Association between left ventricular mechanics and diffuse myocardial fibrosis in patients with repaired Tetralogy of Fallot: A cross-sectional study

Background: patients with repaired tetralogy of fallot (tof) have progressive,adverse biventricular remodeling,leading to abnormal contractile mechanics. defining the mechanisms underlying this dysfunction,such as diffuse myocardial fibrosis,may provide insights into poor long-term outcomes. we hypothesized that left ventricular (lv) diffuse fibrosis is related to impaired lv mechanics. methods: patients with tof were evaluated with cardiac magnetic resonance in which modified look-locker (molli) t1-mapping and spiral cine displacement encoding (dense) sequences were acquired at three lv short-axis positions. linear mixed modeling was used to define the association between regional lv mechanics from dense based on regional t1-derived diffuse fibrosis measures,such as extracellular volume fraction (ecv). results: forty patients (26 ± 11 years) were included. lv ecv was generally within normal range (0.24 ± 0.05). for lv mechanics,peak circumferential strains (-15 ± 3%) and dyssynchrony indices (16 ± 8 ms) were moderately impaired,while peak radial strains (29 ± 8%) were generally normal. after adjusting for patient age,sex,and regional lv differences,ecv was associated with log-adjusted lv dyssynchrony index (β = 0.67) and peak lv radial strain (β = -0.36),but not lv circumferential strain. moreover,post-contrast t1 was associated with log-adjusted lv diastolic circumferential strain rate (β = 0.37). conclusions: we observed several moderate associations between measures of fibrosis and impaired mechanics,particularly the lv dyssynchrony index and peak radial strain. diffuse fibrosis may therefore be a causal factor in some ventricular dysfunction in tof. © 2017 the author(s).