ASSOCIATION OF CARDIAC AUTONOMIC FUNCTION AND THE DEVELOPMENT OF HYPERTENSION - THE ARC STUDY

To relate cardiac autonomic function measured by heart rate variabilit y (HRV) with prevalent and incident hypertension at the population lev el, the authors examined a stratified random sample of 2,061 examinees from the biracial Atherosclerosis Risk in Communities (ARIC) cohort. Baseline, supine, resting beat-to-beat heart rate data were collected. High frequency (HF, 0.15 to 0.35 Hz), low frequency (LF, 0.025 to 0.1 5 Hz) spectral powers, and LF/HF ratio, estimated from spectral analys is, and standard deviation of all normal RR intervals (SDNN), calculat ed from time domain analysis, were used as the conventional indices of cardiac autonomic function. From this sample, 650 prevalent hypertens ives were identified. Of those normotensive at baseline (n = 1,338), 6 4 participants developed hypertension during 3 years of follow-up. In the cross-sectional analysis, the adjusted geometric means of HF were 1.26, 1.20, and 1.00 (beat/min)(2) for normotensives, untreated hypert ensives, and treated hypertensives, respectively; means of LF were 3.2 4, 3.26, and 2.58; means of LF/HF ratio were 2.57, 2.70, and 2.56; and means of SDNN were 39, 34, and 35 (ms) respectively. In the prospecti ve analysis, a statistically significant, graded inverse association b etween baseline HF and the risk of incident hypertension was observed: the adjusted incident odds ratios (95% CI) were 1.00, 1.46 (0.61, 3.4 6), 1.50 (0.65, 3.50) and 2.44 (1.15, 5.20) from the highest to the lo west quartile of HF. No clear pattern of association was observed for LF. Significant trends of association for LF/HF and SDNN and incident hypertension were also found. These results suggest that cardiac auton omic function is associated with prevalent hypertension, and that redu ced vagal function and the imbalance of sympatho-vagal function are as sociated with the risk of developing hypertension. (C) 1996 American J ournal of Hypertension, Ltd.