The purpose of this registry is to depict the myocardial tissue characteristics in NSTEMI patients by CMR and other cardiac imaging modalities and to assess the prognostic value of imaging-derived indices. Information will be collected prospectively in about 2000 NSTEMI patients in 10 sites. Subjects will be followed for up to 5 years.

This is a prospective, multi-center, non-randomized, observational registry study of NSTEMI patients that undergo CMR examination. Information of other cardiac imagings and clinical outcomes are also prospectively collected in the database. This project will establish a prospective registry of 2000 NSTEMI patients in 10 sites with follow-ups of up to 5 years.

The aim of the project will be as following:

1. To investigate myocardial pathological features and functional changes in NSTEMI patients.
2. To identify CMR-derived indices that are associated with adverse clinical outcomes.
3. To compare CMR with other alternative cardiac imaging modalities (i.e., echocardiography or SPECT) on prognostic prediction in NSTEMI patients.
4. To compare myocardial tissue characteristics and functional changes in STEMI (data derived from EARLY-MYO-CMR) and NSTEMI patients.
5. To verify GRACE Score classification in NSTEMI from CMR imaging view.

Inclusion Criteria:

NSTEMI patients who have had CMR imaging performed and have provided written consent.

Patient older than 18 years old with non-ST-segment elevation myocardial infarction (NSTEMI):

1. Ischemic symptoms (chest pain or equivalent) at rest ≥ 10 minutes within 24 hours of randomization,

2. One of the two following criteria:

   1. New ST-segment depression ≥ 0.1 mV (≥1 mm), or transient (< 30 minutes) ST-segment elevation ≥ 0.1 mV (≥ 1 mm) in at least 2 contiguous leads on the electrocardiogram,
   2. Elevation of cardiac biomarkers within 24 hours of randomization, defined as elevated troponin T, troponin I, or CK-MB level above upper limit of normal,

3. Patients who have had CMR imaging performed and have agreed to comply with the follow up requirements.

Exclusion Criteria:

1. Patient who is unable to comply with the follow-up schedule.
2. Patient who has any medical conditions that in the opinion of the investigators will not be appropriate to participate in the study.
3. Patient has a life expectancy of less than 6 months due to any condition.

NSTEMI patients undergo CMR examination are eligible for this registry.