Antiarrhythmic drugs ( AADs ) and anticoagulation are mainstays of atrial fibrillation ( AF ) treatment. A study has assessed the use and outcomes of antiarrhythmic therapy in anticoagulated patients with atrial fibrillation.
Patients in the ROCKET ( Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation ) trial ( N = 14,264 ) were stratified by antiarrhythmic drugs use at baseline: Amiodarone [ Cordarone ], other antiarrhythmic drug, or no antiarrhythmic drug.
Multivariable adjustment was performed to compare stroke, bleeding, and death across antiarrhythmic drug groups as well as across treatment assignment ( Rivaroxaban [ Xarelto ] or Warfarin [ Coumadin ] ).
Of 14,264 patients randomized, 1681 ( 11.8% ) were treated with an antiarrhythmic drug ( 1144 [ 8% ] with Amiodarone and 537 [ 3.8% ] with other antiarrhythmic drugs ).
Amiodarone-treated patients were less often female ( 38% vs 48% ), had more persistent atrial fibrillation ( 64% vs 40% ), and more concomitant heart failure ( 71% vs 41% ) than were patients receiving other antiarrhythmic drugs.
Patients receiving no antiarrhythmic drug more closely resembled Amiodarone-treated patients.
Time in therapeutic range was significantly lower in warfarin-treated patients receiving Amiodarone than in those receiving no antiarrhythmic drug ( 50% vs 58%; P less than 0.0001 ).
Compared with no antiarrhythmic drug, neither Amiodarone ( adjusted hazard ratio [ HR ] 0.98; 95% confidence interval [ CI ] 0.74–1.31; P = 0.9 ) nor other antiarrhythmic drugs ( adjusted HR 0.66; 95% CI 0.37–1.17; P = 0.15 ) were associated with increased mortality.
Similar results were observed for embolic and bleeding outcomes.
Treatment effects of Rivaroxaban vs Warfarin in patients receiving no antiarrhythmic drug were consistent with results from the overall trial ( primary end point: adjusted HR 0.82; 95% CI 0.68–0.98; P interaction = 0.06; safety end point: adjusted HR 1.12; 95% CI 0.90–1.24; P interaction = 0.33 ).
In conclusion, treatment with antiarrhythmic drugs was not associated with increased morbidity or mortality in anticoagulated patients with atrial fibrillation.
The effect of Amiodarone on outcomes in patients receiving Rivaroxaban requires further investigation. ( Xagena )
Steinberg BA et al, Heart Rhythm 2014; 11: 925–932