Stanford Medicine study confirmed Apple watch can help detect atrial fibrillation

The Stanford University School of Medicine on Wednesday (13/11/2019) released the latest results of Apple Heart Study, which was launched in 2017. It’s the third time the team has shared its research data.

The study, conducted by Stanford University and Apple, aims to determine whether the Apple Watch can detect atrial fibrillation, which can indicate serious heart problems. The researchers wanted to determine how the Apple Watch worked and whether it was safe to use.

RESULTS: We recruited 419,297 participants over 8 months. Over a median of 117 days of monitoring, 2161 participants (0.52%) received notifications of irregular pulse. Among the 450 participants who returned ECG patches containing data that could be analyzed — which had been applied, on average, 13 days after notification — atrial fibrillation was present in 34% (97.5% confidence interval [CI], 29 to 39) overall and in 35% (97.5% CI, 27 to 43) of participants 65 years of age or older. Among participants who were notified of an irregular pulse, the positive predictive value was 0.84 (95% CI, 0.76 to 0.92) for observing atrial fibrillation on the ECG simultaneously with a subsequent irregular pulse notification and 0.71 (97.5% CI, 0.69 to 0.74) for observing atrial fibrillation on the ECG simultaneously with a subsequent irregular tachogram. Of 1376 notified participants who returned a 90-day survey, 57% contacted health care providers outside the study. There were no reports of serious app-related adverse events.

CONCLUSIONS: The probability of receiving an irregular pulse notification was low. Among participants who received notification of an irregular pulse, 34% had atrial fibrillation on subsequent ECG patch readings and 84% of notifications were concordant with atrial fibrillation. This siteless (no on-site visits were required for the participants), pragmatic study design provides a foundation for large-scale pragmatic studies in which outcomes or adherence can be reliably assessed with user-owned devices. (Funded by Apple; Apple Heart Study number, NCT03335800. opens in new tab.)


The study confirmed that the Apple Watch could detect atrial fibrillation. Dr. Mintu Turakhia, a professor at Stanford University and co-author of the study, said the trial was generally successful, especially in determining how many people would get heart-related notifications from the Apple Watch and what they meant for patients, doctors, insurance companies.

Another researcher who wasn’t involved in the study, said that the technology was promising, but that more than half of the participants were under the age of 40, and that the risk of atrial fibrillation in the group was low, leading to concerns that it might scare healthy people.

A New York cardiologist said that Apple Watch may find early signs of atrial fibrillation in young people, where medical staff do not know how to treat it. “We just don’t know much about the atrial fibrillation of the 35-year-old,” he says. “

The overall benefits of the study, which demonstrates the potential for large-scale studies that use a variety of techniques to remotely monitor patients without the need for on-site medical treatment.