Timing of clinically relevant recurrence or true blanking period?

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The Ministry of Health and Welfare of Korea The National Research Foundation of Korea (NRF) which is funded by the Ministry of Science, ICT & Future Planning (MSIP) BACKGROUND: Although early recurrence (ER) within 3 months after atrial fibrillation catheter ablation (AFCA) is reportedly considered as a reliable predictor of late recurrence (LR), those ERs are still counted as benign events. There is no large-scale study showing the time limit of true blanking period, nor the potential mechanisms of clinically relevant recurrences within 3 months. PURPOSE: To explore temporal association of ERs with LRs and the presence of extra-pulmonary vein (ExPV) triggers. METHODS: This retrospective, single center study included 2,788 patients undergoing de novo AFCA (median 60 years old, 37.4% persistent AF [PeAF]) with isoproterenol provocation at the procedures. ER and LR were defined as any documented atrial arrhythmia >30s occurring (≤3 months), (>3months) after AFCA respectively. We evaluated the risk factors for ER and LR and compared the risk for LR and existence of ExPV triggers according to different timing of ER. RESULTS: ER was detected in 783 (28.1%) patients. During a median follow-up of 40 months, LR occurred in 945 (33.9%) patients. PeAF (OR 1.79, 95% CI 1.36-2.34), a larger left atrial (LA) diameter (OR 1.03 per 1 mm increase, 95% CI 1.00-1.05), and the existence of ExPV-triggers (OR 3.02, 95% CI 2.08-4.38) were independently associated with ER. ER (HR 2.55, 95% CI 2.15-3.03); the existence of ExPV-triggers (HR 1.63, 95% CI 1.28-2.08), PeAF (HR 1.39, 95% CI 1.16-1.66), and a larger LA diameter (HR 1.02 per 1 mm increase, 95% CI 1.01-1.04) were independent predictors for LR. When stratified according to the days of ER occurrence, ER occurring earlier showed trends toward higher rates of LR (P for trend=0.047) (Figure 1A). Patients with ER occurring within 1 month after AFCA had a higher incidence of LR than those with ER occurring between 2 and 3 months after AFCA (57.5% vs. 49.6%; log-rank P=0.020) (Figure 2B). ER occurring within 1 month after AFCA, compared with no ER, was independently associated with the existence of ExPV triggers (OR 3.99, 95% CI 2.65-6.02) whereas ERs occurring at different timing were not (Figure 1B). CONCLUSIONS: ER, regardless of the timing, and the existence of Ex-PV triggers were independently associated with long-term AF recurrence. Especially, ER occurring earlier within 1 month after AFCA, which was associated with Ex-PV triggers, had the worst rhythm outcome. [Figure: see text] [Figure: see text]