Widespread interest in the benefits of early thrombolysis has resulted from the very positive results of sever¬al large trials that have strongly fa¬voured the use of intravenous throm¬bolysis in patients during the early phases of acute myocardial infarction. Nontheless., sometimes early restitu¬tion of blood flow leaves the "Stunned" myocardium in a state of depressed haemodynamic function (Braunwald and kloner, 1982). Many research workers have long been im¬pressed by the finding that restitution of coronary blood flow to the ischemic myocardium may precipitate a series of events that would either have oc¬curred later or not at all (Nayler and Eiz, 1986). Possible manifestations of reperfusion vary from acute transitory events such as arrhythmia to all nec¬rosis (Jennings et al., 1986). The du¬ration of ischemia markedly influenc¬es the severity of metabolic injury in the reperfusion period (Ferrari et al, 1986). The aim of this work was to try to detect the best time for reperfusion of the ischemic myocarduim.
MATERIAL AND METHODS
The present study was conducted on adult sprague dawely rats of both sexes, weighing 250 - 300 gm. The rats were fed on a standard laboratory diet. The rats were food prohibited 3 hours before the study. Anaesthesia was done following the method of lwamto et al., (1987).The animals were fixed on an operation table. Electrocardiographic electrodes were connected to upper and lower limbs by subcutaneous needles. Lead 2 was recorded as it is more informative