Cardiac Output Research Articles

Assessing the Impact of Cardiac Output and Valve Orientation on Bioprosthetic Pulmonary Valve Hemodynamics Using In Vitro 4D-Flow MRI and High-Speed Imaging.

Pulmonary valve replacement (PVR) using bioprosthetic valves is a common procedure performed in patients with repaired Tetralogy of Fallot and other conditions, but these valves frequently become dysfunctional within 15years of implantation. The causes for early valve failure are not clearly understood. The purpose of this study was to explore the impact of changing cardiac output (CO) and valve orientation on local hemodynamics and valve performance. A 25mm bioprosthetic valve was implanted in an idealized 3D-printed model of the right ventricular outflow tract (RVOT). The local hemodynamics at three COs and two valve orientations were assessed using 4D-Flow MRI and high-speed camera imaging. Noticeable differences in jet asymmetry, the amount of recirculation, leaflet opening patterns, as well as the size and location of reversed flow regions were observed with varying CO. Rotation of the valve resulted in drastic differences in reversed flow regions, but not forward flow. Flow features observed in the valve with low CO in this study have previously been correlated with calcification, hemolysis, and leaflet fatigue, indicating their potential negative impact on local hemodynamics and leaflet performance.

Cardiac output-guided haemodynamic therapy for patients undergoing major gastrointestinal surgery: OPTIMISE II randomised clinical trial

ObjectivesTo evaluate the clinical effectiveness and safety of a perioperative algorithm for cardiac output-guided haemodynamic therapy in patients undergoing major gastrointestinal surgery.DesignMulticentre randomised controlled trial.SettingSurgical services of 55 hospitals worldwide.Participants2498...

Advancing 3D Engineered In Vitro Models for Heart Failure Research: Key Features and Considerations

Heart failure is characterized by intricate myocardial remodeling that impairs the heart’s pumping and/or relaxation capacity, ultimately reducing cardiac output. It represents a major public health burden, given its high prevalence and associated morbidity and mortality rates, which continue to challenge healthcare systems worldwide. Despite advancements in medical science, there are no treatments that address the disease at its core. The development of three-dimensional engineered in vitro models that closely mimic the (patho)physiology and drug responses of the myocardium has the potential to revolutionize our insights and uncover new therapeutic avenues. Key aspects of these models include the precise replication of the extracellular matrix structure, cell composition, micro-architecture, mechanical and electrical properties, and relevant physiological and pathological stimuli, such as fluid flow, mechanical load, electrical signal propagation, and biochemical cues. Additionally, to fully capture heart failure and its diversity in vivo, it is crucial to consider factors such as age, gender, interactions with other organ systems and external influences—thereby recapitulating unique patient and disease phenotypes. This review details these model features and their significance in heart failure research, with the aim of enhancing future platforms that will deepen our understanding of the disease and facilitate the development of novel, effective therapies.

Intra-abdominal pressure, renal resistive index, sublingual microcirculation and total body water for guidance of volume resuscitation to avoid acute kidney injury during shock therapy

Background/objectivesShock and accompanying acute kidney injury (AKI) as a frequent complication is a well-known cause of morbidity and mortality worldwide. The current standard parameters to guide fluid resuscitation therapy (i.e., cardiac output, heart rate, blood pressure, central venous pressure) to avoid AKI and renal replacement therapy remain imprecise, and fluid overload with consequent organ oedema and high intestinal pressures result in further complications. The VoluKid study investigated additional non-invasive fluid volume parameters including assessment of total body water (TBW), renal vascular resistance [renal resistive index (RRI)], intra-abdominal pressure (IAP) and microcirculatory blood flow (MBF) to predict AKI during the first 72 h of intensive care therapy.Methods, design and analysisThis mono-centre observational cohort study included patients with shock who presented to the intensive care unit (ICU). Routine volume resuscitation parameters (i.e., cardiac output, heart rate, blood pressure, central venous pressure) were used to guide fluid therapy. In addition, four parameters, including MBF using sublingual incident dark-field microscopy, IAP, RRI assessed by duplex-sonography, and TBW using bioimpedance analysis (BIA), were measured daily and evaluated for predicting the primary outcome of acute kidney injury (AKI) and need for renal replacement therapy within the first 72 h of admission. Baseline and post-ICU admission values of these parameters were compared between patients with and without AKI.ResultsA total of 45 patients were enrolled in this study. Of those 45 patients, 37 could be followed for the entire study period of 72 h and 14 patients developed AKI (31.1%). Twelve patients (26.7%) had pre-existing renal impairment, one of whom died during the observation period. Nineteen patients (42.2%) had no renal impairment. RRI and IAP did not differ between patients with AKI and without AKI and did not predict AKI. TBW measured by BIA predicted AKI (p = 0.029). After adjustment for covariates (age, body mass index,and gender) this prediction was not significant [adjusted odds rato (OR) 0.99, p = 0.258, 95% confidence interval (CI) [0.97,1.01]]. MBF could not be estimated due a high number of missing values.ConclusionsBased on our limited data, none of the non-invasive parameters (TBA, IAP, RRI,) serve as predictors for AKI when assessed during the first 72 h after ICU admission, either when analysed separately or in combination.RegistrationClinicalTrials.gov Identifier: NCT02666404, registered 28/01/2016; URL: https://classic.clinicaltrials.gov/ct2/show/NCT02666404.

