Third Heart Sound

This presentation deals with significance and causes of third heart sound.

1. بسم الله الرحمن الرحیم

2. T hird H eart Sound significance

3. S3 Third heart sound (S 3) is produced in the ventricle due to abnormal filling pattern. It is a low-pitched sound heard at the end of rapid filling phase (early diastole). It occurs 0.14----0.22 seconds after the second heart sound. A third heart sound arising from the left ventricle is known as "left-sided third heart sound" and the one arising from right ventricle as "right-sided third heart sound ".

4. S3 S 3 is best heard with the bell of stethoscope. Left-sided S3 is best heard during expiration with the patient in the left lateral position. Right-sided S 3 is best heard during inspiration. Left-sided S3 may be physiological or pathological. Right-sided S3 is always pathological.

5. Causes of Third Heart Sound Physiological S3 Hyper dynamic States Pathological left-sided S3 Pathological right-sided S3 • Children • Under 40 years • Athletes • Pregnancy • AV fistula • Thyrotoxicosis • Left ventricular failure • Aortic regurgitation • Mitral regurgitation • lschaemic heart disease • Cardiomyopathy • Right ventricular failure