Acute myocardial infarction may result from rupture or fissuring of atherosclerotic plaque in a coronary artery. Sometimes a different pathogenesis occurs like microembolization following lysis from ulcerated plaque or during pharmacological or interventional procedures. We describe a patient with anterior myocardial infarction treated with alteplase + abciximab (TIMI 14). At the end of thrombolytic therapy administration, we observed a marked reduction of anterior ST elevation associated with a simultaneous occurrence of ST elevation in the inferior leads, later followed by inferior Q waves. The coronary angiogram demonstrated an isolated 60% stenosis on the left anterior descending artery. This case raises the question on whether the very effective and aggressive thrombolytic treatment was paradoxically responsible for microembolization resulting in myocardial infarction extension.