An electrocardiogram (EKG or ECG) is a recording of the heart’s electrical activity as a graph or series of wave lines on a moving strip of paper. This gives the physician important information about the heart. For example, it can show the heart's rate and rhythm. It can also detect decreased blood flow (cardiac ischemia), enlargement (hypertrophy) of the heart, or the presence of either current or past heart attacks.

EKGs are noninvasive, quick, safe, painless and inexpensive tests that are routinely done if a heart condition is suspected. Depending on what the results show, in combination with the patient’s medical history and a physical exam, the physician may order further tests or a combination of medications and lifestyle changes.

Patients may receive an EKG as part of a physical exam in a hospital, clinic or doctor’s office, but the test can be performed almost anywhere.