P-wave dispersion and maximum duration are independently associated with insulin resistance in metabolic syndrome

The Impact of Metabolic Syndrome on the Incidence of Atrial Fibrillation: A Nationwide Longitudinal Cohort Study in South Korea

Aims: To evaluate the impact of metabolic syndrome (MetS) status on the incidence of atrial fibrillation (AF) in Koreans. Methods and results: Data obtained from the Korean National Health Insurance Service from 2009 to 2016 were analyzed. In total, 7,830,602 men and women (between 30 and 69 years of age) without baseline AF who underwent a national health examination between January 2009 and December 2009 were enrolled. Patients were evaluated to determine the impact of MetS status on their risk of developing AF until December 2016. Using the National Cholesterol Education Program Adult Treatment Panel III criteria, patients were placed into one of three groups depending on MetS component numbers: 0 (normal), 1–2 (Pre-MetS) or 3–5 (MetS). During a mean follow-up of 7.3 years, 20,708 subjects (0.26%) were diagnosed with AF. After multivariable adjustment, the risk of AF was significantly and positively correlated with MetS status (hazard ratios (HR) 1.391, 95% confidence interval (CI) 1.322–1.464 in Pre-MetS and HR 1.722, 95% CI 1.621–1.829 in MetS). When subgroup analyses were conducted according to MetS components, abdominal obesity (HR 1.316, p < 0.001), elevated blood pressure (HR 1.451, p < 0.001), and elevated fasting glucose (HR 1.163, p < 0.001) were associated with an increased risk of AF. Conclusion: MetS and pre-MetS are significantly associated with an increased risk of AF in Korean adults. Of the MetS components, abdominal obesity, elevated blood pressure, and elevated fasting glucose are potent risk factors for the risk of AF in this population.

Serum androgens and risk of atrial fibrillation in older men: The Cardiovascular Health Study

BACKGROUND

Decline in serum androgens is common among older men and has been associated with cardiovascular disease, although its role in risk of atrial fibrillation (AF) has not been well defined.

HYPOTHESIS

Low serum androgens are associated with an increased risk of AF.

METHODS

We examined the prospective associations between testosterone, its more active metabolite dihydrotestosterone (DHT), and sex hormone-binding globulin (SHBG) with risk of AF among 1019 otherwise healthy men with average age 76.3 ±4.9 years in the Cardiovascular Health Study.

RESULTS

After median follow-up of 9.5 years, 304 (30%) men developed AF. We detected a nonlinear association with risk of incident AF in both free and total DHT, in which subjects with the lowest levels had a higher risk of incident AF. After adjustment for demographics, clinical risk factors, left atrial diameter, and serum NT-proBNP levels, men with free DHT <0.16 ng/dL were at increased risk compared with men with higher levels (hazard ratio: 1.48, 95% confidence interval: 1.01-2.17, P <0.05). Sensitivity analyses confirmed that the increased risk was not cutpoint-specific, with a significant association noted up to cutpoints <~0.2 ng/dL. We also detected a complex nonlinear association between SHBG and incident AF, in which subjects in the middle quintile (52.9-65.3 nmol/L) had increased risk.

CONCLUSIONS

Among older men, low free DHT is associated with an increased risk of incident AF. Further studies are needed to explore mechanisms for this association.

Linking atrial fibrillation with non-alcoholic fatty liver disease: potential common therapeutic targets

Non-alcoholic fatty liver disease (NAFLD) and atrial fibrillation (AF) are common chronic non-infectious diseases with rising incidences. NAFLD is an independent risk factor for the onset of AF, after adjusting potentially related factors. The pathogenesis of these diseases share several mechanisms including reduced adiponectin level, insulin resistance, and renin angiotensin aldosterone system (RAAS) activation, in addition to activation of common disease pathways that promote inflammation, oxidative stress, and fibrosis. Furthermore, statins and RAAS blockers exert therapeutic effects concurrently on NAFLD and AF. The common pathogenesis of NAFLD and AF may serve as a potential therapeutic target in the future.

Correlation of P-wave dispersion with insulin sensitivity in obese adolescents

BACKGROUND

P-wave dispersion is a new and simple electrocardiographic marker that has been reported to be associated with inhomogeneous and discontinuous propagation of sinus impulses. In the present study, we evaluated P-wave dispersion in obese adolescents and investigated the relationship between P-wave dispersion, cardiovascular risk factors, and echocardiographic parameters.

METHODS

We carried out a case-control study comparing 150 obese adolescents and 50 healthy controls. Maximum and minimum P-wave durations were measured using a 12-lead surface electrocardiogram, and P-wave dispersion was calculated as the difference between these two measures. Echocardiographic examination was also performed for each subject. Multivariate linear regression analysis with stepwise variable selection was used to evaluate parameters associated with increased P-wave dispersion in obese subjects.

RESULTS

Maximum P-wave duration and P-wave dispersion were significantly higher in obese adolescents than control subjects (143±19 ms versus 117±20 ms and 49±15 ms versus 29±9 ms, p<0.0001 for both). P-wave dispersion was positively correlated with body mass index, waist and hip circumferences, systolic and diastolic blood pressures, total cholesterol, serum levels of low-density lipoprotein cholesterol, triglycerides, glucose, and insulin, homoeostasis model assessment for insulin resistance score, left ventricular mass, and left atrial dimension. P-wave dispersion was negatively correlated with high-density lipoprotein cholesterol levels. By multiple stepwise regression analysis, left atrial dimension (β: 0.252, p=0.008) and homoeostasis model assessment for insulin resistance (β: 0.205; p=0.009) were independently associated with increased P-wave dispersion in obese adolescents.

CONCLUSIONS

Insulin resistance is a significant, independent predictor of P-wave dispersion in obese adolescents.

Obesity and atrial fibrillation: A comprehensive review of the pathophysiological mechanisms and links

Obesity is a worldwide health problem with epidemic proportions that has been associated with atrial fibrillation (AF). Even though the underlying pathophysiological mechanisms have not been completely elucidated, several experimental and clinical studies implicate obesity in the initiation and perpetuation of AF. Of note, hypertension, diabetes mellitus, metabolic syndrome, coronary artery disease, and obstructive sleep apnea, represent clinical correlates between obesity and AF. In addition, ventricular adaptation, diastolic dysfunction, and epicardial adipose tissue appear to be implicated in atrial electrical and structural remodeling, thereby promoting the arrhythmia in obese subjects. The present article provides a concise overview of the association between obesity and AF, and highlights the underlying pathophysiological mechanisms.