Some Apple Watches have an electrocardiogram (ECG or EKG) built in. If your doctor wants you to use it—or you want to share the results of it with them—here’s what to do.
Read This First
But first, a few quick notes:
The author of this piece is not a doctor. This is a technology article on a feature of the Apple Watch. If you are concerned about your health, contact your doctor. The Apple Watch does not detect heart attacks. If you are experiencing any of the symptoms of a heart attack, seek medical attention immediately. The ECG app is not available in all countries due to differences in legislation around health care devices.
What Apple Watches Have an ECG?
The Apple Watch Series 4, Series 5, and Series 6 have a built-in ECG. The Apple Watch SE and Apple Watch Series 3, both of which are still available for sale as of early 2021, do not.
How to Take an ECG with Your Apple Watch
Before using the ECG app, you need to enable it in the Health app on your iPhone. If you haven’t already done so, open the “Health” app and tap “Set Up ECG app.”
If you don’t see it, go to “Browse” > “Heart” > “Electrocardiograms (ECG),” then tap “Set Up ECG App,” and follow the setup instructions.
On your Apple Watch, open the ECG app. Rest your arms on a table or on your legs, and hold your finger on the Digital Crown. The ECG will automatically start.
Wait 30 seconds for the recording to complete. When the timer ends, you’ll see the results of the ECG. These include:
Sinus rhythm: Your heart is beating normally between 50 and 100 BPM. However, this does not necessarily mean that you are healthy. If you feel unwell, contact your doctor. Atrial fibrillation (or AFib): This is one of the health conditions your Apple Watch can detect. If you get this result, it means that your heart has an irregular rhythm. Contact your doctor. Low heart rate or high heart rate: Your heart rate is lower than 50 bpm or higher than 150 bpm (or 120 bpm with ECG app version 1). Inconclusive: The results can’t be classified for some reason. You can get this result if you have a heart condition that the app is not designed to detect, if you have a pacemaker, or (with ECG app version 1) if your heart rate is between 100 and 120 BPM and you do not have AFib. If you’re concerned about your heart, contact your doctor. Poor recording: The results can’t be classified. Make sure that your Apple Watch fits properly and that your arms are resting on something, and try again.
Tap “Add Symptoms” if you want to add additional details about how you’re feeling. Otherwise, tap “Done.”
Remember, the ECG app does not detect heart attacks. Do not use it in place of professional medical care.
How to Share Your ECG with Your Doctor
To view an ECG and share it with your doctor, open the “Health” app on your iPhone and go to “Browse” > “Heart” > “Electrocardiograms (ECG).”
You’ll see your three most recent ECG recordings. To view older ones, scroll down and tap “All Data.” You can also view them by the different results categories.
Tap the ECG that you want to share, then tap “Export a PDF for Your Doctor.”
Tap the share icon in the top-right corner to bring up the Share Sheet.
Depending on how your doctor wants you to send the ECG, you’ll likely need to select “Mail” to email the file or “Messages” to send it as an iMessage.
