The Cox-maze IV procedure in its second decade: still the gold standard?

High incidence of permanent pacemaker after Cox-maze IV and mitral valve surgery: a nationwide registry-based study

OBJECTIVES

This study evaluated the long-term risk of permanent pacemaker implantation following Cox-maze IV (CMIV) and concurrent mitral valve surgery.

METHODS

A retrospective, nationwide, registry-based analysis was conducted on postoperative permanent pacemaker implantation in 397 patients with symptomatic mitral valve insufficiency and atrial fibrillation who underwent CMIV and mitral valve surgery in Sweden between 2009 and 2017. They were compared to a registry group of 346 patients with atrial fibrillation who underwent mitral valve surgery without surgical ablation during 2014-2017. The follow-up ended on 30 September 2022.

RESULTS

CMIV patients were on average 4 years younger and had lower surgical risk than registry patients. More CMIV patients underwent early (<30 days) pacemaker implantation (13.3% vs. 5.5%, P = 0.002). CMIV patients had a doubled adjusted risk of requiring a pacemaker compared to registry patients after 8 years [HR 1.96, 95% CI 1.27-3.04]. In the CMIV group, 22% (95% CI 18-26%) had a pacemaker by 5 years, increasing to 27% (95% CI 22-31%) by 8 years, compared to 13% (95% CI 10-17%) at both time intervals in the registry group. Atrioventricular block II/III accounted for >60% of early pacemaker indications in both groups, and sinus node dysfunction was the indication for late pacemaker implantation in 48% in the CMIV group.

CONCLUSIONS

Patients undergoing CMIV concomitant with mitral valve surgery have a higher rate of postoperative pacemaker implantation compared to patients with atrial fibrillation undergoing mitral valve surgery alone. Sinus node dysfunction was the main indication for late pacemaker among CMIV patients.

The cardioprotective effects of HTK solution and conventional blood cardioplegia in patients with atrial fibrillation undergoing valvular replacement and Cox maze III procedure

INTRODUCTION

The study was to assess the myocardial protection effects of the histidine-tryptophan-ketoglutarate (HTK) solution and the 4:1 blood cardioplegia (BC) in patients with atrial fibrillation (AF) who were subjected to valvular replacement concomitant with the Cox maze III surgery.

METHODS

A cohort of 148 individuals afflicted with AF, who received valve replacement surgery in conjunction with the Cox maze III procedure at our clinic within the period extending from 2015 to 2023, were enrolled. Subsequent to adjustment by propensity score matching (PSM), the patients were categorized into two distinct groups: the HTK group and the BC group. The primary end points assessed inotropic support requirements, complications, troponin trend, mechanical ventilation time and the intensive care unit stay. Arrhythmias, aortic cross-clamp and cardiopulmonary bypass times, and other clinical perioperative variables were considered as secondary end points.

RESULTS

No substantive disparities were observed concerning mortality rates, arrhythmias, neurological events, or renal complications. The duration of cardiopulmonary bypass and the aortic cross-clamp time did not demonstrate any marked variations between both groups, with p-values of 0.71 and 0.05, respectively. The time required for weaning from mechanical ventilation and the length of postoperative hospitalization were notably less in the group receiving HTK solution (p < 0.001 and p = 0.03, respectively). While inotropic support need was higher in the BC group (p = 0.02). Conversely, the dosage and frequency of perfusions were considerably increased in the BC group (p < 0.001 for each parameter). Within subgroups stratified by longer than 150 min of aortic cross-clamping duration, those in the BC cohort had significantly elevated peaks of cardiac troponin I (cTnI) (p = 0.01), whereas individuals in the HTK group experienced less mechanical ventilation time (p = 0.002) and shorter durations of intensive care unit admission (p < 0.001). The LVEF value in the HTK group was higher compared to that in the BC group in the 3-month follow-up data (p = 0.02).

CONCLUSIONS

Both the HTK and 4:1 blood cardioplegia could be used safely in patients with AF who were subject to valvular replacement and Cox maze III procedure. However, the utilization of HTK conferred a greater advantage in diminishing the duration of mechanical ventilation weaning and the duration of postoperative hospitalization. HTK may be a better myocardial protection in patients with long cross-clamp time. The follow-up data indicated that HTK might be superior to 4:1 blood cardioplegia in the short-medium term cardiac function.

Risk of neurologic events after surgery for mitral valve insufficiency and concomitant Cox-maze IV procedure for atrial fibrillation. A nationwide register-based study

OBJECTIVES

Analysis of the long-term risks of ischaemic stroke and cerebral bleeding in patients with atrial fibrillation after mitral valve surgery and concomitant Cox-maze IV procedure.

METHODS

In total, 397 patients with symptomatic degenerative mitral valve insuffciency and atrial fibrillation, underwent mitral valve surgery and Cox-maze IV in Sweden between 2009 and 2017. In this retrospective nationwide analysis, patients were followed in national patient registers until 30 September 2022.

RESULTS

There were 4 deaths within 30 days (1.0%). Mean follow-up was 8.7 (0.1-13.4) years. Survival without ischaemic stroke or cerebral haemorrhage at 5 and 10 years were 90% and 74%, respectively. Nineteen patients experienced an ischaemic stroke, of which 4 were fatal. Five of 34 patients (14.7%) with a history of stroke preoperatively experienced ischaemic stroke during follow-up. The linearized rate of ischaemic stroke per patient-year was 0.6% and was similar regardless of left atrial appendage closure during surgery or whether a mechanical valve was inserted. The observed ischaemic stroke rate was lower than the predicted rate for all CHA2DS2-VASc score groups. Fourteen patients suffered cerebral bleeding, of which 3 were fatal. Patients who experienced cerebral bleeding were older and had higher mechanical valve implantation rate than those without cerebral bleeding.

CONCLUSIONS

Surgery for mitral valve insufficiency and concomitant Cox-maze IV can be performed with low perioperative risk. There is a low continuing risk of stroke long-term postoperatively that correlates with a higher CHA2DS2-VASc score. Patients with preoperative stroke are at increased risk of postoperative stroke despite atrial fibrillation surgery.

Atrial Fibrillation Surgery in Australia: Are We Doing Enough?

AIM

This study aimed to examine contemporary burden and treatment trends of atrial fibrillation (AF) in patients undergoing cardiac surgery in Australia and New Zealand. This allows comparison of contemporary practice with the Society of Thoracic Surgeons guideline recommendations for the surgical treatment of AF in patients undergoing cardiac surgery.

METHOD

A 10-year retrospective review of the Australian & New Zealand Society of Cardiac & Thoracic Surgeons National Cardiac Surgery Database was performed, examining all adult cardiac surgery patients from 2011 to 2021. Patients were grouped by the presence or absence of AF, and simple descriptive statistical analysis was performed to assess baseline demographics and premorbid condition of the patients. The incidence of AF was analysed by type of surgery. Trends for surgical treatment of AF were then analysed using simple descriptive statistics, examining isolated left atrial appendage ligation, isolated surgical ablation, and combined ligation and ablation.

RESULTS

In the last 10 years, the Australian & New Zealand Society of Cardiac & Thoracic Surgeons database has recorded 140,680 patients who underwent cardiac surgery. Atrial fibrillation (AF) was present in 21,077 patients (14%). Patients with AF were generally older (72.25 vs 66.65 years; p<0.001). Among patients undergoing cardiac surgery, AF was more common in female than in male patients (18% vs 13%, respectively). Patients with AF more often had a higher classification of dyspnoea according to the New York Heart Association and lower ejection fractions compared with their AF-free counterparts. The incidence of AF as a comorbid condition was more frequent in patients undergoing mitral valve surgery or combined coronary artery bypass grafting and valve surgery (aortic, mitral, or both) compared with those undergoing isolated coronary or aortic surgery. Only 11.90% (n=2,509) of patients with AF received a combined ablation and left atrial appendage ligation, and 19.54% (n=693) of those received a Cox-Maze IV ablation.

