An early, complete, and sustained patency of the infarct related artery achieved by thrombolytic therapy reduces mortality in patients with acute myocardial infarction. In the ISIS-3-study there was no difference in mortality between t-PA, APSAC, and streptokinase. In contrast, in the GUSTO-trial, a "front-loaded" regimen of t-PA (100 mg/90 min) lead to a reduced inhospital mortality compared to streptokinase. This was most likely due to the higher early patency-rate of the infarct-related artery after the front-loaded t-PA. The search for new, more effective, thrombolytic regimens lead to a double-bolus injection of t-PA (2 x 50 mg) which revealed high early patency rates (> 80% TIMI-3 after 90 min). R-PA, a new recombinant plasminogen activator with a prolonged half-life, given as double bolus (2 x 10 MU), also produced high patency rates after 90 min without an increased incidence of reocclusions. Acetylsalicylic acid should be given routinely in every thrombolytic therapy. An anticoagulation with heparin seems to improve the efficacy of the more fibrin-specific thrombolytics t-PA, r-PA, and pro-urokinase. In dose-finding studies the specific thrombin inhibitor hirudin has been shown to significantly reduce reocclusions and reinfarctions compared to heparin. An "optimal thrombolysis" most likely can only be achieved by a thrombolytic agent with a very high early patency combined with an effective adjunctive therapy with platelet aggregation- and thrombin-inhibition.