First and Second Heart Sounds - Normal and Unsplit

This is a normal first and second heart sound at 60 beats per minute. You are auscultating at the Mitral valve area (Apex). The first heart sound has slightly greater intensity than the second heart sound.

The first heart sound is produced by the closing of the mitral and tricuspid valve leaflets.
The second heart sound is produced by the closing of the aortic and pulmonic valve leaflets.
The second heart sound is unsplit when the subject is holding his or her breath at peak expiration.

Auscultation Sounds

Patient Recording

First and Second Heart Sounds - Normal and Unsplit

Patient Recording - Half Speed

Position

The patient's position should be supine.

Listening Tips

Waveform (Phonocardiogram)

Observe Cardiac Animation

The first heart sound is produced by the closing of the mitral and tricuspid valve leaflets. The second heart sound is produced by the closing of the aortic and pulmonic valve leaflets.

Authors and Sources

Authors and Reviewers

EKG heart rhythm modules: Thomas O'Brien.
EKG monitor simulation developer: Steve Collmann
12 Lead Course: Dr. Michael Mazzini, MD.
Spanish language EKG: Breena R. Taira, MD, MPH
Medical review: Dr. Jonathan Keroes, MD
Heart sounds and mentorship: W. Proctor Harvey, MD
Medical review: Dr. Pedro Azevedo, MD, Cardiology
Last Update: 1/8/2023

Sources

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

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