ACUTE AORTIC OUTFLOW OBSTRUCTION BY DIMINUTION OF BULBOVENTRICULAR FORAMEN SIZE AFTER VOLUME UNLOADING IN UNIVENTRICULAR PHYSIOLOGY

A young child with {S, L, L} segmental anatomy, double-inlet left vent ricle, transposition of the great arteries, rudimentary right ventricl e, and mildly restrictive bulboventricular foramen is reported, in who m intraoperative temporary snaring of the modified Blalock-Taussig shu nt resulted in instantaneous and dramatic volume contraction of the le ft ventricle, decrease in bulboventricular foramen size, and increase of the gradient across the latter from 10 mm Hg preoperatively to 50 m m Hg, A modified Damus-Stansel-Kaye procedure using autogenous aortic tissue resulted in unobstructed aortic outflow; in addition, a bidirec tional cavopulmonary shunt was performed. The importance of early reli ef of actual or potential aortic outflow obstruction in hearts with re strictive bulboventricular foramen is emphasized.