Pericardial fat and atrial conduction abnormalities in the Multiethnic Study of Atherosclerosis (MESA)

The dysfunctional adiposity index is a clinical surrogate of pericardial fat in adults without premature CVD: A sub-analysis of the GEA Mexican study control group

BACKGROUND AND AIM

The Dysfunctional Adiposity Index (DAI) is a clinical surrogate for evaluating adipose tissue functionality and cardiometabolic health. However, its association with Pericardial Fat Volume (PFV) has not been tested. The aim of this study was to evaluate DAI- PFV association, stratified by type 2 diabetes (T2D) status, and identify DAI thresholds for detecting increased PFV among patients without premature CVD.

METHODS AND RESULTS

Participants from the GEA-Mexican study underwent a computed tomography scan to measure PFV. Adjusted logistic regression analyses tested the association between DAI and PFV. AUROC curves evaluated DAI's ability to identify elevated PFV (≥57.57 cm³), and the Youden method determined DAI thresholds, along with diagnostic metrics. The study analyzed 997 participants (women: 55%; mean age: 54 ± 9 years; median PFV: 42 cm³ [IQR: 29-58]), with a 13% prevalence of T2D. DAI was positively associated with elevated PFV (OR: 1.33, 95% CI: 1.07-1.70), which was more pronounced among subjects with T2D (OR: 3.01, 95% CI: 1.41-6.40). DAI thresholds were established for all participants (>1.176), individuals without T2D (>1.003), and with T2D (>1.936), yielding sensitivities of 71%, 81%, and 57%, and specificities of 48%, 38%, and 75%, respectively. The adjusted logistic regression tied DAI thresholds to a 1.68-fold elevation in PFV for all, 2.06-fold for those without T2D, and 6.81-fold for those with T2D.

CONCLUSION

DAI was positively associated with increased PFV, particularly among participants with T2D. Established DAI thresholds demonstrated good diagnostic values for detecting increased PFV. DAI could serve as an accessible marker to identify PF in clinical settings.

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.

Clinical and biological determinants of P-wave duration: cross-sectional data from the population-based CoLaus|PsyCoLaus study

OBJECTIVES

P-wave duration (PWD) is associated with the development of atrial arrhythmias, cardiovascular and all-cause mortality. With this study, we aimed to assess the distribution and determinants of PWD in the general population.

DESIGN

Cross-sectional study using data collected between 2014 and 2016.

SETTING

In the population-based cohort CoLaus|PsyCoLaus, Lausanne, Switzerland, we used 12-lead ECGs to measure PWD. Potential demographic, clinical and biological determinants of PWD were collected by questionnaire, anthropometry, blood pressure measurement and biological assays.

PARTICIPANTS

Data from 3459 participants (55% women, 62±10 years, 93% Caucasian) were included. Participants were excluded if they presented with (1) no sinus rhythm or paced rhythm on the study ECG or Wolff-Parkinson-White ECG pattern; (2) missing or non-interpretable ECG; and (3) missing phenotypic data.

PRIMARY OUTCOME MEASURE

Determine (1) the PWD distribution and (2) the demographic, clinical and biological determinants of PWD in a large population-based cohort.

RESULTS

Median and IQR of PWD was 112 (102-120) ms . In the multivariable analyses, PWD was significantly associated with age (p<0.001) and height (p<0.001), with an adjusted regression coefficient (95% CI) of 0.29 ms/years (0.23 to 0.36) and 0.32 ms/cm (0.28 to 0.37), respectively. PWD, given thereafter in ms with adjusted mean±SE, was significantly (p<0.05) associated with (a) gender (woman 110.0±0.4; man 112.1±0.4), (b) body mass index (normal 110.1±0.4; overweight 110.9±0.4; obese 113.0±0.5), (c) abdominal obesity (no 110.5±0.3; yes 111.7±0.4) and (d) hypertension (no 110.4±0.3; yes 111.7±0.4).

CONCLUSION

PWD is positively associated with age, height, male gender, obesity markers and hypertension. Clinical interpretation of PWD should take these factors into consideration.

