Surface modification method for reactor incore structural component

International Nuclear Information System (INIS)

Obata, Minoru; Sudo, Akira.

1996-01-01

A large number of metal or ceramic small spheres accelerated by pressurized air are collided against a surface of a reactor incore structures or a welded surface of the structural components, and then finishing is applied by polishing to form compression stresses on the surface. This can change residual stresses into compressive stress without increasing the strength of the surface. Accordingly, stress corrosion crackings of the incore structural components or welded portions thereof can be prevented thereby enabling to extend the working life of equipments. (T.M.)

Mathematical optimization of incore nuclear fuel management decisions: Status and trends

International Nuclear Information System (INIS)

Turinsky, P.J.

1999-01-01

Nuclear fuel management involves making decisions about the number of fresh assemblies to purchase and their Attributes (e.g. enrichment and burnable poison loading), burnt fuel to reinsert, location of the assemblies in the core (i.e. loading pattern (LP)), and insertion of control rods as a function of cycle exposure (i.e. control rod pattern (CRP)). The out-of-core and incore nuclear fuel management problems denote an artificial separation of decisions to simplify the decisionmaking. The out-of-core problem involves multicycle analysis so that levelized fuel cycle cost can be evaluated; whereas, the incore problem normally involves single cycle analysis. Decision variables for the incore problem normally include all of the above noted decisions with the exception of the number of fresh assemblies, which is restricted by discharge burnup limits and therefore involves multicycle considerations. This paper reports on the progress that is being made in addressing the incore nuclear fuel management problem utilizing formal mathematical optimization methods. Advances in utilizing the Simulating Annealing, Genetic Algorithm and Tabu Search methods, with applications to pressurized and boiling water reactor incore optimization problem, will be reviewed. Recent work on the addition of multiobjective optimization capability to aide the decision maker, and utilization of heuristic rules and incorporation of parallel algorithms to increase computational efficiency, will be discussed. (orig.) [de

In-core LOCA (PTR) analysis with poisoned moderator

International Nuclear Information System (INIS)

Kim, S. R.; Kim, B. G.; Kim, T. M.; Choi, J. H.; Kim, Yun Ho; Choi, Hoon

2005-01-01

CANDU reactors have been analyzed and evaluated for the postulated in-core LOCA while the reactor is operating normally with low moderator poison concentration. However, when the reactor is operating with relatively large amounts of boron and/or gadolinium poisons in the moderator, the assessment for fuel integrity was required for pressure tube rupture (PTR) accident. The methodology of in-core LOCA analysis with poisoned moderator is developed to determine the effective trip parameters, evaluate the fuel integrity, and establish the standard reactor start-up model for CANDU reactor recently. The developed methodology and results are presented

Use of TRIGA flip fuel for improved in-core irradiations

Energy Technology Data Exchange (ETDEWEB)

Whittemore, W L [General Atomic Co., San Diego, CA (United States)

1974-07-01

Use of standard TRIGA fuel (20% enriched uranium) in a reactor provides a suitable facility for in-core irradiations. However, large numbers of in-core samples irradiated for long periods (many months) can be handled more economically with a TRIGA loaded with FLIP fuel. As an example, ten or more in-core thermionic devices (each worth 50 to 80 cents with respect to a water-filled position) were irradiated in the Mark III TRIGA at General Atomic Company for 18 months with only a modest change in excess reactivity due to core burnup. A core loading of FLIP fuel has been added to the General Atomic Mark F reactor in order to provide numerous in-core irradiation sites for the production of radioisotopes. Since the worth of a 500-gram sample of a molybdenum compound (used for the production of {sup 99}Mo) is about 25 to 50 cents with respect to a water-filled position, use of a FLIP- TRIGA core will permit the irradiation of more than 5 kilograms of a molybdenum compound. A procedure is under development for the production of {sup 99}Mo with relatively high specific activity. Several techniques to concentrate {sup 99}Mo have been tested experimentally. The results will be reported. (author)

Design and fabrication of self-powered in-core neutron flux monitor assembly

International Nuclear Information System (INIS)

Chung, M.K.; Cho, S.W.; Kang, H.D.; Cho, K.K.; Cho, B.S.; Kang, S.S.

1980-01-01

This is the final report on the prototypical fabrication of an in-core neutron flux monitor detector assembly for a specific power reactor conducted by KAERI from July 1, 1978 to December 31, 1979. It is well known that power reactors require a large number of in-core neutron flux detector for reactor regulation and the structures of detector assemblies are different from reactor to reactor. Therefore, from the nature of this project, it should be noted here that the target model of the prototypical farbrication of an in-core neutron flux monitor detector assembly is a VFD-2 System for Wolsung CANDU. It is concluded that fabrication of in-core neutron flux monitor detector assembly for CANDU reactor is technically feasible and will bring economical benefit as much as 50 % of the unit price if they are fabricated in Korea by using partially materials which are available from local market. (author)

The neutron beam intensity increase by in-core fuel management enhancement in multipurpose research reactors

International Nuclear Information System (INIS)

Martinc, R.; Vukadin, Z.; Konstantinovic, J.

1986-01-01

The exploitation characteristics of an existing multipurpose research reactor can be increased not only by great reconstruction, but also, to the considerable extent, by the in-core fuel management sophistication. The optimisation of the in-core fuel management procedure in such reactors is governed (among others) by the identified reactor utilisation goals, i.e. by weighting factors dedicated to different utilisation goals, which are often (regarding the in-core fuel management procedure) highly controversial. In this work the best solution for in-core fuel management is sought, with the highest weighting factor dedicated to the neutron beam usage, rather than sample irradiation in the reactor core. The term in-core fuel management includes: the core configuration, the locations of the fresh fuel inflow zone and spent fuel excite zone, and the fuel transfers between these two zones (author)

Comment on the in-core measurement in the WWER nuclear power plant

International Nuclear Information System (INIS)

Krett, V.; Dach, K.; Erben, O.

1985-01-01

The activity of the Nuclear Research Institute (NRI) Rez in the field of in-core measurement sensors is described in the paper. The results of comparison and calibration experiments realized on the WWR-S research reactor at the NRI are presented. Measurements with fission calorimeters and SPN detectors carried out in the framework of diagnostic fuel assembly program of WWER NPP reactors are described. Noise measurements with detectors of in-core instrumentation of diagnostic fuel assemblies are also mentioned. Comparison experiments on the WWER-440 NPP reactor are described and the method of function verification of neutron sensors of the in-core control system of these reactors is given. (author)

The in-core experimental program at the MIT Research Reactor

Energy Technology Data Exchange (ETDEWEB)

Kohse, G.E.; Hu, L-W., E-mail: kohse@mit.edu [Massachusetts Inst. of Technology, Nuclear Reactor Lab., Cambridge, Massachusetts (United States)

2014-07-01

This paper describes the program of in-core experiments at the Massachusetts Institute of Technology Research Reactor (MITR), a 6 MW research reactor. The MITR has a neutron flux and spectrum similar to those in water-cooled power reactors and therefore provides a useful test environment for materials and fuels research. In-core facilities include: a water loop operating at pressurized water or boiling water reactor conditions, an inert gas irradiation facility operating at temperature up to 850 {sup o}C and special purpose facilities including fuel irradiation experiments. Recent and ongoing tests include: water loop investigations of corrosion and thermal and mechanical property evolution of SiC/SiC composites for fuel cladding, irradiation of advanced materials and in-core sensors at elevated temperatures, irradiation in molten fluoride salt at 700 {sup o}C of metal alloy, graphite and composite materials for power reactor applications and instrumented irradiations of metal-bonded hydride fuel. (author)

In-core assembly configuration having a dual-wall pressure boundary for nuclear reactor

International Nuclear Information System (INIS)

Todt, W.H. Sr.; Playfoot, K.C.

1988-01-01

This patent describes an in-core detector assembly of the type having an in-core part and an out-of-core part and having an elongated outer hollow housing tube with a wall thickness, an inner hollow calibration tube with a wall thickness and disposed concentrically within the outer tube to define an annular space therewith, and a plurality of discrete, circular, rod-like elements extending through the annular space, the improvement comprising: the elements having outer diameters and being of a number to substantially occupy the entire annular space of both the incore and out-of-core parts without significant voids between elements; each of the elements including at least an outer sheath and interior highly compacted mineral insulation for the entire length of the element; a first number of the elements also including center lead means connected to condition responsive element means in the in-core part of the length of the assembly and a second, remaining number of the elements being non-operating elements. The wall thickness of the housing tube and the wall thickness of the calibration tube, taken together with the diameter of the elements, provide a thickness dimension adequate to meet code primary pressure requirements for normal nuclear reactor in-core conditions, while the wall thickness of the calibration tube alone provides a thickness dimension less than adequate to meet such requirements

Determination of fuel assembly vibrational modes through analysis of incore detector noise

International Nuclear Information System (INIS)

Johnson, R.S.

1986-01-01

In order to better characterize fuel assembly vibration at Duke Power Company's Oconee Nuclear Station, incore noise data were acquired an analyzed from prompt responding detectors incorporated in the Oconee 2, Cycle 7 core. Duke Power Company began actively pursuing an inhouse Neutron Noise Analysis program for routine surveillance of reactor internals vibration in 1979. Noise data has since been acquired and analyzed for twelve cycles of operation for the three Oconee units. Duke Power's Oconee Unit 2 is a Babcock and Wilcoxs pressurized water reactor with a rate thermal power of 2568MW. For Oconee 2, Cycle 7 operation, two test assemblies, each employing a string of seven axially-spaced, prompt responding hafnium detectors, were included in the final core design. Incore detector noise data were obtained during Cycle 7 at approximately 281 and 430 effective full power days (EFPD). In addition to the incore test detector signals, noise signals from the upper and lower chambers of the four excore power range detectors were recorded to aid in the analysis. The comparison of RMS signal levels for each incore detector and the phase relationships between detector locations within two test assemblies identified the first four fuel assembly bending modes associated with fixed end conditions

Hipertrofia ventricular izquierda como factor de riesgo cardiovascular en el paciente hipertenso

Directory of Open Access Journals (Sweden)

Llancaqueo V. Marcelo, Dr.

2012-11-01

Full Text Available La hipertrofia ventricular izquierda es una respuesta maladaptativa a la sobrecarga de presión crónica y un factor de riesgo importante para la fibrilación auricular, insuficiencia cardíaca diastólica, insuficiencia cardíaca sistólica, y la muerte súbita en pacientes con hipertensión. Dado que no todos los pacientes con hipertensión desarrollan hipertrofia ventricular izquierda, hay hallazgos clínicos que se deben tener en cuenta que puede alertar al médico sobre la presencia de hipertrofia ventricular izquierda por lo que una evaluación más definitiva se puede realizar utilizando un electrocardiograma, ecocardiograma o la resonancia magnética cardiovascular. Control de la presión arterial, la restricción de sodio, y la pérdida de peso de forma independiente facilitar la regresión de la hipertrofia ventricular izquierda. Elección de un fármaco antihipertensivo puede ser importante cuando se trata a un paciente con hipertrofia ventricular izquierda hipertensiva. Los inhibidores de la enzima convertidora o bloqueadores del receptor de angiotensina II, seguido por los antagonistas de los canales de calcio, facilitan más rápidamente la regresión de la hipertrofia ventricular izquierda. Con la regresión de la hipertrofia ventricular izquierda, la función diastólica y la reserva de flujo coronario generalmente mejoran, y disminuye el riesgo cardiovascular.

Improved sealing for in-core systems

International Nuclear Information System (INIS)

Dunford, S.

1989-01-01

The in-core instrumentation sealing nozzles designed by Framatome have three mechanical seals in series instead of the one traditional seal, and are pressurized by simply tightening up the nozzle covers. They have been installed from the start on all Framatome PWRs, as well as having been backfitted on Belgium and Yugoslavian units and chosen for the Chinese Qinshan plant. (author)

Feasibility study for CPR1000 incore measurement instrumentation educed from the reactor pressure vessel upper head

International Nuclear Information System (INIS)

Guang Jianwei; Liu Qian; Li Wenhong; Duan Yuangang

2010-01-01

The article discusses about the feasibility of in-core measurement instrumentation educed from the reactor pressure vessel (RPV) upper head. Incore instrumentation educed from the reactor pressure vessel upper head is one of advanced technology in the third generation nuclear power plant. This technology can reduce the manufacture problem of RPV; decrease the manufacture time effectively. Furthermore, this technology can get rid of the trouble for loss of water caused by many penetrations in the RPV bottom head, can increase security of nuclear power plant. By the description of structure analysis, comparison, maturity for four type incore instrumentation detectors, the incore instrumentation can be educed from RPV upper head, which can increase reactor's security, reduce the manufacture time, decrease group dose in refueling period. The core design ability can be enhanced through this study. (authors)

In-core fuel management programs for nuclear power reactors

International Nuclear Information System (INIS)

1984-10-01

In response to the interest shown by Member States, the IAEA organized a co-ordinated research programme to develop and make available in the open domain a set of programs to perform in-core fuel management calculations. This report summarizes the work performed in the context of the CRP. As a result of this programme, complete in-core fuel management packages for three types of reactors, namely PWR's, BWR's and PHWR are now available from the NEA Data Bank. For some reactor types, these program packages are available with three levels of sophistication ranging from simple methods for educational purposes to more comprehensive methods that can be used for reactor design and operation. In addition some operating data have been compiled to allow code validation. (author)

77 FR 30435 - In-core Thermocouples at Different Elevations and Radial Positions in Reactor Core

Science.gov (United States)

2012-05-23

... NUCLEAR REGULATORY COMMISSION 10 CFR Part 50 [Docket No. PRM-50-105; NRC-2012-0056] In-core Thermocouples at Different Elevations and Radial Positions in Reactor Core AGENCY: Nuclear Regulatory Commission... of operating licenses for nuclear power plants (``NPP'') to operate NPPs with in-core thermocouples...

The method to Certify Performance of Long-Lived In-Core Instrumentation

Energy Technology Data Exchange (ETDEWEB)

Roh, Kyung-ho; Cha, Kyoon-ho; Moon, Sang-rae [KHNP CRI, Daejeon (Korea, Republic of)

2015-10-15

Rh ICI (In-Core Instrumentation) used in OPR1000 generates the relatively large signal but its lifetime is below 6 years. Rh ICI consists of 5 detectors which is a type of SPND (Self Powered Neutron Detector), a couple of thermo-couple, one background wire and several fillers. The short lifetime of Rh detector causes increase of procurement price and space shortage of spent fuel pool. Also, it makes operators be exposed by more radiations. KHNP (Korea Hydro and Nuclear Power Co., Ltd.) CRI (Central Research Institute) is developing the LLICI (Long-Lived In-Core Instrumentation) based on vanadium to solve these problems. LLICI is the detector which is a type of SPND based on Vanadium and has the lifetime of about 10 years. The short lifetime of OPR1000's Rh ICI and long cycle operation strategy cause increase of procurement price, space shortage of spent fuel pool and more radiation exposed to operators. KHNP (Korea Hydro and Nuclear Power Co., Ltd.) CRI (Central Research Institute) is developing the LLICI (Long-Lived In-Core Instrumentation) to solve these problems.

Development of three methods for control rod position monitoring based on fixed in-core neutron detectors

International Nuclear Information System (INIS)

Peng, Xingjie; Li, Qing; Wang, Kan

2015-01-01

Highlights: • Three methods are utilized separately to unfold the control rod position from the fixed in-core neutron detector measurements. • Fixed in-core neutron detector measurements are simulated by neutronics code SMART. • Numerical results show that all these methods can unfold the control rod position accurately. • Two correction strategies are proposed to correct the simulated fixed in-core detector signals. - Abstract: Nuclear reactor core power distribution on-line monitoring system is very important in core surveillance, and this system should have the ability to indicate some abnormal conditions, such as the unacceptable control rod misalignment. In this study, the methodologies of radial basis function neural network (RBFNN), group method of data handling (GMDH) and Levenberg–Marquardt (LM) algorithm are utilized separately to unfold the control rod position from the fixed in-core neutron detector measurements. For using these methods, a large number of in-core detector signals corresponding to various known rod positions are needed. These data can be generated by an advanced core calculation code. In this study, the neutronics code SMART was used. The simulation results show that all these methods can unfold the control rod position accurately, and the performance comparison shows that the regularized RBFNN performs best. Two correction strategies are proposed to correct the simulated fixed in-core detector signals and improve the rod position monitoring accuracy when there are mismatches between actual physical factors and modeled physical factors

In-core fuel management practice in HANARO

International Nuclear Information System (INIS)

Kim Hark Rho; Lee Choong Sung; Lee Jo Bok

1997-01-01

KAERI (KOREA Atomic Energy Research Institute) completed the system performance tests for the HANARO (Hi-flux Advanced Neutron Application Research Reactor) on December 1994. Its initial criticality was achieved on February 8, 1995. A variety of the reactor physics experiments were performed in parallel with configuring the first cycle core and now HANARO is in the third cycle operation. The in-core fuel management in HANARO is performed on the following strategy: 1) the cycle length of the equilibrium core is at least 4 week FPDs, 2) the maximum linear heat generation rate should be within the design limit, 3) the reactor should have shutdown margin of 1% Δk/k at minimum, 4) the available thermal flux should satisfy the users' requirements. This paper presents the fuel management practice in HANARO. Section II briefly describes the design feature of the HANARO and the method of analysis follows in section III and section IV describes In-core fuel management practice and the conclusion is remarked in the final section. (author)

Logic based feature detection on incore neutron spectra

Energy Technology Data Exchange (ETDEWEB)

Racz, A.; Kiss, S.; Bende-Farkas, S. (Hungarian Academy of Sciences, Budapest (Hungary). Central Research Inst. for Physics)

1993-04-01

A general framework for detecting features of incore neutron spectra with a rule-based methodology is presented. As an example, we determine the meaningful peaks in the APSD-s. This work is part of a larger project, aimed at developing a noise diagnostic expert system. (Author).

Comparison study on in-core neutron detector for online neutron flux mapping of research and power reactor

International Nuclear Information System (INIS)

Zareen Khan Abdul Jalil Khan; Mohd Idris Taib; Izhar Abu Husin; Nurfarhana Ayuni

2010-01-01

This paper presents the comparison study on In-Core neutron detector using for online flux mapping of Research and Power reactor. Technical description of in-core neutron also taken into consideration to identify the different characterization of neutron detector and describe on Self Power neutron detector (SPND) for online neutron flux mapping. Able to provide information on the neutron flux distribution and understand how in-core neutron detector are being used in nuclear power plant including to enable to state the principles of neutron detector. (author)

In-core fuel management code package validation for BWRs

International Nuclear Information System (INIS)

1995-12-01

The main goal of the present CRP (Coordinated Research Programme) was to develop benchmarks which are appropriate to check and improve the fuel management computer code packages and their procedures. Therefore, benchmark specifications were established which included a set of realistic data for running in-core fuel management codes. Secondly, the results of measurements and/or operating data were also provided to verify and compare with these parameters as calculated by the in-core fuel management codes or code packages. For the BWR it was established that the Mexican Laguna Verde 1 BWR would serve as the model for providing data on the benchmark specifications. It was decided to provide results for the first 2 cycles of Unit 1 of the Laguna Verde reactor. The analyses of the above benchmarks are performed in two stages. In the first stage, the lattice parameters are generated as a function of burnup at different voids and with and without control rod. These lattice parameters form the input for 3-dimensional diffusion theory codes for over-all reactor analysis. The lattice calculations were performed using different methods, such as, Monte Carlo, 2-D integral transport theory methods. Supercell Model and transport-diffusion model with proper correction for burnable absorber. Thus the variety of results should provide adequate information for any institute or organization to develop competence to analyze In-core fuel management codes. 15 refs, figs and tabs

SEDRIO/INCORE, an automatic optimal loading pattern search system for PWR NPP reload core using an expert system

International Nuclear Information System (INIS)

Xian Chunyu; Zhang Zongyao

2003-01-01

The expert knowledge library for Daya Bay and Qinshan phase II NPP has been established based on expert knowledge, and the reload core loading pattern heuristic search is performed. The in-core fuel management code system INCORE that has been used in engineering design is employed for neutron calculation, and loading pattern is evaluated by using of cycle length and core radial power peaking factor. The developed system SEDRIO/INCORE has been applied in cycle 4 for unit 2 of Daya Bay NPP and cycle 4 for Phase II in Qinshan NPP. The application demonstrated that the loading patterns obtained by SEDRIO/INCORE system are much better than reference ones from the view of the radial power peak and the cycle length

About the study of irradiation effects on in-core instrumentation

International Nuclear Information System (INIS)

Angelino, G.

1972-01-01

The knowledge of in-core instrumentation performances is a very important item when irradiations of technological interest are concerned. When measurement of small changes in mechanical or thermal properties is of major importance, the effect of neutron and gamma irradiation on various transducers must be thoroughly evaluated. A rig mock-up was irradiated in the Triga Mark II Reactor of the Pavia University to assess the possibility of carrying out a study on irradiation effects on in-core instrumentation. Data on neutron flux distribution and γ-heating effect were collected from this preliminary experiment; at the same time a complete check was performed on rig assembling procedure, on the behaviour under operating conditions, and on the reactor loading and unloading operations. (author)

Arritmias ventriculares como manifestación de sarcoidosis cardiaca primaria

Directory of Open Access Journals (Sweden)

Jhan Altamar

2017-09-01

Full Text Available La afectación cardíaca en pacientes con sarcoidosis está siendo cada vez más reconocida y se asocia con mal pronóstico. Aunque en su patogénesis están implicados los factores ambientales y genéticos, la etiología de la sarcoidosis cardíaca no es clara. Las manifestaciones clínicas incluyen alteraciones de la conducción aurículo-ventricular, arritmias e insuficiencia cardíaca congestiva. Es una entidad extremadamente difícil de diagnosticar debido a que las manifestaciones clínicas son inespecíficas, y la sensibilidad y la especificidad de las modalidades de diagnóstico son limitadas. El tratamiento cardíaco óptimo no ha sido bien definido, y aunque los corticoides siguen siendo el pilar del manejo, hay poca evidencia de la dosis o la duración de la terapia. Se expone el caso de una paciente con sarcoidosis cardíaca aislada, que debutó con extrasístoles ventriculares y progresó a falla cardiaca y arritmias ventriculares sostenidas.

A Novel Method To On-Line Monitor Reactor Nuclear Power And In-Core Thermal Environments

International Nuclear Information System (INIS)

Liu, Hanying; Miller, Don W.; Li, Dongxu; Radcliff, Thomas D.

2002-01-01

For current nuclear power plants, nuclear power can not be directly measured and in-core fuel thermal environments can not be monitored due to the unavailability of an appropriate measurement technology and the inaccessibility of the fuel. If the nuclear deposited power and the in-core thermal conditions (i.e. fuel or coolant temperature and heat transfer coefficient) can be monitored in-situ, then it would play a valuable and critical role in increasing nuclear power, predicting abnormal reactor operation, improving core physical models and reducing core thermal margin so as to implement higher fuel burn-up. Furthermore, the management of core thermal margin and fuel operation may be easier during reactor operation, post-accident or spent fuel storage. On the other hand, for some advanced Generation IV reactors, the sealed and long-lived reactor core design challenges traditional measurement techniques while conventional ex-core detectors and current in-core detectors can not monitor details of the in-core fuel conditions. A method is introduced in this paper that responds to the challenge to measure nuclear power and to monitor the in-core thermal environments, for example, local fuel pin or coolant heat convection coefficient and temperature. In summary, the method, which has been designed for online in-core measurement and surveillance, will be beneficial to advanced plant safety, efficiency and economics by decreasing thermal margin or increasing nuclear power. The method was originally developed for a constant temperature power sensor (CTPS). The CTPS is undergoing design and development for an advanced reactor core to measure in-core nuclear power in measurement mode and to monitor thermal environments in compensation mode. The sensor dynamics was analyzed in compensation mode to determine the environmental temperature and the heat transfer coefficient. Previous research demonstrated that a first order dynamic model is not sufficient to simulate sensor

Remodelado ventricular y cirugía

Directory of Open Access Journals (Sweden)

Ignacio Moriones

2008-01-01

Se han diseñado anillos mitrales como el de Carpentier- McCarthy-Adams (IMR ETlogix™ para pacientes isquémicos, o el Edwards-Geoform™ en miocardiopatías. La asistencia ventricular puede conseguir en determinados casos recuperación permanente del volumen de la cavidad y función ventricular, particularmente en miocarditis y determinadas miocardiopatías. Paralelamente, se han iniciado experiencias con el sistema de contención CorCap o el sistema Myosplint. Finalmente, la actuación sobre las valvulopatías y la revascularización favorecen la restauración ventricular.

Studies on signal validation and sensor surveillance for in-core signals in NPP

International Nuclear Information System (INIS)

Ciftcioglu, O.

1991-12-01

Signal validation and sensor failure detection are two essential tasks to be carried out continuously in an operating reactor. Towards this aim, an optimal filtering approach for in-core NPP signals is implemented. The method concerns the specific measured input signal information as a parameter state and they are estimated by means of Kalman filtering technique. The signal validation and sensor surveillance system comprise filters as many as the states being considered and each filter receives all the measured signals as inputs in such a way that each filter in hand is desensitized to one of the individual input signals relative to others. In case of no failure of sensors all the filter outputs are identical. Each sensor output is tested by means of corresponding estimate present at the output of that filter which is desensitized to the sensor being tested. The comparison test is carried out continuously in real-time and any significant deviation noted during the test process is identified to be a sensor failure together with the faulty sensor. The method is investigated by means of real plant data of the in-core neutron detectors and core-inlet and outlet thermocouples of the Borssele nuclear power plant. The method has proven to be effective for fast and reliable in-core sensor failure detection as well as for in-core signal validation in normal operation indicating its further effectiveness for model validation applications in nuclear power plants. (author). 17 refs.; 4 figs.; 1 tab

Recent enhancements of the INSIGHT integrated in-core fuel management tool

International Nuclear Information System (INIS)

Akio, Yamamoto

2001-01-01

Recent enhancements of the INSIGHT system are described in this paper. The INSIGHT system is an integrated in-core fuel management tool for pressurized water reactors (PWRs) runs on UNIX workstations. The INSIGHT system provides various capabilities which contribute to reduce fuel cycle cost and workload of in-core fuel management tasks, i.e. core follow calculations, interactive loading pattern design, automated multicycle analysis and interface between detailed core calculation codes. To minimize engineers' workload, most of input data for analysis modules are automatically generated by the INSIGHT system through specification of calculation conditions in the graphic user interface. Recent enhancements of the INSIGHT system are mainly focused to improve efficiency of loading pattern optimization and flexibility of multicycle analyses. To increase optimization efficiency, a parallel calculation capability, various optimization theories, extension of heuristic rules, screening by neural networks and so on were incorporated in the loading pattern optimization module. The multicycle analyses module was rewritten to increase flexibility such as cycle dependent specification of loading pattern search methods and so on. The INSIGHT system is currently used by Japanese utilities not only for regular in-core fuel management tasks but also for strategic fuel management studies to reduce fuel cycle cost

Methods and techniques of nuclear in-core fuel management

International Nuclear Information System (INIS)

Jong, A.J. de.

1992-04-01

Review of methods of nuclear in-core fuel management (the minimal critical mass problem, minimal power peaking) and calculational techniques: reactorphysical calculations (point reactivity models, continuous refueling, empirical methods, depletion perturbation theory, nodal computer programs); optimization techniques (stochastic search, linear programming, heuristic parameter optimization). (orig./HP)

The verification of PWR-fuel code for PWR in-core fuel management

International Nuclear Information System (INIS)

Surian Pinem; Tagor M Sembiring; Tukiran

2015-01-01

In-core fuel management for PWR is not easy because of the number of fuel assemblies in the core as much as 192 assemblies so many possibilities for placement of the fuel in the core. Configuration of fuel assemblies in the core must be precise and accurate so that the reactor operates safely and economically. It is necessary for verification of PWR-FUEL code that will be used in-core fuel management for PWR. PWR-FUEL code based on neutron transport theory and solved with the approach of multi-dimensional nodal diffusion method many groups and diffusion finite difference method (FDM). The goal is to check whether the program works fine, especially for the design and in-core fuel management for PWR. Verification is done with equilibrium core search model at three conditions that boron free, 1000 ppm boron concentration and critical boron concentration. The result of the average burn up fuel assemblies distribution and power distribution at BOC and EOC showed a consistent trend where the fuel with high power at BOC will produce a high burn up in the EOC. On the core without boron is obtained a high multiplication factor because absence of boron in the core and the effect of fission products on the core around 3.8 %. Reactivity effect at 1000 ppm boron solution of BOC and EOC is 6.44 % and 1.703 % respectively. Distribution neutron flux and power density using NODAL and FDM methods have the same result. The results show that the verification PWR-FUEL code work properly, especially for core design and in-core fuel management for PWR. (author)

Vanadium Beta Emission Detectors for Reactor In-Core Neutron Monitoring

Energy Technology Data Exchange (ETDEWEB)

Andersson, I Oe; Soederlund, B

1969-06-15

In-core flux measurements are becoming increasingly important in both power reactors and test reactors. In particular power distribution measurements in large power reactors have to be performed with a great number of neutron detectors capable of withstanding high integrated flux values. This report presents a summary of the development and application of a new type of nuclear radiation sensor, a beta emission detector, for measurements at high neutron flux levels. The work has been carried out at the Section for Instrumentation and has been the basis for a type of neutron detector employed in the Marviken in-core system as well as for other types. The report describes the design and principle of operation, experiments and tests. Also included are the results and comments from a long-term irradiation of some detectors in the Halden reactor.

A new type of In-core sensor validation outline

International Nuclear Information System (INIS)

Figedy, S.

2006-01-01

In this a new type of in-core sensor validation method is outlined, which is based on combination of correlation coefficients and mutual information indices. First experience with this approach is described and further improvements to enhance the outcome reliability are proposed namely through computational intelligence techniques (Authors)

Computerized multiplexing and processing of in-core signals

International Nuclear Information System (INIS)

Meyer, J.

1982-09-01

After a presentation of the in-core instrumentation the main objectives of electric connection multiplexing are given. The conclusion of a study led to choose the multiplexing solution for the reactor building/electric building connections and to associate an information order management system based on the utilization of microprocessors. Finally, the control system (processors, organization, communication, language) is presented [fr

Qinshan NPP in-core fuel management improvement

International Nuclear Information System (INIS)

Kong Deping; Liao Zejun; Wu Xifeng; Wei Wenbin; Wang Yongming; Li Hua

2006-01-01

In the 10-year operation of Qinshan Nuclear Power Plant, the initial designed reloading strategy has been improved step by step based on the operation experiences and the advanced domestic and international fuel management methods. Higher burnup has been achieved and more economic operation gained through the loading pattern improvement and the fuel enrichment increased. The article introduces the in-core fuel management strategy improvement of Qinshan Nuclear Power Plant in its 10-year operation. (authors)

In-core fuel element temperature and flow measurment of HFETR

International Nuclear Information System (INIS)

Chen Daolong; Jiang Pei

1988-02-01

The HFETR in-core fuel element temperature-flow measurement facility and its measurement system are expounded. The applications of the instrumented fuel element to stationary and transient states measurements during the lift of power, the operation test of all lifetime at first load, and the deepening burn-up test at second load are described. The method of determination of the hot point temperature under the fin is discussed. The error analysis is made. The fuel element out-of-pile water deprivation test is described. The development of this measurement facility and succesful application have made important contribution to high power and deep burn-up safe operation at two load, in-core fuel element irradiation, and varied investigation of HFETR. After operation at two loads, the integrated power of this instrumented fuel element arrives at 90.88 MWd, its maximum point burn-up is about 64.9%, so that the economy of fuel use of HFETR is raised very much

Hipertrofia ventricular izquierda como factor de riesgo cardiovascular en el paciente hipertenso

OpenAIRE

Llancaqueo V. Marcelo, Dr.

2012-01-01

La hipertrofia ventricular izquierda es una respuesta maladaptativa a la sobrecarga de presión crónica y un factor de riesgo importante para la fibrilación auricular, insuficiencia cardíaca diastólica, insuficiencia cardíaca sistólica, y la muerte súbita en pacientes con hipertensión. Dado que no todos los pacientes con hipertensión desarrollan hipertrofia ventricular izquierda, hay hallazgos clínicos que se deben tener en cuenta que puede alertar al médico sobre la presencia de hipertrofia v...

Formulation of detector response function to calculate the power density profiles using in-core neutron detectors

International Nuclear Information System (INIS)

Ahmed, S. A.; Peter, J. K.; Semmler, W.; Shultis, J. K.

2007-01-01

By measuring neutron fluxes at different locations throughout a core, it's possible to derive the power-density profile P k (W cm - 3), at an axial depth z of fuel rod k. Micro-pocket fission detectors (MPFD) have been fabricated to perform such in-core neutron flux measurements. The purpose of this study is to develop a mathematical model to obtain axial power density distributions in the fuel rods from the in-core responses of the MPFDs

State-of-the-art incore detector system provides operational and safety benefits: Example, Hanford N Reactor

International Nuclear Information System (INIS)

Toffer, H.

1988-08-01

A presentation on the operational and safety benefits that can be derived from a state-of-the-art incore neutron monitoring system has been prepared for the DOE/ANL training course on ''The Potential Safety Impact of New and Emerging Technologies on the Operation of DOE Nuclear Facilities.'' Advanced incore neutron flux monitoring systems have been installed in some commercial reactors and should be considered for any new reactor designs or as backfits to existing plants. The recent installation of such a system at the Hanford N Reactor is used as an example in this presentation. Unfortunately, N Reactor has been placed in a cold standby condition and the full core incore system has not been tested under power conditions. Nevertheless, the evaluations that preceded the installation of the full core system provide interesting insight into the operational and safety benefits that could be expected

Special processor for in-core control systems

International Nuclear Information System (INIS)

Golovanov, M.N.; Duma, V.R.; Levin, G.L.; Mel'nikov, A.V.; Polikanin, A.V.; Filatov, V.P.

1978-01-01

The BUTs-20 special processor is discussed, designed to control the units of the in-core control equipment which are incorporated into the VECTOR communication channel, and to provide preliminary data processing prior to computer calculations. A set of instructions and flowsheet of the processor, organization of its communication with memories and other units of the system are given. The processor components: a control unit and an arithmetic logical unit are discussed. It is noted that the special processor permits more effective utilization of the computer time

Development of analytical code `ACCORD` for incore and plant dynamics of High Temperature Gas-cooled Reactor

Energy Technology Data Exchange (ETDEWEB)

Takeda, Takeshi; Tachibana, Yukio; Kunitomi, Kazuhiko [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Itakura, Hirofumi

1996-11-01

Safety demonstration test of the High Temperature Engineering Test Reactor will be carried out to demonstrate excellent safety features of a next generation High Temperature Gas-cooled Reactor (HTGR). Analytical code for incore and plant dynamics is necessary to assess the results of the safety demonstration test and to perform a design and safety analysis of the next generation HTGR. Existing analytical code for incore and plant dynamics of the HTGR can analyze behavior of plant system for only several thousand seconds after an event occurrence. Simulator on site can analyze only behavior of specific plant system. The `ACCORD` code has been, therefore, developed to analyze the incore and plant dynamics of the HTGR. The followings are the major characteristics of this code. (1) Plant system can be analyzed for over several thousand seconds after an event occurrence by modeling the heat capacity of the core. (2) Incore and plant dynamics of any plant system can be analyzed by rearranging packages which simulate plant system components one by one. (3) Thermal hydraulics for each component can be analyzed by separating heat transfer calculation for component from fluid flow calculation for helium and pressurized water systems. The validity of the `ACCORD` code including models for nuclear calculation, heat transfer and fluid flow calculation, control system and safety protection system, was confirmed through cross checks with other available codes. (author)

Development of analytical code 'ACCORD' for incore and plant dynamics of High Temperature Gas-cooled Reactor

International Nuclear Information System (INIS)

Takeda, Takeshi; Tachibana, Yukio; Kunitomi, Kazuhiko; Itakura, Hirofumi.

1996-11-01

Safety demonstration test of the High Temperature Engineering Test Reactor will be carried out to demonstrate excellent safety features of a next generation High Temperature Gas-cooled Reactor (HTGR). Analytical code for incore and plant dynamics is necessary to assess the results of the safety demonstration test and to perform a design and safety analysis of the next generation HTGR. Existing analytical code for incore and plant dynamics of the HTGR can analyze behavior of plant system for only several thousand seconds after an event occurrence. Simulator on site can analyze only behavior of specific plant system. The 'ACCORD' code has been, therefore, developed to analyze the incore and plant dynamics of the HTGR. The followings are the major characteristics of this code. (1) Plant system can be analyzed for over several thousand seconds after an event occurrence by modeling the heat capacity of the core. (2) Incore and plant dynamics of any plant system can be analyzed by rearranging packages which simulate plant system components one by one. (3) Thermal hydraulics for each component can be analyzed by separating heat transfer calculation for component from fluid flow calculation for helium and pressurized water systems. The validity of the 'ACCORD' code including models for nuclear calculation, heat transfer and fluid flow calculation, control system and safety protection system, was confirmed through cross checks with other available codes. (author)

Self-powered in-core neutron detector assembly with uniform perturbation characteristics

International Nuclear Information System (INIS)

1981-01-01

An in-core neutron detector assembly consisting of a number of longitudinally extending self-powered detectors is described. The uniform mechanical structures and materials are placed symmetrically at each active detector portion thus ensuring that local perturbation factors are uniform. (U.K.)

Traversing incore probe device

International Nuclear Information System (INIS)

Yoshioka, Michiko.

1985-01-01

Purpose: To measure the neutron flux distribution in the reactor core always at a high accuracy. Constitution: A nuclear fission ionizing chamber type detector is disposed at the end of a cable for sending a detection signal of a traversing incore probe device and, further, a gamma-ray ionizing chamber type detector is connected in adjacent therewith and a selection circuit for selecting both of the detection signals and inputting them to a display device is disposed. Then, compensation for the neutron monitors is conducted by the gamma-ray ionizing chamber type detector during normal operation in which control rods are not driven and the positioning is carried out by the nuclear fission ionizing chamber type detector. Furthermore, both of the compensation for the neutron detector and the positioning are carried out by the nuclear fission ionizing chamber type detector upon starting where the control rods are driven. (Sekiya, K.)

