ECG Tutorial   
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Heart Rate
PR Interval
QRS Interval
QT Interval


To determine the heart rate.

Examine the distance between QRS complexes.

If the distances are regular, count the number of "little boxes" from the beginning of one QRS to the beginning of the next QRS complex. Divide the number of "little boxes" (which each represent 0.04 seconds) into 1500 to obtain the heart rate in beats per minute.

If the distances are irregular, count the number of QRS complexes, beginning at one QRS complex to the beginning of the last QRS complex within 30 large boxes (which each represent 0.2 seconds) and multiply by 10 to obtain the heart rate in beats/minute.

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