MECHANICAL DETERMINANTS OF MYOCARDIAL PERFUSION

Both, the phasic patterns of coronary arterial and venous flow and the time averaged coronary blood flow are strongly influenced by cardiac contraction. The effect is most pronounced at the subendocardium. The time varying stress in the ventricular wall seems to be the most important factor for these effects. However, left ventricular pressure is transmitted into the myocardial wall but its effect is strongest when the wall stresses are low. Left ventricular pressure may be a very important factor when by coronary artery disease a part of myocardium is underperfused. There left ventricular pressure may contribute considerably to the impeding effect. The interactions between arterial pressure as perfusion pressure and force of contraction as impeding pressure are best described by intramyocardial pump models. Although much work in this direction has been done a satisfactory model for the description of mechanical determinants of coronary flow is still lacking. © 1995 Steinkopff Verlag.