Intrauterine hemodynamics of tricuspid valve dysplasia in a growth-restricted infant.

We present a case of fetal tricuspid valve dysplasia, which was diagnosed at 22 weeks of gestation during a routine obstetrical examination. Serial fetal echocardiographic evaluation revealed progressive right ventricular outflow tract obstruction and persistent cardiomegaly. A female infant weighing 1,916 g was delivered by elective cesarean section at 38 weeks of gestation. Longstanding compression of the fetal lungs secondary to the persistent cardiomegaly resulted in severe respiratory distress and cyanosis immediately after birth. Although, mechanical ventilation and continuous infusion of prostaglandin were instituted, the infant died of respiratory failure at 21 days of age. During the pregnancy, the fetus exhibited intrauterine growth restriction, but hydrops did not occur. In regard to the fetal hemodynamics in this cardiac anomaly, transatrial communication is essential for fetal survival. The diameter of the fossa ovalis, which is a marker of transtrial blood flow, was adequate in this case. However, marked enlargement of the right heart associated with regurgitation interfered with left ventricular filling and output, which resulted in restriction of the combined ventricular output and intrauterine fetal growth restriction.