Effect of sodium salicylate and acetylsalicylic acid on epicardial ST-segment elevation during coronary artery occlusion in dogs

The effect of sodium salicylate and acetylsalicylic acid (ASA) on myocardial ischaemic injury following acute coronary artery occlusion has been studied in thoracotomized dogs during basal conditions and during elevation of plasma free fatty acid (FFA) concentration induced by intravenous (i.v.) infusion of isoprenaline (0.075-0.15 microgram/kg/min). Ischaemic injury was measured as the sum of ST-segment elevations (sigmaST) in epicardial ECG recordings from 10-15 sites 15 min after occlusion. Both sodium salicylate and ASA (60 mg/kg) significantly reduced sigmaST both before and during isoprenaline infusion. Arterial concentrations of FFA were reduced by either drug during isoprenaline infusion, whereas in the basal state only a significant effect by sodium salicylate could be demonstrated. The reduction in epicardial ST-segment elevation during coronary occlusion could not be explained by reduced mechanical activity of the heart. It is suggested that the reduction by salicylates of myocardial ischaemic injury might be related to reduced utilization of FFA by the myocardium, although a FFA-nondependent mechanism cannot be excluded in the basal state.