Snapshot A 55-year-old man presents to the emergency department due to substernal chest pain. His symptoms began a few hours ago. He describes the pain as "crushing" and it radiates down the left arm. Medical history is significant for type 2 diabetes and hypertension. On physical exam the patient is diaphoretic. An electrocardiogram demonstrates ST-segment elevations and cardiac troponins are significantly elevated. Introduction Clinical definition death of myocardial tissue secondary to prolonged and severe ischemia also known as a "heart attack" Types ST-segment elevation myocardial infarction (STEMI) an acute coronary syndrome (ACS) with ST-segment elevations found on electrocardiogram (ECG) biomarkers of myocardial necrosis are present Non-STEMI (NSTEMI) an ACS without ST-segment elevations found on ECG biomarkers of myocardial necrosis are present unstable angina an ACS without ST-segment elevations found on ECG and no elevation biomarkers of myocardial necrosis Epidemiology incidence increases with age risk factors hypertension cigarette smoking hyperlipidemia hypercholesterolemia male postmenopause genetic and behavioral predispositions to arteriosclerosis e.g., high-fat diet Etiology occlusion of a coronary artery can be caused by atheromatous plaque rupture with subsequent thrombi expansion vasospasm emboli, which can be secondary to atrial fibrillation, sending an embolus from the left atrium to the coronary arteries vegetations from infective endocarditis material from an intracardiac prosthetic paradoxical emboli Pathophysiology occlusion of a coronary artery disrupts the blood supply to a region in the myocardium ischemia ensues, the myocytes become rapidly dysfunctional when ischemia persists, this can result in myocyte death after 30 minutes of severe ischemia, the damage becomes irreversible infarction patterns subendocardial myocyte necrosis involving the inner cardiac wall this is normally the least perfused portion of the myocardium may be referred to as an NSTEMI transmural myocyte necrosis involving the full thickness of the cardiac wall may be referred to as a STEMI ECG Changes and STEMI ECG Changes and STEMI Infarction Location Involved ECG Leads Involved Coronary Artery Inferior wall II, III, and aVF RCA Antero-apical V3 and V4 LAD (distal) Antero-septal V1 and V2 LAD Antero-lateral V5 and V6 LAD or LCX Lateral I and aVL LCX Posterior ST depression and tall R waves in V1-3 V7-V9 Posterior descending artery Evolution of MI Morphological Myocardial Changes in an MI Time Gross Features 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 Elongated myocytes Neutrophil infiltration Arrhythmia Heart failure 1-3 days Mottling with a yellowish infarct center Extensive coagulation necrosis Brisk neutrophil infiltration Fibrinous pericarditis 3-14 days 3-7 days hyperemic with central yellowing 7-10 days yellow-tan with reddish tan margins 10-14 days reddish gray infarct borders Macrophage infiltration and tissue granulation Myocardial wall rupture may lead to cardiac tamponade Papillary muscle rupture mitral regurgitation posterolateral muscle rupture is more likely than anteromedial muscle rupture Pseudoaneurysm of a ventricular wall may rupture 2 weeks - several months 2-8 weeks gray-white scar > 2 months complete scar Collagenous scar Dressler syndrome Heart failure True ventricular aneurysm a thrombus may form Presentation Symptoms chest pain features squeezing crushing substernal radiation jaw neck left shoulder or down the arm nausea and vomiting dyspnea asymptomatic typically seen in patients with diabetic neuropathy nerve fibers are damaged and impair their ability to sense pain Physical exam diaphoresis variable findings e.g., S3 or S4, signs of heart failure, bradycardia (in cases of an inferior wall MI) Imaging Coronary angiography indication diagnostic study to assess coronary anatomy and to determine where the occlusion is Studies 12-lead ECG perform as soon as possible findings STEMI hyperacute or peaked T-waves earliest finding ST elevation Q waves a late finding (~2 weeks post-MI) new left bundle branch block (LBBB) considered