Environmental Exposome and Atrial Fibrillation: Emerging Evidence and Future Directions.

There has been increased awareness of the linkage between environmental exposures and cardiovascular health and disease. Atrial fibrillation is the most common sustained cardiac arrhythmia, affecting millions of people worldwide and contributing to substantial morbidity and mortality. Although numerous studies have explored the role of genetic and lifestyle factors in the development and progression of atrial fibrillation, the potential impact of environmental determinants on this prevalent condition has received comparatively less attention. This review aims to provide a comprehensive overview of the current evidence on environmental determinants of atrial fibrillation, encompassing factors such as air pollution, temperature, humidity, and other meteorologic conditions, noise pollution, greenspace, and the social environment. We discuss the existing evidence from epidemiological and mechanistic studies, critically evaluating the strengths and limitations of these investigations and the potential underlying biological mechanisms through which environmental exposures may affect atrial fibrillation risk. Furthermore, we address the potential implications of these findings for public health and clinical practice and identify knowledge gaps and future research directions in this emerging field.

Periodontal Treatment During the Blanking Period Improves the Outcome of Atrial Fibrillation Ablation.

BACKGROUND: Periodontitis has not been recognized as a modifiable risk factor for atrial fibrillation (AF). This prospective nonrandomized study investigated whether periodontal treatment improves the AF ablation outcome. METHODS AND RESULTS: We prospectively enrolled 288 AF patients scheduled to undergo initial radiofrequency catheter ablation. Each patient underwent periodontal inflamed surface area (PISA; a quantitative index of periodontal inflammation) measurement. All eligible patients were recommended to receive periodontal treatment within the blanking period, and 97 consented. During the mean follow-up period of 507±256 days, 70 (24%) AF recurrences were documented. Patients who exhibited AF recurrences had a higher PISA than those who did not (456.8±403.5 versus 277.7±259.0 mm2, P=0.001). These patients were categorized into high-PISA (>615 mm2) and low-PISA (<615 mm2) groups according to the receiver operating characteristic analysis for AF recurrence (area under the curve, 0.611; sensitivity, 39%; specificity, 89%). A high PISA, as well as female sex, AF duration, and left atrial volume, were the statistically significant predicter for AF recurrence (hazard ratio [HR], 2.308 [95% CI, 1.234-4.315]; P=0.009). In patients with a high PISA, those who underwent periodontal treatment showed significantly fewer AF recurrences (P=0.01, log-rank test). The adjusted HR of periodontal treatment for AF recurrence was 0.393 (95% CI, 0.215-0.719; P=0.002). CONCLUSIONS: Periodontitis may serve as a modifiable risk factor for AF. PISA is a hallmark of AF recurrence, and periodontal treatment improves the AF ablation outcome, especially for those with poor periodontal condition.

Exploring the association between regional fat distribution and atrial fibrillation risks: a comprehensive cohort study.

Background: The contribution of total fat mass and regional fat distribution to the risk of AF has rarely been studied. Methods: This prospective cohort study(N=494,063) evaluated the association of total fat mass measured by fat percentage (FP) and regional fat measured by arm fat percentage (AFP), trunk fat percentage (TFP), and leg fat percentage (LFP) with incident AF. A subgroup (N = 25,581) underwent MRI, which allowed us to further assess whether visceral adipose tissue (VAT) and abdominal subcutaneous adipose tissue (ASAT) of the trunk fat exert different effects on AF incidence. Results: Over, a median 12.9 ± 1.86 years of follow-up, 29,658 participants (cumulative rate: 6.0%) developed AF. Each 1-standard deviation (SD) increase in LFP was associated with a 16% lower risk of AF (HR: 0.84, 95% CI: 0.82, 0.85). The association between FP and AF was weaker than that between LFP and AF (HR: 0.90, 95% CI: 0.89, 0.92). AFP and TFP only had a marginal association with a lower incidence of AF. Both the VAT and ASAT showed a U-shaped relationship with incident AF. Conclusions: Fat mass, mainly leg fat mass, was associated with a lower risk of AF. ASAT did not exert protective effects.

