Abstract 4139170: Relationship between hemodynamics and oxygen consumption in hypertrophic cardiomyopathy during maximal stress testing

Circulation, Volume 150, Issue Suppl_1, Page A4139170-A4139170, November 12, 2024. Background:Hypertrophic cardiomyopathy (HCM) is a global heart disease with great variability in disease severity, which can lead to significant impairment of exercise capacity. In healthy populations, oxygen consumption is related to cardiac output and arteriovenous oxygen difference. We sought to determine the relationship between hemodynamics (cardiac output and stroke volume) and oxygen consumption in HCM compared to healthy controls during maximal stress testing.Aims:To evaluate associations between the trajectories of hemodynamic function and oxygen consumption in HCM compared to healthy controls.Methods:Twenty individuals with HCM (51±15 years old, body mass index (BMI): 28±3 kg/m2, females, n=4) and 16 healthy controls (66±7 years old, 27±6 kg/m2, females, n=6) were included in the present study. Participants completed a maximal-graded stress test coupled with non-invasive hemodynamic bioreactance (cardiac output, stroke volume) and gas exchange (oxygen consumption, VO2) measurements. Data were analyzed in quartiles (exercise only) and phases (rest, pre-pedalling, exercise and recovery) of the maximal-graded stress test.Results:In HCM, cardiac output declined in the fourth quartile of the exercise phase of the stress test (-0.39 L/min,p

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Novembre 2024

Abstract 4140185: The Burden Of Substance Abuse And Mental Health Disorders In Patients Admitted With Stress Cardiomyopathy

Circulation, Volume 150, Issue Suppl_1, Page A4140185-A4140185, November 12, 2024. Introduction:Several studies have linked mental health disorders and substance abuse as risk factors for stress cardiomyopathy (SC). However, the true burden of these disorders amongst patients with stress cardiomyopathy remains unknown.Methods:We used the 2016-2020 National Inpatient Sample database to identify hospitalizations for SC who underwent diagnostic catheterization. We assessed the proportion of patients diagnosed with a substance abuse or mental health disorder. Subsequently, the association of these disorders in SC compared to patients admitted for myocardial infarction (MI) was assessed using the chi-square test.Results:From 2016 to 2020, there were 33,075 hospitalizations for stress cardiomyopathy who were diagnosed by cardiac catheterization. Of these patients, 5,920 (17.9 %) had depression, 8,500 (25.7 %) had anxiety, 1058 (3.2 %) had severe stress reactions, and 16,372 (49.5 %) were diagnosed with a mental health disorder. 9,955 (30.1 %) were smokers, 5,358 (16.2%) abused hallucinogens, 5,457 (16.5 %) abused cocaine, 5,457 (16.5%) abused sedatives, 6,019 (18.2 %) abused cannabis, 5,920 (17.9%) abused opioids, 6,416 (19.4 %) abused alcohol. Subsequently, the association of stress cardiomyopathy with mental and substance abuse disorder was compared with patients admitted with myocardial infarction See Table 1.Conclusion:Mental health and substance abuse disorders are common in patients diagnosed with SC. These disorders are more commonly present in SC compared to MI. Further research is needed to assess the significance of these findings.

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Novembre 2024

Abstract 4147602: The Paradox Role of Sirtuin 6 In Coronary Microvascular Function under Metabolic Stress

