Brief Amiodarone Rx Cuts Atrial Fib After Heart Surgery

NEW ORLEANS — Two weeks of treatment with amiodarone starting immediately after cardiac surgery was safe and cut the postsurgical incidence of atrial fibrillation by an absolute rate of 10% in a study with more than 600 patients.

Atrial fibrillation has historically been the most common arrhythmia complication following cardiac surgery, Dr. James R. Cook and his associates said in a poster at the annual scientific sessions of the American Heart Association.

Results from previous studies had shown that perioperatively administered amiodarone was effective for reducing the incidence of atrial fibrillation, but in some cases the treatment was difficult to maintain and the adverse effects presented a problem. This led to the idea of limiting amiodarone treatment to a brief period immediately following surgery, the investigators said.

The study included 311 patients who underwent coronary artery bypass surgery, valve surgery, or combined bypass and valve surgery (either aortic or mitral valve) at Baystate Medical Center in Springfield, Mass., during July-December 2007. All of these patients received a 150-mg bolus of amiodarone immediately after their surgery was complete, followed by a 400-mg oral dose b.i.d. for the first 7 days after surgery. Patients were then switched to 200 mg orally once daily for the next 7 days.

The control group included 307 patients who underwent coronary bypass, valve surgery, or both at Baystate during January-June 2007.

The average age of all 618 patients was 67 years, 67% were men, 80% had hypertension, and 42% had diabetes. Two-thirds of all patients received a β-blocker during surgery, and 90% were on a β-blocker following surgery, Dr. James R. Cook and his associates reported.

During follow-up, the incidence of new-onset atrial fibrillation that required treatment was 24% in the patients treated with amiodarone and 34% in the control patients, a statistically significant difference, reported Dr. Cook, director of cardiac electrophysiology at Baystate, and his associates. Patients in the amiodarone group did not have an increased number of pulmonary complications, nor an increased need for pacemaker treatment.

The two groups were matched for all other peri- and postoperative outcomes studied, including their median ventilation time, the percentage with prolonged ventilation time, and the incidence of pneumonia. The median hospital length of stay was 9 days in the amiodarone group and 10 days for the controls. The mortality rate at 30 days after surgery was 5% in the amiodarone group and 4% in the control group.