Pressure-volume Area Research Articles

Left ventricular venting during extracorporeal membrane oxygenation; the effects on cardiac performance in a porcine model of critical post-cardiotomy failure.

Left ventricular distension is a major concern with postcardiotomy veno-arterial extracorporeal membrane oxygenation (VA-ECMO) supporting a critical heart failure after cardiac surgery. This porcine study evaluates the effects of left ventricular venting on cardiac function during ECMO-supported circulation and after weaning from ECMO. Twenty anaesthetised open-chest pigs were put on cardiopulmonary bypass with aortic cross-clamping and suboptimal cardioplegic arrest for 40min. After declamping and defibrillation, the animals were supported by VA-ECMO for 180min either with or without additional left ventricular venting. Continuous haemodynamic evaluations were performed at baseline and at cardiac arrest, during VA-ECMO and for 120min after weaning from circulatory support. Left ventricular perfusion and function were evaluated with microspheres, pressure-volume loops and epicardial echocardiography at baseline and after 1 and 2h with unsupported circulation. In vented animals both mean aortic and left ventricular peak systolic pressure increased at the end of the ECMO-supported period compared to those not vented and remained increased also after weaning. Both at 60 min and 120min after weaning from circulatory support, left ventricular stroke work and pressure-volume area were increased in vented compared to not vented animals. At 120min left ventricular stroke volume was increased in vented compared to not vented animals, myocardial perfusion did not differ. The left ventricular mechanical efficiency, defined as the ratio between pressure volume area and myocardial perfusion, was increased (53.2 ± 5 vs 36.2 ± 2.1J/mL/g, p = 0.011) in vented- compared to not vented hearts. This experimental study demonstrate that left ventricular venting during post-cardiotomy veno-arterial ECMO for 3h attenuates deterioration of left ventricular function and haemodynamics early after weaning from circulatory support.

The Left Ventricular Pressure-Volume Area and Stroke Work in Porcine Model of Ascending Compared to Descending Thoracic Aorta Stenosis Creating a Chronic Early Vs. Late Left Ventricular Afterload Increase.

Objective: Left ventricular hypertrophy in aortic stenosis, arterial hypertension or coarctation of the aorta is risk factor for early development of HF. In chronic late compared to early left ventricular afterload increases resulting from descending thoracic оr ascending aorta stenosis, we assess the left ventricular stroke work, pressure-volume area for О2 demand and effective work on the 4th and 8th weeks. It is suggested that reduced proximal thoracic aortic compliance presents with myocardial ischemia. However, development of adverse left ventricular hypertrophic remodeling and HF in different peak of LV afterload increase is understood poorly. Methods: Fourteen domestic male pigs (28 ± 3 kg) underwent descending thoracic or ascending aortic stenosis through posterior lateral thoracotomy, with cMRI and an invasive left ventricular pressure-volume loops' аrea assessment (Millar 5Fr pig-tailed conductance catheter) on the 4th and 8th weeks. Left ventricular stroke work and pressure-volume area PVA, parameter for LV O2 demand, were assessed in hypertrophic left ventricular remodeling, resulting from different peaks in LV afterload (late vs. early LV afterload) increase and we thus defined early adverse LV hypertrophic remodeling in linear and nonlinear end-systolic pressure-volume regression analysis. For this we used special software. Data was compared with two-way repeated measures ANOVA. Results presented are means ± (SEM) or medians and significance is set at p < 0.05. Results: The left ventricular nonlinear PVA was not different, in LL compared to EL on the 8th week and when using the linear regression analysis. Stroke work was not different. The linear and nonlinear potential energy were not different between LL vs. the EL group. Nonlinear bLVO2 demand was not different, being higher in LL compared to EL in the 8th week. Indexed PVA parameters were not different or changed between the 4th and 8th weeks, when being normalized for body surface-area (m²) or 100 grams of LV mass. Conclusion: The left ventricular potential energy, PVA with effective work and LVO2 demands are not different in hypertrophic LV remodeling in LL vs. EL group at the 8th week. Difference is not present when end-systolic pressure-volume relation is assessed from indexed LV volumes for m² BSA or 100 grams of LV mass. EL is as important as LL in increased LV afterloads based on LV work and mechanical coupling in this hypertensive heart failure model having preserved EF.