Impact of atrial fibrillation phenotype and left atrial volume on outcome after pulmonary vein isolation.

AIMS: Pulmonary vein isolation (PVI) is increasingly performed in patients with atrial fibrillation (AF). Both AF phenotype and left atrial (LA) volume have been shown to influence ablation outcome. The inter-relationship of the two is incompletely understood. We aimed to investigate the impact of AF phenotype vs. LA volume on outcome after PVI. METHODS AND RESULTS: In a retrospective analysis of a prospective registry of patients undergoing a first PVI, the association of AF phenotype and LA volume index (LAVI) was assessed as well as their impact on AF recurrence during follow-up. Overall, 476 patients were enrolled (median age 63 years, 29% females, 65.8% paroxysmal AF). Obesity, hypertension, chronic kidney disease, and heart failure were all significantly more frequent in persistent AF. After 1 year, single-procedure, freedom from arrhythmia recurrence was 61.5%. Patients with paroxysmal AF had better outcomes compared with patients with persistent AF (65.6 vs. 52.7%, P = 0.003), as had patients with no/mild vs. moderate/severe LA dilation (LAVI <42 mL/m2 67.1% vs. LAVI ≥42 mL/m2 53%, P < 0.001). The combination of both parameters refined prediction of 1-year recurrence (P < 0.001). After adjustment for additional clinical risk factors in multivariable Cox proportional hazard analysis, both AF phenotype and LAVI ≥42 mL/m2 contributed significantly towards the prediction of 1-year recurrence. CONCLUSION: Atrial fibrillation phenotype and LA volume are independent predictors of outcome after PVI. Persistent AF with no/mild LA dilation has a similar risk of recurrence as paroxysmal AF with a moderate/severe LA dilation and should be given similar priority for ablation.

Association between triglyceride-glucose index trajectories and radiofrequency ablation outcomes in patients with stage 3D atrial fibrillation.

BACKGROUND: This study investigates the relationship between triglyceride-glucose (TyG) index trajectories and the results of ablation in patients with stage 3D atrial fibrillation (AF). METHODS: A retrospective cohort study was carried out on patients who underwent AF Radiofrequency Catheter Ablation (RFCA) at the Cardiology Department of the Fourth Affiliated Hospital of Zhejiang University and Taizhou Hospital of Zhejiang Province from January 2016 to December 2022. The main clinical endpoint was determined as the occurrence of atrial arrhythmia for at least 30 s following a 3-month period after ablation. Using a latent class trajectory model, different trajectory groups were identified based on TyG levels. The relationship between TyG trajectory and the outcome of AF recurrence in patients was assessed through Kaplan-Meier survival curve analysis and multivariable Cox proportional hazards regression model. RESULTS: The study included 997 participants, with an average age of 63.21 ± 9.84 years, of whom 630 were males (63.19%). The mean follow-up period for the participants was 30.43 ± 17.75 months, during which 200 individuals experienced AF recurrence. Utilizing the minimum Bayesian Information Criterion (BIC) and the maximum Entropy principle, TyG levels post-AF RFCA were divided into three groups: Locus 1 low-low group (n = 791), Locus 2 low-high-low group (n = 14), and Locus 3 high-high group (n = 192). Significant differences in survival rates among the different trajectories were observed through the Kaplan-Meier curve (P < 0.001). Multivariate Cox regression analysis showed a significant association between baseline TyG level and AF recurrence outcomes (HR = 1.255, 95% CI: 1.087-1.448). Patients with TyG levels above 9.37 had a higher risk of adverse outcomes compared to those with levels below 8.67 (HR = 2.056, 95% CI: 1.335-3.166). Furthermore, individuals in Locus 3 had a higher incidence of outcomes compared to those in Locus 1 (HR = 1.580, 95% CI: 1.146-2). CONCLUSION: The TyG trajectories in patients with stage 3D AF are significantly linked to the outcomes of AF recurrence. Continuous monitoring of TyG levels during follow-up may help in identifying patients at high risk of AF recurrence, enabling the early application of effective interventions.

