Results
Baseline characteristics in each group were similar (Table 1). Compared to patients undergoing stepwise linear ablation, patients undergoing LA PWI had a shorter procedure duration (220 min vs 190 min, p<0.001, respectively), shorter fluoroscopy time (34 min vs 17 min, p<0.001), a lower fluoroscopy dose (956 mGy vs 390 mGy, p<0.001), and a lower radiofrequency time (93 min vs 81 min, p=0.011) (table 2).
Single Procedure Outcomes
AF was terminated with ablation more frequently in the stepwise group compared to the LA PWI group (49% vs. 20%, p<0.001). There was similar freedom from any atrial arrhythmia >30s in duration after index ablation for both the stepwise and LA PWI groups at 12 months (69% vs. 78%, p=0.1), 24 months (60% vs. 71%, p=0.09), and 36 months (60% vs. 69%, p=0.1) (Figure 1). There was no significant difference between stepwise and LA PWI Kaplan-Meier estimated freedom from AF >30s alone at 12 months (88% vs. 87%, p=0.8), 24 months (87% vs. 81%, p=0.6), or 36 months (86% vs. 80%, p=0.5) (Figure 2). In contrast, stepwise patients were less likely to remain free from recurrent AT > 30s when compared to LA PWI patients at 12 months (71% vs. 87%, p=0.008), 24 months (66% vs. 85%, p=0.002), and 36 months (66% vs. 84%, p=0.003) (Figure 3). Stepwise group patients were over twice as likely to experience persistent AF or AT after index ablation at 36 months (29% vs 14%, p=0.005) (Figure 4).
Second Procedure Frequency and Outcomes
Stepwise patients more frequently underwent second catheter ablation within 36 months compared to LA PWI patients (32% vs. 11%, p<0.001) (Figure 5). Patients who experienced a persistent recurrent arrhythmia were nearly twice as likely to undergo second ablation when compared to patients that experience only paroxysmal arrhythmia recurrence (36 of 46; 78% vs 13 of 32; 40%, p=0.001). After a second ablation, there was a higher rate of recurrence of AF or AT in the stepwise group when compared to the LA PWI group (15% vs 4%, p=0.003). Patients who underwent stepwise ablation as an initial strategy were more likely to undergo a third ablation at 36 months (8 of 111; 7% vs 1 of 111; 1%, p=0.02).