Purpose: The aim of this study is to assess differences in myocardial features in patients with HCM with asymmetric or without asymmetric hypertrophy.
Method: Cardiac and proton magnetic resonance spectroscopy were performed to assess LV function, wall thickness, LV mass, extent of late gadolinium enhancement (LGE), and myocardial triglyceride (MTG) content in the septum of 32 patients diagnosed with HCM. Patients were divided into two groups: with or without asymmetric hypertrophy (ASH and non- ASH groups, respectively). Asymmetric hypertrophy was defined as asymmetric septal hypertrophy (ASH), which is measured as =1.3 of the echocardiographic interventricular septum to LV free wall thickness ratio.
Result: Sixteen patients had ASH. LGE was detected in 20 patients with HCM, whereas LGE in the septum was detected in 12. Although no significant difference in MTG content was found between patients with (1.55% ± 1.03%) and without (1.03% ± 0.83%) septal LGE in the non-ASH group, a significant difference was observed in the MTG content between patients with (0.58% ± 0.22%) and without (1.29% ± 0.73%) septal LGE in the ASH group (P = 0.03). In the non-ASH group, MTG content was not significantly associated with LV mass and diastolic parameters. Conversely, MTG content was significantly associated with LV mass (r = -0.49, P = 0.03) in the ASH group.
Conclusion: The association between LGE and MTG was different in patients with HCM with or without ASH. Our data suggested that the MTG metabolism of the septum in HCM may be different based on the absence or presence of asymmetric hypertrophy.