Fetal cardiac axis in tetralogy of Fallot: associations with prenatal findings, genetic anomalies and postnatal outcome

ABSTRACT Objective To compare prenatal findings, associated genetic anomalies and postnatal outcome in fetuses with tetralogy of Fallot (TOF) with normal cardiac axis (CAx) and those with abnormal CAx. Methods In this retrospective cohort study, 85 cases diagnosed with TOF by prenatal ultrasound at our clinic between 2005 and 2015 were reviewed. Follow‐up ultrasound and postnatal outcome were available for 68 cases. One case complicated with absent pulmonary valve syndrome and a further seven cases diagnosed postnatally with anomalies other than TOF were excluded from the study. The remaining 60 cases of postnatally confirmed TOF were divided according to CAx into two groups: those with normal CAx (n = 33) and those with abnormal CAx (n = 27). CAx was defined as the angle between the interventricular septum and midline of the fetal thorax at the level of the four‐chamber view. CAx > 65° or