Case Presentation

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.

Transthoracic echocardiography using the apical 4-chamber view. Diastolic MV annular diameter decreased from 4.5 cm in 2000 to 4 cm in 2009. Arrow indicates anterior MV leaflet; arrowhead indicates flail posterior MV leaflet.

Transthoracic apical long-axis view. The length of the unstretched anterior MV leaflet (arrow) in diastole increased from 2.5 cm in 2000 to 2.9 cm in 2009. In 2009, the tip of the anterior MV leaflet reached the posterior MV annulus in systole, leading to better occlusion of the MV orifice.

Color flow Doppler using the apical 4-chamber view (top) and the apical long-axis view (bottom) showing an anteromedially directed MR jet. There was severe MR in 2000 and only moderate MR in 2009.

(Top) Right pulmonary venous (PV) flow showing systolic flow reversal in 2000 and normal systolic forward flow in 2009. (Bottom) Color flow Doppler with baseline shift showing the flow convergence zone. The effective regurgitant orifice (ERO) was calculated using the proximal isovelocity surface area (PISA) method. The radius (r) of the PISA and the ERO significantly decreased from 2000 to 2009.

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.