Copyright © 2006, European Society of Cardiology
The enigma of Mayer waves: Facts and models
Laboratoire de Physiologie, Faculté de Pharmacie, 8, avenue Rockefeller, Université Claude Bernard Lyon 1, Lyon 69373 Cedex 08, France
* Tel.: +33 478 77 70 72; fax: +33 478 77 71 18. Email address: julien{at}univ-lyon1.fr
Mayer waves are oscillations of arterial pressure occurring spontaneously in conscious subjects at a frequency lower than respiration (
0.1 Hz in humans). Mayer waves are tightly coupled with synchronous oscillations of efferent sympathetic nervous activity and are almost invariably enhanced during states of sympathetic activation. For this reason, the amplitude of these oscillations has been proposed as a surrogate measure of sympathetic activity, although in the absence of a clear knowledge of their underlying physiology. Some studies have suggested that Mayer waves result from the activity of an endogenous oscillator located either in the brainstem or in the spinal cord. Other studies, mainly based on the effects of sinoaortic baroreceptor denervation, have challenged this view. Several models of dynamic arterial pressure control have been developed to predict Mayer waves. In these models, it was anticipated that the numerous dynamic components and fixed time delays present in the baroreflex loop would result in the production of a resonant, self-sustained oscillation of arterial pressure. Recent analysis of the various transfer functions of the rat baroreceptor reflex suggests that Mayer waves are transient oscillatory responses to hemodynamic perturbations rather than true feedback oscillations. Within this frame, the amplitude of Mayer waves would be determined both by the strength of the triggering perturbations and the sensitivity of the sympathetic component of the baroreceptor reflex.
KEYWORDS Autonomic nervous system; Baroreflex; Blood pressure
1 The slow AP oscillations originally described by S. Mayer in anesthetized rabbits [1] had a frequency of 6 to 9 cycles/min, i.e., 0.1 to 0.15 Hz, which is slower than the frequency of spontaneous sympathetically mediated AP oscillations in conscious rabbits (0.3 Hz). The term Mayer wave is therefore incorrect, but shall be used here due to its widespread use in this way.