Procedural findings and ablation outcome in patients with atrial fibrillation referred after two or more failed catheter ablations

Acute epicardial pulmonary vein reconnection: Nondurable transmural lesion or late manifestation of conduction through intercaval bundle

INTRODUCTION

Acute pulmonary vein reconnection (PVR) via epicardial fibers can be found during observation period after PV isolation, the characteristics and related factors have not been fully studied. We aimed to investigate the prevalence, locations, electrogram characteristics, and ablation parameters related to acute epicardial pulmonary vein reconnection (AEPVR).

METHODS

Acute PVR was monitored during observation period after PV isolation. AEPVRs were mapped and distinguished from endocardial conduction gaps. The clinical, electrophysiological characteristics and lesion set parameters were compared between patients with and without PVR. They were also compared among AEPVR, gap-related reconnection, and epicardial PVR in repeat procedures.

RESULTS

A total of 56.1% acute PVR were AEPVR, which required a longer waiting period (p < .001) than endocardial gap. The majority of AEPVR were connections from the posterior PV carina to the left atrial posterior wall, followed by late manifestation of intercaval bundle conduction from the right anterior carina to right atrium. AEPVR was similar to epicardial PVR in redo procedures in distribution and electrogram characteristics. Smaller atrium (p < .001), lower impedance drop (p = .039), and ablation index (p = .028) on the posterior wall were independently associated with presence of AEPVR, while lower interlesion distance (p = .043) was the only predictor for AEPVR in acute PVR. An integrated model containing multiple lesion set parameters had the highest predictive ability for AEPVR in receiver operating characteristics analysis.

CONCLUSIONS

Epicardial reconduction accounted for the majority of acute PVR. AEPVR was associated with anatomic characteristics and multiple ablation-related parameters, which could be explained by nondurable transmural lesion or late manifestation of conduction through intercaval bundle.

Convergent approach to persistent atrial fibrillation ablation: long-term single-centre safety and efficacy

Background

Efforts to maintain sinus rhythm in patients with persistent atrial fibrillation (PsAF) remain challenging, with suboptimal long-term outcomes.

Methods

All patients undergoing convergent PsAF ablation at our centre were retrospectively analysed. The Atricure Epi-Sense® system was used to perform surgical radiofrequency ablation of the LA posterior wall followed by endocardial ablation.

Results

A total of 24 patients underwent convergent PsAF ablation, and 21 (84%) of them were male with a median age of 63. Twelve (50%) patients were obese. In total, 71% of patients had a severely dilated left atrium, and the majority (63%) had preserved left ventricular function. All were longstanding persistent. Eighteen (75%) patients had an AF duration of >2 years. There were no endocardial procedure complications. At 36 months, all patients were alive with no new stroke/transient ischaemic attack (TIA). Freedom from documented AF at 3, 6, 12, 18, 24, and 36 months was 83%, 78%, 74%, 74%, 74%, and 61%, respectively. There were no major surgical complications, with five minor complications recorded comprising minor wound infection, pericarditic pain, and hernia.

Conclusions

Our data suggest that convergent AF ablation is effective with excellent immediate and long-term safety outcomes in a real-world cohort of patients with a significant duration of AF and evidence of established atrial remodelling. Convergent AF ablation appears to offer a safe and effective option for those who are unlikely to benefit from existing therapeutic strategies for maintaining sinus rhythm, and further evaluation of this exciting technique is warranted. Our cohort is unique within the published literature both in terms of length of follow-up and very low rate of adverse events.

Progress in atrial fibrillation ablation during 25 years of Europace journal

The first edition of Europace journal in 1999 came right around the time of the landmark publication of the electrophysiologists from Bordeaux, establishing how elimination of ectopic activity from the pulmonary veins (PVs) resulted in a marked reduction of atrial fibrillation (AF). The past 25 years have seen an incredible surge in scientific interest to develop new catheters and energy sources to optimize durability and safety of ablation, as well as study the mechanisms for AF and devise ablation strategies. While ablation in the beginning was performed with classic 4 mm tip catheters that emitted radiofrequency (RF) energy to create tissue lesions, this evolved to using irrigation and contact force (CF) measurement while increasing power. Also, so-called single-shot devices were developed with balloons and arrays to create larger contiguous lesions, and energy sources changed from RF current to cryogenic ablation and more recently pulsed field ablation with electrical current. Although PV ablation has remained the basis for every AF ablation, it was soon recognized that this was not enough to cure all patients, especially those with non-paroxysmal AF. Standardized approaches for additional ablation targets have been used but have not been satisfactory in all patients so far. This led to highly technical mapping systems that are meant to unravel the drivers for the maintenance of AF. In the following sections, the development of energies, strategies, and tools is described with a focus on the contribution of Europace to publish the outcomes of studies that were done during the past 25 years.

Association of isoproterenol infusion during catheter ablation of atrial fibrillation with outcomes: insights from the UC San Diego AF Ablation Registry

BACKGROUND

High-dose isoproterenol infusion is a useful provocative maneuver to elicit triggers of atrial fibrillation (AF) during ablation. We evaluated whether the use of isoproterenol infusion to elicit triggers of AF after ablation is associated with differential outcomes.

METHODS

We performed a retrospective study of all patients who underwent de novo radiofrequency catheter ablation of AF enrolled in the University of California, San Diego AF Ablation Registry. The primary outcome was freedom from atrial arrhythmias on or off antiarrhythmic drugs (AAD).

