Atypical Fallot's tetralogy with doubly committed subarterial ventricular septal defect. Diagnostic value of...

Five patients with clinical features of tetralogy of Fallot had subarterial doubly committed ventricular septal defect (VSD) with absence or deficiency of the infundibular septum. Two-dimensional (2-D) echocardiography differentiated this special group from those with the usual Fallot's anatomy. In addition to the long-axis view of the left ventricle which showed the subaortic VSD and the aortic and mitral fibrous continuity, the short-axis view at the cardiac base clearly demonstrated the subpulmonary extension of the VSD in the atypical group. Two-dimensional echocardiography was found superior to biplane angiography, which in 3 patients suggested the erroneous diagnosis of double-outlet right ventricle with pulmonic valve stenosis. This variant form of Fallot's tetralogy poses special surgical problems.