In-core fuel management via perturbation theory

International Nuclear Information System (INIS)

Mingle, J.O.

1975-01-01

A two-step procedure is developed for the optimization of in-core nuclear fuel management using perturbation theory to predict the effects of various core configurations. The first procedure is a cycle cost minimization using linear programming with a zoned core and discrete burnup groups. The second program utilizes an individual fuel assembly shuffling sequence to minimize the maldistribution of power generation. This latter quantity is represented by a figure of merit or by an assembly power peaking factor. A pressurized water reactor example calculation is utilized. 24 references

Deposition of corrosion products in-core

International Nuclear Information System (INIS)

Burrill, K.A.

1994-11-01

Data on corrosion product deposits on fuel sheaths are presented for a variety of operating conditions and water chemistries: boiling and non-boiling water; surface heat flux; pH, dissolved hydrogen concentration. Corrosion product behaviour in-core may be interpreted in terms of the solubility of magnetite and how it changes with water chemistry and temperature. A hypothesis of the deposition and release mechanisms was proposed in the 1970s in which particles deposited onto the sheath and subsequently dissolved in the heated water while being irradiated. Some of the deposition data may be interpreted using a model of these mechanisms. (author). 5 refs., 6 tabs., 8 figs

Modular approach to LWR in-core fuel management

International Nuclear Information System (INIS)

Urli, N.; Pevec, D.; Coffou, E.; Petrovic, B.

1980-01-01

The most important methods in the LWR in-core fuel management are reviewed. A modular approach and optimization by use of infinite multiplication factor and power form-factor are favoured. A computer program for rotation of fuel assemblies at reloads has been developed which improves further fuel economy and reliability of nuclear power plants. The program has been tested on the PWR core and showed to decrease the power form-factors and flatten the radial power distribution. (author)

In-core fuel management for the course on operational physics of power reactors

International Nuclear Information System (INIS)

Levine, S.H.

1982-01-01

The heart of a nuclear power station is the reactor core producing power from the fissioning of uranium or plutonium fuel. Expertise in many different technical fields is required to provide fuel for continuous economical operation of a nuclear power plant. In general, these various technical disciplines can be dichotomized into ''Out-of-core'' and ''In-core'' fuel management. In-core fuel management is concerned, as the name implies, with the reactor core itself. It entails calculating the core reactivity, power distribution, and isotopic inventory for the first and subsequent cores of a nuclear power plant to maintain adequate safety margins and operating lifetime for each core. In addition, the selection of reloading schemes is made to minimize energy costs

Feasibility study of incore fission chamber application for neutron flux measurements on the NET blanket

International Nuclear Information System (INIS)

Bertalot, L.

1987-01-01

A feasibility study has been carried out on the use of in-core fission chambers as neutron diagnostic tools to perform neutron flux measurements on the blanket component of NET. The high neutron and gamma fluxes and the severe thermal-mechanical and magnetic conditions of the blanket structure have been taken into account in this analysis. Preliminary design criteria and specifications of an in-core detector are presented for NET application. A research and development programme is outlined which aims to obtain more information on the tecnological constraints arising from the severe conditions of the NET blanket

Self powered neutron detectors as in-core detectors for Sodium-cooled Fast Reactors

Energy Technology Data Exchange (ETDEWEB)

Verma, V., E-mail: vasudha.verma@physics.uu.se [Division of Applied Nuclear Physics, Uppsala University, Box 516, SE-75120 Uppsala (Sweden); CEA, DEN, DER, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St-Paul-lez-Durance (France); Barbot, L.; Filliatre, P. [CEA, DEN, DER, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St-Paul-lez-Durance (France); Hellesen, C. [Division of Applied Nuclear Physics, Uppsala University, Box 516, SE-75120 Uppsala (Sweden); Jammes, C. [CEA, DEN, DER, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St-Paul-lez-Durance (France); Svärd, S. Jacobsson [Division of Applied Nuclear Physics, Uppsala University, Box 516, SE-75120 Uppsala (Sweden)

2017-07-11

Neutron flux monitoring system forms an integral part of the design of a Generation IV sodium cooled fast reactor. Diverse possibilities of detector system installation must be studied for various locations in the reactor vessel in order to detect any perturbations in the core. Results from a previous paper indicated that it is possible to detect changes in neutron source distribution initiated by an inadvertent withdrawal of outer control rod with in-vessel fission chambers located azimuthally around the core. It is, however, not possible to follow inner control rod withdrawal and precisely know the location of the perturbation in the core. Hence the use of complimentary in-core detectors coupled with the peripheral fission chambers is proposed to enable robust core monitoring across the radial direction. In this paper, we assess the feasibility of using self-powered neutron detectors (SPNDs) as in-core detectors in fast reactors for detecting local changes in the power distribution when the reactor is operated at nominal power. We study the neutron and gamma contributions to the total output current of the detector modelled with Platinum as the emitter material. It is shown that this SPND placed in an SFR-like environment would give a sufficiently measurable prompt neutron induced current of the order of 600 nA/m. The corresponding induced current in the connecting cable is two orders of magnitude lower and can be neglected. This means that the SPND can follow in-core power fluctuations. This validates the operability of an SPND in an SFR-like environment. - Highlights: • Studied possibility of using SPNDs as in-core detectors in SFRs. • Study done to detect local power profile changes when reactor is at nominal power. • SPND with a Pt-emitter gives measurable prompt current of the order of 600 nA/m. • Dominant proportion of prompt response is maintained throughout the operation. • Detector signal gives dynamic information on the power fluctuations.

Fast measurements of the in-core coolant velocity in a BWR by neutron noise analysis

International Nuclear Information System (INIS)

Hagen, T.H.J.J. van der; Hoogenboom, J.E.

1988-01-01

A method to determine in-core coolant velocities from neutron noise within short time intervals has been developed. The accuracy of the method was determined by using a simulation set-up and by using signals of a twin self-powered neutron detector installed in the core of the Dodewaard BWR in the Netherlands. In-core coolant velocities can be estimated within 2.5 s with a standard deviation (due to statistics) less than 2.1%. The method is suitable for velocity monitoring as is shown by the application to a stepwise velocity change of the coolant in a model of a coolant channel of a BWR. The presented technique was applied to determine the variations of the coolant velocity in the Dodewaard core during normal operation and during pressure steps. Only minor variations of the coolant velocity were detected during normal reactor conditions. An increase of those variations with pressure lowering - indicating a lower thermal hydraulic stability - could be detected. A clear velocity response to pressure steps could be determined which was also reflected in the cross-spectrum of the velocity with the vessel pressure and with the in-core neutron flux. (author)

Fisics-Incor bovine pericardial bioprostheses: 15 year results.

Science.gov (United States)

Pomerantzeff, P M; Brandao, C M; Cauduro, P; Puig, L B; Grinberg, M; Tarasoutchi, F; Cardoso, L F; Lerner, A; Stolf, N A; Verginelli, G; Jatene, A D

1998-01-01

From March 1982 to December 1995, 2,607 Fisics-Incor bovine pericardial bioprostheses were implanted in 2,259 patients. Mean age was 47.2 +/- 17.5 years, and 55% were male. Rheumatic fever was present in 1,301 (45.7%) patients. One thousand and seventy-three aortic valve replacements, 1,085 mitral replacements, 27 tricuspid replacements, 195 mitral-aortic replacements, and 16 other combined valve replacements were carried out. Combined procedures were performed in 788 (32.9%) patients, the most frequent being tricuspid valve repair (9.2%) and coronary artery bypass grafting (7.7%). Hospital mortality was 8.6% (194 patients), 8.6% for the mitral group, 4.7% for the aortic group, and 12.8% for double-valve replacements. The linear rates for calcification, thromboembolism, rupture, leak and endocarditis were, respectively, 1.1%, 0.2%, 0.9%, 0.1% and 0.5% patient-year. The actuarial survival curve was 56.7 +/- 5.4% in 15 years. Survival free from endocarditis was 91.92%, survival free from thromboembolism was 95 +/- 1.7%, survival free from rupture was 43.7 +/- 9.8%, survival free from leak was 98.9 +/- 4.5%, and survival free from calcification was 48.8 +/- 7.9% in 15 years. In the late postoperative period, 1,614 (80.6%) patients were in New York Heart Association functional Class I. We conclude that the results with the Fisics-Incor bovine pericardial prostheses were satisfactory in our group of patients.

Logic based feature detection on incore neutron spectra

International Nuclear Information System (INIS)

Bende-Farkas, S.; Kiss, S.; Racz, A.

1992-09-01

A methodology is proposed to investigate neutron spectra in such a way which is similar to human thinking. The goal was to save experts from tedious, mechanical tasks of browsing a large amount of signals in order to recognize changes in the underlying mechanisms. The general framework for detecting features of incore neutron spectra with a rulebased methodology is presented. As an example, the meaningful peaks in the APSDs are determined. This method is a part of a wider project to develop a noise diagnostic expert system. (R.P.) 6 refs.; 6 figs.; 1 tab

Irradiation performance of 9--12 Cr ferritic/martensitic stainless steels and their potential for in-core application in LWRs

International Nuclear Information System (INIS)

Jones, R.H.; Gelles, D.S.

1993-08-01

Ferritic-martensitic stainless steels exhibit radiation stability and stress corrosion resistance that make them attractive replacement materials for austenitic stainless steels for in-core applications. Recent radiation studies have demonstrated that 9% Cr ferritic/martensitic stainless steel had less than a 30C shift in ductile-to-brittle transition temperature (DBTT) following irradiation at 365C to a dose of 14 dpa. These steels also exhibit very low swelling rates, a result of the microstructural stability of these alloys during radiation. The 9 to 12% Cr alloys to also exhibit excellent corrosion and stress corrosion resistance in out-of-core applications. Demonstration of the applicability of ferritic/martensitic stainless steels for in-core LWR application will require verification of the irradiation assisted stress corrosion cracking behavior, measurement of DBTT following irradiation at 288C, and corrosion rates measurements for in-core water chemistry

Advanced in-core monitoring system for high-power reactors

International Nuclear Information System (INIS)

Mitin, V.I.; Alekseev, A.N.; Golovanov, M.N.; Zorin, A.V.; Kalinushkin, A.E.; Kovel, A.I.; Milto, N.V.; Musikhin, A.M.; Tikhonova, N.V.; Filatov, V.P.

2006-01-01

This paper encompasses such section as objective, conception and engineering solution for construction of advanced in-core instrumentation system for high power reactor, including WWER-1000. The ICIS main task is known to be an on-line monitoring of power distribution and functionals independently of design programs to avoid a common cause error. This paper shows in what way the recovery of power distribution has been carried out using the signals from in-core neutron detectors or temperature sensors. On the basis of both measured and processed data, the signals of preventive and emergency protection on local parameters (linear power of the maximum intensive fuel rods, departure from nucleate boiling ratio peaking factor) have been automatically generated. The paper presents a detection technology and processing methods for signals from SPNDs and TCs, ICIS composition and structure, computer hardware, system and applied software. Structure, composition and the taken decisions allow combining class IE and class B and C tasks in accordance with international standards of separation and safety category realization. Nowadays, ICIS-M is a system that is capable to ensure: monitoring, safety, information display and diagnostics function, which allow securing actual increase of quality, reliability and safety in operation of nuclear fuel and power units. Meanwhile, it reduce negative influence of human factor on thermal technical reliability in the operational process (Authors)

Self powered neutron detectors as in-core detectors for Sodium-cooled Fast Reactors

Science.gov (United States)

Verma, V.; Barbot, L.; Filliatre, P.; Hellesen, C.; Jammes, C.; Svärd, S. Jacobsson

2017-07-01

Neutron flux monitoring system forms an integral part of the design of a Generation IV sodium cooled fast reactor. Diverse possibilities of detector system installation must be studied for various locations in the reactor vessel in order to detect any perturbations in the core. Results from a previous paper indicated that it is possible to detect changes in neutron source distribution initiated by an inadvertent withdrawal of outer control rod with in-vessel fission chambers located azimuthally around the core. It is, however, not possible to follow inner control rod withdrawal and precisely know the location of the perturbation in the core. Hence the use of complimentary in-core detectors coupled with the peripheral fission chambers is proposed to enable robust core monitoring across the radial direction. In this paper, we assess the feasibility of using self-powered neutron detectors (SPNDs) as in-core detectors in fast reactors for detecting local changes in the power distribution when the reactor is operated at nominal power. We study the neutron and gamma contributions to the total output current of the detector modelled with Platinum as the emitter material. It is shown that this SPND placed in an SFR-like environment would give a sufficiently measurable prompt neutron induced current of the order of 600 nA/m. The corresponding induced current in the connecting cable is two orders of magnitude lower and can be neglected. This means that the SPND can follow in-core power fluctuations. This validates the operability of an SPND in an SFR-like environment.

Efecto de la localización del electrodo ventricular derecho (tracto de salida vs. ápex sobre la sincronía ventricular mecánica, en pacientes sometidos a terapia de implante de marcapaso cardiaco Effect of right ventricular electrode location (outflow tract vs. apex on mechanical ventricular synchrony in patients that underwent pacemaker implant therapy

Directory of Open Access Journals (Sweden)

Oscar S Rincón

2008-12-01

Full Text Available Objetivo: evaluar a profundidad el efecto de la estimulación ventricular desde el tracto de salida del ventrículo derecho y el ápex, sobre la sincronía ventricular mecánica. Materiales y métodos: estudio analítico de cohorte, en el que se realizó ecocardiograma transtorácico pre y post implante de marcapaso a 20 pacientes (diez por cada grupo con indicación de marcapaso definitivo, con implante del electrodo en el tracto de salida del ventrículo derecho y el ápex, sin cardiopatía estructural, fracción de eyección > 50%; QRS y conducción aurículo-ventricular normal, con el fin de evaluar la asincronía ventricular mecánica (modo M y Doppler tisular y los parámetros de implante y programación del dispositivo. Análisis estadístico: los resultados se presentan como promedios, desviación estándar o porcentajes. Las variables continuas se compararon utilizando prueba Chi cuadrado y ANOVA. Se consideró como estadísticamente significativa una p Objective: to assess in depth the effect of ventricular stimulation from the right ventricular outflow tract and the apex on mechanical ventricular synchrony. Materials and Methods: cohort analytical study. 20 patients with indication of definitive pacemaker indication underwent transthoracic echocardiogram before and after pacemaker implant with electrode implantation in the right ventricular outflow tract and in the apex (10 patients in each group. There was no structural cardiopathy, ejection fraction was > 50%, QRS and AV conduction were normal. Mechanical ventricular asynchrony (M mode and tissue doppler and implant and device parameters were evaluated. Statistical Analysis: results are given as mean values, standard deviation or percentages. Continuous variables were compared using Chi-square test and ANOVA. A p <0.05 value was considered statistically significant. Results: in five patients (25% a pre-implant ventricular asynchrony was found; in seven (70% ventricular asynchrony

Characteristic statistic algorithm (CSA) for in-core loading pattern optimization

International Nuclear Information System (INIS)

Liu Zhihong; Hu Yongming; Shi Gong

2007-01-01

To solve the problem of PWR in-core loading pattern optimization, a more suitable global optimization algorithm, i.e., Characteristic statistic algorithm (CSA), is used. The searching process of this algorithm and how to apply it to this problem are presented. Loading pattern optimization code SCYCLE is developed. Two different problems on real PWR models are calculated and the results are compared with other algorithms. It is shown that SCYCLE has high efficiency and good global performance on this problem. (authors)

Feasibility Study of Silver as Emitter of In-core Neutron Detector

Energy Technology Data Exchange (ETDEWEB)

Kong, Chi Dong; Lee, Hyun Suk [UNIST, Ulsan (Korea, Republic of); Shin, Ho Cheol; Cha, Kyoon Ho [Korea Hydro and Nuclear Power Corporation, Daejeon (Korea, Republic of); Lee, Deok Jung [UNIST, Ulsan (Korea, Republic of)

2016-05-15

The rhodium SPND(rhodium self-powered neutron detectors) provides strong detector signals so that they can be easily detected, but there is an issue the rhodium emitter needs to be replaced frequently because of its fast depletion. As an alternative, the vanadium SPND was designed and evaluated by Lee et al., but it also has an issue the detector signal level is too low. In this work, another material, silver, was introduced as emitter material of in-core detectors because its neutron absorption cross section is bigger than that of vanadium and smaller than rhodium. The feasibility of silver was investigated in comparison with the rhodium and vanadium detectors. The SPND model was designed using a Monte Carlo code MCNP6 and ORIGEN-S in SCALE code package. A silver self-powered neutron detector (SPND) was introduced in this paper, and the feasibility of silver as an emitter material of in-core detectors was investigated. The comparisons with rhodium and vanadium emitters demonstrate that silver has 0.78 years longer lifetime than rhodium and 10 times stronger signal than vanadium. Since a cycle length is generally 1.5 years, silver can be used for three cycles whereas rhodium should be replaced after two cycles.

In-core fuel management: New challenges

International Nuclear Information System (INIS)

Kolmayer, A.; Vallee, A.; Mondot, J.

1992-01-01

Experience accumulated by pressurized water reactor (PWR) utilities allows them to improve their strategies in the use of eventual margins to core design limits. They are used for nuclear steam supply system (NSSS) power upgrading, to improve operating margins, or to adapt fuel management to specific objectives. As a result, in-core fuel management strategies have become very diverse: UO 2 or mixed-oxide loading, out-in or in-out fuel loading patterns, extended or annual cycle lengths with margins on design limits such as moderator temperature coefficients, boron concentrations, or peaking factors. Perspectives also appear concerning use of existing plutonium stocks or actinide incineration. Burnable poisons are most often needed to satisfactorily achieve these goals. Among them, gadolinia are now largely used, owing to their excellent performance. More than 24 Framatome first cores and reloads, representing more than 3000 gadolinia-bearing rods, have been irradiated since 1983

Fixed type incore measuring device

International Nuclear Information System (INIS)

Oda, Naotaka; Ito, Hitoshi; Maeda, Hiroyuki

1998-01-01

The present invention concerns a measuring device using gamma thermometers to be used in a BWR type reactor. An input switch is inserted to the vicinity of a detection signal input portion of a signal cable connecting GT with the detection signal input portion of a fixed type incore measuring device, and a loop resistance measuring means is disposed to the input switch on the side of the GT by way of a measurement switch. Upon measuring loop resistance, the GT measuring circuit is switched from the detection signal input portion to the loop resistance measuring means by a switching operation of the input switch and the measurement switch thereby enabling to confirm the value of the loop resistance. In addition, the lowering of the voltage in the loop resistance is compensated to confirm the accurate measurement values to be used thereby enabling to measure GT detection signals accurately. A diagnosing means for diagnosing the state of GT based on the results of the measurement for the loop resistance is disposed, and the results are reported to an operator. (N.H.)

Heat resistant/radiation resistant cable and incore structure test device for FBR type reactor

International Nuclear Information System (INIS)

Tanimoto, Hajime; Shiono, Takeo; Sato, Yoshimi; Ito, Kazumi; Sudo, Shigeaki; Saito, Shin-ichi; Mitsui, Hisayasu.

1995-01-01

A heat resistant/radiation resistant coaxial cable of the present invention comprises an insulation layer, an outer conductor and a protection cover in this order on an inner conductor, in which the insulation layer comprises thermoplastic polyimide. In the same manner, a heat resistant/radiation resistant power cable has an insulation layer comprising thermoplastic polyimide on a conductor, and is provided with a protection cover comprising braid of alamide fibers at the outer circumference of the insulation layer. An incore structure test device for an FBR type reactor comprises the heat resistant/radiation resistant coaxial cable and/or the power cable. The thermoplastic polyimide can be extrusion molded, and has excellent radiation resistant by the extrusion, as well as has high dielectric withstand voltage, good flexibility and electric characteristics at high temperature. The incore structure test device for the FBR type reactor of the present invention comprising such a cable has excellent reliability and durability. (T.M.)

Development and research of in-core transducers at IAE (Institute of Atomic Energy)

International Nuclear Information System (INIS)

Huang Yucai; Qian Shunfa; Jia Guozhen

1989-10-01

The development of in-core transducers at IAE (Institute of Atomic Energy) and their applications in in-pile fuel assembly test are mentioned. These transducers include mainly tubed tungsten-rhenium thermocouple assembly, displacement transducer of linear variable differential transformer, pressure transducer of membrane type, gamma thermometer, turbine flow meter, self-powered neutron detector etc

Refractory metal component technology for in-core sensor design

International Nuclear Information System (INIS)

Cannon, C.P.

1986-02-01

Within recent years, an increasing concern over reactor safety has prompted tests that characterize reactor core environments during transient conditions. Such tests include the Loss-of-Fluid-Tests (Idaho National Engineering Lab (INEL)), Severe Fuel Damage Tests (INEL), Core Debris Rubble Tests (Sandia National Laboratories (SNL)), and similar tests performed by foreign nations. The in-core sensors for these tests require refractory metal components to be compatible with electrical insulator materials as well as materials comprising highly corrosive service mediums. This paper presents the refractory metal technology utilized to provide basic sensor designs in the above mentioned reactor tests

Development of in-core measurements in the reactor KS-150

International Nuclear Information System (INIS)

Rana, S.B.

1977-01-01

Mapping of the neutron flux density distribution and of the neutron fluence distribution in the KS-150 reactor core was carried out using an in-core measuring system. The system allows the in-service monitoring of important operating properties of the reactor core and fuel elements and consists of a mapping fuel element assembly with built-in SPN detectors, of transmission paths and a computer facility. The measurement of the neutron flux, neutron fluence and temperature fields in the reactor core was carried out during the power start-up of the reactor using self-powered DPZ-1 detectors. The obtained data are given and the axial distribution of neutron flux is graphically represented for different values of burnup at the same configuration of regulating rods, as is the axial distribution of neutron fluence for different configurations of the regulating rods during operation, and the in-service neutron fluence distribution. The maximal fuel temperature of 500.2 degC was found at a distance of 291.2 cm from the upper boundary of the reactor core, at a neutron flux of 1.46x10 14 n/cm 2 s. In comparison with other methods, this method proved easy and quick, the results reliable, reactivity perturbance negligible and the fuel element cost increase a negligible 4%. Neutron flux mapping using in-core self-powered detectors will be performed on a wider scale. (J.P./J.O.)

Translator from the symbol coding language for the BUTs-20 processor of the in-core reactor control system

International Nuclear Information System (INIS)

Vorob'ev, D.M.; Golovanov, M.N.; Levin, G.L.; Parfenova, T.K.; Filatov, V.P.

1978-01-01

A symbolic-language code translator is described; it has been developed for automation of making up programs for in-core control systems. The translator is written in the ASSEMBLER language which is included in the software of the M-6000 computer. Two scannings of the source program are required for making up the operating program in the internal language of the BUTs-2O processor. The flowsheet and listing of the interrogation program of an analog-to-digital converter are presented. It is emphasized that the translator proposed allows a time reduction for constructing programs for the in-core control systems by a factor of 10-15 and an improvement of their quality

78 FR 56174 - In-Core Thermocouples at Different Elevations and Radial Positions in Reactor Core

Science.gov (United States)

2013-09-12

... 52 [Docket No. PRM-50-105; NRC-2012-0056] In-Core Thermocouples at Different Elevations and Radial Positions in Reactor Core AGENCY: Nuclear Regulatory Commission. ACTION: Petition for rulemaking; denial...-core thermocouples at different elevations and radial positions throughout the reactor core to enable...

In-core materials testing under LWR conditions in the Halden reactor

International Nuclear Information System (INIS)

Bennett, P.J.; Hauso, E.; Hoegberg, N.W.; Karlsen, T.M.; McGrath, M.A.

2002-01-01

The Halden boiling water reactor (HBWR) has been in operation since 1958. It is a test reactor with a maximum power of 18 MW and is cooled and moderated by boiling heavy water, with a normal operating temperature of 230 C and a pressure of 34 bar. In the past 15 years increasing emphasis has been placed on materials testing, both of in-core structural materials and fuel claddings. These tests require representative light water reactor (LWR) conditions, which are achieved by housing the test rigs in pressure flasks that are positioned in fuel channels in the reactor and connected to dedicated water loops, in which boiling water reactor (BWR) or pressurised water reactor (PWR) conditions are simulated. Understanding of the in-core behaviour of fuel or reactor materials can be greatly improved by on-line measurements during power operation. The Halden Project has performed in-pile measurements for a period of over 35 years, beginning with fuel temperature measurements using thermocouples and use of differential transformers for measurement of fuel pellet or cladding dimensional changes and internal rod pressure. Experience gained over this period has been applied to on-line instrumentation for use in materials tests. This paper gives details of the systems used at Halden for materials testing under LWR conditions. The techniques used to provide on-line data are described and illustrative results are presented. (authors)

In-core materials testing under LWR conditions in the Halden reactor

Energy Technology Data Exchange (ETDEWEB)

Bennett, P.J.; Hauso, E.; Hoegberg, N.W.; Karlsen, T.M.; McGrath, M.A. [OECD Halden Reactor Project (Norway)

2002-07-01

The Halden boiling water reactor (HBWR) has been in operation since 1958. It is a test reactor with a maximum power of 18 MW and is cooled and moderated by boiling heavy water, with a normal operating temperature of 230 C and a pressure of 34 bar. In the past 15 years increasing emphasis has been placed on materials testing, both of in-core structural materials and fuel claddings. These tests require representative light water reactor (LWR) conditions, which are achieved by housing the test rigs in pressure flasks that are positioned in fuel channels in the reactor and connected to dedicated water loops, in which boiling water reactor (BWR) or pressurised water reactor (PWR) conditions are simulated. Understanding of the in-core behaviour of fuel or reactor materials can be greatly improved by on-line measurements during power operation. The Halden Project has performed in-pile measurements for a period of over 35 years, beginning with fuel temperature measurements using thermocouples and use of differential transformers for measurement of fuel pellet or cladding dimensional changes and internal rod pressure. Experience gained over this period has been applied to on-line instrumentation for use in materials tests. This paper gives details of the systems used at Halden for materials testing under LWR conditions. The techniques used to provide on-line data are described and illustrative results are presented. (authors)

Self-powered in-core neutron detector assembly with uniform perturbation characteristics

International Nuclear Information System (INIS)

Todt, W.H.; Playfoot, K.C.

1979-01-01

Disclosed is a self-powered in-core neutron detector assembly in which a plurality of longitudinally extending self-powered detectors have neutron responsive active portions spaced along a longitudinal path. A low neutron absorptive extension extends from the active portions of the spaced active portions of the detectors in symmetrical longitudinal relationship with the spaced active detector portions of each succeeding detector. The detector extension terminates with the detector assembly to provide a uniform perturbation characteristic over the entire assembly length

On the problem of in-core fuel management in power reactors

International Nuclear Information System (INIS)

Marinkovic, N.; Matausek, M.V.

1985-01-01

Within the scope of in-core fuel management including refuelling schedule and reactivity control it is indispensable to define nuclear fuel worth, optimal depletion of the spent fuel assemblies as well as isotopic composition of the spent fuel. This paper shows the computed values of the mentioned parameters in case of different reactor types, PWR, WWER, HWR and BWR of 1000 MWe as well as the intensity of radiation of the spent fuel 3 and 1 years after fission.(author)

Refurbishment of Cirus in-core components

International Nuclear Information System (INIS)

Bhatnagar, A.; Sahu, A.K.; Rathore, K.K.; Subudhi, D.; Kharpate, A.V.; Tikku, A.C.

2006-01-01

Circus is a 40- MWt vertical tank type research reactor with natural uranium as fuel, demineralised light water as coolant, heavy water as moderator and graphite as reflector. The reactor was commissioned in the year 1960 and operated at an overage availability factor of over 70% till early nineties, when various systems, structures and components (SSCs) started showing signs of ageing. Detailed ageing studies were therefore carried out to assess the condition of various SSCs and refurbishing requirements were finalized towards extending the life of the reactor. In-core components, being non-replaceable generally, were critically examined to the extent possible. Detailed visual examination of a few reactor vessel (RV) tubes, made of aluminium, was carried out using micro video camera and in addition all the RV tubes were inspected using eddy current testing method. RV shell, also made of aluminium, was similarly visually inspected with micro video camera. To assess the effect of irradiation on the RV material, samples of similar tubes irradiated to comparable neutron fluence were tested. Towards assessment of fatigue life of RV expansion joint, made of aluminium, a finite element analysis using NISA computer code was performed. Theoretical assessment for stored Wigner energy in graphite reflector was carried out. Graphite block samples were also removed from the reactor and stored energy levels were measured to plan for any in-situ graphite annealing, if required. Visual inspection of approachable portions of steel and aluminium thermal shields was also carried out. These water-cooled thermal shields provided above and below the RV were hydro tested. The weld joint between coolant inlet pipe and top plate of upper aluminium shield showed minor leakage. A special metallic hollow plug was developed and remotely installed in the leaky pipe to isolate the leaky portion while maintaining the coolant flow in the pipe. Helium leak was found from flange joints located on

A higher order depletion perturbation theory with application to in-core fuel management optimization

International Nuclear Information System (INIS)

Kropaczek, D.J.; Turinsky, P.J.

1990-01-01

Perturbation techniques utilized in reactor analysis have recently been applied in the solution of the in-core nuclear fuel management optimization problem. The use of such methods is motivated by the need to evaluate many times over, the core physics characteristics of loading pattern solutions obtained through an optimization process, which is typically iterative. Perturbation theory provides an efficient alternative to the prohibitively expensive, repetitive solutions of the system few-group neutron diffusion equations required in solving the fuel placement problem. A primary concern in the use of such methods is the control of perturbation errors arising during the fuel shuffling process. First-order accurate models inevitably resort to undue restriction of fuel movement during the optimization process to control these errors. Higher order perturbation theory models have the potential to overcome such limitations, which may result in the identification of local versus global optima. An accurate, computationally efficient reactor physics model based on higher order perturbation theory and geared toward the needs of large-scale in-core fuel management optimization is presented in this paper

Nuclear Characteristics of SPNDs and Preliminary Calculation of Hybrid Fixed Incore Detector with Monte Carlo Code

International Nuclear Information System (INIS)

Koo, Bon Seung; Lee, Kyung Hoon; Song, Jae Seung; Park, Sang Yoon

2013-01-01

In this paper, the basic nuclear characteristics of major emitter materials were surveyed. In addition, preliminary calculations of Cobalt-Vanadium fixed incore detector were performed using the Monte Carlo code. Calculational results were cross-checked by KARMA. KARMA is a two-dimensional multigroup transport theory code developed by the KAERI and approved by Korean regularity agency to be employed as a nuclear design tool for a Korean commercial pressurizer water reactor. The nuclear characteristics of the major emitter materials were surveyed, and preliminary calculations of the hybrid fixed incore detector were performed with the MCNP code. The eigenvalue and pin-by-pin fission power distributions were calculated and showed good agreement with the KARMA calculation results. As future work, gamma power distributions as well as several types of XS of the emitter, insulator, and collector regions for a Co-V ICI assembly will be evaluated and compared

Results and interpretation of noise measurements using in-core self powered neutron detector strings at Unit 2 of the Paks Nuclear Power Plant

International Nuclear Information System (INIS)

Gloeckler, O.; Por, G.; Valko, J.

1986-11-01

In-core neutron noise and fuel assembly outlet temperature noise measurements were performed at Unit 2 of Paks Nuclear Power Plant. Characteristics of the reactor and the noise measuring equipment are briefly described. The in-core Rhodium emitter selfpowered neutron detector strings positioned axially above the other show high coherence and linear phase at low frequencies indicating a marked transport effect, not regularly measured in PWRs. The coherence between horizontally placed neutron detectors is small and the phase is zero. A transport effect of different nature is obtained between neutron detectors (in-core and ex-core) and fuel assembly outlet thermocouples. The observed characteristics depend on reactor and fuel assembly power in a way supporting interpretation in terms of coolant density and void content changes and power feedback effects. During routine analysis vibration of 1.1 Hz appeared as a strong peak in the power spectra. The control assembly that was responsible for the observed behaviour could be localized with high certainty. (author)

Understanding susceptibility of in-core components to irradiation-assisted stress corrosion cracking

International Nuclear Information System (INIS)

Chung, H.M.; Ruther, W.E.; Sanecki, J.E.; Kassner, T.F.

1991-03-01

As nuclear plants age and accumulated fluences of core structural components increase, susceptibility of the components to irradiation-assisted stress corrosion cracking (IASCC) is also expected to increase. Irradiation-induced sensitization, commonly associated with an IASCC failure, was investigated in this study to provide a better understanding of long-term structural integrity of safety-significant in-core components. Irradiation-induced sensitization of high- and commercial-purity Type 304 stainless steels irradiated in BWRs was analyzed. 7 refs., 8 figs

Application of AC servo motor on the in-core neutron flux instrumentation system

International Nuclear Information System (INIS)

Du Xiaoguang; Wang Mingtao

2010-01-01

The application of ac servo motor in the In-Core Neutron Flux Instrumentation System is described. The hardware component of ac servo motor control system is different from the dc motor control system. The effect of two control system on the instrumentation system is compared. The ac servo motor control system can improve the accuracy of the motion control, optimize the speed control and increase the reliability. (authors)

Measurement of two-phase flow variables in a BWR by analysis of in-core neutron detector noise signals

International Nuclear Information System (INIS)

Stekelenburg, A.J.C.; Hagen, T.H.J.J. van der

1996-01-01

In this paper, the state of the art of the measurement of two-phase flow variables in a boiling water reactor (BWR) by analysis of in-core neutron detector noise signals is given. It is concluded that the neutronic processes involved in neutron noise are quite well understood, but that little is known about the density fluctuations in two-phase flow which are the main cause of the neutron noise. For this reason, the neutron noise measurements, like the well known two-detector velocity measurements, are still difficult to interpret. By analyzing neutron noise measurements in a natural circulation cooled BWR, it is illustrated that, once a theory on the density fluctuations is developed, two-phase flow can be monitored with a single in-core detector. (author). 70 refs, 4 figs

Asistencia mecánica ventricular de corta duración (shock cardiogénico

Directory of Open Access Journals (Sweden)

Tomasa Centella Hernández

2009-04-01

Full Text Available Los dispositivos de asistencia ventricular de corta duración se utilizan en aquellos pacientes que sufren una disfunción ventricular potencialmente reversible. Cualquier causa de shock cardiogénico puede ser una indicación para la colocación de una asistencia ventricular, si bien los beneficios son mayores en aquellos de causa potencialmente reversible tales como miocarditis, sobredosis de fármacos, hipotermia o arritmias ventriculares malignas. son tres las principales indicaciones para la colocación de este tipo de asistencia: 1 fallo ventricular grave potencialmente reversible en el que se asegura soporte temporal hasta la recuperación o hasta la posible revascularización; 2 pacientes con gran área isquémica en riesgo, en los que se proporciona soporte temporal durante un procedimiento percutáneo o revascularización quirúrgica, y 3 terapéutica puente hacia una asistencia de duración prolongada o hacia el trasplante.

Factores de riesgo para disfunción sistólica ventricular izquierda en adultos de un programa de salud global

Directory of Open Access Journals (Sweden)

Yessica María Giraldo Castrillón

2017-01-01

Full Text Available Introducción: La falla cardiaca, es un síndrome clínico habitualmente progresivo que con frecuencia comienza como disfunción sistólica ventricular izquierda y culmina con manifestaciones clínicas diversas de fallo de bomba y bajo gasto cardiaco hasta la muerte. Objetivo: Caracterizar los factores de riesgo que están asociados al desarrollo de disfunción sistólica ventricular izquierda y falla cardiaca secundaria como parte del espectro del síndrome de falla cardiaca en la población de Barranquilla-Colombia. Materiales y Métodos: Se realizó un estudio descriptivo de corte transversal con fuente secundaria de un estudio de salud global en la ciudad de Barranquilla-Colombia, en el que se hizo análisis univariado y bivariado para describir factores de riesgo asociados a la disfunción sistólica ventricular izquierda. Resultados: Se obtuvieron las prevalencias de cuatro factores de riesgo asociados al desarrollo de disfunción sistólica ventricular izquierda: hipertensión arterial 29.7%, obesidad 26.5%, hiperglucemia 4.6%, hipercolesterolemia 8.2% en pacientes mayores de 40 años los cuales tienen mayor riesgo. Discusión: Este estudio buscó llamar la atención sobre la disfunción sistólica ventricular izquierda, como una condición de descripción relativamente reciente y de potencial impacto en la salud de las poblaciones y los recursos de los sistemas de salud. Conclusiones: La prevalencia de los factores de riesgo para este estado pre-clínico podría llegar a ser alta y estos pacientes ameritarían, según recomendación de cierta evidencia, tamización para disfunción sistólica ventricular izquierda, así como estudios adicionales son requeridos. Cómo citar este artículo: Giraldo YM, Muñoz F, Navarro E, Segura ÁM. Factores de riesgo para disfunción sistólica ventricular izquierda en adultos de un programa de salud global. Rev Cuid. 2017; 8(1: 1519-28. http://dx.doi.org/10.15649/cuidarte.v8i1.371

ETRR-2 in-core fuel management strategy

International Nuclear Information System (INIS)

Khalil, M.Y.; Amin, Esmat; Belal, M.G.

