Which of the following statement is wrong about hyperophic cardiomyopathy ?
**Core Concept**
Hyperophic cardiomyopathy (HCM) is a genetic disorder characterized by the thickening of the heart muscle (myocardium), particularly in the left ventricle. This thickening can lead to impaired cardiac function, arrhythmias, and sudden cardiac death.
**Why the Correct Answer is Right**
The correct answer will be related to the pathophysiology and clinical features of HCM. The myocardial thickening in HCM is due to an abnormal accumulation of myofibrils and an increased number of mitochondria, leading to impaired diastolic relaxation and increased afterload. This can result in symptoms such as chest pain, shortness of breath, and syncope.
**Why Each Wrong Option is Incorrect**
**Option A:** HCM is primarily caused by mutations in genes encoding for sarcomeric proteins, which is correct.
**Option B:** Sudden cardiac death is a common complication of HCM, which is correct.
**Option C:** The myocardial thickening in HCM can lead to outflow tract obstruction, which is correct.
**Option D:** HCM is characterized by a normal or decreased left ventricular cavity size, which is incorrect. In fact, HCM is often associated with a small left ventricular cavity size due to the thickened myocardium.
**Clinical Pearl / High-Yield Fact**
A key feature of HCM is the presence of a "hypertrophied" left ventricle on echocardiography, which can be difficult to distinguish from other forms of cardiomyopathy. It's essential to consider the clinical context, including symptoms and family history, when interpreting echocardiogram results in patients with suspected HCM.
**Correct Answer: D. HCM is characterized by a small left ventricular cavity size.**