Respiratory sinus arrhythmia in humans: Correlation analysis with breathing-specific heart rate

In adult humans at rest, pulmonary ventilation and cardiac output share similar values, both approximately 5 L/min. Airflow is intermittent, with tidal volumes exceeding dead space, low breathing frequency (fresp), and zero air velocity at both end-inspiration and end-expiration. In contrast, the cardiac pump is in series with the vasculature, such that the small stroke volume and high heart rate (HR) (fh) allow for quasi-continuous blood flow. Based on experimental findings in dogs, it has been suggested that an elevated fh during inspiration (known as respiratory sinus arrhythmia [RSA]) decreases the disparity between air and blood flow patterns. Thus, one might hypothesize a positive correlation between the peak-trough difference of instantaneous fh (ΔHR’ = HR’peak – HR’trough) and the breathing-specific fh (fh/fresp). To test this hypothesis, we combined breath-by-breath data for ΔHR’ from several previous studies, resulting in a database of over 600 subjects. This extensive dataset allowed us to construct statistically meaningful correlations between ΔHR’ and variables associated with RSA (fh, fresp, HR’peak, and HR’trough). A strong statistically significant (r > 0.9) correlation between fh/fresp and ΔHR’ was observed. These findings support the hypothesis that RSA may be a mechanism for improving the match between the quasi-continuous blood flow and the intermittent airflow.

CMR and adverse clinical outcomes in peripartum cardiomyopathy

BackgroundPeripartum cardiomyopathy (PPCM) is associated with significant morbidity and mortality. Recent studies show recovery of left ventricular ejection fraction (LVEF) can still be associated with longitudinal adverse clinical outcomes. Cardiac MRI (CMR) may yield additional prognostic parameters of serious adverse outcomes (SAE) beyond LVEF. MethodsIndividuals with PPCM and CMR within 3 months of diagnosis were analyzed from the Investigations in Pregnancy Associated Cardiomyopathy (IPAC) trial and our institution from 2010-present. Indexed left ventricular (LV) mass, ventricular volumes, cardiac output, global longitudinal strain (GLS), extracellular cellular volume (ECV) as well as epicardial fat volume (EFV) were analyzed. SAEs included left ventricular assist device (LVAD), heart transplant and death. CMR parameters were compared between SAE and no SAEs groups by non-parametric techniques. ResultsAmong 51 individuals with mean age of 31 years at diagnosis, 6/51 (12 %) experienced 11 adverse outcomes. EF at time of CMR (15.0 vs 37.3 %, p < 0.001), peak GLS (−4.1 % vs −10.0, p = 0.002) and ECV (43.6 vs 28.2, p = 0.02) differed significantly among groups. In univariate regression analysis, worse LVEF, lower peak GLS and higher mean ECV along with greater LVESVi were predictive of adverse outcomes. ConclusionPrior studies found baseline LVEF by echo is a predictor of serious adverse outcomes. CMR identified LVESVi, peak GLS and ECV as additional predictors of adverse outcomes. If confirmed in larger studies, diffuse myocardial fibrosis may represent a therapeutic target in PPCM.

The Role of NAD+ in Myocardial Ischemia-induced Heart Failure in Sprague-dawley Rats and Beagles.

