Complex Fractionated Atrial Electrogram or Linear Ablation in Patients with Persistent Atrial Fibrillation-A Prospective Randomized Study

Which ablation strategy is the most effective for treating persistent atrial fibrillation? A systematic review and bayesian network meta-analysis of randomized controlled trials

There is no consensus on the most efficient ablation strategy for patients with persistent atrial fibrillation (PerAF). This study aimed to conduct a systematic review and network meta-analysis (NMA) to evaluate the effectiveness of different ablation strategies for PerAF. The primary efficacy outcome was the recurrence of any atrial arrhythmia after a single ablation procedure during the follow-up period. The primary safety outcome of interest was any reported complication related to the procedure. The secondary outcome was the procedure time. Fifty-two studies with 9048 patients were included in this NMA. The studies were conducted between 2004 and 2024, and 22 different ablation strategies were identified. Pulmonary vein isolation + posterior wall box isolation + extra-pulmonary vein isolation was the most effective ablation therapy for PerAF. Most additional substrate modification ablation strategies do not show significant additional benefits. There were no significant differences in the incidence of procedure-related complications between the different ablation strategies. Pulmonary vein isolation combined with additional ablation sites increases the duration of the procedure.

Real-world evidence demonstrates an appropriate atrial fibrillation population for hybrid convergent approach versus stand-alone cryoballoon ablation: A long-term safety and efficacy study

INTRODUCTION

A hybrid convergent approach (endocardial and epicardial ablation) demonstrated superior effectiveness in a recent randomized study for long-standing persistent atrial fibrillation (LSPAF). Yet, there is a lack of real-world, long-term evidence as to which patients are best candidates for a hybrid convergent approach compared to standard endocardial cryoballoon pulmonary vein isolation (CB PVI).

METHODS AND RESULTS

This single-center, retrospective analysis spanning from 2010 to 2015 compared two distinctly different atrial fibrillation (AF) cohorts; one treated with stand-alone cryoablation and one treated with a hybrid convergent approach. Baseline characteristics described candidates for each approach. The following criteria were utilized to determine CB PVI candidacy: (1) paroxysmal AF (PAF) (stage 3A) with failed class I/III antiarrhythmic drug (AAD) or (2) persistent/LSPAF (stage 3B/3C/3D) with failed class I/III AAD unwilling to undergo hybrid procedure. Selection criteria for the hybrid procedure included: (1) PAF refractory to both class I/III AAD and prior CB PVI (stage 3D) or (2) persistent/LSPAF (stage 3B/3C/3D) with failed class I/III AAD agreeable to hybrid procedure. Prior sternotomy was excluded. Serial electrocardiograms and continuous monitoring evaluated primary efficacy outcome of time-to-first recurrence of atrial arrhythmia after a 90-day blanking period. Secondary outcomes were procedure-related complications and AAD use (at discharge, 12, and 36 months). Kaplan-Meier methods evaluated arrhythmia recurrence. Of 276 patients, 197 (64.2 ± 10.6 years old; 66.5% male; 74.1% 3A-PAF; 18.3% 3B/3D-persistent AF; 1.0% 3C-LSPAF; 6.6% undetermined) underwent CB PVI and 79 (61.4 ± 8.1 years old; 83.5% male; 41.8% 3D-PAF; 45.5% 3B/3D-persistent AF; 12.7% 3C/3D-LSPAF) underwent hybrid procedure. Arrhythmia freedom through 36 months was 55.2% for CB PVI and 50.4% for hybrid (p = .32). Class I AAD utilization at discharge occurred in 38 (19.3%) patients in the CB PVI group and 5 (6.3%) patients in the hybrid group (p = .01). CB PVI class I AAD utilization at 12 months occurred in 14 (9.0) patients versus 0 patients for hybrid convergent (p = .004). Patients with one or more adverse event were as follows: two (1.0%) in the CB PVI group (both transient phrenic nerve palsy) and three (3.7%) in the hybrid group (two with significant bleeding and one with wound infection) (p = .14).

