First Heart Sounds

Fourth and First Heart Sounds Lesson #663

patient thorax when auscultating by stethoscope

The patient was supine during auscultation.

Description

A fourth sound gallop (S4) plus a first heart sound (S1) can mimic a split first heart sound. Since the S4 occurs just before the S1, it is easy to confuse a S4-S1 pair with a split S1.

Listen carefully to the frequency of the initial sound of the S4-S1 pair. If it is lower in frequency than the second sound, it is an S4. If the two sounds have a similar frequency, it is a split S1.

Phonocardiogram

Anatomy

Fourth and First Heart Sounds

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