CONCLUSIONS

The burden of concomitant AF in patients undergoing cardiac surgery in Australia is higher than previously reported (14% vs 5%-11%). Despite strong recommendation for the surgical management of AF in patients undergoing cardiac surgery and clear evidence of its benefit, both left atrial appendage ligation and surgical ablation independently or concomitantly remain heavily underutilised in this cohort.

Tailored bi-atrial linear ablation guided by electrophysiological mapping for persistent atrial fibrillation

AIM

To explore the safety and efficacy of a novel strategy (bi-atrial linear catheter ablation guided by electrophysiological mapping) for persistent atrial fibrillation (PeAF) treatment.

METHODS

83 patients with PeAF were enrolled for evaluation of ablation strategy. 43 patients were subjected to pulmonary vein isolation (PVI) strategy (PVI group). 40 patients were subjected to bi-atrial linear ablation strategy guided by electrophysiological mapping (PVI, left atrial BOX ablation, coronary sinus endocardial linear ablation, tailored left atrial anterior wall linear ablation, mitral isthmus linear ablation with necessary ethanol infusion into the vein of Marshall, right atrial posterior wall linear ablation and cavo-tricuspid isthmus ablation) (linear ablation group). Patients were followed up every 3 months.

RESULTS

During a median follow-up of 12 (4-16) months, freedom from atrial fibrillation/atrial tachycardia recurrence was 87.5% in the linear ablation group and 65.1% in the PVI group (P < 0.01). A Cox regression multivariate analysis revealed that ablation strategy group (tailored bi-atrial linear ablation) (HR 0.33, 95% CI 0.12-0.91, P = 0.03) was the only independent predictor of recurrence.

CONCLUSION

Tailored bi-atrial linear ablation strategy guided by electrophysiological mapping resulted in improved outcomes without compromising safety for patients with PeAF.

Outcomes of surgical ablation for atrial fibrillation in on- versus off-pump coronary artery bypass grafting

OBJECTIVES

A considerable number of patients undergoing coronary artery bypass grafting surgery suffer from atrial fibrillation and should be treated concomitantly. This manuscript evaluates the impact of on-pump versus off-pump bypass grafting on the applied lesion set and rhythm outcome.

METHODS

Between January 2017 and April 2020, patients who underwent combined bypass grafting and surgical ablation for atrial fibrillation were consecutively enrolled in the German CArdioSurgEry Atrial Fibrillation registry (CASE-AF, 17 centres). Data were prospectively collected. Follow-up was planned after one year.

RESULTS

A total of 224 patients were enrolled. No differences in baseline characteristics were seen between on- and off-pump bypass grafting, especially not in type of atrial fibrillation and left atrial size. In the on-pump group (n = 171, 76%), pulmonary vein isolation and an extended left atrial lesion set were performed more often compared to off-pump bypass grafting (58% vs 26%, 33 vs 9%, respectively, P < 0.001). In off-pump bypass grafting a box isolating the atrial posterior wall was the dominant lesion (72% off-pump vs 42% on-pump, P < 0.001). Left atrial appendage management was comparable in on-pump versus off-pump bypass grafting (94% vs 91%, P = 0.37). Sinus rhythm at follow-up was confirmed in 61% in the on-pump group and in 65% in the off-pump group (P = 0.66). No differences were seen in in-hospital or follow-up complication-rates between the two groups.

CONCLUSIONS

In coronary artery bypass grafting patients undergoing concomitant atrial fibrillation ablation, our data suggests that the technique applied for myocardial revascularization (off-pump vs on-pump) leads to differences in the ablation lesion set, but not in safety and effectiveness.

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

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

Computational modeling of cardiac electrophysiology and arrhythmogenesis: toward clinical translation

The complexity of cardiac electrophysiology, involving dynamic changes in numerous components across multiple spatial (from ion channel to organ) and temporal (from milliseconds to days) scales, makes an intuitive or empirical analysis of cardiac arrhythmogenesis challenging. Multiscale mechanistic computational models of cardiac electrophysiology provide precise control over individual parameters, and their reproducibility enables a thorough assessment of arrhythmia mechanisms. This review provides a comprehensive analysis of models of cardiac electrophysiology and arrhythmias, from the single cell to the organ level, and how they can be leveraged to better understand rhythm disorders in cardiac disease and to improve heart patient care. Key issues related to model development based on experimental data are discussed, and major families of human cardiomyocyte models and their applications are highlighted. An overview of organ-level computational modeling of cardiac electrophysiology and its clinical applications in personalized arrhythmia risk assessment and patient-specific therapy of atrial and ventricular arrhythmias is provided. The advancements presented here highlight how patient-specific computational models of the heart reconstructed from patient data have achieved success in predicting risk of sudden cardiac death and guiding optimal treatments of heart rhythm disorders. Finally, an outlook toward potential future advances, including the combination of mechanistic modeling and machine learning/artificial intelligence, is provided. As the field of cardiology is embarking on a journey toward precision medicine, personalized modeling of the heart is expected to become a key technology to guide pharmaceutical therapy, deployment of devices, and surgical interventions.

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.

Comparison of short-term efficacy of two bipolar radiofrequency ablation forceps for rheumatic heart disease concomitant with atrial fibrillation

Background

Currently, the bipolar radiofrequency ablation forceps manufactured by AtriCure are the main instrument for surgical ablation in patients with rheumatic heart disease (RHD) concomitant with atrial fibrillation (AF). The bipolar radiofrequency ablation forceps by Med-Zenith has a greater advantage in price compared with AtriCure. However, few studies have been reported on the comparison of their clinical efficacy. The aim of this study is to compare the short-term clinical efficacy of the two ablation forceps for RHD concomitant with AF.

Methods

Clinical data of 167 patients with RHD concomitant with AF admitted to the Department of Cardiac Major Vascular Surgery, Affiliated Hospital of North Sichuan Medical College, were retrospectively analyzed, and the restoration efficacy of sinus rhythm (SR) and cardiac function after surgery were compared with two ablation forceps.

Results

The end-systolic diameter of the right atrium and the end-systolic diameter of the left atrium in the patients of both groups at each postoperative time point decreased compared with that of the preoperative period (P < 0.05), and the left ventricular ejection fraction started to improve significantly at 6 months after surgery compared with that of the preoperative period (P < 0.05). There was no difference between the two groups of patients in the comparison of the aforementioned indicators at different points in time (P > 0.05). At 12 months postoperatively, the SR maintenance rate in using the ablation forceps by Med-Zenith (73.3%) was lower than that for AtriCure (86.4%) and the cumulative recurrence rate of AF in using the Med-Zenith ablation forceps was greater than that for AtriCure.

Conclusions

The two bipolar radiofrequency ablation forceps compared in the study are safe and effective in treating patients of RHD concomitant with AF, and the ablation forceps by AtriCure may be more effective in restoring SR in the short term.

Performance of a non-irrigated bipolar radiofrequency ablation clamp on beating human hearts

OBJECTIVE

This study is intended to examine the efficacy of a non-irrigated bipolar RF clamp and explore the factors that can influence its performance on beating human hearts using the electrophysiology mapping method.

