Development Of Postoperative Atrial Fibrillation Research Articles

Exploring postoperative atrial fibrillation after non-cardiac surgery: mechanisms, risk factors, and prevention strategies.

Atrial fibrillation (AF) stands as the most prevalent persistent arrhythmia and a common complication after surgical procedures. Although the majority of non-cardiac surgery patients experience postoperative AF (POAF) and the condition is typically self-limited and asymptomatic, its detrimental impact on patient outcomes, prolonged hospitalization, and heightened risk of stroke and overall mortality has become increasingly evident. Of significant concern, POAF emerges as a noteworthy risk factor for stroke, myocardial infarction, and mortality in comparison to patients with non-surgical atrial fibrillation. Multiple studies have corroborated the association between POAF and an elevated risk of stroke and mortality. The development of postoperative atrial fibrillation is multifactorial, with the inflammatory response being a primary contributor; additionally, factors such as hypovolemia, intraoperative hypotension, anemia, trauma, and pain can trigger POAF. Risk factors for POAF in non-cardiac surgery primarily relate to age, hypertension, obesity, prior cardiac disease, obstructive sleep apnea, and male sex. Prophylactic treatment with β-blockers, amiodarone, or magnesium has demonstrated efficacy, but further trials are warranted, especially in high-risk populations. This review provides an account of the incidence rate, pathophysiology, and prognosis of atrial fibrillation after non-cardiac surgery, elucidates the underlying mechanisms of its occurrence, and explores various preventive strategies investigated in this domain.

Scoring system for predicting the Post-Operative Atrial Fibrillation (POAF) in post-cardiac surgery: a literature review

Link of Video Abstract: https://youtu.be/tl9Q8g6DUdcBackground: Coronary artery bypass grafting (CABG) is still one of the optimal treatment options for revascularization in coronary heart disease. Despite Atrial Fibrillation being the most common arrhythmia after CABG, there’s still no agreement on which risk assessment to predict the incidence of Post Operative Atrial Fibrillation (POAF).  Some studies have shown that the findings of Atrial fibrillation after CABG are associated with increased hemodynamic disturbances, thromboembolic manifestations, readmission to the Intensive Care Unit (ICU), increased length of stay, organ failure, and death. This study aims to analyze the scoring system used for predicting the incidence of POAF in cardiac surgery. Methods:  This study used “POAF” AND “Scoring system," AND "CABG” AND “Atrial Fibrillation” as keywords to explore the literature from PubMed, Google Scholar, ProQuest, and Clinical Key. Search engines were searched for relevant papers from the last 15 years. Result: CHA2DS2-VASc score has a sensitivity of 74.2%, a specificity of 44.7% and can identify patients who are predicted to have a high risk of experiencing POAF by 49.4%. The CHA2DS2-VASc score can be used as an independent predictor for predicting POAF. HATCH score cut-off point exceeding 1 was linked to AF prediction, yielding a sensitivity of 42% and specificity of 70%. POAF Score, the scoring system anticipates an increased likelihood of POAF development (58.5%). A score of 1 corresponds to a 30.1% probability of POAF occurrence and is a practical point for commencing preventive therapy. Conclusion: Despite the various scoring systems used to predict postoperative atrial fibrillation, including the CHA2DS2-VASc score, HATCH score and Mariscalco. POAF Score demonstrated a validated ability to predict POAF.

311 Mental Illness and the Development of Postoperative Atrial Fibrillation in Transcatheter Aortic Valve Replacement Patients: Trends over Time

