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EKG components and intervals

Illustration copyright 2002 by Nucleus Communications, Inc. All rights reserved. http://www.nucleusinc.com

An electrocardiogram (EKG, ECG) translates the heart's electrical activity into line tracings on paper. The spikes and dips in the line tracings are called waves.

The P wave represents the electrical activity in the atria. The Q, R, and S waves-called the QRS complex-represent the electrical activity in the ventricles. The T wave represents the electrical recovery, or repolarization, of the ventricles.

Primary Medical Reviewer Caroline S. Rhoads, MD
- Internal Medicine
Specialist Medical Reviewer Stephen Fort, MD, MRCP, FRCPC
- Interventional Cardiology
Last Updated May 14, 2007

WebMD Medical Reference from Healthwise

Last Updated: May 14, 2007
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