Determinants of left- and right‑ventricular ejection fractions in patients with repaired tetralogy of Fallot: a cardiac magnetic resonance imaging study

INTRODUCTION There are inconsistent data regarding the factors affecting left ventricular ejection fraction (LVEF) and right ventricular ejection fraction (RVEF) in patients after tetralogy of Fallot (TOF) repair.
OBJECTIVES The aim of the study was to assess the determinants of LVEF and RVEF in a large cohort of patients with repaired TOF.
PATIENTS AND METHODS The study comprised 122 patients with repaired TOF (median age, 24.2 years; interquartile range, 20.3–30.9; men, 60.6%) who had undergone cardiac magnetic resonance imaging study. Predictors of LVEF, RVEF, and RVEF corrected for shunting or regurgitations (cRVEF) were identified with the use of linear regression analyses. 
RESULTS There was a weak correlation between RVEF and LVEF (r = 0.39, P <0.0001). A multiple regression analysis revealed the following independent predictors of LVEF: positive predictor – RVEF (P = 0.0002); negative predictors – pulmonary regurgitation fraction (PRF, P = 0.01) and male sex (P = 0.001). RVEF was predicted independently by positive predictors such as LVEF (P <0.0001) and LV end‑diastolic volume (LVEDV, P = 0.04) and negative predictors such as right ventricular mass (P <0.0001) and number of previous cardiothoracic surgery interventions (P = 0.005). In the model predicting cRVEF, only left ventricular mass was a positive predictor of cRVEF (P <0.0001), while right ventricular mass (P <0.0001), PRF (P <0.0001), male sex (P <0.0001), and RV late gadolinium enhancement score (P = 0.008) were negative predictors of cRVEF. 
CONCLUSIONS Because PRF was inversely and independently correlated with LVEF, and LVEDV showed a positive and independent correlation with RVEF, left ventricular disease (low LVEF and LVEDV due to left ventricular compression) may be used as a marker of the severity of right ventricular disease (pulmonary regurgitation severity and its consequences). Further studies are needed to evaluate the role of LVEF and LVEDV in supporting patient selection for pulmonary valve replacement.