Unexpectedly High Incidence of Stroke and Left Atrial Appendage Thrombus Formation After Electrical Isolation of the Left Atrial Appendage for the Treatment of Atrial Tachyarrhythmias

Catheter Ablation of Atrial Fibrillation: Technique and Future Perspectives

Atrial fibrillation is the most common sustained cardiac arrhythmia with a significant impact on quality of life in terms of symptoms and reduction of functional status. Also, it is associated with an increased risk of mortality, stroke, and peripheral embolism. Catheter ablation for atrial fibrillation has become a well-established treatment, improving arrhythmia outcomes without increasing the risk of serious adverse events compared to antiarrhythmic drug therapy. The field has undergone significant advancements in recent years, yet pulmonary vein isolation continues to be the cornerstone of any atrial fibrillation ablation procedure. The purpose of this review is to provide an overview of the current techniques, emerging technologies, and future directions.

Electrical isolation of the left atrial appendage in East Asian patients with atrial fibrillation

Background

The left atrial appendage (LAA) is a source of non-pulmonary vein triggers in patients with atrial fibrillation (AF). Electrical isolation of the LAA (EILAA) improves rhythm outcome with an inherent risk of embolism unless lifelong anticoagulation is continued. However, evidence of the efficacy and safety of EILAA in the East Asian population remains lacking.

Objective

The purpose of this study was to evaluate the efficacy and safety in East Asian patients who underwent EILAA.

Methods

Using the data from a single center, we identified patients who underwent EILAA for AF between January 2009 and August 2023. Clinical and procedural data were analyzed.

Results

We included a total of 41 patients who underwent EILAA. EILAA was unsuccessful in 2 patients. The median duration of AF was 5.0 years (interquartile range 4.0-10.0 years). Twenty-five patients (65.8%) underwent more than 1 previous ablation for AF before the index procedure. The mean CHA2DS2-VASc score was 2.8 ± 1.6. The mean left atrial dimension was 50.6 ± 8.7 mm. The 1-year recurrence rate of atrial arrhythmia after EILAA was 42.0% (21 patients during follow-up). Six patients (14.6%) underwent redo ablation, and 5 of them had durable isolation of the LAA. One patient had cardiac tamponade, which was drained with pericardiocentesis. All patients had taken lifelong anticoagulation, and 3 of them had stroke or systemic embolism during the follow-up period.

Conclusion

EILAA could be a safe and effective strategy for patients with long-standing AF with a history of failed ablation, especially with a high CHA2DS2-VASc score. Lifelong anticoagulation is mandatory for patients undergoing EILAA.

Atypical Atrial Flutter: Electrophysiological Characterization and Effective Catheter Ablation

Atrial flutter (AFL), defined as macro-re-entrant atrial tachycardia, is associated with debilitating symptoms, stroke, heart failure, and increased mortality. AFL is classified into typical, or cavotricuspid isthmus (CTI)-dependent, and atypical, or non-CTI-dependent. Atypical AFL is a heterogenous group of re-entrant atrial tachycardias that most commonly occur in patients with prior heart surgery or catheter ablation. The ECG pattern is poorly predictive of circuit anatomy but may still provide mechanistic insight. AFL is difficult to manage medically and catheter ablation is the preferred treatment for most patients. Recent progress in technology and clinical electrophysiology has led to detailed characterization of re-entry circuits and effective ablation strategies. Combined activation and entrainment mapping are key to identifying the re-entry circuit. The presence of a slow-conducting isthmus, localized re-entry, dual-loop re-entry or bystander loops may lead to misleading activation maps but can be identified by electrogram examination and entrainment mapping. In the occasional patient without inducible AFL, substrate mapping in sinus rhythm may be a viable strategy. Long-term ablation success requires the creation of a transmural continuous lesion across a critical component of the re-entry circuit. Procedural endpoints include bidirectional conduction block across linear lesions and non-inducibility of atrial tachycardia. The present review discusses the epidemiology, mechanisms, ECG characteristics, electrophysiological characterization, and catheter ablation of atypical AFL.

Late Onset of Left Atrial Appendage Thrombus Under Oral Anticoagulation in a Patient with a History of Left Atrial Appendage Isolation Using Cryoballoon

Empirical left atrial appendage isolation (eLAAi) using a cryoballoon reduces atrial tachyarrhythmia recurrences in persistent atrial fibrillation. Nonetheless, the most significant concern associated with this procedure is the risk of thromboembolic events, particularly without consistent oral anticoagulant (OAC) use. This case highlights a late thrombus formation post-eLAAi despite proper OAC adherence, raising questions about OAC's effectiveness in such scenarios. The case suggests considering percutaneous left atrial appendage closure after eLAAi, even in patients with thrombus and ongoing OAC therapy.

Ablation Strategies for Repeat Procedures in Atrial Fibrillation Recurrences Despite Durable Pulmonary Vein Isolation: The Prospective Randomized ASTRO AF Multicenter Trial

BACKGROUND

Ablation strategies for patients with symptomatic atrial fibrillation and isolated pulmonary veins vary and their effects on arrhythmia recurrence remain unclear. A prospective randomized German multicenter trial sought to compare 2 ablation strategies in this patient cohort.

METHODS

Patients with atrial fibrillation despite durable pulmonary vein isolation were randomly assigned at 7 centers to undergo low-voltage area ablation using 3-dimensional mapping and irrigated radiofrequency current ablation (group A) or empirical left atrial appendage isolation (LAAI) using the cryoballoon followed by staged interventional left atrial appendage closure (group B). The primary end point was freedom from atrial tachyarrhythmias between 91 and 365 days after index ablation. The study was powered for superiority of LAAI compared with low-voltage area.

RESULTS

Patients (40% women; mean age, 68.8±8 years) with paroxysmal (32%) or persistent atrial fibrillation (68%) were randomized to undergo low-voltage area ablation (n=79) or cryoballoon-guided LAAI (n=82). After a planned interim analysis, enrollment was halted for futility on January 10, 2023. In the LAAI group, 77 of 82 left atrial appendages were successfully isolated with subsequent left atrial appendage closure in 57 patients. Procedure-related complications occurred in 4 (5%) and 11 (13.5%) patients in group A and B, respectively (P=0.10). The median follow-up was 367 days (interquartile range, 359-378). The Kaplan-Meier point estimate for freedom from atrial tachyarrhythmias was 51.7% (CI, 40.9%-65.4%) for group A and 55.5% (CI, 44.4%-69.2%; P=0.8069) for group B.

CONCLUSIONS

The current study did not detect superiority of cryoballoon-guided LAAI over low-voltage area ablation in patients with atrial fibrillation despite durable PVI.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04056390.

