Materne 1985.

Methods	RCT, parallel design
Participants	Total number of randomized participants: 71 Inclusion criteria: elective CABG Exclusion criteria: left ventricular ejection fraction < 40%, previous treatment with amiodarone, major perioperative complication (MI, cardiac tamponade), use of another anti‐arrhythmic drug Type of surgery: elective CABG Baseline characteristics (acebutolol) Intervention group Age, mean (SD): 55.1 (± 7.6) years Gender, M/F: 28/4 Preoperative use of beta‐blockers, %: 65.6 Control group (standard care) Age, mean (SD): 57.9 (± 6.9) years Gender, M/F: 32/7 Preoperative use of beta‐blockers, %: 58.9 Country: Belgium Setting: single centre; hospital
Interventions	Intervention group (acebutolol) Randomized, n = 32; losses = 0; analysed, n = 32 (use of ITT analysis not reported) Details: initiated 24 h after surgery, 100 mg acebutolol IV or 600 mg orally during the 1st day, then 1200 mg/day orally. No end of the treatment period was specified Control group (standard care) Randomized, n = 39; losses = 0; analysed, n = 39 Details: standard care
Outcomes	Outcomes measured/reported by study authors: supraventricular arrhythmias (to include AF), ventricular extrasystoles, haemodynamic parameters Outcomes relevant to the review: AF
Notes	Funding/declarations of interest: not reported Study dates: not reported
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	High risk	Open‐label trial
Blinding of outcome assessors (detection bias) All outcomes	High risk	Open‐label trial
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	Low risk	Not detected