OBJECTIVES/GOALS: The purpose of this retrospective cohort study was to evaluate the impact of mental illness on first-time transcatheter aortic valve replacement (TAVR) and repeat TAVR (viv-AVR) outcomes including postoperative atrial fibrillation (POAF/AFL), as well as trends over time. METHODS/STUDY POPULATION: Using de-identified data reports from the New York Statewide Planning and Research Cooperative System (SPARCS) database from 2005-2018, multivariate logistics models were used to predict endpoints including POAF, the Society of Cardiothoracic surgeon (STS) endpoint (MM), and 30-day readmission (READMIT) in patients with and without mental illness. The TAVR procedure was approved for high-risk patients after 2012, and intermediate-risk patients after 2016, indicting a need to analyze the two populations separately. Multivariate analysis was only conducted on the first-time TAVR patients because of the small n in the viv-TAVR population. RESULTS/ANTICIPATED RESULTS: After 2012, 13.05% (1,810/13,870) of patients undergoing TAVR and 20.83% (15/72) undergoing viv-TAVR were diagnosed with a mental illness before the procedure. After 2016, 15.59% (1,485/9,524) TAVR patients and 20.00% (11/55) viv-TAVR patients had a preoperative diagnosis of mental illness. Multivariate analysis showed that mentally ill patients did not have significant differences in rates of POAF, 30-day readmission, and 30-day composite outcomes when compared to patients without mental illnesses following TAVR procedures after 2012 and 2016. Patients with POAF after both 2012 and 2016 were significantly less likely to be mentally ill, Black, and Hispanic. DISCUSSION/SIGNIFICANCE: Of the mentally ill patients who underwent TAVR, there was no significant difference in short-term outcomes after 2012 vs. 2016, compared to patients without mental illnesses. The small number of mentally ill patients undergoing TAVR may point to provider bias as a contributor to this high selectivity, and further evaluation would be of clinical use.

Left Atrial Function as a Predictor for Postoperative Atrial Fibrillation

Background: One of the most frequent complications following heart surgery is atrial fibrillation (AF). The most popular diagnostic procedure for evaluating atrial function is echocardiography, however it has certain drawbacks. Originally, 2D echocardiography has been used to measure volumes to determine left atrial function. Objective: to examine the relationship between the development of post-operative AF following isolated CABG and preoperative evaluation of LA function using 2D echocardiography and left atrium 2D speckle tracking strain echocardiography. Patients and Methods: A set of 149 consecutive patients enrolled in a prospective observational study, they admitted to cardio-thoracic surgery department for elective isolated coronary artery bypass grafting surgery, during July 2018 to June 2019. 22 patients were excluded from the study due to bad image quality. Results: Readings of speckle tracking data showed significant less LA reservoir strain (OR 1.75, 95% CI: 0.65-4.69, P≤0001), LA conduit strains (OR 0.6, 95% CI: 0.22-1.62, P=0.31) and LA contractile strain (OR 0.65, 95% CI: 0.24-1.77, P=0.40) in POAF (+). Remaining parameters were non-significant. Also, Age (P=0.03), LA diameter (P=0.04), and LAVI (P=0.03) were the only factors that were identified as potential predictors of POAF in multivariate logistic regression analysis. Conclusion: we concluded that, age, LA size and LAVI are significantly associated with the occurrence of POAF in our patients.

The Usage of Prognostic Nutritional Index to Predict Postoperative Atrial Fibrillation Development

The Usage of Prognostic Nutritional Index to Predict Postoperative Atrial Fibrillation Development

Association of postoperative atrial fibrillation with higher dosing ratios of protamine-to-heparin.

Background: Postoperative atrial fibrillation (POAF) is defined as new-onset AF in the immediate postoperative period. The relatively high incidence of POAF after cardiac surgery is well described, but pathophysiological mechanisms underlying the initiation, maintenance, and progression of POAF may be multifactorial and have not yet been comprehensively characterized. One of the mechanisms includes altered Ca2+ kinetics. Accumulating evidence has suggested that altered atrial cytosolic calcium handling contributes to the development of POAF, protamine reversibly modulates the calcium release channel/ryanodine receptor 2 (RyR2) and voltage-dependent cardiac RyR2. However, it is currently unknown whether such abnormalities contribute to the arrhythmogenic substrate predisposing patients to the development of POAF. Methods: We have retrospectively analyzed 147 patients who underwent cardiac surgery with cardiopulmonary bypass support. Of these, 40 patients were excluded from the analysis because of pre-existing AF. All patients received heparin followed by protamine at different dosing ratios of protamine-to-heparin, depending on the periods studied. Results: The dosing ratio of protamine-to-heparin=1.0 was compared with higher dosing ratios of protamine-to-heparin >1.0 up to 1.7. POAF developed in 15 patients (15/107=14%), of these, 5 out of 57 patients (33.3%) in the dosing ratio of protamine-to-heparin=1.0 and 10 out of 35 patients (66.7%) in the higher dosing ratios of protamine-to-heparin. Statistical significance was observed in patients with higher dosing ratios of protamine-to-heparin, compared with the dosing ratio of protamine-to-heparin=1.0 (odds ratio=3.890, 95% CI=1.130-13.300, p-value=0.031). When types of diseases were analyzed in terms of higher dosing ratios of protamine-to-heparin, only valvular disorders were significantly associated with POAF (p=0.04). Conclusions: Protamine is clinically utilized to reverse heparin overdose and has been shown to display immunological and inflammatory alterations. However, its association with POAF has not been reported. Our results provide evidence that higher dosing ratios of protamine-to-heparin may increase the incidence of POAF.