Nicotinamide adenine dinucleotide (NAD+) participates in various processes that are dysregulated in cardiovascular diseases. Supplementation with NAD+ may be cardioprotective. However, whether the protective effect exerted by NAD+ in heart failure (HF) is more effective before acute myocardial infarction (MI) or after remains unclear. The left anterior descending arteries of male Sprague Dawley rats and beagles that developed HF following MI were ligated for 1 week, following which the animals were treated for 4 weeks with low, medium, and high doses of NAD+ and LCZ696. Cardiac function, hemodynamics, and biomarkers were evaluated during the treatment period. Heart weight, myocardial fibrosis, and MI rate were measured eventually. Compared with the HF groups, groups treated with LCZ696 and different doses of NAD+ showed increased ejection fractions, fractional shortening, cardiac output, and stroke volume and decreased end-systolic volume, end-systolic dimension, creatine kinase, and lactic dehydrogenase. LV blood pressure was lower in the HF group than in the control group, but this decrease was significantly greater in the medium and high NAD+ dose groups. The ratios of heart weight indexes, fibrotic areas, and MI rates in the CZ696 and medium and high NAD+ dose groups were lower than those in the HF group. Medium and highdose NAD+ showed superior positive effects on myocardial hypertrophy, cardiac function, and myocardial fibrosis and reduced the MI rate.

Resveratrol alleviates heart failure by activating foxo3a to counteract oxidative stress and apoptosis

Resveratrol has been extensively studied for its multifaceted health benefits. Nonetheless, the pharmacological mechanisms of resveratrol for heart failure remain elusive, especially the cardioprotective effects. To address this knowledge gap, we performed high-throughput drug screening using zebrafish and discovered that resveratrol significantly alleviated heart failure, including rescuing abnormalities in heart rate, blood flow, cardiac output, and nppb overexpression. Mechanically, calcium optical mapping revealed that resveratrol diminished the prolongation of calcium duration at 90 % repolarization (CaD90). Membrane potential assay demonstrated that resveratrol alleviated mitochondrial damage, subsequently relieved the excessive accumulation of reactive oxygen species (ROS). Tunel staining further showed that resveratrol inhibited cardiomyocyte apoptosis both in zebrafish and human AC16 cell. Given the close relationship between the Forkhead Box O (foxo) family and oxidative stress and apoptosis, we used qPCR and noted that resveratrol could regulate the heart failure-induced expressions of foxo1b and foxo3a to normal levels. Furthermore, we conducted in situ hybridization to confirm the effective down-regulation patterns of foxo3a after resveratrol treatment. To investigate whether resveratrol’s effects are mediated via foxo3a, we used gardenoside to inhibit foxo3a expression, noting that resveratrol’s cardioprotective effects were reduced with foxo3a inhibition. Overall, our study underscores the molecular mechanisms by which resveratrol confers cardioprotection and provides a reference for heart failure therapeutic approaches.

Effect of Ischemic Preconditioning on Endurance Running Performance in the Heat

Ischemic preconditioning (IPC) is a strategy that may enhances endurance performance in thermoneutral environments. Exercising in the heat increases thermoregulatory and cardiovascular strain, decreasing endurance performance. The current study aimed to determine whether IPC administration improves endurance performance in the heat. In a randomized crossover design, 12 healthy subjects (V̇O2max: 54.4 ± 8.1 mL·kg-1·min-1) underwent either IPC administration (220 mmHg) or a sham treatment (20 mmHg), then completed a moderate-intensity 6-min running (EX1) and a high-intensity time-to-exhaustion running test (EX2) in a hot environment (35 °C, 50 % RH). Cardiac function, oxygen consumption (V̇O2), and core body temperature (TCORE) were measured. During EX2, IPC administration increased the total running time in the heat compared to the sham treatment (IPC: 416.4 ± 61.9 vs. sham 389.3 ± 40.7 s, P = 0.027). IPC administration also increased stroke volume (IPC: 150.4 ± 17.5 vs. sham: 128.2 ± 11.6 ml, P = 0.008) and cardiac output (IPC: 27.4 ± 1.7 vs. sham: 25.1 ± 2.2 ml min-1, P = 0.007) during 100% isotime of EX2. End-exercise V̇O2 (IPC: 3.72 ± 0.85 vs. sham: 3.54 ± 0.87 L·min-1, P = 0.017) and slow phase amplitude (IPC: 0.57 ± 0.17 vs. sham: 0.72 ± 0.22 L·min-1, P = 0.016) were improved. When compared with the baseline period, an increase in TCORE was less in the IPC condition during EX1 (IPC: 0.18 ± 0.06 vs. sham: 0.22 ± 0.08 °C, P = 0.005) and EX2 (IPC: 0.87 ± 0.10 vs. sham: 1.03 ± 0.10 °C, P &lt; 0.001). IPC improves high-intensity endurance performance in the heat by 6.9 %. This performance benefit could be associated with improved cardiac and thermoregulatory function engendered by IPC administration.

