Management of NSTEMI in emergency departements represent 10% of the global activity. Since the the last European Society of Cardiology recommendation the use of an 1 hour rule-in and rule-out protocol is recommended combined with high-sensitivity troponin. But studies show 3% of the patients are false negative using this protocol. This study aims at analysing the feasibility of this protocol in an Emergency Departement and the security of this protocol if combined with a pre-troponin probability score.

Chest pain is a frequent reason for consultation in emergency departments. Among cardiological causes, quickly diagnosing NSTEMI optimize patient treatment. To do this, the European Society of Cardiology, proposed in 2015 an one hour rule-in rule out troponin dosage based protocol. These recommendations should allow a faster diagnosis of NSTEMI but also a rule-out of patients with a low to moderate clinical probability of coronary heart disease. It could also improve efficiency in emergency departements decreasing the length of stay for patient consulting for acute chest pain allowing use of medical and para medical time for other patients. But the studies on which thoserecommendations are based show up to 3% of false negative, which could lead to a higher mortality rate for those patients even if this issue hasn't been address yet. Furthermore, the tight schedule in which a blood sample need to be withdraw, analyzed and taken knowledge of by the doctor could be an obstacle to the feasibility of such protocol in emergency departments usually overwhelmed with patients. The aim of this monocentric prospective study is to assess how a pre-troponin clinical probability of NSTEMI allowing risk stratification could decrease the false negative rate of this protocol insuring safetiness in its use. The secondary objective is to assess the feasibility of such protocol in an emergency department with high patient flow.

Inclusion Criteria:

• Patient with troponin dosage in a suspected NSTEMI.

Exclusion Criteria:

• Under 18 years old
• Respiratory rate over 30 per min
• SpO2 under 92%
• Tachycardia over 110 per min
• Bradycardia under 40 per min
• Fever over 38°5C,
• Anemia under 10 g/dL
• Acute intoxication.

Patients with troponin dosage in a suspected NSTEMI.