Apple has released watchOS 5.1.2 with the much-awaited ECG app for Apple Watch Series 4, and Irregular Rhythm Notification for Apple Watch Series 1 and above. This fulfills Apple’s promise of making Apple Watch Series 4 the first mainstream consumer product with electrocardiogram reading capability, which can be used by a doctor for diagnosis.
ECG and Irregular Heart Rhythm Notification in watchOS 5.1.2
The ECG app and irregular heart rhythm notification will be used to identify early signed of atrial fibrillation (AFib), which is one of the most common conditions that lead to a stoke. Early detection of AFib can lead to proper treatment which can potentially save lives.
Apple Watch Series 4 has electrodes and sensors which are used for the ECG. Users have to put their finger on the Digital Crown for 30 seconds, which is enough for the ECG app to generate a reading. The report can be exported as a PDF from iPhone Health app, and can be shared with doctors for diagnosis and treatment. The report data is kept privately and securely on device.
With irregular heart rhythm notification on Apple Watch Series 1 and later, watchOS 5.1.2 will keep track of heart rate readings. If irregular heart rhythm is detected 5 times during a duration 65 minutes, the watch will notify the user that it might be a sign of AFib. This will help in a user consulting a doctor on time.
Apple has put a lot of time and resources to ensure that the ECG recordings are as accurate as possible. Their clinical trials confirmed the accuracy:
The ECG app’s ability to accurately classify an ECG recording into AFib and sinus rhythm was validated in a clinical trial of around 600 participants. Rhythm classification from a gold standard 12-lead ECG by a cardiologist was compared to the rhythm classification of a simultaneously collected ECG from the ECG app. The study found the ECG app on Apple Watch demonstrated 98.3 percent sensitivity in classifying AFib and 99.6 percent specificity in classifying sinus rhythm in classifiable recordings. In the study, 87.8 percent of recordings could be classified by the ECG app.
The irregular rhythm notification feature was recently studied in the Apple Heart Study. With over 400,000 participants, the Apple Heart Study was the largest screening study on atrial fibrillation ever conducted, also making it one of the largest cardiovascular trials to date. A subset of the data from the Apple Heart Study was submitted to the FDA to support clearance of the irregular rhythm notification feature. In that sub-study, of the participants that received an irregular rhythm notification on their Apple Watch while simultaneously wearing an ECG patch, 80 percent showed AFib on the ECG patch and 98 percent showed AFib or other clinically relevant arrhythmias.