The relative contribution of metabolic and structural abnormalities to diastolic dysfunction in obesity

Hyperpolarized 13C and 31P MRS detects differences in cardiac energetics, metabolism, and function in obesity, and responses following treatment

Obesity is associated with important changes in cardiac energetics and function, and an increased risk of adverse cardiovascular outcomes. Multi-nuclear MRS and MRI techniques have the potential to provide a comprehensive non-invasive assessment of cardiac metabolic perturbation in obesity. A rat model of obesity was created by high-fat diet feeding. This model was characterized using in vivo hyperpolarized [1-13C]pyruvate and [2-13C]pyruvate MRS, echocardiography and perfused heart 31P MRS. Two groups of obese rats were subsequently treated with either caloric restriction or the glucagon-like peptide-1 analogue/agonist liraglutide, prior to reassessment. The model recapitulated cardiovascular consequences of human obesity, including mild left ventricular hypertrophy, and diastolic, but not systolic, dysfunction. Hyperpolarized 13C and 31P MRS demonstrated that obesity was associated with reduced myocardial pyruvate dehydrogenase flux, altered cardiac tricarboxylic acid (TCA) cycle metabolism, and impaired myocardial energetic status (lower phosphocreatine to adenosine triphosphate ratio and impaired cardiac ΔG~ATP). Both caloric restriction and liraglutide treatment were associated with normalization of metabolic changes, alongside improvement in cardiac diastolic function. In this model of obesity, hyperpolarized 13C and 31P MRS demonstrated abnormalities in cardiac metabolism at multiple levels, including myocardial substrate selection, TCA cycle, and high-energy phosphorus metabolism. Metabolic changes were linked with impairment of diastolic function and were reversed in concert following either caloric restriction or liraglutide treatment. With hyperpolarized 13C and 31P techniques now available for human use, the findings support a role for multi-nuclear MRS in the development of new therapies for obesity.

Adiposity, fat-free mass and incident heart failure in 500 000 individuals

BACKGROUND AND AIMS

The independent role of body fat distribution and fat-free mass in heart failure (HF) risk is unclear. We investigated the role of different body composition compartments in risk of HF.

METHODS

Present analyses include 428 087 participants (mean age 55.9 years, 44% male) from the UK Biobank. Associations of long-term average levels of body composition measures with incident HF were determined using adjusted Cox proportional hazards regression models.

RESULTS

Over a median follow-up of 13.8 years, there were 10 455 first-ever incident HF events. Overall, HF risk was more strongly associated with central adiposity (waist circumference (WC) adjusted for body mass index (BMI); HR 1.38, 95% CI 1.32 to 1.45) than general adiposity (BMI adjusted for WC; HR 1.22, 95% CI 1.16 to 1.27). Although dual X-ray absorptiometry-derived body fat remained positively related to HF after adjustment for fat-free mass (HR 1.37, 95% CI 1.18 to 1.59), the association of fat-free mass with HF was substantially attenuated by fat mass (HR 1.12, 95% CI 1.01 to 1.26) while visceral fat (VAT) remained associated with HF independent of subcutaneous fat (HR 1.20, 95% CI 1.09 to 1.33). In analyses of HF subtypes, HF with preserved ejection fraction was independently associated with all fat measures (eg, VAT: HR 1.23, 95% CI 1.12 to 1.35; body fat: HR 1.36, 95% CI 1.17 to 1.57) while HF with reduced ejection fraction was not independently associated with fat measures (eg, VAT: HR 1.29, 95% CI 0.98 to 1.68; body fat: HR 1.29, 95% CI 0.80 to 2.07).

CONCLUSIONS

This large-scale study shows that excess adiposity and fat mass are associated with higher HF risk while the association of fat-free mass with HF could be explained largely by its correlation with fat mass. The study also describes the independent relevance of body fat distribution to HF subtypes, suggesting different mechanisms may be driving their aetiopathogenesis.

Circulating perturbation of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) is associated to cardiac remodeling and NLRP3 inflammasome in cardiovascular patients with insulin resistance risk

Lipidome perturbation occurring during meta-inflammation is associated to left ventricle (LV) remodeling though the activation of the NLRP3 inflammasome, a key regulator of chronic inflammation in obesity-related disorders. Little is known about phosphatidylcholine (PC) and phosphatidylethanolamine (PE) as DAMP-induced NLRP3 inflammasome. Our study is aimed to evaluate if a systemic reduction of PC/PE molar ratio can affect NLRP3 plasma levels in cardiovascular disease (CVD) patients with insulin resistance (IR) risk. Forty patients from IRCCS Policlinico San Donato were enrolled, and their blood samples were drawn before heart surgery. LV geometry measurements were evaluated by echocardiography and clinical data associated to IR risk were collected. PC and PE were quantified by ESI-MS/MS. Circulating NLRP3 was quantified by an ELISA assay. Our results have shown that CVD patients with IR risk presented systemic lipid impairment of PC and PE species and their ratio in plasma was inversely associated to NLRP3 levels. Interestingly, CVD patients with IR risk presented LV changes directly associated to increased levels of NLRP3 and a decrease in PC/PE ratio in plasma, highlighting the systemic effect of meta-inflammation in cardiac response. In summary, PC and PE can be considered bioactive mediators associated to both the NLRP3 and LV changes in CVD patients with IR risk.

From Beats to Metabolism: the Heart at the Core of Interorgan Metabolic Cross Talk

The heart, once considered a mere blood pump, is now recognized as a multifunctional metabolic and endocrine organ. Its function is tightly regulated by various metabolic processes, at the same time it serves as an endocrine organ, secreting bioactive molecules that impact systemic metabolism. In recent years, research has shed light on the intricate interplay between the heart and other metabolic organs, such as adipose tissue, liver, and skeletal muscle. The metabolic flexibility of the heart and its ability to switch between different energy substrates play a crucial role in maintaining cardiac function and overall metabolic homeostasis. Gaining a comprehensive understanding of how metabolic disorders disrupt cardiac metabolism is crucial, as it plays a pivotal role in the development and progression of cardiac diseases. The emerging understanding of the heart as a metabolic and endocrine organ highlights its essential contribution to whole body metabolic regulation and offers new insights into the pathogenesis of metabolic diseases, such as obesity, diabetes, and cardiovascular disorders. In this review, we provide an in-depth exploration of the heart's metabolic and endocrine functions, emphasizing its role in systemic metabolism and the interplay between the heart and other metabolic organs. Furthermore, emerging evidence suggests a correlation between heart disease and other conditions such as aging and cancer, indicating that the metabolic dysfunction observed in these conditions may share common underlying mechanisms. By unraveling the complex mechanisms underlying cardiac metabolism, we aim to contribute to the development of novel therapeutic strategies for metabolic diseases and improve overall cardiovascular health.

Myocardial steatosis across the spectrum of human health and disease

Preclinical data strongly suggest that myocardial steatosis leads to adverse cardiac remodelling and left ventricular dysfunction. Using 1 H cardiac magnetic resonance spectroscopy, similar observations have been made across the spectrum of health and disease. The purpose of this brief review is to summarize these recent observations. We provide a brief overview of the determinants of myocardial triglyceride accumulation, summarize the current evidence that myocardial steatosis contributes to cardiac dysfunction, and identify opportunities for further research.

Amyloid beta 42 alters cardiac metabolism and impairs cardiac function in male mice with obesity

There are epidemiological associations between obesity and type 2 diabetes, cardiovascular disease and Alzheimer's disease. The role of amyloid beta 42 (Aβ42) in these diverse chronic diseases is obscure. Here we show that adipose tissue releases Aβ42, which is increased from adipose tissue of male mice with obesity and is associated with higher plasma Aβ42. Increasing circulating Aβ42 levels in male mice without obesity has no effect on systemic glucose homeostasis but has obesity-like effects on the heart, including reduced cardiac glucose clearance and impaired cardiac function. The closely related Aβ40 isoform does not have these same effects on the heart. Administration of an Aβ-neutralising antibody prevents obesity-induced cardiac dysfunction and hypertrophy. Furthermore, Aβ-neutralising antibody administration in established obesity prevents further deterioration of cardiac function. Multi-contrast transcriptomic analyses reveal that Aβ42 impacts pathways of mitochondrial metabolism and exposure of cardiomyocytes to Aβ42 inhibits mitochondrial complex I. These data reveal a role for systemic Aβ42 in the development of cardiac disease in obesity and suggest that therapeutics designed for Alzheimer's disease could be effective in combating obesity-induced heart failure.

