Aims: We aimed to assess interventricular and right-intraventricular dyssynchrony in patients after tetralogy of Fallot (TOF) repair by two-dimensional (2D) speckle tracking and to identify factors associated with dyssynchrony.
Methods and results: Forty-two patients after TOF repair with a mean age of 19.8 years and 42 age-matched healthy controls were studied. Longitudinal myocardial deformation (strain) and time-to-peak intervals were assessed by 2D speckle tracking and tissue Doppler imaging (TDI) in an apical four-chamber view. Dyssynchrony was defined as delay above 3 standard deviations of mean values in the control group. Magnetic resonance imaging (MRI) was performed for evaluation of ventricular function. Using 2D speckle tracking, 22 patients (52%) showed interventricular dyssynchrony and 16 (38%) had right-intraventricular dyssynchrony. The interventricular delay correlated significantly with right ventricular (RV) strain (r = 0.687, P < 0.001), RV systolic pressure (r = 0.535, P = 0.001), QRS duration (r = 0.466, P = 0.002), RV end-diastolic (r = 0.377, P = 0.018), and RV end-systolic volumes (r = 0.452, P = 0.004) as well as RV ejection fraction (r = -0.378, P = 0.018). Similarly, the right-intraventricular delay correlated significantly with RV strain (r = 0.534, P < 0.001), QRS duration (r = 0.428, P = 0.005), RV end-systolic volume (r = 0.34, P = 0.038), and RV systolic pressure (r = 0.413, P = 0.015). In multivariate regression analysis, reduced RV strain and prolonged QRS duration remained the main determinant factors predicting dyssynchrony. Moreover, 2D speckle tracking and TDI showed a significant correlation in the assessment of the interventricular (r = 0.738, P < 0.001) and right-intraventricular delay (r = 0.747, P < 0.001).
Conclusion: Interventricular and right-intraventricular dyssynchrony are detectable in patients after TOF repair by 2D speckle tracking. Reduced RV myocardial deformation and QRS prolongation are the main factors associated with the observed dyssynchrony.