What is the primary therapeutic approach for a patient with hypertrophic cardiomyopathy?

Hypertrophic cardiomyopathy (HCM) is a genetic myocardial disorder characterized by asymmetric left ventricular hypertrophy, impaired diastolic relaxation, and possible dynamic left ventricular outflow tract obstruction. It leads to reduced ventricular compliance, exertional dyspnea, chest pain, syncope, and risk of sudden cardiac death due to arrhythmias. Rationale: A. Diuretics may reduce preload and worsen left ventricular filling in HCM. Excessive volume reduction can aggravate outflow obstruction and decrease cardiac output. This does not improve diastolic dysfunction and may worsen symptoms. B. Surgical valve replacement is not a standard treatment for hypertrophic cardiomyopathy. HCM is a myocardial disease, not primarily a valvular disorder. This does not address septal hypertrophy or diastolic impairment. C. High-intensity physical activity increases myocardial oxygen demand and can trigger arrhythmias or sudden cardiac death in HCM patients. Exercise is usually restricted to low-to-moderate intensity. This worsens risk of hemodynamic instability. D. Beta-blockers are first-line therapy because they reduce heart rate, prolong diastole, and improve ventricular filling. They also decrease outflow tract obstruction and myocardial oxygen demand. This directly improves diastolic function and symptom control.