Dy 1998.

Methods	RCT, parallel design
Participants	Total number of randomized participants: 135 Inclusion criteria: scheduled for isolated CABG Exclusion criteria: ejection fraction < 30%, prior atrial or ventricular arrhythmias, severe COPD, serum creatinine > 2.0, severe bradycardia Type of surgery: elective CABG Baseline characteristics not reported in abstract Country: USA Setting: not reported in abstract
Interventions	Intervention group (metoprolol) Randomized, n = 67; losses = 0; analysed, n = 67 (use of ITT analysis not reported) Details: metoprolol given after extubation until 24 h before discharge. No additional details Control group (placebo) Randomized, n = 66; losses = 0; analysed, n = 66 Details: no details. We assume that the placebo was given the same as the intervention drug
Outcomes	Outcomes measured/reported by study authors: AF (period of observation is unclear) Outcomes relevant to the review: AF
Notes	Funding/declarations of interest: not reported Study dates: January 1995‐May 1997 Notes: conference abstract. We attempted to contacted the study authors by email to request additional information or for a full‐text publication; this was unsuccessful study includes an additional group (flecainide) which we did not include in the review
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not specified
Allocation concealment (selection bias)	Unclear risk	Not specified
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Randomized, placebo‐controlled, double‐blind trial
Blinding of outcome assessors (detection bias) All outcomes	Unclear risk	Not specified
Incomplete outcome data (attrition bias) All outcomes	Low risk	No apparent losses
Selective reporting (reporting bias)	Unclear risk	Study authors did not report prospective clinical trial registration or publication of a protocol. It was not feasible to effectively assess risk of reporting bias
Other bias	Unclear risk	Limited detail in abstract. Not feasible to assess other risks of bias from this report