METHODS

A total of 83 atrial fibrillation (AF) patients were included in this study. Based on the Body mass index (BMI, kg/m2), the AF patients were divided into the normal group (18.5 ≤ BMI < 25) and the overweight or obese group (BMI ≥ 25). They all underwent a stand-alone surgical ablation through our off-pump biatrial mini-maze procedure. After we completed each time of ablation, the achievement of PV isolation was checked using the electrophysiology mapping method. The number of ablation times to achieve the PV isolation on the left and right PVs was recorded respectively.

RESULTS

86.7% (72/83) PV isolation on the LPV and 72.3% (60/83) PV isolation on the RPV could be achieved respectively after performing a single time of surgical ablation. Three times of ablations resulted in 100.0% PV isolation on the left and right PVs. In the normal BMI group, the ratio of patients who achieved a complete PV isolation after a single time of ablation was 83.7% (36/43), which was higher than the 60.0% (24/40) in the overweight or obese group.

CONCLUSIONS

Performing three times of ablations resulted in 100% PV isolation on the left and right PVs. The bipolar RF clamp had a better performance on the LPV than on the RPV. The patients' BMI also influenced the Atricure clamp' s performance.

Surgical ablation for atrial fibrillation is efficacious in patients with giant left atria

OBJECTIVE

The Cox-Maze IV procedure (CMP-IV) is the most effective treatment for atrial fibrillation. Increased left atrial (LA) size has been identified as a risk factor for failure to restore sinus rhythm. This has biased many surgeons against ablation in patients with giant left atrium (GLA), defined as LA diameter >6.5 cm. In this study we aimed to define the efficacy of the CMP-IV in patients with GLA.

METHODS

From April 2004 through March 2020, 786 patients with a documented LA diameter underwent elective CMP-IV, 72 of whom had GLA. Median follow-up duration was 4 years (interquartile range, 1-7 years). Recurrence was defined as any documented atrial tachyarrhythmia (ATA) lasting 30 seconds. ATA recurrence and survival were analyzed across GLA versus non-GLA groups.

RESULTS

Median age at surgery was 65 (interquartile range, 56-73) years. Median LA diameter within the GLA group was 7.0 (range, 6.6-10.0) cm. There were no differences in rates of postoperative complications for the 2 groups, including rate of postoperative stroke and pacemaker placement (GLA 14%; non-GLA 12%; P = .682). A trend toward increased 30-day mortality in the GLA group did not reach statistical significance (GLA 6%; non-GLA 2%; P = .051). Freedom from ATAs at 5 years postoperatively was comparable for the 2 groups (GLA 82%; non-GLA 84%).

CONCLUSIONS

The CMP-IV had good efficacy in patients with GLA. Our results suggest that LA diameter >6.5 cm should not preclude a patient from undergoing surgical ablation for atrial fibrillation.

Surgical ablation of atrial fibrillation during mitral valve surgery: a systematic review and meta-analysis

Background

Atrial fibrillation (AF) is a common tachyarrhythmia, affecting approximately 33 million people worldwide, and is frequently associated with mitral valve disease. Surgical ablation during mitral valve surgery provides an opportune circumstance for arrhythmia correction. The results of recent randomized trial data are promising, demonstrating both safety and efficacy. The aim of this systematic review is to report the efficacy and morbidity of concomitant surgical ablation for AF during mitral valve surgery.

Methods

Five electronic databases were searched from inception to March 2023. All studies reporting the primary outcome, freedom from AF (FFAF), for patients with a history of AF undergoing concomitant mitral valve surgery were identified. Studies with patient cohorts less than 100 were excluded. Relevant data were extracted and a meta-analysis of proportions was conducted using a random-effects model. Survival data were pooled from original Kaplan-Meier curves and reconstructed, reporting aggregate FFAF and survival.

Results

Thirty-six studies with a total of 8,340 patients were included in the systematic review. All 36 papers reported postoperative FFAF with a pooled result of 76.9% [95% confidence interval (CI): 73.8-79.9%] at a weighted mean follow-up of 40.2 months, however this result was associated with significant heterogeneity (I2=89%). A total of 31 studies reported postoperative short-term mortality, with a pooled result of 1.68% (95% CI: 1.15-2.29%). Aggregate survival at 1 to 5 years was 93.7%, 92.5%, 91.3%, 89.4%, and 87%, respectively, and aggregate FFAF for 1 to 5 years was 90.2%, 83.5%, 79.5%, 76.4% and 73.2%, respectively.

Conclusions

Evaluation of the evidence suggests that concomitant ablation for AF during mitral valve surgery is both safe and efficacious. The results were associated with significant heterogeneity, reflective of variable institutional protocols, patient characteristics, and lesion sets. Randomized data with longer term follow-up would help validate these results.

Persistent atrial fibrillation without the evidence of low-voltage areas: a prospective randomized trial

BACKGROUND

An effective therapy of persistent atrial fibrillation beyond pulmonary vein isolation remains unsatisfactory. Targeting endocardial low-voltage areas represents an approach of substrate modification. This prospective, randomized study investigated the efficacy of ablation of low-voltage areas versus PVI and additional linear ablations in patients with persistent atrial fibrillation in terms of single-procedure arrhythmia-free outcome and safety.

METHODS AND RESULTS

A total number of 100 patients undergoing de-novo catheter ablation for persistent AF were randomized in a 1:1 ratio into two different treatment arms: group A: pulmonary vein isolation (PVI) and, if low-voltage areas were present, a substrate modification. Group B: PVI and, if atrial fibrillation persisted, additional ablations, such as linear ablation and/or ablation of non-PV triggers. A total of 50 patients were randomized into each group without significant differences in baseline characteristics. During a mean follow-up of 17.64 ± 4.5 months after a single procedure, 34 (68%) patients of group A were free of arrhythmia recurrence versus 28 (56%) patients in group B (p = ns). In group A, 30 (60%) patients did not show endocardial fibrosis and received solely PVI. Both procedures were performed with a low number of complications; no pericardial effusion or stroke were seen in either group.

CONCLUSIONS

A significant proportion of patients with persistent atrial fibrillation do not show low-voltage areas. A total of 70% of the patients receiving solely PVI did not show any recurrence of atrial fibrillation, and therefore, extensive additional ablation should be avoided in de-novo patients.

Trends in surgical ablation at the time of cardiac surgery among patients with atrial fibrillation

Background

The 2017 American Association for Thoracic Surgery (AATS) guidelines support surgical ablation in patients undergoing cardiac surgery with preoperative atrial fibrillation (AF) owing to a reduction in early mortality and improved overall safety. We explored practice patterns changes and outcomes in patients undergoing concomitant surgical ablation following the guideline change.

Methods

We identified 19,246 patients with preoperative AF who underwent cardiac surgery between 2016 and 2019 from the Florida and Maryland State Inpatient Databases. Rates of surgical ablation by procedure type were temporally trended across years. Secondary outcomes included complications, inpatient mortality, and hospital readmissions. Using multivariable logistic regression, we identified patient variables associated with concomitant surgical ablation.

Results

A total of 2738 patients (14.3%) with AF underwent a concomitant surgical ablation. The rate of surgical ablation increased from 2.1% to 17.4% (P < .001) from 2016 to 2017 but remained unchanged thereafter. Postoperative mortality was lower in the surgical ablation cohort (2.7% vs 3.7%; P = .006), although with a higher rate of pacemaker insertion (11.8% vs 7.2%; P < .0001). Patients with a high-risk Elixhauser score (odds ratio [OR], 0.83; 95% confidence interval [CI], 0.73-0.95), lower income (OR, 0.66; 95% CI, 0.57-0.75), or African American or Hispanic race/ethnicity (OR, 0.80; 95% CI, 0.67-0.96 and OR, 0.82; 95% CI, 0.71-0.96, respectively) had lower odds of undergoing concomitant surgical ablation.

