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Premature Atrial Complex | Reference Guide

EKG Strip

ecg rhythm strip for reference guide

EKG Features

Rate: Usually normal but depends on underlying rhythm
Rhythm: Irregular
P Wave: Premature, positive and shape is abnormal
PR Interval: Normal or longer
QRS: 0.10 sec or less
This early impulse causes an early cardiac complex which disrupts the underlying rhythm.
Premature atrial contractions are a common arrhythmia with early beats. PACs are caused by ectopic atrial sites firing an electrical signal before the next normal SA node fires. PACs can occur in healthy young and elderly patients. Premature atrial contractions are also called premature atrial complexes.
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Authors and Reviewers

Authored by Thomas O'Brien
EKG tracings reviewed by Dr. Pedro Azevedo, MD, Cardiology
Medically reviewed by Dr. Jonathan Keroes, MD, Cardiology
Last Update: 11/8/2021


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