RESULTS

Of 314 patients undergoing AF ablation, 235 (74.8%) received isoproterenol while 79 (25.2%) did not. Among those who received isoproterenol, 11 (4.7%) had additional triggers identified. There were no statistically significant differences in procedure time (p = 0.432), antiarrhythmic drug use (p = 0.289), procedural complications (p = 0.279), recurrences of atrial arrhythmias on or off AAD [adjusted hazard ratio (AHR) 0.92 (95% CI 0.58-1.46); p = 0.714], all-cause hospitalizations [AHR 1.00 (95% CI 0.60-1.67); p = 0.986], or all-cause mortality [AHR 0.14 (95% CI 0.01-3.52); p = 0.229] between groups.

CONCLUSIONS

In this registry analysis, use of isoproterenol is safe but was not associated with a reduction in recurrence of atrial arrhythmias.

Impact of Colchicine Monotherapy on the Risk of Acute Pericarditis Following Atrial Fibrillation Ablation

BACKGROUND

Acute pericarditis is a known complication of ablation procedures for atrial fibrillation (AF).

OBJECTIVES

This study aimed to evaluate the benefits of colchicine monotherapy in terms of reducing the risk of pericarditis and related hospitalization rate in AF patients undergoing catheter ablation.

METHODS

Consecutive AF patients undergoing first catheter ablation were classified into 3 groups based on their colchicine use: Group 1: no colchicine; group 2: colchicine from 7 days before to 1 month after ablation; and group 3: colchicine from the day of the procedure to 1 month after. Standard institutional protocol was used to follow all patients for 1 year.

RESULTS

A total of 1,075 patients were classified into groups 1 (n = 607), 2 (n = 213), and 3 (n = 255). Symptoms of acute pericarditis were reported in 129 patients (12%): group 1: n = 106 (17.5%); group 2: n = 4 (1.9%); and group 3: n = 19 (7.5%); P < 0.001. Rate of mild-moderate as well as severe pericarditis were significantly lower in group 2. In the multivariable regression analysis, pre- and post-ablation colchicine use was seen to be associated with significantly lower risk of acute pericarditis and related hospitalization compared with the other 2 groups. In addition, at 1-year follow-up, arrhythmia-free survival rate was significantly higher in paroxysmal AF patients receiving colchicine compared with the no-colchicine population.

CONCLUSIONS

Colchicine therapy starting 7 days before to 1 month after the ablation procedure was associated with significantly lower risk of acute pericarditis and related hospitalization. In addition, paroxysmal AF patients receiving colchicine had a higher arrhythmia-free survival rate compared with those not receiving colchicine.

Rationale and study design of the Italian Registry in the setting of Atrial Fibrillation Ablation with Rivaroxaban - IRIS

BACKGROUND

Catheter ablation (CA) of atrial fibrillation (AF) is used routinely to establish rhythm control. There is mounting evidence that CA procedures should be performed during continuous oral anticoagulation and direct oral anticoagulants (DOACs) are considered the first anticoagulation strategy. Few real-life data are now available and even less in the Italian panorama.

METHODS

IRIS is an Italian multicenter, non-interventional, prospective study which will be enrolled consecutive AF patients eligible for CA and treated with Rivaroxaban; patients in treatment with Rivaroxaban proceeded directly to CA while Rivaroxaban-naive patients were scheduled for CA after 4 weeks of uninterrupted anticoagulation unless the exclusion of atrial thrombi. Rivaroxaban was uninterrupted or shortly uninterrupted (<24 hours) prior CA, in line with routinely practice of each operator. Patients will be followed on continuous anticoagulation for 1 month after the ablation. The primary efficacy outcome is the cumulative incidence of all-cause death and systemic embolism while the primary safety outcome is the incidence of major bleeding events. The secondary outcomes are represented by non-major bleeding events. All events must be occurred within the first 30 days after the procedure.

RESULTS

Two hundred fifty patients are expected to be enrolled and the study is estimated to be completed by the end of 2022. Up to now 56 patients have been enrolled.

CONCLUSIONS

This study is the first large Italian prospective study on the management of Rivaroxaban in patients undergoing CA of AF. It aims to depict a comprehensive view of anticoagulation strategy prior CA in several Italian electrophysiology labs.

10-Year Outcomes of Patients With Non-Paroxysmal Atrial Fibrillation Undergoing Catheter Ablation

BACKGROUND

Radiofrequency catheter ablation (RFCA) is commonly performed in patients with non-paroxysmal atrial fibrillation (AF), but because very long-term follow-up results of RFCA are limited, we investigated the 10-year RFCA outcomes of non-paroxysmal AF.Methods and Results: We retrospectively enrolled 100 patients (89 men, mean age 53.5±8.4years) with drug-refractory symptomatic non-paroxysmal AF who underwent 3D electroanatomic-guided RFCA. Procedural characteristics at index procedures and clinical outcomes were investigated. In the index procedures, all patients had pulmonary vein isolation, 56 (56.0%), 48 (48.0%), and 32 (32.0%) underwent additional linear, complex fractionated atrial electrogram (CFAE) and non-pulmonary vein (NPV) foci ablations, respectively. After 124.1±31.7 months, 16 (16%) patients remained in sinus rhythm after just 1 procedure (3 with antiarrhythmic drugs [AAD]) and after multiple (2.1±1.3) procedures in 53 (53.0%) patients (22 with AAD). Left atrial (LA) diameter (hazard ratio HR 1.061; 95% confidence interval (CI) 1.020 to 1.103; P=0.003), presence of NPV triggers (HR 1.634; 95% CI 1.019 to 2.623; P=0.042) and undergoing CFAE ablation (HR 2.003; 95% CI 1.262 to 3.180; P=0.003) in the index procedure were independent predictors for recurrent atrial tachyarrhythmia.

