Myocardial tissue characteristics assessed by multiparametric CMR in hyperthyroid patients with suspected cardiac involvement

Abstract

Hyperthyroidism is reportedly associated with increased cardiovascular risk and heart failure. However, a definite association between hyperthyroidism and cardiomyopathy has not been reported. This study aimed to analyze alterations in myocardial tissue characteristics and strain, and to fill the knowledge gap about identifying cardiac involvement in patients with hyperthyroidism. In this single-center retrospective study, we enrolled 41 hyperthyroid patients who received clinically indicated cardiac magnetic resonance (CMR) examinations due to suspected cardiac involvement (including cardiac symptoms, electrocardiographic abnormalities or elevated cardiac biomarkers), together with 31 healthy volunteers who served as controls. All participants underwent standardized CMR scanning. Compared with controls, hyperthyroid with suspected cardiac involvement had significantly higher myocardial native T1 values (1301.8 ± 38.5 ms vs. 1270.0 ± 19.6 ms, P  < 0.001). The difference remained significant after adjusting for heart rate, age, sex and BMI (adjusted difference = 20.89 ms, 95% CI 3.08–38.71, P  = 0.022). No intergroup differences were found in left ventricular T2, global myocardial strain, left ventricular mass or LVEF. Exploratory correlation analyses in the hyperthyroid group revealed positive correlations of ECV with free triiodothyronine (FT3, r  = 0.445, 95% CI 0.142–0.672, P  = 0.006) and total triiodothyronine (TT3, r  = 0.363, 95% CI 0.044–0.615, P  = 0.027). After adjustment for haematocrit, age, heart rate, and BMI, the associations were attenuated (ECV-FT3: r  = 0.357, 95% CI:0.037–0.610; P  = 0.030; ECV-TT3: r  = 0.304, 95% CI: -0.023-0.571; P  = 0.068). T1-mapping can detect myocardial tissue alterations among hyperthyroid patients with clinical suspicion of cardiac involvement. Not applicable.