2. Follow-up:
Recurrence: For patients with acute termination, the 1-year recurrence-free survival rate was 58.9% (95% CI 53.5%, 64.9%). For patients without acute termination, the 1-year recurrence-free survival rate was 49.0% (95% CI 37.9%, 63.4%). During the study, 58.4% had recurrent arrhythmic symptoms following ablation, not including the immediate blanking phase (90-day period). Index arrhythmia was terminated in most patients, but significant recurrent other atrial arrhythmias were noticed. AAFL is the most common form of arrhythmic recurrence, followed by AF. As the recurrence was assessed only by surface recording, it is difficult to discern whether it is due to the original or new arrhythmia mimicking the pattern. Based on the replication of morphology from pre-procedural flutter tracings, the recurrence of the targeted flutter is extremely low (2.7%). Ongoing follow-up beyond 1-year showed higher rates of recurrences. Recurrence is not due to recently ablated AAFL is the other useful finding.
Recurrences of new arrhythmia suggest progressive substrate changes from the native disease or additional new substrate due to the ablation. Utilizing linear lines to connect to electrically inert or anatomical barriers may influence the recurrence rate. Any non-transmural lesion in a linear line can become a substrate for reentrant arrhythmia. Assessing the block across a linear line is operator-dependent. Most of the block across a linear line was confirmed with a multipolar catheter time delay and or activation reversals. After the procedure, recovery of conduction across the line may contribute to recurrence.
Management of recurrent arrhythmias: The recurrences were managed by anti-arrhythmic drugs, electrical cardioversion, repeat ablation, or as the final resort, AV-node ablation. Repeat ablation was required in 35% of the cases. AV-Nodal ablation is the last resort in some patients (14.6%) who failed to achieve sinus rhythm despite the flutter ablation. Achieving sinus rhythm was difficult in a small number of patients, and they were counseled to accept that the arrhythmia was likely their new normal if the rate was under control.