Isolating the entire posterior left atrium improves surgical outcomes after the Cox maze procedure

Clinical impact of cryoballoon posterior wall isolation using the cross-over technique in persistent atrial fibrillation

BACKGROUND AND AIMS

Successful left atrial posterior wall isolation (LAPWI) using only the cryoballoon (CB) is technically challenging for the treatment of atrial fibrillation (AF). This study aimed to evaluate the efficacy of the cross-over technique, wherein an overlapped ablation is performed by placing the CB from both directions in contact with the LAPW.

METHODS

This was a single-center, retrospective, observational study of 194 consecutive patients with persistent atrial fibrillation (PerAF) who underwent a first-time procedure of pulmonary vein isolation (PVI) + PWI (108 patients) or PVI-only (86 patients) using the CB. The cross-over technique was applied in all LAPWI.

RESULTS

For ablation of the LA roof and bottom, respectively, a mean of 8.6 ± 1.0 (right to left [R→L] 4.3 ± 1.1 and left to right [L→R] 4.3 ± 1.1) and 9.1 ± 1.2 (R→L 4.6 ± 1.6 and L→R 4.5 ± 1.2) CB applications were delivered. LAPW was successfully isolated solely using the CB in 99.1% of patients. Although the PVI + PWI group had significantly longer procedure time, no severe adverse events were observed in either group. During a median follow-up of 19 months, freedom from recurrence of all atrial tachyarrhythmias was achieved in 93.5% of the PVI + PWI group and 72.9% of the PVI-only group (p = .011).

CONCLUSIONS

LAPWI performed solely with the CB using the cross-over technique is feasibly, safe, and was independently associated with a significantly higher freedom from recurrence of atrial tachyarrhythmias compared with PVI alone in patients with PerAF.

First-in-Man Use of Intraoperative Electrophysiological Mapping to Evaluate the Efficacy of the EnCompass Clamp During a Cox-IV Maze Procedure

This case report describes the first-in-man use of intraoperative electrophysiological (EP) mapping to evaluate the efficacy of the EnCompass clamp (AtriCure, Inc., Mason, OH) during a Cox-IV Maze procedure. A 53-year-old male with paroxysmal atrial fibrillation and severe mitral valve regurgitation underwent mitral valve repair with concomitant surgical ablation for atrial fibrillation. Intraoperative 3D EP mapping was performed using the Abbott EnSite Precision system (Abbott Inc., Chicago, IL) before ablation, after initial radiofrequency ablation with the AtriCure EnCompass clamp, and after the full Cox-IV Maze procedure was completed. The pre-ablation map showed approximately 80-85% high voltage areas in the posterior left atrial wall. Initial ablation with the EnCompass clamp reduced high voltage areas to 30-35%. The final map following the Cox-IV Maze procedure demonstrated near-complete electrical silence, with only 5-10% of the atrial surface retaining high voltage activity. This represents an estimated 88% reduction in high-voltage areas from baseline. The patient had an uncomplicated postoperative course apart from one episode of postoperative atrial fibrillation requiring direct current (DC) cardioversion. This case demonstrates the utility of intraoperative EP mapping in guiding and confirming the efficacy of surgical ablation procedures, as well as the effectiveness of combining the EnCompass clamp with a full Cox-IV Maze in achieving comprehensive atrial electrical isolation. The EnCompass clamp can be used for ablations with a beating heart, thus reducing the aortic cross-clamp time and therefore minimizing the total myocardial ischemia time.

Catheter ablation using pulmonary vein isolation with versus without left atrial posterior wall isolation for persistent atrial fibrillation: an updated systematic review and meta-analysis

BACKGROUND

Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation of atrial fibrillation (AF); however, the results are suboptimal for persistent AF. The left atrial posterior wall (LAPW) is thought to be a major additional area in initiation and perpetuation of persistent AF. Therefore, adjunctive ablation of the posterior wall may reduce AF recurrence in patients with persistent AF.

OBJECTIVE

The objective of this study was to compare outcomes of catheter ablation in patients with persistent AF using PVI alone versus a combination of PVI and LAPW isolation.

METHODS

Literature search was conducted in PubMed, PubMed Central, Scopus, and Embase since inception to February 2023. Screening of studies was done via Covidence software. Risk of bias assessment was done using appropriate tools. Data extraction and a narrative synthesis were carried out accordingly.

RESULTS

Ten studies were included, of which five were randomized controlled trials. PVI with LAPW ablation group had significantly lower recurrence of overall atrial tachyarrhythmia (OR 0.47, CI 0.32-0.70) and AF (OR 0.39, CI 0.23-0.69). In sensitivity analysis, freedom from atrial arrhythmias was noted to be significantly higher in the PVI with LAPW ablation group (OR 2.22, CI 1.36-3.64). However, there was no significant difference in occurrence of atrial flutter (OR 1.36, CI 0.86-2.14) or with periprocedural adverse events (OR 1.10, CI 0.60-1.99).

CONCLUSION

LAPW ablation, in addition to PVI, significantly improves the rates of arrhythmia freedom and reduces the recurrence of overall atrial tachyarrhythmia. There was no significant difference in atrial flutter or periprocedural adverse events.

Efficacy and safety of hybrid epicardial and endocardial ablation versus endocardial ablation in patients with persistent and longstanding persistent atrial fibrillation: a randomised, controlled trial

Background

Endocardial catheter ablation (CA) has limited long-term benefit for persistent and longstanding persistent atrial fibrillation (PersAF/LSPAF). We hypothesized hybrid epicardial-endocardial ablation (HA) would have superior effectiveness compared to CA, including repeat (rCA), in PersAF/LSPAF.

