A 25-year-old man suffers a sudden cardiac arrest. He is resuscitated. On examination his vital signs are normal. Echocardiography shows that the left ventricle is normal but there is marked thinning with dilation of the right ventricle. MR imaging of his chest shows extensive fibrofatty replacement of the myocardium, but no inflammation. Which of the following is the most likely cause for his findings?

**Core Concept**
The case describes a young patient with right ventricular (RV) dilation and thinning, along with evidence of myocardial scarring, in the absence of acute inflammation. This presentation is characteristic of a condition where the myocardium undergoes a process of fibrofatty replacement, leading to chamber enlargement and dysfunction.

**Why the Correct Answer is Right**
The patient's findings are consistent with arrhythmogenic right ventricular cardiomyopathy (ARVC), a condition characterized by fibrofatty replacement of the RV myocardium. This process leads to thinning and dilation of the RV, along with scarring and potential arrhythmias. The absence of inflammation and normal left ventricular function further support this diagnosis.

**Why Each Wrong Option is Incorrect**
* **Option A:** Coronary artery disease typically presents with left ventricular involvement and would show evidence of acute inflammation on imaging.
* **Option B:** Hypertrophic cardiomyopathy is characterized by left ventricular hypertrophy and outflow tract obstruction, which is not present in this patient.
* **Option C:** Dilated cardiomyopathy is a condition of global left ventricular dysfunction, which is not consistent with this patient's normal left ventricular function.

**Clinical Pearl / High-Yield Fact**
ARVC is a leading cause of sudden cardiac death in young athletes, highlighting the importance of screening for this condition in susceptible populations.

**Correct Answer:** D.

✓ Correct Answer: A. Cardiomyopathy