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Novel Measures of Heart Rate Variability Predict Cardiovascular Mortality in Older Adults Independent of Traditional Cardiovascular Risk Factors: The Cardiovascular Health Study (CHS)

2008; Wiley; Volume: 19; Issue: 11 Linguagem: Inglês

10.1111/j.1540-8167.2008.01232.x

1540-8167

Phyllis K. Stein, Joshua I. Barzilay, Paulo Chaves, STEPHANIE Q. MISTRETTA, Peter P. Domitrovich, John S. Gottdiener, Michael W. Rich, ROBERT E. KLEIGER,

ECG Monitoring and Analysis

Background: It is unknown whether abnormal heart rate turbulence (HRT) and abnormal fractal properties of heart rate variability identify older adults at increased risk of cardiovascular death (CVdth). Methods: Data from 1,172 community‐dwelling adults, ages 72 ± 5 (65–93) years, who participated in the Cardiovascular Health Study (CHS), a study of risk factors for CV disease in people ≥65 years. HRT and the short‐term fractal scaling exponent (DFA1) derived from 24‐hour Holter recordings. HRT categorized as: normal (turbulence slope [TS] and turbulence onset [TO] normal) or abnormal (TS and/or TO abnormal). DFA1 categorized as low (≤1) or high (>1). Cox regression analyses stratified by Framingham Risk Score (FRS) strata (low = <10, mid = 10–20, and high >20) and adjusted for prevalent clinical cardiovascular disease (CVD), diabetes, and quartiles of ventricular premature beat counts (VPCs). Results: CVdths (N = 172) occurred over a median follow‐up of 12.3 years. Within each FRS stratum, low DFA1 + abnormal HRT predicted risk of CVdth (RR = 7.7 for low FRS; 3.6, mid FRS; 2.8, high FRS). Among high FRS stratum participants, low DFA1 alone also predicted CVdth (RR = 2.0). VPCs in the highest quartile predicted CVdth, but only in the high FRS group. Clinical CV disease predicted CVdth at each FRS stratum (RR = 2.9, low; 2.6, mid; and 1.9, high). Diabetes predicted CVdth in the highest FRS group only (RR = 2.2). Conclusions: The combination of low DFA1 + abnormal HRT is a strong risk factor for CVdth among older adults even after adjustment for conventional CVD risk measures and the presence of CVD.