Obesity and Atrial Fibrillation: Epidemiology, Pathophysiology and Novel Therapeutic Opportunities

Temporal Trends in Outcomes of ST-Elevation Myocardial Infarction Patients With Heart Failure and Diabetes

Aims

We aimed to assess temporal trends in outcomes of ST-elevation myocardial infarction (STEMI) patients with diabetes and heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF) and compared both groups.

Methods

Data from the National Inpatient Sample was analyzed between 2005 and 2017. We assessed hospitalizations rate and in-hospital mortality, ventricular tachycardia (VT), ventricular fibrillation (VF), atrial fibrillation (AF), cardiogenic shock (CS), ischemic stroke, acute renal failure (ARF), and revascularization strategy. Socio-economic outcomes consisted of the length of stay (LoS) and total charges/stay.

Results

Hospitalization rate steadily decreased with time in STEMI patients with diabetes and HFrEF. Mean age (SD) decreased from 71 ± 12 to 67 ± 12 (p < 0.01), while the prevalence of comorbidities increased. Mortality was stable (around 9%). However, VT, VF, AF, CS, ischemic stroke, and ARF significantly increased with time. In STEMI patients with HFpEF and diabetes, the hospitalization rate significantly increased with time while mean age was stable. The prevalence of comorbidities increased, mortality remained stable (around 4%), but VF, ischemic stroke, and ARF increased with time. Compared to patients with HFrEF, HFpEF patients were 2 years older, more likely to be females, suffered from more cardio-metabolic risk factors, and had a higher prevalence of cardiovascular diseases. However, HFpEF patients were less likely to die [adjusted OR = 0.635 (0.601-0.670)] or develop VT [adjusted OR = 0.749 (0.703-0.797)], VF [adjusted OR = 0.866 (0.798-0.940)], ischemic stroke [adjusted OR = 0.871 [0.776-0.977)], and CS [adjusted OR = 0.549 (0.522-0.577)], but more likely to develop AF [adjusted OR = 1.121 (1.078-1.166)]. HFpEF patients were more likely to get PCI but less likely to get thrombolysis or CABG. Total charges per stay increased by at least 2-fold in both groups. There was a slight temporal reduction over the study period in the LoS of the HFpEF.

Conclusion

While hospitalizations for STEMI in patients with diabetes and HFpEF followed an upward trend, we observed a temporal decrease in those with HFrEF. Mortality was unchanged in both HF groups despite the temporal increase in risk factors. Nevertheless, HFpEF patients had lower in-hospital mortality and cardiovascular events, except for AF.

The Risk of Atrial Fibrillation Increases with Earlier Onset of Obesity: A Mendelian Randomization Study

Background: Obesity is a well-established risk factor for atrial fibrillation (AF). Previous epidemiological research on obesity and AF often focused on adult populations and now broadened to earlier in life. Therefore, this study aimed to determine the relationships between obesity at different periods of life and the risk of AF. Methods: A two-sample Mendelian randomization (MR) study design using summarised data from 6 genome-wide association studies (GWASs) was employed in this study. Single nucleotide polymorphisms (SNPs) associated with adult obesity, childhood obesity, childhood body mass index (BMI), waist-to-hip ratio adjusted for BMI (WHRadjBMI), birth weight and AF were independently retrieved from large-scale GWASs. For SNP identification, the genome-wide significance threshold was set at p <5.00×10^-8. To obtain causal estimates, MR analysis was conducted using the inverse variance-weighted (IVW) method. The weighted median, MR-Egger methods and MR-robust adjusted profile score (MR-RAPS) were used to evaluate the robustness of MR analysis. Results: A total of 204 SNPs were identified as the genetic instrumental variables (5 SNPs for childhood obesity, 13 SNPs for childhood BMI, 137 SNPs for birth weight, 35 SNPs for adult WHRadjBMI, and 14 SNPs for adult obesity). The results of MR analysis demonstrated that the genetically predicted adult obesity, childhood BMI, and birth weight were associated with AF risk. Notably, a 1 unit standard deviation (1-SD) increase in adult obesity was related to a 13% increased risk of AF [p=6.51×10^-7, OR, 1.13 (95% CI, 1.08-1.19)], a 1-SD increase in childhood BMI was related to a 18% increased risk of AF [p=1.77×10^-4, OR, 1.18 (95% CI, 1.08-1.29)], and a 1-SD increase in birth weight was related to a 26% increased risk of AF [p=1.27×10^-7, OR, 1.26 (95% CI, 1.16-1.37)]. There was no evidence of pleiotropy or heterogeneity between the MR estimates obtained from multiple SNPs. Conclusion: Our study reveals the association of genetic susceptibility to obesity with a higher risk of AF. Moreover, an earlier age at obesity was associated with an increased risk of AF. Therefore, public awareness of the dangers of obesity and active early weight control may prevent the development of AF.

Enhancing Fatty Acids Oxidation via L-Carnitine Attenuates Obesity-Related Atrial Fibrillation and Structural Remodeling by Activating AMPK Signaling and Alleviating Cardiac Lipotoxicity

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in clinical setting. Its pathogenesis was associated with metabolic disorder, especially defective fatty acids oxidation (FAO). However, whether promoting FAO could prevent AF occurrence and development remains elusive. In this study, we established a mouse model of obesity-related AF through high-fat diet (HFD) feeding, and used l-carnitine (LCA, 150 mg/kg⋅BW/d), an endogenous cofactor of carnitine palmitoyl-transferase-1B (CPT1B; the rate-limiting enzyme of FAO) to investigate whether FAO promotion can attenuate the AF susceptibility in obesity. All mice underwent electrophysiological assessment for atrial vulnerability, and echocardiography, histology and molecular evaluation for AF substrates and underlying mechanisms, which were further validated by pharmacological experiments in vitro. HFD-induced obese mice increased AF vulnerability and exhibited apparent atrial structural remodeling, including left atrial dilation, cardiomyocyte hypertrophy, connexin-43 remodeling and fibrosis. Pathologically, HFD apparently leads to defective cardiac FAO and subsequent lipotoxicity, thereby evoking a set of pathological reactions including oxidative stress, DNA damage, inflammation, and insulin resistance. Enhancing FAO via LCA attenuated lipotoxicity and lipotoxicity-induced pathological changes in the atria of obese mice, resulting in restored structural remodeling and ameliorated AF susceptibility. Mechanistically, LCA activated AMPK/PGC1α signaling both in vivo and in vitro, and pharmacological inhibition of AMPK via Compound C attenuated LCA-induced cardio-protection in palmitate-treated primary atrial cardiomyocytes. Taken together, our results demonstrated that FAO promotion via LCA attenuated obesity-mediated AF and structural remodeling by activating AMPK signaling and alleviating atrial lipotoxicity. Thus, enhancing FAO may be a potential therapeutic target for AF.

