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A Cardiologist’s Take on Smartwatch ECG Monitors and Heart Health

If your watch could detect a serious health problem, how often would you turn to it?

Editor’s Note: This article was updated from an earlier version posted in July 2021.

Since smartwatches have become increasingly popular over the last few years, health experts have been weighing the conundrum of whether the wearable technology is more beneficial or detrimental.

With innovative tools to help track your fitness and health – such as pedometers, blood oxygen sensors/pulse oximeters, electrocardiograms (ECGs), and even electrodermal activity (EDA) sensors to monitor skin temperature and stress –  some people are starting to rely on their wrists for answers the same way they once did with Google, suggests David L. Fischman, MD, FACC, Jefferson Health Cardiologist.

“While these tools yield incredible potential, it’s important that we remember they’re not able to give a diagnosis,” says Dr. Fischman. Some apps are FDA-approved, while others are still undergoing extensive studies and awaiting approval – meaning, in many cases, errors/false readings can occur.

It’s not all bad news though, continues Dr. Fischman. In other cases, specifically with an FDA-approved ECG that can detect atrial fibrillation, there are potential health advantages. So, how do these monitors work, who can benefit from them, and who can more or less leave them alone?

Can a smartwatch ECG detect a heart attack?

No, says Dr. Fischman. “Some testimonials claim this, but there are many other factors involved. Plus, an ECG alone doesn’t diagnose a heart attack; it can indicate a previous or impending one but is often complemented with other tests.”

How does a smartwatch ECG differ from a standard ECG monitor in the doctor’s office?

ECGs record the heart’s electrical signals on a telemetry strip with leads/waveforms; a standard ECG has 12 leads, whereas most smartwatches only have one, explains Dr. Fischman. Single-lead ECGs are used only to monitor basic heart function, and they shouldn’t replace medical-grade devices. Some patients are sent home with monitors that use multiple; these are currently more sensitive and specific than smartwatches, especially when detecting AFIB.

What is AFIB and what does it put us at risk for?

AFIB is an irregular heart rhythm that develops with age. Among other risk factors are heart disease, obesity, and family history, says Dr. Fischman. “AFIB occurs due to a disturbance in the left atrium that sends chaotic signals to the main pumping chamber of the heart, decreasing cardiac output. This can cause symptoms of shortness of breath, fatigue, and feeling a ‘funny’ heartbeat. However, nearly 50 percent of people with AFIB are asymptomatic.”

Undiagnosed/untreated AFIB is dangerous, as it can increase the likelihood for stroke in some people. In terms of treatment, asymptomatic AFIB may only require a blood thinner, says Dr. Fischman, but if there are symptoms that are impacting quality of life, we try to get them back into a normal rhythm by shocking the heart (cardioversion) or using antiarrhythmic drugs.

What should you do if you see an AFIB alert?

If you’ve never been diagnosed with AFIB, you should call your physician and set up an appointment with a cardiologist within the next few weeks, suggests Dr. Fischman. It’s not urgent, but you also don’t want to put it off (in case you’re at risk for stroke). If you’re young and otherwise healthy, the reading might be false or might be from palpitations, perhaps due to stress.

“If you already know you have AFIB, on the other hand, seeing that alert can help you monitor the frequency of your episodes,” added Dr. Fischman. “If episodes are becoming more common, you should address this with your physician, as you may need to alter your treatment.”

What are the greatest benefits?

Some smartwatches can serve as an easy, accessible monitor for those who have AFIB, and they may play a promising role in precision medicine, says Dr. Fischman.

The ‘Pill-in-Pocket’ Approach – this aims to decrease the need for certain medications. Rather than constantly taking a pill, one could take it temporarily after symptoms or episodes appear. People already do this with antiarrhythmic drugs. It’s not a new concept, but new studies are being done to see how smartwatches could work as effective monitoring systems to decrease the need for AFIB medications, particularly blood thinners, explains Dr. Fischman.

When do you need to use an ECG app?

Only if you feel like something’s wrong (i.e., if you’re having palpitations). If you feel fine, stay off it, says Dr. Fischman.

Can watching your watch make it worse?

If we’re not careful, obsessing over numbers/readings can impact mental well-being, says Dr. Fischman. Continuously using an ECG monitor isn’t going to change the readings you receive or what’s really going on in your body; however, watching the heart rate monitor could.

People tend to panic at the sight of a high BPM (beats per minute), but if you feel okay, that number could be due to an inaccuracy with the technology or consumption of things that elevate heart rate, such as alcohol, salt, and nicotine, explains Dr. Fischman. “Being overweight is another risk factor for a more rapid heart rate. Plus, the act of watching that number rise can trigger anxiety, making the number rise even more – like an endless cycle.”

To remember:

“Don’t get overwhelmed or try to self-diagnose. There’s no such thing as ‘Dr. Watch,’” said Dr. Fischman. “Smartwatches are great tool that can provide some insight into your health, but their readings are not the ‘end-all and be-all.’”

If you have a diagnosed cardiac problem, you should always let your physician know when you feel something is wrong. They can also let you know the best way to use your particular smartwatch for your own unique condition.

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