Abstract 19670: Association Between Myocardial T1-Mapping and Left Ventricular Mechanics in Patients With Repaired Tetralogy of Fallot
Introduction: Patients with repaired tetralogy of Fallot (TOF) have progressive, adverse ventricular remodeling, leading to abnormal contractile mechanics. Defining the mechanisms underlying this dysfunction, such as diffuse fibrosis, may provide insights into poor long-term outcomes.
Hypothesis: Left ventricular (LV) diffuse fibrosis is related to impaired LV mechanics (strain/strain rate).
Methods: Forty-three patients with TOF were evaluated with cardiovascular magnetic resonance (CMR) utilizing T1-mapping with a modified Look-Locker sequence at 3 short axis levels and spiral cine Displacement Encoding (DENSE) at the same positions to assess strain & strain rate. Native and post-contrast T1, partition coefficient, and extracellular volume fraction (ECV; using a bloodpool T1-derived hematocrit) were computed for the LV. Linear correlations were computed using Spearman’s rho. Significance was p<0.05.
Results: Four patients were excluded due to image quality or movement. 39 patients (26±10 years, 56% male) were included. Compared to normal values, seven patients had elevated ECV (>0.285), while 12 had impaired circumferential strain (<14.4%); only one patient had both. Fibrosis and mechanics data are reported in the Table. Linear associations between fibrosis and mechanics included partition coefficient with apical radial strain (R = -0.45, p = 0.006) and post-contrast T1 with basal diastolic strain rate (Figure).
Conclusions: After TOF repair, diffuse fibrosis and impaired mechanics develop in the LV. The greater prevalence of impaired mechanics and weakness of their associations suggest mechanical dysfunction may be independent of diffuse fibrosis in TOF.
Author Disclosures: C.M. Haggerty: None. A. Mejia-Spiegeler: None. J.D. Suever: None. G.J. Wehner: None. E. Kim: None. B.K. Fornwalt: None. M.A. Fogel: Research Grant; Modest; R01 HL098252.
- © 2016 by American Heart Association, Inc.