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.

Are drivers recurring or ephemeral? observations from serial mapping of persistent atrial fibrillation

AIMS

Rotational re-entries and ectopic foci, or 'drivers', are proposed mechanisms for persistent atrial fibrillation (persAF), but driver-based interventions have had mixed success in clinical trials. Selective targeting of drivers with multi-month stability may improve these interventions, but no prior work has investigated whether drivers can be stable on such a long timescale.

OBJECTIVE

We hypothesized that drivers could recur even several months after initial observation.

METHODS AND RESULTS

We performed serial electrophysiology studies on paced canines (n = 18, 27-35 kg) at 1-, 3-, and 6 months post-initiation of continual persAF. Using a high-density 64-electrode catheter, we captured endocardial electrograms in the left atrium (LA) and right atrium (RA) to determine the presence of drivers at each major anatomical site. We defined drivers that were repeatedly observed across consecutive studies to be recurrent. The mean probability that any driver would recur was 66% (LA: 73%, RA: 41%). We also found evidence of 'multi-recurring' drivers, i.e. those seen in all three studies. Multi-recurring drivers constituted 53% of initially observed drivers with at least one found in 92% of animals, and we found more multi-recurring drivers per animal than predicted by random chance (2.6 ± 1.5 vs. 1.2 ± 1.1, P < 0.001). Driver sites showed more enhancement than non-drivers during late gadolinium enhancement-magnetic resonance imaging (P = 0.04), but we observed no relationship between enhancement and driver recurrence type.

CONCLUSION

We observed recurring drivers over a 6-month period at fixed locations, confirming our hypothesis. We also found drivers to be associated with fibrosis, implying a structural basis.

Left atrial appendage anatomy: clinical implications for cardiac procedures

The Left Atrial Appendage (LAA) is the most common source of thrombi during atrial fibrillation (AF) leading to stroke. With the increasing prevalence of AF and the growing number of patients requiring LAA involved interventions like exclusion and ablation, understanding LAA's anatomical intricacies becomes paramount importance. This study aims to provide anatomical data regarding LAA in relation to these procedures. Total 50 formalin-fixed cadaveric hearts were examined and various morphological and morphometric parameters were noted. The Cauliflower shape LAA (36%) was most common followed by Chicken Wing (34%), Cactus (18%), and Windsock (12%) shapes. The LAA orifice had greater horizontal diameter compared to the vertical diameter and was oval in shape in 64% cases. Diverticular structures called divots/ pits were present surrounding the LAA orifice in 36% cases with high variation in number, size, and distance from orifice. They were most commonly present towards the septal side and posterior wall side around the LAA orifice. The circumflex artery was the closest structure to LAA orifice with less than 5 mm distance in 76% cases. Other structures present close to the LAA were the Left Superior Pulmonary Vein and Mitral Valve. According to shape, the Non-Chicken Wing morphology of the LAA was associated with close running left circumflex artery, high OI (Ovality Index) of the orifice, and greater presence of divots. The LAA anatomy is complex with high amount of variability making it difficult to perform successful procedures. Given data can help clinicians in better planning and execution of cardiac interventions involving the LAA.

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.

Ablation Strategies for Persistent Atrial Fibrillation: Beyond the Pulmonary Veins

Despite advances in ablative therapies, outcomes remain less favorable for persistent atrial fibrillation often due to presence of non-pulmonary vein triggers and abnormal atrial substrates. This review highlights advances in ablation technologies and notable scientific literature on clinical outcomes associated with pursuing adjunctive ablation targets and substrate modification during persistent atrial fibrillation ablation, while also highlighting notable future directions.

Clinical incidence and relevance of incomplete endothelialization in atrial fibrillation patients with Left Atrial Appendage Closure

BACKGROUND

The objective of this study is to investigate the incidence, potential risk factors, and clinical outcomes of incomplete device endothelialization (IDE) in atrial fibrillation (AF) patients undergoing Watchman left atrial appendage closure (LAAC).

METHODS

In this study, 68 AF patients who underwent successful implantation of the Watchman device without peri-device leak (PDL) during follow-up were included. The endothelialization status was assessed using Transesophageal echocardiography (TEE) and LAA computed tomography angiography (CTA) at 6 weeks and 6 months post-implantation. Adverse cerebro-cardiac events were documented at one-year follow-up. Baseline characteristics, including age, device sizes, and clinical indicators, were analyzed as potential predictors for IDE.

RESULTS

IDE was observed in 70.6% and 67.6% of patients at 6 weeks and 6 months after implantation, respectively. Higher levels of high-density lipoprotein cholesterol (HDL-C) [odds ratio (OR): 15.109, 95% confidence interval (CI): 1.637-139.478, p = 0.017 and OR: 11.015, 95% CI: 1.365-88.896, p = 0.024] and lower aspartate aminotransferase (AST) (OR 0.924, 95% CI: 0.865-0.986, p = 0.017 and OR: 0.930, 95% CI: 0.874-0.990, p = 0.023) at baseline were found to be significantly associated with IDE at 6 weeks and 6 months, respectively, although no significant difference in adverse cerebro-cardiac events was noted between incomplete and complete DE groups during 1-year follow-up CONCLUSIONS: IDE is found to be a prevalent occurrence in humans following LAAC. Elevated HDL-C and reduced AST levels are shown to be linked to an increased risk of IDE after LAAC.

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 (HRS), the Asia Pacific HRS, and the Latin American HRS.

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.

Safety and efficacy of the second-generation cryoballoon for left atrial appendage electrical isolation in canines

AIMS

Left atrial appendage electrical isolation (LAAEI) has demonstrated a significant enhancement in the success rate of atrial fibrillation (AF) ablation. Nevertheless, concerns persist about the safety of LAAEI, particularly regarding alterations in left atrial appendage (LAA) flow velocity and the potential risks of thrombus. This study aimed to assess the efficacy and safety of LAAEI, investigating changes in LAA flow velocity in canines.

METHODS AND RESULTS

The study comprised a total of 10 canines. The LAAEI procedure used by a 23 mm cryoballoon of the second generation was conducted at least 180 s. Intracardiac ultrasonography (ICE) was employed to quantify the velocity flow of the LAA both prior to and following LAAEI. Following a 3-month period, subsequent evaluations were performed to assess the LAA velocity flow and the potential reconnection. Histopathological examination was conducted. Left atrial appendage electrical isolation was effectively accomplished in all canines, resulting in a 100% acute success rate (10/10). The flow velocity in the LAA showed a notable reduction during LAAEI as compared with the values before the ablation procedure (53.12 ± 5.89 vs. 42.01 ± 9.22 cm/s, P = 0.007). After the follow-up, reconnection was observed in four canines, leading to a success rate of LAAEI of 60% (6/10). The flow velocity in the LAA was consistently lower (53.12 ± 5.89 vs. 44.33 ± 10.49 cm/s, P = 0.006), and no blood clot development was observed. The histopathological study indicated that there was consistent and complete injury to the LAA, affecting all layers of its wall. The injured tissue was subsequently replaced by fibrous tissue.

