An electrocardiogram, or ECG, is a simple test that records the electrical activity of the heart. It uses small sticky patches called electrodes placed on the skin to detect heartbeats. The ECG machine then creates a graph that shows how fast the heart beats and whether the heart's rhythm is normal. This information helps doctors understand how well the heart is functioning. Doctors often use an ECG to diagnose various heart conditions, such as arrhythmias or heart attacks. The test is quick, painless, and can provide valuable insights into a person's heart health, making it an essential tool in cardiology.