Electrocardiography (EKG, ECG) tracings show a characteristic pattern of electrical impulses that are generated by the heart. The different parts of an EKG tracing of a heartbeat are called the P wave, the QRS complex, the ST segment, and the T wave. See an illustration of an electrocardiography tracing.
- The P wave is a record of the movement of electrical activity through the upper heart chambers (the atria) and is recorded when they contract.
- The QRS complex is a record of the movement of electrical impulses through the lower heart chambers (the ventricles) and is recorded when they contract.
- The ST segment appears as a straight, level line between the QRS complex and the T wave. Elevated or lowered ST segments may mean the heart muscle is damaged or not receiving enough blood.
- The T wave corresponds to the period when the lower heart chambers are relaxing and preparing for their next muscle contraction.
See an illustration of EKG components and intervals.
Credits
| Author | Robin Parks, MS |
| Editor | Kathleen M. Ariss, MS |
| Associate Editor | Pat Truman |
| Associate Editor | Terrina Vail |
| Primary Medical Reviewer | Caroline S. Rhoads, MD - Internal Medicine |
| Specialist Medical Reviewer | Stephen Fort, MD, MRCP, FRCPC - Interventional Cardiology |
| Last Updated | September 1, 2006 |
Author:Robin Parks, MS
Last Updated: 09/01/2006
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