In a patient with hypertrophic cardiomyopathy, which intervention is most effective in avoiding common complications such as arrhythmias and sudden cardiac death?

Hypertrophic cardiomyopathy involves asymmetric myocardial hypertrophy, diastolic dysfunction, and possible left ventricular outflow tract obstruction, with increased risk of ventricular arrhythmias and sudden cardiac death due to disorganized myocardial fiber architecture and electrical instability. Rationale: A. Diuretics reduce preload, which can worsen left ventricular outflow tract obstruction in hypertrophic cardiomyopathy by decreasing ventricular filling. This may exacerbate symptoms such as syncope and hypotension rather than prevent arrhythmias. B. Digoxin increases myocardial contractility, which can intensify outflow obstruction and increase the risk of arrhythmias in hypertrophic cardiomyopathy. It is generally avoided in obstructive forms of the disease. C. High-intensity exercise increases myocardial oxygen demand and can trigger malignant arrhythmias, syncope, or sudden cardiac death in patients with hypertrophic cardiomyopathy. Strenuous activity is contraindicated. D. An implantable cardioverter-defibrillator (ICD) is the most effective intervention for preventing sudden cardiac death in high-risk hypertrophic cardiomyopathy patients. It continuously monitors cardiac rhythm and delivers life-saving shocks for ventricular tachycardia or ventricular fibrillation.