虚血心における冠側副循環の機能的役割に関する実験的研究
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概要
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The present study was attempted to investigate the role of the coronary collateral circulation in dogs. In this study, ST elevation in epicardial and intramyocardial electrograms was used to assess the degree of regional myocardial ischemia. 1. After ligation of the anterior descending coronary artery, marked ST elevation more than 2mV was observed in 102 dogs (Group I) in epicardial lead of the area, which had been nourished by the artery. In seven dogs (Group II), however, no significant ST elevation was demonstrated. 2. Systemic hemodynamic parameters showed no statistically significant difference between the two groups, but coronary collateral indices, i.e. retrograde flow and peripheral coronary pressure, were significantly greater in Group II than Group I. 3. Diversion of retrograde flow induced a marked ST elevation in Grop II, but it was improved immediately after restoration of retrograde flow. In Group I, however, no significant ST-segment changes were observed with these procedures. 4. In 6 of 15 dogs with chronic obstruction of the anterior descending coronary artery with Ameroid constrictor, pacing-induced tachycardia resulted in ST elevation in the collateral and the intermediate areas (Group A). In another 9 dogs (Group B), however, pacing-induced tachycardia failed to produce ST elevation in any electrograms, and more than 50% constriction of the donor coronary artery was necessary to produce ST elevation. 5. In stress condition with pacing or pacing plus constriction of the donor coronary artery, ST elevation first appeared in the collateral area together or not with the intermediate area, and spread from the inner layer to the outer layer. 6. Although systemic and coronary hemodynamic parameters were not different between the two groups, coronary collateral indices were significantly greater in Group B than Group A. These results indicate that the coronary collateral circulation in dogs play a beneficial role to prevent the myocardium from ischemic injury not only in resting condition but also in stress condition, and that the preventing capacity depends on the degree of the development of collateral vessels.
- 神戸大学の論文