Methods

CEASE-AF (NCT02695277) is a prospective, multi-center, randomized controlled trial. Nine hospitals in Poland, Czech Republic, Germany, United Kingdom, and the Netherlands enrolled eligible participants with symptomatic, drug refractory PersAF and left atrial diameter (LAD) > 4.0 cm or LSPAF. Randomization was 2:1 to HA or CA by an independent statistician and stratified by site. Treatment assignments were masked to the core rhythm monitoring laboratory. For HA, pulmonary veins (PV) and left posterior atrial wall were isolated with thoracoscopic epicardial ablation including left atrial appendage exclusion. Endocardial touch-up ablation was performed 91-180 days post-index procedure. For CA, endocardial PV isolation and optional substrate ablation were performed. rCA was permitted between days 91-180. Primary effectiveness was freedom from AF/atrial flutter/atrial tachycardia >30-s through 12-months absent class I/III anti-arrhythmic drugs except those not exceeding previously failed doses. It was assessed in the modified intention-to-treat (mITT) population who had the index procedure and follow-up data. Major complications were assessed in the ITT population who had the index procedure. Thirty-six month follow-up continues.

Findings

Enrollment began November 20, 2015 and ended May 22, 2020. In 154 ITT patients (102 HA; 52 CA), 75% were male, mean age was 60.7 ± 7.9 years, mean LAD was 4.7 ± 0.4 cm, and 81% had PersAF. Primary effectiveness was 71.6% (68/95) in HA versus 39.2% (20/51) in CA (absolute benefit increase: 32.4% [95% CI 14.3%-48.0%], p < 0.001). Major complications through 30-days after index procedures plus 30-days after second stage/rCA were similar (HA: 7.8% [8/102] versus CA: 5.8% [3/52], p = 0.75).

Interpretation

HA had superior effectiveness compared to CA/rCA in PersAF/LSPAF without significant procedural risk increase.

Funding

AtriCure, Inc.

Efficacy of a Novel Bipolar Radiofrequency Clamp: An Acute Porcine Model

OBJECTIVE

Expert consensus guidelines recommend surgical ablation (SA) for patients with symptomatic atrial fibrillation (AF), but less than half of patients with AF undergoing cardiac procedures receive concomitant SA. Complete isolation of the left atrial posterior wall (LAPW) has been shown to be the most critical part of the Cox maze procedure. The purpose of this study was to investigate the performance of a novel radiofrequency (RF) bipolar device, EnCompass™ (AtriCure, Inc., Mason, OH, USA), designed to isolate the LAPW in a single application.

METHODS

Five adult pigs underwent SA in a beating heart model. After a single ablation, the heart was arrested, explanted, and stained with triphenyl-tetrazolium-chloride for histological assessment. Each lesion was sectioned, and the ablation depth, muscle, and fat thickness were determined. The lesion width, energy delivery, and ablation times were compared with those from a reference RF clamp (Synergy™, AtriCure).

RESULTS

Transmurality was documented in 100% of lesions (5 of 5) and cross sections (160 of 160). Electrical isolation was documented in every instance. There was no evidence of clot, charring, or pulmonary vein stenosis. Compared with the reference clamp, the lesions created by the EnCompass™ clamp were 1.5 times wider on average. The average energy delivered was 5 times higher over a duration that was 4.5 times longer due to the increased volume of tissue ablated.

CONCLUSIONS

The EnCompass™ clamp reproducibly created transmural isolation of the LAPW with a single application. This may allow for simplification of the SA strategy and increased adoption of AF treatment during concomitant surgery.

A Chronicle of Hybrid Atrial Fibrillation Ablation Therapy: From Cox Maze to Convergent

The burden of AF is increasing in prevalence and healthcare resource usage in the UK and worldwide. It can result in impaired quality of life for affected patients, as well as increased risk of stroke, heart failure and mortality. A holistic, integrated approach to AF management is recommended, which may include a focus on reducing risk factors and on medical management with anticoagulation and anti-arrhythmic drugs. There are also various ablation strategies that may be considered when anti-arrhythmic drugs fail to alleviate symptoms and reduce AF burden. These ablation techniques range from standalone percutaneous endocardial catheter ablation to open surgical ablation procedures concomitant with cardiac surgery. More recently, hybrid ablation that combines aspects of both surgical and electrophysiologically targeted ablation has been described. This article reviews the evolution of ablation strategies, beginning with the origin of the Cox maze IV procedure and continuing to the recent hybrid convergent approach, and provides a summary of the associated outcomes.

The long-term outcomes and durability of the Cox-Maze IV procedure for atrial fibrillation

OBJECTIVE

Surgical ablation of atrial fibrillation (AF) is indicated both in patients with AF undergoing concomitant cardiac surgery and in those who have not responded to medical and/or catheter-based ablation therapy. This study examined our long-term outcomes following the Cox-Maze IV procedure (CMP-IV).

METHODS

Between May 2003 and March 2018, 853 patients underwent either biatrial CMP-IV (n = 765) or a left-sided CMP-IV (n = 88) lesion set with complete isolation of the posterior left atrium. Freedom from atrial tachyarrhythmia (ATA) was assessed for up to 10 years. Rhythm outcomes were compared in multiple subgroups. Predictors of recurrence were determined using Fine-Gray regression, allowing for death as the competing risk.

