Early sonographic diagnosis of fetal small left heart ventricle with a normal proximal outlet tract: a medical dilemma.

A small left heart ventricle with a normal outflow tract was detected by transvaginal ultrasound in 16 fetuses at 14-16 weeks' gestation. A high incidence of associated anomalies was found in these fetuses, namely coarctation of the aorta (5), abnormal karyotype (4), cystic hygroma (4), and ventricular septal defect (3). The incidence of extracardiac anomalies was probably even higher, since post-mortem and karyotype examinations were not performed in all cases of termination of pregnancy. In patients who decided to continue the pregnancy (7), a normal left ventricle was observed in four cases on follow-up scans. Three of these neonates were normal after delivery and one had several cardiovascular anomalies. Out of three fetuses with asymmetric ventricles on follow-up scan, one infant had a normal outcome. The high incidence of associated fetal anomalies in cases of a small left ventricle raises a medical dilemma in counselling the parents.