Pulmonary vein isolation and autonomic denervation for the management of paroxysmal atrial fibrillation by a minimally invasive surgical approach

Narrative Review: Surgical and Hybrid Management of Atrial Fibrillation

Although significant strides have been made in non-pharmacologic management of atrial fibrillation (AF), these treatments remain a work in progress. While catheter ablation is often effective for management of paroxysmal AF, it is less successful in patients with persistent or longstanding persistent AF. This review was undertaken to clarify the risks, benefits, and alternatives to catheter ablation for non-pharmacologic AF management. In order to clarify the roles of surgical and hybrid ablation, this narrative review was undertaken by searching MEDLINE to identify peer-reviewed clinical trials, randomized controlled trials, meta-analyses, review articles, and other clinically relevant studies. The search was limited to English-language reports published between 1960 and 2023. Atrial fibrillation was searched using the terms surgical ablation, catheter ablation, hybrid ablation, stroke prevention, left atrial occlusion, and atrial excision. Google and Google Scholar, as well as bibliographies of identified articles, were also reviewed for additional references. The Cox-maze surgical approach is still the most efficacious non-pharmacological treatment for AF. Hybrid ablation, combining cardiac surgical and catheter ablation techniques, has become an attractive option for persistent or longstanding persistent AF.

The Society of Thoracic Surgeons 2023 Clinical Practice Guidelines for the Surgical Treatment of Atrial Fibrillation

The Society of Thoracic Surgeons 2023 Clinical Practice Guidelines for the Surgical Treatment of Atrial Fibrillation incorporate the most recent evidence for surgical ablation and left atrial appendage occlusion in different clinical scenarios. Substantial new evidence regarding the risks and benefits of surgical left atrial appendage occlusion and the long-term benefits of surgical ablation has been produced in the last 5 years. Compared with the 2017 clinical practice guideline, the current update has an emphasis on surgical ablation in first-time, nonemergent cardiac surgery and its long-term benefits, an extension of the recommendation to perform surgical ablation in all patients with atrial fibrillation undergoing first-time, nonemergent cardiac surgery, and a new class I recommendation for left atrial appendage occlusion in all patients with atrial fibrillation undergoing first-time, nonemergent cardiac surgery. Further guidance is provided for patients with structural heart disease and atrial fibrillation being considered for transcatheter valve repair or replacement, as well as patients in need of isolated left atrial appendage management who are not candidates for surgical ablation. The importance of a multidisciplinary team assessment, treatment planning, and long-term follow-up are reiterated in this clinical practice guideline with a class I recommendation, along with the other recommendations from the 2017 guidelines that remained unchanged in their class of recommendation and level of evidence.

Hybrid Totally Thoracoscopic Maze and Catheter Ablation for Persistent Atrial Fibrillation: Initial Experience

Atrial fibrillation is now a pandemic in our ageing community. Although James L. Cox devised a surgical procedure with near-universal curative success in 1987, catheter-based interventions have flourished. For persistent atrial fibrillation (AF), however, an isolated endocardial approach has limitations: procedural times are long, carry risk, and the outcomes are not durable. By combining left atrial endocardial and epicardial interventions with staged mapping, we optimise the benefits of both approaches. Our initial series of hybrid ablation for persistent atrial fibrillation reports excellent early outcomes, freedom from complications and excellent success at follow-up.

Intrinsic Cardiac Neuromodulation in the Management of Atrial Fibrillation- A Potential Missing Link?

Atrial fibrillation (AF) is the most common supraventricular arrhythmia that is linked with higher cardiovascular morbidity and mortality. Recent evidence has demonstrated that catheter-based pulmonary vein isolation (PVI) is not only a viable alternative but may be superior to antiarrhythmic drug therapy for long-term freedom from symptomatic AF episodes, a reduction in the arrhythmia burden, and healthcare resource utilization with a similar risk of adverse events. The intrinsic cardiac autonomic nervous system (ANS) has a significant influence on the structural and electrical milieu, and imbalances in the ANS may contribute to the arrhythmogenesis of AF in some individuals. There is now increasing scientific and clinical interest in various aspects of neuromodulation of intrinsic cardiac ANS, including mapping techniques, ablation methods, and patient selection. In the present review, we aimed to summarize and critically appraise the currently available evidence for the neuromodulation of intrinsic cardiac ANS in AF.

Minimally-invasive cardiac surgery: a bibliometric analysis of impact and force to identify key and facilitating advanced training

Background

The number of citations an article receives is a marker of its scientific influence within a particular specialty. This bibliometric analysis intended to recognise the top 100 cited articles in minimally-invasive cardiac surgery, to determine the fundamental subject areas that have borne considerable influence upon clinical practice and academic knowledge whilst also considering bibliometric scope. This is increasingly relevant in a continually advancing specialty and one where minimally-invasive cardiac procedures have the potential for huge benefits to patient outcomes.

Methods

The Web of Science (Clarivate Analytics) data citation index database was searched with the following terms: [Minimal* AND Invasive* AND Card* AND Surg*]. Results were limited to full text English language manuscripts and ranked by citation number. Further analysis of the top 100 cited articles was carried out according to subject, author, publication year, journal, institution and country of origin.

Results

A total of 4716 eligible manuscripts were retrieved. Of the top 100 papers, the median (range) citation number was 101 (51–414). The most cited paper by Lichtenstein et al. (Circulation 114(6):591–596, 2006) published in Circulation with 414 citations focused on transapical transcatheter aortic valve implantation as a viable alternative to aortic valve replacement with cardiopulmonary bypass in selected patients with aortic stenosis. The Annals of Thoracic Surgery published the most papers and received the most citations (n = 35; 3036 citations). The United States of America had the most publications and citations (n = 52; 5303 citations), followed by Germany (n = 27; 2598 citations). Harvard Medical School, Boston, Massachusetts, published the most papers of all institutions. Minimally-invasive cardiac surgery pertaining to valve surgery (n = 42) and coronary artery bypass surgery (n = 30) were the two most frequent topics by a large margin.

