Echocardiographic assessment of conjoined twins with congenital heart disease in Shanghai.

Background: The aim of this study is to improve the diagnosis of congenital heart disease in conjoined twins using echocardiography.

Methods: Six sets of conjoined twins at Shanghai Children's Medical Center and Xin-Hua Hospital from 1980 to 2006 were assessed retrospectively. Cardiac anomalies of varying degrees of severity were first evaluated using 2D echocardiography. Tissue Doppler imaging (TDI) was then performed if fused ventricles were suspected. Peak systolic velocities, peak systolic strain rates, and peak systolic strains at the fused myocardium were quantitatively measured using strain rate imaging (SRI). If the M-mode echocardiographic image was poor or difficult to measure, the myocardial performance index (MPI) of the left ventricle was calculated.

Results: Intracardiac anomalies were diagnosed correctly using echocardiography and confirmed by surgical findings. Cardiac functional assessment using MPI demonstrated heart failure in three out of the eight individuals. Subtle conjunction of the ventricles, however, were more difficult to visualize and two sets of conjoined twins with fused hearts could not be clearly demonstrated by echocardiography. In one case of suspected ventricular wall conjunction, TDI showed separate ventricular myocardia which was confirmed at surgery.

Conclusions: Intracardiac anomalies and ventricular function can be readily demonstrated by echocardiography, but subtle conjunction of the ventricles may be more difficult to visualize. TDI may be required if there is uncertainty about the degree of cardiac fusion.