title: Comparison of the effects of carvedilol and metoprolol on exercise ventilatory efficiency in patients with congestive heart failure.
abstract: BACKGROUND
  The slope of the relationship between ventilation and carbon dioxide production (VE/VCO2 slope), obtained during symptom-limited ramp exercise testing, reflects exercise ventilatory efficiency. Importantly, the VE/VCO2 slope is related to prognosis in patients with congestive heart failure (CHF). The aim of the present study was to determine the relationship between the institution of beta-blockers, carvedilol or metoprolol, and the VE/VCO2 slope during exercise in patients with CHF.
  
  
  RESULTS
  Fifty-seven patients with New York Heart Association functional class II or III with a radionuclide left ventricular ejection fraction (LVEF) of less than 40% received carvedilol or metoprolol in a randomized fashion. The VE/VCO2 slope, LVEF and plasma brain natriuretic peptide (BNP) concentration were determined before and after 16 weeks of treatment. LVEF improved (p<0.01), but the VE/VCO2 slope and BNP did not. A significant improvement in the VE/VCO2 slope was observed in patients with LVEF <29% or BNP >63 pg/ml (respective baseline median values) (p<0.05, p<0.05). In patients with BNP >63 pg/ml, the improvement effect on the VE/VCO2 slope with carvedilol was significantly greater than that with metoprolol (p<0.05) and a significant improvement in the VE/VCO2 slope was observed only in those who took carvedilol (p<0.01).
  
  
  CONCLUSIONS
  The VE/VCO2 slope was not improved after beta-blocker therapy in any of the patients. However, it did improve in patients with a lower LVEF or higher BNP level at baseline, and carvedilol was more effective than metoprolol in improving the VE/VCO2 slope in patients with higher BNP levels at baseline.
authors.affiliation: Cardiopulmonary Division, Department of Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Masaharu
authors.initials: M
authors.lastname: Kataoka
authors.forename: Toru
authors.initials: T
authors.lastname: Satoh
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Iwao
authors.initials: I
authors.lastname: Nakamura
authors.forename: Takashi
authors.initials: T
authors.lastname: Kohno
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yoshizawa
authors.forename: Toshihisa
authors.initials: T
authors.lastname: Anzai
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ogawa
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology* / Q000627:therapeutic use; D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D002227:Carbazoles / Q000494:pharmacology* / Q000627:therapeutic use; D002245:Carbon Dioxide / Q000378:metabolism*; D000077261:Carvedilol; D004305:Dose-Response Relationship, Drug; D015444:Exercise / Q000502:physiology*; D005260:Female; D006333:Heart Failure / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008790:Metoprolol / Q000494:pharmacology* / Q000627:therapeutic use; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology; D011379:Prognosis; D011412:Propanolamines / Q000494:pharmacology* / Q000627:therapeutic use; D012123:Pulmonary Ventilation / Q000187:drug effects* / Q000502:physiology; D013318:Stroke Volume / Q000502:physiology
chemical_list: D000319:Adrenergic beta-Antagonists; D002227:Carbazoles; D011412:Propanolamines; D000077261:Carvedilol; D020097:Natriuretic Peptide, Brain; D002245:Carbon Dioxide; D008790:Metoprolol