A randomized controlled trial of the efficacy and safety of electroanatomic circumferential pulmonary vein ablation supplemented by ablation of complex fractionated atrial electrograms versus potential-guided pulmonary vein antrum isolation guided by intracardiac ultrasound

Catheter Ablation for the Management of Atrial Fibrillation: An Update of the Literature

Catheter ablation has been shown to be more effective at maintaining sinus rhythm and improving quality of life when compared to antiarrhythmic drugs. Radiofrequency and cryoablation are two effective methods. However, catheter-only ablation strategies have not consistently produced high success rates in treating longstanding and persistent AF patients. The emerging treatment of choice for such cases is hybrid ablation, which involves a multidisciplinary and minimally invasive approach to achieve surgical ablation of the direct posterior left atrial wall in combination with endocardial catheter ablation. Studies have shown promising results for the hybrid approach when compared with catheter ablation alone, but it is not without risks. Large and randomised studies are necessary to further evaluate these strategies for managing AF.

Comparing efficacy and safety in catheter ablation strategies for atrial fibrillation: a network meta-analysis

BACKGROUND

There is no consensus on the most efficient catheter ablation (CA) strategy for patients with atrial fibrillation (AF). The objective of this study was to compare the efficacy and safety of different CA strategies for AF ablation through network meta-analysis (NMA).

METHODS

A systematic search of PubMed, Web of Science, and CENTRAL was performed up to October 5th, 2020. Randomized controlled trials (RCT) comparing different CA approaches were included. Efficacy was defined as arrhythmia recurrence after CA and safety as any reported complication related to the procedure during a minimum follow-up time of 6 months.

RESULTS

In total, 67 RCTs (n = 9871) comparing 19 different CA strategies were included. The risk of recurrence was significantly decreased compared to pulmonary vein isolation (PVI) alone for PVI with renal denervation (RR: 0.60, CI: 0.38-0.94), PVI with ganglia-plexi ablation (RR: 0.62, CI: 0.41-0.94), PVI with additional ablation lines (RR: 0.8, CI: 0.68-0.95) and PVI in combination with bi-atrial modification (RR: 0.32, CI: 0.11-0.88). Strategies including PVI appeared superior to non-PVI strategies such as electrogram-based approaches. No significant differences in safety were observed.

CONCLUSIONS

This NMA showed that PVI in combination with additional CA strategies, such as autonomic modulation and additional lines, seem to increase the efficacy of PVI alone. These strategies can be considered in treating patients with AF, since, additionally, no differences in safety were observed. This study provides decision-makers with comprehensive and comparative evidence about the efficacy and safety of different CA strategies.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registry number: CRD42020169494 .

Radiofrequency ablation for treatment of atrial fibrillation with the use of intracardiac echocardiography vs without intracardiac echocardiography: A meta-analysis of observational and randomized studies

AIMS

Intracardiac echocardiography (ICE) provides superior quality images and can monitor catheter location within the heart continuously. Given the limited evidence, we conducted the meta-analysis to evaluate outcomes with ICE in radiofrequency (RF) ablation of atrial fibrillation (AF).

METHODS AND RESULTS

PubMed/MEDLINE, Embase and Cochrane were searched for studies reporting RF ablation for treatment of AF with the use of ICE vs without ICE and 12 studies were included. Sensitivity analyses limiting studies to ablation with the use of contact force (CF) catheters were conducted and subgroup analyses were performed according to the published year. In main analyses, RF ablation with ICE for treatment of AF was associated with significant reduction in total X-ray time (MD, -9.80; 95% CI, -15.57 to -4.04; I² =99%; p <0.01), total procedure time (MD, -17.65; 95% CI, -30.22 to -5.09; I² =89%; p <0.01), and complications (RR, 0.90; 95% CI, 0.87 to 0.92; I² =20%; p<0.01) vs without ICE. The ICE-guided group tended to decrease total absorbed X-ray dose (SMD, -0.91; 95% CI, -1.86 to 0.04; I² =96%; p =0.06). Freedom from arrhythmia (RR, 1.06; 95% CI, 0.98 to 1.14; I² =0%; p =0.13) was comparable between the two groups.

