S1 Heart Sounds Introduction.

Introduction

Learn about the S1 heart sound, listen to examples, take short lessons and compare to other heart sounds. For all medical professionals.

Our S1 heart sound lessons can be found in this first heart sounds module. In addition, our reference index is designed to provide quick access to first heart sounds, with audio tracks, listening guides and waveforms. Use this link for quick reference to heart and lung sounds.

What is an S1 Heart Sound?

S1 heart sound is a low frequency sound, occurring at the beginning of systole. S1 can be best heard over the apex, using a stethoscope's bell or diaphragm. The first heart sound is caused by turbulence created when the mitral and tricuspid values close. S1 and S2 heart sounds are often described as lub - dub.

S1 Heart Sound Caused By

The S1 heart sound is caused by blood flow turbulence when mitral and tricuspid valves close at the start of systole.

Best Heart Position During Auscultation

Because S1 heart sounds occur when the mitral and tricuspid valve close, the best heart is locations for the stethoscope chestpiece are at the tricuspid (left lower sternal border) and mitral (cardiac apex) locations.

Listen

Listening Tips

Audio Playback

patient thorax when auscultating by stethoscope

The patient was supine during auscultation.

Waveform

Compare To S1 Decreased Intensity

The patient was supine during auscultation.

Heart Sounds Reference Guide

Our auscultation reference guide provides quick access to this sound as well as many other adventitious sounds. Each sound is described also with an audio recording and waveform.

Heart Sounds Reference Guide

Authors and Reviewers

Heart sounds by Dr. Jonathan Keroes, MD and David Lieberman, Developer, Virtual Cardiac Patient.
Reviewed by Dr. Barbara Erickson, PhD, RN, CCRN.
Last Update: 11/9/2021

Sources

Heart Sounds and Murmurs Across the Lifespan (with CD) Dr Barbara Ann Erickson
Publisher: Mosby
ISBN-10: 0323020453; ISBN-13: 978-0323020459
Heart Sounds and Murmurs: A Practical Guide with Audio CD-ROM 3rd Edition
Elsevier-Health Sciences Division
Barbara A. Erickson, PhD, RN, CCRN
How to measure blood pressure using a manual monitor
Mayo Foundation for Medical Education and Research (MFMER)
Heart and Lung Sounds Reference Guide
PracticalClinicalSkills.com
Manual Blood Pressure Measurement
Vital Sign Measurement Across the Lifespan