Dilated cardiomyopathy is best described as what combination of changes?

• A. Dilated left ventricle with systolic impairment
• B. Hypertrophy with preserved systolic function
• C. Diastolic dysfunction without dilation
• D. Right ventricular dilation only

Answer: (A)

Dilated cardiomyopathy is defined by dilation of the left ventricle with impaired systolic function, leading to reduced ejection fraction. The heart muscle becomes weaker and the ventricle enlarges, so pumping is less effective. This pattern is what sets DCM apart from other cardiomyopathies.

On imaging, you’d expect an enlarged LV that contracts poorly (low ejection fraction), sometimes with involvement of the right ventricle, but without the thickened walls seen in hypertrophic cardiomyopathy. That’s why the description “dilated left ventricle with systolic impairment” best fits.

In contrast, hypertrophy with preserved systolic function describes a different disease process where walls are thickened and pumping is still relatively preserved; diastolic dysfunction without dilation points to a stiff, non-dilated ventricle; right ventricular dilation alone does not capture the typical left-dominant dilation and reduced systolic function of DCM.