The study was launched in November of 2017, and was a first-of-its-kind research study using Apple Watch’s heart rate sensor to collect data on irregular heart rhythms and notify users who may be experiencing atrial fibrillation (AFib). The condition often remains hidden because many people don’t experience symptoms.
Key findings from the study include:
- Overall, only 0.5 percent of participants received irregular pulse notifications, an important finding given concerns about potential over-notification.
- Comparisons between irregular pulse-detection on Apple Watch and simultaneous electrocardiography patch recordings showed the pulse detection algorithm (indicating a positive tachogram reading) has a 71 percent positive predictive value. Eighty-four percent of the time, participants who received irregular pulse notifications were found to be in atrial fibrillation at the time of the notification.
- One-third (34 percent) of the participants who received irregular pulse notifications and followed up by using an ECG patch over a week later were found to have atrial fibrillation. Since atrial fibrillation is an intermittent condition, it’s not surprising for it to go undetected in subsequent ECG patch monitoring.
- Fifty-seven percent of those who received irregular pulse notifications sought medical attention.
As part of the study, if an irregular heart rhythm was identified, participants received a notification on their Apple Watch and iPhone, a telehealth consultation with a doctor, and an electrocardiogram (ECG) patch for additional monitoring.
In short, it appears that the Apple Watch is able to detect AFib. This is good news, because it means people can take that information to their doctor and start a discussion about what to do next. It does not mean people should rely entirely on the results the Apple Watch gives them and avoid seeing a doctor.