Functional electrical stimulation improves endothelial function and reduces peripheral immune responses in patients with chronic heart failure

Abstract

Previous studies have shown beneficial effects of functional electrical stimulation (FES) on muscle performance and exercise capacity of patients with chronic heart failure. This study evaluates the impact of FES on endothelial function and peripheral markers of immune activation in patients with moderate to severe heart failure. Twenty-four patients with a left ventricular ejection fraction of less than 40% and New York Heart Association class II-III symptoms, undergoing optimized drug therapy, were randomly assigned (2 : 1) to a 6-week training programme of FES (n=16) or served as controls (n=8). Endothelial function was assessed by Doppler flow-mediated dilatation (FMD) of the brachial artery before and after the training programme. Peripheral pro-inflammatory/anti-inflammatory markers such as tumour necrosis factor (TNF)-alpha, interleukin (IL)-6, soluble intercellular adhesion molecule (sICAM)-1, soluble vascular cell adhesion molecule (sVCAM)-1 and IL-10 were also measured before and after training. A significant improvement on the 6-min walk test (7.5+/-3.3%), Minnesota Living Score (18.2+/-8.6%) and FMD (38.5+/-15.1%) was observed only in the FES-treated group. FES also causes a significant reduction of TNF-alpha (-11.5+/-8.9%), sICAM-1 (-13.1+/-9.8%), and sVCAM-1 (-10.6+/-6.6%), as well as a respective increase in the ratio IL-10/TNF-alpha (37.1+/-29.4%). In the FES group, the percentage improvement in the Minnesota Living Score was significantly correlated with respective changes in circulating TNF-alpha (r=0.624, P<0.01), sVCAM-1 (r=0.665, P<0.001) and the ratio IL-10/TNF-alpha (r=-0.641, P<0.01). FES is an exercise training programme that improves endothelial function in patients with chronic heart failure, and also has anti-inflammatory effects.