Congenital mitral insufficiency.

T HE INFREQUENT REPORTS of mitral insufficiency on a congenital basis rcflect the apparent rarity of this condition. Aneurysmal dilatation of the left atrium in a 5year-old girl with clinical findings suggesting mitral insufficiency has been described by Semans and Taussig in 1938.1 Postmortem examination of this patient revealed thickening of the mitral and tricuspid valves, saccular dilatation of the left atrium, and cardiac hypertrophy. The chordae tendineae also were noted to be greatly shortened. Prior2 has described two adults with congenital malformations of the mitral valve. In one, duplication of the mitral orifice was present while in the other the posterior leaflet lacked the proper chordal attachment. Kjellberg and co-workers3 described the clinical and hemodynamic findings in three patients with congenital mitral incompetence. In two of these patients the left atrium was aneurysmally dilated and the appendage was prominent. In the third patient the malformation was present in association with corrected transposition of the great vessels. One of these patients died, and at postmortem examination the anterior cusp of the mitral valve was found to be lacking and the posterior cusp was rigid. Helmholz et al.4 have described mitral insufficiency in association with corrected transposition of the great vessels. This has also been discussed by Anderson and associates5 in their review of corrected transposition. Linde and Adams6 reported mitral insufficiency in association with a patent ductus arteriosus in three pa-