RESULTS

The majority of patients (513/853, 60%) had nonparoxysmal AF. Twenty-four percent of patients (201/853) had not responded to at least 1 catheter-based ablation. Prolonged monitoring was used in 76% (647/853) of patients during their follow-up. Freedom from ATA was 92% (552/598), 84% (213/253), and 77% (67/87) at 1, 5, and 10 years, respectively. By competing risk analysis, incidence of first ATA recurrence was 11%, 23%, and 35% at 1, 5, and 10 years, respectively. On Fine-Gray regression, age, peripheral vascular disease, nonparoxysmal AF, left atrial size, early postoperative ATAs, and absence of sinus rhythm at discharge were the predictors of first ATA recurrence over 10 years of follow-up.

CONCLUSIONS

The CMP-IV had an excellent long-term efficacy at maintaining sinus rhythm. At late follow-up, the results of the CMP-IV remained superior to those reported for catheter ablation and other forms of surgical ablation for AF. Age, left atrial size, and nonparoxysmal AF were the most relevant predictors of late recurrence.

Hybrid Convergent Procedure for the Treatment of Persistent and Long-standing Persistent Atrial Fibrillation

Recent advances have been made in AF treatment, including the role of early rhythm control and landmark clinical trials using ablation therapy. However, some treatment gaps remain, including the creation of durable lesions outside the pulmonary veins and effective treatment of longstanding persistent AF. A novel epicardial-endocardial ablation approach - the hybrid convergent procedure - was developed to combine surgical and catheter ablation techniques into a collaborative, multidisciplinary approach to managing AF. In this review, the authors discuss recently published data on hybrid convergent ablation, including results of the CONVERGE clinical trial, in the context of current challenges to treatment of persistent and long-standing persistent AF. The review also aims to provide perspective on outstanding questions and future directions in this area.

Pulmonary vein and left atrial posterior wall isolation for the treatment of atrial fibrillation: Comparable outcomes for adults with congenital heart disease

INTRODUCTION

Optimal treatment strategies for ACHD with AF are unknown. This study sought to assess outcomes of pulmonary vein isolation (PVI) ± left atrial (LA), posterior wall isolation (PWI) for adults with congenital heart disease (ACHD), and atrial fibrillation (AF).

METHODS

A retrospective review of all cryoballoon (CB) PVI ± PWI procedures at a single center over a 3-year period were performed. Clinical characteristics and outcomes for patients with and without ACHD were compared. The primary outcome was the occurrence of atrial tachyarrhythmia at 12-months postablation after a 90-day blanking period.

RESULTS

Three-hundred and sixteen patients (mean: 63 ± 12 years, [63% male]) underwent CB PVI ± PWI during the study, including 31 (10%) ACHD (simple 35%, moderate 39% complex 26%; nonparoxysmal AF in 52%). ACHD was younger (51 vs. 64 years; p < .001) with a lower CHADS₂ DS₂ -VASc score (1.2 vs. 2.1; p = .001) but had a greater LA diameter (4.9 vs. 4.0 cm; p < .001) and a number of prior cardioversions (0.9 vs. 0.4; p < .001) versus controls. 12-month freedom from recurrent AF was similar for ACHD and controls (76% vs. 80%; p = .6) and remained nonsignificant in multivariate analysis (hazard ratio: 1.8, 95% confidence interval: 0.7-5.1; p = .22). At 12-months postablation, 75% of ACHD versus 93% of control patients were off antiarrhythmic drug therapy (p = .07).

CONCLUSION

This study demonstrates younger age and lower conventional stroke risk, yet clinically advanced AF for ACHD relative to controls. CB PVI ± PWI was an effective strategy for the treatment of AF among all forms of ACHD with similar 12-month outcomes as compared to controls.

Surgical Atrial Fibrillation Ablation With and Without Left Atrium Reduction for Patients Scheduled for Mitral Valve Surgery: A Prospective Randomised Study

BACKGROUND

The influence of left atrium (LA) enlargement on atrial arrhythmia recurrence (AAR) after surgical ablation in patients with mitral valve (MV) disease remains unresolved.

OBJECTIVE

Left atrial size is critical to the success of concomitant atrial fibrillation (AF) ablation in patients scheduled for MV surgery. However, a large LA should not be a limiting factor when evaluating surgical candidates with AF if they receive appropriate treatment during concomitant ablation. This randomised study assessed whether adding LA reduction (LAR) to the maze procedure for MV surgery patients can improve freedom from AAR.

METHODS

From September 2014 to September 2017, 140 patients were randomly assigned into two groups. The maze group underwent MV surgery with concomitant surgical AF ablation (n=70). The maze + LA reduction group underwent MV surgery with concomitant AF ablation and LA reduction procedure (n=70). Rhythm outcomes were estimated by Holter monitoring, according to Heart Rhythm Society guidelines.

RESULTS

The concomitant LA reduction procedure did not increase early mortality and complications rates. Significant differences in freedom from AAR were observed at 24 months (maze, 78.4%; maze + LAR group, 92.3%; p=0.025). A significant difference in LA volume was detected at discharge (p<0.0001); however, it was not significantly different at 24 months (p=0.182).

CONCLUSIONS

Adding LA reduction to the maze procedure led to improvements in freedom from AAR for patients with AF and LA enlargement scheduled for MV surgery. A concomitant LA reduction procedure did not increase mortality and perioperative risk.

