Late outcomes after the Cox maze IV procedure for atrial fibrillation

Treating Atrial Fibrillation is No Maze: A Reminder to Heart Teams for Concomitant Surgical Ablation for Atrial Fibrillation With Cardiac Surgery

Atrial fibrillation (AF) is the most prevalent arrhythmia and is often found during times of other cardiac pathologies that require surgical management including coronary revascularization and valve surgery. Surgical ablation of AF, most frequently performed through the Cox-Maze IV procedure, is highly effective in restoring sinus rhythm. Despite robust society guideline recommendations for concomitant surgical ablation (CSA) for AF, the practice has yet to be widely adopted. In this review, we discuss the current indications for CSA, its efficacy in maintaining freedom from atrial tachyarrhythmias, stroke, and adverse long-term outcomes, the safety profile of SA when performed alongside cardiac surgical cases, and challenges with its implementation across the most common concomitant cardiac operations. In conclusion, we present a reminder to multidisciplinary heart teams to consider CSA when indicated for their patients.

Outcomes of Concomitant Maze Procedure in Tricuspid Repair for Severe Tricuspid Regurgitation

BACKGROUND

We aimed to analyze the impact of concomitant Maze procedure on the clinical and rhythm outcomes, and echocardiographic parameters in tricuspid repair for patients with severe tricuspid regurgitation (TR) and persistent atrial fibrillation (AF).

METHODS

Patients who had severe TR and persistent AF and underwent tricuspid valve (TV) repair were included in the study. Both primary TR and secondary TR were included in the current study. The study population was stratified according to Maze procedure. The primary outcome was major adverse cardiovascular and cerebrovascular event (MACCE) at 15 years post-surgery. Propensity-score matching analyses was performed to adjust baseline differences.

RESULTS

Three hundred seventy-one patients who underwent tricuspid repair for severe TR and persistent AF from 1994 to 2021 were included, and 198 patients (53.4%) underwent concomitant Maze procedure. The maze group showed 10-year sinus rhythm (SR) restoration rate of 55%. In the matched cohort, the maze group showed a lower cumulative incidence of cardiac death (4.6% vs. 14.4%, P = 0.131), readmission for heart failure (8.1% vs. 22.2%, P = 0.073), and MACCE (21.1% vs. 42.1%, P = 0.029) at 15 years compared to the non-maze group. Left atrial (LA) diameter significantly decreased in the maze group at 5 years (53.3 vs. 59.6 mm, P < 0.001) after surgery compared to preoperative level, and there was a significant difference in the change of LA diameter over time between the two groups (P = 0.013).

CONCLUSION

The Maze procedure during TV repair in patients with severe TR and persistent AF showed acceptable SR rates and lower MACCE rates compared to those without the procedure, while also promoting LA reverse remodeling.

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

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

Safety and efficacy of Cox-Maze procedure for atrial fibrillation during mitral valve surgery: a meta-analysis of randomized controlled trials

BACKGROUND

Cox-Maze procedure is currently the gold standard treatment for atrial fibrillation (AF). However, data on the effectiveness of the Cox-Maze procedure after concomitant mitral valve surgery (MVS) are not well established. The aim of this study was to assess the safety and efficacy of Cox-Maze procedure versus no-maze procedure n in AF patients undergoing mitral valve surgery through a systematic review of the literature and meta-analysis.

METHODS

A systematic search on PubMed/MEDLINE, EMBASE, and Cochrane Central Register of Clinical Trials (Cochrane Library, Issue 02, 2017) databases were performed using three databases from their inception to March 2023, identifying all relevant randomized controlled trials (RCTs) comparing Cox-Maze procedure versus no procedure in AF patients undergoing mitral valve surgery. Data were extracted and analyzed according to predefined clinical endpoints.

RESULTS

Nine RCTs meeting the inclusion criteria were included in this systematic review with 663 patients in total (341 concomitant Cox-Maze with MVS and 322 MVS alone). Across all studies with included AF patients undergoing MV surgery, the concomitant Cox-Maze procedure was associated with significantly higher sinus rhythm rate at discharge, 6 months, and 12 months follow-up when compared with the no-Maze group. Results indicated that there was no significant difference between the Cox-Maze and no-Maze groups in terms of 1 year all-cause mortality, pacemaker implantation, stroke, and thromboembolism.

CONCLUSIONS

Our systematic review suggested that RCTs have demonstrated the addition of the Cox-Maze procedure for AF leads to a significantly higher rate of sinus rhythm in mitral valve surgical patients, with no increase in the rates of mortality, pacemaker implantation, stroke, and thromboembolism.

Novel Entropy-Based Metrics for Long-Term Atrial Fibrillation Recurrence Prediction Following Surgical Ablation: Insights from Preoperative Electrocardiographic Analysis

Atrial fibrillation (AF) is a prevalent cardiac arrhythmia often treated concomitantly with other cardiac interventions through the Cox-Maze procedure. This highly invasive intervention is still linked to a long-term recurrence rate of approximately 35% in permanent AF patients. The aim of this study is to preoperatively predict long-term AF recurrence post-surgery through the analysis of atrial activity (AA) organization from non-invasive electrocardiographic (ECG) recordings. A dataset comprising ECGs from 53 patients with permanent AF who had undergone Cox-Maze concomitant surgery was analyzed. The AA was extracted from the lead V1 of these recordings and then characterized using novel predictors, such as the mean and standard deviation of the relative wavelet energy (RWEm and RWEs) across different scales, and an entropy-based metric that computes the stationary wavelet entropy variability (SWEnV). The individual predictors exhibited limited predictive capabilities to anticipate the outcome of the procedure, with the SWEnV yielding a classification accuracy (Acc) of 68.07%. However, the assessment of the RWEs for the seventh scale (RWEs7), which encompassed frequencies associated with the AA, stood out as the most promising individual predictor, with sensitivity (Se) and specificity (Sp) values of 80.83% and 67.09%, respectively, and an Acc of almost 75%. Diverse multivariate decision tree-based models were constructed for prediction, giving priority to simplicity in the interpretation of the forecasting methodology. In fact, the combination of the SWEnV and RWEs7 consistently outperformed the individual predictors and excelled in predicting post-surgery outcomes one year after the Cox-Maze procedure, with Se, Sp, and Acc values of approximately 80%, thus surpassing the results of previous studies based on anatomical predictors associated with atrial function or clinical data. These findings emphasize the crucial role of preoperative patient-specific ECG signal analysis in tailoring post-surgical care, enhancing clinical decision making, and improving long-term clinical outcomes.

Delayed-enhancement cardiac magnetic resonance imaging detects disease progression in patients with mitral valve disease and atrial fibrillation

Objectives

The mechanism by which mitral valve (MV) disease leads to atrial fibrillation (AF) remains poorly understood. Delayed-enhancement cardiac magnetic resonance imaging (DE-MRI) has been used to assess left atrial (LA) fibrosis in patients with lone AF before catheter ablation; however, few studies have used DE-MRI to assess MV-induced LA fibrosis in patients with or without AF undergoing MV surgery.