Current Landscape of Compression Products for Treatment of Postural Orthostatic Tachycardia Syndrome and Neurogenic Orthostatic Hypotension

Background/Objectives: Patients with postural orthostatic tachycardia syndrome (POTS) or neurogenic orthostatic hypotension (nOH) experience vertigo, confusion, and syncope. Compression garments help reduce venous pooling in these patients, thereby increasing cardiac output. We aimed to determine end-user opinions of compression products intended to alleviate symptoms for POTS and nOH. Methods: This was a survey study sampling participants diagnosed with POTS or nOH. The data collected included demographics, medical history, and compression garments previously used. The participants rated their most frequently used garment across comfort, aesthetic appeal, ease of use, durability, cost-effectiveness, efficacy, and consistency on the Likert scale (1–5). One-way ANOVA was used to compare the design criteria ratings across garments. For all tests α = 0.05. Results: Of the 330 POTS and 28 nOH participants surveyed (mean age 37.9, mean BMI 27.5, 95.0% women, 90.5% White), 354 (98.9%) reported trying at least one compression garment since their diagnosis. The majority of participants reported using leg compression most frequently rather than shapewear or abdominal compression (65.4% vs. 20.1% vs. 13.4%, respectively). Approximately 67.0% of participants tried multiple product types. Shapewear was reported to have greater concealability compared to abdominal or leg compression garments (mean 3.43 vs. 2.90 vs. 2.91, respectively; p &lt; 0.01). Shapewear and abdominal compression were rated to be less comfortable compared to leg compression (2.67 vs. 2.94 vs. 3.05, respectively; p = 0.03). Conclusions: The existing compression products do not fully meet needs of individuals with POTS or nOH, as evidenced by participant ratings on multiple domains. There is potential consumer demand for novel adjustable abdominal compression garments that are low-profile and comfortable when disengaged.

Genotypic Influences on Actuators of Aerobic Performance in Tactical Athletes

Background: This study examines genetic variations in the systemic oxygen transport cascade during exhaustive exercise in physically trained tactical athletes. Research goal: To update the information on the distribution of influence of eleven polymorphisms in ten genes, namely ACE (rs1799752), AGT (rs699), MCT1 (rs1049434), HIF1A (rs11549465), COMT (rs4680), CKM (rs8111989), TNC (rs2104772), PTK2 (rs7460 and rs7843014), ACTN3 (rs1815739), and MSTN (rs1805086)—on the connected steps of oxygen transport during aerobic muscle work. Methods: 251 young, healthy tactical athletes (including 12 females) with a systematic physical training history underwent exercise tests, including standardized endurance running with a 12.6 kg vest. Key endurance performance metrics were assessed using ergospirometry, blood sampling, and near-infrared spectroscopy of knee and ankle extensor muscles. The influence of gene polymorphisms on the above performance metrics was analyzed using Bayesian analysis of variance. Results: Subjects exhibited good aerobic fitness (maximal oxygen uptake (VO2max): 4.3 ± 0.6 L min−1, peak aerobic power: 3.6 W ± 0.7 W kg−1). Energy supply-related gene polymorphisms rs1799752, rs4680, rs1049434, rs7843014, rs11549465, and rs8111989 did not follow the Hardy–Weinberg equilibrium. Polymorphisms in genes that regulate metabolic and contractile features were strongly associated with variability in oxygen transport and metabolism, such as body mass-related VO2 (rs7843014, rs2104772), cardiac output (rs7460), total muscle hemoglobin content (rs7460, rs4680), oxygen saturation in exercised muscle (rs1049434), and respiration exchange ratio (rs7843014, rs11549465) at first or secondary ventilatory thresholds or VO2max. Moderate influences were found for mass-related power output. Conclusions: The posterior distribution of effects from genetic modulators of aerobic metabolism and muscle contractility mostly confirmed prior opinions in the direction of association. The observed genetic effects of rs4680 and rs1049434 indicate a crucial role of dopamine- and lactate-modulated muscle perfusion and oxygen metabolism during running, suggesting self-selection in Swiss tactical athletes.