The Arrhythmic Substrate for Atrial Fibrillation in Patients with Mitral Regurgitation

Objective

Patients with severe mitral regurgitation commonly develop atrial fibrillation. The precise mechanisms of this relationship remain unknown. The objective of this study was to apply noninvasive electrocardiographic imaging of the atria during sinus rhythm to identify changes in atrial electrophysiology that may contribute to development of atrial fibrillation in patients with severe mitral regurgitation referred for mitral valve surgery.

Methods

Twenty subjects (9 atrial fibrillation and mitral regurgitation, 11 mitral regurgitation alone) underwent electrocardiographic imaging. Biatrial electrophysiology was imaged with activation maps in sinus rhythm. The reconstructed unipolar electrograms were analyzed for voltage amplitude, number of deflections and conduction heterogeneity. In subjects with mitral regurgitation, left atrial biopsies were obtained at the time of surgery. Results: Subjects with history of atrial fibrillation demonstrated prolonged left atrial conduction times (110±25 ms vs. mitral regurgitation alone (85±21), p=0.025); right atrial conduction times were unaffected. Variable patterns of conduction slowing were imaged in the left atria of most subjects, but those with prior history of atrial fibrillation had more complex patterns of conduction slowing or unidirectional block. The presence of atrial fibrillation was not associated with the extent of fibrosis in atrial biopsies.

Conclusions

Detailed changes in sinus rhythm atrial electrophysiology can be imaged noninvasively and can be used to assess the impact and evolution of atrial fibrillation on atrial conduction properties in patients with mitral regurgitation. If replicated in larger studies, electrocardiographic imaging may identify patients with mitral regurgitation at risk for atrial fibrillation and could be used to guide treatment strategies.

Long-term results of the maze procedure with GP ablation for permanent atrial fibrillation

OBJECTIVES

We investigated the effect of the maze procedure with intensive pulmonary vein isolation (PVI) guided by ganglionated plexus (GP) mapping (the Maze with GP ablation group) on a long-term postoperative maintenance of sinus rhythm in patients with permanent atrial fibrillation (AF) and compared with that in patients undergoing the maze procedure with the conventional PVI (the Maze group).

METHODS AND RESULTS

We investigated 48 patients who underwent the maze procedure with GP ablation for persistent AF and 43 patients who underwent the maze procedure. The Maze procedure was conducted by the endocardial application of bipolar radiofrequency ablation and cryoablation. Conventional PVI was applied three times for the entrance of right and left PVs, respectively. Intensive PVI for GP ablation was repeated six-to-eight times for both sides of PVs to cover the bilateral GP regions identified by GP mapping. The duration of permanent AF, the prevalence of concomitant primary heart diseases, and the postoperative follow-up period were comparable between the two groups. At discharge, 1 year, 5 years after the surgery, sinus rhythm was maintained in 74.4%, 61%, and 40.5% of the Maze group. In contrast, it was maintained in 93.7%, 88.9%, and 75.7% of the Maze with GP ablation group. The cumulative freedom rate from AF at 10 years after surgery was significantly higher in the Maze with GP ablation group.

CONCLUSIONS

More intense PV isolation including adjacent GP may improve long-term results of maze procedure in patients with permanent AF.

European multicentre experience of staged hybrid atrial fibrillation ablation for the treatment of persistent and longstanding persistent atrial fibrillation

•

The 2 stage hybrid method combines epicardial and endocardial ablation.

•

Its main role is for drug refractory, long-standing persistent AF.

•

56% were free of atrial arrhythmia recurrence at 18 months post the second stage catheter ablation off antiarrhythmic drugs.

•

During follow-up 10.8% of patients had redo catheter ablation.

•

75% of the 175 patents were in sinus rhythm at latest clinical follow-up including those on antiarrhythmic drugs.

•

Clinically important complications occurred in 5% with 1 death (0.6%).

The management of non-paroxysmal atrial fibrillation (AF) remains controversial. We examined the efficacy and safety of the 2 stage Hybrid AF ablation approach by analysing the largest series of this technique reported so far.

Methods

The approach aims to electrically isolate the left atrial posterior wall incorporating the pulmonary veins (‘box-set’pattern). An initial video-assisted thoracoscopic (VATS) epicardial ablation is followed after a minimum of 8 weeks by endocardial radiofrequency catheter ablation.

Results

Of 175 patients from 4 European cardiothoracic centers, who underwent the surgical (COBRA Fusion, AtriCure Inc) 1st stage ablation, 166 went on to complete 2nd stage catheter ablation. At median follow up of 18 months post 2nd stage procedure 93/166 (56%) had remained free of AF or atrial tachycardia (AT) recurrence off antiarrhythmic drugs. 110/175 62.9% were in sinus rhythm off all antiarrhythmic drugs at last clinic follow-up (132/175 75.4% including those on antiarrhythmic drugs). 18 patients (10.8%) underwent a further re-do ablation (mean of 1.1 ablations per patient) 105/166 (63%) remained free of AF/AT recurrence off antiarrhythmic drugs following last ablation procedure.

Latterly, ILRs have been implanted in patients (n = 56); 60% have remained fully arrhythmia free and 80% have shown AF burden < 5% at a median 14 months follow-up [IQR: 13.5 (8–21.5)]. Only 10.9% have reverted to persistent AF. 5 patients (2.9%) had a perioperative stroke and 4 patients (2.3%) exhibited persistent weakness of the right hemidiaphragm following stage 1 VATS epicardial ablation. One patient died following stroke (overall mortality 0.6%).

