Catheter Ablation -> Atrial Fibrillation & Atrial Flutter: -> Mapping & Imaging D-PO01 - Featured Poster Session (ID 11) Poster

D-PO01-187 - Unidirectional Block Does Not Exist After Radiofrequency Line Creation : Data From Ultra-high-density Mapping (the Uniblock Study) (ID 133)

 S. Bun: Nothing relevant to disclose.
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Background: Whether unidirectional conduction block (UB) can be observed after creation of a radiofrequency (RF) line is still a subject of debate. Previous study reported a prevalence of 9 % of UB, but the assessment was performed using a point-by-point recording across the line, which may have artificially increased this UB percentage.
Objective: We conducted a prospective study, with assessment of bidirectional block using ultra-high-resolution (UHR) system after RF line creation.
Methods: Prospective patients admitted for an RF ablation procedure were included in this study. UHR maps were performed by pacing on both sides of the line created.
Results: A total of 18 maps were created in 8 patients (5 men, mean age 71.5 ± 10) by pacing (mean cycle length 600 ± 80 ms) from both sides of the line after a mean waiting time of 60 ± 18 min: 2 left atrial roof and 7 cavotricuspid isthmus lines; mean number of 4863 ± 3982 electrograms (381 ± 651 beats) acquired during 10 ± 9 min; mean right or left atrial volume 81 ± 82 mL. The RF lines were all unambiguously blocked bidirectionally. After a mean follow-up of 12 ± 4 months, no patient experienced any arrhythmia recurrence.
Conclusion: UHR mapping confirmed that the presence of a conduction block along an RF line is always associated with a block in the opposite direction.