Conclusions

Despite a class I-2a recommendation by the AATS, surgical ablation continues to be underutilized in clinical practice, especially in patients with high-risk comorbidities, with lower incomes, or from minority populations. Surgeons should be mindful of guideline-directed AF management in these vulnerable populations.

Rationale and design of a randomized trial of the dapagliflozin evaluation on atrial fibrillation patients followed Cox-Maze IV: the DETAIL-CMIV study

AIMS

Dapagliflozin has been widely used for the treatment of type 2 diabetes mellitus (T2DM) and heart failure (HF). However, data concerning the association between dapagliflozin and the recurrence of atrial fibrillation (AF), especially in patients following Cox-Maze IV (CMIV), are rare. We aim to explore the effect of dapagliflozin on the recurrence of AF after CMIV with and without T2DM or HF.

METHODS AND RESULTS

The study of dapagliflozin evaluation in AF patients followed by CMIV (DETAIL-CMIV) is a prospective, double-blind, randomized, placebo-controlled trial. A total of 240 AF patients who have received the CMIV procedure will be randomized into the dapagliflozin group (10 mg/day, n = 120) and the placebo group (10 mg/day, n = 120) and treated for 3 months. The primary endpoint is any documented atrial tachyarrhythmia (AF, atrial flutter or atrial tachycardia) lasting 30 s following a blanking period of 3 months after CMIV.

CONCLUSION

DETAIL-CMIV will determine whether the sodium-glucose cotransporter-2 inhibitor dapagliflozin, added to guideline-recommended post-operative AF therapies, safely reduces the recurrence rate of AF in patients with and without T2DM or HF.

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.

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.

Progress in atrial fibrillation ablation during 25 years of Europace journal

The first edition of Europace journal in 1999 came right around the time of the landmark publication of the electrophysiologists from Bordeaux, establishing how elimination of ectopic activity from the pulmonary veins (PVs) resulted in a marked reduction of atrial fibrillation (AF). The past 25 years have seen an incredible surge in scientific interest to develop new catheters and energy sources to optimize durability and safety of ablation, as well as study the mechanisms for AF and devise ablation strategies. While ablation in the beginning was performed with classic 4 mm tip catheters that emitted radiofrequency (RF) energy to create tissue lesions, this evolved to using irrigation and contact force (CF) measurement while increasing power. Also, so-called single-shot devices were developed with balloons and arrays to create larger contiguous lesions, and energy sources changed from RF current to cryogenic ablation and more recently pulsed field ablation with electrical current. Although PV ablation has remained the basis for every AF ablation, it was soon recognized that this was not enough to cure all patients, especially those with non-paroxysmal AF. Standardized approaches for additional ablation targets have been used but have not been satisfactory in all patients so far. This led to highly technical mapping systems that are meant to unravel the drivers for the maintenance of AF. In the following sections, the development of energies, strategies, and tools is described with a focus on the contribution of Europace to publish the outcomes of studies that were done during the past 25 years.

Performance of an Irrigated Bipolar Radiofrequency Ablation Clamp on Explanted Human Hearts

BACKGROUND

Bipolar radiofrequency (RF) clamps are commonly used during surgical ablation for atrial fibrillation (AF). This study examined the efficacy of an irrigated bipolar RF clamp to create transmural lesions in an ex vivo human heart model.

METHODS

Ten donor hearts, turned down for transplantation, were explanted and arrested with cold cardioplegia. The ablations of the Cox Maze IV procedure were performed using the Cardioblate LP (Medtronic, Inc) irrigated bipolar RF clamp. In the first 5 hearts, each lesion was created with a single application of RF, whereas in the remaining 5 hearts, each lesion was created with a double application of RF without unclamping. Each lesion was cross-sectioned and stained with 2,3,5-triphenyl-tetrazolium chloride to assess ablation depth and transmurality.

RESULTS

A total of 100 lesions were analyzed. In the single-ablation group, 222 of 260 sections (85%) and 37 of 50 lesions (74%) were transmural. The efficacy improved significantly in the double-ablation group, in which 348 of 359 sections (97%, P < .001) and 46 of 50 lesions (92%, P = .017) were transmural. Overall, in nontransmural lesions, the epicardial fat thickness was significantly greater (1.69 ± 0.70 mm vs 0.45 ±0.10 mm, P < .001) than the transmural lesions.

CONCLUSIONS

A single ablation on human atrial tissue with an irrigated bipolar RF clamp was insufficient to reliably create transmural lesions, but a double ablation significantly increased the lesion and section transmurality. Nontransmural lesions were associated with significantly thicker layers of epicardial fat, which likely decreased tissue energy delivery due to the higher resistance of fat to current flow.

Prediction model of atrial fibrillation recurrence after Cox-Maze IV procedure in patients with chronic valvular disease and atrial fibrillation based on machine learning algorithm

OBJECTIVES

Atrial fibrillation (AF) is a prevalent cardiac arrhythmia, and Cox-maze IV procedure (CMP-IV) is a commonly employed surgical technique for its treatment. Currently, the risk factors for atrial fibrillation recurrence following CMP-IV remain relatively unclear. In recent years, machine learning algorithms have demonstrated immense potential in enhancing diagnostic accuracy, predicting patient outcomes, and devising personalized treatment strategies. This study aims to evaluate the efficacy of CMP-IV on treating chronic valvular disease with AF, utilize machine learning algorithms to identify potential risk factors for AF recurrence, construct a CMP-IV postoperative AF recurrence prediction model.

METHODS

A total of 555 patients with AF combined with chronic valvular disease, who met the criteria, were enrolled from January 2012 to December 2019 from the Second Xiangya Hospital of Central South University and the Affiliated Xinqiao Hospital of the Army Medical University, with an average age of (57.95±7.96) years, including an AF recurrence group (n=117) and an AF non-recurrence group (n=438). Kaplan-Meier method was used to analyze the sinus rhythm maintenance rate, and 9 machine learning models were developed including random forest, gradient boosting decision tree (GBDT), extreme gradient boosting (XGBoost), bootstrap aggregating, logistic regression, categorical boosting (CatBoost), support vector machine, adaptive boosting, and multi-layer perceptron. Five-fold cross-validation and model evaluation indicators [including F1 score, accuracy, precision, recall, and area under the curve (AUC)] were used to evaluate the performance of the models. The 2 best-performing models were selected for further analyze, including feature importance evaluation and Shapley additive explanations (SHAP) analysis, identifying AF recurrence risk factors, and building an AF recurrence risk prediction model.

RESULTS

The 5-year sinus rhythm maintenance rate for the patients was 82.13% (95% CI 78.51% to 85.93%). Among the 9 machine learning models, XGBoost and CatBoost models performed best, with the AUC of 0.768 (95% CI 0.742 to 0.786) and 0.762 (95% CI 0.723 to 0.801), respectively. Feature importance and SHAP analysis showed that duration of AF, preoperative left ventricular ejection fraction, postoperative heart rhythm, preoperative neutrophil-to-lymphocyte ratio, preoperative left atrial diameter, preoperative heart rate, and preoperative white blood cell were important factors for AF recurrence. Conclusion: Machine learning algorithms can be effectively used to identify potential risk factors for AF recurrence after CMP-IV. This study successfuly constructs 2 prediction model which may enhance individualized treatment plans.