2005-01-01

The Egypt second research reactor has many irradiation channels, beam tubes and irradiation boxes, inside and outside the reactor core. The core reload configuration has great effect on the core performance and fluxes in the irradiation channels. This paper deals with the design and safety analysis that were performed for the determination of ETRR2 in-core fuel management strategy which fulfills neutronic design criteria, safety reactor operation, utility optimization and achieve the overall fuel management criteria. The core is divided into 8 zones, in order to obtain the minimum and adjacent fuel movement scheme that is recommended from the operational point of view. Then a search for the initial core using backward iteration, one get different initial cores, one initial core would assume the equilibrium core after 250 full power days of operation, while the other assumes equilibrium after 199 full power days, and shows a better performance of power peaking factor. (author)

APLICACIONES CLÍNICAS DE LAS TÉCNICAS NUCLEARES EN EL ESTUDIO DEL SINCRONISMO VENTRICULAR / Clinical applications of nuclear techniques in the study of ventricular synchronism

Directory of Open Access Journals (Sweden)

Amalia Peix González

2012-07-01

Full Text Available ResumenTécnicas incruentas como la ecocardiografía, la resonancia magnética nuclear y los estudios de Medicina Nuclear (ventriculografía radioisotópica y gammagrafía de perfusión miocárdica con tomografía de emisión de fotón único, proporcionan información indirecta sobre el sincronismo ventricular cuando se utilizan parámetros de contractilidad mecánica. El análisis de fase de Fourier es un instrumento útil para el empleo de técnicas nucleares con este propósito y se ha aplicado, tanto en la ventriculografía radioisotópica como en la gammagrafía de perfusión. En este trabajo se presenta una revisión en el tiempo de los fundamentos y aplicaciones clínicas de las técnicas nucleares en el estudio del sincronismo ventricular. En la actualidad es la gammagrafía SPECT-gatillada, dentro de las técnicas nucleares, la más utilizada, por la posibilidad que ofrece de evaluar perfusión, función y sincronismo intraventricular en el mismo examen. / AbstractNoninvasive techniques such as echocardiography, nuclear magnetic resonance imaging and nuclear medicine studies (radionuclide ventriculography and myocardial perfusion scintigraphy with single photon emission tomography, provide indirect information about ventricular synchronism when parameters of mechanical contractility are used. The Fourier phase analysis is a useful tool for the use of nuclear techniques for this purpose, and has been applied in both radionuclide ventriculography and perfusion scintigraphy. A review in time of the basics and clinical applications of nuclear techniques in the study of ventricular synchronism is presented in this article. Nowadays, the gated-SPECT scintigraphy is the most common among nuclear techniques because it allows assessing perfusion, function, and intraventricular synchronism in the same test.

Computer programs for the in-core fuel management of power reactors

International Nuclear Information System (INIS)

1981-08-01

This document gives a survey of the presently tested and used computer programs applicable to the in-core fuel management of light and heavy water moderated nuclear power reactors. Each computer program is described (provided that enough information was supplied) such that the nature of the physical problem solved and the basic mathematical or calculational approach are evident. In addition, further information regarding computer requirements, up-to-date applications and experiences and specific details concerning implementation, staff requirements, etc., are provided. Program procurement conditions, possible program implementation assistance and commercial conditions (where applicable) are given. (author)

Long-lived Hybrid Incore Detector for Core Monitoring and Protection

Energy Technology Data Exchange (ETDEWEB)

Cha, Kyoon Ho [KEPCO Research Institute, Daejeon (Korea, Republic of)

2010-10-15

The signal production mechanism in a rhodium (Rh) fixed in-core detector emitter relies primarily on the beta particles resulting from neutron absorptions in either of two Rh isotopes to produce an electric current. As the neutron transmutation process depletes the Rh isotopes, the signal output per unit neutron flux from an Rh detector emitter will decrease. A vanadium detector is primarily sensitive to neutrons, but with a somewhat slower reaction time as that of a Rh detector. The benefit of vanadium over rhodium is its low depletion rate, which is a factor of 7 times less than that of rhodium. Platinum detectors are very sensitive to gamma flux, but only mildly sensitive to neutron flux. Because the depletion rate of platinum is very small, it can be neglected. Generally, both gamma and neutron signals are proportional to the assembly power. The characteristics of a new detector are the long life time due to the low depletion of emitter materials and the capability of reactor protection as well as reactor monitoring. The new detector uses vanadium and platinum as the emitter materials to meet the long life time and reactor protection capability. Vanadium detector is used for reactor monitoring and platinum detector is used for reactor protection. To determine the number of emitter strings, a comparative study of the power peaking factor monitoring accuracy for various self-powered fixed in-core detector geometries was made, and the configuration of the optimal detector design was also established and verified. The design of a new detector consists of five-string vanadium detector elements, and three-string platinum detector elements. The detector assembly also contains a background wire for compensation of noise signal and a thermocouple for use in the post-accident monitoring system. This new hybrid detector can be used for both reactor Monitoring And reactor Protection (MAP)

In-core fuel management: Reloading techniques. Proceedings of a technical committee meeting and workshop held in Vienna, 19-21 October 1992

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-08-01

The purpose of the Technical Committee Meeting and Workshop on In-core Fuel Management - Reloading Techniques, convened by the IAEA in Vienna from 19 to 21 October 1992, was to provide an international forum to review and discuss in-core fuel management reloading techniques for light water reactors. A presentation of the history and status of reloading techniques was given by S.H. Levine, Pennsylvania State University, and papers on various computer code descriptions, methodologies and experiences of utilities and vendors for nuclear fuel reloading were presented and discussed. Optimization techniques for reloadings, expert system codes and the number of energy groups used in reloading calculations were discussed in more detail during a workshop session. Refs, figs and tabs.

Code of practice for in-core instrumentation for neutron fluence rate (flux) measurements in power reactors

International Nuclear Information System (INIS)

Anon.

1982-01-01

This standard applies to in-core (on-line) neutron detectors and instrumentation which is designed for safety, information or control purposes. It also applies to components in so far as these components are contained within the primary envelope of the reactor. The detector types usually used are dc ionization chambers and self-powered neutron detectors

Development of Eddy Current Technique for Reactor In-Core Flux Thimble Wear

International Nuclear Information System (INIS)

Park, S. S.; Jang, Y. Y.; Yim, C. Y.; Park, K. H.

1990-01-01

Since in-core flux thimble tube wear the due to flow-induced vibration could degrade the integrity of nuclear reactor, the effective detection and interpretation of the wear is important. In order to establish an inspection technique for thimble tubes, an eddy current experiment was performed to determine the optimum test frequency, defect sensitivity and evaluation accuracy. Eddy current probes were designed and fabricated with a theory. Specimens with artificial defects were fabricated using electro discharge machining method. The results from inspection technique developed and on-site inspection showed good applicability

Construction of In-core Structure Test Section in HENDEL, (1)

International Nuclear Information System (INIS)

Kunitomi, Kazuhiko; Inagaki, Yoshiyuki; Ioka, Ikuo; Kondoh, Yasuo; Nekoya, Shinichi; Miyamoto, Yoshiaki; Akisada, Toshihiro; Yamaguchi, Shigeru.

1988-01-01

An In-core Structure Test Section (T 2 ) in Helium Engineering Demonstration Loop (HENDEL) simulates a part of the core bottom structure with the same scale as that of a high temperature engineering test reactor (HTTR) designed in Japan Atomic Energy Research Institute. The design and construction of T 2 test section were started in March 1983, and completed in June 1986. The main objectives of the T 2 test section are to verify thermal-hydraulic performance and integrity of the core bottom structure. The report describes the general outline of T 2 test section, and experience gained from construction and preliminary test with regard to the simulated core bottom structure. (author)

324. Asistencia ventricular mecánica. Experiencia del centro del corazón, berlín (berlin heart institute, alemania

Directory of Open Access Journals (Sweden)

T. Chávez

2012-04-01

Conclusiones: Sistemas de asistencia ventricular ofrecen la posibilidad de auxiliar o reemplazar por completo un corazón dañado. La mortalidad como consecuencia de cardiomiopatías dilatadas agudas o falla cardíaca por infarto agudo de miocardio ha sido considerablemente reducida mediante la aplicación de estos sistemas de asistencia ventricular.

Construction and utilization of linear empirical core models for PWR in-core fuel management

International Nuclear Information System (INIS)

Okafor, K.C.

1988-01-01

An empirical core-model construction procedure for pressurized water reactor (PWR) in-core fuel management is developed that allows determining the optimal BOC k ∞ profiles in PWRs as a single linear-programming problem and thus facilitates the overall optimization process for in-core fuel management due to algorithmic simplification and reduction in computation time. The optimal profile is defined as one that maximizes cycle burnup. The model construction scheme treats the fuel-assembly power fractions, burnup, and leakage as state variables and BOC zone enrichments as control variables. The core model consists of linear correlations between the state and control variables that describe fuel-assembly behavior in time and space. These correlations are obtained through time-dependent two-dimensional core simulations. The core model incorporates the effects of composition changes in all the enrichment control zones on a given fuel assembly and is valid at all times during the cycle for a given range of control variables. No assumption is made on the geometry of the control zones. A scatter-composition distribution, as well as annular, can be considered for model construction. The application of the methodology to a typical PWR core indicates good agreement between the model and exact simulation results

The symbol coding language for the BUTs processor of in-core reactor control systems

International Nuclear Information System (INIS)

Vorob'ev, D.M.; Golovanov, M.N.; Levin, G.L.; Parfenova, T.K.; Filatov, V.P.

1978-01-01

A symbolic coding language is described; it has been developed for automation of making up programs for in-core control systems. The systems use the ideology of the CAMAC-VECTOR system and include the BUTs-20 processor. The symbolic coding language has been developed as a programming language of the ASSEMBLER type. Operators of instructions and pseudo-instructions, the rules of reading in the text of the source program, and operator record formats are considered

Presentación tardía de aneurisma ventricular post-infarto. Caracterización por múltiples modalidades de imagen

Directory of Open Access Journals (Sweden)

Julio Oscar Cabrera Rego

2011-10-01

Full Text Available El aneurisma ventricular verdadero a nivel de la pared posteroinferior es infrecuente. Se presenta el caso de un paciente con episodios de taquicardia ventricular sostenida como primera manifestación de aneurisma ventricular post-infarto diagnosticado por ecocardiografía transtorácica y tridimensional, coronariografía invasiva y tomografía computarizada multicortes. La situación se resolvió favorablemente con optimización del tratamiento médico e implantación de un desfibrilador automático.

INCA: method of analyzing in-core detector data in power reactors

International Nuclear Information System (INIS)

Ober, T.G.; Terney, W.B.; Marks, G.H.

1975-04-01

A method (INCA) is described by which signals from fixed in-core detectors are related to estimates of the three dimensional power distribution in an operating reactor core and to the maximum linear heat rate in the core. A description of the large library of data accompanying the method is provided. A detailed examination of the analytical verifications performed using the method is presented, and a summary of the uncertainty associated with the method is given. The uncertainty assigned to the maximum linear heat rate inferred by the method from operating reactor data is found to be 5.8 percent at a 95/95 confidence level. (U.S.)

In-core monitor housing replacement at Fukushima Daiichi Unit No.4

International Nuclear Information System (INIS)

Arai, Tomoyuki

1999-01-01

The in-core monitor (ICM) housing replacement of a Boiling Water Reactor (BWR) has been completed at Fukushima-Daiichi Unit No. 4 (1F4) of the Tokyo Electric Power Company (TEPCO) in Japan. Since cracking of the inside surface of an ICM housing was found in this unit, the ICM housing was replaced with one made of low-carbon stainless steel (SS) to improve Intergranular Stress Corrosion Cracking (IGSCC) resistance. This project is the first application of the replacement procedure for the ICM housing and employs various advanced technologies. The outline of the ICM housing replacement project and applied technologies are discussed in this paper. (author)

Recent results from the MIT in-core experiments on coolant chemistry

International Nuclear Information System (INIS)

Harling, O.K.; Kohse, G.E.; Cabello, E.C.; Bernard, J.A.

1993-01-01

This paper reports results from an ongoing series of in-core experiments that have been conducted at the 5-MW(thermal) MIT Research Reactor (MITR-II) for optimizing coolant chemistries in light water reactors. Four experiments are in progress, including a pressurized coolant chemistry loop (PCCL), a boiling coolant chemistry loop (BCCL), a facility for the study of irradiation-assisted stress-corrosion cracking, and one for the evaluation of in situ sensors for the monitoring of crack propagation in metal (SENSOR). The first two have now been fully operational for several years. The latter two are scheduled to begin regular operation later this year

Self-powered in-core detectors of cobalt type

International Nuclear Information System (INIS)

Jonsson, Georg

1975-01-01

Testing and development of self-powered neutron detectors with a cobalt emitter is described. Long term irradiation at 400 deg C is expected to indicate insulation quality, change in calibration and 60 Co build-up. Dynamic tests to investigate possible transient effects due to temperature changes are being performed on a number of detectors up to about 600 deg C. A long term irradiation at low temperature has been terminated after 4.5 years. On completion, neutron dose was estimated to be 5.6 x 10 21 nvt and the 60 Co background was 9.3 % of the full flux signal. A recently introduced long term test is expected to provide data on instability effects due to 61 Co. For a BWR in-core detector installation, the main advantage of cobalt detectors, apart from the small size, appears to be long life. Development work is being done on detectors with vanadium-cobalt emitters, electronic separation of fast and delayed signals and reduction of gamma sensitivity. (O.T.)

Swarm intelligence of artificial bees applied to In-Core Fuel Management Optimization

Energy Technology Data Exchange (ETDEWEB)

Santos de Oliveira, Iona Maghali, E-mail: ioliveira@con.ufrj.br [Nuclear Engineering Program, Federal University of Rio de Janeiro, P.O. Box 68509, Zip Code 21945-970, Rio de Janeiro, RJ (Brazil); Schirru, Roberto, E-mail: schirru@lmp.ufrj.br [Nuclear Engineering Program, Federal University of Rio de Janeiro, P.O. Box 68509, Zip Code 21945-970, Rio de Janeiro, RJ (Brazil)

2011-05-15

Research highlights: > We present Artificial Bee Colony with Random Keys (ABCRK) for In-Core Fuel Management Optimization. > Its performance is examined through the optimization of a Brazilian '2-loop' PWR. > Feasibility of using ABCRK is shown against some well known population-based algorithms. > Additional advantage includes the utilization of fewer control parameters. - Abstract: Artificial Bee Colony (ABC) algorithm is a relatively new member of swarm intelligence. ABC tries to simulate the intelligent behavior of real honey bees in food foraging and can be used for solving continuous optimization and multi-dimensional numeric problems. This paper introduces the Artificial Bee Colony with Random Keys (ABCRK), a modified ABC algorithm for solving combinatorial problems such as the In-Core Fuel Management Optimization (ICFMO). The ICFMO is a hard combinatorial optimization problem in Nuclear Engineering which during many years has been solved by expert knowledge. It aims at getting the best arrangement of fuel in the nuclear reactor core that leads to a maximization of the operating time. As a consequence, the operation cost decreases and money is saved. In this study, ABCRK is used for optimizing the ICFMO problem of a Brazilian '2-loop' Pressurized Water Reactor (PWR) Nuclear Power Plant (NPP) and the results obtained with the proposed algorithm are compared with those obtained by Genetic Algorithms (GA) and Particle Swarm Optimization (PSO). The results show that the performance of the ABCRK algorithm is better than or similar to that of other population-based algorithms, with the advantage of employing fewer control parameters.

Swarm intelligence of artificial bees applied to In-Core Fuel Management Optimization

International Nuclear Information System (INIS)

Santos de Oliveira, Iona Maghali; Schirru, Roberto

2011-01-01

Research highlights: → We present Artificial Bee Colony with Random Keys (ABCRK) for In-Core Fuel Management Optimization. → Its performance is examined through the optimization of a Brazilian '2-loop' PWR. → Feasibility of using ABCRK is shown against some well known population-based algorithms. → Additional advantage includes the utilization of fewer control parameters. - Abstract: Artificial Bee Colony (ABC) algorithm is a relatively new member of swarm intelligence. ABC tries to simulate the intelligent behavior of real honey bees in food foraging and can be used for solving continuous optimization and multi-dimensional numeric problems. This paper introduces the Artificial Bee Colony with Random Keys (ABCRK), a modified ABC algorithm for solving combinatorial problems such as the In-Core Fuel Management Optimization (ICFMO). The ICFMO is a hard combinatorial optimization problem in Nuclear Engineering which during many years has been solved by expert knowledge. It aims at getting the best arrangement of fuel in the nuclear reactor core that leads to a maximization of the operating time. As a consequence, the operation cost decreases and money is saved. In this study, ABCRK is used for optimizing the ICFMO problem of a Brazilian '2-loop' Pressurized Water Reactor (PWR) Nuclear Power Plant (NPP) and the results obtained with the proposed algorithm are compared with those obtained by Genetic Algorithms (GA) and Particle Swarm Optimization (PSO). The results show that the performance of the ABCRK algorithm is better than or similar to that of other population-based algorithms, with the advantage of employing fewer control parameters.

Surgical ablation of ventricular tachycardia secondary to congenital ventricular septal aneurysm.

Science.gov (United States)

Graffigna, A; Minzioni, G; Ressia, L; Vigano, M

1994-04-01

Three patients underwent surgical ablation for ventricular tachycardia resulting from an aneurysm of the membranous portion of the ventricular septum. Two patients had a definite history of cardiac murmur during infancy, and one of them was found at the time of operation to have a left-to-right shunt through the apex of the aneurysm. The earliest ventricular activation sites were located around the neck of the aneurysm and were ablated in 1 patient by encircling the endocardial ventriculotomy and by cryoablation in the remaining 2. After focus resection had been completed, aneurysm resection and ventricular septal reconstruction were performed. All patients were alive and free of ventricular tachycardia and did not need medication as of 61, 66, and 88 months postoperatively. Spontaneous closure of a ventricular septal defect may lead to the formation of an aneurysm in the ventricular septum that may sustain ventricular tachycardias. Such arrhythmias can be effectively treated using electrically guided surgical techniques.

Presentación tardía de aneurisma ventricular post-infarto. Caracterización por múltiples modalidades de imagen

Directory of Open Access Journals (Sweden)

Julio Oscar Cabrera Rego

2011-12-01

Full Text Available El aneurisma ventricular verdadero a nivel de la pared posteroinferior es infrecuente. Se presenta el caso de un paciente con episodios de taquicardia ventricular sostenida como primera manifestación de aneurisma ventricular post-infarto diagnosticado por ecocardiografía transtorácica y tridimensional, coronariografía invasiva y tomografía computarizada multicortes. La situación se resolvió favorablemente con optimización del tratamiento médico e implantación de un desfibrilador automático.Late Ventricular Post-myocardial Infarction Aneurysm. Characterization through Several Imaging TestsTrue ventricular aneurysm in the low posterior wall is uncommon. The case of a patient with sustained ventricular tachycardia as first symptom of a post-myocardial left ventricular aneurysm, finally diagnosed through transthoracic 2D and 3D-echocardiography, invasive coronary angiography and multislice computed tomography is presented. Medical treatment was optimized and an automatic implantable cardioverter defibrillator was used. Thus, the patient evolved favourably.

On-line extraction of the variance caused by burn-up in in-core three-dimensional power distribution

International Nuclear Information System (INIS)

Wang Yaqi; Luo Zhengpei; Li Fu; Liu Wenfeng

2001-01-01

In most of PWRs, the ex-core ion-chambers are the sole real-time sensors to respond to in-core power and its axial offset. However, the calibration coefficient of the ion-chambers depends on the (3D) power distribution and varies with the burn-up. People expect to know the variance in distribution caused by burn-up directly from the signals of ion-chambers. This expectation is not realized as yet, because an ion-chamber almost only responds to its nearest fuel assemblies. The authors then developed a two-step method for burn-up characteristic extraction: the harmonics synthesis method and harmonics' burn-up grouping. Using the extracted burn-up characteristics, the relationship between the readings of the ex-core ion-chambers and the in-core 3D power distribution is set up. Through the simulation on the heating reactor, the method of burn-up characteristic extraction is verified under engineering conditions. It is possible to on-line extract the variance caused by burn-up in 3D power distribution

A benefit assessment of using in-core neutron detector signals in core protection calculator system (CPCS)

International Nuclear Information System (INIS)

Han, S.; Park, S.J.; Seong, P.H.

1997-01-01

A Core Protection Calculator System (CPCS) is a digital computer based safety system generating trip signals based on the calculation of Departure from Nucleate Boiling Ratio (DNBR) and Local Power Density (LPD). Currently, CPCS uses ex-core detector signals for core power calculation and it has some uncertainties. In this study, in-core detector signals which directly measure inside flux of core are applied to CPCS to get more accurate power distribution profile, DNBR and LPD. In order to improve axial power distribution calculation, piece-wise cubic Spline method is applied; from the 40 nodes of expanded signals, more accurate and detailed core information can be provided. Simulation is carried out to verify its applicability to power distribution calculation. Simulation result shows that the improved method reduces the calculational uncertainties significantly and it allows larger operational margin. It is also expected that no power reduction is required while Core Operating Limit Supervisory System (COLSS) is out-of-service due to reduced uncertainties when the improved method is applied. In this study, a quantitative economic benefit assessment of using in-core neutron detector signals is also carried out. (authors)

A benefit assessment of using in-core neutron detector signals in core protection calculator system(CPCS)

International Nuclear Information System (INIS)

Han, Seung

1996-02-01

A Core Protection Calculator System(CPCS) is a digital computer based safety system generating trip signals based on the calculation of Departure from Nucleate Boiling Ratio(DNBR) and Local Power Density(LPD). Currently, CPCS uses ex-core detector signals for core power calculation and it has some uncertainties. In this study, In-core detector signals which directly measure inside flux of core are applied to CPCS to get more accurate power distribution profile, DNBR and LPD. In order to improve axial power distribution calculation, piecewise cubic spline method is applied: From the 40 nodes of expanded signals, more accurate and detailed core information can be provided. Simulation is carried out to verify its applicability to power distribution calculation. Simulation result shows that the improved method reduces the calculational uncertainties significantly and it allows larger operational margin. It is also expected that no power reduction is required while Core Operating Limit Supervisory System(COLSS) is out-of-service due to reduced uncertainties when the improved method is applied. In this study, a quantitative economic benefit assessment of using in-core neutron detector signals is also carried out

On Use of Multi-Chambered Fission Detectors for In-Core, Neutron Spectroscopy

Science.gov (United States)

Roberts, Jeremy A.

2018-01-01

Presented is a short, computational study on the potential use of multichambered fission detectors for in-core, neutron spectroscopy. Motivated by the development of very small fission chambers at CEA in France and at Kansas State University in the U.S., it was assumed in this preliminary analysis that devices can be made small enough to avoid flux perturbations and that uncertainties related to measurements can be ignored. It was hypothesized that a sufficient number of chambers with unique reactants can act as a real-time, foilactivation experiment. An unfolding scheme based on maximizing (Shannon) entropy was used to produce a flux spectrum from detector signals that requires no prior information. To test the method, integral, detector responses were generated for singleisotope detectors of various Th, U, Np, Pu, Am, and Cs isotopes using a simplified, pressurized-water reactor spectrum and fluxweighted, microscopic, fission cross sections, in the WIMS-69 multigroup format. An unfolded spectrum was found from subsets of these responses that had a maximum entropy while reproducing the responses considered and summing to one (that is, they were normalized). Several nuclide subsets were studied, and, as expected, the results indicate inclusion of more nuclides leads to better spectra but with diminishing improvements, with the best-case spectrum having an average, relative, group-wise error of approximately 51%. Furthermore, spectra found from minimum-norm and Tihkonov-regularization inversion were of lower quality than the maximum entropy solutions. Finally, the addition of thermal-neutron filters (here, Cd and Gd) provided substantial improvement over unshielded responses alone. The results, as a whole, suggest that in-core, neutron spectroscopy is at least marginally feasible.

Systolic left ventricular function according to left ventricular concentricity and dilatation in hypertensive patients

DEFF Research Database (Denmark)

Bang, Casper; Gerdts, Eva; Aurigemma, Gerard P

2013-01-01

Left ventricular hypertrophy [LVH, high left ventricular mass (LVM)] is traditionally classified as concentric or eccentric based on left ventricular relative wall thickness. We evaluated left ventricular systolic function in a new four-group LVH classification based on left ventricular dilatation...... [high left ventricular end-diastolic volume (EDV) index and concentricity (LVM/EDV)] in hypertensive patients....

Left ventricular function in patients with ventricular arrhythmias and aortic valve disease

International Nuclear Information System (INIS)

Santinga, J.T.; Kirsh, M.M.; Brady, T.J.; Thrall, J.; Pitt, B.

1983-01-01

Forty patients having aortic valve replacement were evaluated preoperatively for ventricular arrhythmia and left ventricular ejection fraction. Arrhythmias were classified as complex or simple using the Lown criteria on the 24-hour ambulatory electrocardiogram; ejection fractions were determined by radionuclide gated blood pool analysis and contrast angiography. The ejection fractions determined by radionuclide angiography were 59.1 +/- 13.1% for 26 patients with simple or no ventricular arrhythmias, and 43.9 +/- 20.3% for 14 patients with complex ventricular arrhythmias (p less than 0.01). Ejection fractions determined by angiography, available for 31 patients, were also lower in patients with complex ventricular arrhythmias (61.1 +/- 16.3% versus 51.4 +/- 13.4%; p less than 0.05). Seven of 9 patients showing conduction abnormalities on the electrocardiogram had complex ventricular arrhythmias. Eight of 20 patients with aortic stenosis had complex ventricular arrhythmias, while 2 of 13 patients with aortic insufficiency had such arrhythmias. It is concluded that decreased left ventricular ejection fraction, intraventricular conduction abnormalities, and aortic stenosis are associated with an increased frequency of complex ventricular arrhythmias in patients with aortic valve disease

Rest and exercise ventricular function in adults with congenital ventricular septal defects

International Nuclear Information System (INIS)

Jablonsky, G.; Hilton, J.D.; Liu, P.P.; Morch, J.E.; Druck, M.N.; Bar-Shlomo, B.Z.; McLaughlin, P.R.

1983-01-01

Rest and exercise right and left ventricular function were compared using equilibrium gated radionuclide angiography in 19 normal sedentary control subjects and 34 patients with hemodynamically documented congenital ventricular septal defect (VSD). Gated radionuclide angiography was performed at rest and during each level of graded supine bicycle exercise to fatigue. Heart rate, blood pressure, maximal work load achieved, and right and left ventricular ejection fractions were assessed. The control subjects demonstrated an increase in both the left and right ventricular ejection fractions with exercise. All study groups failed to demonstrate an increase in ejection fraction in either ventricle with exercise. Furthermore, resting left ventricular ejection fraction in Groups 2 and 3 was lower than that in the control subjects and resting right ventricular ejection fraction was lower in Group 3 versus control subjects. Thus left and right ventricular function on exercise were abnormal in patients with residual VSD as compared with control subjects; rest and exercise left ventricular ejection fractions remained abnormal despite surgical closure of VSD in the remote past; resting left and right ventricular function was abnormal in patients with Eisenmenger's complex; lifelong volume overload may be detrimental to myocardial function

Arrhythmogenic Right Ventricular Cardiomyopathy in an Endurance Athlete Presenting with Ventricular Tachycardia and Normal Right Ventricular Function.

Science.gov (United States)

Hedley, Jeffrey S; Al Mheid, Ibhar; Alikhani, Zoubin; Pernetz, Maria A; Kim, Jonathan H

2017-08-01

Arrhythmogenic right ventricular cardiomyopathy, a genetically inherited disease that results in fibrofatty replacement of normal cardiac myocytes, has been associated with sudden cardiac death in athletes. Long-term participation in endurance exercise hastens the development of both the arrhythmic and structural arrhythmogenic right ventricular cardiomyopathy phenotypes. We describe the unusual case of a 34-year-old, symptomatic, female endurance athlete who had arrhythmogenic right ventricular cardiomyopathy in the presence of a structurally normal right ventricle. Clinicians should be aware of this infrequent presentation when evaluating athletic patients who have ventricular arrhythmias and normal findings on cardiac imaging studies.

Prophylactic implantable defibrillator in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia and no prior ventricular fibrillation or sustained ventricular tachycardia.

LENUS (Irish Health Repository)

Corrado, Domenico

2010-09-21

The role of implantable cardioverter-defibrillator (ICD) in patients with arrhythmogenic right ventricular cardiomyopathy\\/dysplasia and no prior ventricular fibrillation (VF) or sustained ventricular tachycardia is an unsolved issue.

Test of In-core Flux Detectors in KNK II

CERN Document Server

Hoppe, P

1979-01-01

The development of in-core detectors for Liquid Metal Fast Breeder Reactors (LMFBRs) is still in an early stage, and little operation experience is available. Therefore self-powered neutron and gamma detectors and neutron sensitive ionization chambers -especially developed for LMFBRs- have been tested in the Fast Sodium Cooled Test Reactor KNK II. Seven flux detectors have been installed in the core of KNK II by means of a special test rig. Five of them failed already within the first week during operation in the reactor. Due to measurements of electrical resistances and capacities, sodium penetrating into the detectors or cables probably seems to be the cause. As tests prior to the installation in the core proved the tightness of all detectors, it is suspected that small cracks have developed in the detector casings or in the outer cable sheaths during their exposure to the hot coolant. Two ionization chambers did not show these faults. However, one of them failed because the saturation current plateau disap...

Analysis of an ultrasonic level device for in-core Pressurized Water Reactor coolant detection

International Nuclear Information System (INIS)

Johnson, K.R.

1981-01-01

A rigorous semi-empirical approach was undertaken to model the response of an ultrasonic level device (ULD) for application to in-core coolant detection in Pressurized Water Reactors (PWRs). An equation is derived for the torsional wave velocity v/sub t phi/ in the ULD. Existing data reduction techniques were analyzed and compared to results from use of the derived equation. Both methods yield liquid level measurements with errors of approx. 5%. A sensitivity study on probe performance at reactor conditions predicts reduced level responsivity from data at lower temperatures

Study on the incore fuel management of RSG-GAS reactor

International Nuclear Information System (INIS)

Kuntjoro, S.; Sutiarso, K.; Praptoriadi, G.

1995-01-01

The RSG-GAS reactor was designed to work at nominal thermal power of 30 MW with average thermal neutron flux of 2.10 -14 cm -2 s -1 . Forty fuel assemblies and eight control assemblies are expected to form the typical working core (TWC) so that the pattern of the in-core fel management could be carried out properly. One of the requested safety conditions is that the reactor could still be shut down even if the control assemblies with highest negative reactivity were in failure work properly. It is not possible, with respect to the prerequested safety condition, to construct directly a typical working core. Utilizing the IAFUEL code program, a series of transition cores (the cores before reaching the TWC) were set up. The TWC is expected to be reached after eight transition cores. (author)

Miocarditis eosinofílica como causa de disfunción ventricular izquierda reversible

Directory of Open Access Journals (Sweden)

María Juliana Rodríguez-González

2017-01-01

Se logra el destete del soporte circulatorio, presenta mejoría de la función sistólica del ventrículo izquierdo con recuperación total del cuadro clínico. Este caso es relevante en cuanto a diagnóstico de disfunción ventricular aguda, con una asociación previamente no descrita con antimoniato de meglumina (glucantime, nos recuerda la importancia de realizar: la biopsia endomiocárdica para definir la etiología, la toma de decisiones de terapias avanzadas, conociendo que en ciertas circunstancias puede presentarse reversibilidad de la disfunción miocárdica y mejoría del cuadro clínico.

Stress induced right ventricular dysfunction: An indication of reversible right ventricular ischaemia

International Nuclear Information System (INIS)

Underwood, S.R.; Walton, S.; Emanuel, R.W.; Swanton, R.H.; Campos Costa, D.; Laming, P.J.; Ell, P.J.

1987-01-01

Stress induced changes in left ventricular ejection fraction are widely used in the detection and assessment of coronary artery disease. This study demonstrates that right ventricular dysfunction may also occur, and assesses its significance in terms of coronary artery anatomy. This study involved 14 normal subjects and 26 with coronary artery disease investigated by equilibrium radionuclide ventriculography, at rest and during maximal dynamic exercise. Mean normal resting right ventricular ejection fraction (RVEF) was 0.40 (SD 0.118), and all normal subjects increased RVEF with stress (mean ΔRVEF+0.13 SD 0.099). Mean ΔRVEF in the subjects with coronary artery disease was significantly lower at 0.00 (SD 0.080), but there was overlap between the two groups. The largest falls in RVEF were seen if the right coronary artery was occluded without retrograde filling. In this subgroup with the most severely compromised right ventricular perfusion (nine subjects), RVEF always fell with stress, and mean ΔRVEF was -0.08 (SD 0.050). There was no significant correlation between ΔLVEF and ΔRVEF, implying that the right ventricular dysfunction was due to right ventricular ischaemia, rather than secondary to left ventricular dysfunction. Stress induced right ventricular ischaemia can therefore be detected readily by radionuclide ventriculography. (orig.)

Fibrilação ventricular durante atividade esportiva tratada com sucesso Fibrilación ventricular durante actividad deportiva tratada con êxito Ventricular fibrillation during sport activity successfully treated

Directory of Open Access Journals (Sweden)

Maria Margarita Gonzalez

2009-08-01

Full Text Available A sobrevida após parada cardio-respiratória extra-hospitalar é estimada em menos de 5%. Apresentamos um caso de fibrilação ventricular, durante atividade esportiva. Ressuscitação cardio-pulmonar foi iniciada precocemente por pessoa leiga, e desfibrilação foi realizada em menos de três minutos, com desfibrilador externo automático, com sucesso. O programa de acesso público à desfibrilação tem aumentado a sobrevida após fibrilação ventricular extra-hospitalar. Devemos estimular o treinamento de pessoas leigas com relação ao uso de desfibriladores externos automáticos e o programa Suporte Básico de Vida, incentivando a implementação deste em locais com grande afluxo de pessoas e locais com risco elevado de ocorrer morte súbita, a exemplo de centros esportivos.La sobrevida tras una parada cardiorrespiratoria extrahospitalaria se estima en menos del 5%. Presentamos un caso de fibrilación ventricular durante actividad deportiva La resucitación cardiopulmonar fue iniciada precozmente por personal no técnico, y la desfibrilación se realizó en menos de tres minutos, con desfibrilador externo automático, con éxito. El programa de acceso público a la desfibrilación aumentó la sobrevida después de la fibrilación ventricular extrahospitalaria. Debemos estimular la capacitación de personas no técnicas con relación al uso de desfibriladores externos automáticos y el programa Soporte Básico de Vida, incentivando la implementación del mismo en locales con gran afluencia de personas y locales con riesgo elevado de ocurrencia de muerte súbita, como es el caso de los centros deportivos.Survival after out-of-hospital cardiopulmonary arrest is estimated at less than 5%. We report a case of ventricular fibrillation during sports activity. Cardiopulmonary resuscitation was initiated early by a layperson, and defibrillation was successfully performed within less than three minutes, with an automated external defibrillator. The

Layout of PWR in-core instrumentation system tubing and support structure with Bechtel 3D-CADD

International Nuclear Information System (INIS)

Ichikawa, T.; Pfeifer, B.W.; Mulay, J.N.

1987-01-01

The optimization study of the PWR In-Core Instrumentation System (ICIS) tubing layout and support structure presented an opportunity to utilize the Bechtel 3D-CADD program to perform this task. This paper provides a brief summary of the Bechtel 3D-CADD program development and capabilities and outlines the process of developing and optimizing the ICIS tube layout. Specific aspects relating to the ICIS tube layout criteria, support, alignment, electronic interference check and erection sequence are provided. (orig.)

Systolic ventricular filling.

Science.gov (United States)

Torrent-Guasp, Francisco; Kocica, Mladen J; Corno, Antonio; Komeda, Masashi; Cox, James; Flotats, A; Ballester-Rodes, Manel; Carreras-Costa, Francesc

2004-03-01

The evidence of the ventricular myocardial band (VMB) has revealed unavoidable coherence and mutual coupling of form and function in the ventricular myocardium, making it possible to understand the principles governing electrical, mechanical and energetical events within the human heart. From the earliest Erasistratus' observations, principal mechanisms responsible for the ventricular filling have still remained obscured. Contemporary experimental and clinical investigations unequivocally support the attitude that only powerful suction force, developed by the normal ventricles, would be able to produce an efficient filling of the ventricular cavities. The true origin and the precise time frame for generating such force are still controversial. Elastic recoil and muscular contraction were the most commonly mentioned, but yet, still not clearly explained mechanisms involved in the ventricular suction. Classical concepts about timing of successive mechanical events during the cardiac cycle, also do not offer understandable insight into the mechanism of the ventricular filling. The net result is the current state of insufficient knowledge of systolic and particularly diastolic function of normal and diseased heart. Here we summarize experimental evidence and theoretical backgrounds, which could be useful in understanding the phenomenon of the ventricular filling. Anatomy of the VMB, and recent proofs for its segmental electrical and mechanical activation, undoubtedly indicates that ventricular filling is the consequence of an active muscular contraction. Contraction of the ascendent segment of the VMB, with simultaneous shortening and rectifying of its fibers, produces the paradoxical increase of the ventricular volume and lengthening of its long axis. Specific spatial arrangement of the ascendent segment fibers, their interaction with adjacent descendent segment fibers, elastic elements and intra-cavitary blood volume (hemoskeleton), explain the physical principles

Application of Integral Ex-Core and Differential In-Core Neutron Measurements for Adjustment of Fuel Burn-Up Distributions in VVER-1000

Science.gov (United States)

Borodkin, Pavel G.; Borodkin, Gennady I.; Khrennikov, Nikolay N.

2010-10-01

The paper deals with calculational and semi-analytical evaluations of VVER-1000 reactor core neutron source distributions and their influence on measurements and calculations of the integral through-vessel neutron leakage. Time-integrated neutron source distributions used for DORT calculations were prepared by two different approaches based on a) calculated fuel burn-up (standard routine procedure) and b) in-core measurements by means of SPD & TC (new approach). Taking into account that fuel burn-up distributions in operating VVER may be evaluated now by analytical methods (calculations) only it is needed to develop new approaches for testing and correction of calculational evaluations. Results presented in this paper allow to consider a reverse task of alternative estimation of fuel burn-up distributions. The approach proposed is based on adjustment (fitting) of time-integrated neutron source distributions, and hence fuel burn-up patterns in some part of reactor core, on the base of ex-core neutron leakage measurement, neutron-physical calculation and in-core SPD & TC measurement data.