CONCLUSION

This study demonstrated that patients with more complex forms of AF (3D-PAF or 3B/3C/3D-persistent/LSPAF) could be well managed with a convergent approach. In a real-world evaluation, outcomes match safety and efficacy thresholds achieved for patients with earlier, less complex AF etiologies treated by CB PVI alone.

Enlarged right atrium predicts pacemaker implantation after atrial fibrillation ablation in patients with tachycardia-bradycardia syndrome

Introduction

Although catheter ablation (CA) of tachycardia-bradycardia syndrome (TBS) in patients with atrial fibrillation (AF) is considered to be an effective treatment strategy, pacemaker implantations (PMIs) are often required even after a successful CA. This study aimed to elucidate the clinical predictors of a PMI after CA.

Methods

From 2011 to 2020, 103 consecutive patients diagnosed with TBS were retrospectively enrolled in the study. Among the 103 patients, 54 underwent a PMI and 49 CA of AF. During 47.4 ± 35.4 months after 1.4 ± 0.6 CA sessions, 37 (75.5%) of 49 patients were free from atrial arrhythmia recurrences. PMIs were performed in 11 patients (PMI group) and the remaining 38 did not receive a PMI (non-PMI group).

Results

When comparing the PMI and non-PMI groups, there were no differences in the basic mean heart rate (P = 0.36), maximum pauses detected by 24-hour Holter-monitoring (P = 0.61), and other clinical parameters between the two groups while the right atrial area index was larger (42.1 ± 24.0 vs. 21.8 ± 8.4 cm2/m2 P = 0.002) in the PMI group than non-PMI group. The ROC curve analysis showed that the optimal cutoff point of the ratio of the right atrial area index to the left atrial area index for predicting a PMI following CA was 0.812 (Sensitivity 72.7%, specificity 71.1%, positive predictive value 42.1%, negative predictive value 90.0%, diagnostic accuracy 71.4%, AUC = 0.81).

Conclusion

Right atrial enlargement prior to CA was considered to be one of the risk factors for a PMI after CA of AF.

Artificial intelligence software standardizes electrogram-based ablation outcome for persistent atrial fibrillation

INTRODUCTION

Multiple groups have reported on the usefulness of ablating in atrial regions exhibiting abnormal electrograms during atrial fibrillation (AF). Still, previous studies have suggested that ablation outcomes are highly operator- and center-dependent. This study sought to evaluate a novel machine learning software algorithm named VX1 (Volta Medical), trained to adjudicate multipolar electrogram dispersion.

METHODS

This study was a prospective, multicentric, nonrandomized study conducted to assess the feasibility of generating VX1 dispersion maps. In 85 patients, 8 centers, and 17 operators, we compared the acute and long-term outcomes after ablation in regions exhibiting dispersion between primary and satellite centers. We also compared outcomes to a control group in which dispersion-guided ablation was performed visually by trained operators.

RESULTS

The study population included 29% of long-standing persistent AF. AF termination occurred in 92% and 83% of the patients in primary and satellite centers, respectively, p = 0.31. The average rate of freedom from documented AF, with or without antiarrhythmic drugs (AADs), was 86% after a single procedure, and 89% after an average of 1.3 procedures per patient (p = 0.4). The rate of freedom from any documented atrial arrhythmia, with or without AADs, was 54% and 73% after a single or an average of 1.3 procedures per patient, respectively (p < 0.001). No statistically significant differences between outcomes of the primary versus satellite centers were observed for one (p = 0.8) or multiple procedures (p = 0.4), or between outcomes of the entire study population versus the control group (p > 0.2). Interestingly, intraprocedural AF termination and type of recurrent arrhythmia (i.e., AF vs. AT) appear to be predictors of the subsequent clinical course.

CONCLUSION

VX1, an expertise-based artificial intelligence software solution, allowed for robust center-to-center standardization of acute and long-term ablation outcomes after electrogram-based ablation.

Comparative efficacy and safety of different catheter ablation strategies for persistent atrial fibrillation: a network meta-analysis of randomized clinical trials

AIMS

Whereas pulmonary vein isolation (PVI) is the universally agreed target in catheter ablation of paroxysmal atrial fibrillation (AF), an ideal ablation set in persistent AF remains questioned. Aim of this study is to conduct a network meta-analysis (NMA) of randomized clinical trials (RCTs) comparing different ablation strategies in persistent AF patients.