Mid term freedom from atrial fibrillation following hybrid ablation, a systematic review and meta analysis

INTRODUCTION

Atrial Fibrillation (AF) is a common tachyarrhythmia affecting 33 million people worldwide. Hybrid AF ablation utilises a surgical (epicardial) ablation followed by an endocardial catheter-based ablation. The aim of this systematic review and meta-analysis is to summarize the literature reporting mid-term freedom from AF following hybrid ablation.

METHODS

An electronic search of databases was performed to identify all relevant studies providing mid-term (2 year) outcomes following hybrid ablation for AF. The primary study outcome was to assess the mid-term freedom from AF following hybrid ablation, utilising the metaprop function on Stata® (Version 17.0, StataCorp, Texas, USA). Subgroup analysis was performed to assess the impact of various operative characteristics on mid-term freedom from AF. The secondary outcomes assessed mortality and procedural complication rate.

RESULTS

The search strategy identified 16 studies qualifying for inclusion in this meta-analysis, with 1242 patients in total. The majority of papers were retrospective cohort studies (15) and one study was a randomized control trial (RCT). The mean follow up was 31.5 ± 8.4 months. Following hybrid ablation, the overall mid-term freedom from AF was 74.6% and 65.4% for patients off antiarrhythmic drugs (AAD). Actuarial freedom from AF was 78.2%, 74.2% and 73.6% at 1, 2 and 3 years respectively. No significant differences in mid-term freedom from AF based epicardial lesion set (box vs pulmonary vein isolation) or Left atrial appendage/Ganglionated Plexus/Ligament of Marshall ablation or staged vs concomitant procedures. There were 12 deaths overall following the hybrid procedure with a pooled complication rate of 5.53%.

CONCLUSION

Hybrid AF ablation offers promising mid-term freedom from AF reported at a mean follow-up of 31.5 months. The overall complication rate remains low. Further analysis of high-quality studies with randomized data and long-term follow up will help verify these results.

Elevated Serum Fibroblast Growth Factor 23 (FGF-23) Perseveres into a Convalescence Period After Elective Cardiac Surgery, with Receptor Activator of Nuclear Factor κB Ligand (RANKL) and Cartilage Oligomeric Matrix Protein (COMP) Being Part of the Peri-Surgical -Pro-Arteriosclerotic Inflammatory Response

BACKGROUND Receptor activator of nuclear factor kappa B ligand (RANKL), osteoprotegerin (OPG), cartilage oligomeric matrix protein (COMP), bone morphogenetic protein (BMP-2), and fibroblast growth factor 23 (FGF-23) are involved in inflammation, calcium deposition, and fibrosis of blood vessels. Acute changes in these factors may contribute to the progression of arteriosclerosis, especially if their elevated serum levels persist postoperatively. MATERIAL AND METHODS A total of 90 patients (79 White, 4 African American, and 7 Other) undergoing elective heart surgery were enrolled in the study. Blood was collected before surgery and after surgery at 24 hours, 7 days, and 3 months to allow for longitudinal comparisons. After the plasma isolation, several biomarkers levels were studied using an enzymatic-linked assay. Demographic and clinical information were obtained from electronic health records. RESULTS At 24 hours after surgery, RANKL (RANKLbaseline=248.7±215.7 vs RANKLt24h=376.4±329.7; P=0.035), and BMP-2 (BMP-2baseline=283.7±255.4 vs BMP-2t24h=482.4; P=0.015) were significantly elevated compared to baseline, with levels returning to baseline at 7 days. FGF-23 increased significantly from baseline (FGF-23baseline=1020±1210) to 7 days (FGF-237d=2191±5188; P=0.029) and remained significantly higher than baseline at 3 months (FGF-233m=2041±3521; P=0.044). White blood cells (WBC) remained elevated at discharge (WBCbaseline=6.8±2.1 vs WBC24h=15.0±5.3 vs WBCdischarge=8.8±3.4). IL-8 and C-reactive protein normalized at 3 months. Estimated blood loss was significantly correlated with RANKL at 24 hours (r²=0.33; P=0.035). Serum creatinine levels after surgery at 24 hours (r²=0.41; p=0.008) and 7 days (r²=0.59; P=0.000) was strongly correlated with COMP. CONCLUSIONS Persistent elevation of serum FGF-23 indicates a potential for accelerated arteriosclerosis after cardiac surgery.

Impact of pulmonary arterial systolic pressure on patients with mitral valve disease combined with atrial fibrillation

Objective

To determine whether different changes of pulmonary artery systolic pressure (PASP) after surgeries have an impact on the long-term outcomes in patients with rheumatic and degenerative mitral valve (MV) disease and atrial fibrillation.

Methods

Between 2004 and 2016, 1,188 patients with rheumatic and degenerative MV disease undergoing MV and Cox-Maze procedure were identified. Clinic outcomes, as well as rhythm state and echocardiography indices in long-term follow-up were recorded. Patients were grouped by the changes of PASP (persistently normal, persistently increased, increased, and decreased) from preoperative estimation to follow-up.

Results

A complete echocardiography was performed at baseline and after 5 years. During follow-up, free of death and atrial fibrillation (AF) off antiarrhythmic drugs was 90 and 61%, 78 and 41% at 5 and 10 years, respectively. Survival rate was higher in patients with persistently normal and became worse in patients with persistently increased and increased PASP (log-rank 166.0, P < 0.0001). Moreover, the patients with persistently normal PASP had a lowest risk of recurrent AF (SHR: 0817; CI: 0.765-0.872; P < 0.0001) after considering death as a competing risk. A persistently normal PASP at follow-up and degenerative MV disease were associated with improved survival and sinus rhythm (SR) maintenance at multivariable Cox regression analysis (P < 0.05).

Conclusion

Patients with degenerative MV disease or have persistently normal PASP during follow-up have better survival and SR maintenance rate than patients with either rheumatic MV disease or persistently abnormal PASP.

Machine learning-based analysis of risk factors for atrial fibrillation recurrence after Cox-Maze IV procedure in patients with atrial fibrillation and chronic valvular disease: A retrospective cohort study with a control group

Objectives

To evaluate the efficacy of the Cox-Maze IV procedure (CMP-IV) in combination with valve surgery in patients with both atrial fibrillation (AF) and valvular disease and use machine learning algorithms to identify potential risk factors of AF recurrence.

Methods

A total of 1,026 patients with AF and valvular disease from two hospitals were included in the study. 555 patients received the CMP-IV procedure in addition to valve surgery and left atrial appendage ligation (CMP-IV group), while 471 patients only received valve surgery and left atrial appendage ligation (Non-CMP-IV group). Kaplan-Meier analysis was used to calculate the sinus rhythm maintenance rate. 58 variables were selected as variables for each group and 10 machine learning models were developed respectively. The performance of the models was evaluated using five-fold cross-validation and metrics including F1 score, accuracy, precision, and recall. The four best-performing models for each group were selected for further analysis, including feature importance evaluation and SHAP analysis.

Results

The 5-year sinus rhythm maintenance rate in the CMP-IV group was 82.13% (95% CI: 78.51%, 85.93%), while in the Non-CMP-IV group, it was 13.40% (95% CI: 10.44%, 17.20%). The eXtreme Gradient Boosting (XGBoost), LightGBM, Category Boosting (CatBoost) and Random Fores (RF) models performed the best in the CMP-IV group, with area under the curve (AUC) values of 0.768 (95% CI: 0.742, 0.786), 0.766 (95% CI: 0.744, 0.792), 0.762 (95% CI: 0.723, 0.801), and 0.732 (95% CI: 0.701, 0.763), respectively. In the Non-CMP-IV group, the LightGBM, XGBoost, CatBoost and RF models performed the best, with AUC values of 0.738 (95% CI: 0.699, 0.777), 0.732 (95% CI: 0.694, 0.770), 0.724 (95% CI: 0.668, 0.789), and 0.716 (95% CI: 0.656, 0.774), respectively. Analysis of feature importance and SHAP revealed that duration of AF, preoperative left ventricular ejection fraction, postoperative heart rhythm, preoperative neutrophil-lymphocyte ratio, preoperative left atrial diameter and heart rate were significant factors in AF recurrence.

