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Background: Atrial tachycardias (ATs) frequently develop after a surgical Maze procedure. We aimed to elucidate the electrophysiologic mechanisms and their arrhythmogenic substrates of these ATs., Methods and Results: We retrospectively reviewed 20 patients (14 females, mean age of 55.5 ± 8.6 years) with post-Maze ATs who underwent high-resolution mapping at three institutions. The slow conduction areas, reentry circuits, voltage signals, complex electrograms, and their correlation with the surgical incisions and lesions placed in the surgical Maze procedures were analyzed. Thirty-six ATs with a mean cycle length of 260.0 ± 67.6 ms were mapped in these patients. Among them, 22 (61.1%) were anatomical macro-reentrant ATs (AMAT), 12 (33.3%) non-AMATs (localized ATs), and 2 (5.6%) focal ATs, respectively. Epicardial conduction bridges were observed in 6/20 (30.0%) patients and 7/36 (19.4%) ATs. Different arrhythmogenic substrates were identified in these ATs, including slow conduction regions within the previous lesion areas or between the incisions and anatomical structures, the prolonged activation pathways caused by the short lesions connecting the tricuspid annulus, and the circuits around the long incisions and/or lesions., Conclusions: Reentry is the main mechanism of the post-Maze ATs. The pro-arrhythmic substrates are most likely caused by surgical incisions and lesions. The slow conduction regions and the protected channels yielded from these areas are the major arrhythmogenic factors., Competing Interests: Conflict of interest: M.C. and L.Z. report receiving lecture fees from Boston Scientific. All remaining authors have declared no conflicts of interest., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Society of Cardiology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

A significant proportion of patients undergoing repair of congenital mitral valve disease will require a subsequent reoperation. During somatic growth, mitral valve repair is preferable to replacement as it allows for annular growth, preservation of ventricular function, and avoidance of lifelong anticoagulation. Techniques to facilitate successful re-repairs for congenital and non-rheumatic mixed degenerative mitral valve disease are not well-described in the literature. Description of the encountered pathology and surgical maneuvers utilized in this case provides real-world tools to help surgeons deal with limited orifice availability, fibrosis, and multilevel lesions. We describe a mitral valve re-repair in a young athlete for a rare cleft posterior mitral leaflet, with a simultaneous tricuspid valve repair and Cox-Maze procedure. We focus on technical pearls that address specific anatomic challenges within our surgical approach.

Background Facing longer follow-up of patients after Fontan operation, Fontan conversion was proposed to treat failing Fontan circulation. We reviewed our patients who reached up to 42 years of age. Methods Fifteen consecutive patients underwent Fontan conversion to extracardiac conduit combined with biatrial maze procedure between October 2006 and January 2014.Mean age at conversion was 30.9 ± 5.6 years and mean interval from primary Fontan palliation to conversion was 23.2 ± 3.3 years. Results There was one early death. Ten of 14 survivors were extubated within 24 hours, and 11 were discharged from intensive care unit (ICU) within 7 days. The impaired left ventricular function, presented in four patients prior to surgery, improved from EF 43.8 to 54.8% (p = 0.02). During follow-up time of 3.6 ± 2.3 years after conversion, there was no late death and no reoperation. Two patients developed recurrent atrial arrhythmia. Older age at Fontan procedure, lower left ventricular function, higher New York Heart Association (NYHA) class, and anatomy other than tricuspid atresia emerged as risk factors for longer ICU stay. Conclusion Fontan conversion improved the functional status in almost all patients. A concomitant maze procedure effectively eliminated atrial arrhythmia. This procedure provides a benefit even for older patients if all additional cardiac pathologies are addressed. [ABSTRACT FROM AUTHOR]

Background Limited data exist regarding the outcome of atrial fibrillation (AF) surgery and catheter ablation in patients with hypertrophic cardiomyopathy (HCM). Objective The purpose of this study was to evaluate the safety and efficacy of nonpharmacologic treatment of AF in HCM. Methods One hundred forty-seven patients (46 female, age 55 ± 11 years, ejection fraction [EF] 58% ± 8%) with symptomatic paroxysmal (58%), persistent (31%), and long-standing persistent AF (11%) refractory to antiarrhythmic drugs who presented for their first catheter ablation (n = 79) or AF surgery (n = 68) were included. Results After follow-up of 35 months (interquartile range 13, 60), 29% of patients who underwent catheter ablation and 51% of those who had undergone AF surgery had no documented recurrent atrial arrhythmia after a single procedure. Repeat ablation was performed in 55% of patients with recurrent arrhythmia in the catheter group and 24% in the surgery group, increasing the success rate to 39% and 53%, respectively, after 1 or more procedures. Predictors of success after the first procedure in a multivariable setting included higher baseline EF and male gender. Persistent or long-standing AF and log of AF duration were associated with lower success. Major complications occurred in 6% of the catheter ablation group and 18% of the AF surgery group. During follow-up, 16 patients died (9 in catheter group, 7 in surgery group) and 1 underwent heart replacement. Lower baseline EF and older age were independently associated with death. Conclusion Catheter ablation and AF surgery are associated with symptomatic improvement in HCM patients. However, long-term success is lower and complications are higher than previously reported. [ABSTRACT FROM AUTHOR]

