title: Heart rate achieved or beta-blocker dose in patients with chronic heart failure: which is the better target?
abstract: OBJECTIVE
  To investigate whether the mortality of patients with chronic heart failure (CHF) due to left ventricular systolic dysfunction (LVSD) is more strongly related to beta-blocker dose or to heart rate. It is known that beta-blockers reduce mortality in patients with CHF and LVSD, but the primary mechanism of action is uncertain.
  
  
  RESULTS
  Patients with an ejection fraction ≤40%, who were in sinus rhythm both at an initial (visit 1) and at a 4-month clinic review (visit 2), were followed for a maximum of 36 months. The relationships between heart rate, beta-blocker dose, and survival in a multivariable model were examined. Of 654 eligible patients, 381 (58%) were started on beta-blockers prior to the initial visit, increasing to 537 (82%) by visit 2. During follow-up, 142 (22%) patients died. Neither resting heart rate nor beta-blocker dose at visit 1 predicted mortality (P = 0.09 and P = 0.99), but resting heart rate at visit 2 did (P = 0.02). Beta-blocker use at visit 2 was associated with better outcome (P = 0.03) but with little variation in outcome according to dose. Patients with a heart rate of 58-64 b.p.m. at visit 2 had the best prognosis.
  
  
  CONCLUSIONS
  The use of beta-blockers and resting heart rate at visit 2 both independently indicated prognosis, but beta-blocker dose did not. Beta-blockers may reduce mortality by several mechanisms; one that may be specific to blockade of adrenergic receptors and another related to heart rate reduction. Achieving a target heart rate range may be an appropriate therapeutic goal for patients with CHF.
authors.affiliation: Department of Cardiology, Post graduate Medical Institute (Hull York Medical School), University of Hull, UK.
authors.forename: Damien
authors.initials: D
authors.lastname: Cullington
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Goode
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Clark
authors.forename: John G F
authors.initials: JG
authors.lastname: Cleland
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage* / Q000627:therapeutic use; D000368:Aged; D000959:Antihypertensive Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D016001:Confidence Intervals; D005260:Female; D006333:Heart Failure / Q000188:drug therapy* / Q000473:pathology; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011336:Probability; D011379:Prognosis; D016016:Proportional Hazards Models; D012146:Rest / Q000502:physiology*; D013223:Statistics as Topic; D013318:Stroke Volume; D016277:Ventricular Function, Left
chemical_list: D000319:Adrenergic beta-Antagonists; D000959:Antihypertensive Agents