Abstract 13256: Patients With Repaired Tetralogy of Fallot have Multiple Forms of Dyssynchrony in the Heart: A Cine Cardiac Magnetic Resonance Study
Background: [[Unable to Display Character: –]] Patients with repaired tetralogy of Fallot (rTOF) often develop ventricular systolic dysfunction. Although these patients frequently have right bundle branch block, the contribution of cardiac dyssynchrony to dysfunction remains controversial. To better understand this phenomenon and ultimately study therapies, we developed a method to quantify left (LV), right (RV) and inter-ventricular cardiac dyssynchrony using standard cine MRI.
Methods: [[Unable to Display Character: –]] 25 patients with rTOF (age 29±16) and 17 healthy controls (age 29±7) underwent cine cardiac MRI. Patients were imaged twice to assess inter-test reproducibility. Circumferential strain vs time curves were generated with a custom feature tracking algorithm for 12 LV and 12 RV segments in 3-7 slices encompassing the ventricles. For each segment, the temporal offset of the strain curve relative to a global LV reference curve derived from the controls was calculated and expressed as a percent of the cardiac cycle. The intra-ventricular dyssynchrony index (DI) for each ventricle was computed as the inter-quartile range of the temporal offsets (more dyssynchrony creates a wider range of temporal offsets). The inter-ventricular DI was calculated as the difference in median RV and median LV temporal offsets.
Results: [[Unable to Display Character: –]]Inter-test reproducibility for the three DIs was good with all coefficients of variation ≤21%. Compared to controls, patients had a greater LV DI (6±2% vs 3±1%, p<0.001) and a similar RV DI (7±2% vs 8±3%, p=0.27). Patients had a greater inter-ventricular DI with the RV contracting 4±4% later than the LV vs 1±4% earlier in controls (p<0.001). Patients had early septal contraction with delayed LV and RV free wall contraction (Figure).
Conclusions: [[Unable to Display Character: –]]Patients with repaired tetralogy of Fallot have multiple types of cardiac dyssynchrony which can be quantified from standard cine MRI with good inter-test reproducibility. Future studies need to determine whether these patients may benefit from resynchronization.
- Cardiac MRI
- Intraventrocular dysshynchrony
- Tetralogy of Fallot
- Pediatric cardiology
- Congenital heart disease
- © 2013 by American Heart Association, Inc.