Harvard Health Ad Watch: How helpful are pulse monitors and home ECGs? - Harvard Health

Harvard Health
By: Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing
July 06, 2021

Want a device that lets you regularly check on how your heart is doing? 

  • Products like KardiaMobile devices let you perform an electrocardiogram (ECG) anytime you like, 
  • while certain Apple watches can also perform ECGs as well as alert you if your heart rate is too fast, too slow, or irregular.

But do any of us need this? 

Perhaps — or perhaps not. 
Before you decide, let’s consider a few ads and understand the pros and cons of these devices.

Marketing heartbeat and ECG monitoring

A healthy man at his dining table looks up at the camera as he presses a button on his watch. “This app lets me take an ECG without needing an appointment, or a fancy machine, or even needing to move a muscle,” he says while his surroundings change. He’s playing chess, watching a tennis match, seeing his dentist, lounging on the beach, watching a movie, enjoying a tropical butterfly exhibit, and, finally, fishing on a river, all the while holding down that button. “‘Cause if I want to take an electrocardiogram, I’m going to take an electrocardiogram,” he adds. The watch face completes a 30-second countdown and delivers the good news: his heart rhythm is normal. The ad ends with these words on the screen: The future of health is on your wrist.

Sadly, we don’t have a “check engine” light for the heart — which is where a home ECG device comes in, according to one marketing push.

In a third ad, a voiceover says: “One day, your watch will be able to take an ECG.” A young jogger glances at his watch, then looks up to say “It already does that” before resuming his run.

Yet a fourth ad offers a menu of online videos, including firsthand accounts of people “saved” by their monitoring devices:

  • A teenager wears a watch with a heart rate monitor to help with sports training. An alert leads to the discovery of a dangerously fast heart rate.
  • A middle-aged man alerted to a fast heart rate turns out to have blood clots in the lungs, a potentially life-threatening condition.
  • A young man who has quadriplegia is awakened by an alert that his heart is beating fast. Soon after, he’s found to have a serious, bodywide infection called sepsis.

What’s right about these ads?

These ads get a number of things right:

  • Heart rate is one of several vital signs that can signal medical conditions warranting attention, including serious problems like blood clots in the lungs (pulmonary emboli) or sepsis. Depending on the condition, heart rate might be much slower or faster than normal. Unstable and dangerous heart rhythms can be life-threatening, and require quick diagnosis and treatment.
  • Home ECGs can detect atrial fibrillation and long QT syndrome, which can cause serious, even life-threatening complications, and require prompt detection and treatment. While access to an ECG — and being able to send one to a physician to interpret — is unlikely to be helpful for healthy people, it may help some people with heart problems. Studies of home medical monitors (including this one and this one) demonstrate the potential for home monitoring devices to accurately detect these conditions.

What’s missing?

These ads don’t provide a complete picture. For example:

  • When screening a general population, the overall rate of detecting something significant is quite low. One of the largest studies to look at using a smartwatch to detect atrial fibrillation found only 43 of 293,944 people (0.015%) had new instances of this condition. Many other studies included only people at higher-than-average risk for irregularities, such as those with congenital heart disease or prior atrial fibrillation.
  • The testimonial videos are heart-wrenching and dramatic, but most describe conditions for which these devices have not been studied and weren’t designed to detect, such as blood clots or sepsis.
  • Home ECG tests provide more limited information than standard tests in doctors’ offices or hospitals. They cannot determine if you’re having a heart attack, or had one in the past. (There is an easily missed disclaimer in the ads about this.)
  • The US Preventive Services Task Force and the American College of Cardiology do not recommend routine ECGs (at home or done by a physician), or monitoring heart rate for atrial fibrillation in the general population.

What are the downsides to heart rate monitoring and home ECGs?

  • Cost. These devices are not inexpensive, and are unlikely to be covered by health insurance.
  • False alarms. Even with a healthy heart, most people have periods of faster and slower heart rates that could trigger alerts, causing unnecessary anxiety, additional testing, and treatment.
  • False reassurance. A normal ECG tracing does not mean the heart is healthy. An ECG, especially the type performed at home, is simply not a great screening test for overall heart health.
  • Avalanche of data. Who will interpret the data collected, particularly when an alarm goes off — or whenever you have a home ECG? One product offers the option of having a cardiologist read your ECGs four times a year (for $9.99/month). But if your data goes to your primary care doctor, they may recommend less rather than more monitoring at some point.

Is buying one of these devices a good idea?

Heart rate monitoring or home ECG testing might be helpful for a person who has had intermittent symptoms that could be due to atrial fibrillation or another abnormal heart rhythm, is taking medicine that can affect heart rhythm, or to monitor someone who has previously had atrial fibrillation. But for the average person with no symptoms and no risk factors for these problems, any benefit is doubtful.

If you feel concerned that your heart is going too fast or too slow, you can always check it yourself: just count your pulse for 15 seconds and multiply by four. And talking to your medical team about your heart health may reassure you, or point to the need for screening.

The bottom line 

Health monitoring is big business, and the makers of devices you see advertised would have you believe you’d better get one as soon as you can. 

But the question we should each be asking is this: what monitoring is useful to embrace and what is unnecessary, annoying, or even harmful? 

Notably, many people who use technology to monitor their health stop using it within a year. So, while the future of medicine might truly be on your wrist, it might instead wind up sitting unused in your dresser drawer.

Devices that monitor heart rate and rhythm or check home ECGs are the latest examples of amazing technology that, in my view, has gotten ahead of the science: 

  • they may be useful for some people in certain circumstances
  • but we don’t yet have compelling evidence that they are helpful for everyone. 

My advice? Skip the gadgets and instead invest in something more likely to actually improve your health, like a pair of good walking shoes.

Originally published at https://www.health.harvard.edu on July 6, 2021.

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