Second Heart Sound - Splitting | Reference #119

This lesson covers physiologic and paradoxical splitting of the second heart sound. The second heart sound (S2) is created by the closing of the aortic valve and the closing of the pulmonic valve. The difference in timing between the closure of the aortic and pulmonic valves creates a split second heart sound. Careful analysis of the splitting and intensity of the second heart sound can indicate the presence of many cardiac abnormalities. In this example splitting varies between zero and eighty milliseconds depending on the phase of the respiratory cycle. In physiologic splitting the maximum separation between aortic and pulmonic components of the second heart sound occurs at peak inspiration. In paradoxical splitting the maximum separation occurs at peak expiration. Paradoxical splitting can occur with left bundle-branch block (LBBB) and aortic stenosis both of which cause the aortic valve closure to be delayed until after the pulmonic valve closure, reversing the normal sequence of events.

Second Heart Sound - Splitting Audio

Second Heart Sound - Splitting auscultation sound from lesson
waveform

Technique

Patient position
The patient's position should be supine.

Auscultation Tips

S2:Splitting during inspiration

Sound Wave



Observe Cardiac Animation

Authors and Sources

Authors and Reviewers


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
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Second Heart Sound - Splitting | Reference #119




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