Patients in the amiodarone plus ranolazine group compared with the amiodarone-only group showed significantly higher conversion rates at 24 h ( 87 vs. 70 % , respectively ; P = 0.024 ) and at 12 h ( 52 vs. 32 % ; P = 0.021 ) , and shorter time to conversion ( 10.2 3.3 vs. 13.3 4.1 h ; P = 0.001 ) .