Cardiac Axis Deviation in Anomaly Scan: A Marker for Underlying Cardiac Anomalies

Area of Science:

• Prenatal diagnostics
• Fetal cardiology
• Medical imaging analysis

Background:

• Congenital heart defects (CHD) are a major cause of perinatal mortality.
• Cardiac axis assessment during anomaly scans is a proposed method for detecting cardiac anomalies.

Purpose of the Study:

• To evaluate the association between cardiac axis deviation and congenital cardiac defects.
• To assess the diagnostic performance of cardiac axis as a screening parameter for CHD.

Main Methods:

• Prospective observational study of 810 pregnant women (18-24 weeks gestation).
• Cardiac axis measured on the four-chamber view; classified as normal (25°-65°), left (>65°), or right (<25°).
• Analysis of associations using Chi-square test; diagnostic performance calculated.

Main Results:

• Cardiac anomalies detected in 6.3% of fetuses; significantly higher in those with axis deviation (67.4% large, 83.3% small) vs. normal axis (0.7%).
• Cardiac axis deviation demonstrated high sensitivity (90.2%) and specificity (97.6%).
• Significant associations found with extracardiac anomalies; adverse outcomes more common with CHD.

Conclusions:

• Cardiac axis deviation is a robust marker for congenital cardiac anomalies.
• A normal cardiac axis has a high rule-out value for CHD.
• Routine cardiac axis assessment can improve early risk stratification and referral for fetal anomalies.