Oral 2006.

Methods	Randomised controlled trial.
Participants	Patients with chronic atrial fibrillation. A total of 146 patients were randomised. 77 assigned to CPVA, while 69 assigned to control group. Age: 58+/‐8 years in control group, and 55+/‐9 years in CPVA group. % of male: 62/69 (90%) in control group, and 67/77 (87%) in CPVA group. Follow‐up: 12 months. Location: Ann Arbor, Michigan.
Interventions	Circumferential pulmonary vein ablation. Control group: 200mg of amiodarone orally per day at least six weeks after randomisation before transthoracic cardioversion.
Outcomes	Freedom from AF and atrial flutter in 1 year. Incidence of complications, changes in the diameter of the left atrium and the LVEF, changes in the severity of symptoms.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Insufficient detail was provided.
Allocation concealment (selection bias)	Unclear risk	B‐Unclear. The authors did not depict allocation concealment method.
Blinding	High risk	Blinding was not reported.
Incomplete outcome data addressed	High risk	There were no patients withdrawn or lost to follow up.
Adequate sequence generation	Unclear risk	It was not addressed.