Long-term outcomes after catheter ablation for idiopathic atypical atrial flutter.

Background: Idiopathic atypical (non-cavotricuspid isthmus-dependent) atrial flutter (IAAFL) may be seen in patients without structural heart disease and without previous cardiac surgery or ablation.
Objective: This study sought to determine the patient characteristics, electrophysiologic and electroanatomic properties, and clinical outcomes after ablation in patients with IAAFL.
Methods: We retrospectively compared IAAFL patients with cavotricuspid isthmus-dependent AFL (C-AFL) patients undergoing catheter ablation. The primary outcome was a composite of death from cardiovascular causes, ischemic stroke, and hospitalization for worsening of heart failure.
Results: Of 180 patients who underwent catheter ablation for AFL, 89 were included in this study (22 IAAFL and 67 C-AFL). Electrophysiologic study showed significantly longer intra-atrial conduction time and lower atrial voltage during sinus rhythm in the IAAFL group compared with the C-AFL group. The atrial scar was observed in all 22 IAAFL patients, with the most common sites being the posterior or lateral wall of the right atrium in 10 (45.5%) and the anterior wall of the left atrium in 8 (36.4%). During 3.5 ± 2.8 years of follow-up, the composite primary end point occurred significantly more frequently in the IAAFL group (hazard ratio [HR], 3.45; 95% confidence interval [CI], 1.20-9.89; P = .015). In multivariable analysis, brain natriuretic peptide levels (HR, 1.01; 95% CI, 1.00-1.01, per 1 pg/mL; P = .01) and IAAFL (HR, 4.14; 95% CI, 1.21-14.07; P = .02) were independently associated with the primary outcome.
Conclusion: IAAFL in patients had distinct electrophysiologic features suggestive of atrial cardiomyopathy. These patients are at risk for development of cardiovascular adverse events after ablation.
Competing Interests: Disclosures The authors have no conflicts of interest to disclose.
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