Anti-Xa Levels in Morbidly Obese Patients Using Apixaban or Rivaroxaban, Before and After Bariatric Surgery

BACKGROUND

Despite limited evidence about the efficacy and safety of anticoagulation in patients post bariatric surgery, both vitamin K antagonists (VKA) and direct-acting oral anticoagulants (DOACs) are commonly prescribed.

AIM

To evaluate plasma anti-Xa levels of DOACs in morbidly obese (MO) patients before and after a Roux-en-Y gastric bypass (RYGB) procedure.

PATIENTS AND METHODS

Retrospective, cross-sectional, and longitudinal study of anti-Xa activity of apixaban or rivaroxaban in MO patients (N = 41).

RESULTS

Preoperative analysis of plasma anti-Xa levels were within the normal range in patients using apixaban (n = 29; body mass index [BMI] 44.5 ± 5.1 kg/m²) as well as those using rivaroxaban (n = 12; BMI 42.6 ± 5.9 kg/m²). Postoperative anti-Xa levels of apixaban were all within the therapeutic range, whereas anti-Xa levels of rivaroxaban were subtherapeutic in nine out of 14 (64%) patients. Perioperative longitudinal follow-up in patients using apixaban (n = 18) showed no significant change in anti-Xa levels after RYGB.

CONCLUSION

Plasma anti-Xa levels of apixaban in MO patients remained within the therapeutic range up to a body weight of 144 kg. In patients using rivaroxaban, no statistically significant relation between anti-Xa levels and bodyweight was found. After RYGB, plasma anti-Xa levels of apixaban were unaffected, whereas plasma anti-Xa levels of rivaroxaban tended to become subtherapeutic.

Effectiveness of Direct Oral Anticoagulants in Obese Adults With Atrial Fibrillation: A Systematic Review of Systematic Reviews and Meta-Analysis

Background: Atrial Fibrillation (AF) is the most common sustained cardiac arrhythmia. Obesity is an independent risk factor for AF. Anticoagulants have been strongly recommended by all international guidelines to prevent stroke. However, altered pathophysiology in obese adults may influence anticoagulant pharmacology. Direct oral anticoagulants (DOACs) in the context of obesity and AF have been examined in recent systematic reviews. Despite the similarities in included studies, their results and conclusions do not agree.

Methods and Results: The protocol for this review was registered with PROSPERO (CRD42020181510). Seven key electronic databases were searched using search terms such as “atrial fibrillation,” “obese,^*” “overweight,” “novel oral anticoagulant,” “direct oral anticoagulant,” “DOAC,” “NOAC,” “apixaban,” dabigatran,” “rivaroxaban,” and “edoxaban” to locate published and unpublished studies. Only systematic reviews with meta-analyses that examined the effect of DOACs in overweight or obese adults with AF, published in the English language, were included. A total of 9,547 articles were initially retrieved. After removing the duplicates, title and abstract review and full-text review, five articles were included in the systematic review. From these only RCTs were included in the meta-analyses. There was disagreement within the published systematic reviews on DOACs in obesity. The results from our meta-analysis did not show any significant difference between all body mass index (BMI) groups for all outcomes at both 12 months and for the entire trial duration. Non-significant differences were seen among the different types of DOACs.

Conclusion: There was no difference between the BMI classes in any of the outcomes assessed. This may be due to the limited number of people in the trial that were in the obese class, especially obese class III. There is a need for large prospective trials to confirm which DOACs are safe and efficacious in the obese class III adults and at which dose.

Economic burden of rivaroxaban and warfarin among nonvalvular atrial fibrillation patients with obesity and polypharmacy

Aim: Evaluate healthcare resource utilization (HRU) and costs associated with rivaroxaban and warfarin among nonvalvular atrial fibrillation (NVAF) patients with obesity and polypharmacy. Materials & methods: IQVIA PharMetrics^® Plus (January 2010-September 2019) data were used to identify NVAF patients with obesity (BMI ≥30 kg/m²) and polypharmacy (≥5 medications) initiated on rivaroxaban or warfarin. Weighted rate ratios and cost differences were evaluated post-treatment initiation. Results: Rivaroxaban was associated with significantly lower rates of HRU, including hospitalization (rate ratio [95% CI]: 0.83 [0.77, 0.92]). Medical costs were reduced in rivaroxaban users (difference [95% CI]: -US$6868 [-US$10,628, -US$2954]), resulting in significantly lower total healthcare costs compared with warfarin users (difference [95% CI]: -US$4433 [-US$8136, -US$582]). Conclusion: Rivaroxaban was associated with lower HRU and costs compared with warfarin among NVAF patients with obesity and polypharmacy in commercially insured US patients.

