1 Departments of Paediatrics, Pathology and Anatomy, University of Toronto, and the Research Institute of the Hospital for Sick Children, Toronto
Eleven cases of congenital mitral atresia with normal aortic valve are presented, and these plus 41 other cases from the literature are summarized.
The average survival was 6 months. Cyanosis, dyspnea, and failure to gain were the common symptoms. Auscultation was of limited value. Congestive heart failure was frequent. The roentgenographic findings varied, but the heart usually appeared large. Right ventricular hypertrophy with a qR pattern in the right precordial leads was the chief electrocardiographic finding. Angiocardiograms showed a large right atrium and ventricle, and simultaneous filling of both great vessels, and also demonstrate pulmonary stenosis and transposition of the great vessels, if present. Cardiac catheterization showed a rise in blood oxygen saturation in the right atrium, and systemic levels of systolic pressure in the right ventricle.
At necropsy, there was no mitral valve. The left atrium was small, and usually communicated with the larger right atrium by an atrial defect. Anomalies of the venous return were common. The right ventricle was large, and the left ventricle was small, rudimentary or absent. Pulmonary stenosis or atresia, and transposition of the great vessels were frequently associated. The ductus arteriosus was usually patent, and preductal coarctation was common. Nearly half the cases had associated major extracardiac defects, especially asplenia. The microscopic appearance of the pulmonary arteries was abnormal in some older cases.
The embryology and the differential diagnosis of this malformation are discussed. There is no specific treatment.
Submitted on May 18, 1959