Atrial fibrillation (AF) is the most common arrhythmia to occur after cardiac surgery. The incidence of AF has been reported to range between 20 percent and 40 percent after coronary artery bypass graft (CABG) surgery and is even higher after heart valve surgery and combined valve and bypass surgery.

AF is associated with increased illness, including increased risk of stroke and need for additional treatment, with prolonged hospital stay and increased costs. A high inflammatory response after surgery has been thought to be partly responsible for AF.

Jari Halonen, M.D., of Kuopio University Hospital, Kuopio, Finland, and colleagues conducted a randomized multicenter trial to test whether intravenous corticosteroid administration prevents AF after cardiac surgery. The study included 241 patients without prior AF who were scheduled to undergo CABG surgery, aortic valve replacement, or combined CABG surgery and aortic valve replacement. Patients were randomized to receive either 100-mg hydrocortisone or matching placebo the evening of the operative day, then 1 dose every 8 hours during the next 3 days.

There were 94 patients who had AF during the first 84 hours after cardiac surgery. Patients randomized to the hydrocortisone group were significantly less likely to have AF than patients randomized to the placebo group (36/120 [30 percent] vs. 58/121 [48 percent]. The relative risk reduction was 37 percent.

The first AF episode occurred later in patients randomized to the hydrocortisone group. The incidence of in-hospital AF was also significantly lower in the hydrocortisone group than in the placebo group. Compared with those receiving placebo, patients receiving hydrocortisone did not have higher rates of infections or major complications.; Source: American Medical Association