Concern has been expressed that delays in physician and cath lab mobilization may adversely affect the feasibility and outcome of a primary angioplasty strategy in pts with acute MI presenting in the early morning hours. In the PAMI Trial, 395 pts within 12 hours onset of MI were prospectively randomized to t-PA (n = 200) vs. primary PTCA (n = 195). Demographic characteristics were similar between pts presenting between 12 MN and 6 AM (Group A) and 6 AM to 12 MN (Group B). Outcomes appear below: Time (mins) PTCA t-PA Group A (n = 36) Group B (n = 159) Group A In = 38) Group B (n = 162) chest pain onset to randomization 211 ± 129 173 ± 116 * 258 ± 179 183 ± 139 † randomization to t-PA bolus N/A N/A 34 ± 25 31 ± 22 randomization to cath lab arrival 43 ± 20 39 ± 18 N/A N/A cath lab arrival to first angiogram 21 ± 9 20 ± 11 N/A N/A first angiogram to reperfusion 19 ± 14 20 ± 24 N/A N/A Hospital events PTCA success 91.7% 94.3% N/A N/A Death 5.6% 1,9% 7,9% 6.2% Death or reinfarction 13.4% 3.1% § 18.4% 105% £ Recurrent ischemia 16.7% 88% £ 34.2% 26.5% * p l 0.09 † P = 0.005 § p = 0.008 £ p l 0.18 All other p = NS Conclusions Time to presentation is prolonged in pts with MI in the early morning hours. No delays occur, however, in cath lab mobilization, PTCA performance or success. Further studies are required to explain the apparently worse prognosis of pts presenting between 12 MN and 6AM in this trial.