The Impact of Obesity in Critical Illness

The prevalence of obesity is rising worldwide. Adipose tissue exerts anatomic and physiological effects with significant implications for critical illness. Changes in respiratory mechanics cause expiratory flow limitation, atelectasis, and V̇/Q̇ mismatch with resultant hypoxemia. Altered work of breathing and obesity hypoventilation syndrome may cause hypercapnia. Challenging mask ventilation and peri-intubation hypoxemia may complicate intubation. Patients with obesity are at increased risk of ARDS and should receive lung-protective ventilation based on predicted body weight. Increased positive end expiratory pressure (PEEP), coupled with appropriate patient positioning, may overcome the alveolar decruitment and intrinsic PEEP caused by elevated baseline pleural pressure; however, evidence is insufficient regarding the impact of high PEEP strategies on outcomes. Venovenous extracorporeal membrane oxygenation may be safely performed in patients with obesity. Fluid management should account for increased prevalence of chronic heart and kidney disease, expanded blood volume, and elevated acute kidney injury risk. Medication pharmacodynamics and pharmacokinetics may be altered by hydrophobic drug distribution to adipose depots and comorbid liver or kidney disease. Obesity is associated with increased risk of VTE and infection; appropriate dosing of prophylactic anticoagulation and early removal of indwelling catheters may decrease these risks. Obesity is associated with improved critical illness survival in some studies. It is unclear whether this reflects a protective effect or limitations inherent to observational research. Obesity is associated with increased risk of intubation and death in SARS-CoV-2 infection. Ongoing molecular studies of adipose tissue may deepen our understanding of how obesity impacts critical illness pathophysiology.

Plasma Cortisol and Risk of Atrial Fibrillation: A Mendelian Randomization Study

CONTEXT

Atrial fibrillation (AF), cardiac arrhythmias, and related risk factors are common in patients with Cushing's syndrome, or clinical chronic hypercortisolism. While hypercortisolism may be associated with AF, this association has not yet been ascertained causally.

OBJECTIVE

To determine whether plasma cortisol is causally associated with AF using a 2-sample Mendelian randomization (MR) design.

METHODS

Three genetic variants in the SERPINA1/SERPINA6 locus and functionally associated with plasma cortisol were identified in the CORtisol NETwork consortium (12 597 participants). Summary-level genome-wide association study (GWAS) data for the associations between the cortisol-associated variants and AF were obtained from a GWAS meta-analysis of 6 studies (60 620 AF cases and 970 216 noncases) and the FinnGen consortium (17 325 AF cases and 97 214 noncases). The fixed-effects inverse-variance weighted approach accounting for genetic correlations between variants was used for analysis. Multivariable MR analyses were conducted to assess potential mediating effects of systolic blood pressure (SBP) and waist circumference (WC). Summary-level GWAS data for SBP and WC were obtained respectively from the International Consortium of Blood Pressure (757 601 participants) and the Genetic Investigation of ANthropometric Traits consortium (232 101 participants).

RESULTS

One standard deviation increase in genetically predicted plasma cortisol was associated with greater risk of AF (odds ratio [OR] 1.20, 95% CI 1.06-1.35). The association attenuated when adjusting for genetically predicted SBP and WC (OR 0.99, 95% CI 0.72-1.38).

CONCLUSION

Evidence derived from the MR study suggests a positive association between plasma cortisol and risk of AF, likely mediated through SBP and WC.

Interaction effect of myocardial infarction and obesity on left atrial functions

PURPOSE

To determine whether myocardial infarction (MI) would lead to a greater decrease in left atrial (LA) functions in subjects with than without obesity.

METHODS

A total of 310 consecutive patients were divided into four groups according to the presence or absence of obesity and MI. The functions of the LA were evaluated in terms of longitudinal deformation of the LA myocardium via 2D speckle-tracking echocardiography.

RESULTS

The adjusted analysis showed a reduction in the strain and strain rate during the reservoir and contraction phases and in the strain rate during the conduit phase in patients with MI and in subjects with obesity (P < .05). In addition, there was a significant interaction effect of obesity and MI on the strain rate during the contraction phase (P = .048).

CONCLUSIONS

There is an independent and additional interaction effect of obesity and MI on the reservoir and conduit functions of the LA. MI was more deleterious to the contraction function in subjects without than with obesity, so that the contraction function was similar in MI patients without obesity and MI patients with obesity.

Real-world effectiveness and safety of rivaroxaban versus warfarin among non-valvular atrial fibrillation patients with obesity in a US population

OBJECTIVES

Current evidence indicates that the pharmacokinetic profile of rivaroxaban is not significantly impacted by body weight. However, real-world data are needed to better assess the potential clinical benefits and risks associated with rivaroxaban in non-valvular atrial fibrillation (NVAF) patients with obesity. Thus, our objectives were to assess the real-world effectiveness and safety of rivaroxaban versus warfarin among NVAF patients with obesity in the US nationally representative commercially-insured population.

METHODS

Health insurance claims data from the IQVIA PharMetrics Plus database (January 2010-September 2019) were used to identify NVAF patients with obesity (based on diagnosis codes) initiated on rivaroxaban or warfarin. Inverse probability of treatment weighting (IPTW) was used to adjust for imbalances between groups. Study outcomes of interest were evaluated up to 36 months post-treatment initiation and included the composite of stroke or systemic embolism (stroke/SE) and major bleeding. Outcomes were compared using Cox proportional hazards regression models with hazard ratios (HR) and 95% confidence intervals (CIs).

RESULTS

A total of 10,555 patients were initiated on rivaroxaban and 5080 patients on warfarin. Following IPTW, the risk of stroke/SE was 26% lower among patients prescribed rivaroxaban relative to warfarin (HR: 0.74, 95% CI: 0.60, 0.91, p = .004) at 36 months. Rivaroxaban-initiated patients had a risk of major bleeding similar to that of warfarin-initiated patients (HR: 0.85, 95% CI: 0.71, 1.02, p = .085).

CONCLUSIONS

These results suggest that rivaroxaban is an effective and safe treatment option among NVAF patients with obesity in a commercially-insured US population.

The Influence of Obesity on the Association of Obstructive Sleep Apnea and Atrial Fibrillation

BACKGROUND AND OBJECTIVE

The association between obstructive sleep apnea (OSA) and atrial fibrillation (AF) has been closely studied. However, obesity is a powerful confounder in the causal relationship between OSA and cardiovascular disease. The contribution of obesity in the relationship between OSA and AF remains unclear.

