First Heart Sound Page

Welcome to the first heart sound page. On this page we provide a definition, sample heart sounds and links to the training lessons available on this site.

What is an First Heart Sound?

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

Listen to First Heart Sound

First and Second Heart Sounds

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Normal first and second heart sounds.

Loud First Heart Sound

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Normal Heart Sound Guide

Information and examples of first and second hearts sounds. The guide pages provide waveforms with a moving cursor that is synchronized to the audio recording. In addition, listening tips are available.
Normal Heart Sounds

First Heart Sound Courses

This is a link to our short courses that cover first heart sounds.
Normal Heart Sounds
First Heart Sounds