The Impact of Obesity on Cardiac Energy Metabolism and Efficiency in Heart Failure With Preserved Ejection Fraction

The incidence and prevalence of heart failure with preserved ejection fraction (HFpEF) continues to rise, and now comprises more than half of all heart failure cases. There are many risk factors for HFpEF, including older age, hypertension, diabetes, dyslipidemia, sedentary behaviour, and obesity. The rising prevalence of obesity in society is a particularly important contributor to HFpEF development and severity. Obesity can adversely affect the heart, including inducing marked alterations in cardiac energy metabolism. This includes obesity-induced impairments in mitochondrial function, and an increase in fatty acid uptake and mitochondrial fatty acid β-oxidation. This increase in myocardial fatty acid metabolism is accompanied by an impaired myocardial insulin signaling and a marked decrease in glucose oxidation. This switch from glucose to fatty acid metabolism decreases cardiac efficiency and can contribute to severity of HFpEF. Increased myocardial fatty acid uptake in obesity is also associated with the accumulation of fatty acids, resulting in cardiac lipotoxicity. Obesity also results in dramatic changes in the release of adipokines, which can negatively impact cardiac function and energy metabolism. Obesity-induced increases in epicardial fat can also increase cardiac insulin resistance and negatively affect cardiac energy metabolism and HFpEF. However, optimizing cardiac energy metabolism in obese subjects may be one approach to preventing and treating HFpEF. This review discusses what is presently known about the effects of obesity on cardiac energy metabolism and insulin signaling in HFpEF. The clinical implications of obesity and energy metabolism on HFpEF are also discussed.