[Relation between the contractile activity of the heart and coronary circulation in different functional states of the myocardium].

The character of interrelationship among changes of the myocardium function, its need in blood supply and the coronary blood flow was studied in the dog isolated heart on graded increases of the left ventricle load. High perfusion pressure (PP)--13.3 kPa--made possible an adequate perfusion of the myocardium in one series of the experiments; in the second series, coronary dilatory capacity was greatly limited (PP=7.9 kPa), and in the third series coronary blood flow was significantly reduced (PP=6.0 +/- 0.25 kPa). Straight linear interrelationship only existed within the physiological range of the myocardium function and was combined with efficient left ventricle performance and adequacy of its blood supply. Overloading of the left ventricle as well as limiting of coronary dilatory capacity or coronary blood flow distorted the interrelationship, and myocardial need in blood supply greatly exceeded the actual coronary blood flow.