Partially unroofed coronary sinus in an infant with pulmonary vein stenosis: mixed blessing.

Transcatheter intervention on the pulmonary vein often requires performing transseptal puncture, which is a risky procedure. We describe a rare association of a partially unroofed coronary sinus with pulmonary vein stenosis causing desaturation in a young infant where the presence of the unroofed coronary sinus allowed for a novel interventional approach to the stenotic left pulmonary vein, avoiding the high risk of transseptal puncture.