Major hemodynamic changes in DAPVF include left-to-left shunt and increased pulmonary venous pressure. The left-to-left shunt, which produces left parasternal systolic murmur over the fourth intercostal space at the same horizontal level as DAPVF, results in enlargement of the left atrium and left ventricle and, eventually, heart failure. Cardiac failure is the presenting feature in the only reported case of neonatal DAPVF.2 The other pathophysiologic change is elevated venous pressure of the involved pulmonary vein, which is largely due to the communication between the pulmonary vein and the descending aorta, thus providing a passage for retrograde perfusion of the lung parenchyma and blood drainage to the left atrium. Interestingly, pressure at the ostium of segmental veins varies with their specific positions. This was proved by preoperative angiography, which showed that the contrast agent entered the lower tributaries of the left inferior pulmonary vein, but not the tributaries of the superior segment. As a result, proliferating vessels covering different segments were dilated to various degrees, as seen in the operation. Persistently elevated venous pressure, varied at different venous segments, could lead to segmental, lobar, or lateral pulmonary arterial hypertension. Rupture of proliferating and dilated vessels of the basal segments secondary to elevation of pulmonary venous pressure likely underlay hemoptysis in our patient.