CONCLUSION

In patients with AF, ICE-guided RF ablation is correlated with significant reductions in total X-ray time, total procedure time, and complications vs ablation without ICE. Total absorbed X-ray dose tends to reduce in the ICE group and freedom from arrhythmia is comparable between the two groups. This article is protected by copyright. All rights reserved.

The use of intracardiac echocardiography catheters in endocardial ablation of cardiac arrhythmia: Meta-analysis of efficiency, effectiveness, and safety outcomes

Aims

The optimal use of intracardiac echocardiography (ICE) may reduce fluoroscopy time and procedural complications during endocardial ablation of cardiac arrhythmias. Due to limited evidence in this area, we conducted the first systematic literature review and meta‐analysis to evaluate outcomes associated with the use of ICE.

Methods and Results

Studies reporting the use of ICE during ablation procedures vs without ICE were searched using PubMed/MEDLINE. A meta‐analysis was performed on the 19 studies (2186 patients) meeting inclusion criteria, collectively representing a broad range of arrhythmia mechanisms. Use of ICE was associated with significant reductions in fluoroscopy time (Hedges' g −1.06; 95% confidence interval [CI] −1.81 to −0.32; P < .01), fluoroscopy dose (Hedges' g −1.27; 95% CI −1.91 to −0.62; P < .01), and procedure time (Hedges' g −0.35; 95% CI −0.64 to −0.05; P = .02) vs ablation without ICE. A 6.95 minute reduction in fluoroscopy time and a 15.2 minute reduction in procedure time was observed between the ICE vs non‐ICE groups. These efficiency gains were not associated with any decreased effectiveness or safety. Sensitivity analyses limiting studies to an atrial fibrillation (AF) only population yielded similar results to the main analysis.

Conclusion

The use of ICE in the ablation of cardiac arrhythmias is associated with significantly lower fluoroscopy time, fluoroscopy dose, and shorter procedure time vs ablation without ICE. These efficiency improvements did not compromise the clinical effectiveness or safety of the procedure.

The Use of Innovative Technologies to Guide Cardiac Procedures

The advantages of intracardiac echocardiography (ICE) include shorter procedure times, reduced radiation exposure and the elimination of the need for general anesthesia. It is also effective in the safe performance of transseptal punctures. These have led to its increasing use in electrophysiology (EP) procedures. The use of ICE provides unrestricted access to the cardiac anatomy and guides interventional cardiac procedures by providing high-quality images of intracardiac structures and devices. As well as their use as imaging in catheter ablation of atrial fibrillation and other arrhythmias, ICE ultrasound catheters may be used in cardiac valve repair and the closure of atrial septal defects (ASDs). Integration of ICE catheters with electroanatomical mapping systems that construct three dimensional (3D) images have further increased the application of the technique. The use of magnetic navigation systems (MNS) have conferred further advantages including reduced exposure to fluoroscopy and increased operator comfort. This article presents four clinical cases and reviews clinical studies of these techniques.

Atrial fibrillation: review of current treatment strategies

Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia in modern clinical practice, with an estimated prevalence of 1.5-2%. The prevalence of AF is expected to double in the next decades, progressing with age and increasingly becoming a global medical challenge. The first-line treatment for AF is often medical treatment with either rate control or anti-arrhythmic agents for rhythm control, in addition to anti-coagulants such as warfarin for stroke prevention in patient at risk. Catheter ablation has emerged as an alternative for AF treatment, which involves myocardial tissue lesions to disrupt the underlying triggers and substrates for AF. Surgical approaches have also been developed for treatment of AF, particularly for patients requiring concomitant cardiac surgery or those refractory to medical and catheter ablation treatments. Since the introduction of the Cox-Maze III, this procedure has evolved into several modern variations, including the use of alternative energy sources (Cox-Maze IV) such as radiofrequency, cryo-energy and microwave, as well as minimally invasive thoracoscopic epicardial approaches. Another recently introduced technique is the hybrid ablation approach, where in a single setting both epicardial thoracoscopic ablation lesions and endocardial catheter ablation lesions are performed by the cardiothoracic surgeon and cardiologist. There remains controversy surrounding the optimal approach for AF ablation, energy sources, and lesion sets employed. The goal of this article is review the history, classifications, pathophysiology and current treatment options for AF.

