Loop Analysis Research Articles

One step closer to myocardial physiology: From PV loop analysis to state-of-the-art myocardial imaging.

Recent advances in cardiac imaging have revitalized the assessment of fundamental physiological concepts. In the field of cardiac physiology, invasive measurements with pressure-volume (PV) loops have served as the gold standard methodology for the characterization of left ventricular (LV) function. From PV loop data, fundamental aspects of LV chamber function are derived such as work, efficiency, stiffness and contractility. However, the parametrization of these aspects is limited because of the need for invasive procedures. Through the utilization of recent advances in echocardiography, magnetic resonance imaging and positron emission tomography, it has become increasingly feasible to quantify these fundamental aspects of LV function non-invasively. Importantly, state-of-the-art imaging technology enables direct assessment of myocardial performance, thereby extending functional assessment from the net function of the LV chamber, as is done with PV loops, to the myocardium itself. With a strong coupling to underlying myocardial physiology, imaging measurements of myocardial work, efficiency, stiffness and contractility could represent the next generation of functional parameters. The purpose of this review is to discuss how the new imaging parameters of myocardial work, efficiency, stiffness and contractility can bring cardiac physiologists, researchers and clinicians alike one step closer to underlying myocardial physiology.

O-Minimal Invariants for Discrete-Time Dynamical Systems

Termination analysis of linear loops plays a key rôle in several areas of computer science, including program verification and abstract interpretation. Already for the simplest variants of linear loops the question of termination relates to deep open problems in number theory, such as the decidability of the Skolem and Positivity Problems for linear recurrence sequences, or equivalently reachability questions for discrete-time linear dynamical systems. In this article, we introduce the class of o-minimal invariants , which is broader than any previously considered, and study the decidability of the existence and algorithmic synthesis of such invariants as certificates of non-termination for linear loops equipped with a large class of halting conditions. We establish two main decidability results, one of them conditional on Schanuel’s conjecture is transcendental number theory.

Participatory Causal Loop Mapping of the Adoption of Organic Farming in Nigeria.

Contrary to the expectations of promoters of organic agriculture, the adoption of the technology by smallholder farmers in Africa has been low and slow, for reasons not well understood. Existing studies on the topic mostly estimated the effect of some variables on the adoption of the technology. But adoption is characterized by complex and dynamic interactions of many interconnected factors, which existing studies overlooked. The underlying causal structures and feedback mechanisms that dynamically interact to affect the adoption of organic farming in urban and rural Africa are also not well known. To bridge these gaps, we used a system dynamics tool called participatory causal loop diagraming to map the underlying causal factors and feedback mechanisms driving the adoption of organic farming in rural and urban Nigeria. We conducted loop and network analyses of the group causal loop diagrams, which were created during the participatory system dynamics modeling workshops with the organic farmers in our study areas. Our findings underscore the importance of the knowledge of organic farming, demand- and supply-side-oriented awareness creation, and the economic viability of organic farming for widespread adoption of the technology. We suggested the potential leverages around which interventions can be built to boost the adoption rates of the technology.

Identifying stakeholders’ perspectives on the success factors of halal tourism in the city of Makassar: a group model building approach

Purpose Islamic attributes and activities need to be developed in compliance with the halal concept to attract potential Muslim tourists and ensure the success of halal tourism. Although the literature shows that many factors can influence the success of halal tourism, a complete picture of the success factors of halal tourism in a city is still very limited. As such, this explorative study aims to examine stakeholders’ perspectives regarding the antecedents of halal tourism success and the benefits of halal tourism for the city. Design/methodology/approach Qualitative system dynamics modeling was used for this study, and Makassar (a successful halal tourism city) was considered as the basis for the study. A causal loop diagram (CLD) of halal tourism was developed using the group model building technique to elicit stakeholders’ knowledge and assumptions. Network analysis and feedback loop analysis were used to identify the driving factors of successful halal tourism. Findings Two factors need to be taken into account by halal tourism stakeholders in the city: support from the central and local government and improving and maintaining potential tourists’ perceptions of the city. There are four benefits of halal tourism success for the city: an increase in the number of micro-, small- and medium-sized halal businesses in the city, increased support from the central and local government to further develop halal tourism infrastructure in the city, increased word-of-mouth promotion of Makassar as a tourism destination and a decrease in the price of halal tourism components (e.g. food and accommodation). Originality/value The resulting CLD shows the interlinkage between political, societal and economical factors that could influence the success of halal tourism development. In particular, the findings show how governments and tourism stakeholders need to promote halal tourism socialization in the community and improve the public perception of this type of tourism. Therefore, the findings can help destination stakeholders and tourism developers in other cities develop halal tourism potential.

