ACC 2016: Two strategies are equally effective for post-operative atrial fibrillation

by Bruce Sylvester: Rhythm control and rate control are similarly effective in treating post-operative atrial fibrillation, researchers reported on April 4, 2016 at the American College of Cardiology 2016 annual meeting.

“For the primary endpoint of total number of days in the hospital from the date that therapy was started until 60 days after beginning treatment, we found that for the stable post-surgical patient, rate control and rhythm control are both acceptable strategies,” said lead investigator Marc Gillinov, M.D., a cardiac surgeon at the Cleveland Clinic in Cleveland, Ohio. “This is important because it means that the choice of strategy can be determined by what is clinically preferable for the individual patient,” he added.

As background, the authors noted that postoperative atrial fibrillation is the most common

complication after cardiac surgery. It increases morbidity, mortality, length of stay and resource utilization. However, guidelines for choosing optimal management of postoperative atrial fibrillation (AFib) in stable patients lack a rigorous evidence base, and there are wide variations in clinical practice.

The investigators in the US and Canada enrolled 2,109 subjects who were about to undergo either bypass or valve replacement/valve repair surgery. Subjects experiencing an episode of AFib lasting more than 60 minutes, or more than one AFib episode during the first seven days after surgery, were eligible to randomization to one of the two study treatment groups.

Five-hundred and twenty-three subjects who manifested postoperative Afib were randomized to heart rate control treatment with beta blockers or heart rhythm control treatment with amiodarone, with or without electrical cardioversion to restore normal rhythm.

All subjects who had recurrent AFib or AFib lasting over 48 hours were also eligible to receive warfarin.

Average subject age was 68 years, and 75 percent were male.

The follow-up period was 60 days after surgery.

The researchers reported that, at 60 days, lengths of stay in the hospital, the primary endpoint, were 5.1 days for the rate control group and 5.0 days for the rhythm control group.

The proportion of patients who were AFib-free at 60 days, the secondary endpoint, was 93.8 percent for the rate control group and 97.9 percent for the rhythm control group.

Even though the differences in findings were not statistically significant, there were some clinical differences, Gillinov noted. While subjects in the rhythm control group were slightly more likely to be  Afib-free at 60 days, they had adverse effects associated with amiodarone use. Subjects the rate control group had fewer treatment side effects but were slightly more likely to have AFib at the end of the follow-up.

The study was not powered to detect outcome differences between patients who received warfarin and those who did not. This question may be the focus of a follow-up study, Gillinov said.