Flail mitral valve syndrome: comparison with chronic mitral regurgitation of other etiologies.

Thirty-nine patients with symptomatic severe mitral regurgitation (MR) were studied by cardiac catheterization and two-dimensional echocardiography (2DE) prior to mitral valve replacement. A flail mitral valve was found at surgery in 23 patients (group 1); 16 patients had intact chordae tendineae (chronic MR, group 2). No difference was found between groups 1 and 2 with regard to hemodynamic findings. Left atrial volumes in end systole (LAESV) and end diastole (LAEDV) were determined by 2DE from apical four- and two-chamber views with the use of a biplane area-length method and a light pen system. The LAESV and LAEDV measured 116 +/- 66 ml and 56 +/- 48 ml, respectively, in group 1, as compared with 185 +/- 101 ml and 105 +/- 62 ml in group 2 (p less than 0.025). Ten patients from group 1 with LAESV less than or equal to 100 ml (group 1A) were compared to the remaining 13 patients with LAESV greater than 100 ml (group 1B). Patients in group 1A had significantly smaller left ventricular volume and higher mean pulmonary wedge pressure, pulmonary artery, and left ventricular end-diastolic pressure compared to patients in groups 1B and 2 (p less than 0.05). Thus, a subset group of patients with flail mitral leaflets and smaller LAESV has hemodynamic features of acute MR, whereas the remainder with larger LAESV are indistinguishable from patients with chronic MR.