Surgical treatment of atrial fibrillation in elderly patients undergoing high risk cardiac surgery.

BACKGROUND: Evaluating outcomes of concurrent Cox-Maze procedures in elderly patients undergoing high-risk cardiac surgery. MEHODS: We retrospectively identified patients aged over 70 years with Atrial Fibrillation (AF) from 2011 to 2017 who had two or more other cardiac procedures. They were subdivided into two groups: 1. Cox-Maze IV AF ablation. 2. No-Surgical AF treatment. A propensity match score was used to generate a homogeneous cohort and to eliminate confounding variables. Heart rhythm was assessed from Holter reports or 12-lead ECG. Follow-up data was collected through telephone consultations and medical records. RESULTS: There were 239 patients. Median follow up was 61 months. 70 patients had Cox-Maze IV procedures (29.3%). Demographic, intra- and post-operative outcomes were similar between groups although duration of pre-operative AF was shorter in Cox-Maze group (p = 0.001). There was no significant 30-day mortality difference in propensity matched cohorts (n = 84. P = 0.078). Sinus rhythm at annual and latest follow-up was 84.9% and 80.0% respectively in Maze group - 160 patients (66.9%) were alive at long-term follow-up with good survival outcomes in Cox Maze group. There was a high proportion of patients in NYHA 1 status in Cox-Maze group. No differences observed in freedom from stroke (p = 0.80) or permanent pacemaker (p = 0.33) between the groups. CONCLUSIONS: Surgical ablation is beneficial in elderly patients undergoing high-risk surgery - promoting excellent long-term freedom from AF and symptomatic / prognostic benefits, without added risk. Therefore, surgical risk should not be reason to deny benefits of concomitant AF-ablation. CLINICAL TRIAL REGISTRATION: Not required.

Surgical treatment of atrial fibrillation in mitral valve surgery: a narrative review.

Background and Objective: Atrial fibrillation (AF) is one of the most common arrhythmias in clinical practice, which leads to cardiac decompensation, cardiovascular and cerebrovascular infarction, and other thromboembolic diseases. AF is one of the most common comorbidities of valvular heart disease, especially in mitral valve disease. At the time of their mitral valve surgery, 20-42% of patients have AF. It is beneficial to maintain postoperative sinus rhythm and minimize complications when AF surgery is performed concurrently with mitral valve surgery. This review describes the surgical management of AF in mitral valve surgery, including AF surgical route, surgical ablation technology and surgical approaches. The aim of this review is to enable more patients with AF to receive more appropriate and individualised treatment. Methods: A narrative review was conducted on the literature on PubMed, Embase including all relevant studies published until November 2023. Key Content and Findings: This review focuses on the surgical management of AF during mitral valve surgery, including AF surgical route, surgical ablation technology and surgical approaches. Conclusions: Mitral valve surgery combined with AF surgery facilitates the maintenance of postoperative sinus rhythm in patients, reduces the risk of postoperative stroke, and improves survival. Advances in ablation technology have reduced the difficulty of the procedure, making it possible for more patients to undergo surgical ablation. In the future, it will be possible to tailor specific lesion sets and ablation modalities for individual patients. This would make surgical treatment of AF more effective and applicable to a larger population of patients with AF and mitral valve disease.

Efficacy of a Surgical Cardiac Ablation Clamp using Nanosecond Pulsed Electric Fields: An Acute Porcine Model.

OBJECTIVE: This study examined the effectiveness of a recently developed non-thermal technology, nanosecond pulse field ablation (nsPFA), for surgical ablation of the atria in a beating heart porcine model. METHODS: Six pigs underwent sternotomy and ablation using an nsPFA parallel clamp. The ablation electrodes (53 mm long) were embedded in the jaws of the clamp. Nine lesions per pig were created in locations chosen to be representative of the Cox-Maze procedure. Four lesions were intended to electrically isolate parts of the atrium: the right atrial appendage, left atrial appendage, right pulmonary veins, and left pulmonary veins. For these lesions, exit block testing was performed both after ablation and before euthanasia; the time between the two tests was 3.3±0.5 hours (range 2 to 4 hours). Using purse string sutures, five more lesions were created up to the superior vena cava, down to the inferior vena cava, across the right atrial free wall, and at two distinct locations on the left atrial free wall. The clamp delivered a train of nanosecond duration pulses, with a total duration of 2.5 s, independent of tissue thickness. The heart tissue was stained with 1% triphenyltetrazolium chloride (TTC) after a dwelling period of two hours. Subsequently, each lesion was cross sectioned at 5 mm intervals to assess the ablation depth and transmurality. In some sections, transmurality could not be established on the basis of TTC staining alone; for these lesions, Gomori-trichrome stains were used, and the histological sections were evaluated for transmurality. RESULTS: The ablation time was 2.5 seconds per lesion, for a total of only 22.5 seconds ablation time to create 9 lesions. A total of 53 lesions were created, resulting in 388 separate histological sections. Transmurality was established in 386 sections (99.5%). Mean tissue thickness was 3.1±1.5 mm (range of 0.2 mm to 8.6 mm). Exit block was confirmed in 23 of the 24 lesions (96%) post-ablation and 23/24 (96%) pre-euthanasia. Over the course of the procedure, neither pulse-induced arrhythmias nor any other complications were noted. CONCLUSIONS: The novel nsPFA clamp device was effective in creating acute conduction block and transmural lesions in both the right and left atria in an acute porcine model. This non-thermal energy source has great potential to both shorten procedural time and enable effective ablation in the beating heart.