Effects of oxymatrine and matrine on left ventricular contractility using pressure-volume relationship analysis in anesthetized rats

The purpose of this study was to investigate the effects of oxymatrine and matrine on integrated cardiac function in rats using pressure-volume loop analysis. A pressure-volume loop catheter was advanced into the left ventricle in anesthetized rats. Steady-state hemodynamic and load-independent parameters were recorded before and after oxymatrine or matrine injection. Oxymatrine (200 mg/kg) and matrine (50, 100 mg/kg) significantly increased the preload recruitable stroke work, slope of maximal systolic pressure increase (dP/dtmax) – end-diastolic volume relationship, end-systolic elastance and volume axis intercept (V0), which are load-independent parameters. Furthermore, the observed increased cardiac efficiency, along with the decreased ventricular arterial coupling, pressure volume area and potential energy, reflect improved mechanoenergetics in oxymatrine (200 mg/kg) and matrine (25, 50 or 100 mg/kg) treated rats respectively. In addition, matrine (25, 50 mg/kg) decreased end-systolic volume and end-diastolic volume, and increased ejection fraction; matrine at 100 mg/kg further decreased end-systolic volume, end-diastolic volume, stroke volume and stroke work, shortened the time constant of left ventricular pressure decay, and increased dP/dtmax, and heart rate. These results suggest that both oxymatrine and matrine enhance left ventricular contractility and improve cardiac mechanical function. As the dose of matrine was much lower than that of oxymatrine, the effect of matrine on myocardial contractility was stronger than that of oxymatrine.

Ventricular and Atrial Pressure-Volume Loops: Analysis of the Effects Induced by Right Centrifugal Pump Assistance.

The main indications for right ventricular assist device (RVAD) support are right heart failure after implantation of a left ventricular assist device (LVAD) or early graft failure following heart transplantation. We sought to study the effects induced by different RVAD connections when right ventricular elastance (EesRIGHT) was modified using numerical simulations based on atrial and ventricular pressure–volume analysis. We considered the effects induced by continuous-flow RVAD support on left/right ventricular/atrial loops when EesRIGHT changed from 0.3 to 0.8 mmHg/mL during in-series or parallel pump connection. Pump rotational speed was also addressed. Parallel RVAD support at 4000 rpm with EesRIGHT = 0.3 mmHg/mL generated percentage changes up to 60% for left ventricular pressure–volume area and external work; up to 20% for left ventricular ESV and up to 25% for left ventricular EDV; up to 50% change in left atrial pressure-volume area (PVLAL-A) and only a 3% change in right atrial pressure–volume area (PVLAR-A). Percentage variation was lower when EesRIGHT = 0.8 mmHg/mL. Early recognition of right ventricular failure followed by aggressive treatment is desirable, so as to achieve a more favourable outcome. RVAD support remains an option for advanced right ventricular failure, although the onset of major adverse events may preclude its use.

Hemodynamic Response and Periprocedural Right Ventricular Function During a Lateral Thoracotomy versus Median Sternotomy Surgical Approach to Implantation of a Left Ventricular Assist Device - A Pilot Study

<h3>Purpose</h3> While continuous-flow LVADs improve survival in patients with advanced heart failure, right ventricular dysfunction continues to be a significant clinical challenge. Lateral thoracotomy implantation of LVADs has been postulated to reduce right ventricular failure, and the need for RVAD support, but recently published reports are conflicting. However, data regarding the impact of implantation technique on perioperative right ventricular hemodynamics are lacking. <h3>Methods</h3> Twenty-one patients were randomized to receive LVAD implantation via median sternotomy (MS) or lateral thoracotomy (LT). All implants were performed on cardiopulmonary bypass (CPB), and patients were weaned from CPB per institutional practice. In addition to standard perioperative hemodynamic monitoring, we placed a conductance catheter into the right ventricle to monitor the pressure-volume relationship in the perioperative period. <h3>Results</h3> Mean pulmonary artery pressures declined for both patient groups, while right atrial pressure increased from baseline to post-operative day 1 (POD1) in the MS group but decreased in the LT group. Among MS patients, metrics of contractility (stroke work and pressure volume area) decreased in the immediate perioperative period but returned to baseline by POD1. In the LT group, metrics of contractility were similar or increased from baseline on POD1. <h3>Conclusion</h3> In this pilot analysis, thoracotomy implantation of LVADs was associated with improved right ventricular function in the perioperative period. The more favorable hemodynamics in the LT group provide insight into the physiological mechanism by which right ventricular dysfunction is reduced in other clinical reports.

