Which histologic feature characterizes arrhythmogenic right ventricular cardiomyopathy?

Which histologic feature characterizes arrhythmogenic right ventricular cardiomyopathy?

• A. Fibrofatty replacement of the right ventricular myocardium with thinning of the RV wall.
• B. Fibrous scar limited to the left ventricle with thinning of the LV wall.
• C. Fatty infiltration of both ventricles with preserved wall thickness.
• D. Fibrous calcification of the right atrium.

Answer: (A)

Arrhythmogenic right ventricular cardiomyopathy is defined by fibrous and fatty replacement of the right ventricular myocardium, especially in the RV free wall, leading to thinning of the RV wall. This fibrofatty replacement disrupts the myocardial architecture and electrical conduction, predisposing to ventricular arrhythmias that originate from the right ventricle. The pattern is characteristic for the right ventricle rather than the left; other options describe patterns like left ventricular scar, fatty infiltration of both ventricles with preserved wall thickness, or fibrous changes of the right atrium, which do not fit ARVC.

Arrhythmogenic right ventricular cardiomyopathy is defined by fibrous and fatty replacement of the right ventricular myocardium, especially in the RV free wall, leading to thinning of the RV wall. This fibrofatty replacement disrupts the myocardial architecture and electrical conduction, predisposing to ventricular arrhythmias that originate from the right ventricle. The pattern is characteristic for the right ventricle rather than the left; other options describe patterns like left ventricular scar, fatty infiltration of both ventricles with preserved wall thickness, or fibrous changes of the right atrium, which do not fit ARVC.