Methods

Between March 2018 and September 2022, 38 subjects were enrolled; 15 age-matched controls, 14 patients with lone mitral regurgitation (MR), and 9 patients with MR and AF (MR + AF). Indexed LA volume, total LA wall, and regional LA posterior wall (LAPW) enhancement were defined by the DE-MRI. One-way analysis of variance was performed.

Results

LA volume and LA enhancement were associated (r = 0.451, P = .004). LA volume differed significantly between controls (37.1 ± 10.6 mL) and patients with lone MR (71.0 ± 35.9, P = .020 and controls and patients with MR + AF (99.3 ± 47.4, P < .001). The difference in LA enhancement was significant between MR + AF (16.7 ± 9.6%) versus controls (8.3 ± 3.9%, P = .006) and MR + AF versus lone MR (8.0 ± 4.8%, P = .004). Similarly, the was significantly more LAPW enhancement in the MR + AF (17.5 ± 8.7%) versus control (9.2 ± 5.1%, P = .011) and MR + AF versus lone MR (9.8 ± 6.0%, P = .020).

Conclusions

Patients with MR + AF had significantly more total and LAPW fibrosis compared with both controls and lone MR. Volume and delayed enhancement were associated, but there was no difference between MR and MR + AF.

Minimally Invasive Mitral Valve Surgery With Concomitant Cox Maze Procedure Is as Effective as a Median Sternotomy With Decreased Morbidity

OBJECTIVE

A right minithoracotomy (RMT) is a minimally invasive surgical approach that has been increasingly performed for the concomitant Cox maze IV procedure (CMP) and mitral valve surgery (MVS). Little is known regarding whether long-term rhythm and survival outcomes are affected by the RMT as compared with the traditional median sternotomy (MS) approach.

METHODS

Between April 2004 and April 2021, 377 patients underwent the concomitant CMP and MVS, of whom 38% had RMT. Propensity score matching yielded 116 pairs. Freedom from atrial tachyarrhythmias (ATA) was assessed with prolonged monitoring annually for 8 years. Survival, rhythm, and perioperative outcomes were compared.

RESULTS

The unmatched RMT cohort had a greater freedom from ATA recurrence at 1 year (99% vs 90%, P = 0.001) and 3 years (94% vs 86%, P = 0.045). The matched RMT cohort had longer cardiopulmonary bypass (median: 215 [199 to 253] vs 170 [136 to 198] min, P < 0.001) and aortic cross-clamp (110 [98 to 124] vs 86 [71 to 102] min, P < 0.001) times but shorter intensive care time (48 [24 to 95] vs 71 [26 to 144] h, P = 0.001) and length of stay (8 [6 to 11] vs 10 [7 to 14] h, P < 0.001). More pacemakers (18% vs 4%, P < 0.001) and postoperative transfusions (57% vs 41%, P = 0.014) occurred in the MS cohort. The 30-day mortality (P = 0.651) and 8-year survival (P = 0.072) was not significantly different between the cohorts.

CONCLUSIONS

Early 1-year and 3-year freedom from ATA recurrence was better in the RMT cohort compared with the MS cohort. Despite longer operative times, the RMT cohort had shorter lengths of stay, fewer postoperative transfusions, and fewer pacemakers placed.

Concomitant ablation of atrial fibrillation: New pacemakers and early rhythm recovery

OBJECTIVE

New permanent pacemaker (PPM) implantation after concomitant atrial fibrillation (AF) ablation has been associated with surgical ablation (SA). We sought to determine factors for PPM use as well as early rhythm recovery.

METHODS

From 2004 through 2019, 6135 patients underwent valve surgery and were grouped: No AF (n = 4584), AF no SA (n = 346), and AF with SA (n = 1205) to evaluate predischarge PPM and 3-month rhythm recovery (intrinsic heart rate >40 beats per minute).

RESULTS

Overall, 282 (4.6%) patients required a predischarge PPM: atrioventricular node dysfunction in 75.3%, sick sinus syndrome in 19.1%, both (5%), and indeterminate (0.7%). Patients with AF had more PPMs: AF with SA (7.9%) versus AF no SA (6.9%) versus No AF (3.6%) (P < .001). For patients with AF, PPM rates were not significantly higher for ablation patients (7.6% SA vs 6.9% AF no SA; P = .56). There were differences in PPM by SA lesion set (biatrial 12.8%; left atrial only 6.1%; pulmonary vein isolation 3.0%; P < .001). Among patients with AF treated with 3-month PPM follow-up, rhythm recovery was common (35 out of 62 [56.5%]) and did not differ by lesion set. Rhythm recovery was seen in 63 out of 141 (44.7%) in the atrioventricular node dysfunction group versus 24 out of 35 (68.6%) in the sick sinus syndrome group (P = .011). In propensity score-matched groups, late survival was similar (P = .63) for new PPM patients.

CONCLUSIONS

Avoiding conduction system trauma and delaying implantation reduces the need for postoperative PPM. Rhythm recovery within 3 months is frequent, especially for patients with sick sinus syndrome. A conservative approach to the implantation of a new PPMs is warranted.

Three Ablation Techniques for Atrial Fibrillation during Concomitant Cardiac Surgery: A Systematic Review and Network Meta-Analysis

Atrial fibrillation (AF) ablation is a frequent procedure used in concomitant cardiac surgery. However, uncertainty still exists concerning the optimal extent of lesion sets. Hence, the objective of this study was to assess the results of various ablation techniques, aiming to offer a reference for clinical decision making. This review is listed in the prospective register of systematic reviews (PROSPERO) under ID CRD42023412785. A comprehensive search was conducted across eight databases (Scopus, Google Scholar, EBSCOHost, PubMed, Medline, Wiley, ProQuest, and Embase) up to 18 April 2023. Studies were critically appraised using the Cochrane Risk of Bias 2.0 for randomized control trials (RCTs) and the Newcastle Ottawa Scale adapted by the Agency for Healthcare Research and Quality (AHRQ) for cohort studies. Forest plots of pooled effect estimates and surface under the cumulative ranking (SUCRA) were used for the analysis. Our analysis included 39 studies and a total of 7207 patients. Both bi-atrial ablation (BAA) and left atrial ablation (LAA) showed similar efficacy in restoring sinus rhythm (SR; BAA (77.9%) > LAA (76.2%) > pulmonary vein isolation (PVI; 66.5%); LAA: OR = 1.08 (CI 0.94-1.23); PVI: OR = 1.36 (CI 1.08-1.70)). However, BAA had higher pacemaker implantation (LAA: OR = 0.51 (CI 0.37-0.71); PVI: OR = 0.52 (CI 0.31-0.86)) and reoperation rates (LAA: OR = 0.71 (CI 0.28-1.45); PVI: OR = 0.31 (CI 0.1-0.64)). PVI had the lowest efficacy in restoring SR and a similar complication rate to LAA, but had the shortest procedure time (Cross-clamp (Xc): PVI (93.38) > LAA (37.36) > BAA (13.89)); Cardiopulmonary bypass (CPB): PVI (93.93) > LAA (56.04) > BAA (0.03)). We suggest that LAA is the best surgical technique for AF ablation due to its comparable effectiveness in restoring SR, its lower rate of pacemaker requirement, and its lower reoperation rate compared to BAA. Furthermore, LAA ranks as the second-fastest procedure after PVI, with a similar CPB time.