Combining VA-ECMO and Impella (EC-Pella) Before Reperfusion Mitigates Left Ventricular Injury Due to VA-ECMO in Acute Myocardial Infarction

<h3>Purpose</h3> Combining veno-arterial extracorporeal membrane oxygenation (ECMO) with an Impella CP (EC-Pella) is increasingly used in acute myocardial infarction (AMI). We recently reported that compared to reperfusion alone, ECMO increases, but Impella decreases infarct size in preclinical models. Whether EC-Pella limits cardiac damage remains unknown. We hypothesized that compared to ECMO alone, EC-Pella mitigates left ventricular (LV) injury when activated before reperfusion in AMI. <h3>Methods</h3> Ischemia-reperfusion injury (IRI) was induced in adult swine via percutaneous occlusion of the left anterior descending artery (LAD) for 120 minutes. We then activated either ECMO alone for 30 minutes or EC-Pella for 45 minutes with persistent LAD occlusion. All groups underwent 180 minutes of reperfusion (n=4-6/group). To study whether the sequence of device activation impacts infarct size, we compared activation of ECMO alone for 30 minutes followed by simultaneous Impella CP for 15 minutes (EC-Pella A) versus Impella CP activation for 30 minutes followed by simultaneous ECMO for 15 minutes (EC-Pella B) before reperfusion. LV hemodynamics, infarct size relative to the area at risk (IS) and cardioprotective signaling were assessed. <h3>Results</h3> Compared to IRI, ECMO increased IS. Compared to ECMO, IS was reduced in both EC-Pella groups (Fig. 1A). No difference in IS was observed between EC-Pella A versus EC-Pella B. Pressure-volume area (PVA) was lowest in EC-Pella B (Fig. 1B). Compared to IRI and ECMO, both EC-Pella configurations increased levels of phosphorylated Akt, Erk, and GSK3b within the infarct zone (Fig. 1C) and reduced pro-apoptotic signaling. <h3>Conclusion</h3> We report for the first time that compared to ECMO alone, initiation of EC-Pella before reperfusion reduces LV PVA, activates cardioprotective signaling, and reduces infarct size. These findings suggest that LV unloading may mitigate LV injury due to ECMO when applied before reperfusion in AMI.

Maximization of the output power of low concentrating photovoltaic systems by the application of reflecting mirrors

Solar energy is among the most commonly used sources of renewable energy since sun is available for a significant portion of the year in most parts of the world. Energy from sun can be harnessed through several technologies with continuous progress and development. Concentrated solar power systems apply mirrors or lenses as well as solar tracking systems for the concentration of a large solar radiation area into a tiny PV area. Due to high price of solar panels, several efficiency enhancement methods are being evaluated by researchers throughout the world. In this research, a form of solar technology, i.e. photovoltaic system, was applied to present developed low concentrator photovoltaic system (LCPVS) with cooling. This project aimed to determine how solar panel power output was changed by the application of mirrors to concentrate solar radiation; which they had concentration onto panel for increasing power output from 1 to 4 mirrors with the cooling system. In fact, the aim was to increase the output power by enhancing the amount of solar radiation which reaches the same surface area of solar panel via mirrors. Furthermore, application of mirrors saves PV area which is more economical. Also, the results were compared to a reference solar panel for determining how to increase the power output of a single panel (normal panel receiving solar radiation directly). The results showed that the value of the DC current (A) output of the four mirrors reflecting on the panel is three times greater than that of the reference panel, and the DC power (W) is almost three times greater than the reference panel's power.

Ventriculo-Arterial Coupling Is Associated With Oxygen Consumption and Tissue Perfusion in Acute Circulatory Failure.

IntroductionThe determination of ventriculo-arterial coupling is gaining an increasing role in cardiovascular and sport medicine. However, its relevance in critically ill patients is still under investigation. In this study we measured the association between ventriculo-arterial coupling and oxygen consumption (VO2) response after hemodynamic interventions in cardiac surgery patients with acute circulatory instability.Material and MethodsSixty-one cardio-thoracic ICU patients (67 ± 12 years, 80% men) who received hemodynamic therapeutic interventions (fluid challenge or norepinephrine infusion) were included. Arterial pressure, cardiac output, heart rate, arterial (EA), and ventricular elastances (EV), total indexed peripheral resistances were assessed before and after hemodynamic interventions. VO2 responsiveness was defined as VO2 increase >15% following the hemodynamic intervention. Ventriculo-arterial coupling was assessed measuring the EA/EV ratio by echocardiography. The left ventricle stroke work to pressure volume area ratio (SW/PVA) was also calculated.ResultsIn the overall cohort, 24 patients (39%) were VO2 responders, and 48 patients had high ventriculo-arterial (EA/EV) coupling ratio with a median value of 1.9 (1.6–2.4). Most of those patients were classified as VO2 responders (28 of 31 patients, p = 0.031). Changes in VO2 were correlated with those of indexed total peripheral resistances, EA, EA/EV and cardiac output. EA/EV ratio predicted VO2 increase with an AUC of 0.76 [95% CI: 0.62–0.87]; p = 0.001. In principal component analyses, EA/EV and SW/PVA ratios were independently associated (p < 0.05) with VO2 response following interventions.ConclusionsVO2 responders were characterized by baseline high ventriculo-arterial coupling ratio due to high EA and low EV. Baseline EA/EV and SW/PVA ratios were associated with VO2 changes independently of the hemodynamic intervention used. These results underline the pathophysiological significance of measuring ventriculo-arterial coupling in patients with hemodynamic instability, as a potential therapeutic target.

