Baker 1971.

Study characteristics
Methods	Parallel design (2 arms) Country: England Follow‐up period: 48 hours
Participants	Enrolled: 91 Randomly assigned: N = 44 (acute myocardial infarction within 48 hours before admission) Lidocaine group: 47.72% (21/44) Placebo (5% dextrose solution) group: 52.27% (23/44) Age, % (n/N) Lidocaine group (≥ 50 years): 61.9 (13/21) Placebo (5% dextrose solution) group (≥ 50 years): 65.21 (15/23) Gender, male, % (n/N) Lidocaine group: 76.19 (16/21) Placebo (5% dextrose solution) group: 86.95 (20/23) Inclusion criterion: patients with acute myocardial infarction Exclusion criteria Heart rate < 60/min Hepatic disease
Interventions	Lidocaine: continuous infusion of 1.5 mg of lidocaine per minute in 5% dextrose solution Placebo: 5% dextrose solution: continuous infusion alone at same speed as intervention Co‐intervention: "additional lidocaine, either as bolus injection or as increased infusion doses, was given to four patients" (page 53)
Outcomes	Mortality Incidence and types of dysrhythmias
Notes	Sample size calculation a priori: not reported Sponsor: not reported Trial conduction dates: not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"...numbered according to a randomized sequence" (page 2) Insufficient information about the sequence generation process to permit judgement of ‘low risk’ or ‘high risk’
Allocation concealment (selection bias)	Unclear risk	"... cards in sealed envelopes number ..." (page 2) Insufficient information to permit judgement of ‘low risk’ or ‘high risk’
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	" a double‐blind trial" (page 1) Insufficient information about the blinding level process to permit judgement of ‘low risk’ or ‘high risk’
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Insufficient information about the blinding level process to permit judgement of ‘low risk’ or ‘high risk’
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	The report gave the impression that no dropouts or withdrawals had occurred, but this was not specifically stated
Selective reporting (reporting bias)	Low risk	The study protocol is not available, but it is clear that published reports describe all expected outcomes, including those that were pre‐specified
Other bias	High risk	Design bias (Porta 2008)