CONCLUSIONS

The 10-year outcomes of single RFCA in non-paroxysmal AF were unsatisfactory. Enlarged LA, presence of NPV triggers, and undergoing CFAE ablation in the index procedure independently predicted single-procedure recurrence. Multiple procedures are required to achieve adequate rhythm control.

Empirical superior vena cava isolation improves outcomes of radiofrequency re-ablation in pulmonary vein isolation non-responders: A 2-center retrospective study in China

Background

Pulmonary vein isolation (PVI) is the standard ablation strategy for treating atrial fibrillation (AF). However, the optimal strategy of a repeat procedure for PVI non-responders remains unclear.

Objective

This study aims to investigate the incidence of PVI non-responders in patients undergoing a repeat procedure, as well as the predictors for the recurrence of repeat ablation.

Methods

A total of 276 consecutive patients who underwent repeat ablation from August 2016 to July 2019 in two centers were screened. A total of 64 (22%) patients with durable PVI were enrolled. Techniques such as low voltage zone modification, linear ablation, non-PV trigger ablation, and empirical superior vena cava (SVC) isolation were conducted.

Results

After the 20.0 ± 9.9 month follow-up, 42 (65.6%) patients were free from atrial arrhythmias. A significant difference was reported between the recurrent and non-recurrent groups in non-paroxysmal AF (50 vs. 23.8%, p = 0.038), diabetes mellitus (27.3 vs. 4.8%, p = 0.02), and empirical superior vena cava (SVC) isolation (28.6 vs. 60.5%, p = 0.019). Multivariate regression analysis demonstrated that empirical SVC isolation was an independent predictor of freedom from recurrence (95% CI: 1.64-32.8, p = 0.009). Kaplan-Meier curve demonstrates significant difference in recurrence between empirical and non-empirical SVC isolation groups (HR: 0.338; 95% CI: 0.131-0.873; p = 0.025).

Conclusion

About 22% of patients in repeat procedures were PVI non-responders. Non-paroxysmal AF and diabetes mellitus were associated with recurrence post-re-ablation. Empirical SVC isolation could potentially improve the outcome of repeat procedures in PVI non-responders.

COVID-19 Vaccine Acceptance Among Pregnant and Lactating Women in Saudi Arabia

Background The acceptance of vaccines among pregnant and breastfeeding women is vital to alleviate the risk of contracting and transmitting coronavirus disease 2019 (COVID-19). Therefore, we aimed to assess the COVID-19 vaccine acceptance among pregnant and breastfeeding/lactating women and the factors associated with the acceptance of the COVID-19 vaccine in Saudi Arabia. Methodology A cross-sectional survey was conducted among pregnant and breastfeeding women living in Saudi Arabia. A 23-item, self-administered questionnaire was used to assess the COVID-19 vaccine acceptance among pregnant or lactating women. Results A total of 160 (53.3%) pregnant women and 140 (46.7%) breastfeeding/lactating mothers participated in the study. When the participants were asked, "Have you been vaccinated or are you planning to take the vaccine during pregnancy or breastfeeding/lactation?" 164 (54.7%) responded with "Yes." When compared with breastfeeding/lactating mothers (54, 38.6%), pregnant women had more concerns about the efficacy and safety of COVID-19 vaccination (77 (48.1%); p = 0.043). The probability of rejecting COVID-19 vaccination was higher among breastfeeding/lactating women with a lower education level than those with a tertiary education level (odds ratio = 3.42, confidence interval = 1.24, 9.45, p = 0.018). Conclusions This study reported high acceptance of COVID-19 vaccination in a sample of breastfeeding/lactating women. Concern about vaccine safety among many pregnant women was the major reason for hesitancy. Factors such as low education, concerns regarding the efficacy and safety of the vaccine, and doctors' (e.g., obstetrician and gynecologist) recommendations for the COVID-19 vaccine were associated with vaccine acceptance.

