A 76-year-old woman presents with a persistently rapid heart rate that she attributes to her pacemaker. What does the ECG show?

Irregular rhythm notifications are available only with watchOS 5.1.2 or later in certain countries. With Apple Watch Series 4, Apple added a electrocardiogram monitoring (also known as ECG and EKG).

Abstract: Arrhythmia, a heart rhythm disorder, remains a serious global health problem ... Although deep learning holds promise for automatic arrhythmia detection using ECG signals, several challenges ...

An ECG records the electrical activity ... It is a non-invasive test that helps identify heart rhythm irregularities, signs of previous heart attacks and other heart conditions early on.