Martin Fiala

Background: There is a limited knowledge on atrial arrhythmias recurring after complex left atrial (LA) pulsed field ablation (PFA) for longstanding persistent atrial fibrillation (LSPAF). Purpose: To present recurrent atrial arrhythmias and their sources found at repeat ablation following PFA for LSPAF. Methods and results: Of 214 patients with LSPAF (age 65±8, 53 females, continuous AF for 30±27 months) with complex LA PFA (Farapulse) in 10/2021-10/2023, 19 patients (64±8 years, 5 females) underwent repeat ablation for recurrent AF or arial tachycardia (AT) in 20 procedures. First PFA procedure included pulmonary vein isolation (PVI), roof/posterior wall, and mitral isthmus/coronary sinus/Ligament of Marshal region (LOM) ablation. At repeat ablation, 3D activation and entrainment mapping and ablation identified the AF/AT sources; ATs sources were classified as macroreentry (MRAT) (perimitral, roof-dependent, typical flutter) or localized (LOCAT) in case of smaller reentry or ectopic origin. Results: The clinical recurrent arrhythmias included paroxysmal AF (n=1), persistent AF (n=2), paroxysmal AT (n=1) or persistent AT (n=16). At the onset of repeat ablation, persistent AF/AT was present (n=15) or had to be induced (n=5). AF was finally present during the procedure in 8 patients, and was terminated by ablation directly into SR (n=3) or into intermediate AT (n=3) (conversion sites included LA ridge/LOM region 2x, RA septum 1x, RA low lateral 2x, CTI 1x), or required DCC (n=2). Primary recurrent or from AF converted AT was present in 15 patients; only MRAT in 6 patients, only LOCAT in 3 patients, and both AT types in 6 (patients). Of MRAT (N. ATs = 16), there were 12 perimitral ATs, 0 roof-dependent AT, and 2 typical flutters. Of LOCATs, sources were located at LA anterior wall 4x, LA septum 2x, LA roof 1x, LA ridge/LOM 1x, persistent left vena cava 1x, and RA – para SA node 1x. Recurrent AF/AT sources were targeted by radiofrequency or PFA in 16 and 4 cases, respectively, all spontaneous and induced AF/AT were finally terminated into SR in 16 cases, subsequent noninducibility by atrial pacing up to 300 bpn was achieved in 13 cases, and recurrent AF/AT occurred in 3 patients. Conclusion: At repeat ablation PFA (Farapulse) for LSPAF, recurrent AT dominated over AF, MRAT slightly prevailed over LOCAT, mostly constituted by perimitral AT, while roof-dependent AT recurrence was reduced to zero. A majority of AF/AT sources were located outside prior PFA lesions at the LA anterior wall, septum and the right atrium.

Background: There is a limited knowledge on immediate and long-term efficacy of pulsed field ablation (PFA) for residual atrial tachycardia (AT) recurring after persistent atrial fibrillation ablation (AF). Purpose: To present immediate and medium-term outcome of PFA (Farapulse) for complex AT recurring after ≥1 radiofrequency ablation (RFA) of primary (longstanding) persistent AF. Methods: In 5/2022-10/2023, 81 patients (64±8 years, 19 females) underwent PFA for complex AT in 83 PFA procedures after prior RFA procedure(s); in first (n=21), second (n=33), third (n=23), fourth (n=5), or fifth (n=1) repeat ablation procedure, respectively. Mapping/ablation strategy was directed by the CS activation/entrainment to: 1) no 3D mapping and direct PFA in left atrium (n=67); 2) PFA directly after 3D LA mapping (n=9); 3) PFA following RFA after 3D LA mapping (n=7). AT sources were classified as macroreentry (MRAT) (perimitral, roof-dependent, typical flutter) or localized (LOCAT) in case of smaller reentry or ectopic origin. Results: At the procedure onset, persistent AT was present in 58 patients, in the remaining cases AT (n=21) or AF (n=4) were induced. AF eventually occurred at some time of procedure in another 10 patients and was terminated by ablation at LA ridge/CS/LOM region 8x, LA posterior wall 3x, LUPV 1x, RUPV 1x, and RA low lateral wall 1x. Only MRAT, only LOCAT, or both AT types were found at 34 (41%), 35 (42%), and 14 (17%) procedures, respectively. A total of 125 ATs was identified (1, 2, and 3 ATs in 52, 20, and 11 patients). MRAT (n=60) included 32 perimitral ATs, 20 roof-dependent ATs, and 8 typical flutters. LOCAT (n=65) included RUPV source (n=1), LA extraPV sources (n=59), and RA sources (n=5). SR was restored with a 5±7 PFA applications at the site of AF source, total of PFA deliveries was 71±27, and procedure and fluoroscopy times were and 89±37 and 9±5 minutes, respectively. In the 7 patients with initial ineffective 6, 6, 11, 5, 18, 10, and 2 minutes of RFA, the AT was converted into SR by subsequent 1, 4, 1, 13, 4, 24, and 20 PFA applications. All ATs were terminated and noninducibility was achieved in 82 (99%) and 74 (89%) procedures, respectively. In 52 patients with >3 month follow-up, 46 (88%) patients remain in stable SR (41 / 79%) off AAD); 3 and 3 patients have paroxysmal or persistent AT. Conclusion: PFA with catheter Farapulse can affect complex/epicardial AT sources resistant to RFA in prior or present ablation procedure; however, there is a certain discrepancy between high efficacy in AT terminating and medium-term clinical outcome.

