Comparison of antiarrhythmic drug therapy and radiofrequency catheter ablation in patients with paroxysmal atrial fibrillation: a randomized controlled trial

2023 Cardiac Society of Australia and New Zealand Expert Position Statement on Catheter and Surgical Ablation for Atrial Fibrillation

Catheter ablation for atrial fibrillation (AF) has increased exponentially in many developed countries, including Australia and New Zealand. This Expert Position Statement on Catheter and Surgical Ablation for Atrial Fibrillation from the Cardiac Society of Australia and New Zealand (CSANZ) recognises healthcare factors, expertise and expenditure relevant to the Australian and New Zealand healthcare environments including considerations of potential implications for First Nations Peoples. The statement is cognisant of international advice but tailored to local conditions and populations, and is intended to be used by electrophysiologists, cardiologists and general physicians across all disciplines caring for patients with AF. They are also intended to provide guidance to healthcare facilities seeking to establish or maintain catheter ablation for AF.

Micro-Costing Analysis for the Treatment of Atrial Fibrillation: An Economic Evaluation of the First Italian Experience of Same-Day Discharge Protocol for Cryoballoon Atrial Fibrillation Ablation

Background: Atrial fibrillation (AF) is the most common cardiac arrhythmia, and its prevalence is expected to increase further due to the aging population, increasing prevalence of risk factors, improving detection methods, and broadening of catheter ablation indications. Along with limited healthcare resources and bed availability, these reasons led to the development of a same-day discharge (SDD) protocol. The aim of this study was to evaluate the health and economic impact of a routine adoption of same-day discharge after cryoballoon AF ablation. Methods: Consecutive patients with symptomatic and drug-refractory AF scheduled for first-time AF ablation were screened, and if deemed suitable, the SDD protocol was proposed and, if accepted, enrolled in the protocol. Results: A total of 324 patients were screened, and 118 were considered eligible for the SDD pathway. Fifty-two patients accepted the SDD pathway and were included in this study. The analysis showed that the variation in resource consumption associated with cryoablation in SDD is equal to EUR 739.85/patient. The analysis showed that the main cost driver for ordinary hospitalization was represented by the hospital stay, which was calculated to be 36% of the total cost. In total, there was a cost reduction of EUR 38.472 thanks to optimized AF patient management from the standard recovery setting to SDD. Conclusions: SDD after cryoballoon ablation of AF is feasible in selected patients with a standardized protocol.

Using Bayesian statistics in confirmatory clinical trials in the regulatory setting: a tutorial review

Bayesian statistics plays a pivotal role in advancing medical science by enabling healthcare companies, regulators, and stakeholders to assess the safety and efficacy of new treatments, interventions, and medical procedures. The Bayesian framework offers a unique advantage over the classical framework, especially when incorporating prior information into a new trial with quality external data, such as historical data or another source of co-data. In recent years, there has been a significant increase in regulatory submissions using Bayesian statistics due to its flexibility and ability to provide valuable insights for decision-making, addressing the modern complexity of clinical trials where frequentist trials are inadequate. For regulatory submissions, companies often need to consider the frequentist operating characteristics of the Bayesian analysis strategy, regardless of the design complexity. In particular, the focus is on the frequentist type I error rate and power for all realistic alternatives. This tutorial review aims to provide a comprehensive overview of the use of Bayesian statistics in sample size determination, control of type I error rate, multiplicity adjustments, external data borrowing, etc., in the regulatory environment of clinical trials. Fundamental concepts of Bayesian sample size determination and illustrative examples are provided to serve as a valuable resource for researchers, clinicians, and statisticians seeking to develop more complex and innovative designs.

Comparing pulsed field electroporation and radiofrequency ablation for the treatment of paroxysmal atrial fibrillation: design and rationale of the BEAT PAROX-AF randomized clinical trial

AIMS

Using thermal-based energy sources [radiofrequency (RF) energy/cryo energy] for catheter ablation is considered effective and safe when performing pulmonary vein isolation (PVI) in patients with paroxysmal atrial fibrillation (AF). However, treatment success remains limited and complications can occur due to the propagation of thermal energy into non-target tissues. We aim to compare pulsed field ablation (PFA) with RF ablation in terms of efficacy and safety for patients with drug-resistant paroxysmal AF.

METHODS AND RESULTS

The BEAT PAROX-AF trial is a European multicentre, superiority, open-label randomized clinical trial in two parallel groups. A total of 292 participants were recruited in 9 high-volume European clinical centres in 5 countries. Patients with paroxysmal AF were randomized to PFA (FARAPULSE Endocardial Ablation System©, Boston Scientific) or RF using the CLOSE protocol with contact force sensing catheter (SmartTouch© catheter and CARTO© Biosense Webster). The primary endpoint will be the 1-year recurrence of atrial arrhythmia, and the major secondary safety endpoint will be the occurrence of acute (<7 days) procedure-related serious adverse events, or pulmonary vein stenosis, or atrio-oesophageal fistula up to 12 months. Additionally, five sub-studies investigate the effect of PFA on oesophageal safety, cerebral lesions, cardiac autonomic nervous system, durability of PVI as assessed during redo ablation procedures, and atrial and ventricular function. The study began on 27 December 2021 and concluded recruitment on 17 January 2024. Results will be available in mid-2025.

CONCLUSION

The BEAT PAROX-AF trial aims to provide critical insights into the optimal treatment approach for patients with paroxysmal AF.

Validation of a machine learning algorithm to identify pulmonary vein isolation during ablation procedures for the treatment of atrial fibrillation: results of the PVISION study

AIMS

Pulmonary vein isolation (PVI) is the cornerstone of ablation for atrial fibrillation. Confirmation of PVI can be challenging due to the presence of far-field electrograms (EGMs) and sometimes requires additional pacing manoeuvres or mapping. This prospective multicentre study assessed the agreement between a previously trained automated algorithm designed to determine vein isolation status with expert opinion in a real-world clinical setting.

METHODS AND RESULTS

Consecutive patients scheduled for PVI were recruited at four centres. The ECGenius electrophysiology (EP) recording system (CathVision ApS, Copenhagen, Denmark) was connected in parallel with the existing system in the laboratory. Electrograms from a circular mapping catheter were annotated during sinus rhythm at baseline pre-ablation, time of isolation, and post-ablation. The ground truth for isolation status was based on operator opinion. The algorithm was applied to the collected PV signals off-line and compared with expert opinion. The primary endpoint was a sensitivity and specificity exceeding 80%. Overall, 498 EGMs (248 at baseline and 250 at PVI) with 5473 individual PV beats from 89 patients (32 females, 62 ± 12 years) were analysed. The algorithm performance reached an area under the curve (AUC) of 92% and met the primary study endpoint with a sensitivity and specificity of 86 and 87%, respectively (P = 0.005; P = 0.004). The algorithm had an accuracy rate of 87% in classifying the time of isolation.

CONCLUSION

This study validated an automated algorithm using machine learning to assess the isolation status of pulmonary veins in patients undergoing PVI with different ablation modalities. The algorithm reached an AUC of 92%, with both sensitivity and specificity exceeding the primary study endpoints.

Pulsed-field ablation for repeat procedures after failed prior thermal ablation for atrial fibrillation

Background

Pulsed-field ablation (PFA) is a novel nonthermal ablation technology. Its potential value for repeat procedures after unsuccessful thermal ablation for atrial fibrillation has not been assessed.

Objective

The purpose of this study was to summarize our initial experience with patients undergoing repeat procedures using PFA.

Methods

Consecutive patients with arrhythmia recurrences after a prior thermal ablation undergoing a repeat procedure using a multipolar PFA catheter from May 2021 and December 2022 were included. After 3-dimensional electroanatomic mapping, reconnected pulmonary veins (PVs) were reisolated and veins with only ostial isolation wither ablated to widen antral PV isolation. Posterior wall ablation was performed if all PVs were durably isolated or in case of low-voltage areas on the posterior wall at the discretion of the operator. Patients underwent follow-up with 7-day Holter electrocardiography after 3, 6, and 12 months.

Results

A total of 186 patients undergoing a repeat procedure using PFA were included. The median number of previous ablations was 1 (range 1-6). The prior ablation modality was radiofrequency in 129 patients (69.4%), cryoballoon in 51 (27.4%), and epicardial ablation in 6 (3.2%). At the beginning of the procedure, 258 of 744 PVs (35%) showed reconnections. Additional antral ablations were applied in 236 of 486 still isolated veins (49%). Posterior wall ablation was added in 125 patients (67%). Major complications occurred in 1 patient (transient ischemic attack 0.5%). Freedom from arrhythmia recurrence in Kaplan-Meier-analysis was 78% after 6 months and 54% after 12 months.

Conclusion

PFA is a versatile and safe option for repeat procedures after failed prior thermal ablation.

Identification of epicardial connections can improve the success rate of first-pass right pulmonary vein isolation

Background

Epicardial connections between the right pulmonary vein (PV) and the right atrium have been reported.

Objective

The purpose of this study was to evaluate the usefulness of our new pulmonary vein isolation (PVI) strategy with identification of these epicardial connections.

Methods

Overall, 235 patients with atrial fibrillation were included. High-density mapping of the left atrium was performed to identify the earliest activation sites (EASs) before PVI in all patients. With our new strategy, if EASs around the right PV carina were identified, we ablated these sites and performed usual first-pass circumferential PVI. The patients were divided into 2 groups according to the ablation strategy. One hundred fifteen patients underwent first-pass PVI without information on EASs (nonanalyzed group), and 78 patients underwent ablation at EASs around the right PV carina in addition to PVI (analyzed group). After first-pass ablation around the PV antrum, remapping was performed.

