Which is the most common cause of congestive heart failure after myocardial infarction?

• A. Papillary muscle rupture
• B. Left ventricular aneurysm
• C. Right ventricular infarct
• D. Pericardial effusion

Answer: (B)

After myocardial infarction, persistent heart failure most often stems from the LV not pumping well because scarred, noncontractile tissue and remodeling reduce overall systolic function. A left ventricular aneurysm is a region of infarcted wall that becomes scarred and thinned and then bulges during systole. This abnormal segment drags down the whole ventricle’s function, creating a dilated, poorly contracting chamber that lowers ejection fraction and increases filling pressures, leading to congestive heart failure over time.

This mechanism fits post-MI patients who develop chronic HF. In contrast, papillary muscle rupture is an acute complication causing sudden, severe mitral regurgitation and rapid pulmonary edema; a right ventricular infarct mainly disrupts right-sided function and preload, not the typical left-sided chronic HF; and pericardial effusion causes tamponade physiology rather than a primary chronic HF state.