Sounds: S2 Heart

Three major abnormal patterns are clinically significant:

1. Introduction The second heart sound (S2) is produced by the closure of the semilunar valves (aortic and pulmonary) at the beginning of ventricular diastole. It marks the end of systole. Unlike the first heart sound (S1), which is monophonic, S2 is normally split into two audible components: A2 (aortic valve closure) and P2 (pulmonary valve closure). Analysis of S2—its intensity, splitting pattern, and pitch—provides critical diagnostic information about hemodynamics and valvular function. s2 heart sounds

In Atrial Septal Defect (secundum type), chronic right ventricular volume overload prolongs RV systole. The split becomes "fixed" because respiration cannot further alter the already maximal delay of P2. which is monophonic