Conclusion

CMP-IV is effective in treating AF and multiple machine learning models were successfully developed, and several risk factors were identified for AF recurrence, which may aid clinical decision-making and optimize the individual surgical management of AF.

Superiority of complete bi-atrial ablation procedure for atrial fibrillation in rheumatic mitral valve disease

INTRODUCTION

The necessity of complete bi-atrial lesion created by radiofrequency clamp and pen for nonparoxysmal atrial fibrillation (AF) in patients with rheumatic mitral valve disease (RMVD) remains unclear.

METHODS

From January 2014 to December 2018, patients with RMVD concomitant with nonparoxysmal AF who underwent mitral valve surgery concomitant surgical ablation were retrospectively enrolled. We divided patients into Group A (complete bi-atrial lesion set created by radiofrequency clamp and pen) and Group B (simplified lesion sets created by radiofrequency clamp alone including bi-atrial ablation with incomplete mitral isthmus line and stand-alone left atrial ablation) according to the surgical ablation lesion sets. Propensity score matching was applied to analyze freedom from atrial tachyarrhythmias between the two groups.

RESULTS

Two hundred eight (38.5%) and 332 (61.5%) patients were divided into Group A and Group B, respectively. In Group B, the proportion of patients with recurrent atrial flutter in the subgroup of bi-atrial ablation with incomplete mitral isthmus line was higher than that in Group A (p = .044). After propensity score matching, there were 203 patients in each group. Better freedom from atrial tachyarrhythmias without antiarrhythmic drugs was obtained in Group A (83.1%, 79.6%, and 65.4%) than Group B (73.1%, 68.4%, and 52.7%) at 12, 36, and 60 months after operation (p = .012).

CONCLUSION

The application of radiofrequency clamp and pen to create complete bi-atrial lesion set in surgical ablation for nonparoxysmal AF in RMVD was associated with superior long-term efficacy.

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.

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.

Multicenter randomized study evaluating the outcome of ganglionated plexi ablation in maze procedure

OBJECTIVE

The benefit of adding ganglionated plexi ablation to the maze procedure remains controversial. This study aims to compare the outcomes of the maze procedure with and without ganglionated plexi ablation.

METHODS

This multicenter randomized study included 74 patients with atrial fibrillation associated with structural heart disease. Patients were randomly allocated to the ganglionated plexi ablation group (maze with ganglionated plexi ablation) or the maze group (maze without ganglionated plexi ablation). The lesion sets in the maze procedure were unified in all patients. High-frequency stimulation was applied to clearly identify and perform ganglionated plexi ablation. Patients were followed up for at least 6 months. The primary endpoint was a recurrence of atrial fibrillation.

RESULTS

The intention-to-treat analysis included 69 patients (34 in the ganglionated plexi ablation group and 35 in the maze group). No surgical mortality was observed in either group. After a mean follow-up period of 16.3 ± 7.9 months, 86.8% of patients in the ganglionated plexi ablation group and 91.4% of those in the maze group did not experience atrial fibrillation recurrence. Kaplan-Meier atrial fibrillation-free curves showed no significant difference between the two groups (P = .685). Cox proportional hazards regression analysis indicated that left atrial dimension was the only risk factor for atrial fibrillation recurrence (hazard ratio: 1.106, 95% confidence interval 1.017-1.024, P = .019).

CONCLUSION

The addition of ganglionated plexi ablation to the maze procedure does not improve early outcome when treating atrial fibrillation associated with structural heart disease.

A Modified Maze Versus Cut-and-Sew Maze for Long-Standing Persistent Atrial Fibrillation Concomitant with Mitral Valve Surgery: A Propensity Score-Matched Cohort Study

BACKGROUND

The cut-and-sew maze (CSM) procedure has an excellent efficacy for the elimination of long-standing persistent atrial fibrillation (AF) concomitant with mitral valve surgery. Because of the complexity and prolongation of cardiopulmonary bypass, CSM has not been widely used. The aim of this study was to examine a modified maze procedure that preserves the "cut-and-sew" procedure in the left atrium and uses cryoablation in the right atrium along with cavotricuspid isthmus.

METHODS

From December 2013 to December 2018, 229 patients underwent CSM, and 43 underwent the modified maze procedure during mitral valve surgery. Propensity score matching analysis was used to perform selective 1:2 ratio matching of the 43 patients undergoing the modified maze procedure with 86 patients undergoing CSM. Early operative outcomes were analyzed for differences. The absence of AF recurrence without the use of anti-arrhythmic drugs was calculated at 2 years by a generalized linear model analysis.

RESULTS

One (1.1%) early death occurred in the CSM group, and no deaths occurred in the modified maze group (p=0.722). The aortic cross-clamp durations were 76.30±8.86 minutes for the modified maze and 92.38±10.88 for the CSM procedure (p<0.001). There were no late strokes or deaths during the 2-year follow-up. The modified maze group showed similar rates of absence of AF without the use of anti-arrhythmic drugs as the CSM group within the 2 years (p=0.332).

CONCLUSION

This modified maze simplifies the "cut-and-sew" procedure and reduces operating time while retaining the efficacy of CSM.

Rare case of papillary fibroelastoma resection with concomitant cox-maze IV procedure

Primary cardiac tumors represent 0.1% of all cardiac tumors, making them a rare pathologic phenomenon. The second most common cardiac tumors are papillary fibroelastomas, which also represent the most common valvular tumors. This report examines a rare case of a patient that underwent resection of papillary fibroelastoma with simultaneous Cox-Maze IV procedure for treatment of atrial fibrillation. This 67-year-old male patient was initially scheduled for transcatheter ablation for treatment of rate-controlled atrial fibrillation. During a pre-procedural trans-thoracic echocardiogram, it was discovered that the patient had a moderately sized pedunculated mass on the aortic valve, suspicious of papillary fibroelastoma. Despite the patient having no history of embolic events or aortic insufficiency from the papillary fibroelastoma, the transcatheter ablation procedure was canceled. He was referred to cardiothoracic surgery for further evaluation, and it was determined that this patient was a candidate for papillary fibroelastoma resection along with Cox-Maze IV procedure for atrial fibrillation.

Mid‐term outcomes of concomitant Cox‐Maze IV: Results from a multicenter prospective registry

Background

Benefits of concomitant atrial fibrillation (AF) surgical treatment are well established. Cardiac societies support treating AF during cardiac surgery with a class I recommendation. Despite these guidelines, adoption has been inconsistent. We report results of routine performance of concomitant Cox‐Maze IV (CMIV) from participating centers using a standardized, prospective registry.

Methods

Nine surgeons at four cardiac surgery programs enrolled 807 patients undergoing concomitant CMIV surgery over 12 years. Lesions were created using bipolar radiofrequency clamps and cryoablation probes. Follow‐up occurred at 3‐ and 6‐months, then annually for 3 years. Freedom from AF was defined as no episode >30 s of atrial arrhythmia.