Lipidomics, Atrial Conduction, and Body Mass Index

BACKGROUND

Lipids are increasingly involved in cardiovascular risk prediction as potential proarrhythmic influencers. However, knowledge is limited about the specific mechanisms connecting lipid alterations with atrial conduction.

METHODS

To shed light on this issue, we conducted a broad assessment of 151 sphingo- and phospholipids, measured using mass spectrometry, for association with atrial conduction, measured by P wave duration (PWD) from standard electrocardiograms, in the MICROS study (Microisolates in South Tyrol) (n=839). Causal pathways involving lipidomics, body mass index (BMI), and PWD were assessed using 2-sample Mendelian randomization analyses based on published genome-wide association studies of lipidomics (n=4034) and BMI (n=734 481), and genetic association analysis of PWD in 5 population-based studies (n=24 236).

RESULTS

We identified an association with relative phosphatidylcholine 38:3 (%PC 38:3) concentration, which was replicated in the ORCADES (Orkney Complex Disease Study; n=951), with a pooled association across studies of 2.59 (95% CI, 1.3-3.9; P=1.1×10^-4) ms PWD per mol% increase. While being independent of cholesterol, triglycerides, and glucose levels, the %PC 38:3-PWD association was mediated by BMI. Results supported a causal effect of BMI on both PWD ( P=8.3×10^-5) and %PC 38:3 ( P=0.014).

CONCLUSIONS

Increased %PC 38:3 levels are consistently associated with longer PWD, partly because of the confounding effect of BMI. The causal effect of BMI on PWD reinforces evidence of BMI's involvement into atrial electrical activity.

Independent associations of blood pressure and body mass index with interatrial block: a cross-sectional study in general Chinese population

OBJECTIVES

This current study was performed to characterise the independent associations of obesity and hypertension with interatrial block (IAB) after adjusting for cardiovascular risk factors, echocardiographic left atrial diameter (LAD) and left ventricular mass index (LVMI) in a large general Chinese population.

DESIGN

A cross-sectional study.

SETTING AND PARTICIPANTS

A total of 11 956 permanent residents (≥35 years of age) from Liaoning Province in China were included in this study. Following the completion of a questionnaire, the enrolled participants were subjected to physical examinations, laboratory analyses, ECG and echocardiogram. Linear and logistic regression analyses were performed to evaluate the associations of hypertension and obesity with IAB.

OUTCOME MEASURES

IAB was defined as a prolongation of the P wave duration ≥120 ms on a digital 12-lead ECG.

RESULTS

The prevalence of IAB in hypertensive individuals was higher than the normotensive in both men (9.5 vs 5.9%; p<0.001) and women (6.6 vs 3.6%; p<0.001). In addition, the prevalence of IAB exhibited a sharp increase with advancing body mass index (BMI) in both men (from 4.9% to 13.0%) and women (from 3.5% to 6.9%) (ps- for trend <0.001). Multiple relevant clinical covariates, echocardiographic LAD and LVMI were adjusted in the multivariate linear and logistic regression analyses. The results revealed that systolic blood pressure, diastolic blood pressure and BMI were all independently associated with P wave duration (β=0.02, 0.09 and 0.25, respectively; all ps <0.005). Furthermore, hypertension was found to be independently associated with IAB (OR=1.27; p=0.018), while both overweight and obesity exhibited higher odds of IAB (OR=1.42 and 1.67, respectively; ps <0.005), compared with BMI <24.0 kg/m².

CONCLUSIONS

The key findings of this study highlighted that hypertension and overweight/obesity were independently and significantly associated with IAB in general Chinese population.

Body mass index related electrocardiographic findings in healthy young individuals with a normal body mass index

INTRODUCTION

An increased body mass index (BMI) (>25 kg/m²) is associated with a wide range of electrocardiographic changes. However, the association between electrocardiographic changes and BMI in healthy young individuals with a normal BMI (18.5-25 kg/m²) is unknown. The aim of this study was to evaluate the association between BMI and electrocardiographic parameters.