Efficacy of tolvaptan in postoperative volume therapy for acute Stanford type A aortic dissection

BackgroundDespite the increasing application of tolvaptan in cardiac surgery, there is no information on the use of tolvaptan in Stanford patients with type A aortic dissection. This study aimed to evaluate the postoperative clinical effects of tolvaptan in patients with type A aortic dissection  after tafter surgery.MethodsA retrospective analysis was performed on 45 patients treated for type A aortic dissection in our hospital from 2018 to 2020. These included 21 patients who were treated with tolvaptan (Group T) and 24 patients who received traditional diuretics (Group L). The hospital's electronic health records were used to obtain perioperative data.ResultsGroup T did not differ significantly from Group L in terms of the duration of mechanical ventilation, postoperative blood required, length of catecholamine use, or the amount of intravenous diuretic drugs administered (all P > 0.05). The development of postoperative atrial fibrillation was significantly less in the tolvaptan group (P = 0.023). The urine volumes and change in body weight loss were slightly higher in group T than in group L but the differences were non-significant (P > 0.05). Serum potassium, creatinine, and urea nitrogen levels did not differ between the groups in the week after surgery, At the same time, sodium was significantly higher in the Group T group on day 7 after transfer from the ICU (P = 0.001). In Group L, sodium levels were also elevated by day 7 (P = 0.001). On days 3 and 7, serum creatinine and urea nitrogen levels increased in both groups (both P < 0.05).ConclusionsBoth tolvaptan and traditional diuretics were found to be effective and safe for patients with acute Stanford type A aortic dissection. Moreover, tolvaptan may be associated with reducing the incidence of postoperative atrial fibrillation.

Investigation of the effect of postoperative early-term high-flow oxygen use on new-onset atrial fibrillation in high-risk patient groups after isolated coronary artery bypass graft operations.

Postoperative atrial fibrillation (PoAF) is a significant complication that may occur after coronary artery bypass graft (CABG) surgeries. High-flow nasal oxygen (HFNO) therapy has recently been used in adult patients. In this current study, we aimed to investigate the effect of early HFNO treatment after extubation on the development of postoperative atrial fibrillation, in patient groups at risk for PoAF. Patients who underwent isolated CABG surgery in our clinic between October 2021 and January 2022 and had a preoperative HATCH score of above 2, were retrospectively included in this study. After the extubation, patients who were followed-up with HFNO were defined as Group 1, and patients who were followed-up with a standard oxygen treatment were determined as Group 2. Group 1 consisted of thirty-seven patients with a median age of 56 (ranging between 37 and 75) years, while Group 2 had seventy-one patients with a median age of 58 (ranging between 41 and 71) years (p=0.357). The groups were similar in terms of gender, hypertension, diabetes mellitus, hypercholesterolemia, smoking, body mass index, and ejection fraction. The need for positive inotropic support and incidence of PoAF was significantly higher in Group 2 (p=0.022, p=0.017, respectively). In this study, we showed that HFNO treatment can reduce the rates of PoAF in high-risk patient groups.

The use of hatch score for the prediction of post operative atrial fibrillation (poaf) after coronary artery bypass graft: a meta-analysis

