Returned? 21 Day Results from My LINQ Loop Recorder.

VIDEO: The Zio® Patch Ambulatory Cardiac Monitor


The single use Zio® Patch cardiac monitor (iRhythmi Technologies) looks similar to a 2-by-5-inch adhesive bandage and sticks to a patient’s chest. The single-use ambulatory, continuously cardiac monitor records for up to 14 days with no need to remove it during exercise, sleeping or bathing.  (2:04 min.) Go to video->

References for this article
Diagnosing Heart Disease: Ambulatory ECG, Cardionetics, Cardiac Intelligence. Last accessed, Sept 14, 2012.

Anderson, J, et al. New Methodlogies in Arrhythmia Monitoring, Touch Briefings 2008, European Cardiology, pp63-66.

Anderson, J., & Donnelly, N. New Methodologies in Arrhythmia Monitoring. Last accessed Nov 4, 2014. URL:

First posted: March 2013

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If you find any errors on this page, email us. Y Last updated: Saturday, February 16, 2019

Understanding the EKG Signal

By Steve S. Ryan, PhD

Video: Cardiac Conduction System and its Relationship with ECG. Go to video.

An electrocardiogram, ECG (EKG), is a test used to measure the rate and regularity of heartbeats, as well as the size and position of the chambers, the presence of any damage to the heart, and the effects of drugs or devices used to regulate the heart.

The ECG signal strip is a graphic tracing of the electrical activity of the heart. It measures the length of time it takes for the initial impulse to fire at the Sinus Node and then ends in the contracting of the Ventricles.

Schematic diagram of normal sinus rhythm for a human heart as seen on ECG; Public Domain image;

Schematic diagram of normal sinus rhythm for a human heart as seen on ECG

The first upward pulse of the EKG signal, the P wave, is formed when the atria (the two upper chambers of the heart) contract to pump blood into the ventricles. In A-Fib you will see many “fibrillation” beats instead of one P wave.

The next large upward spike segment, the QRS Complex, is formed when the ventricles (the two lower chambers of the heart) are contracting to pump out blood. The normal duration (interval) of the QRS complex is between 0.08 and 0.10 seconds.

The next section, the ST segment, measures the end of the contraction of the ventricles to the beginning of the rest period before the ventricles begin to contract for the next beat.

The next slight rising section, the T wave, measures the resting period of the ventricles.

ECG (EKG) Strip: Atrial Fibrillation

In the case of Atrial Fibrillation, the consistent P waves are replaced by fibrillatory waves, which vary in amplitude, shape, and timing (compare the two illustrations below).

ECG tracing of normal heart rhythm and heart in A-Fib; Copyright 2012 A-Fib, Inc.

© 2012 A-Fib, Inc.

ECG recorder: special graph Paper

The output of an ECG recorder is a graph (or sometimes several graphs, representing each of the leads) with time represented on the x-axis and voltage represented on the y-axis. A dedicated ECG machine would usually print onto graph paper which has a background pattern of 1mm squares (often in red or green), with bold divisions every 5 mm in both vertical and horizontal directions.

Diagram of electrocardiogram paper; Public Domain image

Diagram of electrocardiogram paper.

Interpreting a ECG strip involves counting the squares of the tracing. For example, by counting the squares of a heart in Normal Sinus Rhythm, you can calculate the heart rate.

Video: Cardiac Conduction System and its Relationship with ECG‬

Click for Video: Cardiac Conduction System

Video: Cardiac Conduction System and its Relationship with ECG‬

Animation with narration about the heart’s conduction system. Schematic diagram and explanation of normal sinus rhythm for a human heart as seen on ECG (3:34 min.)
References & Photo Credits for this article
• Schematic diagram of normal sinus rhythm for a human heart as seen on ECG (with English labels). Wikimedia Common, Public Domain. Last accessed April 13, 2014,

• Diagram of electrocardiogram paper. Public Doman. Last accessed April 13, 2014, URL:

• Schematic diagram of normal sinus rhythm for a human heart as seen on ECG (with English labels). Wikimedia Common, Public Domain. Last accessed April 13, 2014, URL:

• Diagram of electrocardiogram paper. Public Doman. Last accessed April 13, 2014, URL:

Updated August 2014

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If you find any errors on this page, email us. Y Last updated: Saturday, May 11, 2019


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