Is cardioversion or ablation more effective for treating an atrial flutter?

Cardioversion/ablati: Cardioversion is used to treat individual episodes if they don't recurr frequency, if chronic or recurrent atrial flutter is present, then ablation attempts to prevent the rhythm from recurring long term hopefully permanently.

Ablation: They will both likely restore normal rhythm. A cardioversion is more of a reset than a cure for the problem. An ablation modifies the tissue in the heart so that it is very unlikely that the arrhythmia will recur. This is typically permanent.

Flutter: cardioversion does not cure it but ablation does in most cases.