The Cox-maze procedure for the restoration of normal sinus rhythm, initially developed by Dr. James Cox, underwent several iterations over the years. The main concept consists of creating a series of transmural lesions in the right and left atria that disrupt re-entrant circuits responsible for propagating the abnormal atrial fibrillation rhythm. The left atrial appendage is excluded as a component of the Maze procedure. For the first three iterations of the Cox- maze procedure, these lesions were performed using a surgical cut-and-sew approach that ensured transmurality. The Cox-Maze IV is the most currently accepted iteration. It achieves the same lesion set of the Cox- maze III but uses alternative energy sources to create the transmural lesions, potentially in a minimally invasive approach on the beating heart. High-frequency ultrasound, microwave, and laser energy have all been used with varying success in the past. Today, bipolar radiofrequency heat or cryotherapy cooling are the most accepted sources for creating linear lesions with consistent safety and transmurality. The robust and reliable nature of these energy delivery methods has yielded a success rate reaching 90% freedom from atrial fibrillation at 12 months. Such approaches offer a significant long-term advantage over catheter-based ablation, especially in patients having longstanding, persistent atrial fibrillation with characteristics such as dilated left atrial dimensions, poor ejection fraction, and failed catheter ablation. Based on these improved results, there currently is significant interest in developing a hybrid ablation strategy that incorporates the superior transmural robust lesions of surgical ablation, the reliable stroke prevention potential of epicardial left atrial appendage exclusion, and sophisticated mapping and confirmatory catheter-based ablation technology. Such a minimally invasive hybrid strategy for ablation may lead to the development of multidisciplinary "Afib teams" to obtain optimal long-term sinus rhythm control. This article provides an overview of current surgical strategies for patients with atrial fibrillation and addresses the two main goals in its management. [ABSTRACT FROM AUTHOR]

Background: It is unknown whether early atrial tachyarrhythmia (ATA) recurrence occurring within 3 months after the Maze procedure predicts late ATA recurrence., Methods and results: This study involved 610 patients who underwent the modified Cryo-Maze procedure in conjunction with other cardiac surgery. The primary outcomes were late ATA recurrence, defined as occurring ≥3 months after surgery. The effects of early ATA recurrence on late ATA recurrence were analyzed using a Cox proportional hazards model. The following 11 covariates were considered explanatory variables: early ATA recurrence, age, sex, body surface area, preoperative duration of atrial fibrillation, preoperative left atrial diameter, and concomitant surgery (mitral valve replacement, mitral valve repair, aortic valve replacement, tricuspid annuloplasty, and left atrial appendage closure). Statistical analyses were performed with a 2-sided 5% significance level. Early ATA recurrence occurred in 174 patients (28.5%). Late ATA recurrence occurred in 167 patients (27.5%), with 595 events identified in these patients. The Cox proportional hazards model showed that early ATA recurrence was an independent predictor of late ATA recurrence (hazard ratio, 4.14; 95% confidence interval, 3.00-5.70; P<0.001)., Conclusions: Early ATA recurrence was an independent predictor of late ATA recurrence among patients undergoing the modified Cryo-Maze procedure. The blanking period might not be applied to patients undergoing the modified Cryo-Maze procedure.

Background: Cryoablation is effective for not only ablating the myocardium, but also maintaining the structure of the ablated tissue. However, data comparing nitrous oxide (N 2 O)-based and argon gas-based cryoprobes are limited., Methods: This study was a follow-up study of a single-center, prospective, randomized controlled trial in which 60 patients were randomly allocated to either the N 2 O group or the argon group. The primary endpoint of this study was sinus rhythm maintenance, and the key secondary endpoint was a composite of major adverse cardiovascular and cerebrovascular events (MACCEs) (ie, cardiac death, stroke, major bleeding, and readmission for heart failure)., Results: The baseline and operative characteristics of the patients in the N 2 O and argon groups were comparable. At the 5-year follow-up, the rate of sinus rhythm maintenance was 81.8% in the N 2 O group, whereas it was 78.5% in the argon group (P > .999). No significant differences in the rate of freedom from MACCEs (80.6% in the N 2 O group vs 81.9% in the argon group; P = .978) were observed at the 5-year follow-up. The left atrial volume index decreased over time from 114.65 mL/m 2 to 65.74 mL/m 2 (P < .0001) and reached similar values in the 2 groups (P = .279) at the 5-year follow-up., Conclusions: Both N 2 O- and argon gas-based cryoprobes showed similar rates of sinus rhythm maintenance and freedom from MACCEs at the 5-year follow-up. Both cryoprobes might have similar efficacy and safety in the arrested heart in the long term., (Copyright © 2022 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

