Fundamentals of Heart Sounds

Normal Heart Sounds Lesson

Where to Auscultate

patient thorax when auscultating by stethoscope

The patient was supine during auscultation.

Description

The closure of the mitral and tricuspid valves creates the first heart sound. The mitral valve usually closes first, immediately followed by the tricuspid valve. Closure of the aortic and pulmonic valves creates the second heart sound.

This recording is a normal first and second heart sound with a rate of sixty beats per minute. The stethoscope's diaphragm is positioned at the Apex (mitral valve area). Usually, the first heart sound is somewhat louder than the second heart sound when auscultating at the Apex. Sound intensity will vary with the chestpiece's position as well as with the patient's anatomy.

In addition to sound intensity, the first heart sound (S1) can be identified by its timing. At moderate heartbeat rates, the first heart sound follows the longer pause.

Phonocardiogram

Anatomy

Normal Heart Sounds

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

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
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