METHODS

We recruited 457 consecutive patients equally with and without AF who underwent clinically indicated diagnostic polysomnography at a single academic sleep center. Multivariable logistic regression adjusting for age, sex, hypertension, and heart failure was performed to study the independent association between OSA and AF stratified by obesity.

RESULTS

A total of 457 patients (male: 56.2%, mean age 63.1 ± 13.3 years) was included. OSA prevalence was similar between those with and without AF (52.6% vs. 47.4%, respectively; p = 0.24). In multivariable analysis, no association was found between AF and OSA regardless of obesity status. When severe OSA (vs. non-severe OSA) was modeled as a dependent variable, AF was associated with a higher likelihood of severe OSA in non-obese patients [odds ratio (OR): 2.29, 95% confidence interval (CI): 1.23-4.35, p = 0.01], but not in obese patients (OR: 0.95, 95% CI: 0.48-1.90, p = 0.89).

CONCLUSION

The association of OSA with AF was present only in the non-obese and was limited to severe OSA patients. In contrast, no association was found in obese patients. The association between OSA and AF is partly dependent on the body habitus.

The Pharmacology, Efficacy, and Safety of Rivaroxaban in Obese Patient Populations

Cardiovascular disease (CVD) remains the leading cause of death in the USA. Several risk factors have been identified, and obesity has become one of prominent concern. Excessive weight is considered a risk factor for CVD based on evidence linking it to a hypercoagulable state. Considering the prevalence of CVD and obesity in the USA, along with the increased risk for thrombus-related events, anticoagulation plays a significant role in prevention and treatment. Direct oral anticoagulants have taken the place of many traditional anticoagulants. Considering the recently approved indications and continued postmarketing studies conducted with rivaroxaban, this updated review provides data on the overall impact of obesity on this compound. This includes data obtained from both healthy obese volunteers and obese patients with various CVD conditions enrolled in rivaroxaban clinical trials, along with data obtained from postmarketing real-world evidence studies. Assessment of the clinical pharmacology and population pharmacokinetics in obese individuals revealed no clinically relevant effects of increased weight. Additionally, subgroup analyses from each of the pivotal phase III trials supporting the current approved labeling also demonstrated consistent efficacy and safety results in obese patients. Lastly, these findings are further supported by several recent real-world evidence studies assessing the continued effectiveness and safety of rivaroxaban. In conclusion, rivaroxaban's overall pharmacological and clinical profile remained consistent in obese adults when assessed in both drug development and postmarketing studies, supporting the premise that higher weight does not necessitate adjustment in either dose strength or regimen.

Direct Oral Anticoagulant Use in Special Populations: Elderly, Obesity, and Renal Failure

PURPOSE OF REVIEW

The purpose of this review is to examine the safety and effectiveness of direct oral anticoagulants and provide recommendations for the treatment of venous thromboembolism and atrial fibrillation in obese patients, elderly patients, and patients with chronic kidney disease.

RECENT FINDINGS

Multiple retrospective cohort studies have shown no difference in bleeding, stroke, or venous thromboembolism outcomes between DOACs and warfarin in patients who are obese, elderly, or those with chronic kidney disease or on dialysis. Some studies have shown that DOACs have a lower bleeding risk than warfarin in these populations. DOACs may be a safe and effective alternative to warfarin for the prevention of stroke in atrial fibrillation patients who are obese, elderly, or those with chronic kidney disease or on dialysis. Apixaban may improve clinical outcomes by lowering the risk of bleeding versus warfarin. DOACs may also be an effective and safe alternative to warfarin for the treatment of venous thromboembolism in obese patients; however, additional studies are needed to assess their use in elderly patients and those with CKD.

The Impact of Body Weight and Renal Function on the Risk of Bleeding With Direct Oral Anticoagulants in Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) increases the risk of stroke and direct oral anticoagulants (DOACs) are first-line agents for prevention. Gaps in the literature cause reluctance in prescribing DOACs for patients with renal dysfunction and/or extremes in body weight.

OBJECTIVE

To evaluate the impact body weight and renal function have on major and clinically relevant nonmajor (CRNM) bleeding events and ischemic strokes in AF patients receiving a DOAC.

METHODS

This retrospective cohort study included adults with nonvalvular atrial fibrillation (NVAF) or atrial flutter (AFL) receiving a DOAC ≥12 months. The primary outcome was a composite of major and CRNM bleeding events. Secondary outcomes included ischemic stroke and risk factors for bleeding events.

RESULTS

Of the 233 patients analyzed, 25 patients experienced a bleeding event. Patients who bled weighed 10 kg less (P = 0.043) than those who did not and had a higher HASBLED score (P = 0.003). Multivariate logistic regression identified weight (P = 0.048), serum creatinine (SCr; P = 0.027), and HASBLED score (P = 0.024) as the significant predictors for experiencing a bleed. Three patients experienced a stroke.

CONCLUSION AND RELEVANCE

This study demonstrates an association between higher baseline SCr, elevated HASBLED score, and lower weight, with an increased risk of bleeding in patients with NVAF or AFL receiving a DOAC. These findings add to prescribing considerations when initiating DOACs. Closer monitoring is advised for patients with significant renal dysfunction and/or low body weight, even with renal dose adjustments.

Paroxysmal atrial fibrillation associated with a moderate form of COVID-19 in a middle-aged man with low cardiovascular risk factor: More still needs to be done in this topic

Strict monitoring of the heart rhythm in patients with COVID‐19 even nonsevere case and patient with low cardiovascular risk factors is very important to prevent fatal outcomes.

