title: Do metoprolol and carvedilol have equivalent effects on diurnal heart rate in patients with chronic heart failure?
abstract: BACKGROUND
  Carvedilol exerted a greater reduction in mortality than metoprolol tartrate in the Carvedilol or Metoprolol European Trial (COMET). However, it is unclear if the degree and time course of beta1-blockade during a 24-h period was similar with each agent at the doses used. Therefore we analyzed 24-h ECG Holter recordings from a study which compared the long-term clinical efficacy of metoprolol tartrate to carvedilol in chronic heart failure patients using the same dosing regimen as in COMET.
  
  
  RESULTS
  Fifty-one patients with chronic heart failure with a mean LVEF 26+/-1.8% were randomized in a double-blind fashion to receive metoprolol tartrate 50 mg bid or carvedilol 25 mg bid. 24-h ECG monitoring (Holter) was performed at baseline, 12 weeks and 1 year. Adequate quality recordings for analysis were obtained from 43 subjects at baseline, 42 at 12 weeks and 29 subjects at 1 year. Both drugs produced a fall in average 24-h heart rate from baseline at 12 weeks and at 1 year: metoprolol 88+/-3 to 71+/-2 and 69+/-3 bpm; carvedilol 83+/-3 to 70+/-2 and 70+/-3 bpm respectively (all p<0.001). The pattern of suppression of heart rate during the 24-h period was similar for both drugs.
  
  
  CONCLUSIONS
  Metoprolol tartrate 50 mg bid and carvedilol 25 mg bid had similar effects on 24-h heart rate. This result suggests that the degree of beta1-blockade produced by these two drugs in these doses is comparable and the superior survival effect of carvedilol compared to metoprolol seen in COMET is likely to be due to actions of carvedilol other than beta1-blockade.
authors.affiliation: Division of Cardiology, Department of Medicine and Therapeutics, The Chinese University of Hong Kong, 9th Fl Clinical Science Bldg, Prince of Wales Hospital, Hong Kong SAR.
authors.forename: John E
authors.initials: JE
authors.lastname: Sanderson
authors.forename: Leata Y C
authors.initials: LY
authors.lastname: Leung
authors.forename: Skiva K W
authors.initials: SK
authors.lastname: Chan
authors.forename: Gabriel W K
authors.initials: GW
authors.lastname: Yip
authors.forename: Jeffrey W H
authors.initials: JW
authors.lastname: Fung
authors.forename: C M
authors.initials: CM
authors.lastname: Yu
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D002227:Carbazoles / Q000008:administration & dosage / Q000494:pharmacology*; D000077261:Carvedilol; D015716:Electrocardiography, Ambulatory; D006333:Heart Failure / Q000188:drug therapy* / Q000401:mortality / Q000503:physiopathology; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008790:Metoprolol / Q000008:administration & dosage / Q000494:pharmacology*; D011412:Propanolamines / Q000008:administration & dosage / Q000494:pharmacology*; D016032:Randomized Controlled Trials as Topic; D013318:Stroke Volume
chemical_list: D000319:Adrenergic beta-Antagonists; D002227:Carbazoles; D011412:Propanolamines; D000077261:Carvedilol; D008790:Metoprolol