In exams like DNB SS questions on ASD and VSD are common. Most cardiac surgery questions are here

Q) Most common ASD is 

a) Ostium Primum

b) Ostium Secundum

C) Sinus Venosus

d) All are equal

Answer 

b

Ostium Secundum

 

ASDs ■ Common defects Ostium secundum: fossa ovalis defect (approximately 70 per cent of ASDs) Ostium primum: atrioventricular septal defect (approx imately 20 per cent of ASDs) Sinus venosus defect: often associated with anomalous pulmonary venous drainage (approximately 10 per cent of ASDs) Patent foramen ovale: common in isolation, usually no left-to-right shunt (not strictly an ASD) Rarer defects Inferior vena cava defects: a low sinus venosus defect and may allow shunting of blood into the left atrium Coronary sinus septal defect: also known as unroofed coronary sinus with the left superior vena cava draining to the left atrium as part of a more complex lesion