Atrial Rhythms

Premature Atrial Complex ECG Interpretation

Intro to PACs

PACs can occur for a number of different reasons i.e., diet, fatigue, stress, disease, ischemia to name a few.
Premature complexes frequently occur in bradycardic rhythms, but may occur almost any time.
PACs occur when an early electrical impulse occurs from a location in the atria other than the SA node.

This early impulse causes an early cardiac complex which disrupts the underlying rhythm.
The locus of stimulation being different, results in a change in the morphology of the P wave.
PACs can occur occasionally or frequently.
PACs ECG can be observed with or without a pattern
The P wave with PAC's will always be upright

Notice the following: the R to R interval is irregular, the fifth complex is early and the P wave on the early complex is a different shape.

Analyze this tracing using the five steps of rhythm analysis.

Show Answer

Authors and Sources

Electrocardiography for Healthcare Professionals, 6th Edition Kathryn Booth and Thomas O'Brien
ISBN10: 1265013470, ISBN13: 9781265013479
McGraw Hill, 2023
Rapid Interpretation of EKG's, Sixth Edition
Dale Dublin
Cover Publishing Company
EKG Reference Guide
EKG.Academy
12 Lead EKG for Nurses: Simple Steps to Interpret Rhythms, Arrhythmias, Blocks, Hypertrophy, Infarcts, & Cardiac Drugs
Aaron Reed
Create Space Independent Publishing
Heart Sounds and Murmurs: A Practical Guide with Audio CD-ROM 3rd Edition
Elsevier-Health Sciences Division
Barbara A. Erickson, PhD, RN, CCRN
The Virtual Cardiac Patient: A Multimedia Guide to Heart Sounds, Murmurs, EKG Jonathan Keroes, David Lieberman
Publisher: Lippincott Williams & Wilkin)
ISBN-10: 0781784425; ISBN-13: 978-0781784429
Project Semilla, UCLA Emergency Medicine, EKG Training Breena R. Taira, MD, MPH
ECG Reference Guide
PracticalClinicalSkills.com