System cost minimisation in hybrid energy storage systems connected to microgrids: A comparative approach

Electricity is the most critical facility for humans. All traditional energy supplies are rapidly depleting. As a result, the energy resources are moved from traditional to non-conventional. In this research, mixture of two energy tools, namely wind and solar energy are used. Using a Hybrid Energy Storage System (HESS), continuous power can be provided. Electricity can be produced at a cost that is affordable. The integration of solar and wind in a hybrid system cause an increase in the system’s stability, which is the key benefit of this research. The system’s power transmission efficiency and reliability can be greatly enhanced by integrating these two intermittent sources. When one of the energy source is unavailable or inadequate to meet load demands, the other energy source will supply the power. The major contribution in this research is that, the proposed bidirectional single-inductor multiple-port (BSIMP) converter significantly lowers the component count, smaller circuit size and lower cost, allowing HESS to be integrated into DC microgrid. Minimum number of components are used for the same number of ESs in HESS in the proposed BSIMP converter. The hybridization of battery and supercapacitor (SC) for storage purpose is more cost effective, as compared to the battery energy storage system, thus improving the battery stress and hence used for large scale grid energy storage. SC’s are accepted as backup and found very useful in delivering high power, not possible with batteries. The use of SC in addition to batteries can be one solution for achieving the low life cycle economy. The Single Objective Adaptive Firefly Algorithm (SOAFA) is introduced for optimising the Proportional-Integral (PI) controller parameters. The system cost is reduced by about 32%, with the constraints on wind turbine swept area, PV area, total battery and SC capacity with the proposed optimisation algorithm.

Evaluation of High-Speed Link Parameters for Highly Reliable Reconfigurable Systems Based on S-Parameters and BER

Purpose of research. is to improve signal transmission parameters in high-speed signal transmission lines, including between programmable logic integrated circuits (PLIC). This improvement in signal transmission parameters is necessary to increase throughput of modern highly reliable reconfigurable systems to ensure data transfer rate of up to tens of Gbit/s. It can be done considering the influence of electrical and structural parameters of multi-layer printed circuit boards (MPCB) on them. It is possible to provide such high data rates by using a wider frequency band of transmitted signals. One of the existing approaches to this problem is to increase "physical" frequency of transmitted information signals to 25-300 GHz, which is sufficient to achieve desired rates.Methods. A method for estimating quality of high-speed signal transmission lines based on the definition of standardized methods for analyzing signal transmission parameters, such as JCOM, S-parameters and BER is proposed in the article. This method allows evaluating high-speed communication lines. Thus, the Channel Operating Margin (COM)/JCOM parameter can be used to estimate the quality of a digital communication channel - a standardized method for determining the overall channel quality indicator. Known methods are used to estimate such signal transmission parameters as S11 reflection coefficient and S21 attenuation coefficient (S-Parameters). These methods are used to estimate attenuation and loss of the information signal in the path, when copies of the signal reflected from inhomogeneities affect the original and lead to its distortion. Simulation of such parameter as Bit Error Rate (BER) is carried out according to G.821/G.826/M2100 rationing and quality control methodology.Results. The main metrics were selected to evaluate the quality of high-speed signal transmission lines. It is based on the evaluation of such signal transmission parameters as Channel Operating Margin (COM), S-parameters and Bit Error Rate (BER). Numerical evaluations of signal transmission parameters were obtained and their effect on the design parameters of high-speed signal transmission lines was estimated. It is recommended to use at least 1 transition hole between screening polygons in GND separation layers every 0.5 cm or 0.25 cm2 of WFP area. It is for a data rate of less than 25 Gbit/s, It is recommended to use at least 2 transition holes between screening polygons in GND separation layers every 0.5 cm or 0.25 cm² of PV area, if high-speed signal transmission line passes at a distance of closer than 2.5 cm from the power supply circuits in a projection on the layer where the power supply circuits are located.Conclusion. A method for calculating signal transmission parameters on high-speed signaling lines based on the calculation of Channel Operating Margin (COM), S-parameters and Bit Error Rate (BER) parameters is introduced. As part of introduced method, an analysis of signal transmission parameters was carried out. This analysis shows that when the "reference" values of electrical parameters of the line are met, the transfer holes contribute most to the signal distortion; then the layers in which the signal line is located, the number of screening polygons between the signal layers and the layers; in which the power supply circuits, the design parameters of the transition holes, as well as the length and number of segments of the high-speed line pass. Numerical evaluations of minimum number of transition holes and their diameter, the length of segments of differential pairs are given. These results can be used in pre-layout analysis step of high-speed signal transmission lines for computational modules of highly reliable reconfigurable systems.