Pulmonary Vein Antrum Isolation in Patients With Paroxysmal Atrial Fibrillation: More Than a Decade of Follow-Up

BACKGROUND

We report the outcome of pulmonary vein (PV) antrum isolation in paroxysmal atrial fibrillation (AF) patients over more than a decade of follow-up.

METHODS AND RESULTS

A total of 513 paroxysmal AF patients (age 54±11 years, 73% males) undergoing catheter ablation at our institutions were included in this analysis. PV antrum isolation extended to the posterior wall between PVs plus empirical isolation of the superior vena cava was performed in all. Non-PV triggers were targeted during repeat procedure(s). Follow-up was performed quarterly for the first year and every 6 to 9 months thereafter. The outcome of this study was freedom from recurrent AF/atrial tachycardia. At 12 years, single-procedure arrhythmia-free survival was achieved in 58.7% of patients. Overall, the rate of recurrent arrhythmia (AF/atrial tachycardia) was 21% at 1 year, 11% between 1 and 3 years, 4% between 3 and 6 years, and 5.3% between 6 and 12 years. Repeat procedure was performed in 74% of patients. Reconnection in the PV antrum was found in 31% of patients after a single procedure and in no patients after 2 procedures. Non-PV triggers were found and targeted in all patients presenting with recurrent arrhythmia after ≥2 procedures. At 12 years, after multiple procedures, freedom from recurrent AF/atrial tachycardia was achieved in 87%.

CONCLUSIONS

In patients with paroxysmal AF undergoing extended PV antrum isolation, the rate of late recurrence is lower than what previously reported with segmental or less extensive antral isolation. However, over more than a decade of follow-up, nearly 14% of patients developed recurrence because of new non-PV triggers.

Catheter Ablation of Paroxysmal Atrial Fibrillation: Have We Achieved Cure with Pulmonary Vein Isolation?

Pulmonary vein isolation (PVI) is the cornerstone of current ablation techniques to eliminate atrial fibrillation (AF), with the greatest efficacy as a stand-alone procedure in patients with paroxysmal AF. Over the years, techniques for PVI have undergone a profound evolution, and current guidelines recommend PVI with confirmation of electrical isolation. Despite significant efforts, PV reconnection is still the rule in patients experiencing post-ablation arrhythmia recurrence. In recent years, use of general anesthesia with or without jet ventilation, open-irrigated ablation catheters, and steerable sheaths have been demonstrated to increase the safety and efficacy of PVI, reducing the rate of PV reconnection over follow-up. The widespread clinical availability of ablation catheters with real-time contact force information will likely further improve the effectiveness and safety of PVI. In a small but definite subset of patients, post-ablation recurrent arrhythmia is due to non-PV triggers, which should be eliminated in order to improve success. Typically, non-PV triggers cluster in specific regions such as the coronary sinus, the inferior mitral annulus, the interatrial septum, the left atrial appendage, the Eustachian ridge, the crista terminalis region, the superior vena cava, and the ligament of Marshall. Focal ablation targeting the origin of the trigger is recommended in most cases. Empirical non-PV ablation targeting the putative substrate responsible for AF maintenance with ablation lines and/or elimination of complex fractionated electrograms has not been shown to improve success compared to PVI alone. Similarly, the role of novel substrate-based ablation approaches targeting putative localized sources of AF (e.g., rotors) identified by computational mapping techniques is unclear, as they have never been compared to PVI and non-PV trigger ablation in an adequately designed randomized trial. This review highlights PVI techniques and outcomes in treating recurrent drug-refractory AF and discusses the potential role of additional non-PV ablation.

Ablation as First-Line Therapy for Atrial Fibrillation: Yes

This article addresses the use of catheter ablation (CA) as first-line therapy for atrial fibrillation (AF). CA increases long-term freedom from AF, reduces hospitalizations, and improves quality of life compared with antiarrhythmic drug (AAD) therapy in patients with symptomatic AF who have already failed one AAD. The role of CA as first-line therapy for AF, however, is still controversial. Evidence from randomized controlled trials shows that CA is definitely superior to AADs as first-line therapy for relatively young patients with paroxysmal AF, with comparable complication rates and results consistently reproducible across different institutions, operators, and types of ablation approaches.

