Effects of beta-blockers on ventilation efficiency in heart failure.
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).
Agostoni
Piergiuseppe
P
Centro Cardiologico Monzino, IRCCS, Department of Cardiovascular Sciences, University of Milan, Milan, Italy. piergiuseppe.agostoni@unimi.it
Apostolo
Anna
A
Cattadori
Gaia
G
Salvioni
Elisabetta
E
Berna
Giovanni
G
Antonioli
Laura
L
Vignati
Carlo
C
Schina
Mauro
M
Sciomer
Susanna
S
Bussotti
Maurizio
M
Palermo
Pietro
P
Fiorentini
Cesare
C
Contini
Mauro
M
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
D000319:Adrenergic beta-Antagonists; D002227:Carbazoles; D011412:Propanolamines; D000077261:Carvedilol; D017298:Bisoprolol