Results

High-density mapping before PVI showed that the prevalence of EASs around the right PV carina was 10.9% in all patients (9.6% in the nonanalyzed group, 12.8% in the analyzed group; P = .74. The first-pass right PVI success rate was higher in the analyzed group than in the nonanalyzed group (93.6% vs 82.6%; P = .04). The radiofrequency application time for PVI was significantly shorter in the analyzed group than in the nonanalyzed group (45.6 ± 1.0 minutes vs 51.2 ± 0.9 minutes; P <.05).

Conclusion

Identification of epicardial connections before ablation could improve the success rate of first-pass right PVI.

Lower Recurrence Rates of Atrial Fibrillation and MACE Events After Early Compared to Late Ablation: A Danish Nationwide Register Study

BACKGROUND

Guidelines recommend prioritizing treatment with antiarrhythmic drugs before referral of patients with atrial fibrillation to ablation, delaying a potential subsequent ablation. However, delaying ablation may affect ablation outcomes. We sought to investigate the impact of duration from diagnosis to ablation on the risk of atrial fibrillation recurrence and adverse events.

METHODS AND RESULTS

Using Danish nationwide registries, all patients with first-time ablation for atrial fibrillation were identified and included from 2010 to 2018. Patients were divided into 4 groups by diagnosis-to-ablation time: <1.0 year (early ablation), 1.0 to 1.9 years, 2.0 to 2.9 years, and >2.9 years (late ablation). The primary end point was atrial fibrillation recurrence after the 90-day blanking period, defined by admission for atrial fibrillation, cardioversions, use of antiarrhythmic drugs, or repeat atrial fibrillation ablations. The secondary end point was a composite end point of heart failure, ischemic stroke, or death, and each event individually. The study cohort consisted of 7705 patients. The 5-year cumulative incidence of atrial fibrillation recurrence in the 4 groups was 42.9%, 54.8%, 55.9%, and 58.4%, respectively. Hazard ratios were 1.20 (95% CI, 1.07-1.35), 1.29 (95% CI, 1.13-1.47), and 1.40 (95% CI, 1.28-1.53), respectively, with the early ablation group as reference. The hazard ratio for the combined secondary end point was 1.22 (95% CI, 1.04-1.44) in the late ablation group compared with the early ablation group.

CONCLUSIONS

In patients undergoing ablation for atrial fibrillation, early ablation was associated with a significantly lower risk of atrial fibrillation recurrence. Furthermore, the associated risk of heart failure, ischemic stroke, or death was significantly lower in early-compared with late-ablation patients.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society .

Chinese Guidelines for the Diagnosis and Management of Atrial Fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, significantly impacting patients' quality of life and increasing the risk of death, stroke, heart failure, and dementia. Over the past two decades, there have been significant breakthroughs in AF risk prediction and screening, stroke prevention, rhythm control, catheter ablation, and integrated management. During this period, the scale, quality, and experience of AF management in China have greatly improved, providing a solid foundation for the development of guidelines for the diagnosis and management of AF. To further promote standardized AF management, and apply new technologies and concepts to clinical practice in a timely and comprehensive manner, the Chinese Society of Cardiology of the Chinese Medical Association and the Heart Rhythm Committee of the Chinese Society of Biomedical Engineering have jointly developed the Chinese Guidelines for the Diagnosis and Management of Atrial Fibrillation. The guidelines have comprehensively elaborated on various aspects of AF management and proposed the CHA2DS2-VASc-60 stroke risk score based on the characteristics of AF in the Asian population. The guidelines have also reevaluated the clinical application of AF screening, emphasized the significance of early rhythm control, and highlighted the central role of catheter ablation in rhythm control.

Predictors of long-term outcomes in patients with persistent atrial fibrillation undergoing electrical cardioversion

Introduction

Cardioversion for atrial fibrillation (AF) is routinely implemented in daily practice; however, it can be associated with the development of recurrent AF. In this study we aimed to evaluate the predictors of AF recurrence after electrical cardioversion, and to compare the outcomes of patients with or without AF recurrence during follow-up.

Methods

Patients with persistent AF were enrolled from March 2015 to September 2018. Patients with recurrent AF within 6 months after the index cardioversion were considered as AF recurrence (AFR) group, and those with normal sinus rhythm were defined as normal sinus rhythm (NSR) group. Thereafter, all patients were followed up for the incidence of adverse events, including death, requiring dialysis, coronary artery intervention/surgeries, cerebrovascular events, heart failure, and recurrent AF beyond 6 months.

Results

Of 129 patients, 11 patients had failed cardioversion and 7 patients lost to follow-up. So, 34 and 77 patients were categorized as the NSR and the AFR groups. During a median follow-up time of 54 (46-75) months, there was a trend for a higher incidence of major adverse events in the AFR group compared to the NSR group (P=0.063). Lower body mass index (odds ratio [OR] 0.885, 95% confidence interval [CI] 0.794-0.986, P=0.027) and coarse AF before the index cardioversion (OR 3.846, 95% CI 1.189-12.443, P=0.025) were the independent predictors of recurrent AF.

Conclusion

In patients with persistent AF undergoing cardioversion, the presence of coarse AF and the lower values of body mass index were found to be associated with the AF recurrence.

Pulsed-field vs. cryoballoon vs. radiofrequency ablation: a propensity score matched comparison of one-year outcomes after pulmonary vein isolation in patients with paroxysmal atrial fibrillation

BACKGROUND

Pulsed-field ablation (PFA) has shown favourable data in terms of safety and procedural efficiency for pulmonary vein isolation (PVI). We sought to compare procedural and 1-year follow-up data of patients with paroxysmal atrial fibrillation (AF) undergoing PVI using PFA, cryoballoon ablation (CBA) and radiofrequency ablation (RFA).

METHODS

Consecutive patients with paroxysmal AF undergoing a first PVI with PFA at our institution were included. For comparison, patients with paroxysmal AF undergoing a first PVI with CBA and RFA were selected using a 1:2:2 propensity score matching. The PFA group followed the standard 32-applications lesion-set protocol, the CBA group a time-to-effect plus 2-min strategy, and the RFA group the CLOSE protocol. Patients were followed with 7d-Holter ECGs 3, 6, and 12 months after ablation. The primary endpoint was recurrence of atrial tachyarrhythmia (ATa) following a blanking period of 3 months.

RESULTS

A total of 200 patients were included (PFA n = 40; CBA n = 80; RFA n = 80). Median procedure times were shortest with CBA (75 min) followed by PFA (94 min) and RFA (182 min; p < 0.001). Fluoroscopy dose was lowest with RFA (1.6Gycm2) followed by PFA (5.0Gycm2) and CBA (5.7Gycm2; p < 0.001). After a 1-year follow-up, freedom from ATa recurrence was 85.0% with PFA, 66.2% with CBA and 73.8% with RFA (p = 0.12 PFA vs. CBA; p = 0.27 PFA vs. RFA).

CONCLUSION

In a propensity score matched analysis of patients with paroxysmal AF, freedom from any ATa 1 year after PVI using PFA was favourable and at least as good as for PVI with CBA or RFA.

Catheter ablation versus medical therapy in atrial fibrillation: an umbrella review of meta-analyses of randomized clinical trials

This umbrella review synthesizes data from 17 meta-analyses investigating the comparative outcomes of catheter ablation (CA) and medical treatment (MT) for atrial fibrillation (AF). Outcomes assessed were mortality, risk of hospitalization, AF recurrence, cardiovascular events, pulmonary vein stenosis, major bleeding, and changes in left ventricular ejection fraction (LVEF) and MLHFQ score. The findings indicate that CA significantly reduces overall mortality and cardiovascular hospitalization with high strength of evidence. The risk of AF recurrence was notably lower with CA, with moderate strength of evidence. Two associations reported an increased risk of pulmonary vein stenosis and major bleeding with CA, supported by high strength of evidence. Improved LVEF and a positive change in MLHFQ were also associated with CA. Among patients with AF and heart failure, CA appears superior to MT for reducing mortality, improving LVEF, and reducing cardiovascular rehospitalizations. In nonspecific populations, CA reduced mortality and improved LVEF but had higher complication rates. Our findings suggest that CA might offer significant benefits in managing AF, particularly in patients with heart failure. However, the risk of complications, including pulmonary vein stenosis and major bleeding, is notable. Further research in understudied populations may help refine these conclusions.

Ablation versus medical therapy for patients with atrial fibrillation: An updated meta-analysis

To investigate the effect of ablation compared to medical therapy on clinical outcomes of patients with atrial fibrillation (AF). PubMed, Scopus, Embase, and Web of Science databases were searched using ablation, medical treatment, AF, and related words. The effect of ablation and medical therapy was sought to be gathered on stroke or transitional ischemic attack, mortality, hospitalization, recurrence of AF, progression of AF, and left ventricular ejection fraction. Analyses were performed using R software. 31 studies (the results of 27 randomized controlled trials), compromising an overall 6965 patients (Ablation, n = 3643; Medical treatment, n = 3322) were reviewed in our study, revealed that catheter ablation would result in substantial benefits for patients with AF without significant difference in serious adverse events compared to medical management (Risk Ratio: 0.92, [95% Confidence Interval (CI), 0.64-1.33]). Catheter ablation in patients with AF significantly resulted in a 29% reduction in all-cause mortality (RR: 0.71, [95% CI, 0.57-0.88]), a 57% reduction in hospitalization (RR: 0.43, [95% CI, 0.27-0.67]), a 53% reduction in AF recurrence (RR: 0.47, [95% CI, 0.36-0.61]), and a dramatic reduction, 89%, in progression of paroxysmal to persistent AF (RR: 0.11, [95% CI, 0.02-0.65]); also associated with a remarkable improvement in their left ventricular ejection fraction (LVEF) (Mean Difference, MD: 6.84%, [95% CI, 3.27-10.42]) compared to medical therapy. Our study showed that ablation may be superior to medical therapy in patients with AF regarding AF recurrence, mortality, LVEF improvement, hospitalization, and AF progression outcomes.