CONCLUSION

The feasibility of using cryoballoon ablation for LAAEI was confirmed in canines, leading to a significant reduction of LAA flow velocity after ablation. Some restoration of LAA flow velocity after ablation may be linked to the passive movement of the LAA and potential reconnecting. However, this conclusion is limited to animal study; more clinical data are needed to further illustrate the safety and accessibility of LAAEI in humans.

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 .

Catheter ablation for non-paroxysmal atrial fibrillation. A review

Atrial fibrillation (AF), the most common cardiac arrhythmia is associated with increased morbidity and mortality. The higher mortality is due to the risk of heart failure and cardioembolic events. This in-depth review focuses on the strategies and efficacy of catheter ablation for non-paroxysmal atrial fibrillation. The main medical databases were searched for contemporary studies on catheter ablation for non-paroxysmal AF. Catheter ablation is currently proven to be the most effective treatment for AF and consists of pulmonary vein isolation as the cornerstone plus additional ablations. In terms of SR maintenance, it is less effective in non-paroxysmal AF than in paroxysmal patients. but the clinical benefit in non-paroxysmal patients is substantially higher. Since pulmonary vein isolation is ineffective, a variety of techniques have been developed, e.g. linear ablations, ablation of complex atrial fractionated electrograms, etc. Another paradox consists in the technique of catheter ablation. Despite promising results in early observation studies, further randomized studies have not confirmed the initial enthusiasm. Recently, a new approach, pulsed-field ablation, appears promising. This is an in-depth summary of current technologies and techniques for the ablation of non-paroxysmal AF. We discuss the benefits, risks and implications in the treatment of patients with non-paroxysmal AF.

Hybrid Endo-Epicardial Therapies for Advanced Atrial Fibrillation

Atrial fibrillation (AF) is a growing health problem that increases morbidity and mortality, and in most patients progresses to more advanced diseases over time. Recent research has examined the underlying mechanisms, risk factors, and progression of AF, leading to updated AF disease classification schemes. Although endocardial catheter ablation is effective for early-stage paroxysmal AF, it consistently achieves suboptimal outcomes in patients with advanced AF. Identification of the factors that lead to the increased risk of treatment failure in advanced AF has spurred the development and adoption of hybrid ablation therapies and collaborative heart care teams that result in higher long-term arrhythmia-free survival. Patients with non-paroxysmal AF, atrial remodeling, comorbidities, or AF otherwise deemed difficult to treat may find hybrid treatment to be the most effective option. Future research of hybrid therapies in advanced AF patient populations, including those with dual diagnoses, may provide further evidence establishing the safety and efficacy of hybrid endo-epicardial ablation as a first line treatment.

Cryoballoon ablation of non-PV triggers in persistent atrial fibrillation

Cryoballoon-based catheter ablation has emerged as an efficacious and safe therapeutic intervention for patients with paroxysmal atrial fibrillation (PAF). PAF is primarily associated with the triggers in the pulmonary vein (PV). However, persistent atrial fibrillation (PeAF) is a complex condition that involves changes in the atrial substrate and the presence of non-PV triggers. Therefore, a comprehensive treatment approach is necessary for patients with PeAF. Utilizing a 3D electroanatomical map, the radiofrequency-based ablation technique adeptly identifies and targets the atrial substrate and non-PV triggers. On the other hand, the cryoballoon-based AF ablation was initially designed for PV isolation. However, its single-shot feature makes it a great choice for electrophysiologists looking to address non-PV triggers. It is possible to target the left atrial appendage (LAA), superior vena cava (SVC), left atrial roof, and posterior wall using the apparatus's unique configuration and ablation abilities. This review focuses on the increasing literature regarding cryoballoon-based methods for non-PV trigger ablation. Specifically, it delves into the technical procedures used to isolate the LAA, SVC, and ablate the left atrial roof and posterior wall.

Bachmann's Bundle Modification in Addition to Circumferential Pulmonary Vein Isolation for Atrial Fibrillation: A Novel Ablation Strategy

Background

Bachmann's bundle (BB) is the main pathway of interatrial connection that could be involved in the development of atrial fibrillation (AF). Based on this hypothesis, we raised a novel ablation strategy, BB modification in addition to circumferential pulmonary vein isolation (CPVI-BB) in patients with AF.

Methods

A retrospective cohort of patients with AF who underwent CPVI-BB or CPVI alone from March 2018 to July 2021 was enrolled in our study. Propensity score matching was performed in patients with paroxysmal AF and persistent AF, respectively, to reduce the risk of selection bias between the treatment strategies (CPVI-BB or CPVI alone). The primary endpoint was overall freedom from atrial arrhythmia recurrence through 12 months of follow-up.

Results

Our propensity score-matched cohort included 82 patients with paroxysmal AF (CPVI group: n = 41; CPVI-BB group: n = 41) and 168 patients with persistent AF (CPVI group: n = 84; CPVI-BB group: n = 84). Among patients with persistent AF, one-year freedom from atrial arrhythmia recurrence rate was 83.3% in the CPVI-BB group and 70.2% in the CPVI group (log-rank P = 0.047). Among patients with paroxysmal AF, no significant difference was found in the primary endpoint between two groups (85.4% in the CPVI-BB group vs. 80.5% in the CPVI group; log-rank P = 0.581). In addition, procedure-related complications and recurrence of atrial tachycardia or atrial flutter were similar between the two treatment groups, regardless of the type of AF.

Conclusions

BB modification in addition to CPVI is an effective approach in increasing the maintenance of sinus rhythm in patients with persistent AF, while it does not improve the clinical outcomes of radiofrequency catheter ablation in patients with paroxysmal AF.

Radiofrequency catheter ablation of atrial fibrillation: A review of techniques

Ablation of atrial fibrillation is a key area of current research. A multitude of techniques have been tested, some of which are poorly evidenced and not recommended in routine clinical practice whilst others are more promising. Additionally, a plethora of issues exist when researching ablation techniques, from control arm ablation strategy to the relevance of outcome measures. In this review article, we discuss these issues in the context of the current evidence base.

