Which two heart conditions can lead to Eisenmenger's syndrome?

Eisenmenger's syndrome occurs as a result of long-standing left-to-right shunts that lead to pulmonary hypertension, ultimately causing a reversal of blood flow (right-to-left shunt). The conditions that typically lead to this syndrome include congenital heart defects that initially allow more oxygenated blood to flow to the lungs.

Atrial septal defect (ASD) allows blood to flow from the left atrium to the right atrium, leading to increased volume in the right heart and pulmonary circulation over time. Similarly, patent ductus arteriosus (PDA) allows blood to flow from the aorta back into the pulmonary artery, which can also increase pulmonary blood flow and pressure. Both of these conditions can create an overload situation that can eventually lead to pulmonary vascular disease and, if untreated, result in Eisenmenger's syndrome.

The other options include conditions that are either less likely to result in Eisenmenger's syndrome or do not create the same pathophysiological conditions required for the syndrome to develop.