Physiologic Third Heart Sound Lesson #656

patient thorax when auscultating by stethoscope

patient position during auscultation
The patient was supine during auscultation.


The third heart sound (S3) can be heard early in diastole. Along with the first and second heart sounds, this extra sound creates a gallop cadence and sounds like Kentucky. The second heart sound is unsplit in this recording so that S3 is easier to hear.

Use the stethoscope bell at the apex because the third heart sound has a very-low frequency. If the patient lies on her left side, S3 will usually be louder.

The third heart sound is normal in children and young adults. Women lose S3 in their thirties, while men lose S3 in their twenties. After these ages, S3 can indicate heart disease, except for adults active in sports or fitness.



Physiologic Third Heart Sound

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