Oral antiplatelet therapy is a key treatment of the STEMI (ST elevation myocardial infarction). Delayed action isn't suitable and has to be elucidated. If a delayed gastric emptying time is observed during STEMI, limiting the use of morphine and encourage the use of prokinetic agents can be a first answer to optimize coronary angioplasty environment.

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.

Oral antiplatelet therapy is a key treatment of the STEMI (ST elevation myocardial infarction). Delayed action isn't suitable and has to be elucidated. If a delayed gastric emptying time is observed during STEMI, limiting the use of morphine and encourage the use of prokinetic agents can be a first answer to optimize coronary angioplasty environment.

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.

Paracetamol absorption test is a safe, cheap and well validated method to assess these times including during the STEMI period. This one consists in oral ingestion of 1.5g of paracetamol followed by the realization of the curve of concentration of paracetamol in plasma samples. These samples are taken at 15 min intervals during the first 2 hours.

In the same time the curve of Platelet reactivity Unit (PRU) obtained by VerifyNow® tests will be determined with the goal to establish a relation between gastric emptying times and delayed observed antiplatelet activity.

Inclusion Criteria:

• Patient over 18 years weighing between 65 and 85 Kg
• Referred for STEMI within 6 hours from beginning of chest pain or stable coronary artery disease requiring a loading dose of Prasugrel or Ticagrelor according to the international recommendations.
• No previous treatment with Clopidogrel, Prasugrel or Ticagrelor.
• Patient fasting for at least 6 hours.
• Affiliate or receiving a social security system.
• Written informed consent.

Exclusion Criteria:

• Allergy or contraindication to paracetamol, Prasugrel or Ticagrelor
• Paracetamol ingestion in the previous 48 hours
• Patient treated with drugs supposed to alter gastric emptying times (calcium antagonists, Alimentary tract treatments, opioid analgesics, tricyclic antidepressants, antibiotics).
• Conditions or pathologies supposed to alter gastric emptying times (Thyroid dysfunction, chronic renal failure, Parkinson's disease, scleroderma, amyloidosis, any gastrointestinal disease, any not cured malignancy, and any advanced psychiatric or neurological disease).
• Presence of vomiting
• Cardiogenic shock, ventricular arrhythmia or resuscitated cardiac arrest
• Hepatic insufficiency
• Severe respiratory disease
• Pregnant or breastfeeding women