Pericardial fat is strongly associated with atrial fibrillation after coronary artery bypass graft surgery†

Influence of epicardial adipose tissue inflammation and adipocyte size on postoperative atrial fibrillation in patients after cardiovascular surgery

Epicardial adipose tissue (EAT) is an active endocrine organ that is closely associated with occurrence of atrial fibrillation (AF). However, the role of EAT in the development of postoperative AF (POAF) remains unclear. We aimed to investigate the association between EAT profile and POAF occurrence in patients who underwent cardiovascular surgery. We obtained EAT samples from 53 patients to evaluate gene expression, histological changes, mitochondrial oxidative phosphorylation (OXPHOS) capacity in the EAT, and protein secretion in EAT-conditioned medium. EAT volume was measured using computed tomography scan. Eighteen patients (34%) experienced POAF within 7 days after surgery. Although no significant difference was observed in EAT profile between patients with and without POAF, logistic regression analysis identified that the mRNA expression levels of tumor necrosis factor-alpha (TNF-α) were positively correlated and adipocyte size in the EAT was inversely correlated with onset of POAF, respectively. Mitochondrial OXPHOS capacity in the EAT was not associated with POAF occurrence; however, it showed an inverse correlation with adipocyte size and a positive correlation with adiponectin secretion. In conclusion, changes in the secretory profile and adipocyte morphology of the EAT, which represent qualitative aspects of the adipose tissue, were present before the onset of AF.

Injectable ice slurry for reducing pericardial adipose tissue

OBJECTIVES

Excess pericardial adipose tissue (PAT) is associated with a higher risk of cardiovascular diseases. Currently, available methods for reducing PAT volume include weight loss through diet and exercise, weight loss with medications, and bariatric surgery. However, these methods are all limited by low patient compliance to maintain the results. We have developed an injectable ice slurry that could selectively target and reduce subcutaneous adipose tissue volume. The aim of this study was to investigate the feasibility and safety of using injectable slurry to selectively reduce PAT volume in a preclinical large animal model.

METHODS

PAT in Yucatan swine was injected with slurry or room temperature control solution. All animals were imaged with baseline chest computed tomography (CT) before slurry injection and at 2 months after injection to quantify PAT volume. Specimens from injected and noninjected PAT were harvested for histology.

RESULTS

Slurry treatment of PAT was well tolerated in all animals. Slurry-induced selective cryolipolysis in treated PAT. CT imaging showed decrease in PAT volume in treated area at 8 weeks posttreatment compared to baseline, that was significantly different from control solution treated group (median [range]: -29.66 [-35.07 to -27.92]% vs. -1.50 [-11.69 to 8.69]% in control animals respectively, p < 0.05).

CONCLUSIONS

This study demonstrated that slurry injection into PAT is feasible in a large animal model. Slurry injection was safe and effective in inducing selective cryolipolysis in PAT and reducing PAT volume. Slurry reduction of PAT could potentially serve as a novel treatment for cardiovascular diseases.

Atrial Fibrillation Occurring During Acute Hospitalization: A Scientific Statement From the American Heart Association

Acute atrial fibrillation is defined as atrial fibrillation detected in the setting of acute care or acute illness; atrial fibrillation may be detected or managed for the first time during acute hospitalization for another condition. Atrial fibrillation after cardiothoracic surgery is a distinct type of acute atrial fibrillation. Acute atrial fibrillation is associated with high risk of long-term atrial fibrillation recurrence, warranting clinical attention during acute hospitalization and over long-term follow-up. A framework of substrates and triggers can be useful for evaluating and managing acute atrial fibrillation. Acute management requires a multipronged approach with interdisciplinary care collaboration, tailoring treatments to the patient's underlying substrate and acute condition. Key components of acute management include identification and treatment of triggers, selection and implementation of rate/rhythm control, and management of anticoagulation. Acute rate or rhythm control strategy should be individualized with consideration of the patient's capacity to tolerate rapid rates or atrioventricular dyssynchrony, and the patient's ability to tolerate the risk of the therapeutic strategy. Given the high risks of atrial fibrillation recurrence in patients with acute atrial fibrillation, clinical follow-up and heart rhythm monitoring are warranted. Long-term management is guided by patient substrate, with implications for intensity of heart rhythm monitoring, anticoagulation, and considerations for rhythm management strategies. Overall management of acute atrial fibrillation addresses substrates and triggers. The 3As of acute management are acute triggers, atrial fibrillation rate/rhythm management, and anticoagulation. The 2As and 2Ms of long-term management include monitoring of heart rhythm and modification of lifestyle and risk factors, in addition to considerations for atrial fibrillation rate/rhythm management and anticoagulation. Several gaps in knowledge related to acute atrial fibrillation exist and warrant future research.

