An electrocardiogram (ECG or EKG) measures the electrical signals that pass through the heart muscle. An ECG shows the rhythm and strength of the heart. It is used in routine physical exams whenever a heart disorder is suspected or when patients are taking certain drugs.

What does it tell the doctor?
This test shows whether you have any heart damage and where exactly that damage is. An ECG is also used to find abnormal heart rhythms and to monitor the effect of drugs.

What happens before the test?
There is no preparation before the test.

What will I experience?
The test is usually carried out while you are lying down and relaxing. A cool jelly or paste is put on small metal plates (much like a watchband) that are attached to your arms and legs. A jelly or lotion is applied to your chest. Then suction cup-like electrodes are attached to your chest. Patches similar to Band-Aids can be used instead of the plates and suction-cup electrodes. There is no discomfort involved, and the test is complete within 5-10 minutes. Occasionally, an ECG might be performed while the patient is walking on a treadmill.