Over a 2-year period 192 patients with acute myocardial infarction (AMI) were transported by helicopter and treated with recombinant tissue-plasminogen activator (tPA). All patients were entered into the Thrombolysis in Myocardial Infarction-Phase II (TIMI II) trial. Eighty-two of these patients were treated with tPA after aeromedical transport to a tertiary care center. One hundred ten patients had tPA treatment initiated by the flight crew prior to transport. The flight crews initiated therapy 28 +/- 11 minutes after arrival at the sending hospital. The post-flight treated patients received the tPA bolus 82 +/- 20 minutes after arrival at the sending hospital (P less than .0001), and 41 +/- 18 minutes after arrival at the receiving hospital (P less than .0001). Based on enzyme and electrocardiographic changes, all patients in the study had a confirmed diagnosis of AMI before discharge. Patients with inferior myocardial infarction (MI) treated with tPA in-flight were more likely to suffer from bradycardia and hypotension requiring atropine injection during transport than the post-flight treated patients or in-flight treated patients with anterior MI. There was no in-flight mortality in either group. Our experience indicates that patients with AMI can be transported safely during tPA therapy. Also, a trained team whose sole responsibility is the early evaluation and initiation of therapy in a patient with AMI can function as accurately and significantly more rapidly than tertiary care emergency department and ICU personnel following identical protocols.