Persistent truncus arteriosus: A study of 66 autopsy cases with special reference to definition and morphogenesis

Sixty-six hearts were examined in which a single arterial trunk, leaving the base of the heart through a single semilunar valve, supplied the aorta, pulmonary artery and coronary arteries. Careful attention was paid to the infundibular morphologic features in these hearts, and these were compared with findings in 24 hearts with single aortic trunk, pulmonary atresia and ventricular septal defect. It was concluded that the two anomalies represented morphologically discrete conditions. This was particularly true with regard to the disposition of the infundibular septum, the ventriculo-infundibular fold and the relation of the coronary arteries to the semilunar sinuses. Although it is theoretically possible for a heart with true persistent truncus arteriosus to have absence of the pulmonary trunk and right and left pulmonary arteries, it is argued that such hearts (“truncus type IV”) are best classified as pulmonary atresia with ventricular septal defect. It is also argued that hearts with a common arterial trunk supplied through discrete ventricular outflow tracts and two semilunar valves are best considered examples of aorticopulmonary window. It is suggested that persistent truncus arteriosus is best defined as that condition in which a single arterial trunk leaves the heart through a single semilunar valve and supplies the aorta, one or both pulmonary arteries and the coronary arteries.