Society of Cardiovascular Anesthesiologists

N-3 Fatty acids for the prevention of atrial fibrillation after coronary artery bypass surgery: a randomized, controlled trial.

Calo L, Bianconi L, Colivicchi F, Lamberti F, Loricchio ML, de Ruvo E, Meo A, Pandozi C, Staibano M, Santini M. Department of Cardiac Diseases, San Filippo Neri Hospital, Rome, Italy. J Am Coll Cardiol. 2005 May 17;45(10):1723-8.

Reviewer: Hong Liu, MD
UC Davis Health System
Sacramento, CA

Background: Postoperative atrial fibrillation (AF) is a common complication of coronary artery bypass graft surgery (CABG). There is growing clinical evidence that N-3 polyunsaturated fatty acids (PUFAs) have cardiac antiarrhythmic effects.

Objectives: The aim of this study was to assess the efficacy of preoperative and postoperative treatment with PUFAs in preventing the occurrence of AF after CABG. Methods: A total of 160 patients were prospectively randomized to a control group (81 patients, 13 female, 64.9 +/- 9.1 years) or PUFAs 2 g/day (79 patients, 11 female, 66.2 +/- 8.0 years) for at least 5 days before elective CABG and until the day of discharge from the hospital. The primary end point was the development of AF in the postoperative period. The secondary end point was the hospital length of stay after surgery. All end points were independently assessed by two cardiologists blinded to treatment assignment.

Results: The clinical and surgical characteristics of the patients in the two groups were similar. Postoperative AF developed in 27 patients of the control group (33.3%) and in 12 patients of the PUFA group (15.2%) (p = 0.013). There was no significant difference in the incidence of nonfatal postoperative complications, and postoperative mortality was similar in the PUFA-treated patients (1.3%) versus controls (2.5%). After CABG, the PUFA patients were hospitalized for significantly fewer days than controls (7.3 +/- 2.1 days vs. 8.2 +/- 2.6 days, p = 0.017).

Conclusions: This study first demonstrates that PUFA administration during hospitalization in patients undergoing CABG substantially reduced the incidence of postoperative AF (54.4%) and was associated with a shorter hospital stay.

Comments: Atrial fibrillation is the most common complication associated with CABG. It occurs in 1/3 of post-CABG surgery. In addition, postoperative AF imparts an increased risk for other major complications after cardiac surgery, while also prolonging hospital length of stay, and increasing costs. The issue of prevention of postoperative AF in cardiac surgery was addressed by a number of studies. Several agents, including beta-blockers, sotalol, and amiodarone were found to reduce the incidence of AF. Other drugs, such as digitalis, calcium antagonists, procainamide, quinidine, and propafenone did not show any beneficial effect. Surgical interventions (MAZE with energy ablation, reducing atrial size, preservation of the anterior fat pad, and off-pump CABG) have also reduced the incidence of post-op AF.

The use of PUFAs shown to reduce postoperative AF from 33.3% to 15.2% ((p = 0.013) and shortened hospital stay in this study. The scientific basis of such effect including: hyperpolarization of the resting membrane potential, increase of the current necessary to elicit an action potential, and increase of the phase 4 refractory period. These effects were found to be related to an inhibition of the sodium current I_Na, of the calcium current I_CaL, and, possibly, of the potassium currents I_K and I_to. These effects account for an increased electrical stability that may result in a significant protection against fibrillation, which has been actually demonstrated in vitro. In summary, N-3 Polyunsaturated fatty acid, a safe supplementation to all patients (without exclusion) undergoing isolated CABG, significantly reduced the occurrence of postoperative AF, with an effect that is similar to that obtained with beta-blockers, sotalol, and amiodarone.

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