Circadian Mechanisms: Cardiac Ion Channel Remodeling and Arrhythmias

Circadian rhythms are involved in many physiological and pathological processes in different tissues, including the heart. Circadian rhythms play a critical role in adverse cardiac function with implications for heart failure and sudden cardiac death, highlighting a significant contribution of circadian mechanisms to normal sinus rhythm in health and disease. Cardiac arrhythmias are a leading cause of morbidity and mortality in patients with heart failure and likely cause ∼250,000 deaths annually in the United States alone; however, the molecular mechanisms are poorly understood. This suggests the need to improve our current understanding of the underlying molecular mechanisms that increase vulnerability to arrhythmias. Obesity and its associated pathologies, including diabetes, have emerged as dangerous disease conditions that predispose to adverse cardiac electrical remodeling leading to fatal arrhythmias. The increasing epidemic of obesity and diabetes suggests vulnerability to arrhythmias will remain high in patients. An important objective would be to identify novel and unappreciated cellular mechanisms or signaling pathways that modulate obesity and/or diabetes. In this review we discuss circadian rhythms control of metabolic and environmental cues, cardiac ion channels, and mechanisms that predispose to supraventricular and ventricular arrhythmias including hormonal signaling and the autonomic nervous system, and how understanding their functional interplay may help to inform the development and optimization of effective clinical and therapeutic interventions with implications for chronotherapy.

Phospho-ablation of cardiac sodium channel Nav1.5 mitigates susceptibility to atrial fibrillation and improves glucose homeostasis under conditions of diet-induced obesity

BACKGROUND

Atrial fibrillation (AF) is the most common sustained arrhythmia, with growing evidence identifying obesity as an important risk factor for the development of AF. Although defective atrial myocyte excitability due to stress-induced remodeling of ion channels is commonly observed in the setting of AF, little is known about the mechanistic link between obesity and AF. Recent studies have identified increased cardiac late sodium current (I_Na,L) downstream of calmodulin-dependent kinase II (CaMKII) activation as an important driver of AF susceptibility.

METHODS

Here, we investigated a possible role for CaMKII-dependent I_Na,L in obesity-induced AF using wild-type (WT) and whole-body knock-in mice that ablates phosphorylation of the Na_v1.5 sodium channel and prevents augmentation of the late sodium current (S571A; SA mice).

RESULTS

A high-fat diet (HFD) increased susceptibility to arrhythmias in WT mice, while SA mice were protected from this effect. Unexpectedly, SA mice had improved glucose homeostasis and decreased body weight compared to WT mice. However, SA mice also had reduced food consumption compared to WT mice. Controlling for food consumption through pair feeding of WT and SA mice abrogated differences in weight gain and AF inducibility, but not atrial fibrosis, premature atrial contractions or metabolic capacity.

CONCLUSIONS

These data demonstrate a novel role for CaMKII-dependent regulation of Na_v1.5 in mediating susceptibility to arrhythmias and whole-body metabolism under conditions of diet-induced obesity.

A Stronger Association of Epicardial Fat Volume with Non-Valvular Atrial Fibrillation Than Measures of General Obesity in Chinese Patients Undergoing Computed Tomography Coronary Angiography

OBJECTIVE

An association of atrial fibrillation (AF) with epicardial fat volume (EFV) varied in different ethnic groups. We evaluated the AF-related risk factors and its association with pericardial fat in Chinese patients.

METHODS

Patients referred for coronary computed tomography angiography (CCTA) in Shanghai East Hospital during 2012 to 2014 (n=2042, 43.8% women, mean age 65.0 years) had AF and cardiovascular risk assessment. Pericardial fat depots were measured from CT and the association of EFV with non-valvular AF risk factors was evaluated by multivariate logistic regression models.

RESULTS

AF was present in 8.5% of patients with 11.6% of AF patients having rheumatic heart disease (RHD) and 8.7% having other valvular diseases. With increasing age, the proportion of RHD-related AF decreased and the risk factors for non-valvular AF increased. There was a significantly higher proportion of risk factors for non-valvular AF in men than in women (p=0.008), but RHD-related AF was more prevalent in women than men (p=0.013). The patients with non-valvular AF had significantly higher BMI and EFV with more pronounced elevation of EFV (p<0.001). Multivariate logistic regression showed a significant association of EFV with AF after adjustment for BMI and clinical risk factors, and the highest EFV quartile was associated with AF independent of left atrial size and obstructive coronary artery disease.

CONCLUSION

The association of EFV with non-valvular AF in Chinese patients was independent of generalized adiposity and clinical risk factors especially in highest EFV quartile. These findings support the growing appreciation of the association of EFV with AF.

Race, Body Mass Index, and the Risk of Atrial Fibrillation: The Multi-Ethnic Study of Atherosclerosis

Background

Higher body mass index (BMI) is associated with increased risk of incident atrial fibrillation (AF), but it is not known whether this relationship varies by race/ethnicity.

Methods and Results

Eligible participants (6739) from MESA (Multi‐Ethnic Study of Atherosclerosis) were surveilled for incident AF using MESA hospital surveillance, scheduled MESA study ECG, and Medicare claims data. After a median 13.8 years of follow‐up, 970 participants (14.4%) had incident AF. With BMI modeled categorically in a Cox proportional hazards model, only those with grade II and grade III obesity had increased risks of AF (hazard ratio [HR], 1.50; 95% CI, 1.14–1.98, P=0.004 for grade II obesity and HR, 2.13; 95% CI, 1.48–3.05, P<0.0001 for grade III obesity). The relationship between BMI and AF risk was J‐shaped. However, the risk of AF as a function of BMI varied substantially by race/ethnicity (P value for interaction=0.02), with Chinese‐American participants having a much higher risk of AF with higher BMI and Black participants having minimal increased risk of AF with higher BMI.

Conclusions

Obesity is associated with an increased risk of incident AF, but the relationship between BMI and the risk of AF is J‐shaped and this relationship differs by race/ethnicity, such that Chinese‐American participants have a more pronounced increased risk of AF with higher BMI, while Black participants have minimal increased risk. Further exploration of the differential effects of BMI by race/ethnicity on cardiovascular outcomes is needed.

Cryoablation for pulmonary veins isolation in obese patients with atrial fibrillation compared to nonobese patients

BACKGROUND

Pulmonary veins isolation (PVI) by cryoballoon (CB) ablation is marginally represented in clinical studies in obese patients. The aim of this analysis was to evaluate the safety and efficacy of CB-PVI in a large cohort of overweight and obese patients from the 1STOP project.

