title: Increased muscle sympathetic nerve activity predicts mortality in heart failure patients.
abstract: BACKGROUND
  Previous studies have associated neurohumoral excitation, as estimated by plasma norepinephrine levels, with increased mortality in heart failure. However, the prognostic value of neurovascular interplay in heart failure (HF) is unknown. We tested the hypothesis that the muscle sympathetic nerve activity (MSNA) and forearm blood flow would predict mortality in chronic heart failure patients.
  
  
  METHODS
  One hundred and twenty two heart failure patients, NYHA II-IV, age 50+/-1 ys, LVEF 33+/-1%, and LVDD 7.1+/-0.2 mm, were followed up for one year. MSNA was directly measured from the peroneal nerve by microneurography. Forearm blood flow was obtained by venous occlusion plethysmography. The variables were analyzed by using univariate, stepwise multivariate Cox proportional hazards analysis, and Kaplan-Meier analysis.
  
  
  RESULTS
  After one year, 34 pts died from cardiac death. The univariate analysis showed that MSNA, forearm blood flow, LVDD, LVEF, and heart rate were significant predictors of mortality. The multivariate analysis showed that only MSNA (P=0.001) and forearm blood flow (P=0.003) were significant independent predictors of mortality. On the basis of median levels of MSNA, survival rate was significantly lower in pts with >49 bursts/min. Similarly, survival rate was significantly lower in pts with forearm blood flow <1.87 ml/min/100 ml (P=0.002).
  
  
  CONCLUSIONS
  MSNA and forearm blood flow predict mortality rate in patients with heart failure. It remains unknown whether therapies that specifically target these abnormalities will improve survival in heart failure.
authors.affiliation: Heart Institute (InCor), University of São Paulo, Medical School, São Paulo, Brazil.
authors.forename: Antonio C P
authors.initials: AC
authors.lastname: Barretto
authors.forename: Amilton C
authors.initials: AC
authors.lastname: Santos
authors.forename: Robinson
authors.initials: R
authors.lastname: Munhoz
authors.forename: Maria U P B
authors.initials: MU
authors.lastname: Rondon
authors.forename: Fábio G
authors.initials: FG
authors.lastname: Franco
authors.forename: Ivani C
authors.initials: IC
authors.lastname: Trombetta
authors.forename: Fabiana
authors.initials: F
authors.lastname: Roveda
authors.forename: Luciana N J
authors.initials: LN
authors.lastname: de Matos
authors.forename: Ana M W
authors.initials: AM
authors.lastname: Braga
authors.forename: Holly R
authors.initials: HR
authors.lastname: Middlekauff
authors.forename: Carlos E
authors.initials: CE
authors.lastname: Negrão
mesh_terms: D005260:Female; D005542:Forearm / Q000098:blood supply / Q000503:physiopathology; D006333:Heart Failure / Q000401:mortality* / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015996:Survival Rate / Q000639:trends; D017779:Sympathetic Fibers, Postganglionic / Q000503:physiopathology*; D013564:Sympathetic Nervous System / Q000503:physiopathology