Bronchogenic cyst: a rare cause of palpitations and atrial fibrillation.

Bronchogenic cysts are rare congenital lesions found primarily in the mediastinum. Most patients are asymptomatic and can be treated with minimally invasive resection. We present a case of a middle-aged patient who presented to a district general hospital with palpitations and shortness of breath. She underwent a computerised tomographic pulmonary angiogram that showed a likely bronchogenic cyst and was subsequently transferred to our hospital. She developed atrial fibrillation during admission requiring therapy with beta-blockers and digoxin. Cardiac MRI revealed a large cyst posterior to the left atrium, a moderate circumferential pericardial effusion and bilateral pleural effusions. There was significant left atrial compression. The patient underwent surgical removal of the cyst and was discharged. She returned to the hospital within a week with palpitations and was treated with intravenous antibiotics for sepsis. She was discharged a week later and remained clinically stable.

Atrial secondary tricuspid regurgitation: pathophysiology, definition, diagnosis, and treatment.

Atrial secondary tricuspid regurgitation (A-STR) is a distinct phenotype of secondary tricuspid regurgitation with predominant dilation of the right atrium and normal right and left ventricular function. Atrial secondary tricuspid regurgitation occurs most commonly in elderly women with atrial fibrillation and in heart failure with preserved ejection fraction in sinus rhythm. In A-STR, the main mechanism of leaflet malcoaptation is related to the presence of a significant dilation of the tricuspid annulus secondary to right atrial enlargement. In addition, there is an insufficient adaptive growth of tricuspid valve leaflets that become unable to cover the enlarged annular area. As opposed to the ventricular phenotype, in A-STR, the tricuspid valve leaflet tethering is typically trivial. The A-STR phenotype accounts for 10%-15% of clinically relevant tricuspid regurgitation and has better outcomes compared with the more prevalent ventricular phenotype. Recent data suggest that patients with A-STR may benefit from more aggressive rhythm control and timely valve interventions. However, little is mentioned in current guidelines on how to identify, evaluate, and manage these patients due to the lack of consistent evidence and variable definitions of this entity in recent investigations. This interdisciplinary expert opinion document focusing on A-STR is intended to help physicians understand this complex and rapidly evolving topic by reviewing its distinct pathophysiology, diagnosis, and multi-modality imaging characteristics. It first defines A-STR by proposing specific quantitative criteria for defining the atrial phenotype and for discriminating it from the ventricular phenotype, in order to facilitate standardization and consistency in research.

Vigorous physical activity and atrial fibrillation in healthy individuals: What is the correct approach?

Sport activity compared to sedentary life is associated with improved wellbeing and risk reduction in many different health conditions including atrial fibrillation (AF). Vigorous physical activity is associated with increased AF risk. We describe four individuals, who regularly perform endurance sport activity and developed AF. We discuss the changes occurring in the heart of endurance athletes and the possible etiology for AF, as well as currently available treatment options in this seemingly healthy population. Although the etiology of AF in the general population differs from the one in the usually younger endurance sport activity population, the treatment options are similar. There are several factors unique to those involved in vigorous physical activity that can influence their management. Despite a lack of evidence, endurance athletes with AF have traditionally been advised to "de-training," to reduce both the amount and intensity of exercise. Some of the current offered treatment options (beta-blockers, class III antiarrhythmic) have a varied range of adverse effect, hindering them unattractive for these individuals. Depending on risk stratification tools, anticoagulation may be indicated. Some suggest an intermittent dosing therapy, while others recommend following current guidelines. AF ablation is recommended in exercising individuals with recurrent, symptomatic AF and/or in those who do not want drug therapy, given its impact on athletic performance, AF treatment decisions should be individualized for those engaging vigorous physical activity, while considering the potential risks, the urgency of returning to training, and the will and expectations of the patient.