METHODS AND RESULTS

Network meta-analysis was performed in a frequentist framework with the different ablation strategies constituting the competitive arms of interest. Primary efficacy endpoint was recurrences of atrial tachyarrhythmia (AF, atrial flutter, and/or organized atrial tachycardia). Secondary endpoints included major peri-procedural complications, procedure, and fluoroscopy duration. PubMED/MEDLINE and EMBASE databases were searched through June 2020. 2548 records were screened and 57 full-text articles assessed. Eventually 24 RCTs were included, encompassing 3245 patients (median follow-up 15 months, IQR 12-18). Compared to PVI alone, PVI plus linear lesions in the left atrium and elimination of extra-PV sources was the only strategy associated with a reduced risk of arrhythmia recurrence (RR 0.49, 95%CI 0.27-0.88). Most treatment arms were associated with longer procedural time compared with PVI; however, major peri-procedural complications and fluoroscopy time did not differ.

CONCLUSION

A comprehensive strategy including PVI, linear lesions in the left atrium, and elimination of extra-PV sources (constrained by a heterogeneous definition across studies) was associated with reduced risk of recurrent atrial tachyarrhythmias compared to PVI alone. All investigated treatment arms yielded similar safety profiles. Further research should rely on enhanced substrate-based approach definitions to solve one of the most evident knowledge gaps in interventional electrophysiology.

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 .

Very long term outcome after linear versus electrogram guided ablation for persistent atrial fibrillation

The optimal ablation strategy for persistent atrial fibrillation (PsAF) remains to be defined. We sought to compare very long-term outcomes between linear ablation and electrogram (EGM)-guided ablation for PsAF. In a retrospective analysis, long-term arrhythmia-free survival compared between two propensity-score matched cohorts, one with pulmonary vein isolation (PVI) and linear ablation including roof/mitral isthmus line (LINE-group, n = 52) and one with PVI and EGM-guided ablation (EGM-group; n = 52). Overall, 99% of patients underwent successful PVI. Complete block following linear ablation was achieved for 94% of roof lines and 81% of mitral lines (both lines blocked in 75%). AF termination by EGM-guided ablation was accomplished in 40% of patients. Non-PV foci were targeted in 7 (13%) in the LINE-group and 5 (10%) patients in the EGM-group (p = 0.76). During 100 ± 28 months of follow-up, linear ablation was associated with superior arrhythmia-free survival after the initial and last procedure (1.8 ± 0.9 procedures) compared with EGM-group (Logrank test: p = 0.0001 and p = 0.045, respectively). In multivariable analysis, longer AF duration and EGM-guided ablation remained as independent predictors of atrial arrhythmia recurrence. Linear ablation might be a more effective complementary technique to PVI than EGM-guided ablation for PsAF ablation.

Efficacy of LGE-MRI-guided fibrosis ablation versus conventional catheter ablation of atrial fibrillation: The DECAAF II trial: Study design

INTRODUCTION

Success rates of catheter ablation in persistent atrial fibrillation (AF) remain suboptimal. A better and more targeted ablation strategy is urgently needed to optimize outcomes of AF treatment. We sought to assess the safety and efficacy of targeting atrial fibrosis during ablation of persistent AF patients in improving procedural outcomes.

METHODS

The DECAAF II trial (ClinicalTrials. gov identifier number NCT02529319) is a prospective, randomized, multicenter trial of patients with persistent AF. Patients with persistent AF undergoing a first-time ablation procedure were randomized in a 1:1 fashion to receive conventional pulmonary vein isolation (PVI) ablation (Group 1) or PVI + fibrosis-guided ablation (Group 2). Left atrial fibrosis and ablation induced scarring were defined by late gadolinium enhancement magnetic resonance imaging at baseline and at 3-12 months postablation, respectively. The primary endpoint is the recurrence of atrial arrhythmia postablation, including atrial fibrillation, atrial flutter, or atrial tachycardia after the 90-day postablation blanking period. Patients were followed for a period of 12-18 months with a smartphone ECG Device (ECG Check Device, Cardiac Designs Inc.). With an anticipated enrollment of 900 patients, this study has an 80% power to detect a 26% reduction in the hazard ratio of the primary endpoint.