Conclusions

This work establishes a comprehensive and informative analysis of the most influential publications in minimally-invasive cardiac surgery and outlines what constitutes a citable article. Undertaking a quantitative evaluation of the top 100 papers aids in recognising the contributions of key authors and institutions as well as guiding future efforts in this field to continually improve the quality of care offered to complex cardiac patients.

Long-term results of thoracoscopic ablation of paroxysmal atrial fibrillation: is the glass half full or half empty?

OBJECTIVES

Previous series showed the outcomes of thoracoscopic ablation of stand-alone symptomatic paroxysmal atrial fibrillation (AF) for up to 7 years of follow-up. The goal of this study was to assess the long-term durability of surgical pulmonary vein isolation (PVI) beyond 7 years.

METHODS

Fifty consecutive patients {mean age 55 [standard deviation (SD): 11.2] years, previous catheter ablation in 56%, left ventricular ejection fraction 60% (SD: 4.6), left atrium volume 65 ml (SD: 17)} with stand-alone symptomatic paroxysmal AF underwent PVI through bilateral thoracoscopy ablation between 2005 and 2014. The CHA2DS2-VASc score was ≥2 in 12 patients (24%).

RESULTS

No hospital deaths occurred. At hospital discharge all patients but 1 (2%) were in sinus rhythm (SR). Follow-up was 100% complete [mean 8.4 years (SD: 2.3), max 15]. The 8-year cumulative incidence function of AF recurrence, with death as a competing risk, on or off class I/III antiarrhythmic drugs (AADs)/electrocardioversion/re-transcatheter ablation (TCA) was 20% (SD: 5; 95% confidence interval: 10, 32); and off class I/III AADs/electrocardioversion/re-TCA was 52% (SD: 7; 95% confidence interval: 0.83, 8.02). At 8 years, the predicted prevalence of patients in SR was 87% and 53% were off class I/III AADs/electrocardioversion/re-TCA. The recurrent arrhythmia was AF in all patients except 2, who had atypical atrial flutter (4%). No predictors of AF recurrence were identified. At the last follow-up, 76% of the patients showed European Heart Rhythm Association class I. No strokes or thromboembolic events were documented and 76% of the subjects were off anticoagulation therapy.

CONCLUSIONS

Despite a considerable AF recurrence rate, our single-centre, long-term outcome of surgical PVI showed encouraging data, with the majority of patients remaining in SR, although many of them were on antiarrhythmic therapy.

The Convergent Procedure: A Unique Multidisciplinary Hybrid Treatment of Atrial Fibrillation

The convergent procedure is a hybrid ablation treatment for atrial fibrillation. It is increasingly considered as a management option for patients with persistent and long-standing atrial fibrillation. It consists of surgical ablation of the posterior left atrium through a minimally invasive closed-chest approach followed by endocardial catheter ablation. It is increasingly performed with concurrent epicardial occlusion of the left atrial appendage with a video-assisted thoracoscopic technique to physically and electrically isolate the left atrial appendage. This article provides an overview of a multidisciplinary approach to the convergent procedure, with concurrent thoracoscopic closure of the left atrial appendage, with an emphasis on perioperative management at a single institution. It provides a literature review of procedural outcomes, current data limitations, and future considerations.

Autonomic Nervous System Dysfunction: JACC Focus Seminar

Autonomic nervous system control of the heart is a dynamic process in both health and disease. A multilevel neural network is responsible for control of chronotropy, lusitropy, dromotropy, and inotropy. Intrinsic autonomic dysfunction arises from diseases that directly affect the autonomic nerves, such as diabetes mellitus and the syndromes of primary autonomic failure. Extrinsic autonomic dysfunction reflects the changes in autonomic function that are secondarily induced by cardiac or other disease. An array of tests interrogate various aspects of cardiac autonomic control in either resting conditions or with physiological perturbations from resting conditions. The prognostic significance of these assessments have been well established. Clinical usefulness has not been established, and the precise mechanistic link to mortality is less well established. Further efforts are required to develop optimal approaches to delineate cardiac autonomic dysfunction and its adverse effects to develop tools that can be used to guide clinical decision-making.

Safety and long-term efficacy of thoracoscopic Epicardial ablation in patients with paroxysmal atrial fibrillation: a retrospective study

Background

The aim of this study is to report the long-term efficacy and safety of thoracoscopic epicardial left atrial ablation (TELA) in patients with paroxysmal atrial fibrillation (AF).

Methods

This was a retrospective review of medical records. We included all patients diagnosed with paroxysmal AF who underwent TELA at our institution between 04/2011 and 06/2017. TELA included pulmonary vein isolation, LA dome lesions and LA appendage exclusion. All (n = 55) patients received an implantable loop recorder (ILR), 30 days post-operatively. Antiarrhythmic and anticoagulation therapy were discontinued at 90 and 180 days postoperatively, respectively, if patients were free of AF recurrence. Failure was defined as ≥two minutes of continuous AF, or atrial tachycardia.

Results

Fifty-five patients (78% males, mean age = 61.6 years) qualified for the study. The average duration in AF was 3.64 +/− 3.4 years, mean CHA2DS2-VASc Score was 2.0 +/− 1.6. The procedure was attempted in 57 patients and completed successfully in 55 (96.5%). Two patients experienced a minor pulmonary vein bleed that was managed conservatively. Post procedure, one patient experienced pulmonary edema, another experienced a pneumothorax requiring a chest tube and another experienced acute respiratory distress syndrome resulting in longer hospitalization. Otherwise, there were no major procedural complications. Success rates were 89.1% (n = 49/55), 85.5% (n = 47/55) and 76.9% (n = 40/52) at 6, 12 and 24 months, respectively. In the multivariate cox-proportional hazard model, survival at the mean of covariates was 86 and 74% at 12 and 24 months, respectively.

