Effect of insulin sensitivity on severity of heart failure

Insulin resistance is associated with various cardiac dysfunctions both molecularly and clinically, including cardiac muscle relaxation and blood flow. Although, these dysfunctions result in heart failure, relationship between insulin resistance and severity of heart failure is not well studied yet. Since severity of chronic heart failure can be determined by exercise tolerance, we attempted to assess the insulin resistance in patients with chronic heart failure and evaluated the relationship between insulin sensitivity and exercise tolerance. We examined nine chronic heart failure patients. Insulin sensitivity was determined with euglycemic hyperinsulinemic clamp technique. Exercise tolerance was assessed using cardiopulmonary exercise testing. There was no correlation between body mass index and insulin sensitivity, while between body fat ratio, significant negative correlation was investigated (r = −0.463). Insulin sensitivity was negatively correlated with exercise tolerance (with anaerobic threshold, r = 0.548; with peak oxygen uptake, r = 0.581). Insulin sensitivity also showed significant positive correlation with cardiac function during exercise (GIR versus peak oxygen pulse: r = 0.535). Insulin sensitivity is revealed to have some effects on exercise tolerance and cardiac function in patients with chronic heart failure. Insulin resistance seems to be one of the important targets in managing the chronic heart failure.