RESULTS AND CONCLUSION

The DECAAF II trial is the first prospective, randomized, multicenter trial of patients with persistent AF using imaging defined atrial fibrosis as a treatment target. The trial will help define an optimal approach to catheter ablation of persistent AF, further our understanding of influencers of ablation lesion formation, and refine selection criteria for ablation based on atrial myopathy burden.

Precise Signals with a High-Density Grid Mapping Catheter Are Useful for an Entrainment Study

Complex atrial tachycardias (ATs) after catheter ablation or a MAZE procedure is sometimes difficult to determine the circuits of the tachycardia. A high-density, grid-shapes mapping catheter has been launched, which can be useful for detecting the detail circuits of tachycardias on three-dimensional mapping systems. The signal quality is also important for performing electrophysiological studies (EPSs), such as entrainment mapping, to identify the circuit. This unique mapping catheter has 1 mm electrodes on 2.5 Fr shafts, which improve the signal quality. The high-quality intracardiac electrograms facilitate differentiating small critical potentials, which allows us to perform detailed entrainment mapping in targeted narrow areas. Here, we describe a patient with a perimetral AT with epi-endocardium breakthrough after a MAZE surgery and catheter ablation, which was treated successfully along with detailed entrainment mapping using the HD Grid. This catheter with high-quality signals could be a significant diagnostic tool for a classic EPS as well as for the construction of 3D mapping.

Recurrent Atrial Fibrillation After Radiofrequency Ablation: What to Expect

Recurrent atrial fibrillation after radiofrequency ablation is observed in up to 50% of patients within 3 months. Early and multiple recurrences predict late recurrences within 1 year, which occurs in 20% to 50% of patients. Although no consensus exists regarding patient selection and timing of redo ablation, we refer symptomatic patients with multiple recurrences and persistent atrial fibrillation for ablation. Reisolation of reconnected pulmonary veins and ablation of nonpulmonary vein triggers is the primary ablation strategy. In addition to repeat ablation, we recommend weight loss, treatment of sleep-disordered breathing, and management of comorbid conditions for durable maintenance of sinus rhythm.

Prevalence and predictive factors of left atrial tachycardia occurring after second-generation cryoballoon ablation of atrial fibrillation

INTRODUCTION

Assess the prevalence and predictors of left atrial tachycardia (LAT) after cryoballoon ablation of pulmonary veins.

METHODS AND RESULTS

Patients who underwent catheter ablation of pulmonary veins with a second-generation cryoballoon for symptomatic paroxysmal (151 of 270, 56%) or persistent (119 of 270, 44%) atrial fibrillation were entered in a single-center prospective registry. Patients who experienced postcryoballoon LAT (pcryo-LAT) were selected on the basis of 12-lead ECG characteristics. Left atrial origin was confirmed during conventional EP study and electroanatomical activation mapping, and patients were treated by RF catheter ablation. Pcryo-LAT was observed in 15 (5.6%) of 270 patients and was attributed to a reentrant mechanism in 11 patients (73%). The other four cases of pcryo-LAT were due to focal atrial tachycardia associated with reconnection of one pulmonary vein. In comparison with patients who remained in sinus rhythm, LA area (HR = 1.09; CI 1.01, 1.2; P = 0.02), LVEF (HR = 0.94; CI 0.90, 0.97; P < 0.001), and LVEF <50% (HR = 8.5; CI 3.1, 23.6; P < 0.001) were predictors of pcryo-LAT. After multivariate Cox analysis, only left ventricular ejection fraction < 50% remained predictive of pcryo-LAT, (HR = 7.8, CI 2.3 26.7, P = 0.002). With a mean survival of 23 months, 73% of patients who experienced pcryo-LAT were in sinus rhythm versus 78% of patients without pcryo-LAT (log rank P = 0.85).