Conclusion

In this single center experience, TELA was a safe and efficacious procedure for patients with paroxysmal AF.

Neuromodulation for Ventricular Tachycardia and Atrial Fibrillation: A Clinical Scenario-Based Review

Autonomic dysregulation in cardiovascular disease plays a major role in the pathogenesis of arrhythmias. Cardiac neural control relies on complex feedback loops consisting of efferent and afferent limbs, which carry sympathetic and parasympathetic signals from the brain to the heart and sensory signals from the heart to the brain. Cardiac disease leads to neural remodeling and sympathovagal imbalances with arrhythmogenic effects. Preclinical studies of modulation at central and peripheral levels of the cardiac autonomic nervous system have yielded promising results, leading to early stage clinical studies of these techniques in atrial fibrillation and refractory ventricular arrhythmias, particularly in patients with inherited primary arrhythmia syndromes and structural heart disease. However, significant knowledge gaps in basic cardiac neurophysiology limit the success of these neuromodulatory therapies. This review discusses the recent advances in neuromodulation for cardiac arrhythmia management, with a clinical scenario-based approach aimed at bringing neurocardiology closer to the realm of the clinical electrophysiologist.

Catheter Ablation of Long-standing Persistent Atrial Fibrillation: a Reckless Challenge or a Way to Real Cure?

Long-standing persistent atrial fibrillation (L-PeAF) is a category in which rhythm control is attempted while atrial fibrillation (AF) is maintained for more than 1 year. Because AF is a progressive disease and L-PeAF accompanies significant electrical and structural remodeling of atria, it is difficult to restore and maintain sinus rhythm in patients with L-PeAF. Nonetheless, the rhythm outcome is being increasingly improved by the development of sophisticated mapping devices, highly efficient catheters, and evidence-based ablation strategies, and the rational choice of patient selection criteria. This review discusses the evolution of the rhythm control outcome of L-PeAF and its future direction of development.

Predictive risk factors for recurrent atrial fibrillation after modified endoscopic ablation: A 2-year follow-up

BACKGROUND

Our previous study reported a modified endoscopic procedure for nonvalvular atrial fibrillation (AF) that requires only 3 ports in the left chest wall.

HYPOTHESIS

Certain preoperative variables might be predictive risk factors for AF recurrence among patients who underwent this procedure.

METHODS

From October 2010 to April 2014, 114 patients with either paroxysmal AF (PAF) or nonparoxysmal AF (non-PAF) underwent the procedure and completed postoperative cardiac-rhythm measurement via electrocardiography and Holter monitoring. Univariate and multivariate analyses of the possible AF-related risk factors were conducted.

RESULTS

During 2-year follow-up, 99 of 114 patients (86.8%) were free from atrial tachyarrhythmia. Results from univariate analyses showed that AF duration, left atrial diameter (LAD), left atrial minimum volume, left atrial empty fraction, left atrial expansion index, and left atrial active empty fraction (LAAEF) were significantly associated with postoperative AF recurrence. Results from multivariate analyses showed that AF duration (odds ratio [OR]: 1.194, 95% CI: 1.063-1.340, P = 0.003), LAD (OR: 1.101, 95% CI: 1.005-1.205, P = 0.039), and LAAEF (OR: 0.490, 95% CI: 0.277-0.865, P = 0.014) were independent risk factors. There was no difference in AF recurrence between patients with PAF and non-PAF (P = 0.250).

CONCLUSIONS

Our 2-year follow-up study suggested that low LAAEF, long AF duration, and large LAD might be potential predictive risk factors for AF recurrence. Patients with PAF and non-PAF had a similar AF recurrence rate after modified endoscopic ablation.

Assessment of the effect of left atrial cryoablation enhanced by ganglionated plexi ablation in the treatment of atrial fibrillation in patients undergoing open heart surgery

BACKGROUND

The aim of our study was to investigate, whether enhancement of left atrial cryoablation by ablation of the autonomic nervous system of left atrium leads to influencing the outcomes of surgical treatment of atrial fibrillation in patients with structural heart disease undergoing open-heart surgery.

METHODS

The observed patient file consisted of 100 patients, who have undergone a combined open-heart surgery at our department between July 2012 and December 2014. The patients were indicated for the surgical procedure due to structural heart disease, and suffered from paroxysmal, persistent, or long-standing persistent atrial fibrillation. In all cases, left atrial cryoablation was performed in the extent of isolation of pulmonary veins, box lesion, connecting lesion with mitral annulus, amputation of the left atrial appendage and connecting lesion of the appendage base with left pulmonary veins. Furthermore, 35 of the patients underwent mapping and radiofrequency ablation of ganglionated plexi, together with discision and ablation of the ligament of Marshall (Group GP). A control group was consisted of 65 patients without ganglionated plexi intervention (Group LA). The main primary outcome was establishment and duration of sinus rhythm in the course of one-year follow-up.

RESULTS

Evaluation of the number of patients with a normal sinus rhythm in per cent has shown comparable values in both groups (Group GP - 93.75%, Group LA - 86.67%, p = 0.485); comparable results were also observed in patients with normal sinus rhythm without anti-arrhythmic treatment in the 12th month (Group GP - 50%, Group LA - 47%, p = 0.306). We have not observed any relation between the recurrence of atrial fibrillation and the presence of a mitral valve surgery, or between the presence of a mitral and tricuspid valves surgery and between the left atrial diameter > 50 mm.

CONCLUSIONS

Enhancement of left atrial cryoablation by gangionated plexi ablation did not influence the outcomes of surgical ablation due to atrial fibrillation in our population in the course of 12-month follow-up.

