Snapshot A 60-year-old man presents to the emergency department due to substernal chest pain. He describes the pain as "crushing" and it radiates down the left arm. Medical history is significant for hypertension and hypercholesterolemia. On physical exam the patient is diaphoretic. An electrocardiogram demonstrates ST-segment elevations and cardiac troponins are significantly elevated. After appropriate acute therapy, the coronary catheterization lab is activated and cardiology is consulted. Introduction Clinical definition login to view 2 more bullets Types login to view 10 more bullets Epidemiology Incidence login to view 1 more bullet Risk factors login to view 16 more bullets Etiology Occlusion of a coronary artery can be caused by login to view 7 more bullets Pathophysiology login to view 12 more bullets ECG Changes and STEMI ECG Changes and STEMIInfarction LocationInvolved ECG LeadsInvolved Coronary ArteryInferior wallII, III, and aVFRCAAntero-apicalV3 and V4LAD (distal)Antero-septalV1 and V2LADAntero-lateralV5 and V6LAD or LCXLateralI and aVLLCXPosteriorST depression and tall R waves that can be seen anywhere in V2-5 (not all leads mandatory)ST elevations in V7-V9Posterior descending artery Evolution of MI Morphological Myocardial Changes in an MI Time Gross Feature Light Microscopy Complications 0-24 hours Initially no gross findings; however, over the course of the first 24 hours, dark mottling ensues Early coagulation necrosis Wavy fibers Neutrophil infiltration Arrhythmia Heart failure 1-3 days Mottling with a yellowish infarct center Extensive coagulation necrosisBrisk neutrophil infiltration Fibrinous pericarditis 3-14 days 3-7 dayshyperemic with central yellowing7-10 daysyellow-tan with reddish tan margins10-14 daysreddish gray infarct borders Macrophage infiltration and tissue granulation Myocardial wall rupture - sudden hypotension, tachycardia, and pulseless electrical activity - may lead to cardiac tamponade Papillary muscle rupture -mitral regurgitation Pseudoaneurysm of a ventricular wall - may rupture 2 weeks - several months 2-8 weeksgray-white scar> 2 monthscomplete scar Collagenous scar Dressler syndrome Heart failure True ventricular - aneurysma thrombus may form - evaluate with echocardiograph - ECG with persistent ST elevation in original MI leads with a deep QS wave Presentation Symptoms login to view 14 more bullets Physical exam login to view 3 more bullets Imaging Coronary angiography login to view 2 more bullets Studies 12-lead ECG login to view 32 more bullets Biomarkers login to view 8 more bullets Differential Unstable angina login to view 2 more bullets Hibernating myocardium login to view 3 more bullets Brugada syndrome login to view 3 more bullets Wellens syndrome login to view 2 more bullets De Winter T waves login to view 3 more bullets Cerebral T waves login to view 3 more bullets Arrhythmogenic right ventricular dysplasia login to view 2 more bullets Precordial catch syndrome login to view 2 more bullets Spontaneous coronary artery dissection (SCAD) login to view 2 more bullets Treatment Conservative login to view 2 more bullets Medical login to view 41 more bullets Reperfusion therapy login to view 15 more bullets Complications Heart failure Sudden cardiac death Arrhythmia Myocardial stunning Erectile dysfunction (commonly caused by anxiety)