INTRODUCTION: Obesity and atrial fibrillation (AF) pose a significant burden on healthcare systems worldwide. Reduction of body weight has been documented to reduce the risk of AF. Little is known about the effect of different weight-reducing interventions including bariatric surgery in obese individuals on the risk of arrhythmia recurrence following catheter ablation (CA) for AF, and about the pathophysiological mechanisms linking these two conditions. METHODS: The Effect of complex weigHt-reducing interventiOns on rhythm control in oBese subjects wITh Atrial Fibrillation (HOBIT-AF) is a single-blinded, parallel-group randomised controlled trial with 18-month follow-up to assess the effect of complex weight-reducing interventions supported by the use of smart technologies and bariatric surgery on the arrhythmia burden in obese individuals following CA for AF. One hundred and sixty individuals (age 18-70 years, body mass index ≥ 30 kg/m2) will be randomised in a 1:1 fashion to undergo a structured weight reduction programme and sleeve gastrectomy (when indicated and preferred by the patient) aiming to achieve greater than 10% weight reduction from baseline (intervention group) or standard post-ablation medical care (control group). Two-week continuous ECG monitoring will be used 3 and 18 months after CA to assess the arrhythmia burden. Other investigations will include transthoracic echocardiography with quantification of epicardial adipose tissue, and markers of low-grade inflammation and circulating adipokines. PLANNED OUTCOMES: The main objective is to assess the effect of complex weight-reducing interventions on the arrhythmia burden and quality of life. Subgroup analyses to identify patient subgroups preferentially benefiting from weight loss related to a decrease in arrhythmia burden will be performed. Exploratory objectives will include investigation of potential mechanisms linking weight reduction with amelioration of arrhythmia burden such as changes in markers of low-grade inflammation, circulating adipokines, cytokines, monocytes or reduction of epicardial adipose tissue volume. TRIAL REGISTRATION: NCT04560387.

• Keywords
• Atrial fibrillation, Bariatric surgery, Low-grade inflammation, Obesity, Sleeve gastrectomy, Weight reduction,
• MeSH
• Adult MeSH
• Atrial Fibrillation * complications   surgery   MeSH
• Weight Loss MeSH
• Catheter Ablation * MeSH
• Quality of Life MeSH
• Middle Aged MeSH
• Humans MeSH
• Adolescent MeSH
• Young Adult MeSH
• Obesity complications   surgery   MeSH
• Randomized Controlled Trials as Topic MeSH
• Recurrence MeSH
• Aged MeSH
• Treatment Outcome MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Adolescent MeSH
• Young Adult MeSH
• Aged MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Clinical Trial Protocol MeSH

Immunocompetent cells including lymphocytes play a key role in the development of adipose tissue inflammation and obesity-related cardiovascular complications. The aim of the study was to explore the relationship between epicardial adipose tissue lymphocytes and coronary artery disease (CAD). To this end, we studied the content and phenotype of lymphocytes in peripheral blood, subcutaneous adipose tissue (SAT), and epicardial adipose tissue (EAT) in subjects with and without CAD undergoing elective cardiac surgery. Eleven subjects without CAD (non-CAD group) and 22 age-, BMI-, and HbA1C-matched individuals with CAD were included into the study. Blood, SAT, and EAT samples were obtained at the beginning of surgery. Lymphocyte populations were quantified as % of CD45+ cells using flow cytometry. Subjects with CAD had a higher total lymphocyte amount in EAT compared with SAT (32.24 ± 7.45 vs. 11.22 ± 1.34%, p = 0.025) with a similar trend observed in non-CAD subjects (29.68 ± 7.61 vs. 10.13 ± 2.01%, p = 0.067). T (CD3+) cells were increased (75.33 ± 2.18 vs. 65.24 ± 4.49%, p = 0.032) and CD3- cells decreased (21.17 ± 2.26 vs. 31.64 ± 4.40%, p = 0.028) in EAT of CAD relative to the non-CAD group. In both groups, EAT showed an elevated percentage of B cells (5.22 ± 2.43 vs. 0.96 ± 0.21%, p = 0.039 for CAD and 12.49 ± 5.83 vs. 1.16 ± 0.19%, p = 0.016 for non-CAD) and reduced natural killer (NK) cells (5.96 ± 1.32 vs. 13.22 ± 2.10%, p = 0.012 for CAD and 5.32 ± 1.97 vs. 13.81 ± 2.72%, p = 0.022 for non-CAD) relative to SAT. In conclusion, epicardial adipose tissue in subjects with CAD shows an increased amount of T lymphocytes relative to non-CAD individuals as well as a higher number of total and B lymphocytes and reduced NK cells as compared with corresponding SAT. These changes could contribute to the development of local inflammation and coronary atherosclerosis.

• MeSH
• B-Lymphocytes MeSH
• Immunohistochemistry MeSH
• Real-Time Polymerase Chain Reaction MeSH
• Middle Aged MeSH
• Humans MeSH
• Coronary Artery Disease blood   immunology   metabolism   MeSH
• Pericardium immunology   metabolism   MeSH
• Subcutaneous Fat immunology   metabolism   MeSH
• Flow Cytometry MeSH
• Aged MeSH
• T-Lymphocytes immunology   metabolism   MeSH
• Adipose Tissue immunology   metabolism   MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH

• Publication type
• Editorial MeSH