CARDIAC CYCLE

•S1 begining of systole → Mitral & Tricuspide closure

•S2 begining of diastole.→ Aortic & Pulmonary closure  Variation with Respiration (P2 separates away from A2 b/c more blood is comming into the rigth heart, so the valve closes a little bit later). 
•S3 occurs in early diastole during rapid ventricular filling (after MV opens). Associated with ↑ filling pressures commonly in dilated ventricles (vol overloaded). Normal in kids and pregnant♀.
•S4 occurs in late diastole. Associated with ventricular hypertrophy (concentric HPY). High atrial pressure (Left atrium must push against stiff LV).

○ Aortic Stenosis → EC (when AV opens)
○ Mitral Prolapse → MC (sudden tensing of chordae tendinae)
○ Mitral Stenosis → OS (tensing of chordae tendinae.
EC= Ejection click, MC= Midsystolic click, OS= Opening snap
Heart Sounds
Auscultation Assistant

Type	Inspiration	Expiration	Cause
Normal or physiologic