Continuing research by Stanford and Apple from the 2017 Apple Heart Study, which managed to enroll more than 400,000 participants and became one of the largest studies of its kind ever performed, has shown that the Apple Watch is capable of detecting other types of arrhythmic heart beat irregularities in addition to atrial fibrillation (AFib). Apple Watch currently offers potential atrial fibrillation detection and notifications as one of its core health features, introducing it to the device with its Series 4 update, which added an electrocardiogram (ECG) sensor.
The results of the Apple Heart Study proved the science behind that feature, which Apple itself has always positioned as a way to be more aware of your health and potential conditions that may affect your heart health, rather than any kind of very accurate predictor or actual medical device. But over the years there have been many verified stories of Apple Watch users who credit the AFib notification feature as the reason they were able to catch an otherwise asymptomatic issue early thanks to follow-up care from a doctor.
This additional research from the Heart Study dives deeper into the data gathered to show that for 40% of participants who received a notification about a potential irregular heartbeat from their Apple Watch, but for whom follow-up testing with a medical ECG didn't show AFib, there were other arrhythmias present. These included premature atrial complexes, premature ventricular complexes and non-sustained ventricular tachycardia. These are fairly common, and often identified by those who experience them as heart palpitations, but premature complexes in particular could be an indicator of other underlying problems.
The new study, published in the American Heart Association's Circulation Journal, also found that nearly a third of participants who had no AFib detected using the ECG patch after receiving a notification were in fact diagnosed with atrial fibrillation by the end of the Heart Study, indicating that the Apple Watch may have been detecting cases early which the subsequent ECG patch had missed. That would suggest a higher efficacy for the Apple wearable than shown in prior studies.
There's always a lot of speculation about potential new sensors and technical capabilities being introduced to new generations of Apple Watch, but we've already seen that research from large-scale studies like the Apple Heart Study, and the Apple Heart and Movement Study can provide a pathway to new capabilities using existing hardware and sensors, too. Apple Watch showing promising results in terms of detecting other heart arrhythmias might just fit into the category of explorations that find their way to more Health features in future.