Impaired chronotropic response to exercise stress testing as a predictor of mortality. Academic Article uri icon

Overview

abstract

  • CONTEXT: Chronotropic incompetence, an attenuated heart rate response to exercise, is a predictor of all-cause mortality in healthy populations. This association may be independent of exercise-induced myocardial perfusion defects. OBJECTIVE: To examine the prognostic significance of chronotropic incompetence in a low-risk cohort of patients referred for treadmill stress testing with thallium imaging. DESIGN: Prospective cohort study conducted between September 1990 and December 1993. SETTING: Tertiary care academic medical center. PATIENTS: Consecutive patients (1877 men and 1076 women; mean age, 58 years) who were not taking beta-blockers and who were referred for symptom-limited treadmill thallium testing. MAIN OUTCOME MEASURES: Association of chronotropic incompetence, defined as either failure to achieve 85% of the age-predicted maximum heart rate or a low chronotropic index, a heart rate response measure that accounts for effects of age, resting heart rate, and physical fitness, with all-cause mortality during 2 years of follow-up. RESULTS: Three hundred sixteen patients (11%) failed to reach 85% of the age-adjusted maximum heart rate, 762 (26%) had a low chronotropic index, and 612 (21%) had thallium perfusion defects. Ninety-one patients died during the follow-up period. After adjustment for age, sex, thallium perfusion defects, and other confounders, failure to reach 85% of the age-predicted maximum heart rate was associated with increased risk of death (adjusted relative risk [RR], 1.84; 95% confidence interval [CI], 1.13-3.00; P=.01), as was a low chronotropic index (adjusted RR, 2.19; 95% CI, 1.43-3.44; P<.001). CONCLUSION: Among patients with known or suspected coronary disease, chronotropic incompetence is independently predictive of all-cause mortality, even after considering thallium perfusion defects. Incorporation of chronotropic response into the routine interpretation of stress thallium studies may improve the prognostic power of this test.

publication date

  • February 10, 1999

Research

keywords

  • Cardiovascular Diseases
  • Exercise Test
  • Heart Rate
  • Myocardial Ischemia

Identity

Scopus Document Identifier

  • 0033540644

Digital Object Identifier (DOI)

  • 10.1001/jama.281.6.524

PubMed ID

  • 10022108

Additional Document Info

volume

  • 281

issue

  • 6