Water-suppressed one-dimensional 1H NMR chemical shift imaging of the heart before and after regional ischemia

The effect of rosiglitazone on integrated cardiovascular performance, cardiac structure, function and myocardial triglyceride: trial design and rationale

The thiazolidinedione (TZD) class of medications has been associated with increased risk for peripheral oedema, as well as incident and worsening heart failure (HF). The mechanism of these observed effects remains unclear. Here we present the rationale and study design for a randomised clinical trial designed to evaluate the cardiac effects of rosiglitazone on integrated cardiovascular performance, cardiac structure and function. The study is a randomised, single-centre, double-blind, placebo-controlled, parallel-group clinical trial to evaluate the effect of rosiglitazone on integrated cardiovascular performance in a cohort of patients with type 2 diabetes mellitus (T2DM) at increased risk for developing heart failure (HF). Participants will be randomised to receive rosiglitazone or matching placebo for six months. All subjects will undergo maximal treadmill cardiopulmonary exercise testing at baseline and after six months on study drug, with the primary trial end point of peak oxygen uptake indexed to fat-free mass (VO 2peak-FFM). Approximately two-thirds of the study cohort will undergo cardiac magnetic resonance imaging (MRI) and spectroscopy (MRS) at baseline and after six months of study therapy to assess cardiac structure, function and myocardial triglyceride content. While concerns for peripheral oedema and HF continue to confound clinical use of TZD medications, the direct cardiac effects of these drugs remain poorly understood and the clinical relevance of these clinical observations remains unclear. The present study will combine a series of state-of-the-art assessments to evaluate the cardiac effects of rosiglitazone treatment.

Myocardial triglycerides and systolic function in humans: in vivo evaluation by localized proton spectroscopy and cardiac imaging

Recent experimental data suggest that adiposity directly damages the heart by promoting ectopic deposition of triglyceride, a process known as myocardial steatosis. The goal of this study was to develop and validate proton magnetic resonance spectroscopy ((1)H MRS) as an in vivo tool to measure myocardial lipid content. Complementary studies in rat tissue ex vivo and in 15 healthy humans in vivo provided evidence that (1)H MRS constitutes a reproducible technique for the measurement of myocardial triglyceride. In myocardial tissue from Zucker rats, the (1)H MRS measurement of triglyceride matched that obtained by biochemical measurement (P < 0.001). In human subjects triglyceride was evident in the hearts of even the very lean individuals and was elevated in overweight and obese subjects. Increased myocardial triglyceride content was accompanied by elevated LV mass and suppressed septal wall thickening as measured by cardiac imaging.