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Third Heart Sound Gallop C31

Virtual Auscultation

patient torso with stethoscope chestpiece
patient position during auscultation

The patient's position should be supine.

Lesson

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.

Waveform





Heart Sounds Video



Authors and Reviewers

Authored by Dr. Jonathan Keroes, MD and David Lieberman, Developer, Virtual Cardiac Patient. Medically reviewed by Dr. Barbara Erickson, PhD, RN, CCRN. Last Update: 11/28/2021


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