The goal of this prospective study is to evaluate the role of cardiovascular magnetic resonance (CMR) in patients with suspected non-ST elevation myocardial infarction (NSTEMI). The main endpoint is the reclassification rate, defined as the number of patients in whom the information provided by pre-angiography CMR affects the revascularization strategy or the final diagnosis.

Participants will undergo to CMR before invasive coronary angiography (ICA).

All patients with NSTEMI eligible for the study undergo CMR prior to ICA. To avoid any delay in patients' treatment all examination will be analyzed by local trained staff at each center. All patients will thereafter undergo ICA and the standard of care (SOC) decision-making on revascularization strategy and diagnosis will be declared by the treating physician, which will be blinded to the participation of the patients in the study and about CMR results. The treating physician will also declare patient's next management according to ICA results. After having declared the diagnosis, the treating physician will then be informed about the CMR findings. Therefore, according to CMR results the treating physician may eventually modify the initial diagnosis and management. Treatment plan modifications include difference in the identification of the culprit lesion, referring the patient to medical therapy instead of a revascularization procedure or viceversa, switching from a percutaneous to a surgical revascularization procedure or viceversa, or need for further cardiac or non-cardiac investigations. Initial diagnosis includes confirmed NSTEMI or all other possible alternative diagnosis and proposed additional diagnostic examination(s) for further differential diagnosis.

The CMR-modified SOC (CMR-SOC) and diagnosis made considering CMR results will be collected.

Inclusion Criteria:

• Age > 18 years old
• Presence of criteria for acute myocardial infarction according to the Fourth Universal Definition of Myocardial Infarction:
• Signs and symptoms of myocardial ischemia
• Detection of acute myocardial injury defined as a rise and/or fall of high-sensitivity cardiac Troponin (hs-cTn) values with at least one value above the 99th percentile Upper Reference Limit at baseline or after presentation.
• Patients scheduled for ICA.
• Written informed consent.

Exclusion Criteria:

• Patients diagnosed with myocardial infarction with ST segment elevation.
• Very High-risk NSTEMI patients according to 2020 ESC Guidelines on Acute Coronary Syndromes:
• Haemodynamic instability
• Cardiogenic shock
• Recurrent/refractory chest pain despite medical treatment
• Life-threatening arrhythmias
• Mechanical complications of MI
• Acute heart failure clearly related to NSTEMI
• ST-segment depression>1mm/6 leads plus ST-segment elevation aVR and/or V1.
• Legally incompetent to provide informed consent
• Participation in another clinical study.
• Regular known contraindications to CMR at time of inclusion such as:
• Severe renal impairment (eGFR < 30 ml / min / 1,73 m2) or on dialysis treatment
• Claustrophobia
• Known pregnancy or breast-feeding patients
• Non MR compatible devices
• Known allergy to Gadolinium

Data will be avaliable under specific request to Principal Investigator