title: Effects of beta-blockers on ventilation efficiency in heart failure.
abstract: BACKGROUND
  Hyperventilation and consequent reduction of ventilation (VE) efficiency are frequently observed during exercise in heart failure (HF) patients, resulting in an increased slope of VE/carbon dioxide (VE/Vco(2)) relationship. The latter is an independent predictor of HF prognosis. beta-Blockers improve the prognosis of HF patients. We evaluated the effect on the efficiency of VE of a beta(1)-beta(2) unselective (carvedilol) versus a beta(1) selective (bisoprolol) beta-blocker.
  
  
  METHODS
  We analyzed consecutive maximal cardiopulmonary exercise tests performed on 572 clinically stable HF patients (New York Heart Association class I-III, left ventricle ejection fraction < or =50%) categorized in 3 groups: 81 were not treated with beta-blocker, 304 were treated with carvedilol, and 187 were treated with bisoprolol. Clinical conditions were similar.
  
  
  RESULTS
  The VE/Vco(2) slope was lower in carvedilol- compared with bisoprolol-treated patients (29.7 +/- 0.4 vs 31.6 +/- 0.5, P = .023, peak oxygen consumption adjusted) and with patients not receiving beta-blockers (31.6 +/- 0.7, P = .036). Maximum end-tidal CO(2) pressure during the isocapnic buffering period was higher in patients treated with carvedilol (39.0 +/- 0.3 mm Hg) than with bisoprolol (37.2 +/- 0.4 mm Hg, P < .001) and in patients not receiving beta-blockers (37.2 +/- 0.5 mm Hg, P = .001).
  
  
  CONCLUSIONS
  Reduction of hyperventilation, with improvement of VE efficiency during exercise (reduction of VE/Vco(2) slope and increase of maximum end-tidal CO(2) pressure), is specific to carvedilol (beta(1)-beta(2) unselective blocker) and not to bisoprolol (beta(1)-selective blocker).
authors.affiliation: Centro Cardiologico Monzino, IRCCS, Department of Cardiovascular Sciences, University of Milan, Milan, Italy. piergiuseppe.agostoni@unimi.it
authors.forename: Piergiuseppe
authors.initials: P
authors.lastname: Agostoni
authors.forename: Anna
authors.initials: A
authors.lastname: Apostolo
authors.forename: Gaia
authors.initials: G
authors.lastname: Cattadori
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Salvioni
authors.forename: Giovanni
authors.initials: G
authors.lastname: Berna
authors.forename: Laura
authors.initials: L
authors.lastname: Antonioli
authors.forename: Carlo
authors.initials: C
authors.lastname: Vignati
authors.forename: Mauro
authors.initials: M
authors.lastname: Schina
authors.forename: Susanna
authors.initials: S
authors.lastname: Sciomer
authors.forename: Maurizio
authors.initials: M
authors.lastname: Bussotti
authors.forename: Pietro
authors.initials: P
authors.lastname: Palermo
authors.forename: Cesare
authors.initials: C
authors.lastname: Fiorentini
authors.forename: Mauro
authors.initials: M
authors.lastname: Contini
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage / Q000627:therapeutic use*; D017298:Bisoprolol / Q000008:administration & dosage / Q000627:therapeutic use*; D002227:Carbazoles / Q000008:administration & dosage / Q000627:therapeutic use*; D000077261:Carvedilol; D004452:Echocardiography; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000187:drug effects; D011379:Prognosis; D011412:Propanolamines / Q000008:administration & dosage / Q000627:therapeutic use*; D012123:Pulmonary Ventilation / Q000187:drug effects*; D012189:Retrospective Studies; D013318:Stroke Volume / Q000187:drug effects; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000187:drug effects
chemical_list: D000319:Adrenergic beta-Antagonists; D002227:Carbazoles; D011412:Propanolamines; D000077261:Carvedilol; D017298:Bisoprolol