Role of non-pulmonary vein triggers in persistent atrial fibrillation

Pulmonary vein isolation is an well-established treatment strategy for atrial fibrillation (AF), and it is especially effective for patients with paroxysmal AF. However, the success rate is limited for patients with persistent AF, because non-pulmonary vein triggers which increase AF recurrence are frequently found in these patients. The major non-pulmonary vein triggers are from the left atrial posterior wall, left atrial appendage, ligament of Marshall, coronary sinus, superior vena cava, and crista terminalis, but other atrial sites can also generate AF triggers. All these sites have been known to contain atrial myocytes with potential arrhythmogenic electrical activity. The prevalence and clinical characteristics of these non-pulmonary vein triggers are well studied; however, the clinical outcome of catheter ablation for persistent AF is still unclear. Here, we reviewed the current ablation strategies for persistent AF and the clinical implications of major non-pulmonary vein triggers.

Long-term outcomes of left atrial appendage isolation using cryoballoon in persistent atrial fibrillation

AIMS

There is an increasing trend evaluating the role of non-pulmonary vein (PV) triggers to improve ablation outcomes in persistent atrial fibrillation (AF) as pulmonary vein isolation (PVI) strategy alone has modest outcomes. We investigated the long-term safety and efficacy of left atrial appendage isolation (LAAi) in addition to PVI using cryoballoon (CB) in persistent AF.

METHODS AND RESULTS

In this multicentre retrospective analysis, we included a total of 193 persistent AF patients (mean age: 60 ± 11 years, 50.3% females) who underwent PVI and LAAi using CB. Baseline and follow-up data including electrocardiography (ECG), 24 h Holter ECGs, and echocardiography were recorded for all patients. Atrial tachyarrhythmia (ATa) recurrence was defined as the detection of AF, atrial flutter, or atrial tachycardia (≥30 s) after a 3-month blanking period. At a median follow-up of 55 (36.5-60.0) months, 85 (67.9%) patients with PVI + LAAi were in sinus rhythm after the index procedure. Ischaemic stroke/transient ischemic attack occurred in 14 (7.2%) patients at a median of 24 (2-53) months following catheter ablation. Multivariate regression analysis revealed heart failure with preserved ejection fraction [hazard ratio (HR) 2.29, 95% confidence interval (CI) 1.04-5.02; P = 0.038], male gender (HR 0.53, 95% CI 0.29-0.96; P = 0.037), and LA area (HR 1.04, 95% CI 0.53-1.32; P = 0.023) as independent predictors of ATa recurrence.

CONCLUSION

Our findings demonstrated that the LAAi + PVI strategy using CB had acceptable long-term outcomes in patients with persistent AF. Systemic thrombo-embolic events are an important concern throughout the follow-up, which were mostly observed in case of non-adherence to anticoagulants.

Reverse structural left atrial remodeling and atrial tachycardia in patients with repeat ablation for atrial fibrillation

BACKGROUND

Catheter ablation has been evolved to a cornerstone in the therapy of atrial fibrillation (AF); however, atrial tachycardias (AT) after AF ablation are still an important issue. Besides the electrical recurrence of atrial tachyarrhythmia after ablation, left atrial (LA) remodeling has received attention as a consequence of AF.

OBJECTIVE

The aim of this study is to evaluate predictors for AT recurrence and LA remodeling in patients with repeat AF ablation procedures.

METHODS AND RESULTS

One hundred thirteen patients who underwent repeat AF ablation with 3D electro-anatomical mapping system were evaluated. Mean age was 63.1 ± 9.3 years, and 2.3 ± 0.5 ablation procedures were performed during a time period of 22 [IQR 7;48] months. Reverse structural LA remodeling (LA volume decreased more than 15%) was observed in 25 (22.1%) patients. LA volume index (LAVI) during first procedure was the only predictor for positive reverse structural LA remodeling (hazard ratio (HR): 1.03, 95% CI: 1.00-1.07, p = .036) in multivariate analysis. Fifty-nine (52.2%) patients experienced only AF and 54 (47.8%) patients AT after first procedure. Female gender (HR: 5.21, 95% CI: 1.66-18.08, p = .006), LAVI (HR: 1.06, 95% CI: 1.02-1.11, p = .008) and LA scar percentage (HR: 1.08, 95% CI: 1.02-1.17, p = .019) were independent significant predictors for AT recurrence in multivariate analysis.

CONCLUSIONS

Reverse structural LA remodeling occurred in a quarter of patients with repeat ablation procedures for AF. Only larger LAVI during first procedure predicted reverse structural LA remodeling. Half of the patients experienced AT between first and last ablation procedure. Female gender, larger LAVI and larger scar area were significant predictors for AT after catheter ablation for AF.

Intra- and Postprocedural Multimodality Imaging in Atrial Fibrillation

Multi-modality imaging plays critical roles during and after procedures associated with atrial fibrillation. Transesophageal echocardiography is an invaluable tool for left atrial appendage occlusion during the procedure and at follow-up. Both cardiac computed tomography and cardiac magnetic resonance contribute to postprocedural evaluation of pulmonary vein isolation ablation. The present review is the second of a 2-part series where we discuss the roles of cardiac imaging in the evaluation and management of patients with atrial fibrillation, focusing on intraprocedural and postprocedural assessment, including the clinical evidence and outcomes data supporting this future applications.

Long-term outcome of combined catheter ablation and left atrial appendage closure in atrial fibrillation patients

BACKGROUND

The combined procedure of catheter ablation and left atrial appendage closure (LAAC) aims to simultaneously control the heart rhythm and reduce the risk of strokes in patients with atrial fibrillation (AF). The study aims to evaluate the procedural safety and long-term outcome of the combined procedure in a large patient cohort.

METHODS

Clinical data of AF patients who underwent the combined procedure was retrospectively analyzed. Procedural and imaging follow-up parameters were compared between the transesophageal echocardiography-guided standard process and fluoroscopy-guided modified process, and between the single-seal WATCHMAN and dual-seal LACBES devices. Long-term outcomes included all-cause mortality, thromboembolic events, major bleeding, and recurrence of atrial tachyarrhythmias.

RESULTS

A total of 1114 patients were included. The rates of procedure-related major complications were comparable between the standard and modified processes (3.7% vs. 2.2%, p = 0.219), except for a higher incidence of respiratory depression in standard process group (0.9% vs 0%, p = 0.037), and between WATCHMAN and LACBES devices (2.4% vs. 3.3%, p = 0.535). The follow-up imaging evaluation revealed a high rate of satisfactory seals (99.7%) and a low rate of device related thrombus (1.9%), which were similar between two process groups and devices. The follow-up of over 1960 patient-years revealed low rates of mortality, thromboembolism, and nonprocedural major bleeding (1.8, 3.2, and 0.9 per 100 patient-years, respectively). Recurrent atrial tachyarrhythmias was observed in 23.9% patients.

