Effect of Chronic Right Ventricular Volume Overload on Ventricular Interaction in Patients after Tetralogy of Fallot Repair

Background: Right ventricular (RV) volume overload results in RV dilatation and dysfunction in patients with pulmonary regurgitation after tetralogy of Fallot (ToF) repair, affecting left ventricular (LV) function because of ventricular interaction. The aim of this study was to assess the effect of chronic RV volume loading on LV myocardial mechanics inpatients after ToF repair by combining cardiac magnetic resonance imaging with echocardiography. Methods: Seventy-five subjects were studied: 50 patients after ToF repair and 25 age-matched controls. All patients with ToF and controls underwent echocardiography at the time of clinically indicated cardiac magnetic resonance imaging. Myocardial deformation, including LV torsion, was analyzed using speckle tracking echocardiography. Results: RV free wall global and segmental longitudinal strain and strain rate were significantly lower in patients with ToF compared with controls (P<.001). All LV longitudinal, strain, and torsion parameters were significantly reduced in patients with ToF (P<.01). Basal rotation was particularly abnormal, with 38% of patients with ToF having reversed basal rotation. In contrast, apical rotation was reduced but not reversed. On multivariate regression analysis, the only significant predictor of counterclockwise basal rotation was RV strain, suggesting that RV function more than dilatation influences abnormal LV torsion. Conclusion: Patients with ToF have abnormal LV myocardial mechanics, as demonstrated by speckle-tracking echocardiography. The most striking changes were noted in LV torsion, especially related to abnormal LV basal rotation. RV dysfunction seems the most important determinant of abnormal LV rotation. The clinical significance and potential prognostic implications of these observations remain to be determined.