Atrial Fibrillation after Coronary Bypass Surgery? Is Epicardial Fat a Risk Factor?

BACKGROUNDS

 Postoperative atrial fibrillation (POAF) is one of the most common complication of cardiac surgery. Epicardial fat tissue may play a role in the development of atrial fibrillation (AF). The aim of this study was to evaluate relationship between epicardial fat volume (EFV) and the appearance of new-onset AF in patients undergoing isolated coronary artery bypass graft (CABG) with normal echocardiographic functions.

METHODS

 Between January 2017 and June 2020, 281 coronary artery disease patients undergone isolated CABG surgery with normal echocardiographic functions were included in the study. Patient characteristics, medical history, and perioperative variables were retrospectively collected. Patients with AF predisposition factors were excluded.

RESULTS

 Sixty-seven patients (23.8%) developed postoperatively AF during hospital stay. In univariate analysis, patients with postoperative AF were older compared with sinus rhythm patients (60.78 ± 9.03 vs. 65.46 ± 9.22, p = 0.001). There are no statistically significant differences between groups and EFV compared (107.78 ± 41.04 vs. 106.66 ± 34.98 p = 0.84). Large left atrial diameter, female patient, cardiopulmonary bypass and longer cross-clamp time showed correlation between POAF without statistical significance.

CONCLUSION

 Aging is the only associated factor with AF in this study. There was no EFV difference between POAF and non-AF groups in patients undergoing isolated CABG with normal echocardiographic functions.

Postoperative atrial fibrillation and atrial epicardial fat: Is there a link?

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Detailed local EAT analysis does not differ between POAF and non-POAF.

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General rather than local effects of EAT play a role in the onset of early POAF.

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The dominance of surgical induced factors may obscure the potential role of EAT.

Background

Atrial Epicardial Adipose Tissue (EAT) is presumably involved in the pathogenesis of atrial fibrillation (AF). The transient nature of postoperative AF (POAF) suggests that surgery-induced triggers provoke an unmasking of a pre-existent AF substrate. The aim is to investigate the association between the volume of EAT and the occurrence of POAF. We hypothesise that the likelihood of developing POAF is higher in patients with high compared to low left atrial (LA) EAT volumes.

Methods

Quantification of LA EAT based on the Hounsfield Units using custom made software was performed on pre-operative coronary computed tomography angiography scans of patients who underwent cardiac surgery between 2009 and 2019. Patients with mitral valve disease were excluded.

Results

A total of 83 patients were included in this study (CABG = 34, aortic valve = 33, aorta ascendens n = 7, combination n = 9), of which 43 patients developed POAF. The EAT percentage in the LA wall nor indexed EAT volumes differed between patients with POAF and with sinus rhythm (all P > 0.05). In multivariable analysis, age and LA volume index (LAVI) were the only independent predictors for early POAF (OR: 1.076 and 1.056, respectively).

Conclusions

As expected, advanced age and LAVI were independent predictors of POAF. However, the amount of local EAT was not associated with the occurrence of AF after cardiac surgery. This suggests that the role of EAT in POAF is rather limited, or that the association of EAT in the early phase of POAF is obscured by the dominance of surgical-induced triggers.

The adiponectin signalling pathway - A therapeutic target for the cardiac complications of type 2 diabetes?