Boom, Bust, and Bitcoin: Bitcoin-Bubbles as Innovation Accelerators

Bitcoin represents one of the most interesting technological breakthroughs and socio-economic experiments of the last decades. In this paper, we examine the role of speculative bubbles in the process of Bitcoin’s technological adoption by analyzing its social dynamics. We trace Bitcoin’s genesis and dissect the nature of its techno-economic innovation. In particular, we present an analysis of the techno-economic feedback loops that drive Bitcoin’s price and network effects. Based on our analysis of Bitcoin, we test and further refine the Social Bubble Hypothesis, which holds that bubbles constitute an essential component in the process of technological innovation. We argue that a hierarchy of repeating and exponentially increasing series of bubbles and hype cycles, which has occurred over the past decade since its inception, has bootstrapped Bitcoin into existence.

A technical and data analytic approach to pressure-volume loops over numerous cardiac cycles

Cardiac pressure-volume (PV) loop analysis is the reference standard for studying the cardiovascular implications of clinical perturbations (eg, heart failure, aortic occlusion, hypovolemia) and is a benchmark for comparisons with noninvasive alternatives (eg, ultrasound, magnetic resonance imaging). Historically, most PV loop analyses were of individual cardiac cycles for which the options to analyze PV loops using off-the-shelf software were limited, and home-grown analysis software often lacked peer review or code-sharing. Our aim was to describe a start-to-finish implementation of PV loops for determination of hemodynamic parameters in swine, to provide technical advice for vascular access and proceduralization, and to describe data capture, curation, preprocessing, and analysis of raw PV time data. We have provided a novel data analytic method to programmatically analyze raw PV loop data beyond single cardiac cycles and real, raw swine PV loop data and the accompanying MATLAB (MathWorks, Inc, Natick, Mass) code as an example of how to process and analyze raw data directly.

Impact of Acute Ischemia-Reperfusion Injury on Left Ventricular Pressure-Volume Relations in Dogs

Objective: Ischemic conditioning (IC) limits myocyte necrosis after acute myocardial ischemia-reperfusion; however, controversy persists regarding its potential to attenuate LV contractile dysfunction. Pressure-volume (P-V) loop analysis, via the load-insensitive conductance catheter method, was used to evaluate LV contractility, diastolic function, and ventriculo-arterial coupling. The goal of this study was to evaluate the ability of IC to improve post-ischemic recovery of LV contractile function. Methods: Twelve anesthetized dogs were randomly distributed to either the IC or the non-IC group; all dogs were subject to 60-min acute coronary occlusion followed by 180-min reperfusion. IC consisted of 4 repeated cycles of 5-min occlusion and 5-min reperfusion of the left main coronary artery. LV P-V relations were constructed under steady-state conditions (by inferior vena cava occlusion) at the beginning and end of the experiments; P-V loops were acquired at different time points before and during ischemia-reperfusion. Results: During ischemia and reperfusion, dP/dtmax decreased significantly compared to baseline in both groups; dP/dtmin, an indicator of the rate of LV relaxation rate was not affected for either group. Significant changes in several parameters of LV function including LVEF, SW, tPFR, ESV, and EDV caused by ischemia were also identified; none of these negative effects were resorbed, even in part, during reperfusion. Conclusions: Diminished LV contractile efficiency during systole and diastole produced by ischemia-reperfusion did not improve with IC pre-treatment despite significant endogenous protection against tissue necrosis.

