22/04/2026
The Apple Watch ECG app is a built-in feature that allows users to record a single-lead electrocardiogram (ECG) directly from their wrist.
How it works:
The watch uses electrodes on the back crystal and the Digital Crown. When you place your finger on the crown, it completes a circuit across your body, allowing the device to record the heartโs electrical activityโsimilar to Lead I in a standard ECG.
What it detects:
โข Normal sinus rhythm
โข Atrial Fibrillation (AFib)
โข High or low heart rate alerts
โข Inconclusive readings (if signal is unclear)
Recording process:
โข Takes about 30 seconds
โข Results are stored in the Apple Health app
โข Can be exported as a PDF and shared with healthcare providers
Limitations:
โข It is a single-lead ECG (not a full 12-lead ECG)
โข Cannot detect all arrhythmias or conditions like heart attacks
โข Should not replace professional medical evaluation
Summary:
The Apple Watch ECG is a convenient screening tool for basic heart rhythm monitoring, especially useful for early detection of AFib, but it is not a substitute for clinical-grade diagnostics.