Abstract Funding Acknowledgements Type of funding sources: None. Background and Aims Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in post-cardiac surgery. It is associated with substantial morbidity and mortality, thus portending a significant burden to patients and the health economy. A HATCH score is a handy tool in predicting new onset atrial fibrillation which consists of (Hypertension &amp;lt;1 point&amp;gt;, Age &amp;gt;75 years old &amp;lt;1 point&amp;gt;, transient ischemic attack or stroke &amp;lt;2 points&amp;gt;, chronic obstructive pulmonary disease [COPD] &amp;lt;1 point&amp;gt;, and heart failure &amp;lt;2 points&amp;gt;. In this study, the authors aimed to determine the role of HATCH score in predicting the occurrence of post-operative atrial fibrillation (PoAF) who had undergone coronary artery bypass graft surgery. Methods We conducted a systematic review and meta-analysis of three studies. The study included patients undergoing cardiac surgery and using HATCH score as a predicting tool for post-operative atrial fibrillation. Results A total of 3 trials eligible for inclusion in our systematic review, giving a total of 908 participants. All three trials used the HATCH score to predict PoAF. The study was done retrospectively. The pooled RR’s showed an important risk for PoAF in patients with a HATCH score of 2 or more, indicating an approximately 2-fold greater risk (RR: 2.86 [95% CI 2.27-3.59], p = 0.00001. Conclusion This study investigated the development of PoAF with reference to the HATCH score. The study demonstrated a correlation of having a high HATCH score and PoAF who had undergone coronary artery bypass surgery.

A Retrospective Study to Evaluate the Association Between the Glasgow Prognostic Score and Atrial Fibrillation, Stroke, and Mortality at 30 Days and at 1 Year After Coronary Artery Bypass Graft Surgery.

BACKGROUND The Glasgow prognostic score (GPS) consists of a combination of serum C-reactive protein and albumin levels as indicators of systematic inflammatory response and nutritional status, respectively. The present retrospective study aimed to evaluate the association between the GPS and atrial fibrillation, stroke, and mortality at 30 days and 1 year after coronary artery bypass graft (CABG) surgery. MATERIAL AND METHODS Patients with chronic coronary syndromes who underwent CABG surgery between 2012 and 2019 in a single center were included. Preoperative GPS was calculated. Then, patients were grouped according to postoperative atrial fibrillation (POAF) development. Further, groups were formed to evaluate the relationship between GPS and 30-day and 1-year cardiovascular mortality as well as stroke development. RESULTS Patients who developed POAF had higher GPS, higher European System for Cardiac Operative Risk Evaluation (EuroSCORE II) score, advanced age, lower angiotensin converting enzyme inhibitor/angiotensin receptor blocker (ACEI/ARB) use, lower left ventricular ejection fraction, and were more likely to be female and to have a history of carotid artery disease (P<0.05, for all). Additionally, GPS, EuroSCORE II, advanced age, and lower left ventricular ejection fraction were detected as independent risk factors for POAF development. When adverse outcomes were assessed, cardiovascular mortality at 30 days or 1 year, and stroke development at 1 year, were more frequent in patients with POAF. Moreover, POAF development was found to be an independent risk factor for adverse outcomes. Also, GPS was established as an independent risk factor both for 30-day and 1-year cardiovascular mortality (P<0.0001 and P=0.001, respectively). CONCLUSIONS GPS is an easy-to-calculate score that has reasonable diagnostic accuracy in determining the risk of POAF and stroke as well as 30-day and 1-year cardiovascular mortality.

Value of Preoperative Platelet-to-Lymphocyte and Neutrophil-to-Lymphocyte Ratios in Predicting Postoperative Atrial Fibrillation in Patients Undergoing Lung Resection.

The aim of this study was to investigate the association between the platelet/lymphocyte ratio (PLR) and the neutrophil/lymphocyte ratio (NLR) and postoperative atrial fibrillation (POAF) after lung resection. After the implementation of the exclusion criteria, 170 patients were retrospectively analyzed. PLR and NLR were obtained from fasting complete blood counts before surgery. POAF was diagnosed using standard clinical criteria. The associations between different variables and POAF, NLR, and PLR were calculated using univariate and multivariate analyses. The receiver operating characteristics (ROC) curve was used to determine the sensitivity and specificity of PLR and NLR. Of the 170 patients, 32 with POAF (mean age =71.28±7.27 y, 28 males and 4 females) and 138 patients without POAF (mean age =64.69±10.31 y, 125 males and 13 females) were identified, and the difference in the mean age was statistically significant (P=0.001). It was found that PLR (157.67±65.04 vs 127.52±56.80; P=0.005) and NLR (3.90±1.79 vs 2.04±0.88; P=0.001) were statistically significantly higher in the POAF group. In the multivariate regression analysis, age, lung resection size, chronic obstructive pulmonary disease, NLR, PLR, and pulmonary arterial pressure were independent risk factors. In the ROC analysis, PLR had a sensitivity of 100% and a specificity of 33% (AUC, 0.66; P<0.001), and NLR had a sensitivity of 71.9% and a specificity of 87.7% (AUC, 0.87; P<0.001). A comparison of AUC between PLR and NLR showed that NLR was statistically more significant (P<0.001). This study showed that NLR was a stronger independent risk factor than PLR for the development of POAF after lung resection.

