Electrocardiogram: A recording of the electrical activity of the heart. Abbreviated ECG and EKG. An ECG is a simple, noninvasive procedure. Electrodes are placed on the skin of the chest and connected in a specific order to a machine that, when turned on, measures electrical activity all over the heart.
An EKG can help diagnose:
Abnormally fast or irregular heart rhythms.
Abnormally slow heart rhythms.
Abnormal conduction of cardiac impulses, which may suggest underlying cardiac or metabolic disorders.
Evidence of the occurrence of a prior heart attack (myocardial infarction).