The dicrotic notch on the aoic pressure curve is caused by-
dichrotic notch is a small dip in the graph of aoic pressure throughout the cardiaccycle corresponding to the closure of aoic valve Ref Harrison 20th edition pg 1445
Closure of the pulmonary valve
Rapid filling of the left ventricle
Closure of the aoic valve
Contraction of the atria
C.V.S