Variability of echocardiographic discontinuity in double outlet right ventricle and truncus arteriosus.

The widespread application of echocardiography to the field of congenital heart disease has led to the development of a concept of "echocardiographic discontinuity" for the diagnosis of some conditions. Although this is a valuable sign in differentiating such entities as tetralogy of Fallot, truncus arteriosus and double outlet right ventricle, the reported cases illustrate that the echocardiographic recognition of discontinuity may be complicated by technical factors. In addition, the differential diagnosis must include truncus arteriosus with coexistence of anterior and posterior discontinuity.