Targeted Atrial Fibrillation Therapy and Risk Stratification Using Atrial Alternans

Atrial fibrillation (AF) is the most persistent arrhythmia today, with its prevalence increasing exponentially with the rising age of the population. Particularly at elevated heart rates, a functional abnormality known as cardiac alternans can occur prior to the onset of lethal arrhythmias. Cardiac alternans are a beat-to-beat oscillation of electrical activity and the force of cardiac muscle contraction. Extensive evidence has demonstrated that microvolt T-wave alternans can predict ventricular fibrillation vulnerability and the risk of sudden cardiac death. The majority of our knowledge of the mechanisms of alternans stems from studies of ventricular electrophysiology, although recent studies offer promising evidence of the potential of atrial alternans in predicting the risk of AF. Exciting preclinical and clinical studies have demonstrated a link between atrial alternans and the onset of atrial tachyarrhythmias. Here, we provide a comprehensive review of the clinical utility of atrial alternans in identifying the risk and guiding treatment of AF.

Concomitant surgical ablation for atrial fibrillation is associated with increased risk of acute kidney injury but improved late survival

BACKGROUND

Acute kidney injury (AKI) after cardiac surgery remains a common complication that has been associated with increased morbidity and mortality. This study implemented Kidney Disease Improving Global Outcomes criteria to evaluate renal outcomes after concomitant surgical ablation for atrial fibrillation.

METHODS

Patients with a history of atrial fibrillation who underwent elective cardiac surgery at our institution from 2008 to 2018 were retrospectively reviewed. Those with preoperative renal dysfunction were excluded. Patients were classified as those who underwent concomitant Cox-Maze IV (CMP-IV) (n = 376) or no surgical ablation (n = 498). Nearest neighbor 1:1 propensity matching was conducted on fourteen covariates. AKI was evaluated by mixed effects logistic regression analysis. Long-term survival was evaluated by proportional hazards regression.

RESULTS

Propensity matching yielded 308 patients in each group (n = 616). All preoperative variables were similar between groups. The concomitant CMP-IV group had a greater incidence of AKI: 32% (n = 99) versus 16% (n = 49), P &lt; .001. After accounting for bypass time and nonablation operations on mixed effects analysis, concomitant CMP-IV was associated with increased risk of AKI (odds ratio, 1.89; confidence interval, 1.12-3.18; P = .017). While AKI was associated with decreased late survival (P &lt; .001), patients who received a concomitant CMP-IV maintained superior 7-year survival to patients who received no ablation (P &lt; .001). No patients required permanent dialysis.

CONCLUSIONS

Concomitant CMP-IV was independently associated with increased risk of AKI in the acute postoperative period. However, the long-term risks of AKI were offset by the significant survival benefit of CMP-IV. Concerns regarding new-onset renal dysfunction should not prohibit recommendation of this procedure in appropriate patients.

Bi-atrial versus left atrial ablation for patients with rheumatic mitral valve disease and non-paroxysmal atrial fibrillation (ABLATION): rationale, design and study protocol for a multicentre randomised controlled trial

INTRODUCTION

Atrial fibrillation (AF) is common in patients with rheumatic mitral valve disease (RMVD) and increase the risk of stroke and death. Bi-atrial or left atrial ablation remains controversial for treatment of AF during mitral valve surgery. The study aims to compare the efficacy and safety of bi-atrial ablation with those of left atrial ablation among patients with RMVD and persistent or long-standing persistent AF.

METHODS AND ANALYSIS

The ABLATION trial (Bi-atrial vs Left Atrial Ablation for Patients with RMVD and Non-paroxysmal AF) is a prospective, multicentre, randomised controlled study. The trial will randomly assign 320 patients with RMVD and persistent or long-standing persistent AF to bi-atrial ablation procedure or left atrial ablation procedure in a 1:1 randomisation. The primary end point is freedom from documented AF, atrial flutter or atrial tachycardia of >30 s at 12 months after surgery off antiarrhythmic drugs. Key secondary end point is the probability of freedom from permanent pacemaker implantation at 12 months after surgery. Secondary outcomes include the probability of freedom from any recurrence of atrial tachyarrhythmias with antiarrhythmic drugs, AF burden, incidence of adverse events and cardiac function documented by echocardiography at 12 months after operation.

ETHICS AND DISSEMINATION

The central ethics committee at Fuwai Hospital approved the ABLATION trial. The results of this study will be disseminated through publications in peer-reviewed journals and conference presentations.

TRIAL REGISTRATION NUMBER

NCT05021601.

Comparing mid-term outcomes of Cox-Maze procedure and pulmonary vein isolation for atrial fibrillation after concomitant mitral valve surgery: A systematic review

BACKGROUND

Although concomitant pulmonary vein isolation (PVI) is used more frequently than the Cox-Maze procedure, which is currently the gold standard treatment for atrial fibrillation (AF), data on the comparative effectiveness of the two procedures after concomitant mitral valve (MV) surgery are still limited.

OBJECTIVE

We conducted a systematic review to identify randomized controlled trials (RCTs) and observational studies comparing the mid-term mortality and recurrence of AF after concomitant Cox-Maze and PVI in patients with AF undergoing MV surgery based on 12-month follow-up.

METHODS

Medline, EMBASE databases, and the Cochrane Library were searched from 1987 up to March 2022 for studies comparing concomitant Cox-Maze and PVI. Additionally, a meta-analysis of RCTs was performed to compare the mid-term clinical outcomes between these two surgical ablation techniques.

RESULTS

Three RCTs and three observational studies meeting the inclusion criteria were included in this systematic review with 790 patients in total (532 concomitant Cox-Maze and 258 PVI during MV surgery). Most studies reported that the concomitant Cox-Maze procedure was associated with higher freedom from AF at 12-month follow-up than PVI. Regarding AF recurrence, estimates pooled across the three RCTs indicated large heterogeneity and high uncertainty. In the largest and highest quality RCT, 12-month AF recurrence was higher in the PVI arm (risk ratio = 1.58, 95% CI: 0.91-2.73). In two out of three higher-quality observational studies, 12-month AF recurrence was higher in PVI than in the Cox-Maze arm (estimated adjusted probabilities 11% vs. 8% and 35% vs. 17%, respectively). RCTs demonstrated comparable 12-month mortality between concomitant Cox-Maze and PVI, while observational studies demonstrated the survival benefit of Cox-Maze.

CONCLUSIONS

Concomitant Cox-Maze in AF patients undergoing MV surgery is associated with better mid-term freedom from AF when compared to PVI with comparable mid-term survival. Large observational studies suggest that there might be a mid-term survival benefit among patients after concomitant Cox-Maze. Further large RCTs with longer standardized follow-up are required to clarify the benefits of concomitant Cox-Maze in AF patients during MV surgery.

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.

