Matangi 1985.

Methods	RCT, parallel design
Participants	Total number of randomized participants: 168 Inclusion criteria: scheduled for CABG surgery, preoperative use of beta‐blockers Exclusion criteria: ejection fraction 35% or less, no preoperative use of beta‐blockers, SVT, postoperative inotropic support, congestive heart failure, postoperative heart block, involvement in another study where propranolol was contraindicated, sick sinus syndrome, known reaction to propranolol Type of surgery: elective CABG Baseline characteristics Intervention group (propranolol) Age, mean (SD): 54.6 (± 9.3) years Gender, M/F: 67/15 Angina class I/II/III/IV/V: 1/7/37/34/3 History of MI, n: 41 History of hypertension, n: 41 Control group (standard care) Age, mean (SD): 55.7 (± 9.9) years Gender, M/F: 63/19 Angina class I/II/III/IV/V: 2/6/38/33/3 History of MI, n: 54 History of hypertension, n: 44 Country: New Zealand Setting: single centre; hospital
Interventions	Intervention group (propranolol) Randomized, n = 83; losses = 1 (owing to SVT); analysed, n = 82 (use of ITT analysis for some losses) Details: propranolol 5 mg every 6 h, initially via nasogastric tube and then orally, started postoperatively and continued until time of discharge Control group (standard care) Randomized, n = 85; losses = 3 (owing to SVT); analysed, n = 82 (use of ITT analysis for some losses, but not those relating to supraventricular arrhythmias) Details:standard care
Outcomes	Outcomes measured/reported by study authors: supraventricular arrhythmias (AF and atrial tachycardia), ventricular arrhythmias, ventricular premature beats, acute MI, mortality Outcomes relevant to the review: AF, ventricular arrhythmias, MI, mortality
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	Use of sealed envelopes. Insufficient information
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	In 4 participants, beta‐blocker therapy was discontinued because of side effects (low cardiac output, bronchospasm, nightmares) but were analysed according to ITT. 4 participants were excluded owing to clinical events specified in exclusion criteria; these participants were not included in analyses. However, loss is < 10%
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