OBJECTIVES The aim of the study was to investigate the efficacy and safety of the Dallas lesion set, which mimics the Cox-maze III left atrial (LA) lesions, for long-standing persistent atrial fibrillation (LSPAF). METHODS Over a 4-year period, 103 LSPAF patients were treated with the Dallas lesion set. Linear lesions were created at the roofline, at the anterior line and between the roofline and left atrial appendage (LAA). All patients underwent ganglionated plexi ablation and LAA excision as well as pulmonary vein isolation. Follow-up at 6, 12 and 24 months was performed by 48-h Holter recordings and real-time 3-dimensional echocardiography. RESULTS At the 24-month follow-up, 83 of 103 (80.6%) patients were free of any atrial arrhythmia lasting >30 s, with 77 patients (74.8%) off of antiarrhythmic drugs (AADs). At 3.1 ± 0.7 years, 74 of 103 patients (71.8%) were in sinus rhythm, with 71 patients (68.9%) off AADs. The optimal cut-off value of LA dimension to discriminate atrial arrhythmia recurrence was 55 mm (receiver operating characteristic curve analysis), and the Kaplan–Meier analysis showed that patients with an LA dimension of <55 mm had less recurrence during the follow-up (log-rank test, P = 0.015). After 6 months, a significant reduction in LA volume and improvement in LA function was noted in patients without recurrence (P < 0.05). In contrast, patients with recurrence showed no improvement in LA volume or function. CONCLUSIONS The Dallas lesion set is an effective treatment in patients with LSPAF. It resulted in significant improvement in LA volume and function after restoration of sinus rhythm. [ABSTRACT FROM AUTHOR]

Objective: Radiofrequency ablation (RFA) makes the Cox-Maze procedure less complicated but cannot always achieve transmural lesions. In this study, we assessed whether repeated application of RFA could improve histological transmurality even in thick lesions. Methods: Left atrial appendages (LAA) amputated from 20 consecutive patients (age 68 ± 9 years, 9 males) who underwent the Cox-Maze procedure using bipolar RFA devices were studied. Three different segments in the amputated LAA were ablated once, twice, or three times. Thereafter, cross sections made along each of the ablation lines were histologically assessed. Transmurality, which was defined as completion of transmural fibrotic changes, and wall thickness were investigated at an average of 3 different sites in each section. Results: A total of 177 sites were investigated and divided into groups with single, double, and triple RFA treatments for 56, 61, and 60 lesions, respectively. Transmural lesions were observed in 25 (45 %), 27 (44 %), and 41 (68 %) lesions, respectively ( P = 0.011). The transmurality was 100 % for all lesions with a thickness of 1.0 mm or less. In the thicker lesions (>1.0 mm), however, wall thickness impaired transmurality, though triple RFA was associated with significantly higher transmurality than single and double RFA ( P = 0.005). Conclusions: Triple repetition of RFA was associated with higher transmurality of lesions than double RFA, especially for thicker lesions. Increasing the number of repetitions could improve the success rate of the Cox-Maze procedure using RFA devices. [ABSTRACT FROM AUTHOR]

Objective To compare the therapeutic effects and safety of monopolar and bipolar radiofrequency (RF) ablation used during cardiac surgery to treat atrial fibrillation. Methods We retrospectively studied a total of 81 patients with chronic atrial fibrillation who underwent open cardiac surgery with concomitant RF ablation between January 2007 and March 2011. Fifty-eight patients received bipolar RF ablation and 23 received monopolar RF ablation, respectively. The sinus rhythm restoration rate, the procedural duration, the frequency of severe perioperative complications, and mortality were compared between the two groups. Results The sinus rhythm restoration rate did not differ significantly between the two groups after follow-up of 15.1 ± 12.6 months ( P =0.199). The frequencies of severe perioperative complications and mortality were also similar in the two groups. The total procedural time using bipolar RF ablation was significantly shorter than that using monopolar ablation (19.7±4.6 minutes vs . 28.1±8.5 minutes, P < 0.001). Conclusions Both monopolar and bipolar RF ablation are safe and effective in treating chronic atrial fibrillation patients during open cardiac surgery, but bipolar RF ablation is more convenient in practice. [ABSTRACT FROM AUTHOR]

