Relationships Between Regional Left Ventricular Myocardial Strain and Tissue Characteristics in Hypertrophic Cardiomyopathy.

Both fibrosis and hypertrophy contribute to abnormal myocardial mechanics in hypertrophic cardiomyopathy (HCM). We sought to assess the relationships between regional structural and functional parameters in HCM by cardiac magnetic resonance (CMR). This was a retrospective single-center study of HCM patients and age-matched controls with either hypertensive heart disease (HHD) or normal CMRs. CMR feature tracking was performed to assess global and segmental 2D-radial, circumferential, and longitudinal LV strain, while native and post-contrast T1 parametric mapping analysis was performed to assess the global and regional T1 values and ECV fraction. Of 100 patients (age 56 ± 15 years; 66% male), 62 were in the HCM group and 38 in the control group (19 healthy individuals and 19 with HHD). Compared to the control group, global circumferential strain (-16.1 ± 5.9% vs. -20.8 ± 3.6%, p < 0.001) and radial strain (45.2 ± 14.1% vs. 32.1 ± 14.0%, p < 0.001) were worse in the HCM group. Among the HCM patients, there were significant correlations between segmental native T1 values at the most hypertrophied segment and global longitudinal strain (r = 0.27, p = 0.031), global circumferential strain (r = 0.34, p = 0.006), global radial strain (r = -0.29, p = 0.024), and left ventricular ejection fraction (LVEF) (r = -0.31, p = 0.014). In HCM, higher myocardial T1 at the most hypertrophied segment correlated with worse global LV myocardial strain and LVEF by CMR.