Effects of a high-fat diet on the electrical properties of porcine atria

The impact of lifestyle factors on atrial fibrillation

Atrial fibrillation (AF), with its significant associated morbidity and mortality contributes to significant healthcare utilisation and expenditure. Given its progressively rising incidence, strategies to limit AF development and progression are urgently needed. Lifestyle modification is a potentially potent but underutilised weapon against the AF epidemic. The purpose of this article is to review the role of lifestyle factors as risk factors for AF, outline potential mechanisms of pathogenesis and examine the available evidence for lifestyle intervention in primary and secondary AF prevention. It will also highlight the need for investment by physicians, researchers, health services and governments in order to facilitate delivery of the comprehensive, multidisciplinary AF care that is required to manage this complex and multifactorial disease.

Metabolic remodelling in atrial fibrillation: manifestations, mechanisms and clinical implications

Atrial fibrillation (AF) is a continually growing health-care burden that often presents together with metabolic disorders, including diabetes mellitus and obesity. Current treatments often fall short of preventing AF and its adverse outcomes. Accumulating evidence suggests that metabolic disturbances can promote the development of AF through structural and electrophysiological remodelling, but the underlying mechanisms that predispose an individual to AF are aetiology-dependent, thus emphasizing the need for tailored therapeutic strategies to treat AF that target an individual's metabolic profile. AF itself can induce changes in glucose, lipid and ketone metabolism, mitochondrial function and myofibrillar energetics (as part of a process referred to as 'metabolic remodelling'), which can all contribute to atrial dysfunction. In this Review, we discuss our current understanding of AF in the setting of metabolic disorders, as well as changes in atrial metabolism that are relevant to the development of AF. We also describe the potential of available and emerging treatment strategies to target metabolic remodelling in the setting of AF and highlight key questions and challenges that need to be addressed to improve outcomes in these patients.

Impact of Obesity on Atrial Electrophysiological Substrate

(1) Background. Obesity is a well-established worldwide recognised risk factor for atrial fibrillation (AF). Prior review papers reported on the associations between obesity and AF development, but not on the relation between obesity and atrial electrophysiology. We therefore conducted a systematic review to describe the current knowledge of the characteristics of the atrial electrophysiological substrate in obese individuals and how they relate to the development of AF. (2) Methods. A search was conducted in Pubmed, Embase, and the Cochrane Library for publications evaluating the impact of obesity on atrial electrophysiology, electrical substrates, and their relation to the development of AF. (3) Results. A systematic literature search retrieved 477 potential publications based on the inclusion criteria; 76 full-text articles were selected for the present systematic review. The literature demonstrated that obesity predisposes to not only a higher AF incidence but also to more extensive atrial electrophysiological abnormalities increasing susceptibility to AF development. (4) Conclusion. Obesity may predispose to an overall increase in atrial electropathology, consisting of an increase in the slowing of the conduction, conduction block, low-voltage areas, and complex fractionated electrograms. To determine the impact of obesity-induced atrial electrical abnormalities on the long-term clinical outcome, further prospective studies are mandatory.

Obesity-Related Atrial Fibrillation: Cardiac Manifestation of a Systemic Disease

Atrial fibrillation (AF) is the most common arrhythmia worldwide and is associated with increased morbidity and mortality. The mechanisms underlying AF are complex and multifactorial. Although it is well known that obesity is a strong risk factor for AF, the mechanisms underlying obesity-related AF are not completely understood. Current evidence proposes that in addition to overall hemodynamic changes due to increased body weight, excess adiposity raises systemic inflammation and oxidative stress, which lead to adverse atrial remodeling. This remodeling includes atrial fibrosis, atrial dilation, decreased electrical conduction between atrial myocytes, and altered ionic currents, making atrial tissue more vulnerable to both the initiation and maintenance of AF. However, much remains to be learned about the mechanistic links between obesity and AF. This knowledge will power the development of novel diagnostic tools and treatment options that will help combat the rise of the global AF burden among the obesity epidemic.