Background: Ablation technology has been introduced to replace the surgical incisions of the Cox-Maze procedure in order to simplify the operation. However, the efficacy of these ablation devices has not been prospectively evaluated. Objective: The purpose of this study was to examine the efficacy and safety of irrigated unipolar and bipolar radiofrequency ablation for the treatment of persistent and long-standing persistent atrial fibrillation (AF) during concomitant cardiac surgical procedures. Methods: Between May 2007 and July 2011, 150 consecutive patients were enrolled at 15 U.S. centers. Patients were followed for 6 to 9 months, at which time a 24-hour Holter recording and echocardiogram were obtained. Recurrent AF was defined as any atrial tachyarrhythmia (ATA) lasting over 30 seconds on the Holter monitor. The safety end-point was the percent of patients who suffered a major adverse event within 30 days of surgery. All patients underwent a biatrial Cox-Maze lesion set. Results: Operative mortality was 4%, and there were 4 (3%) 30-day major adverse events. Overall freedom from ATAs was 66%, with 53% of patients free from ATAs and also off antiarrhythmic drugs at 6 to 9 months. Increased left atrial diameter, shorter total ablation time, and an increasing number of concomitant procedures were associated with recurrent AF (P <.05). Conclusion: Irrigated radiofrequency ablation for treatment of AF during cardiac surgery was associated with a low complication rate. No device-related complications occurred. The Cox-Maze lesion set was effective at restoring sinus rhythm and had higher success rates in patients with smaller left atrial diameters and longer ablation times. [Copyright &y& Elsevier]

OBJECTIVES We previously reported favourable short-term results of our ‘trans-septal maze procedure’, a novel technique for creating biatrial lesions through a septal-superior approach during mitral valve surgery. Here, we reviewed the mid-term results of this procedure and determined the impact of restored left atrial (LA) contraction on late outcomes. METHODS We examined clinical data of 50 patients with persistent (n = 7) or long-standing persistent atrial fibrillation (AF) (n = 43) (mean period of rhythm disturbance 77 ± 78 months) who underwent a trans-septal maze procedure concomitant with mitral valve surgery and were followed postoperatively for at least 24 months. The mean preoperative LA dimension was 59 ± 9 mm (40–85 mm). The presence of an A wave in Doppler echocardiography was considered to indicate evidence of LA mechanical contraction. Serial echocardiography was performed to evaluate left ventricular and LA dimensions, degree of valvular regurgitation and estimated systolic pulmonary artery (PA) pressure. Follow-up was completed with a mean duration of 59 ± 17 months (27–92 months). RESULTS There were no ablation-related complications and 48 patients (96%) were free from AF immediately after the operation. At the latest follow-up, 39 patients (78%) were free from AF, while 28 (56%) presented LA mechanical contraction. Patients who restored LA mechanical contraction were less likely to experience postoperative thromboembolic events (4 vs 23%, P = 0.075), as compared with those who did not restore it. Serial echocardiography showed that patients with restored LA contraction showed improvement in Doppler-derived systolic PA pressure to a greater degree and less incidence of significant tricuspid regurgitation (7 vs 41%, P = 0.006). The Cox proportional hazards models with adjustments for all other covariates revealed LA dimension >60 mm at baseline as an independent risk factor for lack of LA mechanical contraction (adjusted hazards ratio 3.9, 95% confidence interval 1.1–14, P = 0.035). CONCLUSIONS Our trans-septal maze procedure may be an effective alternative surgical treatment for eliminating AF during mitral valve surgery. In patients with valvular AF, early surgery is warranted to restore sinus rhythm with LA mechanical contraction, before severe LA dilatation occurs. The impact of LA contraction recovery conferred by AF ablation on postoperative haemodynamic improvements and thromboembolic events remains to be determined. [ABSTRACT FROM AUTHOR]

There is no solid evidence from the literature that compare Cox-Maze with pulmonary vein isolation techniques for atrial fibrillation in the context of concomitant mitral valve surgery. Although the first is perhaps more effective and linked to higher freedom from atrial fibrillation, it is more invasive compared to the pulmonary isolation., (© 2022 Wiley Periodicals LLC.)

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., (© 2022 The Authors. Journal of Cardiac Surgery published by Wiley Periodicals LLC.)

