Comparison 4. Flecainide versus placebo or no treatment.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Withdrawals due to adverse effects – main analysis	1	73	Risk Ratio (M‐H, Fixed, 95% CI)	15.41 [0.91, 260.19]
2 Proarrhythmia – main analysis	4	511	Risk Ratio (M‐H, Fixed, 95% CI)	4.80 [1.30, 17.77]
3 Proarrhythmia – sensitivity analysis: persistent atrial fibrillation	2	435	Risk Ratio (M‐H, Fixed, 95% CI)	6.35 [0.91, 44.22]
4 Proarrhythmia – sensitivity analysis: low risk of bias studies	2	435	Risk Ratio (M‐H, Fixed, 95% CI)	6.35 [0.91, 44.22]
5 Proarrhythmia – sensitivity analysis: studies > 200 participants	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
6 Stroke – main analysis	1	362	Risk Ratio (M‐H, Fixed, 95% CI)	2.04 [0.11, 39.00]
7 Stroke – subgroup analysis: persistent atrial fibrillation	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
8 Stroke – sensitivity analysis: low risk of bias studies	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
9 Stroke – sensitivity analysis: studies > 200 participants	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
10 Atrial fibrillation recurrence – main analysis	4	511	Risk Ratio (M‐H, Fixed, 95% CI)	0.65 [0.55, 0.77]
11 Atrial fibrillation recurrence – sensitivity analysis: persistent atrial fibrillation	2	435	Risk Ratio (M‐H, Fixed, 95% CI)	0.71 [0.60, 0.85]
12 Atrial fibrillation recurrence – sensitivity analysis: low risk of bias studies	2	435	Risk Ratio (M‐H, Fixed, 95% CI)	0.71 [0.60, 0.85]
13 Atrial fibrillation recurrence – sensitivity analysis: studies > 200 participants	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only