Exercise training reduces sympathetic nerve activity in heart failure patients treated with carvedilol.
BACKGROUND
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.


OBJECTIVE
To investigate whether the beneficial effects exercise training on MSNA are maintained in the presence of carvedilol.


RESULTS
Twenty seven HF patients, NYHA Class II-III, EF <35%, peak VO(2) <20 ml/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 a cycloergometer. Baseline parameters were similar between groups. Exercise training reduced MSNA (-14+/-3.3 bursts/100 HB, p=0.001) and increased forearm blood flow (0.6+/-0.1 mL/min/100 g, p<0.001) in HF patients on carvedilol. In addition, exercise training improved peak VO(2) in HF patients (20+/-6%, p=0.002). MSNA, FBF and peak VO(2) were unchanged in untrained HF patients on carvedilol.


CONCLUSIONS
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.
Fraga
Raffael
R
Heart Institute InCor, University of São Paulo, Medical School, São Paulo, Brazil.
Franco
Fábio G
FG
Roveda
Fabiana
F
de Matos
Luciana N J
LN
Braga
Ana M F W
AM
Rondon
Maria U P B
MU
Rotta
Daniel R
DR
Brum
Patricia C
PC
Barretto
Antonio C P
AC
Middlekauff
Holly R
HR
Negrão
Carlos E
CE
D000317:Adrenergic alpha-Antagonists / Q000627:therapeutic use*; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002227:Carbazoles / Q000627:therapeutic use*; D000077261:Carvedilol; D015444:Exercise / Q000502:physiology*; D005260:Female; D005542:Forearm / Q000098:blood supply; D006333:Heart Failure / Q000188:drug therapy / Q000503:physiopathology*; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000098:blood supply / Q000294:innervation; D011412:Propanolamines / Q000627:therapeutic use*; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000503:physiopathology*; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology; D014665:Vasodilator Agents / Q000627:therapeutic use*
D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D002227:Carbazoles; D011412:Propanolamines; D014665:Vasodilator Agents; D000077261:Carvedilol