SORO post-simulations of Bruce A Unit 4 in-core flux detector verification tests

Energy Technology Data Exchange (ETDEWEB)

Braverman, E.; Nainer, O. [Bruce Power, Nuclear Safety Analysis and Support Dept., Toronto, Ontario (Canada)]. E-mail: Evgeny.Braverman@brucepower.com; Ovidiu.Nainer@brucepower.com

2004-07-01

During the plant equipment assessment prior to requesting approval for restart of Bruce A Units 3 and 4 it was determined that all in-core flux detectors needed to be replaced. Flux detector verification tests were performed to confirm that the newly installed detectors had been positioned according to design specifications and that their response closely follows the calculated flux shape changes caused by selected reactivity mechanism movements. By comparing the measured and post-simulated RRS and NOP detector responses to various perturbations, it was confirmed that the new detectors are wired and positioned correctly. (author)

Bloqueo aurículo-ventricular de primer grado en tirotoxicosis aguda First degree atrio-ventricular block in acute thyrotoxicosis

Directory of Open Access Journals (Sweden)

Antonio R. Vilches

2004-02-01

Full Text Available El cuadro clínico de la tirotoxicosis incluye síntomas cardiovasculares variados. La taquicardia sinusal es el trastorno electrocardiográfico más frecuente y los trastornos de conducción son extremadamente raros como modo de presentación. Comunicamos un caso de bloqueo aurículo-ventricular de primer grado en una paciente con hipertiroidismo recién diagnosticado y que comenzó días antes de la consulta con un cuadro general inespecífico. Su evaluación ulterior demostró que se trataba de una tirotoxicosis aguda autoinmune, y su tratamiento con metimazol corrigió el trastorno totalmente. Se discuten los mecanismos fisiopatológicos involucrados y las implicancias clínicas desde el punto de vista del internista.Thyrotoxicosis may present with a variety of cardiovascular symptoms. Sinus tachycardia is the most frequently encountered electrocardiographic abnormality and conduction disturbances are extremely uncommon. We present a case of first degree atrio-ventricular block in a patient with newly diagnosed hyperthyroidism and discuss the underlying pathophysiological mechanisms and the clinical implications from the internist’s standpoint.

Development of in-core measuring method using optical techniques

International Nuclear Information System (INIS)

Kakuta, Tsunemi; Shikama, Tatsuo; Narui, Minoru; Sagawa, Tsutomu.

1994-01-01

Since applying to more severe radiation environments in nuclear plants, e.g., in-core measuring systems, diagnostics for fusion reactors, radiation related subjects should be considered by more severe radiation and environmental conditions. Owing to this, preliminary studies of heavy neutron irradiation effects on optical fibers are conducted in the core region of fission reactor. Two kinds of SiO 2 core optical fibers, highly pure SiO 2 with OH content core and SiO 2 with fluorine doped core, were irradiated in the core region of Japan Material Testing Reactor (JMTR). Both fibers were irradiated with fast neutron (E>1.0 MeV) fluence of about 1.6x10 19 n/cm 2 and gamma-ray doses of 3.3x10 9 Gy. The optical absorption and the light-emission spectrum were measured in-situ along the irradiation. This paper mainly outlines the fundamental effects of neutron irradiation and discuss the possibility of neutron detection in the core region of reactor. (J.P.N.)

In-core sipping method for the identification of failed fuel assemblies

International Nuclear Information System (INIS)

Wu Zhongwang; Zhang Yajun

2000-01-01

The failed fuel assembly identification system is an important safety system which ensures safe operations of reactor and immediate treatment of failed fuel rod cladding. The system uses an internationally recognized method to identify failed fuel assemblies in a reactor with fuel element cases. The in-core sipping method is customary used to identify failed fuel assemblies during refueling or after fuel rod cladding failure accidents. The test is usually performed after reactor shutdown by taking samples from each fuel element case while the cases are still in their original core positions. The sample activity is then measured to identify failed fuel assemblies. A failed fuel assembly identification system was designed for the NHR-200 based on the properties of the NHR-200 and national requirements. the design provides an internationally recognized level of safety to ensure the safety of NHR-200

Development of In-Core Protection System

International Nuclear Information System (INIS)

Cho, J. H; Kim, C. H.; Kim, J. H.; Jeong, S. H.; Sohn, S. D.; BaeK, S. M.; YOON, J. H.

2016-01-01

In-core Protection System (ICOPS) is an on-line digital computer system which continuously calculates Departure from Nucleate Boiling Ratio (DNBR) and Local Power Density (LPD) based on plant parameters to make trip decisions based on the computations. The function of the system is the same as that of Core Protection Calculator System (CPCS) and Reactor Core Protection System (RCOPS) which are applied to Optimized Power Reactor 1000 (OPR1000) and Advanced Power Reactor 1400 (APR1400). The ICOPS has been developed to overcome the algorithm related obstacles in overseas project. To achieve this goal, several algorithms were newly developed and hardware and software design was updated. The functional design requirements document was developed by KEPCO-NF and the component design was conducted by Doosan. System design and software implementation were performed by KEPCO-E and C, and software Verification and Validation (V and V) was performed by KEPCO-E and C and Sure Softtech. The ICOPS has been developed to overcome the algorithm related obstacles in overseas project. The function of I/O simulator was improved even though the hardware platform is the same as that of RCOPS for Shin-Hanul 1 and 2. SCADE was applied to the implementation of ICOPS software, and the V and V system for ICOPS which satisfies international standards was developed. Although several further detailed design works remain, the function of ICOPS has been confirmed. The ICOPS will be applied to APR+ project, and the further works will be performed in following project

Development of In-Core Protection System

Energy Technology Data Exchange (ETDEWEB)

Cho, J. H; Kim, C. H.; Kim, J. H.; Jeong, S. H.; Sohn, S. D.; BaeK, S. M.; YOON, J. H. [KEPCO Engineering and Construction Co., Deajeon (Korea, Republic of)

2016-10-15

In-core Protection System (ICOPS) is an on-line digital computer system which continuously calculates Departure from Nucleate Boiling Ratio (DNBR) and Local Power Density (LPD) based on plant parameters to make trip decisions based on the computations. The function of the system is the same as that of Core Protection Calculator System (CPCS) and Reactor Core Protection System (RCOPS) which are applied to Optimized Power Reactor 1000 (OPR1000) and Advanced Power Reactor 1400 (APR1400). The ICOPS has been developed to overcome the algorithm related obstacles in overseas project. To achieve this goal, several algorithms were newly developed and hardware and software design was updated. The functional design requirements document was developed by KEPCO-NF and the component design was conducted by Doosan. System design and software implementation were performed by KEPCO-E and C, and software Verification and Validation (V and V) was performed by KEPCO-E and C and Sure Softtech. The ICOPS has been developed to overcome the algorithm related obstacles in overseas project. The function of I/O simulator was improved even though the hardware platform is the same as that of RCOPS for Shin-Hanul 1 and 2. SCADE was applied to the implementation of ICOPS software, and the V and V system for ICOPS which satisfies international standards was developed. Although several further detailed design works remain, the function of ICOPS has been confirmed. The ICOPS will be applied to APR+ project, and the further works will be performed in following project.

Using the graphs models for evaluating in-core monitoring systems reliability by the method of imiting simulaton

International Nuclear Information System (INIS)

Golovanov, M.N.; Zyuzin, N.N.; Levin, G.L.; Chesnokov, A.N.

1987-01-01

An approach for estimation of reliability factors of complex reserved systems at early stages of development using the method of imitating simulation is considered. Different types of models, their merits and lacks are given. Features of in-core monitoring systems and advosability of graph model and graph theory element application for estimating reliability of such systems are shown. The results of investigation of the reliability factors of the reactor monitoring, control and core local protection subsystem are shown

Taquicardia ventricular del tracto de salida del ventrículo derecho durante el embarazo Right ventricular outflow tachycardia during pregnancy

Directory of Open Access Journals (Sweden)

Ariel K. Saad

2012-06-01

Full Text Available Durante el embarazo aumentan el metabolismo basal, el consumo de O2, la frecuencia cardíaca, el volumen sistólico, el volumen minuto y la volemia y disminuyen la tensión arterial y la resistencia periférica. Diferentes estudios han demostrado que durante este período la posibilidad de que ocurra una arritmia cardíaca o se produzca la exacerbación de una arritmia preexistente es mayor. No obstante, en su enorme mayoría carecen de importancia pronóstica tanto para la madre como para el feto. La taquicardia ventricular del tracto de salida del ventrículo derecho es una arritmia poco frecuente y su aparición se ha correlacionado con el aumento del tono adrenérgico. Se presentan los casos de dos pacientes que mostraron en el curso de la gestación reiterados episodios de taquicardia ventricular del tracto de salida del ventrículo derecho. Se analiza la asociación del embarazo con la ocurrencia de trastornos del ritmo cardíaco.During pregnancy, there is an increase in metabolism, oxygen consumption, heart rate, stroke volume, cardiac output, blood volume and a decrease in blood pressure and peripheral resistance. Studies have shown that during this period the occurrence of cardiac arrhythmias is not uncommon. Fortunately, malignant arrhythmias are rare. Herein we report two young patients who presented with symptomatic right ventricular outflow tachycardia during pregnancy that required antiarrhythmic therapy. Possible pathophysiologic mechanisms are discussed.

Relationship between Fibrosis and Ventricular Arrhythmias in Chagas Heart Disease Without Ventricular Dysfunction

Energy Technology Data Exchange (ETDEWEB)

Tassi, Eduardo Marinho, E-mail: etassi@ibest.com.br [Instituto de Cardiologia Edson Saad - Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil); Continentino, Marcelo Abramoff [Hospital Frei Galvão, Guaratinguetá, SP (Brazil); Nascimento, Emília Matos do; Pereira, Basílio de Bragança [Instituto de Cardiologia Edson Saad - Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil); Coppe - Instituto Alberto Luiz Coimbra de Pós-Graduação e Pesquisa de Engenharia - UFRJ, Rio de Janeiro, RJ (Brazil); Pedrosa, Roberto Coury [Instituto de Cardiologia Edson Saad - Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)

2014-05-15

Patients with Chagas disease and segmental wall motion abnormality (SWMA) have worse prognosis independent of left ventricular ejection fraction (LVEF). Cardiac magnetic resonance (CMR) is currently the best method to detect SWMA and to assess fibrosis. To quantify fibrosis by using late gadolinium enhancement CMR in patients with Chagas disease and preserved or minimally impaired ventricular function (> 45%), and to detect patterns of dependence between fibrosis, SWMA and LVEF in the presence of ventricular arrhythmia. Electrocardiogram, treadmill exercise test, Holter and CMR were carried out in 61 patients, who were divided into three groups as follows: (1) normal electrocardiogram and CMR without SWMA; (2) abnormal electrocardiogram and CMR without SWMA; (3) CMR with SWMA independently of electrocardiogram. The number of patients with ventricular arrhythmia in relation to the total of patients, the percentage of fibrosis, and the LVEF were, respectively: Group 1, 4/26, 0.74% and 74.34%; Group 2, 4/16, 3.96% and 68.5%; and Group 3, 11/19, 14.07% and 55.59%. Ventricular arrhythmia was found in 31.1% of the patients. Those with and without ventricular arrhythmia had mean LVEF of 59.87% and 70.18%, respectively, and fibrosis percentage of 11.03% and 3.01%, respectively. Of the variables SWMA, groups, age, LVEF and fibrosis, only the latter was significant for the presence of ventricular arrhythmia, with a cutoff point of 11.78% for fibrosis mass (p < 0.001). Even in patients with Chagas disease and preserved or minimally impaired ventricular function, electrical instability can be present. Regarding the presence of ventricular arrhythmia, fibrosis is the most important variable, its amount being proportional to the complexity of the groups.

Relationship between Fibrosis and Ventricular Arrhythmias in Chagas Heart Disease Without Ventricular Dysfunction

International Nuclear Information System (INIS)

Tassi, Eduardo Marinho; Continentino, Marcelo Abramoff; Nascimento, Emília Matos do; Pereira, Basílio de Bragança; Pedrosa, Roberto Coury

2014-01-01

Patients with Chagas disease and segmental wall motion abnormality (SWMA) have worse prognosis independent of left ventricular ejection fraction (LVEF). Cardiac magnetic resonance (CMR) is currently the best method to detect SWMA and to assess fibrosis. To quantify fibrosis by using late gadolinium enhancement CMR in patients with Chagas disease and preserved or minimally impaired ventricular function (> 45%), and to detect patterns of dependence between fibrosis, SWMA and LVEF in the presence of ventricular arrhythmia. Electrocardiogram, treadmill exercise test, Holter and CMR were carried out in 61 patients, who were divided into three groups as follows: (1) normal electrocardiogram and CMR without SWMA; (2) abnormal electrocardiogram and CMR without SWMA; (3) CMR with SWMA independently of electrocardiogram. The number of patients with ventricular arrhythmia in relation to the total of patients, the percentage of fibrosis, and the LVEF were, respectively: Group 1, 4/26, 0.74% and 74.34%; Group 2, 4/16, 3.96% and 68.5%; and Group 3, 11/19, 14.07% and 55.59%. Ventricular arrhythmia was found in 31.1% of the patients. Those with and without ventricular arrhythmia had mean LVEF of 59.87% and 70.18%, respectively, and fibrosis percentage of 11.03% and 3.01%, respectively. Of the variables SWMA, groups, age, LVEF and fibrosis, only the latter was significant for the presence of ventricular arrhythmia, with a cutoff point of 11.78% for fibrosis mass (p < 0.001). Even in patients with Chagas disease and preserved or minimally impaired ventricular function, electrical instability can be present. Regarding the presence of ventricular arrhythmia, fibrosis is the most important variable, its amount being proportional to the complexity of the groups

Quantum behaved Particle Swarm Optimization with Differential Mutation operator applied to WWER-1000 in-core fuel management optimization

International Nuclear Information System (INIS)

Jamalipour, Mostafa; Sayareh, Reza; Gharib, Morteza; Khoshahval, Farrokh; Karimi, Mahmood Reza

2013-01-01

Highlights: ► A new method called QPSO-DM is applied to BNPP in-core fuel management optimization. ► It is found that QPSO-DM performs better than PSO and QPSO. ► This method provides a permissible arrangement for optimum loading pattern. - Abstract: This paper presents a new method using Quantum Particle Swarm Optimization with Differential Mutation operator (QPSO-DM) for optimizing WWER-1000 core fuel management. Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) have shown good performance on in-core fuel management optimization (ICFMO). The objective of this paper is to show that QPSO-DM performs very well and is comparable to PSO and Quantum Particle Swarm Optimization (QPSO). Most of the strategies for ICFMO are based on maximizing multiplication factor (k eff ) to increase cycle length and minimizing power peaking factor (P q ) in order to improve fuel integrity. PSO, QPSO and QPSO-DM have been implemented to fulfill these requirements for the first operating cycle of WWER-1000 Bushehr Nuclear Power Plant (BNPP). The results show that QPSO-DM performs better than the others. A program has been written in MATLAB to map PSO, QPSO and QPSO-DM for loading pattern optimization. WIMS and CITATION have been used to simulate reactor core for neutronic calculations

First experience from in-core sensor validation based on correlation and neuro-fuzzy techniques

International Nuclear Information System (INIS)

Figedy, S.

2011-01-01

In this work new types of nuclear reactor in-core sensor validation methods are outlined. The first one is based on combination of correlation coefficients and mutual information indices, which reflect the correlation of signals in linear and nonlinear regions. The method may be supplemented by wavelet transform based signal features extraction and pattern recognition by artificial neural networks and also fuzzy logic based decision making. The second one is based on neuro-fuzzy modeling of residuals between experimental values and their theoretical counterparts obtained from the reactor core simulator calculations. The first experience with this approach is described and further improvements to enhance the outcome reliability are proposed (Author)

Results of an analysis of in-core measurements during the first core cycle of the Greifswald nuclear power plant, unit 3

International Nuclear Information System (INIS)

Gehre, G.

1982-01-01

First results of an analysis of flux and temperature values obtained from the in-core system in the third unit of the Greifswald nuclear power plant during the first core cycle are presented. The analysis has been performed with the aid of the computer code INCA. Possibilities and limits of this code are shown. (author)

Amiodarone for the treatment and prevention of ventricular fibrillation and ventricular tachycardia

Directory of Open Access Journals (Sweden)

Hugo Van Herendael

2010-06-01

Full Text Available Hugo Van Herendael, Paul DorianDivision of Cardiology, St. Michael’s Hospital, University of Toronto, Toronto, CanadaAbstract: Amiodarone has emerged as the leading antiarrhythmic therapy for termination and prevention of ventricular arrhythmia in different clinical settings because of its proven efficacy and safety. In patients with shock refractory out-of-hospital cardiac arrest and hemodynamically destabilizing ventricular arrhythmia, amiodarone is the most effective drug available to assist in resuscitation. Although the superiority of the transvenous implantable cardioverter defibrillator (ICD over amiodarone has been well established in the preventive treatment of patients at high risk of life-threatening ventricular arrhythmias, amiodarone (if used with a beta-blocker is the most effective antiarrhythmic drug to prevent ICD shocks and treat electrical storm. Both the pharmacokinetics and the electrophysiologic profile of amiodarone are complex, and its optimal and safe use requires careful patient surveillance with respect to potential adverse effects.Keywords: amiodarone, ventricular fibrillation, unstable ventricular tachycardia

The overloaded right heart and ventricular interdependence.

Science.gov (United States)

Naeije, Robert; Badagliacca, Roberto

2017-10-01

The right and the left ventricle are interdependent as both structures are nested within the pericardium, have the septum in common and are encircled with common myocardial fibres. Therefore, right ventricular volume or pressure overloading affects left ventricular function, and this in turn may affect the right ventricle. In normal subjects at rest, right ventricular function has negligible interaction with left ventricular function. However, the right ventricle contributes significantly to the normal cardiac output response to exercise. In patients with right ventricular volume overload without pulmonary hypertension, left ventricular diastolic compliance is decreased and ejection fraction depressed but without intrinsic alteration in contractility. In patients with right ventricular pressure overload, left ventricular compliance is decreased with initial preservation of left ventricular ejection fraction, but with eventual left ventricular atrophic remodelling and altered systolic function. Breathing affects ventricular interdependence, in healthy subjects during exercise and in patients with lung diseases and altered respiratory system mechanics. Inspiration increases right ventricular volumes and decreases left ventricular volumes. Expiration decreases both right and left ventricular volumes. The presence of an intact pericardium enhances ventricular diastolic interdependence but has negligible effect on ventricular systolic interdependence. On the other hand, systolic interdependence is enhanced by a stiff right ventricular free wall, and decreased by a stiff septum. Recent imaging studies have shown that both diastolic and systolic ventricular interactions are negatively affected by right ventricular regional inhomogeneity and prolongation of contraction, which occur along with an increase in pulmonary artery pressure. The clinical relevance of these observations is being explored. Published on behalf of the European Society of Cardiology. All rights

The influence of homogenization on the calculation of the sensitivity volume of a BWR incore detector

International Nuclear Information System (INIS)

Haghighat, A.; Kosaly, G.

1985-01-01

By performing two-group, X-Y, S 4 transport theory calculations with the albedo boundary condition, the effect of heterogeneities on the BWR incore detector has been investigated. The albedo distribution along the boundary of the control volume is obtained using a two-group, homogenous, X-Y diffusion model. Different degrees of homogenization have been examined. Investigation shows that a cell-homogeneous model, with separated bypass region and inner water gap, is a viable alternative to the heterogeneous approach. This finding contradicts earlier predictions of a need for a heterogeneous model. (author)

Contractilidad del músculo ventricular bajo la acción de prajmalina-propanolol y prajmalina-epinefrina Contractibility of the ventricular muscle under the action of prajmaline-propanolol and prajmaline-epinephrine

Directory of Open Access Journals (Sweden)

Jorge Pérez Valdivia

2005-03-01

Full Text Available Los efectos de la estimulación adrenérgica alfa y beta, pueden ser logrados por agentes agonistas y antagonistas, como la epinefrina y el propranolol respectivamente. Con el objetivo de precisar aspectos relacionados con la contractilidad del músculo ventricular, se realizaron un total de trece experimentos utilizando combinaciones de prajmalina-epinefrina y prajmalina-propanolol, prefundiendo preparaciones de tiras de músculo ventricular de trece ejemplares adultos de ranas catesbeiana. La prajmalina, antiarrítmico del grupo I, se obtuvo a partir de la Rauvvolfia viridis, planta endémica de Cuba. Las preparaciones fueron estimuladas con pulsos de corriente, y la tensión desarrollada por el músculo fue registrada por un transductor fuerza-desplazamiento. Las señales eléctricas fueron convertidas en trazos por un equipo registrador. Los resultados indican que las combinaciones de prajmalina-epinefrina y prajmanina-propanolol afectan de forma diametralmente opuesta la contractilidad del músculo cardíaco, aumentando en un 40% y disminuyendo en un 15% respectivamente la fuerza de la contracción del músculo ventricular. Por otra parte se sugiere un posible mecanismo de acción de la prajmalina sobre los receptores alfa presentes en las membranas de las células ventriculares.The effects of alfa and beta adrenergic stimulation can be accomplished by agonist and antagonist agents such as epinephrine and propanolol respectively. Aimed at determining the aspects related to contractibility of ventricular muscle, thirteen experiments were performed using combinations of prajmaline "epinephrine and prajmaline" propanolol, being perfused preparations of ventricular muscle strips of thirteen samples of adult Catesblian frogs. Prajmaline, a group I antiarrhythmic, was obtained from Rauvvolfia viridis, an endemic plant in Cuba. The preparations were stimulated with electric current pulses and the tension performed by the muscle was registered by a

Surgery for ventricular tachycardia in patients undergoing surgical ventricular restoration: the Karolinska approach.

Science.gov (United States)

Sartipy, Ulrik; Albåge, Anders; Insulander, Per; Lindblom, Dan

2007-09-01

This article presents a review on the efficacy of surgical ventricular restoration and direct surgery for ventricular tachycardia in patients with left ventricular aneurysm or dilated ischemic cardiomyopathy. The procedure includes a non-electrophysiologically guided subtotal endocardiectomy and cryoablation in addition to endoventricular patch plasty of the left ventricle. Coronary artery bypass surgery and mitral valve repair are performed concomitantly as needed. In our experience, this procedure yielded a 90% success rate in terms of freedom from spontaneous ventricular tachycardia, with an early mortality rate of 3.8%. A practical guide to the pre- and postoperative management of these patients is provided.

[The reasonable use of right ventricular protection strategy in right ventricular outflow tract reconstruction].

Science.gov (United States)

Zhang, Y; Yuan, H Y; Liu, X B; Wen, S S; Xu, G; Cui, H J; Zhuang, J; Chen, J M

2018-06-01

As a result of right ventricular outflow tract reconstruction, which is the important and basic step of complex cardiac surgery, the blood flow of right ventricular outflow tract is unobstructed, while pulmonary valve regurgitation and right heart dysfunction could be happened. These problems are often ignored in early days, more and more cases of right heart dysfunction need clinical intervention, which is quite difficult and less effective. How to protect effectively the right ventricular function is the focus. At present main methods to protect the right ventricular function include trying to avoid or reduce length of right ventricular incision, reserving or rebuilding the function of the pulmonary valve, using growth potential material for surgery. The protection of the right ventricular function is a systemic project, it involves many aspects, single measures is difficult to provide complete protection, only the comprehensive use of various protection strategy, can help to improve the long-term prognosis.

In-core fuel management for nuclear reactor

International Nuclear Information System (INIS)

Ross, M.F.; Visner, S.

1986-01-01

This patent describes in-core fuel management for nuclear reactor in which the first cycle of a pressurized water nuclear power reactor has a multiplicity of elongated, square fuel assemblies supported side-by-side to form a generally cylindrical, stationary core consisting entirely of fresh fuel assemblies. Each assembly of the first type has a substantially similar low average fissile enrichment of at least about 1.8 weight percent U-235, each assembly of the second type having a substantially similar intermediate average fissile enrichment at least about 0.4 weight percent greater than that of the first type, and each assembly of the third type having a substantially similar high average fissile enrichment at least about 0.4 weight percent greater than that of the intermediate type, the arrangement of the low, intermediate, and high enrichment assembly types which consists of: a generally cylindrical inner core region consisting of approximately two-thirds the total assemblies in the core and forming a figurative checkerboard array having a first checkerboard component at least two-thirds of which consists of high enrichment and intermediate enrichment assemblies, at least some of the high enrichment assemblies containing fixed burnable poison shims, and a second checkerboard component consisting of assemblies other than the high enrichment type; and a generally annular outer region consisting of the remaining assemblies and including at least some but less than two-thirds of the high enrichment type assemblies

Test of In-core Flux Detectors in KNK II

International Nuclear Information System (INIS)

Hoppe, P.; Mitzel, F.

1979-10-01

The development of in-core detectors for Liquid Metal Fast Breeder Reactors (LMFBRs) is still in an early stage, and little operation experience is available. Therefore self-powered neutron and gamma detectors and neutron sensitive ionization chambers -especially developed for LMFBRs- have been tested in the Fast Sodium Cooled Test Reactor KNK II. Seven flux detectors have been installed in the core of KNK II by means of a special test rig. Five of them failed already within the first week during operation in the reactor. Due to measurements of electrical resistances and capacities, sodium penetrating into the detectors or cables probably seems to be the cause. As tests prior to the installation in the core proved the tightness of all detectors, it is suspected that small cracks have developed in the detector casings or in the outer cable sheaths during their exposure to the hot coolant. Two ionization chambers did not show these faults. However, one of them failed because the saturation current plateau disappeared and the other one's sensitivity decreased by a factor of five during the test period. It is suspected that in both cases changes of the filling gas might be involved

Right Ventricular Endomyocardial Fibrosis Presenting With Ventricular Tachycardia And Apical Thrombus - An Interesting Presentation

Directory of Open Access Journals (Sweden)

Amitesh Aggarwal

2009-11-01

Full Text Available Endomyocardial fibrosis is a progressive disease of unknown origin affecting children and young adults. It involves inflow portion of right and/or left ventricle and apex. It may be associated with thrombus. Literature regarding right ventricular endomyocardial fibrosis with thrombus is scarce. Here we report a rare case of right ventricular endomyocardial fibrosis presenting as ventricular tachycardia and echocardiographic evidence of apical thrombus. Interestingly there was no pulmonary involvement or evidence of deep venous thrombosis. This case also underscores the importance of urgent echocardiography in diagnosis of obscure cases of ventricular tachycardia.

Experimental Study of Hydraulic Control Rod Drive Mechanism for Passive IN-core Cooling System of Nuclear Power Plant

Energy Technology Data Exchange (ETDEWEB)

Kim, In Guk; Kim, Kyung Mo; Jeong, Yeong Shin; Bang, In Cheol [KAERI, Daejeon (Korea, Republic of)

2016-05-15

CAREM 25 (27 MWe safety systems using hydraulic control rod drives (CRD) studied critical issues that were rod drops with interrupted flow [3]. Hydraulic control rod drive suggested fast shutdown condition using a large gap between piston and cylinder in order to fast drop of neutron absorbing rods. A Passive IN-core Cooling system (PINCs) was suggested for safety enhancement of pressurized water reactors (PWR), small modular reactor (SMR), sodium fast reactor (SFR) in UNIST. PINCs consist of hydraulic control rod drive mechanism (Hydraulic CRDM) and hybrid control rod assembly with heat pipe combined with control rod. The schematic diagram of the hydraulic CRDM for PINCs is shown in Fig. 1. The experimental results show the steady state and transient behavior of the upper cylinder at a low pressure and low temperature. The influence of the working fluid temperature and cylinder mass are investigated. Finally, the heat removal between evaporator section and condenser section is compared with or without the hybrid control rod. Heat removal test of the hybrid heat pipe with hydraulic CRDM system showed the heat transfer coefficient of the bundle hybrid control rod and its effect on evaporator pool. The preliminary test both hydraulic CRDM and heat removal system was conducted, which showed the possibility of the in-core hydraulic drive system for application of PINCs.

Modernization in-core monitoring system, of WWER-1000 reactors (W-320) by fuel assemblies with individual characteristics using

International Nuclear Information System (INIS)

Mitin, V. I.; Semchenkov, J. M.; Kalinushkin, A. E.

2007-01-01

The present report covers object, conception, engineering solution of construction of modern system of high-powered reactor in-core control, including WWER-1000 (V-320) reactors. It is known that ICMS main task is on-line monitoring distribution of power release field and its functioning independently of design programs to avoid common reason error. It is shown in what way field of power release recovery has been carrying on; rest on the signals of in-core neutron and temperature sensors. On the base of the obtained and refined information there have being automatically generated signals of preventive and emergency protection on local parameters (linear power to the maximum intensive fuel elements, reserve to heat exchange crisis, 'picking factor'). There have represented technology on sensors and processing methods of SPND and TC signals, ICIS composition and structure, program hard ware, system and applied software. Structure, composition and the taken decisions allow combining class 1E and class B and C tasks in accordance with international norms of separation and safety classes' realization. At present ICIS-M is a system, providing implementation of control, safety, information and diagnostic functions, which allow securing actual increase of quality, reliability and safety in operation of nuclear fuel and NPP units. And at the same time it reduces human factor negative influence to core work thermo technical eliability in the operational process (Authors)

Right Ventricular Outflow Tract Tachycardia with Structural Abnormalities of the Right Ventricle and Left Ventricular Diverticulum

Directory of Open Access Journals (Sweden)

Bortolo Martini

2015-01-01

Full Text Available A 43-year-old woman presented to the emergency room with a sustained ventricular tachycardia (VT. ECG showed a QRS in left bundle branch block morphology with inferior axis. Echocardiography, ventricular angiography, and cardiac magnetic resonance imaging (CMRI revealed a normal right ventricle and a left ventricular diverticulum. Electrophysiology studies with epicardial voltage mapping identified a large fibrotic area in the inferolateral layer of the right ventricular wall and a small area of fibrotic tissue at the anterior right ventricular outflow tract. VT ablation was successfully performed with combined epicardial and endocardial approaches.

Radionuclide analysis of right and left ventricular response to exercise in patients with atrial and ventricular septal defects

International Nuclear Information System (INIS)

Peter, C.A.; Bowyer, K.; Jones, R.H.

1983-01-01

In patients with ventricular or atrial septal defect, the ventricle which is chronically volume overloaded might not appropriately respond to increased demand for an augmentation in output and thereby might limit total cardiac function. In this study we simultaneously measured right and left ventricular response to exercise in 10 normal individuals, 10 patients with ventricular septal defect (VSD), and 10 patients with atrial septal defect (ASD). The normal subjects increased both right and left ventricular ejection fraction, end-diastolic volume, and stroke volume to achieve a higher cardiac output during exercise. Patients with VSD failed to increase right ventricular ejection fraction, but increased right ventricular end-diastolic volume and stroke volume. Left ventricular end-diastolic volume did not increase in these patients but ejection fraction, stroke volume, and forward left ventricular output achieved during exercise were comparable to the response observed in healthy subjects. In the patients with ASD, no rest-to-exercise change occurred in either right ventricular ejection fraction, end-diastolic volume, or stroke volume. In addition, left ventricular end-diastolic volume failed to increase, and despite an increase in ejection fraction, left ventricular stroke volume remained unchanged from rest to exercise. Therefore, cardiac output was augmented only by the heart rate increase in these patients. Right ventricular function appeared to be the major determinant of total cardiac output during exercise in patients with cardiac septal defects and left-to-right shunt

Constant-Temperature Calorimetry for In-Core Power Measurement

International Nuclear Information System (INIS)

Radcliff, Thomas D.; Miller, Don W.; Kauffman, Andrew C.

2000-01-01

Reactor thermal limits are based on fuel energy deposition and cladding temperature. This paper presents a two-wire in-core instrument that directly measures fuel energy deposition. The instrument is based on the addition of heat through resistive dissipation of input electrical energy to a small mass of reactor fuel or fuel analogue. A feedback loop controls the input electrical energy needed to maintain the fuel mass at a nearly constant temperature regardless of the nuclear energy deposited in the mass. Energy addition to the fuel and fuel temperature feedback to the controller are provided by a resistive heating element embedded in the fuel mass. As long as the external heat transfer environment remains constant, the input electrical energy is inversely related to the actual nuclear energy deposition. To demonstrate this instrument, we first scaled the sensor and controller parameters and then used the results to guide fabrication of prototype instruments. In-reactor testing was performed to measure the instrument sensitivity, linearity, bandwidth, and long-term drift characteristics of the prototypes. The instrument is shown to be capable of high-sensitivity, linear measurement of fuel energy deposition with sufficient bandwidth for safety-related measurements. It is also clear that a means to compensate the sensor for changes in the external heat transfer environment is required. Means of actively measuring heat losses and performing this compensation are discussed

Right ventricular pressure response to exercise in adults with isolated ventricular septal defect closed in early childhood.

Science.gov (United States)

Moller, Thomas; Lindberg, Harald; Lund, May Brit; Holmstrom, Henrik; Dohlen, Gaute; Thaulow, Erik

2018-06-01

We previously demonstrated an abnormally high right ventricular systolic pressure response to exercise in 50% of adolescents operated on for isolated ventricular septal defect. The present study investigated the prevalence of abnormal right ventricular systolic pressure response in 20 adult (age 30-45 years) patients who underwent surgery for early ventricular septal defect closure and its association with impaired ventricular function, pulmonary function, or exercise capacity. The patients underwent cardiopulmonary tests, including exercise stress echocardiography. Five of 19 patients (26%) presented an abnormal right ventricular systolic pressure response to exercise ⩾ 52 mmHg. Right ventricular systolic function was mixed, with normal tricuspid annular plane systolic excursion and fractional area change, but abnormal tricuspid annular systolic motion velocity (median 6.7 cm/second) and isovolumetric acceleration (median 0.8 m/second2). Left ventricular systolic and diastolic function was normal at rest as measured by the peak systolic velocity of the lateral wall and isovolumic acceleration, early diastolic velocity, and ratio of early diastolic flow to tissue velocity, except for ejection fraction (median 53%). The myocardial performance index was abnormal for both the left and right ventricle. Peak oxygen uptake was normal (mean z score -0.4, 95% CI -2.8-0.3). There was no association between an abnormal right ventricular systolic pressure response during exercise and right or left ventricular function, pulmonary function, or exercise capacity. Abnormal right ventricular pressure response is not more frequent in adult patients compared with adolescents. This does not support the theory of progressive pulmonary vascular disease following closure of left-to-right shunts.

Four cases of right ventricular dysplasia

International Nuclear Information System (INIS)

Takamura, Ichiro; Ando, Joji; Miyamoto, Atsushi; Kobayashi, Takeshi; Sakamoto, Sanya; Yasuda, Hisakazu

1985-01-01

Finding of 81 Kr right ventriculography and 201 Tl myocardial perfusion imaging in 4 patients with right ventricular dysplasia (RVD) were compared with those in 28 patients with dilated cardiomyopathy. Remarkably dilated right ventricle was detected on 201 Tl myocardial perfusion imaging in the RVD group. In a patient with RVD who died suddenly, perfusion defect of the left ventricular myocardium, a decreased right ventricular ejection fraction, and an increased right ventricular end diastolic volume were seen. Perfusion defect of the left ventricular myocardium was seen in 10 of the 28 patients with dilated cardiomyopathy, 4 of whom died suddenly. In these 4 patients, a decreased left ventricular ejection fraction and an increased right ventricular end diastolic volume were seen. These findings obtained by the radionuclide techniques suggested that there are differences in cardiac dysfunction of the both ventricles between the groups with RVD and dilated cardiomyopathy. (Namekawa, K.)

Reconstrução fisiológica do ventrículo esquerdo: o conceito de máxima redução ventricular e mínima resposta inflamatória Physiologic left ventricular reconstruction: the concept of maximum ventricular reduction and minimum inflammatory reaction

Directory of Open Access Journals (Sweden)

Walter J. Gomes

2004-12-01

Full Text Available INTRODUÇÃO: A sobrevida em pacientes com insuficiência cardíaca, assim como após a cirurgia de reconstrução do ventrículo esquerdo (VE, está relacionada ao tamanho da cavidade ventricular esquerda. Também o uso de materiais sintéticos na reconstrução ventricular poderia induzir uma reação inflamatória crônica. Relatamos a modificação da técnica de reconstrução ventricular que elimina a necessidade de retalhos intra-cavitários e de uso de material sintético no fechamento do VE. MÉTODO: Onze pacientes consecutivos com aneurisma de VE, evoluindo em classe funcional (CF III e IV da New York Heart Association foram submetidos à cirurgia de reconstrução ventricular direta sem utilização de retalhos intra-cavitários ou materiais protéticos no fechamento da incisão ventricular. RESULTADOS: Não houve mortalidade cirúrgica ou necessidade de suporte circulatório mecânico. A permanência hospitalar pós-operatória variou de 4 a 7 dias (média de 5,3 ± 1,1 dias. O ecocardiograma de controle, realizado em média 4,6 ± 1,5 meses após a operação, evidenciou redução do diâmetro diastólico de VE de 69,0 ± 7,5 mm, no pré-operatório, para 62,6 ± 5,1 mm, no pós-operatório. A fração de ejeção do VE mostrou aumento de 47,3% ± 6,6% para 56,3% ±10,5%. Com um ano de seguimento, 8 pacientes encontram-se em CF I e 3 em CF II. CONCLUSÃO: Esta técnica, com eliminação de uso de material sintético, pode contribuir para a melhora dos resultados clínicos de pacientes submetidos à reconstrução ventricular esquerda, proporcionando virtual eliminação das áreas acinéticas do VE e potencialmente atenuando, no pós-operatório tardio, a reação inflamatória crônica do miocárdio.BACKGROUND: The outcome of patients with heart failure, as well as after left ventricular reconstruction, is related to the size of the left ventricular cavity. Also the use of synthetic materials in the ventricular reconstruction could

Application of Computational Intelligence Methods to In-Core Fuel Management

International Nuclear Information System (INIS)

Erdogan, A.

