[Atrial flutter: from ECG to catheter ablation].

Recent advances in technology and clinical electrophysiology have led to precise characterization of re-entry circuits and effective ablation strategies of atypical atrial flutter. Combination of activation and entrainment mapping is the key to identifying the re-entry circuit. The presence of a slow-conducting isthmus, localized re-entry, dual-loop re-entry or bystander loops may lead to misleading activation maps but can be identified by electrogram analysis and entrainment mapping. The ECG pattern of atypical atrial flutter is poorly predictive of circuit anatomy but may still provide mechanistic insight. Long-term ablation success requires the creation of a transmural continuous lesion across a critical component of the re-entry circuit. Procedural endpoints include bidirectional conduction block across linear lesions and non-inducibility of atrial tachycardia.