Abstract
The reported circadian rhythm of blood pressure variability with a rise in pressure before awakening has been the subject of controversy. Previous studies have suggested that since heart rate continues to fall before awakening while blood pressure is rising these physiological variables are subject to different control mechanisms. To evaluate further the dissociation of heart rate and blood pressure changes in a group of patients with a fixed heart rate, 11 patients who were dependent on ventricular demand pacemakers underwent intra-arterial ambulatory blood pressure monitoring. Nine aged matched control subjects followed the same protocol. Circadian curves plotted from pooled hourly mean data showed that despite a fixed heart rate the circadian pattern persisted, although attenuated, with blood pressure rising several hours before its rapid rise on awakening. Physiological testing showed that despite a fixed heart rate systolic blood pressure rose in response to bicycle exercise, there was a postural fall in the blood pressure on tilting and a modified Valsalva response. There was considerable beat to beat variability resulting presumably from asychronous pacing. Hour to hour changes did not contribute to the differences between the two groups and were not responsible for attenuation of the circadian rhythm. It is concluded that blood pressure and heart rate control mechanisms may be dissociated, particularly in the period before awakening.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Cashman P. M., Stott F. D., Craig M. W. Hybrid system for fast data reduction of long-term blood-pressure recordings. Med Biol Eng Comput. 1979 Sep;17(5):629–635. doi: 10.1007/BF02440908. [DOI] [PubMed] [Google Scholar]
- Floras J. S., Jones J. V., Johnston J. A., Brooks D. E., Hassan M. O., Sleight P. Arousal and the circadian rhythm of blood pressure. Clin Sci Mol Med Suppl. 1978 Dec;4:395s–397s. doi: 10.1042/cs055395s. [DOI] [PubMed] [Google Scholar]
- Millar-Craig M. W., Bishop C. N., Raftery E. B. Circadian variation of blood-pressure. Lancet. 1978 Apr 15;1(8068):795–797. doi: 10.1016/s0140-6736(78)92998-7. [DOI] [PubMed] [Google Scholar]
- Millar-Craig M. W., Hawes D., Whittington J. New system for recording ambulatory blood pressure in man. Med Biol Eng Comput. 1978 Nov;16(6):727–731. doi: 10.1007/BF02442453. [DOI] [PubMed] [Google Scholar]
- Rowlands D. B., Stallard T. J., Watson R. D., Littler W. A. The influence of physical activity on arterial pressure during ambulatory recordings in man. Clin Sci (Lond) 1980 Jan;58(1):115–117. doi: 10.1042/cs0580115. [DOI] [PubMed] [Google Scholar]
- SAMET P., BERNSTEIN W., LEVINE S. SIGNIFICANCE OF THE ATRIAL CONTRIBUTION TO VENTRICULAR FILLING. Am J Cardiol. 1965 Feb;15:195–202. doi: 10.1016/0002-9149(65)90454-6. [DOI] [PubMed] [Google Scholar]
- SELDINGER S. I. Catheter replacement of the needle in percutaneous arteriography; a new technique. Acta radiol. 1953 May;39(5):368–376. doi: 10.3109/00016925309136722. [DOI] [PubMed] [Google Scholar]
- SOWTON E. HAEMODYNAMIC STUDIES IN PATIENTS WITH ARTIFICIAL PACEMAKERS. Br Heart J. 1964 Nov;26:737–746. doi: 10.1136/hrt.26.6.737. [DOI] [PMC free article] [PubMed] [Google Scholar]