Abstract
OBJECTIVE: To explore the feasibility of continuous low-dose isoproterenol (ISP) in identifying atrial fibrillation (AF) triggers under conscious sedation and to investigate the association between unmappable triggers and postablation recurrence. METHODS: In 50 PAF patients (Group 1), standardized ISP infusion (2-4 μg/min) was administered to provoke triggers, followed by adenosine triphosphate (ATP) challenge (30-40 mg) if no arrhythmia was induced. A matched control cohort (n = 96, Group 2) was selected based on baseline characteristics. Pulmonary vein isolation (PVI) was performed in all patients. Those with mappable triggers underwent additional ablation based on triggers. Additional ablation for other patient was guided by operators' discretion. RESULTS: In Group 1, provocative testing identified mappable triggers in 35 patients (Group 1A: 34 PV triggers and 10 non-PV triggers) and unmappable triggers in 5 (Group 1B), with 10 patients showing no inducible arrhythmia (Group 1C). After 12-month follow-up, Group 1B showed significantly higher recurrence than all other groups (60.0% vs. Group 1A: 5.7%, Group 1C: 0%, and Group 2: 14.6%; p < 0.05). CONCLUSIONS: Continuous low-dose ISP challenge provides a pragmatic approach for intraprocedural AF trigger identification, particularly under conscious sedation. The high recurrence rate in patients with unmappable triggers underscores the imperative for advanced mapping modalities to precisely localize arrhythmogenic foci origins.