Abstract
Management of diabetic patients with heart failure is a complex endeavor. The initial reluctance to use metformin in these patients has given way to a broader acceptance after clinical trials and meta-analyses have revealed that some of the insulin-sensitizing agents lead to adverse cardiovascular events. We have proposed that an increase of substrate uptake by the insulin-resistant heart is detrimental because the heart is already flooded with fuel. In light of this evidence, metformin offers a unique safety profile in the patient with diabetes and heart failure. Our article expands on the use of metformin in patients with heart failure. We propose that the drug targets both the source as well as the destination (in this case the heart) of excess fuel. We consider treatment of diabetic heart failure patients with metformin both safe and effective.