Article

Response of Atrial Fibrillation (AF) to Pulmonary Vein Antrum Isolation (PVAI) is directly related to resumption and delay of Pulmonary Vein (PV) conduction

Klinikum Coburg, Landkreis Coburg, Bavaria, Germany
Circulation (Impact Factor: 14.95). 09/2005; 112(5):627-35. DOI: 10.1161/CIRCULATIONAHA.104.533190
Source: PubMed

ABSTRACT The role of pulmonary vein (PV) isolation in ablative treatment of atrial fibrillation (AF) has been debated in conflicting reports. We sought to compare PV conduction in patients who had no AF recurrence (group I), patients who could maintain sinus rhythm on antiarrhythmic medication (group II), and patients who had recurrent AF despite antiarrhythmic medication (group III) after PV antrum isolation (PVAI).
PV conduction was examined in consecutive patients undergoing second PVAI for AF recurrence. We also recruited some patients cured of AF to undergo a repeat, limited electrophysiological study at >3 months after PVAI. All patients underwent PVAI with an intracardiac echocardiography (ICE)-guided approach with complete isolation of all 4 PV antra (PVA). The number of PVs with recurrent conduction and the shortest atrial to PV (A-PV) conduction delay was measured with the use of consistent Lasso positions defined by ICE. Late AF recurrence was defined as AF >2 months after PVAI with the patient off medications. Patients in groups I (n=26), II (n=37), and III (n=44) did not differ at baseline (38% permanent AF; ejection fraction 53+/-6%). Recurrence of PV-left atrial (LA) conduction was seen in 1.7+/-0.8 and 2.2+/-0.8 PVAs for groups II and III but only in 0.2+/-0.4 for group I (P=0.02). In patients with recurrent PV-LA conduction, the A-PV delay increased from the first to second procedure by 69+/-47% for group III, 267+/-110% for group II, and 473+/-71% for group I (P<0.001). When pacing was at a faster rate, A-PV block developed in all 5 of the group I patients with recurrent PV-LA conduction.
The majority of patients with drug-free cure show no PV-LA conduction recurrence. Substantial A-PV delay is seen in patients able to maintain sinus rhythm on antiarrhythmic medication or cured of AF compared with patients who fail PVAI.

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    • "Durable transmurality of the ablation lines is considered the gold standard for the current treatment of atrial fibrillation (AF). One of the key aspects of AF treatment consists in ablating the pulmonary vein (PV) ostia, generally one of the thickest areas of the left atrium, obtaining their electrical disconnection [1] [2] [3]. Many technological refinements were introduced in recent years to ameliorate the efficacy of ablative energy sources, in particular bipolar radiofrequency (RF) lesions proved to be reproducibly transmural and contiguous on the cardiac muscle [4] [5]. "
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    European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 02/2015; 47(5). DOI:10.1093/ejcts/ezv016 · 2.81 Impact Factor
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    • "Some of these structural changes occur as a precursor of onset of the disease and some occur as a direct consequence of AF and further entrench the persistence of the condition—hence the expression that " Atrial fibrillation begets atrial fibrillation " [14]. One functional metric of the state of AF substrate in a patient is the detection of pre-existing low voltage tissue (or fibrosis)[15], which predicts subsequent procedural success with high fidelity. However, pre-existing voltage levels in the heart can only be determined through invasive electrophysiology study of the atrium (electroanatomical mapping). "
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    ABSTRACT: NDICE 1. Introdução 2. Ablação baseada dos Gatilhos 3. Ablação baseada no Substrato i) Eletrogramas fracionados complexos (ii) Frequência dominante (iii) Plexo Autonômico Ganglionar 4. A necessidade de Estudos Clínicos 5. Referências www.cardios.com.br Introdução A ablação por radiofreqüência da fibrilação atrial (FA) emergiu como uma técnica muito efetiva para o tratamento desta atormentadora arritmia. Quando a ablação da FA foi primeiramente descrita por Haissaguere et al, quase há dez anos, a técnica foi focada na eliminação de desencadeadores de FA, se originando grandemente das veias pulmonares (VPs) 1 . Nos pacientes com FA predominantemente paroxística e pouca doença cardíaca estrutural, este paradigma permanece de sucesso, com as evidências confirmando que a eliminação de todos os possíveis gatilhos via isolamento das veias pulmonares (IVP) previne com sucesso a recorrência da FA. Contudo, as altas taxas de sucesso dos procedimentos de IVP não foram reproduzidas em populações com FA mais persistente ou permanente. Nestes pacientes, tem havido mais interesse na identificação de elementos críticos do substrato atrial requeridos para manutenção da FA. Visando os alvos chamados "substrato", é esperado que a ablação da FA possa conseguir melhores taxas de cura num espectro maior de pacientes. Enquanto os marcadores d substrato da FA têm sido propostos como potenciais alvos para ablação, a eficácia do uso de tais alvos não é bem conhecida. Além do mais, se tais alvos devem ser eliminados sozinhos, ou em conjunto com outros gatilhos ainda não é bem entendido. Ablação Baseada nos Gatilhos O objetivo da maioria das técnicas de Ablação da FA presentes hoje em dia é "desconectar" eletricamente as VPs do resto do átrio pela ablação ao redor da origem das veias. No seu artigo original Haissaguere et al demonstraram que na maioria dos pacientes com FA paroxísticas, isoladas (94%), os gatilhos focais para FA foram encontrados em uma ou mais VPs 1 . Embora os locais fora das VPs também possam ser gatilhos da FA, isto é menos comum, ocorrendo em não mais do que 6-10% dos pacientes com FA paroxística 2 . Logo, a maioria das técnicas de hoje em dia são focadas na ablação ao redor das veias pulmonares. Isto tipicamente envolve lesões circunferenciais ao redor e fora de todas as quatro veias pulmonares com objetivo de conseguir a desconexão elétrica entre as VPs e o átrio esquerdo (AE) 3 . Embora esta técnica tenha muitos nomes e variações, incluindo "isolamento antral das veias pulmonares", "ablação circunferencial VP", ou isolamento extra ostial", os grupos de lesões produzidos pelos procedimentos são todos muito semelhantes. As taxas de sucesso também são similares, com uma análise combinada demonstrando sucesso numa média de 80% 4 . As evidências também sugerem que o sucesso de tais procedimentos de ablação é diretamente relacionado a eliminação da condução entre as VPs e o AE. Verma et al estudaram pacientes após o isolamento antral da VP e encontraram que naqueles com desfecho com sucesso tiveram significativamente mais VPs isoladas quando comparados aos que falharam 5 . Além disso, os pacientes que foram responsivos as medicações antiarrítmicas tinham mais atraso na condução entre o AE e as VPs versus os que não foram responsivos. Ouyang et al também encontraram que a recorrência da condução AE-VP foi o achado predominante nos pacientes com arritmia recorrente após o isolamento antral das VPs 6 . em ambos estudos, os pacientes foram curados com sucesso pelo re-isolamento do antro das VP. A maioria dos pacientes nestes estudos tinha FA paroxística e isolada. Estes resultados não são necessariamente aplicáveis para populações de FA mais resistentes. Além disso, o isolamento antral amplo das VP requer um grupo mais extenso de lesões, que apresentam riscos incluindo a perfuração e o AVC. Lesões adicionais e alternativas podem ser requeridas para modificar o substrato atrial da manutenção da FA, além da ablação gatilho-baseada.
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