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J Am Heart Assoc. 2017 Jul 21;6(7). pii: e004305. doi: 10.1161/JAHA.116.004305.

Addition of 24-Hour Heart Rate Variability Parameters to the Cardiovascular Health Study Stroke Risk Score and Prediction of Incident Stroke: The Cardiovascular Health Study.

Author information

1
Heart Rate Variability Laboratory, Washington University School of Medicine, St. Louis, MO.
2
Department of Medicine (Cardiology), Albert Einstein College of Medicine, Bronx, NY.
3
Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY.
4
Department of Medical Psychology and Neuropsychology, Center for Research on Psychology in Somatic Diseases, Tilburg University, Tilburg, Netherlands.
5
Department of Neurology, Weill Cornell Medical College, New York, NY.
6
Heart Rate Variability Laboratory, Washington University School of Medicine, St. Louis, MO pstein@wustl.edu.

Abstract

BACKGROUND:

Heart rate variability (HRV) characterizes cardiac autonomic functioning. The association of HRV with stroke is uncertain. We examined whether 24-hour HRV added predictive value to the Cardiovascular Health Study clinical stroke risk score (CHS-SCORE), previously developed at the baseline examination.

METHODS AND RESULTS:

N=884 stroke-free CHS participants (age 75.3±4.6), with 24-hour Holters adequate for HRV analysis at the 1994-1995 examination, had 68 strokes over ≤8 year follow-up (median 7.3 [interquartile range 7.1-7.6] years). The value of adding HRV to the CHS-SCORE was assessed with stepwise Cox regression analysis. The CHS-SCORE predicted incident stroke (HR=1.06 per unit increment, P=0.005). Two HRV parameters, decreased coefficient of variance of NN intervals (CV%, P=0.031) and decreased power law slope (SLOPE, P=0.033) also entered the model, but these did not significantly improve the c-statistic (P=0.47). In a secondary analysis, dichotomization of CV% (LOWCV% ≤12.8%) was found to maximally stratify higher-risk participants after adjustment for CHS-SCORE. Similarly, dichotomizing SLOPE (LOWSLOPE <-1.4) maximally stratified higher-risk participants. When these HRV categories were combined (eg, HIGHCV% with HIGHSLOPE), the c-statistic for the model with the CHS-SCORE and combined HRV categories was 0.68, significantly higher than 0.61 for the CHS-SCORE alone (P=0.02).

CONCLUSIONS:

In this sample of older adults, 2 HRV parameters, CV% and power law slope, emerged as significantly associated with incident stroke when added to a validated clinical risk score. After each parameter was dichotomized based on its optimal cut point in this sample, their composite significantly improved prediction of incident stroke during ≤8-year follow-up. These findings will require validation in separate, larger cohorts.

KEYWORDS:

autonomic nervous system; clinical stroke risk model; heart rate variability; prediction; predictors; risk prediction; risk stratification; stroke

PMID:
28733431
PMCID:
PMC5586256
DOI:
10.1161/JAHA.116.004305
[Indexed for MEDLINE]
Free PMC Article

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