Ant Colony Optimization Tuned Closed-Loop Optimal Control Intended for Vehicle Active Suspension System

In recent years, the suspension system in modern vehicles has played a key role both as far as driving safety and comfort is concerned. To satisfy these vehicle performance specifications, active suspension is currently studied and implemented in practice in recent decades. In contrast to passive suspensions, by introducing force into system, active suspension can alter the suspension dynamic in real-time. A design of a controller is needed for real-time tuning of the control force in an active suspension system (ASS) to fulfill the challenging control objectives of suspension system comprising road handling, ride convenience, and travel suspension. This research proposed a novel ant colony optimization (ACO) algorithm for solving multi-objective weight optimization problem of the linear quadratic regulator (LQR) for automobiles ASS. The optimization problem of ASS is to design a state-feedback controller (SFC) as a result ACO is used to find optimal LQR weights. Here both Q and R weight matrix of LQR is tuned. On a quarter-car ASS (QCASS) system, the effectiveness of ACO-tuned LQR is analytically checked with hardware in loop (HIL) analysis for an irregular road surface. Here, for experiment, ISO road D rough runway, bumpy path, and pulse-type road profile are taken into account. Experimental findings illustrate that the proposed procedure can substantially reduce the acceleration of the Car body due to irregular road profiles compared to classical tuned LQR and model predictive control (MPC). The proposed controller shows the profound impact on the efficiency of the control schemes for three different road profiles.

Low Cycle Fatigue Behavior of Al-Mg-Si Alloys Extruded Parts

Over the past years, Al-Mg-Si alloys have been largely applied in automotive industry, which has required a deep knowledge of their mechanical properties and the influence of precipitates distribution on their mechanical behavior. This work evaluated the main mechanical properties of AA6005, AA6063, and AA6351 alloys by means of tensile and low cycle fatigue tests with 0.005 seg-1 deformation rate and 0.3% < εat <1.2% strain amplitudes. Besides, the hysteresis loop and internal stress analysis were investigated to analyze hardening and softening phenomena and to evaluate the friction and back stresses, respectively. Macro and microstructural were performed focusing in intermetallic distribution. Concerning the low cycle fatigue behavior, AA6351 presented shorter lives for strain amplitudes higher than 0.5%, and AA6005 showed the highest fatigue strength and fatigue ductility. AA6063 showed the lowest fatigue strength due to the presence of coarse particles (Fe,Mn)SiAl. During internal stress analysis, the highest value of friction stress for AA6351 indicates the effect of hardener precipitates are the most relevant role for cyclic loadings and the lowest back-to-friction stress ratio indicating that deformation is controlled by particles. In the other hand, AA6063 showed the lowest friction stress due to low amount of fine precipitates.

Hybrid-Mode PFM Control for LLC Resonant Converter

This article presents a new hybrid-mode pulse-frequency-modulation control method for an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> resonant converter. In the proposed control method, the primary-side resonant current sensing signal of the current-mode control variable is combined with a ramp signal of the voltage-mode control variable to determine an operating frequency. Then, the proposed control method mainly modulates the ramp signal in accordance with the output load condition. Therefore, the control-to-output voltage transfer function has both the current <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-</b> mode control and voltage-mode control characteristics that provide fast frequency response and stable output voltage regulation in a light-load condition. In addition, since the ramp signal is also used for slope compensation of the resonant current sensing signal, an external slope compensation circuit is not required. A small-signal ac modeling and loop analysis of the proposed method verify the advantages. The proposed control method is implemented into a field programmable gate array (FPGA) board with an analog front-end board. An experiment is carried out on a 288-W <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> resonant converter. The result shows that the proposed control method provides fast dynamic performance and stable operation under a light-load condition without an additional slope compensation circuit.

