Which one of the following is the most common cause for ‘Restrictive cardiomyopathy’ :
**Core Concept**
Restrictive cardiomyopathy (RCM) is a type of cardiomyopathy characterized by the stiffening of the heart muscle, leading to impaired diastolic filling and reduced cardiac output. This condition is often caused by an underlying pathological process that affects the myocardial structure or function.
**Why the Correct Answer is Right**
Amyloidosis is the most common cause of restrictive cardiomyopathy, accounting for approximately 50% of cases. The deposition of amyloid fibrils in the myocardium leads to the replacement of normal cardiac tissue, resulting in the characteristic stiffening of the heart muscle. This process disrupts the normal relaxation and filling of the ventricles during diastole, ultimately impairing cardiac function.
**Why Each Wrong Option is Incorrect**
* **Option A:** Hypertrophic cardiomyopathy (HCM) is a different type of cardiomyopathy characterized by the thickening of the heart muscle, not the stiffening seen in RCM.
* **Option B:** Dilated cardiomyopathy (DCM) is a condition where the heart muscle is weakened, leading to an enlargement of the heart chambers, which is distinct from the restrictive filling pattern seen in RCM.
* **Option C:** Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a rare genetic disorder affecting the right ventricle, but it is not a common cause of restrictive cardiomyopathy.
**Clinical Pearl / High-Yield Fact**
Amyloidosis can be caused by various factors, including aging, genetic predisposition, or chronic inflammation. The deposition of amyloid fibrils can also be associated with other systemic diseases, such as multiple myeloma or chronic infections.
**Correct Answer:** C.