METHODS

Data from 1,290 volunteers aged 18 to 30 years collected at our centre were analysed. Only subjects considered healthy by a physician after review of collected data with a normal BMI and in sinus rhythm were included in the analysis. Subjects with a normal BMI (18.5-25 kg/m²) were divided into BMI quartiles analysis and a backward multivariate regression analysis with a normal BMI as a continuous variable was performed.

RESULTS

Mean age was 22.7 ± 3.0 years, mean BMI was 22.0, and 73.4% were male. There were significant differences between the BMI quartiles in terms of maximum P-wave duration, P-wave balance, total P-wave area in lead V1, PR-interval duration, and heart axis. In the multivariate model maximum P-wave duration (standardised coefficient (SC) = +0.112, P < 0.001), P-wave balance in lead V1 (SC = +0.072, P < 0.001), heart axis (SC = -0.164, P < 0.001), and Sokolow-Lyon voltage (SC = -0.097, P < 0.001) were independently associated with BMI.

CONCLUSION

Increased BMI was related with discrete electrocardiographic alterations including an increased P-wave duration, increased P-wave balance, a leftward shift of the heart axis, and decreased Sokolow-Lyon voltage on a standard twelve lead electrocardiogram in healthy young individuals with a normal BMI.

Index of cardiac electrophysiological balance and transmural dispersion of the repolarization index relationships with pericardial fat volume and coronary calcification

AIM

To assess the possible relationship between coronary atherosclerosis markers, pericardial fat volume (PFV) and coronary artery calcification, with ECG markers of index of the cardiac electrophysiological balance (iCEB) and transmural dispersion of the repolarization in patients with suspected coronary artery disease.

METHODOLOGY

One hundred patients who underwent 64-slice multidetector computed tomography angiography were found to be eligible and were enrolled in the study.

RESULTS

Patients with high iCEB levels tended to have a higher PFV values compared with patients with low iCEB levels (median [interquartile range]) (152 [29-206] vs 96 [14-177]; p = 0.03). No significant differences in coronary artery calcification values were observed between iCEB and transmural dispersion of the repolarization groups.

CONCLUSION

A higher PFV value was observed in patients with high iCEB. Larger prospective studies are required to confirm the results.

Atrial electrocardiography in obesity and hypertension: Clinical insights from the Polish-Norwegian Study (PONS)

OBJECTIVE

Obesity and hypertension often coexist and represent risk factors for atrial fibrillation. This study hypothesized that their single and joint effects on atrial remodeling would be reflected in the PR interval and P-wave durations on electrocardiogram (ECG).

METHODS

This cross-sectional analysis of a community-based study included 11,308 men and women age 45-64. Atrial indices were obtained from digital standard 12-lead resting ECG. Analyses were adjusted for traditional cardiovascular risk factors.

RESULTS

Both ECG indices displayed a progressive increase across anthropometric indices. Each 5-unit increment in body mass index (BMI) increased P-wave duration by 1.9 ms (95% CI 1.5-2.2) and PR interval by 2.4 ms (95% CI 1.9-3.0), with similar trends for central obesity, even among those without obesity by BMI. Both ECG indices displayed graded increases across levels of blood pressure control, including prehypertension. A joint effect of overweight and hypertension on both ECG indices was detected. P-wave duration or PR interval among people with obesity was not additionally increased by hypertension.

CONCLUSIONS

P-wave indices increase in general and central obesity. Hypertension exerts an incremental effect in people with overweight but not in people with obesity. The study furthered the understanding of atrial remodeling in the setting of major atrial fibrillation risk factors.

The Associations between Various Ectopic Visceral Adiposity and Body Surface Electrocardiographic Alterations: Potential Differences between Local and Remote Systemic Effects

Background

The associations between pericardial adiposity and altered atrial conduction had been demonstrated. However, data comparing differential effects of various body sites visceral adiposity on atrial and ventricular electrocardiographic alterations remains largely unknown.

