Janssen 1986.

Methods	RCT, parallel design
Participants	Total number of randomized participants: 151 Inclusion criteria: scheduled for CABG surgery, with left ventricular ejection fraction at least 30% Exclusion criteria: preoperative MI, inotropic support with dopamine, postoperative death, severe sinus bradycardia, inappropriate data (no additional details) Type of surgery: elective CABG Baseline characteristics Intervention group (sotalol) Age, mean (range): 58 (31‐74) years Gender, M/F: 34/7 History of MI, n: 11 Intervention group (metoprolol) Age, mean (range): 57.5 (37‐68) years Gender, M/F: 31/8 History of MI, n: 16 Control group (standard care) Age, mean (range): 59.6 (39‐72) years Gender, M/F: 40/10 History of MI, n: 19 Country: Netherlands Setting: single centre; hospital
Interventions	Intervention group (sotalol) Randomized, n = unclear; losses = unclear; analysed, n = 41 (ITT analysis not used) Details: 1 h after surgery 0.3 mg/kg sotalol, IV. At 24 h postoperatively, 3 X 80 mg sotalol orally, daily, until hospital discharge Intervention group (metoprolol) Randomized, n = unclear; losses = unclear; analysed, n = 39 Details: 1 h after surgery 0.1 mg/kg metoprolol, IV. At 24 h postoperatively, 3 X 50 mg metoprolol orally, daily, until hospital discharge Control group (standard care) Randomized, n = unclear; losses = unclear; analysed, n = 50 Details: received no prophylactic therapy
Outcomes	Outcomes measured/reported by study authors: supraventricular tachycardias, atrial fibrillation Outcomes relevant to the review: AF, mortality
Notes	Funding/declarations of interest: not reported Study dates: October 1983‐January 1984 we could not be certain of the number of participants randomized to each group we combined data for the sotalol and the metoprolol groups
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not specified
Allocation concealment (selection bias)	Unclear risk	Use of sealed envelopes; no additional details
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	High risk	21 participants excluded from analysis (2 MI, 12 inotropic support after CABG, 1 death, 1 bradycardia, 5 inappropriate data). It is not clear to which group these participants belonged
Selective reporting (reporting bias)	High risk	We noted that study authors appeared to only report statistically significant results
Other bias	High risk	All participants were given beta‐blockers, if required, to treat supraventricular tachycardia. In the control group, 10 participants were given sotalol, and 4 participants were given metoprolol. This may influence outcome data for mortality