Normal Heart Sounds

Physiologic Third Heart Sound Lesson #656

patient thorax when auscultating by stethoscope

The patient was supine during auscultation.

Description

The third heart sound (S3) can be heard early in diastole. Along with the first and second heart sounds, this extra sound creates a gallop cadence and sounds like Kentucky. The second heart sound is unsplit in this recording so that S3 is easier to hear.

Use the stethoscope bell at the apex because the third heart sound has a very-low frequency. If the patient lies on her left side, S3 will usually be louder.

The third heart sound is normal in children and young adults. Women lose S3 in their thirties, while men lose S3 in their twenties. After these ages, S3 can indicate heart disease, except for adults active in sports or fitness.

Phonocardiogram

Anatomy

Physiologic Third Heart Sound

Authors and Sources

Authors and Reviewers

Heart sounds by Dr. Jonathan Keroes, MD and David Lieberman, Developer, Virtual Cardiac Patient.
Lung sounds by Diane Wrigley, PA
Respiratory cases: William French
David Lieberman, Audio Engineering
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.
Last Update: 11/10/2021

Sources

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
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