[Change in the width of the preischemic and late myocardial zones]. / Izmenenie shiriny priishemicheskoi i otdalennoi zon miokarda.

A new approach to the determination of the boundaries of the preischemic zone and zones compensating for the focal disorders of the contractile activity of the hepart is described. During 30 minutes of inschemia, the width, localization, and intensity of functioning of the borderline and compensation zones changed. On the 15th minute of disturbed coronary blood flow the compensation zone was widest. It consists of 4-5 adjacent myocardial areas with increased active shortening of the heart muscle. The width of the borderline zone is greatest on the 10th and 25th minutes. Myocardial areas located on the boundary of the zones may alter their condition and be now functionally borderline, now functionally remote.

[Presystolic change in the length of the ischemic, border and distant myocardial areas in experimental coronary insufficiency and the action of inderal and metacin]. / Presistolocheskoe izmenenie dliny ishemicheskikh, pogranichnykh i otdalennykh uchastkov miokarda pri éksperimental'noi koronarnoi nedostatochnosti i deistvii inderala i metatsina.

Changes in the presystolic length in the phase of late diastole and in the size of active shortening in the phase of ejection were determined in the ischemic area and in areas of the myocardium bordering upon and in those remote from the focus of ischemia in acute experiments on the 20th and 60th seconds of reversible clamping of the coronary artery. Marked increase in the presystolic length and size of active shortening of the remote areas was noted by the 20th second. In the ischemic zone these values decreased. Due to the effect of a therapeutic dose of inderal, the intensifying reaction of the remote areas diminished markedly and the unfavourable effect of ischemia on the stretching and shortening functions of the ischemic zone became somewhat weaker. Metacin caused no such effect.

[Comparison of the blood plasma depressor prostaglandin content and the indicators of hemodynamics in dogs with experimental myocardial infarct and cardiogenic shock]. / Sopostavlenie soderzhaniia depressornykh prostaglandinov v plazme krovi i pokazatelei gemodinamiki u sobak s eksperimental'nym infarktom miokarda i kardiogennym shokom.

The quantitative composition of depressor prostaglandins PGE1 and PGA1 in the plasma of arterial and venous blood and blood from the great cardiac vein was studied in comparison with the values of hemodynamics in dogs with experimental myocardial infarction and cardiogenic shock. The content of prostaglandins in blood plasma was determined by the radioimmune method. The development of acute coronary insufficiency was attended with changes in the quantitative composition of the depressor PGE1 and PGA1 in the plasma of arterial and venous blood and blood from the great cardiac vein. In myocardial infarction and particularly in cardiogenic shock, intensification of PGE1 and PGA1 synthesis and an increase in the consumption of these PG by the myocardium occurred beginning with the first hours following occlusion of the coronary arteries, which suggests that PGE1 and PGA1 may probably take part in the normalization of the activity of the affected heart.

[Effect of strophanthin on the metabolism, electrolyte content, myocardial ultrastructure and contractile function of the heart in the peri-infarction zones in experimental infarct]. / Vliianie strofantina na metabolizm, soderzhanie élektrolitov, ul'trastrukturu miokarda i sokratitel'nuiu funktsiiu serdtsa v okoloinfarktnykh zonakh pri éksperimental'nom infarkte

The results of a complex study are presented dealing with the effect of Strophantin on metabolism, electrolytes content, myocardial ultrastructure and contractile function of various portions of the heart in dogs with experimentally induced infarction. Under the effect of Strophantin the destructive alterations of the myocardial ultrastructure, the electrolytes shifts and disorders in the contractile function of the myocardium in the zone of impaired circulation (25 min.) were less severe than in non-treated dogs. A more distinct beneficial effect of Strophantin upon the structural-functional state of the myocardium was revealed in the parainfarction zones after 2 days and 2 weeks following the ligation of the coronary artery. A reduction of potassium and sodium content in the paranecrotic zone of the myocardium in early postinfarction periods in treated animals must be largely due to the more active ion diffusion in this zone of the infarction caused by improved microcirculation.