What is a 6-Lead 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.

An ECG lead is a direction along which one measures the voltage field created by the electrical activity of the heart. Thanks to the Withings ECG Monitor technology, Withings Body Scan records 6 leads of the ECG, each of them being a representation of the electrical activity of the heart along one direction in the body. This is done by measuring leads II and III using a set of three electrodes (two located on the handle and one integrated into the glass of the scale) and computing the remaining leads: I, aVL, aVR, aVF.

Figure 1: Representation of the measuring sites (colored points) and ECG leads as measured (blue) and computed (green).

Figure 2: Representation of the ECG leads and their corresponding angles referred to the horizontal axis.

What do practitioners look for in the ECG graph?

A normal ECG graph will show the time sequence of the excitation and relaxation of different parts of your heart by  the electric wave. There are 3 distinct patterns:

1. First wave: the "P wave"
   
   The graph shows a first electric wave as electricity excites the right and left upper chambers of your heart: the atria.
2. Next wave: the "QRS Complex"
   
   This second pattern shows electricity exciting the right and left bottom chambers of your heart: the ventricles.
3.  Final wave: the "T wave"
   
   The final wave represents the electrical recovery (or return to a resting state) of the ventricles. 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, overworked or dysfunctional heart.

Which conditions can the Withings ECG Monitor detect on your Body Scan?

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

What are the various results I can get from an ECG recording? 

	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 Withings ECG Monitor. 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. Some elite athletes may also have a low heart rate.
	High Heart Rate A High Heart Rate result means your heart is beating above 150 bpm. This recording cannot be classified by Withings ECG Monitor. 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.
	Sinus Rhythm A Sinus Rhythm result means your heart rate is between 50 and 99 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 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.
	Atrial Fibrillation An Atrial Fibrillation result means the heart rate is between 50 and 99 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 bpm and is beating with an irregular pattern. If you have not been diagnosed with AFib before, you should talk to your doctor.
	Poor Recording A Poor Recording result means the recording quality is low and the ECG cannot be classified. This may be caused by errors during the measurement.  Click here for more information of the causes of a poor recording and what you can do to improve your results.  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.
	Inconclusive An Inconclusive result means that the signal cannot be classified as Sinus Rhythm or Atrial Fibrillation, although the quality of the recording is good. This may be due to various conditions, including but not limited to other arrhythmias or other heart conditions. Click here for more information of the causes of an inconclusive recording and what you can do to improve your results.  Please talk to your doctor if you receive an inconclusive ECG recording.

Notes:

• If you have questions about your ECG recording, please talk to your doctor.
• If you encounter issues with your ECG recordings, click here. 
• 6-lead ECG recordings will only appear on the Withings Android and iOS versions but will not appear on the Web Dashboard.

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