A novel ablation approach in atrial fibrillation patients undergoing fibrotic-based substrate modification: Targeting the Bachmann's bundle?

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): ITN Networks PersonalizeAF: Personalized Therapies for Atrial Fibrillation. A Translational Approach, No. 860974; CATCH ME: Characterizing Atrial fibrillation by Translating its Causes into Health Modifiers in the Elderly, No. 633196; MAESTRIA: Machine Learning and Artificial Intelligence for Early Detection of Stroke and Atrial Fibrillation, No. 965286; AFib-TrainNet: EU Training Network on Novel Targets and Methods in Atrial Fibrillation, No. 675351 Netherlands Heart Foundation: CVON2014-09, RACE V Reappraisal of Atrial Fibrillation: Interaction between hyperCoagulability, Electrical remodeling, and Vascular Destabilization in the Progression of Atrial Fibrillation Background Few studies report on mechanisms leading to termination of atrial fibrillation (AF). Purpose To characterise electrophysiological parameters and conduction patterns during the transition from AF to sinus rhythm under various conditions of AF termination. Methods A retrospective evaluation of 6 goat studies was performed. AF was maintained for 3-4 weeks in 29 animals. Four animals were in SR. Unipolar electrograms were acquired with one 249-electrode array/atrium. Pharmacological termination of AF was evoked by various drugs; AP14145 (n = 5), PA6 (n = 7), XAF-1407 (n = 9) vernakalant (n = 8). In animals with sinus rhythm, AF was acutely induced and terminated spontaneously. Baseline AF and ≤3 recordings of the last 10 seconds preceding AF termination were analysed. Intervals with temporal continuous and periodic activity were distinguished in the recordings. AF cycle length (AFCL), conduction velocity and path length were determined for each interval. Results In total, 85 AF terminations were recorded. Switches between temporal continuous and periodic activity were seen frequently during AF. However, termination of AF was always preceded by a phase of periodic activity (PA). The final phase of PA persisted for a median number of 21 [IQR 10-28] cycles in the left atrium and somewhat shorter in the right atrium, Table 1. This final phase of PA was accompanied by a profound bi-atrial increase of AFCL, conduction velocity and path length and a disappearance of inter-atrial cycle length differences. Equipotent changes were not observed in the preceding PAs. During the final AF beats, the number of wave fronts were low, 1 or 2. Interestingly, 92% of the patterns during the last beats of AF involved the Bachmann’s bundle as main source of atrial conduction. Conclusion AF termination is preceded by an increased organisation of fibrillatory conduction, associated with abrupt prolongation of the path length. Propagation in atrial free walls regularly originated from the Bachmann’s bundle. These findings suggest that AF termination was not a random process but follows common spatiotemporal patterns. Final period of temporal organisation Left atrium Right atrium Final PA start Final PA end Final PA start Final PA end Af cycle length (ms) 163 ± 37 204 ± 50* 146 ± 44 207 ± 49* Conduction velocity (cm/s) 77 ± 15 96 ± 25* 83 ± 20 103 ± 24* Path Length (cm) 12.2 ± 2.7 19.3 ± 6.3* 12.0 ± 4.1 21.2 ± 6.4* Length of final periodic activity (beats) NA 21 [IQR 10-28] NA 15 [IQR 10- 25] Electrophysiological changes during the final period periodic activity (PA). Wilcoxon signed rank test. *p <0.05NA= not available

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A Randomized Trial of Pulmonary Venous Isolation Alone Versus Additional Substrate Modification as Treatment for Paroxysmal Atrial Fibrillation

Heart Lung and Circulation ◽

10.1016/j.hlc.2010.06.891 ◽

2010 ◽

Vol 19 ◽

pp. S95-S96

Author(s):

A. McGavigan ◽

J. Bowyer ◽

C. Singleton

Keyword(s):

Atrial Fibrillation ◽

Randomized Trial ◽

Paroxysmal Atrial Fibrillation ◽

Substrate Modification

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Abstract 20107: Randomized Comparison of Personalized versus Standardized Substrate Modification During Catheter Ablation for Symptomatic Atrial Fibrillation

Circulation ◽

10.1161/circ.132.suppl_3.20107 ◽

2015 ◽

Vol 132 (suppl_3) ◽

Author(s):

Simon Kircher ◽

Arash Arya ◽

David Altmann ◽

Sascha Rolf ◽

Andreas Bollmann ◽

...