Catheter Ablation versus Medical Therapy of Atrial Fibrillation in Patients with Heart Failure: An Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: Atrial fibrillation (AF) and heart failure (HF) often coexist and synergistically contribute to an increased risk of hospitalization, stroke, and mortality. Objective: To compare the efficacy of catheter ablation (CA) versus medical therapy (MT) in HF patients with AF. Methods: Electronic databases were queried for randomized controlled trials (RCTs) of CA versus MT of AF in patients with HF. Risk ratios (RRs), mean differences (MDs), and 95% confidence intervals (CIs) were measured using the Mantel−Haenszel method. Results: A total of nine RCTs enrolling 2155 patients met the inclusion criteria. Compared to MT, CA led to a significant reduction in the composite of all-cause mortality and HF hospitalization (24.6% vs. 37.1%; RR: 0.65 (95% CI: 0.53−0.80); p < 0.0001), all-cause mortality (8.8% vs. 13.6%; RR: 0.65 (95% CI: 0.51−0.82); p = 0.0005), HF hospitalization (15.4% vs. 22.4%; (RR: 0.67 (95% CI: 0.54−0.82); p = 0.0001), AF recurrence (31.8% vs. 77.0%; RR: 0.36 (95% CI: 0.24−0.54); p < 0.0001), and cardiovascular (CV) death (4.9% vs. 8.4%; RR: 0.58 (95% CI: 0.39−0.86); p = 0.007). CA improved the left ventricular ejection fraction (MD:4.76% (95% CI: 2.35−7.18); p = 0.0001), 6 min walk test (MD: 20.48 m (95% CI: 10.83−30.14); p < 0.0001), peak oxygen consumption (MD: 3.1 2mL/kg/min (95% CI: 1.01−5.22); p = 0.004), Minnesota Living with Heart Failure Questionnaire score (MD: −6.98 (95% CI: −12−03, −1.93); p = 0.007), and brain natriuretic peptide levels (MD:−133.94 pg/mL (95% CI: −197.33, −70.55); p < 0.0001). Conclusions: In HF patients, AF catheter ablation was superior to MT in reducing CV and all-cause mortality. Further significant benefits occurred within the ablation group in terms of HF hospitalizations, AF recurrences, the systolic function, exercise capacity, and quality of life.

Current Understanding of Atrial Fibrillation Recurrence After Atrial Fibrillation Ablation: From Pulmonary Vein to Epicardium

Recurrence of atrial fibrillation (AF) after catheter ablation is common, with pulmonary vein (PV) reconnection considered the most likely cause. However, technologies such as contact force-sensing, irrigated catheters, and ablation index (AI)-guided ablation strategies have resulted in more durable PV isolation. As a result, it is difficult to predict which patients will develop AF recurrence despite durable PV isolation, with evolving non-PV atrial substrates thought to be a key contributor to late recurrences. Deciphering the complex mechanisms of AF recurrence beyond the cornerstone of PV isolation therefore remains challenging. Recently, there have been several important advances that may lead to better understanding and treatment of this challenging clinical entity: percutaneous epicardial access and mapping, late gadolinium enhancement magnetic resonance imaging (LGE-MRI), improvements in high-resolution electroanatomic mapping, and new ablation energy sources, specifically pulsed-field ablation. This review aims to synthesize the current literature in an effort to better understand arrhythmia mechanisms and treatment targets in patients with AF/Atrial tachycardia (AT) recurrence post-ablation. This article is protected by copyright. All rights reserved.

Targeting non-pulmonary vein triggers in persistent atrial fibrillation: results from a prospective, multicentre, observational registry

AIMS

We evaluated the efficacy of an ablation strategy empirically targeting pulmonary veins (PVs) and posterior wall (PW) and the prevalence and clinical impact of extrapulmonary trigger inducibility and ablation in a large cohort of patients with persistent atrial fibrillation (PerAF).

METHODS AND RESULTS

A total of 1803 PerAF patients were prospectively enrolled. All patients underwent pulmonary vein antrum isolation (PVAI) extended to the entire PW. A standardized protocol was performed to confirm persistent PVAI and elicit any triggers originating from non-PV sites. All non-PV triggers initiating sustained atrial tachyarrhythmias were ablated. Ablation of non-PV sites triggering non-sustained runs (<30 s) of atrial tachyarrhythmias or promoting frequent premature atrial complexes (≥10/min) was left to operator's discretion. Overall, 1319 (73.2%) patients had documented triggers from non-PV areas. After 17.4 ± 8.5 months of follow-up, the cumulative freedom from atrial tachyarrhythmias among patients without inducible non-PV triggers (n = 484) was 70.2%. Patients with ablation of induced non-PV triggers had a significantly higher arrhythmia control than those whose triggers were not ablated (67.9% vs. 39.4%, respectively; P < 0.001). After adjusting for clinically relevant variables, patients in whom non-PV triggers were documented but not ablated had an increased risk of arrhythmia relapse (hazard ratio: 2.39; 95% confidence interval: 2.01-2.83; P < 0.001).

CONCLUSION

Pulmonary vein antrum isolation extended to the entire PW might provide acceptable long-term arrhythmia-free survival in PerAF patients without inducible non-PV triggers. In our population of PerAF patients, non-PV triggers could be elicited in ∼70% of PerAF patients and their elimination significantly improved outcomes.

Natural History of Arrhythmia After Successful Isolation of Pulmonary Veins, Left Atrial Posterior Wall, and Superior Vena Cava in Patients With Paroxysmal Atrial Fibrillation: A Multi-Center Experience

