In the normal heart, electrical impulses pace the rhythm at which the heart contracts and relaxes. The sinoatrial (SA) node triggers the electrical impulse, causing the upper chambers (atria) to contract. The signal travels through the atrioventricular (AV) node to the atrioventricular bundle, which divides into the Purkinje fibers. The fibers carry the signal and cause the lower chambers (ventricles) to contract.
The electrocardiogram (EKG, ECG) tracing above reflects this normal electrical activity.
ByHealthwise Staff Primary Medical ReviewerRakesh K. Pai, MD, FACC - Cardiology, Electrophysiology Specialist Medical ReviewerJohn M. Miller, MD, FACC - Cardiology, Electrophysiology
Current as ofMarch 12, 2014
WebMD Medical Reference from Healthwise
March 12, 2014
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