Diabetes is associated with an increased risk of heart failure (HF). This is commonly termed diabetic cardiomyopathy and is often characterised by increased cardiac fibrosis, pathological hypertrophy, increased oxidative and endoplasmic reticulum stress as well as diastolic dysfunction. Adiponectin is a cardioprotective adipokine that is downregulated in settings of type 2 diabetes (T2D) and obesity. Furthermore, both adiponectin receptors (AdipoR1 and R2) are also downregulated in these settings which further results in impaired cardiac adiponectin signalling and reduced cardioprotection. In many cardiac pathologies, adiponectin signalling has been shown to protect against cardiac remodelling and lipotoxicity, however its cardioprotective actions in T2D-induced cardiomyopathy remain unresolved. Diabetic cardiomyopathy has historically lacked effective treatment options. In this review, we summarise the current evidence for links between the suppressed adiponectin signalling pathway and cardiac dysfunction, in diabetes. We describe adiponectin receptor-mediated signalling pathways that are normally associated with cardioprotection, as well as current and potential future therapeutic approaches that could target this pathway as possible interventions for diabetic cardiomyopathy.

Inflammation and adiposity: new frontiers in atrial fibrillation

The aetiology of atrial fibrillation (AF) remains poorly understood, despite its growing prevalence and associated morbidity, mortality, and healthcare costs. Obesity is implicated in myriad different disease processes and is now recognized a major risk factor in the pathogenesis of AF. Moreover, the role of distinct adipose tissue depots is a matter of intense scientific interest with the depot directly surrounding the heart—epicardial adipose tissue (EAT) appearing to have the greatest correlation with AF presence and severity. Similarly, inflammation is implicated in the pathophysiology of AF with EAT thought to act as a local depot of inflammatory mediators. These can easily diffuse into atrial tissue with the potential to alter its structural and electrical properties. Various meta-analyses have indicated that EAT size is an independent risk factor for AF with adipose tissue expansion being inevitably associated with a local inflammatory process. Here, we first briefly review adipose tissue anatomy and physiology then move on to the epidemiological data correlating EAT, inflammation, and AF. We focus particularly on discussing the mechanistic basis of how EAT inflammation may precipitate and maintain AF. Finally, we review how EAT can be utilized to help in the clinical management of AF patients and discuss future avenues for research.

Echocardiographically Measured Epicardial Fat Predicts New-onset Atrial Fibrillation after Cardiac Surgery

Objective

The current study aims to investigate the role of echocardiographically measured epicardial adipose tissue (EAT) thickness in the prediction of new-onset atrial fibrillation (AF) following coronary artery bypass grafting (CABG) surgery.

Methods

One hundred and twenty-four patients scheduled to undergo isolated on-pump CABG due to coronary artery disease were enrolled to the current study. Patient characteristics, medical history and perioperative variables were prospectively collected. EAT thickness was measured using transthoracic echocardiography (TTE). Any documented episode of new-onset postoperative AF (POAF) until discharge was defined as the study endpoint. Fortyfour participants with POAF served as AF group and 80 patients without AF served as Non-AF group.

Results

Two groups were similar in terms of baseline echocardiographic and laboratory findings. In laboratory findings, the groups were similar in terms of the studied parameters, except N-terminal pro-brain natriuretic peptide (NT Pro-BNP), which was higher in AF group than in Non-AF group (P=0.035). The number of left internal mammary artery (LIMA) grafts was not different in both groups. AF group had higher cross-clamp (CC) and cardiopulmonary bypass (CPB) times than Non-AF group (P=0.01 and P<0.001). In multivariate logistic regression analysis, EAT was found an independent predictor for the development of POAF (OR 4.47, 95% CI 3.07-5.87, P=0.001).

Conclusion

We have shown that EAT thickness is associated with increased risk of AF development and can be used as a prognostic marker for this purpose.

Accumulation of Pericardial Fat Is Associated With Alterations in Heart Rate Variability Patterns in Hypercholesterolemic Pigs

BACKGROUND

Heart rate variability (HRV) and pulse rate variability are indices of autonomic cardiac modulation. Increased pericardial fat is associated with worse cardiovascular outcomes. We hypothesized that progressive increases in pericardial fat volume and inflammation prospectively dampen HRV in hypercholesterolemic pigs.

