Because the atrial rate is so fast, and the action potentials produced are of such low amplitude, P waves will not be seen on the ECG in patients with atrial fibrillation. At times, the P wave ...

Kosman says they want to use the PPG to "passively" catch abnormal heart rhythm overnight and prompt users to take an ECG, but that it's not ready yet. For context, Ultrahuman announced an AFib ...