An EKG shows:

• How fast your heart is beating
• Whether the rhythm of your heartbeat is steady or irregular
• The strength and timing of electrical signals as they pass through each part of your heart

This test is used to detect and evaluate many heart problems, such as heart attack, arrhythmia (ah-RITH-me-ah), and heart failure. EKG results also can suggest other disorders that affect heart function.

ECGs also are used to monitor how the heart is working. This article focuses on how ECGs are used for testing purposes.