Circulation, Volume 150, Issue Suppl_1, Page A4147602-A4147602, November 12, 2024. Coronary microvascular dysfunction (CMD), which is associated with diabetic cardiomyopathy, Takotsubo cardiomyopathy, andheart failure with preserved ejection fraction (HFpEF), is understudied. CMD is characterized by impaired endothelial-dependent vasodilation, but detailed mechanisms have yet to be elucidated.Nuclear Sirtuin 6 (SIRT6) plays essential roles in gene transcriptional, stress tolerance, DNA repair, inflammation, and aging. SIRT6 is strongly associated with cardiovascular pathologies, but how SIRT6 regulates endothelial metabolisms and homeostasis under metabolic stress and the underlying mechanism remains poorly understood. It might be because global Sirt6 knockout mice are perinatally lethal caused by hypoglycemia, suggesting the essential role of SIRT6 in glucose metabolism.In our preliminary studies, we generated inducible global Sirt6 knockout mice by crossing with Sirt6 f/f mice with CAG-cre (Sirt6f/f, CAG), and mice were viable with normal glucose levels. However, they showed impaired endothelial-dependent dilation (EDD) and impaired coronary flow reserve (CFR), an index clinically used to diagnose CMD. It suggests that deletion of Sirt6 might cause EC dysfunction because Sirt6 is reported to protect EC from premature senescence and oxidative stress by sustaining high eNOS levels. Surprisingly, when we studied non-inducible Sirt6 endothelial-specific knockout (Sirt6f/f, tie-2 cre) and inducible Sirt6 endothelial-specific knockout (Sirt6 f/f,Cdh5-cre/ERT2) and wild-type (WT) mice, Sirt6f/f, Tie-2and Sirt6f/f, Cadh5mice do not phenocopy the inducible global SIRT6 knockout mice, they had normal EDD and CFR. When the mice were fed a high fat and high sugar (HFHS) diet, the Sirt6f/f, Tie-2and Sirt6f/f, Cadh5had impaired EDD, suggesting Sirt 6 functioned differently in the mice fed with chow diet or HFHS diet.We hypothesize Sirt 6 deficiency causes coronary endothelial dysfunction and contributes to CMD; activating Sirt6 will ameliorate CMD. EDD was assessed using myography (DMT). Myocardial blood flow (MBF) was measured by Doppler. Our preliminary data show that the mediator of coronary vasodilation switched from NO to H2O2in the Sirt6 knockout mice with impaired EDD. Interestingly, when the mice fed on HFHS were treated with Sirt 6 activator MDL-800, the coronary microvascular function was improved, and the blood glucose level was decreased. The underlying mechanism and the pathways involved will be elucidated.

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Novembre 2024

Abstract 4114705: Clinical Predictors of Stress Induced Cardiomyopathy

Circulation, Volume 150, Issue Suppl_1, Page A4114705-A4114705, November 12, 2024. Introduction:Stress Induced Cardiomyopathy is increasingly becoming more prevalent with increasing awareness about disease condition with annual incidence of 30 cases/100000 per year and an incidence of 1-2% in the patients presenting with acute coronary syndrome.[1] Physical and emotional triggers have been linked with occurrence of Stress induced Cardiomyopathy.Methods:We have obtained the National Readmission database for the year of 2020. We have used the ICD 10 code I51.81 for stress induced cardiomyopathy and found 10450 patients in the data base. Total 494 patients had cardiac arrest and 191 patients out of this 494 had died. We have used Binary logistic regression methods to find the odd ratio for physical and emotional risk factors for stress induced cardiomyopathy.Results:Grief disorder with an odd ratio of 7.2, followed by female gender with an odd ratio of 4.1, septic shock with an odd ratio of 3.3, Hemorrhagic stroke with an odd ratio of 1.73, ischemic stroke with an odd ratio of 1.72, depression with an odd ratio of 1.5, followed by asthma exacerbation with an odd ratio of 1.35 and seizure disorder with an odd ratio of 1.34 were among the few predictors for stress induced cardiomyopathy. Incidence of Cardiac Arrest was 4.7% and mortality rate of 1.8% was observed in the patients with stress induced Cardiomyopathy.Discussion:Extreme emotional and physical triggers like stroke, septic shock are among few significant risk factors for the stress induced cardiomyopathy.

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Novembre 2024

Abstract 4141446: Sodium Glucose Co-transporter 2 (SGLT2) Inhibitors Promote Resiliency to High Pressure Stress in the Human Microvasculature