Racial Differences in Val122Ile-Associated Transthyretin Cardiac Amyloidosis

The valine-to-isoleucine substitution (Val122Ile) is the most common variant of transthyretin (TTR) amyloidosis in the United States, affecting primarily individuals of African descent. This variant has been identified recently in a cluster of white individuals in Italy. Clinical phenotype and chamber performance of Black and white individuals with Val122Ile TTR cardiac amyloidosis (ATTR-CA) were compared. Compared to white patients (n = 17), Black individuals (n = 53) had lower systolic blood pressures (110 vs 131 mmHg, <0.001), reduced pulse pressures (41 vs 58 mmHg; P < 0.001), and impaired renal function (eGFR 46 vs 67 mL/min/1.73m2; P < 0.001) at presentation. Systolic properties and arterial elastance were similar. Black patients had end-diastolic pressure-volume relationships that were shifted upward and leftward relative to those of white patients, indicating reduced left ventricular chamber capacitance. Pressure-volume area at a left ventricular end-diastolic pressure of 30 mmHg was lower in Black than in white individuals (8055 mmHg/mL vs 11,538 mmHg/mL; P = 0.008). Despite presenting at ages similar to those of white patients, Black individuals with Val122Ile-associated ATTR-CA had a greater degree of cardiac chamber dysfunction at the time of diagnosis due to impaired ventricular capacitance. Whether these differences are attributable to amyloidosis or other cardiovascular disease requires further study.

Biventricular Compared to Left Ventricular Impella and Norepinephrine Support in a Porcine Model of Severe Cardiogenic Shock.

Contemporary management of cardiogenic shock (CS) with vasopressors is associated with increased cardiac workload and despite the use of unloading devices such as the Impella pump, concomitant vasopressors are often necessary. Therefore, we compared if cardiac workload could be reduced and end-organ perfusion preserved with biventricular support (Bipella) compared to ImpellaCP and norepinephrine in pigs with left ventricular (LV) CS caused by left main coronary microembolization. Cardiac workload was calculated from heart rate × ventricular pressure-volume area obtained from conductance catheters placed in the LV and right ventricle (RV), whereas organ perfusion was measured from venous oxygen saturation in the pulmonary artery (SvO 2 ) and the kidney- and the cerebral vein. A cross-over design was used to access the difference after 30 minutes of ImpellaCP and norepinephrine 0.1 µg/kg/min versus Bipella for 60 minutes. Bipella treatment reduced LV workload ( p = 0.0078) without significant difference in RV workload from ImpellaCP and norepinephrine, however a decrease in SvO 2 (49[44-58] vs . 66[63-73]%, p = 0.01) and cerebral venous oxygen saturations (62[48-66] vs . 71[63-77]%, p = 0.016) was observed during Bipella compared to ImpellaCP and norepinephrine. We conclude that Bipella reduced LV workload but did not preserve end-organ perfusion compared to ImpellaCP and norepinephrine in short-term LV CS.

Sex related differences in exercise performance in patients with hypertrophic cardiomyopathy: Hemodynamic insights through non-invasive pressure volume analysis

BackgroundWomen with HCM have worse cardiopulmonary exercise performance compared to men. We used non-invasive pressure-volume (PV) analysis to delineate sex related hemodynamic differences in HCM. MethodsPV loops were constructed from echocardiograms using left ventricular (LV) volumes indexed to body surface area, Doppler estimates of LV end-diastolic pressure and blood pressure. The end-systolic PV relationship (ESPVR) and end-diastolic PV relationship (EDPVR) were derived from validated single-beat techniques. The area between the ESPVR and EDPVR (isovolumetric PV area), was indexed to an LV end-diastolic pressure of 30 mmHg (PVAiso30), as the integrated metric of LV function. LV volume at an end-diastolic pressure of 30 mmHg (V30) indexed ventricular capacity. Results202 patients were included, 56 women. Women were older (51 vs 44 years, p = 0.012) and had reduced exercise capacity (5.6 vs 6.9 METs, p < 0.001). Only 32 patients (16%) had a peak gradient >30 mmHg at rest with no sex differences. Women had significantly lower indexed PVAiso30 (9094 vs 10,255 mmHg*mL/m2, p = 0.02) driven by reduced ventricular capacitance (V30 54 vs 62 mL/m2, p < 0.001). In multivariable linear regression indexed V30 was an independent predictor of exercise capacity. ConclusionImpaired exercise capacity in women with HCM appears associated with abnormalities in passive diastolic properties, suggesting a unique pathophysiology compared to men, and a potential difference in viable therapeutic molecular targets.

