Abstract 1938: LV Dyssynchrony Measured by MRI Speckle Tracking is Associated With VT and Death in Repaired Tetralogy of Fallot
Introduction: Factors such as LV and RV dysfunction and RV dilation have been shown to be associated with poor long-term outcomes in tetralogy of Fallot (TOF). In other patient populations, left ventricular dyssynchrony has been related to LV dysfunction, valvar regurgitation, and death. This project sought to test the hypothesis that LV dyssynchrony assessed by MRI-derived tissue (speckle) tracking in TOF patients is associated with subsequent ventricular tachycardia (VT) and death.
Methods: In this single-center retrospective analysis, inclusion criteria were repaired TOF and MRI between 2000 –2008. The study group comprised 13 patients with history of death or VT. The control group (repaired TOF, no death or VT), matched by age and last surgical procedure, comprised 26 patients. Demographic and ECG data were recorded. For the dyssynchrony analysis, MRI short-axis cine SSFP data were analyzed by tissue (speckle) tracking of the endocardial border using Syngo VVI software, with the LV divided into 6 segments. LV dyssynchrony was evaluated using the following parameters; maximum time difference to peak displacement (D), circumferential strain (CS), and radial strain (RS); and standard deviation in the time to peak values (STD-D, STD-CS, STD-RS).
Results: There were no differences between the death/VT and control groups in gender; mean age at MRI and age at TOF repair; NYHA class; QRS duration; and presence of right bundle branch block. Differences were found between death/VT and control groups in: RVEDVi (median 187.6 vs 125.3 mL/m2, p=0.01), RVEF (39 vs 51%, p<0.01), and LVEF (49 vs 60%, p=0.03). The table⇓ summarizes differences between groups in dyssynchrony measurements. In the multivariate model, the maximum difference in time to peak CS was the best discriminator of outcome (p=0.04).
Conclusions: Speckle tracking applied to MRI images in repaired TOF patients identifies differences in LV synchrony that relate to death and VT.