White 1984.

Methods	RCT, parallel design
Participants	Total number of randomized participants: 41 Inclusion criteria: undergoing CABG surgery Exclusion criteria: contraindications to beta‐blockers; 2nd‐ or 3rd‐degree atrioventricular block; resting sinus bradycardia < 56 bpm; diabetes mellitis; spontaneous hypoglycaemia; allergic rhinitis; bronchospasm of any cause; COPD; treatment with digitalis Type of surgery: elective CABG Baseline characteristics Intervention group (timolol) Age, mean (SD): 55 (± 9) years Gender, M/F: 17/4 Ejection fraction, mean (SD), %: 63 (± 11) Preoperative use of beta‐blockers, %: 100 Control group (placebo) Age, mean (SD): 56 (± 10) years Gender, M/F: 17/3 Ejection fraction, mean (SD), %: 62 (± 12) Preoperative use of beta‐blockers, %: 90 Country: USA Setting: single centre; hospital
Interventions	Intervention group (timolol) Randomized, n = 21; losses = 0; analysed, n = 21 (use of ITT analysis was not reported) Details: existing beta‐blocker therapy stopped at least 12 h before surgery; timolol 0.5 mg diluted in 10 mL saline, given IV over 1 min twice daily starting 3‐7 h after surgery. When oral medication could be given, timolol 10 mg was given twice daily for 7 days Control group (placebo) Randomized, n = 20; losses = 0; analysed, n = 20 (use of ITT analysis was not reported) Details: placebo given same as intervention group
Outcomes	Outcomes measured/reported by study authors: supraventricular tachyarrhythmias (to include AF), mortality, death due to cardiac causes (MI) Outcomes relevant to the review: AF, mortality
Notes	Funding/declarations of interest: primary author supported by Odlin Research Fellowship of the Royal Australasian College of Physicians 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	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	Low risk	Not detected