Cohort Study of Heart Rate Variability
Condition: Cardiovascular Diseases; Myocardial Ischemia; Carotid Stenosis; Hypertension; Diabetes Mellitus; Heart Diseases
MeSH terms: Carotid Stenosis; Cardiovascular Diseases; Heart Diseases; Myocardial Ischemia; Ischemia
Study type: Observational

Summary: 
      To examine factors affecting heart rate variability (HRV) and the role of HRV in heart
      disease. Specifically, to examine the role of HRV: as a predictor of fatal and nonfatal
      ischemic heart disease over a six year follow-up of the Atherosclerosis Risk in Communities
      (ARIC) population based, bi-ethnic cohort; on the six year progression of carotid
      atherosclerosis measured by B-mode ultrasound; and on the incidence of hypertension. Also, to
      study the effect of elevated fasting insulin, glucose, diabetes mellitus, and other metabolic
      abnormalities on changes in HRV over nine years of follow-up.
    

Detailed description: 
      BACKGROUND:

      Heart rate variability analysis has been widely used in clinical research as a noninvasive
      measurement of autonomic function. It has been found to be associated with post-myocardial
      infarction mortality, hypertension, sudden cardiac death, atherosclerosis, and diabetes.
      However, little epidemiologic research on HRV had been reported prior to this study in 1996.
      Almost no data were available on the population distribution of HRV, its correlates in
      populations, the factors associated with changes in HRV over time, or on the cardiovascular
      sequelae of impaired autonomic function assessed by HRV obtained from population-based
      prospective studies.

      DESIGN NARRATIVE:

      The study was ancillary to ARIC, a population-based, longitudinal study of cardiovascular and
      pulmonary diseases. The baseline exam was completed in 1987 to 1988, followed by yearly
      contacts and re-examinations every three years. The present study built on the data collected
      by the ARIC investigators by retrieving and processing beat-to-beat heart rate data collected
      during the baseline exam. Five minutes of beat-to-beat heart rate data were obtained from the
      ARIC cohort participants during their third follow-up visit (Visit) 4 in 1996 through 1998.
      Time and frequency domain HRV indices were derived for an assessment of autonomic function.
      The following HRV indices were computed both for the baseline and the nine-year follow-up
      exam (1996 through 1998) on the 13,000 members of the ARIC cohort: time domain indices; mean
      heart rate, minimum and maximum heart rate, standard deviation of all normal R-R intervals,
      the coefficient of variation of all normal R-R intervals, root mean square of the differences
      of successive R-R intervals, and the proportion of adjacent R-R intervals. Frequency domain
      indices were also computed, including high frequency power, low frequency power, and the
      high/low frequency power ratio.
    

Intervention name(s): No interventions
Intervention type(s): Other
Intervention description(s): No interventions
Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        Population-based sample of adults ages 45-64 years