Torsional mechanics of the left ventricle in patients after surgical repair of tetralogy of Fallot

Abstract

Background: This study aimed to test the hypothesis that alteration of left ventricular (LV) torsional mechanics occurs in patients after repair of tetralogy of Fallot (TOF) and is associated with right ventricular (RV) volume overload and changes in LV configuration. Methods and Results: Fifty-five TOF patients aged 19.0±8.1 years and 27 age-matched healthy controls were studied. The LV and RV volumes were measured using 3-dimensional echocardiography while LV geometry was quantified by the diastolic eccentricity index (EI). The LV peak systolic torsion and systolic twisting and diastolic untwisting velocities were determined by speckle tracking. Compared with controls, patients had significantly greater RV end-systolic (P<0.001) and diastolic (P<0.001) volumes and LV diastolic EI (P<0.001). In contrast, LV peak apical rotation (P<0.001), systolic torsion (P=0.004), systolic twisting velocity (P=0.001), and diastolic untwisting velocity (P=0.001) were lower in patients than in controls. For the whole cohort, RV EDV and LV diastolic EI correlated negatively with peak systolic torsion, systolic twisting velocity, and diastolic untwisting velocity (all P≤0.001). Systolic torsion correlated strongly with diastolic untwisting velocity (r=0.72, P<0.001), while systolic twisting velocity correlated with LV ejection fraction (r=0.3, P=0.005). Conclusions: LV torsional mechanics is impaired and is negatively related to RV volume overload and LV eccentricity in patients after TOF repair.