Methods and Results

We assessed both peri-cardial fat (PCF) and peri-aortic visceral adiposity (TAT) using dedicated computed tomography (CT) software (Aquarius 3D Workstation, TeraRecon, San Mateo, CA, USA), with anthropometrics including body mass index (BMI) and biochemical data obtained. We further related PCF and TAT data to standardized 12-leads electrocardiogram (ECG), including P and QRS wave morphologies. Among 3,087 study subjects (mean age, 49.6 years; 28% women), we observed a linear association among greater visceral adiposity burden, leftward deviation of P and QRS axes, longer PR interval and widened QRS duration (all p<0.001). These associations became attenuated after accounting for BMI and baseline clinical co-variates, with greater PCF remained independently associated with prolonged QRS duration (β = 0.91 [95% CI: 0.52, 1.31] per 1-SD increase in PCF, p<0.001). Finally, both PCF and TAT showed incremental value in identifying abnormally high PR interval (>200ms, likelihood-ratio: 33.17 to 41.4 & 39.03 for PCF and TAT) and widened QRS duration (>100ms, likelihood-ratio: 55.67 to 65.4 & 61.94 for PCF and TAT, all X² p<0.05) when superimposed on age and BMI.

Conclusion

We show in our data greater visceral fat burden may have differential associations on several body surface electrocardiographic parameters. Compared to remote adiposity, those surrounding the heart tissue demonstrated greater influences on altered cardiac activation or conduction, indicating a possible local biological effect.

An observational study of the association among interatrial adiposity by computed tomography measure, insulin resistance, and left atrial electromechanical disturbances in heart failure

Excessive visceral adiposity, hypothesized to be a key mediator in metabolic derangements, has recently been shown to exert toxic effects on cardiac structure and function. Data regarding the mechanistic link between regional adiposity, left atrial (LA) electromechanical remodeling, and heart failure with preserved ejection fraction (HFpEF) have been lacking.Various visceral adiposity measures, including pericardial fat (PCF), thoracic periaortic (TAT) fat, regional inter-atrial fat (IAF), and atrioventricular groove fat (AV Groove Fat), were assessed by multidetector computed tomography in 2 study cohorts (an annual health survey cohort and an outpatient cohort). We related such measures to cardiometabolic profiles in health survey cohort and LA electromechanical indices in our outpatient cohort, with Cox proportional hazards performed to examine the temporal trends of heart failure (HF).In our annual health survey cohort (n = 362), all 4 adiposity measures were positively related to unfavorable anthropometrics and systemic inflammation (high-sensitivity C-reactive protein) (all P < 0.05). In addition, both greater IAF and AV Groove Fat were positively associated with higher fasting glucose, HbA1c levels, and insulin resistance (all P < 0.05). In the outpatient cohort, the HFpEF group demonstrated the greatest adiposity measures, with greater IAF (≥8.2 mm, hazard ratio: 4.11, 95% confidence interval: 1.50-11.32) associated with reduced LA strain (ß-coef: -0.28), higher LA stiffness (ß-coef: 0.23), and longer P wave duration (ß-coef: 0.23) in multivariate models (all P < 0.05), and further related to higher HF hospitalization during follow-up.We therefore propose a possible pathophysiologic link among greater visceral adiposity, systemic inflammation, cardiometabolic risks, and HFpEF. Regional adiposity, especially IAF, was tightly linked to altered LA electromechanical properties and likely plays a key role in HF prognosis.

Sex-specific cardiovascular responses to control or high fat diet feeding in C57bl/6 mice chronically exposed to bisphenol A

