title: The prognostic value of ventilatory efficiency with beta-blocker therapy in heart failure.
abstract: OBJECTIVE
  Beta-blockade (BB) has been shown to improve outcomes among patients with heart failure (HF). The impact this pharmacological approach has on the prognostic information gained from cardiopulmonary exercise testing (CPX) is, however, unclear.
  
  
  METHODS
  Four hundred seventeen subjects diagnosed with HF underwent CPX. The numbers of subjects prescribed and not prescribed a BB agent were 167 and 250, respectively. Subjects were tracked for cardiac-related mortality after CPX.
  
  
  RESULTS
  Values are reported for the no-BB versus the BB group throughout. Age (57.9 +/- 13.3 vs 55.6 +/- 12.5), peak VO2 (16.2 +/- 5.7 vs 16.5 +/- 5.5 mL x kg(-1) x min(-1)), VE/VCO2 slope (34.2 +/- 9.0 vs 33.2 +/- 7.4), and peak RER (1.07 +/- 0.16 vs 1.05 +/- 0.14) were similar between groups (P > 0.05). Multivariate Cox regression analysis revealed that the VE/VCO2 slope was the superior predictor of death in both groups (chi-square: 71.9, P < 0.001; and 18.4, P < 0.001). The optimal threshold values for VE/VCO2 slope in the no-BB and BB groups were 36.0 and 34.3, respectively.
  
  
  CONCLUSIONS
  The results of the present study indicate that BB does not alter the prognostic value/characteristics of the VE/VCO2 slope. Findings from previous investigations examining the prognostic significance of CPX predominantly using HF groups not receiving a BB agent may, therefore, still be applicable in modern-day clinical practice.
authors.affiliation: Department of Physical Therapy, Virginia Commonwealth University, Richmond, VA 23298-0224, USA. raarena@.vcu.edu
authors.forename: Ross A
authors.initials: RA
authors.lastname: Arena
authors.forename: Marco
authors.initials: M
authors.lastname: Guazzi
authors.forename: Jonathan
authors.initials: J
authors.lastname: Myers
authors.forename: Joshua
authors.initials: J
authors.lastname: Abella
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology* / Q000627:therapeutic use; D005080:Exercise Test; D045853:Exhalation; D005260:Female; D006333:Heart Failure / Q000188:drug therapy* / Q000401:mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D011379:Prognosis; D011446:Prospective Studies; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left
chemical_list: D000319:Adrenergic beta-Antagonists