title: Heart failure: comparison between six-minute walk test and cardiopulmonary test.
abstract: BACKGROUND
  Chronic heart failure (HF) is a syndrome characterized by reduced cardiac output in relation to the metabolic needs of the organism, as well as metabolic and neurohormonal axis abnormalities. Symptoms such as fatigue and dyspnoea are notorious and stress tests are widely used to assess functional capacity, prognosis and effectiveness of therapeutic interventions in this syndrome.
  
  
  OBJECTIVE
  To evaluate the reproducibility of the six-minute walk test (6MW) in patients with HF and correlate the magnitude of the variables reached at peak exercise of the 6MWT with a cardiopulmonary exercise test (CPET).
  
  
  METHODS
  We studied 16 patients (12 men and 4 women) diagnosed with HF FC I-II (NYHA). The volunteers underwent two 6MWT (6MWT'1 and 6MWT'2) with 30-minute interval between them; then, they underwent a maximum CPET.
  
  
  RESULTS
  All variables obtained in the two 6MWT' proved to be significant with high correlations: distance walked (DW) (r = 0.93, p < 0.0001), heart rate (HR) (r = 0.89, p < 0.0001), oxygen consumption (VO2) (r = 0.93, p < 0.0001) and scale of perceived exertion (r = 0.85, p < 0.0001). In turn, all variables analyzed in the 6MWT' showed significant and moderate correlations with the variables obtained from the CPET, namely: peak HR (r = 0.66; p = 0.005); VO2 (r = 0.57; p = 0.02) and VO2 in the CPET and DT in the 6MWT'2 (r = 0.70; p = 0.002).
  
  
  CONCLUSIONS
  The 6MWT was reproducible in this group of patients with HF (NYHA - I-II) and correlated with the CPET. Therefore, it is a tool for reliable evaluation, and a suitable, safe and low-cost alternative for the prescription of aerobic exercise in patients with HF.
authors.affiliation: Departamento de Clínica Médica Laboratório de Fisiologia do Exercício, Divisão de Cardiologia, Faculdade de Medicina de Ribeirão Preto, USP, Brazil. carvalhoeev@usp.br
authors.forename: Eduardo Elias Vieira de
authors.initials: EE
authors.lastname: Carvalho
authors.forename: Daniela Caetano
authors.initials: DC
authors.lastname: Costa
authors.forename: Júlio César
authors.initials: JC
authors.lastname: Crescêncio
authors.forename: Giovani Luiz De
authors.initials: GL
authors.lastname: Santi
authors.forename: Valéria
authors.initials: V
authors.lastname: Papa
authors.forename: Fabiana
authors.initials: F
authors.lastname: Marques
authors.forename: André
authors.initials: A
authors.lastname: Schmidt
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Marin-Neto
authors.forename: Marcus Vinícius
authors.initials: MV
authors.lastname: Simões
authors.forename: Lourenço
authors.initials: L
authors.lastname: Gallo Junior
mesh_terms: D000368:Aged; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D006333:Heart Failure / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012129:Respiratory Function Tests; D018709:Statistics, Nonparametric; D013997:Time Factors; D016138:Walking / Q000502:physiology