Background We evaluated long-term outcome of isolation of pulmonary veins, left atrial posterior wall, and superior vena cava, including time to recurrence and prevalent triggering foci at repeat ablation in patients with paroxysmal atrial fibrillation with or without cardiovascular comorbidities. Methods and Results A total of 1633 consecutive patients with paroxysmal atrial fibrillation that were arrhythmia-free for 2 years following the index ablation were classified into: group 1 (without comorbidities); n=692 and group 2 (with comorbidities); n=941. We excluded patients with documented ablation of areas other than pulmonary veins, the left atrial posterior wall, and the superior vena cava at the index procedure. At 10 years after an average of 1.2 procedures, 215 (31%) and 480 (51%) patients had recurrence with median time to recurrence being 7.4 (interquartile interval [IQI] 4.3-8.5) and 5.6 (IQI 3.8-8.3) years in group 1 and 2, respectively. A total of 201 (93.5%) and 456 (95%) patients from group 1 and 2 underwent redo ablation; 147/201 and 414/456 received left atrial appendage and coronary sinus isolation and 54/201 and 42/456 had left atrial lines and flutter ablation. At 2 years after the redo, 134 (91.1%) and 391 (94.4%) patients from group 1 and 2 receiving left atrial appendage/coronary sinus isolation remained arrhythmia-free whereas sinus rhythm was maintained in 4 (7.4%) and 3 (7.1%) patients in respective groups undergoing empirical lines and flutter ablation (P<0.001). Conclusions Very late recurrence of atrial fibrillation after successful isolation of pulmonary veins, regardless of the comorbidity profile, was majorly driven by non-pulmonary vein triggers and ablation of these foci resulted in high success rate. However, presence of comorbidities was associated with significantly earlier recurrence.

Impact of Oral Anticoagulation Therapy Versus Left Atrial Appendage Occlusion on Cognitive Function and Quality of Life in Patients With Atrial Fibrillation

Background

We compared the cognitive status and quality of life in patients with atrial fibrillation undergoing left atrial appendage occlusion (LAAO) or remaining on oral anticoagulation (OAC) after atrial fibrillation ablation.

Methods and Results

Cognition was assessed by the Montreal Cognitive Assessment (MoCA) survey at baseline and follow‐up. Consecutive patients receiving LAAO or OAC after atrial fibrillation ablation were screened, and patients with a score of ≤17 were excluded from the study. Quality of life was measured at baseline and 1 year using the Atrial Fibrillation Effect on Quality of Life survey. A total of 50 patients (CHA₂DS₂‐VASc [congestive heart failure, hypertension, age≥75 years, diabetes mellitus, stroke or transient ischemic attack, vascular disease, age 65–74 years, sex category] score: 3.30±1.43) in the LAAO group and 48 (CHA₂DS₂‐VASc score 2.73±1.25) in the OAC group were included in this prospective study. Mean baseline MoCA score was 26.18 and 26.08 in the LAAO and OAC groups, respectively (P=0.846). At 1 year, scores were 26.94 and 23.38 in the respective groups. MoCA score decreased by an estimated −2.74 (95% CI, −3.61 to −1.87; P<0.0001) points in the OAC group, whereas the change in the LAAO group was nonsignificant (0.79; (95% CI, −0.06 to 1.64; P=0.07). After adjusting for baseline clinical characteristics, remaining on OAC was an independent predictor of MoCA change at 1 year (regression coefficient, −3.38; 95% CI, −4.75 to −2.02; P<0.0001). Change in Atrial Fibrillation Effect on Quality of Life score did not differ significantly in achieving a clinically important difference between groups.

Conclusions

In this series, a significant difference in the postprocedure MoCA score was observed in postablation patients with atrial fibrillation receiving LAAO versus remaining on OAC with a substantial decline in the score in the OAC group. However, quality of life improved similarly across groups.

Registration

https://www.ClinicalTrials.gov. Unique identifier: NCT01816308

Flecainide How and When: A Practical Guide in Supraventricular Arrhythmias

Transcatheter ablation was increasingly and successfully used to treat symptomatic drug refractory patients affected by supraventricular arrhythmias. Antiarrhythmic drug treatment still plays a major role in patient management, alone or combined with non-pharmacological therapies. Flecainide is an IC antiarrhythmic drug approved in 1984 from the Food and Drug Administration for the suppression of sustained ventricular tachycardia and later for acute cardioversion of atrial fibrillation and for sinus rhythm maintenance. Currently, flecainide is mostly used for sinus rhythm maintenance in atrial fibrillation (AF) patients without structural cardiomyopathy although recent studies enrolling different patient populations have demonstrated a good effectiveness and safety profile. How should we interpret the results of the CAST after the latest evidence? Is it possible to expand the indications of flecainide, and therefore, its use? This review aims to highlight the main characteristics of flecainide, as well as its optimal clinical use, delineating drug indications and contraindications and appropriate monitoring, based on the most recent evidence.

Predictors of recurrent atrial fibrillation following catheter ablation

INTRODUCTION

Atrial fibrillation (AF) is a complex and multi-factorial rhythm disorder. Catheter ablation is widely used for the management of AF. However, it is limited by relapse of the arrhythmia necessitating repeat procedures.

AREAS COVERED

This review aims to discuss the predictors of post-ablation recurrent AF including age, gender, genetic predisposition, AF type and duration, comorbidities, lifestyle factors, echocardiographic parameters of heart chambers, left atrial fibrosis and ablation strategies and targets. An extensive literature search was undertaken on PubMed and Google Scholar to obtain full texts of relevant AF-related articles.

EXPERT OPINION

Maintenance of stable sinus rhythm is the main intended outcome of AF ablation. Therefore, it is very crucial to identify the risk factors that may influence the ablation success. Most of these predictors such as comorbidities, ablation strategy and targets and lifestyle factors are either reversible or modifiable. Thus, not only the awareness of these known risk factors by both patients and their physicians but also future research to identify the unknown predictors are critical to optimize care in this multi-faceted morbidity.