Conclusions

In patients with non-paroxysmal AF with unfavourable characteristics for catheter ablation, the staged hybrid approach results in acceptable levels of freedom from recurrent atrial arrhythmia, however, complication rates are higher than with catheter ablation alone.

Five-year results of a modified left atrial maze IV procedure in the treatment of atrial fibrillation: a randomized study

Background

The left atrial maze IV (LAM‐IV) alone has been used to eliminate atrial fibrillation (AF) without severe right heart diseases. However, we felt that it could be improved and developed a modified LAM‐IV (MLAM‐IV). In this prospective trial, we aimed to investigate 5‐year clinical outcomes of AF in patients treated by the novel MLAM‐IV technique.

Methods

Between September 2012 and October 2013, 120 patients who underwent valve surgery and bipolar radiofrequency ablation for AF were randomized into the LAM‐IV group (n = 60) or MLAM‐IV group (n = 60). At postoperative follow‐up examinations, data were recorded at 1, 3 and 6 months, and annually thereafter.

Results

The mean ablation time and postoperative ventilation time were shorter in the MLAM‐IV group than in the LAM‐IV group (P < 0.001 and P = 0.03, respectively). At 5 years, the rate of freedom from AF was 69.0% in the MLAM‐IV group and 60.0% in the LAM‐IV group (hazard ratio 0.71, 95% confidence interval 0.39 to 1.32, P = 0.42). There were no differences with respect to the early operative mortality and major complications, late mortality, and major adverse events.

Conclusions

The MLAM‐IV provides a technically simpler ablation process. The MLAM‐IV was associated with less ventilation support in the early postoperative period. The long‐term efficacy of the MLAM‐IV in the treatment of AF is comparable to that of the LAM‐IV.

Novel concepts and approaches in ablation of atrial fibrillation: the role of non-pulmonary vein triggers

Ablation of non-pulmonary vein (PV) triggers is an important step to improve outcomes in atrial fibrillation ablation. Non-pulmonary vein triggers typically originates from predictable sites (such as the left atrial posterior wall, superior vena cava, coronary sinus, interatrial septum, and crest terminalis), and these areas can be ablated either empirically or after observing significant ectopy (with or without drug challenge). In this review, we will focus on ablation of non-PV triggers, summarizing the existing evidence and our current approach for their mapping and ablation.

A Minimally Invasive Stand-alone Cox-Maze Procedure Is as Effective as Median Sternotomy Approach

OBJECTIVE

The Cox-Maze IV procedure has been shown to be an effective treatment for atrial fibrillation when performed concomitantly with other operations either via median sternotomy or right minithoracotomy. Few studies have compared these approaches in patients with lone atrial fibrillation. This study examined outcomes with sternotomy versus minithoracotomy in stand-alone Cox-Maze IV procedures at our institution.

METHODS

Between 2002 and 2015, 195 patients underwent stand-alone biatrial Cox-Maze IV. Minithoracotomy was used in 75 patients, sternotomy in 120. Freedom from atrial tachyarrhythmias was ascertained using electrocardiography, Holter, or pacemaker interrogation at 3 to 60 months. Predictors of recurrence were determined using logistic regression.

RESULTS

Of 23 preoperative variables, the only differences between groups were that minithoracotomy patients had a higher rate of New York Heart Association 3/4 symptoms and a lower rate of previous stroke. Minithoracotomy and sternotomy patients had similar atrial fibrillation duration and type. Minithoracotomy patients had a smaller left atrial diameter (4.5 vs 4.8 cm, P = 0.03). More minithoracotomy patients received a box lesion (73/75 vs 100/120, P = 0.002). Minithoracotomy patients had a shorter hospital stay (7 vs 8 days, P = 0.009) and a similar rate of major complications (3/75 (4%) vs 7/120 (6%), P = 0.74). There were no differences in mortality or freedom from atrial tachyarrhythmias. Predictors of atrial fibrillation recurrence included a preoperative pacemaker, omission of the left atrial roof line, and New York Heart Association 3/4 symptoms.

CONCLUSIONS

Stand-alone Cox-Maze IV via minithoracotomy was as effective as via sternotomy with a shorter hospital stay. A minimally invasive approach is our procedure of choice.

Late outcome of surgical radiofrequency ablation for persistent valvular atrial fibrillation in China: a single-center study

Background

Atrial fibrillation (AF) adversely affects surgical outcomes of cardiac valve surgery. Surgical ablation is an effective way to treat valvular AF. The aim of this study was to evaluate the late outcome of surgical radiofrequency ablation and explore the risk factors of AF recurrence in Chinese patients undergoing cardiac valve surgery.

Methods

Three hundred ninety six consecutive patients with persistent valvular AF were enrolled in this study. They underwent concomitant modified Maze IV and were completed follow-ups. Cox survival regression model was used to screen independent risk factors for predicting late recurrence of AF.

Results

During the follow-up period of 28 (6 ~ 61) months, AF recurred in 151 patients (38.1%). In multivariate survival regression, factors predictive of AF late recurrence were AF duration, pre-operative serum B-type natriuretic peptide (BNP), pre-operative heart rate and left atrial diameter (LAD), post-operative atrial tachyarrhythmias and AF at discharge. According to receiver operating characteristic curve analysis, the best cutoff values for AF duration, BNP, heart rate and LAD were 66.5 months, 251 pg/ml, 82 beats/min and 67.9 mm, respectively.