TRIAL REGISTRATION

The study was approved retrospectively by the Ethics Committee of the University Hospital Ostrava ( reference number 867/2016).

The Society of Thoracic Surgeons 2017 Clinical Practice Guidelines for the Surgical Treatment of Atrial Fibrillation

EXECUTIVE SUMMARY

Surgical ablation for atrial fibrillation (AF) can be performed without additional risk of operative mortality or major morbidity, and is recommended at the time of concomitant mitral operations to restore sinus rhythm. (Class I, Level A) Surgical ablation for AF can be performed without additional operative risk of mortality or major morbidity, and is recommended at the time of concomitant isolated aortic valve replacement, isolated coronary artery bypass graft surgery, and aortic valve replacement plus coronary artery bypass graft operations to restore sinus rhythm. (Class I, Level B nonrandomized) Surgical ablation for symptomatic AF in the absence of structural heart disease that is refractory to class I/III antiarrhythmic drugs or catheter-based therapy or both is reasonable as a primary stand-alone procedure, to restore sinus rhythm. (Class IIA, Level B randomized) Surgical ablation for symptomatic persistent or longstanding persistent AF in the absence of structural heart disease is reasonable, as a stand-alone procedure using the Cox-Maze III/IV lesion set compared with pulmonary vein isolation alone. (Class IIA, Level B nonrandomized) Surgical ablation for symptomatic AF in the setting of left atrial enlargement (≥4.5 cm) or more than moderate mitral regurgitation by pulmonary vein isolation alone is not recommended. (Class III no benefit, Level C expert opinion) It is reasonable to perform left atrial appendage excision or exclusion in conjunction with surgical ablation for AF for longitudinal thromboembolic morbidity prevention. (Class IIA, Level C limited data) At the time of concomitant cardiac operations in patients with AF, it is reasonable to surgically manage the left atrial appendage for longitudinal thromboembolic morbidity prevention. (Class IIA, Level C expert opinion) In the treatment of AF, multidisciplinary heart team assessment, treatment planning, and long-term follow-up can be useful and beneficial to optimize patient outcomes. (Class I, Level C expert opinion).

Ganglionated Plexi Ablation: Physiology and Clinical Applications

Ganglionated plexi (GP), consisting of conglomerations of autonomic ganglia on the epicardial surface of the heart, have been shown to play a significant role in different arrhythmias, including atrial fibrillation. GP ablation has become an adjunctive procedure in the treatment of atrial fibrillation, while it has been used successfully in preliminary studies in vasovagal syncope. This review will present the current data on the physiology and clinical applications of GP ablation in the treatment of atrial fibrillation and other diseases.

Clinical neurocardiology defining the value of neuroscience-based cardiovascular therapeutics

The autonomic nervous system regulates all aspects of normal cardiac function, and is recognized to play a critical role in the pathophysiology of many cardiovascular diseases. As such, the value of neuroscience-based cardiovascular therapeutics is increasingly evident. This White Paper reviews the current state of understanding of human cardiac neuroanatomy, neurophysiology, pathophysiology in specific disease conditions, autonomic testing, risk stratification, and neuromodulatory strategies to mitigate the progression of cardiovascular diseases.

Is the Atrial Neural Plexis a Therapeutic Target in Atrial Fibrillation?

Circumferential pulmonary vein isolation is the mainstay of atrial fibrillation (AF) ablation, but alternative approaches and techniques have been developed to improve the outcomes. One of these additional ablation targets are ganglionated plexi of the intrinsic cardiac autonomic system that contain a variety of sympathetic and parasympathetic neurons that communicate with the extrinsic cardiac autonomic nervous system. The ganglionated plexi of the heart do not serve as a simple relay station but could modulate the autonomic interaction between the extrinsic and intrinsic cardiac autonomic system. Intrinsic cardiac autonomic nerve activity is an invariable trigger of paroxysmal atrial tachyarrhythmia, including atrial fibrillation. Although multiple studies have shown that ganglionated plexi play an important role in initiating atrial fibrillation, there is no consensus on a standardized protocol for selecting target sites and determining how ganglionated plexi ablation can best be accomplished. Recent clinical trials have demonstrated the feasibility and efficacy of ganglionated plexi ablation in addition to pulmonary vein isolation, but novel technologies and strategies are necessary to improve the current ablation techniques in managing patients with atrial fibrillation. This review focuses on the relationship between atrial ganglionated plexi and atrial fibrillation and the potential benefits and limitations of ganglionated plexi ablation in the management of atrial fibrillation.

Total endoscopic ablation of patients with long-standing persistent atrial fibrillation: a randomized controlled study

OBJECTIVES

Total endoscopic ablation of atrial fibrillation is an alternative to catheter ablation, but its clinical role needs further evaluation. The aim of this study was to compare total endoscopic ablation with rate control in patients with long-standing persistent atrial fibrillation and to examine the effect of endoscopic ablation on heart rhythm, symptoms, physical working capacity and myocardial function during 1 year of follow-up.

METHODS

In a prospective controlled study, 36 patients aged >50 years with symptomatic long-standing persistent atrial fibrillation were randomized to either total endoscopic ablation (n = 17, after two drop-outs before ablation n = 15) or rate control therapy (n = 19). In the ablation group, a box lesion encircling the pulmonary veins was performed, using temperature-controlled radiofrequency energy. Loop recorders were implanted in all patients. Echocardiography and quality-of-life assessment were performed at 6 and 12 months, and physical working capacity assessment at 6 months.

