A Framework for Simulating Coupling Between Coronary Artery and Myocardial Perfusion: A Preliminary Study

The strong association between cardiac perfusion and myocardial electromechanical deformation motivates this study. We present a numerical model of myocardial perfusion using a Darcy porous media flow in an idealized domain. Our model incorporates cardiac electrophysiology, passive and active mechanics of the myocardium, arterial blood hemodynamics, and a single-compartmental Darcy model to represent microcirculation. We consider a contracting slab domain representing a portion of the myocardium and a cylindrical geometry as the coronary artery. The fluid dynamics in the coronary is governed by the 3-D Navier–Stokes equation, and the myocardium is represented by the porous medium. The coupling of these domains takes place at the interface using appropriate boundary conditions based on the conservation of mass and continuity, where the outlet of the artery supplies flow to the myocardial porous medium. We simulated two clinical conditions: normal and myocardial fibrillation. Results indicated a pressure drop from the coronary to the myocardium of about 44% proving the 46.8 percent local myocardial domain displacement in the normal case than in the fibrillation. There is also a dynamic change in myocardial volume of 10% in a cardiac cycle attributed to the coronary flow and myocardial deformation. Blood is perfused into the myocardium largely when the heart relaxes. The uncoordinated electrical sequence imposed by fibrillation produces more irregular flow in the porous myocardium. These findings offer a basis for a computational framework for investigating coronary–myocardium interaction in a realistic electromechanical-perfusion cardiac model.