Acute Myocardial Infarction 1

Question

Vignette: A 45-year-old man with a history of hypertension presents to the emergency department with severe chest pain radiating to his left arm. His EKG shows ST-segment elevations in leads II, III, and aVF. He is diagnosed with an acute myocardial infarction (MI) and is given aspirin, nitroglycerin, and morphine for pain. Despite treatment, his chest pain does not abate. His cardiac enzymes rise and his condition deteriorates rapidly.

Question: Which of the following is the most likely underlying pathophysiology of this patient's condition?

Choices

A) Coronary artery vasospasm

B) Aortic dissection

C) Coronary artery thrombosis

D) Myocardial rupture

E) Pericarditis

Answer

C) Coronary artery thrombosis

Explanation

The patient's presentation of severe chest pain with radiating to the left arm, ST-segment elevations in leads II, III, and aVF on EKG, and rising cardiac enzymes are classic for acute myocardial infarction (MI). The most common underlying pathophysiology of an MI is coronary artery thrombosis, which is often caused by the rupture of an atherosclerotic plaque. This results in platelet aggregation and clot formation, leading to occlusion of the coronary artery and subsequent myocardial necrosis. Despite administration of antiplatelet (aspirin) and vasodilator (nitroglycerin) agents, some MIs can progress due to the extent of the clot or the presence of other complicating factors.