RESULTS

There was no mortality or thromboembolic event. In the control group, all patients were in permanent atrial fibrillation during 12 months of follow-up. In the ablation group, the proportion of patients in sinus rhythm without antiarrhythmic drugs was 12/15 (80%) at 12 months. The median freedom of atrial fibrillation at 3-12 months was 95% in the ablation group and the proportion of patients with an atrial fibrillation burden of <5% at 3-12 months was 8/15 (53%). The left ventricular ejection fraction increased during follow-up in the ablation group compared with the control group (from 53.7 ± 8.6 to 58.8 ± 6.5%, P = 0.003), combined with a reduction in the left atrial area (from 29.2 ± 5.5 to 27.2 ± 6.3 cm(2), P = 0.002). The physical working capacity increased in the ablation group compared with the control group (from 94 ± 21.4 to 102.9 ± 14.4%, P = 0.011). The subjective physical and mental capacity scale also improved during follow-up in the ablation group, but not in the control group (P = 0.003 and 0.018, respectively).

CONCLUSIONS

Total endoscopic ablation in patients with long-standing persistent atrial fibrillation significantly reduced atrial fibrillation burden 12 months after intervention compared with controls. The left ventricular function, physical working capacity and subjective physical and mental health were improved. These results need to be confirmed in larger randomized trials.

CLINICALTRIALSGOV IDENTIFIER

NCT00940056.

The totally thoracoscopic left atrial maze procedure for the treatment of atrial fibrillation

The totally thoracoscopic left atrial maze (TT-maze) is a recent, minimally invasive surgical procedure for the treatment of atrial fibrillation, with promising results in terms of freedom from atrial fibrillation. The TT-maze consists of a bilateral, epicardial pulmonary vein isolation with the creation of a box using radiofrequency and exclusion of the left atrial appendage (LAA). In addition, the box is connected with the base of the LAA and furthermore with the mitral annulus with the so-called trigonum line. In this report, we describe our surgical approach and short-term results.

Novel Percutaneous Epicardial Autonomic Modulation in the Canine for Atrial Fibrillation: Results of an Efficacy and Safety Study

BACKGROUND

Endocardial ablation of atrial ganglionated plexi (GP) has been described for treatment of atrial fibrillation (AF). Our objective in this study was to develop percutaneous epicardial GP ablation in a canine model using novel energy sources and catheters.

METHODS

Phase 1: The efficacy of several modalities to ablate the GP was tested in an open chest canine model (n = 10). Phase 2: Percutaneous epicardial ablation of GP was done in six dogs using the most efficacious modality identified in phase 1 using two novel catheters.

RESULTS

Phase 1: Direct current (DC) in varying doses (blocking [7-12 μA], electroporation [300-500 μA], ablation [3,000-7,500 μA]), radiofrequency ablation (25-50 W), ultrasound (1.5 MHz), and alcohol (2-5 mL) injection were successful at 0/8, 4/12, 5/7, 3/8, 1/5, and 5/7 GP sites. DC (500-5,000 μA) along with alcohol irrigation was tested in phase 2. Phase 2: Percutaneous epicardial ablation of the right atrium, oblique sinus, vein of Marshall, and transverse sinus GP was successful in 5/6 dogs. One dog died of ventricular fibrillation during DC ablation at 5,000 μA. Programmed stimulation induced AF in six dogs, preablation and no atrial arrhythmia in three, flutter in one, and AF in one postablation. Heart rate, blood pressure, effective atrial refractory period, and local atrial electrogram amplitude did not change significantly postablation. Microscopic examination showed elimination of GP, and minimal injury to atrial myocardium.

CONCLUSION

Percutaneous epicardial ablation of GP using DC and novel catheters is safe and feasible and may be used as an adjunct to pulmonary vein isolation in the treatment of AF in order to minimize additional atrial myocardial ablation.

Epicardial thoracoscopic ablation versus endocardial catheter ablation for management of atrial fibrillation: a systematic review and meta-analysis

OBJECTIVES

In the treatment of patients with atrial fibrillation (AF), the efficacy and safety of epicardial thoracoscopic ablation (TA) versus endocardial catheter ablation (CA) using radiofrequency energy remains unclear. This meta-analysis was performed to assess the efficacy and safety of each ablation technique using a pooled comparative analysis.

METHODS

Studies comparing the efficacy and safety of TA and CA were identified by searching electronic databases. Those that reported patients' freedom from atrial arrhythmia and significant side effects were included.

RESULTS

Three randomized controlled trials (RCTs) and two retrospective cohort studies with a total of 587 patients were included in the meta-analysis (273 patients underwent TA and 314 patients underwent CA). The proportion of patients who were free of atrial arrhythmia without antiarrhythmic drugs during 12 months of follow-up was significantly higher after TA than after CA in the RCTs [P < 0.001; relative risk (RR), 1.77; 95% confidence interval (CI), 1.34-2.32] and in the retrospective cohort studies (P = 0.010; RR, 1.68; 95% CI, 1.12-2.51). The incidence of significant side effects during the post-procedural period was significantly higher in the TA group than in the CA group in both the RCT (P = 0.007; RR, 7.23; 95% CI, 1.71-30.49) and the retrospective cohort studies (P = 0.020; RR, 4.39; 95% CI, 1.33-14.46).

CONCLUSIONS

Based on the available data, TA was found to be more effective than CA in achieving freedom from atrial arrhythmia; however, TA had a higher rate of immediate post-procedural complications than CA.

Outcome of stand-alone thoracoscopic epicardial left atrial posterior box isolation with bipolar radiofrequency energy for longstanding persistent atrial fibrillation

Introduction

Catheter ablation of longstanding (> 1 year) persistent atrial fibrillation (AF) is associated with poor outcome. This might be due to remodelling and fibrosis formation, mainly located in the posterior left atrial (LA) wall. Therefore, we adopted a thoracoscopic epicardial box isolation of the posterior left atrium using bipolar RF energy with intraoperative testing of conduction block.

Methods and results

Bilateral thoracoscopic box isolation was performed with a bipolar RF clamp. Entrance block was defined as absence of a conducted electrogram within the box, while exit block was confirmed by pacing at 10.0 V/2 ms. Ablation outcome was evaluated after 3, 6, 12 and 24 months with 12-lead ECGs and 24-hour Holter recordings.