The Predictive Role of Small Airway Dysfunction in Postoperative Atrial Fibrillation After Isolated Coronary Artery Bypass Surgery.

Atrial fibrillation is the most common arrhythmia following coronary artery bypass graft surgery. The relationship between impaired lung function and atrial fibrillation has been described previously. We aimed to evaluate the prognostic influence of small airway function on predicting postoperative atrial fibrillation undergoing isolated coronary artery bypass graft surgery (CABG). We retrospectively analyzed 283 patients who underwent isolated CABG at our institution between January 2020 and August 2020. The patients were divided into 2 groups according to the development of postoperative atrial fibrillation. Demographic characteristics of the patients were recorded; spirometry was performed for each patient before surgery. Small airway function was determined by forced mid-expiratory flow (forced expiratory flow 25%-75%) values measured by spirometry. Propensity score matching was applied to ensure a balanced distribution of demographic data between the 2 groups. The frequency of postoperative atrial fibrillation was 30.7% in our patient population. After propensity matching, forced expiratory volume in 1 second/forced vital capacity % [80.6 (73.8-87.8) vs. 76.3 (66.7-81.6), P = 0.006] and forced expiratory flow 25%-75% (87.4 ± 14.2 vs. 75.2 ± 15.8, P = 0.001) were significantly lower in postoperative atrial fibrillation group. In multivariate analysis, white blood cell count, left ventricular ejection fraction, cross-clamp time, and forced expiratory flow 25%-75% were found to be independent predictors of postoperative atrial fibrillation development after isolated CABG. In the receiver operating characteristic curve analysis, forced expiratory flow 25%-75% with an optimal threshold value of 81% could detect the presence of postoperative atrial fibrillation with 63.8% sensitivity and 70.1% specificity. Our study demonstrated that small airway obstruction, as indicated by forced expiratory flow 25%-75% in spirometry, can be a simple predictive tool for the development of postoperative atrial fibrillation in patients undergoing isolated CABG.

Скорость окисления крови как предиктор развития фибрилляции предсердий в послеоперационном периоде при проведении шунтирования коронарных артерий

The development of postoperative atrial fibrillation (AF) is associated with surgical trauma, neutrophil activation, pro-inflammatory cytokine release and oxidative stress. Objective: assessment of the prognostic significance of determining blood oxidation rate in relation to the risk of developing atrial fibrillation in the postoperative period during coronary artery bypass surgery. Material and methods. The study included 68 patients with stable coronary heart disease (CHD) who underwent coronary artery bypass surgery under artificial circulation (On-pump), parallel artificial circulation and on the working heart (Off-pump). Indices of induced blood oxidation were studied using biological oxygen monitor, blood oxidation rate was determined. Results. It was found that within the factor model, the rate of blood oxidation is a significant (p &lt; 0.05) component associated with the development of atrial fibrillation (r = 0.90) during surgical myocardial revascularization. According to the results of logistic regression analysis, it was found that the rate of blood oxidation affects the development of atrial fibrillation in the postoperative period of coronary bypass surgery. Conclusions. The rate of blood oxidation is a predictor of atrial fibrillation during coronary artery bypass surgery, regardless of the surgical procedure chosen.

Effect of Aortic Cross-Clamping Time on Development of Postoperative Atrial Fibrillation in Isolated CABG: A Single-Center Prospective Clinical Study

Effect of Aortic Cross-Clamping Time on Development of Postoperative Atrial Fibrillation in Isolated CABG: A Single-Center Prospective Clinical Study

Inflammatory prognostic index predicts new-onset atrial fibrillation and mortality after on-pump coronary artery bypass grafting.

