An EKG/ECG records electrical activity of the heart such as timing and duration of each phase of the heartbeat.
An ECG provides two important kinds of information. Firstly, by measuring time intervals on the test, a doctor can find out how long it takes an electrical wave to pass through the heart. This information shows if the activity is too normal or slow, fast or irregular. Next, the test tells doctors if parts of the heart are too large or overworked.
Learn more about diagnostic tests for the heart.