Cаrdiоmyоpаthy cаn be separated intо primary (genetic, mixed, or acquired) or secondary categories. Patients present with diverse phenotypes including dilated, hypertrophic, and restrictive patterns. Hypertrophic cardiomyopathy (HCM) is the most common primary cardiomyopathy, and may lead to exertional dyspnea, pre-syncope, atypical chest pain, heart failure, and sudden cardiac death. Which of the following best defines hypertrophic cardiomyopathy?