The increased pericardial fat which often accompanies overall obesity is thought to alter cardiac structure/function and increase the risk for atrial fibrillation. We hypothesized that chronic exposure to bisphenol A (BPA) would induce pericardial fat, cardiac hypertrophy or arrhythmia. C57bl/6n dams were exposed to BPA (25 ng/ml drinking water) beginning on gestation day 11 and progeny continued on 2.5 ng BPA/ml drinking water. The progeny of control dams (VEH) and dams treated with diethylstilbestrol (DES, 1 μg/kg/day, gestation days 11⿿14) had tap water. After weaning progeny were fed either a control (CD) or high fat diet (HFD) for 3 months. Pericardial fat was present in CD-BPA and CD-DES and not CD-VEH mice, and was increased in all HFD mice. Catecholamine challenge revealed no differences in males, but BPA-exposed females had longer P-wave and QRS complex duration. Only CD-BPA and CD-DES females developed cardiac hypertrophy which was independent of increased blood pressure. Calcium homeostasis protein expression changes in HFD-BPA and HFD-DES mice predict reduced SERCA2 activity in males and increased SERCA2 activity in females. Thus, chronic BPA exposure induced pericardial fat in the absence of HFD, and female-specific changes in cardiac hypertrophy development and cardiac electrical conduction after a catecholamine challenge.

The association between atrium electromechanical interval and pericardial fat

OBJECTIVES

Pericardial fat (PCF) may induce local inflammation and subsequent structural remodeling of the left atrium (LA). However, the adverse effects of PCF on LA are difficult to be evaluated and quantified. The atrial electromechanical interval determined by transthoracic echocardiogram was shown to be a convenient parameter which can reflect the process of LA remodeling. The goal of the present study was to investigate the association between the electromechanical interval and PCF.

METHODS AND RESULTS

A total of 337 patients with mean age of 51.9 ± 9.0 years were enrolled. The electromechanical interval (PA-PDI) defined as the time interval from the initiation of the P wave deflection to the peak of the mitral inflow A wave on the pulse wave Doppler imaging was measured for every patient. The amount of PCF was determined by multi-detector computed tomography. The PA-PDI interval was significantly correlated with the amount of PCF (r = 0.641, p value <0.001). Graded prolongation of PA-PDI interval was observed across 3 groups of patients divided according to the tertile values of PCF. The AUC for the PA-PDI interval in predicting an increased amount of PCF (third tertile) was 0.796. At a cutoff value of 130 ms identified by the ROC curve, the sensitivity and specificity of PA-PDI interval in identifying patients with a highest tertile of PCF were 63.4% and 85.3%, respectively.

CONCLUSIONS

The PA-PDI intervals were longer in patients with an increased amount of PCF. It may be a useful parameter to represent the degree of PCF-related atrial remodeling.

Pericardial fat is associated with atrial conduction: the Framingham Heart Study

Background

Obesity is associated with altered atrial electrophysiology and a prominent risk factor for atrial fibrillation. Body mass index, the most widely used adiposity measure, has been related to atrial electrical remodeling. We tested the hypothesis that pericardial fat is independently associated with electrocardiographic measures of atrial conduction.

Methods and Results

We performed a cross‐sectional analysis of 1946 Framingham Heart Study participants (45% women) to determine the relation between pericardial fat and atrial conduction as measured by P wave indices (PWI): PR interval, P wave duration (P‐duration), P wave amplitude (P‐amplitude), P wave area (P‐area), and P wave terminal force (P‐terminal). We performed sex‐stratified linear regression analyses adjusted for relevant clinical variables and ectopic fat depots. Each 1‐SD increase in pericardial fat was significantly associated with PR interval (β=1.7 ms, P=0.049), P‐duration (β=2.3 ms, P<0.001), and P‐terminal (β=297 μV·ms, P<0.001) among women; and P‐duration (β=1.2 ms, P=0.002), P‐amplitude (β=−2.5 μV, P<0. 001), and P‐terminal (β=160 μV·ms, P=0.002) among men. Among both sexes, pericardial fat was significantly associated with P‐duration in analyses additionally adjusting for visceral fat or intrathoracic fat; a similar but non‐significant trend existed with P‐terminal. Among women, pericardial fat was significantly associated with P wave area after adjustment for visceral and intrathoracic fat.

Conclusions

Pericardial fat is associated with atrial conduction as quantified by PWI, even with adjustment for extracardiac fat depots. Further studies are warranted to identify the mechanisms through which pericardial fat may modify atrial electrophysiology and promote subsequent risk for arrhythmogenesis.