METHODS

WT (wild type) or PCSK9 (proprotein convertase subtilisin-like/kexin type-9) gain-of-function Ossabaw mini-pigs were studied in vivo before and after 3 and 6 months of a normal diet (WT-normal diet, n=4; PCSK9-normal diet, n=6) or high-fat diet (HFD; WT-HFD, n=3; PCSK9-HFD, n=6). The arterial pulse waveform was obtained from an arterial telemetry transmitter to analyze HRV indices, including SD (SD of all pulse-to-pulse intervals over a single 5-minute period), root mean square of successive differences, proportion >50 ms of normal-to-normal R-R intervals, and the calculated ratio of low-to-high frequency distributions (low-frequency power/high-frequency power). Pericardial fat volumes were evaluated using multidetector computed tomography and its inflammation by gene expression of TNF (tumor necrosis factor)-α. Plasma lipid panel and norepinephrine level were also measured.

RESULTS

At diet completion, hypercholesterolemic PCSK9-HFD had significantly (P<0.05 versus baseline) depressed HRV (SD of all pulse-to-pulse intervals over a single 5-minute period, root mean square of successive differences, proportion >50 ms, high-frequency power, low-frequency power), and both HFD groups had higher sympathovagal balance (SD of all pulse-to-pulse intervals over a single 5-minute period/root mean square of successive differences, low-frequency power/high-frequency power) compared with normal diet. Pericardial fat volumes and LDL (low-density lipoprotein) cholesterol concentrations correlated inversely with HRV and directly with sympathovagal balance, while sympathovagal balance correlated directly with plasma norepinephrine. Pericardial fat TNF-α expression was upregulated in PCSK9-HFD, colocalized with nerve fibers, and correlated inversely with root mean square of successive differences and proportion >50 ms.

CONCLUSIONS

Progressive pericardial fat expansion and inflammation are associated with a fall in HRV in Ossabaw mini-pigs, implying aggravated autonomic imbalance. Hence, pericardial fat accumulation is associated with alterations in HRV and the autonomic nervous system. Visual Overview: A visual overview is available for this article.

The concentration of resistin in perivascular adipose tissue after CABG and postoperative atrial fibrillation

BACKGROUND

Postoperative atrial fibrillation occurs in up to 30% of patients after coronary artery bypass graft (CABG) and its cause is unknown. The aim of the study was to evaluate whether concentration of resistin in surrounding coronary artery perivascular adipose tissue (PVAT) is related to postoperative atrial fibrillation occurrence.

METHODS

A total number of 46 patients (35 male, 11 female; median age 66.5) were qualified for elective CABG. Medical history, laboratory test results and echocardiographic parameters were noted. Patients were monitored up to 3 days after CABG and then were divided into groups with and without postoperative atrial fibrillation occurrence. Fragments of PVAT were collected intra-operatively: near the left anterior descending artery and main left coronary artery. The concentration of resistin was determined by Human Resistin Quantikine ELISA Kit and expressed as ng/g. A multivariate stepwise logistic regression analysis was performed to find variables related to postoperative atrial fibrillation occurrence.

RESULTS

Postoperative atrial fibrillation occurred in 14 (30.4%) patients. The patients with and without postoperative atrial fibrillation were similar in age, gender, epicardial adipose tissue thickness and laboratory parameters. The concentration of resistin in PVAT near the left main coronary artery was significantly higher in patients with postoperative atrial fibrillation than in those without the complication (P = 0.03). In the multivariate stepwise logistic regression analysis the concentration of resistin above cut-off point 54 ng/g in PVAT near left main coronary artery was independently related to postoperative atrial fibrillation occurrence (OR: 7.7; 95% CI:1.4-42.2 p = 0.02).

CONCLUSIONS

The higher concentrations of resistin in PVAT near the left main coronary artery which is located close to the left atrium are associated with postoperative atrial fibrillation.

Effects of high-dose vitamin D supplementation on the occurrence of post-operative atrial fibrillation after coronary artery bypass grafting: randomized controlled trial

OBJECTIVE

This study aimed to investigate the preventive effects of a high-dose vitamin D administered preoperatively on the post-operative atrial fibrillation (POAF) occurrence in patients with insufficient or deficient serum vitamin D levels who underwent coronary artery bypass grafting (CABG) surgery.