Conclusions

Longer AF duration, larger LAD, higher BNP level and lower heart rate indicated a poor late outcome of surgical radiofrequency ablation in persistent AF patients undergoing cardiac valve surgery. Therefore, indication to radiofrequency ablation should be carefully considered in these patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13019-017-0627-z) contains supplementary material, which is available to authorized users.

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).

Surgical Ablation of Atrial Fibrillation: is Electrical Isolation of the Pulmonary Veins a Must?

Ablation of atrial fibrillation (AF) is a well-established treatment option for patients with symptomatic AF refractory to antiarrhythmic drugs. The cornerstone of catheter ablation is electrical isolation of the pulmonary veins, since the pulmonary veins are the most common location for triggers of AF. Electrical reconnection of the pulmonary veins is associated with arrhythmia recurrence and therefore diminishes long-term success of catheter ablation of AF. Therefore, durable pulmonary vein isolation remains a condition sine qua non for catheter ablation of AF. The Cox-Maze procedure is considered an effective surgical cure of AF, however it has never been widely adopted due to its procedural complexity. Since the development of minimal invasive techniques for surgical AF treatment, surgical ablation of AF has regained interest. Most of the minimal invasive surgical AF ablations performed around the globe include pulmonary vein isolation as a part of the procedure. In this review, we explore the necessity of electrical isolation of the pulmonary veins in surgical AF ablation.

A modified Cox maze IV procedure: a simpler technique for the surgical treatment of atrial fibrillation

OBJECTIVES

To determine the effectiveness of a simplified surgical treatment method for atrial fibrillation (AF).

METHODS

Between September 2012 and October 2013, 120 patients (mean age, 52.3 ± 8.8 years) underwent valve surgery and concomitant bipolar radiofrequency ablation for the treatment of AF. Patients were randomized to a Cox maze IV procedure (CMP-IV) group (n = 60) or a modified CMP-IV (MCMP-IV) group (n = 60). Freedom from AF was defined as freedom from any left atrial arrhythmia lasting <30 s and no requirement of antiarrhythmic drugs after 6 months. Data were recorded at postoperative follow-up examinations, which were scheduled at 1, 3, 6 and 12 months, and annually thereafter.

RESULTS

No ablation-related complications occurred in either group. The mean ablation time was longer in the CMP-IV group than in the MCMP-IV group (18.5 ± 1.7 vs 16.6 ± 1.6 min, P < 0.001). The mean follow-up time was 32.4 ± 3.6 months (range, 26-39 months). Freedom from AF tended to be higher, but not significantly so, among the MCMP-IV group than among the CMP-IV group over the entire follow-up period.

CONCLUSIONS

The MCMP-IV is an effective surgical procedure for the treatment of AF. In certain patients, such as those with anatomic variations of the pulmonary veins, the MCMP-IV is simpler than the CMP-IV.

CLINICAL TRIALS REGISTRATION ID

ChiCTR-TRC-12002742.

Catheter Ablation of Paroxysmal Atrial Fibrillation: Have We Achieved Cure with Pulmonary Vein Isolation?

Pulmonary vein isolation (PVI) is the cornerstone of current ablation techniques to eliminate atrial fibrillation (AF), with the greatest efficacy as a stand-alone procedure in patients with paroxysmal AF. Over the years, techniques for PVI have undergone a profound evolution, and current guidelines recommend PVI with confirmation of electrical isolation. Despite significant efforts, PV reconnection is still the rule in patients experiencing post-ablation arrhythmia recurrence. In recent years, use of general anesthesia with or without jet ventilation, open-irrigated ablation catheters, and steerable sheaths have been demonstrated to increase the safety and efficacy of PVI, reducing the rate of PV reconnection over follow-up. The widespread clinical availability of ablation catheters with real-time contact force information will likely further improve the effectiveness and safety of PVI. In a small but definite subset of patients, post-ablation recurrent arrhythmia is due to non-PV triggers, which should be eliminated in order to improve success. Typically, non-PV triggers cluster in specific regions such as the coronary sinus, the inferior mitral annulus, the interatrial septum, the left atrial appendage, the Eustachian ridge, the crista terminalis region, the superior vena cava, and the ligament of Marshall. Focal ablation targeting the origin of the trigger is recommended in most cases. Empirical non-PV ablation targeting the putative substrate responsible for AF maintenance with ablation lines and/or elimination of complex fractionated electrograms has not been shown to improve success compared to PVI alone. Similarly, the role of novel substrate-based ablation approaches targeting putative localized sources of AF (e.g., rotors) identified by computational mapping techniques is unclear, as they have never been compared to PVI and non-PV trigger ablation in an adequately designed randomized trial. This review highlights PVI techniques and outcomes in treating recurrent drug-refractory AF and discusses the potential role of additional non-PV ablation.

Treatment of stand-alone atrial fibrillation with a right thoracoscopic approach employing a microwave or monopolar radiofrequency energy source: long-term results

OBJECTIVES

Minimally invasive surgery for atrial fibrillation (AF) has rapidly evolved recently. The long-term efficacy of most of these procedures is poorly known.

METHODS

Between 2006 and 2010, 38 drug-resistant, symptomatic patients with stand-alone AF underwent unilateral, thoracoscopic, off-pump ablation. The mean age was 60 ± 8.2 (range 42-75) years and the mean AF duration was 46 ± 62 (range 3-240) months. Sixteen patients (42%) had paroxysmal, 9 (24%) had persistent and 13 (34%) had long-standing persistent AF. A box lesion was created using a microwave (26 patients) or monopolar radiofrequency (12 patients) system. Patients were prospectively followed with repeat electrocardiograms (ECGs) and ECG Holters. Additional catheter ablation was offered to patients with recurrence of arrhythmia.

