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Population-based study of heart rate variability and prevalent myocardial infarction. The Atherosclerosis Risk in
D Liao1, G W Evans, L E Chambless
1Department of Epidemiology, School of Public Health, University of North Carolina at Chapel Hill 27514, USA.
Insights
This study found that myocardial infarction (MI) is associated with lower heart rate variability (HRV) in the general population. However, this association disappears when accounting for beta-blocker medication use.
Area of Science:
- Cardiovascular Medicine
- Epidemiology
- Physiology
Background:
- Myocardial infarction (MI) survivors often show reduced heart rate variability (HRV) in clinical settings.
- Population-level data on the association between MI and HRV are limited.
- Heart rate variability (HRV) is a key indicator of autonomic nervous system function.
Purpose of the Study:
- To investigate the relationship between prevalent myocardial infarction (MI) and heart rate variability (HRV) in a general population sample.
- To determine if MI is independently associated with lower HRV.
- To assess the impact of beta-blocker medication on the MI-HRV association.
Main Methods:
- A population-based sample of 2,243 adults aged 45-64 years was analyzed.
- Participants included individuals with and without a history of myocardial infarction (MI).
- Resting heart rate data were analyzed using spectral analysis to quantify high-frequency and low-frequency HRV.
Main Results:
- Individuals with MI exhibited significantly lower high-frequency and low-frequency HRV compared to those without MI.
- Age, race, and sex-adjusted analyses showed a significant association between MI and lower HRV.
- After adjusting for beta-blocker medication, the statistical association between MI and lower HRV was no longer significant.
Conclusions:
- This population-based study supports an inverse association between prevalent myocardial infarction (MI) and heart rate variability (HRV).
- The findings suggest that beta-blocker use may diminish the observed association between MI and impaired HRV.
- Impaired HRV in MI patients may contribute to increased cardiovascular event risk, and beta-blockers might mitigate this effect.
Abstract:
Clinically based studies have indicated that patients who have suffered myocardial infarction (MI) exhibit lower heart rate variability (HRV). Such associations have not been reported at the population level. To investigate whether MI is related to lower HRV in the general population, the authors examined a stratified random sample of 2,243 men and women aged 45-64 years, of whom 260 had had MI and 1,983 were free of any coronary heart disease manifestations. All were part of the biracial cohort of the Atherosclerosis Risk in Communities study sampled from four United States communities. Resting, 2-minute supine heart rate data were analyzed using spectral analysis to estimate high-frequency (0.16-0.35 Hz) and low-frequency (0.025-0.15 Hz) spectral powers as conventional indices of HRV. The mean levels of high-frequency powers were 1.02 and 1.23 (beats/min)2 for MI and non-MI groups, respectively (P < .05), and the low-frequency means were 2.46 and 3.11 (beats/min)2 for MI and non-MI groups, respectively (P < .01). Age, race, and sex-adjusted odds ratios (95% confidence interval) of lower high-frequency and low-frequency powers contrasting MI to non-MI individuals were 1.52 (range, 1.09-2.10) and 1.54 (range, 1.12-2.10), respectively. After adjustment for use of beta-blocker medication, the odds ratios (95% confidence interval) were 1.26 (range, 0.88-1.81) and 1.22 (range, 0.87-1.69) for lower high-frequency and low-frequency powers, respectively. The findings from this first population-based study of prevalent MI and HRV provide support for an inverse association between MI and lower HRV. However, adjusting for beta-blocker use eliminates the statistical association. These findings confirm that impaired HRV is found in individuals with prevalent MI, even when drawn as a sample of community-dwelling individuals. This impaired HRV may contribute to the increased risk of subsequent cardiovascular events previously observed in survivors of acute MI. The cross-sectional data also suggest that use of beta-blockers diminishes the odds of lower HRV associated with MI.