QRS - EKG Basics.


The QRS complex indicates ventricular depolarization. Depolarization triggers contraction of the ventricles.

Because of the larger tissue mass, the QRS complex is larger than the P wave. While the prototypical QRS complex consists of three wave components, one or two of these components may be missing.

In this step, measure the QRS interval from the end of the PR interval to the end of the S wave. Use calipers, marking paper or by counting small boxes. Normally this interval is 0.06 to 0.12 seconds (1.5 to 3 boxes).

ekg QRS Interval



Authors and Reviewers

Authored by Thomas O'Brien
Medically reviewed by Dr. Jonathan Keroes, MD, Cardiology
Last Update: 11/8/2020



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