This study aimed to analyze its predictive role in incipient postoperative atrial fibrillation by constructing an inflammatory prognostic index based on hematological and biochemical parameters in patients undergoing elective isolated coronary artery surgery accompanied by cardiopulmonary bypass. The data of 343 patients who underwent coronary bypass surgery between May 2021 and July 2022 were evaluated. Multivariate logistic regression and recipient study characteristic curve analyses were studied by comparing the patients' hematological indices and basic clinical features between the two groups. Logistic regression analysis showed that age (p<0.001), hypertension (p=0.01), and inflammatory prognostic index (p<0.001) were independent predictors of new-onset postoperative atrial fibrillation. To predict the development of postoperative atrial fibrillation, a cutoff value of 0.25 (77.8% sensitivity and 69.3% specificity) was determined for inflammatory prognostic index in the receiver-operating characteristic curve analysis (area under curve=0.798, 95% confidence interval 0.752-0.840). Inflammatory prognostic index can be a noninvasive, easily available marker for predicting new-onset atrial fibrillation after coronary artery bypass surgery.

Desarrollo de fibrilación auricular postoperatoria en pacientes hospitalizados en la unidad de cuidado crítico cardiovascular del Hospital San Vicente Fundación entre el periodo 2011 y 2020

IntroductionAtrial fibrillation is the most common cardiac arrhythmia in critically ill patients and in the postoperative period of cardiac surgery. Its incidence ranges between 20% and 60%. The development of atrial fibrillation in the postoperative period has been associated with deterioration in long-term quality of life, longer hospital stays, increased risk of stroke, infectious, renal, and neurological complications, increased health care costs, and mortality. ObjectiveThe objective of this study was to determine the risk factors associated with the development of atrial fibrillation in the postoperative period of a cohort of patients undergoing cardiovascular surgery between 2011 and 2020. Materials and methodAn observational, analytical case-control study was carried out that included 80 cases and 240 controls (from a cohort of 1010 patients undergoing cardiac surgery). OutcomesPost-surgical atrial fibrillation occurred in 8% of the patients studied. Decompensated heart failure as an event prior to surgery occurred in 27.5% (OR: 1.69; [95% CI: .93-3.04]; p=.079), LVEF<45% (OR: 34; [95% CI: 16-72]; p=.001), being present in 64 cases (80%) and 19 controls (7.9%). ConclusionOlder age, male gender, and chronic obstructive pulmonary disease were the risk factors significantly associated with the development of postoperative atrial fibrillation.

Evaluation of the effect of preoperative HbA1c value on development of postoperative atrial fibrillation in diabetic patients with on-pump coronary artery bypass graft.

We aimed to determine the relationship between hemoglobin A1c (HbA1c) levels and the development of postoperative atrial fibrillation (PoAF). Two hundred and eighty-eightpatients diagnosed with diabetes mellitus and undergoing on-pump coronary bypass were included in the study. Those with serum HbA1c levels between 5.5% and 7.0% were defined as Group 1, those with serum HbA1c levels between 7.1% and 8.9% were defined as Group 2, while those with serum HbA1c levels 9.0% and above formed Group 3. Data between groups were compared. The predictive values of the independent variables for the development of PoAF were measured. We did not finda difference between groups in terms of development PoAF (p = .170).The presence of hypertension was determined as an independent predictor for the development of PoAF (p = .003), but not HbA1c levels (p = .134). There was 50.5% sensitivity and 61.1% specificity for HbA1c values of 9.06% and above to predict PoAF (area under curve: 0.571, p = .049). HbA1c levels were not an independent predictor of PoAF development. However, we think that high HbA1c levels may be a risk factor for the development of PoAF.

Predictive power of elevated preoperative HbA1c levels for postoperative atrial fibrillation in patients undergoing isolated coronary artery bypass surgery-Many questions to be asked and many answers to be given.

The authors performed a detailed retrospective analysis of diabetic patients undergoing isolated coronary artery bypass graft surgery aiming to investigate the association of the preoperative glycosylated hemoglobin with occurrence of postoperative atrial fibrillation. Although statistical analysis showed a weak relationship between HbA1c values of 9.06% or above and postoperative atrial fibrillation(PoAF), they concluded that serum level of HbA1c could not be used as a predictor for the development of PoAF. But there are many questions to be asked and answers to be found.