RESULTS

All procedures were completed as planned with one conversion to sternotomy, zero mortality and minimal in-hospital complications. The mean follow-up duration was 70 ± 19 (range 20-88) months. Arrhythmia-free survival rates after the procedure were 50, 44.4, 24.1 and 10.8% at 6, 12, 36 and 60 months, respectively, with most recurrences in the first 6 months. Twelve patients underwent additional catheter ablation(s); from the last intervention, 75% of them were in sinus rhythm (SR) with a mean follow-up of 31 ± 23 (range 4-86) months. Overall, at the end of follow-up, only 3 patients were still in SR without any arrhythmia recurrence. Major complications (cerebral, peripheral embolism or bleeding) occurred in 5 patients.

CONCLUSIONS

Unilateral, thoracoscopic AF ablation is safe and technically feasible. However, the results of the microwave and monopolar radiofrequency devices were less than satisfactory, with a gradual decline in arrhythmia-free survival over a very long-term follow-up.

[Biatrial vs. isolated left atrial cryoablation for the treatment of long-lasting permanent atrial fibrillation. Midterm recurrence rate]

The long-term results of cryomaze in patients with longstanding persistent atrial fibrillation during concomitant surgical procedures are still uncertain.

METHODS

Between 2006 and 2011, 150 consecutive patients with associated long-lasting permanent atrial fibrillation and associated heart disease underwent heart surgery were treated by biatrial Cox-Maze (63 patients) or by isolated endocardial or epicardial left atrial cryoablation (83 patients) concomitantly. The results at 3 years in these groups were compared with clinical monitoring, electrocardiography, 24-hour Holter, and echocardiography with measurement of the transmitral A wave at 1, 6 and 12 months and annually thereafter in all patients.

RESULTS

Patients undergoing Cox-Maze IV ablation presented rates of freedom from atrial fibrillation of 97, 94, 89, 80 and 54% at 1, 6, 12, 24 and 36 months, respectively. In the 12-month follow-up, these differences were significant (p<.05). The independent risk factors of atrial fibrillation recurrence was isolated ablation of left atrium.

CONCLUSIONS

Atrial fibrillation by cryothermia ablation had a high success rate before 2 years postoperatively. Recurrence of atrial fibrillation increased thereafter regardless of the technique used, although it was more intense and developed earlier in cases of monoatrial ablation. For the treatment of other long-lasting permanent atrial fibrillation cardiac surgery-associated pathology, an aggressive biatrial treatment with Cox maze ablation should be performed.

Histopathology of Bipolar Radiofrequency Ablation in the Human Atrium

BACKGROUND

The Cox maze IV operation has become the preferred surgical treatment for atrial fibrillation, as it is associated with less morbidity and complexity than the Cox maze III procedure, yet is still highly effective. Numerous studies have been conducted in animals to examine the histopathology of this operation on the heart but studies on human hearts that have undergone the Cox maze IV operation have not been performed.

METHODS

We report the histopathologic findings in 3 patients from whom tissue was available for histologic study. In 2 patients it was obtained at autopsy within a month after undergoing a Cox maze IV operation, and in the remaining patient, atrial tissue was obtained immediately after ablation.

RESULTS

The lesions were clearly visible on the atria at day 6 and day 18. Microscopic examination showed that the hearts were in different stages of healing. We also found that, compared with animal models, human myocardium had significant preexisting underlying damage with myocyte hypertrophy and fibrosis. Although most of the ablative lesions were transmural, not all spanned from the epicardium to the endocardium. The chronic changes present in these hearts may have prevented transmurality by impeding energy delivery from fully penetrating the tissue.

CONCLUSIONS

The atrial myocardial substrate studied in experimental conditions is markedly different from the human hearts that frequently express histopathologic changes secondary to the underlying disease process. That may prevent creating true transmural lesions and impact final efficacy of the procedure.

Late outcomes after the Cox maze IV procedure for atrial fibrillation

OBJECTIVE

The Cox maze IV procedure (CMPIV) has been established as the gold standard for surgical ablation; however, late outcomes using current consensus definitions of treatment failure have not been well described. To compare to reported outcomes of catheter-based ablation, we report our institutional outcomes of patients who underwent a left-sided or biatrial CMPIV at 5 years of follow-up.

METHODS

Between January 2002 and September 2014, data were collected prospectively on 576 patients with AF who underwent a CMPIV (n = 532) or left-sided CMPIV (n = 44). Perioperative variables and long-term freedom from AF, with and without AADs, were compared in multiple subgroups.

RESULTS

Follow-up at any time point was 89%. At 5 years, overall freedom from AF was 93 of 119 (78%), and freedom from AF off AADs was 77 of 177 (66%). No differences were found in freedom from AF, with or without AADs, at 1, 2, 3, 4, and 5 years for patients with paroxysmal AF (n = 204) versus with persistent/longstanding persistent AF (n = 305), or for those who underwent standalone versus a concomitant CMP. Duration of preoperative AF and hospital length of stay were the best predictors of failure at 5 years.

CONCLUSIONS

The outcomes of the CMPIV remain good at late follow-up. The type of preoperative AF or the addition of a concomitant procedure did not affect late success. The results of the CMPIV remain superior to those reported for catheter ablation and other forms of surgical AF ablation, especially for patients with persistent or longstanding AF.

