Third Heart Sound Lesson #635
The patient was supine during auscultation.
Description
A third heart sound (S3) occurs early in diastole, just after the second heart sound. S3 is a low-frequency sound best heard using the bell of the stethoscope pressed lightly on the skin of the chest. Position the chestpiece at the left lateral sternal border (LLSB) or xiphoid area.
Sudden deceleration of blood flow into the left ventricle from the left atrium causes the third heart sound. In the anatomy video, observe the thin-walled, dilated left ventricle with generalized decreased vigor of contraction.
In the presence of a third heart sound (S3), the first heart sound decreases in intensity while the second heart sound increases in intensity
In young people and athletes, it is a normal phenomenon. In older individuals, it indicates the presence of heart disease.
Phonocardiogram
Anatomy
Third Heart Sound
Authors and Sources
Authors and Reviewers
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Heart sounds by Dr. Jonathan Keroes, MD and David Lieberman, Developer, Virtual Cardiac Patient.
- Lung sounds by Diane Wrigley, PA
- Respiratory cases: William French
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David Lieberman, Audio Engineering
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Heart sounds mentorship by W. Proctor Harvey, MD
- Special thanks for the medical mentorship of Dr. Raymond Murphy
- Reviewed by Dr. Barbara Erickson, PhD, RN, CCRN.
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Last Update: 11/10/2021
Sources
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Heart and Lung Sounds Reference Library
Diane S. Wrigley
Publisher: PESI -
Impact Patient Care: Key Physical Assessment Strategies and the Underlying Pathophysiology
Diane S Wrigley & Rosale Lobo - Practical Clinical Skills: Lung Sounds
- Essential Lung Sounds
Diane S. Wrigley, PA-C
Published by MedEdu LLC - PESI Faculty - Diane S Wrigley
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Case Profiles in Respiratory Care 3rd Ed, 2019
William A.French
Published by Delmar Cengage - Essential Lung Sounds
by William A. French
Published by Cengage Learning, 2011 - Understanding Lung Sounds
Steven Lehrer, MD
- Clinical Heart Disease
W Proctor Harvey, MD
Clinical Heart Disease
Laennec Publishing; 1st edition (January 1, 2009) -
Heart and Lung Sounds Reference Guide
PracticalClinicalSkills.com
