Subendocardial S-T segment changes during acute coronary occlusion.
Subendocardial ischemia during coronary occlusion in dogs was studied using S-T segment elevations in unipolar subendocardial electrodes. Alterations in heart rate or cardiac output caused quantitatively similar changes in subendocardial and epicardial S-T elevation. Increasing blood pressure from 75 to 100 or 75 to 125 mm Hg caused a smaller reduction in subendocardial than in epicardial S-T elevation (p less than 0.01). In this situation, therefore, subendocardial ischemia tends to be maintained while epicardial ischemia is reduced by higher arterial pressures. Hemodynamic manipulations can cause quantitatively different changes in subendocardial and epicardial S-T segment elevation.
D000818:Animals; D004285:Dogs; D004562:Electrocardiography / Q000295:instrumentation; D004699:Endocardium / Q000503:physiopathology; D006324:Heart Arrest, Induced; D006329:Heart Conduction System / Q000503:physiopathology; D007431:Intraoperative Complications / Q000503:physiopathology*; D009203:Myocardial Infarction / Q000503:physiopathology*; D009206:Myocardium / Q000378:metabolism; D010101:Oxygen Consumption / Q000502:physiology