to be an equivalent to a STEMI NSTEMI ST depression T wave inversion Late pathologic Q waves Q wave in leads V2–V3 lasting longer than 0.02 seconds Q wave anywhere lasting longer than 0.03 seconds with an amplitude greater than 0.1 mV Biomarkers Troponin preferred marker as it has a high sensitivity and specificity for myocardial necrosis troponin I increases after 4 hours and peaks around 24 hours remains elevated for 7-10 days CK-MB a sensitive but not specific biomarker since skeletal muscle can also release it useful for assessing reinfarction Differential Unstable angina differentiating factor no elevation in cardiac biomarkers Costochondritis differentiating factor chest pain that is reproducible with palpation Treatment Conservative lifestyle modification e.g., smoking cessation Medical initial medical treatments include aspirin oxygen nitroglycerin hypotension in an inferior wall infarction secondary to reduced preload morphine only give if there is unacceptable pain appears to be associated with a mortality increase P2Y12 (ADP) receptors blockers indication given in addition to aspirin heparin indication given in addition to antiplatelet therapy β-blockers indication given to all patients if there are no contraindications statin indication given to all patients angiotensin-converting enzyme (ACE) inhibitor indication given to patients with a myocardial infarction recommended when there is anterior infarction heart failure left ventricular ejection fraction < 40% reduces mortality contraindication shock bilateral renal artery stenosis allergy Reperfusion therapy percutaneous coronary intervention (PCI) indications if STEMI symptoms developed in < 12 hours and the procedure can be performed within 90-120 minutes if fibrinolytic therapy is contraindicated coronary artery bypass graft (CABG) indication when coronary anatomy does not allow for PCI 3 vessel occlusion or 2 vessel occlusion in a patient with diabetes significant stenosis of the left main coronary artery fibrinolytic therapy indication for patients who cannot receive PCI within 120 minutes Complications Heart failure Sudden cardiac death Arrhythmia Myocardial stunning
QUESTIONS 1 of 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (M1.CV.15.75) A 68-year-old male with a history of type 2 diabetes, hypertension, and COPD presents to the emergency department with severe substernal chest pain. On exam, he is diaphoretic and in obvious distress. An EKG is obtained which is demonstrated in Figure F. He immediately receives treatment for his condition and is subsequently admitted to the cardiac intensive care unit (CICU). In the CICU, he does well until day 5 of hospitalization when he begins to complain of severe shortness of breath and chest pain. Vitals are noted to be T: 36 deg C, HR: 130 bpm, BP: 65/40 mmHg, RR: 12, SaO2: 98%. He is clearly in distress and has elevated JVP. Which of the following histologic images would you expect to see if a biopsy of the myocardium was performed on this patient? QID: 106815 FIGURES: A B C D E F Type & Select Correct Answer 1 Figure A 8% (19/248) 2 Figure B 17% (42/248) 3 Figure C 12% (29/248) 4 Figure D 29% (72/248) 5 Figure E 32% (80/248) M 1 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review Tested Concept Review Full Topic (M1.CV.13.138) A 62-year-old male collapses while mowing the lawn, and it is determined that he experienced sudden cardiac death. The patient's medical history is significant for a preceding myocardial infarction that was managed conservatively. Posthumous histologic evaluation of the patient's heart reveals extensive granulation tissue replacing dead myocardium as well as early evidence of neovascularization, which is shown in Figure A. How long prior to death did this patient most likely experience his myocardial infarction? QID: 100654 FIGURES: A Type & Select Correct Answer 1 16 hours 2% (2/98) 2 3 days 12% (12/98) 3 8 days 27% (26/98) 4 2 weeks 44% (43/98) 5 2 months 11% (11/98) M 1 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (M1.CV.13.35) A 64-year-old male with a past medical history of obesity, diabetes, hypertension, and