Background: Atrial fibrillation (Afib) is a marker of increased cardiovascular morbidity and mortality. Owing to the increased prevalence of Afib in patients undergoing cardiac surgery, assessing the effect of Afib on postsurgical outcomes is important. We aimed to analyze the effect of preoperative Afib on clinical outcomes in patients undergoing cardiac surgery using a large surgical database., Methods: This retrospective cohort study was based on the national health claims database established by the National Health Insurance Service of the Republic of Korea from 2009 to 2015. Diagnosis and procedure codes were used to identify diseases according to the International Statistical Classification of Diseases, 10th revision., Results: We included 1,037 patients (0.1%) who had undergone cardiac surgery from a randomized 1,000,000-patient cohort, and 15 patients (1.5%) treated with isolated surgical Afib ablation were excluded. Of these 1,022 patients, 412 (39.7%), 303 (29.2%), and 92 (9.0%) underwent coronary artery bypass, heart valve surgery, and Cox-maze surgery, respectively. Preoperative Afib was associated with higher patient mortality (p=0.028), regardless of the surgical procedure. Patients with preoperative Afib (n=190, 18.6%) experienced a higher cumulative risk of overall mortality (hazard ratio [HR], 1.435; 95% confidence interval [CI], 1.263-2.107; p=0.034). Subgroup analysis revealed a reduced risk of overall mortality with Cox-maze surgery in Afib patients (HR, 0.500; 95% CI, 0.266-0.938; p=0.031). Postoperative cerebral ischemia or hemorrhage events were not related to Afib., Conclusion: Preoperative Afib was independently associated with worse long-term postoperative outcomes after cardiac surgery. Concomitant Cox-maze surgery may improve the survival rate.

An anatomical understanding of the atrial myocardium is crucial for surgeons and interventionists who treat atrial arrhythmias. We reviewed the anatomy of the inter-nodal and intra-atrial conduction systems. The anterior inter-nodal route (#1) arises from the sinus node and runs through the ventral wall of the atrial chambers. The major branch of route #1 approaches the atrioventricular node from the anterior aspect. Other branches of route #1 are Bachmann's bundle and a vestibular branch around the tricuspid valve. The middle inter-nodal route (#2) begins with a broad span of fibers at the sinus venarum and extends to the superior limbus of the oval fossa. The major branch of route #2 joins with the branch of route #1 at the anterior part of the atrioventricular node. The posterior inter-nodal route (#3) is at the terminal crest and gives rise to many branches at the pectinate muscles of the right atrium and then approaches the posterior atrioventricular node after joining with the vestibular branch of route #1. The branches of the left part of Bachmann's bundle and the branches of the second inter-nodal route form a thin myocardial network at the posterior wall of the left atrium. These anatomical structures could be categorized into major routes and side branches. There are 9 or more anatomical circles in the atrial chambers that could be structural sites for macro re-entry. The implications of normal and abnormal structures of the myocardium for the pathogenesis and treatment of atrial arrhythmias are discussed.

Objectives: The goal of the present study was to determine the safety and efficacy of a modified off-pump biatrial mini-maze procedure to treat long-standing persistent atrial fibrillation (AF)., Methods: Patients with long-standing persistent AF underwent our modified mini-maze procedure using bipolar radiofrequency ablation. Those patients first underwent a mini-maze procedure using the Dallas lesion set protocol. Second, a purse-string suture was performed on the right atrium, and then 4 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 and 12 months and every year thereafter., Results: A total of 102 patients were included in the study. There were no deaths, no surgical re-exploration for bleeding and no permanent pacemaker implants. The intraoperative cardioversion rate was 42.2% (43/102). A follow-up at intervals of 3, 6, 12, 24, 36 and 48 months showed that a success rate free from long-standing persistent AF 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), whereas freedom from AF in patients 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 procedure proved to be safe and feasible. Early follow-up demonstrated an acceptable success rate free from AF., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)

Background Autonomic ganglionated plexi (GPs) play a significant role in the initiation and maintenance of atrial fibrillation (AF). GPs are key targets for a maze procedure. The purpose of this study was to identify the location of the left atrial GPs based on dense epicardial mapping during a maze procedure in patients with concomitant AF. Methods Sixteen patients (age, 68 ± 10 years; 11 males, 69%) with heart failure and concomitant AF (duration 55 ± 86 months) underwent intraoperative epicardial electrophysiological mapping and a GP ablation using the maze procedure at our institution. Twenty-four-site, high-frequency stimulation (1,000/min; output, 18 V; pulse width, 0.75 ms) was performed by placing tweezers directly onto the potential GP sites on the left atrial epicardium. Results Active GPs were found in 13 (81%) of the 16 patients, and 12 (92%) of 13 patients had active GPs between the right pulmonary veins (PVs) and the interatrial groove. For those patients with active locations, a 7-day event-loop recording demonstrated that 12 (92%) of 13 patients were maintained in sinus rhythm 3 months after the operation. Conclusion Dense epicardial mapping in the potential GP areas identified active GP locations in a high percentage of patients. GPs between the PVs and interatrial groove have a high potential as ablation targets for treatment of concomitant AF. [ABSTRACT FROM AUTHOR]

