Quantitative Study Of Normal Fetal Cardiac Atrial-to-ventricular Length Ratio

Objective Atrioventricular septal defects(AVSDs) are the most common cardiac abnormality in fetus with numerical chromosomal aberrations ,in particular trisomy 21.we intend to esteblish a new ultrasonography index―cardiac atrial-to-ventricular length(AVL) ratio , define its value and estimate the influence of gestational age on it,we tnink it may substantially improve antenatal detection of AVSDs and accordingly improve the ability to diagnose trisomy 21 antenatally.Methhods Fetal ultrasonography were performed on 133 normal fetus (16~40W). cardiac AVL ratio was obtained by measuring the heart length and ventricular length. Correlation analysis was performed in order to check AVL ratio for dependence from gestational ages.Results In normal fetuses, AVL ratio was 0.48±0.08(normal reference range 0.32 to 0.64)and found to be independent of gestational age.Conclusions The AVL ratio is a simple,noninvasive and reliable index to discriminate hearts with AVSD and normal cardiac anatomy.It has important potential role in diagnosing AVSD, accordingly ,may improve the ability to diagnose trisomy 21 antenatally and was expected to be incorporate into chromosomal marks.