Relation between ventriculoarterial coupling and myocardial energetics in patients with idiopathic dilated cardiomyopathy

AbstractObjectives. The purpose of this study was to evaluate left ventricular contractility, arterial loading conditions and the way their interaction affects myocardial energetics.Background. Ventriculoarterial coupling, defined as the ratio of effective arterial elastance to left ventricular end-systolic elastance, is known to reflect the mechanoenergetic performance of the heart. However, relations between the coupling and efficiencies of energy transfer from oxygen consumption to hydraulic energy have not been fully investigated in failing hearts.Methods. Pressure-volume data were measured in 23 patients with idiopathic dilated cardiomyopathy by using a conductance catheter, and myocardial oxygen consumption was obtained simultaneously in 16 patients by a double-thermistor coronary sinus catheter. End-systolic elastance was determined by transient inferior cava occlusion.Results. Data are reported as mean value ± SE. Ventriculoarterial coupling at baseline was 3.14 ± 0.28. It decreased from 3.12 ± 0.43 to 1.86 ± 0.15 (p < 0.05) for the group receiving dobutamine infusion and from 3.16 ± 0.45 to 1.78 ± 0.22 (p < 0.01) for the group receiving the oral phosphodiesterase inhibitor MS-857. The ratio of pressure-volume area to myocardial oxygen consumption had a positive correlation with ventriculoarterial coupling. The ratio of external work to pressure-volume area had a hyperbolic correlation with the coupling. The mechanical efficiency defined as the ratio of external work to myocardial oxygen consumption remained within a narrow range (16.4 ± 1.2%).Conclusions. The degree of ventriculoarterial coupling is far from optimal and the cardiovascular performance is severely depressed mechanically and energetically in patients with idiopathic dilated cardiomyopathy. Although inotropic agents improve the coupling, they have a minimal effect on mechanical efficiency

Arsenic Contamination of Groundwater at the Middle Basin of Ganges in India

This paper shows the situation and mechanism of arsenic contamination of groundwater at the worst contaminated areas in UP (Uttar Pradesh) state, India, which is obtained from the integrated arsenic mitigation project by University of Miyazaki under the Japan International Cooperation Agency (JICA) Partnership Program (JPP). The project has been executed from 2008 until now. The integrated mitigation, such as the raising awareness of villager, installing of alternative water supply units and healthcare of arsenocosis patients, have been executed at the 2 villages. The symptom of the arsenocosis patients was not so severe, which will be, therefore, improved by drinking arsenic-safe water supplied through arsenic removal units, installed by this project. We have obtained following results for the situation and mechanism of arsenic contamination of groundwater, objected in connection with the installation of arsenic removal units:(1) Groundwater is almost contaminated with arsenic in deep tubewell (depth: about 30m), but scarcely in shallow tubewell (depth: about 10m). (2) Arsenic contaminated groundwater is under the reduced condition with the oxidized condition for no-arsenic contaminated groundwater. (3) Arsenic concentration shows almost linear correlation with concentrations of Fe2+ and NH4+-N. (4) Ground is composed of sand with high arsenic content at around 25m depth. (5) Arsenic exists mainly in the phase of reducible fraction or weak acid soluble fraction but no oxidizable fraction in the ground

Twenty barrel in situ pipe gun type solid hydrogen pellet injector for the Large Helical Device

A 20 barrel solid hydrogen pellet injector, which is able to inject 20 cylindrical pellets with a diameter and length of between 3.0 and 3.8 mm at the velocity of 1200 m/s, has been developed for the purpose of direct core fueling in LHD (Large Helical Device). The in situ pipe gun concept with the use of compact cryo-coolers enables stable operation as a fundamental facility in plasma experiments. The combination of the two types of pellet injection timing control modes, i.e., pre-programing mode and real-time control mode, allows the build-up and sustainment of high density plasma around the density limit. The pellet injector has demonstrated stable operation characteristics during the past three years of LHD experiments

Myocardial velocity gradient as a noninvasively determined index of left ventricular diastolic dysfunction in patients with hypertrophic cardiomyopathy

