Organic and functional pulmonary atresia with intact ventricular septum

Abstract

1. 1. Pulmonary atresia with intact ventricular septum is a rare anomaly and is usually fatal within the first few weeks of life. 2. 2. The fundamental defect is complete obstruction of the pulmonary valve, the circulation being maintained by blood flow from right atrium to left atrium. The left ventricle functions as a single ventricle; a mixed venous and arterial blood is ejected from the ventricle into the aorta. Life depends on the size of the patent ductus from which the total pulmonary circulation is derived. 3. 3. The competence of the tricuspid valve determines the size of the right ventricle. When the valves are competent the right ventricular chamber is small and the walls hypertrophied. When the valves are incompetent the right ventricle is dilated and hypertrophied. 4. 4. Three cases of pulmonary atresia with intact ventricular septum and tricuspid incompetence are described. Cyanosis and dyspnea were associated with considerable cardiomegaly, a triple rhythm and a loud pansystolic murmur maximal at the lower sternal edge radiating to the lower right side of the chest. The electrocardiogram showed severe right atrial hypertrophy and right ventricular hypertrophy with a qR complex in V 1. Radiologically, the heart was grossly enlarged with aneurysmal dilatation of the right atrium, right ventricular enlargement and marked pulmonary oligemia. 5. 5. One case of functional pulmonary atresia with intact ventricular septum is described, due to a combination of Ebstein's anomaly of the tricuspid valve and a very large patent ductus arteriosus. The clinical picture was identical with organic pulmonary atresia except for the electrocardiogram, which showed a QRS pattern in V 1 with slurring of the terminal S in the left precordial leads. An angiocardiographic study from the right atrium showed late filling of the pulmonary arteries from the aorta after passage of opaque medium from the aneurysmal right atrium to the left atrium and left ventricle.