158 Racial differences in val122Ile associated transthyretin cardiac amyloidosis

Abstract Aims The valine-to-isoleucine substitution (Val122Ile) is the most common variant of transthyretin (TTR) amyloidosis in the USA, primarily affecting individuals of African descent and leading to a restrictive cardiomyopathy. This variant has recently been identified in a cluster of White individuals in Italy. In this study we aimed to investigate differences in the clinical phenotype of Val122Ile associated TTR cardiac amyloidosis (ATTR-CA) between Black and White individuals. Methods and results In this retrospective study of 70 patients (mean age 72 years) with Val122Ile associated TTR ATTR-CA, cardiac chamber performance was compared using noninvasive pressure-volume analysis. Compared to White patients (n = 17), Black individuals (n = 53) had lower systolic blood pressures (110 vs. 131 mmHg, P &amp;lt; 0.001), reduced pulse pressures (41 vs. 58 mmHg, P &amp;lt; 0.001), and impaired renal function (eGFR 46 vs. 67 mL/min/1.73 m2, P &amp;lt; 0.001) at presentation. Systolic properties and arterial elastance were similar. Black patients had an end-diastolic pressure-volume relationship shifted upward and leftward relative to White patients, indicating reduced left ventricular chamber capacitance. Pressure-volume area at a left ventricular end-diastolic pressure of 30 mmHg was lower in Black compared to White individuals (8055 mmHg*ml vs. 11 538 mmHg*ml, P = 0.008). Conclusions Despite presenting at a similar age to White patients, Black individuals with Val122Ile associated ATTR-CA have a greater degree of cardiac chamber dysfunction at the time of diagnosis due to impaired ventricular capacitance. Whether these differences are attributable to amyloidosis or other cardiovascular disease requires further study.

Atrial Septostomy for Left Ventricular Unloading During Extracorporeal Membrane Oxygenation for CardiogenicShock: Animal Model.

The aim of this study was to quantify and understand the unloading effect of percutaneous balloon atrial septostomy (BAS) in acute cardiogenic shock (CS) treated with venoarterial (VA) extracorporeal membranous oxygenation (ECMO). In CS treated with VA ECMO, increased left ventricular (LV) afterload is observed that commonly interferes with myocardial recovery or even promotes further LV deterioration. Several techniques for LV unloading exist, but the optimal strategy and the actual extent of such procedures have not been fully disclosed. In a porcine model (n=11; weight 56kg [53-58 kg]), CS was induced by coronary artery balloon occlusion (57minutes [53-64 minutes]). Then, a step-up VA ECMO protocol (40-80mL/kg/min) was run before and after percutaneous BAS was performed. LV pressure-volume loops and multiple hemoglobin saturation data were evaluated. The Wilcoxon rank sum test was used to assess individual variable differences. Immediately after BAS while on VA ECMO support, LV work decreased significantly: pressure-volume area, end-diastolic pressure, and stroke volume to ∼78% and end-systolic pressure to ∼86%, while superior vena cava and tissue oximetry did not change. During elevating VA ECMO support (40-80mL/kg/min) with BAS vs without BAS, we observed 1) significantly less mechanical work increase (122% vs 172%); 2) no end-diastolic volume increase (100% vs 111%); and 3) a considerable increase in end-systolic pressure (134% vs 144%). In acute CS supported by VA ECMO, atrial septostomy is an effective LV unloading tool. LV pressure is akey component of LV work load, so whenever LV work reduction is a priority, arterial pressure should carefully be titrated low while maintaining organ perfusion.

Abstract 9439: Invasive Evaluation of Left Ventricular Hemodynamics with Veno-Arterial Extracorporeal Membrane Oxygenation