An off-pump biatrial mini-maze procedure for long-standing persistent atrial fibrillation

OBJECTIVE

The present study aimed to determine the safety and efficacy of a modified off-pump biatrial mini-maze procedure to treat long-standing persistent atrial fibrillation.

METHODS

Patients of long-standing persistent atrial fibrillation underwent our modified mini-maze procedure using bipolar radiofrequency ablation. Those patients firstly underwent a mini-maze procedure using Dallas lesion set protocol. Secondly, a purse-string suture was performed on the right atrium, and then four ablation lesions were made to the superior vena cava, the inferior vena cava, the appendix of the right atrium, and the tricuspid valve annulus from the purse-string suture point by the bipolar radiofrequency clamp. After the operation, the patients were followed up at 3, 6, 12 months, and every 1 year after that.

RESULTS

A total of 102 patients were included in the study. There was no mortality, no surgical re-exploration for bleeding, and no permanent pacemaker implantation. The intraoperative cardioversion rate was 42.2% (43/102). A follow-up at interval of 3, 6, 12, 24, 36, and 48 months showed a success rate free from long-standing persistent atrial fibrillation was 95.1% (97/102), 94.4% (85/90), 94.8% (73/77), 91.5% (54/59), 90.3% (28/31) and 86.4% (19/22), while freedom from atrial fibrillation off antiarrhythmic drugs was 88.2% (90/102), 85.6% (77/90), 81.8% (63/77), 78.0% (46/59), 74.2% (23/31), and 68.2% (15/22) respectively.

CONCLUSIONS

The modified biatrial mini-maze showed a safe and feasible procedure. Early follow-up demonstrated an acceptable success rate free from atrial fibrillation.

Radiofrequency Ablation in Patients Undergoing Mitral Valve Surgery with or without Giant Left Atria

Purpose: We aimed to compare the efficacy of radiofrequency ablation (RFA) in patients undergoing mitral valve (MV) surgery with or without giant left atria.

Methods: This retrospective, single-center, cohort study investigated patients who underwent MV surgery and concomitant RFA from 2009 to 2019. Patients were divided into non-giant left atria (diameter ≤65 mm, n = 1543) and giant left atria (diameter >65 mm, n = 241) groups. Five-year freedom from atrial tachyarrhythmia recurrence and thromboembolic event (TE) rates were assessed with death as the competing risk factor with and without propensity-score matching.

Results: Patients with giant left atria had higher mortality (10.8% versus 6.2%, P = 0.008) and readmission rates for heart failure than those without (12.0% versus 6.8%, P = 0.004). Atrial tachyarrhythmia recurrence rates were higher in patients with giant left atria than in those without (49% versus 24% at 5 years, P <0.001), but the cumulative incidence of TEs before (P = 0.944) and after (P = 0.695) propensity-score matching was comparable.

Conclusions: RFA effectively prevented TEs in patients with giant left atria, despite significant atrial tachyarrhythmia recurrence. Atrial tachyarrhythmia recurrence did not increase the risk of TEs. A lower success rate should be considered when deciding whether to perform surgical ablation in patients with giant left atria.

Staged hybrid totally thoracoscopic maze and catheter ablation for atrial fibrillation

INTRODUCTION

Atrial fibrillation (AF) is a growing health problem and is associated with increased risk of stroke. The Cox-Maze surgical procedure has offered the highest success rate, but utilization of this technique is low due to procedure invasiveness and complexity. Advances in catheter ablation and minimally invasive surgical techniques offer new options for AF treatment.

METHODS

In this review, we describe current trends and outcomes of minimally invasive treatment of persistent and long-standing persistent AF.

RESULTS

Treatment of persistent and long-standing persistent AF can be successfully treated using a team approach combining cardiac surgery and electrophysiology procedures. With this approach, the 1-year freedom from AF off antiarrhythmic drugs was 85%.

DISCUSSION

There are a variety of techniques and approaches used around the world as technology evolves to help develop new treatment strategies for AF. Our report will focus on a hybrid treatment approach using surgical and electrophysiology approaches providing enhanced treatment options by replicating Cox-Maze IV lesions using skills from each specialty. Closure of the left atrial appendage as part of these procedures enhances protection from late stroke. A team approach provides a cohesive evaluation, treatment, and monitoring plan for patients. Development of successful, less invasive treatment options will help address the growing population of patients with AF.

The Hybrid Convergent Procedure for Persistent and Long-Standing Persistent Atrial Fibrillation From an Electrophysiologist's Perspective

In atrial fibrillation (AF), the pulmonary veins (PV) are central to arrhythmogenicity and are targeted by PV isolation (PVI). As AF progresses, triggers become more prevalent in non-PV areas including the left atrial posterior wall (LAPW). Reported benefits of LAPW isolation in Cox-maze IV led to exploration of ablation strategies using endocardial catheters. However, no single approach to endocardial LAPW isolation exists. Relative success in comparison to PVI alone has been mixed. The hybrid convergent procedure was developed to combine minimally invasive surgical and electrophysiology techniques to accomplish effective PVI and LAPW isolation. Epicardial LAPW isolation is performed by a cardiothoracic surgeon followed by endocardial ablation by an electrophysiologist who ensures PVI completion and targets any remaining gaps. Safety and effectiveness of hybrid convergent was evaluated in the prospective, multi-center, randomized controlled trial, Convergence of Epicardial and Endocardial Ablation for the Treatment of Symptomatic Persistent AF (CONVERGE). CONVERGE compared the effectiveness of the hybrid convergent procedure to endocardial catheter ablation for treatment of drug-refractory persistent and longstanding persistent AF and demonstrated primary effectiveness of higher freedom from atrial arrhythmias absent new/increased dose previously failed/intolerant anti-arrhythmic drugs through 12 months compared to endocardial catheter ablation. Greater freedom from AF and proportion of patients experiencing ≥90% burden reduction with hybrid convergent ablation were seen through 18 months follow-up. Improved electrophysiology lab efficiency was demonstrated by the reduction in endocardial ablation time with addition of epicardial ablation. This multi-disciplinary heart team procedure may improve outcomes in difficult-to-treat patients with advanced AF. This article is protected by copyright. All rights reserved.

Ten year experience with the concomitant Maze IV procedure for atrial fibrillation

OBJECTIVE

The Maze IV (M-IV) procedure is regarded as the golden standard in treatment for surgical ablation of atrial fibrillation (AF); however, long-term follow-up results are scarce. We present our institutional 10-year experience.

METHODS

We collected data of 117 consecutive patients who have undergone a concomitant M-IV procedure between April 2006 and April 2016. Primary endpoints are freedom of atrial arrhythmias and freedom of atrial arrhythmias off antiarrhythmic drugs (AAD).

RESULTS

Forty-seven patients (40.2%) had paroxysmal AF. Two-thirds of the procedures included mitral valve surgery. The average follow-up time per patient was 3.8 years (SD 2.8). Freedom of AF at 1 year was 79%, at 5 years freedom of AF was 69% and freedom of AF off AAD was 56%. Predictors of AF recurrence in multivariate analysis were age, preoperative pacemakers, redo cardiac surgery and in-hospital AF. Preoperative PVI ablation was found to be a protective factor.