CONCLUSION

The prevalence of pcryo-LAT in patients with atrial fibrillation is low. Left ventricular ejection fraction < 50% is associated with an increased risk of pcryo-LAT. When treated by RF catheter ablation, the presence of pcryo-LAT is not a predictive factor of subsequent recurrence of atrial fibrillation during follow-up.

Combined Cryoballoon and Radiofrequency Ablation Versus Radiofrequency Ablation Alone for Long-Standing Persistent Atrial Fibrillation

BACKGROUND

To achieve sinus rhythm, ablation of long-standing persistent atrial fibrillation (LSPAF) usually requires substrate modification in addition to pulmonary vein isolation (PVI). In the present article, we aimed to compare clinical and substrate modification effects of 2 distinct PVI strategies during stepwise ablation in patients with LSPAF: (1) Combined approach: cryoballoon (CB) for PVI and radiofrequency (RF) ablation for substrate modification and (2) RF-only approach: RF ablation for both PVI and substrate modification.

MATERIALS AND METHODS

A total of 34 patients were divided into 2 groups: 19 in the combined group and 15 in the RF group. Left atrial (LA) complex fractionated atrial electrogram (CFAE) maps were acquired before and after PVI and compared between groups. The groups were compared for acute atrial fibrillation termination (AFT) rates and long-term arrhythmia-free survival.

RESULTS

A significant reduction on total LA CFAE area was observed with PVI in both groups. In the CB group, when pulmonary veins were excluded, the reduction of LA CFAE area was the most significant on the posterior wall of left atrium and which was greater than in the RF group. Although the ratio of AFT was higher in the CB group (44% versus 33%, respectively), single-procedure arrhythmia-free survival at 1 year was comparable between groups (68% in the CB group versus 66% in the RF group). Times of total procedure, fluoroscopy and post-PVI RF were all shorter in the CB group.

CONCLUSIONS

CB may cause greater substrate modification on the posterior wall and increase AFT rate during LSPAF ablation.

Ablation of long-standing persistent atrial fibrillation

Atrial fibrillation (AF) is the most commonly encountered arrhythmia in the clinical setting affecting nearly 6 million people in United States and the numbers are only expected to rise as the population continues to age. Broadly it is classified into paroxysmal, persistent and longstanding persistent AF. Electrical, structural and autonomic remodeling are some of the diverse pathophysiological mechanisms that contribute to the persistence of AF. Our review article emphasizes particularly on long standing persistent atrial fibrillation (LSPAF) aspect of the disease which poses a great challenge for electrophysiologists. While pulmonary vein isolation (PVI) has been established as a successful ablation strategy for paroxysmal AF, same cannot be said for LSPAF owing to its long duration, complexity of mechanisms, multiple triggers and substrate sites that are responsible for its perpetuation. The article explains different approaches currently being adopted to achieve freedom from atrial arrhythmias. These mainly include ablation techniques chiefly targeting complex fractionated atrial electrograms (CFAE), rotors, linear lesions, scars and even considering hybrid approaches in a few cases while exploring the role of delayed enhancement magnetic resonance imaging (deMRI) in the pre-procedural planning to improve the overall short and long term outcomes of catheter ablation.

Electrophysiological Perspectives on Hybrid Ablation of Atrial Fibrillation

To overcome limitations of minimally invasive surgical ablation as a standalone procedure in eliminating atrial fibrillation (AF), hybrid approaches incorporating adjunctive endovascular catheter ablation have been proposed in recent years. The endovascular component targets residual conduction gaps and identifies additional electrophysiological targets with the goal of minimizing recurrent atrial arrhythmia. We performed a systematic review of published studies of hybrid AF ablation, analyzing 432 pooled patients (19% paroxysmal, 29% persistent, 52% long-standing persistent) treated using three different approaches: A. bilateral thoracoscopy with bipolar radiofrequency (RF) clamp-based approach; B. right thoracoscopic suction monopolar RF catheter-based approach; and C. subxiphoid posterior pericardioscopic ("convergent") approach. Freedom from recurrence off antiarrhythmic medications at 12 months was seen in 88.1% [133/151] for A, 73.4% [47/64] for B, and 59.3% [80/135] for C, with no significant difference between paroxysmal (76.9%) and persistent/long-standing persistent AF (73.4%). Death and major surgical complications were reported in 8.5% with A, 0% with B and 8.6% with C. A critical appraisal of hybrid ablation is presented, drawing from experiences and insights published over the years on catheter ablation of AF, with a discussion of the rationale underlying hybrid ablation, its strengths and limitations, where it may have a unique role in clinical management of patients with AF, which questions remain unanswered and areas for further investigation.

