Which of the following is a cause of dilated cardiomyopathy?

Which of the following is a cause of dilated cardiomyopathy?

• A. Myocarditis (Coxsackie B)
• B. Hypertrophic cardiomyopathy
• C. Pulmonary embolism
• D. Atrial septal defect

Answer: (A)

Viral myocarditis, especially from Coxsackie B, is a classic cause of dilated cardiomyopathy. The infection inflames and injures the heart muscle, impairing its ability to contract. In response to this injury, the ventricle dilates and the systolic function worsens, producing the dilated, poorly contracting heart characteristic of dilated cardiomyopathy. Other options describe different patterns. Hypertrophic cardiomyopathy involves thickened walls rather than dilation. A pulmonary embolism causes acute right‑sided strain and is not a typical driver of chronic dilated cardiomyopathy. An atrial septal defect causes volume overload and shunting that can enlarge chambers, especially on the right, but it’s not a primary myocardial disease that leads to the classic dilated cardiomyopathy pattern.

Viral myocarditis, especially from Coxsackie B, is a classic cause of dilated cardiomyopathy. The infection inflames and injures the heart muscle, impairing its ability to contract. In response to this injury, the ventricle dilates and the systolic function worsens, producing the dilated, poorly contracting heart characteristic of dilated cardiomyopathy.

Other options describe different patterns. Hypertrophic cardiomyopathy involves thickened walls rather than dilation. A pulmonary embolism causes acute right‑sided strain and is not a typical driver of chronic dilated cardiomyopathy. An atrial septal defect causes volume overload and shunting that can enlarge chambers, especially on the right, but it’s not a primary myocardial disease that leads to the classic dilated cardiomyopathy pattern.