Direct left atrial ICE imaging guided ablation for atrial fibrillation without employing contrast medium

BACKGROUND

Preoperative and intraoperative use of a contrast medium is unavoidable in catheter ablation for atrial fibrillation, which can become a particularly significant issue for patients suffering from renal impairment.

OBJECTIVE

The purpose of this study is to investigate the feasibility and safety of a technique for atrial fibrillation ablation without a contrast medium via intra-cardiac ultrasound imaging only.

METHODS

We prepared the geometry of the pulmonary vein and left atrium via a SOUNDSTAR catheter from inside the left atrium, without preoperative and intraoperative investigations using contrast mediums, for computed tomography or magnetic resonance imaging and pulmonary venography. This was followed by retrospective investigation of the success rate and complications observed in 200 successive paroxysmal and persistent atrial fibrillation cases that underwent catheter ablation from January 2011 to November 2012. The outcomes were assessed after the one-year follow-up.

RESULTS

Inserting a SOUNDSTAR catheter into the left atrium was successful in all cases, wherein rendering of all pulmonary veins and the left atrium was possible, and extensive encircling pulmonary vein isolation was successful in all cases. The sinus rhythm maintenance rate one year after the procedure was 90.4% for paroxysmal atrial fibrillation and 76.0% for persistent atrial fibrillation. The major complication rate was 0.5% (cardiac tamponade), with no cases presenting aggravation of renal function.

CONCLUSION

Atrial fibrillation ablation using an intra-cardiac ultrasound from the left atrium without employing a contrast medium was safe, with no adverse effects on renal function.

New Imaging Technologies To Characterize Arrhythmic Substrate

The cornerstone of the new imaging technologies to treat complex arrhythmias is the electroanatomic (EAM) mapping. It is based on tissue characterization and in particular on determination of low potential region and dense scar definition. Recently, the identification of fractionated isolated late potentials increased the specificity of the information derived from EAM. In addition, non-invasive tools and their integration with EAM, such as cardiac magnetic resonance imaging and computed tomography scanning, have been shown to be helpful to characterize the arrhythmic substrate and to guide the mapping and the ablation. Finally, intracardiac echocardiography, known to be useful for several practical uses in the setting of electrophysiological procedures, it has been also demonstrated to provide important informations about the anatomical substrate and may have potential to identify areas of scarred myocardium.

Impact of biatrial defragmentation in patients with paroxysmal atrial fibrillation: results from a randomized prospective study

BACKGROUND

Single procedure success rates of pulmonary vein isolation (PVI) in patients with paroxysmal atrial fibrillation (PAF) are still unsatisfactory. In patients with persistent atrial fibrillation (AF), ablation of complex fractionated atrial electrograms (CFAEs) after PVI results in improved outcomes.

OBJECTIVE

We aimed to investigate if PAF-patients with intraprocedurally sustained AF after PVI might benefit from additional CFAE ablation.

METHODS

A total of 1134 consecutive patients underwent a first catheter ablation procedure of PAF between June 2008 and December 2012. In most patients, AF was either not inducible or terminated during PVI. In 68 patients (6%), AF sustained after successful PVI. These patients were randomized to either cardioversion (PVI-alone group; n = 33) or additional CFAE ablation (PVI+CFAE group; n = 35) and followed up every 1-3 months and serial Holter recordings were also obtained. The primary end point was the recurrence of AF/atrial tachycardia (AT) after a blanking period of 3 months.

RESULTS

Procedure duration (127 ± 6 minutes vs 174 ± 10 minutes), radiofrequency application time (44 ± 3 minutes vs 74 ± 5 minutes), and fluoroscopy time (26 ± 2 minutes vs 41 ± 3 minutes) were longer in the PVI+CFAE group (all P < .001). In 30 of 35 patients (86%) in the PVI+CFAE group, ablation terminated AF. There was no significant group difference with respect to freedom from AF/AT (22 of 33 [67%] vs 22 of 35 [63%]; P = .66). Subsequently, 10 of 11 patients in the PVI-alone group (91%) and 11 of 13 patients in PVI+CFAE group (85%) underwent repeat ablation (P = 1.00). Overall, 29 of 33 [88%] vs 30 of 35 [86%] patients (P = 1.00) were free from AF/AT after 1.4 ± 0.1 vs 1.4 ± 0.2 (P = .87) procedures.