Results

Sixty‐four percent of patients were male, mean age 69 years, mean left atrial size 4.6 cm, mean preoperative AF duration 4.0 years, mean EuroSCORE 6.4, and mean CHADS₂ score 3.1. Thirty‐day postoperative mortality and neurologic event rates were 3.3% and 1.3%, respectively. New pacemaker implant rate was 6.3%. Freedom from AF rates at 1‐ and 3‐years stratified by preoperative AF type were: paroxysmal 94.6% and 87.5%, persistent 82.1% and 81.9%, and longstanding persistent 84.1% and 78.1%. At 3‐year follow up, 84% of patients were off antiarrhythmic drugs and 74% of sinus rhythm patients were off oral anticoagulants.

Conclusions

Routine CMIV is safe and effective. Acceptable outcomes can be achieved across multiple centers and multiple operators even in a moderate risk patient population undergoing more complex procedures. Surgeons and institutions should be encouraged by all cardiac societies to adopt the CMIV procedure to maximize patient benefit.

Effect of electrophysiological mapping on non-transmural annulus ablation and atrial fibrillation recurrence prediction after 6 months of Cox-Maze IV procedure

OBJECTIVE

The objective of this study was to observe the safety and efficacy of electrophysiological mapping following the Cox-Maze IV procedure and to investigate whether a correlation exists between recurrence of atrial fibrillation (AF) with the completeness of bidirectional electrical isolation and the inducibility of AF immediately after the Cox-Maze IV procedure.

METHODS

Totally, 80 consecutive patients who suffered from aortic valve or mitral valve disease and persistent AF were randomly enrolled into the control group and electrophysiological mapping following the Cox-Maze IV group (Electrophysio-Maze group). In the Electrophysio-Maze group, patients underwent concomitant Cox-Maze procedure and following electrophysiological mapping of ablation lines in mitral isthmus, left atrial "box," and tricuspid annulus. If the bidirectional electrical isolation of tricuspid annulus ablation line is incomplete, whether to implement supplementary ablation will be independently decided by the operator. Before and after the Cox-Maze IV procedure, AF induction was performed. All patients in both groups were continuously followed-up and underwent electrocardiogram Holter monitoring after 6 months.

RESULTS

In total, 42 Electrophysio-Maze patients and 38 controls were enrolled. Compared with patients in the control group, there were shorter hospital stay, better cardiac remodeling changes, and higher relief from AF during the follow-up period of 6 months in the Electrophysio-Maze group. Within the Electrophysio-Maze group, the rate of incomplete the bidirectional electrical isolation of "box" ablation lines was zero, and the rate of incomplete bidirectional electrical isolation of mitral isthmus ablation line or tricuspid annulus ablation line was 23.8%. After two cases of successful complementary ablation on the tricuspid annulus ablation line, the final incomplete bidirectional electrical isolation of annulus ablation lines was 19.0%. There were correlations between late AF recurrence after 6 months with incomplete bidirectional electrical isolation of annulus ablation lines and AF induction immediately after the Cox-Maze IV procedure.

CONCLUSION

Electrophysiological mapping following the Cox-Maze procedure is safe and effective. Electrophysiological mapping in the Cox-Maze procedure can find out the non-transmural annulus ablation lines by assessing the completeness of bidirectional electrical isolation of ablation lines, guide supplementary ablation, and predict AF recurrence after 6 months.

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.

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.

Atrial fibrillation management during septal myectomy for hypertrophic cardiomyopathy: A systematic review

INTRODUCTION

Atrial fibrillation is common in patients with hypertrophic cardiomyopathy, and significantly impacts mortality and morbidity. In patients with atrial fibrillation undergoing septal myectomy, concomitant surgery for atrial fibrillation may improve outcomes.

METHODS

A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All studies reporting the outcomes of combined septal myectomy and atrial fibrillation surgery were included.

RESULTS

A total of 10 observational studies were identified, including 644 patients. Most patients had paroxysmal atrial fibrillation. The proportion with prior unsuccessful ablation ranged from 0 to 19%, and preoperative left atrial diameter ranged from 44 ± 17 to 52 ± 8 mm. Cox-Maze IV (n = 311) was the most common technique used, followed by pulmonary vein isolation (n = 222) and Cox-Maze III (n = 98). Patients with persistent or longstanding atrial fibrillation more frequently received Cox-Maze III/IV. Ranges of early postoperative outcomes included: mortality 0 to 7%, recurrence of atrial tachyarrhythmias 4.4 to 48%, cerebrovascular events 0 to 1.5%, and pacemaker insertion 3 to 21%. Long-term data was limited. Freedom from atrial tachyarrhythmias at 1 year ranged from 74% to 96%, and at 5 years from 52% to 100%. Preoperative predictors of late atrial tachyarrhythmia recurrence included left atrial diameter >45 mm, persistent or longstanding preoperative atrial fibrillation and longer atrial fibrillation duration.

CONCLUSION

In patients with atrial fibrillation undergoing septal myectomy, the addition of ablation surgery adds low overall risk to the procedure, and likely reduces the risk of recurrent atrial fibrillation in the long term. Future randomised studies comparing septal myectomy with or without concomitant AF ablation are needed.

Clinical Efficacy and Safety of Cox-Maze IV Procedure for Atrial Fibrillation in Patients With Hypertrophic Obstructive Cardiomyopathy

Objective: Atrial fibrillation is the most prevalent persistent arrhythmia in patients with hypertrophic obstructive cardiomyopathy. Comparative analyses of the safety and effectiveness of septal myectomy with and without surgical ablation are limited. This study aimed to compare the outcomes of septal myectomy with and without the Cox-maze IV procedure in patients with hypertrophic obstructive cardiomyopathy and atrial fibrillation. Methods: Ninety-four patients with hypertrophic obstructive cardiomyopathy and atrial fibrillation who underwent septal myectomy were analyzed, we divided it into concomitant Cox maze surgery (Cox-maze group) and no concomitant Cox maze operation (no Cox-maze group). Freedom from atrial fibrillation recurrence and all-cause mortality after surgery were assessed. Results: Freedom from all-cause mortality after septal myectomy at 1, 3, and 5 years was 98.5 ± 1.5% each in the Cox-maze group and 90.8 ± 6.3%, 85.1 ± 8.1%, and 85.1 ± 8.1%, respectively, in the no Cox-maze group. Patients in the no Cox-maze group had lower survival, freedom from atrial fibrillation recurrence off antiarrhythmic drugs, and arrhythmia control rate (including patients with successful antiarrhythmic drug conversion) than those in the Cox-maze group (P = 0.046, P = 0.040, and P = 0.012, respectively). Patients who underwent the Cox-maze IV procedure had lower atrial fibrillation recurrence rate than those who did not (hazard ratio, 0.141; 95% confidence interval, 0.042-0.479; P = 0.002). Post-operative increases in left atrial diameters (hazard ratio, 1.099; 95% confidence interval, 1.024-1.179; P = 0.009) were associated with atrial fibrillation recurrence. Conclusions: The Cox-maze IV procedure combined with septal myectomy improved mid-term survival and reduced mid-term atrial fibrillation recurrence in patients with hypertrophic obstructive cardiomyopathy and atrial fibrillation. The concomitant Cox-maze IV procedure was associated with a lower atrial fibrillation recurrence in patients with surgical hypertrophic obstructive cardiomyopathy and atrial fibrillation.

Bi-atrial or left atrial ablation of atrial fibrillation during concomitant cardiac surgery: A Bayesian network meta-analysis of randomized controlled trials

OBJECTIVE

Surgical ablation of atrial fibrillation (AF) has become a routine procedure during concomitant cardiac surgery, however, the extension of lesion sets remain controversial. We sought to compare the relative benefit and risk of different lesion sets through a Bayesian network meta-analysis (NMA).