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.

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.

The outcomes of concomitant catheter ablation in non-mitral valve cardiac surgery-a systematic review and meta-analysis of the literature.

Background: Atrial fibrillation (AF) is the most common form of cardiac arrythmia, with a key importance in the perioperative setting of cardiac surgery. In recent years, the question as to whether pre-existent AF should be treated concomitantly when undergoing cardiac surgery has been heatedly debated. This systematic review and meta-analysis sought to delineate the outcomes of patients undergoing concomitant AF ablation procedures alongside cardiac surgery. Methods: The methods for this systematic review and meta-analysis adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement. Four databases were searched, ultimately yielding 22 papers for inclusion, using appropriate search terminology. Meta-analysis using proportions or means, as appropriate, were applied. Kaplan-Meier curves were digitized and aggregated using previously reported and validated techniques. Results: A total of 9,428 patients (67% male) were identified across the study period as having received non-mitral cardiac surgery and concomitant AF ablation procedures. On actuarial assessment, freedom from AF was found to be 93%, 88%, 85%, 82%, and 79% at 1 through to 5 years, respectively. Freedom from mortality was found to be 94%, 93%, 91%, 90%, and 87% at 1 through to 5 years, respectively. Conclusions: This review demonstrated excellent freedom from AF out to a long-term follow-up of 5 years. Freedom from mortality was also encouraging. Emerging data are increasingly illustrating that in this patient cohort, concurrent treatment of pre-existent AF with cardiac and/or valvular disease at the point of operation should be the standard of care. Robust data in the form of randomized control trials will hopefully solidify this assertion.

Surgical options for atrial fibrillation treatment during concomitant cardiac procedures.

Current guidelines recommend concomitant surgical ablation (SA) of atrial fibrillation (AF) in the context of mitral valve disease. A variety of energy sources have been tested for SA to perform effective transmural lesions reliably. To date, only radiofrequency and cryothermy energies are considered viable options. The gold standard for SA is the Cox-Maze ablation set, especially for non-paroxysmal AF (nPAF), with the aim of interrupting macro-reentrant drivers perpetuating AF, without hampering the sinus node activation of both atria, and to maintain the atrioventricular synchrony. Although the efficacy of SA in terms of early and late sinus rhythm restoration has been clearly demonstrated over the years, concomitant AF ablation is still underperformed in patients with AF undergoing cardiac surgery. From a surgical standpoint, concerns have been raised about whether a single (left) or double atriotomy would be justified in AF patients undergoing a "non-atriotomy" surgical procedure, such as aortic valve or revascularization surgery. Thus, an array of simplified lesion sets have been described in the last decade, which have unavoidably hampered procedural efficacy, somewhat jeopardizing the standardization process of ablation surgery. As a matter of fact, the term "Maze" has improperly become a generic term for SA. Surgical interventions that do not align with the principles of forming conduction-blocking lesions according to the Maze pattern, cannot be classified as Maze procedures. In this complex scenario, a tailored approach according to the different AF patterns has been proposed: for patients with concomitant nPAF, a biatrial Cox-Maze ablation is recommended. Conversely, it might be reasonable to limit lesions to the left atrium or the pulmonary veins in patients with paroxysmal AF (PAF) in some clinical scenarios. The aim of this review is to provide an overview of the current ablation strategies for patients with AF undergoing concomitant cardiac surgery.

Effectiveness of Maze IV procedure versus thoracoscopic ablation for atrial fibrillation: a propensity score-matched analysis.