METHODS

The study was a randomized controlled, blinded and parallel-arm trial conducted on 116 who had vitamin D deficiency or insufficiency during the pre-operative evaluation were included in the study conducted between January 2018 and January 2019. Patients were divided into those who received oral vitamin D (treatment group; n = 58) and those who did not (control group; n = 58) 48 h before CABG surgery. In the treatment group, patients with vitamin D deficiency were administered 300.000 IU vitamin D orally and those with vitamin D insufficiency 150.000 IU 48 h preoperatively. Patients were followed up during hospitalisation process with respect to POAF.

RESULTS

Both groups showed no significant differences with regard to age, gender, body mass index, creatine level, left atrial diameter, pre-operative drug use, calcium level, ejection fraction, diabetes mellitus and hypertension. The ratio of POAF occurrence found in the treatment and control groups were 12.07% and 27.59%, respectively. Vitamin D treatment was found to reduce the risk of POAF development by 0.24 times (p = 0.034).

CONCLUSION

In this study with sufficient sample size, preoperative short-term high-dose vitamin D supplementation was found to be significantly preventive to the occurrence of POAF in patients with vitamin D insufficiency and deficiency who underwent CABG surgery.

Does Epicardial Adipose Tissue Influence Postoperative Atrial Fibrillation?

Purpose: Epicardial adipose tissue (EAT) is associated with atrial fibrillation. We investigated the effect of EAT on postoperative atrial fibrillation (POAF) after cardiac surgery.

Methods: In all, 77 patients underwent scheduled cardiac surgery. Before the operation, we measured total epicardial adipose tissue (Total EAT) and left atrial (LA) EAT by three-dimensional computed tomography (CT). During surgery, we obtained samples of the right atrial appendage, aortic fat, and epicardial fat. The primary endpoint was occurrence of POAF within 1 week after surgery.

Results: POAF occurred in 21 patients (27%). Assessment of preoperative characteristics revealed significant differences of age and the use of aldosterone blockers and loop diuretics between the patients with and without POAF. In univariate analysis, the LA EAT/Total EAT ratio, age, use of aldosterone blockers and loop diuretics, P wave duration, cardioplegia volume, and central venous pressure (CVP) were all higher in POAF group. However, logistic regression analysis with propensity score matching found no significant differences of these factors although the LA EAT/Total EAT ratio was higher in POAF group.

Conclusion: The use of loop diuretics showed the strongest association with POAF. Logistic regression analysis suggested that a high LA EAT/Total EAT ratio had the second strongest association with POAF.

Epicardial Adipose Tissue and Cardiovascular Disease

PURPOSE OF REVIEW

Epicardial adipose tissue has been associated with the development/progression of cardiovascular disease. We appraise the strength of the association between epicardial adipose tissue and development/progression of cardiovascular diseases like coronary artery disease, atrial fibrillation, and heart failure with preserved ejection fraction.

RECENT FINDINGS

Cross-sectional clinical and translational correlative studies have established an association between epicardial adipose tissue and progression of coronary artery disease. Recent studies question this association and underline the need for longitudinal studies. Epicardial adipose tissue also plays a definite role in the pathobiology of atrial fibrillation and its recurrence after ablation. In contrast to an early paradigm, epicardial adipose tissue does not appear to play a key role in the pathogenesis of heart failure with preserved ejection fraction in obese patients. The association of epicardial adipose tissue with atrial fibrillation is robust. In contrast, the association of epicardial adipose tissue with coronary artery disease and heart failure with preserved ejection fraction is tenuous. Additional research, including longitudinal studies, is needed to confirm or refute these proposed associations.

Epicardial adipose tissue and atrial fibrillation: pathophysiological mechanisms, clinical implications, and potential therapies

BACKGROUND

Atrial fibrillation (AF) is the most common arrhythmia in clinical practice and is associated with increased cardiovascular morbidity and mortality. Epicardial adipose tissue (EAT) serves as a biologically active organ with important endocrine and inflammatory function. Review An accumulating body of evidence suggests that EAT is associated with the initiation, perpetuation, and recurrence of AF, but the precise role of EAT in AF pathogenesis is not completely elucidated. Pathophysiological mechanisms involve adipocyte infiltration, profibrotic and pro-inflammatory paracrine effects, oxidative stress, neural mechanisms, and genetic factors.

