Isolated anterior mitral cleft. Two dimensional echocardiographic assessment and differentiation from "clefts" associated with atrioventricular septal defect.

Five patients with isolated clefts in the anterior leaflet of the mitral valve, unassociated with atrioventricular septal defects, are described. All had significant mitral regurgitation, with the cleft being the only abnormality in three. Two patients had an associated ventricular septal defect, one with a straddling right atrioventricular valve. Angiocardiography in four showed moderate regurgitation, but was not able to delineate the aetiology. Two dimensional echocardiography showed a constant defect in the anterior leaflet, pointing towards the left ventricular outflow tract. This differed from 30 cases with atrioventricular septal defects where the "cleft" pointed towards the interventricular septum and was situated between the anterior and posterior bridging leaflets. All cases with isolated clefts had surgical correction, with minimal residual regurgitation on follow-up examination in two cases. Our current policy in patients with uncomplicated isolated cleft involves non-invasive assessment of these children and surgical correction if the regurgitation is significant.