Figure-of-eight circulation in thoracopagus conjoined twins with a shared heart

A pair of thoracopagus conjoined twins is described in whom a common heart with atrial and ventricular conjunction was demonstrated by cardiac catheterization and at autopsy. Each twin had an independent noncommunicating single ventricle with separate origins of the aorta and pulmonary arteries. A complex pattern of pulmonary and systemic venous return resulted in a fugure-of-eight circulation not previously described which precluded surgical intervention. This report demonstrates the feasibility of detailed hemodynamic assessment in thoracopagus twins and the value of selective ventricular angiography with careful observation of the venous phase in determining an accurate preoperative diagnosis.