Obesity in Heart Failure with Reduced Ejection Fraction: Time to Address the Elephant in the Room

Obesity has been long recognized as a risk factor for the development of heart failure, but recent evidence suggests obesity is more typically associated with heart failure with preserved ejection fraction as opposed to heart failure with reduced ejection fraction (HFrEF). Nevertheless, numerous studies have found that obesity modulates the presentation and progression of HFrEF and may contribute to the development of HFrEF in some patients. Although obesity has definite negative effects in HFrEF patients, the effects of intentional weight loss in HFrEF patients with obesity have been poorly studied.

Current understanding of structural and molecular changes in diabetic cardiomyopathy

Diabetic Mellitus has been characterized as the most prevalent disease throughout the globe associated with the serious morbidity and mortality of vital organs. Cardiomyopathy is the major leading complication of diabetes and within this, myocardial dysfunction or failure is the leading cause of the emergency hospital admission. The review is aimed to comprehend the perspectives associated with diabetes-induced cardiovascular complications. The data was collected from several electronic databases such as Google Scholar, Science Direct, ACS publication, PubMed, Springer, etc. using the keywords such as diabetes and its associated complication, the prevalence of diabetes, the anatomical and physiological mechanism of diabetes-induced cardiomyopathy, the molecular mechanism of diabetes-induced cardiomyopathy, oxidative stress, and inflammatory stress, etc. The collected scientific data was screened by different experts based on the inclusion and exclusion criteria of the study. This review findings revealed that diabetes is associated with inefficient substrate utilization, inability to increase glucose metabolism and advanced glycation end products within the diabetic heart resulting in mitochondrial uncoupling, glucotoxicity, lipotoxicity, and initially subclinical cardiac dysfunction and finally in overt heart failure. Furthermore, several factors such as hypertension, overexpression of renin angiotensin system, hypertrophic obesity, etc. have been seen as majorly associated with cardiomyopathy. The molecular examination showed biochemical disability and generation of the varieties of free radicals and inflammatory cytokines and becomes are the substantial causes of cardiomyopathy. This review provides a better understanding of the involved pathophysiology and offers an open platform for discussing and targeting therapy in alleviating diabetes-induced early heart failure or cardiomyopathy.

Visceral adiposity index and the risk of heart failure, late-life cardiac structure, and function in ARIC study

BACKGROUND

It is well established that obesity is associated with the risk of heart failure (HF). However, the data about relationship between visceral fat and the risk of HF are limited.

AIMS

We aim to evaluate the association between visceral obesity assessed by visceral adiposity index (VAI) and incident HF and left ventricular (LV) structure and function in Atherosclerosis Risk in Communities (ARIC) study.

METHODS

We included 12 161 participants (aged 54.1 ± 5.8 years) free of history of HF and coronary heart disease at baseline (1987-89) in ARIC study. We used multivariable Cox hazard regression models to assess the association between the VAI and incident HF. We further explored the effects of the VAI on LV geometry and function among 4817 participants with echocardiographic data using multivariable linear regression analysis and multinomial logistic regression.

RESULTS

During a median follow-up of 22.5 years, a total of 1904 (15.7%) participants developed HF. After adjustment for traditional HF risk factors, 1 unit increase in the baseline VAI was associated with an 8% higher risk of incident HF [hazard ratio (HR): 1.08, 95% confidence interval (CI): 1.06-1.11]. Results were similar when participants were categorized by VAI tertiles. Compared with participants in the lowest tertile of VAI, those in the second tertile and third tertile had a greater risk of incident HF [HR (95% CI): 1.19 (1.05-1.34) and 1.42 (1.26-1.61), respectively]. For the analyses of the HF subtypes, the higher VAI was only associated with the risk of HF with preserved ejection fraction, not with HF with reduced ejection fraction. In addition, the greater VAI was associated with worse LV diastolic function and abnormal LV geometry including concentric remodelling, concentric hypertrophy, and eccentric hypertrophy.

CONCLUSION

This study shows that higher VAI was independently associated with the increased risk of incident HF and abnormal LV geometry and LV diastolic dysfunction.

Whole-Body Magnetic Resonance Imaging Assessment of the Contributions of Adipose and Nonadipose Tissues to Cardiovascular Remodeling in Adolescents

Background Greater body mass index is associated with cardiovascular remodeling in adolescents. However, body mass index cannot differentiate between adipose and nonadipose tissues. We examined how visceral and subcutaneous adipose tissue are linked with markers of early cardiovascular remodeling, independently from nonadipose tissue. Methods and Results Whole-body magnetic resonance imaging was done in 82 adolescents (39 overweight/obese; 36 female; median age, 16.3 [interquartile range, 14.4-18.1] years) to measure body composition and cardiovascular remodeling markers. Left ventricular diastolic function was assessed by echocardiography. Waist, waist:height ratio, and body mass index z scores were calculated. Residualized nonadipose tissue, subcutaneous adipose tissue, and visceral adipose tissue variables, uncorrelated with each other, were constructed using partial regression modeling to allow comparison of their individual contributions in a 3-compartment body composition model. Cardiovascular variables mostly related to nonadipose rather than adipose tissue. Nonadipose tissue was correlated positively with left ventricular mass (r=0.81), end-diastolic volume (r=0.70), stroke volume (r=0.64), left ventricular mass:end-diastolic volume (r=0.37), and systolic blood pressure (r=0.35), and negatively with heart rate (r=-0.33) (all P<0.01). Subcutaneous adipose tissue was associated with worse left ventricular diastolic function (r=-0.42 to -0.48, P=0.0007-0.02) and higher heart rates (r=0.34, P=0.007) but linked with better systemic vascular resistance (r=-0.35, P=0.006). There were no significant relationships with visceral adipose tissue and no associations of any compartment with pulse wave velocity. Conclusions Simple anthropometry does not reflect independent effects of nonadipose tissue and subcutaneous adipose tissue on the adolescent cardiovascular system. This could result in normal cardiovascular adaptations to growth being misinterpreted as pathological sequelae of excess adiposity in studies reliant on such measures.

Body Composition and Risk of Incident Heart Failure in 1 Million Adults: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies

Background The aim of this systematic review was to quantify the associations between body composition measures and risk of incident heart failure (HF) and its subtypes in the general population. Methods and Results We searched Medline, Embase, and Global Health databases from each database inception to January 19, 2023 for prospective studies reporting on body composition and HF risk. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The Newcastle-Ottawa scale was used to assess the risk of bias of included studies. Fixed-effects models were used for meta-analysis. Thirty-five studies were included (ntotal=1 137 044; ncases=34 422). Summary relative risk (RR) per 5-kg/m2 higher body mass index was 1.42 (95% CI, 1.40-1.42; 𝜁2=0.02, I2=94.4%), 1.28 (95% CI, 1.26-1.31; 𝜁2=0.01, I2=75.8%) per 10-cm higher waist circumference, and 1.33 (95% CI, 1.28-1.37; 𝜁2=0.04, I2=94.9%) per 0.1-unit higher waist-hip ratio. Pooled estimates of the few studies that reported on regional fat suggested significant positive association between HF risk and both visceral fat (RR, 1.08 [95% CI, 1.04-1.12]) and pericardial fat (RR, 1.08 [95% CI, 1.06-1.10]). Among HF subtypes, associations were stronger for HF with preserved ejection fraction than HF with reduced ejection fraction. No study reported on lean mass. Conclusions Pooled data suggested strong associations between adiposity and HF. The association with adiposity is stronger for HF with preserved ejection fraction than HF with reduced ejection fraction, indicating that different mechanisms may be at play in etiopathogenesis of HF subtypes. Future studies are needed to investigate role of regional fat mass and lean mass in HF risk. Registration Information REGISTRATION: URL: www.crd.york.ac.uk/prospero/. Unique identifier: CRD42020224584.

Is increased myocardial triglyceride content associated with early changes in left ventricular function? A 1H-MRS and MRI strain study

Background

Type 2 diabetes (T2D) and obesity induce left ventricular (LV) dysfunction. The underlying pathophysiological mechanisms remain unclear, but myocardial triglyceride content (MTGC) could be involved.