2001-01-01

In this study, a computer program package has been developed which supports the in-core fuel management activities for pressurized water reactors, generates and recommends an optimum loading pattern to ensure safe and efficient reactor operation. A search for an optimum fuel loading pattern must be conducted in the space of several core parameters such as power distribution, which is an excessively time consuming computational process. Global core calculation codes take a relatively long time to do the task. The time interval necessary for the iterative process was reduced by using an artificial neural network estimator for the calculations. In this way, it was possible to analyze more loading patterns in the same time interval and the probability of finding a desired optimum was increased. As a case study, the core of the Almaraz Nuclear Plant of Spain, a pressurized water reactor, was modeled for the core calculation code system. The 2-group cross sections for the fuel assembly types were calculated and stored for later usage with the diffusion code. 2000 loading patterns were generated by placing fuel assemblies to random positions in the core, and for each pattern the power distribution and effective multiplication factor (k e ff) were calculated with the diffusion code. At the next stage, 500 of the loading patterns were introduced to the neural network as input data for the training process. The remaining 1500 patterns were used to validate the neural network implementation. It was shown that the neural network estimates the power distribution and the K effective within acceptable error limits. To complete the system, a loading pattern generator was developed. This module consists of a set of rules and an algorithm that places the fuel assemblies to core positions. The neural network estimated the power distribution and k e ff for the loading patterns that were generated by this module. The patterns that have a maximum power fraction lower than, and a minimum

Large right ventricular sinusoids in an infant with aorta-left ventricular tunnel and proximal right coronary artery atresia.

Science.gov (United States)

Chen, Peter C; Spinner, Joseph A; Heinle, Jeffrey S

2018-07-01

We report a 1-month-old infant diagnosed with an aorta-left ventricular tunnel, ventricular septal defect, and right coronary atresia with right ventricular sinusoids. The patient's anatomy and physiology did not indicate right-ventricular-dependent coronary circulation, and therefore right ventricular decompression could be performed without compromising coronary perfusion during surgical correction. A detailed understanding of the coronary anatomy is critical in managing this defect when coronary anomalies are present.

Efeitos da estimulação ventricular convencional em pacientes com função ventricular normal Efectos de la estimulación ventricular convencional en pacientes con función ventricular normal Conventional ventricular stimulation effects on patients with normal ventricular function

Directory of Open Access Journals (Sweden)

Luiz Antonio Batista de Sá

2009-08-01

Full Text Available FUNDAMENTO: A estimulação de ventrículo direito pode ser deletéria em pacientes com disfunção ventricular, entretanto há poucas evidências sobre o impacto dessa estimulação em pacientes com função normal. OBJETIVO: Avaliar a evolução clínica e laboratorial de pacientes com função ventricular normal submetidos a implante de marcapasso cardíaco artificial. MÉTODOS: Foram estudados de forma prospectiva 16 pacientes com os seguintes critérios de inclusão: função ventricular normal definida pelo ecocardiograma e presença de estimulação ventricular superior 90% (avaliação por telemetria do gerador. Parâmetros analisados: classe funcional (CF, teste de caminhada, dosagem de BNP, ecocardiograma (convencional e parâmetros de dessincronia intraventricular e teste de qualidade de vida (SF36. Essas medidas fora feitas com 10 dias(d (t1, 120d(t2 e 240 d(t3. Os dados foram comparados ao longo do tempo segundo método ANOVA. Comparações múltiplas de médias foram efetuadas utilizando-se o método de Tukey. RESULTADOS: Dos dados avaliados os seguintes não apresentaram variação estatística significante (p>0,05: classe funcional, dosagem de BNP, parâmetros ecocardiográficos convencionais, dessincronia intraventricular (Doppler tecidual. Apresentaram piora (pFUNDAMENTO: La estimulación del ventrículo derecho puede ser dañosa a pacientes con disfunción ventricular. Sin embargo, hay pocas evidencias sobre el impacto de esa estimulación en pacientes con función normal. OBJETIVO: Evaluar la evolución clínica y laboratorial de pacientes con función ventricular normal sometidos a implante de marcapaso cardíaco artificial. MÉTODOS: Se estudiaron de forma prospectiva a 16 pacientes con los siguientes criterios de inclusión: función ventricular normal definida por el ecocardiograma y presencia de estimulación ventricular superior a 90% (evaluación por telemetría del generador. Parámetros analizados: clase funcional

Role of ventricular tachycardia ablation in arrhythmogenic right ventricular cardiomyopathy

Directory of Open Access Journals (Sweden)

Alberto Cipriani

2017-11-01

Full Text Available Arrhythmogenic right ventricular cardiomyopathy (ARVC is characterized by progressive fibro-fatty replacement of the myocardium that represents the substrate for recurrent sustained ventricular tachycardia (VT. These arrhythmias characterize the clinical course of a sizeable proportion of patients and have significant implications for their quality of life and long-term prognosis. Antiarrhythmic drugs are often poorly tolerated and usually provide incomplete control of arrhythmia relapses. Catheter ablation is a potentially effective strategy to treat frequent VT episodes and ICD shocks in ARVC patients. The aims of this review are to discuss the electrophysiological and electroanatomic substrates of ventricular tachycardia in patients with ARVC and to analyze the role of catheter ablation in their management with particular reference to selection of patients, technical issues, potential complications and outcomes.

Optimization of in-core fuel management and control rod strategy in equilibrium fuel cycle

International Nuclear Information System (INIS)

Sekimizu, Koichi

1975-01-01

An in-core fuel management problem is formulated for the equilibrium fuel cycle in an N-region nuclear reactor model. The formulation shows that the infinite multiplication factor k infinity requisite for newly charged fuel can be separated into two terms - one corresponding to the average k infinity at the end of the cycle and the other representing the direct contribution of the shuffling scheme and control rod programming. This formulation is applied to a three-region cylindrical reactor to obtain simultaneous optimization of shuffling and control rod programming. It is demonstrated that this formulation aids greatly in gaining a better understanding of the effects of changes in the shuffling scheme and control rod programming on equilibrium fuel cycle performance. (auth.)

Infarto del ventrículo derecho Right ventricular infarction

Directory of Open Access Journals (Sweden)

Alberto Barón C

Full Text Available Por lo general, el infarto del ventrículo derecho se asocia con infarto de la pared inferior del ventrículo izquierdo. La enfermedad pulmonar obstructiva crónica y la hipertrofia del ventrículo derecho, son factores que lo predisponen. Casi siempre ocurre como consecuencia de obstrucción proximal de la arteria coronaria derecha que conduce a disfunción sistólica y diastólica del ventrículo derecho. El volumen latido disminuye y el volumen diastólico y la presión de llenado del ventrículo derecho aumentan, con lo que se ocasiona hipotensión y congestión periférica. Se disminuyen el flujo sanguíneo pulmonar y el retorno venoso para el ventrículo izquierdo que puede llevar a estado de choque. Además, se pueden presentar complicaciones como bloqueo aurículo-ventricular, disfunción sinusal y aneurisma ventricular. El electrocardiograma muestra supradesnivel del ST en las derivaciones III, V1 a V3 y en V4R. El ecocardiograma muestra hipoquinesia o aquinesia de la pared libre del ventrículo derecho y hay dilatación de las cavidades derechas e insuficiencia tricúspide. El Doppler demuestra aumento en la duración de los intervalos de contracción y relajación isovolumétrica; el período eyectivo se acorta y el índice de desempeño miocárdico aumenta a valores anormales. El Doppler tisular es anormal por la disminución de la velocidad sistólica del anillo tricúspide. Una parte importante del tratamiento es optimizar el ritmo y la frecuencia cardiaca por lo que se debe evitar el uso de beta-bloqueadores; dependiendo de la severidad de la bradicardia se puede usar atropina, aminofilina o marcapasos transitorio, con la finalidad de asegurar una frecuencia adecuada. En caso de fibrilación auricular se pueden usar antiarrítmicos o cardioversión eléctrica. Se debe asegurar un adecuado volumen de llenado, para mantener la presión venosa central mayor de 15 mm Hg. El uso de vasodilatadores o diuréticos está contraindicado. Es

Dynamic Changes of QRS Morphology of Premature Ventricular Contractions During Ablation in the Right Ventricular Outflow Tract: A Case Report.

Science.gov (United States)

Yue-Chun, Li; Jia-Feng, Lin; Jia-Xuan, Lin

2015-10-01

Electrocardiographic characteristics can be useful in differentiating between right ventricular outflow tract (RVOT) and aortic sinus cusp (ASC) ventricular arrhythmias. Ventricular arrhythmias originating from ASC, however, show preferential conduction to RVOT that may render the algorithms of electrocardiographic characteristics less reliable. Even though there are few reports describing ventricular arrhythmias with ASC origins and endocardial breakout sites of RVOT, progressive dynamic changes in QRS morphology of the ventricular arrhythmias during ablation obtained were rare.This case report describes a patient with symptomatic premature ventricular contractions of left ASC origin presenting an electrocardiogram (ECG) characteristic of right ventricular outflow tract before ablation. Pacing at right ventricular outflow tract reproduced an excellent pace map. When radiofrequency catheter ablation was applied to the right ventricular outflow tract, the QRS morphology of premature ventricular contractions progressively changed from ECG characteristics of right ventricular outflow tract origin to ECG characteristics of left ASC origin.Successful radiofrequency catheter ablation was achieved at the site of the earliest ventricular activation in the left ASC. The distance between the successful ablation site of the left ASC and the site with an excellent pace map of the RVOT was 20 mm.The ndings could be strong evidence for a preferential conduction via the myocardial bers from the ASC origin to the breakout site in the right ventricular outflow tract. This case demonstrates that ventricular arrhythmias with a single origin and exit shift may exhibit QRS morphology changes.

Accuracy of fuel motion measurements using in-core detectors

International Nuclear Information System (INIS)

Dupree, S.A.

1975-01-01

An initial assessment has been made as to how accurately fuel motion can be measured with in-core detectors. A portion of this assessment has involved the calculation of the response of various detectors to fuel motion and the development of a formalism for correlating uncertainties in a neutron flux measurement to uncertainties in the fuel motion. Initially, four idealized configurations were studied in one dimension. These configurations consisted of (1) a single fuel-pin test using ACPR, (2) a seven fuel-pin test using ACPR, (3) a full subassembly (271 pin) test using a Class I ANL-type SAREF, and (4) a full subassembly plus six partial subassemblies (approximately 1000 pin) test using a Class III GE-type SAREF. It was assumed that melt would occur symmetrically at the center of the test fuel and that fuel would therefore disappear from the center of the geometry. For each case of series of calculations was performed in which detector responses were determined at several radial locations for the unperturbed core and for the core with various fractions of the fuel replaced with Na. This fuel loss was assumed to occur essentially instantaneously such that the power level in the remaining portion of the test fuel remained unchanged from that of the initial unperturbed condition

Arrhythmogenic right ventricular dysplasia: MRI findings

International Nuclear Information System (INIS)

Wall, E.E. van der; Bootsma, M.M.; Schalij, M.J.; Kayser, H.W.M.; Roos, A. de

2000-01-01

Arrhythmogenic right ventricular dysplasia (ARVD) is a heart muscle disorder of unknown cause that is characterized pathologically by fibrofatty replacement of the right ventricular myocardium. Clinical manifestations include structural and functional malformations of the right ventricle, electrocardiographic abnormalities, and presentation with ventricular tachycardias with left bundle branch pattern or sudden death. The disease is often familial with an autosomal inheritance. In addition to right ventricular dilatation, right ventricular aneurysms are typical deformities of ARVD and they are distributed in the so-called ''triangle of dysplasia'', i. e., right ventricular outflow tract, apex, and infundibulum. Ventricular aneurysms at these sites can be considered pathognomonic of ARVD. Another typical hallmark of ARVD is fibrofatty infiltration of the right ventricular free wall. These functional and morphologic characteristics are relevant to clinical imaging investigations such as contrast angiography, echocardiography, radionuclide angiography, ultrafast computed tomography, and magnetic resonance imaging (MRI). Among these techniques, MRI allows the clearest visualization of the heart, in particular because the right ventricle is involved, which is usually more difficult to explore with the other imaging modalities. Furthermore, MRI offers the specific advantage of visualizing adipose infiltration as a bright signal of the right ventricular myocardium. MRI provides the most important anatomic, functional, and morphologic criteria for diagnosis of ARVD within one single study. As a result, MRI appears to be the optimal imaging technique for detecting and following patients with clinical suspicion of ARVD. (orig.) [de

Left ventricular function in right ventricular overload

International Nuclear Information System (INIS)

Iwanaga, Shiro; Handa, Shunnosuke; Abe, Sumihisa; Onishi, Shohei; Nakamura, Yoshiro; Kunieda, Etsuo; Ogawa, Koichi; Kubo, Atsushi

1989-01-01

This study clarified regional and global functions of the distorted left ventricle due to right ventricular overload by gated radionuclide ventriculography (RNV). Cardiac catheterization and RNV were performed in 13 cases of atrial septal defect (ASD), 13 of pure mitral stenosis (MS), 10 of primary pulmonary hypertension (PPH), and 10 of normal subjects (NL). Right ventricular systolic pressure (RVSP) was 32.9±13.9, 45.0±12.2, 88.3±17.1, and 21.2±4.5 mmHg, respectively. The end-systolic LAO view of the left ventricle was halved into septal and free-wall sides. The end-diastolic halves were determined in the same plane. Ejection fractions of the global left ventricle (LVEF), global right ventricle (RVEF), the septal half of the left ventricle (SEPEF), and the free-wall half of the left ventricle (FWEF) were obtained. LVEF was 56.8±9.8% in NL, 52.8±10.5% in ASD, and 49.5±12.9% in PPH. In MS, LVEF (47.0±13.0%) was smaller than those in the other groups. RVEF was 37.0±5.2% in NL, 43.7±15.5% in ASD, and 32.8±11.5% in MS. In PPH, RVEF (25.0±10.6%) was smaller than those in the other groups. SEPEF was smaller in ASD (42.5±13.2%), MS (40.4±13.1%), PPH (40.5±12.5%) than in NL (53.5±8.5%). Systolic function of the septal half of the left ventricle was disturbed by right ventricular overload. RVEF (r=-0.35, p<0.05) and SEPEF (r=-0.51, p<0.01) had negative correlations with RVSP. As RVSP rose, systolic function of the septal half of the left ventricle was more severely disturbed. FWEF was the same among the four groups; NL (57.0±12.6%), ASD (48.6±15.2%), MS (50.5±12.0%), and PPH (51.1±12.3%). There was a good correlation between SEPEF and LVEF in NL (r=0.81), although in PPH this correlation was poor (r=0.64). These data showed that the distorted left ventricular due to right ventricular overload maintains its global function with preserved function of the free-wall side. (J.P.N.)

Summary on the activity of AERs Working Group on core monitoring (flux reconstruction, in-core measurements)

International Nuclear Information System (INIS)

Nemes, I.

2010-01-01

Working Group C had a joint meeting with Group G in Balatonfuered, Hungary, 31 May-1 June, 2010. At the joint meeting 21 people from 10 AER member organisations of 4 countries - such as Russia, Czech Republic, Slovakia and Hungary - participated. In the 2 days of the program 15 papers were presented, 10 from these connected to the topic of working group C. The title of papers and the list of participants are attached. At the meeting the following topics were discussed:1-Gd fuel introduction and experiences;2-Reactor physical measurement and evaluation problems; 3-Code development and testing;4-In-core surveillance system developments. (Author)

Efeitos hemodinâmicos da sobrecarga ventricular direita aguda experimental

Directory of Open Access Journals (Sweden)

Flávio Brito Filho

2011-04-01

Full Text Available FUNDAMENTO: A sobrecarga ventricular direita aguda está associada a situações clínicas de elevada morbimortalidade, tais como: ressecções pulmonares extensas, tromboembolismo pulmonar, transplante pulmonar e edema pulmonar das altitudes. Alguns pontos de sua fisiopatologia permanecem obscuros. OBJETIVO: Avaliar os efeitos hemodinâmicos da sobrecarga ventricular direita aguda experimental em suínos. MÉTODOS: A sobrecarga ventricular direita foi induzida pela oclusão das artérias pulmonares através de ligaduras. Vinte porcos foram utilizados no estudo, sendo alocados em 04 grupos: um controle, não submetido à oclusão vascular pulmonar, e três de sobrecarga ventricular direita submetidos à oclusão das seguintes artérias pulmonares: SVD1 (artéria pulmonar esquerda; SVD2 (artéria pulmonar esquerda e do lobo inferior direito e SVD3 (artéria pulmonar esquerda, do lobo inferior direito e do lobo mediastinal, obstruindo a vasculatura pulmonar em 42, 76 e 82,0% respectivamente. Variáveis de hemodinâmica foram medidas a cada 15 minutos durante a uma hora do estudo. Na análise estatística, foram utilizados ajustes de modelos lineares mistos com estrutura de variâncias e covariâncias. RESULTADOS: Nas comparações intergrupais, houve aumento significativo da frequência cardíaca (p = 0,004, pressão arterial pulmonar média (p = 0,001 e pressão capilar pulmonar (p < 0,0001. Houve redução significativa da pressão arterial média (p = 0,01 e do índice sistólico (p = 0,002. Não houve diferença significativa no índice cardíaco (p = 0,94. CONCLUSÃO: Apesar da intensa sobrecarga ventricular direita promovida pela obstrução de 82,0% da vasculatura pulmonar e pelo aumento significativo da pressão arterial pulmonar não houve disfunção cardiovascular severa e/ou choque circulatório no período estudado.

Fisiopatogenia y diagnóstico de la ventriculitis asociada a drenaje ventricular externo. Análisis de la formación de biopelículas bacterianas sobre el drenaje ventricular externo. Utilidad del sTREM-1 en el diagnóstico de la ventriculitis asociada a drenaje ventricular externo.

OpenAIRE

Gordón Sahuquillo, Mónica

2015-01-01

[spa] INTRODUCCIÓN: La ventriculitis asociada a drenaje ventricular externo (DVE) es una grave complicación relacionada con el uso de estos dispositivos. La formación de biopelícula sobre la superficie del DVE es un factor etiopatogénico importante pero nunca ha sido estudiado de forma sistemática. Por otra parte, establecer el diagnóstico de ventriculitis puede resultar complicado en el paciente crítico. Biomarcadores de infección como la forma soluble del triggering receptor expresse...

Impact of ventricular geometric pattern on cardiac remodeling after myocardial infarction

OpenAIRE

Farah, Elaine; Fusco, Daniéliso R.; Okumoto, Paulo R. R.; Minicucci, Marcos F.; Azevedo, Paula S.; Matsubara, Beatriz B.; Okoshi, Katashi; Zanati, Siméia G.; Paiva, Sergio A. R.; Zornoff, Leonardo A. M.

2013-01-01

FUNDAMENTO: A relevância do padrão de geometria após o infarto do miocárdio não é conhecida. OBJETIVOS: Analisar a presença de diferentes padrões de geometria ventricular esquerda (VE) e seu impacto como preditor de remodelação em pacientes com infarto do miocárdio. MÉTODOS: Pacientes com infarto agudo anterior (n = 80) foram divididos de acordo com o padrão de geometria: normal (índice de massa [IMVE] normal e espessura relativa da parede [ERP] normal), remodelação concêntrica (IMVE normal e...

Measurement of ventricular function using Doppler ultrasound

International Nuclear Information System (INIS)

Teague, S.M.

1986-01-01

Doppler has wide application in the evaluation of valvular heart disease. The need to know ventricular function is a much more common reason for an echocardiographic evaluation. Interestingly, Doppler examinations can assess ventricular function from many perspectives. Description of ventricular function entails measurement of the timing, rate and volume of ventricular filling and ejection. Doppler ultrasound examination reveals all of these aspects of ventricular function noninvasively, simply, and without great expense or radiation exposure, as described in this chapter

Right ventricular function in patients with ischemic heart disease

International Nuclear Information System (INIS)

Araki, Haruo; Hisano, Ryuichi; Nagata, Yoshiyuki; Caglar, N.; Nakamura, Motoomi

1985-01-01

Thirty-five patients with ischemic heart disease (IHD) and 10 normal subjects were studied. Right and left ventricular ejecction fractions (EF) were determined using equilibrium radionuclide ventriculography with technetium-99m. Furthermore, abnormal motion of the right ventricular septal wall was obtained by cardiac cathetelization, and its relation to the right ventricular EF was examined. In IHD patients with anterior myocardial infarction, left ventricular EF decreased, but right ventricular EF was normal. This suggested that left ventricular dysfunction does not always have an effect on right ventricular function. Right ventricular EF was normal even when akinesis or dyskinesis was present in the ventricular septul, suggesting that abnormal motion of the ventricular septal wall has no significantly stimulant effect on right ventricular function. A decreased right ventricular EF was likely to occur only when the right ventricular free wall became ischemic or necrotic simultaneously with occurrence of posterior myocardial infarction. (Namekawa, K.)

A nuclear heuristic for application to metaheuristics in-core fuel management optimization

Energy Technology Data Exchange (ETDEWEB)

Meneses, Anderson Alvarenga de Moura, E-mail: ameneses@lmp.ufrj.b [COPPE/Federal University of Rio de Janeiro, RJ (Brazil). Nuclear Engineering Program; Dalle Molle Institute for Artificial Intelligence (IDSIA), Manno-Lugano, TI (Switzerland); Gambardella, Luca Maria, E-mail: luca@idsia.c [Dalle Molle Institute for Artificial Intelligence (IDSIA), Manno-Lugano, TI (Switzerland); Schirru, Roberto, E-mail: schirru@lmp.ufrj.b [COPPE/Federal University of Rio de Janeiro, RJ (Brazil). Nuclear Engineering Program

2009-07-01

The In-Core Fuel Management Optimization (ICFMO) is a well-known problem of nuclear engineering whose features are complexity, high number of feasible solutions, and a complex evaluation process with high computational cost, thus it is prohibitive to have a great number of evaluations during an optimization process. Heuristics are criteria or principles for deciding which among several alternative courses of action are more effective with respect to some goal. In this paper, we propose a new approach for the use of relational heuristics for the search in the ICFMO. The Heuristic is based on the reactivity of the fuel assemblies and their position into the reactor core. It was applied to random search, resulting in less computational effort concerning the number of evaluations of loading patterns during the search. The experiments demonstrate that it is possible to achieve results comparable to results in the literature, for future application to metaheuristics in the ICFMO. (author)

A nuclear heuristic for application to metaheuristics in-core fuel management optimization

International Nuclear Information System (INIS)

Meneses, Anderson Alvarenga de Moura; Gambardella, Luca Maria; Schirru, Roberto

2009-01-01

The In-Core Fuel Management Optimization (ICFMO) is a well-known problem of nuclear engineering whose features are complexity, high number of feasible solutions, and a complex evaluation process with high computational cost, thus it is prohibitive to have a great number of evaluations during an optimization process. Heuristics are criteria or principles for deciding which among several alternative courses of action are more effective with respect to some goal. In this paper, we propose a new approach for the use of relational heuristics for the search in the ICFMO. The Heuristic is based on the reactivity of the fuel assemblies and their position into the reactor core. It was applied to random search, resulting in less computational effort concerning the number of evaluations of loading patterns during the search. The experiments demonstrate that it is possible to achieve results comparable to results in the literature, for future application to metaheuristics in the ICFMO. (author)

ZAKI: a windows-based ko standardization code for in-core INAA

International Nuclear Information System (INIS)

Ojo, J.O.; Filby, R.H.

2002-01-01

A new computer code ZAKI, for k o -based INAA standardization, written in Visual Basic for the WINDOWS environment is described. The parameter α measuring the deviation of the epithermal neutron spectrum shape from the ideal 1/E shape, and the thermal-to-epithermal flux ratio f, are monitored at each irradiation position for each irradiation using the ''triple bare monitor with k o '' technique. Stability of the irradiation position with respect to α and f is therefore assumed only for the duration of the irradiation. This now makes it possible to use k o standardization even for in-core reactor irradiation channels without an a priori knowledge of α and f values as required by existing commercial software. ZAKI is considerably versatile and contains features which allow for use of several detectors at different counting geometries, direct inputting of peak search output from GeniePc, and automatic nuclide identification of all gamma lines using an in-built library. Sample results for two certified reference materials are presented

Right ventricular failure after implantation of a continuous-flow left ventricular assist device

DEFF Research Database (Denmark)

Cordtz, Johan Joakim; Nilsson, Jens C; Hansen, Peter B

2014-01-01

Right ventricular failure (RVF) is a significant complication after implantation of a left ventricular assist device. We aimed to identify haemodynamic changes in the early postoperative phase that predicted subsequent development of RVF in a cohort of HeartMate II (HMII) implanted patients....

Ventricular fibrillation in an ambulatory patient supported by a left ventricular assist device: highlighting the ICD controversy.

Science.gov (United States)

Boilson, Barry A; Durham, Lucian A; Park, Soon J

2012-01-01

Left ventricular assist devices (LVADs) provide an effective means of managing advanced pump failure as a means of bridging to cardiac transplantation or as permanent therapy. Although ventricular arrhythmias remain common post-LVAD implantation, such therapy may allow malignant arrhythmias to be tolerated hemodynamically. This report describes the clinical findings in a patient who had likely been in a ventricular tachyarrhythmia for several days and presented in ventricular fibrillation, ambulatory, and mentating normally. This report, with previous similar reports, is additive to the body of evidence that LVADs alter the physiologic impact of ventricular arrhythmias in advanced heart failure and highlights the need for thoughtful programming of implantable cardioverter defibrillator therapies in these patients.

Action potential conduction between a ventricular cell model and an isolated ventricular cell

NARCIS (Netherlands)

Wilders, R.; Kumar, R.; Joyner, R. W.; Jongsma, H. J.; Verheijck, E. E.; Golod, D.; van Ginneken, A. C.; Goolsby, W. N.

1996-01-01

We used the Luo and Rudy (LR) mathematical model of the guinea pig ventricular cell coupled to experimentally recorded guinea pig ventricular cells to investigate the effects of geometrical asymmetry on action potential propagation. The overall correspondence of the LR cell model with the recorded

Development of an inconel self powered neutron detector for in-core reactor monitoring

Science.gov (United States)

Alex, M.; Ghodgaonkar, M. D.

2007-04-01

The paper describes the development and testing of an Inconel600 (2 mm diameter×21 cm long) self-powered neutron detector for in-core neutron monitoring. The detector has 3.5 mm overall diameter and 22 cm length and is integrally coupled to a 12 m long mineral insulated cable. The performance of the detector was compared with cobalt and platinum detectors of similar dimensions. Gamma sensitivity measurements performed at the 60Co irradiation facility in 14 MR/h gamma field showed values of -4.4×10 -18 A/R/h/cm (-9.3×10 -24 A/ γ/cm 2-s/cm), -5.2×10 -18 A/R/h/cm (-1.133×10 -23 A/ γ/cm 2-s/cm) and 34×10 -18 A/R/h/cm (7.14×10 -23 A/ γ/cm 2-s/cm) for the Inconel, Co and Pt detectors, respectively. The detectors together with a miniature gamma ion chamber and fission chamber were tested in the in-core Apsara Swimming Pool type reactor. The ion chambers were used to estimate the neutron and gamma fields. With an effective neutron cross-section of 4b, the Inconel detector has a total sensitivity of 6×10 -23 A/nv/cm while the corresponding sensitivities for the platinum and cobalt detectors were 1.69×10 -22 and 2.64×10 -22 A/nv/cm. The linearity of the detector responses at power levels ranging from 100 to 200 kW was within ±5%. The response of the detectors to reactor scram showed that the prompt response of the Inconel detector was 0.95 while it was 0.7 and 0.95 for the platinum and cobalt self-powered detectors, respectively. The detector was also installed in the horizontal flux unit of 540 MW Pressurised Heavy Water Reactor (PHWR). The neutron flux at the detector location was calculated by Triveni code. The detector response was measured from 0.02% to 0.07% of full power and showed good correlation between power level and detector signals. Long-term tests and the dynamic response of the detector to shut down in PHWR are in progress.

Development of an inconel self powered neutron detector for in-core reactor monitoring

International Nuclear Information System (INIS)

Alex, M.; Ghodgaonkar, M.D.

2007-01-01

The paper describes the development and testing of an Inconel600 (2 mm diameterx21 cm long) self-powered neutron detector for in-core neutron monitoring. The detector has 3.5 mm overall diameter and 22 cm length and is integrally coupled to a 12 m long mineral insulated cable. The performance of the detector was compared with cobalt and platinum detectors of similar dimensions. Gamma sensitivity measurements performed at the 60 Co irradiation facility in 14 MR/h gamma field showed values of -4.4x10 -18 A/R/h/cm (-9.3x10 -24 A/γ/cm 2 -s/cm), -5.2x10 -18 A/R/h/cm (-1.133x10 -23 A/γ/cm 2 -s/cm) and 34x10 -18 A/R/h/cm (7.14x10 -23 A/γ/cm 2 -s/cm) for the Inconel, Co and Pt detectors, respectively. The detectors together with a miniature gamma ion chamber and fission chamber were tested in the in-core Apsara Swimming Pool type reactor. The ion chambers were used to estimate the neutron and gamma fields. With an effective neutron cross-section of 4b, the Inconel detector has a total sensitivity of 6x10 -23 A/nv/cm while the corresponding sensitivities for the platinum and cobalt detectors were 1.69x10 -22 and 2.64x10 -22 A/nv/cm. The linearity of the detector responses at power levels ranging from 100 to 200 kW was within ±5%. The response of the detectors to reactor scram showed that the prompt response of the Inconel detector was 0.95 while it was 0.7 and 0.95 for the platinum and cobalt self-powered detectors, respectively. The detector was also installed in the horizontal flux unit of 540 MW Pressurised Heavy Water Reactor (PHWR). The neutron flux at the detector location was calculated by Triveni code. The detector response was measured from 0.02% to 0.07% of full power and showed good correlation between power level and detector signals. Long-term tests and the dynamic response of the detector to shut down in PHWR are in progress

Development of discrete-time H∞ filtering method for time-delay compensation of rhodium incore detectors

International Nuclear Information System (INIS)

Park, Moon Kyu; Kim, Yong Hee; Cha, Kune Ho; Kim, Myung Ki

1998-01-01

A method is described to develop an H∞ filtering method for the dynamic compensation of self-powered neutron detectors normally used for fixed incore instruments. An H∞ norm of the filter transfer matrix is used as the optimization criteria in the worst-case estimation error sense. Filter modeling is performed for discrete-time model. The filter gains are optimized in the sense of noise attenuation level of H∞ setting. By introducing Bounded Real Lemma, the conventional algebraic Riccati inequalities are converted into Linear Matrix Inequalities (LMIs). Finally, the filter design problem is solved via the convex optimization framework using LMIs. The simulation results show that remarkable improvements are achieved in view of the filter response time and the filter design efficiency

The helical ventricular myocardial band: global, three-dimensional, functional architecture of the ventricular myocardium.

Science.gov (United States)

Kocica, Mladen J; Corno, Antonio F; Carreras-Costa, Francesc; Ballester-Rodes, Manel; Moghbel, Mark C; Cueva, Clotario N C; Lackovic, Vesna; Kanjuh, Vladimir I; Torrent-Guasp, Francisco

2006-04-01

We are currently witnessing the advent of new diagnostic tools and therapies for heart diseases, but, without serious scientific consensus on fundamental questions about normal and diseased heart structure and function. During the last decade, three successive, international, multidisciplinary symposia were organized in order to setup fundamental research principles, which would allow us to make a significant step forward in understanding heart structure and function. Helical ventricular myocardial band of Torrent-Guasp is the revolutionary new concept in understanding global, three-dimensional, functional architecture of the ventricular myocardium. This concept defines the principal, cumulative vectors, integrating the tissue architecture (i.e. form) and net forces developed (i.e. function) within the ventricular mass. Here we expose the compendium of Torrent-Guasp's half-century long functional anatomical investigations in the light of ongoing efforts to define the integrative approach, which would lead to new understanding of the ventricular form and function by linking across multiple scales of biological organization, as defined in ongoing Physiome project. Helical ventricular myocardial band of Torrent-Guasp may also, hopefully, allow overcoming some difficulties encountered in contemporary efforts to create a comprehensive mathematical model of the heart.

On-power verification of the dynamic response of self-powered in-core detectors

International Nuclear Information System (INIS)

Serdula, K.; Beaudet, M.

1996-01-01

Self-powered in-core detectors are used for on-line safety and regulation purposes in CANDU reactors. Such applications require use of detectors whose response is primarily prompt to changes in flux. In-service verification of the detectors' response is required to ensure significant degradation in performance has not occurred during long-term operation. Changes in the detector characteristics occur due to nuclear interactions and failures. Present verification requires significant station resources and disrupts power production. Use of the 'noise' in the detector signal is being investigated as an alternative to assess the dynamic response of the detectors during long-term operation. Measurements of reference 'signatures' were obtained from replacement shutdown system detectors. Results show 'noise' measurements are a promising alternative to the current verification method. Identification of changes in the detector response function assist in accurate diagnosis and prognosis of changes in detector signals due to process changes. (author)

Application of radionuclide ventriculography phase analysis in patients with atrial or ventricular pacing for detecting ventricular abnormal excitation

International Nuclear Information System (INIS)

Shi Rongfang; Wang Zhonggan; Li Shengting

1996-01-01

The aim of the study was to increase the accuracy of detecting ventricular abnormal excitation. During atrial or ventricular pacing, radionuclide ventriculography phase analysis (RNV-PA) was performed in 17 patients with Wolff-Parkinson-White (W-P-W) syndrome and paroxysmal supra ventricular tachycardia (PSVT) and ventricular tachycardia (PVT). During pacing, detection rate of abnormal excitation by RNV-PA was 95.5%, compared with 68.2% during basic conduction. Atrial or ventricular pacing can significantly increase the detection rate of abnormal excitation by RNV-PA in patients with W-P-W syndrome. It may be a valuable method for identifying the abnormal excitation and estimating the therapeutic effect of ablation

A fixed incore based system for an on line core margin monitoring

International Nuclear Information System (INIS)

Mourlevat, J. L.; Carrasco, M.

2002-01-01

FRAMATOME-ANP has developed a new core monitoring system which is based on measurements coming from fixed incore sensors and on a 3D power distribution on line reconstruction. After selecting the rhodium self powered neutron detectors as fixed incore sensors, a first step of this development consisted in testing this kind of sensors in the French Golfech Unit 2 reactor (4L, 1300 MWe). (Author)

Effect of right ventricular electrode location (outflow tract vs. apex) on mechanical Ventricular synchrony in patients that underwent pacemaker implant therapy

International Nuclear Information System (INIS)

Rincon, Oscar S; Saenz, Luis C; Salazar, Gabriel; Hernandez, Edgar

2008-01-01

Objective: to assess in depth the effect of ventricular stimulation from the right ventricular outflow tract and the apex on mechanical ventricular synchrony. Materials And Methods: cohort analytical study. 20 patients with indication of definitive pacemaker indication underwent trans thoracic echocardiogram before and after pacemaker implant with electrode implantation in the right ventricular outflow tract and in the apex (10 patients in each group). There was no structural cardiopathy, ejection fraction was ? 50%, QRS and AV conduction were normal. Mechanical ventricular asynchrony (M mode and tissue doppler) and implant and device parameters were evaluated. Statistical Analysis: results are given as mean values, standard deviation or percentages.Continuous variables were compared using Chi-square test and ANOVA. A p <0.05 value was considered statistically significant. Results: in five patients (25%) a pre-implant ventricular asynchrony was found; in seven (70%) ventricular asynchrony post-implant in the right ventricle outflow tract and in 5 (50%) in the apex. Mean interventricular pot-implant delay was 21,6 ms in the right ventricular outflow tract and 11,5 ms in the apex (p = 0,8); mean septal to lateral wall delay was 73 ms in the right ventricular outflow tract and 26 ms in the apex (p = 0,8). QRS post-implant delay was 134 ms in the right ventricular outflow tract and 140 ms in the apex (p = 0,1). No differences between implant parameters and device programming were found. Conclusions: presence of ventricular asynchrony was evidenced in patients with normal QRS and structurally healthy heart. Ventricular stimulation with pacemaker from the apex or the right ventricular outflow tract suggests acute ventricular asynchrony at least in 60% of the cases, without statistically significant difference between both groups.

First In-Core Simultaneous Measurements of Nuclear Heating and Thermal Neutron Flux Obtained With the Innovative Mobile Calorimeter CALMOS Inside the OSIRIS Reactor

Science.gov (United States)

Carcreff, Hubert; Salmon, Laurent; Bubendorff, Jacques; Lepeltier, Valérie

2016-10-01

Nuclear heating inside a MTR reactor has to be known in order to design and run irradiation experiments which have to fulfill target temperature constraints. This measurement is usually carried out by calorimetry. The innovative calorimetric system, CALMOS, has been studied and built in 2011 for the 70MWth OSIRIS reactor operated by CEA. Thanks to a new type of calorimetric probe, associated to a specific displacement system, it provides measurements along the fissile height and above the core. Calorimeter working modes, measurement procedures, main modeling and experimental results and expected advantages of this new technique have been already presented in previous papers. However, these first in-core measurements were not performed beyond 6 W · g-1, due to an inside temperature limitation imposed by a safety authority requirement. In this paper, we present the first in-core simultaneous measurements of nuclear heating and conventional thermal neutron flux obtained by the CALMOS device at 70 MW nominal reactor power. For the first time, this experimental system was operated in nominal in-core conditions, with nominal neutron flux up to 2.7 1014 n · cm-2 · s-1 and nuclear heating up to 12 W · g-1. After a brief reminder of the calorimetric cell configuration and displacement system specificities, first nuclear heating distributions at nominal power are presented and discussed. In order to reinforce the heating evaluation, a comparison is made between results obtained by the probe calibration coefficient and the zero methods. Thermal neutron flux evaluation from SPND signal processing required a specific TRIPOLI-4 Monte Carlo calculation which has been performed with the precise CALMOS cell geometry. In addition, the Finite Element model for temperatures map prediction inside the calorimetric cell has been upgraded with recent experimental data obtained up to 12 W · g-1. Finally, the experience feedback led us to improvement perspectives. A second device is

Ventricular Effective Refraction Period and Ventricular Repolarization Analysis in Experimental Tachycardiomyopathy in Swine.

