Stratified Medicine of Eplerenone in Acute Myocardial Infarction or Injury and no Obstructive Coronary Arteries.

Inclusion Criteria: * Age ≥18 years. * Acute myocardial infarction or myocardial injury and no obstructive coronary arteries. * Cardiovascular risk factor (≥1): age \>70 years, atrial fibrillation, diabetes, current smoker, eGFR 30 - 60 mL/ minute/1.73 m2, prior MI, treated hypertension or COVID-19 (confirmed or suspected) * Coronary angiography. Exclusion Criteria (trial): * Obstructive coronary artery disease * Left ventricular ejection fraction ≤40% with evidence of heart failure, following myocardial infarction. * Estimated glomerular filtration rate \<30 mL/ minute/1.73 m2 * Severe liver impairment * Women who are pregnant, breast-feeding or of child-bearing potential (WoCBP) without a negative pregnancy test and who are unwilling or unable to follow the reproductive restrictions defined in the eligibility criteria and use highly effective contraception as defined in Appendix 2 for the duration of the study treatment and 30 days after last dose of study drug. * Patients taking one of the following medicines : * Pre-existing treatment with an MRA : * Anti-fungal drugs (ketoconazole or itraconazole). * Antiviral medication (nelfinavir or ritonavir). * Antibiotics (clarithromycin or telithromycin). * Nefazodone used to treat depression. * The combination of an angiotensin converting enzyme (ACE) inhibitor and an angiotensin receptor blocker (ARB)) together. Exclusion Criteria (registry): * Contra-indication to cardiovascular magnetic resonance imaging e.g. severe claustrophobia, metallic foreign body. * Contra-indication to intravenous adenosine, i.e. severe asthma; long QT syndrome; second- or third-degree atrio-ventricular block and sick sinus syndrome. * Lack of informed consent.