Invasive Right Ventricular Pressure-Volume Analysis: Basic Principles, Clinical Applications, and Practical Recommendations.

Right ventricular pressure-volume (PV) analysis characterizes ventricular systolic and diastolic properties independent of loading conditions like volume status and afterload. While long-considered the gold-standard method for quantifying myocardial chamber performance, it was traditionally only performed in highly specialized research settings. With recent advances in catheter technology and more sophisticated approaches to analyze PV data, it is now more commonly used in a variety of clinical and research settings. Herein, we review the basic techniques for PV loop measurement, analysis, and interpretation with the aim of providing readers with a deeper understanding of the strengths and limitations of PV analysis. In the second half of the review, we detail key scenarios in which right ventricular PV analysis has influenced our understanding of clinically relevant topics and where the technique can be applied to resolve additional areas of uncertainty. All told, PV analysis has an important role in advancing our understanding of right ventricular physiology and its contribution to cardiovascular function in health and disease.

Tailoring magnetic and dielectric properties of SrFe12O19/NiFe2O4 ferrite nanocomposites synthesized in presence of Calotropis gigantea (crown) flower extract

SrFe12O19 (M-type hexaferrite) and NiFe2O4 (spinel) nano ferrite powders were synthesized in the presence of Calotropis gigantea (crown) flowers extract separately. SrFe12O19/NiFe2O4 nanocomposites were prepared in the presence of crown flowers extract and the effect of different weight ratios (M:S – 9:1, 8:2, 7:3, 6:4, 5:5) on structural, microstructural, magnetic, electrical transport, and dielectric properties were studied. The average crystallite size of nanocomposites was found from 25 nm to 44 nm. In addition, it was observed that the crystallite size of the M-phase decreased when the spinel phase increased. XRD analysis depicts the presence of both M and S phases in composites. The M-H loops analysis of SrFe12O19/NiFe2O4 composites indicates that the coercivity (3181–326 Oe), and saturation magnetization (57.5 Am2/kg. - 40 Am2/kg.) decreased when the spinel phase amount increased. Nanocomposites with weight ratios 9:1, 8:2, 7:3, 6:4 belong to a hard ferrite, while 5:5 shows soft magnetic nature. However, prepared composites possess a multi-domain structure. The weak exchange coupling interactions were found in composites 9:1 and 8:2, whereas the partial exchange coupling interactions were observed in composites 7:3, 6:4, and perfect exchange coupling interaction was noticed in 5:5.

Transcutaneous electrical stimulation therapy and genetic analysis in Dercum's disease: A pilot study.

Dercum's disease (DD), or adiposis dolorosa, is a rare condition of unknown etiology characterized by growth of painful subcutaneous adipose tissue. No specific treatment exists. Pain is often invalidating and resistant to analgesic drugs. We tested the efficacy of Frequency Rhythmic Electrical Modulation System (FREMS) therapy on pain relief. Subcutaneous biopsies were performed for genetic analysis.Nine DD patients were enrolled. Five cycles of FREMS at 3-month intervals during 1 year were administered. Visual analogue scale (VAS), Bartel Index Questionnaire and Short Form 36 questionnaire were used to measure pain and general health status at baseline, 6 and 12 months. Dual-energy X-ray absorptiometry (DEXA) quantified fat mass. Next-Generation Sequencing (NGS) was performed on adipose tissue biopsies and peripheral blood sample to search for somatic variants and specific protein pathway mutation.Seven patients were included in the final analysis. FREMS induced a reduction in VAS score (from 92 to 52.5, P = .0597) and a significant improvement in SF-36 domains (Physical functioning, Role limitation due to physical health, Body pain, Vitality, Social functioning, P < .05). No modification in anthropometrics and DEXA values was observed. The analysis of the mitochondrial Displacement loop (D-loop) region confirmed the clonality of all lipomatous lesions. The presence of the mitochondrially encoded tRNA-Lysine (MT-TK) m.8344A>G variant, occasionally identified in patients with multiple symmetric lipomatosis, was excluded in all subjects. On the other hand, we observed variants in genes belonging to signaling pathways involved in cell cycle and proliferation (Phosphoinositide 3-kinase/AKT/mTOR, MAPK/ERK, and Hippo).FREMS can be a useful tool to alleviate pain and improve overall quality of life in patients with DD. Genetic analysis highlighted the molecular heterogeneity of lipomas.

