An electrocardiogram (ECG or EKG) is a diagnostic test that measures the electrical activity of the heart. It records the heart's rhythm and electrical impulses, providing valuable information about its health and function. During an ECG, electrodes are placed on the chest, arms, and legs, which detect the electrical signals produced by the heart as it beats. These signals are then displayed on a monitor or printed onto paper in the form of waves, representing different phases of the cardiac cycle. By analyzing the ECG waveform patterns, healthcare professionals can identify various heart conditions, including arrhythmias, heart attacks, and abnormalities in the heart's structure. ECGs are non-invasive, painless, and quick, making them a widely used tool in both routine check-ups and emergency situations to assess cardiac health and guide treatment decisions.