The ideal environment for the development of postcardiac surgery atrial fibrillation: evidence for endothelial activation and poor cell-cell interaction

Abstract Introduction The development of post-operative atrial fibrillation (POAF) after cardiac surgeryis associated with pre-existing endothelial activation and systemic inflammation due to adhesion and transmigration of leukocytes into the interstitium. The electrical remodelling associated with AF causes changes in connexins, resulting in ineffective electrical coupling between cells and thus ineffective cell-cell communication.There is also an association between the inflammatory state, and the presence of cardiac fibrosis, oxidative stress and myocyte apoptosis. Purpose Our aim was to investigate the pathophysiologicaland regulatory mechanisms of AF through endothelial activation and inflammatory status, as well as cell-cell interactions (connexins) in relation to POAF amongst a cohort of patients undergoing cardiac surgery. Methods We studied prospective patients who underwent CABG (52.9%) or cardiac valve (47.1%) surgery without previous documented AF. Patients with permanent AF who underwent CABG or cardiac valve surgery were also included as positive controls. Plasma samples were collected at baseline and 24 hours after surgery, to assess the impact of surgery. To detect endothelial activation, vascular cell adhesion protein-1 (VCAM-1 (CD106)) was evaluated by ELISA assay in plasma samples. Expression of connexin 40 and 43 were measured by inmunohistochemistry in atrial tissue samples. Results We included 117 patients (75.2% males, median age 67 [IQR 59.5–73.0] years), of whom17 (14.5%) patients had permanent AF; 27 (23.1%) developed POAF and 73 (62.4%) had no AF detected. We found higher baseline VCAM-1 levels versus 24-hour samples overall (p=0.001). When comparing groups, baseline VCAM-1 levels were higher in patients with permanent AF compared to non-AF (p=0.035); and in permanent AF compared to POAF (p=0.049). VCAM-1 levels at 24h followed the same trends between permanent AF and non-AF (p=0.001), and permanent AF versus POAF (p=0.013) (Table 1). VCAM-1 levels over the third tertile (i.e.&amp;gt;49.77 ng/ml) increased the risk of AF almost 3-fold (OR 2.85, 95% CI 1.06–7.70; p=0.039). There was a significant decrease in the expression of connexion 40 in patients with AF (ie. patients with permanent AF or POAF) compared to non-AF patients (1.00 [0.50–2.31] vs. 2.48 [1.94–3.00], p=0.044), while connexin 43 was non-significantly different (1.07 [0.41–1.75] vs. 2.00 [0.63–2.25], p=0.289) (Table 2). Conclusions VCAM-1 levels were upregulated in patients with permanent AF and POAF compared to patients without AF, and remained higher even after surgery, thus demonstrating a relevantendothelial activation. The pro-inflammatory state presented in these patients with AF, along with decreased connexin 40 expression impacting cell-to-cell conduction, suggests a potential combination for atrial remodelling and incident AF. Funding Acknowledgement Type of funding sources: None.

Major Interleukins: Role in the Pathogenesis of Atrial Fibrillation

Interleukins (IL) are a group of cytokines with complex immunomodulatory functions, whereas atrial fibrillation (AF) is the most common cardiac arrhythmia. This review article highlights the role of major IL in the pathogenesis of AF. IL-1 had elevated levels in permanent and persistent AF patients as compared to paroxysmal AF. A study had shown a straightforward connection between the development of postoperative atrial fibrillation and IL-2 sera levels shortly after cardiopulmonary bypass graft for the first time. IL-4 has been involved in anti-inflammatory response and played no role in the contribution of AF. The elevated level of IL-6 rapidly induces atrial electrical remodeling by downregulating cardiac connexins. This change could be significantly increased the risk of AF and related complications during active inflammatory processes. Moreover, a study has shown higher IL-8 levels in permanent AF patients as compared with paroxysmal AF patients. An association was found between IL-10 gene -592A/C polymorphism and AF in Han Chinese. Recombinant human IL-11 therapy shortened atrial refractoriness and also created favorable conditions for AF by an indirect mechanism involving volume expression, stretching of atrial myocardial tissue and sodium retention. An elevated IL-12 expression was observed in the left atrial tissues of AF patients. IL-17 signaling pathway has played a significant role, and some genes could be used as potential therapeutic targets for AF. An association between the risk of AF with single nucleotide polymorphism of IL-18 and also resulted in the increased left atrial diameter and decreased left ventricular ejection fraction in AF subjects as compared to control. IL-27 genetic variants had increased the occurrence of AF. AF patients had elevated levels of IL-37 that were closely linked with AF subgroups.