Why is alcohol used to wipe the skin when performing an electrocardiogram?

Alcohol is used to wipe the skin before an electrocardiogram (ECG) primarily to improve electrical conductivity and enhance the machine's sensitivity.

An electrocardiogram is a technique that uses an ECG machine to record, from the body surface, the electrical activity of the heart during each cardiac cycle. When patients experience symptoms such as irregular heartbeat, palpitations, chest tightness, or shortness of breath, an ECG can help detect possible cardiac abnormalities. During the procedure, doctors commonly use alcohol to clean the skin at electrode placement sites. This helps remove surface impurities, ensures good contact between the electrodes and the skin, improves skin conductivity, enhances transmission of cardiac signals to the recording device, and ultimately improves the quality of the ECG results.

It is important to lie flat, keep all muscles relaxed, breathe steadily, remain quiet, and avoid changing body positions or speaking loudly during the ECG. Additionally, patients should avoid eating large meals, smoking, or drinking alcohol prior to the test, as these may interfere with the accuracy of the ECG results.