Ultrasonographic left cardiac axis deviation: a marker for fetal anomalies.

Abstract

To determine if a relation exists between left cardiac axis deviation and fetal anomalies. Estimation of cardiac axis was attempted prospectively as part of the cardiac examination in approximately 41,500 second- and third-trimester fetuses scanned between 1987-1993. Those with heart axes greater than 75 degrees to the left were considered to have left axis deviation. Only cases with postnatal follow-up were included. Thirty-four fetuses with left cardiac axis deviation had postnatal follow-up; eight were normal and 26 abnormal (positive predictive value 76%). Twenty-one fetuses had cardiac abnormalities (ten of these had additional extracardiac findings), and five had extracardiac findings only. Although left cardiac axis deviation can occur as an isolated sonographic finding in an otherwise normal fetus, most cases will demonstrate abnormalities of cardiac and/or extracardiac anatomy. Left cardiac axis deviation is largely associated with cardiac abnormalities, especially conotruncal anomalies, which may not be detectable by a four-chamber view alone. Therefore, the cardiac axis should be examined routinely as part of the four-chamber view of the fetal heart.