title: Work-rate affects cardiopulmonary exercise test results in heart failure.
abstract: OBJECTIVE
  Cardiopulmonary exercise test (CPET) is used to evaluate patients with chronic heart failure (HF) usually by means of a personalized ramp exercise protocol. Our aim was to evaluate if exercise duration or ramp rate influences the results.
  
  
  RESULTS
  Ninety HF patients were studied (peak V (O(2)): >20 ml/min/kg, n=28, 15-20 ml/min/kg, n=39 and <15 ml/min/kg, n=23). Each patient did four CPET studies. The initial study was used to separate the subjects into three groups, according to their exercise capacity. In the remaining studies, work-rate was increased at three different rates designed to have the subjects reach peak exercise in 5, 10 and 15 min from the start of the ramp increase in work-rate, respectively. The order was randomized. The work-rate applied for the total population averaged 22.7+/-8.0, 11.6+/-3.7, 7.5+/-2.9 W/min with effective loaded exercise duration of 5 min and 16 s+/-29 s, 9 min and 43 s+/-49 s and 14 min and 32 s+/-1 min and 12 s for the 5-, 10- and 15-min tests, respectively. Peak V (O(2)) averaged 16.9+/-4.3*, 18.0+/-4.4 and 18.0+/-5.4 ml/min/kg for the 5-, 10- and 15-min tests, (*=p<0.001 vs. 10 min). The shortest test had the lowest peak heart rate and ventilation and highest peak work-rate. Peak V (O(2)) and heart rate were lowest in 5-min tests regardless of HF severity. The DeltaV (O(2))/Deltawork-rate was lowest in 5-min tests and highest in 15-min tests. At all ramp rates, DeltaV (O(2))/Deltawork-rate was lower for the subjects with the lower peak V (O(2)). The V (e)/V (CO(2)) slope and V (O(2)) at anaerobic threshold were not affected by the protocol for any grade of HF.
  
  
  CONCLUSIONS
  In chronic HF, exercise protocol has a small effect on peak V (O(2)) and DeltaV (O(2))/Deltawork but does not affect V (O(2)) at anaerobic threshold and V (e)/V (CO(2)) slope.
authors.affiliation: Centro Cardiologico Monzino IRCCS, Institute of Cardiology, University of Milan, 20138 Milan, Italy. Piergiuseppe.Agostoni@ccfm.it
authors.forename: Piergiuseppe
authors.initials: P
authors.lastname: Agostoni
authors.forename: Michele
authors.initials: M
authors.lastname: Bianchi
authors.forename: Andrea
authors.initials: A
authors.lastname: Moraschi
authors.forename: Pietro
authors.initials: P
authors.lastname: Palermo
authors.forename: Gaia
authors.initials: G
authors.lastname: Cattadori
authors.forename: Rocco
authors.initials: R
authors.lastname: La Gioia
authors.forename: Maurizio
authors.initials: M
authors.lastname: Bussotti
authors.forename: Karlman
authors.initials: K
authors.lastname: Wasserman
mesh_terms: D015308:Anaerobic Threshold; D005080:Exercise Test; D005260:Female; D006333:Heart Failure / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption