Cardiovascular anomalies in thoracopagus twins and the importance of preoperative cardiac evaluation.

Four pairs of thoracopagus twins have been described. Cardiac catheterisation was performed in all the cases. Angiocardiographic and necropsy findings suggest that the most common abnormality was some form of univentricular heart. The communication between the 2 hearts was at atrial level in 2 cases. Separation was performed in 1 of these cases but only 1 of the twins survived for 14 hours after operation. It is suggested that full cardiac catheterisation with selective angiocardiogram is essential before separation is considered. Identical heart rates were observed in each pair and there was invariably a major communication between the hearts of the twins.