Objectives

This study aimed to determine which clinical and biological factors are associated with increased MTGC and to establish whether MTGC is associated with early changes in LV function.

Methods

A retrospective study was conducted using five previous prospective cohorts, leading to 338 subjects studied, including 208 well-phenotyped healthy volunteers and 130 subjects living with T2D and/or obesity. All the subjects underwent proton magnetic resonance spectroscopy and feature tracking cardiac magnetic resonance imaging to measure myocardial strain.

Results

MTGC content increased with age, body mass index (BMI), waist circumference, T2D, obesity, hypertension, and dyslipidemia, but the only independent correlate found in multivariate analysis was BMI (p=0.01; R²=0.20). MTGC was correlated to LV diastolic dysfunction, notably with the global peak early diastolic circumferential strain rate (r=-0.17, p=0.003), the global peak late diastolic circumferential strain rate (r=0.40, p<0.0001) and global peak late diastolic longitudinal strain rate (r=0.24, p<0.0001). MTGC was also correlated to systolic dysfunction via end-systolic volume index (r=-0.34, p<0.0001) and stroke volume index (r=-0.31, p<0.0001), but not with longitudinal strain (r=0.009, p=0.88). Interestingly, the associations between MTGC and strain measures did not persist in multivariate analysis. Furthermore, MTGC was independently associated with LV end-systolic volume index (p=0.01, R²=0.29), LV end-diastolic volume index (p=0.04, R²=0.46), and LV mass (p=0.002, R²=0.58).

Conclusions

Predicting MTGC remains a challenge in routine clinical practice, as only BMI independently correlates with increased MTGC. MTGC may play a role in LV dysfunction but does not appear to be involved in the development of subclinical strain abnormalities.

The role of obesity-related cardiovascular remodelling in mediating incident cardiovascular outcomes: a population-based observational study

AIMS

We examined associations of obesity with incident cardiovascular outcomes and cardiovascular magnetic resonance (CMR) phenotypes, integrating information from body mass index (BMI) and waist-to-hip ratio (WHR). Then, we used multiple mediation to define the role of obesity-related cardiac remodelling in driving obesity-outcome associations, independent of cardiometabolic diseases.

METHODS AND RESULTS

In 491 606 UK Biobank participants, using Cox proportional hazard models, greater obesity (higher WHR, higher BMI) was linked to significantly greater risk of incident ischaemic heart disease, atrial fibrillation (AF), heart failure (HF), all-cause mortality, and cardiovascular disease (CVD) mortality. In combined stratification by BMI and WHR thresholds, elevated WHR was associated with greater risk of adverse outcomes at any BMI level. Individuals with overweight BMI but normal WHR had weaker disease associations. In the subset of participants with CMR (n = 31 107), using linear regression, greater obesity was associated with higher left ventricular (LV) mass, greater LV concentricity, poorer LV systolic function, lower myocardial native T1, larger left atrial (LA) volumes, poorer LA function, and lower aortic distensibility. Of note, higher BMI was linked to higher, whilst greater WHR was linked to lower LV end-diastolic volume (LVEDV). In Cox models, greater LVEDV and LV mass (LVM) were linked to increased risk of CVD, most importantly HF and an increased LA maximal volume was the key predictive measure of new-onset AF. In multiple mediation analyses, hypertension and adverse LV remodelling (higher LVM, greater concentricity) were major independent mediators of the obesity-outcome associations. Atrial remodelling and native T1 were additional mediators in the associations of obesity with AF and HF, respectively.

CONCLUSIONS

We demonstrate associations of obesity with adverse cardiovascular phenotypes and their significant independent role in mediating obesity-outcome relationships. In addition, our findings support the integrated use of BMI and WHR to evaluate obesity-related cardiovascular risk.

Health Complications of Obesity: 224 Obesity-Associated Comorbidities from a Mechanistic Perspective

Obesity is associated with a wide range of comorbidities that transverse multiple specialties in clinical medicine. The development of these comorbidities is driven by various mechanistic changes including chronic inflammation and oxidative stress, increased growth-promoting adipokines, insulin resistance, endothelial dysfunction, direct loading and infiltrative effect of adiposity, heightened activities of the renin-angiotensin-aldosterone system and sympathetic nervous system, impaired immunity, altered sex hormones, altered brain structure, elevated cortisol levels, and increased uric acid production, among others. Some of the comorbidities might develop secondary to one or more other comorbidities. Considering the obesity-associated comorbidities in the context of the mechanistic changes is helpful in understanding these conditions and in guiding treatment and future research.

Functional and Metabolic Imaging in Heart Failure with Preserved Ejection Fraction: Promises, Challenges, and Clinical Utility

Heart failure with preserved ejection fraction (HFpEF) is recognised as an increasingly prevalent, morbid and burdensome condition with a poor outlook. Recent advances in both the understanding of HFpEF and the technological ability to image cardiac function and metabolism in humans have simultaneously shone a light on the molecular basis of this complex condition of diastolic dysfunction, and the inflammatory and metabolic changes that are associated with it, typically in the context of a complex patient. This review both makes the case for an integrated assessment of the condition, and highlights that metabolic alteration may be a measurable outcome for novel targeted forms of medical therapy. It furthermore highlights how recent technological advancements and advanced medical imaging techniques have enabled the characterisation of the metabolism and function of HFpEF within patients, at rest and during exercise.

Prevalence of cardiovascular manifestations in patients with hypermobile Ehlers-Danlos syndrome at the University of Miami

Cardiovascular system involvements have been frequently reported in hypermobile Ehlers-Danlos Syndrome (hEDS). Mitral valve prolapse (MVP) and aortic root dilatation are included in the 2017 international classification criteria for hEDS. Different studies have found conflicting results regarding the significance of cardiac involvement in hEDS patients. We conducted a retrospective review of cardiac involvement in patients diagnosed with hEDS based on the 2017 International diagnostic criteria to provide further evidence toward more defined and reliable diagnostic criteria and recommended cardiac surveillance. A total of 75 hEDS patients with at least one diagnostic cardiac evaluation were included in the study. The most common reported cardiovascular complaints were lightheadedness (80.6%), followed by palpitations (77.6%), fainting (44.8%), and chest pain (32.8%). Of the 62 echocardiogram reports, 57 (91.9%) showed trace/trivial to mild valvular insufficiency, and 13 (21%) had additional abnormalities such as grade I diastolic dysfunction, mild aortic sclerosis, and trivial or small pericardial effusion. Of the 60 electrocardiograms (ECG) reports, 39 (65%) were normal, and 21 (35%) reported minor abnormalities or normal variants. Even though many hEDS patients in our cohort experienced cardiac symptoms, the presence of a significant cardiac abnormality was very low.

Molecular mechanisms underlying the beneficial effects of exercise and dietary interventions in the prevention of cardiometabolic diseases

Cardiometabolic diseases still represent a major cause of mortality worldwide. In addition to pharmacological approaches, lifestyle interventions can also be adopted for the prevention of these morbid conditions. Lifestyle changes include exercise and dietary restriction protocols, such as calorie restriction and intermittent fasting, which were shown to delay cardiovascular ageing and elicit health-promoting effects in preclinical models of cardiometabolic diseases. Beneficial effects are mediated by the restoration of multiple molecular mechanisms in heart and vessels that are compromised by metabolic stress. Exercise and dietary restriction rescue mitochondrial dysfunction, oxidative stress and inflammation. They also improve autophagy. The result of these effects is a marked improvement of vascular and heart function. In this review, we provide a comprehensive overview of the molecular mechanisms involved in the beneficial effects of exercise and dietary restriction in models of diabetes and obesity. We also discuss clinical studies and gap in animal-to-human translation.

The Impact of Metabolic Syndrome and Obesity on the Evolution of Diastolic Dysfunction in Apparently Healthy Patients Suffering from Post-COVID-19 Syndrome

(1) Background: Coronavirus disease 2019 (COVID-19) has a worse prognosis in individuals with obesity and metabolic syndrome (MS), who often develop cardiovascular complications that last throughout recovery. (2) Methods: This study aimed to analyze the evolution of diastolic dysfunction (DD), assessed by transthoracic echocardiography (TTE), in 203 individuals with and without obesity and/or MS diagnosed with post-COVID-19 syndrome. (3) Results: DD was frequently diagnosed in patients with MS and obesity, but also in those without obesity (62.71% and 56.6%, respectively), in comparison to 21.97% of subjects without MS (p ˂ 0.001). Almost half of the patients with obesity and MS had more severe DD (types 2 and 3). As for evolution, the prevalence and severity of DD, particularly types 1 and 2, decreased gradually, in parallel with the improvement of symptoms, progress being more evident in subjects without MS. DD of type 3 did not show a significant reduction (p = 0.47), suggesting irreversible myocardial damages. Multivariate regression analysis indicated that the number of MS factors, the severity of initial pulmonary injury, and protein C levels could explain DD evolution. (4) Conclusions: DD was commonly diagnosed in individuals with post-COVID-19 syndrome, particularly in those with MS and obesity. After 6 months, DD evolution, excepting that of type 3, showed a significant improvement, mostly in patients without MS.

