Left ventricular outflow tract obstruction in transposition of the great arteries: an angiographic study of 74 cases.

Recent advances in techniques of angiocardiography now allow highly accurate assessment of the anatomy of the left ventricle in patients with transposition of the great arteries. The cineangiograms of 225 children with transposition were reviewed using axial cineangiographic techniques and 33 percent were found to have significant left ventricular outflow tract obstruction with or without coexisting ventricular septal defects. The varieties of left ventricular outflow tract obstruction and the associated ventricular septal defects found in this group of patients are described, illustrated and correlated. The advantages of axial angiocardiography in the diagnosis of transposition are pointed out, and the techniques used to produce the axial angiocardiograms are reviewed.