Surgical treatment of endocardial cushion defects.

A recent surgical experience with the spectrum of atrioventricular (A-V) canal is reviewed. Twenty-five patients underwent surgery for the partial and complete from of this defect in the 4 years from 1971 through 1974. Sixteen had a partial defect, two a transitional defect and seven complete A-V canal. The characteristic murmurs accompanied by cardiac enlargement, pulmonay overcirculation and left axis deviation in the electrocardiogram were sufficient for diagnosis in most cases. Cardiac catherization was performed in all patients preoperatively and in 11 postoperatively. The operative approach, including a double patch modification of the usual repair for complete canal, is considered. Definitive repair, rather than pulmonary arterial banding, is advocated regardless of the patient's age. The operative mortality rate is low in patients with the ostium primum type of defect but is related to associated intracardiac anomalies in those with the complete form of the defect. Residual mitral insufficiency is a common finding after surgical repair of both partial (75 percent) and complete (100 percent) A-V canal. Although no patient in the series died of florid mitral regurgitation, the long-range effects of this complication may lead to mitral valve replacement.