METHODS

Pubmed, Embase, and Cochrane Trials databases were searched for randomized controlled trials (RCTs) comparing the rhythm outcome of AF patients undergoing pulmonary vein isolation (PVI), left atrial Maze (LAM), bi-atrial Maze (BAM), or no ablation during concomitant cardiac surgery. An NMA was conducted to explore the difference of over 1 year AF freedom as well as risks for early mortality and permanent pacemaker implantation (PPMI).

RESULTS

A total of 2031 patients of 19 RCTs were included. PVI, LAM, and BAM (OR [95% Cr.I]: 5.02 [2.72, 10.02], 7.97 [4.93, 14.29], 8.29 [4.90, 14.86], p < .05) demonstrated higher freedom of AF compared with no ablation, however, no significant difference of rhythm outcome was found among the three ablation strategies based on the random-effects model. BAM was associated with an increase in early mortality when compared with no ablation (OR [95% Cr.I]: 4.08 [1.23, 17.30], p < .05), while none of the remaining comparisons reached statistical difference in terms of early mortality and PPMI.

CONCLUSION

Bi-atrial ablation is not superior to left atrial ablation strategies in reducing AF recurrence for un-selected surgical patients. BAM has a higher risk of early mortality than no ablation, but no difference was found between bi-atrial and left atrial ablation in regard to early mortality and PPMI based on the current evidence.

The Role of Exosomes and Their Cargos in the Mechanism, Diagnosis, and Treatment of Atrial Fibrillation

Atrial fibrillation (AF) is the most common persistent arrhythmia, but the mechanism of AF has not been fully elucidated, and existing approaches to diagnosis and treatment face limitations. Recently, exosomes have attracted considerable interest in AF research due to their high stability, specificity and cell-targeting ability. The aim of this review is to summarize recent literature, analyze the advantages and limitations of exosomes, and to provide new ideas for their use in understanding the mechanism and improving the diagnosis and treatment of AF.

Epicardial course of the musculature related to the great cardiac vein: Anatomical considerations and clinical implications for mitral isthmus block after vein of Marshall ethanol infusion

BACKGROUND

Mitral isthmus gaps have been ascribed to an epicardial musculature anatomically related to the great cardiac vein (GCV) and the vein of Marshall (VOM). Their lumen offers an access for radiofrequency application or ethanol infusion, respectively.

OBJECTIVE

The purpose of this study was to evaluate the frequency of mitral isthmus gaps accessible via the GCV lumen, to assess their location around the GCV circumference, and to propose an efficient ablation strategy when present.

METHODS

One hundred consecutive patients underwent VOM ethanol infusion (step 1) and endocardial linear ablation from the mitral annulus to the left inferior pulmonary vein (step 2). In cases of mitral isthmus gap, endovascular ablation of the GCV anchored wall facing the left atrium was systematically performed (step 3), while the opposite GCV free wall was targeted in case of block failure only (step 4).

RESULTS

After VOM ethanol infusion and endocardial ablation, mitral isthmus block occurred in 51 patients (51%). Pacing maneuvers and activation sequences demonstrated an epicardial gap via the VOM in 2 patients (2%) and via the GCV in 47 patients (47%). In the latter case, block was achieved at the GCV anchored wall in 42 patients (89%) and the GCV free wall in 5 patients (11%). Global success rate of mitral isthmus block was 98%. No tamponade occurred.

CONCLUSION

With the advent of VOM ethanol infusion, residual mitral isthmus gaps are mostly eliminated within the first centimeter of the GCV. Thorough mapping of the entire circumference of the GCV wall can help identify these epicardial gaps.

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.

Cryosurgery for Atrial Fibrillation: Physiologic Basis for Creating Optimal Cryolesions

BACKGROUND

Although cryosurgery has been used to treat cardiac arrhythmias for nearly 5 decades, the mechanism of action and the surgical technique that produces optimal cryolesions for the treatment of atrial fibrillation are still poorly understood. This has resulted in surgical outcomes that can be improved by a better understanding the mechanisms of cryothermia ablation and the proper surgical techniques that take advantage of those mechanisms.

METHODS

The cryobiology underlying cryosurgical ablation is described, as are the nuances of cryosurgical techniques that ensure the reliable creation of contiguous, uniformly transmural atrial cryolesions. The oft-misunderstood "2-minute rule" for the application of cryothermia is clarified in detail, along with its variations that depend on target myocardial temperature.

RESULTS

The creation of optimal cryolesions depends on cryoprobe temperature, the temperature of the target myocardium, the duration of cryothermia application, and the presence or absence of a "heat sink" or "cooling sink" created by intracavitary blood circulation. Cryothermia kills myocardial cells during both the freezing and thawing phases of cryoablation cycle. The critical lethal temperature for myocardium is -30°C. The slower the target tissue thaws, the higher the percentage of cell death.

CONCLUSIONS

The availability of cryosurgical techniques has revolutionized the surgical treatment of atrial fibrillation. By utilizing modern cryosurgical devices and adhering to the technical principles described, surgeons can now perform surgical procedures for atrial fibrillation that are quicker, safer, and as effective as the standard Maze-III/IV procedure.

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.

Preoperative Noninvasive Mapping Allowed Targeted Concomitant Surgical Ablation and Revealed COVID-19 Infection

In March 2020, a 64-year-old female with mitral valve insufficiency and persistent atrial fibrillation underwent preoperative noninvasive mapping for developing an ablation strategy. In the computed tomography (CT) scan, typical signs of COVID-19 were described. Since the consecutive polymerase chain reaction (PCR) test was negative, the severely symptomatic patient was planned for urgent surgery. Noninvasive mapping showed that atrial fibrillation was maintained by left atrial structures and pulmonary veins only. On admission day, the preoperative routine COVID-19 PCR test was positive, and after recovery, uneventful mitral valve repair with cryoablation of the left atrium and pulmonary veins was performed. Our case describes the potential benefit of preoperative noninvasive mapping for the development of a surgical ablation strategy, as well as the challenges in managing urgent surgical patients during the COVID-19 pandemic and the corresponding diagnostic relevance of CT.

Insights from advancements and pathbreaking research on the minimally invasive treatment of atrial fibrillation

Atrial fibrillation (AF) remains the most common cardiac arrhythmia with increasing prevalence in developed and aging countries. Pharmacological antiarrhythmic therapy has low effectiveness and is limited by its toxicity. Developed in 1987 by James Cox surgical ablation of AF called MAZE procedure was very effective, but due to its invasiveness and complexity was not widely adopted. Landmark research done by Haissaguerre in 1998 initiated a new approach for treatment namely percutaneous catheter ablation, which remains a class I/A indication in symptomatic paroxysmal AF refractory to optimal medical therapy. However, its efficacy in patients with persistent atrial fibrillation (PSAF) is far from satisfactory. Recent advancements in devices and techniques of minimally invasive surgical ablation show very good results in the treatment of PSAF. Current guidelines equate surgical with catheter ablation within the scope of efficacy indicating that both may be considered as an effective and safe treatment option for patients with persistent forms of arrhythmia. The higher efficacy of surgical ablation was confirmed at a 7-year follow-up of FAST trial with recurrence rate as high as 87% in catheter arm compared with 56% in thoracoscopic ablation arm. A new concept of the invasive treatment of AF consisting of combined surgical (epicardial) and electrophysiological (endocardial) was introduced in 2009. Recently experts' opinions and published data suggest that the proper hybrid treatment consisting of a planned combination of surgical and catheter ablation may give even better results. One of the most invaluable benefits of surgical ablations is the possibility of concomitant occlusion of the left atrial appendage. Recently good results have been reported for the novel epicardial clip for closing the left atrial appendage, which is placed in the deployment loop on a disposable holder.

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.