Circulation, Volume 150, Issue Suppl_1, Page A4141446-A4141446, November 12, 2024. Emerging evidence suggests that vascular stress from cardiovascular-related co-morbidities promotes microvascular dysfunction, a key component in the development of heart failure with preserved ejection fraction. The sodium glucose co-transporter 2 (SGLT2) inhibitor empagliflozin has been shown to reduce both morbidity and mortality associated with heart failure with preserved ejection fraction, however the full scope of influence of this therapy on human microvascular function remains unknown. We hypothesized that pre-treatment of isolated human microvessels with empagliflozin will prevent stress-induced endothelial dysfunction as evidenced by preserving both the magnitude of flow-induced dilation (FID) as well as the ability to dilate to nitric oxide. Human resistance arterioles (80-250µm) from healthy adults (defined as patients with ≤1 risk factor for cardiovascular disease) were dissected from discarded surgical adipose tissue and treated with empagliflozin (1µM), or vehicle control (ethanol) for 16-20 hours prior to the flow experiment. Vessels were cannulated for videomicroscopy and subjected to high intraluminal pressure (150mmHg, 30 min), an acute stress known to induce endothelial dysfunction. Vessels were pre-constricted with endothelin-1 prior to initiation of flow. A nonlinear logistic regression was used to determine differences between curves. Compared to vehicle control, vessels pre-treated with empagliflozin (1µM ) exhibited nitric oxide-dependent FID as dilation was impaired in the presence of the nitric oxide synthase inhibitor L-NAME (EC50 Control: 10.7 vs L-NAME 83.45, p=0.0107). This data suggests that empagliflozin, an SGLT2 inhibitor, promotes microvascular resilience to stress via preservation of nitric oxide-mediated FID. The ability to elicit stress resilience may explain in part some of the cardiovascular benefits associated with SGLT2 inhibitors and may offer unique opportunities for early intervention or prevention of microvascular dysfunction associated with comorbidities that contribute to heart failure with preserved ejection fraction.

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Novembre 2024

Abstract 4146301: Relationship Between Calf Muscle Pump Function and Exercise Stress Testing

Circulation, Volume 150, Issue Suppl_1, Page A4146301-A4146301, November 12, 2024. Background:Exercise stress testing uses metabolic equivalents of tasks (METs) to measure the energy cost of activities, aiding in the assessment of exercise capacity and cardiovascular health. Despite its significance, the correlation between calf muscle pump function (CPF) and exercise stress testing remains unexplored. We aimed to evaluate the relationship between CPF and peak METs as determined by cardiopulmonary treadmill exercise stress testing.Methods:The study included adults who underwent exercise cardiopulmonary stress testing and venous plethysmography at Mayo Clinic between April 2017 and March 2020. The protocols other than Bruce, Mayo, Modified Naughton, and Naughton protocols were excluded. The CPF ejection fraction (EF) was calculated per leg based on refill volumes post-exercise as a percentage of passive drain refill. The classification of CEAP (Clinical-Etiology-Anatomy-Pathophysiology) was utilized to better understand chronic venous insufficiency (CVI).Results:A total of 155 patients who underwent both exercise stress testing and venous plethysmography were included, with a mean age of 61.31 ± 14.03 years, and 84 (54.2%) were male. The peak measured METs for normal, unilaterally reduced, and bilaterally reduced CPF were 8.5 (2.5), 7.3 (2.1), and 7.1 (2.4), respectively (p=0.004, Figure 1). Multiple linear regression models were developed with METs as the outcome to determine if CPF was an independent predictor of METs on cardiopulmonary exercise stress testing. IIn model 1, the following independent variables were included: resting heart rate, peak heart rate, peak systolic blood pressure, recovery heart rate at minute 1, and worst EF (Table 1). In model 1, with only exercise parameters, lower EF was associated with lower METs (p=0.03). In a second analysis, variables identified as statistically significant with METs in the initial model were included, along with CEAP class (model 2) and CCI (model 3) (Table 2). In model 2, CEAP class 3 or higher was associated with decreased METs on the exercise stress test. This correlation implies that individuals with moderate to severe CVI may influence exercise capacity, demonstrating the interconnectedness of the cardiovascular system. Moreover, in model 3, the CCI, a predictor for mortality, was not significantly associated with METs.Conclusion:Our findings revealed that more severe CVI (CEAP class and reduced CPF) was associated with reduced exercise capacity after accounting for other factors.