Association between catheter ablation of atrial fibrillation and mortality or stroke

OBJECTIVE

Catheter ablation of atrial fibrillation effectively reduces symptomatic burden. However, its long-term effect on mortality and stroke is unclear. We investigated if patients with atrial fibrillation who undergo catheter ablation have lower risk for all-cause mortality or stroke than patients who are managed medically.

METHODS

We retrospectively included 5628 consecutive patients who underwent first-time catheter ablation for atrial fibrillation between 2008 and 2018 at three major Swedish electrophysiology units. Control individuals with an atrial fibrillation diagnosis but without previous stroke were selected from the Swedish National Patient Register, resulting in a control group of 48 676 patients. Propensity score matching was performed to produce two cohorts of equal size (n=3955) with similar baseline characteristics. The primary endpoint was a composite of all-cause mortality or stroke.

RESULTS

Patients who underwent catheter ablation were healthier (mean CHA2DS2-VASc score 1.4±1.4 vs 1.6±1.5, p<0.001), had a higher median income (288 vs 212 1000 Swedish krona [KSEK]/year, p<0.001) and had more frequently received university education (45.1% vs 28.9%, p<0.001). Mean follow-up was 4.5±2.8 years. After propensity score matching, catheter ablation was associated with lower risk for the combined primary endpoint (HR 0.58, 95% CI 0.48 to 0.69). The result was mainly driven by a decrease in all-cause mortality (HR 0.51, 95% CI 0.41 to 0.63), with stroke reduction showing a trend in favour of catheter ablation (HR 0.75, 95% CI 0.53 to 1.07).

CONCLUSIONS

Catheter ablation of atrial fibrillation was associated with a reduction in the primary endpoint of all-cause mortality or stroke. This result was driven by a marked reduction in all-cause mortality.

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Patients With Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

Characteristics of right pulmonary vein with an epicardial connection needing additional carina ablation for isolation

Background

This study thought to elucidate the anatomical features that can predict an epicardial connection (EC) between the right pulmonary vein (RPV) and right atrium.

Methods

We retrospectively analyzed 251 consecutive patients undergoing initial radiofrequency pulmonary vein isolation. We defined EC as present when RPV could not be isolated with circumferential ablation and additional ablation for the conduction gap if needed, and RPV isolation could be achieved by ablation for the earliest activation site >10 mm inside the initial ablation line. Using computed tomography data, we evaluated the RPV bifurcation angle, and the area occupation ratio of the carina region to the RPV antrum (ARC) for predicting EC. In subjects with EC undergoing RPV activation mapping after circumferential ablation, the correlation between conduction delay and bipolar/unipolar potential voltage in the carina region was investigated.

Results

There were ECs in 45 out of 251 patients (17.9%). The RPV bifurcation angle (47.7° vs. 38.8°, p < .001) and ARC (37.2% vs. 29.7%, p < .001) were significantly greater in the EC (+) group. Multivariate logistic regression analysis revealed that RPV bifurcation angle (odds ratio [OR]: 1.994, p = .002) and ARC (OR: 3.490, p = .013) were independent predictors of EC. In nine patients with EC undergoing carina region mapping, the unipolar potential voltage was correlated with conduction delay in RPV with EC (R = -0.401, p < .001).

Conclusion

Anatomical features suggesting a wider RPV carina region could predict the presence of EC, and potential with high voltage could be helpful for detecting EC connection sites.

Catheter ablation in patients with paroxysmal atrial fibrillation and absence of structural heart disease: A meta-analysis of randomized trials

Introduction

Rhythm control strategy in paroxysmal atrial fibrillation (AF) can be performed with antiarrhythmic drugs (AAD) or catheter ablation (CA). Nevertheless, a clear overview of the percentage of freedom from AF over time and complications is lacking. Therefore, we conducted a meta-analysis of randomized controlled trials (RCTs) comparing CA versus AAD.

Methods

We searched databases up to 5 May 2023 for RCTs focusing on CA versus AAD. The study endpoints were atrial tachyarrhythmia (AT) recurrence, progression to persistent AF, overall complications, stroke/TIA, bleedings, heart failure (HF) hospitalization and all-cause mortality.

Results

Twelve RCTs enrolling 2393 patients were included. CA showed a significantly lower AT recurrence rate at one year [27.4 % vs 56.3 %; RR: 0.45; p < 0.00001], at two years [39.9 % vs 62.7 %; RR: 0.56; p = 0.0004] and at three years [45.7 % vs 80.9 %; RR: 0.54; p < 0.0001] compared to AAD. Furthermore, CA significantly reduced the progression to persistent AF [1.6 % vs 12.9 %; RR: 0.14; p < 0.00001] with no differences in overall complications [5.9 % vs 4.5 %; RR: 1.27; p = 0.22], stroke/TIA [0.6 % vs 0.6 %; RR: 1.10; p = 0.86], bleedings [0.4 % vs 0.6 %; RR: 0.90; p = 0.84], HF hospitalization [0,3% vs 0,7%; RR: 0.56; p = 0.37] and all-cause mortality [0,4% vs 0.5 %; RR: 0.78; p = 0.67]. Subgroup analysis between radiofrequency and cryo-ablation or considering RCTs with CA as first-line treatment showed no significant differences.

Conclusion

CA demonstrated lower rates of AT recurrence over the time, as well as a significant reduction in the progression from paroxysmal to persistent AF, with no difference in terms of energy source, complications, and clinical outcomes.

50-W vs 40-W During High-Power Short-Duration Ablation for Paroxysmal Atrial Fibrillation: A Multicenter Prospective Study

BACKGROUND

High-power short-duration (HPSD) radiofrequency ablation of atrial fibrillation (AF) increases first-pass pulmonary vein isolation (PVI) and freedom from atrial arrhythmias while decreasing procedural time. However, the optimal power setting in terms of safety and efficacy has not been determined.

OBJECTIVES

This study compared the procedural characteristics and clinical outcomes of 50-W vs 40-W during HPSD ablation of paroxysmal AF.

METHODS

Patients from the REAL-AF prospective multicenter registry (Real-World Experience of Catheter Ablation for Treatment of Symptomatic Paroxysmal and Persistent Atrial Fibrillation) undergoing HPSD ablation of paroxysmal AF, either using 50-W or 40-W, were included. The primary efficacy outcome was freedom from all-atrial arrhythmias. The primary safety outcome was the occurrence of any procedural complication at 12 months. Secondary outcomes included procedural characteristics, AF-related symptoms, and the occurrence of transient ischemic attack or stroke at 12 months.

RESULTS

A total of 383 patients were included. Freedom from all-atrial arrhythmias at 12 months was 80.7% in the 50-W group and 77.3% in the 40-W group (Log-rank P = 0.387). The primary safety outcome occurred in 3.7% of patients in the 50-W group vs 2.8% in the 40-W group (P = 0.646). The 50-W group had a higher rate of first-pass PVI (82.3% vs 76.2%; P = 0.040) as well as shorter procedural (67 minutes [IQR: 54-87.5 minutes] vs 93 minutes [IQR: 80.5-111 minutes]; P < 0.001) and radiofrequency ablation times (15 minutes [IQR: 11.4-20 minutes] vs 27 minutes [IQR: 21.5-34.6 minutes]; P < 0.001) than the 40-W group.

CONCLUSIONS

There was no significant difference in freedom from all-atrial arrhythmias or procedural safety outcomes between 50-W and 40-W during HPSD ablation of paroxysmal AF. The use of 50-W was associated with a higher rate of first-pass PVI as well as shorter procedural times.

Catheter ablation and lower risk of incident dementia and mortality in older adults with atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) has consistently been associated with a higher risk of incident dementia. Observational evidence has suggested catheter ablation may be associated with a lower risk of dementia in patients with AF, but further research is needed. The objectives of this study were to use a global health research network to examine associations between catheter ablation, incident dementia and mortality in older adults with AF, and amongst subgroups by age, sex, co-morbidity status, and oral anticoagulant use.

METHODS

The research network primarily included healthcare organizations in the United States. This network was searched on 28th September 2022 for patients aged ≥65 years with a diagnosis of AF received at least 5 years prior to the search date. Cox proportional hazard models were run on propensity-score matched cohorts.

RESULTS

After propensity score matching, 20,746 participants (mean age 68 years; 59% male) were included in each cohort with and without catheter ablation. The cohorts were well balanced for age, sex, ethnicity, co-morbidities, and cardiovascular medications received. The risk of dementia was significantly lower in the catheter ablation cohort (Hazard Ratio 0.52, 95% confidence interval: 0.45-0.61). The catheter ablation cohort also had a lower risk of all-cause mortality (Hazard Ratio 0.58, 95% confidence interval: 0.55-0.61). These associations remained in subgroup analyses in individuals aged 65-79 years, ≥80 years, males, females, participants who received OACs during follow-up, participants with paroxysmal and non-paroxysmal AF, and participants with and without hypertension, diabetes mellitus, ischemic stroke, chronic kidney disease and heart failure, including heart failure with preserved ejection fraction and heart failure with reduced ejection fraction.

