Comparison of effectiveness of ranolazine plus amiodarone versus amiodarone alone for conversion of recent-onset atrial fibrillation

Abstract

Ranolazine, an antianginal agent with antiarrhythmic properties, prevents atrial fibrillation (AF) in patients with acute coronary syndrome. In experimental models, the combination of ranolazine and amiodarone has marked synergistic effects that potently suppress AF. Currently, the clinical effect of the ranolazine-amiodarone combination for the conversion of AF is unknown. This prospective randomized pilot study compared the safety and efficacy of ranolazine plus amiodarone versus amiodarone alone for the conversion of recent-onset AF. We enrolled 51 consecutive patients with AF (<48-hour duration) eligible for pharmacologic cardioversion. Patients (33 men, 63 ± 8 years of age) were randomized to intravenous amiodarone for 24 hours (group A, n = 26) or to intravenous amiodarone plus oral ranolazine 1,500 mg at time of randomization (group A + R, n = 25). The 2 groups were well balanced with respect to clinical characteristics and left atrial diameter. Conversion within 24 hours (primary end point) was achieved in 22 patients (88%) in group A + R versus 17 patients (65%) in group A (p = 0.056). Time to conversion was shorter in group A + R than in group A (9.8 ± 4.1 vs 14.6 ± 5.3 hours, p = 0.002). According to Cox regression analysis, left atrial diameter and A + R treatment were the only independent predictors of time to conversion (hazard ratio 5.35, 95% confidence interval 2.37 to 12.11, p <0.001; hazard ratio 0.81, 95% confidence interval 0.74 to 0.88, p <0.001, respectively). There were no proarrhythmic events in either group. In conclusion, addition of ranolazine to standard amiodarone therapy is equally safe and appears to be more effective compared to amiodarone alone for conversion of recent-onset AF.