Early afterdepolarizations and electrical storm after cardioversion for atrial fibrillation

Key Teaching Points•Cardioversion of rapidly conducted atrial fibrillation can be followed by electric instability and repolarization abnormalities leading to torsades de pointes ventricular tachycardia, especially if sinus bradycardia and pauses occur after cardioversion. The mechanism is similar to the torsades de pointes and ventricular fibrillation that can occur early after atrioventricular nodal ablation in the context of previously rapidly contacted atrial fibrillation.•The reverse use-dependent effect of class III antiarrhythmic drugs also potentiates their proarrhythmic potential and the occurrence of torsades de pointes. Careful monitoring would be prudent when Ikr blockers are used, especially in this situation.•Temporary acceleration of the heart rate with pacing rather than isoprenaline may be necessary to avoid proarrhythmia and torsades de pointes in similar circumstances. •Cardioversion of rapidly conducted atrial fibrillation can be followed by electric instability and repolarization abnormalities leading to torsades de pointes ventricular tachycardia, especially if sinus bradycardia and pauses occur after cardioversion. The mechanism is similar to the torsades de pointes and ventricular fibrillation that can occur early after atrioventricular nodal ablation in the context of previously rapidly contacted atrial fibrillation.•The reverse use-dependent effect of class III antiarrhythmic drugs also potentiates their proarrhythmic potential and the occurrence of torsades de pointes. Careful monitoring would be prudent when Ikr blockers are used, especially in this situation.•Temporary acceleration of the heart rate with pacing rather than isoprenaline may be necessary to avoid proarrhythmia and torsades de pointes in similar circumstances.