CONCLUSION

Patients with sustained AF after PVI in a PAF cohort are rare. Regarding AF/AT recurrence, these patients did not benefit from further CFAE ablation compared to PVI alone, but are exposed to longer procedure duration, fluoroscopy time, and radiofrequency application time.

Organizational index mapping to identify focal sources during persistent atrial fibrillation

INTRODUCTION

Localized rotors have been implicated in the mechanism of persistent atrial fibrillation (AF). Although regions of highest dominant frequency (DF) on spectral analysis of the left atrium (LA) have been said to identify rotors, other mechanisms such as wavefront collisions will sporadically also generate an inconsistent distribution of high DF. We hypothesized that if drivers of AF were present, their distinctive spectral characteristics would result more from their temporal stability than their high frequency.

METHODS AND RESULTS

Ten patients with persistent AF underwent LA noncontact mapping. Following subtraction of far-field ventricular components, noncontact electrograms at 256 sites underwent fast Fourier transform. Mean absolute difference in DF between 5 sequential 7-second segments of AF was defined as the DF variability (DFV) at each site. Mean ratio of the DF and its harmonics to the total power of the spectrum was defined as the organizational index (OI). Mean DFV was significantly lower in organized areas (OI > 1 SD above mean) than at all sites (0.34 ± 0.04 vs 0.46 ± 0.04 Hz; P < 0.001). When organized areas were ablated during wide-area circumferential ablation, AF organized in remote regions (LA appendage ΔOI ablated vs unablated: +0.21 [0.06-0.41] vs -0.04 [-0.14-0.05]; P = 0.005).

CONCLUSIONS

At sites of organized activation, the activation frequency was also significantly more stable over time. This observation is consistent with the existence of focal sources, and inconsistent with a purely random activation pattern. Ablation of such regions is technically feasible, and was associated with organization of AF in remote atrial regions.

Visual, tactile, and contact force feedback: which one is more important for catheter ablation? Results from an in vitro experimental study

BACKGROUND

During radiofrequency ablation, effective contact is crucial in determining lesions efficacy.

OBJECTIVE

The purpose of this study was to compare operators' ability to assess contact pressure using visual and tactile feedbacks together or alone in an experimental model.

METHODS

In a in vitro experimental setup replicating manual catheter manipulation and recording the applied force, evaluators were asked to identify three levels of force (first, ablation, and maximum contact) as the catheter contacted the tissue model using (1) visual feedback only by fluoroscopy, "blinded" to touch; (2) tactile feedback only, blinded to fluoroscopy; and (3) both tactile and visual feedback together. The latter was regarded as reference. The experiment was repeated using a catheter force sensing technology during robotic navigation.

RESULTS

During manual navigation, tighter association was shown for the visual method than for the tactile method: median difference with reference: first contact -1 (P = .97) vs -2 (P = .90); ablation contact 2 (P = .1) vs -7 (P = .03); maximum contact 2 (P = .06) vs -28 (P = .02). Bland-Altman plot and Deming regression confirmed for the visual method the good agreement with reference and the absence of bias at any level and showed for the tactile higher values and proportional bias that reached statistical significance at ablation and maximum contact. During robotic navigation, agreement was higher for the tactile than for the visual only method.

CONCLUSION

During manual navigation, visual feedback alone is in better agreement with the reference compared to the tactile only approach. During robotic navigation, agreement is looser for the visual only approach. More objective feedback of contact pressure during ablation procedures is desirable.

Current hot potatoes in atrial fibrillation ablation

Atrial fibrillation (AF) ablation has evolved to the treatment of choice for patients with drug-resistant and symptomatic AF. Pulmonary vein isolation at the ostial or antral level usually is sufficient for treatment of true paroxysmal AF. For persistent AF ablation, drivers and perpetuators outside of the pulmonary veins are responsible for AF maintenance and have to be targeted to achieve satisfying arrhythmia-free success rate. Both complex fractionated atrial electrogram (CFAE) ablation and linear ablation are added to pulmonary vein isolation for persistent AF ablation. Nevertheless, ablation failure and necessity of repeat ablations are still frequent, especially after persistent AF ablation. Pulmonary vein reconduction is the main reason for arrhythmia recurrence after paroxysmal and to a lesser extent after persistent AF ablation. Failure of persistent AF ablation mostly is a consequence of inadequate trigger ablation, substrate modification or incompletely ablated or reconducting linear lesions. In this review we will discuss these points responsible for AF recurrence after ablation and review current possibilities on how to overcome these limitations.

