An Electrocardiogram (ECG or EKG) is a medical test that records the electrical activity of the heart. It helps diagnose heart conditions like arrhythmias, heart attacks, and other cardiac abnormalities. The test is quick, non-invasive, and painless, using electrodes placed on the skin to detect heart signals. ECGs are commonly used in hospitals, clinics, and ambulances to monitor heart health and guide treatment decisions.