Fourteen RCTs (n=2,864) were included.
Eleven of the 14 RCTs were double-blind, but only four concealed allocation. Six studies included intention-to-treat analyses. Four studies were funded by foundations or public sources and three were partially funded by pharmaceutical manufacturers. Scores for the internal validity assessment ranged from 14 (31%) to 38 (94%), with a mean of 24.4 (54%), out of a possible score of 45. Studies that had less potential for bias demonstrated a slightly greater drug effect than those with more potential, although the difference was not statistically significant. Trials with more potential for bias appeared to contain more error variance, but the pooled findings did not appear to be biased by the study methods.
Amiodarone reduced the incidence of AF by 51% in comparison with placebo (OR 0.49, 95% CI: 0.41, 0.59, p<0.001).
Differences in the odds of developing AF post-operatively were not statistically significant between the low-, medium- and high-dose groups: OR 0.58 (95% CI: 0.44, 0.77) for the low-dose group (<3,000 mg; 6 studies), 0.45 (95% CI: 0.30, 0.69) for the medium- dose group (3,000 to 5,000 mg; 4 studies) and 0.44 (95% CI: 0.33, 0.58) for the high-dose group (>5,000 mg; 4 trials).
Pre- versus post-operative initiation of amiodarone.
There were no significant differences in patients in whom amiodarone prophylaxis was initiated pre-operatively and continued post-operatively (6 studies) compared with those in whom amiodarone prophylaxis was initiated post-operatively (8 studies), OR 0.50 (95% CI: 0.39, 0.63) and OR 0.48 (95% CI: 0.37, 0.63), respectively (p=0.862).
Heterogeneity amongst all the included trials was not significant. The funnel plot showed no evidence of publication bias.