Differential Effect of the Ratio of Right Ventricular Volume to Left Ventricular Volume in Children with Repaired Tetralogy of Fallot.

We aimed to compare the diagnostic value of indexed right ventricular end-diastolic volume (RVEDVi) and the ratio of right ventricle volume to left ventricle volume (RV/LV ratio) in prediction of the severity of pulmonary regurgitation (PR) expressed as the PR fraction (PRF) after surgery of tetralogy of Fallot (TOF). Forty-one patients with repaired TOF were included in the study. RVEDVi, LVEDVi, RV/LV ratio, PRF and ejection fraction were measured with magnetic resonance imaging. A PRF of more than 20% was considered significant. The predictive capability of two markers (RVEDVi and RV/LV ratio) for significant PR was compared using multivariate linear regression analysis and receiver operating characteristic (ROC) analysis. Both the RV/LV ratio and RVEDVi showed a correlation with PRF (r = 0.526/0.321, p = 0.001/0.041) in the correlation analysis, but in multivariate regression analysis the only independent predictor of PRF was the RV/LV ratio (F = 14.890, p = 0.001). ROC analysis revealed that a better discrimination of significant PR (>20%) from slight types (=20%) PR can be reached with the RV/LV ratio than RVEDVi (AUC = 0.805/0.709, p = 0.01). The RV/LV ratio was better than RVEDVi at differentiating mild from moderate PR (p = 0.006 vs. p = 0.153), and proved superior over RVEDVi in predicting PR based on the PRF criterion.