[Intramyocardial pressure at various depths, during aortic constriction and myocardial ischemia in the dog (author's transl)].

Systolic intramyocardial pressure (IMP) is measured with a modification of the "closed perfusion technic" in 3 different layers of the myocardium in 8 anesthetized mongrel dogs. In the subendocardium IMP exceed left ventricular pressure (LVP) by about 30% whereas it is 30% lower than LVP in the subepicardium. Under resting conditions the level of isobaric balance of IMP and LVP is at a distance of 57% from the epicardium. During thoracic aortic constriction the ratio of IMP/LVP increases in the subepicardium but decreases in the subendocardium. Occlusion of the left circumflex coronary artery for 30 seconds results in a decrease of IMP and IMP/LVP in the ischemic region. In 25% of all cases, however, an increase of these parameters is found.