@article {859, title = {Sometimes higher heart rate variability is not better heart rate variability: results of graphical and nonlinear analyses.}, journal = {J Cardiovasc Electrophysiol}, volume = {16}, year = {2005}, month = {2005 Sep}, pages = {954-9}, abstract = {

OBJECTIVE: To determine the prevalence and effect on traditional heart rate variability (HRV) indices of abnormal HRV patterns in the elderly.

METHODS: Hourly Poincar{\'e} plots and plots of spectral HRV from normal-to-normal interbeat intervals and hourly nonlinear HRV values were examined in a subset of 290 consecutive participants in the Cardiovascular Health Study. Only subjects in normal sinus rhythm with > or = 18 hours of usable data were included. Eligible subjects were 71 +/- 5 years. During 7 years of follow-up, 21.7\% had died. Hours were scored as normal (0), borderline (0.5), or abnormal (1) from a combination of plot appearance and HRV. Summed scores were normalized to 100\% to create an abnormality score (ABN). Short-term HRV versus each 5th percentile of ABN was plotted and a cutpoint for markedly increased HRV identified. The t-tests compared HRV for subjects above and below this cutpoint. Cox regression evaluated the association of ABN and mortality.

RESULTS: Of 5,815 eligible hourly plots, 64.4\% were normal, 14.5\% borderline, and 21.1\% abnormal. HR, SDNN, SDNNIDX, ln VLF and LF power, and power law slope did not differ by the cutpoint for increased short-term HRV, while SDANN and ln ULF power were significantly lower for those above the cutpoint. However, many HRV indices including LF/HF ratio and normalized LF and HF power were significantly different between groups (P < 0.001). Increased ABN was significantly associated with mortality (P = 0.019). Despite similar values for many HRV indices, being in the group above the cutpoint was significantly associated with mortality (P = 0.04).

CONCLUSIONS: Abnormal HR patterns that elevate many HRV indices are prevalent among the elderly and associated with higher risk of mortality. Consideration of abnormal HRV may improve HRV-based risk stratification.

}, keywords = {Aged, Aged, 80 and over, Algorithms, Arrhythmia, Sinus, Cohort Studies, Diagnosis, Computer-Assisted, Electrocardiography, Female, Heart Rate, Humans, Male, Models, Cardiovascular, Nonlinear Dynamics, Numerical Analysis, Computer-Assisted, Prevalence, Proportional Hazards Models, Reproducibility of Results, Risk Assessment, Risk Factors, Sensitivity and Specificity, United States}, issn = {1045-3873}, doi = {10.1111/j.1540-8167.2005.40788.x}, author = {Stein, Phyllis K and Domitrovich, Peter P and Hui, Nelson and Rautaharju, Pentti and Gottdiener, John} } @article {1008, title = {Higher levels of inflammation factors and greater insulin resistance are independently associated with higher heart rate and lower heart rate variability in normoglycemic older individuals: the Cardiovascular Health Study.}, journal = {J Am Geriatr Soc}, volume = {56}, year = {2008}, month = {2008 Feb}, pages = {315-21}, abstract = {

OBJECTIVES: To explore the relationship between (1) insulin resistance and inflammation factors with (2) higher heart rate (HR) and lower heart rate variability (HRV) in normoglycemic older adults.

DESIGN: Cross-sectional population-based study.

PARTICIPANTS: Five hundred forty-five adults aged 65 and older with normoglycemia (fasting glucose <100 mg/dL) who participated in the Cardiovascular Health Study.

MEASUREMENTS: Serum levels of three inflammation proteins (C-reactive protein (CRP), interleukin 6 (IL-6), and fibrinogen); insulin resistance, quantified according to the homeostasis assessment model (HOMA-IR); HR; and four representative measures of HRV (the standard deviation of normal beat to beat intervals (SDNN), the root mean square of successive differences (rMSSD), very low frequency power (VLF), and the low- to high-frequency power ratio (LF/HF)) derived from 24-hour Holter recordings.

RESULTS: High CRP and IL-6 levels were associated with higher HR and lower SDNN and VLF after adjustment for multiple covariates, including HOMA-IR and clinical cardiovascular disease. High IL-6 was also associated with lower LF/HF. Significant univariate inverse relationships between HOMA-IR and HR and HRV were also found, but the strengths of these relationships were attenuated after adjustment for inflammation factors.

