Читать книгу Apple Watch For Dummies - Marc Saltzman - Страница 52

Beginning with Apple Watch Series 4 (except Apple Watch SE), all Apple Watch models include an electrical heart-rate sensor that can take an electrocardiogram (ECG) by using an ECG app; the built-in sensor and the electrodes are included in the Digital Crown button. You take an ECG reading by placing a finger on the Digital Crown while wearing Apple Watch; the reading is completed within 30 seconds. The ECG app tracks whether your heart is beating in a regular pattern or whether you have signs of atrial fibrillation — a clear indicator of serious health problems.