The coronary sinus in the fetus

Introduction The normal coronary sinus drains venous blood from the cardiac veins to the right atrium. lit some instances, the coronary sinus may be d ilated due to volume or more rarely pressure overload. Aims To assess the feasibility of detecting the coronary sinus in the fetus and to establish the normal values of the coronary sinus dimensions throug hout gestation. Subjects and methods Fetal echocardiography was performed in 78 normal fetu ses from the 16th to the 40th week of gestation (median 25 week). The coron ary sinus was measured in four-chamber view (87% of cases) or in parasterna l short axis view equivalent (13%). A second group of I nine fetuses with a dilated coronary sinus was compared to the normal group. Results Adequate imaging of coronary sinus tons obtained in 97.4% of the no rmal fetuses. The diameter of the coronary sinus I ranged from I to 3.2 mm (2 mm +/- 0.13 mm, mean +/- 5% confidence interval) and correlated well wit h the age of Pregnancy (r = 0.86). The length-to-diameter ratio of 24% (+/- 6%) did not vary throughout pregnancy All nine fetuses with a dilated coro nary sinus had a persistent left superior vena cava which drained into it. The diameter of the coronary sinus teas approximately, three times larger i n the abnormal group with a diameter-to-length ratio of approximately 83% ( P < 0.0001). Conclusion The coronary sinus is readily identified In the fetus. tt gradua lly increases during pregnancy. An abnormal coronary sinus is easily diagno sed and should prompt the sonographer to look for a persistent left superio r vena cava.