Science.gov (United States)

Noszczyk-Nowak, Agnieszka; Pasławska, Urszula; Gajek, Jacek; Janiszewski, Adrian; Pasławski, Robert; Zyśko, Dorota; Nicpoń, Józef

2016-01-01

Swine are recognized animal models of human cardiovascular diseases. However, little is known on the CHF-associated changes in the electrophysiological ventricular parameters of humans and animals. The aim of this study was to analyze changes in the durations of ventricular effective refraction period (VERP), QT and QTc intervals of pigs with chronic tachycardia-induced tachycardiomyopathy (TIC). The study was comprised of 28 adult pigs (8 females and 20 males) of the Polish Large White breed. A one-chamber pacemaker was implanted in each of the 28 pigs. Electrocardiographic, echocardiographic and electrophysiological studies were carried out prior to the pacemaker implantation and at subsequent 4-week intervals. All electrocardiographic, echocardiographic and short electrophysiological study measurements in all swine were done under general anesthesia (propofol) after premedication with midazolam, medetomidine, and ketamine. No significant changes in the duration of QT interval and corrected QT interval (QTc) were observed during consecutive weeks of the experiment. The duration of the QTc interval of female pigs was shown to be significantly longer than that of the males throughout the whole study period. Beginning from the 12th week of rapid ventricular pacing, a significant increase in duration of VERP was observed in both male and female pigs. Males and females did not differ significantly in terms of VERP duration determined throughout the whole study period. Ventricular pacing, stimulation with 2 and 3 premature impulses at progressively shorter coupling intervals and an imposed rhythm of 130 bpm or 150 bpm induced transient ventricular tachycardia in one female pig and four male pigs. One episode of permanent ventricular tachycardia was observed. The number of induced arrhythmias increased proportionally to the severity of heart failure and duration of the experiment. However, relatively aggressive protocols of stimulation were required in order to induce

Ventricular arrhythmias in Chagas disease

Directory of Open Access Journals (Sweden)

Marco Paulo Tomaz Barbosa

2015-02-01

Full Text Available Sudden death is one of the most characteristic phenomena of Chagas disease, and approximately one-third of infected patients develop life-threatening heart disease, including malignant ventricular arrhythmias. Fibrotic lesions secondary to chronic cardiomyopathy produce arrhythmogenic substrates that lead to the appearance and maintenance of ventricular arrhythmias. The objective of this study is to discuss the main clinical and epidemiological aspects of ventricular arrhythmias in Chagas disease, the specific workups and treatments for these abnormalities, and the breakthroughs needed to determine a more effective approach to these arrhythmias. A literature review was performed via a search of the PubMed database from 1965 to May 31, 2014 for studies of patients with Chagas disease. Clinical management of patients with chronic Chagas disease begins with proper clinical stratification and the identification of individuals at a higher risk of sudden cardiac death. Once a patient develops malignant ventricular arrhythmia, the therapeutic approach aims to prevent the recurrence of arrhythmias and sudden cardiac death by the use of implantable cardioverter defibrillators, antiarrhythmic drugs, or both. In select cases, invasive ablation of the reentrant circuit causing tachycardia may be useful. Ventricular arrhythmias are important manifestations of Chagas cardiomyopathy. This review highlights the absence of high-quality evidence regarding the treatment of ventricular arrhythmias in Chagas disease. Recognizing high-risk patients who require specific therapies, especially invasive procedures such as the implantation of cardioverter defibrillators and ablative approaches, is a major challenge in clinical practice.

Evaluation of Right Ventricular Function with Radionuclide Cardiac Angiography - Right Ventricular Ejection Fraction in Chronic Obstructive Lung Disease

International Nuclear Information System (INIS)

Sohn, In; Shin, Sung Hae; Chung, June Key; Lee, Myung Chul; Cho, Bo Youn; Lee, Young Woo; Han, Yong Cheol; Koh, Chang Soon

1982-01-01

To evaluate the usefulness of radionuclide cardiac angiography in the assessment of the right ventricular function, we measured right ventricular ejection fraction (RVEF) using single pass method. In 12 normal persons, RVEF averaged 52.7±5.9% (mean±S.D.). In 25 patients with chronic obstructive lung disease, RVEF was 37.2±10.6% and significantly lower than that of normal person (p<0.01). All 10 patients with right ventricular failure had abnormal RVEF, which was significantly lower than that of 14 persons without right ventricular failure (27.6±5.7%, 43.9±8.5%, respectively, p<0.01). It concluded that RVEF measured by single pass radionuclide cardiac angiography was a useful, noninvasive method to assess right ventricular function.

ZAKI a windows-based k sub o standardization code for in-core INAA

CERN Document Server

Ojo, J O

2002-01-01

A new computer code ZAKI, for k sub o -based INAA standardization, written in Visual Basic for the WINDOWS environment is described. The parameter alpha measuring the deviation of the epithermal neutron spectrum shape from the ideal 1/E shape, and the thermal-to-epithermal flux ratio f, are monitored at each irradiation position for each irradiation using the ''triple bare monitor with k sub o '' technique. Stability of the irradiation position with respect to alpha and f is therefore assumed only for the duration of the irradiation. This now makes it possible to use k sub o standardization even for in-core reactor irradiation channels without an a priori knowledge of alpha and f values as required by existing commercial software. ZAKI is considerably versatile and contains features which allow for use of several detectors at different counting geometries, direct inputting of peak search output from GeniePc, and automatic nuclide identification of all gamma lines using an in-built library. Sample results for ...

INSIGHT: an integrated scoping analysis tool for in-core fuel management of PWR

International Nuclear Information System (INIS)

Yamamoto, Akio; Noda, Hidefumi; Ito, Nobuaki; Maruyama, Taiji.

1997-01-01

An integrated software tool for scoping analysis of in-core fuel management, INSIGHT, has been developed to automate the scoping analysis and to improve the fuel cycle cost using advanced optimization techniques. INSIGHT is an interactive software tool executed on UNIX based workstations that is equipped with an X-window system. INSIGHT incorporates the GALLOP loading pattern (LP) optimization module that utilizes hybrid genetic algorithms, the PATMAKER interactive LP design module, the MCA multicycle analysis module, an integrated database, and other utilities. Two benchmark problems were analyzed to confirm the key capabilities of INSIGHT: LP optimization and multicycle analysis. The first was the single cycle LP optimization problem that included various constraints. The second one was the multicycle LP optimization problem that includes the assembly burnup limitation at rod cluster control (RCC) positions. The results for these problems showed the feasibility of INSIGHT for the practical scoping analysis, whose work almost consists of LP generation and multicycle analysis. (author)

Detection of left ventricular thrombi by computerised tomography

International Nuclear Information System (INIS)

Nair, C.K.; Sketch, M.H.; Mahoney, P.D.; Lynch, J.D.; Mooss, A.N.; Kenney, N.P.

1981-01-01

Sixteen patients suspected of having left ventricular mural thrombi were studied. All had suffered transmural myocardial infarction. Fifteen patients had a ventricular aneurysm. One had had systemic emboli. The mean length of time between the myocardial infarction and the study was 14.8 months, with a range of one month to 79 months. All patients underwent computerised tomography of the heart, M-mode echocardiography (M-mode), and two-dimensional echocardiography (2-D). Eight patients underwent left ventricular cineangiography. Five patients had surgical confirmation. Computerised tomography, two-dimensional, and M-mode echocardiography predicted left ventricular mural thrombi in 10, eight, and one of the 16 patients, respectively. Left ventricular cineangiography predicted left ventricular mural thrombi in four out of eight patients. Computerised tomography and left ventricular cineangiography correctly predicted the presence or absence of left ventricular thrombi in all five patients who underwent operation. In the same group, however, two-dimensional and M-mode echocardiography failed to predict the presence of thrombi in one and three patients, respectively. Among the 11 patients without surgical confirmation, one, in whom no left ventricular thrombi were shown by M-mode and two-dimensional echocardiography, was found to have thrombi on computerised tomography. In another, two-dimensional echocardiography was positive but this finding was not confirmed either by computerised tomography or by left ventricular angiography. (author)

Arrhythmogenic right ventricular dysplasia

International Nuclear Information System (INIS)

Vignolo Puglia, W.; Freire Colla, D.; Rivara Urrutia, D.; Lujambio Grene, M.; Arbiza Bruno, T.; Oliveira, G.; Cobas Rodriguez, J.

1997-01-01

The arrhythmogenic right ventricular dysplasia is a condition predominantly well defined with arrhythmic events. We analyze three cases diagnosed by the group. These cases were presented as ventricular tachycardia with a morphology of left bundle branch block, presenting one of them aborted sudden death in evolution. The baseline electrocardiogram and signal averaging were abnormal in two of the three cases, like the echocardiogram. The electrophysiological study was able to induce in the three patients with sustained monomorphic ventricular tachycardia morphology of left bundle branch block. The definitive diagnosis was made by right ventriculography in two cases and magnetic resonance imaging in the other. Treatment included antiarrhythmic drugs in the three cases and the placement of an automatic defibrillator which survived a sudden death (Author)

Isolated left ventricular non-compaction cardiomyopathy associated with polymorphous ventricular tachycardia mimicking torsades de pointes

Directory of Open Access Journals (Sweden)

Oana Dickinson

2013-02-01

Full Text Available Left ventricular non-compaction (LVNC cardiomyopathy is a rare congenital disorder, classified by the American Heart Association as a primary genetic cardiomyopathy and characterized by multiple trabeculations within the left ventricle. LVNC cardiomyopathy has been associated with 3 major clinical manifestations: heart failure, atrial and ventricular arrhythmias and thromboembolic events, including stroke. In this case report, we describe a female patient with apparently isolated LVNC in whom pause-dependent polymorphic ventricular tachycardia suggesting torsades de pointes occurred in the presence of a normal QT interval.

Two-dimensional echocardiographic features of right ventricular infarction

International Nuclear Information System (INIS)

D'Arcy, B.; Nanda, N.C.

1982-01-01

Real-time, two-dimensional echocardiographic studies were performed in 10 patients with acute myocardial infarction who had clinical features suggestive of right ventricular involvement. All patients showed right ventricular wall motion abnormalities. In the four-chamber view, seven patients showed akinesis of the entire right ventricular diaphragmatic wall and three showed akinesis of segments of the diaphragmatic wall. Segmental dyskinetic areas involving the right ventricular free wall were identified in four patients. One patient showed a large right ventricular apical aneurysm. Other echocardiographic features included enlargement of the right ventricle in eight cases, paradoxical ventricular septal motion in seven cases, tricuspid incompetence in eight cases, dilation of the stomach in four cases and localized pericardial effusion in two cases. Right ventricular infarction was confirmed by radionuclide methods in seven patients, at surgery in one patient and at autopsy in two patients

Method and device for monitoring vibration of incore neutron detector guide tube

International Nuclear Information System (INIS)

Enomoto, Mitsuhiro; Naito, Norio; Oda, Akira.

1978-01-01

Purpose: To easily detect the vibration of an incore neutron detector guide tube and to prevent the occurrence of such accidents that the guide tube comes into contact with the fuel channel box arranged around the periphery thereof to break the channel box. Method: A neutron detector guide tube is disposed within a channel box, and the neutron detector is arranged at the center of the guide tube. Now, when the guide tube vibrates at an inherent number of vibration and a predetermined amplitude, the guide tube moves in the radial direction by the predetermined amplitude part to come into contact with the channel box. Upon this occasion, the detector similarity vibrates, and the output signal is varied by the predetermined neutron flux variation part. This output signal is sent to a comparator through an analyser, and compared with the output signal produced from a device wherein the result analysed at normal time, and the output signal is sent to an alarm device and an indicator, respectively. (Aizawa, K.)

In-core neutron flux measurements at PARR using self powered neutron detector

International Nuclear Information System (INIS)

Hussain, A.; Ansari, S.A.

1989-10-01

This report describes experimental reactor physics measure ments at PARR using the in-core neutron detectors. Rhodium self powered neutron detectors (SPND) were used in the PARR core and several measurements were made aimed at detector calibration, response time determination and neutron flux measurements. The detectors were calibrated at low power using gold foils and full power by the thermal channel. Based on this calibration it was observed that the detector response remains almost linear throughout the power range. The self powered detectors were used for on-line determination of absolute neutron flux in the core as well as the spatial distribution of neutron flux or reactor power. The experimental, axial and horizontal flux mapping results at certain locations in the core are presented. The total response time of rhodium detector was experimentally determined to be about 5 minutes, which agree well with the theoretical results. Because of longer response time of SPND of the detectors it is not possible to use them in the reactor protection system. (author). 10 figs

Study on in-core fuel management for CNP1500 nuclear power plant

International Nuclear Information System (INIS)

Li Dongsheng

2005-10-01

CNP1500 is a four-loop PWR nuclear power plant with light water as moderator and coolant. The reactor core is composed of 205 AFA-3GXL fuel assemblies. The active core height at cold is 426.4 cm and equivalent diameter is 347.0 cm. The reactor thermal output is 4250 MW, and average linear power density is 179.5 W/cm. The cycle length of equilibrium cycle core is 470 equivalent full power days. For all cycles, the moderator temperature coefficients at all conditions are negative values, the nuclear enthalpy rise factors F ΔH at hot full power, all control rods out and equilibrium xenon are less than the limit value, the maximum discharge assembly burnup is less 55000 MW·d/tU, and the shutdown margin values at the end of life meet design criteria. The low-leakage core loading reduces radiation damage on pressure vessel and is beneficial to prolong use lifetime of it. The in-core fuel management design scheme and main calculation results for CNP1500 nuclear power plant are presented. (author)

Monitoring the mechanical vibration of in-core detector tubes and fuel channels via ICFD noise analysis

International Nuclear Information System (INIS)

Glockler, O.; Cooke, D.F.; Czuppon, G.J.; Kapoor, K.K.

2000-01-01

Vibrations of core internals are regularly monitored in the CANDU nuclear generating stations of Ontario Power Generation (OPG) via the noise analysis of in-core flux detectors (ICFDs). Voltage signals of standard station instrumentation are recorded by portable multi-channel high-speed high-resolution data acquisition systems, then statistical parameters are derived from the multi-channel time series measurements. Reactor noise analysis is a non-intrusive statistical technique regularly used in system surveillance, diagnostics and in actual operational I and C problems. It utilizes the dynamic information carried by the small fluctuations (noise) of station signals measured around their mean values during steady-state operation. The present paper discusses specific results related to the flow-induced mechanical vibrations of detector tubes and fuel channels. (author)

Exercise thallium testing in ventricular preexcitation

Energy Technology Data Exchange (ETDEWEB)

Archer, S.; Gornick, C.; Grund, F.; Shafer, R.; Weir, E.K.

1987-05-01

Ventricular preexcitation, as seen in Wolff-Parkinson-White syndrome, results in a high frequency of positive exercise electrocardiographic responses. Why this occurs is unknown but is not believed to reflect myocardial ischemia. Exercise thallium testing is often used for noninvasive assessment of coronary artery disease in patients with conditions known to result in false-positive electrocardiographic responses. To assess the effects of ventricular preexcitation on exercise thallium testing, 8 men (aged 42 +/- 4 years) with this finding were studied. No subject had signs or symptoms of coronary artery disease. Subjects exercised on a bicycle ergometer to a double product of 26,000 +/- 2,000 (+/- standard error of mean). All but one of the subjects had at least 1 mm of ST-segment depression. Tests were terminated because of fatigue or dyspnea and no patient had chest pain. Thallium test results were abnormal in 5 patients, 2 of whom had stress defects as well as abnormally delayed thallium washout. One of these subjects had normal coronary arteries on angiography with a negative ergonovine challenge, and both had normal exercise radionuclide ventriculographic studies. Delayed thallium washout was noted in 3 of the subjects with ventricular preexcitation and normal stress images. This study suggests that exercise thallium testing is frequently abnormal in subjects with ventricular preexcitation. Ventricular preexcitation may cause dyssynergy of ventricular activation, which could alter myocardial thallium handling, much as occurs with left bundle branch block. Exercise radionuclide ventriculography may be a better test for noninvasive assessment of coronary artery disease in patients with ventricular preexcitation.

Exercise thallium testing in ventricular preexcitation

International Nuclear Information System (INIS)

Archer, S.; Gornick, C.; Grund, F.; Shafer, R.; Weir, E.K.

1987-01-01

Ventricular preexcitation, as seen in Wolff-Parkinson-White syndrome, results in a high frequency of positive exercise electrocardiographic responses. Why this occurs is unknown but is not believed to reflect myocardial ischemia. Exercise thallium testing is often used for noninvasive assessment of coronary artery disease in patients with conditions known to result in false-positive electrocardiographic responses. To assess the effects of ventricular preexcitation on exercise thallium testing, 8 men (aged 42 +/- 4 years) with this finding were studied. No subject had signs or symptoms of coronary artery disease. Subjects exercised on a bicycle ergometer to a double product of 26,000 +/- 2,000 (+/- standard error of mean). All but one of the subjects had at least 1 mm of ST-segment depression. Tests were terminated because of fatigue or dyspnea and no patient had chest pain. Thallium test results were abnormal in 5 patients, 2 of whom had stress defects as well as abnormally delayed thallium washout. One of these subjects had normal coronary arteries on angiography with a negative ergonovine challenge, and both had normal exercise radionuclide ventriculographic studies. Delayed thallium washout was noted in 3 of the subjects with ventricular preexcitation and normal stress images. This study suggests that exercise thallium testing is frequently abnormal in subjects with ventricular preexcitation. Ventricular preexcitation may cause dyssynergy of ventricular activation, which could alter myocardial thallium handling, much as occurs with left bundle branch block. Exercise radionuclide ventriculography may be a better test for noninvasive assessment of coronary artery disease in patients with ventricular preexcitation

Linear variable differential transformer and its uses for in-core fuel rod behavior measurements

International Nuclear Information System (INIS)

Wolf, J.R.

1979-01-01

The linear variable differential transformer (LVDT) is an electromechanical transducer which produces an ac voltage proportional to the displacement of a movable ferromagnetic core. When the core is connected to the cladding of a nuclear fuel rod, it is capable of producing extremely accurate measurements of fuel rod elongation caused by thermal expansion. The LVDT is used in the Thermal Fuels Behavior Program at the U.S. Idaho National Engineering Laboratory (INEL) for measurements of nuclear fuel rod elongation and as an indication of critical heat flux and the occurrence of departure from nucleate boiling. These types of measurements provide important information about the behavior of nuclear fuel rods under normal and abnormal operating conditions. The objective of the paper is to provide a complete account of recent advances made in LVDT design and experimental data from in-core nuclear reactor tests which use the LVDT

Idiopathic ventricular tachycardia and fibrillation.

Science.gov (United States)

Belhassen, B; Viskin, S

1993-06-01

Important data have recently been added to our understanding of sustained ventricular tachyarrhythmias occurring in the absence of demonstrable heart disease. Idiopathic ventricular tachycardia (VT) is usually of monomorphic configuration and can be classified according to its site of origin as either right monomorphic (70% of all idiopathic VTs) or left monomorphic VT. Several physiopathological types of monomorphic VT can be presently individualized, according to their mode of presentation, their relationship to adrenergic stress, or their response to various drugs. The long-term prognosis is usually good. Idiopathic polymorphic VT is a much rarer type of arrhythmia with a less favorable prognosis. Idiopathic ventricular fibrillation may represent an underestimated cause of sudden cardiac death in ostensibly healty patients. A high incidence of inducibility of sustained polymorphic VT with programmed ventricular stimulation has been found by our group, but not by others. Long-term prognosis on Class IA antiarrhythmic medications that are highly effective at electrophysiologic study appears excellent.

Left Ventricular Function Improves after Pulmonary Valve Replacement in Patients with Previous Right Ventricular Outflow Tract Reconstruction and Biventricular Dysfunction

Science.gov (United States)

Kane, Colin; Kogon, Brian; Pernetz, Maria; McConnell, Michael; Kirshbom, Paul; Rodby, Katherine; Book, Wendy M.

2011-01-01

Congenital heart defects that have a component of right ventricular outflow tract obstruction, such as tetralogy of Fallot, are frequently palliated in childhood by disruption of the pulmonary valve. Although this can provide an initial improvement in quality of life, these patients are often left with severe pulmonary valve insufficiency. Over time, this insufficiency can lead to enlargement of the right ventricle and to the deterioration of right ventricular systolic and diastolic function. Pulmonary valve replacement in these patients decreases right ventricular volume overload and improves right ventricular performance. To date, few studies have examined the effects of pulmonary valve replacement on left ventricular function in patients with biventricular dysfunction. We sought to perform such an evaluation. Records of adult patients who had undergone pulmonary valve replacement from January 2003 through November 2006 were analyzed retrospectively. We reviewed preoperative and postoperative echocardiograms and calculated left ventricular function in 38 patients. In the entire cohort, the mean left ventricular ejection fraction increased by a mean of 0.07 after pulmonary valve replacement, which was a statistically significant change (P < 0.01). In patients with preoperative ejection fractions of less than 0.50, mean ejection fractions increased by 0.10. We conclude that pulmonary valve replacement in patients with biventricular dysfunction arising from severe pulmonary insufficiency and right ventricular enlargement can improve left ventricular function. Prospective studies are needed to verify this finding. PMID:21720459

Development of an inconel self powered neutron detector for in-core reactor monitoring

Energy Technology Data Exchange (ETDEWEB)

Alex, M. [Electronics Division, BARC, Mumbai (India)]. E-mail: maryalex@barc.gov.in; Ghodgaonkar, M.D. [Electronics Division, BARC, Mumbai (India)

2007-04-21

The paper describes the development and testing of an Inconel600 (2 mm diameterx21 cm long) self-powered neutron detector for in-core neutron monitoring. The detector has 3.5 mm overall diameter and 22 cm length and is integrally coupled to a 12 m long mineral insulated cable. The performance of the detector was compared with cobalt and platinum detectors of similar dimensions. Gamma sensitivity measurements performed at the {sup 60}Co irradiation facility in 14 MR/h gamma field showed values of -4.4x10{sup -18} A/R/h/cm (-9.3x10{sup -24} A/{gamma}/cm{sup 2}-s/cm), -5.2x10{sup -18} A/R/h/cm (-1.133x10{sup -23} A/{gamma}/cm{sup 2}-s/cm) and 34x10{sup -18} A/R/h/cm (7.14x10{sup -23} A/{gamma}/cm{sup 2}-s/cm) for the Inconel, Co and Pt detectors, respectively. The detectors together with a miniature gamma ion chamber and fission chamber were tested in the in-core Apsara Swimming Pool type reactor. The ion chambers were used to estimate the neutron and gamma fields. With an effective neutron cross-section of 4b, the Inconel detector has a total sensitivity of 6x10{sup -23} A/nv/cm while the corresponding sensitivities for the platinum and cobalt detectors were 1.69x10{sup -22} and 2.64x10{sup -22} A/nv/cm. The linearity of the detector responses at power levels ranging from 100 to 200 kW was within {+-}5%. The response of the detectors to reactor scram showed that the prompt response of the Inconel detector was 0.95 while it was 0.7 and 0.95 for the platinum and cobalt self-powered detectors, respectively. The detector was also installed in the horizontal flux unit of 540 MW Pressurised Heavy Water Reactor (PHWR). The neutron flux at the detector location was calculated by Triveni code. The detector response was measured from 0.02% to 0.07% of full power and showed good correlation between power level and detector signals. Long-term tests and the dynamic response of the detector to shut down in PHWR are in progress.

The right ventricular response to ventricular hypofunction in anteroseptal infarction

International Nuclear Information System (INIS)

Kanayama, Sugako

1992-01-01

Thirty-seven patients with acute anteroseptal infarction but not significant right coronary artery stenosis were examined by using thallium-201 (Tl-201) myocardial perfusion SPECT to determine how the right ventricular (RV) free wall responded to a severely impaired ventricular septum. The patients were divided into the group in which RV free wall was visualized on Tl-201 myocardial SPECT (n=19, RV(+) Group) and the group in which it was not visualized (n=18, RV(-) Group). The relationship between visualization of RV free wall and both RV and left ventricular (LV) function was evaluated. RV(+) Group had larger extent of anteroseptal necrosis and severer impairment of RV free wall, as compared with RV(-) Group. LV ejection fraction (LVEF) was significantly lower in RV(+) Group than RV(-) Group in both acute and chronic phases. Although RV ejection fraction (RVEF) in acute phase was significantly lower in RV(+) Group than RV(-) Group, it did not differ in chronic phase between the two groups. In RV(+) Group, RV stroke work index (RVSWI), pulmonary artery end diastolic pressure (PAEDP), and mean pulmonary artery pressure (MPA) in chronic phase showed a statistically significant increase compared with those in acute phase; these hemodynamic variables in chronic phase were also significantly higher than those in RV(-) Group. RV/LV ratio inversely correlated with LVEF, and both necrotic extent and impairment severity positively correlated with both PAEDP and MPA. RV free wall could be visualized more clearly, corresponding to extremely decreased LV function. These findings suggest that RV free wall may play an important role in maintaining LV and RV function when ventricular septum is severely impaired by anteroseptal infarction. (N.K.)

β1-Adrenoceptor blocker aggravated ventricular arrhythmia.

Science.gov (United States)

Wang, Yan; Patel, Dimpi; Wang, Dao Wu; Yan, Jiang Tao; Hsia, Henry H; Liu, Hao; Zhao, Chun Xia; Zuo, Hou Juan; Wang, Dao Wen

2013-11-01

To assess the impact of β1 -adrenoceptor blockers (β1 -blocker) and isoprenaline on the incidence of idiopathic repetitive ventricular arrhythmia that apparently decreases with preprocedural anxiety. From January 2010 to July 2012, six patients were identified who had idiopathic ventricular arrhythmias that apparently decreased (by greater than 90%) with preprocedural anxiety. The number of ectopic ventricular beats per hour (VPH) was calculated from Holter or telemetry monitoring to assess the ectopic burden. The mean VPH of 24 hours from Holter before admission (VPH-m) was used as baseline (100%) for normalization. β1 -Blockers, isoprenaline, and/or aminophylline were administrated successively on the ward and catheter lab to evaluate their effects on the ventricular arrhythmias. Among 97 consecutive patients with idiopathic ventricular arrhythmias, six had reduction in normalized VPHs in the hour before the scheduled procedure time from (104.6 ± 4.6%) to (2.8 ± 1.6%) possibly due to preprocedural anxiety (P < 0.05), then increased to (97.9 ± 9.7%) during β1 -blocker administration (P < 0.05), then quickly reduced to (1.6 ± 1.0%) during subsequent isoprenaline infusion. Repeated β1 -blocker quickly counteracted the inhibitory effect of isoprenaline, and VPHs increased to (120.9 ± 2.4%) from (1.6 ± 1.0%; P < 0.05). Isoprenaline and β1 -blocker showed similar effects on the arrhythmias in catheter lab. In some patients with structurally normal heart and ventricular arrhythmias there is a marked reduction of arrhythmias associated with preprocedural anxiety. These patients exhibit a reproducible sequence of β1 -blocker aggravation and catecholamine inhibition of ventricular arrhythmias, including both repetitive ventricular premature beats and monomorphic ventricular tachycardia. ©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.

Left Ventricular Myocardial Function in Children With Pulmonary Hypertension: Relation to Right Ventricular Performance and Hemodynamics.

Science.gov (United States)

Burkett, Dale A; Slorach, Cameron; Patel, Sonali S; Redington, Andrew N; Ivy, D Dunbar; Mertens, Luc; Younoszai, Adel K; Friedberg, Mark K

2015-08-01

Through ventricular interdependence, pulmonary hypertension (PH) induces left ventricular (LV) dysfunction. We hypothesized that LV strain/strain rate, surrogate measures of myocardial contractility, are reduced in pediatric PH and relate to invasive hemodynamics, right ventricular strain, and functional measures of PH. At 2 institutions, echocardiography was prospectively performed in 54 pediatric PH patients during cardiac catheterization, and in 54 matched controls. Patients with PH had reduced LV global longitudinal strain (LS; -18.8 [-17.3 to -20.4]% versus -20.2 [-19.0 to -20.9]%; P=0.0046) predominantly because of reduced basal (-12.9 [-10.8 to -16.3]% versus -17.9 [-14.5 to -20.7]%; Pright ventricular free-wall LS (r=0.64; PBrain natriuretic peptide levels correlated moderately with septal LS (r=0.48; P=0.0038). PH functional class correlated moderately with LV free-wall LS (r=-0.48; P=0.0051). The septum, shared between ventricles and affected by septal shift, was the most affected LV region in PH. Pediatric PH patients demonstrate reduced LV strain/strain rate, predominantly within the septum, with relationships to invasive hemodynamics, right ventricular strain, and functional PH measures. © 2015 American Heart Association, Inc.

Resolving the True Ventricular Mural Architecture

Directory of Open Access Journals (Sweden)

Robert S. Stephenson

2018-06-01

Full Text Available The precise nature of packing together of the cardiomyocytes within the ventricular walls has still to be determined. The spiraling nature of the chains of interconnected cardiomyocytes has long been recognized. As long ago as the end of the nineteenth century, Pettigrew had emphasized that the ventricular cone was not arranged on the basis of skeletal muscle. Despite this guidance, subsequent anatomists described entities such as “bulbo-spiral muscles”, with this notion of subunits culminating in the suggestion that the ventricular cone could be unwrapped so as to produce a “ventricular myocardial band”. Others, in contrast, had suggested that the ventricular walls were arranged on the basis of “sheets”, or more recently “sheetlets”, with investigators seeking to establishing the angulation of these entities using techniques such as magnetic resonance imaging. Our own investigations, in contrast, have shown that the cardiomyocytes are aggregated together within the supporting fibrous matrix so as to produce a three-dimensional myocardial mesh. In this review, we summarize the previous accounts, and provide the anatomical evidence we have thus far accumulated to support the model of the myocardial mesh. We show how these anatomic findings underscore the concept of the myocardial mesh functioning in antagonistic fashion. They lend evidence to support the notion that the ventricular myocardium works as a muscular hydrostat.

Self-Powered Neutron and Gamma Detectors for In-Core Measurements

International Nuclear Information System (INIS)

Strindehag, O.

1971-11-01

The performance of various types of self-powered neutron and gamma detectors intended for control and power distribution measurements in water cooled reactors is discussed. The self-powered detectors are compared with other types of in-core detectors and attention is paid to such properties as neutron and gamma sensitivity, high-temperature performance, burn-up rate and time of response. Also treated are the advantages and disadvantages of using gamma detector data for power distribution calculations instead of data from neutron detectors. With regard to neutron-sensitive detectors, results from several long-term experiments with vanadium and cobalt detectors are presented. The results include reliability and stability data for these two detector types and the Co build-up in cobalt detectors. Experimental results which reveal the fast response of cobalt detectors are presented, and the use of cobalt detectors in reactor safety systems is discussed. Experience of the design and installation of complete flux probes, electronic units and data processing systems for power reactors is reported. The investigation of gamma-sensitive detectors includes detectors with emitters of lead, zirconium, magnesium and Inconel. Measured gamma sensitivities from calibrations both in a reactor and in a gamma cell are given, and the signal levels of self-powered neutron and gamma detectors when applied to power reactors are compared

Self-Powered Neutron and Gamma Detectors for In-Core Measurements

Energy Technology Data Exchange (ETDEWEB)

Strindehag, O

1971-11-15

The performance of various types of self-powered neutron and gamma detectors intended for control and power distribution measurements in water cooled reactors is discussed. The self-powered detectors are compared with other types of in-core detectors and attention is paid to such properties as neutron and gamma sensitivity, high-temperature performance, burn-up rate and time of response. Also treated are the advantages and disadvantages of using gamma detector data for power distribution calculations instead of data from neutron detectors. With regard to neutron-sensitive detectors, results from several long-term experiments with vanadium and cobalt detectors are presented. The results include reliability and stability data for these two detector types and the Co build-up in cobalt detectors. Experimental results which reveal the fast response of cobalt detectors are presented, and the use of cobalt detectors in reactor safety systems is discussed. Experience of the design and installation of complete flux probes, electronic units and data processing systems for power reactors is reported. The investigation of gamma-sensitive detectors includes detectors with emitters of lead, zirconium, magnesium and Inconel. Measured gamma sensitivities from calibrations both in a reactor and in a gamma cell are given, and the signal levels of self-powered neutron and gamma detectors when applied to power reactors are compared

Right ventricular involvement in cardiac sarcoidosis demonstrated with cardiac magnetic resonance.

Science.gov (United States)

Smedema, Jan-Peter; van Geuns, Robert-Jan; Ainslie, Gillian; Ector, Joris; Heidbuchel, Hein; Crijns, Harry J G M

2017-11-01

Cardiac involvement in sarcoidosis is reported in up to 30% of patients. Left ventricular involvement demonstrated by contrast-enhanced cardiac magnetic resonance has been well validated. We sought to determine the prevalence and distribution of right ventricular late gadolinium enhancement in patients diagnosed with pulmonary sarcoidosis. We prospectively evaluated 87 patients diagnosed with pulmonary sarcoidosis with contrast-enhanced cardiac magnetic resonance for right ventricular involvement. Pulmonary artery pressures were non-invasively evaluated with Doppler echocardiography. Patient characteristics were compared between the groups with and without right ventricular involvement, and right ventricular enhancement was correlated with pulmonary hypertension, ventricular mass, volume, and systolic function. Left ventricular late gadolinium enhancement was demonstrated in 30 patients (34%). Fourteen patients (16%) had right ventricular late gadolinium enhancement, with sole right ventricular enhancement in only two patients. The pattern of right ventricular enhancement consisted of right ventricular outflow tract enhancement in 1 patient, free wall enhancement in 8 patients, ventricular insertion point enhancement in 10 patients, and enhancement of the right side of the interventricular septum in 11 patients. Pulmonary arterial hypertension correlated with the presence of right ventricular enhancement (P Right ventricular enhancement correlated with systolic ventricular dysfunction (P Right ventricular enhancement was present in 16% of patients diagnosed with pulmonary sarcoidosis and in 48% of patients with left ventricular enhancement. The presence of right ventricular enhancement correlated with pulmonary arterial hypertension, right ventricular systolic dysfunction, hypertrophy, and dilation. © 2017 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of the European Society of Cardiology.

Impact of the right ventricular lead position on clinical outcome and on the incidence of ventricular tachyarrhythmias in patients with CRT-D

DEFF Research Database (Denmark)

Kutyifa, Valentina; Bloch Thomsen, Poul Erik; Huang, David T.

2013-01-01

Data on the impact of right ventricular (RV) lead location on clinical outcome and ventricular tachyarrhythmias in cardiac resynchronization therapy with defibrillator (CRT-D) patients are limited.......Data on the impact of right ventricular (RV) lead location on clinical outcome and ventricular tachyarrhythmias in cardiac resynchronization therapy with defibrillator (CRT-D) patients are limited....

Right ventricular strain in heart failure: Clinical perspective.

Science.gov (United States)

Tadic, Marijana; Pieske-Kraigher, Elisabeth; Cuspidi, Cesare; Morris, Daniel A; Burkhardt, Franziska; Baudisch, Ana; Haßfeld, Sabine; Tschöpe, Carsten; Pieske, Burket

2017-10-01

The number of studies demonstrating the importance of right ventricular remodelling in a wide range of cardiovascular diseases has increased in the past two decades. Speckle-tracking imaging provides new variables that give comprehensive information about right ventricular function and mechanics. In this review, we summarize current knowledge of right ventricular mechanics in heart failure with reduced ejection fraction and preserved ejection fraction. We searched PubMed, MEDLINE, Ovid and Embase databases for studies published from January 2000 to December 2016 in the English language using the following keywords: "right ventricle"; "strain"; "speckle tracking"; "heart failure with reduced ejection fraction"; and "heart failure with preserved ejection fraction". Investigations showed that right ventricular dysfunction is associated with higher cardiovascular and overall mortality in patients with heart failure, irrespective of ejection fraction. The number of studies investigating right ventricular strain in patients with heart failure with reduced ejection fraction is constantly increasing, whereas data on right ventricular mechanics in patients with heart failure with preserved ejection fraction are limited. Given the high feasibility, accuracy and clinical implications of right ventricular strain in the population with heart failure, it is of great importance to try to include the evaluation of right ventricular strain as a regular part of each echocardiographic examination in patients with heart failure. However, further investigations are necessary to establish right ventricular strain as a standard variable for decision-making. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Right ventricular function in patients with dilated cardiomyopathy

International Nuclear Information System (INIS)

Kubota, Shuhei; Kubota, Sachio; Iwase, Takashi; Iizuka, Toshio; Imai, Susumu; Murata, Kazuhiko; Inoue, Tomio; Suzuki, Tadashi; Sasaki, Yasuhito.

