Horowitz 1981.

Study characteristics
Methods	Parallel design (2 arms) Country: Australia Follow‐up period: 48 hours
Participants	Randomly assigned: N = 24 Lidocaine group: 50% (12/24) Mexiletine group: 50% (12/24) Age, years, mean (standard error) Lidocaine group: 60 (4) Mexiletine group: 59 (3) Gender, male, % (n/N) Lidocaine group: 75 (9/12) Mexiletine group: 75 (9/12) Inclusion criteria Suspected or proven acute myocardial infarction Ventricular tachycardia Ventricular fibrillation developing within 48 hours of onset of chest pain Exclusion criteria Evidence of atrioventricular conduction delay Supraventricular tachycardia Left ventricular failure Administration af any antiarrhythmic agent or β‐adrenoceptor antagonist in the preceding for 48 hours
Interventions	Lidocaine: 100 mg/bolus, infusion of 3 mg/min for 1 hour; thereafter, reduced to 2 mg/min after 1 hour Mexiletine: 200 mg/bolus, infusion of 1 mg/min for 1 hour; thereafter, reduced to 0.5 mg/min after 1 hour Co‐interventions: electroversion, bolus of mexiletine (200 mg) or lidocaine (100 mg) (page 410)
Outcomes	Ocurrence of complex ventricular tachyarrhythmia Comment: Trial did not assess the outcome explicitly
Notes	Sample size calculation a priori: not reported Sponsor: Austin Hospital Research Foundation Role of sponsor: support of the study Trial conduction dates: not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"... were randomised and allocated to receive..." (page 410) Insufficient information about the sequence generation process to permit judgement of ‘low risk’ or ‘high risk’
Allocation concealment (selection bias)	Unclear risk	Insufficient information about the allocation concealment process to permit judgement of ‘low risk’ or ‘high risk’ "Patients who had persisted multifocal ventricular extrasystoles or ventricular tachycardia or ventricular fibrillation... were given additional bolus of 200 mg of mexiletine or 100 mg of lignocaine" (page 410) This trial did not report whether the co‐intervention (additional bolus) was allocated concealment or not
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Insufficient information to permit judgement of ‘low risk’ or ‘high risk’
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Insufficient information to permit judgement of ‘low risk’ or ‘high risk’
Incomplete outcome data (attrition bias) All outcomes	Low risk	Withdrawal from study, % (n/N) Overall: 29.1 (7/24) Lidocaine: 25 (3/12) Mexiletine: 33 (4/12) Reasons Cardiogenic shock (mexiletine: 1) Pulmonary oedema (mexiletine: 2/lidocaine group: 2) 2:1 atrioventricular block (mexiletine: 1) Severe vomiting, nausea and confusion (lidocaine: 1)
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 (convincing text of this nature may be uncommon) Comment: This trial did report safety Quote: "the greater efficacy of mexiletine was not associated with increased drug toxicity" (page 409)
Other bias	High risk	Design bias and bias in presentation of data (Porta 2008)