CONCLUSION: Increased levels of inflammation markers and HOMA-IR are associated with higher HR and lower HRV. These findings suggest that inflammation may contribute to the pathogenesis of cardiovascular autonomic decline in older adults.

}, keywords = {Aged, C-Reactive Protein, Cardiovascular Diseases, Cross-Sectional Studies, Electrocardiography, Ambulatory, Female, Fibrinogen, Heart Rate, Humans, Inflammation Mediators, Insulin Resistance, Interleukin-6, Male, Risk Factors}, issn = {1532-5415}, doi = {10.1111/j.1532-5415.2007.01564.x}, author = {Stein, Phyllis K and Barzilay, Joshua I and Chaves, Paulo H M and Traber, Jennifer and Domitrovich, Peter P and Heckbert, Susan R and Gottdiener, John S} } @article {1042, title = {Novel measures of heart rate variability predict cardiovascular mortality in older adults independent of traditional cardiovascular risk factors: the Cardiovascular Health Study (CHS).}, journal = {J Cardiovasc Electrophysiol}, volume = {19}, year = {2008}, month = {2008 Nov}, pages = {1169-74}, abstract = {

UNLABELLED: Novel HRV Predicts CV Mortality in the Elderly.

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 >or=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). 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.

}, keywords = {Aged, Aged, 80 and over, Arrhythmias, Cardiac, Death, Sudden, Cardiac, Electrocardiography, Ambulatory, Female, Heart Rate, Humans, Male, Maryland, Reproducibility of Results, Risk Assessment, Risk Factors, Sensitivity and Specificity, Survival Analysis, Survival Rate}, issn = {1540-8167}, doi = {10.1111/j.1540-8167.2008.01232.x}, author = {Stein, Phyllis K and Barzilay, Joshua I and Chaves, Paulo H M and Mistretta, Stephanie Q and Domitrovich, Peter P and Gottdiener, John S and Rich, Michael W and Kleiger, Robert E} } @article {1069, title = {Heart rate variability and its changes over 5 years in older adults.}, journal = {Age Ageing}, volume = {38}, year = {2009}, month = {2009 Mar}, pages = {212-8}, abstract = {

PURPOSE: to characterise the association between age, ageing and heart rate variability (HRV) in older individuals, 585 adults age >65 years with two 24-h Holter recordings in the Cardiovascular Health Study were studied.

METHODS: heart rate (HR), ventricular premature contractions (VPCs), atrial premature contractions (APCs), frequency-domain, ratio-based and non-linear HRV and heart rate turbulence (HRT) were examined cross-sectionally by 5-year age groups and prospectively over 5 years. Analyses adjusted for gender, lower versus elevated cardiovascular (CV) risk and for the change in CV risk.

RESULTS: HR declined, and VPCs and APCs increased per 5-year increase in age. Frequency-domain HRV decreased more at 65-69, less at 70-74 and minimally at > or =75 years, independent of CVD risk or change in CVD risk. Ratio and non-linear HRV continued to decline to > or =75 years old. Ratio HRV and HRT slope were more strongly related to CVD risk than frequency-domain HRV.

CONCLUSIONS: cardiac autonomic function, assessed by frequency-domain HRV, declines most at 65-70 and levels off at age >75. The decline is independent of CVD risk or change in CVD risk. Ratio-based and non-linear HRV and HRT slope continued to change with increasing age and were more closely related to CVD risk than frequency-domain HRV.

}, keywords = {Age Distribution, Aged, Aging, Atrial Premature Complexes, Autonomic Nervous System, Cardiovascular Diseases, Cross-Sectional Studies, Electrocardiography, Ambulatory, Female, Heart Rate, Humans, Hypertension, Male, Nonlinear Dynamics, Prevalence, Prospective Studies, Risk Factors, Ventricular Premature Complexes}, issn = {1468-2834}, doi = {10.1093/ageing/afn292}, author = {Stein, Phyllis K and Barzilay, Joshua I and Chaves, Paulo H M and Domitrovich, Peter P and Gottdiener, John S} }