Abstract 16905: Relationship Between Cardiac Magnetic Resonance Derived Regional Systolic Strain and Myocardial Tissue Characteristics in Children With Duchenne Muscular Dystrophy

Abstract

Background: Duchenne Muscular dystrophy (DMD) is an X linked disorder associated with deterioration in cardiac function. Identification of subclinical abnormalities using cardiac magnetic resonance (CMR) may provide an earlier marker to trigger therapy. We aimed to correlate regional left ventricle (LV) myocardial native T1 and extracellular volume (ECV) with regional strain in children with DMD. Methods: Fourteen boys with DMD (median 14 years, range 9-18) underwent CMR to measure segmental native T1 and ECV at the basal and mid-ventricular level. Native T1 and ECV were measured from the MOLLI sequence using cvi42 software. Circumferential (CS) and longitudinal (LS) strain values were assessed in the corresponding cine images using an in-house developed, semi-automated deformation technique. Associations of T1 and ECV with strain were examined using Pearson correlation coefficient. Results: The majority had LVEF >50% (79%). Median global basal CS (-20.5%) and mid-cavity CS (-18.9%) were normal, but the global LS was reduced (-15.2%). Regions with LGE and CS abnormalities were similar (inferior and inferolateral) but differed from regions with increased T1 & ECV (inferoseptal, anteroseptal) and LS abnormalities (inferoseptal and anteroseptal). CS and LS abnormalities were noted more in mid-cavity than basal segments. There were strong correlations between lower CS and higher native T1 in four segments, and correlations with higher ECV in all segments (Table 1). LS showed no correlations with either native T1 or ECV. Conclusions: Native T1 and ECV abnormalities were noted in segments not associated with positive LGE. The relationship between native T1, ECV and CS suggest that regional diffuse fibrosis is associated with subclinical systolic dysfunction and is detectable on CMR prior to global abnormalities. These findings may provide evidence for early medical therapy aimed at delaying cardiac dysfunction in DMD.