Association between metabolic syndrome and left ventricular geometric change including diastolic dysfunction

BACKGROUND

We investigated the association between individual components of metabolic syndrome (MetS) and left ventricular (LV) geometric changes, including diastolic dysfunction, in a large cohort of healthy individuals.

METHODS

Overall, 148 461 adults who underwent echocardiography during a health-screening program were enrolled. Geographic characteristics on echocardiography and several markers of LV relaxation function were identified according to individual MetS components. Univariate linear regression analysis and a multivariate regression model adjusted for factors known to influence LV relaxation function were conducted.

RESULTS

The prevalence of LV diastolic dysfunction (LVDD) was higher in the MetS group than in the non-MetS group (0.56% vs. 0.27%, p < .001). In univariate and multivariate analyses, E/A ratio, e' velocity, and left atrial volume index were significantly associated with each component of MetS and covariates (all p ≤ .001). In the age- and sex-adjusted model, MetS was significantly associated with LVDD (odds ratio [95% confidence interval], 1.350 [1.103, 1.652]). However, subjects with more MetS components did not have a significantly higher risk of LVDD. As the analysis was stratified by sex, the multivariate regression model showed that MetS was significantly associated with LVDD only in men (1.3 [1.00, 1.68]) with higher risk in more MetS component (p for trend < .001). In particular, triglyceride (TG) and waist circumference (WC) among MetS components were significantly associated with LVDD in men.

CONCLUSIONS

MetS was associated with the risk of LVDD, especially in men, with a dose-dependent association between an increasing number of components of MetS and LVDD. TG and WC were independent risk factors for LVDD in men.

P2X7 Receptor and Heart Function in a Mouse Model of Systemic Inflammation Due to High Fat Diet

Purpose

Low-grade inflammation contributes to heart failure in obesity or type 2 diabetes mellitus. The P2X7 receptor (P2X7R) is a key regulator of several pro-inflammatory responses in multiple tissues and organs; however, its involvement in the onset of heart dysfunction remains unclear. The study evaluated the role of P2X7R as a cardiac function regulator in C57BL/6J wild-type (WT) and P2X7R knockout (KO) mice by inducing systemic inflammation with high fat diet (HFD).

Methods

Specific parameters of systolic and diastolic function and heart morphology were measured in vivo before animal sacrifice by high-frequency ultrasonographic analysis. Gene and protein expression of cardiac biomarkers associated with inflammatory-oxidative pathways were evaluated by real-time PCR and Western Blotting.

Results

P2X7R-mediated up-regulation of the NLRP3-caspase-1 complex, increased expression of key oxidative stress (NOS-2, TNFα), and chemotactic (MCP-1) mediators were revealed in WT-HFD animals. In KO-HFD mice, such inflammatory-oxidative pathway was silent. Nevertheless, HFD induced in vivo a clear alteration of diastolic pattern (E/A: p < 0.03 vs WT-HFD) and a cardiac morphologic remodelling (left ventricular mass: p < 0.05 vs WT-HFD) only in P2X7R KO animals. Surprisingly, the transcriptional and protein expression of IL-1β and IL-6, usually regulated through P2X7R activation, were significantly higher in KO-HFD than in WT-HFD mice (both p < 0.05). Furthermore, an up-regulation of miR-214 and a down-regulation of miR-126 in heart of HFD-KO mice were observed, suggesting a link between such epigenetic dysregulation and cytokine overexpression as a potential pathophysiologic mechanism concurring to the progressive cardiac dysfunction.

Conclusion

These findings seem to suggest a cardioprotective role of P2X7R toward this tissue-specific inflammatory damage, likely through tissue homeostasis and organ functionality preservation.

Impact Of Obesity On Cardiac Structural And Functional Changes

The urgency of obesity issue is undeniable. Obesity is now considered the most important risk factor of cardiovascular diseases. Numerous studies have demonstrated the negative effect of excessive adipose tissue on structural and functional changes in the heart that lead to development of left ventricular hypertrophy, arrhythmias and conduction abnormalities, as well as progression of diastolic and systolic heart failure. High prevalence of obesity – so high that it can be called a pandemic – greatly contributes to the increased incidence of cardiovascular diseases. Studying the problem of obesity is a priority area of focus for modern medicine. This article describes hormonal, metabolic and hemodynamic features of obesity impact on cardiovascular system and describes pathogenetic mechanisms of cardiovascular pathology development.

Diabetes Mellitus and Heart Failure With Preserved Ejection Fraction: Role of Obesity

Heart failure with preserved ejection fraction is a growing epidemic and accounts for half of all patients with heart failure. Increasing prevalence, morbidity, and clinical inertia have spurred a rethinking of the pathophysiology of heart failure with preserved ejection fraction. Unlike heart failure with reduced ejection fraction, heart failure with preserved ejection fraction has distinct clinical phenotypes. The obese-diabetic phenotype is the most often encountered phenotype in clinical practice and shares the greatest burden of morbidity and mortality. Left ventricular remodeling plays a major role in its pathophysiology. Understanding the interplay of obesity, diabetes mellitus, and inflammation in the pathophysiology of left ventricular remodeling may help in the discovery of new therapeutic targets to improve clinical outcomes in heart failure with preserved ejection fraction. Anti-diabetic agents like glucagon-like-peptide 1 analogs and sodium-glucose co-transporter 2 are promising therapeutic modalities for the obese-diabetic phenotype of heart failure with preserved ejection fraction and aggressive weight loss via lifestyle or bariatric surgery is still key to reverse adverse left ventricular remodeling. This review focuses on the obese-diabetic phenotype of heart failure with preserved ejection fraction highlighting the interaction between obesity, diabetes, and coronary microvascular dysfunction in the development and progression of left ventricular remodeling. Recent therapeutic advances are reviewed.

Crossroads between Estrogen Loss, Obesity, and Heart Failure with Preserved Ejection Fraction

The prevalence of obesity and heart failure with preserved ejection fraction (HFpEF) increases significantly in postmenopausal women. Although obesity is a risk factor for left ventricular diastolic dysfunction (LVDD), the mechanisms that link the cessation of ovarian hormone production, and particularly estrogens, to the development of obesity, LVDD, and HFpEF in aging females are unclear. Clinical, and epidemiologic studies show that postmenopausal women with abdominal obesity (defined by waist circumference) are at greater risk for developing HFpEF than men or women without abdominal obesity. The study presents a review of clinical data that support a mechanistic link between estrogen loss plus obesity and left ventricular remodeling with LVDD. It also seeks to discuss potential cell and molecular mechanisms for estrogen-mediated protection against adverse adipocyte cell types, tissue depots, function, and metabolism that may contribute to LVDD and HFpEF.

Energetic Basis for Exercise-Induced Pulmonary Congestion in Heart Failure With Preserved Ejection Fraction

BACKGROUND

Transient pulmonary congestion during exercise is emerging as an important determinant of reduced exercise capacity in heart failure with preserved ejection fraction (HFpEF). We sought to determine whether an abnormal cardiac energetic state underpins this process.

METHODS

We recruited patients across the spectrum of diastolic dysfunction and HFpEF (controls, n=11; type 2 diabetes, n=9; HFpEF, n=14; and severe diastolic dysfunction attributable to cardiac amyloidosis, n=9). Cardiac energetics were measured using phosphorus spectroscopy to define the myocardial phosphocreatine to ATP ratio. Cardiac function was assessed by cardiovascular magnetic resonance cine imaging and echocardiography and lung water using magnetic resonance proton density mapping. Studies were performed at rest and during submaximal exercise using a magnetic resonance imaging ergometer.

