title: Age-related maximum heart rate among ischemic and nonischemic heart failure patients receiving β-blockade therapy.
abstract: BACKGROUND
  Equations to predict maximum heart rate (HR(max)) in heart failure (HF) patients receiving β-adrenergic blocking (BB) agents do not consider the cause of HF. We determined equations to predict HR(max) in patients with ischemic and nonischemic HF receiving BB therapy.
  
  
  RESULTS
  Using treadmill cardiopulmonary exercise testing, we studied HF patients receiving BB therapy being considered for transplantation from 1999 to 2010. Exclusions were pacemaker and/or implantable defibrillator, left ventricle ejection fraction (LVEF) >50%, peak respiratory exchange ratio (RER) <1.00, and Chagas disease. We used linear regression equations to predict HR(max) based on age in ischemic and nonischemic patients. We analyzed 278 patients, aged 47 ± 10 years, with ischemic (n = 75) and nonischemic (n = 203) HF. LVEF was 30.8 ± 9.4% and 28.6 ± 8.2% (P = .04), peak VO(2) 16.9 ± 4.7 and 16.9 ± 5.2 mL kg(-1) min(-1) (P = NS), and the HR(max) 130.8 ± 23.3 and 125.3 ± 25.3 beats/min (P = .051) in ischemic and nonischemic patients, respectively. We devised the equation HR(max) = 168 - 0.76 × age (R(2) = 0.095; P = .007) for ischemic HF patients, but there was no significant relationship between age and HR(max) in nonischemic HF patients (R(2) = 0.006; P = NS).
  
  
  CONCLUSIONS
  Our study suggests that equations to estimate HR(max) should consider the cause of HF.
authors.affiliation: Heart Institute, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil. miguelmorita@me.com
authors.forename: Miguel Morita
authors.initials: MM
authors.lastname: Fernandes Silva
authors.forename: Fernando
authors.initials: F
authors.lastname: Bacal
authors.forename: Jean Marcelo
authors.initials: JM
authors.lastname: Roque
authors.forename: Iram Soares
authors.initials: IS
authors.lastname: Teixeira-Neto
authors.forename: Nelson
authors.initials: N
authors.lastname: Carvas Junior
authors.forename: Edimar Alcides
authors.initials: EA
authors.lastname: Bocchi
authors.forename: Guilherme Veiga
authors.initials: GV
authors.lastname: Guimarães
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology / Q000627:therapeutic use*; D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000187:drug effects / Q000502:physiology*; D005080:Exercise Test / Q000379:methods / Q000592:standards*; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000188:drug therapy / Q000503:physiopathology*; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000150:complications / Q000188:drug therapy / Q000503:physiopathology*; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D000319:Adrenergic beta-Antagonists