The role of obesity in the development of atrial fibrillation: current problem status

Impact Of Obesity On Cardiac Structural And Functional Changes

The urgency of obesity issue is undeniable. Obesity is now considered the most important risk factor of cardiovascular diseases. Numerous studies have demonstrated the negative effect of excessive adipose tissue on structural and functional changes in the heart that lead to development of left ventricular hypertrophy, arrhythmias and conduction abnormalities, as well as progression of diastolic and systolic heart failure. High prevalence of obesity – so high that it can be called a pandemic – greatly contributes to the increased incidence of cardiovascular diseases. Studying the problem of obesity is a priority area of focus for modern medicine. This article describes hormonal, metabolic and hemodynamic features of obesity impact on cardiovascular system and describes pathogenetic mechanisms of cardiovascular pathology development.

The Role of Adipokines in Cardiovascular Pathology

The recent decades saw a steady growth of obesity incidence worldwide. Obesity is an independent risk factor for cardiovascular diseases (CVDs) and type 2 diabetes mellitus and is also associated with a shorter life expectancy. Not only hemodynamic but also hormone metabolic processes, arising from excessive accumulation of adipose tissue in human body, underlie the development of CVDs. Adipose tissue has now been proved to be a hormone-active substrate. Studies of the influence of adipokines will bring us closer to understanding cardiovascular pathogenesis and help personalize prophylactic strategies.

Role of epicardial adipose tissue in the development of atrial fibrillation in hypertensive patients

Obesity is a progressing epidemic, the prevalence of which has doubled over the past 30 years. The distribution of adipose tissue is an important factor in predicting the risk of cardiovascular events. The most significant inflammatory activity is characteristic of epicardial adipose tissue (EAT), the role of which in the development of atrial fibrillation (AF) remains a subject of discussion.

Aim. To study the effect of EAT size on the development of AF in hypertensive (HTN) patients.

Material and methods. The study included 95 patients with HTN aged 38-72 years (mean age, 61,5±1,8 years), including 45 patients with paroxysmal AF (group I) and 50 patients in the comparison group (group II). In order to assess the severity of visceral obesity, all patients underwent a general examination and echocardiography. To determine the EAT volume, cardiac multislice computed tomography was performed.

Results. Echocardiography revealed that the EAT thickness was significantly greater in hypertensive patients with paroxysmal AF than in the comparison group: 11,6±0,8 and 8,6±0,4 mm, respectively (p<0,001). According to cardiac multislice computed tomography, a significant increase in EAT volume was revealed in patients of group I (4,6±0,4 ml) compared with group II (3,5±0,25 ml) (p=0,019). In hypertensive patients with paroxysmal AF, a positive moderate relationship between the EAT volume and left atrial volume was revealed (r=0,7, p=0,022). Multivariate analysis showed that in hypertensive patients, EAT thickness >10 mm and volume >6 ml can serve as integral markers of the onset of paroxysmal AF.

Conclusion. Integral markers of AF in hypertensive patients are an increase in the EAT thickness >10 mm (odds ratio, 4,1; 95% confidence interval, 1,1-5,6) and volume >6 ml (odds ratio 3,7; 95%, confidence interval 1,0-4,2).

Changes in Arterial Wall Stiffness in Patients with Obesity and Paroxysmal Form of Atrial Fibrillation

Aim. To study changes in vascular wall stiffness in patients with obesity and paroxysmal atrial fibrillation (AF) during sinus rhythm retention.

Material and methods. The study included 86 obese patients aged 38 to 72 years. Patients were divided into 2 groups: 42 patients with paroxysmal AF and obesity (Group I) and 44 patients with obesity and without rhythm disturbance (Group II). All patients were evaluated for the main parameters of arterial wall stiffness: the heart-ankle vascular index (CAVI) and the ankle-brachial index (ABI) in the right and left main arteries.

Results. Body mass index (BMI) did not differ significantly between groups. The prevalence of visceral obesity in patients with paroxysmal AF was significantly higher than in patients without heart rhythm disorders. The study of vascular wall rigidity revealed a significant increase in the CAVI index in patients with paroxysmal AF compared with this in patients without cardiac arrhythmia. The average value of the CAVI index was 9.61±1.51 and 7.92±0.18, respectively (p=0.0003). In patients with obesity and paroxysmal AF, correlations were found between waist circumference to hip circumference (WC/HC) ratio and CAVI index (r=0.455, p=0.004); WC/height ratio and CAVI index (r=0.443, p=0.003); between WC and CAVI index (r=0.493, p=0.002). A positive direct relationship was found between CAVI index and the frequency of AF attacks during the year: r=0.782 (p=0.001).

Conclusion. A significant increase in the CAVI index, indicating a change in vascular wall stiffness, was found in patients with obesity and paroxysmal AF when compared with overweight patients without heart rhythm disorders. The increase in the CAVI index was correlated with the increase in WC, the WC/HC ratio, and WC/height ratio. There was a significant direct relationship between the CAVI index and the frequency of arrhythmia attacks in patients with obesity and paroxysmal AF.