ECG Tutorial   
line11.gif (1202 bytes)


Heart Rate
PR Interval
QRS Interval
QT Interval


To determine the PR interval.

The PR interval is the time in seconds from the beginning of the P wave to the beginning of the QRS complex. It corresponds to the time lag from the onset of atrial depolarization to the onset of ventricular depolarization. This time lag allows atrial systole to occur, filling the ventricles before ventricular systole. Most of the delay occurs in the AV node. The PR interval is longer with high vagal tone. A prolonged PR interval corresponds to impaired AV conduction.

Copyright 1999 University of Pennsylvania School of Veterinary Medicine
Faculty Sponsor: Dr. Virginia Reef
Student: Jeff Horst  V'02
Date this page was last updated: July 29, 2002