Double mitral valve orifice in atrioventricular defects

SUMMARY Eleven patients with double mitral valve orifice and atrioventricular defects were studied, and the diagnosis proven by open heart surgery. The correct preoperative diagnosis was suggested by a characteristic angiographic appearance of the medial border of the left ventricle. M-mode echocardiography may show the two orifices which are better seen on two dimensional echocardi-ography. Two operative deaths occurred in patients with a slightly obstructive valve, and one late death followed mitral valve replacement. Eight patients did well after minor repair to a cleft, or leaving the valve untouched. Occasionally a double mitral orifice, if disorganised and slightly stenotic, may cause early deterioration in a patient with an otherwise uncomplicated ostium primum defect. The surgeon should be forewarned of this mitral anomaly since simple repair may be difficult. The mitral valve in all forms of atrioventricular defects is pathologically abnormal, with a characteris-tic cleft in the anterior cusp which may be partial or complete. In 3 to 5 % of cases, however, a double orifice mitral valve is found. ' This valve structur