RESULTS

Paralleling the stepwise decline in diastolic function across the groups (E/e' ratio; P<0.001) was an increase in NT-proBNP (N-terminal pro-brain natriuretic peptide; P<0.001) and a reduction in phosphocreatine/ATP ratio (control, 2.15 [2.09, 2.29]; type 2 diabetes, 1.71 [1.61, 1.91]; HFpEF, 1.66 [1.44, 1.89]; cardiac amyloidosis, 1.30 [1.16, 1.53]; P<0.001). During 20-W exercise, lower left ventricular diastolic filling rates (r=0.58; P<0.001), lower left ventricular diastolic reserve (r=0.55; P<0.001), left atrial dilatation (r=-0.52; P<0.001), lower right ventricular contractile reserve (right ventricular ejection fraction change, r=0.57; P<0.001), and right atrial dilation (r=-0.71; P<0.001) were all linked to lower phosphocreatine/ATP ratio. Along with these changes, pulmonary proton density mapping revealed transient pulmonary congestion in patients with HFpEF (+4.4% [0.5, 6.4]; P=0.002) and cardiac amyloidosis (+6.4% [3.3, 10.0]; P=0.004), which was not seen in healthy controls (-0.1% [-1.9, 2.1]; P=0.89) or type 2 diabetes without HFpEF (+0.8% [-1.7, 1.9]; P=0.82). The development of exercise-induced pulmonary congestion was associated with lower phosphocreatine/ATP ratio (r=-0.43; P=0.004).

CONCLUSIONS

A gradient of myocardial energetic deficit exists across the spectrum of HFpEF. Even at low workload, this energetic deficit is related to markedly abnormal exercise responses in all 4 cardiac chambers, which is associated with detectable pulmonary congestion. The findings support an energetic basis for transient pulmonary congestion in HFpEF.

The effect of overweight/obesity on diastolic function in children and adolescents: A meta-analysis

Left ventricular diastolic function (LVDF) is an important marker of early cardiovascular remodelling, which has not been well summarized in young people with overweight/obesity. Weighted, random-effects regression was used to determine the strength of associations of both body mass index (BMI) and homeostatic model assessment of insulin resistance (HOMA-IR) with LVDF measures, adjusting for age and sex. Six databases were searched after PROSPERO registration (CRD42020177470) from inception to July 2020 for studies that compared LVDF between overweight/obesity and control groups aged ≤24 years, yielding 70 studies (9983 individuals). Quality and risk of bias were assessed using NHLBI tools, with scores of good, fair, and poor for 6, 48, and 16 studies, respectively. Increased BMI was associated with worse LVDF in all measures except early mitral inflow deceleration time, with septal early diastolic tissue peak velocity to late diastolic tissue peak velocity ratio having the strongest association (n = 13 studies, 1824 individuals; r = -0.69; P < 0.001). Elevated HOMA-IR was also associated with worse LVDF. Although we could not determine the causality of reduced LVDF in young people, our findings should aid the development of paediatric guidelines for the assessment of LVDF and support further work to address the longitudinal consequences of childhood obesity and IR on LVDF.

Obesity modifies the energetic phenotype of dilated cardiomyopathy

AIMS

We sought to determine if myocardial energetics could distinguish obesity cardiomyopathy as a distinct entity from dilated cardiomyopathy.

METHODS AND RESULTS

Sixteen normal weight participants with dilated cardiomyopathy (DCMNW), and 27 with DCM and obesity (DCMOB), were compared to 26 normal weight controls (CTLNW). All underwent cardiac magnetic resonance imaging and 31P spectroscopy to assess function and energetics. Nineteen DCMOB underwent repeat assessment after a dietary weight loss intervention. Adenosine triphosphate (ATP) delivery through creatine kinase (CK flux) was 55% lower in DCMNW than in CTLNW (P = 0.004), correlating with left ventricular ejection fraction (LVEF, r = 0.4, P = 0.015). In contrast, despite similar LVEF (DCMOB 41 ± 7%, DCMNW 38 ± 6%, P = 0.14), CK flux was two-fold higher in DCMOB (P < 0.001), due to higher rate through CK [median kf 0.21 (0.14) vs. 0.11 (0.12) s-1, P = 0.002]. During increased workload, the CTLNW heart increased CK flux by 97% (P < 0.001). In contrast, CK flux was unchanged in DCMNW and fell in DCMOB (by >50%, P < 0.001). Intentional weight loss was associated with positive left ventricular remodelling, with reduced left ventricular end-diastolic volume (by 8%, P < 0.001) and a change in LVEF (40 ± 9% vs. 45 ± 10%, P = 0.002). This occurred alongside a fall in ATP delivery rate with weight loss (by 7%, P = 0.049).

CONCLUSIONS

In normal weight, DCM is associated with reduced resting ATP delivery. In obese DCM, ATP demand through CK is greater, suggesting reduced efficiency of energy utilization. Dietary weight loss is associated with significant improvement in myocardial contractility, and a fall in ATP delivery, suggesting improved metabolic efficiency. This highlights distinct energetic pathways in obesity cardiomyopathy, which are both different from dilated cardiomyopathy, and may be reversible with weight loss.

Bariatric surgery decreases the number of future hospital admissions for diastolic heart failure in subjects with severe obesity: a retrospective analysis of the US National Inpatient Sample database

BACKGROUND

Considerable evidence documents the effectiveness and efficacy of bariatric surgery (BaS) in reducing the prevalence and severity of obesity-related co-morbidities. Diastolic heart failure (DHF) is a condition with considerable morbidity and mortality, yet recalcitrant to medical therapy.

OBJECTIVE

Our objectives were to assess whether BaS is associated with a decrease in hospital admissions for DHF and determine its impact upon DHF hospital admissions among patients with hypertension (HTN) and coronary artery disease (CAD).

SETTING

Academic institution.

METHODS

Data on 296 041 BaS cases and 2 004 804 controls with severe obesity were extracted from the US National Inpatient Sample database for the years 2010 to 2015 and compared. Univariate and multivariable analysis were performed to assess the impact of pre-2010 BaS on the rate of hospital admissions for DHF, adjusting for demographics, co-morbidities, and other risk factors associated with cardiovascular disease (CVD).

RESULTS

Relative to controls, all baseline CVD risk factors were less common among BaS cases. Nonetheless, even after adjusting for all CVD risk factors, controls exhibited marked increases in the odds of DHF overall (odds ratio = 2.80; 95% confidence interval = 2.52-3.10). Controls with HTN and CAD demonstrated an almost 3-fold increase in odds of DHF admissions. Similarly, controls with no HTN demonstrated a 5-fold increase in odds of admissions for DHF when compared to the surgical group.

CONCLUSIONS

In this retrospective, case control study of a large, representative national sample of patients with severely obesity, BaS was found to be associated with significantly reduced hospitalizations for DHF when adjusted for baseline CVD risk factors. It also reduced DHF incidence in high-risk patients with HTN and CAD.

Obesity cardiomyopathy: evidence, mechanisms, and therapeutic implications

The prevalence of heart failure is on the rise and imposes a major health threat, in part, due to the rapidly increased prevalence of overweight and obesity. To this point, epidemiological, clinical, and experimental evidence supports the existence of a unique disease entity termed “obesity cardiomyopathy,” which develops independent of hypertension, coronary heart disease, and other heart diseases. Our contemporary review evaluates the evidence for this pathological condition, examines putative responsible mechanisms, and discusses therapeutic options for this disorder. Clinical findings have consolidated the presence of left ventricular dysfunction in obesity. Experimental investigations have uncovered pathophysiological changes in myocardial structure and function in genetically predisposed and diet-induced obesity. Indeed, contemporary evidence consolidates a wide array of cellular and molecular mechanisms underlying the etiology of obesity cardiomyopathy including adipose tissue dysfunction, systemic inflammation, metabolic disturbances (insulin resistance, abnormal glucose transport, spillover of free fatty acids, lipotoxicity, and amino acid derangement), altered intracellular especially mitochondrial Ca²⁺ homeostasis, oxidative stress, autophagy/mitophagy defect, myocardial fibrosis, dampened coronary flow reserve, coronary microvascular disease (microangiopathy), and endothelial impairment. Given the important role of obesity in the increased risk of heart failure, especially that with preserved systolic function and the recent rises in COVID-19-associated cardiovascular mortality, this review should provide compelling evidence for the presence of obesity cardiomyopathy, independent of various comorbid conditions, underlying mechanisms, and offer new insights into potential therapeutic approaches (pharmacological and lifestyle modification) for the clinical management of obesity cardiomyopathy.

