Name two common etiologies that most often lead to HFrEF in adults.

• A. Pulmonary embolism and valve stenosis.
• B. Hypertrophic obstructive cardiomyopathy and pericarditis.
• C. Ischemic heart disease and dilated cardiomyopathy.
• D. Primary valvular regurgitation and infectious endocarditis.

Answer: (C)

The main idea is that heart failure with reduced ejection fraction (HFrEF) results from impaired systolic function, and the two most common causes in adults are ischemic heart disease and dilated cardiomyopathy. Ischemic heart disease damages the myocardium through coronary artery disease and prior myocardial infarction, leading to scar tissue and weaker contraction, which lowers the ejection fraction. Dilated cardiomyopathy, even without significant coronary disease, causes enlargement of the ventricles and a decline in contractile strength, producing a reduced ejection fraction as well. Together they account for the majority of HFrEF cases.

Other listed conditions can lead to heart failure, but they’re less commonly the primary drivers of reduced EF in adults.