CONCLUSIONS

The results supported the safety and long-term efficacy of the combined procedure of catheter ablation and LAAC. Fluoroscopy-guided LAAC device implantation may be considered in experienced centers.

Treatment Strategy in Atrial Tachycardia Originating From the Atrial Appendage

Background: Atrial appendage tachycardia (AAT) originating from the atrial appendage (AA) is extremely difficult to eliminate using radiofrequency catheter ablation (RFCA). The optimal management strategy for AAT refractory to RFCA remains unclear.

Objective: This study aims to investigate the long-term result of ablative therapy and the optimal alternative management for AAT refractory to RFCA.

Methods: A total of 51 patients with AAT originating from the AA undergoing RFCA were recruited. Video-assisted atrial appendectomy and oral ivabradine were performed on those with AATs refractory to RFCA, and this study aimed to evaluate their safety and long-term efficacy.

Results: We included 51 patients (51/586, 8.7%) with AATs confirmed by activation mapping and contrast venography. Among them, there were 28 (54.9%) AATs originating from the distal AA. In total, 14 (27.4%) AATs were refractory to RFCA, including 13 originating from the distal AA and one arising from the proximal AA. Ten of 11 (90.9%) AATs originating from the distal AA were eliminated after an atrial appendectomy, and the other three AATs were suppressed using oral ivabradine. Origins from the distal AA refractory to RFCA and early age of AAT onset ≤26.5 years indicated the need for atrial appendectomy. No major complications occurred, and nine patients with tachycardia-induced cardiomyopathy fully recovered. Long-term success was achieved in 98.0% of patients with multiple treatment managements.

Conclusion: AATs originating from the distal AA were more refractory to RFCA. RFCA was the cornerstone of AAT catheter ablation. Video-assisted thoracoscopic atrial appendectomy was an effective strategy for those origins at the distal AA and the age of AAT onset ≤26.5 years. Ivabradine represents a promising treatment for AAT temporarily in pediatric and young adult patients.

Transesophageal Echocardiography Following Left Atrial Appendage Electrical Isolation: Diagnostic Pitfalls and Clinical Implications

BACKGROUND

Following left atrial appendage (LAA) electrical isolation, the decision on whether to continue oral anticoagulation after successful atrial fibrillation ablation is based on the study of its mechanical function on transesophageal echocardiography (TEE). In this cohort, LAA contraction is absent and the incorrect interpretation of emptying flow velocities can lead to unwanted clinical sequelae.

METHODS

One hundred and sixty consecutive TEE exams performed to evaluate the LAA mechanical function following its electrical isolation were reviewed by an experienced operator blinded to the original diagnosis of LAA dysfunction. The rate of diagnostic discrepancy in the assessment LAA dysfunction and its clinical implications were evaluated.

RESULTS

Diagnostic discrepancy with misclassification of the LAA mechanical function occurred 36% (58/160) of TEE exams. In most cases (57/58), such discrepancy was observed in the setting of an incorrect original diagnosis of a normal LAA mechanical function despite absent/reduced or inconsistent LAA contraction. This main source of this wrong diagnosis was the wrong interpretation of passive LAA flows (34/57; 60%), followed by failure to identify dissociated firing (15/57; 26%). In rare cases (8/57; 14%), velocities of surrounding structures were interpreted as LAA flow due to misplacement of the pulsed-wave Doppler sample volume. Following LAA isolation, the proportion of patients who experienced a cerebrovascular event while off oral anticoagulation due to the misclassification of their LAA mechanical function was 70% (7/10 [95% CI, 40%-89%]).

CONCLUSIONS

Underdiagnosis of LAA mechanical dysfunction is common in TEEs performed following LAA electrical isolation, and it is associated with an increased risk of cerebrovascular events owing to oral anticoagulation discontinuation despite absent/reduced LAA contraction. Careful review of the TEE exam by an operator with specific expertise in LAA imaging and familiar with the functional implications of LAA isolation is necessary before interrupting oral anticoagulation in this cohort.

Hot or cold? Feasibility, safety, and outcome after radiofrequency-guided versus cryoballoon-guided left atrial appendage isolation

Background

Left atrial appendage (LAA) isolation (LAAI) has been described as an adjunctive ablation strategy for patients with recurrent atrial tachyarrhythmia (ATa).

Objectives

We compared the clinical impact of persistent durable LAAI between radiofrequency (RF)-guided wide-area LAAI and cryoballoon (CB)-guided ostial LAAI.

Methods

Consecutive patients who underwent RF- or CB-guided LAAI were retrospectively analyzed. RF-guided LAAI was performed by combining linear ablation. CB-guided LAAI was performed by LAA ostial ablation. Following LAAI, the patients underwent an invasive remapping study. LAA closure was conducted if persistent durability was confirmed. The procedural data, LAAI durability, and ATa recurrence were assessed.

Results

A total of 260 patients (RF: n = 201; CB: n = 59) undergoing LAAI were identified. The acute rate of procedural LAAI was higher in the CB group (CB:94.9% vs. RF:82.6%, p = .02) with a lower pericardial effusion incidence (CB:0% vs. RF:7.5%, p = .03). The 6-week durable LAAI was similar between the two groups (RF:78.3% vs. CB:66.0%, p = .103). During follow-up, one gastrointestinal bleeding and four stroke events including one subsequent intracranial bleeding leading to death occurred in the RF group, while one gastrointestinal bleeding occurred in the CB group.The 1-year ATa recurrence-free rate was higher in patients with durable LAAI following RF-guided LAAI (RF:76.3% vs. CB:56.7%, p = .0017). Multivariate analysis revealed RF-guided LAAI as a predictor of freedom from ATa recurrence (HR: 0.478, 95%CI: 0.336-0.823, p = .017).

Conclusions

LAAI can be more readily and safely achieved by CB-guided ostial ablation. In patients with confirmed LAAI, however, the freedom from ATa recurrence was higher after RF-guided wide-area isolation.