CONCLUSION

The observed lower risk of dementia and mortality with catheter ablation could be an important consideration when determining appropriate patient-centered rhythm control strategies for patients with AF. Further studies including data on the success of ablation are required.

Comparison of the PolarX and the Arctic Front cryoballoon for pulmonary vein isolation in patients with symptomatic paroxysmal atrial fibrillation (COMPARE CRYO) - Study protocol for a randomized controlled trial

INTRODUCTION

Single-shot devices are increasingly used for pulmonary vein isolation (PVI) in atrial fibrillation (AF). The Arctic Front cryoballoon (Medtronic) is the most frequently used single-shot technology. A recently developed novel cryoballoon has been introduced (PolarX, Boston Scientific) with the aim to address limitations of the Arctic Front system.

METHODS

COMPARE CRYO is a multicentre, randomized, controlled trial with blinded endpoint adjudication by an independent clinical events committee. A total of 200 patients with paroxysmal AF undergoing their first PVI are randomized 1:1 between PolarX cryoballoon ablation and Arctic Front cryoballoon ablation. Continuous monitoring during follow-up is performed using an implantable cardiac monitor (ICM) in all patients. The primary endpoint is time to first recurrence of any atrial tachyarrhythmia (AF, atrial flutter, and/or atrial tachycardia) ≥ 120 s between days 91 and 365 post ablation as detected on the (ICM). Procedural safety is assessed by a composite of cardiac tamponade, persistent phrenic nerve palsy >24 h, vascular complications requiring intervention, stroke/transient ischemic attack, atrioesophageal fistula or death occurring during or up to 30 days after the procedure. Key secondary endpoints include (1) procedure and fluoroscopy times, (2) AF burden, (3) proportion of patients with recurrence in the blanking period, (4) proportion of patients undergoing repeat ablation, and (5) quality of life changes at 12 months compared to baseline.

CONCLUSION

COMPARE CRYO will compare the efficacy and safety of the novel PolarX cryoballoon and the standard-of-practice Arctic Front cryoballoon for first PVI performed in patients with symptomatic paroxysmal AF.

TRIAL REGISTRATION

(ClinicalTrials.gov ID: NCT04704986).

How to ablate the septo-pulmonary bundle: a case-based review of percutaneous ablation strategies to achieve roof line block

Electrical conduction through cardiac muscle fibres separated from the main myocardial wall by layers of interposed adipose tissue are notoriously difficult to target by endocardial ablation alone. They are a recognised important cause for procedural failure due to the difficulties of delivering sufficient energy via the endocardial radiofrequency catheter to reach the outer epicardial layer without risking adverse events of the otherwise thin walled atria. Left atrial ablations for atrial fibrillation (AF) and tachycardia are commonly affected by the presence of several epicardial structures, with the septo-pulmonary bundle (SPB), Bachmann's bundle, and the ligament of Marshall all posing substantial challenges for endocardial procedures. Delivery of a transmural lesion set is essential for sustained pulmonary vein isolation and for conduction block across linear atrial lines which in turn has been described to translate into a reduced AF/atrial tachycardia recurrence rate. To overcome the limitations of endocardial-only approaches, surgical ablation techniques for epicardial or combined hybrid endo-epicardial ablations have been described to successfully target these connections. Yet, these techniques confer an increase in procedure complexity, duration, cost, and morbidity. Alternatively, coronary venous system ethanol ablation has been successfully employed by sub-selecting the vein of Marshall to facilitate mitral isthmus line block, although this approach is naturally limited to this area by the coronary venous anatomy. Increased awareness of the pathophysiological relevance of these epicardial structures and their intracardiac conduction patterns in the era of high-resolution 3D electro-anatomical mapping technology has allowed greater understanding of their contribution to the persistence of AF as well as failure to achieve transmural block by traditional ablation approaches. This might translate into novel catheter ablation strategies with procedural success rates comparable to surgical 'cut-and-sew' techniques. This review aims to give an overview of percutaneous catheter ablation strategies to target the SPB, an important cause of failed block across the roof line and isolation of the left atrial posterior wall and/or the pulmonary veins. Existing and investigational technologies will be discussed and an outlook of future approaches provided.

Impact of SGLT2 Inhibitors on AF Recurrence After Catheter Ablation in Patients With Type 2 Diabetes

BACKGROUND

The effects of sodium-glucose cotransporter 2 inhibitors (SGLT2-Is) on recurrent atrial fibrillation (AF) among patients undergoing catheter ablation is not well described.

OBJECTIVES

This study sought to assess the impact of SGLT2-Is on the recurrence of AF among patients with type 2 diabetes mellitus (DM) after catheter ablation.

METHODS

Using the TriNetX research network, we identified, by means of Current Procedural Terminology codes, patients ≥18 years of age with type 2 diabetes mellitus (DM) who had undergone AF ablation from April 1, 2014, to November 30, 2021. Patients were stratified based on the baseline SGLT2-I use. Propensity-score matching resulted in 2,225 patients in each cohort. The primary outcome was a composite of cardioversion, new antiarrhythmic drug (AAD) therapy, or re-do AF ablation after a blanking period after the index ablation. Additional outcomes included heart failure exacerbations, ischemic stroke, all-cause hospitalization, and death during 12 months of follow-up.

RESULTS

SGLT2-I use in patients with type 2 DM undergoing AF ablation was associated with a significantly lower risk of cardioversion, new AAD therapy, and re-do AF ablation (adjusted OR: 0.68; 95% CI: 0.602-0.776; P < 0.0001). At 12 months, patients on SGLT2-Is had a higher probability of event-free survival (HR: 0.85, 95% CI: 0.77-0.95; log-rank test chi-square = 8.7; P = 0.003). All secondary outcomes were lower in the SGLT2I group; however, the ischemic stroke did not differ between groups.

CONCLUSIONS

Use of SGLT2-Is in patients with type 2 DM is associated with a lower risk of arrhythmia recurrence after AF ablation and thence a reduced need for cardioversion, AAD therapy, or re-do AF ablation.

Comparison of the 11-Day Adhesive ECG Patch Monitor and 24-h Holter Tests to Assess the Response to Antiarrhythmic Drug Therapy in Paroxysmal Atrial Fibrillation

Accurate assessment of the response to the antiarrhythmic drug (AAD) in atrial fibrillation (AF) is crucial to achieve adequate rhythm control. We evaluated the effectiveness of extended cardiac monitoring using an adhesive ECG patch in the detection of drug-refractory paroxysmal AF. Patients diagnosed with paroxysmal AF and receiving AAD therapy were enrolled. The subjects simultaneously underwent 11-day adhesive ECG patch monitoring and a 24-h Holter test. The primary study outcome was a detection rate of drug-refractory AF or atrial tachycardia (AT) lasting ≥30 s. A total of 59 patients were enrolled and completed the study examinations. AF or AT was detected in 28 (47.5%) patients by an 11-day ECG patch monitor and in 8 (13.6%) patients by a 24-h Holter test (p < 0.001). The 11-day ECG patch monitor identified an additional 20 patients (33.8%) with drug-refractory AF not detected by the 24-h Holter, and as a result, the treatment plan was changed in 11 patients (10 catheter ablations, one medication change). In conclusion, extended cardiac rhythm monitoring using an adhesive ECG patch in patients with paroxysmal AF under AAD therapy led to over a threefold higher detection of drug-refractory AF episodes, compared to the 24-h Holter test.

Variations in Atrial Fibrillation Ablation Use and Charges in a Modern Cohort of Medicare Beneficiaries

Catheter ablation of atrial fibrillation (CAF) is increasingly being used in the United States. This study aimed to identify variations in CAF use among Medicare beneficiaries (MBs) over a 6-year period (2013 to 2019). Using the Center of Medicare and Medicaid Services database, a 100% sample of MBs who underwent CAF from 2013 to 2019 was included. We stratified CAF use data geographically (Northeast, South, West, and Midwest) and identified the number of CAFs per 100,000 MBs, number of electrophysiologists performing CAFs per 100,000 MBs, number of CAFs per individual electrophysiologist, and average submitted charge for CAF. In addition, we stratified the data per urban versus rural areas and gender of the operator. We found that the mean atrial fibrillation (AF) prevalence, rates of CAFs, number of electrophysiologists performing CAFs, and number of CAFs per electrophysiologist have increased steadily in all regions. The mean AF prevalence was different among regions, with the highest prevalence in the Northeast (p <0.001); however, there was a pattern of higher CAFs rates in the West and the South (p ≥0.057). The number of electrophysiologists performing CAFs was not different among regions; however, the number of CAFs per electrophysiologist was higher in the West and the South (p <0.001). The average submitted charge for CAF has decreased over years and was the lowest in the West and the South (p <0.001). There was no major difference in these variables regarding operator gender. In conclusion, there are significant variations in CAF use among MBs in the United States according to geographic and urban versus rural regions. These variations have the potential to impact the outcomes in MBs diagnosed with AF.

