To the Editor: Dr Ingelsson and colleagues1 studied the predictive impact of insulin resistance, measured by the euglycemic insulin clamp, on the incidence of congestive heart failure (CHF). High insulin resistance at baseline was the major parameter associated with subsequent development of CHF, independent of obesity and other established risk factors. These data are suggestive of a primary role of insulin resistance in the pathophysiology of CHF. In the search for mechanisms for this effect, the authors discuss the roles of increased formation of advanced glycosylation end products, sodium retention, activation of the sympathetic nervous system, and increased response to angiotensin II, all of which are associated with insulin resistance and impaired cardiac function.