CONCLUSIONS

Notably, EAT accumulation seems to be associated with stroke and adverse cardiovascular outcomes in AF. Weight loss, specific medications and ablation of ganglionated plexi (GP) seem to be potential therapies in this setting.

Human Epicardial Adipose Tissue Activin A Expression Predicts Occurrence of Postoperative Atrial Fibrillation in Patients Receiving Cardiac Surgery

BACKGROUND

Activin A secreted by epicardial adipose tissue (EAT) plays a major role in the progress of atrial fibrosis. However, the potential of Activin A in predicting the occurrence of postoperative atrial fibrillation (POAF) has yet to be elucidated. We aimed to investigate the predicable value of Activin A expression in EAT on POAF.

METHODS

A total of 89 patients receiving cardiac surgery without atrial fibrillation (AF) history were enrolled in this study, including 49 patients with valvular heart disease (VHD) and 40 patients with non-valvular heart disease (NVHD). Activin A expression in EAT was determined by quantitative polymerase chain reaction (qPCR), while the thickness of EAT (EATT) was estimated by echocardiography. New onset POAF before discharge was documented.

RESULTS

Eventually 32 patients (36.0%) developed POAF, including 20 patients with VHD (40.8%) and 12 patients with NVHD (30.0%). Activin A expression was higher in POAF than sinus rhythm (SR) patients, whether for VHD or NVHD group (All p<0.001). In general, Activin A expression predicted the occurrence of POAF with a sensitivity of 65.6% and specificity of 91.2% (AUC: 0.795; 95%CI: 0.693-0.897, p<0.001). Subgroup analysis showed that EATT was not significant for the VHD group in predicting POAF (p=0.07), while Activin A expression demonstrated a sensitivity of 60.0% and specificity of 89.7% (AUC: 0.745; 95%CI: 0.601-0.889, p<0.001). Multivariate regression analysis showed that Activin A expression in EAT was an independent risk factor for POAF (OR: OR=1.067, 95%CI:1.002-1.136, p=0.042).

CONCLUSIONS

Activin A expression in EAT is an independent risk factor for POAF, which can be used for prediction of POAF, especially for patients with VHD.

Epicardial fat and atrial fibrillation: current evidence, potential mechanisms, clinical implications, and future directions

Obesity is increasingly recognized as a major modifiable determinant of atrial fibrillation (AF). Although body mass index and other clinical measures are useful indications of general adiposity, much recent interest has focused on epicardial fat, a distinct adipose tissue depot that can be readily assessed using non-invasive imaging techniques. A growing body of data from epidemiological and clinical studies has demonstrated that epicardial fat is consistently associated with the presence, severity, and recurrence of AF across a range of clinical settings. Evidence from basic science and translational studies has also suggested that arrhythmogenic mechanisms may involve adipocyte infiltration, pro-fibrotic, and pro-inflammatory paracrine effects, oxidative stress, and other pathways. Despite these advances, however, significant uncertainty exists and many questions remain unanswered. In this article, we review our present understanding of epicardial fat, including its classification and quantification, existing evidence implicating its role in AF, potential mechanisms, implications for clinicians, and future directions for research.

Incidence and predictors of atrial fibrillation after coronary artery bypass surgery: detection by event loop recorder monitoring from a contemporary multicentre cohort

Background Atrial fibrillation (AF) is a frequent complication after cardiac surgery. We explored the incidence and predictors of post-operative AF at 30-day follow-up in an unselected multi-centre cohort of patients undergoing elective coronary artery bypass grafting (CABG) in contemporary practice. Methods and results We enrolled 740 consecutive patients scheduled for elective CABG with or without valve surgery. Cardiac rhythm was continuously monitored for 15 days after surgery by an ambulatory event loop recorder. Clinical follow-up for the occurrence of arrhythmias was performed for the next 15 days by office visits. The primary end point was the incidence of AF at 30-day follow-up. Mean age was 56.5 ± 8.9 years; 69.5% were males; 80% had diabetes. All patients completed 30-day follow-up. At the end of 30 days, AF occurred in 77 patients (10.4%). Most episodes (47 out of 77 episodes, 61%) of AF occurred during post-operative day 2. Episodes of AF were very rare after the first 5 post-operative days (3 out of 77 episodes, 3.9%). Multivariable regression analysis identified the following independent predictors of AF at 30-day follow-up: the lack of beta blocker use (hazard ratio 0.37, 95% confidence interval 0.21-0.64, P < 0.001), and the preoperative left atrial volume index (hazard Ratio 2.21, 95% confidence interval 1.79-2.74, P < 0.001). Conclusions In patients undergoing elective CABG, the incidence of post-operative AF at 30-day follow-up is rather low; the lack of beta blocker use in the perioperative period, and the preoperative left atrial volume index independently predicted the occurrence of AF at 30 days.