Atrial tachycardias following atrial fibrillation ablation

One of the most important proarrhythmic complications after left atrial (LA) ablation is regular atrial tachycardia (AT) or flutter. Those tachycardias that occur after atrial fibrillation (AF) ablation can cause even more severe symptoms than those from the original arrhythmia prior to the index ablation procedure since they are often incessant and associated with rapid ventricular response. Depending on the method and extent of LA ablation and on the electrophysiological properties of underlying LA substrate, the reported incidence of late ATs is variable. To establish the exact mechanism of these tachycardias can be difficult and controversial but correlates with the ablation technique and in the vast majority of cases the mechanism is reentry related to gaps in prior ablation lines. When tachycardias occur, conservative therapy usually is not effective, radiofrequency ablation procedure is mostly successful, but can be challenging, and requires a complex approach.

Efficacy of Catheter Ablation for Persistent Atrial Fibrillation

Background—

Catheter ablation (CA) is commonly performed for persistent atrial fibrillation, but few high-quality randomized controlled trials (RCTs) exist, leading to funding restrictions being proposed in several countries. We performed a random-effects meta-analysis of RCTs and non-RCTs to assess the efficacy of CA for persistent atrial fibrillation.

Methods and Results—

We systematically searched PubMed, EMBASE, CENTRAL, OpenGrey, and clinicaltrials.gov for RCTs and non-RCTs reporting clinical outcomes after CA for persistent atrial fibrillation. Forty-six eligible studies were identified containing 3819 patients. After a single procedure, CA significantly reduced the risk of recurrent atrial fibrillation compared with medical therapy (odds ratio [OR], 0.32; 95% confidence interval [CI], 0.20–0.53; P <0.001). Outcomes were better if the pulmonary veins were encircled (OR, 0.26; 95% CI, 0.09–0.74; P =0.01), and electrical isolation reduced AF recurrence compared with purely anatomic encirclement (OR, 0.33; 95% CI, 0.13–0.86; P =0.02). Linear ablation within the left atrium (OR, 0.22; 95% CI, 0.10–0.49; P <0.001), but not complex fractionated atrial electrogram ablation (OR, 0.64; 95% CI, 0.35–1.18; P =0.15), significantly reduced AF recurrence. Results were not improved by performing more extensive linear lesion sets (OR, 0.77; 95% CI, 0.41–1.43; P =0.40) or from biatrial ablation (OR, 0.62; 95% CI, 0.31–1.24; P =0.17). Where data were available, the relative benefits seen held true both after a single or multiple procedure(s). Sensitivity analyses showed that inclusion of non-RCTs increased statistical power without biasing the calculated effect sizes.

Conclusions—

For patients with persistent atrial fibrillation, CA achieves significantly greater freedom from recurrent atrial fibrillation compared with medical therapy. The most efficacious strategy is likely to combine isolation of the pulmonary veins with limited linear ablation within the left atrium.

Clinical outcome of ablation for long-standing persistent atrial fibrillation with or without defragmentation

OBJECTIVE

To assess the outcome and associated risks of atrial defragmentation for the treatment of long-standing persistent atrial fibrillation (LSP-AF).

METHODS

Thirty-seven consecutive patients (60.4 ± 7.3 years; 28 male) suffering from LSP-AF who underwent pulmonary vein isolation (PVI) and linear ablation were compared. All patients were treated with the Stereotaxis magnetic navigation system (MNS). Two groups were distinguished: patients with (n = 20) and without (n = 17) defragmentation. The primary endpoint of the study was freedom of AF after 12 months. Secondary endpoints were AF termination, procedure time, fluoroscopy time and procedural complications. Complications were divided into two groups: major (infarction, stroke, major bleeding and tamponade) and minor (fever, pericarditis and inguinal haematoma).

