Third Heart Sound - Physiologic

Virtual Auscultation

patient torso with stethoscope chestpiece
patient position during auscultation

The patient's position should be supine.

Lesson

The third heart sound is heard early in diastole. Along with the first and second heart sounds, this extra sound creates a gallop cadence and sounds like "Kentucky." In this auscultation example the second heart sound is unsplit to make it easier for you to distinguish the third heart sound. The third heart sound is very low frequency (between 25Hz and 50Hz). Listen with the bell of the stethoscope at the cardiac apex. Asking the patient to lie on his left side will frequently increase the intensity of the third heart sound. A third heart sound is heard on occasion in normal individuals with no cardiac pathology.

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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