Role of Intracardiac echocardiography in Atrial Fibrillation Ablation

In the recent years, several new evidences support catheter-based ablation as a treatment modality of atrial fibrillation (AF). Based on a plenty of different applications, intracardiac echocardiography (ICE) is now a well-established technology in complex electrophysiological procedures, in particular in AF ablation. ICE contributes to improve the efficacy and safety of such procedures defining the anatomical structures involved in ablation procedures and monitoring in real time possible complications. In particular ICE allows: a correct identification of the endocardial structures; a guidance of transseptal puncture; an assessment of accurate placement of the circular mapping catheter; an indirect evaluation of evolving lesions during radiofrequency (RF) energy delivery via visualization of micro and macrobubbles tissue heating; assessment of catheter contact with cardiac tissues. Recently, also the feasibility of the integration of electroanatomical mapping (EAM) and intracardiac echocardiography has been demonstrated, combining accurate real time anatomical information with electroanatomical data. As a matter of fact, different techniques and ablation strategies have been developed throughout the years. In the setting of balloon-based ablation systems, recently adopted by an increasing number of centers, ICE might have a role in the choice of appropriate balloon size and to confirm accurate occlusion of pulmonary veins. Furthermore, in the era of minimally fluoroscopic ablation, ICE has successfully provided a contribute in reducing fluoroscopy time. The purpose of this review is to summarize the current applications of ICE in catheter based ablation strategies of atrial fibrillation, focusing-on electronically phased-array ICE.

Electrogram fractionation: the relationship between spatiotemporal variation of tissue excitation and electrode spatial resolution

BACKGROUND

Fractionated electrograms are used by some as targets for ablation in atrial and ventricular arrhythmias. Fractionation has been demonstrated to result when there is repetitive or asynchronous activation of separate groups of cells within the recording region of a mapping electrode(s).

METHODS AND RESULTS

Using a computer model, we generated tissue activation patterns with increasing spatiotemporal variation and calculated virtual electrograms from electrodes with decreasing resolution. We then quantified electrogram fractionation. In addition, we recorded unipolar electrograms during atrial fibrillation in 20 patients undergoing atrial fibrillation ablation. From these we constructed bipolar electrograms with increasing interelectrode spacing and quantified fractionation. During modeling of spatiotemporal variation, fractionation varied directly with electrode length, diameter, height, and interelectrode spacing. When resolution was held constant, fractionation increased with increasing spatiotemporal variation. In the absence of spatial variation, fractionation was independent of resolution and proportional to excitation frequency. In patients with atrial fibrillation, fractionation increased as interelectrode spacing increased.

CONCLUSIONS

We created a model for distinguishing the roles of spatial and temporal electric variation and electrode resolution in producing electrogram fractionation. Spatial resolution affects fractionation attributable to spatiotemporal variation but not temporal variation alone. Electrogram fractionation was directly proportional to spatiotemporal variation and inversely proportional to spatial resolution. Spatial resolution limits the ability to distinguish high-frequency excitation from overcounting. In patients with atrial fibrillation, complex fractionated atrial electrogram detection varies with spatial resolution. Electrode resolution must therefore be considered when interpreting and comparing studies of fractionation.

Organized atrial tachycardias after atrial fibrillation ablation

The efficacy of catheter-based ablation techniques to treat atrial fibrillation is limited not only by recurrences of this arrhythmia but also, and not less importantly, by new-onset organized atrial tachycardias. The incidence of such tachycardias depends on the type and duration of the baseline atrial fibrillation and specially on the ablation technique which was used during the index procedure. It has been repeatedly reported that the more extensive the left atrial surface ablated, the higher the incidence of organized atrial tachycardias. The exact origin of the pathologic substrate of these trachycardias is not fully understood and may result from the interaction between preexistent regions with abnormal electrical properties and the new ones resultant from radiofrequency delivery. From a clinical point of view these atrial tachycardias tend to remit after a variable time but in some cases are responsible for significant symptoms. A precise knowledge of the most frequent types of these arrhythmias, of their mechanisms and components is necessary for a thorough electrophysiologic characterization if a new ablation procedure is required.