1993-01-01

The characteristics and pathogenesis of right ventricular dysfunction in 14 patients with dilated cardiomyopathy (DCM) were investigated by equilibrium right ventricular blood pool scintigraphy using ultrashort-lifetime 81m Kr. Thirteen patients with severe left ventricular dysfunction due to old anterior myocardial infarction (OMI) and nine normal subjects were used as controls. The right ventricular end-diastolic pressure and volume index, mean pulmonary arterial pressure, and total pulmonary vascular resistance index were almost the same in the DCM and OMI patients. The right ventricular ejection fraction was 44.2±6.0% (mean±SD) in DCM patients and 47.1±7.9% in OMI patients, both significantly lower than those in the normal subjects (54.5±5.3%), but with no difference between the two case groups. The right ventricular peak filling rate was significantly reduced in both case groups as compared with the normal subjects (2.46±0.81 EDV/sec). The reduction was significantly greater (p 81m Kr blood pool scintigraphy is useful in the study of the right ventricular systolic and diastolic function. The diastolic parameters are more sensitive indicators for evaluation of right ventricular function in DCM than the systolic parameters. (author)

Arrhythmogenic right ventricular cardiomyopathy in a dog : case report

Directory of Open Access Journals (Sweden)

A.J. Möhr

2000-07-01

Full Text Available An 8-month-old Labrador retriever bitch was evaluated for sudden-onset, progressive abdominal distension. Physical examination revealed an exaggerated inspiratory effort, severe ascites, bilateral jugular vein distension, and hypokinetic femoral arterial pulses. Thoracic auscultation detected tachycardia with muffled heart sounds, without audible cardiac murmurs. Thoracic radiographs identified severe right ventricular enlargement and pleural effusion. The electrocardiogram was consistent with incomplete right bundle branch block or right ventricular enlargement. Echocardiography demonstrated severe right ventricular and atrial dilation, secondary tricuspid regurgitation, and thinning and hypocontractility of the right ventricular myocardium. Left heart chamber sizes were slightly decreased, with normal left ventricular contractility. Adiagnosis of arrhythmogenic right ventricular cardiomyopathy was reached, based on the characteristic clinical, electrocardiographic, radiographic and echocardiographic findings, and the exclusion of other causes of isolated right ventricular failure. Treatment effected good control of clinical signs, until acutely decompensated congestive right heart failure led to euthanasia after 4 months. Arrhythmogenic right ventricular cardiomyopathy is a well-described clinical entity in humans, and has previously been documented in 3 male dogs. The condition is characterised by progressive fibro-adipose replacement of right ventricular myocardium, while the left ventricle usually remains unaffected. It should be considered a differential diagnosis in any young dog presented with isolated right heart failure, syncope, or unexplained ventricular tachyarrhythmias. This article reports the 1st case of arrhythmogenic right ventricular cardiomyopathy in a female dog, and highlights its echocardiographic features.

The influence of type 2 diabetes and gender on ventricular repolarization dispersion in patients with sub-clinic left ventricular diastolic dysfunction

OpenAIRE

Jani, Ylber; Kamberi, Ahmet; Xhunga, Sotir; Pocesta, Bekim; Ferati, Fatmir; Lala, Dali; Zeqiri, Agim; Rexhepi, Atila

2015-01-01

Objective: To assess the influence of type 2 DM and gender, on the QT dispersion, Tpeak-Tend dispersion of ventricular repolarization, in patients with sub-clinic left ventricular diastolic dysfunction of the heart. Background: QT dispersion, that reflects spatial inhomogeneity in ventricular repolarization, Tpeak-Tend dispersion, this on the other hand reflects transmural inhomogeneity in ventricular repolarization, that is increased in an early stage of cardiomyopathy, and in patients with ...

Taquicardia ventricular del tracto de salida del ventrículo derecho durante el embarazo

Directory of Open Access Journals (Sweden)

Ariel K. Saad

2012-06-01

Full Text Available Durante el embarazo aumentan el metabolismo basal, el consumo de O2, la frecuencia cardíaca, el volumen sistólico, el volumen minuto y la volemia y disminuyen la tensión arterial y la resistencia periférica. Diferentes estudios han demostrado que durante este período la posibilidad de que ocurra una arritmia cardíaca o se produzca la exacerbación de una arritmia preexistente es mayor. No obstante, en su enorme mayoría carecen de importancia pronóstica tanto para la madre como para el feto. La taquicardia ventricular del tracto de salida del ventrículo derecho es una arritmia poco frecuente y su aparición se ha correlacionado con el aumento del tono adrenérgico. Se presentan los casos de dos pacientes que mostraron en el curso de la gestación reiterados episodios de taquicardia ventricular del tracto de salida del ventrículo derecho. Se analiza la asociación del embarazo con la ocurrencia de trastornos del ritmo cardíaco.

Is right ventricular mid-septal pacing superior to apical pacing in patients with high degree atrio-ventricular block and moderately depressed left ventricular function?

Science.gov (United States)

Chen, Kang; Mao, Ye; Liu, Shao-hua; Wu, Qiong; Luo, Qing-zhi; Pan, Wen-qi; Jin, Qi; Zhang, Ning; Ling, Tian-you; Chen, Ying; Gu, Gang; Shen, Wei-feng; Wu, Li-qun

2014-06-01

We are aimed to investigate whether right ventricular mid-septal pacing (RVMSP) is superior to conventional right ventricular apical pacing (RVAP) in improving clinical functional capacity and left ventricular ejection fraction (LVEF) for patients with high-degree atrio-ventricular block and moderately depressed left ventricle (LV) function. Ninety-two patients with high-degree atrio-ventricular block and moderately reduced LVEF (ranging from 35% to 50%) were randomly allocated to RVMSP (n=45) and RVAP (n=47). New York Heart Association (NYHA) functional class, echocardiographic LVEF, and distance during a 6-min walk test (6MWT) were determined at 18 months after pacemaker implantation. Serum levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) were measured using an enzyme-linked immunosorbent assay (ELISA) kit. Compared with baseline, NYHA functional class remained unchanged at 18 months, distance during 6MWT (485 m vs. 517 m) and LVEF (36.7% vs. 41.8%) were increased, but BNP levels were reduced (2352 pg/ml vs. 710 pg/ml) in the RVMSP group compared with those in the RVAP group, especially in patients with LVEF 35%-40% (for all comparisons, Pfunction capacity and LV function measurements were not significantly changed in patients with RVAP, despite the pacing measurements being similar in both groups, such as R-wave amplitude and capture threshold. RVMSP provides a better clinical utility, compared with RVAP, in patients with high-degree atrioventricular block and moderately depressed LV function whose LVEF levels ranged from 35% to 40%.

A High Temperature-Tolerant and Radiation-Resistant In-Core Neutron Sensor for Advanced Reactors. Final report

Energy Technology Data Exchange (ETDEWEB)

Cao, Lei [The Ohio State Univ., Columbus, OH (United States); Miller, Don [The Ohio State Univ., Columbus, OH (United States)

2015-01-23

The objectives of this project are to develop a small and reliable gallium nitride (GaN) neutron sensor that is capable of withstanding high neutron fluence and high temperature, isolating gamma background, and operating in a wide dynamic range. The first objective will be the understanding of the fundamental materials properties and electronic response of a GaN semiconductor materials and device in an environment of high temperature and intense neutron field. To achieve such goal, an in-situ study of electronic properties of GaN device such as I-V, leakage current, and charge collection efficiency (CCE) in high temperature using an external neutron beam will be designed and implemented. We will also perform in-core irradiation of GaN up to the highest yet fast neutron fluence and an off-line performance evaluation.

A High Temperature-Tolerant and Radiation-Resistant In-Core Neutron Sensor for Advanced Reactors. Final report

International Nuclear Information System (INIS)

Cao, Lei; Miller, Don

2015-01-01

The objectives of this project are to develop a small and reliable gallium nitride (GaN) neutron sensor that is capable of withstanding high neutron fluence and high temperature, isolating gamma background, and operating in a wide dynamic range. The first objective will be the understanding of the fundamental materials properties and electronic response of a GaN semiconductor materials and device in an environment of high temperature and intense neutron field. To achieve such goal, an in-situ study of electronic properties of GaN device such as I-V, leakage current, and charge collection efficiency (CCE) in high temperature using an external neutron beam will be designed and implemented. We will also perform in-core irradiation of GaN up to the highest yet fast neutron fluence and an off-line performance evaluation.

Noninvasive reconstruction of the three-dimensional ventricular activation sequence during pacing and ventricular tachycardia in the rabbit heart.

Science.gov (United States)

Han, Chengzong; Pogwizd, Steven M; Killingsworth, Cheryl R; He, Bin

2011-01-01

Ventricular arrhythmias represent one of leading causes for sudden cardiac death, a significant problem in public health. Noninvasive imaging of cardiac electric activities associated with ventricular arrhythmias plays an important role in better our understanding of the mechanisms and optimizing the treatment options. The present study aims to rigorously validate a novel three-dimensional (3-D) cardiac electrical imaging (3-DCEI) technique with the aid of 3-D intra-cardiac mapping during paced rhythm and ventricular tachycardia (VT) in the rabbit heart. Body surface potentials and intramural bipolar electrical recordings were simultaneously measured in a closed-chest condition in thirteen healthy rabbits. Single-site pacing and dual-site pacing were performed from ventricular walls and septum. VTs and premature ventricular complexes (PVCs) were induced by intravenous norepinephrine (NE). The non-invasively imaged activation sequence correlated well with invasively measured counterparts, with a correlation coefficient of 0.72 and a relative error of 0.30 averaged over all paced beats and NE-induced PVCs and VT beats. The averaged distance from imaged site of initial activation to measured site determined from intra-cardiac mapping was ∼5mm. These promising results suggest that 3-DCEI is feasible to non-invasively localize the origins and image activation sequence of focal ventricular arrhythmias.

Preliminary analysis on in-core fuel management optimization of molten salt pebble-bed reactor

International Nuclear Information System (INIS)

Xia Bing; Jing Xingqing; Xu Xiaolin; Lv Yingzhong

2013-01-01

The Nuclear Hot Spring (NHS) is a molten salt pebble-bed reactor featured by full power natural circulation. The unique horizontal coolant flow of the NHS demands the fuel recycling schemes based on radial zoning refueling and the corresponding method of fuel management optimization. The local searching algorithm (LSA) and the simulated annealing algorithm (SAA), the stochastic optimization methods widely used in the refueling optimization problems in LWRs, were applied to the analysis of refueling optimization of the NHS. The analysis results indicate that, compared with the LSA, the SAA can survive the traps of local optimized solutions and reach the global optimized solution, and the quality of optimization of the SAA is independent of the choice of the initial solution. The optimization result gives excellent effects on the in-core power flattening and the suppression of fuel center temperature. For the one-dimensional zoning refueling schemes of the NHS, the SAA is an appropriate optimization method. (authors)

Trends and results in In-Core management for the Kozloduy NPP WWER-440 reactors

International Nuclear Information System (INIS)

Haralampieva, Tz.; Antov, A.; Georgieva, N.; Spasova, V.

2001-01-01

The paper presents the experience gained during the design and operation of the last fuel cycles of the four WWER-440/V-230 units at Kozloduy NPP. High efficiency and economy of the fuel utilization requires very precise procedures for fuel in-core management, including calculations and analyses for reloading scheme design, compared with results from operational measurements and fuel cycle efficiency. The paper describes the main stages of implementation of advanced fuel assemblies in the Kozloduy NPP WWER-440 reactors. New advanced fuel has been implemented after the completion of comprehensive neutron-physical, thermal-hydraulic and thermal-mechanical analyses by using advanced computer codes. As a general task of the fuel cycle improvements it is pointed the increasing of the final fuel burnup and decreasing of the number of spent fuel assemblies. Series of calculations and analyses, related to the introducing of the advanced fuel assemblies and improvement of the fuel cycle characteristics have been carried out to guarantee the safe operation and fuel reliability

First in-core measurement results obtained with the innovative mobile calorimeter CALMOS inside the OSIRIS material testing reactor

International Nuclear Information System (INIS)

Carcreff, Hubert; Salmon, Laurent; Courtaux, Cedric

2014-01-01

Nuclear heating rate inside an MTR has to be known in order to design and to run irradiation experiments which have to fulfill target temperature constraints. This measurement is usually carried out by calorimetry. An innovative calorimetric system, CALMOS, has been studied and built in 2011 for the 70 MWth OSIRIS reactor operated by CEA. Thanks to a new calorimetric probe, associated to a specific displacement system, it provides measurements along the fissile height and above the core. Development of the calorimetric probe required manufacturing and irradiation of mock-ups in the ex-core area, where nuclear heating rate does not exceed 2 W.g -1 . The calorimeter working mode, the different measurement procedures, main modeling and ex-core experimental results have been already presented in previous papers. In this paper, we present in-core results obtained from 2011 to 2013 with the final device. For the first time, this new experimental measurement system was operated in several experimental locations, with nominal in-core thermal hydraulic conditions, nominal neutron flux and nuclear heating rate up to 6 W.g -1 (in graphite). After a brief presentation of the displacement system specificities, first nuclear heating distributions are presented and discussed. The Finite Element model of the calorimeter was upgraded in order to match calculated temperatures with measured ones. This 'validated' model allowed to estimate a Kc factor which tends to correct small nonlinearities when heating rate is calculated from the 'calibration method'. A comparison is made between nuclear heating rates determined from 'calibration' and 'zero methods'. In addition, an evaluation of the global uncertainty associated to the measurements is detailed. Finally, a comparison is made with available measurements obtained from previous calorimeters. (authors)

Delayed recovery of right ventricular systolic function after repair of long-standing tricuspid regurgitation associated with severe right ventricular failure.

Science.gov (United States)

Kim, Jong Hun; Kim, Kyung Hwa; Choi, Jong Bum; Kuh, Ja Hong

2016-03-01

After tricuspid valve surgery for long-standing tricuspid regurgitation associated with right ventricular failure, reverse remodelling of the enlarged right ventricle, including recovery of right ventricular systolic function, is unpredictable. We present the case of a 31-year old man with early reduction of dilated right ventricular dimensions and delayed recovery of impaired right ventricular systolic function after valve repair for traumatic tricuspid regurgitation lasting 16 years. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Organization of the in-core control system connection with the M-6000 computer

International Nuclear Information System (INIS)

Golovanov, M.N.; Duma, V.R.; Levin, G.L.; Filatov, V.P.

1978-01-01

Problems of organizing communication of a digital computer with the equipment of the in-core control system (CC) are discussed. Three possible modes of joint operation of the CC equipment and the digital computer are given. The off-line control device provides data collection, preliminary processing and recording servicing of peripheral requests, and data exchange with the digital computer; computer-controlled operation of the equipment makes it possible to control input-output operations of the CCS equipment, and also to retain the working capacity of the CCS system when the off-line control device is failed; during file exchange the data are transferred between the computer and the CCS equipment. Requirements for the communication unit design are drawn up. An analysis of existing methods of a digital computer interface with the equipment is presented, and substantiation of the proposed variant of connection of the communication unit directly to the branch highway is given. Operation of the CCS equipment under various conditions is considered. The flowsheet and description of the interface of the M-6000 computer with the CCS equipment are given

Right Ventricular Pseudoaneurysm Following Endomyocardial Biopsy.

Science.gov (United States)

Pita; Santos; Manteiga; Rodriguez; Beiras

1996-03-01

Ventricular perforation is an unusual complication after endomyocardial biopsy in heart transplanted patients. We report a case of asymptomatic right ventricular perforation and pseudoaneurysm formation, secondary to endomyocardial biopsy, diagnosed by angiography. The spontaneous obliteration of the pseudoaneurysm was observed.

Evaluation of right ventricular volumes measured by magnetic resonance imaging

DEFF Research Database (Denmark)

Møgelvang, J; Stubgaard, M; Thomsen, C

1988-01-01

stroke volume was calculated as the difference between end-diastolic and end-systolic volume and compared to left ventricular stroke volume and to stroke volume determined simultaneously by a classical indicator dilution technique. There was good agreement between right ventricular stroke volume......Right ventricular volumes were determined in 12 patients with different levels of right and left ventricular function by magnetic resonance imaging (MRI) using an ECG gated multisection technique in planes perpendicular to the diastolic position of the interventricular septum. Right ventricular...... determined by MRI and by the indicator dilution method and between right and left ventricular stroke volume determined by MRI. Thus, MRI gives reliable values not only for left ventricular volumes, but also for right ventricular volumes. By MRI it is possible to obtain volumes from both ventricles...

Impact of shelf life on measured prompt fraction of spare Inconel in-core flux detectors

Energy Technology Data Exchange (ETDEWEB)

Mohindra, VK; Sadeghi, S. [Atomic Energy of Canada Limited, Mississauga, Ontario (Canada); Crouse, B. [Darlington Nuclear Generating Station, Bowmanville, Ontario (Canada)

2008-07-01

Prompt fraction measurements associated with spare self-powered Inconel In-Core Flux Detectors (ICFDs) carried out a few years after installation on Shut Down System number 1 (SDS1) and Reactor Regulating System (RRS) at Darlington Nuclear Generating Station (DNGS), were found to be lower than those of the original detectors. These detectors, spares and originals, were manufactured in the late 80s, however, the former were kept at manufacturer's warehouse and latter were installed in the reactor core within a few years after manufacturing. Although the prompt fractions of the spare detectors were relatively low, the electronic/electrical behavior of the spare detectors was intact. The first batch of the original detectors performed as per the design requirements. Therefore, it is suspected that during shelf life, spare Inconel in-core flux detectors underwent changes that lowered their measured values of prompt fraction, which were taken within a few years after installation in the reactor. Detailed study of detectors' material composition and impurity concentrations revealed no association with the lower prompt fraction measurements. The evaluation of the limited data of the original and spare Inconel ICFDs installed at Darlington showed: 1. The reduction in prompt fraction was roughly proportional to the shelf life of the detectors; and 2. The rate of reduction in prompt fraction during storage was about double the rate of reduction during operation in the reactor. Above observations were based on the data provided by DNGS for a few detectors. The purpose of this paper is two fold, firstly to present the results of the complete study carried out to investigate the cause of relatively low prompt fractions measured on spare SDS1 and RRS Inconel ICFDs at DNGS, and secondly to generate interest/awareness within other CANDU utilities to add to the database of prompt fractions of spare Inconel ICFDs measured after installation. The data will help to improve

Genetics Home Reference: arrhythmogenic right ventricular cardiomyopathy

Science.gov (United States)

... cardiomyopathy Merck Manual Consumer Version: Cardiomyopathy Merck Manual Consumer Version: Overview of Abnormal Heart Rhythms Orphanet: Arrhythmogenic right ventricular cardiomyopathy Orphanet: Familial isolated arrhythmogenic right ventricular ...

Left Ventricular Assist Devices

Directory of Open Access Journals (Sweden)

Khuansiri Narajeenron

2017-04-01

Full Text Available Audience: The audience for this classic team-based learning (cTBL session is emergency medicine residents, faculty, and students; although this topic is applicable to internal medicine and family medicine residents. Introduction: A left ventricular assist device (LVAD is a mechanical circulatory support device that can be placed in critically-ill patients who have poor left ventricular function. After LVAD implantation, patients have improved quality of life.1 The number of LVAD patients worldwide continues to rise. Left-ventricular assist device patients may present to the emergency department (ED with severe, life-threatening conditions. It is essential that emergency physicians have a good understanding of LVADs and their complications. Objectives: Upon completion of this cTBL module, the learner will be able to: 1 Properly assess LVAD patients’ circulatory status; 2 appropriately resuscitate LVAD patients; 3 identify common LVAD complications; 4 evaluate and appropriately manage patients with LVAD malfunctions. Method: The method for this didactic session is cTBL.

The influence of type 2 diabetes and gender on ventricular repolarization dispersion in patients with sub-clinic left ventricular diastolic dysfunction.

Science.gov (United States)

Jani, Ylber; Kamberi, Ahmet; Xhunga, Sotir; Pocesta, Bekim; Ferati, Fatmir; Lala, Dali; Zeqiri, Agim; Rexhepi, Atila

2015-01-01

To assess the influence of type 2 DM and gender, on the QT dispersion, Tpeak-Tend dispersion of ventricular repolarization, in patients with sub-clinic left ventricular diastolic dysfunction of the heart. QT dispersion, that reflects spatial inhomogeneity in ventricular repolarization, Tpeak-Tend dispersion, this on the other hand reflects transmural inhomogeneity in ventricular repolarization, that is increased in an early stage of cardiomyopathy, and in patients with left ventricular diastolic dysfunction, as well. The left ventricular diastolic dysfunction, a basic characteristic of diabetic heart disease (diabetic cardiomyopathy), that developes earlier than systolic dysfunction, suggests that diastolic markers might be sensitive for early cardiac injury. It is also demonstrated that gender has complex influence on indices of myocardial repolarization abnormalities such as QT interval and QT dispersion. We performed an observational study including 300 diabetic patients with similar epidemiological-demographic characteristics recruited in our institution from May 2009 to July 2014, divided into two groups. Demographic and laboratory echocardiographic data were obtained, twelve lead resting electrocardiography, QT, QTc, Tpeak-Tend-intervals and dispersion, were determined manually, and were compared between various groups. For statistical analysis a t-test, X(2) test, and logistic regression are used according to the type of variables. A p value <0.05 was considered statistically significant for a confidence interval of 95%. QTc max. interval, QTc dispersion and Tpeak-Tend dispersion, were significantly higher in diabetic group with subclinical LV (left ventricular) diastolic dysfunction, than in diabetic group with normal left ventricular diastolic function (445.24±14.7 ms vs. 433.55±14.4 ms, P<0.000; 44.98±18.78 ms vs. 32.05±17.9 ms, P<0.000; 32.60±1.6 ms vs. 17.46±2.0 ms, P<0.02. Prolonged QTc max. interval was found in 33% of patients, indiabetic group

PWR in-core nuclear fuel management optimization utilizing nodal (non-linear NEM) generalized perturbation theory

International Nuclear Information System (INIS)

Maldonado, G.I.; Turinsky, P.J.; Kropaczek, D.J.

1993-01-01

The computational capability of efficiently and accurately evaluate reactor core attributes (i.e., k eff and power distributions as a function of cycle burnup) utilizing a second-order accurate advanced nodal Generalized Perturbation Theory (GPT) model has been developed. The GPT model is derived from the forward non-linear iterative Nodal Expansion Method (NEM) strategy, thereby extending its inherent savings in memory storage and high computational efficiency to also encompass GPT via the preservation of the finite-difference matrix structure. The above development was easily implemented into the existing coarse-mesh finite-difference GPT-based in-core fuel management optimization code FORMOSA-P, thus combining the proven robustness of its adaptive Simulated Annealing (SA) multiple-objective optimization algorithm with a high-fidelity NEM GPT neutronics model to produce a powerful computational tool used to generate families of near-optimum loading patterns for PWRs. (orig.)

Development and manufacturing of special fission chambers for in-core measurement requirements in nuclear reactors

International Nuclear Information System (INIS)

Geslot, B.; Berhouet, F.; Oriol, L.; Breaud, S.; Jammes, C.; Filliatre, P.; Villard, J. F.

2009-01-01

The Dosimetry Command control and Instrumentation Laboratory (LDCI) at CEA/Cadarache is specialized in the development, design and manufacturing of miniature fission chambers (from 8 mm down to 1.5 mm in diameter). The LDCI fission chambers workshop specificity is its capacity to manufacture and distribute special fission chambers with fissile deposits other than U 235 (typically Pu 242 , Np 237 , U 238 , Th 232 ). We are also able to define the characteristics of the detector for any in-core measurement requirements: sensor geometry, fissile deposit material and mass, filling gas composition and pressure, operating mode (pulse, current or Campbelling) with associated cable and electronics. The fission chamber design relies on numerical simulation and modeling tools developed by the LDCI. One of our present activities in fission chamber applications is to develop a fast neutron flux instrumentation using Campbelling mode dedicated to measurements in material testing reactors. (authors)

A Prospective Study of Ripple Mapping the Post-Infarct Ventricular Scar to Guide Substrate Ablation for Ventricular Tachycardia.

Science.gov (United States)

Luther, Vishal; Linton, Nick W F; Jamil-Copley, Shahnaz; Koa-Wing, Michael; Lim, Phang Boon; Qureshi, Norman; Ng, Fu Siong; Hayat, Sajad; Whinnett, Zachary; Davies, D Wyn; Peters, Nicholas S; Kanagaratnam, Prapa

2016-06-01

Post-infarct ventricular tachycardia is associated with channels of surviving myocardium within scar characterized by fractionated and low-amplitude signals usually occurring late during sinus rhythm. Conventional automated algorithms for 3-dimensional electro-anatomic mapping cannot differentiate the delayed local signal of conduction within the scar from the initial far-field signal generated by surrounding healthy tissue. Ripple mapping displays every deflection of an electrogram, thereby providing fully informative activation sequences. We prospectively used CARTO-based ripple maps to identify conducting channels as a target for ablation. High-density bipolar left ventricular endocardial electrograms were collected using CARTO3v4 in sinus rhythm or ventricular pacing and reviewed for ripple mapping conducting channel identification. Fifteen consecutive patients (median age 68 years, left ventricular ejection fraction 30%) were studied (6 month preprocedural implantable cardioverter defibrillator therapies: median 19 ATP events [Q1-Q3=4-93] and 1 shock [Q1-Q3=0-3]). Scar (ripple mapping conducting channels were seen within each scar (length 60 mm; initial component 0.44 mV; delayed component 0.20 mV; conduction 55 cm/s). Ablation was performed along all identified ripple mapping conducting channels (median 18 lesions) and any presumed interconnected late-activating sites (median 6 lesions; Q1-Q3=2-12). The diastolic isthmus in ventricular tachycardia was mapped in 3 patients and colocated within the ripple mapping conducting channels identified. Ventricular tachycardia was noninducible in 85% of patients post ablation, and 71% remain free of ventricular tachycardia recurrence at 6-month median follow-up. Ripple mapping can be used to identify conduction channels within scar to guide functional substrate ablation. © 2016 American Heart Association, Inc.

follow-up of patients with arrhythmogenic right ventricular

African Journals Online (AJOL)

was sudden, 1 patient died due to left ventricular failure, and ... Arrhythmogenic right ventricular cardiomyopathy/ dysplasia .... hypertension and from atrial fibrillation that developed 2.4 .... of left ventricular function was global without regional ..... 99mTc he brain si before a acid (G minute his sem next 3 - his sem showed.

Síndrome da disfunção apical reversível (Takotsubo Transient ventricular dysfunction (Takotsubo cardiomyopathy

Directory of Open Access Journals (Sweden)

José Marconi Almeida de Sousa

2005-04-01

Full Text Available Homem portador de miastenia gravis, internado por descompensação da doença de base, em insuficiência respiratória aguda. Na evolução, apresentou quadro sugestivo de infarto agudo do miocárdio, com alterações eletrocardiográficas e enzimáticas compatíveis com o diagnóstico. Submetido a coronariografia de urgência, não evidenciou obstrução coronariana grave, entretanto o ventrículo esquerdo apresentava disfunção sistólica importante, com alteração característica pela ventriculografia da síndrome descrita como disfunção ventricular transitória ou síndrome de Takotsubo. Na evolução, houve completa recuperação das alterações eletrocardiográficas e da função ventricular sistólica avaliada pelo ecocardiograma, confirmando a síndrome.The patient was a male with myasthenia gravis, hospitalized with acute respiratory failure due to decompensation of the underlying disease. He evolved with findings suggestive of acute myocardial infarction, with electrocardiographic and enzymatic alterations compatible with that diagnosis. The patient underwent emergency coronary angiography, which showed no severe coronary obstruction, although his left ventricle had significant systolic dysfunction with characteristic alterations, on ventriculography, of the syndrome described as transient ventricular dysfunction or Takotsubo syndrome. On evolution, complete recovery of the electrocardiographic alterations and systolic ventricular function assessed on echocardiography occurred, confirming the syndrome.

Relationship of left ventricular systolic function to persistence or development of electrocardiographic left ventricular hypertrophy in hypertensive patients

DEFF Research Database (Denmark)

Okin, Peter M; Wachtell, Kristian; Gerdts, Eva

2014-01-01

left ventricular systolic function in patients with new or persistent ECG LVH. METHODS: Baseline and year-3 ECG LVH and left ventricular midwall shortening (MWS) were examined in 725 hypertensive patients in the Losartan Intervention For Endpoint reduction in hypertension (LIFE) echocardiographic...... 1.03-3.50, P = 0.040) at year 3. CONCLUSION: Persistence or development of new ECG LVH during antihypertensive therapy is associated with an increased risk of left ventricular systolic dysfunction after 3 years' follow-up. These findings provide insight into a possible mechanism by which changes......BACKGROUND: Persistence or development of ECG left ventricular hypertrophy (LVH) by Cornell product criteria is associated with an increased risk of developing heart failure compared with regression or continued absence of LVH. We postulated that this association might be in part mediated via worse...

Fibroblasts and the extracellular matrix in right ventricular disease.

Science.gov (United States)

Frangogiannis, Nikolaos G

2017-10-01

Right ventricular failure predicts adverse outcome in patients with pulmonary hypertension (PH), and in subjects with left ventricular heart failure and is associated with interstitial fibrosis. This review manuscript discusses the cellular effectors and molecular mechanisms implicated in right ventricular fibrosis. The right ventricular interstitium contains vascular cells, fibroblasts, and immune cells, enmeshed in a collagen-based matrix. Right ventricular pressure overload in PH is associated with the expansion of the fibroblast population, myofibroblast activation, and secretion of extracellular matrix proteins. Mechanosensitive transduction of adrenergic signalling and stimulation of the renin-angiotensin-aldosterone cascade trigger the activation of right ventricular fibroblasts. Inflammatory cytokines and chemokines may contribute to expansion and activation of macrophages that may serve as a source of fibrogenic growth factors, such as transforming growth factor (TGF)-β. Endothelin-1, TGF-βs, and matricellular proteins co-operate to activate cardiac myofibroblasts, and promote synthesis of matrix proteins. In comparison with the left ventricle, the RV tolerates well volume overload and ischemia; whether the right ventricular interstitial cells and matrix are implicated in these favourable responses remains unknown. Expansion of fibroblasts and extracellular matrix protein deposition are prominent features of arrhythmogenic right ventricular cardiomyopathies and may be implicated in the pathogenesis of arrhythmic events. Prevailing conceptual paradigms on right ventricular remodelling are based on extrapolation of findings in models of left ventricular injury. Considering the unique embryologic, morphological, and physiologic properties of the RV and the clinical significance of right ventricular failure, there is a need further to dissect RV-specific mechanisms of fibrosis and interstitial remodelling. Published on behalf of the European Society of

Free and conjugated dopamine in human ventricular fluid

International Nuclear Information System (INIS)

Sharpless, N.S.; Thal, L.J.; Wolfson, L.I.; Tabaddor, K.; Tyce, G.M.; Waltz, J.M.

1981-01-01

Free dopamine and an acid hydrolyzable conjugate of dopamine were measured in human ventricular fluid specimens with a radioenzymatic assay and by high performance liquid chromatography (HPLC) with electrochemical detection. Only trace amounts of free norepinephrine and dopamine were detected in ventricular fluid from patients with movement disorders. When the ventricular fluid was hydrolyzed by heating in HClO 4 or by lyophilization in dilute HClO 4 , however, a substantial amount of free dopamine was released. Values for free plus conjugated dopamine in ventricular fluid from patients who had never taken L-DOPA ranged from 139 to 340 pg/ml when determined by HPLC and from 223 to 428 pg/ml when measured radioenzymatically. The correlation coefficient for values obtained by the two methods in the same sample of CSF was 0.94 (P<0.001). Patients who had been treated with L-DOPA had higher levels of conjugated dopamine in their ventricular CSF which correlated inversely with the time between the last dose of L-DOPA and withdrawal of the ventricular fluid. Additionally, one patient with acute cerebral trauma had elevated levels of free norepinephrine and both free and conjugated dopamine in his ventricular fluid. Conjugation may be an important inactivation pathway for released dopamine in man. (Auth.)

Alternative right ventricular pacing sites.

Science.gov (United States)

Łuciuk, Dariusz; Łuciuk, Marek; Gajek, Jacek

2015-01-01

The main adverse effect of chronic stimulation is stimulation-induced heart failure in case of ventricular contraction dyssynchrony. Because of this fact, new techniques of stimulation should be considered to optimize electrotherapy. One of these methods is pacing from alternative right ventricular sites. The purpose of this article is to review currently accumulated data about alternative sites of cardiac pacing. Medline and PubMed bases were used to search English and Polish reports published recently. Recent studies report a deleterious effect of long term apical pacing. It is suggested that permanent apical stimulation, by omitting physiological conduction pattern with His-Purkinie network, may lead to electrical and mechanical dyssynchrony of heart muscle contraction. In the long term this pathological situation can lead to severe heart failure and death. Because of this, scientists began to search for some alternative sites of cardiac pacing to reduce the deleterious effect of stimulation. Based on current accumulated data, it is suggested that the right ventricular outflow tract, right ventricular septum, direct His-bundle or biventricular pacing are better alternatives due to more physiological electrical impulse propagation within the heart and the reduction of the dyssynchrony effect. These methods should preserve a better left ventricular function and prevent the development of heart failure in permanent paced patients. As there is still not enough, long-term, randomized, prospective, cross-over and multicenter studies, further research is required to validate the benefits of using this kind of therapy. The article should pay attention to new sites of cardiac stimulation as a better and safer method of treatment.

Left ventricular apical ballooning syndrome

International Nuclear Information System (INIS)

Rahman, N.; Tai, J.; Soofi, A.

2007-01-01

The transient left ventricular apical ballooning syndrome, also known as Takotsubo cardiomyopathy, is characterized by transient left ventricular dysfunction in the absence of obstructive epicardial coronary disease. Although the syndrome has been reported in Japan since 1990, it is rare in other regions. Rapid recognition of the syndrome can modify the diagnostic and therapeutic attitude i.e. avoiding thrombolysis and performing catheterization in the acute phase. (author)

Parasympathetic neurons in the cranial medial ventricular fat pad on the dog heart selectively decrease ventricular contractility.

Science.gov (United States)

Dickerson, L W; Rodak, D J; Fleming, T J; Gatti, P J; Massari, V J; McKenzie, J C; Gillis, R A

1998-05-28

We hypothesized that selective control of ventricular contractility might be mediated by postganglionic parasympathetic neurons in the cranial medial ventricular (CMV) ganglion plexus located in a fat pad at the base of the aorta. Sinus rate, atrioventricular (AV) conduction (ventricular rate during atrial pacing), and left ventricular contractile force (LV dP/dt during right ventricular pacing) were measured in eight chloralose-anesthetized dogs both before and during bilateral cervical vagus stimulation (20-30 V, 0.5 ms pulses, 15-20 Hz). Seven of these dogs were tested under beta-adrenergic blockade (propranolol, 0.8 mg kg(-1) i.v.). Control responses included sinus node bradycardia or arrest during spontaneous rhythm, high grade AV block or complete heart block, and a 30% decrease in contractility from 2118 +/- 186 to 1526 +/- 187 mm Hg s(-1) (P 0.05) decrease in contractility but still elicited the same degree of sinus bradycardia and AV block (N = 8, P < 0.05). Five dogs were re-tested 3 h after trimethaphan fat pad injection, at which time blockade of vagally-induced negative inotropy was partially reversed, as vagal stimulation decreased LV dP/dt by 19%. The same dose of trimethaphan given either locally into other fat pads (PVFP or IVC-ILA) or systemically (i.v.) had no effect on vagally-induced negative inotropy. Thus, parasympathetic ganglia located in the CMV fat pad mediated a decrease in ventricular contractility during vagal stimulation. Blockade of the CMV fat pad had no effect on vagally-mediated slowing of sinus rate or AV conduction.

Value of the Electrocardiogram as a Predictor of Right Ventricular Dysfunction in Patients With Chronic Right Ventricular Volume Overload.

Science.gov (United States)

Alonso, Pau; Andrés, Ana; Rueda, Joaquín; Buendía, Francisco; Igual, Begoña; Rodríguez, María; Osa, Ana; Arnau, Miguel A; Salvador, Antonio

2015-05-01

Pulmonary regurgitation is a common complication in patients with repaired tetralogy of Fallot or congenital pulmonary stenosis. Electrocardiographic variables have been correlated with parameters used to evaluate right ventricular function. We aimed to analyze the diagnostic value of the width and fragmentation of the electrocardiogram in the identification of patients with right ventricular dysfunction and/or dilation. We selected 107 consecutive patients diagnosed with severe pulmonary insufficiency after repair of pulmonary stenosis or tetralogy of Fallot. The tests included electrocardiography, echocardiography, and magnetic resonance. Each electrocardiogram was analyzed manually to measure QRS duration. We defined QRS fragmentation as the presence of low-voltage waves in the terminal portion of the QRS complex in at least 2 contiguous leads. We found a significant negative correlation between QRS width and right ventricular function, as well as a positive correlation with right ventricular volume. The receiver operating characteristic curve indicated a cut-off point for QRS width of 140ms, which showed good sensitivity for a diagnosis of right ventricular dilation (> 80%) and dysfunction (> 95%). In logistic regression models, a QRS duration > 140ms was found to be the only independent predictor of right ventricular dilation and dysfunction. Electrocardiography is a rapid, widely available, and reproducible tool. QRS width constitutes an independent predictor of the presence of right ventricular dilation and dysfunction. This study is the first to provide a cutoff value for QRS width to screen for right ventricle involvement. Copyright © 2014 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Lone ventricular cardiomyopathy,

African Journals Online (AJOL)

... (I) cardiac catheterisation, including coronary arteriography and pulmonary ... described existence of lone ventricular idiopathic ... spectrum of classic idiopathic dilated cardiomyopathy. ... endomyocardial fibrosis, and from discussions at an.

On-line generation of three-dimensional core power distribution using incore detector signals to monitor safety limits

International Nuclear Information System (INIS)

Jang, Jin Wook; Lee, Ki Bog; Na, Man Gyun; Lee, Yoon Joon

2004-01-01

It is essential in commercial reactors that the safety limits imposed on the fuel pellets and fuel clad barriers, such as the Linear Power Density (LPD) and the Departure from Nucleate Boiling Ratio (DNBR), are not violated during reactor operations. In order to accurately monitor the safety limits of current reactor states, a detailed three-dimensional (3D) core power distribution should be estimated from the in-core detector signals. In this paper, we propose a calculation methodology for detailed 3D core power distribution, using in-core detector signals and core monitoring constants such as the 3D Coupling Coefficients (3DCC), node power fraction, and pin-to-node factors. Also, the calculation method for several core safety parameters is introduced. The core monitoring constants for the real core state are promptly provided by the core design code and on-line MASTER(Multi-purpose Analyzer for Static and Transient Effects of Reactors), coupled with the core monitoring program. Through the plant computer, core state variables, which include reactor thermal power, control rod bank position, boron concentration, inlet moderator temperature, and flow rate, are supplied as input data for MASTER. MASTER performs the core calculation based on the neutron balance equation and generates several core monitoring constants corresponding to the real core state in addition to the expected core power distribution. The accuracy of the developed method is verified through a comparison with the current CECOR method. Because in all the verification calculation cases the proposed method shows a more conservative value than the best estimated value and a less conservative one than the current CECOR and COLSS methods, it is also confirmed that this method secures a greater operating margin through the simulation of the YGN-3 cycle-1 core from the viewpoint of the power peaking factor for the LPD and the pseudo hot pin axial power distribution for the DNBR calculation

Evaluation of in-core neutron flux and temperature field measurements during the second period of power commissioning of the KS-150 reactor

International Nuclear Information System (INIS)

Rana, S.B.; Pecho, J.

