Authors: Gillinov AM et al., N Engl J Med 2016 Apr 4;
In a randomized comparison with rate control, rhythm control conferred no net clinical benefit.
Atrial fibrillation (AF) occurs after cardiac surgery in up to 50% of patients. In a study funded by the NIH and the Canadian Institutes of Health Research, investigators compared aggressive rhythm-control treatment with simpler rate-control treatment of postoperative AF.
Of 2109 patients without prior AF undergoing cardiac surgery at 23 U.S. and Canadian sites, 695 developed AF (33%) an average of 2.4 days after surgery, and 523 were randomized to standard therapy for rate control or to amiodarone with cardioversion if needed for rhythm control. Anticoagulation was recommended for all patients with persistent or recurrent AF within 48 hours after randomization.
In the rate-control group, 27% of patients received amiodarone and 9.2% underwent cardioversion (vs. 13.8% of rhythm-control patients). In the rhythm-control group, 24% of patients did not complete the full course of amiodarone.
Compared with rate control, rhythm control was not associated with a significant difference in total number of in-hospital days within 60 days after randomization (median, 5.0 vs. 5.1), death (2 vs. 3), or serious adverse events (26.4 vs. 24.8 per 100 patient-months). Warfarin administration at discharge — a frequently cited reason for rhythm control — also did not differ significantly between the two groups (43.3% vs. 42.7%). The proportion of patients in sinus rhythm between 30 and 60 days after randomization was 97.9% in the rhythm-control group versus 93.8% in the rate-control group (P=0.02). However, overall freedom from AF after discharge did not differ significantly between the two groups (86.9% vs. 84.2%).
These findings seem to suggest that pursuing sinus rhythm in patients with postoperative AF is unnecessary. Yet the extremely high crossover rate renders this conclusion problematic. As this study demonstrates, the treatment course in these patients is complex and fluid, depending upon symptoms, heart-rate control, and variable efficacy and adverse effects of the drugs used. Although it may be somewhat less aggressive, my approach to treatment of postoperative AF will not change dramatically based on these results.