Objective: To evaluate the importance of fetal heart axis assessment and the efficacy of prenatal US screening for conotruncal anomalies.
Methods: Evaluation of fetal heart axis in pts diagnosed in the reference perinatal cardiology center between 2005-2008. Out of 531 fetuses with CHD data of 83(15,6%) with conotruncal anomalies (TOF,DORV,CAT,TGA) was reviewed.
Results: Most pts were referred due to suspicion of CHD by obstetricians who were trained in screening program. Mean maternal age was 29 and mean gestational age at the time of diagnosis(GA) was 27. 58(70%) patients were in a low risk group. There were TOF-42, DORV-24, TGA-13 and CAT-4. Karyotyping was performed in 53(64%) fetuses, abnormal-15(18%). The fetal heart axis was assessed in 80(96%) cases. Among TOF fetuses mean GA was 25, the mean heart axis was 63º. 17(40%) were from high risk group. Among DORV fetuses mean GA was 30, the mean heart axis was 60º. Only 5(21%) pts were from high risk group. All CAT pts were from the low risk group. The mean GA was 29 and the mean fetal heart axis was 88º. In TGA pts mean GA was 27, the mean heart axis was 46º. 3(23%) pts were from the high risk group.
Conclusions: Fetal heart axis is helpful in diagnosis of CAT,TOF and DORV, but in fetuses with TGA it was close to normal. Detection of TGA in screening US exam is still difficult due to normal fetal heart axis and 4-ch view, so assessment of outflow tracts should be recommended.