CONCLUSIONS

The long-term outcomes of the M-IV procedure are good and remain stable over the years. Results could be improved if follow-up were to be intensified and recurrences dealt with aggressively. Key question: How many patients are free from AF in a 10-year period after concomitant M-IV surgical ablation? Key findings: In the long term around 70% of patients are free of AF with an increasing need for anti-arrhythmic drugs. Take home message: Early to midterm freedom from AF after concomitant M-IV procedure is high and remains stable after 3 years.

Hybrid Ablation for Atrial Fibrillation: Safety & Efficacy of Unilateral Epicardial Access

Hybrid ablation combines thoracoscopic epicardial ablation with percutaneous catheter based endocardial ablation for the treatment of AF. The purpose of this study was to evaluate the safety and efficacy of hybrid ablation surgery for the treatment of atrial fibrillation (AF), and to compare outcomes of unilateral versus bilateral thoracoscopic epicardial ablation. Patients with documented AF who underwent hybrid ablation were followed post-operatively for major events. Major events were classified into two categories consisting of 1) safety, comprising all-cause mortality and major morbidities, and 2) efficacy, which included recurrence of atrial arrhythmia, cessation of antiarrhythmic drugs (AAD), and completeness of lesion set. A total of 84 consecutive patients were consented for hybrid ablation. Patients presented with an average AF duration of 85.9 months before hybrid ablation. 80 patients underwent successful thoracoscopic epicardial ablation. At one-year, 87% (60/69) of patients were free from AF and 73% (50/69) were free from AF and off AAD. 63 patients completed both epicardial and endocardial hybrid ablation with posterior wall isolation achieved in 89% (56/63) of patients. Unilateral epicardial ablation was associated with significantly shorter hospital length of stay compared to bilateral surgical approached (3.9 vs. 6.7 days, p = 0.002) with no difference in freedom from AF between groups at 1 year. Hybrid ablation for atrial fibrillation is effective for patients at high risk for recurrence after catheter ablation. The unilateral surgical approach may be associated with shorter hospital stay with no appreciable effect on procedure success rates. This study evaluates the safety and efficacy of unilateral epicardial access for hybrid ablation in patients with symptomatic atrial fibrillation refractory to antiarrhythmic treatment. Hybrid ablation for atrial fibrillation is effective for patients at high risk for recurrence after catheter ablation. The unilateral surgical approach may be associated with shorter hospital stay with no appreciable effect on procedure success rates.

Does left atrial epicardial conduction time reflect atrial fibrosis and the risk of atrial fibrillation recurrence after thoracoscopic ablation? Post hoc analysis of the AFACT trial

OBJECTIVES

To determine the association between left atrial epicardial conduction time (LAECT), fibrosis and atrial fibrillation (AF) recurrence after thoracoscopic surgical ablation of persistent AF.

SETTING

Single tertiary care centre in the Netherlands.

PARTICIPANTS

Patients with persistent AF from the randomised Atrial Fibrillation Ablation and Autonomic Modulation via Thoracoscopic Surgery (AFACT)-trial were included. Patients eligible for thoracoscopic AF ablation were included, full inclusion and exclusion criteria were previously published. All patients underwent thoracoscopic ablation, encompassing pulmonary vein isolation with an additional roof and trigone lesion. In patients with conduction block across the roof and trigone lesion, LAECT was measured. LAECT was defined as the time to local activation at one side of the roofline on pacing from the opposite side. Collagen fibre density was quantified from left atrial appendage histology.

OUTCOME MEASURES

Primary outcome: AF recurrence during 2 years of follow-up.

RESULTS

121 patients were included, of whom 35(29%) were women, age was 60.4±7.8 and 51% (62) had at least one AF recurrence during 2 years of follow-up. LAECT was longer in patients with versus without AF recurrence (182±43 ms vs 147±29 ms, p<0.001). LAECT was longer in older patients, in patients with a higher body mass index (BMI) and in patients using class IC antiarrhythmic drugs. LAECT was shorter in patients with higher collagen fibre density. A previously failed catheter ablation, LAECT and BMI were independently associated with AF recurrence.

CONCLUSION

LAECT is correlated with collagen fibre density and BMI and is independently associated with AF recurrence in patients with persistent AF. In these patients, LAECT appears to reflect substrate characteristics beyond clinical AF type and left atrial volume.

TRIAL REGISTRATION NUMBER

NCT01091389.

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.

Atrial fibrillation in patients with coronary heart disease: current state of the problem

Atrial fibrillation is one of the most common types of cardiac arrhythmia observed in clinical practice. Despite advances in the diagnosis and treatment, atrial fibrillation remains one of the leading causes of cardiovascular mortality and morbidity. In addition, atrial fibrillation is quite often combined with other pathologies of the cardiovascular system and is a marker of an unfavorable outcome. Several previous studies have demonstrated reduced survival in patients with coronary artery disease and atrial fibrillation who have not undergone surgery for arrhythmia. According to other data, the presence of preoperative atrial fibrillation among patients undergoing isolated coronary artery bypass grafting was associated with significantly higher rates of major postoperative complications. Nowadays, no one doubts the fact that atrial fibrillation during a coronary artery bypass surgery is a risk factor for increased hospital mortality, postoperative morbidity and leads to a decrease in the long-term survival. The studies confirm the necessity of surgical ablation for atrial fibrillation during coronary revascularization to reduce both short-term and long-term postoperative mortality and late complications.

Impact of maze procedure in patients with severe tricuspid regurgitation and persistent atrial fibrillation

OBJECTIVE

Patients with severe tricuspid regurgitation and persistent atrial fibrillation may not be good candidates for maze procedure due to preoperative atrial remodeling and various comorbidities. We attempted to evaluate the rhythm and clinical outcomes of maze procedure in these patients.

METHODS

Patients with severe tricuspid regurgitation and persistent atrial fibrillation who underwent tricuspid valve surgery between January 1994 and December 2017 at a single tertiary center were analyzed. The primary end point was sinus rhythm restoration. The key secondary end point was major adverse cardiovascular and cerebrovascular event rate, which is the composite event of stroke, cardiac death, major bleeding, and readmission for heart failure. Propensity score matching analysis was used.

RESULTS

A total of 388 patients underwent tricuspid valve surgery, and among them 172 patients (44%) underwent concomitant maze procedure. The maze group had sinus rhythm restoration rate of 56% in 9 years. Further, in the matched cohort, the maze group had higher freedom from major adverse cardiovascular and cerebrovascular event rate at 10 years than the nonmaze group (55.6% vs 36.2%; P = .047). Preoperative left atrial diameter (hazard ratio, 1.022; 95% CI, 1.012-1.033; P < .001) and right atrial diameter (hazard ratio, 1.012; 95% CI, 1.003-1.022; P = .013) were independent risk factors for failure of sinus rhythm.

CONCLUSIONS

Maze procedure in severe tricuspid regurgitation and persistent atrial fibrillation had acceptable rates of sinus rhythm restoration and reduced major adverse cardiovascular and cerebrovascular events in the long-term. Careful patient selection considering preoperative atrial diameters is needed to enhance maze success rate and long-term clinical outcomes.

