Atrial myxoma, a continuing diagnostic challenge

Despite increased awareness of atrial myxoma, the lesion remains a diagnostic challenge, largelydue to a highly variable clinical picture. Some unusual manifestations of atrial myxoma are illustrated by 6 cases. The relatively slow growth of left atrial myxoma was demonstrated in a 15 year old boy thought to have mitral insufficiency from birth and by a 10 year period of observation in a 63 year old woman. The woman also had co-existent mitral stenosis. Coexistent congenital heart disease was found in a 73 year old man thought to have severe lung disease with arterial unsaturation. Cardiac catheterization showed a right to left shunt through an atrial septal defect due to a right atrial myxoma obstructing the tricuspid valve. Angiocardiography demonstrated the above lesions, as well as left atrial myxomas in 2 patients with clinical findings of mitral valve disease. A fatal complication occurred during transseptal catheterization in a woman believed clinically to have mitral stenosis. Occlusion of the mitral valve by a left atrial myxoma occurred when the catheter entered the left atrium above the tumor. The importance of angiography in the diagnosis of atrial myxoma is stressed, and the avoidance of transseptal catheterization in suspected cases is emphasized.