Background: Most patients with ST-elevation myocardial infarction fulfilling ST-segment elevation (STE) lytic criteria present an occluded culprit artery but the occlusion rate in those with minimal STE (minSTE) not fulfilling lytic criteria is unknown.
Methods: In 63 patients with minSTE (mean STE:1.2 +/- 0.6 mm) and 149 with lytic STE criteria (lyticSTE, 4.8 +/- 3.1 mm), an emergency coronary angiography was performed, serial creatine kinase-MB was determined, and ejection fraction was measured by 2-dimensional echocardiography.
Results: The 2 groups showed similar time from pain onset to electrocardiogram (minSTE 196 +/- 199 vs lyticSTE, 176 +/- 172 min, P = .444), and although time to catheterization was longer in patients with minSTE (426 +/- 314 vs 253 +/- 239 min, P < .001), the rate of TIMI flow 0 to I (88% vs 81%, P = .21) was similar and percutaneous coronary intervention was performed in >80% of patients from the 2 groups. Moreover, patients with minSTE had higher rate of collateral circulation (27% vs 13%, P = .013), lower rate of Q waves (44% vs 60%, P = .041), lower creatine kinase-MB (202 +/- 150 vs 335 +/- 280, microg/L, P < .001), higher ejection fraction (54% +/- 9% vs 49% +/- 12%, P = .004), and lower mortality (0% vs 7.4%, P = .036).
Conclusions: ST-elevation myocardial infarction patients with minSTE present a high prevalence of TIMI flow 0 to I similar to those meeting lyticSTE suggesting an identical underlying mechanism and the potential to benefit from primary angioplasty.