Size matters in atrial fibrillation: the underestimated importance of reduction of contiguous electrical mass underlying the effectiveness of catheter ablation

Evidence has accumulated over the last century of the importance of a critical electrical mass in sustaining atrial fibrillation (AF). AF ablation certainly reduces electrically contiguous atrial mass, but this is not widely accepted to be an important part of its mechanism of action. In this article, we review data showing that atrial size is correlated in many settings with AF propensity. Larger mammals are more likely to exhibit AF. This is seen both in the natural world and in animal models, where it is much easier to create a goat model than a mouse model of AF, for example. This also extends to humans-athletes, taller people, and obese individuals all have large atria and are more likely to exhibit AF. Within an individual, risk factors such as hypertension, valvular disease and ischaemia can enlarge the atrium and increase the risk of AF. With respect to AF ablation, we explore how variations in ablation strategy and the relative effectiveness of these strategies may suggest that a reduction in electrical atrial mass is an important mechanism of action. We counter this with examples in which there is no doubt that mass reduction is less important than competing theories such as ganglionated plexus ablation. We conclude that, when considering future strategies for the ablative therapy of AF, it is important not to discount the possibility that contiguous electrical mass reduction is the most important mechanism despite the disappointing consequence being that enhancing success rates in AF ablation may involve greater tissue destruction.

Case Report: The Cox-Maze IV Procedure in the Mirror: The Use of Three-Dimensional Printing for Pre-operative Planning in a Patient With Situs Inversus Dextrocardia

The safety and efficacy of the Cox-Maze IV procedure (CMP-IV) for situs inversus dextrocardia patients with atrial fibrillation is yet to be determined. Herein, we present the case of a 39-year-old male patient admitted to our cardiac center following progressive exertional dyspnea. The patient was diagnosed with situs inversus dextrocardia, severe mitral regurgitation, and paroxysmal atrial fibrillation. A three-dimensional (3D) heart model printing device embedded with designated ablation lines was used for pre-operative planning. Mitral valvuloplasty, CMP-IV, and tricuspid annuloplasty were performed. The patient had an uneventful recovery and was in sinus rhythm during a 12-month follow-up period using a 24-h Holter monitoring device. The case herein is one of the first to report on adopting the CMP-IV procedure for situs inversus dextrocardia patients with complex valvuloplasty operation. In addition, the 3D printing technique enabled us to practice the Cox-maze IV procedure, given the patient's unique cardiac anatomy.

The occurrence and risk factors of bradycardia after the Maze procedure in patients with atrial fibrillation and tricuspid regurgitation

Objective

To evaluate the occurrence and risk factors of bradycardia after the Maze procedure in patients with atrial fibrillation and tricuspid regurgitation.

Methods

All patients underwent mitral valve (MV) replacement and concomitant bi-atrial cut-and-sew Maze procedure along with other cardiac surgical procedures were recruited from the Department of Cardiovascular Surgery at the First Affiliated Hospital of Medical College of Xi'an Jiaotong University. According to the severity of tricuspid regurgitation, all patients were divided into mild tricuspid regurgitation group and moderate-to-severe tricuspid regurgitation group. The general clinical data, biochemical indexes, intraoperative and postoperative data were collected. The relationship between tricuspid regurgitation and sinus bradycardia after the Maze procedure was analyzed by multivariate logistic regression model.

Results

We enrolled 82 patients, including 24 males and 58 females. The patients had an average age of 56 ± 10 years old. There were 50 cases in mild tricuspid regurgitation group and 32 cases in moderate-to-severe tricuspid regurgitation group. Compared with the mild tricuspid regurgitation group, postoperative bradyarrhythmia (41% vs. 14%), pre-discharge bradyarrhythmia (63% vs. 14%), postoperative sinus bradycardia (34% vs. 10%) and pre-discharge sinus bradycardia (63% vs. 10%) in moderate-to-severe tricuspid regurgitation group were significantly increased (P < 0.01). In moderate-to-severe tricuspid regurgitation, the risk of sinus bradycardia increased after the Maze procedure (OR = 1.453, 95% CI 1.127–1.874), area under ROC curve was 0.81, the Jordan index was 0.665.

Conclusion

The severity of tricuspid regurgitation may be an important factor affecting sinus bradycardia after the Maze procedure. It can be considered as a factor to predict sinus bradycardia after the Maze procedure.

The German CArdioSurgEry Atrial Fibrillation Registry: In-Hospital Outcomes

BACKGROUND

 The aim of this study was to describe outcomes of patients undergoing surgical ablation for atrial fibrillation (AF) as either stand-alone or concomitant cardiosurgical procedures in Germany.

METHODS

 Patients with AF undergoing concomitant or stand-alone surgical ablation were included in the registry. Cardiac surgery centers across Germany were invited to participate and sought to enroll 1,000 consecutive patients. Data was obtained through electronic case report forms. The protocol mandated follow-up interviews at 1 year.

RESULTS

 Between January 2017 and April 2020, 17 centers enrolled 1,000 consecutive patients. Among concomitant surgical patients (n = 899), paroxysmal AF was reported in 55.4% patients. Epicardial radio frequency (RF) bilateral pulmonary vein isolation (PVI) with excision of the left atrial appendage (LAA) was the most common operative strategy. In the stand-alone cohort (n = 101), persistent AF forms were reported in 84.1% of patients. Moderate-to-severe symptoms were reported in 85.1%. Sixty-seven patients had previously underwent at least two failed catheter ablative procedures. Thoracoscopic epicardial RF bilateral PVI and completion of a "box-lesion" with LAA closure were frequently preformed. Major cardiac and cerebrovascular complications occurred in 38 patients (4.3%) in the concomitant group. No deaths were reported in the stand-alone group. At discharge, sinus rhythm was achieved in 88.1% of stand-alone and 63.4% concomitant patients.

CONCLUSION

 The CArdioSurgEry Atrial Fibrillation registry provides insights into surgical strategies for AF ablation in a considerable cohort across Germany. This in-hospital data demonstrates that concomitant and stand-alone ablation during cardiac surgery is safe and effective with low complication rates.

Impact of Obesity on Atrial Fibrillation Recurrence Following Stand-Alone Cox Maze IV Procedure

OBJECTIVE

Obesity is a strong and independent factor for the development of atrial fibrillation (AF), and adversely impacts the success of catheter ablation procedures for AF. This study evaluated the impact of body mass index (BMI) on the outcomes following surgical ablation of AF.

METHODS

Between 2003 and 2019, 236 patients underwent a stand-alone biatrial Cox maze IV procedure (CMP-IV) for refractory AF. Obesity was defined as BMI ≥30 kg/m². Patients were divided into two groups: BMI <30 kg/m² (n = 100) and BMI ≥30 kg/m² (n = 136). Freedom from atrial tachyarrhythmia (ATA) was determined using electrocardiography, Holter, or pacemaker interrogation at 1 year and annually thereafter. Recurrence was defined as any documented ATA lasting ≥30 s. Predictors of recurrence were determined using multivariable logistic regression. Preoperative and procedural outcomes were compared between groups.

