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Effects of β-Blockers on Maximal Heart Rate Prediction Equations in a Cardiac Population

Elizabeth Godlasky1, Trisha Hoffman, Sonya Weber-Peters

  • 1The Penn State University Milton S. Hershey Medical Center, Heart and Vascular Institute, Hershey, Pennsylvania (Mss Godlasky, Hoffman, and Weber-Peters, Messrs Bradford and Miller, and Dr Lott); and Public Health Sciences, Penn State University Hershey, Pennsylvania (Mr Kunselman).

Journal of Cardiopulmonary Rehabilitation and Prevention
|February 22, 2018
PubMed

Insights

New maximal heart rate (HRmax) prediction equations for coronary artery disease (CAD) patients on beta-blocker (BB) therapy were derived. Patients holding BB therapy can use standard equations, but those taking BBs require specific HRmax formulas.

Area of Science:

  • Cardiology
  • Exercise Physiology
  • Pharmacology

Background:

  • Maximal heart rate (HRmax) prediction is crucial for exercise prescription and stress testing in patients with coronary artery disease (CAD).
  • Existing HRmax equations may not accurately reflect physiological responses in CAD patients, particularly those on beta-blocker (BB) therapy.
  • Understanding the impact of BBs on HRmax is essential for safe and effective exercise management in this population.

Purpose of the Study:

  • To develop specific HRmax prediction equations for CAD patients undergoing exercise testing, stratified by BB therapy status.
  • To compare the accuracy of newly derived equations against established HRmax prediction formulas (e.g., Fox, Brawner).
  • To assess the influence of BB therapy timing (held vs. continued) on achieved HRmax during exercise testing.

Main Methods:

  • Retrospective analysis of stress echocardiogram treadmill tests in patients diagnosed with CAD.
  • Patients were categorized into three groups: no BB therapy, BB therapy held 12-24 hours prior, and BB therapy continued on test day.
  • HRmax prediction equations were derived for each group, and their accuracy was compared to existing formulas using mean bias analysis.

Main Results:

  • Specific HRmax equations were derived: no BB = 200 - 0.79 × age; held BB = 193 - 0.71 × age; took BB = 168 - 0.51 × age.
  • Achieved HRmax was not significantly different between the no BB and held BB groups.
  • The 'took BB' group exhibited significantly lower HRmax. Existing equations (Fox, Brawner) showed significant over- or underestimation of achieved HRmax in different patient groups.

Conclusions:

  • For CAD patients holding BB therapy on the test day, HRmax estimation equations used for patients never on BBs are applicable.
  • The Brawner (no BB) equation demonstrated comparable performance to equations derived for CAD patients holding BBs.
  • Further research is warranted to optimize the timing of BB administration in relation to exercise testing for accurate HRmax assessment.
Abstract

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