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Novembre 2024

Abstract 4146434: Factors Associated with Subsequent Catheterization and Identification of High-Grade Obstructive Coronary Artery Disease in Patients Without Known Coronary Disease and a Low to Moderate Short-Term Risk PET/CT Stress Test

Circulation, Volume 150, Issue Suppl_1, Page A4146434-A4146434, November 12, 2024. Background:PET/CT stress test may be performed to risk stratify patients including those without known coronary artery disease (CAD) who may be at risk for short-term adverse cardiac events. In patients with low- to moderate (LTM) risk for short-term MACE and without a known history of CAD, a small percentage of these patients will undergo a coronary angiogram within 90-days, of which some will be diagnosed with high-grade stenosis. The purpose of this study is to determine factors associated with this approach and findings.Methods:Patients without a history of known CAD (n=43,271) undergoing a PET/CT from 2018-2023 at Intermountain Health, with scan interpreted clinically as LTM short-term risk for adverse cardiac events, and ischemic burden 70% stenosis in any vessel), an a priori list of clinical data and PET/CT results were examined.Results:Within 90 days of the LTM risk PET/CT, 3,163 (8.2%) had a coronary angiogram. Of these, 806 (25.5% of angiograms and 2.1% of total LTM) had high-grade CAD. The PET/CT ancillary findings were associated with the largest odds of performing an angiogram and the presence of high-grade CAD (Tables). Factors most likely to be associated with performing an angiogram were an ischemic burden of 7.5-10% (adjusted-OR [adj. OR]=11.54), coronary artery calcification (CAC) score of >300 (adj.-OR =1.62), and myocardial blood flow (MBF) of MBF 2.3). Other clinical parameters associated, after adjustment, with an angiogram were age, male sex, hypertension, elevated troponin, and inpatient status. Many of the same factors were found to be associated with the identification of high-grade CAD. However, being an inpatient was associated with increased odds of angiogram but a decrease in odds of high-grade CAD.Conclusions:In patients without a known history of CAD who underwent PET/CT clinically adjudicated as LTM short-term risk and ischemic burden

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Novembre 2024

Abstract 4141357: Diagnostic and prognostic value of quantitative stress perfusion CMR in the non-invasive assessment of cardiac allograft vasculopathy

Circulation, Volume 150, Issue Suppl_1, Page A4141357-A4141357, November 12, 2024. Background:Cardiac allograft vasculopathy (CAV) is a rapidly progressive form of coronary atherosclerosis limiting long-term survival after heart transplantation.Objectives:We evaluated the diagnostic and prognostic yield of quantitative stress cardiovascular magnetic resonance (CMR) perfusion for CAV detection in heart transplant recipients.Methods:Patients who received orthotopic heart transplants and underwent stress CMR for CAV assessment were included in the study and followed up for almost 2 years (median 1.8; IQR 0.9,2.7). The diagnostic accuracy of qualitative and quantitative stress CMR was assessed by calculating sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), using invasive or CT coronary angiography as the reference for CAV detection. The area under the curve (AUC) was compared for qualitative and quantitative stress CMR. Adjusted hazard ratios for major adverse cardiac events (MACE), including death and unplanned cardiac hospitalizations were derived in all patients. The global myocardial perfusion reserve index (MPRi) was obtained by normalization to the rate-pressure product.Results:In a cohort of 60 patients, n=18 (30%) had significant CAV (grade 2 or 3), and n=11 (18.3%) experienced MACE. At the Youden index threshold of 2.1, the myocardial perfusion reserve index (MPRi) demonstrated a sensitivity of 85.7%, a specificity of 70.3%, a PPV of 52.2%, and an NPV of 92.9%. The MPRi was significantly more accurate than visual assessment (p < 0.001) in identifying underlying CAV (Figure 1) and it was an independent predictor of MACE (HR:0.26;95%CI:0.07,0.93; log-rank p=0.022; Figure 2), while the visual presence of inducible myocardial perfusion defect did not (HR:2.23;95%CI:0.57,8.66; p=0.2).Conclusions:In patients with previous heart transplantation, quantitative stress CMR perfusion has incremental diagnostic and prognostic value over qualitative stress CMR for the non-invasive detection of CAV.

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Novembre 2024

Abstract 4145256: Urban Greenspace Exposure, Stress, and Cardiovascular Function.

