Interaction between carotid baroregulation and the pulsating heart: a mathematical model

Area of Science:

• Cardiovascular Physiology
• Mathematical Modeling
• Systems Biology

Background:

• Arterial pressure regulation is crucial for tissue perfusion.
• The carotid baroreflex is a primary short-term regulator of blood pressure.
• Understanding these complex interactions requires sophisticated modeling.

Purpose of the Study:

• To develop and validate a mathematical model of short-term arterial pressure control.
• To simulate the interplay between the carotid baroreflex, heart function, and effector mechanisms.
• To investigate the impact of pulsatile flow and hemorrhage on baroreflex control.

Main Methods:

• Developed a comprehensive mathematical model of the cardiovascular system.
• Included detailed descriptions of heart, circulation, baroreceptor pathways, and effector mechanisms.
• Simulated various physiological conditions, including heart pacing and hemorrhage, comparing with experimental data.

Main Results:

• The model demonstrated satisfactory agreement with experimental results.
• Sympathetic-parasympathetic interaction on heart period was found to be linear.
• Pulsatile carotid sinus perfusion reduced baroreflex gain.
• Venous unstressed volume control is critical in early hemorrhage response.

Conclusions:

• The carotid baroreflex significantly influences cardiac function, though often masked in vivo.
• Cardiac output response to heart pacing is frequency-dependent and limited by stroke volume.
• Venous unstressed volume, systemic resistance, and heart rate control are key determinants of hemodynamic stability during hemorrhage.