Anatomical targets and expected outcomes of catheter-based ablation of atrial fibrillation in 2020

Anatomical-based approaches, targeting either pulmonary vein isolation (PVI) or additional extra PV regions, represent the most commonly used ablation treatments in symptomatic patients with atrial fibrillation (AF) recurrences despite antiarrhythmic drug therapy. PVI remains the main anatomical target during catheter-based AF ablation, with the aid of new technological advances as contact force monitoring to increase safety and effective radiofrequency (RF) lesions. Nowadays, cryoballoon ablation has also achieved the same level of scientific evidence in patients with paroxysmal AF undergoing PVI. In parallel, electrical isolation of extra PV targets has progressively increased, which is associated with a steady increase in complex cases undergoing ablation. Several atrial regions as the left atrial posterior wall, the vein of Marshall, the left atrial appendage, or the coronary sinus have been described in different series as locations potentially involved in AF initiation and maintenance. Targeting these regions may be challenging using conventional point-by-point RF delivery, which has opened new opportunities for coadjuvant alternatives as balloon ablation or selective ethanol injection. Although more extensive ablation may increase intraprocedural AF termination and freedom from arrhythmias during the follow-up, some of the targets to achieve such outcomes are not exempt of potential severe complications. Here, we review and discuss current anatomical approaches and the main ablation technologies to target atrial regions associated with AF initiation and maintenance.

Thromboembolic Risk in Atrial Fibrillation Patients With Left Atrial Scar Post-Extensive Ablation: A Single-Center Experience

OBJECTIVES

This study evaluated the association of the post-ablation scar with stroke risk in patients undergoing atrial fibrillation (AF) ablation.

BACKGROUND

Late gadolinium enhancement-cardiac magnetic resonance studies have reported a direct association between pre-ablation left atrial scar and thromboembolic events in patients with AF.

METHODS

Consecutive patients with AF were classified into 2 groups based on the type of ablation performed at the first procedure. Group 1 involved limited ablation (isolation of pulmonary veins, left atrial posterior wall, and superior vena cava); and group 2 involved extensive ablation (limited ablation + ablation of nonpulmonary vein triggers from all sites except left atrial appendage). During the repeat procedure, post-ablation scar (region with bipolar voltage amplitude <0.5 mV) was identified by using 3-dimensional voltage mapping.

RESULTS

A total of 6,297 patients were included: group 1, n = 1,713; group 2, n = 4,584. Group 2 patients were significantly older and had more nonparoxysmal AF. Nineteen (0.3%) thromboembolic events were reported after the first ablation procedure: 9 (1.02%) in group 1 and 10 (0.61%) in group 2 (p = 0.26). At the time of the event, all 19 patients were experiencing arrhythmia. Median time to stroke was 14 (interquartile range: 9 to 20) months in group 1 and 14.5 (interquartile range: 8 to 18) months in group 2. Post-ablation scar data were derived from 2,414 patients undergoing repeat ablation. Mean scar area was detected as 67.1 ± 4.6% in group 2 and 34.9 ± 8.8% in group 1 at the redo procedure (p < 0.001).

CONCLUSIONS

Differently from the cardiac magnetic resonance-detected pre-ablation scar, scar resulting from extensive ablation was not associated with increased risk of stroke compared with that from the limited ablation.

The Clinical Application of the Deep Learning Technique for Predicting Trigger Origins in Patients With Paroxysmal Atrial Fibrillation With Catheter Ablation

Background:

Non–pulmonary vein (NPV) trigger has been reported as an important predictor of recurrence post–atrial fibrillation ablation. Elimination of NPV triggers can reduce the recurrence of postablation atrial fibrillation. Deep learning was applied to preablation pulmonary vein computed tomography geometric slices to create a prediction model for NPV triggers in patients with paroxysmal atrial fibrillation.

Methods:

We retrospectively analyzed 521 patients with paroxysmal atrial fibrillation who underwent catheter ablation of paroxysmal atrial fibrillation. Among them, pulmonary vein computed tomography geometric slices from 358 patients with nonrecurrent atrial fibrillation (1–3 mm interspace per slice, 20–200 slices for each patient, ranging from the upper border of the left atrium to the bottom of the heart, for a total of 23 683 images of slices) were used in the deep learning process, the ResNet34 of the neural network, to create the prediction model of the NPV trigger. There were 298 (83.2%) patients with only pulmonary vein triggers and 60 (16.8%) patients with NPV triggers±pulmonary vein triggers. The patients were randomly assigned to either training, validation, or test groups, and their data were allocated according to those sets. The image datasets were split into training (n=17 340), validation (n=3491), and testing (n=2852) groups, which had completely independent sets of patients.

Results:

The accuracy of prediction in each pulmonary vein computed tomography image for NPV trigger was up to 82.4±2.0%. The sensitivity and specificity were 64.3±5.4% and 88.4±1.9%, respectively. For each patient, the accuracy of prediction for a NPV trigger was 88.6±2.3%. The sensitivity and specificity were 75.0±5.8% and 95.7±1.8%, respectively. The area under the curve for each image and patient were 0.82±0.01 and 0.88±0.07, respectively.

Conclusions:

The deep learning model using preablation pulmonary vein computed tomography can be applied to predict the trigger origins in patients with paroxysmal atrial fibrillation receiving catheter ablation. The application of this model may identify patients with a high risk of NPV trigger before ablation.

