HROMBOLYTIC THERAPY for acute myocardial infarction (MI) now represents the standard of care for many patients. A large number of clinical trials have demonstrated improvement in survival and cardiac function following treatment of acute MI with thrombolytic agents,‘.’ and the use of thrombolytic therapy is rapidly spreading to community hospitals. A number of clinical trials are focused on expanding the eligibility criteria for thrombolytic therapy to groups excluded from initial studies. The consequent widespread use of thrombolytic therapy will necessitate an understanding of the comphcations of this therapy and a strategy for their management. The major complications are failure of initial coronary reperfusion, coronary reocclusion, and hemorrhage. This article will review the fibrinolytic system and then examine the use of laboratory and noninvasive cardiac monitoring of clinical outcome following fibrinolytic therapy.