Effects of Propofol on the Function of Normal, Collateral-Dependent, and Ischemic Myocardium

Abstract

To examine the effects of propofol on the function of normal, collateral-dependent, and acutely ischemic myocardium, nine mongrel dogs were chronically instrumented with hydraulic occluders and ameroid constrictors were inserted around the left coronary artery, pressure transducers in the left ventricle, and heparin-filled catheters in the descending aorta and the left atrium. Regional function of normal, collateral-dependent, and acutely ischemic myocardium was assessed by sonomicrometry. Propofol (5 mg/kg intravenously) reduced function in normal myocardium (-15% +/- 5%, 1 min and -14% +/- 5%, 3 min after injection) and in collateral-dependent myocardium (-14% +/- 5% and -13% +/- 5%) to similar degrees, whereas ischemic myocardial function deteriorated significantly more (-25% +/- 10% and -23% +/- 10%, P < 0.01). Although left ventricular end-diastolic pressure remained unchanged and left ventricular contractility was reduced (-16% +/- 4%, 1 min and -15% +/- 3%, 3 min after propofol, P < 0.01), significant increases in heart rate (35% +/- 7% and 26% +/- 7%, P < 0.01) and decreases in coronary perfusion pressure (-14% +/- 5%, P < 0.05 and -19% +/- 6%, P < 0.01) occurred, likely affecting the function of ischemic myocardium. Thus, whereas collateral-dependent myocardium tolerated these adverse hemodynamic effects, ischemic myocardium responded with impairment of regional function that was significantly more pronounced than the impairment which occurred in normal or collateral-dependent areas after a 5 mg/kg intravenous bolus of propofol.