Vitolo 1981.

Methods	RCT Open‐label Loss to follow‐up reported: yes
Participants	Any persistent AF (mean duration: NS). n = 54 Men: 37% Age (mean): 53 (SD 11) years Structural heart disease: 100%. LAD: NS. LVEF: NS
Interventions	Amiodarone 400 mg/day vs quinidine 1.2 g/day Method of AF cardioversion: electrical Warfarin discretionary
Outcomes	At 6 months: Mortality Proarrhythmia Adverse effects AF recurrence
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random numbers table.
Allocation concealment (selection bias)	Unclear risk	Method of concealment not described.
Blinding (performance bias and detection bias) All outcomes	High risk	Open‐label study.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No participant was loss to follow‐up in this small study.
Selective reporting (reporting bias)	Low risk	All prespecified outcomes of interest and all expected outcomes were reported.
Other bias	Low risk	No other bias apparent.

AF: atrial fibrillation; AFl: atrial flutter; LAD: left atrium diameter; LVEF: left ventricle ejection fraction; n: number of participants included in the study; NS: not stated; RCT: randomised controlled trial; SD: standard deviation.