Here is the design of a clinical trial:

Official Title: Effect of Complex Weight-reducing Interventions on Rhythm Control in Obese Subjects With Atrial Fibrillation

Included conditions:
- Atrial Fibrillation
- Obesity

Study Armgroups:
- {'label': 'Interventional', 'type': 'EXPERIMENTAL', 'description': 'Physician-lead complex program of weight-reducing interventions including education, diet counselling and regular physical activity aimed at achieving and maintaining a 10% reduction of baseline body weight.\n\nBariatric surgery - sleeve gastrectomy in a subgroup of subjects with BMI \\> 35 kg/m2, i.e. standard indication of bariatric surgery (patients with BMI \\> 35 kg/m2 and a presence of metabolic or other complications).', 'interventionNames': ['Behavioral: Physician-lead complex program of weight-reducing interventions', 'Procedure: Bariatric surgery - sleeve gastrectomy']}
- {'label': 'Conservative', 'type': 'NO_INTERVENTION', 'description': 'Routine treatment of obesity'}

Interventions:
- {'type': 'BEHAVIORAL', 'name': 'Physician-lead complex program of weight-reducing interventions', 'description': 'A structured motivational and goal directed program will be used for weight reduction involving physicians, nutritionists, educators and physiotherapists. Initially, based on the input data provided by the patient an individual nutritional plan will be designed with the aim of reducing caloric intake by 10%. Low-intensity aerobic exercise for 30 min will be prescribed 3-times a week with the aim of increasing the frequency to 5-times a week and participants will be offered the possibility to participate in regular physiotherapist-lead group exercises. Patients will be required to maintain a diet and physical activity diary. Regular reviews will be scheduled every 3-6 months according to the actual weight loss.', 'armGroupLabels': ['Interventional']}
- {'type': 'PROCEDURE', 'name': 'Bariatric surgery - sleeve gastrectomy', 'description': "Bariatric surgery will be performed based on actual medical indication and independently of patient's participation in the study. Sleeve gastrectomy was selected as the currently most frequent restrictive type of bariatric surgery with a proven efficacy on weight reduction, metabolic status and low-grade inflammation", 'armGroupLabels': ['Interventional']}

Primary Outcomes:
- {'measure': 'Atrial fibrillation burden', 'description': 'Atrial fibrillation burden expressed as % of total monitoring time at final visit', 'timeFrame': '18 months'}

Please estimate the sample size based on the assumption: 
80% power, 5% two-sided significance level, 20% dropout rate, statistical analysis using SigmaStat software, results expressed as mean ± SEM, t tests or rank sum tests for two-group comparisons, one-way ANOVA or Kruskal-Wallis test for multiple group comparisons, P value < 0.05 considered significant.
Sample Size Calculation and Statistical Analysis
      Sample size calculation is based on the study by Abed et al. in which weight-reducing lifestyle interventions were associated with a 68.2% (1055Â min) difference of AF burden in comparison to non-interventional controls [12]. Given these data, a sample size of 68 individuals in each group will give 80% power of detecting a difference in AF burden as statistically significant at the 5% two-sided significance level. Assuming a dropout rate of approximately 20%, we plan to enrol 160 (80â+â80) participants in total. Statistical analysis will be performed using SigmaStat software (Systat Software Inc., San Jose, CA, USA). Results will be expressed as meanâÂ±âSEM. We will use t tests or rank sum tests for two-group comparisons and one-way ANOVA or KruskalâWallis test for multiple group comparisons as appropriate according to the normality of data distribution. A P value less than 0.05 will be considered statistically significant.