Cryoballoon temperature parameters during cryoballoon ablation predict pulmonary vein reconnection and atrial fibrillation recurrence

BACKGROUND

Cryoballoon ablation (CBA) is an established approach for rhythm management of atrial fibrillation (AF). We sought to assess balloon temperature (BT) parameters as predictors of pulmonary vein (PV) reconnection within the index procedure and AF recurrence following CBA.

METHODS

BT was monitored in 119 AF patients undergoing CBA. PVs were assessed for reconnection during the procedure and patients were followed for arrhythmia recurrence.

RESULTS

PV reconnection was identified in 39 (8.3%) of 471 PVs. BT was significantly colder in the absence of PV reconnection (30 s: - 33.5 °C [- 36; - 30] vs - 29.5 °C [- 35; - 25.5], p = 0.001; 60 s: - 41 °C [- 44; - 37] vs - 36.5 °C [- 42; - 33.5], p < 0.001; nadir: - 47 °C [- 52; - 43] vs - 41.5 °C [- 47; - 38], p < 0.001). PV reconnection was associated with significantly longer time to reach - 15 °C and - 40 °C (14.5 s [11.5-18.5] vs 12 s [10-15.5], p = 0.023; and 75 s [40-95.5] vs 46 s [37-66.75], p = 0.005) and shorter rewarming time (5.75 s [4.75-8.5] vs 7 s [6-9], p = 0.012). ROC analysis of these procedural parameters had an AUC = 0.71 in predicting PV reconnection. AF recurrence occurred in 51 (42.8%) patients. Kaplan-Meier analysis showed better arrhythmia-free survival for patients in whom BT decreased below - 40 °C in all PVs and patients who had no early PV reconnections, compared to patients in whom BT below - 40 °C was not achieved in at least one PV (log rank = 6.3, p = 0.012) and patients who had PV reconnections (log rank = 4.1, p = 0.043).

CONCLUSIONS

Slower BT decline, warmer BT nadir, and faster rewarming time predict early PV reconnection. Absence of early PV reconnections and BT dropping below - 40 °C in all PVs during CBA are associated with lower rates of AF recurrence.

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.

Catheter ablation of atrial fibrillation using FireMagic TrueForce ablation catheter: The TRUEFORCE trial

BACKGROUND

The use of contact force (CF) sensing catheters has provided a revolutionary improvement in catheter ablation (CA) of atrial fibrillation (AF) in the past decade. However, the success rate of CA for AF remains limited, and some complications still occur.

METHODS

The TRUEFORCE trial (Catheter Ablation of Atrial Fibrillation using FireMagic TrueForce Ablation Catheter) is a multicenter, prospective, single-arm objective performance criteria study of AF patients who underwent their first CA procedure using FireMagic TrueForce ablation catheter.

RESULTS

A total of 120 patients (118 with paroxysmal AF) were included in this study, and 112 patients included in the per-protocol analysis. Pulmonary vein isolation (PVI) was achieved in 100% of the patients, with procedure and fluoroscopy time of 146.63 ± 40.51 min and 12.89 ± 5.59 min, respectively. Freedom from recurrent atrial arrhythmia after ablation was present 81.25% (95% confidence interval [CI]: 72.78%-88.00%) of patients. No severe adverse events (death, stroke/transient ischemic attack [TIA], esophageal fistula, myocardial infarction, thromboembolism, or pulmonary vein stenosis) were detected during the follow-up. Four (4/115, 3.33%) adverse events were documented, including one abdominal discomfort, one femoral artery hematoma, one coughing up blood, and one postoperative palpitation and insomnia.

CONCLUSIONS

This study demonstrated the clinical feasibility of FireMagic force-sensing ablation catheter in CA of AF, with a satisfactory short- and long-term efficacy and safety.

A Focal Ablation Catheter Toggling Between Radiofrequency and Pulsed Field Energy to Treat Atrial Fibrillation

BACKGROUND

Because of its safety, "single-shot" pulsed field ablation (PFA) catheters have been developed for pulmonary vein isolation (PVI). However, most atrial fibrillation (AF) ablation procedures are performed with focal catheters to permit flexibility of lesion sets beyond PVI.

OBJECTIVES

This study sought to determine the safety and efficacy of a focal ablation catheter able to toggle between radiofrequency ablation (RFA) or PFA to treat paroxysmal or persistent AF.

METHODS

In a first-in-human study, a focal 9-mm lattice tip catheter was used for PFA posteriorly and either irrigated RFA (RF/PF) or PFA (PF/PF) anteriorly. Protocol-driven remapping was at ∼3 months postablation. The remapping data prompted PFA waveform evolution: PULSE1 (n = 76), PULSE2 (n = 47), and the optimized PULSE3 (n = 55).

RESULTS

The study included 178 patients (paroxysmal/persistent AF = 70/108). Linear lesions, either PFA or RFA, included 78 mitral, 121 cavotricuspid isthmus, and 130 left atrial roof lines. All lesion sets (100%) were acutely successful. Invasive remapping of 122 patients revealed improvement of PVI durability with waveform evolution: PULSE1: 51%; PULSE2: 87%; and PULSE3: 97%. After 348 ± 652 days of follow-up, the 1-year Kaplan-Meier estimates for freedom from atrial arrhythmias were 78.3% ± 5.0% and 77.9% ± 4.1% for paroxysmal and persistent AF, respectively, and 84.8% ± 4.9% for the subset of persistent AF patients receiving the PULSE3 waveform. There was 1 primary adverse event-inflammatory pericardial effusion not requiring intervention.

CONCLUSIONS

AF ablation with a focal RF/PF catheter allows efficient procedures, chronic lesion durability, and good freedom from atrial arrhythmias-for both paroxysmal and persistent AF. (Safety and Performance Assessment of the Sphere-9 Catheter and the Affera Mapping and RF/PF Ablation System to Treat Atrial Fibrillation; NCT04141007 and NCT04194307).

Overview of Cardiac Arrhythmias and Treatment Strategies

Maintenance of normal cardiac rhythm requires coordinated activity of ion channels and transporters that allow well-ordered propagation of electrical impulses across the myocardium. Disruptions in this orderly process provoke cardiac arrhythmias that may be lethal in some patients. Risk of common acquired arrhythmias is increased markedly when structural heart disease caused by myocardial infarction (due to fibrotic scar formation) or left ventricular dysfunction is present. Genetic polymorphisms influence structure or excitability of the myocardial substrate, which increases vulnerability or risk of arrhythmias in patients. Similarly, genetic polymorphisms of drug-metabolizing enzymes give rise to distinct subgroups within the population that affect specific drug biotransformation reactions. Nonetheless, identification of triggers involved in initiation or maintenance of cardiac arrhythmias remains a major challenge. Herein, we provide an overview of knowledge regarding physiopathology of inherited and acquired cardiac arrhythmias along with a summary of treatments (pharmacologic or non-pharmacologic) used to limit their effect on morbidity and potential mortality. Improved understanding of molecular and cellular aspects of arrhythmogenesis and more epidemiologic studies (for a more accurate portrait of incidence and prevalence) are crucial for development of novel treatments and for management of cardiac arrhythmias and their consequences in patients, as their incidence is increasing worldwide.

In-hospital complications associated with pulmonary vein isolation with adjunctive lesions: the NCDR AFib Ablation Registry

AIMS

No prior study has been adequately powered to evaluate real-world safety outcomes in those receiving adjunctive ablation lesions beyond pulmonary vein isolation (PVI). We sought to evaluate characteristics and in-hospital complications among patients undergoing PVI with and without adjunctive lesions.

METHODS AND RESULTS

Patients in the National Cardiovascular Data Registry AFib Ablation Registry undergoing first-time atrial fibrillation (AF) ablation between 2016 and 2020 were identified and stratified into paroxysmal (PAF) and persistent AF, and separated into PVI only, PVI + cavotricuspid isthmus (CTI) ablation, and PVI + adjunctive (superior vena cava isolation, coronary sinus, vein of Marshall, atypical atrial flutter lines, other). Adjusted odds of adverse events were calculated using multivariable logistic regression. A total of 50 937 patients [PAF: 30 551 (60%), persistent AF: 20 386 (40%)] were included. Among those with PAF, there were no differences in the adjusted odds of complications between PVI + CTI or PVI + adjunctive when compared with PVI only. Among persistent AF, PVI + adjunctive was associated with a higher risk of any complication [3.0 vs. 4.5%, odds ratio (OR) 1.30, 95% confidence interval (CI) 1.07-1.58] and major complication (0.8 vs. 1.4%, OR 1.56, 95% CI 1.10-2.21), while no differences were observed in PVI + CTI compared with PVI only. Overall, there was high heterogeneity in adjunctive lesion type, and those receiving adjunctive lesions had a higher comorbidity burden.

CONCLUSION

Additional CTI ablation was common without an increased risk of complications. Adjunctive lesions other than CTI are commonly performed in those with more comorbidities and were associated with an increased risk of complications in persistent AF, although the current analysis is limited by high heterogeneity in adjunctive lesion set type.

Economic and Health Value of Delaying Atrial Fibrillation Progression Using Radiofrequency Catheter Ablation

BACKGROUND

Radiofrequency catheter ablation (RFCA) is an established treatment for atrial fibrillation (AF) refractory to antiarrhythmic drugs. The economic value of RFCA in delaying disease progression has not been quantified.

