Critical pulmonary stenosis with intact ventricular septum and fetal arrhythmias.

A 23-year-old woman, gravida 1, was referred to our hospital for possible fetal distress at 32 weeks of pregnancy. A fetal cardiotochogram showed a reactive pattern, but mild continuous bradycardia and an intermittent pulse were observed, regarded as a sinus type and a type of A-V block, respectively. The continuous deceleration of the heart rate to 95 bpm was observed frequently at 35 weeks, 3 days of gestation. Thus, an emergent cesarean section was performed and a viable 2,082 g female infant was delivered. The neonate gradually became cyanotic, and an echocardiogram was performed. The neonate was regarded as a right ventricular outflow obstruction with intact ventricular septum. Unlike other cases, the infant revealed a moderately developed right ventricle despite a severely stenotic tricuspid valve. The infant died 27 days after birth and an autopsy established the diagnosis of critical pulmonary stenosis with intact ventricular septum. Right ventricular myocardial sinusoidal-coronary artery connections, one of the major features of this type of heart anomaly, was speculated to be involved in the cause of fetal bradyarrhythmias.