This study is to validate 1-hour and 3-hours diagnostic strategy using Architect high-sensitivity cardiac troponin I (hs-cTnI) in Chinese patients with suspected Non-ST-elevation Myocardial Infarction (NSTEMI). The accuracy of 1-hour and 3-hours algorithm of NSTEMI using hs-cTnI assays will be evaluated in China emergency patients. This trail is going to determine the optimal diagnostic cut-off value of NSTEMI in Chinese population according to 24-hour or longer clinical diagnosis of MI in routine way.

Cardiac Troponin is recommended as a preferred cardiac biomarker in third universal definition of myocardial infraction. The validated high-sensitive cardiac troponin I is also considered competent 1-hour algorithm to rule out and/ rule in NSTEMI in 2015 ESC Guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation. However, the diagnostic threshold of 1-hour and 3-hour need more solid evidence in Chinese population. This study is to validate 1-hour and 3-hours diagnostic strategy using Architect high-sensitivity cardiac troponin I (hs-cTnI) in Chinese patients with suspected non-ST-elevation Myocardial Infarction (NSTEMI). The accuracy of 1-hour and 3-hours algorithm of NSTEMI using Architect hs-cTnI assays will be assessment in China emergency patients. This trail is going to determine the optimal diagnostic cut-off value of NSTEMI in Chinese population according to 24-hour or even longer clinical diagnosis of MI in routine way.

In primary phase of the present study, 400 patients with acute chest pain, who suspected NSTE-ACS, will be enrolled when visiting emergency department of Fuwai hospital. In subsequent study, multi center emergency department in China plan to recruit 2000 patients suspected NSTE-ACS. The inclusion and exclusion criteria had been described in the following eligibility part. All recruited patients undergo an initial clinical assessment including clinical history, physical examination, 12-lead ECG monitoring, routine blood measurements and echocardiogram. The blood samples of patients will be collected according to standard biobank protocol. Cardiac troponin I, CK-MB and myoglobin will be measured at presentation, 1-hour, 3-hours and 12-hours employing contemporary cTnI and high-sensitive cTnI, respectively.

The diagnosis of each enrolled patient will be made according to routine clinical approach and 1-hour and 3-hours clinical approach, respectively. The routine clinical diagnosis will be made by cardiologist panel according to third universal definition of myocardial infraction through reviewing all available medical records. The NSTEMI diagnosis depended on Architect hs-cTnI assessment will be made a senior cardiologist according to 1-hour and 3-hours clinical approach recommended by 2015 ESC guidelines for the management of NSTEMI. When there was disagreement about the diagnosis, cases were reviewed and adjudicated in conjunction with a third senior cardiologist.

Finally, statistical expert will evaluate the diagnostic performance of 1-hour and 3-hours clinical approach and diagnostic threshold of NSTEMI when the new hs-cTnI employed.

Inclusion Criteria:

• 18-75y;
• highly suspected NSTEMI;
• ECG results without ST-segment elevation;
• without new Left bundle branch block (LBBB) ;

Exclusion Criteria:

• STEMI;
• underwent major surgical operation or injury within four weeks;
• medium and several kidney dysfunction (Ccr<30ml/min);
• anemia(Hb<90g/L);
• acute myocarditis;
• chronic cardiac dysfunction (NYHA III-IV);
• serious cardiac arrhythmias;
• Have had similar symptoms and treatment with thrombolysis before one month;
• history of intravenous drug;
• history of oncosis;
• pregnant;
• even recruited;

In primary phase of the present study, 400 patients with acute chest pain, who suspected NSTEMI, will be enrolled when visiting emergency department of Fuwai hospital. In subsequent study, multi center emergency department in China plan to recruit 2000 patients suspected NSTEMI. Patients aged 18-75 years old and highly suspected NSTEMI without Left bundle branch block (LBBB) will be included. Patients will be excluded if who is STEMI, underwent surgical operation within four weeks, medium and several kidney dysfunction (Ccr<30ml/min), anemia, acute myocarditis, chronic cardiac dysfunction (NYHA III-IV), serious cardiac arrhythmias, with history of intravenous drug, oncosis and recent thrombolysis treatment, or pregnant.