Evaluation of Myocardial Triglyceride Accumulation Assessed on ¹H-Magnetic Resonance Spectroscopy in Apparently Healthy Japanese Subjects

OBJECTIVE: Proton magnetic resonance spectroscopy ((1)H-MRS) enables the clinician to noninvasively assess the amount of ectopic fat in the liver, skeletal muscle and myocardium. Recent studies have reported that the myocardial triglyceride (TG) content is associated with aging, metabolic disorders and cardiac dysfunction. However, the clinical usefulness of myocardial TG measurements in Japanese subjects has not been fully investigated. METHODS: The myocardial TG content was evaluated using (1)H-MRS in 37 apparently healthy Japanese subjects, and the left ventricular function was measured on cardiac magnetic resonance imaging (MRI). Blood pressure, body composition and biochemical markers were measured in a fasting state, and cardiopulmonary exercise testing (CPX) was performed to evaluate exercise capacity. RESULTS: The mean myocardial TG content was 0.85±0.40%. The myocardial TG content was significantly associated with the percent body fat (r=0.39), serum triglyceride level (r=0.40), estimated glomerular filtration rate (r=-0.37), anaerobic threshold (r=-0.36), maximal load of CPX (r=0.39), left ventricular end-diastolic volume (r=-0.41) and left ventricular end-systolic volume (LVESV) (r=-0.51) (all: p<0.05). In a multivariate analysis, the LVESV was found to be an independent factor of the myocardial TG content. CONCLUSION: (1)H-MRS may be useful for assessing the associations between the myocardial TG content and various clinical parameters, including those reflecting obesity, metabolic disorders, cardiac morphology and exercise capacity, noninvasively, even in Japanese subjects.