Discussion

Tetralogy of Fallot with aortopulmonary window causes heart failure secondary to large left to right shunt distal to the stenosed pulmonary valve. ^{Reference Alborino, Guccione, Di Donato and Marino1} This can present in the newborn period if the defect is large, and the pulmonary vascular resistance falls rapidly. The diagnosis can easily be mistaken for a common arterial trunk as the pulmonary valve is commonly atretic or is very hypoplastic. The resemblance to the common arterial trunk is accentuated by the presence of doubly committed ventricular septal defect with absence of conal septum beneath the pulmonary valve. In our case, it was difficult to image the hypoplastic pulmonary annulus as it had a peculiar horizontal lie over a doubly committed ventricular septal defect with absent conal septum (Fig 1b).

Surgical management consisted of repairing the aortopulmonary window first through trans-window approach. This was followed by intracardiac repair with transannular patch. Our institutional policy is to perform monocusp reconstruction of the pulmonary valve after transannular patch, and it was particularly beneficial in this case as pulmonary artery pressure was higher than that for a usual tetralogy of Fallot and pulmonary regurgitation in this situation is more likely to cause post-operative right ventricular failure.

Less than 20 such cases have been reported in literature with association of pulmonary atresia being commoner than pulmonary stenosis. Poor prognosis has been noted in cases with delayed diagnosis. The case is of educational value as aortopulmonary window is rarely considered as a cause of heart failure in tetralogy of Fallot. The lesion can be easily missed on transthoracic echo, unless carefully looked for. Surgical repair yields excellent result and must be offered early to prevent pulmonary hypertensive changes. ^{Reference Kynta, Rawat, Thingnam, Manoj and Sharma2}