Circulation, Volume 150, Issue Suppl_1, Page A4145256-A4145256, November 12, 2024. Introduction:Healthy urban environments are essential for improving cardiovascular health. Although exposure to wild green surroundings has been shown to have positive effects on mental and physical health, the effect of urban greenspaces on cardiovascular function and stress remain unclear.Research Question:Does being in an urban park decrease stress and autonomic tone as reflected by heart rate variability (HRV).Methods:We invited healthy adults (n=41; age 25-70 years) to participate in a cross-over panel study. They were randomly assigned to start in either a typical urban park or an adjacent urban space, spending 20min sitting and 20min walking. Self-reported distress and State-Trait Anxiety Index (STAI) scales were assessed before and after exposure. Pairedt-test was used to compare stress levels by site, and the effect size was calculated using regression analysis after adjusting for the level of starting distress. ECG recordings were acquired for the duration of the visit. HRV epochs of 5 min at the end of sitting or walking period and 40 min for the entire study were analyzed and compared using pairedt-test.Results:Pre-exposure distress and STAI summed scores were similar for the park and built spaces, but the level of distress was lower after visiting the park compared with built space (19.6±15.0 vs. 24.1±12.1; p=0.05). STAI scores were decreased after visiting the park, but not the built space (-5.4±8.2 vs. 0.8±6.8; p=0.003). When adjusted for the starting levels of distress, the summed STAI score after visiting the park was reduced by 6 (-10.34, -2.11), but no change for the built site. The standard deviation of NN intervals (SDNN) was higher in the park than the urban site (41.7 vs. 37.3; p=0.03) and the HR was lower (78 vs. 81; p=0.01) across the entire study epoch (40min). There was no significant change during the seated portion of visits, but across the walking portion, the values of SDNN were higher in greenspace (32.2 vs. 27.0; p= 0.01) and HR was lower (87 vs 84; p=0.02). Other HRV indices were not significantly affected.Conclusion:Visiting an urban park, but not a built environment, led to a decrease in self-reported distress, and a relative shift in the autonomic nervous system towards parasympathetic dominance. Although the relationship between changes in stress and HRV remain unclear, access to greenspaces may be an important factor in maintaining and enhancing cardiovascular health in urban environments.

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Novembre 2024

Abstract 4143420: Additive Prognostic Significance of Vascular Disease in Patients Referred for Exercise Stress Echocardiography

Circulation, Volume 150, Issue Suppl_1, Page A4143420-A4143420, November 12, 2024. Background:The presence of carotid plaque (CP) may serve as an indicator of panvascular atherosclerosis. However, the observed incongruity between carotid disease and the presence and severity of coronary artery disease (CAD) suggests differing mechanisms. We investigated the prognostic value of this incongruity, considering both known atherosclerosis and myocardial ischemia.Methods:In a retrospective analysis, we examined 111 patients (mean age: 64±12 years, 58% women) who underwent exercise stress echocardiography, with recent carotid artery and coronary evaluation. We computed a Vascular Disease (VasD) score, integrating the presence of carotid plaque (CP) on carotid ultrasound, known coronary artery disease (CAD), and myocardial ischemia (MyI). Subsequently, patients were followed for 5.5 years for mortality, coronary revascularization, and cardiac hospitalization.Results:During the follow-up period, 29 patients experienced the combined outcome (4 deaths, 10 revascularizations, and 22 hospitalizations). Among the cohort, 44 patients exhibited no vascular disease, while 67 displayed evidence of vascular disease, categorized as 42 with VasD of 1 (comprising 30 CP, 9 CAD, and 3 MyI), 14 with VasD of 2 (5 CP and CAD, 6 CP and MyI, 3 CAD and MyI), and 11 with VasD of 3. There were no significant differences between patients with and without VasD concerning sex, diabetes, renal function, atrial arrhythmia, baseline LVEF, and baseline diastolic function. However, patients with VasD were older, had higher H2FPEF scores, and lower exercise capacity, as well as elevated baseline and exercise-induced filling pressures. The incidence of the combined outcome showed a progressive increase with higher VasD scores (p

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Novembre 2024

Abstract 4146225: Stress Perfusion Cardiac Magnetic Resonance Imaging for Pediatric Patients with Repaired Transposition of the Great Arteries