Investigating flood processes in karst catchments by combining concentration-discharge relationship analysis and lateral flow simulation

Concentration-Discharge (C-Q) relationship analyses allow better understanding catchment water origin and hydrological process variability across time (from storm-event to pluriannual scale). Though, those approaches mostly include integrative methods that consider catchments as a whole. The aim of this article is to assess the potential of a combined approach to investigate the spatio-temporal variability of flood processes within catchments (across river reaches and seasons), focusing on karst areas. The methodology consists in combining C-Q relationship analysis in nested catchments and simulation of lateral exchanges at the reach scale. For that, we analyze high-frequency records of discharge and electrical conductivity (EC) in karst catchments, in which EC informs on water residence time. Contributions of pre-event water (PEW) and event water (EW) during storm events are investigated through hysteresis loop analysis at each gauging station. Combined with lateral EC simulation at the reach scale, they make it possible to infer runoff processes during storms. A unary karst catchment in a temperate/mountainous climate (Loue River) and a binary catchment in a Mediterranean climate (Cèze River) were selected in France, and their conceptual models of water origin and hydrological process variability were drawn. In the Loue catchment, summer and fall storm events are characterized by contributions of PEW through piston-type flows, whereas decreasing EC values in winter and spring storm events indicate the major contribution of EW through surface runoff and fast infiltration. Within the catchment, EW contribution increases downstream, due to the canyon river morphology grading into open valleys. Regarding the Cèze catchment, contributions of EW are higher, indicating that fast infiltration and surface runoff are the dominant processes, associated with a PEW signature in summer and fall. Within the catchment, PEW contribution is found higher in karstified areas. These results show that flood process seasonality is mainly related to karst aquifer saturation rate, while intra-site variability is linked to karst area extension and river morphology. Results are encouraging to extend this approach to a variety of sites, notably those affected by significant surface water-groundwater interaction and groundwater flooding. Such approach, by providing a discretized information on flood processes, could help refining lumped hydrological models, or facilitate the use of semi-distributed ones.

Enhancing breakdown strength and lifetime of multilayer dielectric films by using high temperature polycarbonate skin layers

Polymer multilayer films (MLFs) hold a potential to achieve high energy density, high temperature rating, and high breakdown strength simultaneously for next-generation film capacitors. Under extreme conditions such as high AC electric fields and high temperatures, an important dielectric loss mechanism is the homocharge injection from metal electrodes and subsequent charge recombination (i.e., AC electronic conduction) at the electrode/dielectric interfaces. In this work, the mechanism of the AC electronic conduction loss is studied for high-temperature polycarbonate (HTPC)/poly(vinylidene fluoride) (PVDF) MLFs with either HTPC (MLF@HTPC) or PVDF skin layers (MLF@PVDF). Based on the DC/AC breakdown strength and lifetime measurements, it is observed that homocharge injection was more significant for MLF@PVDF than MLF@HTPC. Using the electric displacement-electric field loop analysis, dielectric losses from both AC electronic conduction and ferroelectric switching (PVDF) are quantified. A dipolar electric double layer model at the electrode/PVDF interfaces is proposed to explain the more significant ferroelectric switching and charge injection in MLF@PVDF. From these experimental results, it is concluded that enhanced breakdown strength and lifetime can be achieved for MLF@HTPC because of the reduced homocharge injection and AC electronic conduction at high electric fields and high temperatures.

