Analysis of systemic behavior of circulatory system: theoretical study by electrical circuit model

System analysis was applied for total cardiovascular system expressed by linear electrical circuit model. The system was comprised of systemic circulation, pulmonary circulation, arterial and venous circulation. Cardiovascular system was shown to be stable but uncontrollable. The singular values decreased rapidly at physiological frequency range while it showed positive values at low frequency. The amplitude and the duration of oscillation of the impulse responses and the singular values with optimized feedback control were markedly smaller than those without it. Thus in the autonomous state of cardiovascular system, adequate control of venous return is the most critical point to achieve optimal circulatory state. Present investigation must afford some insights to disclose the characteristic properties of cardiovascular system.