title: [Study on six-minute walk test and cardiac output response against exercise in patients with chronic heart failure].
abstract: OBJECTIVE
  To evaluate the significance of cardiac output (CO) response against exercise determined by IGR method and LVEF, 6 MWT distance in patients with chronic heart failure (CHF).
  
  
  METHODS
  To adopt 6 MWT, and before and after the test measuring the CO by the IGR method, furthermore, measure LVEF to 36 patients (heart failure group) with CHF, compare with the health groups (control group).
  
  
  RESULTS
  The 6MWT distance of heart failure group (333.00 +/- 49.64) m decrease compared with the control group (582.56 +/- 67.97) m (P < 0.01), moreover, the distance of NYHA class III (314.82 +/- 36.27) m is significantly shorter than II (361.57 +/- 55.42) m (P < 0.05). The LVEF of heart failure group (47.0 +/- 0.4)% reduce compared with the control group (66.9 +/- 5.2)% (P < 0.01), and the data of NYHA class III (43.3 +/- 10.3)% is significantly lower than II (52.8 +/- 7.6)% (P < 0.01). The increase in CO response against exercise of heart failure group (5.97 +/- 1.89) L/min decrease compared with control group (8.88 +/- 0.52) L/min (P < 0.01), furthermore, the value of NYHA class III (5.31 +/- 1.52) L/min, compared with II (7.01 +/- 1.98)L/min, is obviously lower (P < 0.01). The 6MWT distance correlates positively with the increase in CO response against exercise (r = 0.63, P < 0.01), but the correlation is not found between the increase CO response against exercise and the LVEF (r = 0.11, P > 0.05).
  
  
  CONCLUSIONS
  Our results show that CO response against exercise measured by IGR method, with the advantages of being noninvasive, safe, convenient and accurate, combining with the 6MWT can evaluate cardiac reserve in patient with CHF.
authors.affiliation: Department of Cardiology, Daping Hospital, Third Millitary Medical University, Chongqing 400042, China.
authors.forename: Su-Ping
authors.initials: SP
authors.lastname: Zhou
authors.forename: Cheng-Ming
authors.initials: CM
authors.lastname: Yang
authors.forename: Wei-Bin
authors.initials: WB
authors.lastname: Shi
authors.forename: Xu-Kai
authors.initials: XK
authors.lastname: Wang
authors.forename: Chun-Yu
authors.initials: CY
authors.lastname: Zeng
mesh_terms: D000328:Adult; D000368:Aged; D002302:Cardiac Output; D016022:Case-Control Studies; D002908:Chronic Disease; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016138:Walking