Cardiovascular variability is/is not an index of autonomic control of circulation

Abstract

POINT-COUNTERPOINT COMMENTSCardiovascular variability is/is not an index of autonomic control of circulationJohn M. KaremakerJohn M. KaremakerPublished Online:01 Sep 2006https://doi.org/10.1152/japplphysiol.00643.2006This is the final version - click for previous versionMoreSectionsPDF (24 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations The following letter is in response to the Point:Counterpoint series “Cardiovascular variability is/is not an index of autonomic control of circulation” that appeared in the August issue (vol. 101: 676-682, 2006; http://jap.physiol.org/content/vol101/issue2/2006).To the Editor: The Point:Counterpoint discussion on CVV (4) caught my attention as it raises a number of questions about which I also have philosophized in the past (1–3). However interesting the arguments that are put forward, the only difference between the two P:CP camps seems to be the conclusion: may we or may we not use CVV-derived parameters in daily clinical practice? Strangely enough, no one ever questions the outcome of classical autonomic function tests, like the phenylephrine test (5) to “measure” baroreflex sensitivity. Anyone who ever did the test knows that a difference of a factor of two in outcome between successive runs is not uncommon. Underpinning the fact that autonomic outflow from the CNS may be highly variable from moment to moment. Only in neuropathy or after brain injury do we find stable (mostly low) outflow. Continuous variability in nervous activity is a fact of life, and quantification by direct (MSNA) or indirect measurement (CVV) may give only rough estimates of a patients' condition. Much less exact than the concentration of ions in the blood, but telltale when longer periods of illness in one and the same patient are to be followed. There lies, in my opinion, the true power of clinical application of CVV, not in the one-point measurement, unless the condition is extremely clear cut.REFERENCES1 Karemaker JM. Heart rate variability: why do spectral analysis? Heart 77: 99–101, 1997.Crossref | ISI | Google Scholar2 Karemaker JM. The riddles of heart rate variability. Clin Auton Res 11: 65–66, 2001.Crossref | ISI | Google Scholar3 Karemaker JM. Why do we measure baroreflex sensitivity the way we do? Clin Auton Res 12: 427–428, 2002.Crossref | ISI | Google Scholar4 Parati G, Di Rienzo M, Castiglioni P, and Mancia G; Taylor JA and Studinger P. Point:Counterpoint: Cardiovascular variability is/is not an index of autonomic control of circulation. J Appl Physiol 101: 676–682, 2006.Link | ISI | Google Scholar5 Smyth HS, Sleight P, and Pickering GW. Reflex regulation of arterial pressure during sleep in man. A quantitative method of assessing baroreflex sensitivity. Circ Res 24: 109–121, 1969.Crossref | PubMed | ISI | Google Scholar Download PDF Previous Back to Top Next FiguresReferencesRelatedInformation Cited ByDifferent equestrian sports horses’ reactivity to startleJournal of Veterinary Behavior, Vol. 57Influence of Heart Rate in Non-linear HRV Indices as a Sampling Rate Effect Evaluated on Supine and Standing15 November 2016 | Frontiers in Physiology, Vol. 7Respiratory and non-respiratory sinus arrhythmia: implications for heart rate variability25 December 2011 | Journal of Clinical Monitoring and Computing, Vol. 26, No. 1 More from this issue > Volume 101Issue 3September 2006Pages 1003-1003 Copyright & PermissionsCopyright © 2006 the American Physiological Societyhttps://doi.org/10.1152/japplphysiol.00643.2006PubMed16825523History Published online 1 September 2006 Published in print 1 September 2006 Metrics