Myocardial mechanics and coronary flow dynamics.

The interaction between cardiac mechanics and coronary flow is highlighted here. Left ventricular (LV) structure and geometry are related to coronary flow dynamics and used in the analysis of experimental coronary flow data. The important role of the collagen mesh in the generation of the intramyocardial pressure (IMP), the pressure in the interstitial fluid, at a wide range of loading conditions is emphasized. The calculated IMP, based on a structural model of the LV myocardium, can explain most of the observed coronary compression characteristics under a variety of loading and contractility conditions. A more general compression function, the extravascular compressive pressure (ECP), is suggested to define coronary compression and is presented here based on the dynamics of the coronary inflow under constant perfusion conditions. Coronary compression is shown to be affected by fluid transport and the bi-directional coupling of coronary hemodynamics and IMP dynamics.