Effects of exercise training on neurovascular control in heart failure patients treated with Carvedilol

Evidence suggests that carvedilol decreases muscle sympathetic nerve activity (MSNA) in patients with heart failure(HF) but carvedilol fails to improve forearm vascular resistance and overall functional capacity. Exercise training in HF reduces MSNA and improves forearm vascular resistance and functional capacity. The aim of study was to investigate whether exercise training in the presence of carvedilol maintains its beneficial effects on MSNA, forearm blood flow and functional capacity. Twenty seven HF patients, Functional Class II III(NYHA), EF<35%, peak VO2 <20ml/kg/min, treated with carvedilol were randomly divided into two groups: exercise training(n=15) and untrained(n=12). MSNA was recorded by microneurography. Forearm blood flow(FBF) was measured by venous occlusion plethysmography. The four-month training program consisted of three 60-min exercise/week on cycloergometer. Baseline parameters were similar between groups. Exercise training reduced MSNA (-14 ± 3.3bursts/100HB, p<0.01) and increased FBF (0.6 ± 0.1 ml.min-1.100ml-1, p<0.01) in HF patients on carvedilol. In addition, exercise training improved peak VO2 in HF patients (20 ± 6%, p=0.05). MSNA, FBF and peak VO2 were unchanged in untrained HF patients on carvedilol. In conclusion, exercise training reduces MSNA in heart failure patients treated with carvedilol. In addition, the beneficial effects of exercise training on muscle blood flow and functional capacity are still realized in patients on carvedilol.