First Degree Heart Block ECG Interpretation
- First Degree Heart Block will look like a typical sinus rhythm with one distinguishing feature.
- The P-R interval will be constant throughout the tracing and measure greater than 0.20 seconds.
- Rate, regularity, P wave morphology and QRS duration and morphology will be unaffected.
- NOTE: The rate will be that of the underlying rhythm. If the rate is “normal”, it will be 60 – 100 bpm. If it is bradycardia, the rate will be less than 60 bpm.
- First Degree Heart Block is the most common heart block.
- People are born with it every day. They will likely live a long and healthy life and die from some other malady.
- Patients who develop a heart block during an MI bear close observation. This must be reported to the licensed healthcare practitioner immediately.
Notice the following: the only abnormality when analyzing this tracing is the abnormal duration of the P-R interval.
Analyze this tracing using the five steps of rhythm analysis.
- Rhythm: Regular
- Rate: 68
- P Wave: Upright
- PR interval: 0.28 sec
- QRS: 0.08 sec
- Interpretation: First Degree Heart Block
Authors and Sources
Authors and Reviewers
- ECG heart rhythm modules: Thomas O'Brien.
- ECG monitor simulation developer: Steve Collmann
12 Lead Course: Dr. Michael Mazzini, MD.
- Spanish language ECG: Breena R. Taira, MD, MPH
- Medical review: Dr. Jonathan Keroes, MD
- Medical review: Dr. Pedro Azevedo, MD, Cardiology
- Last Update: 11/8/2021
Electrocardiography for Healthcare Professionals, 5th Edition
Kathryn Booth and Thomas O'Brien
ISBN10: 1260064778, ISBN13: 9781260064773
McGraw Hill, 2019
Rapid Interpretation of EKG's, Sixth Edition
Cover Publishing Company
12 Lead EKG for Nurses: Simple Steps to Interpret Rhythms, Arrhythmias, Blocks, Hypertrophy, Infarcts, & Cardiac Drugs
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