Impact of maintaining serum potassium concentration ≥ 3.6mEq/L versus ≥ 4.5mEq/L for 120 hours after isolated coronary artery bypass graft surgery on incidence of new onset atrial fibrillation: Protocol for a randomized non-inferiority trial.

BACKGROUND: Atrial Fibrillation After Cardiac Surgery (AFACS) occurs in about one in three patients following Coronary Artery Bypass Grafting (CABG). It is associated with increased short- and long-term morbidity, mortality and costs. To reduce AFACS incidence, efforts are often made to maintain serum potassium in the high-normal range (≥ 4.5mEq/L). However, there is no evidence that this strategy is efficacious. Furthermore, the approach is costly, often unpleasant for patients, and risks causing harm. We describe the protocol of a planned randomized non-inferiority trial to investigate the impact of intervening to maintain serum potassium ≥ 3.6 mEq/L vs ≥ 4.5 mEq/L on incidence of new-onset AFACS after isolated elective CABG. METHODS: Patients undergoing isolated CABG at sites in the UK and Germany will be recruited, randomized 1:1 and stratified by site to protocols maintaining serum potassium at either ≥ 3.6 mEq/L or ≥ 4.5 mEq/L. Participants will not be blind to treatment allocation. The primary endpoint is AFACS, defined as an episode of atrial fibrillation, flutter or tachycardia lasting ≥ 30 seconds until hour 120 after surgery, which is both clinically detected and electrocardiographically confirmed. Assuming a 35% incidence of AFACS in the 'tight control group', and allowing for a 10% loss to follow-up, 1684 participants are required to provide 90% certainty that the upper limit of a one-sided 97.5% confidence interval (CI) will exclude a > 10% difference in favour of tight potassium control. Secondary endpoints include mortality, use of hospital resources and incidence of dysrhythmias not meeting the primary endpoint (detected using continuous heart rhythm monitoring). DISCUSSION: The Tight K Trial will assess whether a protocol to maintain serum potassium ≥ 3.6 mEq/L is non inferior to maintaining serum potassium ≥ 4.5 mEq/L in preventing new-onset AFACS after isolated CABG. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04053816. Registered on 13 August 2019. Last update 7 January 2021.

Flecainide causing elevated capture thresholds on pacemaker implantation.

Flecainide is a Vaughan Williams class 1c antiarrhythmic used to treat supraventricular and ventricular arrhythmias. It has been described as a rare cause for increased pacemaker capture thresholds. We describe a report of a patient, in her early 80s, presenting with tachy-brady syndrome on a background of permanent atrial fibrillation. She was treated with metoprolol and flecainide by her private cardiologist. Permanent right ventricular chamber pacing was recommended for her slow heart rate. At insertion of her single chamber pacemaker, she was noted to have elevated capture thresholds despite appropriate lead positioning. A flecainide level was elevated at 1.1 µg/mL, and it was subsequently ceased. This was associated with a rapid improvement in her capture threshold. Flecainide should be considered as a cause for elevated pacing thresholds at the time of implant. Particular care should be taken for at-risk groups such as the elderly and patients with renal impairment.

Recurrence of Atrial Fibrillation in Patients With New-Onset Postoperative Atrial Fibrillation After Coronary Artery Bypass Grafting.