Associations of Epicardial, Abdominal, and Overall Adiposity With Atrial Fibrillation

Background—

Although adiposity is increasingly recognized as a risk factor for atrial fibrillation (AF), the importance of epicardial fat compared with other adipose tissue depots remains uncertain. We sought to characterize and compare the associations of AF with epicardial fat and measures of abdominal and overall adiposity.

Methods and Results—

We conducted a meta-analysis of 63 observational studies including 352 275 individuals, comparing AF risk for 1-SD increases in epicardial fat, waist circumference, waist/hip ratio, and body mass index. A 1-SD higher epicardial fat volume was associated with a 2.6-fold higher odds of AF (odds ratio, 2.61; 95% confidence interval [CI], 1.89–3.60), 2.1-fold higher odds of paroxysmal AF (odds ratio, 2.14; 95% CI, 1.45–3.16) and, 5.4-fold higher odds of persistent AF (odds ratio, 5.43; 95% CI, 3.24–9.12) compared with sinus rhythm. Likewise, a 1-SD higher epicardial fat volume was associated with 2.2-fold higher odds of persistent compared with paroxysmal AF (odds ratio, 2.19; 95% CI, 1.66–2.88). Similar associations existed for postablation, postoperative, and postcardioversion AF. In contrast, associations of abdominal and overall adiposity with AF were less extreme, with relative risks per 1-SD higher values of 1.32 (95% CI, 1.25–1.41) for waist circumference, 1.11 (95% CI, 1.08–1.14) for waist/hip ratio, and 1.22 (95% CI, 1.17–1.27) for body mass index.

Conclusions—

Strong and graded associations were observed between increasing epicardial fat and AF. Moreover, the strength of associations of AF with epicardial fat is greater than for measures of abdominal or overall adiposity. Further studies are needed to assess the mechanisms and clinical relevance of epicardial fat.

Obesity and postoperative atrial fibrillation in patients undergoing cardiac surgery: Systematic review and meta-analysis

INTRODUCTION

Post-operative atrial fibrillation (POAF) is one of the most common complications following cardiac surgery. However, it is unclear whether there is a relationship between obesity and POAF. We thus assessed all available evidence investigating the association between obesity and POAF, also considering any link between POAF and other post-operative conditions such as mortality, stroke, myocardial infarctions and respiratory complications.

METHODS

Five electronic databases were searched and relevant studies were identified. Data was extracted and meta-analyzed from the identified studies.

RESULTS

We found that obese patients had significantly higher odds of POAF when compared with non-obese patients (P=0.006). There was also significant heterogeneity among the identified studies. POAF when compared with no-POAF was associated with an increased risk of stroke (P<0.0001), 30-day mortality (P=0.005) and respiratory complications (P<0.00001). However, we found no significant link between POAF and myocardial infarctions (P=0.79).

CONCLUSIONS

Our findings suggest that obesity is associated with a moderately higher risk of POAF. While POAF is also associated with an increased incidence of stroke, 30-day mortality and respiratory complications, further studies must be conducted before conclusions can be made about the long-term outcomes.

Low Circulating Levels of Growth Differentiation Factor-15 Before Coronary Artery Bypass Surgery May Predict Postoperative Atrial Fibrillation

OBJECTIVES

To assess the role of growth differentiation factor-15 (GDF-15) as a potential new predictor of postoperative atrial fibrillation (POAF) after off-pump (OFP) and on-pump (ONP) coronary artery bypass graft (CABG) surgery.