CARTO-guided vs. NavX-guided pulmonary vein antrum isolation and pulmonary vein antrum isolation performed without 3-D mapping: effect of the 3-D mapping system on procedure duration and fluoroscopy time

PURPOSE

Pulmonary vein antrum isolation (PVAI) guided by intracardiac echocardiography and a roaming circular mapping catheter is an effective treatment modality for atrial fibrillation. Unfortunately, the complexity of this technique leads to long procedure times and high fluoroscopy exposure. This study examined the effect of two different mapping systems on the procedural characteristics and clinical outcomes of PVAI for atrial fibrillation.

METHODS

Referred patients underwent PVAI using a magnetic-based 3-dimensional (3-D) mapping (CARTO® System; group 1), a current-based system (EnSite NavX™; group 2), or fluoroscopy without 3-D mapping (group 3) between February 2004 and November 2009.

RESULTS

Data were analyzed from 71 patients in group 1, 165 patients in group 2, and 197 patients in group 3. Baseline characteristics and measured long-term outcomes did not differ between the groups. Although patients in group 1 were more likely to undergo a concurrent flutter ablation (P = 0.01), they had significantly shorter procedure time, fluoroscopy time, and radiofrequency energy delivery time compared with group 2 and 3 patients. No difference was detected among the groups with respect to recurrence, mean time to recurrence, or number of PVAI procedures.

CONCLUSIONS

Use of a magnetic-based 3-D mapping system, which allows precise spatial localization of the ablation catheter, was associated with significantly lower procedure time, fluoroscopy duration, and radiofrequency energy delivery time during catheter ablation for atrial fibrillation compared with a current-based system and ablation performed without 3-D mapping, although measured short- and long-term clinical outcomes were similar.

Efficacy of adjunctive ablation of complex fractionated atrial electrograms and pulmonary vein isolation for the treatment of atrial fibrillation: a meta-analysis of randomized controlled trials

AIMS

Although useful, percutaneous left atrial ablation for pulmonary vein isolation (PVI) does not eliminate atrial fibrillation (AF) in all patients. The ablation of complex fractionated atrial electrograms (CFAEs) has been proposed as an adjunctive strategy to improve the maintenance of sinus rhythm after PVI. Our objective was to analyse the efficacy of adjunctive CFAE ablation.

METHODS AND RESULTS

We meta-analysed six randomized controlled trials (total, n=538) using random-effects modelling to compare PVI (n=291) with PVI plus CFAE ablation (PVI+CFAE) (n=237). The primary outcome was freedom from AF or other atrial tachyarrhythmias (ATs) after a single ablation with or without antiarrhythmic drugs. Following a single ablation, PVI+CFAE improved the odds of freedom from any AF/AT compared with PVI alone (odds ratio 2.0, 95% confidence interval 1.04-3.8, P=0.04) at ≥3-month follow-up. There was moderate heterogeneity among trials (I2=63.0%). Complex fractionated atrial electrogram ablation significantly increased mean procedural (178.5±66.9 vs. 331.5±92.6 min, P<0.001), mean fluoroscopy (59.5±22.2 vs. 115.5±35.3 min, P<0.001), and mean radiofrequency (RF) energy application times (46.9±36.6 vs. 74.4±43.0 min, P<0.001).

CONCLUSIONS

Pulmonary vein isolation followed by adjunctive CFAE ablation is associated with increased freedom from AF after a single procedure. Adjunctive CFAE ablation increased procedural, fluoroscopy, and RF application times, and the risk/benefit profile of adjunctive CFAE ablation deserves further evaluation with additional studies and longer-term follow-up.

Elusive atrial substrate: complex fractionated atrial electrograms and beyond

Most practitioners of atrial fibrillation (AF) ablation have attempted to move beyond pulmonary vein isolation into the realm of physiology-driven ablation for patients with persistent AF. This new strategy involves a combination of a common anatomic approach (with isolation of the pulmonary veins) and an individualized strategy tailored to the electrophysiologic characteristics of the atrial substrate present in each patient. In this review, we summarize the current reasoning and controversies related to this new approach. In addition, we attempt to unravel some of the complexities of targeting these patient-specific atrial electrical signals.