Twenty-five consecutive patients were included (58 ± 7 years, persistent AF duration 1.8 ± 0.9 years). Entrance block was achieved in all patients and exit block confirmed if sinus rhythm was achieved. After 17 ± 7 months, 76 % of the patients (n = 19) were free of AF recurrence. One patient died within 1 month and was considered an ablation failure. Four patients with AF recurrences regained sinus rhythm with additional catheter ablation or antiarrhythmic drugs.

Conclusions

Treatment of longstanding persistent AF with thoracoscopic epicardial LA posterior box isolation using bipolar RF energy with intraoperative testing of conduction block is feasible and highly effective.

Clinical Significance of Additional Ablation of Atrial Premature Beats after Catheter Ablation for Atrial Fibrillation

PURPOSE

The clinical significance of post-procedural atrial premature beats immediately after catheter ablation for atrial fibrillation (AF) has not been clearly determined. We hypothesized that the provocation of immediate recurrence of atrial premature beats (IRAPB) and additional ablation improves the clinical outcome of AF ablation.

MATERIALS AND METHODS

We enrolled 200 patients with AF (76.5% males; 57.4±11.1 years old; 64.3% paroxysmal AF) who underwent catheter ablation. Post-procedure IRAPB was defined as frequent atrial premature beats (≥6/min) under isoproterenol infusion (5 μg/min), monitored for 10 min after internal cardioversion, and we ablated mappable IRAPBs. Post-procedural IRAPB provocations were conducted in 100 patients. We compared the patients who showed IRAPB with those who did not. We also compared the IRAPB provocation group with 100 age-, sex-, and AF-type-matched patients who completed ablation without provocation (No-Test group).

RESULTS

1) Among the post-procedural IRAPB provocation group, 33% showed IRAPB and required additional ablation with a longer procedure time (p=0.001) than those without IRAPB, without increasing the complication rate. 2) During 18.0±6.6 months of follow-up, the patients who showed IRAPB had a worse clinical recurrence rate than those who did not (27.3% vs. 9.0%; p=0.016), in spite of additional IRAPB ablation. 3) However, the clinical recurrence rate was significantly lower in the IRAPB provocation group (15.0%) than in the No-Test group (28.0%; p=0.025) without lengthening of the procedure time or raising complication rate.

CONCLUSION

The presence of post-procedural IRAPB was associated with a higher recurrence rate after AF ablation. However, IRAPB provocation and additional ablation might facilitate a better clinical outcome. A further prospective randomized study is warranted.

Surgical Treatment of Atrial Fibrillation

Atrial fibrillation (AF) is the most common chronic arrhythmia in the adult population. Ablation lines have largely replaced the historical and challenging cut and sew techniques. Surgical ablation of AF is commonly performed in cases with other indications for cardiac surgery and less commonly as a stand-alone therapy. Pulmonary vein isolation is the cornerstone of this procedure. Extended left atrial ablation lines may increase efficacy in cases with longstanding persistent or permanent AF. Additional efficacy by adding right atrial ablation is controversial but is often performed in cases undergoing right atrial or atrial septal surgery. Left atrial volume reduction is recommended in cases with large left atria and AF undergoing another cardiac surgery. Arrhythmia recurrence is not uncommon after surgical ablation of AF and varies among studies due to heterogeneity in patient population, lesion set and endpoints. Freedom from AF recurrence was 65-87% at 12 months and 58-70% at 2 years follow-up. Long-term monitoring is recommended due to an increased prevalence of asymptomatic recurrences. The strongest predictors of AF recurrence are longstanding or persistent AF and a large left atrium. The most common mechanisms of recurrence are pulmonary vein reconnection, nonpulmonary vein triggers, and gaps in the ablation lines. About 20% of atrial tachyarrhythmia recurrences are atrial flutter or atrial tachycardia. There are not enough data in the surgical literature to support withdrawal of anticoagulation after surgical AF ablation. Patients selected for stand-alone surgical ablation usually have low risk profiles and low postoperative mortality rates (0.2%).

Patients with minimal atrial fibrillation events should not undergo concomitant atrial ablation during open heart procedures

Several randomized controlled trials and meta-analyses have demonstrated improved freedom from atrial fibrillation with intraoperative atrial ablation. However, the increased bypass time and the risk for ablation-related complications should be weighed against the benefits in the decision-making. It is important to establish reasonable criteria to define candidates for surgical ablation. Furthermore, the efficacy and short- and long-term risks related to surgical ablation need to be considered. This article reviews the data on surgical ablation of atrial fibrillation as it pertains to these important issues. As shown the evidence does not support surgical ablation at the time of coronary artery bypass graft in some patients.

Total endoscopic ablation of atrial fibrillation

Total endoscopic ablation of atrial fibrillation is a treatment option in symptomatic patients after unsuccessful catheter ablation or when catheter ablation is considered inappropriate. We describe a technique of endoscopic ablation of the left atrium using temperature-controlled unipolar or bipolar radiofrequency. A left atrial box lesion encircling the pulmonary veins is created using three ports in the right hemithorax. The technical aspects and preliminary results of the procedure are discussed.

Elimination Of Triggers Without An Additional Substrate Modification Is Not Sufficient In Patients With Persistent Atrial Fibrillation

Atrial fibrillation (AF) is a multifactorial disease with complex pathophysiology. Although restoring sinus rhythm delays the progression of atrial remodeling, non-pharmacologic intervention, such as radiofrequency catheter ablation (RFCA), should be done based on the background pathophysiology of the disease. While circumferential pulmonary vein isolation (CPVI) has been known to be the cornerstone of AF catheter ablation, a clinical recurrence rate after CPVI is high in patients with persistent AF (PeAF). Step-wise linear ablation, complex fractionate atrial electrogram (CFAE)-guided ablation, rotor ablation, ganglionate plexus ablation, and left atrial appendage isolation may improve the ablation success rate after CPVI. But, there are still substantial AF recurrences after such liberal atrial substrate ablation, and current ablation techniques regarding substrate modification still have limitations. Therefore, more understanding about AF pathophysiology and early precise intervention may improve clinical outcome of AF management. Keeping in mind "more touch, more scar," operators should generate most efficient substrate modification to achieve better long-term clinical outcome.

