Role of diagnosis-to-ablation time in paroxysmal atrial fibrillation: preliminary results of the MULTI AF trial

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Diagnosis-to-ablation time (DAT) has been already defined as a predictor of atrial fibrillation (AF) ablation outcome. AF promotes pathological atrial remodelling at electrical, cellular, and structural levels. The aims of this study were to determine the role of DAT in atrial electrical remodelling and its impact on AF recurrencies. Methods Between January 2020 and February 2022, 122 patients (62% male, age 63.5±10.8 y) underwent pulmonary veins isolation (PVI) for paroxysmal atrial fibrillation in 7 Italian centres. For each patient, a high-density bipolar voltage map (BVM) of the left atrium (LA) was acquired by sequential multielectrode mapping in sinus rhythm through the Pentaray™ Catheter and the CARTO3® mapping system. More than 200 voltage points per map were acquired in different segments of the LA (posterior, anterior, lateral, superior, septal and inferior ). The procedural endpoint was PVI by circumferential ablation around the pulmonary vein antra. On top of PVI no "adjunctive" ablations, were performed. All patients were monitored as outpatients for AF recurrence. Results For the 122 patients enrolled the mean DAT was 37.6±35.2 months. Two groups were identified according to DAT: 51 patients in Group A with DAT ≤ 12 months and 71 patients in Group B with DAT > 12 months. The two groups have similar clinical, electrocardiographic and echocardiographic characteristics. Intraprocedural pulmonary vein isolation was achieved in all patients. At the high-density left atrial BVM a concealed electrical remodelling was detected in group B in each LA segment (Fig.1), with the mean global LA voltage amplitude significantly lower in patients with DAT>12 months (group A 2.32±0.81 mV vs group B 1.47±0.74 mV, p<0.01). After a median follow-up of 11.9±9.4 months, 14 patients (11.4%) had AF recurrencies following the first ablation procedure. A significant lower rate of AF recurrence was found among patients with DAT < 12 months (Fig. 2): 2 patients in group A vs 12 patients in group B (4% vs 18.2%, p<0.01). Conclusion Patients with paroxysmal atrial fibrillation with DAT>12 months have significantly lower bipolar LA voltages, revealing a concealed atrial remodelling. Furthermore, DAT>12 months is associated with poor AF ablation outcome.