Congenital mitral atresia.

Mitral atresia is a rare congenital anomaly, but its true incidence is difficult to assess. In 1962, Fontana and Edwards reported 8 cases of isolated mitral atresia and found 24 others in published reports. They also described 5 cases of combined mitral and aortic atresia and found 23 other published cases. From Britain, MacMahon, McKeown, and Record (1953), in a careful survey of congenital heart disease in children bom in a three-year period in Birmingham, did not mention this anomaly, and Coleman (1965) did not encounter a single case in his study of serious congenital heart disease in infants. Mitral atresia is, however, often associated with other congenital cardiac malformations, and cases are often classified in other groups. Lev (1952) and Noonan and Nadas (1958) considered mitral atresia as part of the hypoplastic left heart syndrome, and Muir (1960), who had seen 5 cases in 19,415 necropsies in Singapore, grouped mitral atresia with cases of cor triloculare because they function similarly. The recent coincidence of finding hearts with mitral atresia in necropsies on two consecutive days prompted a review of the other hearts with this anomaly examined in this hospital. The poor prognosis of infants with this anomaly is reflected in the relative frequency of mitral atresia at necropsy in the newborn period. An analysis of deaths from congenital heart disease in the newborn period at Johns Hopkins University showed mitral or aortic atresia or both to be the foiuth most frequent group of anomalies (Mehrizi, Hirsch, and Taussig, 1964). Of these infants, 65 per cent died between the third and seventh day of life. In Toronto, 4 per cent of neonatal deaths from congenital heart disease were due to mitral atresia or stenosis (Rowe and