Coronary arterial origin in persistent truncus arteriosus.

Specimens of heart from 30 subjects with persistent truncus arteriosus were studied for the nature and sites of coronary arterial origin. These factors were related to the sinuses of the truncus valve. Bicuspid truncal valve was observed in six cases (20%) and tricuspid in 21 cases (70%). Single coronary artery was observed in four cases (three with tricuspid and one with quadricuspid truncal valves). In three other cases the coronary arteries arose separately but near one another. There was a strong tendency for the left coronary artery to arise from a more posterior level than it does normally from the aorta. It was common for the posterior descending artery to arise from the left circumflex artery. This arrangement was noted in eight of 25 cases (32%) with single posterior descending coronary artery. In five other cases, two posterior descending arteries were present, one arising from the left circumflex and the other from the right coronary artery.