A 57-year-old unconscious man is brought to the emergency department by his wife. Thirty minutes prior, the patient developed severe chest pain and asked to be taken to the hospital. On the way, he became unresponsive. According to his wife, the patient had been having intermittent, short-lived episodes of chest pain over the past several days. The patient's medical history is significant for hypertension, type 2 diabetes mellitus, and hypercholesterolemia. He is not adherent with medications or follow-up. In the emergency department, the patient has no spontaneous respirations or circulation and is pronounced dead. An autopsy examination is performed, and a cross-section of the mid-right coronary artery is shown in the exhibit.
Which of the following is the most likely immediate cause of death in this patient?

Question

A 57-year-old unconscious man is brought to the emergency department by his wife.  Thirty minutes prior, the patient developed severe chest pain and asked to be taken to the hospital.  On the way, he became unresponsive.  According to his wife, the patient had been having intermittent, short-lived episodes of chest pain over the past several days.  The patient's medical history is significant for hypertension, type 2 diabetes mellitus, and hypercholesterolemia.  He is not adherent with medications or follow-up.  In the emergency department, the patient has no spontaneous respirations or circulation and is pronounced dead.  An autopsy examination is performed, and a cross-section of the mid-right coronary artery is shown in the exhibit.  
Which of the following is the most likely immediate cause of death in this patient?

Quizplus · Accepted Answer

11ec160b_38db_9a46_9249_9fb7d1b2d649_MD0001_00 This patient's clinical features are suggestive of coronary artery disease (chest pain and multiple risk factors) causing an acute myocardial infarction (MI). The diagnosis is confirmed by autopsy showing a large atheromatous plaque with superimposed thrombosis causing complete obstruction of the right coronary artery. Acute MI is a common cause of sudden cardiac death (SCD) (the abrupt cessation of organized cardiac activity leading to hemodynamic collapse and inadequate tissue perfusion). SCD due to acute MI usually results from a malignant ventricular arrhythmia (ie, ventricular fibrillation or ventricular tachycardia degenerating to ventricular fibrillation) that is triggered by electrical instability in the ischemic myocardium. (Choice A) Atrial fibrillation can sometimes occur during acute MI; however, organ perfusion is usually maintained and it is not a common cause of SCD. (Choices B and F) Ventricular septal rupture (most common with left anterior descending artery occlusion) and cardiac free wall rupture are mechanical complications of acute MI that typically occur several days following the event. Septal rupture can sometimes occur acutely, but it is likely to cause symptomatic cardiogenic shock (eg, hypotension, respiratory distress/failure) rather than SCD. (Choice C) Embolic stroke can result from embolization of a left ventricular (LV) mural thrombus that forms in an area of infarcted and akinetic myocardium. However, LV thrombus typically takes several days to form, and embolic stroke does not typically lead to SCD. (Choice D) Acute MI commonly causes regional contractile dysfunction in the area of myocardium supplied by the affected artery. Infarction involving >50% of the myocardium can cause ventricular failure and cardiogenic shock, typically presenting with hypotension and respiratory distress rather than SCD. Educational objective: Ventricular fibrillation is the most common mechanism of sudden cardiac death due to acute myocardial infarction. It results from arrhythmogenic foci triggered by electrical instability in the ischemic myocardium.

A 57-Year-Old Unconscious Man Is Brought to the Emergency Department