Liver enzymes are not directly involved in atrial fibrillation: a prospective cohort study

Nonalcoholic Fatty Liver Disease: An Emerging Driver of Cardiac Arrhythmia

Cardiac arrhythmias and the resulting sudden cardiac death are significant cardiovascular complications that continue to impose a heavy burden on patients and society. An emerging body of evidence indicates that nonalcoholic fatty liver disease (NAFLD) is closely associated with the risk of cardiac arrhythmias, independent of other conventional cardiometabolic comorbidities. Although most studies focus on the relationship between NAFLD and atrial fibrillation, associations with ventricular arrhythmias and cardiac conduction defects have also been reported. Mechanistic investigations suggest that a number of NAFLD-related pathophysiological alterations may potentially elicit structural, electrical, and autonomic remodeling in the heart, contributing to arrhythmogenic substrates in the heart. NAFLD is now the most common liver and metabolic disease in the world. However, the upsurge in the prevalence of NAFLD as an emerging risk factor for cardiac arrhythmias has received little attention. In this review, we summarize the clinical evidence and putative pathophysiological mechanisms for the emerging roles of NAFLD in cardiac arrhythmias, with the purpose of highlighting the notion that NAFLD may serve as an independent risk factor and a potential driving force in the development and progression of cardiac arrhythmias.

Direct bilirubin level is an independent risk factor for atrial fibrillation in thyrotoxic patients receiving radioactive iodine therapy

OBJECTIVES

This study aimed to indicate the risk factors of atrial fibrillation (AF) in thyrotoxic patients receiving radioactive iodine (RAI) therapy after antithyroid drug and other medication.

METHODS

This study was a retrospective cohort study. Thyrotoxic patients were divided into two groups, with or without AF. Clinical features were retrospectively analyzed. Univariate and multivariate analyses of data from thyrotoxic patients were performed to evaluate the probability of AF.

RESULTS

The following clinical factors were found to be correlated with AF: age, gender, duration of hyperthyroidism, coronary artery disease, hypertension, and levels of platelets, creatinine, uric acid (UA), and certain liver enzymes. According to the multiple logistic regression model, age and levels of UA, direct bilirubin (DBIL), and gamma-glutamyl transpeptidase (GGT) were important risk factors for predicting AF. ROC analysis showed that DBIL levels were predictive of AF, with a specificity of 0.813, a sensitivity of 0.767, and an area under the curve of 0.8515 (P < 0.001).

CONCLUSION

Older age and levels of UA, DBIL, and GGT influenced the occurrence of AF in thyrotoxic patients receiving RAI. DBIL level was an important factor in predicting AF in patients with hyperthyroidism. Thus, thyrotoxic patients who have the above-mentioned risk factors should undergo routine pulse palpation should be considered for active antithyroid drug therapy.

The association of non-alcoholic fatty liver disease and atrial fibrillation: a review

Non-alcoholic fatty liver disease (NAFLD) is highly prevalent and causes an enormous burden to human health and health-care systems all over the world. A great proportion of this burden results from increased risk of cardiovascular diseases. Atrial fibrillation (AF) is the most common chronic heart arrhythmia globally and it increases the risk of embolic stroke and heart failure. Recent studies have explored the association between NAFLD and AF with somewhat conflicting results. However, ultrasound-verified prospective studies concur that NAFLD is associated with the incidence of AF. According to epidemiological evidence, the greater the prevalence of NALFD in a population, the stronger the association with AF incidence and prevalence. Specifically, diabetic individuals with NAFLD are at the greatest risk of AF. Additionally, the risk of AF may concentrate most in individuals with advanced NAFLD, particularly those with liver fibrosis. The possible mechanistic factors between NAFLD and AF, particularly obesity and systemic inflammation, are diverse and form a complex interplaying network. However, further studies are needed to elucidate whether NAFLD has a causative role in the development of AF. The purpose of this article is to review and discuss the epidemiologic evidence and possible mechanistic links between these two conditions. KEY MESSAGES Although epidemiologic studies have provided conflicting results on the association of NAFLD and AF, prospective studies with ultrasound-verified NAFLD concur that NAFLD is associated with about 2-fold greater incidence of AF among general population and about 6-fold greater incidence among subjects with type 2 diabetes. The risk of AF among individuals with NAFLD is increased by other cardiovascular risk factors, especially type 2 diabetes and advanced age. The possible mechanistic links between NALFD and AF are diverse, with obesity and systemic inflammation having a significant role, but further studies are needed until NAFLD can be established as a causal factor in the incidence of AF.