Imperforate tricuspid valve with dysplasia of the right ventricular myocardium, pulmonary valve, and coronary artery: a clinicopathological study of nine cases.

Nine cases of imperforate tricuspid valve associated with dysplasia of the right ventricular myocardium, pulmonary valve, and right coronary artery are described. The mean frontal QRS axis of the electrocardiograms did not indicate left axis deviation in seven of the nine. Two-dimensional echocardiograms showed an imperforate tricuspid valve, normally aligned atrioventricular septum, and an irregular-shaped right ventricular cavity with a thin wall. In three cases with absence of the pulmonary valve, pulsed Doppler echocardiograms of the right ventricular outflow tract revealed antegrade flow during systole and retrograde flow during diastole, and selective angiography through a persistent ductus arteriosus showed retrograde filling of the blind-ended right ventricular cavity via the main pulmonary artery. Necropsy examinations showed an imperforate tricuspid valve with a thin-walled aneurysmal right ventricle in all six cases examined. Pulmonary atresia was observed in two cases, and the absence of the pulmonary valve in four. The right coronary artery was hypoplastic in four cases and absent in two. A shunt operation should be carried out in early infancy to prevent hypoxia after closure of the ductus arteriosus.