Apple Watch ECG troubleshooting: common problems and how to fix them
Most Apple Watch ECG problems fall into a handful of buckets: the app won't record, the recording comes out unusable, the trace looks wrong, or your recordings don't show up afterwards. This page is a map, find your symptom below and jump to the full fix. Almost none of these are about your heart; they're about getting a clean 30-second reading and getting it onto your phone.
Start with the obvious one: if your watch won't record an ECG at all, check the model first. Apple Watch SE (any generation) has no ECG sensor, so it cannot record an ECG. Everything below assumes a Series 4 or later.
Setting up and taking a recording
If you're just getting started, or the ECG app is missing from your watch:
- How to set up ECG on Apple Watch — check compatibility, enable ECG in the Health app, and fix a missing ECG app.
- How to record an ECG on Apple Watch — start a reading in two taps, and what to do if the app won't open or your region doesn't support it.
- How to get a clean recording every time — the simple habits that make every reading usable.
The recording won't complete, or the quality is poor
The reading starts but never finishes, or the trace comes out fuzzy, spiky or drifting. This is almost always about the electrical contact, not your heart:
- Fix a "poor recording" — usually damp skin or a damp watch back; how to get completely dry contacts.
- The countdown keeps restarting — why the timer resets to 30 and never finishes, and how to hold a steady contact.
- Baseline wander (the trace drifts up and down) — what causes it and how to steady it.
- EMG artifact (fuzzy, spiky noise) — muscle tension in the arm, and how to relax it out.
The trace looks wrong
The recording finished, but something about it looks off:
- The ECG is upside down — usually the wrist or orientation setting not matching how you wear the watch.
- The P wave is missing or faint — why the smallest wave is so often lost on a single-lead watch recording, and when it matters.
- What "inconclusive" means — why the watch couldn't classify the rhythm, and how to get a clear result.
Your recordings aren't showing up
You took a reading, but it isn't where you expect it:
- New ECGs aren't appearing on your iPhone — almost always iCloud Health sync; a ten-second check tells you for sure.
- Recordings are slow to reach your iPad — why the iPad lags behind the iPhone, and how to speed it up.
Getting more from a good recording
Once you can take a clean reading, there's more you can do with it:
- Record Lead II and other leads — repositioning the watch for a clearer view of atrial activity.
- What ECG+ marks on your recording — the premature beats, patterns and intervals the built-in app doesn't label.
- What to ask your doctor — how to turn a recording into a useful conversation.
- ECG+ frequently asked questions — the full FAQ, including subscription and accuracy questions.
Still stuck after all this? A recording that consistently won't complete, on either wrist and after a restart, can point to a hardware issue with the watch, which is worth having Apple Support check. And if the problem is your recordings not appearing rather than not recording, it's an Apple Health/iCloud sync issue, not an app you can reinstall your way out of.
Frequently asked questions
Why won't my Apple Watch record an ECG at all?
First check your watch model. Apple Watch SE (any generation) has no ECG sensor, so it cannot record an ECG. On a Series 4 or later, make sure the ECG app is installed and set up, your region supports it, and your wrist and Digital Crown are clean and dry. The setup and how-to-record guides walk through each step.
Why does my Apple Watch ECG say "poor recording" or keep restarting?
Both come down to the electrical contact during the reading. A "poor recording" is usually damp skin or a damp watch back; a restarting countdown means the contact broke or was too noisy for a moment. Dry your wrist, fingertip and the watch, rest your arm, hold a light steady finger on the Digital Crown, and stay still for the full 30 seconds.
Why aren't my new Apple Watch ECGs showing on my iPhone?
New recordings reach your iPhone through iCloud Health sync. If recent ECGs are missing from the Apple Health app too, iCloud Health sync is almost always the cause. On iPad, recordings simply arrive later than on iPhone.