Importance: New-onset postoperative atrial fibrillation (POAF) occurs in approximately 30% of patients undergoing coronary artery bypass grafting (CABG). It is unknown whether early recurrence is associated with worse outcomes. Objective: To test the hypothesis that early AF recurrence in patients with POAF after CABG is associated with worse outcomes. Design, Setting, and Participants: This Swedish nationwide cohort study used prospectively collected data from the SWEDEHEART (Swedish Web System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies) registry and 3 other mandatory national registries. The study included patients who underwent isolated first-time CABG between January 1, 2007, and December 31, 2020, and developed POAF. Data analysis was performed between March 6 and September 16, 2023. Exposure: Early AF recurrence defined as an episode of AF leading to hospital care within 3 months after discharge. Main Outcomes and Measures: The primary outcome was all-cause mortality. Secondary outcomes included ischemic stroke, any thromboembolism, heart failure hospitalization, and major bleeding within 2 years after discharge. The groups were compared with multivariable Cox regression models, with early AF recurrence as a time-dependent covariate. The hypothesis tested was formulated after data collection. Results: Of the 35 329 patients identified, 10 609 (30.0%) developed POAF after CABG and were included in this study. Their median age was 71 (IQR, 66-76) years. The median follow-up was 7.1 (IQR, 2.9-9.0) years, and most patients (81.6%) were men. Early AF recurrence occurred in 6.7% of patients. Event rates (95% CIs) per 100 patient-years with vs without early AF recurrence were 2.21 (1.49-3.24) vs 2.03 (1.83-2.25) for all-cause mortality, 3.94 (2.92-5.28) vs 2.79 (2.56-3.05) for heart failure hospitalization, and 3.97 (2.95-5.30) vs 2.74 (2.51-2.99) for major bleeding. No association between early AF recurrence and all-cause mortality was observed (adjusted hazard ratio [AHR], 1.17 [95% CI, 0.80-1.74]; P = .41). In exploratory analyses, there was an association with heart failure hospitalization (AHR, 1.80 [95% CI, 1.32-2.45]; P = .001) and major bleeding (AHR, 1.92 [1.42-2.61]; P < .001). Conclusions and Relevance: In this cohort study of early AF recurrence after POAF in patients who underwent CABG, no association was found between early AF recurrence and all-cause mortality. Exploratory analyses showed associations between AF recurrence and heart failure hospitalization, oral anticoagulation, and major bleeding.

[The Long Outcome of the Left Atrial Appendage Preserving Maze Procedure].

We retrospectively study the outcome of left atrial appendage (LAA) preserving maze procedure, focus on thrombus formation in left atrium( LA), postoperative stroke, and LA function. PATIENTS AND METHODS: We studied 131 patients (mean age, 68.2y;77 men and 54 women) who underwent maze procedure for atrial fibrillation( Af) between 2008 and 2020. Full maze was performed for 116 patients with long-standing persistent Af or persistent Af. Pulmonary vein isolation alone was performed for 15 patients with paroxysmal Af. The mean follow-up period was 2.9( 10.1-0.4) years. RESULTS: In perioperative results, there were no death, cerebral infarction, and reoperation in this series. At discharge, 1 year, 3 years, 5 years, and 10 years after the surgery, sinus rhythm was maintained in 92%, 87%, 83%, 77%. Pacemaker was implanted in 8( early 3, late 5) patients. Despite adequate anticoagulant therapy, one patient developed cerebral infarction a month postoperatively. In other patients, there was no cerebral infarction in short-term nor long-term. CONCLUSIONS: The LAA preserving maze procedure was not a risk factor of cerebral infarction under appropriate medication. However, close follow-up is essential.

Biomarkers of diabetes: role in the pathogenesis of atrial fibrillation.

The prevalence of both atrial fibrillation (AF) and diabetes is increasing day by day and commonly co-exist with a longer duration of diabetes and poor control, putting the individual at higher risk of AF. This review article presented some traditional and novel biomarkers related to AF in patients with diabetes mellitus. The literature review employed several databases, including Google Scholar, PubMed, and Science Direct. The investigation was finished on October 30, 2023. Many terms are utilized, including "AF", "Biomarkers", "Diabetes Mellitus", and "Pathogenesis". There are numerous biomarkers of diabetes, but this review article reports only leptin, adiponectin, glycated hemoglobin, ceramide, ferritin, fibrinogen, hematological indices, interleukin-18, thrombospondin 1, acylcarnitine, plasminogen activator inhibitor-1 and triglycerides and high-density lipoprotein cholesterol, since those biomarkers play a significant role in the pathogenesis of AF. However, no data was found, including fructosamine, glycated albumin, 1,5 anhydroglucitol, fetuin-A, α-hydroxybutyrate, mannose-binding lectin serine peptidase, transferrin, IL-1 receptor antagonist in AF. Understanding the interplay between diabetes and AF through the measurement of relevant biomarkers can contribute to better risk assessment, early detection, and the development of targeted therapeutic strategies for individuals at risk or already affected by these conditions.

