23 Heart Sounds

• 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

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

Persistent

• 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

• 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

• 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

S3

• quick moving blood hits wall

• pt lie on left side on exam table
• Kentucky

• between s2 and s1 is diastole

• 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

• 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