METHODS

An individual-level, state-transition health economic model estimated the impact of delayed AF progression using RFCA versus antiarrhythmic drug treatment for a hypothetical sample of patients with paroxysmal AF. The model incorporated the lifetime risk of progression from paroxysmal AF to persistent AF, informed by data from the ATTEST (Atrial Fibrillation Progression Trial). The incremental effect of RFCA on disease progression was modeled over a 5-year duration. Annual crossover rates were also included for patients in the antiarrhythmic drug group to mirror clinical practice. Estimates of discounted costs and quality-adjusted life years asssociated with health care utilization, clinical outcomes, and complications were projected over patients' lifetimes.

RESULTS

From the payer's perspective, RFCA was superior to antiarrhythmic drug treatment with an estimated mean net monetary benefit per patient of $8516 ($148-$16 681), driven by reduced health care utilization, cost, and improved quality-adjusted life years. RFCA reduced mean (95% CI) per-patient costs by $73 (-$2700 to $2200), increased mean quality-adjusted life years by 0.084 (0.0-0.17) and decreased the mean number of cardiovascular-related health care encounters by 24%.

CONCLUSIONS

RFCA is a dominant (less costly and more effective) treatment strategy for patients with AF, especially those with early AF for whom RFCA could delay progression to advanced AF. Increased utilization of RFCA-particularly among patients earlier in their disease progression-may provide clinical and economic benefits.

Prognostic benefit of catheter ablation of atrial fibrillation in heart failure: An updated meta-analysis of randomized controlled trials

Background

The prognostic role of catheter ablation of atrial fibrillation (AF) in patients with heart failure (HF) remains uncertain, with guideline recommendations largely based on a single trial. We conducted a meta-analysis of randomized controlled trials (RCTs) assessing the prognostic impact of AF ablation in patients with HF.

Methods

Electronic databases were searched for RCTs comparing 'AF ablation' versus 'other care' (medical therapy and/or atrioventricular node ablation with pacing) in patients with HF. Primary endpoints were ≥1-year mortality, HF hospitalization and change in left ventricular ejection fraction (LVEF). Meta-analyses were performed using random-effects modelling.

Results

Nine RCTs (n = 1462) met inclusion criteria. Compared to 'other care', AF ablation significantly reduced ≥1-year mortality (relative risk [RR] 0.65; 95% confidence intervals [CI], 0.49-0.87) and HF hospitalization (RR 0.64; 95% CI, 0.51-0.81). AF ablation demonstrated significantly greater improvement in LVEF (mean difference [MD] 5.4; 95% CI, 4.4-6.4), 6-min walk test distance (MD 21.5 meters; 95% CI, 4.6-38.4) and quality of life as measured by Minnesota Living with Heart Failure Questionnaire score (MD 7.2; 95% CI, 2.8-11.7). Meta-regression analyses showed the beneficial impact of AF ablation on LVEF was significantly blunted by higher prevalence of ischaemic cardiomyopathy.

Conclusions

Our meta-analysis demonstrates AF ablation is superior to 'other care' in improving mortality, HF hospitalization, LVEF and quality of life in patients with HF. However, the highly selected study populations in included RCTs and effect modification mediated by etiology of HF suggests these benefits do not uniformly apply across the HF population.

Development and Validation of a Novel Prognostic Tool to Predict Recurrence of Paroxysmal Atrial Fibrillation after the First-Time Catheter Ablation: A Retrospective Cohort Study

There is no gold standard to tell frustrating outcomes after the catheter ablation of paroxysmal atrial fibrillation (PAF). The study aims to construct a prognostic tool. We retrospectively analyzed 315 patients with PAF who underwent first-time ablation at the Second Xiangya Hospital of Central South University. The endpoint was identified as any documented relapse of atrial tachyarrhythmia lasting longer than 30 s after the three-month blanking period. Univariate Cox regression analyzed eleven preablation parameters, followed by two supervised machine learning algorithms and stepwise regression to construct a nomogram internally validated. Five factors related to ablation failure were as follows: female sex, left atrial appendage emptying flow velocity ≤31 cm/s, estimated glomerular filtration rate <65.8 mL/(min·1.73 m²), P wave duration in lead aVF ≥ 120 ms, and that in lead V1 ≥ 100 ms, which constructed a nomogram. It was correlated with the CHA₂DS₂-VASc score but outperformed the latter evidently in discrimination and clinical utility, not to mention its robust performances in goodness-of-fit and calibration. In addition, the nomogram-based risk stratification could effectively separate ablation outcomes. Patients at risk of relapse after PAF ablation can be recognized at baseline using the proposed five-factor nomogram.

Oral Class I and III antiarrhythmic drugs for maintaining sinus rhythm after catheter ablation of atrial fibrillation

BACKGROUND

Recurrence of atrial tachyarrhythmias (ATa) following catheter ablation for atrial fibrillation (AF) is a common problem. Antiarrhythmic drugs have been used shortly after ablation in an attempt to maintain sinus rhythm, particularly Class I and III agents. However, it still needs to be established if the use of Class I or III antiarrhythmic medications, or both, reduce the risk of recurrence of ATa.

OBJECTIVES

To assess the effects of oral Class I and III antiarrhythmic drugs versus control (standard medical therapy without Class I or III antiarrhythmics, or placebo) for maintaining sinus rhythm in people undergoing catheter ablation for AF.

SEARCH METHODS

We systematically searched CENTRAL, MEDLINE, Embase, Web of Science Core Collection, and two clinical trial registers without restrictions on language or date to 5 August 2022.

SELECTION CRITERIA

We sought published, unpublished, and ongoing parallel-design, randomised controlled trials (RCTs) involving adult participants undergoing ablation for AF, with subsequent comparison of Class I and/or III antiarrhythmic use versus control (standard medical therapy or non-Class I and/or III antiarrhythmic use).

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane and performed meta-analyses with risk ratios (RR) and Peto odds ratios (Peto OR). Our primary outcomes were recurrence of atrial tachyarrhythmias; adverse events: thromboembolic events; adverse events: myocardial infarction; adverse events: new diagnosis of heart failure; and adverse events: requirement for one or more hospitalisations for atrial tachyarrhythmia. Our secondary outcomes were: all-cause mortality; and requirement for one or more repeat ablations. Where possible, we performed comparison analysis by Class I and/or III antiarrhythmic and divided follow-up periods for our primary outcome. We performed comprehensive assessments of risk of bias and certainty of evidence applying the GRADE methodology.

MAIN RESULTS

We included nine RCTs involving a total of 3269 participants. Participants were on average 59.3 years old; 71.0% were male; and 72.9% and 27.4% had paroxysmal and persistent AF, respectively. Class I and/or III antiarrhythmics may reduce recurrence of ATa at 0 to 3 months postablation (risk ratio (RR) 0.74, 95% confidence interval (CI) 0.59 to 0.94, 8 trials, 3046 participants, low-certainty evidence) and likely reduce recurrence at > 3 to 6 months, our a priori primary time point (RR 0.85, 95% CI 0.78 to 0.93, 5 trials, 2591 participants, moderate-certainty evidence). Beyond six months the evidence is very uncertain, and the benefit of antiarrhythmics may not persist (RR 1.14, 95% CI 0.84 to 1.55, 4 trials, 2244 participants, very low-certainty evidence). The evidence suggests that Class I and/or III antiarrhythmics may not increase the risk of thromboembolic events, myocardial infarction, all-cause mortality, or requirement for repeat ablation, at 0 to 3, > 3 to 6, and > 6 months (where data were available; low- to very low-certainty evidence). The use of Class I and/or III antiarrhythmics postablation likely reduces hospitalisations for ATa by approximately 57% at 0 to 3 months (RR 0.43, 95% CI 0.28 to 0.64, moderate-certainty evidence). No data were available beyond three months. No data were available on new diagnoses of heart failure. Fewer data were available for Class I and III antiarrhythmics individually. Based on only one and two trials (n = 125 to 309), Class I antiarrhythmics may have little effect on recurrence of ATa at 0 to 3, > 3 to 6, and > 6 months (RR 0.88, 95% CI 0.64 to 1.20, 2 trials, 309 participants; RR 0.54, 95% CI 0.25 to 1.19, 1 trial, 125 participants; RR 0.87, 95% CI 0.57 to 1.32, 1 trial, 125 participants; low-certainty evidence throughout); requirement for hospitalisation for ATa at 0 to 3 months (low-certainty evidence); or requirement for repeat ablation at 0 to 3 months (low-certainty evidence). No data were available for thromboembolic events, myocardial infarction, new diagnosis of heart failure, or all-cause mortality at any time points, or hospitalisation or repeat ablation beyond three months. Class III antiarrhythmics may have little effect on recurrence of ATa at up to 3 months and at > 3 to 6 months (RR 0.76, 95% CI 0.50 to 1.16, 4 trials, 599 participants, low-certainty evidence; RR 0.82, 95% CI 0.62 to 1.09, 2 trials, 318 participants, low-certainty evidence), and beyond 6 months one trial reported a possible increase in recurrence of ATa (RR 1.95, 95% CI 1.29 to 2.94, 1 trial, 112 participants, low-certainty evidence). Class III antiarrhythmics likely reduce hospitalisations for ATa at 0 to 3 months (RR 0.40, 95% CI 0.26 to 0.63, moderate-certainty evidence), and may have little effect on all-cause mortality (low- to very low-certainty evidence). The effect of Class III antiarrhythmics on thromboembolic events and requirement for repeat ablation was uncertain (very low-certainty evidence for both outcomes). No data were available for myocardial infarction or new diagnosis of heart failure at any time point, outcomes other than recurrence beyond 6 months, or for hospitalisation and repeat ablation > 3 to 6 months. We assessed the majority of included trials as at low or unclear risk of bias. One trial reported an error in the randomisation process, raising the potential risk of selection bias; most of the included trials were non-blinded; and two trials were at high risk of attrition bias.