Recurrence of new-onset post-operative AF after cardiac surgery: detected by implantable loop recorders: A systematic review and Meta-analysis.

BACKGROUND: Atrial fibrillation (AF) is one of the most common complications after cardiac surgery. New-onset post-operative AF may signal an elevated risk of AF and associated outcomes in long-term follow-up. We aimed to estimate the rate of AF recurrence as detected by an implantable loop recorder (ILR) in patients experiencing post-operative AF within 30 days after cardiac surgery. METHODS: We searched MEDLINE, Embase and Cochrane CENTRAL to April 2023 for studies of adults who did not have known AF, experienced new-onset AF within 30 days of cardiac surgery and received an ILR. We pooled individual participant data on timing of AF recurrence using a random-effects model with a frailty model applied to a Cox proportional hazard analysis. RESULTS: From 8671 citations, 8 single-centre prospective cohort studies met eligibility criteria. Data were available from 185 participants in 7 studies, with a median follow-up of 1.7 (IQR: 1.3-2.8) years. All included studies were at a low risk of bias. Pooled AF recurrence rates following 30 post-operative days were 17.8% (95% CI 11.9%-23.2%) at 3 months, 24.4% (17.7%-30.6%) at 6 months, 30.1% (22.8%-36.7%) at 12 months and 35.3% (27.6%-42.2%) at 18 months. CONCLUSIONS: In patients who experience new-onset post-operative AF after cardiac surgery, AF recurrence lasting at least 30 s occurs in approximately 1 in 3 in the first year after surgery. The optimal frequency and modality to use for monitoring for AF recurrence in this population remain uncertain.

Does iodine fortification affect the risk of atrial fibrillation in incident hyperthyroidism? A national register-based cohort.

OBJECTIVE: Iodine fortification (IF) induces an initial increase followed by a decrease in the incidence of hyperthyroidism in the general population. Within the population of hyperthyroid patients, the sex-, age- and subtype distribution changes after IF. The risk of atrial fibrillation (AF) in hyperthyroid patients may be influenced by these factors. Therefore, we aimed to examine how the association between incident hyperthyroidism and AF was affected by IF increasing the population iodine intake from moderate-mild iodine deficiency to low adequacy. DESIGN, PATIENTS AND MEASUREMENTS: Incident hyperthyroid patients were included at the date of first inpatient or outpatient diagnosis, and AF diagnoses within 3 months before to 6 months after the index date were identified in Danish nationwide registers, 1997-2018. The relative risk (RR) of AF each calendar year (reference: 1997; IF introduced: 2000) was analyzed in Poisson regression models adjusted for age, sex, educational level, geographic region, and comorbidities. RESULTS: Overall, in 62,201 patients with incident hyperthyroidism 7.9% were diagnosed with AF. There was a minor nonsignificantly increased risk of AF during the first years after IF followed by a gradual decrease to RR 0.76 (0.62-0.94) in 2017. There were no statistically significant differences in the development in the risk of AF by sex, age group, or geographic region. CONCLUSIONS: Results indicate that IF may reduce the risk of concomitant AF in hyperthyroid patients. If these results are confirmed, IF may not only reduce the population incidence of hyperthyroidism but also reduce the burden of morbidity in the remaining hyperthyroid patients.

ROS in diabetic atria regulate SK2 degradation by Atrogin-1 through the NF-κB signaling pathway.

