Diastolic dysfunction is associated with altered myocardial metabolism in asymptomatic normotensive patients with well-controlled type 2 diabetes mellitus

OBJECTIVES This study evaluated myocardial function in relation to high-energy phosphate (HEP) metabolism in asymptomatic patients with uncomplicated type 2 diabetes mellitus using magnetic resonance (MR) techniques. BACKGROUND Myocardial dysfunction may occur in patients with type 2 diabetes mellitus in the absence of coronary artery disease or left ventricular (LV) hypertrophy. The mechanisms underlying this diabetic cardiomyopathy are largely unknown, but may involve altered myocardial energy metabolism. METHODS We assessed myocardial systolic and diastolic function and HEP metabolism in 12 asymptomatic normotensive male patients with recently diagnosed, well-controlled type 2 diabetes and 12 controls, using MR imaging and phosphorus-31-nuclear MR spectroscopy (P-31-MRS) on a 1.5 T clinical scanner; P-31-MR spectra were quantified, and myocardial HEP metabolism was expressed as phosphocreatine to adenosine-triphosphate (PCr/ATP) ratio. RESULTS No differences were found in LV mass and systolic function between patients and controls. However, early (E) acceleration peak, deceleration peak, peak filling rate, and transmittal early-to-late diastolic peak flow (E/A) ratio, all indexes of diastolic function, were significantly decreased in patients compared with controls (p < 0.02). In addition, myocardial PCr/ATP in patients was significantly lower than in controls (1.47 vs. 1.88, p < 0.01). Inverse associations were found between myocardial PCr/ATP and E acceleration peak, E deceleration peak, and E peak filling rate (all, p < 0.05). CONCLUSIONS These results indicate that altered myocardial energy metabolism may contribute to LV diastolic functional changes in patients with recently diagnosed, well-controlled and uncomplicated type 2 diabetes. (C) 2003 by the American College of Cardiology Foundation.