Although atrial fibrillation is common in cardiac surgery patients, the Cox maze IV procedure is underutilized; in contemporary practice, most cardiac surgery patients with atrial fibrillation do not receive concomitant surgical ablation. Available evidence suggests that a biatrial, energy-assisted Cox maze IV procedure restores normal sinus rhythm in two-thirds to three-quarters of patients without increasing operative risk. The best results are obtained by adherence to the correct lesion set and careful attention to perioperative management of heart rhythm and anticoagulation. To date, we have no randomized clinical trials confirming that surgical ablation improves clinical outcomes beyond restoration of sinus rhythm; however, available evidence does suggest that concomitant surgical ablation provides clinical benefit, most notably by reducing the long-term risk of stroke. [Copyright &y& Elsevier]

Despite its proven efficacy in the treatment of atrial fibrillation (AF), the Cox-Maze III procedure has not been widely accepted owing to its complexity and technical difficulty. New ablation technologies have led to the development of various simplified lesion sets, including minimally invasive techniques. Given recent improvements in the percutaneous catheter ablation technique, it seems to have replaced surgical treatment of AF, especially for lone AF. However, suboptimal results of catheter ablation have been reported, and it has been well established that the Cox-Maze III procedure is still the gold standard for surgical AF ablation. Nevertheless, many physicians and patients are reluctant to undergo surgery for lone AF because of its invasiveness. In this regard, improvements in minimally invasive technology should be directed toward replicating the original Cox-Maze III technique and ultimately on performing it on the beating heart without cardiopulmonary bypass. This review provides an overview of the current state of the art and future directions in the surgical treatment of AF. Based on a better understanding of the mechanisms of AF and various treatment techniques, and improvements in diagnostic techniques, the appropriate option among various surgical techniques should be selected tailored to individual patients, making the surgical treatment of AF available to a larger population of patients. [ABSTRACT FROM AUTHOR]

Background and Objective: Our study aimed to elucidate the potential clinical and molecular issues in recurrent atrial fibrillation (AF) following a radiofrequency modified maze procedure in patients with rheumatic valvular disease and persistent AF. Methods and Results: Eighty patients with rheumatic valvular disease and persistent AF (lasting more than 6 months) who had undergone a radiofrequency modified maze procedure and mitral valve replacement were enrolled into this single-center pilot study and were followed up for another 6 months. Their clinical characteristics were analyzed and the expression of matrix metalloproteinase (MMP)-2 including its specific inhibitor and collagen volume fraction (CVF) was also assessed. During the 6-month follow-up, 24 subjects had recurrent AF. Among them, the left atrial diameter was larger compared to that achieved in sinus rhythm (SR). The mRNA and protein expression of MMP-2 was significantly increased in recurrent AF patients, while its specific inhibitor did not show a significant difference (p > 0.05). The CVF of type I collagen increased significantly in the recurrent AF patients compared to SR patients (18.16 ± 3.22 vs. 11.66 ± 3.38, p < 0.001), whereas the CVF of type III collagen showed no significant difference (8.33 ± 3.44 vs. 9.55 ± 3.67, p > 0.05). Conclusion: This study suggests that the overexpression of MMP-2 is associated with CVF-I in the left atrial appendage which potentially leads to the recurrence of AF following a radiofrequency modified maze procedure in patients with rheumatic valve disease. Copyright © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Abstract: Background: The maze procedure for atrial fibrillation (AF) is effective in restoring sinus rhythm; however, a significant proportion of patients failed to recover atrial mechanical contraction (AMC). We hypothesized that preoperative atrial fibrotic activity would be related to the AMC recovery. Methods: In atrial tissues of 128 consecutive patients who underwent mitral valve and combined maze surgery using cryoablation for persistent AF, preoperative mRNA levels of various biomarkers were measured including transforming growth factor-β1 (TGF-β1), atrial natriuretic peptide, brain natriuretic peptide (BNP), C-reactive protein, connective tissue growth factor, matrix metalloproteinase, N-terminal prohormone BNP, and tissue inhibitor of metalloproteinase. Presence of AMC was assessed using Doppler echocardiographic measurement of the transmitral A-wave velocity. Results: At 1-year follow-up, patients without AMC (n=62) showed higher preoperative TGF-β1 mRNA expression (0.42 versus 0.28, P =0.01) than those with AMC (n=66). There was no significant difference between the two groups regarding the other biomarkers. Recovery rate of AMC and the increment of A-wave velocity were reduced with the increase of preoperative TGF-β1 mRNA level. Multiple logistic regression analysis revealed that TGF-β1 mRNA levels were independently associated with the absence of AMC (odds ratio 7.47, 95% CI 1.63 to 34.4, P =0.01). Conclusions: TGF-β1-mediated atrial fibrotic activity might exert a detrimental effect on the reversibility of atrial mechanical contraction after the maze and combined mitral valve surgery for long-standing persistent AF. Earlier surgical intervention might be needed to preserve atrial mechanical function. [Copyright &y& Elsevier]

