[Effect of enflurane on the function of the chronically ischemic myocardium]

The effects of enflurane on the function of the chronically ischemic myocardium were studied in nine dogs, 2-8 weeks after implantation of Doppler-ultrasound flow transducers around the circumflex branch of the left coronary artery, of pairs of ultrasonic crystals in normal and ischemic regions of the left ventricle, aortic catheters, and of solid-state left ventricular pressure gauges. Enflurane (2% and 4% inspired) caused an increase in heart rate and dose-dependent decreases in left ventricular pressure, dP/dt, mean arterial pressure and mean circumflex coronary resistance. However, in comparison to the normal myocardium neither exaggerated nor permanent dysfunction of the chronically ischemic but still contracting myocardium was noted. Thus, reduction of coronary perfusion pressure and coronary vasodilatation does not seem to be of major functional significance in determining ischemic left ventricular performance during anesthesia with enflurane.