Natural history of the flail mitral leaflet syndrome: A serial 2-dimensional echocardiographic study

Abstract

The syndrome of a flail mitral leaflet results in acute mitral regurgitation (MR). Twenty-nine patients with a flail mitral leaflet had serial 2-dimensional echocardiographic (2-D echo) examinations. Left ventricular (LV) and left atrial (LA) volumes and ejection fraction (EF) were obtained using a computerized light-pen system. Fifteen patients with the 2-D echo criteria of a flail mitral leaflet were treated medically and followed for a mean of 19 months. Eleven patients did not undergo surgery (Group IA). Four patients initially were treated medically, but ultimately required surgery (Group IB). On initial examination there was no difference in volumes and EF between these 2 groups. On follow-up, Group IA patients remained in New York Heart Association class I or II. The LV end-diastolic volume increased in the Group IA patients from 164 ± 27 to 203 ± 54 ml (p <0.01); LV ejection fraction tended to increase (from 51 ± 5 to 56 ± 8, p <0.06). On follow-up, Group IB patients had larger LA and LV volumes than Group IA patients. Fourteen patients were initially treated surgically (Group II). All but 1 were in New York Heart Association Class III or IV. On Initial examination LVEF was lower than in Group IA patients (51 ± 5 versus 43 ± 7, p = 0.05), but there was no difference in LV or LA volumes. On follow-up, a mean of 19 months after surgery, LVEF and LA volumes decreased. We conclude that a subset of patients with a flail mitral leaflet may be followed clinically without deterioration in LV function. Initial LVEF and hemodynamics are reasonably normal. Because increasing LV and LA volumes and changing clinical status are not a function of time, frequent 2-D echo and clinical evaluations are warranted in these patients. After mitral valve replacement, LVEF decreases without a significant change in LV volume.