Thrombolytic Therapy Within One Hour of the Onset of Acute Myocardial Infarction

Between 1986 and 1988, 239 consecutive patients with acute myocardial infarction received thrombolytic therapy up to 285 minutes after onset of symptoms; in 39 (17 with anterior infarction, 21 inferior, one lateral infarction) recombinant tissue plasminogen activator or anistreplase was administered a mean of 51 minutes (range 20–60 minutes) after the onset of symptoms. The patency rates (26 of 30; 87 per cent), rapid ST segment resolution (36 of 38; 95 per cent) and QRS score of ≤3 (28 of 38; 74 per cent) were statistically significantly higher for those seen and treated in the first hour in comparison with those seen and treated later. For those treated within the first hour mean peak creatine kinase was 1264 U/I for those with TIMI grade 2 or 3 (partial or complete perfusion) compared with 3005 U/I for those with TIMI grade 0 or 1 (no perfusion or penetration without perfusion) (p</it>=0.02): mean peak creatine kinase-MB for those with TIMI grade 2 or 3 perfusion was 115 U/I compared with 312 U/I for those with TIMI grade 0 or 1 (p</it>=0.01). Four of the 39 patients developed ventricular fibrillation following thrombolytic therapy, three within 24 hours of infarction and one following reinfarction on day 15. There were no significant bleeding complications. One patient died. Thrombolytic therapy within 1 hour of the onset of symptoms led to a very high angiographic patency rate, rapid ST segment resolution with preservation of left ventricular function. This therapy is without significant complications.