Pulsed field ablation for atrial tachycardia following prior persistent atrial fibrillation ablation and resistant to radiofrequency energy

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND: There is a limited knowledge of immediate and long-term efficacy of pulsed field ablation for residual atrial tachycardia (AT) following (longstanding) persistent atrial fibrillation (AF) ablation and resistant to prior radiofrequency ablation (RFA). PURPOSE: To present immediate effects of PFA (Farapulse) in a series of patients with repeat ablation for residual atrial tachycardia (AT) resistant to prior RFA. METHODS AND RESULTS: In 5-11/2022, of 23 patients scheduled for PFA, 19 patients (64±7 years, 3 females) underwent PFA for left atrial (LA) AT resistant to RFA in first (n=4), second (n=11), third (n=3), and fourth (n=1) repeat ablation, respectively, after primary persistent AF ablation (4 patients were redirected to RFA for septal/right atrial AT source found by 3D mapping). At the procedure onset, persistent AT was ongoing (n=15) or was induced (n=4; AF induced and subsequently converted into AT in 3 patients). Mapping/ablation strategy was directed according to CS activation/entrainment to: 1) no 3D mapping and direct PFA (n=11); 2) PFA directly after 3D LA mapping (n=5); 3) PFA following RFA after 3D LA mapping (n=3). Total of 29 ATs was found (1,2, and 3 ATs in 12, 4, and 3 patients, respectively). Localized AT sources (n=16) dominated over macroreentry (MR) ATs (8 perimitral, 4 roof-dependent, 1 typical flutter). Only MR ATs, only localized ATs, and both MR+localized ATs were present in 7, 4, and 8 patients, respectively. All ATs were stopped with 5±9 PFA applications at the site of AT source and remained non-inducible. In 3 patients with initial ineffective RFA (6, 11, 6 minutes) within the same procedure, subsequent PFA terminated the AT with 1, 4, and 1 application respectively. Procedure and fluoroscopy times were 104±29 and 12±4 minutes, no complication occurred. CONCLUSION: PFA with catheter Farapulse can affect complex/epicardial AT sources resistant to RFA in prior or present ablation procedure.