Ablation of atrial fibrillation

Due in large part to the growing dissatisfaction with traditional pharmacologic approaches to atrial fibrillation (AF) management, and fueled by both the fruits of basic and clinical investigation into the nature of AF initiation and maintenance and the explosive development in catheter-based technologies, AF ablation has matured from a purely investigational technique to a viable--and often preferred--strategy for treating patients suffering from this arrhythmia. Future insights and developments will help us refine our treatment strategies, making AF ablation safer, faster, and more effective. As the prevalence of AF in the general population continues to expand, the goal of optimizing our approach to AF becomes ever more important--and more pressing.     

Ablation of atrial fibrillation

Atrial fibrillation (AF) is a common arrhythmia, affecting an estimated 2 million people in the United States and its prevalence increases with age, reaching 10% in those > or = 80 years. AF confers a four- to fivefold increased risk of stroke compared to the general population and has been associated with a doubling of all-cause mortality. During the past decade, limited success rates of drug treatment stimulated an exploration of interventional treatment options for AF. As our knowledge on initiating triggers and perpetuating substrate of AF expanded, different potentially curative catheter ablation techniques have been developed. In this article we review the current patient selection criteria, methods, and the results of the catheter ablation of atrial fibrillation.     

Ablation of atrial fibrillation

Fueled by dissatisfaction with pharmacologic strategies to treat atrial fbrillation (AF), the results of basic and clinical investigation into the understanding of AF initiation and maintenance mechanisms, and the explosive development in catheter-based technologies, AF ablation has matured from a purely investigational technique to a preferred, safe, and effective approach for curing AF, particularly with the circumferential approach. Future insights and developments will help us refine our treatment strategies in patients with permanent AF, making chronic AF ablation safer, faster, and more effective. As the prevalence of AF in the general population continues to increase, the purpose of optimizing our strategy becomes evermore important and more pressing.     

Ablation of atrial fibrillation

Associated with significant morbidity and mortality, atrial fibrillation is one of the most common cardiac rhythm disorders. Cure of this arrhythmia has been elusive over the years, despite development of different antiarrhythmic drugs and advances in the understanding of its pathophysiology. Initial experience with catheter ablation procedures based on the creation of linear lesions in both atria has been disappointing, but has led to the key observation that focal triggers localized in the pulmonary veins are responsible for initiation of atrial fibrillation, and thus are suitable targets for catheter ablation. With advances in technology and larger experience, it has become clear that electrical isolation of all four pulmonary veins from the left atrium provides the higher cure rates. However, the procedure is still operator dependent and is associated with a small but significant risk of pulmonary vein stenosis. Further simplification of the isolation techniques and refinement in the catheter design will allow more widespread use of this procedure and higher success rate.     

Ablation of focal atrial fibrillation

In the past decades management of atrial fibrillation (AF) has been based mainly on drug therapy. New insights into the pathophysiology of AF initiation and maintenance have provided the background for the design of catheter based procedures. The crucial role of the pulmonary veins (PVs) as triggers of AF paved the way for successful mapping and ablation. Electrical isolation of all PVs using the circular mapping approach has been shown to be an effective procedure, with reported success rates around 70 to 80% in most series. Intracardiac echocardiography is a very helpful adjunctive tool to facilitate correct positioning of the circular catheter at the PV-left atrial junction, as well as to monitor energy delivery and assist transseptal left atrial access. PV stenosis is a potential serious complication, occurring in around 2% of cases. It presents mainly with respiratory symptoms, although it is frequently asymptomatic. Spiral computed tomography is a reliable non-invasive method for imaging the PVs and can be used to screen patients for PV stenosis after radiofrequency ablation. In symptomatic patients, PV dilatation and stenting is the preferred treatment approach.The possibility of curing AF represents a major breakthrough in invasive cardiac electrophysiology. Isolation of all PVs is a very solid endpoint for successful ablation and should be pursued in all patients. It seems to be associated with high success rates over long term follow-up. Future refinements in catheter technology should provide simpler and faster procedures and render catheter ablation of AF more widespread and accepted.     

心房颤动的消融治疗

随着心房颤动机制的不断深入研究及消融技术的不断改进,消融治疗心房颤动的成功率显著提高,已成为主要治疗手段之一。但目前对各消融方法尚未形成共识,本文将较为常见的消融方法做简要介绍。     

心房颤动碎裂电位消融进展

心房颤动(房颤)消融始于20世纪90年代中叶,目前,已取得较大进展.消融术式经历了局灶消融、节段性肺静脉电隔离、环肺静脉线性消融、左房或(和)右房线性消融、神经丛消融、碎裂电位(CFAEs)消融、逐级消融等,由于对其机制认识的不同导致其消融策略多样化.CFAEs消融作为消融策略之一,最近几年进展很快,效果明显,下面对此作一综述.     

