Inhibition of Late Sodium Current (INa) to Prevent Coronary MICROvascular Dysfunction in Patients Presenting With ST-Elevation Myocardial Infarction and Multivessel Disease: INaMICRON Study

Inclusion Criteria 1. Age ≥ 18 years and \< 80 years on day of signing informed consent 2. Ability to provide written informed consent in a time window 0 to 1 day after successful pPCI 3. ST-Elevation Myocardial Infarction at the time of the index hospitalization. 4. Successful pPCI (Thrombolysis In Myocardial Infarction \[TIMI\] flow 3 and residual coronary stenosis \<30%) 5. Presence of at least one remaining angiographically significant (% diameter stenosis \> 50%) non-culprit stenosis treatable with PCI 6. Evidence of post-menopausal status or negative urinary or serum pregnancy test for child-bearing potential patients (definitions reported in section 10.9) 7. Agreement for child-bearing potential patients who are sexually active to use contraception (definitions reported in section 10.10) Exclusion Criteria: 1. Hemodynamically unstable patients 2. Previous myocardial infarction 3. Previous coronary artery by-pass graft (CABG) 4. Female patients with a positive pregnancy test at enrollment or prior to administration of study medication. 5. Female patients who are pregnant or breastfeeding or reproductive potential who are not willing to employ effective birth control from screening to 90 days after the last dose of Ranolazine 6. Known hypersensitivity to the active principle (Ranolazine) or any of the excipients 7. Chronic Kidney Disease Stage 4 or 5 (eGFR \< 30 mL/min/1.73 m 2) 8. Moderate to severe liver failure (Child Pugh B - C) 9. Simultaneous intake of the following classes of drugs: strong CYP3A4 inhibitors (i.e. clarithromycin, erythromycin, diltiazem, itraconazole, ketoconazole); HIV protease inhibitors (i.e. saquinavir, indinavir, ritonavir); class Ia antiarrhythmic drugs (i.e. ajmaline, disopyramide, procainamide, quinidine ) and class III antiarrhythmic drugs except amiodarone (i.e. dofetilide, sotalol) 10. Previous participation in a clinical trial in which an investigational drug was administered within 30 days of screening or within the 5 half-lives of the study drug, whichever is longer.