NLRP3 inflammasome deficiency attenuates metabolic disturbances involving alterations in the gut microbial profile in mice exposed to high fat diet

Obesity-related diseases (e.g. type 2 diabetes mellitus and cardiovascular disorders) represent an increasing health problem worldwide. NLRP3 inflammasome activation may underlie obesity-induced inflammation and insulin resistance, and NLRP3 deficient mice exposed to high fat diet (HFD) appear to be protected from left ventricle (LV) concentric remodeling. Herein, we investigated if these beneficial effects were associated with alterations in plasma metabolites, using metabolomic and lipidomic analysis, and gut microbiota composition, using 16S rRNA sequencing of cecum content, comparing NLRP3 deficient and wild type (WT) mice on HFD and control diet. Obese NLRP3 deficient mice had lower systemic ceramide levels, potentially resulting attenuating inflammation, altered hepatic expression of fatty acids (FA) with lower mono-saturated FA and higher polyunsaturated FA levels, potentially counteracting development of liver steatosis, downregulated myocardial energy metabolism as assessed by proteomic analyses of LV heart tissue, and different levels of bile acids as compared with WT mice. These changes were accompanied by an altered composition of gut microbiota associated with decreased systemic levels of tri-methylamine-N-oxide and lipopolysaccharide, potentially inducing attenuating systemic inflammation and beneficial effects on lipid metabolism. Our findings support a role of NLRP3 inflammasome in the interface between metabolic and inflammatory stress, involving an altered gut microbiota composition.

The role of insulin resistance in the relation of visceral, abdominal subcutaneous and total body fat to cardiovascular function

BACKGROUND AND AIMS

The separate cardiovascular effects of type 2 diabetes and adiposity remain to be examined. This study aimed to investigate the role of insulin resistance in the relations of visceral (VAT), abdominal subcutaneous (aSAT) adipose tissue and total body fat (TBF) to cardiovascular remodeling.

METHODS AND RESULTS

In this cross-sectional analysis of the population-based Netherlands Epidemiology of Obesity study, 914 middle-aged individuals (46% men) were included. Participants underwent magnetic resonance imaging. Standardized linear regression coefficients (95%CI) were calculated, adjusted for potential confounding factors. All fat depots and insulin resistance (HOMA-IR), separate from VAT and TBF, were associated with lower mitral early and late peak filling rate ratios (E/A): -0.04 (-0.09;0.01) per SD (54 cm²) VAT; -0.05 (-0.10;0.00) per SD (94 cm²) aSAT; -0.09 (-0.16;-0.02) per SD (8%) TBF; -0.11 (-0.17;-0.05) per 10-fold increase in HOMA-IR, whereas VAT and TBF were differently associated with left ventricular (LV) end-diastolic volume: -8.9 (-11.7;-6.1) mL per SD VAT; +5.4 (1.1;9.7) mL per SD TBF. After adding HOMA-IR to the model to evaluate the mediating role of insulin resistance, change in E/A was -0.02 (-0.07;0.04) per SD VAT; -0.03 (-0.08;0.02) per SD aSAT; -0.06 (-0.13;0.01) per SD TBF, and change in LV end-diastolic volume was -7.0 (-9.7;-4.3) mL per SD VAT. In women, adiposity but not HOMA-IR was related to higher aortic arch pulse wave velocity.

CONCLUSION

Insulin resistance was associated with reduced diastolic function, separately from VAT and TBF, and partly mediated the associations between adiposity depots and lower diastolic function.

Left Ventricular Diastolic and Systolic Functions in Patients with Hypothyroidism

Background and objectives: Long standing hypothyroidism may impair myocardial relaxation, but its effect on systolic myocardial function is still controversial. The aim of this study was to investigate left ventricular (LV) systolic and diastolic function in patients with hypothyroidism. Materials and Methods: This study included 81 (age 42 ± 13 years, 92% female) patients with hypothyroidism, and 22 age and gender matched controls. All subjects underwent a detailed clinical examination followed by a complete biochemical blood analysis including thyroid function assessment and anthropometric parameters measurements. LV function was assessed by 2-dimensional, M-mode and Tissue-Doppler Doppler echocardiographic examination performed in the same day. Results: Patients had lower waist/hip ratio (p< 0.001), higher urea level (p = 0.002), and lower white blood cells (p = 0.011), compared with controls. All other clinical, biochemical, and anthropometric data did not differ between the two groups. Patients had impaired LV diastolic function (lower E wave [p< 0.001], higher A wave [p = 0.028], lower E/A ratio [p< 0.001], longer E wave deceleration time [p = 0.01], and higher E/e' ratio [p< 0.001]), compared with controls. Although LV global systolic function did not differ between groups, LV longitudinal systolic function was compromised in patients (lateral mitral annular plane systolic excursion-MAPSE [p = 0.005], as were lateral and septal s' [p< 0.001 for both]). Conclusions: In patients with hypothyroidism, in addition to compromised LV diastolic function, LV longitudinal systolic function is also impaired compared to healthy subjects of the same age and gender. These findings suggest significant subendocardial function impairment, reflecting potentially micro-circulation disease that requires optimum management.

Quantifying the effect of dobutamine stress on myocardial Pi and pH in healthy volunteers: A 31 P MRS study at 7T

Purpose

Phosphorus spectroscopy (³¹P‐MRS) is a proven method to probe cardiac energetics. Studies typically report the phosphocreatine (PCr) to adenosine triphosphate (ATP) ratio. We focus on another ³¹P signal: inorganic phosphate (Pi), whose chemical shift allows computation of myocardial pH, with Pi/PCr providing additional insight into cardiac energetics. Pi is often obscured by signals from blood 2,3‐diphosphoglycerate (2,3‐DPG). We introduce a method to quantify Pi in 14 min without hindrance from 2,3‐DPG.

Methods

Using a ³¹P stimulated echo acquisition mode (STEAM) sequence at 7 Tesla that inherently suppresses signal from 2,3‐DPG, the Pi peak was cleanly resolved. Resting state UTE‐chemical shift imaging (PCr/ATP) and STEAM ³¹P‐MRS (Pi/PCr, pH) were undertaken in 23 healthy controls; pH and Pi/PCr were subsequently recorded during dobutamine infusion.

Results

We achieved a clean Pi signal both at rest and stress with good 2,3‐DPG suppression. Repeatability coefficient (8 subjects) for Pi/PCr was 0.036 and 0.12 for pH. We report myocardial Pi/PCr and pH at rest and during catecholamine stress in healthy controls. Pi/PCr was maintained during stress (0.098 ± 0.031 [rest] vs. 0.098 ± 0.031 [stress] P = .95); similarly, pH did not change (7.09 ± 0.07 [rest] vs. 7.08 ± 0.11 [stress] P = .81). Feasibility for patient studies was subsequently successfully demonstrated in a patient with cardiomyopathy.

Conclusion

We introduced a method that can resolve Pi using 7 Tesla STEAM ³¹P‐MRS. We demonstrate the stability of Pi/PCr and myocardial pH in volunteers at rest and during catecholamine stress. This protocol is feasible in patients and potentially of use for studying pathological myocardial energetics.

Regional adiposity and heart failure with preserved ejection fraction

The role of obesity in the pathogenesis of heart failure (HF), and in particular HF with preserved ejection fraction (HFpEF), has drawn significant attention in recent years. The prevalence of both obesity and HFpEF has increased worldwide over the past decades and when present concomitantly suggests an obese-HFpEF phenotype. Anthropometrics, including body mass index, waist circumference, and waist-to-hip ratio, are associated with incident HFpEF. However, the cardiovascular effects of obesity may actually be driven by the distribution of fat, which can accumulate in the epicardial, visceral, and subcutaneous compartments. Regional fat can be quantified using non-invasive imaging techniques, including computed tomography, magnetic resonance imaging, and dual-energy X-ray absorptiometry. Regional variations in fat accumulation are associated with different HFpEF risk profiles, whereby higher epicardial and visceral fat have a much stronger association with HFpEF risk compared with elevated subcutaneous fat. Thus, regional adiposity may serve a pivotal role in the pathophysiology of HFpEF contributing to decreased cardiopulmonary fitness, impaired left ventricular compliance, upregulation of local and systemic inflammation, promotion of neurohormonal dysregulation, and increased intra-abdominal pressure and vascular congestion. Strategies to reduce total and regional adiposity have shown promise, including intensive exercise, dieting, and bariatric surgery programmes, but few studies have focused on HFpEF-related outcomes among obese. Further understanding the role these variable fat depots play in the progression of HFpEF and HFpEF-related hospitalizations may provide therapeutic targets in treating the obese-HFpEF phenotype.