Introduction: Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is a frequently used hemodynamic support strategy, but considerable debate exists about its hemodynamic effects. We evaluated changes in left ventricular (LV) function, volumes, and work in patients treated with VA-ECMO using invasive LV catheterization and three-dimensional echocardiographic volumes. Methods: In this case series, patients underwent evaluation due to persistent vasoplegia or poor LV function despite treatment with VA-ECMO. Hemodynamic parameters were reported as medians with interquartile ranges. Paired comparisons were done to evaluate hemodynamics at the baseline (highest) and lowest tolerated levels of VA-ECMO support. Results: Six patients aged 53.5 (41.8, 57.8) years were included. Three patients received VA-ECMO for refractory cardiogenic shock and three patients for extracorporeal cardiopulmonary resuscitation. The baseline LV ejection fraction was 22.1% (19.0%, 24.7%). The baseline and lowest VA-ECMO flows were 4.0 (4.0, 4.0) L/min and 1.0 (1.0, 1.5) L/min, respectively. Compared to the lowest flow, full VA-ECMO support reduced LV end-diastolic volume [116 (90, 153) versus 94 (58, 119) mL, p=0.03], LV end-diastolic pressure [16 (12, 24) versus 14 (9,15) mmHg, p=0.03], LV stroke work [2640 (1800, 4275) versus 1953 (759, 2179) mL*mmHg, p=0.03], and pressure-volume area [6864 (4038, 7715) versus 4575 (3142, 5888) mL*mmHg; p=0.046], respectively. The pressure-volume curves at the highest and lowest VA-ECMO flows are represented in blue and red, respectively ( Figure ). Mean arterial pressure and heart rate were similar at the lowest and highest flows (p=0.17 and p=0.60, respectively). All patients were decannulated from VA-ECMO. Four survived the index hospitalization. Conclusion: High flow VA-ECMO support significantly reduced LV end-diastolic volume, end-diastolic pressure, stroke work, and pressure-volume area compared to low flow.

Abstract 9321: Cardiac Work and End-Organ Perfusion During Biventricular Compared to Left Ventricular Impella and Norepinephrine Support in a Porcine Model of Severe Cardiogenic Shock

Background: Vasopressors are often combined with left ventricular (LV) mechanical support in severe cardiogenic shock to increase end-organ perfusion. Biventricular mechanical support might improve end-organ perfusion at lower cardiac workload compared to LV mechanical support and vasopressor infusion in severe cardiogenic shock. Aim: To compare LV and right ventricular (RV) total cardiac work (pressure-volume area x heart rate x 10 3 ) and organ-specific venous oxygen saturations from the pulmonary artery (SvO 2 ), kidney- and cerebral- veins in pigs with cardiogenic shock treated with biventricular (Bipella) versus ImpellaCP + norepinephrine 0.10 μg/kg/min (Imp+NE). Methods: Cardiogenic shock was induced by injections of microspheres into the left main coronary artery in eight pigs (approx. 70 kg). From conductance catheters in both ventricles, cardiac workload was calculated, and oxygen saturations were attained from the pulmonary artery, internal jugular- and kidney vein. Pigs were allocated in a crossover model to Bipella for 60 minutes (n=4) or Imp+NE for 30 minutes (n=4) and after completion shifted to the opposite treatment. Results are presented as median(Q1;Q3). Results: Bipella effectively unloaded the LV with reduction in LV work compared to Imp+NE (569[410-685] vs 357[206-509] 10 3 ml x mmHg/min, p=0.0078) while RV work was comparable (p=0.74). A significant increase in SvO 2 (66[63-73] vs 49[44-58]%, p=0.01) and cerebral venous oxygen saturations (71[63-77] vs 62[48-66]%, p=0.016) was observed during Imp+NE compared to Bipella, whereas no difference in kidney oxygen saturations was demonstrated (p=0.31). Conclusion: In this porcine study of cardiogenic shock due to left main coronary ischemia, Bipella decreased LV workload, but systemic oxygen delivery was not optimal (Figure). Imp+NE provided a higher LV workload balanced by an improvement in cerebral- and mixed venous oxygen saturation.

Automated non-invasive pressure-volume loop analysis of cardiac aging in a large cohort of healthy community dwellers

