Babin‐Ebell 1996.

Methods	RCT, parallel design
Participants	Total number of randomized participants: 70 Inclusion criteria: scheduled for CABG Exclusion criteria: unstable angina, bradycardia (HR < 50 bpm), COPD, ejection fraction < 0.4, history of SVT and additional surgical procedures Type of surgery: elective CABG Baseline characteristics Intervention group (propranolol) Age, mean (SD): 61.4 (± 8.7) years Gender, M/F: 25/8 NYHA class II/III, n: 13/20 History of myocardial infarction, %: 57 History of hypertension, %: 66 Preoperative use of beta‐blockers, %: 61 Control group (standard care) Age, mean (SD): 64.3 (± 9.1) years Gender, M/F: 31/6 NYHA class II/III, n: 10/27 History of myocardial infarction, %: 35 History of hypertension, %: 49 Preoperative use of beta‐blockers, %: 65 Country: Germany Setting: hospital; single centre
Interventions	Intervention group (propranolol) Randomized, n = 33; losses = 8 (withdrawal owing to: hypotension 5; bradycardia 1; perioperative MI 1, SVT 2); analysed, n = 33 (ITT analysis not used by study authors; we re‐included data where possible), n = 27 for supraventricular arrhythmias Details: 10 mg propranolol every 6 h postoperatively, up to 72 h Control group (standard care) Randomized, n = 37; losses = 14 (withdrawal owing to: MI 1; SVT 13); analysed, n = 37 Details: no anti‐arrhythmic agents were administered, up to 72 h
Outcomes	Outcomes measured/reported by study authors: supraventricular tachycardia, haemodynamic parameters, cardiac enzyme levels, use of catacholamines (to manage low cardiac output, or hypotension) and leading to withdrawal from treatment, MI, bradycardia. Outcomes were assessed up to 7 days following surgery Outcomes relevant to the review: acute MI, bradycardia
Notes	Funding/declarations of interest: not reported Study dates: not reported Note: study includes a 3rd arm (diltiazem), which we did not include in the review study authors reported data for supraventricular tachycardia at 2 time points. At the final time point (7 days), 1 participant in the control group developed supraventricular tachycardia; we did not include this in analysis of the earlier time point because we could not be certain whether this introduced a unit of analysis error
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	High risk	6 participants were excluded from analysis of supraventricular arrhythmias ‐ we re‐included these lost participants for data for bradycardia, hypotension, MI). Losses are imbalanced between groups
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