Myocardial Triglyceride Content and Late Gadolinium Enhancement in Hypertrophic Cardiomyopathy with Asymmetric Septal Hypertrophy

Abstract Asymmetric septal hypertrophy (ASH) is the most common phenotype of hypertrophic cardiomyopathy (HCM). However, the difference between myocardial metabolism and myocardial features such as myocardial fibrosis and myofiber disarray in HCM remains unclear. Cardiac magnetic resonance (CMR) and proton magnetic resonance spectroscopy (1H-MRS) were performed on 16 patients diagnosed as HCM with ASH to assess the differences in myocardial features and morphology. There were 7 patients who had LGE in ASH localized with the voxel of 1H-MRS. The LV ejection fraction was significantly lower in the LGE (+) group than in the LGE (−) group (64.8% ± 4.9% vs. 72.1% ± 3.8%, P = 0.004). LV end-systolic volume was significantly greater in the LGE (+) group than in the LGE (−) group (51 ± 11 ml vs. 33 ± 12 ml, P = 0.007). A significant difference in MTG content was observed between patients in the LGE (+) group and in the LGE (−) group (0.58% ± 0.22% vs 1.29% ± 0.73%, P = 0.03). MTG content was significantly associated with LV ejection fraction, LV end systolic volume, and LV mass. In multivariate analyses, LV ejection fraction had an independent association with MTG content (P = 0.01) Our data suggest that the metabolism of the septum in HCM with ASH may be different based on the absence or presence of LGE and that measurement of MTG content by 1H-MRS may be useful to evaluate the characteristics of myocardial metabolic changes caused by the LV remodeling process in HCM. (248 words)