Funding Acknowledgements: Type of funding sources: None. Background: Pulsed field ablation (PFA) is a promising method to reduce procedure time and improve ablation safety and efficacy in all types of atrial fibrillation (AF). Purpose: To present ablation approach and medium-term outcomes of PFA in all AF types. Methods: Between 9/2021-10/2022, PFA using Farawave catheter was performed in 250 patients (63±11 years, 65 females). Patients with paroxysmal AF were basically scheduled for simple pulmonary vein isolation (PVI) (Farawave, ICE), patients with longstanding AF (LSPAF) underwent complex left atrial (LA) PFA (Farawave, CS 10-pole catheter, ICE); ablation extent varied in persistent AF. Results: Paroxysmal AF (n=131; 115 ablated in SR), persistent AF (n=39; 11 ablated in SR), and LSPAF (n=64) were ablated with procedure times 58±20, 105±28, and 116±32 minutes, respectively, and fluoroscopy times 9±5, 14±7, and 17±7 minutes, respectively. Additional 16 patients underwent PFA for atrial tachycardia (AT). Ongoing AF was terminated by PFA in 13/16 (81%), 16/28 (57%), and 23/64 (36%) patients with paroxysmal AF, persistent AF, and LSPAF, respectively. In groups of paroxysmal AF ablated in SR, paroxysmal AF ablated in AF, persistent AF ablated in SR, persistent AF, and LSPAF, simple PVI was performed in 100%, 50%, 73%, 11%, and 0 patients respectively; and freedom from AF/AT was present in 86/99 (87%), 11/14 (79%), 7/10 (70%), 11/12 (92%), and 40/52 (77%) patients, respectively, of total 187 patients with follow-up ≥3 months (≥6 months in 139 patients). In 8 patients with repeat ablation post-PFA for paroxysmal AF (n=4), persistent AF (n=2), LSPAF (n=2), extra-PV AF/AT sources dominated in all groups. Complications included one tamponade with pericardiocentesis, and prolonged ST elevation with negative coronary angiography. Conclusion: PFA using Farawave catheter was associated with reduced procedure times and favourable medium-term outcome for all AF types. Early experience specifically suggests improved outcome after extensive LA ablation for persistent AF/LSPAF.

Funding Acknowledgements: Type of funding sources: None. Background: Benefits of pulsed field ablation (PFA) compared to radiofrequency ablation (RFA) are not known in patients with longstanding persistent atrial fibrillation (LSPAF). Purpose: To present interim procedural and short-term clinical results of an ongoing prospective randomized comparison of PFA vs. RFA in patients with LSPAF. Methods: In 9/2021-10/2022, 125 patients underwent catheter ablation for LSPAF using PFA (n=64, 69±8 years, 11 F, continuous AF 32±20 months) vs. RFA (n=61, 68±8 years, 17 F, continuous AF 29±23 months). PFA included pulmonary vein isolation (PVI) and extra-PV left atrial (LA) ablation. RFA included stepwise PVI, electrogram-guided LA ablation, CS isolation, and electrogram-guided right atrial ablation. Intermediate endpoints were PVI, mitral isthmus, LA roof and CTI blocks); sinus rhythm (SR) restoration by ablation was the desired procedural endpoint. Follow-up included 7-day ECG monitoring every 3 months during the first year, and every 6 months afterwards. Results: In groups PFA vs. RFA, procedure and fluoroscopy times were 116±32 vs. 204±44 minutes, and 17±5 vs. 8±2 minutes, respectively (both p30 s) was achieved in 38 (79%) vs. 23 (46%) patients. Conclusion: Interim results of ongoing comparison suggest procedure time reduction and improved AF/AT free survival after PFA as compared to RFA in patients with LSPAF.

