Integration of the carotid baroreflex with a simple pulsatile cardiovascular model

A mathematical model of short-term arterial pressure regulation by the carotid baroreflex was integrated with a simple cardiovascular model to study the interactions between the baroreguation and the pusating heart. The cardiovascular system was modeled as an electric circuit, consisting of the left ventricle as a time-varying capacitance, the systemic circulation as a four-element RLC circuit, the pulmonary circulation as a constant capacitor with a dependent current source, the left atrium as a constant capacitor, and the heart valves as ideal diodes in series with resistors. The baroreflex model receives the systemic arterial pressure to adjust the heart rate, the maximum elastance of the left ventricle, the systemic vascular resistance, and the unstressed blood volume in the systemic vein, and thus maintain the mean arterial pressure close to its setpoint. The key hemodynamic variables simulated from this integrated model were closed to their values provided in literature. Validation tests also suggested that this simple model could simulate the baroregulation phenomena very similar to that obtained from a detailed cardiovascular model. This model can be used as a tool in applications such as pathology and medical device development in which a simple cardiovascular model provides the advantages.