Abstract 2305: Decreased Heart Rate Variability, a Measure of Autonomic Dysfunction, is Associated with Higher Levels of Inflammation as Measured by IL-6
Background: Many traditional risk factors for coronary artery disease (CAD) are associated with altered autonomic function. Inflammation may provide a link between traditional risk factors, autonomic dysfunction, and CAD. We examined the association between heart rate variability (HRV), a measure of autonomic function, and inflammation, measured by IL-6.
Methods: We examined 224 middle-aged male twins free of symptomatic CAD. All underwent ambulatory ECG monitoring, (Holter) and 24-hour ULF, VLF, LF, and HF were calculated using power spectral analysis and log-normalized for analysis. IL-6 was measured. Subjects were assessed for traditional risk factors including age, smoking, hypertension, lipids, diabetes, body mass index (BMI), and physical activity (Baecke). GEE modeling was used for multivariable analysis while taking into account intra-pair variability and zygosity.
Results: The mean age was 53.8 ± 2.7 years, mean HDL, 39.0 ± 9.7mg/dl, mean BMI 29.3 ± 4.98 kg/m2. Hypertension was present in 101 (45%) and diabetes in 26 (12%) subjects. There was a graded inverse relationship between all HRV parameters (except HF) and IL-6 (see graph). Diabetes, hypertension, cholesterol, BMI, and physical activity were associated with both HRV and inflammatory markers. In multivariable analysis adjusting for these clinical factors as well as age and heart rate, ULF and VLF each remained significantly associated with IL-6 (β− 0.22, p=0.004, and β −0.32, p=0.003, respectively).
Conclusion: Autonomic dysfunction is associated with increased inflammation, which may represent a pathway through which traditional risk factors increase inflammation and CAD risk.