Bert 2001.

Methods	RCT, parallel design
Participants	Total number of randomized participants: 131 Inclusion criteria: scheduled for primary CABG surgery Exclusion criteria: history of atrial or ventricular arrhythmias or any other than sinus rhythm on ECG obtained evening before surgery; severe left ventricular dysfunction, bronchospastic airway disease, renal failure Type of surgery: elective CABG Baseline characteristics Intervention group (propranolol) Age, mean (SD): 63.8 (± 10.7) years Gender, M/F: 54/17 Ejection fraction, mean (SD), %: 49 (± 10) Preoperative use of beta‐blockers, %: 76.1 Control group (standard care) Age, mean (SD): 63.6 (± 9.6) years Gender, M/F: 50/10 Ejection fraction, mean (SD), %: 49 (± 11) Preoperative use of beta‐blockers, %: 71.7 Country: USA Setting: single centre; hospital
Interventions	Intervention group (propranolol) Randomized, n = 71; losses = 0; analysed, n = 71 (use of ITT analysis not used) Details:1 mg propranolol, IV, every 6 h initiated at start of ICU admission, continued until participant converted to oral propranolol, usually by 1st postoperative morning. Then 10 mg propranolol orally 4 times a day, until 4th postoperative day Control group (standard care) Randomized, n = 60; losses = 0; analysed, n = 60 Details: participants were given no antiarrhythmic drugs
Outcomes	Outcomes measured/reported by study authors: postoperative atrial tachyarrhythmias, time to extubation, MI, duration of hospital stay, mortality, ventricular ectopic activity Outcomes relevant to the review: MI, length of hospital stay, mortality
Notes	Funding/declarations of interest: not reported Study dates: not reported (study duration 36 months) Note: study includes 4 other groups (magnesium; magnesium + propranolol; digitalis; and digitalis + magnesium), which we did not include in the review 3 participants were not included after enrolment because they did not have surgery. We did not include these participants in the randomized participants
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Table of random numbers
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	Low risk	Quote: "All arrhythmia tracings were reviewed by a cardiologist unaware of the patient's treatment group to confirm arrhythmia classification and to quantify the initial ventricular response rate"
Incomplete outcome data (attrition bias) All outcomes	Low risk	We noted that 3 participants were excluded after enrolment because they did not undergo surgery; study authors did not report to which group these participants belonged. All other participants were included in analysis
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	High risk	The study end‐point was reached if a participant had postoperative atrial tachycardia. At this point, clinicians were free to treat participants with other agents to include beta‐blockers. Because participants in the control group may have received beta‐blockers, this may influence data for other outcomes