Abstract
Background: Data related
to electrophysiologic characteristics of atypical atrial flutter (AFL)
following atrial fibrillation (AF) ablation and its prognostic value on
repeat ablation success are limited.
Methods: We studied consecutive patients who underwent a repeat
left atrial (LA) ablation procedure for either recurrent AF or atypical
AFL, at least 3 months after index AF ablation, between January 2012 and
July 2019. The demographics, clinical history, procedural data,
complications, and 1-year arrhythmia-free survival rates were recorded
for each subject after the first repeat ablation.
Results: A total of 336 patients were included in our study.
Among these 336 patients, 102 underwent a repeat ablation procedure for
atypical AFL and 234 underwent a repeat ablation procedure for recurrent
AF. The mean age was 63.7 ± 10.7 years, and 72.6 % of patients were
male. The atypical AFL cohort had significantly higher LA diameters (4.6
vs. 4.4 cm, p=0.04) and LA volume indices (LAVi; 85.1 vs. 75.4
ml/m2, p=0.03) compared to AF patients at repeat
ablation. Atypical AFL patients were more likely to have had index
radiofrequency (RF) ablation (as opposed to cryoballoon) than recurrent
AF patients (98% vs. 81%, p=0.01). Atypical AFLs were roof-dependent
in 35.6% and peri-mitral in 23.8% of cases. Major complication at
repeat ablation occurred in 0.9 % of the total cohort. Arrhythmia-free
survival at one year was significantly higher in the recurrent atypical
AFL compared to the recurrent AF cohort (75.5 vs. 65.0 %, p=0.04).
Conclusion: In our series, roof-dependent flutter is the most
common form of atypical atrial flutter post AF ablation. Patients
developing atypical AFL after index AF ablation have greater LA
dimensions than patients with recurrent AF. The success rate of first
repeat ablation is significantly higher among patients with recurrent
atypical AFL as compared to recurrent AF after index AF ablation.