Circulation, Volume 150, Issue Suppl_1, Page A4146225-A4146225, November 12, 2024. Introduction:Patients who underwent arterial switch operation (ASO) for d-transposition of the great arteries (TGA) are at increased risk for early myocardial ischemia. Stress perfusion cardiac MR (SPCMR) is used as a non-invasive tool for risk stratification but interpretation is often challenging.Hypothesis:There is significant interobserver variability in SPCMR image interpretation in patients with repaired TGA.Aims:1. Determine incidence and severity of adverse effects of stress agents.2. Evaluate incidence of positive SPCMR.3. Assess agreement amongst reviewers in image interpretation.Methods:Patients with repaired TGA with SPCMR imaging from 2013 to 2024 were reviewed. Three patients with previous coronary intervention and one with severe chest pain after adenosine, unable to complete SPCMR, were excluded. 61 studies were performed in 56 patients. Images were independently reviewed by two investigators blinded to initial interpretation and clinical outcome. Perfusion defects were displayed on a circumferential polar plot using standard LV segmentation.Results:Median (IQR) age was 15 (11-17) years, weight 55 (36-68) kg, and BSA 1.6 (1.2-1.8) m2. Max heart rate was 110 (100-125) and systolic BP 127 (116-138). Eleven (20%) patients had cardiac symptoms, chest pain in 9 (16%), syncope in 1 (2%), pallor and distress in 1 (2%) infant. Adverse effects from SPCMR in 8/52 (15%) adenosine, 2/4 (50%) dobutamine, and 0/6 (0%) regadenoson were minor and resolved on stress completion. Six (10%) studies were initially interpreted as suspicious (n=5) or definitive (n=1) perfusion defect (Figure). No LGE was detected. Original interpretation did not match blinded reviews for 6 cases (Figure). Blinded reviewers agreed on 3 negative cases but interpretation differed in the other 3 cases (Figure).Conclusions:SPCMR is safe and feasible. Significant interobserver variability highlights the challenges in qualitative SPCMR interpretation for TGA. Quantitative perfusion may reduce interobserver variability. Larger multicenter studies would be helpful in further elucidating the risk profile of patient characteristics and coronary artery arrangements to determine whether routine use of SPCMR is warranted for TGA patients.

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Novembre 2024

Abstract 4145229: Outcomes among hospitalized patients with stress-induced cardiomyopathy and concomitant Coronavirus Disease 2019 (COVID-19) infection: Insight from the US National Inpatient Sample

Circulation, Volume 150, Issue Suppl_1, Page A4145229-A4145229, November 12, 2024. Background:Stress-induced cardiomyopathy (CM) is a form of acute transient left ventricular dysfunction triggered by underlying physiological stress which often leads to increased morbidity and mortality. Coronavirus disease 2019 (COVID-19) is thought to cause stress-induced CM due to overwhelming systemic inflammation. There is paucity of data regarding the impact of COVID-19 on in-hospital outcomes of patients with stress-induced CM. The purpose of this study is to investigate in-hospital outcomes, including mortality and cardiogenic shock, of patients with concomitant COVID-19 and stress-induced CM.Methods:We queried the 2020 USA National Inpatient Sample (NIS) Database in conducting this retrospective cohort study. We identified hospitalized adult patients ≥ 18 years old with stress-induced CM and concomitant COVID-19 using ICD-10 CM codes. We used a survey multivariable logistic and linear regression analysis to calculate adjusted odds ratios (aORs) for outcomes of interest. A p value of

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Novembre 2024

Abstract 4141350: Endothelial-Mesenchymal Transition Mediated by Mechanical Stress Prompts Atrial Fibrogenesis

