Modeling Human Systemic Arterial Tree with Electric Components in the 1960s and Today

Analog and theoretical models were widely used in the 1960s to study physiological systems. But how relevant are these approaches today, and what insights can we still gain from analog and physical modeling of the human body? In our work, we re-created the analog computing logic in circuit simulation representing the arterial tree and successfully reproduced the waveforms of blood flow, pressure, and displacement ballistocardiogram (BCG) as described by Noordergraaf et al. and Westerhof et al., albeit with some variations. We hypothesize that these discrepancies arise from the limited sensitivity of the oscillometry and the accuracy of the electrical components available at the time of the original study. Nevertheless, the striking similarity between the physical models of the 1960s and our recreated models highlights the robustness and accuracy of their theoretical framework, demonstrating the value of these early approaches in understanding cardiovascular dynamics.