To determine the echocardiographic features of congenital mitral valve stenosis (MS), echocardiograms were performed on 24 children with this defect. The pattern of mitral valve (MV) motion, the excursion of the anterior leaflet and the rate of early diastolic closure (E-F slope) were determined and compared to similar data from 145 normal children.
Diastolic vibration of both MV leaflets was present in 15 of 24 patients with MS. In 9, the posterior leaflet moved anteriorly in early diastole, parallel to the anterior leaflet. Four patients had diastolic anterior motion of the posterior leaflet in the absence of vibration. In normal patients with a heart rate less than 120 beats/min there was MV reopening (“A” wave) following atrial contraction. The “A” wave was absent in 14 of 18 patients with MS in whom the heart rate less than 120 beats/min.
Patients with severe MS tended to have a greater decrease in E-F slope and more frequently exhibited anterior diastolic movement of the posterior MV leaflet and absence of the “A” wave than patients with mild or moderate MS.
The reduced E-F slope and abnormal motion of the posterior MV leaflet are similar to the echocardiographic appearance of acquired MS. However, diastolic vibration of the MV leaflets appears to be unique to the congenital forms of MS.