METHODS

From 2012 to 2018, 2048 patients with atrial fibrillation (AF) (70% male, 59 ± 11 years; 75% paroxysmal AF) underwent index CB-PVI. The patient data were separated into three cohorts for statistical evaluation, including: normal weight (body mass index [BMI] < 25 kg/m² ), overweight (BMI = 25-30 kg/m² ), and obese patients (BMI > 30 kg/m² ).

RESULTS

Out of 2048 patients, 693 (34%) patients had a BMI < 25 and were deemed as normal. There were 944 (46%) patients categorized as overweight (BMI = 25-30) and 411 (20%) as obese (BMI > 30). Overweight or obese patients were more often in persistent AF, had more frequently hypertension and diabetes, had higher CHA₂ DS₂ -VASc score, and had a number of failed antiarrhythmic drug (AAD). Periprocedural complication rates were similar among the three cohorts. The 12-month freedom from AF recurrence was 76.4% in the normal BMI group as compared to 79.2% in the overweight and 73.5% in the obese group (p = .35). However, 48% of overweight patients were on AAD treatment during the follow-up. By multivariate analysis, BMI was not a predictor for AF recurrence following the index CB-PVI.

CONCLUSION

CB-PVI in obese patients is a safe procedure. Increased BMI (either moderate or severe) does not seem to be associated with a worse outcome or to a different rate of AAD discontinuation at 12 months.

A Review of Obesity, Physical Activity, and Cardiovascular Disease

PURPOSE OF REVIEW

The focus of this review is to discuss obesity, physical activity (and physical inactivity/sedentary behavior), cardiovascular disease (CVD), and their often interrelated health implications. The authors summarize the pathophysiological changes associated with obesity, which lead to the development of CVD, recommendations for interventions such as diet, increased physical activity, and weight loss according to current literature and guidelines, and the critical importance of cardiorespiratory fitness (CRF).

RECENT FINDINGS

Clinical trials continue to demonstrate improved outcomes among overweight or obese individuals who achieve a healthy weight using various methods. Increasing CRF levels appears to demonstrate the largest health improvements, regardless of underlying comorbidities or achieving weight loss. CRF, which is perhaps the single most important predictor of overall health, seems more important than weight loss alone regarding improved CVD outcomes in the obese population. These findings are reproduced in studies involving patients with various forms of CVD and CVD risk factors. The importance of CRF is well established; future endeavors to establish specific CRF targets for various patient cohorts are needed.

Body Mass Index, Sex, and Incident Atrial Fibrillation in Diabetes: The ACCORD Trial

OBJECTIVES

This study sought to characterize the relationship between obesity and the risk of atrial fibrillation (AF) in diabetes.

BACKGROUND

Obesity is associated with increased risk of AF in the general population, but there is evidence that this relationship may differ in those with diabetes.

METHODS

Cox proportional hazards models were used to examine the association between body mass index (BMI) and incident AF on study electrocardiogram in participants from the ACCORD (Action to Control Cardiovascular Risk in Diabetes) trial.

RESULTS

Among 10,074 ACCORD participants (age 62.7 ± 6.6 years, 38.7% women, 62.2% white), 8.4% were normal weight, 29.0% were overweight, 53.1% were obese, and 9.5% were severely obese. Participants with obesity and severe obesity had increased risks of AF compared with normal weight (hazard ratio [HR]: 1.91; 95% confidence interval [CI]: 1.03 to 3.93; and HR: 3.69; 95% CI: 1.79 to 8.22, respectively). There was a 51% increased risk of AF per SD (5.4 U) BMI increase. However, there was a sex and BMI interaction-in men, obesity and severe obesity were associated with a substantially increased AF risk (HR: 3.19; 95% CI: 1.27 to 7.31; and HR: 4.79; 95% CI: 2.11 to 11.93, respectively), whereas there was no statistically significant association in women.

CONCLUSIONS

In those with diabetes, obesity and severe obesity are associated with increased risk of AF, but there is an interaction between sex and BMI, such that elevated BMI appears to confer a much greater risk of AF in men than in women. Further studies exploring the differential effects of BMI on AF risk in men and women are needed.

Left atrial strain and diastolic function abnormalities in obese and type 2 diabetic adolescents and young adults

Background

Adults with obesity and type 2 diabetes mellitus (T2DM) related to obesity are at increased risk of heart failure with preserved ejection fraction (HFpEF). Whether left ventricular (LV) diastolic function abnormalities related to obesity and T2DM start in adolescence and early adulthood is unknown. We non-invasively evaluated the differences seen in LV diastolic and left atrial (LA) function in adolescents and young adults with obesity and T2DM.

Methods

We analyzed echocardiographic measures of LV diastolic function in patients with structurally normal hearts which were divided into 3 groups (normal weight, obese, and T2DM). Spectral and tissue Doppler and 2-D speckle tracking measurements of diastolic function were obtained. Logistic regression was performed to compare the prevalence of abnormalities in diastolic function based on the worst 25th percentile for each measure to determine the prevalence of diastolic and LA function abnormalities in obese and T2DM patients.

Results

331 teenagers and young adults (median age 22.1 years) were analyzed (101 normal weight, 114 obese, 116 T2DM). Obese and T2DM group had lower E/A and higher E/e′. Obese and T2DM patients had significantly lower atrial reservoir, conduit, and booster strain and worse reservoir and conduit strain rate compared to normal patients (p < 0.001 for all measures). All patients had normal LA volumes. On multivariable analysis, conduit strain and reservoir and conduit strain rate were independently associated with having below the 25th percentile e′. Conduit strain rate was independently associated with having below the 25th percentile for mitral E/A ratio on multivariable analysis.

Conclusions

Abnormal indices of LV diastolic function are detected in adolescents and young adults with obesity and T2DM. LA function and strain analysis were able to detect evidence of decreased reservoir, conduit, and booster strain in these patients although LA volume was normal. The use of LA function strain may increase our ability to detect early diastolic function abnormalities in this population.

