Electrocardiogram (EKG) Components and Intervals
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 is a record of the electrical activity through the upper heart chambers (atria).
- The QRS complex is a record of the movement of electrical impulses through the lower heart chambers (ventricles).
- The ST segment shows when the ventricle is contracting but no electricity is flowing through it. The ST segment usually appears as a straight, level line between the QRS complex and the T wave.
- The T wave shows when the lower heart chambers are resetting electrically and preparing for their next muscle contraction.
|Primary Medical Reviewer||E. Gregory Thompson, MD - Internal Medicine|
|Specialist Medical Reviewer||John M. Miller, MD - Electrophysiology|
|Last Revised||April 4, 2011|