Long-Term Stroke Risk in Patients Undergoing Left Atrial Appendage Ablation With and Without Complete Isolation

Background: Catheter ablation (CA) for atrial fibrillation (AF), may require ablation beyond the pulmonary veins. Prior data suggest that additional LA ablation, particularly left atrial appendage (LAA) ablation, may alter atrial function leading to increased risk of ischemic stroke or transient ischemic attack (IS/TIA). We sought to study the long-term risk of IS/TIA in patients receiving ablation at the LAA compared to those receiving PVI alone and those receiving PVI with additional non-LAA locations. Methods: 350 patients who underwent CA for AF from 2008 to 2018 were included in the study. Locations of ablation in LA evaluated were the posterior wall, anterior wall, inferior wall, inter-atrial septum, lateral wall and the left atrial appendage (LAA). Patients undergoing LAA ablation were further divided as complete isolation (LAAi) and without complete isolation (LAAa). Results: Mean follow up of 4.8 years. In entire cohort, risk of IS/TIA was 1.62/100 patient-years (pys). The risk was highest in patients with LAAi (3.81/100 pys), followed by ablation LAAa (3.74/100 pys). Amongst all LA locations, only LAAi (HR 3.32, p = 0.03) and LAAa (HR 3.18, p = 0.02) were statistically significant predictors of IS/TIA after adjusting for OAC (Oral anticoagulant) use and baseline CHA2DS2VASc score. Conclusions: During long term follow-up, only ablation at the left atrial appendage with and without complete isolation was independently associated with an increased risk of IS/TIA in patients undergoing CA for AF. Potential strategies to reduce stroke risk, such as LAA closure, should be considered in these patients.

[Atrial fibrillation and the limits of oral anticoagulation: for whom are left atrial appendage occluders suitable?]

BACKGROUND

Patients with atrial fibrillation are at a significantly increased risk of thromboembolic events, especially ischemic strokes. Oral anticoagulation reduces this risk, but cannot be used in some patients for various reasons and is associated with a relevantly increased risk of bleeding. As an alternative for prophylaxis of thromboembolic events in patients with atrial fibrillation, there are different options of left atrial appendage closure.

AIM

This article explains the possibilities of interventional atrial occlusion as well as the suitable patient clientele using an overview of the currently available systems for atrial occlusion, a guideline for patient selection and a summary of the current scientific data.

CONCLUSION AND AVAILABLE SCIENTIFIC DATA

In carefully selected patients suffering from atrial fibrillation with relative or absolute contraindications for oral anticoagulation, interventional closure of the atrial appendage is a safe alternative for prophylaxis against thromboembolic events. The currently available scientific evidence from randomized controlled trials is sparse. Nevertheless, extensive amounts of registry study data suggest a benefit, while the results of several large randomized controlled trials are expected in the coming years.

[Left atrial appendage closure : Current data and future developments]

Catheter-based left atrial appendage closure (LAAC) is currently a potential treatment option for stroke prevention in patients with atrial fibrillation and high risk for stroke/embolism as well as high bleeding risk. Due to improvements in LAAC devices, advances in implantation techniques and growing experience of the interventional teams, the safety profile of LAAC has significantly improved in recent years. These developments have led to a currently comprehensive exploration of novel indications for LAAC, such as patients with atrial fibrillation and a low risk of hemorrhage, patients with atrial fibrillation after pulmonary vein ablation or patients after electrical isolation of the left atrial appendage. The treatment principle of closure of the left atrial appendage is supported by new data, which show the effectiveness of surgical closure of the left atrial appendage with respect to a reduction of the risk of stroke, at least partly in conjunction with oral anticoagulation during cardiological surgical interventions. Currently, the application in the clinical practice is reflected by a high degree of active studies. These randomized studies are testing the use of LAAC in new fields of application and together with the new developments in implantation techniques should define the optimal future use of the methods for the clinical practice. The current potential indications for the LAAC procedure, ongoing randomized clinical trials and advances in device development, implantation planning and technique as well as future developments in the field of LAAC treatment are summarized and discussed in this review article.

Stepwise endo-/epicardial catheter ablation for atrial fibrillation: The Mediterranea approach

BACKGROUND

Outcomes of catheter ablation (CA) among patients with nonparoxysmal atrial fibrillation (AF) are largely disappointing.

OBJECTIVE

We sought to evaluate the feasibility, effectiveness, and safety of a single-stage stepwise endo-/epicardial approach in patients with persistent/longstanding-persistent AF.

METHODS

We enrolled 25 consecutive patients with symptomatic persistent (n = 4) or longstanding-persistent (n = 21) AF and at least one prior endocardial procedure, who underwent CA using an endo-/epicardial approach. Our anatomical stepwise protocol included multiple endocardial as well as epicardial (Bachmann's bundle [BB] and ligament of Marshall ablations) components, and entailed ablation of atrial tachycardias emerging during the procedure. The primary outcome was freedom from any AF/atrial tachycardia episode after a 3-month blanking period. The secondary outcome was patients' symptom status during follow-up.

RESULTS

The stepwise endo-/epicardial approach allowed sinus rhythm restoration in 72% of patients, either directly (n = 6, 24%) or after AF organization into atrial tachycardia (n = 12, 48%). BB's ablation was commonly implicated in arrhythmia termination. After a median follow-up of 266 days (interquartile range, 96 days), survival free from AF/atrial tachycardia was 88%. Antiarrhythmic drugs could be discontinued in 22 patients (88%). As compared to baseline, more patients were asymptomatic at 9-month follow-up (0% vs. 56%, p = .02). Five patients (20%) developed mild medical complications, whereas one subject (4%) had severe kidney injury requiring dialysis.

CONCLUSION

A single-stage endo-/epicardial CA resulted in favorable rhythm and symptom outcomes in a cohort of patients with symptomatic persistent/longstanding-persistent AF and one or more prior endocardial procedures. Epicardial ablation of BB was commonly implicated in procedural success.

Atrial Remodeling in Atrial Fibrillation. Comorbidities and Markers of Disease Progression Predict Catheter Ablation Outcome

Atrial fibrillation is the most common supraventricular arrhythmia affecting an increasing proportion of the population in which mainstream therapy, i.e. catheter ablation, provides freedom from arrhythmia in only a limited number of patients. Understanding the mechanism is key in order to find more effective therapies and to improve patient selection. In this review, the structural and electrophysiological changes of the atrial musculature that constitute atrial remodeling in atrial fibrillaton and how risk factors and markers of disease progression can predict catheter ablation outcome will be discussed in detail.