Surgical options in atrial fibrillation

Atrial fibrillation (AF) is not benign and its prevalence is increasing. The two main goals in management of atrial fibrillation are to optimize hemodynamics through rate or rhythm control and to prevent systemic thrombo-embolism. To date, these two goals are still sub-optimally achieved, raising the need for alternative methods and strategies both pharmacologically and through interventions. In this review, we discuss surgical strategies of achieving both goals with insights on the evolution and potential future of these strategies.

Cardiac Autonomic Denervation for Ablation of Atrial Fibrillation

The influence of the autonomic nervous system (ANS) on triggering and perpetuation of atrial fibrillation (AF) is well established. Ganglionated plexi (GP) ablation achieves autonomic denervation by affecting both the parasympathetic and sympathetic components of the ANS. GP ablation can be accomplished endocardially or epicardially, i.e. during the maze procedure or thoracoscopic approaches. Recent evidence indicates that anatomic GP ablation at relevant atrial sites appears to be safe and improves the results of pulmonary vein isolation in patients with paroxysmal and persistent AF.

Atrial Fibrillation Ablation by the Epicardial Approach

Catheter ablation is an effective treatment for atrial fibrillation (AF). However, over long-term follow-up, it is becoming clear that AF often recurs and repeat ablation is required. With the goal of improving efficacy, particularly in those patients with risk factors for poor outcomes using a standard endocardial ablation technique, surgical epicardial ablation has emerged as an alternative methodology. Since its advent in the 1980s, surgical ablation techniques have continued to evolve. New ablation tools make a minimally invasive surgical approach possible. And most recently, we have seen the development of a hybrid (epicardial and endocardial) approach to AF ablation, which can draw upon the advantages of both options.

A systematic review of surgical ablation versus catheter ablation for atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is an increasingly prevalent condition in the ageing population, with significantly associated morbidity and mortality. Surgical and catheter ablative strategies both aim to reduce mortality and morbidity through freedom from AF. This review consolidates all currently available comparative data to evaluate these two interventions.

METHODS

A systematic search was conducted across MEDLINE, PubMed, Embase, Cochrane Central Register of Controlled Trials and the Cochrane Database of Systematic Reviews from January 2000 until August 2013. All studies were critically appraised and only those directly comparing surgical and catheter ablation were included.

RESULTS

Seven studies were deemed suitable for analysis according to the inclusion criteria. Freedom from AF was significantly higher in the surgical ablation group versus the catheter ablation group at 6-month, 12-month and study endpoint follow-up periods. Subgroup analysis demonstrated similar trends, with higher freedom from AF in the surgical ablation group for paroxysmal AF patients. The incidence of pacemaker implantation was higher, while no difference in stroke or cardiac tamponade was demonstrated for the surgical versus catheter ablation groups.

CONCLUSIONS

Current evidence suggests that epicardial ablative strategies are associated with higher freedom from AF, higher pacemaker implantation rates and comparable neurological complications and cardiac tamponade incidence to catheter ablative treatment. Other complications and risks were poorly reported, which warrants further randomized controlled trials (RCTs) of adequate power and follow-up duration.

The Role of Renal Sympathetic Denervation in Atrial Fibrillation

Endocardial catheter ablation is a widely used alternative for the treatment of atrial fibrillation (AF). Despite technical improvements, and increased understanding of mechanism, and acquired technical experience over many years, the results are not yet optimal. This results in an ongoing search for new therapeutic approaches. Because cardiac sympathetic drive is potentially responsible for triggering and sustaining AF, modulation of sympathetic tone has been proposed as a viable treatment objective. The early attempts to test this concept were limited by nature=highly intrusive techniques but new approaches and targets have been recently introduced. Specifically, renal nerve ablation has been introduced and the first attempts to employ this technique for treatment of cardiac arrhythmias give as a promise of new therapeutic avenues in near future. This review focuses on the possible role of renal denervation in treatment of atrial fibrillation, the contemporary evidence supporting this approach, and the ongoing trials to establish its therapeutic role.

Surgical treatment of atrial fibrillation: an updated review

The first Cox-maze procedure was performed in 1987, demonstrating the feasibility of a non-pharmacological treatment for atrial fibrillation (AF). Since then, surgery for AF has changed over time, in parallel with technological advances. Replacement of surgical incisions with linear ablation lines made a previously cumbersome procedure accessible to most surgeons, without compromising success. On the other hand, new ablation technologies paved the way for the development of minimally invasive surgery, which may potentially extend the scope of surgery to patients who would otherwise be deemed unsuitable. Nonetheless, literature on minimally invasive surgery is still scarce and randomized clinical trials currently under way are expected to shed light on some controversial issues. Moreover, successful AF treatment will probably rely on close collaboration between surgery and electrophysiology. Indeed, the hybrid procedure, though still in its very beginning, seems to combine the best of catheter and surgical ablation. However, further studies are warranted to determine the effectiveness of this promising strategy, especially in patients with persistent and longstanding persistent AF. Better understanding of AF pathophysiology as well as more accurate preoperative localization of AF triggers will bring about the possibility of tailoring specific lesion sets and ablation modalities to individual patients. This, in turn, will increase recovery and maintenance of sinus rhythm, with significant benefits in long-term outcomes.

