What is the clinical evidence from this study?

Study design: Cohort. Population: Asymptomatic (n=5437). Intervention: Exercise stress testing (heart rate response). Primary outcome: Mortality (3% risk reduction per 1-bpm increase in peak HR, p=<0.001).

What does this research mean for the field?

In asymptomatic women, the risk of death is reduced by 3% for every 1-beat-per-minute increase in peak heart rate and by 2% for every 1-beat-per-minute increase in heart rate reserve, demonstrating that traditional male-based calculations overestimate maximum heart rate for age in women. Novelty: ClaimNovelty.CONTRADICTORY. Consensus alignment: ConsensusAlignment.CHALLENGES_CONSENSUS.

June 29, 2010Open Access

Heart Rate Response to Exercise Stress Testing in Asymptomatic Women

Q: What are the key findings of this study?

In asymptomatic women, the risk of death was reduced by 3% for every 1-beat-per-minute increase in peak heart rate and by 2% for every 1-beat-per-minute increase in heart rate reserve (P<0.001).

Q: What does this research mean for the field?

In asymptomatic women, the risk of death is reduced by 3% for every 1-beat-per-minute increase in peak heart rate and by 2% for every 1-beat-per-minute increase in heart rate reserve, demonstrating that traditional male-based calculations overestimate maximum heart rate for age in women. Novelty: ClaimNovelty.CONTRADICTORY. Consensus alignment: ConsensusAlignment.CHALLENGES_CONSENSUS.

Key Result

In asymptomatic women, the risk of death was reduced by 3% for every 1-beat-per-minute increase in peak heart rate and by 2% for every 1-beat-per-minute increase in heart rate reserve (P<0.001).

Study Design

Type

Cohort (n=5,437)

Structured PICO

Does heart rate response to exercise stress testing predict mortality in asymptomatic women?

Population

5,437 asymptomatic women, mean age 52+/-11 years

Intervention

Symptom-limited maximal exercise stress test

Outcome

Death (all-cause mortality) over 15.9+/-2.2 yearshard clinical

Chronotropic incompetence is an independent predictor of mortality in asymptomatic women, but traditional male-based calculations overestimate maximum HR for age in women, highlighting the need for sex-specific parameters.

Main Result

Effect estimate: 3% risk reduction per 1-bpm increase in peak HR

p-value: p=<0.001

Abstract

BACKGROUND: The definition of a normal heart rate (HR) response to exercise stress testing in women is poorly understood, given that most studies describing a normative response were predominately based on male data. Measures of an attenuated HR response (chronotropic incompetence) and age-predicted HR have not been validated in asymptomatic women. We investigated the association between HR response to exercise testing and age with prognosis in 5437 asymptomatic women. METHODS AND RESULTS: Participants underwent a symptom-limited maximal stress test in 1992. HR reserve (change in HR from rest to peak), chronotropic index, and age-predicted peak HR were calculated. Deaths were identified to December 31, 2008. Mean age at baseline was 52+/-11 years, with 549 deaths (10%) over 15.9+/-2.2 years. Mean peak HR was inversely associated with age; mean peak HR=206-0.88(age). After adjusting for exercise capacity and traditional cardiac risk factors, risk of death was reduced by 3% for every 1-beat-per-minute increase in peak HR, and by 2% for every 1-beat-per-minute increase in HR reserve (P/=1 SD below the mean predicted HR or a chronotropic index <0.80 based on the prediction model established by this cohort were independent predictors of mortality (P<0.001 and P=0.023, respectively). CONCLUSIONS: Chronotropic incompetence is associated with an increased risk of death in asymptomatic women; however, the traditional male-based calculation overestimates the maximum HR for age in women. Sex-specific parameters of physiological HR response to exercise should be incorporated into clinical practice.