AbstractObjectivesWe investigated the utility of the peak negative myocardial velocity gradient (MVG) derived from tissue Doppler imaging (TDI) for evaluation of diastolic dysfunction in patients with hypertrophic cardiomyopathy (HCM).BackgroundHypertrophic cardiomyopathy is characterized by impaired diastolic function with abnormal stiffness and prolonged relaxation. However, it remains difficult to evaluate these defects noninvasively.MethodsBoth TDI and conventional echocardiography were performed in 36 patients with HCM and in 47 control subjects. Left ventricular (LV) pressure was measured simultaneously in all HCM patients and in 26 controls.ResultsThe peak negative MVG occurred soon after the isovolumic relaxation period during the initial phase of rapid filling (auxotonic relaxation). It was significantly smaller in HCM patients than in control subjects (2.32 ± 0.52/s vs. 4.82 ± 1.15/s, p < 0.0001); the cutoff value for differentiation between all HCM patients and 47 normal individuals was determined as 3.2/s. Both the left ventricular end-diastolic pressure (LVEDP) (19.6 ± 6.1 mm Hg vs. 6.5 ± 1.7 mm Hg, p < 0.0001) and the time constant of LV pressure decay during isovolumic diastole (tau) (44.0 ± 6.7 ms vs. 32.1 ± 5.5 ms, p < 0.0001) were increased in HCM patients compared with controls. The peak negative MVG was negatively correlated with both LVEDP (r= −0.75, p < 0.0001) and tau (r= −0.58, p < 0.0001).ConclusionsA reduced peak negative MVG reflects both prolonged relaxation and elevated LVEDP. The peak negative MVG might thus provide a noninvasive index of diastolic function, yielding unique information about auxotonic relaxation in patients with HCM

Development of UPS-SMES as a protection from momentary voltage drop

We have been developing the UPS-SMES as a protection from momentary voltage drop and power failure. The superconducting system is suitable as electric power storage for large energy extraction in a short time. The most important feature of superconducting coil system for the UPS-SMES is easy handling and maintenance-free operation. We have selected low temperature superconducting (LTS) coils instead of high temperature superconducting (HTS) coils from the viewpoint of cost and performance. However, it is difficult for the conventional LTS coils to fulfill maintenance-free operation since the cooling methods are either pool boiling with liquid helium or forced flow of supercritical helium. Thus, a conduction cooled LTS pulse coil has been designed as a key component of the UPS-SMES. The development program of 1 MW, 1 sec UPS-SMES is explained

Effects of gamma-ray irradiation on electronic and non-electronic equipment of Large Helical Device

In a deuterium operation on the Large Helical Device, the measurement and control equipment placed in the torus hall must survive under an environment of radiation. To study the effects of gamma-ray irradiation on the equipment, an irradiation experiment is performed at the Cobalt-60 irradiation facility of Nagoya University. Transient and permanent effects on a personal computer, media converters, programmable logic controllers, isolation amplifiers, a web camera, optical flow meters, and water sealing gaskets are experimentally surveyed. Transient noise appears on the web camera. Offset of the signal increases with an increase of the integrated dose on the programmable logic controller. The DeviceNet module on the programmable logic controller is broken at the integrated dose of 72 Gy, which is the expected range of the integrated dose of the torus hall. The other equipment can survive under the gamma-ray field in the torus hall

Development of 1 MJ Conduction-Cooled LTS Pulse Coil for UPS-SMES

A 1 MW, 1 s UPS-SMES is being developed for a protection from a momentary voltage drop and an instant power failure. As a key technology of the UPS-SMES, we developed a prototype LTS pulse coil with a stored energy of 100 kJ and conducted cooling and excitation tests in 2005. The operation test of the prototype UPS-SMES using this 100 kJ coil with power converters have been performed in 2006. A 1 MJ coil was designed before the fabrication of the 100 kJ prototype coil. The superconductor, the electric insulation technique, the winding method, and the cooling structure used for the 100 kJ coil were based upon the 1 MJ coil design. The successful performance test results of the prototype 100 kJ coil validated the design concept and fabrication technique of the 1 MJ coil. According to the achievement of the prototype 100 kJ UPS-SMES, the 1 MJ conduction-cooled LTS pulse coil has been fabricated successfully. The successful experimental results of the 100 kJ prototype coil with power converters and the fabrication procedure of the 1 MJ full size coil are described

Inter-application communication during LHD consecutive short pulse discharge experiment

LHD short pulse experiments are executed every three minutes. After the end of the discharge, the scientists must collect, analyze, visualize the last acquired data of the discharge, and prepare for the next discharge. From the beginning, the computer environment of the LHD (Large Helical Device) experiment has been built as a network distributed system, and various computers have been used for data acquisition or physical analysis. When one program is finished on one computer, that computer must send the results in order to the other computers to run programs. Smooth communication is required in order to finish all the tasks before the next discharge. To exchange the information among the applications running on the different computers, the authors have tried various methods, such as a commercial software to share the memory over the network, simple network file sharing method, IP multicast, web interfaces, and others. The purpose of this paper is to share our experiences of trial and error to build the network distributed systems for the consecutive plasma discharge experiments