Early Marker of Regional Left Ventricular Deformation in Patients With Hypertrophic Cardiomyopathy Evaluated by MRI Tissue Tracking: The Effects of Myocardial Hypertrophy and Fibrosis

Purpose: To evaluate the regional left ventricular (LV) myocardial strain of early stage hypertrophic cardiomyopathy (HCM) patients by magnetic resonance (MR) tissue tracking. Materials and Methods: In all, 114 adult HCM patients classified as NYHA I or II and 32 healthy volunteers were enrolled and underwent 3.0T MR examination. Vertical 2-chamber long axis, horizontal 4-chamber, and short axis cine sequence as well as late gadolinium enhancement images (LGE) were scanned. The cardiac function, regional LV tissue tracking variables, end-diastolic wall thickness (EDTH), and LGE extent were measured. Results: In the HCM group, 38 were NYHA I and 76 were NYHA II. By regional analysis, peak strain (PS) and peak displacement (PD) with radial, circumferential direction of hypertrophic segments (n5283) were significantly lower than nonhypertrophic segments (n51541) (all P< 0.05). Radial PS was significantly correlated with LVEDTH (r520.467, P< 0.0001). Radial PD was negatively associated with LVEDTH (r520.331, P< 0.0001). The PS and PD of all directions were decreased in segments with LGE (n5723) compared with those without LGE (n51101) (all P< 0.05). In addition, radial PS and PD were negatively associated with LGE extent (radial PS, r520.441; radial PD, r520.274; both P< 0.0001). All strain parameters showed excellent inter-and intraobserver agreements. Conclusion: Decreased regional LV myocardial strain hypertrophic and fibrotic segments of early-stage HCM patients can be measured by MR tissue tracking based on routine cine images. Moreover, myocardial strain may decrease with the increasing of myocardial hypertrophy as well as fibrosis. Level of Evidence: 2 Technical Efficacy: Stage 3