Electrocardiogram

An electrocardiogram (ECG or EKG) is a noninvasive test used to measure electrical activity in the heart. Electrical sensors called leads are attached to predetermined positions on the arms, legs, and chest to record electrical activity and help assess heart function.

The ECG creates a graph that represents the normal phases of activation of the heart. When patients hearts beat normally in sinus rhythm, separate little bumps and lines indicate when the atria contract and when the ventricles contract. In patients with atrial fibrillation, the bumps showing organized contraction of the atria are no longer present. Instead, there are irregular, squiggly lines.

The ECG can also suggest recent or past heart attack, inflammation of the pericardium, or a blood clot that has traveled to the lungs. Electrocardiogram may be used in the diagnosis of atrial fibrillation, congestive heart failure, and heart attack.