One of the independent risk factors for atrial fibrillation is diabetes mellitus (DM); however, the underlying mechanisms causing atrial fibrillation in DM are unknown. The underlying mechanism of Atrogin-1-mediated SK2 degradation and associated signaling pathways are unclear. The aim of this study was to elucidate the relationship among reactive oxygen species (ROS), the NF-κB signaling pathway, and Atrogin-1 protein expression in the atrial myocardia of DM mice. We found that SK2 expression was downregulated comitant with increased ROS generation and enhanced NF-κB signaling activation in the atrial cardiomyocytes of DM mice. These observations were mimicked by exogenously applicating H2O2 and by high glucose culture conditions in HL-1 cells. Inhibition of ROS production by diphenyleneiodonium chloride or silencing of NF-κB by siRNA decreased the protein expression of NF-κB and Atrogin-1 and increased that of SK2 in HL-1 cells with high glucose culture. Moreover, chromatin immunoprecipitation assay demonstrated that NF-κB/p65 directly binds to the promoter of the FBXO32 gene (encoding Atrogin-1), regulating the FBXO32 transcription. Finally, we evaluated the therapeutic effects of curcumin, known as a NF-κB inhibitor, on Atrogin-1 and SK2 expression in DM mice and confirmed that oral administration of curcumin for 4 weeks significantly suppressed Atrogin-1 expression and protected SK2 expression against hyperglycemia. In summary, the results from this study indicated that the ROS/NF-κB signaling pathway participates in Atrogin-1-mediated SK2 regulation in the atria of streptozotocin-induced DM mice.

Factors affecting duration of stay in the intensive care unit after coronary artery bypass surgery and its impact on in-hospital mortality: a retrospective study.

BACKGROUND: Different risk factors affect the intensive care unit (ICU) stay after cardiac surgery. This study aimed to evaluate these risk factors. PATIENTS AND METHODS: A retrospective analysis was conducted on clinical, operative, and outcome data from 1070 patients (mean age: 59 ± 9.8 years) who underwent isolated coronary bypass grafting CABG surgery with cardiopulmonary bypass. The outcome variable was prolonged length of stay LOS in the CICU stay (> 3 nights after CABG). RESULTS: Univariate predictors of prolonged ICU stays included a left atrial diameter of > 4 cm (P < 0.001),chronic obstructive airway disease COPD (P = 0.005), hypertension (P = 0.006), diabetes mellitus (P = 0.009), having coronary stents (P = 0.006), B-blockers use before surgery (either because the surgery was done on urgent or emergency basis or the patients have contraindication to B-blockers use) (P = 0.005), receiving blood transfusion during surgery (P = 0.001), post-operative acute kidney injury (AKI) (P < 0.001), prolonged inotropic support of > 12 h (P < 0.001), and ventilation support of > 12 h (P < 0.001), post-operative sepsis or pneumonia (P < 0.001), post-operative stroke/TIA (P = 0.001), sternal wound infection (P = 0.002), and postoperative atrial fibrillation POAF (P < 0.001). Multivariate regression revealed that patients with anleft atrial LA diameter of > 4 cm (AOR 2.531, P = 0.003), patients who did not take B-blockers before surgery (AOR 1.1 P = 0.011), patients on ventilation support > 12 h (AOR 3.931, P = < 0.001), patients who developed pneumonia (AOR 20.363, P = < 0.001), and patients who developed post-operative atrial fibrillation (AOR 30.683, P = < 0.001) were more likely to stay in the ICU for > 3 nights after CABG. CONCLUSION: Our results showed that LA diameter > 4 cm, patients who did not take beta-blockers before surgery, on ventilation support > 12 h, developed pneumonia post-operatively, and developed POAF were more likely to have stays lasting > 3 nights. Efforts should be directed toward reducing these postoperative complications to shorten the duration of CICU stay, thereby reducing costs and improving bed availability.