Volume assessment comparing femoral vein and inferior vena cava among chest pain patients presenting to the emergency department

BackgroundInferior vena cava (IVC) diameter measurement using ultrasound for volume status assessment has shown satisfactory results and is being adopted in Emergency and critical care settings. IVC diameter can vary depending on the cardiac function, respiratory efforts, intraabdominal pressure, and mechanical ventilation. Due to these factors, IVC measurement cannot be considered a stand-alone technique appropriate for every patient. The femoral vein (FV), a more superficial vein than IVC, can be considered an alternative method for assessing fluid responsiveness in patients presenting to the Emergency department. It is easily accessible and can be used in scenarios where IVC cannot be visualized or reliable.MethodsThis was a single-center diagnostic study where 85 patients who presented to the ED with chest pain were enrolled prospectively. IVC and femoral vein collapsibility indices, stroke volume, and cardiac output are measured using an ultrasound machine. The measurements were repeated after a passive leg-raising test. These values were compared with each other to assess an intra-class correlation between IVC and femoral vein collapsibility indices. We have also evaluated the relationship between the collapsibility indices of both veins and cardiac output.Discussion & limitationsOur findings show an insufficient correlation between IVC and FV collapsibility indices. However, both vein diameters significantly increased after passive leg raising (PLR), indicating a response to fluid challenge. Post-PLR reduced IVC, and FV collapsibility index (CI) suggests intravascular volume expansion after a fluid challenge, also reflected in the hemodynamic parameters. Our study was conducted only in a subset of relatively stable patients. The applicability of the study in different subsets of patients presenting to ED is still questionable.ConclusionWe conclude that femoral vein indices may not be an accurate alternative for volume assessment in the chosen cohort of patients. IVC and FV metrics do not correlate and may not be accurate for volume responsiveness. We may need to explore the utility of FV and its indices in a larger population in multiple settings for a better understanding of its role in volume assessment and responsiveness.Trial registration(EC/NEW/INST/2021/1707). Registered 03 January 2023.

Evaluation of Cardiologic Alterations in Radiographs of Dogs with Bronchopneumonia Before and After Treatment

Pneumonia, a common respiratory disease in small animals, causes significant hypoxemia in dogs due to reduced lung capacity and cardiac output. In addition, pneumonia may lead to cardiac complications. This study aimed to evaluate the alterations in cardiac silhouette and main vessel views in dogs that underwent bronchopneumonia treatment, and the alterations were evaluated in radiographs of the dogs with bronchopneumonia before and after treatment. For this purpose, radiographic data from 26 dogs diagnosed with and treated for bronchopneumonia were analyzed. The measurements included left atrial size, long axis, short axis, the fourth thoracic vertebra length, aorta width, caudal vena cava width, and thoracic width. Radiographs obtained before and after treatment indicated no changes in the long and short axes of the vertebral hearth score, the fourth thoracic vertebrae length, aorta and caudal vena cava width, and thoracic width. However, in pre-treatment radiographs, the left atrial size was found to be larger compared to post-treatment radiographs. A strong positive correlation was observed between measurements of LAs and LAs/TV4 in both pre- and post-treatment radiographs, as well as in the measurement differences between pre- and post-treatment radiographs. As a consequence, the radiographs employed to monitor bronchopneumonia treatment may serve as an initial indicator of potential cardiac complications in affected dogs.

Prognostic relevance of Exercise Pulmonary Hypertension: Results of the multi-center PEX-NET Clinical Research Collaboration.

