Flail mitral valve usually causes severe mitral regurgitation, which may lead to left ventricular dysfunction if left uncorrected. The authors present a case of flail posterior mitral valve leaflet and severe mitral regurgitation in which mitral valve adaptation led to enlargement of the anterior mitral valve leaflet, decrease in mitral regurgitation, and reverse left ventricular remodeling without any need for surgery.
A 39-year-old man presented in 1999 with asymptomatic severe mitral regurgitation (MR) due to a flail mitral valve (MV). His left ventricular (LV) end-diastolic diameter was 5.4 cm at that time. Repeat echocardiography 6 months later, in 2000, showed a moderately dilated left ventricle (LV end-diastolic diameter, 6.3 cm; LV end-diastolic volume, 249 cm 3 ), with normal systolic function (ejection fraction, 67%) and a flail posterior MV leaflet with ruptured chordae to the middle scallop of the posterior leaflet ( Figures 1 and 2 , [CR] ). He had severe MR, with systolic flow reversal in his right pulmonary vein and an effective regurgitant orifice area of 0.84 cm 2 ( Figures 3 and 4 , [CR] ). The left atrium was severely enlarged (left atrial volume, 178 cm 3 ), and estimated systolic pulmonary artery pressure was 35 mm Hg.
The patient was treated with ramipril 5 mg/d, which was later replaced with candesartan 8 mg/d. During follow-up, MR spontaneously decreased, LV end-diastolic diameter gradually decreased to 5.3 cm, and LV end-diastolic volume decreased to 164 cm 3 . Echocardiography performed in 2009, 10 years after his presentation, showed a normal-size left ventricle, moderate MR, and normal pulmonary venous flow, with an effective regurgitant orifice area of 0.19 cm 2 ( Figures 1-4 , Videos 3 and 4 ). Left atrial volume had decreased to 78 cm 3 , and systolic pulmonary artery pressure had decreased to 21 mm Hg. The most significant findings were that the length of his anterior MV leaflet had increased from 2.5 cm in 2000 to 2.9 cm in 2009 and that his mitral annular diameter had decreased from 4.5 to 4 cm ( Figures 1 and 2 ). This resulted in better occlusion of the MV orifice in systole, with the anterior MV leaflet reaching the posterior MV annulus and compensating for the lack of a functional posterior leaflet in the region of the middle scallop.