Abstract 430: Blood Pressure Monitoring in the Biological Time Structures and in Pre- /Post-Surgery Seasonal Variations

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Biological time structures (clock-hour), including yearly rhythm (circannual), ~weekly (circaseptan) and circadian are considered essential parameters in blood pressure (BP) to recognize and treat any risk elevation as well as overt disease. BP and heart rate (HR) in adolescents and adults were monitored automatically around the clock at 30-minute to hourly intervals for seasons and/or years. Data was analyzed by the linear least square rhythmometry. All showed significant circadian fluctuations in BP and HR. BP was about 10-20 mm Hg higher in the adult group while HR was lowered in average about 10 beats/min. The circadian response peaked in the noon to the late afternoon hours: SBP: 18:08; DBP: 17:08; HR: 17:40 with the impression from the 5 adult subjects, individual differences notwithstanding, while one teen showed shift changes to the early morning hours: SBP: 01:48; DBP: 01:24: HR: 00:12. Circannual BP and HR revealed significant rhythms with peaks on October 27 (SBP), November 26 (DBP) and October 31 (HR). While the winter month BP and HR were the lowest in comparison to the other 3 seasons, further sudden drops of both BP and HR were noted in the individual at the point of surgery in mid-January. However, when the surgery performed in the same individual in November, the drop was minimal, while early spring time surgery increased SBP significantly with a minimal increase in DBP and HR. Sharp increased double amplitudes (Amps) (SBP 73; DBP 35; HR 24, all P<0.0001) observed in the winter season. The circaseptan double Amps in the adolescent were 13 ± 4 (P=0.019) for SBP and 8 ± 3 mm Hg (P=0.030) for DBP, with acrophases occurring on late Sunday, early Monday (at -50° and -67° from 00:00 on Saturday to Sunday for SBP and DBP, respectively, with 360° ≡ 1 week). Post-OP Amps were significantly shallow compared with control: SBP: 45 vs. 19; DBP: 21 vs. 6; HR: 21 vs. 12 mm Hg, while acrophase (peak hrs) was various: pre-/post-op SBP: 16:44 vs. 11:32; DBP: 11:44 vs. 01:16; HR: 11:44 vs. 13:08 hrs. The increased or shallow Amp can be a predictable risk factor of CVD. Circaseptan acrophases coincide with the time of increased vascular morbidity/mortality in our studies. Chronomes broader than circadian should be considered in interpreting BP responses as a gauge of vascular disease status.

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