Study objectives: Atrial fibrillation (AF) is a common
occurrence after cardiac surgery (10 to 53%) that contributes to
increased length of stay and hospital cost. Recent evidence suggests
that treatment with amiodarone may provide safe and effective
prophylaxis against AF in many patients undergoing cardiac operations.
This study sought to investigate whether oral amiodarone administered
postoperatively would reduce the incidence of postoperative AF.
Design: Prospective nonrandomized cohort study.
Patients and participants: In this prospective study, 1,196
consecutive patients who underwent various open-heart procedures with
cardiopulmonary bypass between July 1999 and February 2000 received
oral amiodarone, 400 mg bid, from the transfer to the cardiovascular
recovery room until the day of hospital discharge, or up to 7 days
postoperatively. The incidence of AF in this group of patients was
compared with a group of 1,246 patients who underwent cardiac surgery
with cardiopulmonary bypass in the preceding 8-month period (November
1998 to June 1999) at the same institution without receiving amiodarone
Setting: Tertiary health-care
Measurement and results: AF developed in 294
patients (25%) in amiodarone-treated group and in 385 patients (31%)
in the control group (p = 0.001). In multivariate logistic regression
analysis, oral amiodarone treatment emerged as an independent predictor
of lower risk of AF (odds ratio, 0.7; 95%; 95% confidence interval,
0.6 to 0.9; p = 0.002) and shorter hospital length of stay (odds
ratio, 0.8; 95% confidence interval, 0.5 to 0.9; p = 0.006).
Conclusions: Postoperative oral amiodarone treatment is a
safe and effective regimen associated with a reduced incidence of
new-onset AF and decreased length of hospital stay. Prospective
randomized trials are needed to evaluate the benefits of amiodarone
treatment relative to its side effect profiles.