In atrial fibrillation, erratic electrical impulses in the upper chambers of the heart (atria) cause those chambers to fibrillate, or quiver. This results in an irregular and frequently rapid heart rate. The irregular pattern in the electrocardiogram (EKG, ECG) tracing shows these erratic impulses.
Last Revised: December 14, 2012
Author: Healthwise Staff
Medical Review: Rakesh K. Pai, MD, FACC - Cardiology, Electrophysiology & John M. Miller, MD, FACC - Cardiology, Electrophysiology
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