Curtis 1991.

Study characteristics
Methods	Randomised clinical trial at a single site in the United States
Participants	31 participants hospitalised with recent acute myocardial infarction and with a positive initial exercise test (performed 1 to 2 weeks after myocardial infarction) were included in the trial Male:female = 16:12 Mean age = not described Exclusion criteria: left bundle branch block or left ventricular hypertrophy on ECG, if they refused, if they were unable to exercise due to weakness, deconditioning, or musculoskeletal problems. Patients were also excluded if they were unable to discontinue all antianginal therapy (nitrates, beta‐adrenergic blocking drugs, and calcium antagonists) before exercise testing, or if they could not safely undergo exercise testing due to postinfarction angina or persistent heart failure
Interventions	Experimental group: propranolol (240 mg/d) (n =19) Control group: placebo (n = 12) Co‐intervention: not described Excluded medication: antianginal drugs, nitrates, calcium antagonists, beta‐adrenergic blocking drugs for at least 24 hours before exercise
Outcomes	Outcomes: treadmill test using Bruce protocol Time point reported: not reported
Notes	Study authors were contacted at kirkwood_adams@med.unc.edu on 20‐06‐2017. No response was received Time from inclusion to randomisation was 1 to 2 weeks after myocardial infarction No useful data could be extracted from the study Study was funded by the American Heart Association, North Carolina Affiliate, Inc., and by a research grant from the General Clinical Research Centers branch of the Division of Research Resources, United States Public Health Service
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
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not described
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Electrocardiograms were interpreted independently by 2 separate cardiologists, blinded to treatment assignment from the randomised exercise tests, with disagreements, if any, resolved by discussion
Incomplete outcome data (attrition bias) All outcomes	High risk	2 (10.5%) participants from the experimental group and 1 (8.3%) from the placebo group were excluded from the trial
Selective reporting (reporting bias)	High risk	No protocol was found, and the trial did not report all‐cause mortality or serious adverse events
Other bias	Low risk	No other biases were found