Double-outlet of Right Ventricle of Recipient Fetus in Severe Mid-trimester Twin–Twin Transfusion Syndrome

A 37 years old Thai pregnant woman with MCDA twins, para 1, was suspected of severe twin-twin transfusion syndrome (TTTS) at 21 weeks’ of gestation. Quintero staging was applied in this cases. Neither of the fetuses exhibited signs of hydrops. Abnormal four-chamber view was demonstrated in a recipient fetus. Two-dimensional and color Doppler showed complex cardiac malformations which include (1) hypoplastic left ventricle, and (2) large atrial septal defect, (3) atretic tricuspid valve, and (4) the blind right atrium communicating with the left atrium through the ostiumprimum defect. For more information, threedimensional (3D) echocardiography was used toreconstruct“thin slab” of the fetal heart and its outflow tracts. A double-outletright ventricle (DORV) was highly suspicious. Congenital cardiac anomaly can decompensate the compromised myocardium of the recipient fetus. In addition to conventional 2D echocardiography, the application of advanced 3D echocardiography with ‘thin slab’ technique can help for the examination of fetal heart.