Pharmacologic resolution of functional outflow tract obstruction after mitral valve repair.

A 74-year-old woman with mitral regurgitation secondary to ruptured chordae tendineae, complicated by a cleft in the posterior mitral leaflet and a severely calcified mitral annulus, underwent mitral valve repair by implantation of polytetrafluoroethylene chords and closure of the cleft, without the use of an annuloplasty ring. Immediately after the repair severe left ventricular outflow tract obstruction developed secondary to the systolic anterior motion of the mitral valve. Echocardiography identified the cause as functional, in the presence of a hypertrophic left ventricle with no significant preoperative intraventricular dynamic gradient. The obstruction was severe enough to render impossible the weaning of the patient from cardiopulmonary bypass. This problem was reversed by the infusion of beta-blocking agents into the extracorporeal circuit.