[Anomalies in the development of the sinus venosus as a probable cause of heart rhythm disorders and fetal hydrops].

Prenatal ultrasonic examination during the 28th week of gestation revealed a transient disorder of the cardiac rhythm in the foetus. Subsequently repeated echocardiographic examinations confirmed foetal hydrops which together with signs of EP gestosis of the mother was an indication to terminate pregnancy during the 29th week by Caesarean section. In the severely hydropic male foetus in the enlarged anterior wall of the right atrium an atypical vascular canal was found which was in the close vicinity of the sinoatrial node. The latter most probably caused intermittent intrauterine supraventricular tachycardia in a heart with a normal configuration in other respects.