RESULTS

Obese patients had a higher rate of diabetes (16% vs 7%, P = 0.044) and larger left atrial diameter (4.9 ± 1.1 cm vs 4.6 ± 1.0 cm, P = 0.021) when compared to non-obese patients. There was no difference in major complication rate between the groups (4% vs 7%, P = 0.389). There was no operative mortality in either group. During 4.1 ± 2.4 years of follow-up, there was no significant difference in freedom from ATA with or without antiarrhythmic drugs in obese patients when compared to the non-obese group (P > 0.05). Absence of sinus rhythm at discharge predicted AF recurrence up to 7 years postoperatively.

CONCLUSIONS

As opposed to catheter ablation, obesity did not adversely impact the short and long-term outcomes of stand-alone surgical ablation with CMP-IV, and BMI was not a predictor of AF recurrence. Additionally, there was no significant increase in major complications in obese patients.

Efficacy of the stand-alone Cox-Maze IV procedure in patients with longstanding persistent atrial fibrillation

INTRODUCTION

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, and results in significant morbidity and mortality. The Cox-Maze IV procedure (CMP-IV) has been shown to have excellent efficacy in returning patients to sinus rhythm, but there have been few reports of late follow-up in sizable cohorts of patients with longstanding persistent AF, the most difficult type of AF to treat.

METHODS AND RESULTS

Between May 2003 and March 2020, 174 consecutive patients underwent a stand-alone CMP-IV for longstanding persistent AF. Rhythm outcome was assessed postoperatively for up to 10 years, primarily via prolonged monitoring (Holter monitor, pacemaker interrogation, or implantable loop recorder). Fine-Gray regression was used to investigate factors associated with atrial tachyarrhythmia (ATA) recurrence, with death as a competing risk. Median duration of preoperative AF was 7.8 years (interquartile range: 4.0-12.0 years), with 71% (124/174) having failed at least one prior catheter-based ablation. There were no 30-day mortalities. Freedom from ATAs was 94% (120/128), 83% (53/64), and 88% (35/40) at 1, 5, and 7 years, respectively. On regression analysis, preoperative AF duration and early postoperative ATAs were associated with late ATAs recurrence.

CONCLUSION

Despite the majority of patients having a long-duration of preoperative AF and having failed at least one catheter-based ablation, the stand-alone CMP-IV had excellent late efficacy in patients with longstanding persistent AF, with low morbidity and no mortality. We recommend consideration of stand-alone CMP-IV for patients with longstanding persistent AF who have failed or are poor candidates for catheter ablation.

Late results after stand-alone surgical ablation for atrial fibrillation

OBJECTIVES

Stand-alone surgical ablation of atrial fibrillation is indicated in patients with refractory atrial fibrillation who have failed medical or catheter-based ablation. Few reports of late outcomes after stand-alone surgical ablation exist using comprehensive follow-up with strict definitions of success. This study examined our late outcomes of the stand-alone Cox-Maze IV procedure.

METHODS

Between January 2003 and December 2019, 236 patients underwent a stand-alone Cox-Maze IV for refractory atrial fibrillation. Freedom from atrial tachyarrhythmias was assessed by electrocardiography, Holter, or pacemaker interrogation for up to 10 years, with a mean follow-up of 4.8 ± 3.5 years. Rhythm outcomes were compared in multiple subgroups. Factors associated with recurrence were determined using Fine-Gray regression, allowing for death as the competing risk.

RESULTS

The majority of patients (176/236, 75%) had nonparoxysmal atrial fibrillation. Median duration of preoperative atrial fibrillation was 6.2 years (interquartile range, 3-11). Fifty-nine percent of patients (140/236) failed 1 or more prior catheter-based ablation. Thirteen patients (6%) experienced a major complication. There was no 30-day mortality. Freedom from atrial tachyarrhythmias was 94% (187/199), 89% (81/91), and 77% (24/31) at 1, 5, and 10 years, respectively. There was no difference in freedom from atrial tachyarrhythmias between patients with paroxysmal atrial fibrillation versus nonparoxysmal atrial fibrillation (P > .05) or those undergoing sternotomy versus a minimally invasive approach (P > .05). Increased left atrial size and number of catheter ablations were associated with late atrial fibrillation recurrence. For patients who experienced any atrial tachyarrhythmia recurrence, the median number of recurrences was 1.5 (1.0-3.0).

CONCLUSIONS

The stand-alone Cox-Maze IV had excellent late efficacy at maintaining sinus rhythm in patients with symptomatic, refractory atrial fibrillation, with low morbidity and no mortality. The Cox-Maze IV, in contrast to catheter-based ablation, was equally effective in patients with paroxysmal and nonparoxysmal atrial fibrillation.

Concomitant Cox-Maze IV and Septal Myectomy in Patients With Hypertrophic Obstructive Cardiomyopathy

BACKGROUND

In patients with hypertrophic obstructive cardiomyopathy, atrial fibrillation is associated with heart failure and increased late mortality. However, the role of surgical ablation in these patients is not well defined. The aim of this study was to evaluate the efficacy of the concomitant Cox-Maze IV procedure in patients undergoing septal myectomy for hypertrophic obstructive cardiomyopathy.

METHODS

Between 2005 and 2019, 347 patients who underwent septal myectomy at a single institution (Washington University School of Medicine, Barnes-Jewish Hospital, St Louis, MO) were retrospectively reviewed. For patients with hypertrophic obstructive cardiomyopathy and atrial fibrillation who underwent a concomitant Cox-Maze IV procedure, freedom from atrial tachyarrhythmias (ATAs) on or off antiarrhythmic drugs (AADs) was evaluated annually. Predictors of ATA recurrence were identified using Fine-Gray regression, with death as a competing risk.

RESULTS

A total of 42 patients underwent concomitant septal myectomy and Cox-Maze IV procedures. The majority of patients, 69% (29 of 42), had paroxysmal atrial fibrillation with a 2.5-year median duration. Operative mortality was 7% (3 of 42). New York Heart Association functional class was reduced after surgery (P < .01). Rates of freedom from recurrent ATAs at 1- and 5-year intervals were 93% (27 of 29) and 100% (14 of 14), respectively. Rates of freedom from ATAs and AADs were 83% (24 of 29) and 100% (14 of 14) at the same time points, respectively. Increased left atrial diameter predicted first ATA recurrence (P < .01). Cerebrovascular accident risk was lower in patients with atrial fibrillation who underwent concomitant Cox-Maze IV and septal myectomy relative to myectomy only (P = .02).

CONCLUSIONS

Late freedom from ATAs on or off AADs was excellent after Cox-Maze IV and septal myectomy. Although there was a higher than expected rate of perioperative complications, the study results suggest that concomitant surgical ablation should be considered in selected patients with hypertrophic obstructive cardiomyopathy and atrial fibrillation.

