This rarely develops into Eisenmenger’s syndrome if pulmonary hypertension develops reversing the direction of the shunt ... sinus venosus defect 3 = Ostium secundum atrial septal defect 4 ...

When this pulmonary hypertension is severe enough, the direction of shunt reverses ... venosus defect 2 = Lower sinus venosus defect 3 = Ostium secundum atrial septal defect 4 = Coronary sinus ...

Diagnosing a secundum ASD is more often than not incidental because ... although small residual shunts, which are not hemodynamically significant, may be observed in the immediate postclosure ...