In Ireland, to date, coronary thrombolytic therapy has been confined almost exclusively to the use of streptokinase. However, a large body of evidence suggests that, in comparison to streptokinase, the agent recombinant tissue-type plasminogen activator (rt-PA) may be more effective in lysing coronary thrombi and achieving coronary reperfusion and causes fewer disturbances of the coagulation system. With these considerations in mind, we undertook a study to explore the future potential role of rt-PA in our particular clinical practice. Sixteen patients presenting to our centre with clinical and ECG features suggestive of acute myocardial infarction were treated with rt-PA and heparin infusion within 3.8 +/- 1.3 (mean +/- SD) [range 0.6 - 5.3] hours of the onset of their symptoms. Reperfusion, as assessed by clinical, electrocardiographic and biochemical criteria, was achieved in 15 of these 16 patients. One patient developed reocclusion that was successfully treated with repeat thrombolytic therapy. Follow up coronary angiography, performed in eight patients, confirmed successful reperfusion in seven. One patient developed an intracranial haemorrhage. The result of this pilot study highlight the importance of considering thrombolytic therapy in all patients presenting with suspected acute myocardial infarction (AMI). Our observations also suggest that rt-PA is very effective in restoring myocardial perfusion in patients with AMI who present at an early stage. As with all thrombolytic agents, it may be associated with haemorrhagic complications. Determination of the precise role of rt-PA, as opposed to other thrombolytic agents, awaits the results of ongoing clinical trials.