Funding Acknowledgements: Type of funding sources: None. Introduction: Malignant arrhythmic storm (MAS) increases mortality more than three-fold according to current data. In the acute setting, besides resolving reversible causes, antiarrhythmics are the mainstay of treatment. The role of suppressing the local sympathetic nervous system activity, using stellate ganglion block (SGB) for example, is still being investigated. Purpose: To show short-term efficacy of SGB in suppressing the ventricular arrhythmia recurrence in MAS. To identify subgroups of patients with better clinical response after SGB. Methods: All consecutive patients with MAS, with standard treatment failure and ventricular arrhythmia recurrence, treated with ultrasound guided SGB, instilating 7ml of 0,5% Bupivacain. 58 MAS treated with SGB durin 2017 – 2020. There were 49 men (84,5%), average age 68,7 +/- 11,4, with average left ventricular EF 28,9 +/- 8,43%. There were 17 diabetics (29,3%). Results: When we compare the numbers of defibrillations for sustained ventricular tachycardia 48 hours before and 48 hours after SGB, being the primary therapeutic endpoint in MAS, we see a 96,7% reduction (p < 0,001). When we evaluate ventricular arrhythmias treated with both antitachycardia pacing and shocks, then we see 90% reduction (p < 0,001). The effect of SGB in ventricular arrhythmia suppression was statistically significant during the entire follow-up of 8 days. When we analyzed the cohort, looking for groups showing better response after SGB in terms of ventricular arrhythmia reduction, the only group showing statistical significance in this regard are patients with diabetes mellitus. Conclusions: In our cohort, stellate ganglion block is exceptionally effective in the treatment algorithm of malignant arrhythmic storm. SGB shows significantly higher efficacy in the subgroup of patients with diabetes mellitus. Abstract Figure. VA before and after BSG

Background: Guidelines for atrial fibrillation (AF) management recommend optimal activated clotting time (ACT) to monitor heparin administration during AF catheter ablation; however do not specify the type of ACT meter.

Purpose: Single center retrospective analysis of complications of catheter ablation for paroxysmal atrial fibrillation (PAF).

Background: Long-term efficacy of catheter ablation for atrial fibrillation (AF) greatly declines with time.

Left atrial (LA) volume (LAV) is used for the selection of patients with atrial fibrillation (AF) to rhythm control strategies. Calculation of LAV from the LA diameters and areas by two-dimensional (2D) echocardiography may result in significant error. Accuracy of atrial volume assessment has never been studied in patients with long-standing persistent AF (LSPAF) and significant atrial remodeling. This study investigated correlation and agreement between 2D echocardiographic (Simpson method) and electroanatomic (CARTO, Biosense Webster) left and right atrial (RA) volumes (LAVECHO vs. LAVCARTO and RAVECHO vs. RAVCARTO) in patients undergoing catheter ablation for LSPAF. The study enrolled 173 consecutive subjects (females: 21 %, age: 59±9 years). There was only modest correlation between LAVECHO (92±31 ml) and LAVCARTO (178±37 ml) (R=0.57), and RAVECHO (71±29 ml) and RAVCARTO (173±34 ml) (R=0.42), respectively. LAVECHO and RAVECHO underestimated LAVCARTO and RAVCARTO with the absolute bias (±1.96 standard deviation) of -85 (-148; -22) ml and -102 (-169; -35) ml, respectively, and with the relative bias of -48 (-75; -21) % and -59 (-88; -30) %, respectively (all P<0.000001 for their mutual difference). Significant confounders of this difference were not identified. In patients with LSPAF, 2D echocardiography significantly underestimated both LA and RA volumes as compared with electroanatomic reference. This disagreement was independent of clinical, echocardiographic and mapping characteristics.