Phase synchronization of baroreflex oscillations of blood pressure and pulse interval in rats: the effects of cardiac autonomic blockade and gradual blood loss

Abstract

The analysis of hemodynamic variability is a powerful tool in the assessment of autonomic control of the heart and vasculature. Arterial baroreflex is an important mechanism of short-term cardiovascular control, therefore, oscillations that reflect the functioning of the arterial baroreflex have been addressed in many studies (Cerutti

Phase Coupling Between Baroreflex Oscillations of Blood Pressure and Heart Rate Changes in 21-Day Dry Immersion

“…To evaluate the changes in the cardiac baroreflex during simulated gravitational unloading, we used a novel approach based on estimation of the phase relations of BP and HR fluctuations in the frequency range of baroreflex waves (Borovik et al, 2014(Borovik et al, , 2019Negulyaev et al, 2019). Importantly, the observed changes in cardiac baroreflex sensitivity during orthostasis depend on the method of assessing baroreflex activity.…”

“…This method of analysis has several important advantages, since it provides more stable results than traditional methods (such as cross-spectral analysis) and does not require long continuous recording (Negulyaev et al, 2019). According to our previous data, PSI of blood pressure and HR in baroreflex frequency range increased significantly during orthostatic challenge in volunteers (Borovik et al, 2014) as well as during central hypovolemia induced by hemorrhage in laboratory rats (Negulyaev et al, 2019).…”

“…For this purpose, PSI of MAP and HR was calculated. The algorithm of PSI calculation was described in detail in our previous works (Borovik et al, 2014;Negulyaev et al, 2019). In brief, MAP and HR were resampled at 5 Hz using linear interpolation, then narrow-band signals were extracted by digital filtering from the obtained time series.…”

“…Noteworthy, the complex dynamics of physiological signals is also determined by their phase relationships. In this study, we introduce a novel approach to the assessment of baroreflex activity, based on the calculation of the phase relations of blood pressure and HR oscillations at the frequency of baroreflex waves using the phase synchronization index (PSI) (Borovik et al, 2014(Borovik et al, , 2019Negulyaev et al, 2019). This method of analysis has several important advantages, since it provides more stable results than traditional methods (such as cross-spectral analysis) and does not require long continuous recording (Negulyaev et al, 2019).…”

“…In this study, we introduce a novel approach to the assessment of baroreflex activity, based on the calculation of the phase relations of blood pressure and HR oscillations at the frequency of baroreflex waves using the phase synchronization index (PSI) (Borovik et al, 2014(Borovik et al, , 2019Negulyaev et al, 2019). This method of analysis has several important advantages, since it provides more stable results than traditional methods (such as cross-spectral analysis) and does not require long continuous recording (Negulyaev et al, 2019). According to our previous data, PSI of blood pressure and HR in baroreflex frequency range increased significantly during orthostatic challenge in volunteers (Borovik et al, 2014) as well as during central hypovolemia induced by hemorrhage in laboratory rats (Negulyaev et al, 2019).…”