First Heart Sound (Markedly Split)
If the splitting of the first heart sound is large (about 50 milliseconds), it is an indication of an abnormal condition called Right Bundle Branch Block. The splitting is most clearly heard at the tricuspid area. In the mitral valve area, the mitral component is louder. At 50 milliseconds, the splitting of the first heart sound is clearly audible.Auscultation Sounds
Position
The patient's position should be supine.
Listening Tips
S1:Splitting.Features:Auscultate this sound over tricuspid and mitral areas
Waveform (Phonocardiogram)
Observe Cardiac Animation
Authors and Sources
Authors and Reviewers
- EKG heart rhythm modules: Thomas O'Brien.
- EKG monitor simulation developer: Steve Collmann
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12 Lead Course: Dr. Michael Mazzini, MD.
- Spanish language EKG: Breena R. Taira, MD, MPH
- Medical review: Dr. Jonathan Keroes, MD
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Heart sounds and mentorship: W. Proctor Harvey, MD
- Medical review: Dr. Pedro Azevedo, MD, Cardiology
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Last Update: 1/8/2023
Sources
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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
Dale Dublin
Cover Publishing Company -
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 - Clinical Heart Disease
W Proctor Harvey, MD
Clinical Heart Disease
Laennec Publishing; 1st edition (January 1, 2009) -
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
First Heart Sound (Markedly Split) | #40