AUTHORS' CONCLUSIONS

We found evidence to suggest that the use of Class I and/or III antiarrhythmics up to 3 months after ablation is associated with a reduced recurrence of ATa 0 to 6 months after ablation, which may not persist beyond 6 months, and an immediate reduction in hospitalisation for ATa 0 to 3 months after ablation. The evidence suggests there is no difference in rates of all-cause mortality, thromboembolic events, or myocardial infarction between Class I and/or III antiarrhythmics versus control.

Predictors of Maintenance of Sinus Rhythm After Radiofrequency Catheter Ablation for Long-Standing Persistent Atrial Fibrillation

Little has been reported on the predictors of maintenance of sinus rhythm (SR) after radiofrequency catheter ablation (RFCA) for long-standing persistent atrial fibrillation (AF). We enrolled 151 patients with long-standing persistent AF (defined as AF lasting more than 12 months) who underwent an initial RFCA between October 2014 and December 2020 in our hospital. These patients were categorized into 2 groups on the basis of the absence and presence of the late recurrence (LR, defined as a recurrence of atrial tachyarrhythmia between 3 and 12 months after RFCA): SR group and LR group. The SR group comprised 92 patients (61%). In the univariate analysis, there were significant differences in gender and preprocedural average heart rate (HR) between the 2 groups (p = 0.042 and p = 0.042, respectively). A receiver operating characteristics analysis revealed that a cut-off value of preprocedural average HR to predict the maintenance of SR was 85 beats/min (sensitivity: 37%, specificity: 85%, area under curve: 0.58). A multivariate analysis showed that preprocedural average HR ≥85 beats/min was independently associated with the maintenance of SR after RFCA (odds ratio 3.30, 95% confidence interval 1.47 to 8.04, p = 0.003). In conclusion, a relatively high preprocedural average HR might be a prognostic factor of maintenance of SR after RFCA for long-standing persistent AF.

Initial Findings From the National Cardiovascular Data Registry of Atrial Fibrillation Ablation Procedures

BACKGROUND

The National Cardiovascular Data Registry (NCDR) AFib Ablation Registry was created to assess real-world prevalence, demographic characteristics, procedural management, and outcomes of patients undergoing atrial fibrillation (AF) ablation procedures.

OBJECTIVES

The goal of this study was to characterize the patient, hospital, and physician characteristics and in-hospital outcomes related to AF ablation in the first 5 years of the registry.

METHODS

This paper describes the AFib Ablation Registry structure and governance, outcome assessment processes, data quality, and data collection processes. The characteristics of the patient population, hospitals, and in-hospital outcomes are also described.

RESULTS

A total of 76,219 patients were included in the registry between January 2016 and December 2020 (mean age 65.5 ± 10.3 years, 65.2% male, 55.8% paroxysmal AF, mean CHA₂DS₂-VASc score 2.7 ± 1.6) treated by 708 physicians in 162 hospitals. Successful isolation of all pulmonary veins was achieved in 92.4% of patients. The prevalence of any complication during procedural admission was 2.50% and major complication was 0.9%, including significant bradycardia in 0.47%, heart failure in 0.47%, and pericardial effusion requiring intervention in 0.44%. Hospitalization >1 day occurred in 11.8% of patients, and in-hospital death was rare (n = 41 [0.05%]).

CONCLUSIONS

The NCDR AFib Ablation Registry is the largest multicenter, prospective cohort study of patients undergoing catheter ablation worldwide. Results in the first 5 years showed that successful pulmonary vein isolation is achieved in the majority of patients, with a low rate of complications. Future studies from the registry will assess practice trends, evaluate treatment patterns associated with different patient outcomes, and support development of evidence-based guidelines.

Early rhythm control vs. rate control in atrial fibrillation: A systematic review and meta-analysis

Objective

It has long been debated whether rhythm control vs. rate control strategies have differing effects on mortality and morbidity for atrial fibrillation (AF). Recently, several randomized controlled studies (RCTs) and observational trials described that an early rhythm management method was linked to a lower likelihood of negative clinical outcomes in individuals with AF. We wanted to see if an early rhythm management method may help patients with AF.

Methods

We performed a systematic search to retrieve studies assessing the outcomes of early rhythm control vs. rate control in AF by using PubMed, Web of Science, Cochrane Library, and Embase published between 01/01/2000 and 15/04/2022.

Results

Finally, two RCTs, one retrospective analysis of RCTs, and four observational studies were identified. Compared with rate control, early rhythm control has been linked to lower all-cause mortality. [risk ratio (RR), 0.76; 95% CI 0.69-0.83; P < 0.00001; I 2 = 77%]. The early rhythm control group was also associated with a lower risk of cardiovascular mortality (RR, 0.68; 95% CI 0.63-0.74; P < 0.00001; I 2 = 33), stroke (RR, 0.77; 95% CI 0.67-0.87; P < 0.001; I 2 = 64), and heart failure hospitalization (RR, 0.74; 95% CI 0.59-0.93; P = 0.0009; I 2 = 93%). We found no significant difference in nights spent in hospital per year, acute coronary syndrome, major bleeding, and cardiac arrest/ventricular arrhythmia between the groups.

Conclusion

In this meta-analysis, early rhythm therapy was linked to a lower risk of all-cause mortality, cardiovascular mortality, stroke, and heart failure hospitalization compared with the rate control group.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022333592.

Pulmonary vein isolation alone or in combination with substrate modulation after electrical cardioversion failure in patients with persistent atrial fibrillation: The PACIFIC trial: Study design

INTRODUCTION

Pulmonary vein isolation (PVI) is effective at treating 50% of unselected patients with persistent atrial fibrillation (AF). Alternatively, PVI combined with a new ablation strategy entitled the Marshall-PLAN ensures a 78% 1-year sinus rhythm (SR) maintenance rate in the same population. However, a substantial subset of patients could undergo the Marshall-PLAN unnecessarily. It is therefore essential to identify those patients who can be treated with PVI alone versus those who may truly benefit from the Marshall-PLAN before ablation is performed. In this context, we hypothesized that electrical cardioversion (EC) could help to select the most appropriate strategy for each patient.

METHODS

In this multicentre, prospective, randomized study, patients with AF recurrence within 4 weeks after EC will be randomized 1:1 to PVI alone or the Marshall-PLAN. Conversely, patients in whom SR is maintained for ≥4 weeks after EC will be treated with PVI only and included in a prospective registry. The primary endpoint will be the 1-year SR maintenance rate after a single ablation procedure.

RESULTS AND CONCLUSION

The Marshall-PLAN might be necessary in patients with an advanced degree of persistent AF (i.e., where SR is not maintained for ≥4 uninterrupted weeks after EC). Conversely, in patients with mild or moderate persistent AF (i.e., where SR is maintained for ≥4 weeks after EC), PVI alone might be a sufficient ablation strategy. The PACIFIC trial is the first study designed to assess whether rhythm monitoring after EC could help to identify patients who should undergo adjunctive ablation strategies beyond PVI.

Ablation of atrial fibrillation beyond pulmonary vein isolation: Do additional ablation lesions impact left atrial function?

INTRODUCTION

Electrical isolation of pulmonary veins (PVI) is a cornerstone for atrial fibrillation (AF) ablation. The overall effect of AF ablation, and especially lesions beyond PVI, on left atrial (LA) function is currently poorly understood. Our aim was to determine if LA function is different in patients after extensive LA ablation compared to PVI only. We performed non-inferiority analysis of LA function after PVI with additional nonpulmonary vein ablation lesions in LA (PVI+) and PVI alone.

METHODS

We studied 68 patients consecutive patients who underwent AF ablation and who had complete transthoracic echocardiogram (TTE) within 12 months before AF ablation and 1-12 months after the procedure. Patients were stratified into two groups: PVI only and PVI+. Primary outcome was change in LA reservoir strain (LASr). Noninferiority margin was defined at 6%.

RESULTS

The PVI only group had a higher proportion of patients with paroxysmal AF (70% vs. 30%). The PVI+ group was observed to have a slightly higher increase in LASr compared to PVI alone (5.0% vs. 4.3%, p < .01 for noninferiority). LASr noninferiority was confirmed when adjusted for age, sex, coronary artery disease, hyperlipidemia, and AF type, rhythm at preprocedure TTE in a multivariable linear regression model, 90% CI (-5.46 to 2.04), p < .01.

CONCLUSION

LA functional improvement evaluated by LASr was noninferior after PVI with additional LA ablation lesions compared to PVI alone. These findings were confirmed when adjusted for confounding clinical variables, suggesting that more extensive ablation does not negatively affect LA function.

