ECG guides

Understand your Apple Watch ECG

Learn what a 30-second single-lead recording can show, what its limits are, and how to review informational estimates without turning them into a diagnosis.

Start with a question

Single-lead ECGWhat your Apple Watch ECG can show

Understand the 30-second waveform and how it differs from a clinical 12-lead ECG.

 QT and QTcQT and QTc, explained without the guesswork

See why correction formulas differ and why one estimate is not a clinical conclusion.

 HRVHRV from a 30-second ECG

Learn what rMSSD and SDNN summarize and where an ultra-short recording falls short.

 Premature beatsPossible premature-beat patterns

Understand possible PAC and PVC pattern flags and why clinician review matters.

ECG Tracker+

Explore your Apple Watch ECG in more detail

View the full waveform, informational measurements, trends, and possible premature-beat pattern flags on your iPhone. Processing stays on-device.

Download on theApp Store