The Apple Watch may help catch A-Fib

Posted Thursday, April 4, 2019 by Carl-Erich Kruse

Many of us wear fitness trackers. Since they hit the market just over a decade ago, the functions of the devices have continued to expand. Fitbit, for example, bills itself no longer simply in the business of wearable technology; instead it identifies as a “digital healthcare company.” While many who wear fitness trackers may obsess of the number of steps they have amassed in day or their quality of sleep, the evolution of these products may be offering you and me more significant health benefits.

This blog has previously discussed the possibilities of heart monitoring with the Apple Watch. Now, preliminary results from a study – sponsored in part by Apple – have shown that a fitness tracker, in this case in the form of the Apple Watch, may be effective in identifying heart conditions such as atrial fibrillation, or A-fib.

A-fib is a condition wherein the atria of the heart, the upper chambers, beat irregularly. The condition may lead to blood clots, strokes, and heart failure. Millions of Americans have A-fib. Interestingly, the most recent model of the Apple Watch, which itself features an ECG, was not part of this study.

The so-called Apple Health Study found that the Apple Watch had a 71% positive predictive value, meaning 71% of those study participants whom the Apple Watch found to have A-fib actually had it. Perhaps most importantly, the study found that, of the study participants who were notified of an irregular heart rhythm, 84% were verified by a doctor as having had an episode of atrial fibrillation. This second statistic is important if only to calm worries of overreporting and overburdening cardiologists’ offices.

Fitness trackers like the Apple Watch may be able to help consumers identify abnormalities before they are picked up on ECG at a doctors’ office, thereby improving outcomes for patients with certain conditions. We expect to see improved accuracy and functionality as these technologies continue to improve. However, it is unclear whether and to what extent the standard of care will allow for cardiologists and other doctors to rely on this data in treating their patients in the future.