Partially unroofed coronary sinus associated with tricuspid atresia. An important associated lesion in the Fontan operation.

A case of tricuspid atresia associated with partially unroofed coronary sinus following a Fontan operation is described. A 4-year-old boy with tricuspid atresia showed persistent arterial desaturation immediately after a modified Fontan operation. At reoperation on the next day, a partially unroofed coronary sinus was recognized and repaired through a left atriotomy. Although uncommon, this associated anomaly should be kept in mind even in the absence of a persistent left superior vena cava and should be suspected if arterial desaturation occurs after a modified Fontan operation.