title: [Periodic fluctuations of the blood pressure and heart contraction rate in premature newborn infants].
abstract: To study the postnatal development of circadian rhythm of the blood pressure and the heart rate these parameters were monitored automatically during 24-72 hours at 5h intervals. Fifty infants were investigated at the age 1, 2, 3, and 4 weeks. The results were compared with the cosine curves of different periods (1-48 h) by the IBM PC XT. The fluctuations with all mentioned periods including circadian could be determined in each infant, dominating period being of any duration. In traditional approach the expressiveness of periodical fluctuations is evaluated by the amplitude of cosine curve. Application of the criterion has shown that only amplitude values exceeding 8 mm Hg should be taken into account. Hence, the analysis of BP and HR time series has demonstrated that about 45-50% of the infants have noncircadian rhythms, 20-20% have no significant periodical fluctuations and only 25-30% have circadian rhythm.
authors.forename: E V
authors.initials: EV
authors.lastname: Siutkina
authors.forename: S D
authors.initials: SD
authors.lastname: Timchenko
authors.forename: Sh R
authors.initials: ShR
authors.lastname: Safin
mesh_terms: D000375:Aging / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D005865:Gestational Age; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D008991:Monitoring, Physiologic
vernacular_title: Periodicheskie kolebaniia arterial'nogo davleniia i chastoty serdechnykh sokrashcheniĭ u nedonoshennykh novorozhdennykh.