@article {7436, title = {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.}, journal = {J Am Heart Assoc}, volume = {6}, year = {2017}, month = {2017 Jul 21}, 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{\textpm}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.

}, issn = {2047-9980}, doi = {10.1161/JAHA.116.004305}, author = {Bodapati, Rohan K and Kizer, Jorge R and Kop, Willem J and Kamel, Hooman and Stein, Phyllis K} }