Research on Infarction With Open Arteries Using OCT and CMR

Inclusion Criteria: * Acute ischemic symptoms compatible with diagnosis of acute coronary syndrome (ACS) (chest pain or anginal equivalent symptoms at rest or new onset exertional anginal equivalent symptoms) * Objective evidence of myocardial infarction (either or both of the following): Elevation of troponin to above the laboratory upper limit of normal (ULN) or ST segment elevation of ≥1mm on 2 contiguous ECG leads * Willing to provide informed consent and comply with all aspects of the protocol * Age ≥ 21 years Exclusion Criteria: * Stenosis ≥50% of any major epicardial vessel on invasive angiography, as determined by the angiographer at the time of clinically ordered cardiac cath. * History of known obstructive CAD at angiography, including history of percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) * Recent use of vasospastic agents, such as cocaine, triptans, ergot alkaloids (≤1 month) * Alternate explanation for troponin elevation, such as hypertensive urgency, acute exacerbation of heart failure, chronic elevation due to kidney disease, pulmonary embolism, cardiac trauma * Coronary dissection apparent on angiography * Excessive coronary tortuosity which, in the opinion of the angiographer, increases the risks of OCT * eGFR\<30 or contraindication to additional contrast needed for OCT in the opinion of the angiographer or treating physician * Contraindication to MRI (including but not limited to MRI-incompatible metal implants or foreign bodies) * Pregnancy * Thrombolytic therapy for STEMI (qualifying event)