An electrocardiogram (ECG or EKG) is a vital diagnostic tool in cardiology that measures the electrical activity of the heart over a period of time. This non-invasive test involves placing electrodes on the skin, typically on the chest, arms, and legs, to detect electrical signals produced by the heart as it beats. The resulting tracings provide detailed information about the heart's rhythm, rate, and electrical conduction pathways, making it indispensable for diagnosing a variety of cardiac conditions. An ECG can detect arrhythmias, heart attacks, and other cardiac abnormalities, enabling timely and accurate medical interventions. It is also used to monitor the effects of medications and the performance of devices such as pacemakers. Quick, painless, and relatively inexpensive, an ECG can be performed in various settings, including hospitals, clinics, and even ambulances, providing crucial data that can save lives and guide effective treatment plans.