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Third Heart Sound Gallop Reference Guide

Third Heart Sound Gallop

A third heart sound occurs early in diastole. In young people and athletes it is a normal phenomenon. In older individuals it indicates the presence of congestive heart failure. The third heart sound is caused by a sudden deceleration of blood flow into the left ventricle from the left atrium. In the anatomy video you will see a thin-walled, dilated left ventricle with generalized decreased vigor of contraction. In the presence of a third heart sound (S3) the first heart sound is decreased in intensity while the second heart sound is increased in intensity. The third heart sound is a low frequency sound best heard with the bell of the stethoscope pressed lightly on the skin of the chest.

Auscultation Sound From Lesson

auscultation sound from lesson

Patient Recording

patient heart or lung sound
Third Heart Sound Gallop

Patient Recording - Half Speed Playback

patient heart or lung sound
Third Heart Sound Gallop


Patient position
The patient's position should be supine.

Listening Tips

S1:Reduced intensity
S2:Increased intensity
Diastole:S3 early in diastole, low-pitched, heard during expiration

Waveform (Phonocardiogram)

Observe Cardiac Animation

Authors and Sources

Authors and Reviewers


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Third Heart Sound Gallop | Description, Audio and Animations | #84
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