Ablation therapies for paroxysmal atrial fibrillation: A systematic review and patient-level network meta-analysis

Introduction: Despite promising trials, catheter ablation is still regarded as an adjunct to antiarrhythmic drugs (AADs) in the treatment of paroxysmal atrial fibrillation (PAF). This study aimed to compare the effectiveness of various ablation therapies and AAD. Method: Randomised controlled trials or propensity score-matched studies comparing atrial tachyarrhythmia recurrence among any combination of ablation modalities or AAD were retrieved. Kaplan-Meier curves and risk tables for this outcome were graphically reconstructed to extract patient-level data. Frequentist network meta-analysis (NMA) using derived hazard ratios (HRs), as well as 2 restricted mean survival time (RMST) NMAs, were conducted. Treatment strategies were ranked using P-scores. Results: Across 24 studies comparing 6 ablation therapies (5,132 patients), Frequentist NMA-derived HRs of atrial fibrillation recurrence compared to AAD were 0.35 (95% confidence interval [CI]=0.25–0.48) for cryoballoon ablation (CBA), 0.34 (95% CI=0.25–0.47) for radiofrequency ablation (RFA), 0.14 (95% CI=0.07–0.30) for combined CBA and RFA, 0.20 (95% CI=0.10–0.41) for hot-balloon ablation, 0.43 (95% CI=0.15–1.26) for laser-balloon ablation (LBA), and 0.33 (95% CI=0.18–0.62) for pulmonary vein ablation catheter. RMST-based NMAs similarly showed significant benefit of all ablation therapies over AAD. The combination of CBA + RFA showed promising long-term superiority over CBA and RFA, while LBA showed favourable short-term efficacy. Conclusion: The advantage of ablation therapies over AAD in preventing atrial tachyarrhythmia recurrence suggests that ablation should be considered as the first-line treatment for PAF in patients fit for the procedure. The promising nature of several specific therapies warrants further trials to elicit their long-term efficacy and perform a cost-benefit analysis. Keywords: Atrial fibrillation, catheter ablation, network meta-analysis

Cost-effectiveness of rhythm control strategy: Ablation versus antiarrhythmic drugs for treating atrial fibrillation in Korea based on real-world data

Background

Ablation-based treatment has emerged as an alternative rhythm control strategy for symptomatic atrial fibrillation (AF). Recent studies have demonstrated the cost-effectiveness of ablation compared with medical therapy in various circumstances. We assessed the economic comparison between ablation and medical therapy based on a nationwide real-world population.

Methods and findings

For 192,345 patients with new-onset AF (age ≥ 18 years) identified between August 2015 and July 2018 from the Korean Health Insurance Review and Assessment Service (HIRA) database, medical resource use data were collected to compare AF patients that underwent ablation (N = 2,131) and those administered antiarrhythmic drugs (N = 8,048). Subsequently, a Markov chain Monte Carlo model was built. The patients had at least one risk factor for stroke, and the base-case used a 20-year time horizon, discounting at 4.5% annually. Transition probabilities and costs were estimated using the present data, and utilities were derived from literature review. The costs were converted to US $ (2019). Sensitivity analyses were performed using probabilistic and deterministic methods. The net costs and quality-adjusted life years (QALY) for antiarrhythmic drugs and ablation treatments were $37,421 and 8.8 QALYs and $39,820 and 9.3 QALYs, respectively. Compared with antiarrhythmic drugs, incremental cost-effectiveness ratio of ablation was $4,739/QALY, which is lower than the willingness-to-pay (WTP) threshold of $32,000/QALY.

Conclusion

In symptomatic AF patients with a stroke risk under the age of 75 years, ablation-based rhythm control is potentially a more economically attractive option compared with antiarrhythmic drug-based rhythm control in Korea.

Jet Ventilation Reduces Coronary Sinus Movement in Patients Undergoing Atrial Fibrillation Ablation: An Observational Crossover Study

BACKGROUND

One of the reasons that high-frequency jet ventilation (HFJV) is used is due to the near immobility of thoracic structures. However, no study has quantified the movements of cardiac structures during HFJV compared with normal mechanical ventilation.

METHODS

After ethical approval and written informed consent, we included 21 patients scheduled for atrial fibrillation ablation in this prospective crossover study. Each patient was ventilated with both normal mechanical ventilation and HFJV. During each ventilation mode, displacements of the cardiac structure were measured by the EnSite Precision mapping system using a catheter placed in the coronary sinus.

RESULTS

The median [Q1-Q4] displacement was 2.0 [0.6-2.8] mm during HFJV and 10.5 [9.3-13.0] mm during conventional ventilation (p < 0.000001).

CONCLUSION

This study quantifies the minimal movement of cardiac structures during HFJV compared to standard mechanical ventilation.

Some Thoughts on the Use of Predictive Probability in Clinical Trials

In this short note, we express our viewpoint regarding declaring study success based on Bayesian predictive probability of study success.

Human in vitro assay for irreversible electroporation cardiac ablation

Introduction: Pulsed electric field (PEF) cardiac ablation has been recently proposed as a technique to treat drug resistant atrial fibrillation by inducing cell death through irreversible electroporation (IRE). Improper PEF dosing can result in thermal damage or reversible electroporation. The lack of comprehensive and systematic studies to select PEF parameters for safe and effective IRE cardiac treatments hinders device development and regulatory decision-making. Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have been proposed as an alternative to animal models in the evaluation of cardiac electrophysiology safety. Methods: We developed a novel high-throughput in vitro assay to quantify the electric field threshold (EFT) for electroporation (acute effect) and cell death (long-term effect) in hiPSC-CMs. Monolayers of hiPSC-CMs were cultured in high-throughput format and exposed to clinically relevant biphasic PEF treatments. Electroporation and cell death areas were identified using fluorescent probes and confocal microscopy; electroporation and cell death EFTs were quantified by comparison of fluorescent images with electric field numerical simulations. Results: Study results confirmed that PEF induces electroporation and cell death in hiPSC-CMs, dependent on the number of pulses and the amplitude, duration, and repetition frequency. In addition, PEF-induced temperature increase, absorbed dose, and total treatment time for each PEF parameter combination are reported. Discussion: Upon verification of the translatability of the in vitro results presented here to in vivo models, this novel hiPSC-CM-based assay could be used as an alternative to animal or human studies and can assist in early nonclinical device development, as well as inform regulatory decision-making for cardiac ablation medical devices.

Ablation versus anti-arrhythmic therapy for reducing all hospital episodes from recurrent atrial fibrillation: a prospective, randomized, multi-centre, open label trial

AIMS

There is rising healthcare utilization related to the increasing incidence and prevalence of atrial fibrillation (AF) worldwide. Simplifying therapy and reducing hospital episodes would be a valuable development. The efficacy of a streamlined AF ablation approach was compared to drug therapy and a conventional catheter ablation technique for symptom control in paroxysmal AF.

METHODS AND RESULTS

We recruited 321 patients with symptomatic paroxysmal AF to a prospective randomized, multi-centre, open label trial at 13 UK hospitals. Patients were randomized 1:1:1 to cryo-balloon ablation without electrical mapping with patients discharged same day [Ablation Versus Anti-arrhythmic Therapy for Reducing All Hospital Episodes from Recurrent (AVATAR) protocol]; optimization of drug therapy; or cryo-balloon ablation with confirmation of pulmonary vein isolation and overnight hospitalization. The primary endpoint was time to any hospital episode related to treatment for atrial arrhythmia. Secondary endpoints included complications of treatment and quality-of-life measures. The hazard ratio (HR) for a primary endpoint event occurring when comparing AVATAR protocol arm to drug therapy was 0.156 (95% CI, 0.097-0.250; P < 0.0001 by Cox regression). Twenty-three patients (21%) recorded an endpoint event in the AVATAR arm compared to 76 patients (74%) within the drug therapy arm. Comparing AVATAR and conventional ablation arms resulted in a non-significant HR of 1.173 (95% CI, 0.639-2.154; P = 0.61 by Cox regression) with 23 patients (21%) and 19 patients (18%), respectively, recording primary endpoint events (P = 0.61 by log-rank test).

CONCLUSION

The AVATAR protocol was superior to drug therapy for avoiding hospital episodes related to AF treatment, but conventional cryoablation was not superior to the AVATAR protocol. This could have wide-ranging implications on how demand for AF symptom control is met.

TRIAL REGISTRATION

Clinical Trials Registration: NCT02459574.

Early Atrial Tachyarrhythmia Recurrence Predicts Late Atrial Tachyarrhythmia Recurrence After the Cryo-Maze Procedure - An Observational Study

BACKGROUND

It is unknown whether early atrial tachyarrhythmia (ATA) recurrence occurring within 3 months after the Maze procedure predicts late ATA recurrence.

METHODS AND RESULTS

This study involved 610 patients who underwent the modified Cryo-Maze procedure in conjunction with other cardiac surgery. The primary outcomes were late ATA recurrence, defined as occurring ≥3 months after surgery. The effects of early ATA recurrence on late ATA recurrence were analyzed using a Cox proportional hazards model. The following 11 covariates were considered explanatory variables: early ATA recurrence, age, sex, body surface area, preoperative duration of atrial fibrillation, preoperative left atrial diameter, and concomitant surgery (mitral valve replacement, mitral valve repair, aortic valve replacement, tricuspid annuloplasty, and left atrial appendage closure). Statistical analyses were performed with a 2-sided 5% significance level. Early ATA recurrence occurred in 174 patients (28.5%). Late ATA recurrence occurred in 167 patients (27.5%), with 595 events identified in these patients. The Cox proportional hazards model showed that early ATA recurrence was an independent predictor of late ATA recurrence (hazard ratio, 4.14; 95% confidence interval, 3.00-5.70; P<0.001).

CONCLUSIONS

Early ATA recurrence was an independent predictor of late ATA recurrence among patients undergoing the modified Cryo-Maze procedure. The blanking period might not be applied to patients undergoing the modified Cryo-Maze procedure.