Predictors of outcome after catheter ablation of atypical atrial flutter

Background Atypical atrial flutter (AAFL) is a macro–reentrant supraventricular tachycardia independent of the cavotricuspid isthmus, typically associated with atrial scar zones or prior surgical incisions. Despite advances in electroanatomical mapping and ablation techniques, arrhythmia recurrence after AAFL ablation remains frequent, and predictors of long-term success are not well defined. Objective To identify clinical and procedural predictors of arrhythmia recurrence following catheter ablation of AAFL. Methods We conducted a prospective analysis of 101 consecutive patients who underwent AAFL ablation over a 3.5-year period at our center. Reentry circuits and critical isthmuses were localized and categorized into eight anatomical types: anterior wall, posterior wall, peri-mitral, roof-dependent, peri-incisional, pulmonary vein–associated, indeterminate, and other forms. Baseline clinical and procedural variables were collected. Univariable and multivariable logistic regression analyses were performed to identify independent predictors of recurrence. Results During follow-up, arrhythmia recurrence occurred in 27.8% of patients. The most common reentry localization was the left atrial anterior wall (36/101, 35.6%). Circuit localization was significantly associated with recurrence (p=0.03). On multivariable analysis, peri-mitral flutters (odds ratio [OR]=6.1, p=0.038) and pulmonary vein–associated AAFLs (OR=5.4, p=0.043) independently predicted recurrence. No demographic or general procedural variables showed predictive value. Conclusion In patients undergoing AAFL ablation, the anatomical localization of the reentry circuit is the primary determinant of long-term rhythm outcome. Peri-mitral and pulmonary vein–related circuits carry a substantially higher recurrence risk.