Background: Thoracoscopic ablation (TA) has emerged as a promising treatment for atrial fibrillation (AF), with the Cox-Maze IV Procedure (CMP-IV) as the current gold-standard intervention. This study aims to evaluate and compare the outcomes of TA and CMP-IV in treating AF. Methods: Patients with AF underwent either CMP-IV or TA through a left-side chest approach. The CMP-IV entailed bi-atrium ablation, whereas the TA involved creating three circular plus three linear ablations in the left atrium. We analyzed baseline characteristics, perioperative outcomes and recurrence rates using propensity score matching (PSM) at a 1:1 ratio, to ensure comparability between the two treatment groups. Results: A total of 459 patients underwent either CMP-IV (n=93) or TA via left chest (n=366) and 174 patients were deemed eligible for 1:1 PSM. The TA group experienced significantly shorter intensive care unit (ICU) and hospital stays. The mean follow-up period was 31.5±22.1 months. Pre- and post-matching analysis showed that CMP-IV had a higher rate of freedom from recurrence compared to TA, particularly in non-paroxysmal AF patients. Multivariable Cox regression analysis revealed that CMP-IV was associated with a reduced risk of recurrence, while an increased left atrial size emerged as an independent predictor of postoperative recurrence, regardless of the use of CMP-IV or TA. Conclusions: Our study suggests that while the therapeutic efficacy of TA for "lone" AF may fall short of the classic CMP-IV, its less invasive nature results in significantly shorter ICU and hospital stays. To enhance patient outcomes following TA, it is essential to improve the quality of ablation, refine the ablation route, and focus on careful patient selection.

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

BACKGROUND: Cox-Maze procedure is currently the gold standard treatment for atrial fibrillation (AF). However, data on the effectiveness of the Cox-Maze procedure after concomitant mitral valve surgery (MVS) are not well established. The aim of this study was to assess the safety and efficacy of Cox-Maze procedure versus no-maze procedure n in AF patients undergoing mitral valve surgery through a systematic review of the literature and meta-analysis. METHODS: A systematic search on PubMed/MEDLINE, EMBASE, and Cochrane Central Register of Clinical Trials (Cochrane Library, Issue 02, 2017) databases were performed using three databases from their inception to March 2023, identifying all relevant randomized controlled trials (RCTs) comparing Cox-Maze procedure versus no procedure in AF patients undergoing mitral valve surgery. Data were extracted and analyzed according to predefined clinical endpoints. RESULTS: Nine RCTs meeting the inclusion criteria were included in this systematic review with 663 patients in total (341 concomitant Cox-Maze with MVS and 322 MVS alone). Across all studies with included AF patients undergoing MV surgery, the concomitant Cox-Maze procedure was associated with significantly higher sinus rhythm rate at discharge, 6 months, and 12 months follow-up when compared with the no-Maze group. Results indicated that there was no significant difference between the Cox-Maze and no-Maze groups in terms of 1 year all-cause mortality, pacemaker implantation, stroke, and thromboembolism. CONCLUSIONS: Our systematic review suggested that RCTs have demonstrated the addition of the Cox-Maze procedure for AF leads to a significantly higher rate of sinus rhythm in mitral valve surgical patients, with no increase in the rates of mortality, pacemaker implantation, stroke, and thromboembolism.

Mid-to-long-term recurrence of atrial fibrillation in surgical treatment vs. catheter ablation: a meta-analysis using aggregated survival data.

Background: Atrial fibrillation (AF) is the most common cardiac arrhythmia and leading cardiac cause of stroke. Catheter and surgical ablation are two techniques used currently to resolve prolonged disease by limiting the excitatory potential of specific areas of myocardium in the atria of the heart. The aim of this systematic review and meta-analysis was to provide a graphical amalgamation of mid-to-long-term rhythm outcomes following transcatheter and surgical intervention, whether primary or concomitant ablation. Methods: Three electronic databases were selected to complete the initial literature search from inception of records until April 2023. Primary outcomes were freedom from AF at 12 months, as well as long term time-to-event recurrence data. These data were calculated using aggregated Kaplan-Meier curves according to established methods. The secondary outcome was procedural time for each ablation method. Results: Following independent screening, 36 studies were included for analysis. A total of 6,700 patients were followed, of whom 4,863 (72.6%) were male. Freedom from AF recurrence at 1, 3 and 5 years for the surgical cohort was 71.7%, 57.6% and 47.6%, respectively. Comparatively, the recurrence rates of the catheter ablation cohort at 1, 3 and 5 years were 71.5%, 56.5% and 50.3%, respectively. Conclusions: Despite potentially more complex diseases, surgical ablation patients have non-inferior long-term AF recurrence when compared to those undergoing catheter ablation. Recurrence at 12 months as well as procedural time are also similar between these groups. Ultimately, both ablation methods were able to prevent recurrence of AF in approximately 50% of patients at five years following the procedure.

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.

[Surgical concepts for atrial fibrillation in patients with concomitant mitral valve disease]. / Sravnitel'nyi analiz dvukh kontseptsii khirurgicheskogo lecheniya fibrillyatsii predserdii u patsientov s soputstvuyushchim porazheniem mitral'nogo klapana.

