Study designs of evaluations included in the review
Randomised controlled trials (RCTs) were eligible for inclusion.
Specific interventions included in the review
Studies of prophylactic magnesium sulphate, as a bolus or continuous infusion, given as a specified dose were eligible for inclusion. The comparison was with placebo or no intervention. The doses ranged from 7.5 to 25 g and the duration of treatment from 2 to 5 days. Some of the included studies excluded those taking amiodarone or beta-blockers, whereas in other studies between 23 and 69% of participants were taking beta-blockers concomitantly.
Participants included in the review
Studies of adults (aged 18 years or older) undergoing elective CABG, using on- or off-pump procedures, were eligible for inclusion. There was no limitation on the number of grafts or conduit types included. People with chronic or paroxysmal AF, or a history of any arrhythmias, were excluded. The mean age of the participants in the included studies ranged from 52 to 65 years. People with severe heart failure, renal failure, or re-do CABG were excluded from the included studies.
Outcomes assessed in the review
The primary outcome of interest was the incidence of AF following CABG. This was defined as totally irregular atrial rhythm measured using a continuous electrocardiogram (EEG) and confirmed by a standard lead EEG. Studies that did not specify the method of detection of AF, or the follow-up time, were excluded.
How were decisions on the relevance of primary studies made?
Two reviewers independently checked papers for inclusion in the review. Any disagreements were resolved by consensus.