Electrocardiographic changes associated with insulin resistance

BACKGROUND AND AIM

Cardiac steatosis has been related to increased risk of heart disease. We investigated the association between cardiac steatosis, electrocardiographic (ECG) abnormalities, and individual components of the metabolic syndrome (MetS).

METHODS AND RESULTS

A 12-lead ECG and laboratory data were examined in 31 men with the MetS and in 38 men without the MetS. Myocardial triglyceride (MTG) content was measured with 1.5 T magnetic resonance (MR) spectroscopy and epicardial and pericardial fat by MR imaging. MTG content, epicardial and pericardial fat depots were higher in men with the MetS compared with subjects without the MetS (p < 0.001). The heart rate was increased (p < 0.001), the PR interval was longer (p < 0.044), the frontal plane QRS axis shifted to the left (p < 0.001), and the QRS voltage (p < 0.001) was lower in subjects with the MetS. The frontal plane QRS axis and the QRS voltage were inversely correlated with MTG content, waist circumference (WC), body mass index (BMI), TGs, and fasting blood glucose. High-density lipoprotein cholesterol correlated positively and measures of insulin resistance negatively with the QRS voltage. MTG content and hypertriglyceridemia were determinants of the frontal plane QRS and WC and hyperglycemia were predictors of the QRS voltage.

CONCLUSION

The MetS and cardiac steatosis appear to associate with multiple changes on 12-lead ECG. The frontal plane QRS axis is shifted to the left and the QRS voltage is lower in subjects with the MetS. Standard ECG criteria may underestimate the presence of left ventricular hypertrophy in obese subjects with cardiometabolic risk factors.

Reference ranges of PR duration and P-wave indices in individuals free of cardiovascular disease: the Multi-Ethnic Study of Atherosclerosis (MESA)

In this brief report, we provide normal reference ranges for PR duration [unadjusted and heart rate adjusted] and P-wave indices [duration, amplitude and terminal force in V1] in individuals free of cardiovascular disease and its risk factors. We used automatically processed digital ECG data from 1252 US participants [mean age 59 (± 10) years, 738 women, 588 whites, 207 African-Americans, 217 Hispanics, 240 Chinese] from the Multi-Ethnic Study of Atherosclerosis [MESA]. In multivariable adjusted linear regression models with PR and each P-wave variable as a separate outcome, significant age, sex and race differences in these markers were observed. Subsequently, we report reference ranges for abnormal [2nd and 98th percentiles], borderline abnormal [5th and 95th percentiles] and mean [SD] values of PR and P-wave indices stratified by age [middle age (45-64 years) and seniors (65-84 years)], sex [men and women] and race [whites, African Americans, Hispanics and Chinese].

The melanocortin-4 receptor as target for obesity treatment: a systematic review of emerging pharmacological therapeutic options

Obesity is one of the greatest public health challenges of the 21st century. Obesity is currently responsible for ∼0.7-2.8% of a country's health costs worldwide. Treatment is often not effective because weight regulation is complex. Appetite and energy control are regulated in the brain. Melanocortin-4 receptor (MC4R) has a central role in this regulation. MC4R defects lead to a severe clinical phenotype with lack of satiety and early-onset severe obesity. Preclinical research has been carried out to understand the mechanism of MC4R regulation and possible effectors. The objective of this study is to systematically review the literature for emerging pharmacological obesity treatment options. A systematic literature search was performed in PubMed and Embase for articles published until June 2012. The search resulted in 664 papers matching the search terms, of which 15 papers remained after elimination, based on the specific inclusion and exclusion criteria. In these 15 papers, different MC4R agonists were studied in vivo in animal and human studies. Almost all studies are in the preclinical phase. There are currently no effective clinical treatments for MC4R-deficient obese patients, although MC4R agonists are being developed and are entering phase I and II trials.