Combination of ablation and left atrial appendage closure as "One-stop" procedure in the treatment of atrial fibrillation: Current status and future perspective

Atrial fibrillation (AF), the most common arrhythmia, is a major cause of stroke and systemic embolism. Left atrial appendage closure (LAAC) has been proved to be noninferior to traditional Vitamin K antagonists (VKAs) as well as novel oral anticoagulants (NOACs), which is becoming an important alternative to prevent stroke in non‐valvular AF. Catheter‐based AF ablation (CA) is recommended to be a standard of care in patients with AF refractory to drug therapy due to a better rhythm control and improvement of life quality than antiarrhythmic drugs. Theoretically, the one‐stop combination with LAAC and CA tends to bring more benefits in patients with AF, as it not only relieves symptoms, but also reduces the risk of stroke significantly. However, several important questions still need to be considered in the combination procedure although quite a few attempts have already been made in clinical practice. This review provides a comprehensive update on the concept, technique, perioperative management, benefits and other critical issues of the “one‐stop” procedure.

Ablation of mitral annular flutter ablation utilizing a left atrial anterior line versus a lateral mitral isthmus line: a systematic review and meta-analysis

Purpose

Mitral annular flutter (MAF) is a common arrhythmia after atrial fibrillation ablation. We sought to compare the efficacy and safety of catheter ablation utilizing either a left atrial anterior wall (LAAW) line or a lateral mitral isthmus (LMI) line.

Methods

We performed a systematic review for all studies that compared LAAW versus LMI lines. Risk ratio (RR) and mean difference (MD) 95% confidence intervals were measured for dichotomous and continuous variables, respectively.

Results

Four studies with a total of 594 patients were included, one of which was a randomized control trial. In the LMI ablation group, 40% of patients required CS ablation. There were no significant differences in bidirectional block (RR 1.26; 95% CI, 0.94–1.69) or ablation time (MD −1.5; 95% CI, −6.11–3.11), but LAAW ablation was associated with longer ablation line length (MD 11.42; 95% CI, 10.69–12.14) and longer LAA activation delay (MD 67.68; 95% CI, 33.47–101.89.14) when compared to LMI. There was no significant difference in pericardial effusions (RR 0.36; 95% CI, 0.39–20.75) between groups and more patients were maintained sinus rhythm (RR 1.19; 95% CI, 1.03–1.37, p = 0.02) who underwent LAAW compared to LMI.

Conclusion

Ablation of mitral annular flutter with a LAAW line compared to a LMI line showed no difference in rates of acute bidirectional block, ablation time, or pericardial effusion. However, LAAW ablation required a longer ablation line length, resulted in greater LAA activation delayed and was associated with more sinus rhythm maintenance, with the added advantage of avoiding ablation in the CS.

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.

Concomitant epicardial left atrial appendage ligation and left atrial ablation of atrial fibrillation: Safety, feasibility and outcome

Introduction

We present initial results of patients undergoing a combined procedure of epicardial LAA ligation in addition to left atrial ablation for AF.

Methods

9 patients were included for additional use of LARIAT as an individual treatment approach for AF. First an epicardial LAA ligation was performed, in the same procedure left atrial ablations consisting of PVI and additional substrate based modifying ablations were performed. Follow–up at 3 months and 12 months was performed.

Results

There was only 1 minor procedural complication (11%) involving epicardial bleeding and 2 late adverse events of pericardial tamponade and stroke. At the final follow-up (median 20 months) 7 patients were in stable sinus rhythm (78%) and 2 pts had reduced AF burden.

Conclusion

Concomitant epicardial LAA ligation and ablation is feasible in selected patients with a reasonable risk profile. More prospective data are required to validate the safety and efficacy.

Clinical impact of eliminating nonpulmonary vein triggers of atrial fibrillation and nonpulmonary vein premature atrial contractions at initial ablation for persistent atrial fibrillation

BACKGROUND

The role of nonpulmonary vein (PV) triggers ablation in persistent atrial fibrillation (PEAF) was suggested but it is still under debate.

OBJECTIVES

We aimed to assess the effectiveness of non-PV trigger-targeted ablation for patients with PEAF.

METHODS

Consecutive patients with PEAF undergoing catheter ablation (CA) between January 2015 and April 2017 were enrolled. Isoproterenol plus adenosine challenge was performed to provoke non-PV triggers. Non-PV triggers were defined as the trigger beats inducing AF (non-PV AF triggers) and/or frequent premature contractions (non-PV PACs) from other than PVs. Three groups were defined: Group 1 (n = 186) without non-PV triggers; Group 2 (n = 65) with non-PV triggers that could be completely eliminated with CA; Group 3 (n = 49) with non-PV triggers still inducible after CA. The primary endpoint was freedom from any atrial tachyarrhythmia (ATa) recurrence.

RESULTS

A total of 300 patients (230 males, age 64 ± 10) were enrolled. The mean follow-up period was 27 ± 10 months. Freedom from ATa recurrence at 1 and 2 years were significantly lower in Group 3 compared to the other two groups (Group 1; 74.7%, 67.2% vs. Group 2; 75.8%, 68.3% vs. Group 3: 52.1%, 38.6%, p = .0005), irrespective of the type of non-PV triggers (non-PV AF triggers vs. non-PV PACs). On multivariate analysis, unsuccessful elimination of non-PV triggers was an independent predictor for ATa recurrence (hazard ratio = 1.80, 95% confidence interval = 1.07-2.95, p = .026).

CONCLUSION

Successful non-PV triggers elimination can improve the ATa recurrence rate in PEAF ablation. ATa recurrence rate is higher, if non-PV AF triggers or even non-PV PACs remain in patients with PEAF.

Evaluation of Left Atrial Appendage Isolation Using Cardiac MRI after Catheter Ablation of Atrial Fibrillation: Paradox of Appendage Reservoir

Objective

To assess the effect of left atrial appendage (LAA) isolation on LAA emptying and left atrial (LA) function using cardiac MRI in patients who underwent successful catheter ablation of atrial fibrillation (AF).

Materials and Methods

This retrospective study included 84 patients (mean age, 59 ± 10 years; 67 males) who underwent cardiac MRI after successful catheter ablation of AF. According to the electrical activity of LAA after catheter ablation, patients showed either LAA isolation or LAA normal activity. The LAA emptying phase (LAA-EP, in the systolic phase [SP] or diastolic phase), LAA emptying flux (LAA-EF, mL/s), and LA ejection fraction (LAEF, %) were evaluated by cardiac MRI.

Results

Of the 84 patients, 61 (73%) and 23 (27%) patients showed LAA normal activity and LAA isolation, respectively. Incidence of LAA emptying in SP was significantly higher in LAA isolation (91% vs. 0%, p < 0.001) than in LAA normal activation. LAA-EF was significantly lower in LAA isolation (40.1 ± 16.2 mL/s vs. 80.2 ± 25.1 mL/s, p < 0.001) than in LAA normal activity. Furthermore, LAEF was significantly lower in LAA isolation (23.7% ± 11.2% vs. 31.1% ± 16.6%, p = 0.04) than in LAA normal activity. Multivariate analysis demonstrated that the LAA-EP was independent from LAEF (p = 0.01).

