Cardiac rest and stress metabolism in patients with type 2 diabetes

Patients with type 2 diabetes (T2D) are at significant risk of developing heart failure and related complications. Altered myocardial fuel selection may play a central role in cardiac disease risk in patients with T2D by affecting myocardial oxygen demand and metabolic flexibility. At any given level of cardiac work, an increased dependence on fatty acids (FA) relative to carbohydrates decreases cardiac efficiency, which may adversely affect cardiac function.

We aim to evaluate, in vivo, the effect of T2D on myocardial energy metabolism and metabolic flexibility. We will investigate whether patients with T2D have a metabolically inflexible myocardium with a fixed FA preference which is unable to increase the use of glucose even in response to acute increases in cardiac workload. We will also determine whether the fixed preference to use FA significantly contributes to abnormalities in contractile function. We will carry out a cross-sectional, case-control study among 22 patients with type 2 diabetes and 22 people without diabetes who have preserved cardiac function. Significant coronary artery disease will be excluded in all patients by coronary angiography. Myocardial metabolism will be determined at baseline and during dobutamine stress with measurement of transmyocardial arteriovenous differences of oxygen and metabolites. Participants will undergo a comprehensive evaluation of cardiac structure, function and perfusion using rest and dobutamine stress cardiovascular magnetic resonance tests.

Our findings will help us gain a greater understanding of why patients with type 2 diabetes are at significant risk of developing heart failure.