Adjunct ablation strategies for persistent atrial fibrillation-beyond pulmonary vein isolation

Atrial fibrillation (AF) is the most common sustained arrhythmia. Recent guidelines recommend pulmonary vein isolation (PVI) as the main procedural endpoint to control recurrent AF in symptomatic patients resistant to antiarrhythmic drugs. The efficacy of such procedure is higher in paroxysmal AF while is still unsatisfactory in persistent and long-standing persistent AF. This review will summarize the state-of-the-art of AF ablation techniques in patients with persistent AF, discussing the evidence underlying different approaches with a particular focus on adjunctive ablation strategies beyond PVI including linear ablation, ablation of complex fractionated atrial electrograms (CFAE), ablation of ganglionated plexi, dominant frequency, rotors and other anatomical sites frequently involved in AF triggers.

A Novel “Box Lesion” Minimally Invasive Totally Thoracoscopic Surgical Ablation for Atrial Fibrillation

Introduction: Minimally invasive surgical ablation is an emerging alternative method to catheter ablation and the full surgical maze procedure for nonpharmacologic treatment of atrial fibrillation (AF). We present a totally thoracoscopic “box lesion” radiofrequency ablation procedure in patients with paroxysmal or persistent AF. Materials and Methods: From June 2011 to October 2012, 14 patients with lone paroxysmal (n = 7) or persistent AF (n = 7) were enrolled in this study. Procedures were performed through 3 5-12 mm holes on each side of the chest wall. A bipolar ablation device was used to create a box lesion in the posterior wall of the left atrium that encircled the 4 pulmonary veins (achieving bilateral pulmonary vein/posterior left atrial wall isolation). Perioperative complications were recorded for all patients. Freedom from AF was assessed by 24-hour Holter monitoring every 3 months or during symptoms of arrhythmia. Results: The ablation was successfully performed in all patients, with median operation time of 128 minutes (range, 45 to 180 minutes). No operative mortality or morbidity were noted during the study period. Freedom from AF was achieved in 12 patients (85.7%) during follow-up (median follow-up 9 months). One patient with persistent AF was shifted to paroxysmal AF. No atrial flutter or atrial tachycardia was noted during the follow-up. Conclusion: These early results show that totally thoracoscopic surgical ablation using a unique “box lesion” procedure for persistent or paroxysmal AF is a feasible and effective method with good short-term results. Further study is necessary to validate this result. Key words: Arrhythmia therapy, Flutter, Surgery, Thoracoscopy

Complete Isolation of the Left Atrial Posterior Wall (Box Lesion) to Treat Longstanding Persistent Atrial Fibrillation

INTRODUCTION

The left atrial posterior wall has been shown to play na important role in AF pathophysiology.

OBJECTIVE

Evaluate the efficacy of an ablation strategy designed to completely isolate the LA posterior wall, on top of PV isolation. Methods and Results: 25 pts (72% male age 65 ± 12 years) undergoing AF ablation for persistent or long term persistent AF. Mean AF duration was 11 ± 3 months and mean LA diameter was 4.8 ± 0.4 mm. After complete PVI, a "Roof Line" was created between the top of each contralateral set of lesions and a "floor line" closed the posterior wall in a "Box" fashion, connecting the bottom of each set of contralateral lesions. After an average follow-up of 16 ± 2 months, 20 patients (80%) were free of any atrial arrhythmia recurrences (18 of whom off drugs). Five patients (20%) had sustained atypical flutter and required a new ablation procedure. All these patients had mitral isthmus dependent flutters and no electrical conduction in the PVs or posterior wall were detected.

CONCLUSIONS

Complete LA posterior wall isolation on top of PV is associated with good outcomes in patients with persistent and long-standing persistent AF when performed using meticulous bidirectional isolation criteria and adenosine infusion. Recurrences occur predominately as perimitral flutter, without gaps in the posterior wall.

A minimally invasive Cox maze IV procedure is as effective as sternotomy while decreasing major morbidity and hospital stay

OBJECTIVES

The Cox maze IV procedure has the best results for the surgical treatment of atrial fibrillation. It has been traditionally performed through sternotomy with excellent outcomes, but this has been considered to be too invasive. An alternative approach is to perform a less invasive right anterolateral minithoracotomy. This series compared these approaches at a single center in consecutive patients.

METHODS

Patients undergoing a Cox maze IV procedure (n = 356) were retrospectively reviewed from January 2002 to February 2014. Patients were stratified into 2 groups: right minithoracotomy (RMT; n = 104) and sternotomy (ST; n = 252). Preoperative and perioperative variables were compared as well as long-term outcomes. Patients were followed up for 2 years and rhythm was confirmed with an electrocardiogram or prolonged monitoring.

RESULTS

Freedom from atrial tachyarrhythmias off antiarrhythmic drugs was 81% and 74% at 1 and 2 years, respectively, using an RMT approach and was not significantly different from the ST group at these same time points. The overall complication rate was lower in the RMT group (6% vs 13%, P = .044) as was 30-day morality (0% vs 4%, P = .039). Median length of stay in the intensive care unit was lower in the RMT group than in the ST group (2 days [range, 0-21 days] vs 3 days [range, 1-61 days]; P = .004) as was median hospital length of stay (7 days [range, 4-35 days] vs 9 days [range, 1-111 days]; P < .001).

CONCLUSIONS

The Cox maze IV procedure performed through a right minithoracotomy is as effective as sternotomy in the treatment of atrial fibrillation. This approach was associated with fewer complications, decreased mortality and decreased length of stay in the intensive care unit and hospital length of stay.