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What is an ECG?

An ECG is the graphical representation of the heart’s electrical activity, recorded via electrodes. It can detect many cardiovascular pathologies. Learn more.

What is this feature?

The ScanWatch ECG records a 1-lead medical electrocardiogram. Then the exclusive algorithm developed by Withings analyzes the record and detects the possible presence of a rhythm irregularity, while also checking to see if the heart rate is too low or too high.

ScanWatch includes three electrodes to ensure measurement accuracy. Two electrodes are discreetly integrated inside the main body of the watch, and the third electrode is in the stainless steel upper ring (the bezel) of the watch. Users simply need to launch the ECG mode and touch both sides of the bezel with their opposite hand to start recording an ECG anytime and anywhere.


We led several clinical studies to compare ScanWatch measurements with the gold standard and assess its medical accuracy. ScanWatch has received CE medical certification in Europe and is expected to receive FDA clearance in the United States using the results of these clinical studies.

How to record an ECG?


  • You can see your ECG signal in real-time in the Health Mate app.
  • ECG recordings are now available on the Health Mate Online Dashboard. 
  • If you don't have your phone with you, you can still record an ECG on the go via a simple gesture on the watch. Your results will appear on the watch's display and in the Home screen of the Health Mate app the next time you open it.

Understanding your results

After each measurement, ScanWatch will give you the following metrics: heart rate, a 1-lead ECG record, and a rhythm assessment distributed between 3 classes: normal sinus rhythm, atrial fibrillation, or inconclusive.

 Normal Sinus Rhythm 

 A sinus rhythm means your heart is beating in a uniform pattern between 50 and 100 bpm.


 Atrial Fibrillation 

 Atrial fibrillation occurs when the two upper chambers of the heart move chaotically instead of pumping regularly. The P wave on the ECG disappears and is replaced by a jumpy baseline. The QRS complex occurs at "irregularly irregular" intervals. 

If you get this result and you have never been diagnosed, make an appointment with your doctor and share the recording of your ECG. This will allow your doctor to make a diagnosis and offer you an appropriate treatment.



An inconclusive result means the recording can’t be classified. This can happen for many reasons: 

  • Heart rate is too low: The heart rate obtained cannot be classified as a recording. To obtain full analysis, the heart rate must be above 50 bpm during the recording.
  • Heart rate is too high: The recording does not appear to show any signs of atrial fibrillation, but a complete diagnosis is not possible for a heart rate above 100 bpm. To obtain a full analysis, the heart rate must be below 100 bpm during the recording.
  • Signal is too noisy: There is too much interference for the recording to be classified. Place your arm on a table or on your thigh, relax, don’t talk, and don’t move during the recording. Refer to the best practices section to know which gestures to use and which to avoid.
  • Signs of other arrhythmias: This sensor is capable of detecting atrial fibrillation, but is not able to diagnose other types of arrhythmias. This recording cannot be classified as a normal rhythm or atrial fibrillation.

Important: If you think you may be having a heart attack (myocardial infarction) or are facing a medical emergency, call emergency services.

What is AFib?

Atrial fibrillation, or AFib, is the most common cardiac arrhythmia, an anomaly of the heart’s electrical activity. It is caused by a disorganized firing of electrical impulses in the right atrium near the sinoatrial node, the natural pacemaker of the heart, where it is located. Learn more.

Atrial fibrillation (AFib) is thought to be responsible for approximately 30% of strokes. 90% of these events could be prevented if this condition had been diagnosed earlier. Atrial fibrillation is often underdiagnosed because AF is an episodic disease and attacks do not necessarily occur during medical visits.

When the user experiences symptoms such as palpitations, they can launch the ECG mode, place a hand on the watch, and then ScanWatch will record an electrocardiogram by detecting electrical signals from the heart within 30 seconds. Follow the best practices guide for medical-grade results. 

How can I share ECG results with my doctor? 

After recording your ECG, you can choose to send a PDF of your ECG results to your doctor. Click here to learn more.


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