Myocardial Fibrosis Evaluated by T1 Mapping and Its Relationship to Left Ventricular Hypertrophy, Strain, and T2 Value in Hypertrophic Cardiomyopathy Without Late Gadolinium Enhancement

PURPOSE: The aim of this study was to evaluate T1 and T2 values and to investigate their association with left ventricular (LV) hypertrophy and strains in hypertrophic cardiomyopathy (HCM) without late gadolinium enhancement (LGE). MATERIALS AND METHODS: Forty-eight HCM patients without LGE and 20 age-matched and sex-matched healthy subjects who underwent 3.0 T cardiovascular magnetic resonance imaging (CMR) were enrolled. Cine, T1, and T2 mapping and LGE sequencing were conducted. Unpaired t test, Mann-Whitney U test, χ 2 test, Spearman correlation analysis, and univariable and multivariable linear regression were performed in this study. RESULTS: Patients with HCM without LGE had a relatively higher global circumferential strain (GCS) than the control group (-19.82% -21.81%, -17.52% vs -17.48% ± 3.42; P = 0.020). In contrast, the global longitudinal strain (GLS) in HCM patients without LGE was lower than that in the control group (-12.07% ± 2.89 vs -13.93% ± 3.03; P = 0.021). In addition, native T1 values, extracellular volume (ECV), and T2 values were elevated in HCM patients without LGE compared with those in the control group (all P < 0.05). Moreover, higher native T1 values were associated with elevated T2 values (r = 0.301, P = 0.038). LV mass index (β = 0.375 95% CI: 8.107 to 35.151, P = 0.002) and GCS (β = 0.623 95% CI: 0.974 to 2.883, P < 0.001) were independently associated with elevated LV ejection fraction when max LV wall thickness, T2 value, global radial strain (GRS), and GLS were added to the multivariate regression model. CONCLUSIONS: In HCM without LGE, elevated T1, T2, and ECV values and reduced GLS occurred despite preserved LV ejection fraction. These findings demonstrate that myocardial interstitial fibrosis and cellular edema may precede the early stages of HCM.