Atrial fibrillation and HCM:
AF occurs in 20% of patients with HCM (4-fold increase than in the general population).
AF can cause sudden, and sometimes severe, deterioration in symptoms and exercise capacity and is associated with a high risk of thromboembolism.
Restoration of sinus rhythm usually results in a substantial improvement in symptoms, and amiodarone is effective in preventing recurrences.
Control of the ventricular rate with beta blockers, calcium antagonists, or both is almost as effective. Because of the potentially adverse effects of digoxin in patients with hypertrophic cardiomyopathy and normal systolic function, this drug is not routinely recommended for rate control.