Post-irradiation microstructural examination of EUROFER-ODS steel irradiated at 300°C and 400°C

The effect of neutron irradiation on the microstructure of EUROFER-ODS alloy reinforced with an addition of 0.5% Y 2 O 3 was analyzed by transmission electron microscopy . The irradiation of up to 16.2 dpa damage dose at 300°C and 400°C was performed in Petten High Flux Reactor. This study focuses on the imaging, identification, and quantitative analysis of interstitial loops and voids located on ODS particles. The nano-sized loops and point defects with b½〈111〉 Burgers vectors are preferentially located near structural defects such as the line dislocations or impurities in the material irradiated at 300°C. Homogeneously distributed loops having Burgers vectors of b½〈111〉 and b〈100〉 types were found in the material irradiated at 400°C. The obtained quantitative data on radiation-induced defects such as size, number density and relaxation volume were compared with EUROFER97 irradiated at the same conditions. It was found that the occurrence of radiation induced defects depends on the local number density and the size distribution of the ODS particles and not only on the irradiation damage and temperature.

Design and Analysis of CMOS Phase Lock Loop (PLL) Using VLSI Technology

Abstract: This paper proffers comparative research of Complementary MOSFET (CMOS) of the Phase Lock Loop (PPL) circuit. Our approach is based on hybrid design Phase Lock Loop (PLL) circuits combined in a single unit. A phase-locked loop (PLL) is used in space communication for synchronization purposes also very useful in time to digital converters and in instrumentation engineering. A phased lock loop (PLL) is a control system that makes an output signal whose frequency depends on the input phase difference. The phase detector takes the phase of an input signal and compares it with the phase procured from its output oscillator regulates the frequency of its oscillator to manage the phase matches. Different techniques like analogue and digital simulation with the help of mathematical/logical connections are found in Research to create the Phase Locked Loop (PLL). This limitation can be overcome by replicating the circuit block whose supply voltage is being reduced to manage the same throughout. This paper includes design features for low power phase-locked loop using Very-large-scale integration (VLSI) technology. The signal from the phase detector controls the oscillator in a feedback loop. As such: an operational device the PLL has a wide range of applications in computers sciences, telecommunication, and electronic system applications; we aim to design and examine the phase lock loop circuit in multiple technologies and examine their power capacity. By using the hybrid structure of NMOS and PMOS, here we have achieved the circuit of Phase Lock Loop (PLL) using VLSI technology. Keywords: Technology, CMOS, Phase lock loop, Micro wind, Voltage control oscillator, VLSI technology.

Revisiting stability analysis of Phase-Locked Loops with the Popov Stability Criterion

This paper revisits the problem of stability analysis of Phase-Locked Loops (PLLs), focusing specifically on stability conditions derived using the Popov Stability Criterion. A new form of the Popov based frequency domain criterion is derived in which the size of the stability region, the PLL locking range, appears independently of the loop transfer-function. This enables one to maximize the stability region graphically and directly on the Popov plot, rather than iteratively. Various numerical and analytic results available in the literature are shown to be particular cases of the proposed new stability test. It is also shown that for PLLs of type r, in which r denotes the number of integrators in the loop, it is not possible to achieve full locking range if r is larger or equal than three.

Abstract 10313: Gender and Strain Background Affect Cardiopulmonary Function in Col4a3 -/- Alport Mice

