Three-dimensional speckle tracking echocardiography in the assessment of right ventricular dysfunction after surgical repair of tetralogy of Fallot.

Background: The combined effects of preoperative hypertrophy and hypoxia, possible intraoperative myocardial damage, type of reconstruction, and acquired postoperative lesions such as pulmonary regurgitation may result in impaired RV deformation in post-operative tetralogy of Fallot (TF). Recently 3D speckle tracking echocardiography (3DSTE) has been proposed to assess mechanical dyssynchrony in these patients but the role of electromechanical dysfunction is not completely clear. Methods: Sixteen patients after TF repair (aged 17-53years) with dilated right ventricle, right bundle branch block (QRS >120ms), and NYHA class I or greater were studied with twodimensional and three-dimensional speckle tracking echocardiography. Right ventricular enddiastolic and end-systolic volumes were measured from three-dimensional datasets and right ventricular ejection fraction (3D-RVEF) was obtained. Right intraventricular dyssynchrony was determined as the difference between the longest and shortest electromechanical coupling times in the basal septal and lateral RV segments. Interventricular dyssynchrony was determined as the difference between electromechanical coupling times in the basal lateral LV segment and the most delayed RV segment. Sixteeen age-matched healthy subjects were selected as controls. Results: Right intraventricular dyssynchrony (77.1+/-24.2ms vs 13.1+/-8.9ms) and interventricular dyssynchrony (74.7+/-22.2ms vs 11.4+/-7.9ms) were shown in patients compared to normal controls. Right intraventricular dyssynchrony correlated with RV longitudinal strain (r=0.62, p<0.005), 3D RV end-systolic volume (r=0.47, p=0.02), and QRS duration (r=0.39, p=0.03). Interventricular dyssynchrony correlated with RV longitudinal strain (r=0.73, p<0.001), RV systolic pressure (r=0.59, p<0.005), 3D-RVEF (r=0.53, p=0.003), and QRS duration (r=-0.44, p=0.031). Reduced RV strain, 3D-RVEF and prolonged QRS duration were the main determinant factors predicting RV dyssynchrony by multivariate analysis. On ROC curves RV strain and 3DRVEF had optimal predictive accuracy of the NYHA functional class and a larger area under the receiver operating characteristic curve than the QRS duration. Conclusions: In patients with repaired TF RV dyssynchrony is associated with reduced 3D-RVEF and RV 3DSTE parameters.