An electrocardiogram (ECG or EKG) is a non-invasive diagnostic test used to measure the electrical activity of the heart. The test records the electrical signals produced by the heart as it beats, and generates a graph that shows the pattern of these signals.

During an ECG, small metal electrodes are attached to the skin on the chest, arms, and legs. The electrodes are connected to a machine that records the electrical activity of the heart. The test is painless and typically takes only a few minutes to complete.

ECGs are commonly used to diagnose and monitor various heart conditions, such as heart rhythm disorders, heart attacks, and other heart-related problems. The test is also used to monitor the effectiveness of certain heart treatments and to evaluate the health of the heart before surgery or other medical procedures.

Interpreting an ECG requires specialized training and expertise. A doctor or other qualified healthcare provider will typically review the ECG results and use them to make a diagnosis or determine the best course of treatment.