Myocardial Strain and DMD-associated Cardiac Disease
In DMD-CM, myocardial strain, an indicator of local myocardial deformation can detect occult cardiac disease early in the course of DMD despite normal LVEF 32, 38, 48, 107. It has been shown that CMR derived εcc is an early robust indicator of cardiac dysfunction and can detect occult ventricular dysfunction in young DMD patients with normal EF (>55%)48, 49, 53, 54, 107. CMR-derived peak left ventricular circumferential strain (εcc) is abnormal early in DMD despite normal EF, and further depressed εcc magnitude is associated with development of overt cardiac dysfunction and presence of myocardial fibrosis 108. The decrease in εcc despite preserved EF, suggest greater sensitivity of εcc for disease detection compared to LVEF. Thus, εcc is a sensitive, reliable biomarker of both subtle and overt cardiac dysfunction in DMD then LVEF82.