Repeat pulmonary vein isolation in patients with atrial fibrillation: low ablation index is associated with increased risk of recurrent arrhythmia

OBJECTIVES

We aimed to investigate the predictors of recurrent arrhythmia after repeated pulmonary vein isolation (PVI) performed in the era of contact force without additional substrate ablation. One of the predictors studied, ablation index (AI), incorporates power, contact force, and time in a weighted formula and is reported to predict lesion size in animals. Design. Consecutive patients (n = 108) undergoing repeat PVI without additional substrate modification using a contact force sensing catheter were included retrospectively at a tertiary center. All ablation points were analyzed offline. A new variable, normalized AI (AI corrected for the location of the lesion-anterior vs. posterior) was calculated. The patients were systematically followed with clinical visit and 12-lead ECG as well as review of the regional electronic patient files at 3 and 12 months after the procedure with 5-day Holter at 12 months. Results. Electrical reconnection to at least one pulmonary vein (PV) was seen in 97% of the patients. The recurrence rate was 35%. There was no recurrence in patients with nAI above 1.15 (n = 26). Patients with electrical reconnection of up to two PVs had a higher risk of recurrence compared with patients having electrical reconnection of three or four PVs (p = .003), and this risk was especially high in patients with persistent atrial fibrillation (69 [39-91]%). Conclusions. The risk of recurrence is higher in patients with ablations performed with low levels of AI and in patients with reconnection to up to two PVs. Our data may indicate the need for higher target levels of AI during repeat PVI than normally used during de-novo PVI.

Treatment of Atrial Fibrillation Using Ablation Index-Guided Contact Force Ablation: A Matching-Adjusted Indirect Comparison to Cryoballoon Ablation

Introduction

Ablation Index, also known as VISITAG SURPOINT™, is a novel lesion-quality marker that improves outcomes in radiofrequency (RF) catheter ablation of atrial fibrillation (AF). There is no direct evidence on the comparative effectiveness of RF ablation with Ablation Index and cryoballoon (CB). The objective of the present study was to conduct a matching-adjusted indirect comparison (MAIC) using individual patient-level data (IPD) to compare the effectiveness of RF ablation with Ablation Index to that of CB on recurrence of atrial arrhythmias 12 months after catheter ablation in patients with paroxysmal AF (PAF).

Methods

Individual patient-level data for RF ablation with Ablation Index were obtained from two studies: Solimene et al. [J Interv Card Electrophysiol 54(1):9–15, 2019] and Hussein et al. [J Cardiovasc Electrophysiol 28(9):1037–1047, 2017]. Comparable CB studies identified from a systematic literature review were pooled. Prognostic variables for adjustment were ranked a priori by several practicing electrophysiologists. In the absence of a common treatment arm between the Ablation Index and CB studies, an unanchored MAIC was conducted. Primary analysis compared the Solimene et al. study to pooled CB studies. A secondary analysis compared pooled RF ablation with Ablation Index studies to pooled CB studies. Several scenario and sensitivity analyses were conducted.

Results

Primary analyses showed statistically significant reductions in the rate of arrhythmia recurrence with RF ablation with Ablation Index compared to CB in unmatched, unadjusted (HR 0.50, 95% CI 0.27–0.95) and matched (0.42, 0.21–0.86) analyses. Greater reductions in the rate of arrhythmia recurrence that favored RF ablation with Ablation Index were observed after matching and adjusting for age (0.41, 0.20–0.85), age and left ventricular ejection fraction (0.37, 0.16–0.88), and age, sex, and left ventricular ejection fraction (0.30, 0.13–0.71). Secondary and sensitivity analyses showed similar reductions.

Conclusions

Radiofrequency ablation with Ablation Index was associated with reductions in recurrence of atrial arrhythmias at 12 months compared to CB in unmatched and unadjusted, matched, and matched and adjusted comparisons.

Electronic Supplementary Material

The online version of this article (10.1007/s12325-019-01173-4) contains supplementary material, which is available to authorized users.

Toward a Uniform Ablation Protocol for Paroxysmal, Persistent, and Permanent Atrial Fibrillation

Atrial fibrillation catheter ablation has emerged as the most effective strategy to restore and maintain sinus rhythm. The cornerstone of atrial fibrillation ablation is elimination of triggers from the pulmonary veins by pulmonary vein isolation. Nevertheless, some patients may experience atrial tachyarrhythmia recurrences even with permanent pulmonary vein antral isolation. Whether and in which patients pulmonary vein antral isolation should be considered as the only ablation strategy remains a matter of debate. This review aims to summarize the rationale and effectiveness of different ablation approaches and identify key points for a uniform atrial fibrillation ablation strategy.

Mapping and Imaging in Non-paroxysmal AF

Despite intense research efforts, maintenance of sinus rhythm in patients with non-paroxysmal AF remains challenging with suboptimal outcomes. A major limitation to the success of current ablation-based treatments is that our understanding of AF pathophysiology is incomplete. Advances in imaging and mapping tools have been reported to improve ablation outcomes. However, the role of these new approaches on the clinical care of patients with AF remains to be validated and better understood before wide adoption can occur. This article reviews the current techniques of imaging and mapping that can be applied in the management of patients with non-paroxysmal AF with a focus on their relevance to catheter ablation. Future applications and opportunities for new knowledge are also discussed.

Catheter ablation for lone atrial fibrillation in individuals aged under 35 years

BACKGROUND

To assess the effectiveness of radiofrequency catheter ablation for lone atrial fibrillation in young adults.

