Explain Fixer1 Split S in second heart ?

A2P2 interval is wide and persistent and doesn't change during respiratory cycle. It is an auscultatory hallmark of uncomplicated ostium secondly ASD.

In ASD, the P, moves with inspiration only due to increased RV volume, as there is significant-impendence effect when lung vessels are overfilled due to shunt flow. The A, may either not move at all or move in same direction as P, during inspiration because the LV doesn't become smaller. It may become larger because increased blood volume is RA will increase RA pressure and thereby reduce left to right shunt.