Apple has been granted De Novo classification by the FDA for the Apple Watch Series 4. This certification as a unique device allows Apple Watch customers running watchOS 5.1.2 access to features that enable the detection of irregular heart rhythms. Consumers will be notified when the PPG-enabled algorithm detects an irregular heartbeat. The electrical heart sensor, in conjunction with the companion ECG app, generates an ECG similar to a single-lead (Lead I) ECG to look for the presence of atrial fibrillation (AF) with a greater than 98% sensitivity and 99% specificity when compared to reference ECG devices. The device can distinguish between a normal heartbeat, or sinus rhythm, and atrial fibrillation. Other features of the Apple Watch Series 4 include access to Medical ID and fall detection.