The early intravenous administration of thrombolytic agents in the acute phase of myocardial infarction induces reperfusion of the artery responsible for the necrosis, thereby limiting the size of the infarct and preserving the left ventricular systolic function with consequent reduction of short- or long-term mortality. With the exception of urokinase, these effects have been demonstrated with all thrombolytic agents used so far, including streptokinase, plasminogen tissue activator and anistreplase. Owing to its special pharmacokinetic properties, the latest thrombolytic agent, formerly known as APSAC (anisoylated plasminogen streptokinase activator complex), provides a high arterial reperfusion rate with a low percentage of reocclusion. As a result, the mean size of the infarct is reduced by 31 per cent (36% in the case of anterior infarct), and the left ventricular systolic function is highly significantly preserved.