RESULTS

No difference was seen in freedom of AF between the defragmentation and the non-defragmentation group (56.2 % vs. 40.0 %, P = 0.344). Procedure times in the defragmentation group were longer; no differences in fluoroscopy times were observed. No major complications occurred. A higher number of minor complications occurred in the defragmentation group (45.0 % vs. 5.9 %, P = 0.009). Mean hospital stay was comparable (4.7 ± 2.2 vs. 3.4 ± 0.8 days, P = 0.06).

CONCLUSION

Our study suggests that complete defragmentation using MNS is associated with a higher number of minor complications and longer procedure times and thus compromises efficiency without improving efficacy.

Long-term outcomes of adjunctive complex fractionated electrogram ablation to pulmonary vein isolation as treatment for non-paroxysmal atrial fibrillation

PURPOSE

The adjunctive ablation of areas of complex fractionated electrogram (CFE) to pulmonary vein isolation (PVI) is an emerging strategy for patients with non-paroxysmal atrial fibrillation (AF). We studied the long-term outcomes of this approach.

METHODS

Sixty-six patients (mean age 58 ± 9, 86.4 % male) with non-paroxysmal AF underwent ablation procedures consisting of PVI plus extensive CFE ablation. Post-ablation atrial tachycardia (AT) was also targeted if presented. All patients were followed up regularly on an ambulatory basis by means of ECG and Holter recordings.

RESULTS

After a mean follow-up period of 40 ± 14 months and 1.7 ± 0.7 procedures, 38 patients (57.6 %) were free of arrhythmias, 15 (22.7 %) displayed clinical improvement and 13 (19.7 %) suffered recurrences of persistent AF/AT. Females displayed poorer long-term outcomes than males (arrhythmia-free 22.2 vs. 63.2 %, p < 0.05). Multivariate analysis demonstrated that long duration of uninterrupted AF prior to the procedure was an additional predictor of long-term failure (odds ratio 1.49, p < 0.01). ROC analysis (area under curve 0.80; p < 0.001) estimated 3.5 years as the optimal cut-off point for predicting long-term failure (sensitivity 85 %, specificity 74 %). The cumulative data showed a significantly higher percentage of arrhythmia-free patients when the duration of AF had been ≤ 2 years (69.7 %) and ≤ 4 years (68.9 %) than when it was > 4 years (33.3 %; p < 0.01).

CONCLUSIONS

PVI + CFE ablation in non-paroxysmal AF appears to provide a reasonable proportion of arrhythmia-free patients during long-term follow-up. Poorer long-term results can be expected among female patients and those with an uninterrupted AF duration of > 4 years.

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.

Contemporary approaches to persistent atrial fibrillation

Atrial fibrillation (AF) is currently the most commonly treated cardiac arrhythmia. It is generally a progressive disease, often more difficult to control as electromechanical remodeling alters the underlying substrate. Patients typically evolve from infrequent, self-terminating episodes, to more frequent and sustained events. In addition, atrial remodeling may make sinus rhythm more challenging to achieve. Although an ablation strategy limited to pulmonary vein isolation may be curative in those with paroxysmal AF, a more extensive approach is often required in those with persistent AF. This article discusses the current approaches and most recent advances in the ablation of persistent and long-standing persistent AF.

Evaluation of linear lesions in the left and right atrium in ablation of long-standing atrial fibrillation

BACKGROUND

This randomized prospective study compared three ablation strategies in patients with long-standing persistent atrial fibrillation (LPeAF). It also explored the best procedural endpoint from among the following: circumferential pulmonary vein isolation (PVI) + left atrial (LA) linear lesions (roofline, mitral isthmus) + complex fractionated atrial electrogram (CFAE) ablation, PVI + LA linear lesions + cavotricuspid isthmus (CTI) ablation + CFAE ablation, and PVI + CFAE ablation.