OBJECTIVES The aim of this study is to investigate the factors contributing to the progression of functional tricuspid regurgitation (TR) after mitral repair for degenerative mitral regurgitation (MR) in relation to pre and postoperative atrial fibrillation (AF) and performance of the maze procedure. METHODS We assessed 398 patients with less than moderate TR who did not undergo tricuspid valve repair at the time of isolated mitral valve repair for degenerative MR between January 1999 and January 2010. RESULTS Clinical follow-up was complete in 385 patients (96.7%) with a median follow-up of 48.3 months (range 0.13–148.5). During this time, there were 21 late deaths (5.5%) and 17 major complications (4.4%), including 11 reoperations for MR recurrence (2.9%). On late follow-up echocardiography performed on 395 patients (median 44.6 months, range 6.0–147.3), 34 (9.6%) experienced moderate or greater MR and 16 (4.5%) experienced moderate or greater TR. The 5-year freedom from moderate or greater MR and moderate or greater TR rates were 88.3 ± 2.1 and 95.3 ± 1.5%, respectively. Time-updated Cox regression analysis showed that male gender [hazard ratio (HR) 3.83, 95% confidence interval (CI) 1.28–11.40, P = 0.016], New York Heart Association functional class III or IV (HR 2.64, 95% CI 0.88–8.00, P = 0.085), preoperative AF without maze (HR 10.48, 95% CI 2.49–44.21, P = 0.001), and postoperative AF (HR 14.56, 95% CI 4.46–47.58, P < 0.001) were significant risk factors for postoperative moderate or greater TR. Of the 79 patients with preoperative AF, 68 (86.1%) underwent concomitant maze procedures. Of them, eight (11.8%) experienced late AF (>3 months) recurrence. Freedom from AF at 5 years after the concomitant maze procedure was 87.8 ± 4.6%. CONCLUSIONS Preoperative AF without the maze procedure and postoperative AF can contribute to the development of moderate or greater functional TR after mitral repair for degenerative MR. [ABSTRACT FROM AUTHOR]

