FREQUENCY-SHIFT IN BAROREGULATORY OSCILLATION IN BORDERLINE HYPERTENSIVE SUBJECTS

The aim of this study was to quantify the frequency shift in vasomotor oscillations in blood pressure we observed in borderline hypertensive individuals in our previous study. Electrocardiogram and intraarteria l blood pressure were recorded in 33 normotensive, 29 borderline hyper tensive, and 33 mildly hypertensive men (aged 35 to 45 years). Five-mi nute stationary periods in supine, sitting, and standing positions, an d during sleep were extracted from the recordings for autoregressive f requency domain analysis. In borderline hypertensive subjects vasomoto r oscillations in the range of 0.05 to 0.12 Hz in blood pressure and h eart rate, assumed to be associated with baroreceptor activity, were s hifted to lower values as compared with the other two groups. The freq uency shift was assessed by median frequency of the oscillations. Sign ificant between-group differences were observed in the supine and sitt ing positions, No significant between-group differences were seen in n ormalized spectral power estimates. Further studies are required to de termine whether the frequency shift provides prognostic information on cardiovascular morbidity. (C) 1997 American Journal of Hypertension, Ltd.