METHODS AND RESULTS

A total of 210 patients with LPeAF referred for catheter ablation were enrolled and randomized into three ablation groups. The patients in group A (n = 70) underwent PVI followed by LA linear and CFAE ablation; in 93% of patients the primary endpoint was achieved (five patients with incomplete linear lesions). Of the 70 patients in group B who were subjected to PVI followed by LA linear, CFAE, and CTI ablations, in 94% of patients the primary endpoint was achieved (four patients with incomplete linear lesions). All patients in group C (n = 70) successfully underwent PVI and CFAE ablation. Direct current cardioversion was performed upon PVI, CFAE elimination, and completion of linear lesions. Patients were followed-up for atrial tachyarrhythmia recurrence for at least 24 months. After a single ablation procedure, group C (36%) exhibited the lowest success compared with group A (54%) and group B (51%) (P = 0.06). At the mean follow-up of 32 ± 9 months after the final ablation procedure, 53 patients (76%) in group A, 53 (76%) in group B, and 41 (59%) in group C were in sinus rhythm without antiarrhythmic drugs (P = 0.03).

CONCLUSIONS

In LPeAF, linear lesions in the LA help improve outcome of ablation, additional CTI ablation does not.

Substrate and Trigger Ablation for Reduction of Atrial Fibrillation Trial-Part II (STAR AF II): design and rationale

BACKGROUND

The optimal ablation approach for patients with persistent atrial fibrillation (AF) remains unknown. In particular, it is unclear if pulmonary vein (PV) antral isolation (PVI) is sufficient as a lone strategy for persistent AF. Furthermore, if additional substrate ablation is to be added, the ideal approach to substrate ablation is yet to be determined.

OBJECTIVE

The aim of this study is to determine the optimal strategy of catheter ablation of persistent AF by comparing the efficacy of 3 strategies: PVI vs PVI plus complex fractionated electrogram (CFE) ablation (PVI + CFE) vs PVI plus linear ablation (PVI + Lines).

STUDY DESIGN

The STAR AF II study (ClinicalTrials.gov NCT01203748) is a prospective, multicenter, randomized trial with a blinded assessment of outcomes. A total of 549 patients will be randomized in a 1:4:4 fashion to one of the investigation arms: PVI, PVI + CFE, and PVI + Lines, respectively. Patients undergoing a first-time ablation procedure for symptomatic, persistent AF that is refractory to at least 1 antiarrhythmic medication will be included. Persistent AF will be defined as a sustained episode lasting >7 days and <3 years. Patients with a left atrial parasternal size ≥60 mm will be excluded. The primary end point is freedom from documented AF >30 seconds at 18 months after 1 or 2 ablation procedures with or without antiarrhythmic medications.

CONCLUSIONS

The STAR AF II study is a randomized trial designed to evaluate the optimal approach for catheter ablation of persistent AF.

Arrhythmia type after persistent atrial fibrillation ablation predicts success of the repeat procedure

BACKGROUND

The aim of the study was to investigate whether the type of arrhythmia recurrence after ablation of persistent atrial fibrillation (AF) has an impact on the maintenance of sinus rhythm after the repeat ablation procedure.

METHODS AND RESULTS

Included were 78 consecutive patients (82% men; mean age, 61±10 years; mean left atrial diameter, 47±4 mm) with persistent AF who underwent ≥1 repeat ablation. The initial ablation procedure had consisted of pulmonary vein isolation with additional substrate modification (ablation of complex fractionated atrial electrograms [n=63] or linear lesions [n=15]). Patients presented for reablation either with persistent atrial tachycardia (AT) (group 1, n=36), persistent AF (group 2, n=37), or paroxysmal AF (group 3, n=5). The primary end point was freedom from any arrhythmia off antiarrhythmic drugs 6 and 9 months after the reablation procedure. Estimated proportions of patients reaching the primary end point were 59% for group 1, 28% for group 2, and 100% for group 3 at 6 months and 51%, 23%, and 100%, for groups 1, 2, and 3, respectively, at 9 months (P=0.002).

CONCLUSIONS

In patients presenting for a repeat procedure after ablation of persistent AF, the occurrence of AT is associated with a significantly better outcome compared with recurrent persistent AF. These results suggest that AT might be considered as a step toward sinus rhythm.