Echocardiographic features of truncal abnormalities. Special emphasis to the evaluation of pulmonary arteries.

9 patients with persistent truncus arteriosus, 11 patients with pseudotruncus and 2 patients with hemitruncus, ranging in age from 6 months to 29 years, have been studied by M-mode and two-dimensional echocardiography (2-D echo). In all patients the diagnosis was confirmed by cardiac catheterization and angiocardiography; in 10 of them surgical or autopsy documentation was available. Peripheral contrast echocardiography was performed in 13 patients. A variable degree of truncal or aortic override was observed in 7 of 9 patients with truncus arteriosus and in all patients with pseudotruncus by M-mode or two-dimensional echocardiography. By 2-D echo the truncal origin of the right and left pulmonary arteries was visualized in 7 of 9 of the patients with truncus arteriosus. Visualization of one aberrant pulmonary artery from the aortic wall was assessed retrospectively in 2 patients with hemitruncus. A pulmonary atretic valve region was recorded in 10 of 11 of the patients with pseudotruncus. Peripheral contrast echocardiography enabled to distinguish patients with complete obstruction to pulmonary flow from patients with unobstructed right ventricular outflow tract. By showing no direct connection between the pulmonary arteries and the ascending aorta or direct continuity between one or both pulmonary arteries and truncal or aortic root, differentiation of pseudotruncus arteriosus from truncus or hemitruncus may be achieved by 2-D echo.