DESIGN

Prospective, single-center, observational study.

SETTING

University teaching hospital.

PARTICIPANTS

The first 50 patients planned for OFP surgery and the first 50 patients planned for ONP surgery among patients referred for CABG with the following exclusion criteria: age<18 or>80 years, previous atrial fibrillation/flutter, previous treatment with amiodarone, previous cardiac surgery, and emergency surgery.

INTERVENTIONS

Included patients were equipped with long-duration (7 days) Holter-ECG monitoring.

MEASUREMENTS AND MAIN RESULTS

POAF was defined as an AF episode lasting>30 seconds. All patients underwent preoperative echocardiography to assess left ventricular ejection fraction and left atrial diameter. GDF-15 levels were assessed after induction of anesthesia and 12 hours after arrival at the intensive care unit. Among the 100 patients, 34 (34%) developed POAF. In Cox multivariate regression analysis, the EuroSCORE, left atrial diameter>45 mm, and low GDF-15 levels at induction were associated independently with the onset of POAF. In contrast, preoperative NT-proBNP levels did not predict POAF. The use of ONP surgery was not associated with a higher incidence of POAF, even though baseline and follow-up characteristics in ONP and OFP patients were identical.

CONCLUSIONS

In patients with no history of AF, a low plasma level of GDF-15 before CABG surgery was a strong independent predictor of POAF. Moreover, preoperative plasma GDF-15 levels added an incremental predictive value to classic risk factors of POAF.

Computed tomography angiography for prediction of atrial fibrillation after coronary artery bypass grafting: proof of concept

BACKGROUND

Postoperative atrial fibrillation (AF) is a serious complication of coronary artery bypass grafting (CABG). There are scant data on the application of coronary computed tomography angiography (CCTA) for prediction of postoperative AF.

METHODS

A total of 102 patients (77 male, mean age: 64±10 years) with pre-procedural CCTA undergoing isolated CABG were enrolled. Clinical risk factors were collected. Qualitative and quantitative CCTA analysis of the atria, pulmonary veins (PV), and epicardial adipose tissue (EAT) along the left atrium (LA) was performed to determine the predictors for postoperative AF. The primary endpoint was defined as any in-hospital AF requiring treatment.

RESULTS

Postoperative AF occurred in 24% of patients. Patients with AF had higher body mass index (29.7±4.8kg/m(2) vs 27.3±3.9kg/m(2), p=0.013), larger right atrial area (25.4±5.3cm(2) vs 22.3±6.4cm(2), p=0.035), LA systolic volume (114.7±32.8ml vs 96.8±30.4ml, p=0.015), LA EAT volume (5.6±3ml vs 4±2.5ml, p=0.009), and right superior PV ostium area (3.8±1.3cm(2) vs 3±1cm(2), p=0.021) compared to non-AF patients. By multivariable analysis, only LA EAT volume [odds ratio (OR): 1.21, 95% confidence interval (CI): 1.01-1.44, p=0.036] and right superior PV ostium area (OR: 1.63, 95% CI: 1.06-2.50, p=0.026) were independent predictors of AF. The optimal cut-offs for LA EAT volume and right superior PV ostium were >3.4ml and >4.1cm(2), respectively (max. sensitivity: 83%, max. specificity: 86%).

CONCLUSIONS

Increased LA EAT and right superior PV ostial size are independently associated with AF after CABG. CCTA might be used as a noninvasive prediction tool for AF in patients undergoing CABG.

Cardiac adipose tissue and its relationship to diabetes mellitus and cardiovascular disease

Type-2 diabetes mellitus (T2DM) plays a central role in the development of cardiovascular disease (CVD). However, its relationship to epicardial adipose tissue (EAT) and pericardial adipose tissue (PAT) in particular is important in the pathophysiology of coronary artery disease. Owing to its close proximity to the heart and coronary vasculature, EAT exerts a direct metabolic impact by secreting proinflammatory adipokines and free fatty acids, which promote CVD locally. In this review, we have discussed the relationship between T2DM and cardiac fat deposits, particularly EAT and PAT, which together exert a big impact on the cardiovascular health.