Amiodarone plus Ranolazine for Conversion of Post-Cardiac Surgery Atrial Fibrillation: Enhanced Effectiveness in Reduced Versus Preserved Ejection Fraction Patients

Abstract

Purpose: Ranolazine (RAN) added to amiodarone (AMIO) has been shown to accelerate termination of postoperative atrial fibrillation (POAF) following coronary artery bypass surgery in patients without heart failure (HF). This study aimed to investigate if treatment efficacy with AMIO or AMIO + RAN differs between patients with concomitant HF with reduced or preserved ejection fraction (HFrEF or HFpEF).

Methods: Patients with POAF and HFrEF (n = 511, 446 males; 65 ± 9 years) and with HFpEF (n = 301, 257 males; 66 ± 10 years) were enrolled. Onset of AF occurred 2.15 ± 1.0 days after cardiac surgery, and patients within each group were randomly assigned to receive either AMIO monotherapy (300 mg in 30 min + 1125 mg in 36 h iv) or AMIO+RAN combination (500 mg po + 375 mg, after 6 h and 375 mg twice daily thereafter). Primary endpoint was the time to conversion of POAF within 36 h after initiation of treatment.

Results: AMIO restored sinus rhythm earlier in HFrEF vs. in HFpEF patients (24.3 ± 4.6 vs. 26.8 ± 2.8 h, p < 0.0001). AMIO + RAN converted POAF faster than AMIO alone in both HFrEF and HFpEF groups, with conversion times 10.4 ± 4.5 h in HFrEF and 12.2 ± 1.1 h in HFpEF patients (p < 0.0001). Left atrial diameter was significantly greater in HFrEF vs. HFpEF patients (48.2 ± 2.6 vs. 35.2 ± 2.9 mm, p < 0.0001). No serious adverse drug effects were observed during AF or after restoration to sinus rhythm in any of the patients enrolled.

Conclusion: AMIO alone or in combination with RAN converted POAF faster in patients with reduced EF than in those with preserved EF. Thus, AMIO + RAN seems to be a valuable alternative treatment for terminating POAF in HFrEF patients.

Keywords: Amiodarone; Cardiac surgery; Heart failure; Postoperative atrial fibrillation; Ranolazine.