Maternal autoantibodies in autism

As epidemiologic studies continue to note a striking increase in rates of autism spectrum disorder (ASD) diagnosis around the world, the lack of identified causative agents in most cases remains a major hindrance to the development of treatment and prevention strategies. Published observations of immune system abnormalities in ASD have increased recently, with several groups identifying fetal protein reactive IgG antibodies in plasma from mothers of children with autism. Furthermore, other gestational immune parameters, including maternal infection and dysregulated cytokine signaling, have been found to be associated with ASD in some cases. While detailed pathogenic mechanisms remain to be determined, the hypothesis that some cases of ASD may be influenced, or even caused, by maternal fetal brain-reactive antibodies or other in utero immune-related exposures is an active area of investigation. This article reviews the current literature in this area and proposes several directions for future research.

P wave indices, obesity, and the metabolic syndrome: the atherosclerosis risk in communities study

Atrial fibrillation and obesity are increasing in prevalence and are interrelated epidemics. There has been limited assessment of how obesity and the metabolic syndrome impact P wave indices, established electrocardiographic predictors of atrial fibrillation. We conducted a cross-sectional analysis to determine the association of obesity and the components of the metabolic syndrome with P wave indices in the population-based Atherosclerosis Risk in Communities (ARIC) study. Analyses were adjusted for demographic, anthropometric and clinical variables, and cardiovascular diseases and risk factors. Following relevant exclusions, 14,433 subjects were included (55% women and 24.7% black). In multivariable analyses, we identified significant, progressive increases in PR interval, P wave maximum duration, and P wave terminal force with BMI 25-30 kg/m(2) and BMI ≥30 kg/m(2) compared to the reference group <25 kg/m(2) (P < 0.0001 for trend for all P wave indices). These effects were present in both blacks and whites. Presence of metabolic syndrome was also associated with longer P wave indices. When components of the metabolic syndrome were examined separately, hypertension resulted in significant (P < 0.001) augmentation of the three P wave indices. Similarly, waist circumference was associated with greater P wave maximum duration in both races (P < 0.001). We concluded that P wave indices are significantly associated with obesity and particularly with hypertension and waist circumference. P wave indices may comprise intermediate markers, independent of age and cardiovascular risk, of the pathway linking obesity and with the risk of atrial fibrillation (AF).

Pattern specification and immune response transcriptional signatures of pericardial and subcutaneous adipose tissue

Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality in the United States. Recent studies suggest that pericardial adipose tissue (PCAT) secretes inflammatory factors that contribute to the development of CVD. To better characterize the role of PCAT in the pathogenesis of disease, we performed a large-scale unbiased analysis of the transcriptional differences between PCAT and subcutaneous adipose tissue, analysing 53 microarrays across 19 individuals. As it was unknown whether PCAT-secreted factors are produced by adipocytes or cells in the supporting stromal fraction, we also sought to identify differentially expressed genes in isolated pericardial adipocytes vs. isolated subcutaneous adipocytes. Using microarray analysis, we found that: 1) pericardial adipose tissue and isolated pericardial adipocytes both overexpress atherosclerosis-promoting chemokines and 2) pericardial and subcutaneous fat depots, as well as isolated pericardial adipocytes and subcutaneous adipocytes, express specific patterns of homeobox genes. In contrast, a core set of lipid processing genes showed no significant overlap with differentially expressed transcripts. These depot-specific homeobox signatures and transcriptional profiles strongly suggest different functional roles for the pericardial and subcutaneous adipose depots. Further characterization of these inter-depot differences should be a research priority.

The ECG vertigo in diabetes and cardiac autonomic neuropathy

The importance of diabetes in the epidemiology of cardiovascular diseases cannot be overemphasized. About one third of acute myocardial infarction patients have diabetes, and its prevalence is steadily increasing. The decrease in cardiac mortality in people with diabetes is lagging behind that of the general population. Cardiovascular disease is a broad term which includes any condition causing pathological changes in blood vessels, cardiac muscle or valves, and cardiac rhythm. The ECG offers a quick, noninvasive clinical and research screen for the early detection of cardiovascular disease in diabetes. In this paper, the clinical and research value of the ECG is readdressed in diabetes and in the presence of cardiac autonomic neuropathy.