Prevalence of fetal left ventricular hyperechogenic foci in a low risk population.

Objective: To ascertain the prevalence and clinical significance of small hyperechogenic foci detected in the fetal left ventricle in routine ultrasound screening of pregnant women attending our hospital.

Population And Methods: From April 1994 to April 1995, 1135 consecutive pregnant women examined at the obstetric ultrasound unit of our hospital were studied prospectively. A postnatal cardiologic examination was performed when signs of cardiopathy were observed at the prenatal ultrasound investigation or the neonatal examination.

Results: Congenital heart disease was detected in 10/1148 infants born (0.9%); eight diagnoses were made prenatally (detection rate 80%). The prevalence of left ventricular hyperechogenic foci was 3.2% (37/1148 fetuses). In 35 cases (94.6%) the foci were no longer observed at the routine third trimester examination. Only in two cases (5.4%) did foci persist at the postnatal examination but without clinical signs of cardiopathy or karyotype anomalies. No association was observed between foci and major structural abnormalities. The foci were single in 32 cases (86.5%). Four foci (10.8%) were located at the interventricular septum, five (13.5%) bilaterally at the papillary apparatus of the mitral valve, and the others at the ventricular wall. No focus was associated with incompetence of the affected valve, whereas five (13.5%) were associated with a fetal disorder.

Conclusions: The prevalence of intracardiac hyperechogenic foci in our general population considered at low risk was more than five times greater than that reported in the literature. Foci were not associated with structural heart defects or chromosomal abnormalities. Persistence during the third trimester and postnatal life was rare and without evident signs of heart disease.