hyperlipidemia presents with an acute onset of nausea, vomiting, diaphoresis, and crushing substernal chest pain. Vital signs are temperature 37° C, HR 110, BP 149/87, and RR of 22 with an oxygen saturation of 99% on room air. Physical exam reveals a fourth heart sound (S4), and labs are remarkable for an elevated troponin. EKG is shown below. The pathogenesis of the condition resulting in this patient’s presentation involves: QID: 100551 FIGURES: A Type & Select Correct Answer 1 Genetic inheritance of a mutation in ß-myosin or troponin expressed in cardiac myocytes 6% (8/135) 2 A fully obstructive thrombus at the site of a ruptured, ulcerated atherosclerotic plaque 80% (108/135) 3 A partially occlusive thrombus at the site of a ruptured, ulcerated atherosclerotic plaque 11% (15/135) 4 Destruction of the vasa vasorum caused by vasculitic phenomena 1% (2/135) 5 A stable atheromatous lesion without overlying thrombus 0% (0/135) M 1 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review Tested Concept Review Full Topic (M1.CV.13.25) A 53-year-old man with a past medical history significant for hyperlipidemia, hypertension, and hyperhomocysteinemia presents to the emergency department complaining of 10/10 crushing, left-sided chest pain radiating down his left arm and up his neck into the left side of his jaw. His ECG shows ST-segment elevation in leads V2-V4. He is taken to the cardiac catheterization laboratory for successful balloon angioplasty and stenting of a complete blockage in his left anterior descending coronary artery. Echocardiogram the following day shows decreased left ventricular function and regional wall motion abnormalities. A follow-up echocardiogram 14 days later shows a normal ejection fraction and no regional wall motion abnormalities. This post-infarct course illustrates which of the following concepts? QID: 100541 Type & Select Correct Answer 1 Reperfusion injury 13% (33/247) 2 Ventricular remodeling 19% (46/247) 3 Myocardial hibernation 15% (38/247) 4 Myocardial stunning 43% (107/247) 5 Coronary collateral circulation 9% (21/247) M 1 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic (M1.CV.13.102) A 60-year-old woman with history of type I diabetes currently on hormone replacement therapy is seen in your ED complaining of "bad indigestion", dizziness and nausea for the past several hours. Vitals are T98.9, HR 102, BP 130/100, RR 25 and she is mildly diaphoretic. An EKG is shown in Figure A. At what time point does the injury to her affected cells become irreversible? QID: 100618 FIGURES: A Type & Select Correct Answer 1 5 seconds 4% (13/318) 2 60 seconds 11% (34/318) 3 10 minutes 21% (66/318) 4 30 minutes 39% (125/318) 5 1 hour 18% (57/318) M 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic (M1.CV.13.34) An autopsy is being performed on an elderly man who died from a myocardial infarction. Biopsy of the heart is likely to reveal necrosis most similar to necrosis seen in which of the following scenarios? QID: 100550 Type & Select Correct Answer 1 The central nervous system following a stroke 6% (11/188) 2 The lung following a tuberculosis infection 6% (12/188) 3 Acute pancreatitis resulting from release of enzymatically active enzymes into the pancreas 3% (6/188) 4 A region of kidney where blood flow is obstructed 80% (151/188) 5 An abscess 2% (4/188) M 1 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK
All Videos (4) Login to View Community Videos Login to View Community Videos Complications after a Myocardial Infarction Chris Robinson Cardiovascular - Myocardial Infarction D 2/24/2015 96 views 5.0 (3) Login to View Community Videos Login to View Community Videos Resolution of a Myocardial Infarction Chris Robinson Cardiovascular - Myocardial Infarction D 2/24/2015 48 views 5.0 (1) Login to View Community Videos Login to View Community Videos Myocardial Infarction Medications Chris Robinson Cardiovascular - Myocardial Infarction E 2/24/2015 57 views 0.0 (0) Cardiovascular | Myocardial Infarction Cardiovascular - Myocardial Infarction Listen Now 23:44 min 5/16/2021 166 plays 5.0 (1) See More See Less