Keyword(s):

Atrial Fibrillation ◽

Low Voltage ◽

Randomized Study ◽

Standard Group ◽

Linear Lesions ◽

Substrate Modification ◽

Arrhythmogenic Substrate ◽

Group 2 ◽

Group 1

Introduction: Pulmonary vein (PV) isolation forms the cornerstone of any ablation procedure for atrial fibrillation (AF). There is, however, no uniform strategy how to detect and target left atrial (LA) arrhythmogenic substrate outside the PV antra. Fibrosis that corresponds well to LA low-voltage areas (LVAs) seems to play a key role in AF arrhythmogenesis and might therefore be a suitable target for additional substrate modification (SM). Objective: The purpose of this prospective randomized study was to compare a novel technique for SM based on ablation of potentially arrhythmogenic LA LVAs with a standard approach consisting of empiric LA linear ablation. Methods: Patients (pts) with symptomatic paroxysmal or persistent AF were randomized to standard (group 1) or personalized (group 2) SM. Circumferential PV isolation was the primary step in both groups. In group 1, pre-defined linear lesions were applied at the LA roof and bottom, respectively, and at the mitral isthmus only in pts with persistent AF. In group 2, targets for SM (i.e. LVAs) were identified by detailed bipolar voltage mapping (BVM) during sinus rhythm irrespective of AF type. Peak-to-peak electrogram amplitudes were defined as “normal” (> 0.5 mV), as “low voltages” (0.2 to 0.5 mV), or as “scar” (< 0.2 mV). LVAs were targeted by tissue homogenization and / or strategic linear lesions. The primary endpoint was freedom from any atrial arrhythmia (i.e. AF, atrial flutter, or atrial tachycardia) > 30 seconds off antiarrhythmic drugs on serial 7-d-Holter ECG recordings after a follow-up period of 12 months. Results: In total, 124 ablation-naïve pts (mean age 63 ± 9 years, 62 % male, 49 % with persistent AF) were enrolled in this study. LVAs were present in 18 % of pts with paroxysmal and in 41 % of pts with persistent AF (p<0.05). At the end of the follow-up period, 25 out of 59 pts (42 %) in the conventional group were free from arrhythmia recurrence as compared to 40 out of 59 pts (68 %) in the BVM-guided group (unadjusted log rank p = 0.003). Conclusion: Personalized SM guided by endocardial BVM is associated with a higher success rate compared to a conventional approach applying empirical SM based on AF phenotype.

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Abstract 14616: Tailored Low Voltage Zones Ablation Using Contact Force Sensing Technology in Patients With Persistent Atrial Fibrillation (TWEET-AF): A Pilot Study

Circulation ◽

10.1161/circ.142.suppl_3.14616 ◽

2020 ◽

Vol 142 (Suppl_3) ◽

Author(s):

Gabriele DAmbrosio ◽

Santi Raffa ◽

Silvio Romano ◽

Markus Frommhold ◽

Obaida Alothman ◽

...

Keyword(s):

Atrial Fibrillation ◽

Contact Force ◽

Low Voltage ◽

Volume Index ◽

Success Rates ◽

Term Outcome ◽

Long Term Outcome ◽

Substrate Modification ◽

Sensing Technology ◽

Linear Ablation

Introduction: Although pulmonary vein (PV) isolation (PVI) is very effective in paroxysmal atrial fibrillation (AF), in patients (pts) with persistent AF, PVI often is not sufficient. Many studies suggested that low voltage zones (LVZs) outside of the PV might be involved in the complex mechanisms perpetuating AF. However ablation strategies involving substrate modification (SM) did not show additional benefits in persistent AF pts. Those studies were performed before the introduction of contact force technology, and the most likely explanation for these results could be the inability to achieve effective transmural lesions and continuous linear ablation. Hypothesis: We hypothesized that the use of contact force technology would improve ablation efficacy. Therefore, we analyzed the long-term outcome after two different ablation strategies in pts with persistent AF depending on whether there was evidence of LVZs in the left atrium or not. Methods: The presence of LVZs were defined as sites of >3 adjacent low-voltage points <0.5 mV during electrophysiology study. Depending on the location of the LVZ, linear ablation was performed. Catheter ablation was performed using TactiCath™ or SmartTouch™ ablation catheters aiming at contact values ≥10g <20g and FTI >400g/s. Ablation was performed in a temperature-controlled fashion with energy of 30W except at the posterior wall (20-25W). Results: 121 consecutive pts with persistent AF (46 female, median age 66 [59-72] years, mean duration of AF 16 [7-73] months, CT derived LA volume index 66 [56-75]ml/m2) were included: pts without LVZs underwent PVI alone (n = 74), in pts with LVZs, PVI + SM (n = 47) was performed (mitral Isthmus line in 2, supero-septal line in 39, and roof line in 47; bidirectional block was achieved in 100%, 97%, and 100%, respectively). After a median follow-up of 13 [6-21] months, 86% of pts without and 78% with substrate were in sinus rhythm, mainly without antiarrhythmic drugs (89% PVI only, 84% PVI + SM). Conclusions: In patients with persistent AF without LVZs, PVI alone leads to excellent 2-year freedom from AF. In pts with LVZs, additional substrate modification with CF sensing technology is associated with improved success rates compared to previous studies.

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