Disclaimer: Due to health regulations and clearances, some ScanWatch 2 features may not be available or may not have clinical validation in your region. Learn more.

What is an ECG?

ECG, or electrocardiogram, is the graphical representation of the electrical activity of the heart. It can detect certain cardiovascular pathologies.

With each heartbeat, an electrical wave travels through your heart. This wave causes your heart to contract and pump blood.

The gold standard ECG records 12 lead (or ways) of the heart. Withings ECG devices sense the electrical activity of the heart at a distance through the left and right arm. This configuration is known as lead D1.

Which conditions can Withings ECG devices detect ?

ECGs can detect a range of conditions, from angina pectoris to severe heart attacks. Withings ECG devices focus on detecting atrial fibrillation. If you believe you are having a heart attack, contact emergency services.

What do practitioners look for in the ECG graph?

A normal heartbeat on the ECG graph will show the time the electric wave takes to move through your heart. There are 3 distinct patterns:

By measuring time intervals on an ECG, practitioners can find out if this electricity travel is too slow, normal, too fast, or even irregular. Such indicators can point to an oversized or overworked heart.

ECG Results you may see

Low Heart Rate	A Low Heart Rate result means your heart is beating less than 50 beats per minute (bpm). This recording cannot be classified by the device. A low heart rate can happen if electrical signals are not properly conducted through the heart. Some medicines can also cause a low heart rate. Talk to your doctor if you have questions about your ECG recording.
High Heart Rate	A High Heart Rate result means your heart is beating above 150 beats per minute (bpm). This recording cannot be classified by the device. Many different things can cause a high heart rate. A heart rate may be high because of exercise, stress, dehydration, infection, AFib, another arrhythmia or another cause. Talk to your doctor if you have questions about your ECG recording.
Normal Sinus Rhythm	A Sinus Rhythm result means your heart rate is between 50 and 99 beats per minute (bpm) and is beating regularly.
High Heart Rate (No signs of AFib)	A High Heart Rate (No signs of AFib) result means the heart rate is beating between 100 and 150 beats per minute (bpm) and does not show any signs of Atrial Fibrillation.  Many different things can cause a high heart rate. A heart rate may be high because of exercise, stress, dehydration, infection, an arrhythmia, or another cause. Talk to your doctor if you have questions about your ECG recording.
Atrial Fibrillation	An Atrial Fibrillation result means the heart rate is between 50 and 99 beats per minute (bpm) and is beating irregularly. If you have not been diagnosed with AFib before, you should talk to your doctor.
Atrial Fibrillation - High Heart Rate	An Atrial Fibrillation — High HR result means your heart rate is beating between 100 and 150 beats per minute and is beating with an irregular pattern. If you have not been diagnosed with AFib before, you should talk to your doctor.
Inconclusive	An inconclusive result means the recording can’t be classified. This can happen for many reasons:  Heart rate is 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 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 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 the right gestures to be adopted and those to be avoided. Signs of other arrhythmia: This sensor is capable of detecting atrial fibrillation, but is not able to diagnose other types of arrhythmias. This recording cannot be classified as normal rhythm or atrial fibrillation.
Poor Recording	A Poor Recording result means the recording quality is low and the ECG cannot be classified. Some things that can cause this type of result are: Excessive movement that causes a signal of poor quality Proximity to an electrical device that generates strong electromagnetic fields Not following best practices for gestures to be adopted A small percentage of people may have certain physiological conditions that prevent them from creating enough signal to produce a quality recording.    You may try to re-record your ECG. You can review how to take an ECG during setup or by tapping Take a Recording in the ECG section of the Withings app on your smartphone. If you think you may be having a heart attack (myocardial infarction) or are facing a medical emergency, call the emergency services.

Note that atrial fibrillation can be episodic rather than continuous. This can cause the algorithm used by ScanWatch 2 to fail for some types of arrhythmia other than atrial fibrillation, particularly in the case of extrasystole (a premature beat of one of the heart's chambers which leads to momentary arrhythmia). With the ScanWatch 2's medical-grade graph, a cardiologist can provide you with a more accurate diagnosis.

If you receive an undefined result due to a poor recording, you might try to re-record your ECG. Click here for more information.

If you encounter issues with your ECG recordings, click here.

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