[Development of arterial pressure rhythm and cardiac contraction rate and effects of beta-adrenomimetic agents]. / Stanovlenie ritmov arterial'nogo davleniia i chastoty serdechnykh sokrashchenii i vliianie beta-adrenomimetikov.

Blood pressure (BP) and heart rate (HR) rhythms were studied in premature infants (299 profiles ranged 24-106 h at 20--min intervals) and 11-13-year-old children (19 profiles for 48 h at 15-min intervals) to explore ultradian-to-circannual rhythm characteristics in BP and HR in preterm human infant and to elucidate the influence of antenatal betamimetic (BM) exposure on adolescent BP and HR rhythms. A circannual modulation of the 3-h amplitude (A) or MESOR of systolic BP (SBP) and diastolic BP (DBP) was seen mainly in prematures with a positive family history of high BP on the father's (f+) side or with both a patro linous and matro-linous history (f+m+), the circannual modulation of HR ultradian A was statistically significant only in "f- m-" infants. In urine collected at 3 h intervals for 24-h spans from 21 premature infants Na+,K+ and 11-oxycorticosteroids had a significant circadian rhythm. 9 adolescents (BM+), which were exposed in utero to different BM doses, had a significantly higher SBP and DBP MESOR and numerically higher circadian A as compared to 10 controls (BM-); correlation (P less than 0.05) between BM dose and HR circadian A was found. DBP led SBP in 8 or 10 "BM-" but in 4 of 9 "BM+" (acrophase difference 17 min and 3 min correspondingly).(ABSTRACT TRUNCATED AT 250 WORDS)