Which of the following is NOT a complication of an acute myocardial infarction?

• A. Dysrhythmias
• B. Ventricular septal defect
• C. Pneumonia
• D. Dressler's syndrome

Answer: (C)

When a myocardial infarction happens, the heart tissue injury sets off several direct complications tied to the heart’s electrical, mechanical, and inflammatory responses. Dysrhythmias arise because ischemia disrupts the heart’s conduction system, so abnormal rhythms can appear suddenly and threaten hemodynamics. A ventricular septal defect is a mechanical complication that can occur when necrosis weakens the interventricular septum, allowing blood to shunt from left to right and causing acute heart failure signs. Dressler’s syndrome is an inflammatory, autoimmune pericarditis that can develop weeks after the MI, presenting with chest pain and fever.

Pneumonia, on the other hand, is not a direct consequence of the myocardial infarction itself. It may occur during a hospital stay due to factors like aspiration or immobility, but it does not arise from the infarct’s pathophysiology. Therefore, pneumonia is not a complication caused by the MI, making it the best choice for not fitting with the others.