Left atrial flutter ablation had 92% acute success; recurrence was 24% at 1 year and 49% at 3 years, with 4-fold relapse risk if LVEF <40% and atrial scar outside shared isthmus coexist.
In patients undergoing atypical atrial flutter ablation, reduced LVEF (<40%) and atrial scar outside the shared isthmus are significant predictors of recurrence, increasing risk 4-fold when both are present.
Abstract Introduction In recent years, catheter ablation has become a promising treatment for patients with atypical atrial flutter (AFl), driven by advancements in technology and a deeper understanding of arrhythmia mechanisms. However, its long-term effectiveness and the factors predicting recurrence remain inadequately understood. Purpose To evaluate the efficacy of atypical AFl ablation and identify predictors of recurrence. Methods We conducted a single-center, retrospective study of consecutive patients who underwent left atrium AFl ablation. A systematic, predefined high-resolution mapping workflow was employed to characterize the mechanism of the arrhythmia and guide the ablation strategy. Clinical, echocardiographic, and AFl substrate and mapping characteristics were evaluated as risk factors for atrial arrhythmic relapse during follow-up, assessed using Cox regression and Kaplan-Meier survival analysis. Results From 2015 to 2024, 128 patients were included (mean age: 68 years, 58% male). Fifty-two percent had undergone previous pulmonary vein isolation, and previous left atrial linear ablation had been performed in 16%. Overall acute success was high, with 92% conversion to sinus rhythm after the first ablation set. However, AFl recurrence was 24% and 49% at 1 and 3 years, respectively. The only two predictors of arrhythmic relapse on univariate analysis were left ventricular ejection fraction (LVEF) 40% (HR 2.191, 95% CI: 1.124–3.870, p=0.007) and the presence of atrial scar outside the AFl shared isthmus (HR 1.997, 95% CI: 1.123-3.550). Strikingly, left atrial volume had no influence on arrhythmic recurrence. We then assessed the incremental impact of having none, one, or both of the identified risk factors. Having one of these criteria increased the risk of relapse (HR 1.259, 95% CI: 0.653-2.427, p=NS) and the presence of both increased the risk by 4-fold (HR 4.395, 95% CI: 2.135-9.049, p0.001). Conclusion Two key risk factors were identified for arrhythmic relapse after AFl ablation: reduced LVEF and the presence of left atrial scar outside the shared isthmus. Interestingly, the risk of atrial arrhythmic relapse increased 4-fold with the presence of both features, while left atrial volume had no impact on recurrences.Outcomes
Vilela et al. (2025) studied this question. Left atrial flutter ablation had 92% acute success; recurrence was 24% at 1 year and 49% at 3 years, with 4-fold relapse risk if LVEF <40% and atrial scar outside shared isthmus coexist.