Exercise pulmonary hypertension (exercise PH) was defined by a mean pulmonary arterial pressure (mPAP)/cardiac output (CO) slope >3 mmHg·L-1·min-1 between rest and exercise in the 2022 ESC/ERS PH guidelines. However, large, multi-center studies on the prognostic relevance of exercise hemodynamics and its added value to resting hemodynamics are missing. The PEX-NET (Pulmonary Hemodynamics during Exercise Network) registry enrolled patients who underwent clinically indicated right heart catheterizations both at rest and ergometer exercise from 23 PH-centers worldwide. In this retrospective analysis we included subjects with resting mPAP<25 mmHg and complete hemodynamic data at rest and exercise in the same body position. Mixed effects Cox proportional hazard models with random effect center were applied to identify independent markers of prognosis among the hemodynamic parameters. We included n=764 patients (64% females, age: 59yrs (IQR:46-69), mPAP: 17 mmHg (IQR:14-20)). Median observation time was 6.8yrs (range:0.1-15.9) and 87 patients (11%) died during follow-up. After adjustment for age, sex, hemoglobin level, and resting hemodynamics, CO (p=0.001; HR: 0.85 (95%CI:0.77-0.93)) and trans-pulmonary gradient (p=0.044; HR: 1.04 (95%CI:1.00-1.08)) at peak exercise and the mPAP/CO slope (p<0.001; HR: 1.12 (95%CI:1.06-1.18)) were the only independent predictors of prognosis. Patients with mPAP/CO slope >3 mmHg·L-1·min-1 had significantly worse survival compared to those with ≤3 mmHg·L-1·min-1 (p=0.013; HR: 2.04 (95%CI:1.16-3.58)). The mPAP/CO slope is a robust and independent predictor of prognosis in patients with normal or mildly elevated resting pulmonary arterial pressure that provides prognostic information beyond resting hemodynamics and appears suitable to define exercise PH.

Machine Learning-Based Cardiac Output Estimation Using Photoplethysmography in Off-Pump Coronary Artery Bypass Surgery

Background/Objectives: Hemodynamic monitoring is crucial for managing critically ill patients and those undergoing major surgeries. Cardiac output (CO) is an essential marker for diagnosing hemodynamic deterioration and guiding interventions. The gold standard thermodilution method for measuring CO is invasive, prompting a search for non-invasive alternatives. This pilot study aimed to develop a non-invasive algorithm for classifying the cardiac index (CI) into low and non-low categories using finger photoplethysmography (PPG) and a machine learning model. Methods: PPG and continuous thermodilution CO data were collected from patients undergoing off-pump coronary artery bypass graft surgery. The dataset underwent preprocessing, and features were extracted and selected using the Relief algorithm. A CatBoost machine learning model was trained and evaluated using a validation and testing phase approach. Results: The developed model achieved an accuracy of 89.42% in the validation phase and 87.57% in the testing phase. Performance was balanced across low and non-low CO categories, demonstrating robust classification capabilities. Conclusions: This study demonstrates the potential of machine learning and non-invasive PPG for accurate CO classification. The proposed method could enhance patient safety and comfort in critical care and surgical settings by providing a non-invasive alternative to traditional invasive CO monitoring techniques. Further research is needed to validate these findings in larger, diverse patient populations and clinical scenarios.

The blood flow and vascular responses in dynamically exercising skeletal muscles evoked by combination of cold stimulation and voluntary apnea in humans.

We evaluated (1) the combined effects of cold stimulation and voluntary breath holding (apnea) on heart rate, blood pressure, blood flow and vascular responses in dynamically exercising muscles in humans, and (2) if some interactions exist between cold stimulation and apnea on the cardiovascular responses. Nine males and 1 female performed three trials entailing a dynamic two-legged knee extension exercise at a constant workload that elicited heart rates around 100 beats min-1. During the trials the participants performed either: (1) immersed their right hand into ice water maintained at 4°C (cold pressor test; CPT); (2) performed maximal-duration apnea; and (3) performed a combination of CPT and apnea. Leg blood flow (LBF) and cardiac output (CO) were measured simultaneously using two Doppler ultrasound systems. CPT induced a rise in mean arterial pressure (MAP) (P < 0.05) but had no significant effect on CO or exercising leg vascular conductance (LVC). Apnea evoked large pressor responses, bradycardia and decreases in CO, LBF and LVC (all P < 0.05). The increase in MAP induced by combined CPT and apnea was smaller than the sum of those induced separately by CPT or apnea (P < 0.05). Combined CPT and apnea decreased LBF and LVC to a similar extent as apnea alone. Addition of local cold stimulation to apnea does not enhance pressor responses or vasoconstriction within active muscles. This suggests that maximum voluntary apnea evokes massive vasoconstriction, even within exercising muscles, which cannot be enhanced by additional sympathetic stimulation.

