Detecting Atrial Fibrillation with the Apple Watch

With the recent unveiling of the Apple Watch 3, Apple also announced that the company is partnering with researchers and clinicians from Stanford and American Well, a telemedicine company, to launch a study using the Apple Watch’s ability to monitor heart rate in order to detect atrial fibrillation in users.

Atrial fibrillation occurs when the normal electrical conduction of your heart is disrupted. Normally your heart contracts in a well-organized manner. Your veins deliver blood into the first chambers of your heart, the atria, then the atria contract to push blood into the next chambers of your heart, the ventricles, and then the ventricles contract to pump blood out of your heart and into your body and lungs. Abnormal electrical conduction prevents the heart from contracting normally. Instead of contracting, the atria merely quiver, or “fibrillate.” Blood is still able to circulate through your body as long as your ventricles are pumping. However, the blood sitting in the atria is more likely to form a clot, which can later cause a stroke. Many people who have atrial fibrillation therefore are put on blood thinners in order to prevent clots from forming and reduce the risk of stroke.

Atrial fibrillation is the most common cardiac arrhythmia. Strokes related to atrial fibrillation remain a major problem in America, despite the amazing treatments that are available to prevent blood clots. Old studies estimate that 10-20% of the population will develop atrial fibrillation by the age of 80, but the condition is probably even more common than we previously thought!

These older studies were usually done by taking an EKG in the doctor’s office. But atrial fibrillation is not always permanent. Your atria may usually contract normally, but occasionally start quivering. This is called “paroxysmal atrial fibrillation.”

It seems very likely that the Apple Watch study will detect atrial fibrillation at higher rates than what we have previously seen, because it is a device that people wear all the time, instead of only at the doctor’s office or for a few weeks like a Holter monitor.

It is very important to note that we do not know for certain what the risk of stroke is among people who have paroxysmal atrial fibrillation compared to people with permanent atrial fibrillation. With that said, most cardiologists treat the two conditions the same way. We should be cautiously optimistic about our ability to help prevent strokes in many people who have atrial fibrillation without knowing it.

This announcement by Apple is an exciting development in the world of atrial fibrillation and is a remarkable step toward integrating technology with healthcare.

https://www.cnbc.com/2017/09/11/apple-watch-caridac-arrhythmia-tests-stanford-american-well.html

Author

Ibrahim Helmy, MD