Predictors of atrial flutter recurrence after atrial fibrillation ablation: the crucial role of structural and morphological left atrial remodeling

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Unrestricted Grant - Abbott Medical INTRODUCTION: Recurrence of supraventricular tachyarrhythmias after catheter ablation of atrial fibrillation (AF) is common, representing 30% of patients. Although AF recurrence occurs mostly, 10% of the patients face arrhythmia recurrence through atypical atrial flutter (AFL). The diagnostic and therapeutic management of atypical AFL is challenging. Predicting atypical AFL after AF catheter ablation is critical. PURPOSE: To identify morphological and structural predictors of recurrence in the form of atypical AFL compared to AF based on Late Gadolinium Enhancement Cardiac Magnetic Resonance (LGE-CMR). METHODS: – From January 2013 to December 2021, 56 patients facing post AF-CA atypical AFL were included in the monocentric and retrospective cohort. 112 patients with AF recurrence were randomly included in the cohort from the general database. Pre-procedure LGE-CMR was post-processed for every patient to assess global and regional left and right atrial (LA, RA) fibrosis quantification using an image intensity ratio > 1.32 as fibrosis. Sphericity was calculated as the percentage of similarity with respect to a sphere, and the volume of LA and RA were calculated. RESULTS: – 168 patients who had faced supraventricular arrhythmia recurrence after AF-CA were included in the monocentric retrospective cohort. They were mainly male (72.1%), with a median CHADS-VASc score of 1.4 +/- 1.3, a number of previous CA of 2,2 +/- 0.4, and a biatrial dilation (LA volume index of 53.5 ml/m2, RA volume index of 59.6 ml/m2). An age superior to 65 (OR=6.61, CI95%:2.18-14.41, p<0.01), the number of previous CA procedures (OR=3.03, CI95%:1.17-7.81, p=0.02), a history of management of invasive additional lines (OR=2.48, CI95%:1.01-6.27, p=0.05), an elevated LA sphericity (OR=1.33, CI95%:1.11-1.59, p<0.01) and an increased LA fibrotic burden (OR=1.03, CI95%:1.00-1.07, p=0.04) independently predicted the occurrence of atypical AFL compared with AF recurrence after AF-CA (Figure 1). Specifically, an increased amount of fibrosis in the lateral LA zone area (OR=1.03, CI95%:1.01-1.04, p<0.01)] was an independent predictor of recurrence in the form of atypical AFL compared with AF recurrence (Figure 2). CONCLUSION: The structural LA remodeling of AE, including LA fibrosis and LA sphericity, is a predictor of recurrence in the form of atypical atrial flutter compared with AF recurrence after AF-CA. [Figure: see text] [Figure: see text]