A lumped parameter mathematical model to analyze the effects of tachycardia and bradycardia on the cardiovascular system

In this study, the cardiovascular system and heart hemodynamic performance are modeled using lumped method (electrical analogy) to evaluate the effects of abnormal heartbeats on the cardiovascular system performance. Lumped method (voltage-current relations of an electrical circuit) is able to simulate the cardiovascular (CV) system behavior in various physiological conditions. CV system consists of 42 compartments, including artery, vein, capillary set, and heart chambers. Each blood circulatory subsystem (compartment) is modeled using electrical elements, such as resistor, capacitor, and inductor. In this study, by utilizing lumped model, CV system is simulated in matlab software (SIMULINK environment). There are two major types of irregular heart rates. In tachycardia, the heartbeats are too quick: over 100 beats per minute. In bradycardia, the heart beat is too slow: less than 60 beats per minute. Healthy blood circulation and heart performance are modeled (heartbeat: 75 beat/minute), and the results such as left atrium outflow-time graph and pressure-time diagram of aorta artery and pulmonary circulation are obtained. The present results are found to be in agreement with numerical and experimental studies. Then, by increasing and decreasing the heartbeat, the abnormality (150 and 50 beat/minute representing tachycardia and bradycardia, respectively) is simulated. The results show that the tachycardia leads to a significant reduction of capillary blood flow into less than 100ml/s, while it exceeds 100ml/s when heart has normal function. The results of the present study have clinical implications for detailed diagnosis of CV diseases when experimental studies have limitation. Copyright (c) 2014 John Wiley & Sons, Ltd.