Circulation, Volume 150, Issue Suppl_1, Page A4141350-A4141350, November 12, 2024. Background:Atrial fibrosis is crucial in developing atrial fibrillation (AF). Elevated atrial pressure may significantly mediate atrial fibrosis, yet its underlying mechanisms remain unclear.Methods:Patients with AF who underwent radiofrequency ablation were recruited. Clinical data, including high-density mapping and imaging information, was analyzed. Multivariate regression analysis was performed to identify risk factors for low-voltage areas in the atrium. The CS-CREM mouse model, an autonomic AF model, was previously developed by our research group. Millar pressure catheters were used to measure left ventricular, right ventricular, and right atrial pressures in CS-CREM mice. Single-nucleus sequencing was employed to map the single-cell transcriptomes of atrial samples in CS-CREM and wild-type mice at different disease stages. Human primary atrial endocardial endothelial cells (ACCE) and HUVEC cell lines were subjected to mechanical stretch using the Flexcell tension system, followed by in vitro validation experiments. Mg101, a calpain inhibitor, was administered to CS-CREM mice for in vivo validation experiments.Results:Elevated atrial pressure in AF patients was identified as a significant risk factor for atrial fibrosis. Atrial pressure-related indices were linearly correlated with atrial fibrosis. Compared to wild-type mice, CS-CREM heterozygous mice exhibited significantly higher atrial pressure and aggravated atrial fibrosis. Single-nucleus sequencing revealed that atrial endocardial endothelial cells in CS-CREM mice underwent endothelial-mesenchymal transition (EnMT) into fibroblasts, with mechanical stress protein Flna being a critical regulatory protein. In vitro experiments demonstrated mechanical stretch-induced EnMT in ACCE and HUVEC cell lines. Mechanical stretch-activated mechanosensitive receptors on ACCE cell membranes led to increased intracellular calcium levels and calpain activation, which cleaved Flna into Flna 90. Flna 90 facilitated the nuclear translocation of transcription factor Smad3/7 and TGF-β, promoting the expressions of EnMT genes. This EnMT process was reversible with Mg101. In vivo experiments showed that Mg101 reduced the incidence of AF and mitigated atrial fibrosis in CS-CREM mice.Conclusion:Mechanical stress induces cleaved Flna 90 from Flna in atrial endocardial endothelial cells, thus assisting transcription factors Smad3/7 and TGF-β in nuclear translocation, regulating EnMT and mediating atrial fibrosis.

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Novembre 2024

Abstract 4138946: Psychological Stress and Risk of Heart Failure and Its Subtypes in the Women’s Health Initiative

Circulation, Volume 150, Issue Suppl_1, Page A4138946-A4138946, November 12, 2024. Background:Psychological stress affects cardiovascular (CV) health via multiple physiological and behavioral pathways. Few studies have assessed whether psychological stress impacts heart failure (HF) incidence. A prior large cohort study identified unique associations between perceived stress and HF subtype, but these associations were confounded by other health risk factors (e.g., prevalent baseline CV disease). No prospective study has evaluated these associations in women free of baseline CV disease.Goal:To evaluate the prospective association of psychological stress with incident HF and HF subtype risk in post-menopausal women.Hypothesis:Psychological stress is prospectively associated with an increased HF hospitalization risk, which may vary by HF type (HFpEF vs. HFrEF).Method:Of 29,703 post-menopausal women enrolled in the Women’s Health Initiative (WHI) free of baseline CV disease and pre-existing HF at first adjudication, psychological stress was assessed via an 11-item scale of stressful life events (SLE) over the past year (WHI screening, 1993-1998) and the 4-item Perceived Stress Scale (PSS; WHI Extension 2, 2010-2015). Incident HF was confirmed via adjudication of self-reported first hospitalization. Cox proportional hazards models adjusting for demographic, medical, and lifestyle factors were used to calculate hazard ratios associating stress quartiles with incident HF, HFpEF, and HFrEF hospitalization.Results:At screening, women were 62±7 years, 49% from underrepresented racial and ethnic populations, and 59% were at least high school graduates. At baseline women reported a mean of 2±.01 SLEs over the past year. Mean PSS scores were 4.16±3.09. Over a median of 15 years, there were 1,624 incident HF events (HFpEF, n=998; HFrEF, n=626). In fully adjusted models neither the number of SLEs or PSS scores were associated with HF risk(Table 1).Conclusions:In this WHI cohort, the number of SLEs and perceived stress were not prospectively associated with risk of HF, HFpEF, or HFrEF hospitalization. Future research is needed to understand whether specific types of stressors, stress measured more proximally to HF onset, or lab-based stress assessments may capture an association of stress with HF risk.

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Novembre 2024

Abstract 4134792: SIRTUIN5 Modulates Na+/Ca2+ Handling Via Oxidative Stress Dependent Manner In Mouse Heart

