Predictors of recurrence after ablation of atypical atrial flutter: insights from a real-world cohort
S Azevedo, R Almeida Carvalho, I Coutinho Dos Santos, D Gomes, H Costa, D Matos, G Miguel Rocha Rodrigues, J Carmo, F Moscoso Costa, P Galvao Santos, P Carmo, D Cavaco, F Bello Morgado, P AdragaoAbstract
Background
Atypical atrial flutter (AAF) often occurs in patients with advanced atrial remodeling or following atrial fibrillation (AF) ablation, and its management remains challenging. Comparative evidence between pulsed field ablation (PFA) and radiofrequency (RF) energy in this setting is limited. Long-term effectiveness and factors predicting recurrence remain inadequately understood.
Methods
We retrospectively analyzed 91 consecutive patients who underwent catheter ablation of AAF between January 2023 and September 2025. Baseline variables included age, sex, body mass index (BMI), CHA2DS2-VASc score, left ventricular ejection fraction (LVEF), CT left atrial volume index (LAVi), and prior AF ablation. RF ablation was performed in 56 patients (61%), PFA in 32 (35%), and both modalities in 3 (3%). The primary outcome was recurrence during follow-up, defined as documented AAF or AF on ECG, Holter, or clinical record. Median follow-up was 13 months (IQR 6–21). Predictors of recurrence were assessed using Cox proportional hazards regression.
Results
Mean age was 70 ± 12 years; 42 (46%) were female. The mean CHA2DS2-VASc score was 3 ± 1, LVEF 53 ± 12%, CT LAVi 61±19ml/m² and BMI 27 ± 4 kg/m². A history of previous AF ablation was present in 42% of patients. Acute procedural success, defined as termination of the clinical atypical flutter during ablation or non-inducibility of any atrial tachycardia at the end of the procedure, was achieved in 77 patients (85%). During follow-up, primary outcome occurred in 27 patients (30%). In multivariate Cox analysis, use of PFA compared with RF (HR 3.29, 95% CI 1.41–7.67, p = 0.006) and higher CHA2DS2-VASc score (HR 1.58, 95% CI 1.15–2.17, p = 0.005) independently predicted recurrence.
Conclusions
In this contemporary cohort of AAF ablations the primary outcome occurred in approximately one-third of patients. Both the use of PFA and a higher CHA2DS2-VASc score were independently associated with increased recurrence risk. These findings underscore the influence of clinical substrate and energy source on mid-term outcomes and highlight the need for longer-term evaluation of PFA efficacy.