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Normal Second heart sound (Identify the abnormalities of S2)

The most difficult thing in auscultation is to identify the abnormalities of S2.

Physiology of Second heartsound
Two components for 2nd heart sound are- aortic and pulmonary

Aortic component it is the 1st component and loud one heard in all areas.

Pulmonary component - 2nd component and soft, heard only over pulmonary area.

Normal second heart sound
It is a high pitched sound with normal split - 2 components are separately heard during inspiration and as single component during expiration over the pulmonary area.
Distance between the 2 components during inspiration is 0.04 sec, during expiration is 0.02 sec. Human ear can appreciate, when the distance between the 2 components is 0.03 or more. Normal second heart sound is expressed as - normal in intensity and normal split with respiration.

Things to look for in S2:
A2 heard over aortic area and pulmonary area and the apex.
P2 heard over pulmonary area and 2-4 LICS only and not at the apex.
P2 heard over the apex only in pulmonary artery hypertension and in young.
Best site for S2 in COPD - epigastrium.