Abstract 15618: Cardiac Magnetic Resonance Evaluation of Diastolic Indices in Boys With Duchenne Muscular Dystrophy

Abstract

Introduction: Cardiomyopathy (CM) is the leading cause of death in boys with Duchenne Muscular Dystrophy (DMD). Diastolic dysfunction precedes systolic dysfunction in DMD, but while CMR is used routinely to assess fibrosis and left ventricular ejection fraction (LVEF), CMR measures of DMD diastolic dysfunction have not been reported. Hypothesis: Boys with DMD have diastolic dysfunction based on CMR indices when compared with healthy controls. Methods: Prospectively enrolled DMD patients (n = 54) and healthy male controls (n = 40) underwent CMR. Standard volumes and function were calculated. LV filling curves were generated by contouring every phase in the short axis. Indices were compared between groups using a Wilcoxon rank sum and within DMD using a Spearman’s rho test. Results: There was no difference in LVEF between DMD and controls, though DMD patients had significantly smaller indexed left ventricular end diastolic volume (LVEDVi) (see data in Table 1). Peak ventricular filling rates (PFR) were significantly slower in DMD vs controls as were peak ventricular emptying rates (PER). Mean time to PFR (tPFR) and mean time to PER (tPER) were significantly shorter in DMD patients vs controls. In a subset analysis excluding patients with LVEF < 55%, observed differences in PFR, PER, tPFR and TPER remain statistically significant. In DMD patients, tPER correlates negatively with LVEF (rho = -0.57, p <0.001). PER corrected to LVEDVi correlated strongly with LVEF (rho = 0.74, p <0.001). PFR corrected to LVEDVi also correlated strongly with LVEF (rho = 0.75, p <0.001). Conclusions: Despite having normal baseline systolic function, boys with DMD have significantly different CMR diastolic indices compared with controls. CMR diastolic indices may help detect subclinical dysfunction in DMD. Future analyses should evaluate for correlation between diastolic dysfunction and clinical outcomes.