International Union for Circumpolar Health Ministry of Public Health and Social Development of RF Russian Academy of Medical Sciences Siberian Branch of Russian Academy of Medical Sciences Siberian Branch of Russian Academy of Sciences Medical Polar Fund “Science” The Northern Forum

Abstracts

Cardiovascular diseases

Theoretic background. One of the actual questions in chronomedicine is a study of biologic blood pressure (BP) rhythm in hypertensives living in extreme conditions of the Far North, because the regions of high latitudes have unusual climatogeographic conditions. Aim is to study the circadian rhythm of BP in non-natives of the Far North.

Materials and methods. 24-hour blood pressure monitoring was done on «Tonoport» IVa «Hellige», Germany in 144 hypertensives (103 men, 41 women) living in the Far North (650 of nothern latitude). Mean age was 44,3±0,8 years, period of disease – 6,0±0,5 years, period of living in the Far North 21,8±0,6 years. Circadian BP rhythm was estimated by time index, level of night BP dipping, variability and biorhythm type.

Results. The study showed that together with increase of BP level the percent of time (p<0,001) during which BP indices exceed the critical level also increases. Time index of systolic BP (SBP) increased more intensively – in 3,9 times in average, time index of diastolic BP (DBP) – in 2,4. Time indices of SBP and DBP correlated both with age and period of living in the Far North. “Normal” night BP decrease (>10%) was determined only in 13,0%. “Supernormal” BP decrease at night was found out in 3,7% of cases, in 33,3% of examined persons BP had a tendency to increase at night. In 50,0% the inadequate level of night BP dipping (less then 10,0%) was defined. The higher level of variability in comparison with healthy persons was determined – increase was significant in all periods: day, night, wake-up period (p<0,001). Except “morning” (22,2%) biorhythm type, we defined 4 other biorhythm types in hypertensives: “two-humped” type in 55,6%, “evening” type in 11,1% of cases, “day” and “paradoxal” biorhythm types were defined in 5,55% in both cases.

Conclusion. Circadian BP rhythm in hypertensives in the Far North is characterized by the following peculiarities: - time index: increase of SBP (in 4 times) and DBP (in 2,5 times) tension. - in 83,3% of cases the level of night BP decrease was insufficient. - in 2/3 of hypertensives the variability is increased in the daytime, in the morning and at night. - 5 types of biorhythm, “two-humped” prevails.

Note. Abstracts are published in author's edition

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Last update: 06-Jul-2012 (11:52:05)