title: Predicting maximal HR in heart failure patients on β-blockade therapy.
abstract: OBJECTIVE
  Standards for estimating maximal HR are important when interpreting the adequacy of physiologic stress during exercise testing, assessing chronotropic response, and prescribing an exercise training regimen. The equation 220 - age is used to estimate maximum HR; however, it overestimates measured maximal HR in patients taking β-adrenergic blockade (βB) therapy. This study developed and validated a practical equation to predict maximal HR in patients with heart failure (HF) taking βB therapy.
  
  
  METHODS
  Data from symptom-limited exercise tests completed on patients with systolic HF participating in the Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training trial and taking a βB agent were used to develop a simplified equation, which was validated using bootstrapping.
  
  
  RESULTS
  The simplified derived equation was 119 + 0.5 (resting HR) - 0.5 (age) - (0, if test was completed using a treadmill; 5, if using a stationary bike). The R2 and SEE were 0.28 and 18 beats·min(-1), respectively. Validation of this equation yielded a mean R and SEE of 0.28 and 18 beats·min(-1), respectively. For the equation 220 - age, the R2 was -2.93, and the SEE was 43 beats·min(-1).
  
  
  CONCLUSIONS
  We report a valid and simple population-specific equation for estimating peak HR in patients with HF taking βB therapy. This equation should be helpful when evaluating chronotropic response or assessing if a maximum effort was provided during exercise testing. We caution, however, that the magnitude of the variation (SEE = 18 beats·min(-1)) associated with this prediction equation may make it impractical when prescribing exercise intensity.
authors: Department of Internal Medicine, Henry Ford Hospital, Detroit, MI, USA. sketeyi1@hfhs.org
authors: Steven J
authors: SJ
authors: Keteyian
authors: Dalane
authors: D
authors: Kitzman
authors: Faiez
authors: F
authors: Zannad
authors: Joel
authors: J
authors: Landzberg
authors: J Malcolm
authors: JM
authors: Arnold
authors: Peter
authors: P
authors: Brubaker
authors: Clinton A
authors: CA
authors: Brawner
authors: Daniel
authors: D
authors: Bensimhon
authors: Anne S
authors: AS
authors: Hellkamp
authors: Greg
authors: G
authors: Ewald
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology / Q000627:therapeutic use*; D000367:Age Factors; D000368:Aged; D005080:Exercise Test; D005260:Female; D006333:Heart Failure / Q000188:drug therapy* / Q000503:physiopathology*; D006339:Heart Rate / Q000187:drug effects* / Q000502:physiology*; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests
chemical_list: D000319:Adrenergic beta-Antagonists