Q&A: Can my new Apple watch save me from a stroke?

Q:  Can the new Apple Watch Series 4 save me from a stroke?

A:  The new Apple Watch Series 4 was recently unveiled and it offers something it hadn't in previous generations — an electrocardiogram, or EKG, feature.

The Apple Watch Series 4 has two EKG apps. They monitor for atrial fibrillation, an irregular heart rhythm that can lead to stroke, and can also detect and record unusually slow or fast heart rates. The apps are approved by the U.S. Food and Drug Administration.

While health apps in general can help patients take charge of their health, I still urge users to embrace technology with caution.

The EKG feature is a brand new technology and it will take time to fully understand the accuracy of the apps. According to a study by Apple, the app can detect atrial fibrillation 99 percent of the time. But, perhaps more importantly, there is no data yet that shows it helps people get medical treatment sooner.

Furthermore, atrial fibrillation is more common in those aged 65 and older. It is rare in the younger population. Even with a very accurate test of the condition, some tests will come back as false positives.  This could be particularly true if the watch picks up an irregular heartbeat in a younger person, where it's just that — an irregular heartbeat, not atrial fibrillation.

The Apple Watch Series 4 EKG apps will not work like an office-based EKG, which uses about 12 electrodes on the chest to detect and analyze the heart's electrical signals. Users, especially those with heart conditions, should not be overconfident thinking they're safe from a heart attack or lethal rhythm because they're wearing the watch.

Technology featuring heart monitors is not new. Many fitness trackers and smart watches offer heart monitors, however, their accuracy has been known to vary.

From a clinical perspective, I see the Apple Watch Series 4, which starts at $399, as a heart rhythm recording device. The benefit is that it has the potential to gather information that physicians might be able to use. For instance, it could be useful for heart patients if symptoms are not present during an office visit.

But patients should not self-diagnose with the watch. EKG apps do not replace a visit with your physician, even if you think that your heart rhythm has been fine according to the watch.  If you buy the watch and are using it, let your physician know and share that data with him or her. Your physician's input should guide you on the app, not the other way around.

Vivek Sailam, M.D., is a clinical cardiologist with Lourdes Cardiology.