Willems 2006.

Methods	Randomised by random number table
Participants	Included patients with:1) at least 2 failed attempts of an antiarrhythmic drug therapy for symptomatic AF episodes; 2) persistent AF lasting for at least 1 month documented by daily trans‐telephonic transmitted ECG. 62 patients were enrolled. 32 were arranged to PVI plus SM group, and 30 to PVI alone group. Age: 58.3+/‐11.8 years in PVI+SM group, and 60.1+/‐9.3 years in PVI alone group. % of male: unknown. Follow‐up:487 days (range from 429 to 570 days). Location: Hamburg, Germany.
Interventions	Pulmonary vein isolation plus additional substrate modification compared to PVI alone.
Outcomes	Complications
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Incomplete outcome data addressed	High risk	There were no patients withdrawn or lost to follow up.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	Low risk	Sequence was generated by randomised number table.