Objectives: The Cox Maze IV operation is commonly performed concomitant with other cardiac operations and effectively reduces the burden of atrial fibrillation. Prospective randomized trials have reported outcomes early and at 12 months, but only single-center late durability results are available. As part of the postapproval process for a bipolar radiofrequency ablation system, we sought to determine early and midterm outcomes of patients undergoing the Cox Maze IV operation., Methods: A prospective, multicenter, single-arm study of 363 patients (mean age, 70 years, 82% valve surgery) with nonparoxysmal atrial fibrillation (mean duration, 60 months, 94% Congestive heart failure, Hypertension, Age ≥ 75, Diabetes, Stroke, VAScular disease, Age 65-74, Sex category ≥2) undergoing concomitant Maze IV atrial fibrillation ablation at 40 sites with 70 surgeons was performed between June 2010 and October 2014. Compliance with the study lesion set was 94.5%, and 99% had left atrial appendage closure. Freedom from atrial fibrillation was determined by extended monitoring, with a 48-hour Holter monitor minimum., Results: There were no device-related complications. Freedom from atrial fibrillation off antiarrhythmic medications at 1, 2, and 3 years was 66%, 65%, and 64%, respectively, and including those using antiarrhythmics was 80%, 78%, and 76%, respectively. Warfarin was used in 49%, 44%, and 40%, respectively., Conclusions: In patients with nonparoxysmal atrial fibrillation, compliance with the protocol was high, and freedom from atrial fibrillation off antiarrhythmics was high and sustained to 3 years. The safety and effectiveness of the system and Cox Maze IV procedure support the Class I guideline recommendation for concomitant atrial fibrillation ablation in patients undergoing cardiac surgery., (Copyright © 2020 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Background: The efficiency of maze is a safe procedure in AF patients who underwent concomitant mitral valve surgery was more than 60%. The aim of this study was to define predictors of early AF recurrence after concomitant maze procedure with valvular surgery., Methods: In this retrospective study, 234 patients with AF underwent concomitant valvular replacement and maze procedure. Patients were classified into 2 groups of sinus and atrial fibrillation (AF). Baseline characteristics of patients were then compared between 2 groups., Results: Totally, 234 patients were enrolled, 148 of which maintained sinus rhythm during hospitalization. Left atrial diameter and type of valvular surgery were similar in both groups. Age, number of replaced valves, concomitant coronary artery bypass grafting, and history of preoperative persistent AF and beta-blocker therapy were independent predictors of in-hospital AF recurrence. We used these variables to build a model to anticipate early AF recurrence., Conclusions: Being older, multivalvular surgery, and persistent preoperative AF were the predictors of higher risk of early recurrent AF, whereas concomitant coronary artery bypass grafting and using beta-blocker had a protective effect. This model based on preoperative and operative characteristics can help us to better evaluate if the patient benefits from maze procedure coincide with valvular surgery., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Abstract: The development and introduction of radiofrequency ablation devices allowed maze procedure to be performed safely and easily, further enabling off-pump pulmonary vein isolation through mini-thoracotomy or thoracoscopy. The outcomes of the maze procedure include the prevention of stroke and other complications related to atrial fibrillation (AF), improvement in cardiac performance, and relief of symptoms. The indications for the maze procedure have been discussed on the basis of available evidence. Pulmonary vein isolation has been shown to be effective in most patients with paroxysmal AF, and can be performed with both endocardial catheter ablation and minimally invasive epicardial ablation. These 2 modalities should be compared in terms of the success rate, occurrence of cerebral microembolic signals, capability adding other lesions indicated for persistent or long-standing persistent AF, and closure of the left atrial appendage. Noncontinuous or nontransmural lines of conduction block as a result of incomplete ablation can result in the recurrence of AF and induction of atrial tachycardia. Intraoperative verification of a conduction block across the ablation lines is recommended to prevent these complications. Volume reduction of the enlarged left atrium or a box lesion to isolate the entire posterior left atrium may be effective in patients with a dilated left atrium, but the potentially impaired atrial transport function should be considered. Mapping of active ganglionated plexi and their ablation may improve the outcome of the procedure; however, the long-term effect on AF and autonomic nerve activities should be examined. Because the mechanism underlying AF varies in each patient, a tailor-made therapy, using a stepwise approach, with a hybrid procedure combining epicardial and endocardial ablation offers promising prospects in the nonpharmacological treatment of AF. [Copyright &y& Elsevier]

In Framingham cohort study, C-reactive protein was not associated with incident atrial fibrillation (AF) after adjustment for left atrial size. This study examined whether levels of plasma inflammatory markers would be significant risk factors for failed maze procedure for AF. This study enrolled 88 patients with mitral valve disease undergoing valve surgery (n=32, sinus control group) or concomitant maze procedure for persistent atrial fibrillation (AF) (n=56, AF group). The mean follow-up in the AF group was 55.0 ± 17.5 months. The AF and sinus control groups did not differ in preoperative levels of C-reactive protein (p=0.636). In the AF group receiving maze procedure, the sinus conversion (n=37) and non-conversion (n=19) groups did not significantly differ in preoperative levels of interleukin-6 (p=0.607) and tumor necrosis factor-α (p=0.379). In multivariate analysis after adjustment for preoperative plasma inflammatory markers, independent factors associated with sinus conversion were AF duration (p=0.003), and left atrial area (p=0.014). In conclusion, plasma inflammatory markers are not associated with sinus non-conversion by radiofrequency maze procedure. [ABSTRACT FROM AUTHOR]

Background: The advantage of the Maze procedure concomitant with the mechanical valve implantation is unclear. This study evaluated the long-term results of mechanical valve implantation either alone or concomitant with the Maze procedure. Methods: Between 1990 and 2005, 208 patients underwent mitral valve replacement with a mechanical valve. Maze procedure was concomitantly performed in 77 patients, and 54 of these had restored sinus rhythm (Maze group). The other 131 patients did not perform the Maze procedure (non-Maze group). Survival and late outcomes were studied retrospectively with univariate analysis (log-rank test), and a case-matched study by propensity score was performed. The late New York Heart Association (NYHA) functional status obtained by questionnaire and the cardiac function observed by echocardiography were studied for comparison of the two groups. Results: Survival and late outcomes, except for bleeding, were not significantly different between the groups, and this was also true of the case-matched study. In the NYHA functional status, the Maze group had more class I patients, while the non- Maze group has more class II patients. The left ventricular ejection fraction, left atrial enlargement, and tricuspid regurgitation were not significant factors affecting the differences between class I and II patients. Conclusions: The Maze procedure is considered to be worth for patients who need life-long anticoagulation for the mechanical valve because it improves the NYHA functional status. [ABSTRACT FROM AUTHOR]