Background: Alport syndrome (AS) is a hereditary form of chronic kidney inflammation that results in renal failure (RF). We previously reported that Col4a3 -/- 129J mice, a model of AS and RF, exemplified multiple features of heart failure with preserved ejection fraction (HFpEF). This study investigates the effect of 3 different genetic backgrounds on cardiopulmonary function in Col4a3 -/- mice. Methods: Male and female Col4a3 -/- (Alport) and WT mice from 129x1/SvJ, C57Bl/6 and BALBC strain were examined using echocardiography, whole body plethysmography (WBP) and pressure-volume (PV) loop analysis. Ttest was used for statistical analysis. Four groups per strain were used (n= 4-15/group). Results: Compared with their respective age-matched WT controls, male and female 8-week-old Col4a3 -/- 129x1/SvJ mice demonstrated impaired systolic function (EF of 56 to 43.7%, p=.002 for females and 50.9 to 42% for males, p=.044; SV, CO, p&lt;.05) and diastolic dysfunction (increased IVRT from 15.3 to 21.7ms, p=.0009 for females; 16.6 to 26.2ms, p&lt;.0001 for males; increased MPI, P&lt;.05). Additionally, PV loop analysis showed an increased EDPVR and end diastolic pressure, prolonged time constant of LV relaxation, and decreased CO and SV (p&lt;0.05). For Col4a3 -/- BalbC and Col4a3 -/- C57Bl/6 strains, only females exhibited systolic (BalbC: EF% 51 to 45.66%, p=0.106 for females and 43.5 to 40.8% for males, p=.51; B6: EF% 51.3 to 40.8% p=.02 for females and 48.4 to 40.9%, p=.31 for males; SV, CO, p&lt;.05) and diastolic dysfunction (IVRT from 16 to 24.1ms for BalbC and 18.20 to 25.63ms for B6, p&lt;0.05). Male Col4a3 -/- BalbC had an increase in minimum and end-systolic pressures, and an increased pressure at dV/dt-max. Male Col4a3 -/- C57Bl/6 mice had an increased ESPVR slope (p&lt;.05). All strains except BalbC males demonstrated alterations (p&lt;.05) in pulmonary function including decreased ventilation rate (MV) and respiratory frequency, decreased peak expiratory flow, EF50, increased expiratory time, relaxation time, inspiratory time, and time of pause at end-of-expiration. Conclusion: Both male and female Col4a3 -/- 129x1/SvJ mice demonstrated impaired cardiopulmonary viability. However, Col4a3 -/- mice on BalbC or C57Bl/6 strains had cardiopulmonary deficits only in females.

Abstract 14237: Myocardial Work Indices by Pressure-Strain Loop Analyses Predict Cardiovascular Outcome in the General Population

Introduction: A novel tool to assess myocardial work by echocardiography has recently become available through pressure-strain loop (PSL) analyses. We sought to evaluate the prognostic value of non-invasive myocardial work indices in the general population. Methods: This was an echocardiographic substudy based on a prospective community-based cohort study (n=4,466). PSL analyses were performed to acquire myocardial work index (MWI), global constructive work (GCW), global wasted work (GWW), and myocardial work efficiency (MWE). The endpoint was a composite of heart failure or cardiovascular death (HF/CVD) at 5-years of follow-up. Multivariable logistic regression was applied to adjust for SCORE chart risk factors. Spline curves were constructed with Poisson regression. Results: A total of 3,896 participants were included in this analysis (mean age: 56 years, 43% men). Of these, 232 (6%) experienced the outcome within 5 years. Participants who experienced HF/CVD had reduced MWI (2202 vs. 2295mmHg%, p=0.001), reduced MWE (95.8 vs. 96.9%, p&lt;0.001), and higher GWW (95 vs. 73mmHg%, p&lt;0.001), whereas GCW was similar between outcome groups. In addition, decreasing MWI and MWE as well as increasing GWW was associated with a higher risk of HF/CVD in univariable analyses. After multivariable adjustments, however, all work parameters were associated with HF/CVD (MWI: OR=1.15 (1.10-1.19), per 100mmHg% decrease; GCW: OR=1.14 (1.10-1.19), per 100mmHg% decrease; GWW: OR=1.19 (1.05-1.34), per 50mmHg% increase; MWE: OR=1.14 (1.08-1.19), per 1% decrease). The risk of HF/CVD was curvilinear for MWI and GCW, whereas there was a linear association for GWW and MWE (figure). Conclusions: Myocardial work indices by PSL analysis are associated with 5-year risk of HF/CVD in a large-scale general population independently of clinical risk factors.