Ahlmark 1976.

Study characteristics
Methods	Randomised clinical trial at a single site in Sweden. Duration not mentioned
Participants	162 participants younger than 66 years admitted to the Medical Department of Falu Hospital with diagnosed myocardial infarction were included in the trial Male:female = 142:20 Mean age = 57 years Exclusion criteria: older than 66 years, contraindications to beta‐blockade: cardiac decompensation despite adequate therapy, bradycardia (heart rate < 50 per minute), atrioventricular block I to III (PQ > 0.24 seconds), bronchial asthma, labile insulin‐treated diabetes mellitus, serious mental disease
Interventions	Experimental group: alprenolol (400 mg/d) (n = 69) Control group: no intervention other than the co‐intervention (n = 93) Co‐intervention: digitalis, diuretics, antiarrhythmics Excluded medication: not described
Outcomes	Outcomes: death. sudden death, fatal + non‐fatal myocardial reinfarction Time point reported: 24 months
Notes	Email was not found 393 participants were originally randomised to 2 groups; however, 231 participants were excluded due to death, diagnosis not verified, contraindications, or foreign catchment area. Only 162 participants were followed up. When counting the total number of participants in each group, we considered death participants to be included in the total number of participants. The rest of the excluded participants were accounted for in 'best‐worst and worst‐best' analyses MACE was calculated and reported as a composite of 'non‐fatal reinfarction + sudden death (within 24 hours of symptom onset)' Funding was not described
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described
Allocation concealment (selection bias)	Unclear risk	Not described sufficiently, other than "Patients were randomly allocated to the alprenolol group or the control group at the time of admission to hospital"
Blinding of participants and personnel (performance bias) All outcomes	High risk	Open‐label trial
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not described
Incomplete outcome data (attrition bias) All outcomes	High risk	124 from the experimental group and 107 from the control group were withdrawn from the study after randomisation
Selective reporting (reporting bias)	Unclear risk	No protocol was found; however mortality was reported
Other bias	Low risk	No other biases were found