Adiposity-associated atrial fibrillation: molecular determinants, mechanisms, and clinical significance

Obesity is an important contributing factor to the pathophysiology of atrial fibrillation (AF) and its complications by causing systemic changes, such as altered haemodynamic, increased sympathetic tone, and low-grade chronic inflammatory state. In addition, adipose tissue is a metabolically active organ that comprises various types of fat deposits with discrete composition and localization that show distinct functions. Fatty tissue differentially affects the evolution of AF, with highly secretory active visceral fat surrounding the heart generally having a more potent influence than the rather inert subcutaneous fat. A variety of proinflammatory, profibrotic, and vasoconstrictive mediators are secreted by adipose tissue, particularly originating from cardiac fat, that promote atrial remodelling and increase the susceptibility to AF. In this review, we address the role of obesity-related factors and in particular specific adipose tissue depots in driving AF risk. We discuss the distinct effects of key secreted adipokines from different adipose tissue depots and their participation in cardiac remodelling. The possible mechanistic basis and molecular determinants of adiposity-related AF are discussed, and finally, we highlight important gaps in current knowledge, areas requiring future investigation, and implications for clinical management.

Weight loss and atrial fibrillation: a review

PURPOSE OF REVIEW

Despite technological advancements in catheter ablation, patients with atrial fibrillation often require multiple ablations, with diminishing returns depending on duration and persistence. Although early ablation is vital, modification of atrial fibrillation disease can be achieved with modification of existing risk factors. Obesity is an important modifiable risk factor, but there does not appear to be a consensus on the best method or goal for weight reduction.

RECENT FINDINGS

The relationship between atrial fibrillation and obesity has been acknowledged. This review examines the clinical evidence demonstrating the benefit of weight reduction in the management of atrial fibrillation. In particular, this review compares the different approaches of recent studies.

SUMMARY

On the basis of the literature, the authors recommend a structured weight loss programme with dietary and behavioural modifications individualized to each patient and including the implementation of physical activity. Consideration of bariatric surgery is appropriate in certain patients with obesity.

Obesity and Atrial Fibrillation: Epidemiology, Pathogenesis and Effect of Weight Loss

The obesity epidemic continues its relentless advance and is paralleled by an increase in the incidence of AF. Several epidemiological studies have highlighted obesity as an independent risk factor for the development of AF. This relationship is likely multifactorial through a number of interacting mechanisms. Weight loss through lifestyle changes or surgery has been associated with reverse remodelling of the atrial substrate and subsequent reduction in AF, making it an essential pillar in the management of AF in obese patients. In this review, the epidemiological data that support the obesity–AF relationship, the current insights into the underlying pathophysiological mechanism, the impact of weight loss on reverse remodelling and AF reduction, and the strategies to achieve weight loss in patients with AF are discussed.

Atrial Remodeling in Atrial Fibrillation. Comorbidities and Markers of Disease Progression Predict Catheter Ablation Outcome

Atrial fibrillation is the most common supraventricular arrhythmia affecting an increasing proportion of the population in which mainstream therapy, i.e. catheter ablation, provides freedom from arrhythmia in only a limited number of patients. Understanding the mechanism is key in order to find more effective therapies and to improve patient selection. In this review, the structural and electrophysiological changes of the atrial musculature that constitute atrial remodeling in atrial fibrillaton and how risk factors and markers of disease progression can predict catheter ablation outcome will be discussed in detail.

Beyond cardioversion, ablation and pharmacotherapies: Risk factors, lifestyle change and behavioral counseling strategies in the prevention and treatment of atrial fibrillation

IMPORTANCE

It has been suggested that atrial fibrillation (AF) is the new cardiovascular disease epidemic of the 21st century. Clinical cardiology has largely focused on AF treatment and associated stroke prevention rather than preventing AF itself. To reduce the global consequences and associated costs of AF, it is critical to now embrace prevention as a priority. Proactively addressing the risk factors for AF and the underlying unhealthy lifestyle habits that contribute to them, using research-based counseling approaches, represents a complementary and adjunctive alternative in combatting this disease burden.

