Responses of blood flow, oxygen consumption, and contractile function to inotropic stimulation in stunned canine myocardium

摘要: Abstract To examine the effects of inotropic stimulation on regional myocardial blood flow (MBF), oxidative metabolism, and contractile function in stunned myocardium, nine closed-chest dogs were studied 2 hours postreperfusion after a 25 minute occlusion left anterior descending coronary artery (LAD). MBF was determined with microspheres, oxygen consumption (MVO2) estimated from rate constant k1 rapid clearance phase [1-11C] acetate time activity curves, recorded dynamic positron emission tomography. Myocardium at risk [13N] ammonia images obtained during occlusion. Wall motion, assessed by two-dimensional echocardiography, impaired postischemic myocardium all reperfusion. Dobutamine infusion increased pressure product 70% ± 31% significantly improved region dogs. In remote MVO2 5.7 1.2 to 8.6 1.6 μmol/gm/min, 0.87 0.16 1.52 0.42 ml/gm/min response dobutamine. reperfused 3.1 0.7 7.4 1.5 0.51 0.12 0.4 ml/gm/min. Oxygen extraction relative consistent flow-limited dobutamine stimulation. The improvement failed correlate increases or MVO2, suggesting that mechanical is not as tightly coupled