What is damaged in dilated cardiomyopathy and what does it result in?

• A. Myocytes are injured and necrosis occurs with myocardial fibrosis
• B. Endocardial plaque formation leading to stenosis
• C. Valve leaflets calcify causing regurgitation
• D. Pericardial effusion leading to tamponade

Answer: (A)

In dilated cardiomyopathy, the heart muscle cells (myocytes) are damaged and may undergo necrosis with replacement by fibrous tissue. This injury weakens the ventricular walls, leading to dilation of the ventricles and impaired systolic function. The resulting decline in ejection fraction produces heart failure symptoms, and the fibrotic changes can contribute to arrhythmias and functional mitral regurgitation from annular dilation. The other options describe processes from unrelated conditions—atherosclerotic plaques causing stenosis, valvular calcification causing regurgitation, and pericardial effusion with tamponade.