Ablation of “Background Tachycardia” in Long Standing Atrial Fibrillation: Improving the Outcomes by Unmasking a Residual Atrial Fibrillation Perpetuator

Abstract

BackgroundDespite great progress, the long-term outcomes of catheter ablation for long standing atrial fibrillation (LSAF) remain suboptimal [1], [2] . Pulmonary vein isolation (PVI) [3], [4] is recognized as the cornerstone for paroxysmal atrial fibrillation (AF) ablation [5], [6], [7] but insufficient as a stand-alone ablation approach for LSAF [8], [9] .The adjunct of linear ablation lesion sets [10], [11], [12] ; ablation of complex fractionated atrial electrograms (CFAE) [13], [14] ; extensive ablation including the left atrial (LA) posterior wall [15] , superior vena cava (SVC) [16] , coronary sinus and LA appendage or even vagal denervation [17], [18] may improve outcomes slightly but compromises procedural complexity and safety [19], [20], [21] . We have found that the AF Nests (AFN) ablation had a favorable impact on the long-term outcome after a single procedure [22], [23] . It decreased overall recurrences as compared to our conventional PV antral isolation plus CFAE ablation [24] . Interestingly, following PVI and AFN ablation,most recurrences are caused by an organized, typically fast atrial tachycardia. This residual tachycardia often appears as a transitional rhythm during AF ablation upon its organization or termination,[ Figure 1] By using spectral analysis with Fast Fourier Transform (FFT) we have found that this tachycardia is present during AF, before ablation, [25] which we have named "Background Tachycardia" (BT) [22], [26], [27] . Rapid atrial pacing following PVI and AFN ablation can also commonly induce one or more of these organized atrial tachycardias. By studying this tachycardia with spectral mapping we have found that it commonly arises from an AFN exhibiting a specific case of focal microreentry, (fractal microreentry [25] ), characterized by entry block, which ensures its maintenance during AF without overdrive reversion by the AF itself. In this study, we evaluated the long-term outcome of BT ablation as an adjunct to PVI plus substrate modification by AFN ablation in patients with LSAF. In addition, we assessed the feasibility of identifying the BT by digital processing and spectral analysis of the AF on the surface electrocardiogram (ECG) prior to the ablation procedure. Patients and methods Study PopulationIn this prospective study were enrolled 114 consecutive patients with www.jafib.com Aug-Sep 2017| Volume 10| Issue 2 AbstractBackground: Catheter ablation of long-standing persistent AF (LSAF) remains challenging. Since AF-Nest (AFN) description, we have observed that a stable, protected, fast source firing, namely "Background Tachycardia"(BT), could be hidden beneath the chaotic AF. Following pulmonary vein isolation (PVI)+AFN ablation one or more BT may arise or be induced in 30-40% of patients, which could be the culprit forAF maintenance and ablation recurrences.Methods and Results: We studied 114 patients, from 322 sequential LSAF regular ablations, having spontaneous or induced residual BT after EGM-guided PVI+AFN ablation of LSAF; 55.6±11y/o, 97males (85.1%), EF=65.5±...

Incomplete endothelialization of WatchmanTM Device: Predictors and Implications from Two Cases

“…On the other hand, the inability to ablate all responsible areas will not probably reach this result. These findings may be indicative that some unstable ATs appearing as AF, can be produced from the existence of one or more tachycardia sources [2,3] . It would be ideal if the future pursuit, insofar as simultaneous mapping is not technically feasible or absolutely reliable, to have a fast sequential mapping.…”

Estimulação vagal extracardíaca para avaliar a eficácia da denervação vagal pós-ablação dos ninhos de fibrilação atrial

“…Todos os procedimentos foram realizados nos Laboratórios de Eletrofisiologia 4 e 5 da SEMAP, localizados no centro cirúrgico do HCor, Figura 19.Os pacientes do GNFA, após serem selecionados conforme os critérios mencionados e após terem assinado o TCLE, foram submetidos à ablação de acordo com a rotina deste procedimento em nossa equipe. a) todos os pacientes eram submetidos à anestesia geral endovenosa e intubação orotraqueal, sendo o nível da anestesia controlado por dados clínicos, hemodinâmicos e por meio da avaliação da atividade cerebral pelo índice BIS potenciais fracionados no domínio do tempo, na banda de frequência entre 300 e 500 Hz1,4,29,45 . Um cateter duodecapolar era colocado no seio coronário.…”