Biparietal bidirectional bipolar radiofrequency in hybrid cardiac ablation: an in vitro evaluation

 

OBJECTIVES

The aim of this study was to evaluate the lesion size and depth of radiofrequency (RF) ablation in a simultaneous biparietal bidirectional bipolar (SBB) approach, compared to a simultaneous and staged unipolar and uniparietal bipolar setup [simultaneous uniparietal bipolar (SiUB) and staged uniparietal bipolar (StUB), respectively].

METHODS

Fresh left atrial porcine tissue was mounted into the ABLA-BOX simulator. Different ablation approaches were tested: (i) SBB: a concept consisting of SBB endo-epicardial ablation, (ii) SiUB: simultaneous epicardial uniparietal bipolar and endocardial unipolar ablation and (iii) StUB: staged epicardial uniparietal bipolar and endocardial unipolar ablation. In the StUB setup, a 1-h interval between the epi-endo ablation was respected.

RESULTS

Transmural lesions were present in 90% of the bipolar biparietal ablations, yet no full transmurality was observed in the simultaneous nor in the staged unipolar with uniparietal bipolar ablation group. In SBB, the area and volume of the ablation lesions were smaller (523.33 mm2/mm and 52.33 mm3/mm, respectively) than in SiUB (588.17 mm2/mm and 58.81 mm3/mm, respectively) and StUB (583.76 mm2/mm and 58.37 mm3/mm, P = 0.044). Also, in SBB, the overall, epicardial and endocardial maximum diameters of the lesions (1.59, 1.57 and 1.52 mm; respectively) were smaller than in SiUB (2.38, 2.26 and 2.33 mm; respectively) and in StUB (2.36, 2.28 and 2.14 mm; respectively, all P < 0.001).

CONCLUSIONS

Although bipolar biparietal bidirectional RF ablation results in smaller lesions than uniparietal bipolar and unipolar ablation, their capacity to penetrate the tissue is much higher. Moreover, in uniparietal RF applications, the energy spreads in the superficial layers of the tissue but fails to penetrate. Therefore, the degree of transmurality is much higher when using such a 'truly bipolar' ablation approach.

New Biparietal Bipolar Catheter Prototype for Hybrid Atrial Fibrillation Ablation

Objective

To evaluate the size and depth of linear lesions by in vitro testing with a custom-made radio frequency biparietal bipolar ablation catheter in a single-stage setting.

Methods

A custom-made catheter was created to generate linear lesions around the left atrium and pulmonary veins of an ex vivo pig. Two frames were made, 1 epicardial and 1 endocardial. A continuous copper braid electrode and an alignment system consisting of 2 parallel rows of neodymium magnets were embedded in a flexible plastic support. After 24 hours of formalin conservation, samples of the left atrium of a freshly slaughtered pig were sliced in a cryotome, thus obtaining a sequence of 100-µm thick layers extending from the endocardial to the epicardial side. After being digitized through a scanner, these layers were evaluated using morphometric computer software. For each slice, we evaluated the maximum length of the lesions, the maximum epicardial length, the maximum endocardial length, the total area of the lesion, and the total volume.

Results

Forty transmural lesions from 40 specimens were obtained. The results were the following (the number in parenthesis is the interquartile range in mm): lesion maximum length (L_MAX) was 7.297 mm (0.006), epicardial maximum length (L_EPI) was 7.291 mm (0.014), and endocardial maximum length was 7.291 mm (0.018). The total area and total volume were 1018.50 ± 36.51 mm² and 101.85 ± 3.65 mm³, respectively.

Conclusions

Our prototype showed very promising results. The next step will be to enhance the design for clinical application.

The Impact of the Cox-Maze Technique on Freedom From Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) is the most common arrhythmia observed with concomitant cardiac surgery. Surgical options include a cut-and-sew technique Maze (CAS) and a cryoablation/bipolar technique Maze (CB). There are limited data comparing the long-term outcomes of these 2 techniques.

METHODS

All patients who underwent either CAS or CB Maze between 2011 and 2018 were included in the study. Chi-square test and Fisher's exact test or Student's t test were used to compare differences between baseline characteristics. Kaplan-Meier survival curves were generated for each group. Cumulative incidence functions were generated for AF recurrence and Fine-Gray competing-risk regression was used to determine predictors for AF recurrence.

RESULTS

A total of 482 patients underwent open surgical ablation. Of those, 287 had CAS and 198 had CB. All procedures were concomitant with cardiac surgery. There was similar long-term mortality between the CAS and CB cohorts (22.3% vs 17.4%; log-rank P = .91). There was no difference in pacemaker implantation (11.1% vs 11.3%; P = .813) or long-term freedom from AF recurrence (73.3% vs 78.2%; P = .294). On Fine-Gray competing-risk regression, New York Heart Association functional class IV (hazard ratio [HR], 2.07; P = .03), concomitant aortic valve replacement (HR, 3.02; P = .01), and concomitant CABG + valve (HR, 2.36; P = .02) were significant independent predictors for AF recurrence; Maze type was not a predictor.

CONCLUSIONS

These data indicate no difference between the CAS vs CB with respect to freedom from long-term AF. Both techniques may be appropriate based on surgeon experience and patient characteristics.

A safe and secure approach for creating a box lesion in the left atrium

A bipolar radiofrequency clamp is an attractive alternative to the cut-and-sew technique for surgical ablation of atrial fibrillation. We have been using this device for isolating the posterior left atrium. However, there is a risk of disconnection of the ablation lines as well as perforation of the left atrium by the tip of the radiofrequency clamp. Here, we report our simple contrivance to make the procedure more secure and safe.

Outcomes of Atrial Arrhythmia Surgery in Patients With Congenital Heart Disease: A Systematic Review

Background The improved life expectancy of patients with congenital heart disease is often accompanied by the development of atrial tachyarrhythmias. Similarly, the number of patients requiring redo operations is expected to continue to rise as these patients are aging. Consequently, the role of arrhythmia surgery in the treatment of atrial arrhythmias is likely to become more important in this population. Although atrial arrhythmia surgery is a well-established part of Fontan conversion procedures, evidence-based recommendations for arrhythmia surgery for macroreentrant atrial tachycardia and atrial fibrillation in other patients with congenital heart disease are still lacking. Methods and Results Twenty-eight studies were included in this systematic review. The median reported arrhythmia recurrence was 13% (interquartile range, 4%-26%) during follow-up ranging from 3 months to 15.2 years. A large variation in surgical techniques was observed. Based on the acquired data, biatrial lesions are more effective in the treatment of atrial fibrillation than exclusive right-sided lesions. Right-sided lesions may be more appropriate in the treatment of macroreentrant atrial tachycardia; evidence for the superiority of additional left-sided lesions is lacking. There are not enough data to support the use of exclusive left-sided lesions. Theoretically, prophylactic atrial arrhythmia surgery may be beneficial in this population, but evidence is currently limited. Conclusions To be able to provide recommendations for arrhythmia surgery in patients with congenital heart disease, future studies should report outcomes according to the type of preoperative arrhythmia, underlying congenital heart disease, lesion set, and energy source. This is essential for determining which surgical techniques should ideally be applied under which circumstances.

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.