Publication:

Predictivity of right ventricular outflow tract velocity-time integral in detection of the size of secundum atrial septal defect in children

Background Atrial septal defect (ASD) is a common congenital heart defect in children, with secundum ASD being the most frequent type. Unrepaired defects can cause right ventricular overload and pulmonary hypertension. While Qp:Qs ratio requires four parameters to detect shunts, the right ventricular outflow tract velocity-time integral (RVOT VTI) alone can indicate significant interatrial shunts and predict ASD size. This study aimed to evaluate RVOT VTI in predicting secundum ASD size in children.

Methods This cross-sectional study was conducted in department of pediatric cardiology, Bangladesh Medical University, Dhaka, from July 2023 to June 2024. A total of 30 patients were selected as study subjects by a purposive sampling technique. The data were coded, entered, and analyzed using Statistical Package for the Social Sciences (SPSS) version 25.0.

Results The results of this study indicate that the majority of children (60%) had an RVOT VTI >20 cm, and most secundum ASDs were moderate in size as measured by both TTE and TEE. A positive, though statistically non-significant, correlation was observed between RVOT VTI and ASD size measured by both TTE (r=0.271, p<0.147) and TEE (r=0.303, p<0.104). ROC analysis identified RVOT VTI cut-off values of 19 cm and 15 cm for differentiating large and moderate-to-large ASDs, with corresponding accuracies of 60% and 93.3%, respectively. The 15 cm cut-off demonstrated higher diagnostic performance, showing 96% sensitivity and 75% specificity.

Conclusions This study highlighted the potential role of RVOT VTI as a useful, non-invasive parameter for estimating the size of secundum ASDs in pediatric patients. It demonstrated that RVOT VTI can help distinguish between small, moderate, and large defects. At a cut-off value of 19 cm, RVOT VTI showed an accuracy of 60% in differentiating large ASDs from small to moderate ones.