MoS2 Nanosheets at Low Doses Induced Cardiotoxicity in Developing Zebrafish via Ferroptosis: Influence of Lateral Size and Surface Modification.

The widespread applications of molybdenum disulfide (MoS2) nanosheets inevitably result in their release into aquatic environments, necessitating an exploration of their potential toxic effects on aquatic organisms. This study analyzes the cardiac responses of zebrafish larvae exposed to MoS2, with a focus on the influence of size and surface modifications. At higher concentrations (1 and 5 mg/L), MoS2 nanosheets hampered larval growth without influencing cardiomyogenesis. At lower doses (0.5-100 μg/L), small-sized MoS2 (ssMoS2, 187.2 nm) significantly impaired cardiac development, as proved by morphology abnormality, decreased heartbeat, stroke volume, and cardiac output, whereas these undesirable changes were not observed in the cysteine-modified form. Large-sized nanosheets (1.638 μm) did not localize to the heart, barely showing a cardiac disorder. Transcriptomics, biochemical analysis, and computational simulation validated that ssMoS2 aggravated Fe2+ overload through excessive ferritinophagy and ferroportin-1 inhibition, accompanied by down-regulation of glutathione peroxidase 4 and activation of PUFAs esterification, leading to ferroptosis. Significant associations between ferroptosis signals and cardiac indices, along with the ferrostatin-1 inhibition test, confirmed the ferroptosis-mediated cardiotoxicity of ssMoS2. Our study provides a key understanding of molecular events underlying MoS2-induced cardiotoxicity and highlights the importance of size and surface characteristics, which are significant for risk assessment and the safe design of nanoproducts.

Inotropes for the prevention of low cardiac output syndrome and mortality for paediatric patients undergoing surgery for congenital heart disease: a network meta-analysis.

Inotropes for the prevention of low cardiac output syndrome and mortality for paediatric patients undergoing surgery for congenital heart disease: a network meta-analysis.

SGLT2 inhibitors in the prevention of diabetic cardiomyopathy: Targeting the silent threat.

Heart failure (HF) is a major global health challenge, particularly among individuals with type 2 diabetes mellitus (T2DM), who are at significantly higher risk of developing HF. Diabetic cardiomyopathy, a unique form of heart disease, often progresses silently until advanced stages. Recent research has focused on sodium-dependent glucose transporter 2 inhibitors (SGLT2i), originally developed for hyperglycemia, which have shown potential in reducing cardiovascular risks, including HF hospitalizations, irrespective of diabetic status. In this editorial we comment on the article by Grubić Rotkvić et al published in the recent issue of the World Journal of Cardiology. The investigators examined the effects of SGLT2i on myocardial function in T2DM patients with asymptomatic HF, finding significant improvements in stroke volume index and reductions in systemic vascular resistance, suggesting enhanced cardiac output. Additionally, SGLT2i demonstrated anti-inflammatory and antioxidant effects, as well as blood pressure reduction, though the study's limitations-such as small sample size and observational design-necessitate larger randomized trials to confirm these findings. The study underscores the potential of early intervention with SGLT2i in preventing HF progression in T2DM patients.

Transcatheter Interventions in Adults With Fontan Palliation.

The Fontan circuit is associated with chronically elevated systemic venous pressures and decreased cardiac output, often leading to circuit failure. Managing Fontan circuit failure is complex and requires multiple therapeutic options. Transcatheter interventions have emerged as a reliable approach. They can alleviate obstructions and improve cyanosis by enhancing pulmonary blood flow and oxygen saturation. These procedures can also increase cardiac output and reduce systemic venous pressure, contributing to patient stabilization. In addition, they help mitigate volume overload and decrease the risk of bleeding during heart or combined heart and liver transplants. In recent years, percutaneous interventions have rapidly evolved and become a key therapeutic option for addressing various aspects of Fontan circuit failure. These interventions should be considered integral to the management strategy for this specific patient population.