OBSERVATIONS

Encouraging and sustaining patient involvement to reduce AF incidence and improve outcomes begins with screening to identify risk factors, unhealthy lifestyle habits, and characteristics associated with failed attempts at favorably modifying these causalities. Modulators of and common barriers to achieving risk reduction and lifestyle change include self-efficacy, social support, age, sex, marital and socioeconomic status, education, employment, and psychosocial factors such as depression, isolation, anxiety and chronic life stress. Focused behavioral counseling approaches, including assessing the patient's readiness to change, motivational interviewing and using the 5 A's (assess, advise, agree, assist, arrange), along with employing initial downscaled goals to overcome inertia, are proven methodologies to overcome these common barriers to favorably modifying risk factors and unhealthy lifestyle habits.

CONCLUSIONS AND RELEVANCE

To complement and enhance the current armamentarium for the medical management of cardiac arrhythmias, there is an urgent need to proactively address the causative factors triggering new-onset, recurrent and persistent AF. Beyond the counseling skills of highly trained professionals (eg, psychiatrists, psychologists), this narrative review highlights the need for and potential impact on lifestyle modification that non-behavioral scientists, including internal medicine, cardiology, and allied health professionals, can have on the patients they serve.

Inhibition of endoplasmic reticulum stress prevents high-fat diet mediated atrial fibrosis and fibrillation

Obesity is a significant risk factor for atrial fibrillation (AF), which is the most common sustained arrhythmia with increased mortality and morbidity. High-fat diet (HFD)-induced obesity is associated with the activation of endoplasmic reticulum stress (ERS). However, the role of ERS in HFD-induced AF remains elusive. Human atrium samples were examined for the ERS activation test. C57BL/6J mice were divided into four groups, including the control group, the HFD group, the 4-phenylbutyric acid (4-PBA) group, and the HFD + 4-PBA group. At the age of 4 weeks, the HFD group and the HFD + 4-PBA group were given HFD to construct the obesity model, while the other two groups were given a normal diet (ND). Transesophageal programmed electrical stimulation was conducted to evaluate the AF inducibility and duration. Atrial fibrosis and ERS activation were also investigated.We found that CHOP and GRP-78 protein were significantly higher in overweight patients than the controls (both P < 0.05). AF inducibility and duration of the HFD group were significantly higher than the other groups (both P < 0.05), while there was no difference between those groups (P > 0.05). The mice of the HFD group had significantly higher collagen volume fraction (CVF%) than the other groups (P < 0.05). ERS marker protein of GRP78, p-PERK, ATF6 and CHOP protein expression level was increased in the HFD group, which were significantly mitigated in the HFD + 4-PBA group. In summary, HFD-induced ERS activation facilitates atrial fibrosis and AF. The inhibition of ERS might alleviate atrial fibrosis and reduce the incidence of AF-associated obesity.

Atrial Fibrillation Structural Substrates: Aetiology, Identification and Implications

Atrial remodelling in AF underlines the electrical, structural and mechanical changes in the atria of patients with AF. Several risk factors for AF contribute to the development of the atrial substrate, with some evidence that atrial remodelling reversal is possible with targeted intervention. In this article, the authors review the electrophysiological changes that characterise the atrial substrate in patients with AF risk factors. They also discuss the pitfalls of mapping the atrial substrate and the implications for developing tailored ablation strategies to improve outcomes in patients with AF.

Lifestyle and Risk Factor Modification for Reduction of Atrial Fibrillation: A Scientific Statement From the American Heart Association

Atrial fibrillation (AF), the most common sustained cardiac arrhythmia, is associated with substantial morbidity, mortality, and healthcare use. Great strides have been made in stroke prevention and rhythm control strategies, yet reducing the incidence of AF has been slowed by the increasing incidence and prevalence of AF risk factors, including obesity, physical inactivity, sleep apnea, diabetes mellitus, hypertension, and other modifiable lifestyle-related factors. Fortunately, many of these AF drivers are potentially reversible, and emerging evidence supports that addressing these modifiable risks may be effective for primary and secondary AF prevention. A structured, protocol-driven multidisciplinary approach to integrate lifestyle and risk factor management as an integral part of AF management may help in the prevention and treatment of AF. However, this aspect of AF management is currently underrecognized, underused, and understudied. The purpose of this American Heart Association scientific statement is to review the association of modifiable risk factors with AF and the effects of risk factor intervention. Implementation strategies, care pathways, and educational links for achieving impactful weight reduction, increased physical activity, and risk factor modification are included. Implications for clinical practice, gaps in knowledge, and future directions for the research community are highlighted.