Vein Isolation For Persistent Atrial Fibrillation Research Articles

Novel approaches to mechanism-based atrial fibrillation ablation.

Modern cardiac electrophysiology has reported significant advances in the understanding of mechanisms underlying complex wave propagation patterns during atrial fibrillation (AF), although disagreements remain. One school of thought adheres to the long-held postulate that AF is the result of randomly propagating wavelets that wonder throughout the atria. Another school supports the notion that AF is deterministic in that it depends on a small number of high-frequency rotors generating three-dimensional scroll waves that propagate throughout the atria. The spiralling waves are thought to interact with anatomic and functional obstacles, leading to fragmentation and new wavelet formation associated with the irregular activation patterns documented on AF tracings. The deterministic hypothesis is consistent with demonstrable hierarchical gradients of activation frequency and AF termination on ablation at specific (non-random) atrial regions. During the last decade, data from realistic animal models and pilot clinical series have triggered a new era of novel methodologies to identify and ablate AF drivers outside the pulmonary veins. New generation electroanatomical mapping systems and multielectrode mapping catheters, complimented by powerful mathematical analyses, have generated the necessary platforms and tools for moving these approaches into clinical procedures. Recent clinical data using such platforms have provided encouraging evidence supporting the feasibility of targeting and effectively ablating driver regions in addition to pulmonary vein isolation in persistent AF. Here, we review state-of-the-art technologies and provide a comprehensive historical perspective, characterization, classification, and expected outcomes of current mechanism-based methods for AF ablation. We discuss also the challenges and expected future directions that scientists and clinicians will face in their efforts to understand AF dynamics and successfully implement any novel method into regular clinical practice.

Combined pulmonary vein stenosis stenting and left atrial appendage occlusion in a patient with hemoptysis after atrial fibrillation ablation

BackgroundPulmonary vein stenosis (PVS) after radiofrequency ablation for non-valvular atrial fibrillation (AF) is an uncommon but serious complication. PVS stenting can rapidly restore pulmonary flow and improve symptoms with long-term low incidence of restenosis. However, high risk of thrombosis remains if AF is recurrent, especially for CHA2DS2-VASc > 2.Case presentationA 67-year-old man with diabetes, hypertension and a history of stroke underwent radiofrequency pulmonary vein isolation for persistent AF 1 year ago. Six months later he developed recurrent respiratory infection and massive hemoptysis. Computed tomography pulmonary angiography revealed severe left pulmonary vein stenosis. Simultaneous percutaneous PVS stenting and left atrial appendage occlusion were performed to resolve recurrent hemoptysis and prevent stroke. The clinical follow-up indicated a good short and mid-term result with significant improvement of symptoms.ConclusionsSimultaneous PVS stenting and left atrial appendage occlusion is feasible and effective in patients with recurrence of AF and hemoptysis induced by radiofrequency ablation for AF.

Left Atrial Appendage Electrical Isolation as a Target in Atrial Fibrillation.

Although the benefit of catheter ablation of the pulmonary veins is well established in paroxysmal atrial fibrillation (AF), the optimal ablation strategy for persistent AF is yet to be determined. Pulmonary vein isolation in persistent AF often results in AF recurrence and the success rate may be low even after multiple procedures. Recurrent AF risk may besecondary to non-pulmonary vein triggers, and adjunctive therapies to better control persistent AF are under investigation. The left atrial appendage (LAA) is a complex structure with distinct physiological and electrical properties, and multiple studies have implicated the LAA as a potential contributor to persistence of AF. Therapies targeting the LAA for electrical isolation have demonstrated potential efficacy in freedom from AF. The overarching concept of this therapy is to isolate the atria electrically from the LAA via catheter ablation, surgical excision or ligation, or percutaneous ligation. LAA electrical isolation has already demonstrated benefit in reducing AF recurrence and AF burden. LAA electrical isolation has the potential to form a foundational piece in the optimal rhythm control management of AF and thereforewarrants further study and is the focus of this review.

Catheter Ablation for Persistent Atrial Fibrillation

A new era of atrial fibrillation (AF) treatment began in 1997–1998 with the discovery that triggers within the pulmonary veins initiate AF and reports that elimination of these triggers is successful in treating AF in its paroxysmal form.1–3 However, in patients with persistent AF, the success rate of exclusive pulmonary vein isolation is substantially lower.4,5 To improve the outcome of persistent AF ablation, different ablation strategies have been explored, but to date the optimal strategy has not been defined. Although some groups argue that limited ablation, including pulmonary vein isolation and, if present, ablation of nonpulmonary vein triggers, is sufficient for persistent AF ablation, other groups, including ours, favor more extensive, substrate-based ablation in addition to pulmonary vein isolation. In this review, we will discuss the rationale for a substrate-based ablation strategy to treat persistent AF and show why elimination of triggers is not sufficient in most patients with persistent AF. Response by Roten et al on p 1232 In a simple model, an electric impulse in AF can form because of abnormalities in impulse generation (triggers) or can result from abnormal impulse propagation (reentry). By a strict definition, a trigger is a focal source of new impulse generation. The mechanism by which a new impulse can form is either abnormal automaticity or triggered activity. Trigger-ablation protocols target these sources of new impulse generation. Abnormal impulse propagation, on the other hand, depends on altered substrate properties causing nonuniform or slowed conduction. This in turn causes multiple forms of wave reentry thought to be responsible for AF perpetuation: random reentry (multiple wavelets), macro- and microreentry, or functional reentry (rotors). Substrate-based ablation strategies aim to abate abnormal impulse propagation and interrupt any form of atrial reentry. Triggers of paroxysmal AF are mainly located in the pulmonary …