Laser Atherectomy for ST Elevation Myocardial Infarction

Inclusion Criteria: * Patients to whom PCI treatment for anterior STEMI is indicated \[Main selection criteria\] * First-episode anterior STEMI patients within 6 hours of onset that satisfy electrocardiogram criteria * Patients who are 21 years of age or older at the time of consent acquisition * Patient who the patient himself agreed in writing Exclusion Criteria: * Patients presenting cardiac shock at the time of visit * Patients whose target lesions are left main trunk, circumflex, right coronary artery, distal anterior descending branch * Patients who have TIMI 2, 3 at the initial imaging * Patients with a reference vessel diameter of 2.5 mm or less * Patients determined to lack consent ability for mental or other reasons * Patient who is judged inappropriate by research researcher or research sharing doctor The inclusion and exclusion criteria for the MRI will follow the main study, but in addition, will exclude following conditions. * Atrial fibrillation subject at the timing of MRI scan * Internally implanted devices such as pacemakers or ICDs * Subject that is allergic to Gadolinium, * Subject with claustrophobia * Pregnancy