Conclusion

LAA emptying in SP may be a critical characteristic of LAA isolation, and it may adversely affect the LAEF after catheter ablation of AF.

Thromboembolism after electrical isolation of the left atrial appendage: a new indication for interventional closure?

AIMS

Left atrial appendage electrical isolation (LAAI) may improve the rhythm outcome in selected patients with atrial fibrillation (AF). Controversy exists if LAAI is associated with an increased rate of thromboembolic complications. We sought to assess the feasibility, efficacy, and safety of interventional left atrial appendage closure (LAAC) in comparison to oral anticoagulation (OAC) after electrical LAAI.

METHODS AND RESULTS

Weeks after index LAAI using the cryoballoon or a linear maze like ablation strategy patients' left atrial appendage was invasively remapped. In case of persistent LAAI, LAAC was performed. Patients who refused invasive remapping continued OAC. The primary endpoint was composed of any stroke or systemic embolism (SE) and the occurrence of intracardiac thrombus. Secondary endpoints included stroke/SE, major bleeding, and all-cause death. Of 166 patients (51% female; mean age 70 ± 8 years; mean CHAD2S2VASc score 3.4 ± 1.8) after LAAI, 94 patients received LAAC (LAAC group) and 72 continued OAC (no LAAC). After LAAC, 83% of patients received dual antiplatelet therapy for 6 weeks and aspirin thereafter. During a mean follow-up of 778 ± 630 days, 5 and 11 primary endpoint events were observed in the LAAC and no LAAC group, respectively [hazard ratio (HR) 0.27, 95% confidence interval (CI) 0.10-0.75; P = 0.010]. The calculated annual thromboembolic event rates were 6.9% (no LAAC) and 2.3% (LAAC), respectively. Left atrial appendage closure significantly reduced the incidence of stroke and SE (HR 0.31, CI 0.1-0.98; P = 0.04).

CONCLUSION

After electrical LAAI for rhythm control in AF patients, interventional LAAC was associated with fewer thromboembolic complications when compared with OAC.

An Appreciation of Anatomy in the Molecular World

Robert H. Anderson is one of the most important and accomplished cardiac anatomists of the last decades, having made major contributions to our understanding of the anatomy of normal hearts and the pathologies of acquired and congenital heart diseases. While cardiac anatomy as a research discipline has become largely subservient to molecular biology, anatomists like Professor Anderson demonstrate anatomy has much to offer. Here, we provide cases of early anatomical insights on the heart that were rediscovered, and expanded on, by molecular techniques: migration of neural crest cells to the heart was deduced from histological observations (1908) and independently shown again with experimental interventions; pharyngeal mesoderm is added to the embryonic heart (1973) in what is now defined as the molecularly distinguishable second heart field; chambers develop from the heart tube as regional pouches in what is now considered the ballooning model by the molecular identification of regional differentiation and proliferation. The anatomical discovery of the conduction system by Purkinje, His, Tawara, Keith, and Flack is a special case because the main findings were never neglected in later molecular studies. Professor Anderson has successfully demonstrated that sound knowledge of anatomy is indispensable for proper understanding of cardiac development.

Catheter ablation for atrial fibrillation: current indications and evolving technologies

Catheter ablation for atrial fibrillation (AF) has emerged as an important rhythm-control strategy and is by far the most common cardiac ablation procedure performed worldwide. Current guidelines recommend the procedure in symptomatic patients with paroxysmal or persistent AF who are refractory or intolerant to antiarrhythmic drugs. The procedure might also be considered as a first-line approach in selected asymptomatic patients. Data from large registries indicate that AF ablation might reduce mortality and the risk of heart failure and stroke, but evidence from randomized controlled trials is mixed. Pulmonary vein isolation using point-by-point radiofrequency or with the cryoballoon remains the cornerstone technique in AF ablation. Additional atrial ablation can be performed in patients with persistent AF, but its benefits are largely unproven. Technological advances in the past decade have focused on achieving durable vein isolation, reducing procedure duration and improving safety. Numerous exciting new technologies are in various stages of development. In this Review, we discuss the relevant data to support the recommended and evolving indications for catheter ablation of AF, describe the different ablation techniques, and highlight the latest advances in technology that aim to improve its safety and efficacy. We also discuss lifestyle modification strategies to improve ablation outcomes.

Long-standing Persistent Atrial Fibrillation Ablation in a Patient With High Risk of Bleeding

A 57 year-old patient with dilated cardiomyopathy, long-standing persistent atrial fibrillation, heart failure and episodes of gastrointestinal bleeding underwent AF ablation with pulmonary vein isolation, homogeneization of septal scar, posterior wall isolation and also left atrial appendage isolation. Additionally, because of the high risk of embolism, underwent left atrial appendage occlusion.

Atrial fibrillation ablation in patients with pulmonary lobectomy or pneumectomy: Procedural challenges and efficacy

BACKGROUND

Catheter ablation of atrial fibrillation (AF) in patients with pulmonary lobectomy or pneumectomy is challenging due to anatomical alterations. After lung resection, electrically active pulmonary vein (PV) stumps remain and need to be localized for PV isolation (PVI). The present study aims to describe clinical challenges of PVI in patients with pulmonary lobectomy or pneumectomy.

METHODS

We performed a retrospective study on 19 patients with previous pulmonary lobectomy or pneumectomy undergoing catheter ablation for AF in three German hospitals.

RESULTS

Nineteen patients with paroxysmal, persistent, or longstanding-persistent AF and history of pulmonary lobectomy (n = 11) or pneumectomy (n = 8) were enrolled. Catheter ablation was performed as radiofrequency (RF) ablation using 3D mapping, robotic RF ablation, or by using balloon devices. Decent anatomical changes were observed in patients with lobectomy while cardiac rotation and mediastinal shifting was dominant in patients with pneumectomy. Visualization of all PVs including PV stumps by PV angiography was possible in 10 of 19 patients (52.6%). PV spikes were observed in all identified PV remnants. In nine patients (47.4%), at least one PV remnant could not be identified and electrical isolation was not performed. During 24 months follow-up, patients with incomplete PVI had a significantly shorter arrhythmia-free survival than patients with complete PVI (76.2% [95% Confidence interval (CI) 47.2-100.0%] vs 40.0% [95% CI 5.6-74.1%], P = .043).

CONCLUSION

In patients with AF and previous lobectomy or pneumectomy, identification and isolation of all PVs are challenging but crucial for ablation success. Additional imaging techniques may be necessary to achieve complete PVI.