Investigators propose a study to assess the gastric emptying times at the acute phase of myocardial infarction using a validated paracetamol absorption test. The STEMI group will be compared to in one hand, itself with measures performed 72 hours±12h after the event onset; and on the other hand, to a stable patient group referred for angioplasty for angina or non-ST-segment elevation myocardial infarction (NSTEMI). For STEMI group and stable patient group, the delay of apparition of Prasugrel or Ticagrelor efficacy will be determined by VerifyNow® test and correlated to gastric emptying times.