Context: An association has been suggested between elevated plasma non-esterified fatty acid (NEFA) levels, myocardial triglyceride accumulation and myocardial function.

Objective: To investigate the effects of an elevation of plasma NEFA by a high fat, high energy(HFHE) diet on hepatic and myocardial triglyceride accumulation, and on myocardial function.

Design: Fifteen healthy males (mean ± SD age: 25.0 ± 6.6 years) were subjected to a 3-day HFHE diet consisting of their regular diet, supplemented with 800 ml of cream (280g fat) every day.

Methods: ¹H-MR spectroscopy was performed for assessing hepatic and myocardial triglycerides. Furthermore, left ventricular function was assessed using MR imaging.

Results: The HFHE diet increased hepatic triglycerides compared to baseline (from 2.01 ± 1.79 to 4.26 ± 2.78%, (p=0.001)) in parallel to plasma triglycerides and NEFA. Myocardial triglycerides did not change (0.38 ± 0.18 vs. 0.40 ± 0.12%, p=0.7).

The HFHE diet did not change myocardial systolic function. Diastolic function, assessed by dividing the maximum flow across the mitral valve of the early diastolic filling phase, by the maximum flow of the atrial contraction (E/A ratio), decreased compared to baseline (from 2.11 ± 0.39 to 1.89 ± 0.33 p=0.031). This difference was no longer significant after adjustment for heart rate (p=0.12).

Conclusions: Short term HFHE diet in healthy males results in major increases in plasma triglyceride and NEFA concentrations and hepatic triglycerides, whereas it does not influence myocardial triglycerides or myocardial function. These observations indicate differential, tissue-specific partitioning of triglycerides and/or fatty acids among non-adipose organs during HFHE diet.