Use of cardiac magnetic resonance to detect changes in metabolism in heart failure

The heart has a massive adenosine triphosphate (ATP) requirement, produced from the oxidation of metabolic substrates such as fat and glucose. Magnetic resonance spectroscopy offers a unique opportunity to probe this biochemistry: ³¹Phosphorus spectroscopy can demonstrate the production of ATP and quantify levels of the transport molecule phosphocreatine while 13Carbon spectroscopy can demonstrate the metabolic fates of glucose in real time. These techniques allow the metabolic deficits in heart failure to be interrogated and can be a potential future clinical tool.

Hemodynamic and Functional Impact of Epicardial Adipose Tissue in Heart Failure With Preserved Ejection Fraction

OBJECTIVES

This study determined the impact of excess epicardial adipose tissue (EAT) in patients with the obese phenotype of heart failure with preserved ejection fraction (HFpEF).

BACKGROUND

Patients with HFpEF and an elevated body mass index differ from nonobese patients, but beyond generalized obesity, fat distribution may be more important. Increases in EAT are associated with excess visceral adiposity, inflammation, and cardiac fibrosis, and EAT has been speculated to play an important role in the pathophysiology of HFpEF, but no study has directly evaluated this question.

METHODS

Patients with HFpEF and obesity (n = 169) underwent invasive hemodynamic exercise testing with expired gas analysis and echocardiography. Increased EAT was defined by echocardiography (EAT thickness ≥9 mm).

RESULTS

Compared with obese patients without increased EAT (HFpEF_EAT-, n = 92), obese patients with HFpEF with increased EAT (HFpEF_EAT+; n = 77) displayed a higher left ventricular eccentricity index, indicating increased pericardial restraint, but similar resting biventricular structure and function. In contrast, hemodynamics were more abnormal in patients with HFpEF_EAT+, with higher right atrial, pulmonary artery, and pulmonary capillary wedge pressures at rest and during exercise compared with those of patients with HFpEF_EAT-. Peak oxygen consumption (VO₂) was reduced in both groups but was 20% lower in patients with HFpEF_EAT+ (p < 0.01).

CONCLUSIONS

Among patients with the obese phenotype of HFpEF, the presence of increased EAT is associated with more profound hemodynamic derangements at rest and exercise, including greater elevation in cardiac filling pressures, more severe pulmonary hypertension, and greater pericardial restraint, culminating in poorer exercise capacity. Further study is needed to understand the biology and treatment of excessive EAT in patients with HFpEF.

Obesity Phenotypes, Diabetes, and Cardiovascular Diseases

This review addresses the interplay between obesity, type 2 diabetes mellitus, and cardiovascular diseases. It is proposed that obesity, generally defined by an excess of body fat causing prejudice to health, can no longer be evaluated solely by the body mass index (expressed in kg/m²) because it represents a heterogeneous entity. For instance, several cardiometabolic imaging studies have shown that some individuals who have a normal weight or who are overweight are at high risk if they have an excess of visceral adipose tissue-a condition often accompanied by accumulation of fat in normally lean tissues (ectopic fat deposition in liver, heart, skeletal muscle, etc). On the other hand, individuals who are overweight or obese can nevertheless be at much lower risk than expected when faced with excess energy intake if they have the ability to expand their subcutaneous adipose tissue mass, particularly in the gluteal-femoral area. Hence, excessive amounts of visceral adipose tissue and of ectopic fat largely define the cardiovascular disease risk of overweight and moderate obesity. There is also a rapidly expanding subgroup of patients characterized by a high accumulation of body fat (severe obesity). Severe obesity is characterized by specific additional cardiovascular health issues that should receive attention. Because of the difficulties of normalizing body fat content in patients with severe obesity, more aggressive treatments have been studied in this subgroup of individuals such as obesity surgery, also referred to as metabolic surgery. On the basis of the above, we propose that we should refer to obesities rather than obesity.

Extreme Obesity is Associated with Low Success Rate of Atrial Fibrillation Catheter Ablation

BACKGROUND

Catheter ablation (CA) is an established treatment for patients with symptomatic atrial fibrillation (AF). The purpose of this study was to evaluate the safety and efficacy of single CA in AF patients with extreme obesity (body mass index [BMI] ≥ 40 kg/m2) and its long-term impact on body weight.

METHODS

Patients with BMI ≥40 kg/m2 who underwent CA at the Ohio State University between 2012 and 2016 were included. The primary efficacy endpoint was no atrial arrhythmia lasting > 30 seconds without anti-arrhythmic drugs during 1-year follow-up after a single procedure.

RESULTS

Out of 230 AF patients with BMI ≥ 40 kg/m2 undergoing CA, pulmonary vein isolation was achieved in 226 (98%) patients.Seventeen patients (7.4%) experienced acute major complications, including pericardial effusion, vascular complications and respiratory failure. Patient characteristics for 135 patients with complete 1-year follow-up were as follows: mean age 58.6 ± 9.6 years, mean BMI 44.5±4.7 kg/m2, female 63 (47%), non-paroxysmal AF 100 (74%), median CHA2DS2-VASc score 2 (IQR:1-3). In this cohort, the primary efficacy endpoint was achieved in 44 (33%) patients. Paroxysmal AF was associated with higher CA success compared to non-paroxysmal (51 vs. 26% [p < 0.01]).There was no significant weight change even in patients with successful AF CA.

CONCLUSIONS

Extreme obesity is associated with low AF CA success, particularly in those with non-paroxysmal AF. Successful AF CA was not associated with long-term weight reduction. A better treatment strategy is needed in this population of AF and extreme obesity.

Obesity and Mechanisms of its Negative Impact on the Cardiovascular System

Currently, the number of obese people in the world is constantly increasing. Obesity has a direct negative impact on the heart and blood vessels, which can be considered not only as an appropriate response to an increase in the volume of circulating blood due to an increase in body weight, but also as a side tissue reaction of the myocardium to hormonal and metabolic changes inherent in obesity. Our review is devoted to the description of the mechanisms of influence of obesity on the structural and functional parameters of the heart, which create prerequisites for the development of cardiovascular diseases, as well as the existing contradictions. Currently, the accumulated data suggest that an excessive amount of adipose tissue, in addition to metabolic disorders, including insulin resistance, imbalance of adipokines and inflammation markers, leading to the development of lipotoxicity, can directly penetrate the myocardium and cause violations of its contractile properties, as well as affect the conduction of excitation pulses and provoke the development of rhythm and conduction disorders. The development of endothelial dysfunction in obesity ultimately leads to the development of atherosclerosis and coronary heart disease. In addition, obesity contributes to the emergence of risk factors for hypertension, diabetes, atrial fibrillation, chronic heart failure, obstructive sleep apnea syndrome. Given the differences in the literature on the effect of obesity on long-term outcomes in patients with cardiovascular diseases, it is important to conduct prospective studies on the role of individual factors and their combinations that affect the mortality of patients with cardiovascular diseases.

Myocardial adipose deposition and the development of heart failure with preserved ejection fraction

AIMS

It has been proposed that an increase of myocardial adiposity is related to left ventricular (LV) diastolic dysfunction. The specific roles of myocardial steatosis including epicardial fat and intramyocardial fat for diastolic function are unknown in those patients suffering heart failure (HF) with reduced (HFrEF) or preserved ejection fraction (HFpEF). This study aims to determine the complex relationship between myocardial adiposity in patients with HFrEF or HFpEF.