Hybrid surgical and catheter treatment for atrial fibrillation

Advances in surgery for atrial fibrillation from cut and sew technique to thoracoscopy and new energy source have enabled minimally invasive approach which avoids median sternotomy and cardiopulmonary bypass. However, minimally invasive approach is unable to match the outcome of classic surgical technique due to difficulty in creating some of linear ablation lines. Hybrid procedure using catheter mapping and ablation in addition to minimally invasive surgical ablation has gained interest to combine the advantages of both procedures. No large study has been conducted to date comparing this new technique to other existing treatments. The aim of this paper is to review the data on hybrid procedure for atrial fibrillation and assess its early outcome and efficacy.

Long-term results of a minimally invasive surgical pulmonary vein isolation and ganglionic plexi ablation for atrial fibrillation

Background

Ganglionated plexi (GP) ablation has been become an adjunct to pulmonary vein isolation (PVI). This study describes the long-term results of minimally invasive surgical PVI, ablation of GPs, and exclusion of the left atrial appendage for atrial fibrillation (AF).

Methods

Long-term follow-up of 55 months was performed in 139 consecutive patients (age 58.3±20.8 years) with symptomatic, drug-refractory lone AF who underwent minimally invasive surgical PVI, GPs ablation, and exclusion of the left atrial appendage. Success was defined as freedom from AF, atrial flutter, or atrial tachycardia off antiarrhythmic drugs.

Results

AF was paroxysmal in 77.7%, persistent in 12.2% and long-standing persistent in 10.1%. Single-procedure success rate was 71.7%, 59.4% and 46.6% at 12, 24 and 60 months respectively. Single-procedure success rate was 72.9%, 62.6% and 51.8% for paroxysmal AF, 64.7%, 35.3%, and 28.2% for persistent AF, 71.4%, 64.3% and 28.6% for long-standing persistent AF at 12, 24 and 60 months respectively. Duration of AF>24 months (hazard ratio [HR]: 3.09, 95% confidence interval [CI]: 1.51 to 6.32; p = 0.002), left atrial diameter≥40 mm (HR: 4.03, 95% CI: 1.88 to 8.65; p<0.001), early recurrence of AF (HR: 4.66, 95% CI: 2.25 to 9.63; p<0.001) independently predicted long-term recurrence of AF. There was no procedure-related death. One patient converted to median sternotomy because of uncontrolled bleeding. Two patients underwent perioperative cerebrovascular events.

Conclusions

At nearly 5-year of clinical follow-up, single-procedure success rate of minimally invasive surgical PVI with GP ablation was 51.8% for paroxysmal AF, 28.2% for persistent AF, 28.6% for long-standing persistent AF after initial procedure. Patients with AF duration≤24 months, left atrial diameter<40 mm and no early recurrence of AF, had favorable outcomes.

Quantitative magnetic resonance imaging analysis of the relationship between contact force and left atrial scar formation after catheter ablation of atrial fibrillation

BACKGROUND

Catheter contact force (CF) is an important determinant of radiofrequency (RF) lesion quality during pulmonary vein isolation (PVI). Late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) allows good visualization of ablation lesions.

OBJECTIVE

This study describes a new technique to examine the relationship between CF during RF delivery and LGE signal intensity (SI) following PVI.

METHODS

Six patients underwent PVI for paroxysmal AF using a CF-sensing catheter and following preprocedural MRI. During ablation, CF-time integral (FTI) and position was documented for each RF application. All patients underwent repeat LGE MRI 3 months later. The LGE SIs were projected onto a MRI-derived 3-dimensional left atrial (LA) shell and a CF map was generated on the same shell. The entire LA surface was divided into 5 mm(2) segments. Force and LGE maps were fused and compared for each 5 mm(2) zone. An effective lesion was defined when MRI-defined scar occupied >90% of a 5 mm(2) analysis zone.

RESULTS

Acute PVI was achieved in 100%. Two hundred sixty-eight RF lesions were tagged on the LA shells and given a lesion-specific FTI. Increasing FTI correlated with increased LGE SI, which was greater when the FTI was > 1,200 gs. Below an FTI of 1,200 gs, an increment in the FTI resulted in only a small increment in scar, whereas above 1,200 gs an increment in the FTI resulted in a large change of scar.

CONCLUSION

There is a correlation between FTI and LGE SI in MRI following AF ablation. Real-time FTI maps are feasible and may prevent inadequate lesion formation.

Surgical Minimally Invasive Pulmonary Vein Isolation for Lone Atrial Fibrillation

Objective

Minimally invasive surgical pulmonary vein isolation (SMI-PVI) is an emerging therapy for the treatment of symptomatic drug-refractory atrial fibrillation (AF). Nevertheless, the midterm and long-term results of SMI-PVI remain unknown. The aim of this retrospective multicenter study was to report on midterm efficacy and safety of SMI-PVI.

Methods

The study design was retrospective, multicentric, and observational. From July 2005 to November 2011, a total of 86 patients with drug-refractory paroxysmal or persistent AF underwent SMI-PVI in three centers. Patients were eligible for SMI-PVI if they had symptomatic, drug-refractory AF or after failed transcatheter pulmonary vein isolation. Success was defined as absence of AF on 24- or 96-hour Holter monitoring during follow-up, in the absence of antiarrhythmic drugs (AADs).

Results

The mean ± SD age was 54 ± 11 years, and 78% were men. The median AF duration was 30 months (range, 2–203); paroxysmal AF was present in 86% of the patients, persistent in 14%. Fifteen patients (17%) underwent previous transcatheter ablations. After a median follow-up of 24 months (range, 6–78), 72% of all patients were free from atrial arrhythmias without the use of AADs. With AADs, this was 83%. Major perioperative adverse events occurred in 7 patients (8%).

Conclusions

This retrospective multicenter study shows that SMI-PVI is effective at a median follow-up of 24 months for the treatment of mostly paroxysmal drug-refractory AF. Perioperative adverse events do remain a point of caution.