Understand your Apple Watch ECG

P wave, QRS, T wave, heart rate and intervals. A step-⁠by-⁠step guide to your 30-⁠second strip.

Sinus Rhythm, AFib, High or Low Heart Rate, Inconclusive and Poor Recording, explained one by one.

One lead from your wrist vs twelve views in a clinic. What each captures and when each is used.

Health gives you the recording and Apple's classification. An ECG app adds measurements, trends and context.

A practical checklist for comparing ECG apps on measurements, honesty, privacy and price.

A uniform rhythm between 50 and 100 bpm in that recording. What it shows and where its limits are.

Heart rate, extra beats, pacemakers or signal. Why the Watch cannot classify some recordings.

Poor Recording, noise or finger not detected. Seven fixes for a cleaner recording.

Usually a wrist setting that does not match. How to check Watch Orientation and record again.

What each grid box means and how to measure timing yourself with calipers.

One heartbeat up close, with P, QRS and T markers and the intervals between them.

A real single-⁠lead example of a wide QRS, the common causes and what one lead cannot confirm.

A real single-⁠lead example, what can turn the T wave over and how it differs from a flipped recording.

A real Apple Watch recording, how R-⁠R becomes beats per minute and what the usual ranges are.

What each interval measures, typical adult ranges and what a single-⁠lead recording can show.

What the small wave before each beat shows, its typical length and why it can be hard to measure.

From the start of the P wave to the start of the QRS, with typical ranges and what changes it.

How long the main spike of each beat lasts, the typical range and what a wide QRS can mean.

The height of the main spike in millivolts, why it varies and what it does not measure.

How QTc is calculated, typical ranges, why formulas disagree and what a watch recording can show.

rMSSD vs SDNN, why Apple Health's HRV is different and what a 30-⁠second ECG can show.

Locked, still analyzing or not measurable. How to tell them apart and what each one means.

Your recording stays the same. A newer analysis can read it a little differently.

What extra beats look like on the waveform, why they are only possible and what a 30-⁠second strip cannot tell you.

A real single-⁠lead example, the four signs to look for and what one strip cannot tell you.

A real single-⁠lead example, the signs to look for and how a PAC differs from a PVC.

A real single-⁠lead example, how to recognize the pattern and what one strip cannot tell you.

A real single-⁠lead example of the two-⁠normal, one-⁠early rhythm and what one strip cannot tell you.

What the median, latest value and plain-⁠language recap tell you about your recordings over time.

A general adult range and your own history answer different questions. How to read both.

Optical heart rate all day, ECG on demand. How they differ and how to see them together.

Tag it, exclude the tag, keep the recording. Your Trends stay yours.

Search, tag, note and export. A simple routine that makes your recordings easy to discuss.

Apple's PDF from Health, or a detailed report with measurements. Both, step by step.

Check Health first, then filters, import and permissions. Most missing ECGs are one of these four.

Record with Apple's ECG app, then review measurements and Trends on your wrist.

Your iPhone prepares every result. Here is how to follow a new ECG from wrist to phone and back.