The impact of abnormal conduction zone on outcomes after catheter ablation for atrial fibrillation. (14th October 2021) - Mine, T
Abstract: Background: The abnormal conduction zone (ACZ) in the left atrium (LA) has attracted attention as an arrhythmia substrate in atrial fibrillation (AF). Purpose: We investigated whether the ACZ affects outcomes after catheter ablation (CA) for AF. Methods: We studied 78 patients (42 Non-paroxysmal AF, 49 males, and 68±10 years) who received CA for AF. High-density LA mapping during high right atrial pacing was constructed gaining than 2000 points (average 4377±846 points). Isochronal activation maps created at 5-ms interval setting. ACZ was identified by locating a site with isochronal crowding of ≥3 isochrones, and ≥8 isochrones were defined as the conduction block zone (CBZ) in a 4-mm diameter tag (conduction velocity were calculated as ≤27 cm/s and≤10 cm/s, respectively). Result: Recurrent AF was detected in 25/78 patients (32%) during the follow-up period (9.2±3.0 month). ACZ and CBZ were distributed linearly, and ACZ was observed in 73 of 78 patients and 8 of these 73 patients had the CBZ. Univariate analysis revealed that elevated body mass index (26.2±3.8 vs. 24.3±3.3 kg/m 2, P=0.0303), the higher prevalence of non-paroxysmal AF (72% vs. 45%, P=0.0272), larger LA diameter (47.6±6.6 vs. 42.1±6.9 mm, P=0.0014), and longer length of ACZ (79.7±45.1 vs. 52.9±35.7 mm, P=0.0058) were associated with recurrent AF after CA. On multivariate analysis, longer ACZ was independently associated with recurrent AF. Moreover, patients with longer ACZ (cutoff value: 84 mm) had a higher risk of recurrent AF than shorter ACZ (12/22; 55% vs 13/56; 23%, log-rank P=0.0024). Conclusion: The length of ACZ was associated with recurrent AF after CA. Funding Acknowledgement: Type of funding sources: None.