METHODS

This single-centre, retrospective, observational study enrolled 75 consecutive patients (86.7% men) under 35 (median, 30) years old with lone atrial fibrillation (68% paroxysmal, 26.7% persistent, and 5.3% long-standing persistent) without other cardiopulmonary diseases who underwent catheter ablation between April 2009 and May 2017. Procedural endpoints were circumferential pulmonary vein ablation for atrial fibrillation with pulmonary vein trigger, and target ablation or bidirectional block of lines and disappearance of complex fractionated atrial electrograms for atrial fibrillation with clear and unclear non-pulmonary vein triggers, respectively.

RESULTS

Main study outcome was rate of survival free from atrial tachyarrhythmia recurrence, which at median 61 (range, 5-102) months follow-up was 62.7% (64.7 and 58.3% for paroxysmal and non-paroxysmal atrial fibrillation, respectively) after single ablation, and 69.3% (68.6 and 70.8% for paroxysmal and non-paroxysmal atrial fibrillation, respectively) after mean 1.2 ablations (two and three ablations in 11 and 2 patients, respectively). In multivariate analysis, non-pulmonary vein trigger was a significant independent predictor of recurrent atrial tachyarrhythmia (OR, 10.60 [95%CI, 2.25-49.96]; p = 0.003). There were no major periprocedural adverse events.

CONCLUSIONS

In patients under 35 years old with lone atrial fibrillation, radiofrequency catheter ablation appeared effective particularly for atrial fibrillation with pulmonary vein trigger and regardless of left atrial size or atrial fibrillation duration or type. Atrial tachyarrhythmia recurrence after multiple ablations warrants further study.

Impact of electrophysiological and pharmacological noninducibility following pulmonary vein isolation in patients with paroxysmal and persistent atrial fibrillation

BACKGROUND

Two methods for testing inducibility of atrial fibrillation (AF)-atrial pacing and isoproterenol infusion-have been proposed to determine the endpoint of catheter ablation. However, the utility of the combination for testing electrophysiological inducibility (EPI) and pharmacological inducibility (PHI) is unclear.

METHODS

After pulmonary vein isolation (PVI), inducibility of atrial tachyarrhythmia was assessed with the dual methods in 291 consecutive patients with AF (65% paroxysmal) undergoing initial catheter ablation.

RESULTS

The incidence of EPI was significantly higher in patients with persistent AF than paroxysmal AF (32.0% vs 11.7%, respectively, P < .001). The incidence of PHI was not significantly different between the two groups (25.2% vs 26.1%, respectively, P = .87). There was no significant difference in AF recurrence according to inducibility in paroxysmal AF. In persistent AF, however, patients achieving neither EPI nor PHI under PVI-only strategy had significantly lower rates of AF recurrence than those achieving either EPI or PHI and consequently requiring additional ablation for inducible atrial tachyarrhythmia (68.5% vs 49.0%, respectively; log-rank test, P = .022). In persistent AF, multivariate Cox regression analysis showed that achieving neither EPI nor PHI was a negative independent predictor of AF recurrence (HR 0.492, 95% CI 0.254-0.916, P = .026).

CONCLUSIONS

Achieving neither EPI nor PHI following PVI was associated with favorable outcome in patients with persistent AF. The combination of tests may discriminate patients responsive to the PVI-only strategy. Further selective approaches are necessary to improve outcome for inducible atrial tachyarrhythmia in patients with persistent AF.

Persistent Atrial Fibrillation Ablation: Where Do We Go From Here?

Catheter ablation is being used increasingly for the treatment of atrial fibrillation (AF). Pulmonary vein antral isolation is considered the "cornerstone" for the ablation of AF. This approach has demonstrated consistent rates of success for paroxysmal AF, but the rates of success for persistent AF are lower. There has long been a hypothesis that additional ablation beyond pulmonary vein isolation is required to achieve better outcomes in the population with persistent AF. However, large clinical trials have demonstrated recently that such approaches as empiric linear ablation and/or ablation of complex fractionated electrograms may add no benefit over pulmonary vein isolation alone in persistent AF. Furthermore, new technologies are improving the durability and outcome of pulmonary vein isolation alone. These observations have endorsed a search for new potential targets for adjuvant ablation, which currently include ablation of dynamic phenomena during AF such as rotational and focal activations, ablation of scar regions in the atria, isolation of the left atrial posterior wall, and ablation of nonpulmonary vein triggers. Whether any of these additional approaches will add to the success of ablation for persistent AF is unknown. Smaller study results are mixed. Only the performance of large-scale randomized trials will definitively answer whether additional ablation over pulmonary vein isolation alone with improve outcomes for persistent AF.

Percutaneous Treatment of Non-paroxysmal Atrial Fibrillation: A Paradigm Shift from Pulmonary Vein to Non-pulmonary Vein Trigger Ablation?

Pulmonary vein antrum isolation is the most effective rhythm control strategy in patients with paroxysmal AF. However, catheter ablation of non-paroxysmal AF has a lower success rate, even when persistent isolation of pulmonary veins (PVs) is achieved. As a result of arrhythmia-related electophysiological and structural changes in the atria, sites other than the PVs can harbour triggers. These non-PV triggers contribute to AF relapse. In this article, we summarise the rationale and current evidence supporting the arrhythmogenic role of non-PV triggers and our ablation approach to patients with non-paroxysmal AF.