23 Heart Sounds

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• S1: closure of MV, LV > LA

• S2: closure of AV, LV < aortic pressure

• S1: QRS, depolarization of ventricles, contract, close mitral and tricuspid valves

• S2: aortic closes first

Splitting

Physiologic

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• inspiration: increased venous return to RV, longer for RV to pump blood, delays PV closure

Persistent

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• exhalation: some separation of aortic and pulmonic components of S2, increases with inspiration, doesn't go away in exhalation

• RBBB: delayed contraction of RV, even during exhalation, PV closure late

• PHTN: dilated RV, delayed closure of PV even during exhalation

• anything delays contraction of RV: electrical (RBBB) or structural (dilated)

Fixed

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• ASD: blood from left to right, always have increased venous return to right, even during exhalation

• doesn't change in size during exhalation/inspiration, different from persistent

• child with shortness of breath and fixed split S2 = ASD

Paradoxical

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• split during exhalation and single during inhalation

• exhalation: AV closure delayed

• inhalation: venous return delays PV closure, single heart sound

• pacemaker: signal to RV first, delayed left closure

• HCM: blockage to flow from thickened septum

Pathologic

P2

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S3

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• quick moving blood hits wall

• pt lie on left side on exam table

• Kentucky

• between s2 and s1 is diastole

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• slams blood hitting stiff wall and making a loud noise, requires atrial kick, can't occur in afib

• Tennessee

• between s2 and s1 is diastole

Clicks

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• sound like click and in systole

• normal: leveled plane

• MVP: leaflets bellow up into LA, leaflets damaged and stretched, cause click when leaflets snap up into LA like a parachute, small amount of mitral regurge after click

• click and holosystolic: sounds like mitral regurge with S3