Evaluation of Atrial Electromechanical Delay in Children with Obesity

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.

Impact of obesity on post-operative arrhythmias after congenital heart surgery in children and young adults

BACKGROUND

Obesity increases the risk of post-operative arrhythmias in adults undergoing cardiac surgery, but little is known regarding the impact of obesity on post-operative arrhythmias after CHD surgery.

METHODS

Patients undergoing CHD surgery from 2007 to 2019 were prospectively enrolled in the parent study. Telemetry was assessed daily, with documentation of all arrhythmias. Patients aged 2-20 years were categorised by body mass index percentile for age and sex (underweight <5, normal 5-85, overweight 85-95, and obese >95). Patients aged >20 years were categorised using absolute body mass index. We investigated the impact of body mass index category on arrhythmias using univariate and multivariate analysis.

RESULTS

There were 1250 operative cases: 12% underweight, 65% normal weight, 12% overweight, and 11% obese. Post-operative arrhythmias were observed in 38%. Body mass index was significantly higher in those with arrhythmias (18.8 versus 17.8, p = 0.003). There was a linear relationship between body mass index category and incidence of arrhythmias: underweight 33%, normal 38%, overweight 42%, and obese 45% (p = 0.017 for trend). In multivariate analysis, body mass index category was independently associated with post-operative arrhythmias (p = 0.021), with odds ratio 1.64 in obese patients as compared to normal-weight patients (p = 0.036). In addition, aortic cross-clamp time (OR 1.007, p = 0.002) and maximal vasoactive-inotropic score in the first 48 hours (OR 1.03, p = 0.04) were associated with post-operative arrhythmias.

CONCLUSION

Body mass index is independently associated with incidence of post-operative arrhythmias in children after CHD surgery.

Genetically predicted childhood obesity and adult atrial fibrillation: A mendelian randomization study

BACKGROUND AND AIMS

It is unclear whether the association of childhood obesity with adult atrial fibrillation observed in observational studies reflects causal effects. The aim of this study was to evaluate the association of childhood obesity with adult atrial fibrillation using genetic instruments.

METHODS AND RESULTS

We used a two-sample Mendelian randomization (MR) design to evaluate the association between childhood obesity and adult atrial fibrillation. Two sets of genetic variants (15 single nucleotide polymorphisms [SNPs] for childhood body mass index [BMI] and 12 SNPs for dichotomous childhood obesity) were selected as instruments. Summary data on SNP-childhood obesity and SNP-atrial fibrillation associations were obtained from recently published genome-wide association studies. Effect estimates were evaluated using inverse-variance weighted (IVW) methods. Other MR analyses, including MR-Egger, simple and weighted median, weighted MBE and MR-PRESSO methods were performed in sensitivity analyses. The IVW models showed that both a genetically predicted one-standard deviation increase in childhood BMI (kg/m²) and higher log-odds of childhood obesity were associated with a substantial increase in the risk of atrial fibrillation (OR = 1.22, 95% CI: 1.11-1.34, P < 0.001; OR = 1.09, 95% CI: 1.04-1.14, P < 0.001). MR-Egger regression showed no evidence of genetic pleiotropy for childhood BMI (intercept = 0.000, 95% CI: -0.024 to 0.023), but for childhood obesity (intercept = -0.036, 95% CI: -0.057 to -0.015). Similar results were observed using leave-one-out and other MR methods in sensitivity analyses.

CONCLUSIONS

This MR analysis found a consistent association between genetically predicted childhood obesity and an increased risk of adult atrial fibrillation. Further research is warranted to validate our findings.

Effects of metformin on epicardial adipose tissue and atrial electromechanical delay of obese children with insulin resistance

INTRODUCTION

Obesity is usually related to insulin resistance and glucose metabolism disorders. The relationship between insulin resistance and epicardial adipose tissue and atrial electromechanical delay has been described in previous studies.

AIM

This study aims to demonstrate the effects of metformin on epicardial adipose tissue and electromechanical delay in patients using metformin for insulin resistance.

MATERIALS AND METHODS

A total of 30 patients using metformin for insulin resistance were included in the study. Pre-treatment and post-treatment epicardial adipose tissue and electromechanical delay were evaluated.

RESULTS

There was a statistically significant decrease in epicardial adipose tissue thickness after 3 months of metformin therapy (6.4 ± 2.1 versus 4.7 ± 2.0; p = 0.008). Furthermore, the inter-atrial and intra-atrial electromechanical delay also significantly decreased after 3 months of metformin monotherapy (23.6 ± 8.2 versus 18.1 ± 5.8; p < 0.001, 9.1 ± 2.9 versus 6.3 ± 3.6; p = 0.003, respectively).

CONCLUSION

In this study, we show that metformin monotherapy significantly decreases epicardial adipose tissue thickness and electromechanical delay in obese children.