Lamb 1988.

Methods	RCT, parallel design
Participants	Total number of randomized participants: 60 Inclusion criteria: scheduled for CABG surgery Exclusion criteria: history of arrhythmia, asthma, peripheral vascular disease, congestive cardiac failure, left ventricular ejection fraction < 0.4 Type of surgery: elective CABG Baseline characteristics Intervention group (atenolol) Age, mean (SD): 52.7 (± 7.8) years Gender, M/F: 27/3 NYHA score, mean (SD): 2.8 (± 0.8) History of MI, n: 18 Preoperative use of beta‐blockers, n: 16 Control group (standard care) Age, mean (SD): 57.1 (± 7.3) years Gender, M/F: 25/5 NYHA score, mean (SD): 3.0 (± 0.9) History of MI, n: 19 Preoperative use of beta‐blockers, n: 14 Country: UK Setting: single centre; hospital
Interventions	Intervention group (atenolol) Randomized, n = 30; losses = 0; analysed, n = 30 (use of ITT analysis not reported) Details: atenolol 50 mg, orally, daily treatment was started 72 h before surgery and was continued for 7 days Control group (standard care) Randomized, n = 30; losses = 0; analysed, n = 30 Details: standard care, no additional treatment
Outcomes	Outcomes measured/reported by study authors: supraventricular arrhythmias; AF 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