Modeling of Mayer waves generation mechanisms

The observed fluctuations in heart rate and blood pressure are meaningful rhythmical fluctuations that reflect useful information about autonomic regulation. These rhythmical fluctuations, known as heart rate variability (HRV) and blood pressure variation (BPV), are normally grouped into three major components: (i) the HF component, around 0.25 Hz, in synchrony with respiratory rate; (ii) the LF component, generally centered around 0.1 Hz, which is attributed to the sympathetic activity and the closed-loop controlling action of cardiovascular regulation; (iii) the VLF component, around 0.04 Hz, which is probably due to the vasorhythmicity thermoregulatory system or to humoral regulations. Unlike the HF component, there is still considerable controversy with regard to the origin of LF and VLF components, the so-called Mayer waves. Finding a model to represent the LF and VLF components in an appropriate manner, compatible with the relevant physiology, is the objective of this article. For this purpose, we first briefly review the underlying physiological mechanisms. Then, an appropriate mathematical representation for each mechanism is demonstrated and its performance within a comprehensive model of the cardiovascular regulatory system is considered. Finally, by comparing with the experimental results, we evaluate the closeness of the proposed representations to the actual observations.