The influence of heart rate on augmentation index and central arterial pressure in humans

Ian B. Wilkinson*, Helen MacCallum, Laura Flint, John R. Cockcroft, David E. Newby, David J. Webb

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

763 Citations (Scopus)

Abstract

1. Arterial stiffness is an important determinant of cardiovascular risk. Augmentation index (AIx) is a measure of systemic arterial stiffness derived from the ascending aortic pressure waveform. The aim of the present study was to assess the effect of heart rate on AIx. We elected to use cardiac pacing rather than chronotropic drugs to minimize confounding effects on the systemic circulation and myocardial contractility. 2. Twenty-two subjects (13 male) with a mean age of 63 years and permanent cardiac pacemakers in situ were studied. Pulse wave analysis was used to determine central arterial pressure waveforms, non-invasively, during incremental pacing (from 60 to 110 beats min-1), from which AIx and central blood pressure were calculated. Peripheral blood pressure was recorded non-invasively from the brachial artery. 3. There was a significant, inverse, linear relationship between AIx and heart rate (r = -0.76; P < 0.001). For a 10 beats min-1 increment, AIx fell by around 4%. Ejection duration and heart rate were also inversely related (r = -0.51; P < 0.001). 4. Peripheral systolic, diastolic and mean arterial pressure increased significantly during incremental pacing. Although central diastolic pressure increased significantly with pacing, central systolic pressure did not. There was a significant increase in the ratio of peripheral to central pulse pressure (P < 0.001), which was accounted for by the observed change in central pressure augmentation. 5. These results demonstrate an inverse, linear relationship between AIx and heart rate. This is likely to be due to alterations in the timing of the reflected pressure wave, produced by changes in the absolute duration of systole. Consideration of wave reflection and aortic pressure augmentation may explain the lack of rise in central systolic pressure during incremental pacing despite an increase in peripheral pressure.

Original languageEnglish
Pages (from-to)263-270
Number of pages8
JournalJournal of Physiology
Volume525
Issue number1
Publication statusPublished - 15 May 2000

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