1. The efficacy of verapamil alone, or in combination with digoxin, was compared with digoxin alone in eight patients with chronic atrial fibrillation in this double-blind placebo-controlled study.
2. After 2 weeks on each treatment regimen, heart rate at rest and during progressive load treadmill exercise, left ventricular function at rest and nocturnal heart rate were measured.
3. Oral verapamil alone at a dose of 80 mg three times daily, or 40 mg of verapamil three times daily in combination with 0.25 mg of digoxin daily, was superior to digoxin alone in doses associated with high serum digoxin concentrations (mean ± sem 1.6 ± 0.3 μg/l). This superiority manifested as greater control of heart rate during work rates equivalent to regular daily activities, and was not associated with deterioration in left ventricular function or worsening nocturnal bradycardia.
4. We conclude that the treatment of choice in patients with chronic atrial fibrillation is either 80 mg of verapamil three times daily or 40 mg of verapamil three times daily in combination with digoxin.