Circulation, Volume 150, Issue Suppl_1, Page A4134792-A4134792, November 12, 2024. Background:The cardiac Na+channel NaV1.5 (encoded bySCN5A) governs cardiac inward Na+current (INa) and the fast upstroke and plateau phases of the cardiac action potential. Mutations in NaV1.5 can cause acquired or inherited arrhythmias and conduction diseases, including ~20% of cases of Brugada Syndrome (BrS). Changes in INacan impact Ca2+handling and cardiac excitation-contraction coupling. We have previously shown that SIRT1-mediated deacetylation of NaV1.5 increased INa. Recently, potential mutations (including P114T) in SIRT5, another NAD+-dependent deACYLase in the Sirtuin family localized to mitochondria, were identified in small families with BrS.Hypothesis:Sirt5 dysfunction evokes arrhythmias via Na+and Ca2+mishandling in an oxidative stress-dependent manner in mouse hearts.Aims:To explore the potential role of SIRT5 in BrS using heterologous expression systems and homozygous P114T-Sirt5 knock-in (P114T-KI) mice.Methods:Protein expression and physical interactions were detected by immunoprecipitation and immunoblot. The effects of SIRT5 on Na+current was measured using patch clamp in HEK cells and mouse cardiac myocytes. Confocal microscopy was used to measure reactive oxygen species (ROS) and for Ca2+imaging.Results:Both WT and P114T-SIRT5 co-immunoprecipitate with NaV1.5, but WT increased peak INain HEK cells while P114T did not (Fig A,B). Live-cell staining using DCFDA or mitoSOX showed that P114T-KI hearts had increased basal ROS and were more sensitive to oxidative stress induced by H2O2than WT littermates. P114T-KI hearts had increased Na+/Ca2+exchange protein 1 (NCX1) expression, and Langendorff-perfused hearts displayed abnormal Ca2+handling and arrhythmias (Fig C). Notably, treatment with the mitochondrial ROS scavenger mitotempo mitigated the aberrant Ca2+handling and arrhythmias.Conclusion:These findings suggest that the P114T-SIRT5 causes abnormal Na+and Ca2+handling and arrhythmias in a ROS-dependent manner, highlighting potential mechanisms underlying BrS. This finding may pave the way for the use of SIRT5 or its activators as novel anti-arrhythmic therapies in the future.

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Novembre 2024

Abstract 4145104: Can Stress Echocardiography during Cardiopulmonary Exercise Testing Help Predict Clinical Outcomes in Right-Sided Congenital Heart Disease?

Circulation, Volume 150, Issue Suppl_1, Page A4145104-A4145104, November 12, 2024. Background:The optimal timing for intervention for pulmonary and right ventricular outflow tract stenosis in adult congenital heart disease (ACHD) remains uncertain. While stress echocardiography is an established modality to improve risk stratification in stenotic left-sided lesions, its utility in right-sided valve disease in the ACHD population has not been studied. We assessed if stress echocardiographic assessment of right ventricular (RV) function during cardiopulmonary exercise testing (CPET) can facilitate risk stratification in the ACHD population.Objectives:The purpose of this study was to determine the relationship between RV augmentation on stress echocardiogram during CPET and morbidity in ACHD patients with sub-pulmonary right ventricles and right-sided stenotic lesions.Methods:A retrospective cohort study of ACHD patients with sub-pulmonary right ventricles who underwent CPET with stress echocardiogram was performed. The primary outcome was defined as having at least one of the following: 1) cardiac related hospitalization, 2) new documented arrhythmia, or 3) new or worsening heart failure. RV augmentation on stress echo was verified by concordance with a second observer.Results:The study included 87 patients, 41 (47%) with repaired tetralogy of Fallot, 9 (10.3%) with RV-PA conduits, and 9 (10.3%) with pulmonary stenosis. On baseline transthoracic echocardiogram, median peak pulmonary valve gradient was 38.7 mmHg (Q1 17.9 , Q3 49.0) and 30% of patients had RV dysfunction. On stress imaging, 13 (14.9%) did not demonstrate RV augmentation. Those without RV augmentation had a lower percent predicted peak Vo2 (61.4% vs 75.4%, p=0.007). Eleven (12.6%) met the primary outcome. Lack of RV augmentation was strongly associated with the primary outcome (OR 4.25, CI 1.04 –17.46, p = 0.04). This association remained true in patients with baseline peak PV gradients less than 50mmHg (OR 8.7, CI 1.68 – 46.79, p = 0.009) and was more pronounced in patients with tetralogy of Fallot (OR 33.99, CI 3.29 – 829, p = 0.007).Conclusions:Lack of RV augmentation on stress echo during CPET is associated with increased morbidity in ACHD patients with right-sided stenotic lesions. These results suggest that stress echocardiography at the time of CPET should be considered in this population.

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Novembre 2024