METHODS AND RESULTS

Using cardiac magnetic resonance imaging (CMRI), myocardial steatosis was measured in 305 subjects (34 patients with HFrEF, 163 with HFpEF, and 108 non-HF controls). We also evaluated cardiac structure and diastolic and systolic function by echocardiography and CMRI. Patients with HFpEF had significantly more intramyocardial fat than HFrEF patients or non-HF controls [intramyocardial fat content (%), 1.56 (1.26, 1.89) vs. 0.75 (0.50, 0.87) and 1.0 (0.79, 1.15), P < 0.05]. Intramyocardial fat amount (%) was higher in HFpEF women than in men [1.91% (1.17%, 2.32%) vs. 1.22 (0.87%, 2.02%), P = 0.01]. When estimated by CMRI (left ventricular peak filling rate), echocardiographic E/e' level, or left atrial volume index, intramyocardial fat correlated with LV diastolic dysfunction parameters in HFpEF patients, and this was independent of age, co-morbidities, body mass index, gender, and myocardial fibrosis (standardized coefficient: β = -0.34, P = 0.03; β = 0.29, P = 0.025; and β = 0.25, P = 0.02, respectively).

CONCLUSIONS

Patients with HFpEF had significantly more intramyocardial fat than HFrEF patients or non-HF controls. Independent of risk factors or gender, intramyocardial fat correlated with LV diastolic dysfunction parameters in HFpEF patients.

Epicardial Adipose Tissue and Cardiovascular Disease

PURPOSE OF REVIEW

Epicardial adipose tissue has been associated with the development/progression of cardiovascular disease. We appraise the strength of the association between epicardial adipose tissue and development/progression of cardiovascular diseases like coronary artery disease, atrial fibrillation, and heart failure with preserved ejection fraction.

RECENT FINDINGS

Cross-sectional clinical and translational correlative studies have established an association between epicardial adipose tissue and progression of coronary artery disease. Recent studies question this association and underline the need for longitudinal studies. Epicardial adipose tissue also plays a definite role in the pathobiology of atrial fibrillation and its recurrence after ablation. In contrast to an early paradigm, epicardial adipose tissue does not appear to play a key role in the pathogenesis of heart failure with preserved ejection fraction in obese patients. The association of epicardial adipose tissue with atrial fibrillation is robust. In contrast, the association of epicardial adipose tissue with coronary artery disease and heart failure with preserved ejection fraction is tenuous. Additional research, including longitudinal studies, is needed to confirm or refute these proposed associations.

Late effects of pediatric hematopoietic stem cell transplantation on left ventricular function, aortic stiffness and myocardial tissue characteristics

BACKGROUND

Pediatric hematopoietic stem cell transplantation (HSCT) recipients are at increased risk of cardiovascular disease later in life. As HSCT survival has significantly improved, with a growing number of HSCT indications, tailored screening strategies for HSCT-related late effects are warranted. Little is known regarding the value of cardiovascular magnetic resonance (CMR) for early identification of high-risk patients after HSCT, before symptomatic cardiovascular disease manifests. This study aimed to assess CMR-derived left ventricular (LV) systolic and diastolic function, aortic stiffness and myocardial tissue characteristics in young adults who received HSCT during childhood.

METHODS

Sixteen patients (22.1 ± 1.5 years) treated with HSCT during childhood and 16 healthy controls (22.1 ± 1.8 years) underwent 3 T CMR. LV systolic and diastolic function were measured as LV ejection fraction (LVEF), the ratio of transmitral early and late peak filling rate (E/A), the estimated LV filling pressure (E/Ea) and global longitudinal and circumferential systolic strain and diastolic strain rates, using balanced steady-state free precession cine CMR and 2D velocity-encoded CMR over the mitral valve. Aortic stiffness, myocardial fibrosis and steatosis were assessed with 2D velocity-encoded CMR, native T1 mapping and proton CMR spectroscopy (1H-CMRS), respectively.

RESULTS

In the patient compared to the control group, E/Ea (9.92 ± 3.42 vs. 7.24 ± 2.29, P = 0.004) was higher, LVEF (54 ± 6% vs. 58 ± 5%, P = 0.055) and global longitudinal strain (GLS) ( -20.7 ± 3.5% vs. -22.9 ± 3.0%, P = 0.063) tended to be lower, while aortic pulse wave velocity (4.40 ± 0.26 vs. 4.29 ± 0.29 m/s, P = 0.29), native T1 (1211 ± 36 vs. 1227 ± 28 ms, P = 0.16) and myocardial triglyceride content (0.47 ± 0.18 vs. 0.50 ± 0.13%, P = 0.202) were comparable. There were no differences between patients and controls in E/A (2.76 ± 0.92 vs. 2.97 ± 0.91, P = 0.60) and diastolic strain rates.

CONCLUSION

In young adults who received HSCT during childhood, LV diastolic function was decreased (higher estimated LV filling pressure) and LV systolic function (LVEF and GLS) tended to be reduced as compared to healthy controls, whereas no concomitant differences were found in aortic stiffness and myocardial tissue characteristics. When using CMR, assessment of LV diastolic function in particular is important for early detection of patients at risk of HSCT-related cardiovascular disease, which may warrant closer surveillance.

Very low calorie diets are associated with transient ventricular impairment before reversal of diastolic dysfunction in obesity

Objectives

Very low calorie diets (VLCDs) are effective at clearing hepatic steatosis and improving insulin sensitivity. Whilst long-term weight loss is beneficial to the cardiovascular system, the acute elevation in fatty acids during caloric restriction is potentially detrimental to cardiac metabolism and function. We sought to investigate any cardiovascular changes occurring over the course of a modern VLCD regime, alongside the expected peripheral metabolic improvements.

Methods

25 obese volunteers (BMI 36.8 ± 5.8 kg/m²) underwent magnetic resonance imaging, echocardiography, metabolic profiling, and bio-impedance analysis before 1 and 8 weeks following a VLCD (800 kcal/day). Results were compared to 15 age- and sex-matched controls.

Results

After 1 week of VLCD, despite only modest weight loss, significant drops occurred in liver fat and insulin resistance (HOMA-IR; by 14–50%, all p < 0.01). In contrast, myocardial triglyceride content (MTGC) increased (by 48%, p = 0.030), and was associated with deterioration in both systolic (LVEF by 4%, p = 0.041) and diastolic function (e/e′ 8.6 ± 1.4 to 9.4 ± 1.7, p = 0.019). Aortic stiffness also increased by 35% (p = 0.015).

At 8 weeks, liver steatosis and visceral fat were lower than baseline (by 20–55%, p < 0.001), and peripheral metabolic improvements continued. MTGC also fell to below baseline (1.5 ± 0.6 vs 2.1 ± 1%, p = 0.05) with improved myocardial function (e/e′ 8.6 ± 1.4 to 7.5 ± 1.5, p = 0.003).

Conclusions

Whilst VLCDs result in dramatic improvements in insulin resistance, they are associated with transient but significant cardiovascular functional decline, which may have an impact on those with the coexisting cardiac disease. However, after 8 weeks, the diet was associated with normalisation of cardiac function, suggesting they may form a potential therapeutic intervention for diastolic dysfunction in obesity and diabetes.

Association of body mass index and diastolic function in metabolically healthy obese with preserved ejection fraction

BACKGROUND

Small scale cohorts demonstrated an association between body mass index (BMI) and diastolic function in a metabolically healthy population. We aimed to characterize the relation between BMI and diastolic function in a relatively large cohort of metabolically healthy obese with preserved ejection fraction.

METHODS AND RESULTS

Echocardiograms of metabolically healthy patients between 2011 and 2016, who had no significant valvulopathies or atrial fibrillation, and had preserved ejection fraction, were retrospectively identified and analyzed. Metabolically healthy was defined as lack of known diabetes mellitus, hypertension, and hyperlipidemia. Patients were categorized into 4 groups according to BMI - normal BMI 18.5-25, overweight 25.01-30, obese 30.01-35, morbidly obese >35 kg/m². The cohort consisted of 7057 individuals, 54.9% males, with a mean age 54 years. Patients in higher BMI groups more commonly demonstrated abnormalities in most echocardiographic parameters associated with diastolic dysfunction, including left atrial volume index>34 ml/m², E/e'>14, e' lateral<10 cm/s, e' septal<7 cm/s, tricuspid regurgitation velocity>2.8 m/s and systolic pulmonary artery pressure≥36 mmHg (p<0.01 for all comparisons). Morbidly obese carried the highest risk compared to those with normal BMI. There were no significant differences between the groups in rates of readmission due to heart failure.

CONCLUSION

High BMI is associated with increased risk of diastolic dysfunction even in metabolically healthy patients. Additional trials are needed in order to evaluate whether these echocardiographic findings translate into clinical implications.