Effectiveness and safety of rivaroxaban versus warfarin in obese nonvalvular atrial fibrillation patients: analysis of electronic health record data

Background: Although rivaroxaban has demonstrated consistent drug levels in normal weight and obese patients, sufficient confirmation of equal clinical effectiveness and safety is currently lacking.Purpose: To evaluate the effectiveness and safety of rivaroxaban versus warfarin for prevention of stroke and systemic embolism (SSE) in obese nonvalvular atrial fibrillation (NVAF) patients.Methods: Using Optum de-identified Electronic Health Record (EHR) data from November 2011 to September 2018,we evaluated NVAF patients with a body mass index (BMI)≥30 kg/m² newly initiated on rivaroxaban or warfarin (index date), with ≥12-months of EHR activity and ≥1 encounter before the index date. We excluded patients with valvular disease or evidence of oral anticoagulant (OAC) use at baseline. Patients who were prescribed rivaroxaban were 1:1 propensity-score matched to patients who were prescribed warfarin (standard differences <0.10 achieved for all covariates). Outcomes included SSE and major bleeding using an intent-to-treat approach. Subanalyses stratified by BMI (30.0-34.9, 35.0-39.9 and ≥40 kg/m²) were performed. Cox regression was performed and reported as hazard ratios (HRs) and 95% confidence intervals (CIs).Results: We included 35,613 rivaroxaban and 35,613 warfarin users with NVAF. Patients were followed for a median of 2.6 years (25%-75% range = 1.2-4.1). Rivaroxaban was associated with a reduced risk of SSE (HR = 0.83, 95%CI = 0.73-0.94) and major bleeding (HR = 0.82, 95%CI = 0.75-0.89) compared to warfarin. Subanalysis did not show a statistically significant interaction across BMI categories for SSE (p-interaction = .58) or major bleeding (p-interaction = .44) outcomes.Conclusions: Among obese NVAF patients, prescription of rivaroxaban was associated with a reduced risk of SSE and major bleeding compared to warfarin, which remained consistent across BMI classes.

Leptin improves intestinal flora dysfunction in mice with high-fat diet-induced obesity

OBJECTIVE

This study investigated the effects of leptin on intestinal flora and inflammation in mice with high-fat diet (HFD)-induced obesity.

METHODS

Mice were fed an HFD for 8 weeks; some were concurrently administered oral leptin for 4 weeks. Pathological changes in adipose tissue were detected using hematoxylin-eosin staining; endotoxin content in adipose tissue was measured by enzyme-linked immunosorbent assay. Intestinal flora were characterized by 16S bacterial rDNA sequencing. Levels of Toll-like receptor 4 (TLR4), nuclear factor-κB inhibitor α (IκB-α), and phosphorylated c-Jun N-terminal kinase (p-JNK) were detected by western blotting.

RESULTS

Mice in the HFD group exhibited weight gain, elevated endotoxin content, and adipocyte hypertrophy, compared with the non-obese control group. Moreover, abundance of bacteria in the Bacteroides genus and community diversity were both reduced in the HFD group; reductions also were observed at corresponding phylum, class, and order levels. Levels of TLR4, IκB-α, and p-JNK were also elevated in the HFD group. Compared with the model group, leptin administration reduced the weight gain and endotoxin content, while increasing Bacteroides abundance and community diversity; it also reduced the levels of TLR4, IκB-α, and p-JNK.

CONCLUSION

Leptin administration improved intestinal flora dysfunction and inflammation in mice with HFD-induced obesity.

Effectiveness and Safety of Oral Anticoagulants among NVAF Patients with Obesity: Insights from the ARISTOPHANES Study

This ARISTOPHANES analysis examined stroke/systemic embolism (SE) and major bleeding (MB) among a subgroup of nonvalvular atrial fibrillation (NVAF) patients with obesity prescribed warfarin or non-vitamin K antagonist oral anticoagulants (NOACs) in order to inform clinical decision making. A retrospective observational study was conducted among NVAF patients who were obese and initiated apixaban, dabigatran, rivaroxaban, or warfarin from 1 January 2013–30 September 2015, with data pooled from CMS Medicare and four US commercial claims databases. Propensity score matching was completed between NOACs and against warfarin in each database, and the results were pooled. Cox models were used to evaluate the risks of stroke/SE and MB. A total of 88,461 patients with obesity were included in the study. Apixaban and rivaroxaban were associated with a lower risk of stroke/SE vs. warfarin (HR: 0.63, 95% CI: 0.49–0.82 and HR: 0.84, 95% CI: 0.72–0.98). Dabigatran was associated with a similar risk of stroke/SE compared to warfarin. Compared with warfarin, apixaban and dabigatran had a lower risk of MB (HR: 0.54, 95% CI: 0.49–0.61 and HR: 0.75, 95% CI: 0.63–0.91). Rivaroxaban was associated with a similar risk of MB compared to warfarin. In this high-risk population with obesity, NOACs had a varying risk of stroke/SE and MB vs. warfarin.

Cost of hospitalisation and length of stay due to hypoglycaemia in patients with diabetes mellitus: a cross-sectional study

Objective:

This study aims to estimate the length of stay and hospitalisation cost of hypoglycaemia, and to identify determinants of variation in the length of stay and hospitalisation cost among individual patients with type 1 or 2 diabetes mellitus.

Methods:

A cross-sectional study was conducted using inpatients records for patients with diabetes mellitus who had been hospitalised due to hypoglycaemic events in two private hospitals in Amman, Jordan between January 2009 and May 2017. All hospitalisation costs were inflated to the equivalent costs in 2017. Hospitalisation cost was estimated from the patient’s perspective in Jordanian dinars (JOD). Descriptive analyses and correlation between sociodemographic or clinical characteristics with the cost and length of stay were explored. Predictors of hypoglycaemic hospitalisation cost and length of stay were determined using logistic regression.