Ablation of atrial fibrillation with mitral valve surgery

PURPOSE OF REVIEW: Recent advances in understanding of the pathogenesis of atrial fibrillation and development of new technology have resulted in a surge of interest in the surgical ablation of atrial fibrillation, particularly in patients with mitral valve disease. For patients with both mitral valve dysfunction and atrial fibrillation, a variety of new approaches are available to enable a complete operation that includes both mitral valve repair and ablation of atrial fibrillation. The purposes of this review are to review the rationale for surgical ablation of atrial fibrillation (AF) in mitral valve patients, describe the classic Maze procedure and its results, detail new approaches to surgical ablation of AF, emphasize the importance of the left atrial appendage, and consider challenges and future directions in the ablation of AF in mitral valve patients. RECENT FINDINGS: Left untreated, atrial fibrillation increases mortality and morbidity in patients undergoing mitral valve surgery. While the Maze procedure effectively eliminates atrial fibrillation in most of these patients, its complexity and increased operative time has precluded widespread application. New operations that use alternative energy sources to create left atrial lesion sets ablate atrial fibrillation in 60 to 80% of patients having mitral valve surgery. SUMMARY: In mitral valve patients with atrial fibrillation of more than 6 months' duration, the operative strategy should include both mitral valve surgery and ablation of atrial fibrillation. In many cases, these procedures can be performed minimally invasively. Refinements in mapping and ablation technology are on the horizon, and these will facilitate more widespread application of minimally invasive approaches and further improve results.     

Ablation of atrial fibrillation using microwave energy--early experience

Between Dec 12, 2002 and Aug 22, 2004, 84 operative patients with chronic atrial fibrillation (AF) were subjected to AF ablation with microwave energy. Of these, 49 patients were female; their ages ranged between 20 and 72 years (mean, 43.1 years). Most patients suffered from mitral disease, accompanied in over one third of cases with tricuspid insufficiency. Thirteen patients had aortic valve disease, mostly with mitral involvement. Three patients had coronary artery disease, three had atrial septal defect and one had a left atrial (LA) myxoma. Seventy-two patients underwent endocardial ablation and 12 patients underwent epicardial ablation. Operative mortality was 4 (4.8%), and there were no major untoward postoperative events. Fifty seven patients (71.3%) had their AF converted to sinus rhythm immediately after surgery. Amiodarone or sotalol was used in all postoperative patients for 6 months, except in 8 who had bradycardia. Electrical defibrillation was utilized in cases of atrial flutter or persistent AF. Seventy patients were followed for at least 6 months. In total, 52 of them (74.3%) are still in sinus rhythm. We believe microwave ablation is a satisfactory and safe method of AF ablation, and because it is brief, it can be added to surgical procedures without undue risk to the patient.     

Ablation of persistent atrial fibrillation: Challenges and solutions

Catheter ablation is commonly used for treatment of persistent atrial fibrillation (AF). Pulmonary vein isolation (PVI) is still the cornerstone for the procedure, however, outcomes are consistently lower compared to paroxysmal AF. It is hypothesized that it could be due to lack of durable lesions or the presence of non‐PV targets that remain after PVI. Numerous advances in ablation catheter technologies and mapping systems may potentially achieve lower recurrence rates in the future. Ongoing research is required to discover the best technique for persistent AF ablation. The purpose of this review is to describe the new, developing technologies that may improve the outcome of this procedure in the persistent AF population.     

Ablation of atrial fibrillation: where are we now?]

Atrial fibrillation is the commonest arrhythmia. Besides the risk of complications, a significant number of patients remain symptomatic despite the different anti-arrhythmic drugs currently available. The only curative treatment is by surgery or catheter ablation. Since 1994, several approaches have been developed based on two main concepts: modification of the arrhythmogenic substrate by linear lesion to prevent the perpetuation of the arrhythmia and ablation of the foci initiating the atrial fibrillation. The later approach is the most popular one at the moment because the concentration of foci at the site of the pulmonary veins makes it possible to isolate them relatively easily. The presence of atrial foci in some patients complicates matters and limits the success rate to 70%. Despite these limitations and with an acceptable rate of complications, this approach appears preferable to His bundle ablation in young patients with symptomatic paroxysmal atrial fibrillation resistant to antiarrhythmic therapy.     

Ablation of atrial fibrillation using novel 4-dimensional catheter tracking within autoregistered left atrial angiograms

Background- We describe a novel fluoroscopy coregistered, 4-dimensional catheter tracking technology (MediGuide Technology [MGT]) used for treatment of patients with atrial fibrillation. The aim of the study was to investigate (1) the feasibility of nonfluoroscopic catheter manipulation within dynamic left atrial chamber models; (2) the integration of the technology into an established electroanatomical mapping system; and (3) potential clinical impact. Methods and Results- Forty-nine patients received atrial fibrillation ablation using MGT-enabled NavX-EnSite. Matched patients ablated with a conventional NavX-EnSite system served as a control group. MGT was used for the deployment of diagnostic catheters within preacquired cine loops, for nonfluoroscopic chamber mapping within dynamic angiograms, and for 4-dimensional tagging of anatomical landmarks. Integration with the electroanatomical mapping system allowed correction of field distortions and a reference tool to detect and correct map shifts. Catheter ablation was done without MGT because the ablation catheter was not MGT enabled. MGT worked safely and stably in all 49 patients. Catheter deployment within the preacquired cine loops was successfully performed in 45 of 49 (92%) patients. Catheter tracking within dynamic left atrial angiograms allowed nearly nonfluoroscopic creation of NavX-EnSite geometries with subsequent computed tomography model registration in all 49 patients. Overall, MGT significantly reduced total procedural fluoroscopy time (median [quartiles]) from 31 minutes (25, 43 minutes) to 16 minutes (10, 23 minutes) and irradiation dose from 14 453±7403 to 7363±5827 cGy*cm(2) (mean±SD), respectively (P<0.001). Conclusions- MGT is a tracking technology that allows 4-dimensional visualization of dedicated catheters within moving chamber models. Integration of the MGT with an established electroanatomical mapping system provided algorithms to facilitate mapping in the electroanatomical mapping system environment. As a first measurable clinical impact, MGT was able to reduce fluoroscopy exposure by nearly 50%.