A 25 years old basketball player suddenly collapsed while undergoing an athletic event and died . At autopsy the septum was hyperophied . The most probable diagnosis is

Ref Harrison 19 th ed pg 1568 The substantial variability of hyperophic cardiomyopathy pathology is reflected in the diversity of clinical presentations. Patients may be diagnosed after undergoing evaluations triggered by the abnormal physical findings (murmur) or symptoms of exeional dyspnea, angina, or syncope. Alternatively, diagnosis may follow evaluations prompted by the detection of disease in family members.