Abstract: Objective:To dosewe the effect of thrombolytic reperfusion on QTc and QTd.Methods:37 patients with AMI are tested.These patients with QTc440ms are 41% and those ones with QTd50ms are 57% in this group. Thrombolytic patency patients are 17 and that no-patency ones 20 after giving them a dose of intravenous 1 0～1 5×106 uurokinase.Results:Two weeks later,QTc is shorter in thrombolysis with patency group (QTc max 361 28ms) than in that with non-pateney group (QTc 417 32ms),There is an obvious QTd difference between patency group and non-patency group.Conclusion:A successful thrombolytic treatment chiefly acts on myocardial repolarization to shorter QTc and QTd,so QTd can be an independent parameter to judge prognosis.