Results:

During the study period a total of 126 patients with diabetes mellitus were hospitalised due to an incident of hypoglycaemia. The mean patient age was 64.2 (SD=19.6) years; half were male. Patients admitted for hypoglycaemia stayed in hospital for a median duration of two days (IQR=2 days). The median cost of hospitalisation for hypoglycaemia was 163.2 JOD (USD 230.1) (IQR=216.3 JOD). We found that the Glasgow coma score was positively associated with length of stay (0.345, p=0.008), and older age was correlated with higher hospitalisation cost (0.207, p=0.02). Patients with a family history of diabetes had higher hospitalisation costs and longer duration of stay (0.306 and 0.275, p<0.05). In addition, being a male patient (0.394, p<0.05) and with an absence of smoking history was associated with longer duration of stay (0.456, p<0.01), but not with higher hospitalisation cost.

Conclusions:

Costs associated with the incidence of hypoglycaemic events are not low and constitute a large cost component of managing and treating diabetes mellitus. Male patients and patients having a family history of diabetes should receive extra care and education on the prevention of hypoglycaemic events, and a treatment de-intensification approach should be considered if necessary, so we can prevent its associated hospitalisation costs and length of stay.

Sobriety and Satiety: Is NAD+ the Answer?

Nicotinamide adenine dinucleotide (NAD+) is an essential pyridine nucleotide that has garnered considerable interest in the last century due to its critical role in cellular processes associated with energy production, cellular protection against stress and longevity. Research in NAD+ has been reinvigorated by recent findings that components of NAD+ metabolism and NAD-dependent enzymes can influence major signalling processes associated with the neurobiology of addiction. These studies implicate raising intracellular NAD+ levels as a potential target for managing and treating addictive behaviour and reducing cravings and withdrawal symptoms in patients with food addiction and/or substance abuse. Since clinical studies showing the use of NAD+ for the treatment of addiction are limited, this review provides literature evidence that NAD+ can influence the neurobiology of addiction and may have benefits as an anti-addiction intervention.

Sex Differences in the Association of Cumulative Body Mass Index from Early Adulthood to Middle Age and Left Atrial Remodeling Evaluated by Three-Dimensional Echocardiography: The Coronary Artery Risk Development in Young Adults Study

Background:

The relationship between long-term obesity and left atrial (LA) structure and function is not entirely understood. We examined the association of cumulative body mass index (cBMI) with LA remodeling using three-dimensional (3D) speckle-tracking echocardiography (STE).

Methods:

The Coronary Artery Risk Development in Young Adults (CARDIA) study is a community-based cohort of black and white, men and women, ages 18–30 years at baseline in 1985–86 from four U.S. centers. This study included 2,144 participants who had satisfactory image quality and body mass index measurements during the entire follow-up period. The 3D STE-derived LA parameters were maximum, minimum, and pretrial contraction volumes; total, passive, and active emptying fraction; maximum systolic longitudinal strain; and early and late diastolic longitudinal strain rates. Multivariable linear regression analyses stratified by sex assessed the relationship between cBMI and 3D STE-derived LA parameters, adjusting for demographics and traditional cardiovascular.

Results:

The mean age of the cohort was 55 ± 3.6 years; 54.8% were women, and 46.5% were black. There were statistically significant additive sex interactions for the association between cBMI and LA minimum contraction value, maximum systolic longitudinal strain, and early and late diastolic longitudinal strain rates. In the fully adjusted model, greater cBMI was associated with lower magnitude LA longitudinal deformation (maximum systolic longitudinal strain and early and late diastolic longitudinal strain rates) in men and with higher LA emptying fraction in women. In addition, greater cBMI was associated with higher LA phasic volumes indices in both men and women.

Conclusions:

This study showed that while greater cBMI from early adulthood throughout middle age was associated with higher LA volumes in both genders, differences were found for LA function, with lower longitudinal deformation in men and higher reservoir and active LA function in women. (J Am Soc Echocardiogr 2020;33:878–87.)

Association between insulin resistance and risk of atrial fibrillation in non-diabetics

AIMS

Previous studies from Western countries have been unable to demonstrate a relationship between insulin resistance and new-onset atrial fibrillation. We aimed to evaluate this relationship in the nondiabetic Asian population.

METHODS

Between 2001-2003, 8175 adults (mean age 51.5 years, 53% women) without both existing atrial fibrillation and diabetes and with insulin resistance measures at baseline were enrolled and were followed by biennial electrocardiograms thereafter until 2014. We constructed multivariable-adjusted Cox proportional hazard models for risk of incident atrial fibrillation.

RESULTS

Over a median follow-up of 12.3 years, 136 participants (1.89/1000 person-years) developed atrial fibrillation. Higher homeostasis model assessment of insulin resistance (HOMA-IR) was independently associated with newly developed atrial fibrillation (hazard ratio 1.61, 95% confidence interval 1.14-2.28). Atrial fibrillation development increased at the HOMA-IR levels approximately between 1-2.5, and then plateaued afterwards (p = 0.031).

CONCLUSION

There is a significant relationship between insulin resistance and atrial fibrillation development independent of other known risk factors, including obesity in a nondiabetic Asian population.

Obesity and atrial fibrillation: making inroads through fat

The global prevalence of obesity has reached epidemic proportions, paralleled by a rise in cases of atrial fibrillation (AF). Data from epidemiological cohorts support the role of obesity as an independent risk factor for AF. Increasing evidence indicates that obesity may contribute to the AF substrate through a number of pathways including by altering epicardial adipose tissue biology, inflammatory pathways, structural cardiac remodelling, and inducing atrial fibrosis. Due to changes in pharmacokinetics and pharmacodynamics, specific therapeutic considerations are required to guide management of patients with AF including anticoagulation and rhythm control. Also, weight loss in patients with AF has been associated with reduced progression from paroxysmal to persistent AF and indeed regression from persistent to proximal AF. However, the role of dietary intervention in AF control remains to be fully elucidated and hard prospective outcome data to support weight loss are required in AF to determine its role as part of a comprehensive risk factor management strategy for AF in obese patients.