A model of the coronary epicardial tree and intramyocardial circulation in normal and ischemic hearts

A dynamic electrical analog RC model describing the coronary circulation was developed to relate the epicardial flow to the corresponding regional perfusion. The model is based on the aortic driving pressure, the left ventricular pressure, the dominant anatomy, and the geometry (length, diameter) of the epicardial coronary arteries. The myocardial zone supplied by each artery is represented as three compartmental resistances and two capacitances, changing with time as a function of transmural pressure. The intramyocardial pressure affects the circulation by means of the myocardial capacitances. The system has the ability to autoregulate in response to increased flow demand or severe stenosis. This model is also capable of accounting for fixed or dynamic stenoses in the epicardial arterial segments, and the corresponding collaterals which may be added as a function of time and stenosis severity. Pressures and flow rates at each arterial segment and myocardial compartment are calculated.