OBJECTIVE: To analyze in-hospital results after «Cox-maze III¼ and «Cox-maze IV¼ procedures with concomitant mitral valve surgery. MATERIAL AND METHODS: This study included patients who underwent «Cox-maze III¼ and «Cox-maze IV¼ procedures between January 2015 and February 2022. We distinguished 2 groups using propensity score matching: «Cox-maze III¼ group (n=15), «Cox-maze IV¼ group (n=14). All patients had preoperative atrial fibrillation: paroxysmal (3 (10.3%) patients), persistent (5 (17.2%)) and long-standing persistent (21 (72.4%) patients). Mean duration of AF before surgery was 11 [9-60] months in both groups. We used standard statistical methods using the IBM SPSS Statistics 26.0 software package (USA). RESULTS: Aortic cross-clamping time was significantly less in the «Cox-maze IV¼ group (p<0.001). There was no in-hospital mortality in both groups. Mean duration of mechanical ventilation was significantly less in the «Cox-maze IV¼ group (5 [3.5-9] vs. 14 [12-18] hours, respectively, p<0.001). Drainage output in the first postoperative day was significantly less in the «Cox-maze IV¼ group (295 [220-370] vs. 400 [325-500] ml, respectively, p=0.02). Temporary pacemaker was required in 73.3% and 42.8% of cases, respectively (p=0.03). CONCLUSION: We should emphasize high efficiency of sinus rhythm recovery after both procedures without significant difference (p=0.16). However, time of aortic cross-clamping, mechanical ventilation and volume of postoperative bleeding were significantly less in the «Cox-maze IV¼ group.

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. / åŸºäºŽæœºå™¨å­¦ä¹ çš„æ ¢æ€§ç“£è†œç— åˆå¹¶å¿ƒæˆ¿é¢¤åŠ¨æ‚£è€ è¡ŒCox迷宫IV手术后心房颤动复发风险预测模型.

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.

Massive Atrial Thrombosis: A Serious Complication of the Maze Procedure Triggered by Heparin-Induced Thrombocytopenia (HIT).

Atrial fibrillation is one of the most common cardiac arrhythmias, classically presenting with an "irregularly irregular" rhythm with or without chest pain, palpitations, shortness of breath, lightheadedness, or fatigue. The maze procedure is an open-heart operation that creates a carefully designed maze of incisions and ablations in the atrial myocardium. Although it is a common procedure, serious complications may happen. Herein, we report on a 76-year-old man who presented with chest pain and atrial fibrillation and was found to have multi-vessel disease on a coronary angiogram. He underwent coronary artery bypass and the COX-maze procedure, which was complicated by a massive thrombosis in the atria and the superior vena cava following the ablation line, secondary to heparin-induced thrombocytopenia, which is extremely rare. The central focus of this paper is to present this rare complication to stress the importance of rigorous follow-up and anticoagulation therapy in patients undergoing the maze procedure. To our knowledge, we are the first to report such a rare case of diffuse large atrial thrombi triggered by heparin-induced thrombocytopenia (HIT) type II after a COX-maze procedure.

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.

Sinus node dysfunction and related permanent pacemaker implantation after major cardiac surgeries, systematic review, and meta-analysis.

Background: There is no concise evidence or clinical guidelines regarding the incidence of sinus node dysfunction (SND) and permanent pacemaker (PPM) implantation following cardiac surgeries and their management approaches. Objective: We aim to systematically review current evidence on the prevalence of SND, PPM implantation concerning it, and its risk factors in patients undergoing cardiac surgery. Method: Four electronic databases (Cochrane Library, Medline, SCOPUS, and Web of Science) were systematically searched for articles regarding SND after cardiovascular surgeries and reviewed by two independent researchers, and a third review in case of discrepancies. Using the random-effects model, a proportion meta-analysis was performed on data regarding PPM implantation. Subgroup analysis was performed for different interventions, and the possible effect of different covariates was evaluated using meta-regression. Results: From the initial 2012 unique records, 87 were included in the study, and results were extracted. Pooled data from 38,519 patients indicated that the overall prevalence of PPM implantation due to SND after cardiac surgery was 2.87% (95% CI [2.09; 3.76]). The incidence of PPM implantation in the first post-surgical month was 2.707% (95% CI [1.657; 3.952]). Among the four main intervention groups, including valve, maze, valve-maze, and combined surgeries, maze surgery was associated with the highest prevalence (4.93%; CI [3.24; 6.92]). The pooled prevalence of SND among studies was 13.71% (95% CI [8.13; 20.33]). No significant relationship was observed between PPM implantation and age, gender, cardiopulmonary bypass time, or aortic cross-clamp time. Conclusion: Based on the present report, patients undergoing the maze and maze-valve procedures are at higher risk of post-op SND, whereas lone valve surgery had the lowest prevalence of PPM implantation. Systematic Review Registration: PROSPERO (CRD42022341896).