Abstract Background/Introduction Pressure-volume loops (PVloops) provide a wealth of information on cardiac function that is not readily available from cardiac imaging alone. Methods To estimate left ventricular (LV) PVloops non-invasively have been available, but have so far not been used to interrogate ventricular function in large patient cohorts, due to the complexity of estimating PVloops. A new method was recently validated that construct PVloops non-invasively from cine cardiac magnetic resonance (CMR), based on the time-varying elastance model [1]. At the same time, we have validated a framework for automated, quality controlled analysis of cine CMR in large cohorts of patients/subjects [2]. Combining these two methods could automated PVloop estimation, enabling analysis of ventricular pressure-volume relationships in large study populations. Purpose Evaluate if CMR-based non-invasive PVloops can be used to interrogate the impact of cardiac ageing on LV function occurring in a large population of healthy community dwellers. Methods Non-invasive PVloops were calculated from a full cardiac cycle LV volume curve and brachial blood pressure data using a recently validated method based on the time-varying elastance model [1], in 7,650 healthy community dwellers from the UKBiobank population study. The LV volume curve was automatically obtained using our state-of-the-art, quality controlled deep learning (DL) based cine CMR analysis framework [2]. External Work, pressure-volume-area (PVA), end-systolic pressure (Pes), ventricular elastance (Ees, an estimate of contractility) and arterial elastance (Ea) and energy per ejected volume (EEV: PVA/ stroke volume) were calculated from the PVloops. We performed univariate regression between PVloop parameters and age. We also calculated the additional impact of cardiovascular risk-factors in a multivariate analysis. Results See results in table 1. With age, LV volumes fall (p&amp;lt;0.001) in healthy subjects, while systolic blood pressure and Pes increases (both p&amp;lt;0.001). As a result of the higher afterload, PVA (p=0.894) and EW (p=0.499) do not significantly change with age despite a lower SV. Arterial elastance (Ea) increased, and so did contractility, as measured by Ees (p&amp;lt;0.001). Due to all these changes, EEV increased with age (p&amp;lt;0.001). In multivariate analysis, cardiovascular risk factors hypercholesterolemia and hypertension negatively impacted Pes, PVA, Ees and EEV. Diabetes and smoking habits did not. Conclusion Non-invasive CMR-based PVloop analyses capture the impact of known changes occurring during cardiac ageing on cardiac work, contractility and energetic expenditure. Obtaining PVloops automatically using our AI analysis system in this large cohort of healthy subjects allows to formulate reference for assessment of cardiac disease. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The authors acknowledge financial support (support) the National Institute for Health Research (NIHR) Cardiovascular MedTech Co-operative (previously existing as the Cardiovascular Healthcare Technology Co-operative 2012 - 2017) award to the Guy's and St Thomas' NHS Foundation Trust, in partnership with King's College London and the NIHR comprehensive Biomedical Research Centre of the Guy's &amp; St Thomas' NHS Foundation Trust. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health Univariate regression analysisExample of estimated PV loop

Sex related differences in exercise performance in patients with hypertrophic cardiomyopathy: hemodynamic insights through non-invasive pressure volume analysis

Abstract Background Women with HCM have worse cardiopulmonary exercise performance compared to men. We used non-invasive pressure-volume (PV) analysis to delineate sex related hemodynamic differences in HCM. Methods PV loops were constructed from echocardiograms using left ventricular (LV) volumes indexed to body surface area, Doppler estimates of LV end-diastolic pressure and blood pressure. The end-systolic PV relationship (ESPVR) and end-diastolic PV relationship (EDPVR) were derived from validated single-beat techniques. The area between the ESPVR and EDPVR (isovolumetric PV area), was indexed to an LV end-diastolic pressure of 30mmHg (PVAiso30), as the integrated metric of LV function. LV volume at an end-diastolic pressure of 30mmHg (V30) indexed ventricular capacity. Results 202 patients were included, 56 women. Women were older (51 vs 44 yrs, p=0.012) and had reduced exercise capacity (5.6 vs 6.9 METs, p&amp;lt;0.001). Only 32 patients (16%) had a peak gradient &amp;gt;30mmHg at rest with no sex differences. Women had significantly lower indexed PVAiso30 (6577 vs 7767 mmHg·mL/m2, p&amp;lt;0.001) driven by reduced ventricular capacitance (V30 54 vs 62 ml/m2, p&amp;lt;0.001). In multivariable linear regression indexed V30 was an independent predictor of exercise capacity. Conclusion Impaired exercise capacity in women with HCM appears strongly related to abnormalities in passive diastolic properties, suggesting a unique pathophysiology compared to men, and a potential difference in viable therapeutic molecular targets Funding Acknowledgement Type of funding sources: None.

An Improved Heap-Based Optimizer for Optimal Design of a Hybrid Microgrid Considering Reliability and Availability Constraints

The hybrid microgrid system is considered one of the best solution methods for many problems, such as the electricity problem in regions without electricity, to minimize pollution and the depletion of fossil sources. This study aims to propose and implement a new algorithm called improved heap-based optimizer (IHBO). The objective of minimizing the microgrid system cost is to reduce the net present cost while respecting the reliability, power availability, and renewable fraction factors of the microgrid system. The results show that the PV/diesel/battery hybrid renewable energy system (HRES) gives the best solution, with a net present cost of MAD 120463, equivalent to the energy cost of MAD 0.1384/kWh. The reliability is about 3.89%, the renewable fraction is about 95%, and the power availability is near to 99%. The optimal size considered is represented as 167.3864 m2 of PV area, which is equivalent to 44.2582 kW and 3.8860 kW of diesel capacity. The study results show that the proposed optimization algorithm of IHBO is better than the artificial electric field algorithm, the grey wolf optimizer, Harris hawks optimization, and the original HBO algorithm. A comparison of the net present cost with a different fuel price is carried out, in which it is observed that the net present cost is reduced even though its quantity used is mediocre.