Patients who receive hydrocortisone therapy after cardiac surgery have a significantly lower risk of developing atrial fibrillation, according to an article in the April 11 issue of the Journal of the American Medical Association.

According to background information in the article, atrial fibrillation is the most common arrhythmia to occur after cardiac surgery. Incidence has been reported to range between 20 percent and 40 percent after coronary artery bypass graft surgery and is even higher after heart valve surgery and combined valve and bypass surgery. The arrhythmia is associated with increased illness, including increased risk of stroke and need for additional treatment, with prolonged hospital stay and increased costs. A postoperative inflammatory response has been thought to be partly responsible for development of the arrhythmia.

Jari Halonen, MD, of Kuopio University Hospital, Kuopio, Finland, and colleagues conducted a randomized multicenter trial to test whether intravenous corticosteroid administration prevents the arrhythmia after cardiac surgery. The study, conducted at three university hospitals in Finland, included 241 patients without prior history of atrial fibrillation who were scheduled to undergo bypass graft surgery, aortic valve replacement, or combined bypass graft surgery and aortic valve replacement.

Patients were randomized to 100-mg hydrocortisone or matching placebo the evening of the operative day, then one dose every 8 hours during the next 3 days. A total of 94 patients developed atrial fibrillation during the first 84 hours after surgery. Patients randomized to hydrocortisone were significantly less likely to develop the arrhythmia than patients randomized to placebo group (36/120 [30 percent] versus 58/121 [48 percent].

Relative risk reduction was 37 percent. The first episode of arrhythmia occurred later in patients randomized to hydrocortisone. The incidence of in-hospital arrhythmia 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.

"We conclude that intravenous administration of hydrocortisone is efficacious and well tolerated in the prevention of atrial fibrillation after cardiac surgery. Larger trials will be needed to confirm our findings and determine short- and long-term safety of corticosteroids to prevent postoperative atrial fibrillation and other arrhythmias," the authors concluded.