The authors report the cases of two men, 62 and 66 years-old, who both presented a posterolateral myocardial infarction which, in the first two days, as only electrocardiographic sign, consisted in a baseline offset of the ST segment in precordial leads V2 to V4. Necrosis and its topography were confirmed in each case by elevated myocardial enzymes, the progression of the electrocardiogram and bidimensional ultrasound cardiography exploration. Coronary angiography performed in both cases, revealed, in the first case, an isolated narrow stenosis of a first marginal artery, and in the second case, significant stenoses of the circumflex and right coronary artery without lesion of the anterior interventricular artery. These cases, along with those recently published in the literature, suggest that such alterations of ventricular repolarization which represent the reciprocal projection of a high posterior sub-epicardiac lesion current, could complete the electrocardiographic criteria of really thrombolysis in a context of prolonged precordial pain.