Analysis of coronary-sinus-occlusion pressure by iterating the convolution integral.
Intermittent coronary sinus occlusion (ICSO) has been shown to reduce infarct size and to improve regional myocardial function. Since the efficiency of the procedure is closely related to proper intervals of occlusion and release of the coronary sinus, the reactions of coronary haemodynamics to this intervention have to be investigated. Coronary sinus pressure measurements obtained from anaesthetized dogs are analysed for three different conditions: normal coronary perfusion, experimentally induced infarction of the LAD performed according to a specific time pattern. The mathematical modelling of the coronary sinus pressure (CSP) reaction upon ICSO is accomplished by a convolution integral, incorporating a memory function g(x). With the aid of a numerical technique this function is evaluated to reproduce the measured data as closely as possible. Since g(x) describes the CSP response in a universal manner it can serve subsequently to predict reactions to different occlusion and release patterns not actually measured. This use of a mathematical model may provide economical paths for future investigations by avoiding prohibitively large numbers of animal studies. For different physiological states; normal perfusion, infarction and reperfusion; we obtained different memory functions. These differences in g(x) are then shown to be precisely related to known characteristics of the normal and diseased state of the myocardium. Understanding the link between cardiovascular physiology and its mathematical representation is seen as an important aid in the selection of therapeutic interventions.
D000818:Animals; D003326:Coronary Circulation; D003327:Coronary Disease / Q000503:physiopathology / Q000628:therapy*; D004285:Dogs; D006439:Hemodynamics; D008954:Models, Biological; D009203:Myocardial Infarction / Q000503:physiopathology; D010477:Perfusion; D011312:Pressure; D013997:Time Factors