1975-01-01

The in-core flux mapping system in the KS-150 reactor using mapping fuel elements with self-powered detectors is described. Experimental data evaluation using the Fourier analysis and determination of important operation parameters from the detectors and temperature field distribution using thermocouples for measuring coolant outlet temperatures and fuel temperatures are given. The DPZ-1 detectors used, mapping fuel elements and the method of signal registration are described. The results of operation of mapping fuel elements during the 2nd period of the KS-150 reactor commissioning are given. (author)

Relação entre Fibrose e Arritmias Ventriculares na Cardiopatia Chagásica sem Disfunção Ventricular

Directory of Open Access Journals (Sweden)

Eduardo Marinho Tassi

2014-06-01

Full Text Available Fundamento: Pacientes com doença de Chagas com alteração segmentar apresentam pior prognóstico independentemente da fração de ejeção ventricular esquerda. A ressonância magnética cardíaca é atualmente o melhor método para detecção de alteração segmentar e para avaliação de fibrose miocárdica. Objetivo: Quantificar a fibrose, por meio do realce tardio, pela ressonância magnética cardíaca, em pacientes com doença de Chagas com fração de ejeção ventricular esquerda preservada ou minimamente comprometida (> 45% e detectar padrões de dependência entre fibrose, alteração segmentar e fração de ejeção ventricular esquerda na presença de arritmia ventricular. Métodos: Foram realizados eletrocardiograma, teste ergométrico, Holter e ressonância magnética cardíaca em 61 pacientes, separados em três grupos: (1 eletrocardiograma normal e ressonância magnética cardíaca sem alteração segmentar; (2 eletrocardiograma alterado e ressonância magnética cardíaca sem alteração segmentar; e (3 ressonância magnética cardíaca com alteração segmentar independentemente de alteração no eletrocardiograma. Resultados: O número de pacientes com arritmia ventricular em relação ao número total de pacientes em cada grupo, a porcentagem de fibrose e a fração de ejeção ventricular esquerda foram, respectivamente: no primeiro grupo, 4/26, 0,74% e 74,34%; no segundo grupo, 4/16, 3,96% e 68,5%; e no terceiro grupo, 11/19, 14,07% e 55,59%. Arritmia ventricular foi encontrada em 31,1% dos pacientes. Aqueles com e sem arritmia ventricular apresentaram fração de ejeção ventricular esquerda média de 59,87% e 70,18%, respectivamente, e fibrose de 11,03% e 3,01%, respectivamente. Das variáveis alteração segmentar, grupos, idade, fração de ejeção ventricular esquerda e fibrose, a última foi a única significativa para a presença de arritmia ventricular, com ponto de corte de 11,78% para massa fibrosada (p < 0

The effect of heart failure and left ventricular assist device treatment on right ventricular mechanics: a computational study.

Science.gov (United States)

Park, Jun I K; Heikhmakhtiar, Aulia Khamas; Kim, Chang Hyun; Kim, Yoo Seok; Choi, Seong Wook; Song, Kwang Soup; Lim, Ki Moo

2018-05-22

Although it is important to analyze the hemodynamic factors related to the right ventricle (RV) after left ventricular assist device (LVAD) implantation, previous studies have focused only on the alteration of the ventricular shape and lack quantitative analysis of the various hemodynamic parameters. Therefore, we quantitatively analyzed various hemodynamic parameters related to the RV under normal, heart failure (HF), and HF incorporated with continuous flow LVAD therapy by using a computational model. In this study, we combined a three-dimensional finite element electromechanical model of ventricles, which is based on human ventricular morphology captured by magnetic resonance imaging (MRI) with a lumped model of the circulatory system and continuous flow LVAD function in order to construct an integrated model of an LVAD implanted-cardiovascular system. To induce systolic dysfunction, the magnitude of the calcium transient function under HF condition was reduced to 70% of the normal value, and the time constant was reduced by 30% of the normal value. Under the HF condition, the left ventricular end systolic pressure decreased, the left ventricular end diastolic pressure increased, and the pressure in the right atrium (RA), RV, and pulmonary artery (PA) increased compared with the normal condition. The LVAD therapy decreased the end-systolic pressure of the LV by 41%, RA by 29%, RV by 53%, and PA by 71%, but increased the right ventricular ejection fraction by 52% and cardiac output by 40%, while the stroke work was reduced by 67% compared with the HF condition without LVAD. The end-systolic ventricular tension and strain decreased with the LVAD treatment. LVAD enhances CO and mechanical unloading of the LV as well as those of the RV and prevents pulmonary hypertension which can be induced by HF.

Echocardiographic left ventricular masses in distance runners and weight lifters

Science.gov (United States)

Longhurst, J. C.; Gonyea, W. J.; Mitchell, J. H.; Kelly, A. R.

1980-01-01

The relationships of different forms of exercise training to left ventricular mass and body mass are investigated by echocardiographic studies of weight lifters, long-distance runners, and comparatively sized untrained control subjects. Left ventricular mass determinations by the Penn convention reveal increased absolute left ventricular masses in long-distance runners and competitive weight lifters with respect to controls matched for age, body weight, and body surface area, and a significant correlation between ventricular mass and lean body mass. When normalized to lean body mass, the ventricular masses of distance runners are found to be significantly higher than those of the other groups, suggesting that dynamic training elevates left ventricular mass compared to static training and no training, while static training increases ventricular mass only to the extent that lean body mass is increased.

THE CLINICAL-SIGNIFICANCE OF CORONARY ANATOMY IN POST-INFARCT PATIENTS WITH LATE SUSTAINED VENTRICULAR-TACHYCARDIA OR VENTRICULAR-FIBRILLATION

NARCIS (Netherlands)

WIESFELD, ACP; CRIJNS, HJGM; HILLEGE, HL; TUININGA, YS; LIE, KI

The role of ischaemia in post-infarct patients with ventricular tachyarrhythmias is not firmly established Using coronary angiography, 82 post-infarct patients with sustained ventricular tachycardia or fibrillation were subclassified into three groups. Fourteen patients (17%) had significant

Malignant ventricular tachycardia in acromegaly: a case report

Directory of Open Access Journals (Sweden)

Zhe An

Full Text Available CONTEXT: In patients with acromegaly, cardiovascular complications are the main cause of death; sudden death has been associated with ventricular tachyarrhythmias. In other patients with life-threatening malignant ventricular tachyarrhythmias, surgical placement of an implantable cardioverter-defibrillator (ICD has proved highly effective in reducing sudden death rates. CASE REPORT: The present article reports the case of a 50-year-old male acromegalic patient who presented symptoms of syncope induced by ventricular tachycardia. An ICD was surgically implanted and a pituitary adenoma, which was responsible for the acromegaly, was completely removed in the same procedure. The surgery was successful and the ventricular arrhythmias were effectively terminated. During six months of follow-up, no documented arrhythmic episodes occurred. CONCLUSION: In patients with acromegaly, malignant ventricular tachyarrhythmia might be effectively controlled by implantation of an ICD and surgical removal of the pituitary adenoma.

Right ventricular function assessed by 2D strain analysis predicts ventricular arrhythmias and sudden cardiac death in patients after acute myocardial infarction

DEFF Research Database (Denmark)

Risum, Niels; Valeur, Nana; Søgaard, Peter

2017-01-01

Aims: Left ventricular function is a well-established predictor of malignant ventricular arrhythmias, but little is known about the importance of right ventricular (RV) function. The aim of this study was to investigate the importance of RV function for prediction of sudden cardiac death (SCD) or...

Reporte del primer caso de implante exitoso de asistencia ventricular izquierda HeartMate II como terapia de destino en Suramérica

Directory of Open Access Journals (Sweden)

Antonio Figueredo

2016-11-01

Full Text Available Se describe el caso de una paciente de sexo femenino de 55 años de edad, con insuficiencia cardiaca congestiva descompensada secundaria a cardiopatía dilatada idiopática y con contraindicación para trasplante cardiaco, en quien se implanta de manera exitosa el primer dispositivo de asistencia ventricular izquierda HeartMate II en Suramérica.

Arrhythmogenic right ventricular dysplasia: A case report

Directory of Open Access Journals (Sweden)

Tessa Negrín Valdés

2015-10-01

Full Text Available Arrhythmogenic right ventricular dysplasia is a heart muscle disease that predominantly affects the right ventricle, bringing about the replacement of normal myocardium with fatty or fibrofatty tissue and causing sudden death in young individuals. Ventricular tachycardia is an important clinical manifestation, although there are reports of right or global heart failure. The diagnosis is confirmed by echocardiography and magnetic resonance imaging. The case of a 65-year-old former smoker, with hypertension and ischemic heart disease, a history of effort syncope symptoms and proven non-sustained ventricular tachycardia, with morphology of left bundle branch block, is reported. Relevant diagnostic studies were performed, and echocardiographic elements which were compatible with arrhythmogenic right ventricular dysplasia were found. Therefore, an implantable cardioverter defibrillator was implanted, after which the patient has had a favorable outcome.

Ventricular repolarization measures for arrhythmic risk stratification

Institute of Scientific and Technical Information of China (English)

Francesco Monitillo; Marta Leone; Caterina Rizzo; Andrea Passantino; Massimo Iacoviello

2016-01-01

Ventricular repolarization is a complex electrical phenomenon which represents a crucial stage in electrical cardiac activity. It is expressed on the surface electrocardiogram by the interval between the start of the QRS complex and the end of the T wave or U wave(QT). Several physiological, pathological and iatrogenic factors can influence ventricular repolarization. It has been demonstrated that small perturbations in this process can be a potential trigger of malignant arrhythmias, therefore the analysis of ventricular repolarization represents an interesting tool to implement risk stratification of arrhythmic events in different clinical settings. The aim of this review is to critically revise the traditional methods of static analysis of ventricular repolarization as well as those for dynamic evaluation, their prognostic significance and the possible application in daily clinical practice.

The influence of type 2 diabetes and gender on ventricular repolarization dispersion in patients with sub-clinic left ventricular diastolic dysfunction

Science.gov (United States)

Jani, Ylber; Kamberi, Ahmet; Xhunga, Sotir; Pocesta, Bekim; Ferati, Fatmir; Lala, Dali; Zeqiri, Agim; Rexhepi, Atila

2015-01-01

Objective: To assess the influence of type 2 DM and gender, on the QT dispersion, Tpeak-Tend dispersion of ventricular repolarization, in patients with sub-clinic left ventricular diastolic dysfunction of the heart. Background: QT dispersion, that reflects spatial inhomogeneity in ventricular repolarization, Tpeak-Tend dispersion, this on the other hand reflects transmural inhomogeneity in ventricular repolarization, that is increased in an early stage of cardiomyopathy, and in patients with left ventricular diastolic dysfunction, as well. The left ventricular diastolic dysfunction, a basic characteristic of diabetic heart disease (diabetic cardiomyopathy), that developes earlier than systolic dysfunction, suggests that diastolic markers might be sensitive for early cardiac injury. It is also demonstrated that gender has complex influence on indices of myocardial repolarization abnormalities such as QT interval and QT dispersion. Material and methods: We performed an observational study including 300 diabetic patients with similar epidemiological-demographic characteristics recruited in our institution from May 2009 to July 2014, divided into two groups. Demographic and laboratory echocardiographic data were obtained, twelve lead resting electrocardiography, QT, QTc, Tpeak-Tend-intervals and dispersion, were determined manually, and were compared between various groups. For statistical analysis a t-test, X2 test, and logistic regression are used according to the type of variables. A p value <0.05 was considered statistically significant for a confidence interval of 95%. Results: QTc max. interval, QTc dispersion and Tpeak-Tend dispersion, were significantly higher in diabetic group with subclinical LV (left ventricular) diastolic dysfunction, than in diabetic group with normal left ventricular diastolic function (445.24±14.7 ms vs. 433.55±14.4 ms, P<0.000; 44.98±18.78 ms vs. 32.05±17.9 ms, P<0.000; 32.60±1.6 ms vs. 17.46±2.0 ms, P<0.02. Prolonged QTc max

Left ventricular mass in male adolescent athletes and non-athletes

Directory of Open Access Journals (Sweden)

Erling David Kaunang

2014-10-01

Full Text Available Background Systematic exercise leads to increased left ventricular mass, which may be misleading in a differential diagnosis of heart disease in athletes (physiologic hypertrophy versus pathologic hypertrophy. T he cause of left ventricular hypertrophy is an important risk factor in the morbidity and mortality of cardiovascular diseases. Objective To compare left ventricular mass and left ventricular hypertrophy in male adolescent athletes and non-athletes. Methods We conducted a cross-sectional, analytic study, from September to December 2012 in male adolescents aged 15-18 years. The case group included athletes from the Bina Taruna Football Club Manado, while the control group included non-athlete adolescents. All subjects underwent history-taking, physical examinations and further supporting examinations. Left ventricular mass was measured by cardiovascular echocardiography (Esaote Mylab 4.0 and calculated based on a formula. Left ventricular hypertrophy was defined as left ventricular mass of > 134 g/m2 body surface area. Results Subjects' mean left ventricular masses were 359.69 (SD 188.4; 95%CI 283.58 to 435.81 grams in the athlete group and 173.04 (SD 50.69; 95%CI 152.56 to 103.51 grams in the non· athlete group, a statistically significant difference (P=0.0001. Ventricular hypertrophy was found 76.9% compared to 11.5% in  the non-athlete group (P= 0.0001. Conclusion Left ventricular mass in athletes is bigger than in non-athletes. In addition, left ventricular hypertrophy is more cornmon in male adolescent athletes than in non-athletes.

In-core Instrument Subcritical Verification (INCISV) - Core Design Verification Method - 358

International Nuclear Information System (INIS)

Prible, M.C.; Heibel, M.D.; Conner, S.L.; Sebastiani, P.J.; Kistler, D.P.

2010-01-01

According to the standard on reload startup physics testing, ANSI/ANS 19.6.1, a plant must verify that the constructed core behaves sufficiently close to the designed core to confirm that the various safety analyses bound the actual behavior of the plant. A large portion of this verification must occur before the reactor operates at power. The INCISV Core Design Verification Method uses the unique characteristics of a Westinghouse Electric Company fixed in-core self powered detector design to perform core design verification after a core reload before power operation. A Vanadium self powered detector that spans the length of the active fuel region is capable of confirming the required core characteristics prior to power ascension; reactivity balance, shutdown margin, temperature coefficient and power distribution. Using a detector element that spans the length of the active fuel region inside the core provides a signal of total integrated flux. Measuring the integrated flux distributions and changes at various rodded conditions and plant temperatures, and comparing them to predicted flux levels, validates all core necessary core design characteristics. INCISV eliminates the dependence on various corrections and assumptions between the ex-core detectors and the core for traditional physics testing programs. This program also eliminates the need for special rod maneuvers which are infrequently performed by plant operators during typical core design verification testing and allows for safer startup activities. (authors)

Detection of premature ventricular contractions on a ventricular electrocardiogram for patients with left ventricular assist devices.

Science.gov (United States)

Park, Sung Min; Lee, Jin Hong; Choi, Seong Wook

2014-12-01

The ventricular electrocardiogram (v-ECG) was developed for long-term monitoring of heartbeats in patients with a left ventricular assist device (LVAD) and does not normally have the functionality necessary to detect additional heart irregularities that can progress to critical arrhythmias. Although the v-ECG has the benefits of physiological optimization and counterpulsation control, when abnormal heartbeats occur, the v-ECG does not show the distinct abnormal waveform that enables easy detection of an abnormal heartbeat among normal heartbeats on the conventional ECG. In this study, the v-ECGs of normal and abnormal heartbeats are compared with each other with respect to peak-to-peak voltage, area, and maximal slopes, and a new method to detect abnormal heartbeats is suggested. In a series of animal experiments with three porcine models (Yorkshire pigs weighing 30-40 kg), a v-ECG and conventional ECG were taken simultaneously during LVAD perfusion. Clinical experts found 104 abnormal heartbeats from the saved conventional ECG data and confirmed that the other 3159 heartbeats were normal. Almost all of the abnormal heartbeats were premature ventricular contractions (PVCs), and there was short-term tachycardia for 3 s. A personal computer was used to automatically detect abnormal heartbeats with the v-ECG according to the new method, and its results were compared with the clinicians' results. The new method found abnormal heartbeats with 90% accuracy, and less than 15% of the total PVCs were missed. Copyright © 2014 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Development and manufacturing of special fission chambers for in-core measurement requirements in nuclear reactors

Energy Technology Data Exchange (ETDEWEB)

Geslot, B.; Berhouet, F.; Oriol, L.; Breaud, S.; Jammes, C.; Filliatre, P.; Villard, J. F. [CEA, DEN, Dosimetry Command Control and Instrumentation Laboratory, F-13109 Saint-Paul-lez-Durance (France)

2009-07-01

The Dosimetry Command control and Instrumentation Laboratory (LDCI) at CEA/Cadarache is specialized in the development, design and manufacturing of miniature fission chambers (from 8 mm down to 1.5 mm in diameter). The LDCI fission chambers workshop specificity is its capacity to manufacture and distribute special fission chambers with fissile deposits other than U{sup 235} (typically Pu{sup 242}, Np{sup 237}, U{sup 238}, Th{sup 232}). We are also able to define the characteristics of the detector for any in-core measurement requirements: sensor geometry, fissile deposit material and mass, filling gas composition and pressure, operating mode (pulse, current or Campbelling) with associated cable and electronics. The fission chamber design relies on numerical simulation and modeling tools developed by the LDCI. One of our present activities in fission chamber applications is to develop a fast neutron flux instrumentation using Campbelling mode dedicated to measurements in material testing reactors. (authors)

Evaluation of left ventricular function by cardiac CT

International Nuclear Information System (INIS)

Naito, Hiroaki; Kozuka, Takahiro

1982-01-01

Left ventricular function was evaluated by CT, which was compared with the data of left ventriculography for various cardiac diseases. The end diastolic volume of the left ventricle can be readily computed from CT, with a satisfactory correlation with that of left ventriculography (r = 0.95). The left ventricular ejection fraction, calculated from the areal ratio of the left ventricular lumen in end-diastolic imaging to that in end-sytolic imaging, also roughly reflects left ventricular contractile function, but shows correlation with left ventriculography by only r = 0.79. Although the cardiac output is not sensitive for functional evaluation, it can be directly calculated by means of dynamic scanning and shows a satisfactory correlation with the ear piece pigment dilution (r = 0.85). Evaluation of left ventricular function by CT shows a high precision in comparison with left ventriculography, but still lacks temporal resolving power. (Chiba, N.)

[Ventricular tachycardia in a patient with rate-responsive cardiac pacemaker].

Science.gov (United States)

Himbert, C; Lascault, G; Tonet, J; Coutte, R; Busquet, P; Frank, R; Grosgogeat, Y

1992-11-01

The authors report a case of syncopal ventricular tachycardia in a patient with a respiratory-dependent rate responsive pacemaker, followed-up for valvular heart disease with severe left ventricular dysfunction and sustained atrial and ventricular arrhythmias. The introduction of low dose betablocker therapy with reinforcement of the treatment of cardiac failure controlled the ventricular arrhythmia, after suppression of the data responsive function had been shown to be ineffective. The authors discuss the role of the rate responsive function in the triggering of the ventricular tachycardias.

Automated in-core image generation from video to aid visual inspection of nuclear power plant cores

Energy Technology Data Exchange (ETDEWEB)

Murray, Paul, E-mail: paul.murray@strath.ac.uk [Department of Electronic and Electrical Engineering, University of Strathclyde, Technology and Innovation Centre, 99 George Street, Glasgow, G1 1RD (United Kingdom); West, Graeme; Marshall, Stephen; McArthur, Stephen [Dept. Electronic and Electrical Engineering, University of Strathclyde, Royal College Building, 204 George Street, Glasgow G1 1XW (United Kingdom)

2016-04-15

Highlights: • A method is presented which improves visual inspection of reactor cores. • Significant time savings are made to activities on the critical outage path. • New information is extracted from existing data sources without additional overhead. • Examples from industrial case studies across the UK fleet of AGR stations. - Abstract: Inspection and monitoring of key components of nuclear power plant reactors is an essential activity for understanding the current health of the power plant and ensuring that they continue to remain safe to operate. As the power plants age, and the components degrade from their initial start-of-life conditions, the requirement for more and more detailed inspection and monitoring information increases. Deployment of new monitoring and inspection equipment on existing operational plant is complex and expensive, as the effect of introducing new sensing and imaging equipment to the existing operational functions needs to be fully understood. Where existing sources of data can be leveraged, the need for new equipment development and installation can be offset by the development of advanced data processing techniques. This paper introduces a novel technique for creating full 360° panoramic images of the inside surface of fuel channels from in-core inspection footage. Through the development of this technique, a number of technical challenges associated with the constraints of using existing equipment have been addressed. These include: the inability to calibrate the camera specifically for image stitching; dealing with additional data not relevant to the panorama construction; dealing with noisy images; and generalising the approach to work with two different capture devices deployed at seven different Advanced Gas Cooled Reactor nuclear power plants. The resulting data processing system is currently under formal assessment with a view to replacing the existing manual assembly of in-core defect montages. Deployment of the

Hypertrophic cardiomyopathy with mid-ventricular obstruction and apical aneurysm

Directory of Open Access Journals (Sweden)

N.D. Oryshchyn

2016-11-01

Full Text Available A case report of apical left ventricular aneurysm in patient with hypertrophic cardiomyopathy with mid-ventricular obstruction (diagnosis and surgical treatment is presented. We revealed apical aneurysm and mid-ventricular obstruction during echocardiography and specified anatomical characteristics of aneurysm during computer tomography. There was no evidence of obstructive coronary artery disease during coronary angiography. Taking into consideration multiple cerebral infarcts, aneurysm resection and left ventricular plastics was performed. Electronic microscopy of myocardium confirmed the diagnosis of hypertrophic cardiomyopathy.

In-core nuclear fuel management optimization of VVER1000 using perturbation theory

International Nuclear Information System (INIS)

Hosseini, Mohammad; Vosoughi, Naser

2011-01-01

In-core nuclear fuel management is one of the most important concerns in the design of nuclear reactors. The two main goals in core fuel loading pattern design optimization are maximizing the core effective multiplication factor in order to extract the maximum energy, and keeping the local power peaking factor lower than a predetermined value to maintain fuel integrity. Because of the numerous possible patterns of the fuel assemblies in the reactor core, finding the best configuration is so important and complex. Different methods for optimization of fuel loading pattern in the core have been introduced so far. In this study, a software is programmed in C ⧣ language to find an order of the fuel loading pattern of the VVER-1000 reactor core using the perturbation theory. Our optimization method is based on minimizing the radial power peaking factor. The optimization process lunches by considering the initial loading pattern and the specifications of the fuel assemblies which are given as the input of the software. It shall be noticed that the designed algorithm is performed by just shuffling the fuel assemblies. The obtained results by employing the mentioned method on a typical reactor reveal that this method has a high precision in achieving a pattern with an allowable radial power peaking factor. (author)

Modernized accurate methods for processing of in-core measurement signals in WWER reactors

International Nuclear Information System (INIS)

Polak, T.

1996-01-01

Utilization of the new accurate WIMS-KAERI library (WIMKAL-88) to generate the following characteristics for Rhodium SPND: Sensitivity depletion law by high (approx= 75%) burnup of emitter; influence of burnup-history on depletion law course; influence of neutron spectrum change on Rh-SPND sensitivity caused by change of fuel enrichment, fuel burnup, moderator temperature, concentration of boracid, central pin power rate and concentration of Xe 135 ; generating and experimental testing of Rh-SPND signal to linear pin power rate and signal to neutron flux conversion factors. Rh-SPND instrumentation optimization (reduction) related to safety and operational aspects as needed for 3D power surveillance in WWER-1000 reactors. Analysis of SPND reduction from 64x7 to 46x7 by method of Shannon information entropy optimization. Influence of reduction on accuracy of 3D power distribution reconstruction. Physical methods of 3D power distribution unfolding in new modernized on-line I and C system in NPP J. Bohunice with in-core measurements according to 210 thermocouples and 36x7 Rh-SPNDs. Program system TOPRE under QNX operating system network in FORTRAN 77, neutronic background calculations by macrocode MOBY-DICK. (author). 10 refs, 6 figs, 7 tabs

Bidirectional ventricular tachycardia of unusual etiology

Directory of Open Access Journals (Sweden)

Praloy Chakraborty

2015-11-01

Full Text Available Bidirectional ventricular tachycardia (BDVT is a rare form of ventricular arrhythmia, characterized by changing QRS axis of 180 degrees. Digitalis toxicity is considered as commonest cause of BDVT; other causes include aconite toxicity, myocarditis, myocardial infarction, metastatic cardiac tumour and cardiac channelopathies. We describe a case of BDVT in a patient with Anderson-Tawil syndrome.

Evaluation of ventricular function in patients with coronary artery disease

International Nuclear Information System (INIS)

Rocco, T.P.; Dilsizian, V.; Fischman, A.J.; Strauss, H.W.

1989-01-01

The recent expansion of interventional cardiovascular technologies has stimulated a concomitant expansion of noninvasive cardiac studies, both to assist in diagnosis and to evaluate treatment outcomes. Radionuclide ventricular function studies provide a reliable, reproducible means to quantify global left ventricular systolic performance, a critical determinant of prognosis in patients with cardiovascular disease. In addition, the ability to evaluate regional left ventricular wall motion and to assess ventricular performance during exercise have secured a fundamental role for such studies in the screening and treatment of patients with coronary artery disease. Radionuclide techniques have been extended to the evaluation of left ventricular relaxation/filling events, left ventricular systolic/diastolic function in the ambulatory setting, and with appropriate technical modifications, to the assessment of right ventricular performance at rest and with exercise. As a complement to radionuclide perfusion studies, cardiac blood-pool imaging allows for thorough noninvasive description of cardiac physiology and function in both normal subjects and in patients with a broad range of cardiovascular diseases. 122 references

Ventricular Septal Dissection Complicating Inferior Wall Myocardial Infarction

Directory of Open Access Journals (Sweden)

Lindsey Kalvin

2017-01-01

Full Text Available Postmyocardial infarction ventricular septal defect is an increasingly rare mechanical complication of acute myocardial infarction. We present a case of acute myocardial infarction from right coronary artery occlusion that developed hypotension and systolic murmur 12 hours after successful percutaneous coronary intervention. Although preoperative imaging suggested a large ventricular septal defect and a pseudoaneurysm, intraoperative findings concluded a serpiginous dissection of the ventricular septum. The imaging technicalities are discussed.

Effect of chronic right ventricular apical pacing on left ventricular function.

Science.gov (United States)

O'Keefe, James H; Abuissa, Hussam; Jones, Philip G; Thompson, Randall C; Bateman, Timothy M; McGhie, A Iain; Ramza, Brian M; Steinhaus, David M

2005-03-15

The determinants of change in left ventricular (LV) ejection fraction (EF) over time in patients with impaired LV function at baseline have not been clearly established. Using a nuclear database to assess changes in LV function over time, we included patients with a baseline LVEF of 25% to 40% on a gated single-photon emission computed tomographic study at rest and only if second-gated photon emission computed tomography performed approximately 18 months after the initial study showed an improvement in LVEF at rest of > or =10 points or a decrease in LVEF at rest of > or =7 points. In all, 148 patients qualified for the EF increase group and 59 patients for the EF decrease group. LVEF on average increased from 33 +/- 4% to 51 +/- 8% in the EF increase group and decreased from 35 +/- 4% to 25 +/- 5% in the EF decrease group. The strongest multivariable predictor of improvement of LVEF was beta-blocker therapy (odds ratio 3.9, p = 0.002). The strongest independent predictor of LVEF decrease was the presence of a permanent right ventricular apical pacemaker (odds ratio 6.6, p = 0.002). Thus, this study identified beta-blocker therapy as the major independent predictor for improvement in LVEF of > or =10 points, whereas a permanent pacemaker (right ventricular apical pacing) was the strongest predictor of a LVEF decrease of > or =7 points.

The helical ventricular myocardial band of Torrent-Guasp.

Science.gov (United States)

Kocica, Mladen J; Corno, Antonio F; Lackovic, Vesna; Kanjuh, Vladimir I

2007-01-01

We live in an era of substantial progress in understanding myocardial structure and function at genetic, molecular, and microscopic levels. Yet, ventricular myocardium has proven remarkably resistant to macroscopic analyses of functional anatomy. Pronounced and practically indefinite global and local structural anisotropy of its fibers and other ventricular wall constituents produces electrical and mechanical properties that are nonlinear, anisotropic, time varying, and spatially inhomogeneous. The helical ventricular myocardial band of Torrent-Guasp is a revolutionary new concept in understanding global, 3-dimensional, functional architecture of the ventricular myocardium. This concept defines the principal, cumulative vectors, integrating the tissue architecture (ie, form) and net forces developed (ie, function) within the ventricular mass. The primary purpose of this review is to emphasize the importance of this concept, in the light of collaborative efforts to establish an integrative approach, defining ventricular form and function by linking across multiple scales of biological organization, as explained in the ongoing Physiome project. Because one of the most important scientific missions in this century is integration of basic research with clinical medicine, we believe that this knowledge is not of merely academic importance, but is also the essential prerequisite in clinical evaluation and treatment of different heart diseases.

Clinical studies on myocardial perfusion imaging in patients with right ventricular overload

International Nuclear Information System (INIS)

Abo, Kenji; Yamagata, Takashi; Nakajima, Masao; Fujita, Kimiaki; Morita, Nobuo

1979-01-01

Patients with heart disease which had been clinically diagnosed underwent 201 Tl myocardial perfusion imaging. The thickness of right ventricular wall measured from original images was directly proportional to systolic pressure of the right ventricle measured by cardiac catheterization, and 201 Tl activity in the right ventricle was more directly proportional to systolic pressure of the right ventricle. Imaging patterns of various diseases were also described. Images of patients with hypertrophic cardiomyopathy revealed that right ventricular wall was thin and right ventricular cavity was small, but the thickness of septal wall and left ventricular wall were maximal. Images of patients with mitral insufficiency revealed that the thickness of right ventricular wall, septal wall, and left ventricular wall was medium, and the right ventricular cavity was smaller than the left ventricular cavity. Images of patients with congestive cardiomyopathy and congestive cardiac failure showed that enlargement of both ventricular cavities was disproportionate to the thickness of each wall. Images of patients with arterial septal defect revealed that the thickness of each wall was comparatively normal, the right ventricular cavity was maximal, and the left ventricular cavity was minimal. Images of patients with primary pulmonary hypertention, pulmonary stenosis and tetralogy of Fallot in whom pressure overload was recognized revealed severe thickenings of right ventricular wall, moderate enlargement of the right ventricle, small left ventricle, and thin left ventricular wall. (Tsunoda, M.)

Bundle of measures for external cerebral ventricular drainage-associated ventriculitis.

Science.gov (United States)

Chatzi, Maria; Karvouniaris, Marios; Makris, Demosthenes; Tsimitrea, Eleni; Gatos, Charalampos; Tasiou, Anastasia; Mantzarlis, Kostas; Fountas, Kostas N; Zakynthinos, Epaminondas

2014-01-01

To assess the prevalence and outcome of external cerebral ventricular drainage-associated ventriculitis in neurocritical patients before and after the implementation of a bundle of external cerebral ventricular drainage-associated ventriculitis control measures. Clinical prospective case series. University Hospital of Larissa, Greece. Consecutive patients were recruited from the ICU of the hospital. Patient inclusion criteria included presence of external ventricular drainage and ICU stay more than 48 hours. The bundle of external cerebral ventricular drainage-associated ventriculitis control measures included 1) reeducation of ICU personnel on issues of infection control related to external cerebral ventricular drainage, 2) meticulous intraventricular catheter handling, 3) cerebrospinal fluid sampling only when clinically necessary, and 4) routine replacement of the drainage catheter on the seventh drainage day if the catheter was still necessary. The bundle was applied after an initial period (preintervention) where standard policy for external cerebral ventricular drainage-associated ventriculitis was established. External cerebral ventricular drainage-associated ventriculitis prevalence, external cerebral ventricular drainage-associated ventriculitis events per 1,000 drainage days (drain-associated infection rate), length of ICU stay, Glasgow Outcome Scale at 6 months, and risk factors for external cerebral ventricular drainage-associated ventriculitis. Eighty-two patients entered the study in the preintervention period and 57 patients during the intervention period. During the preintervention and intervention period, external cerebral ventricular drainage-associated ventriculitis prevalence was 28% and 10.5% (p = 0.02) and drain-associated infection rate was 18 and 7.1, respectively (p = 0.0001); mean (95% CI) length of ICU stay in patients who presented external cerebral ventricular drainage-associated ventriculitis was 44.4 days (36.4-52.4 d), whereas mean

Does in-hospital ventricular fibrillation affect prognosis after myocardial infarction?

DEFF Research Database (Denmark)

Jensen, G V; Torp-Pedersen, C; Hildebrandt, P

1997-01-01

with ventricular fibrillation in time intervals, indicated that the importance of ventricular fibrillation for risk of death was exhausted during the initial 60 days after infarction. CONCLUSION: Ventricular fibrillation is associated with an independent increased risk of death within 0-60 days after infarction......AIM: The aim of this study was to estimate the prognostic information to be gained from ventricular fibrillation in patients with myocardial infarction. METHODS AND RESULTS: We studied 4259 consecutive patients with myocardial infarction admitted to one centre in 1977-1988. Five hundred and twenty......-eight (12.4%) of the patients had ventricular fibrillation in hospital. The following risk factors were included in multivariate models to estimate their importance for 30-day and long-term (median 7 year) prognosis: age, gender, ventricular fibrillation, congestive heart failure, pulmonary oedema...

Evaluation of left ventricular function using digital subtraction ventriculography

International Nuclear Information System (INIS)

Yiannikas, J.; Detrano, R.

1986-01-01

Digital subtraction ventriculography following injections of contrast via peripheral veins provides excellent images to assess left ventricular function. The images are essentially identical to those following DCV, but allow more uniform mixing of contrast in the left ventricular chamber. Furthermore, few, if any, cardiac arrhythmias occur, hence obviating difficulties that arise from DCV. The spatial resolution of the method is such that regional wall motion assessment of ventricular function is more accurate than that of other noninvasive imaging methods. The use of video-densitometry allows accurate assessment of left ventricular function even when the left ventricular cavity is nonsymmetrically deformed and aneurysmal. In the setting of the cardiac catheterization laboratory, digital ventriculography may provide a safer means of assessing left ventricular function when critical coronary or myocardial disease is present and allows multiple assessments of ventricular function during the same study. Although excellent correlations with standard ventriculography have been noted by all workers, significant discrepancies still exist in individual patients, particularly in the calculations of end diastolic volumes. In the authors experience and in those of most workers, the largest discrepancies existed in patients in whom suboptimal studies are included for analysis. The most frequent reason for the occasional suboptimal study as with all digital subtraction work is the misregistration that results from motion

Arrhythmogenic right ventricular cardiomyopathy: contribution of different electrocardiographic techniques.

Science.gov (United States)

Moreira, Davide; Delgado, Anne; Marmelo, Bruno; Correia, Emanuel; Gama, Pedro; Pipa, João; Nunes, Luís; Santos, Oliveira

2014-04-01

Arrhythmogenic right ventricular cardiomyopathy, also known as arrhythmogenic right ventricular dysplasia, is a condition in which myocardium is replaced by fibrous or fibrofatty tissue, predominantly in the right ventricle. It is clinically characterized by potentially lethal ventricular arrhythmias, and is a leading cause of sudden cardiac death. Its prevalence is not known exactly but is estimated at approximately 1:5000 in the adult population. Diagnosis can be on the basis of structural and functional alterations of the right ventricle, electrocardiographic abnormalities (including depolarization and repolarization alterations and ventricular arrhythmias) and family history. Diagnostic criteria facilitate the recognition and interpretation of non-specific clinical features of this disease. The authors present a case in which the diagnosis of arrhythmogenic right ventricular cardiomyopathy was prompted by the suspicion of right ventricular disease on transthoracic echocardiography. This was confirmed by detection of epsilon waves on analysis of the ECG, which generally go unnoticed but in this case were the key to the diagnosis. Their presence was also shown by non-conventional ECG techniques such as modified Fontaine ECG. The course of the disease culminated in the occurrence of ventricular tachycardia, which prompted placement of an implantable cardioverter-defibrillator. Copyright © 2013 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

A case of short-coupled premature ventricular beat-induced ventricular fibrillation with early repolarization in the inferolateral leads

Directory of Open Access Journals (Sweden)

Hidekazu Kondo, MD

2015-02-01

Full Text Available This case report describes a 19-year-old man with early repolarization (ER in the inferolateral leads and a normal QT interval who survived a cardiac arrest that was likely related to polymorphic ventricular tachycardia (VT. Electrocardiograms (ECGs also showed unifocal premature ventricular beats (PVBs with a relatively narrow QRS duration. A Holter ECG documented occasional short-coupled PVBs following non-sustained VTs. Pharmacological stress testing was also performed to assess the effects of anti-arrhythmic drugs on ER (the J wave and PVBs. We performed successful radiofrequency catheter ablation to prevent the recurrence of ventricular fibrillation after cardioverter-defibrillator implantation.

The management of ventricular dysrhythmia in aconite poisoning.

Science.gov (United States)

Coulson, James M; Caparrotta, Thomas M; Thompson, John P

2017-06-01

Aconite poisoning is relatively rare but is frequently complicated by ventricular dysrhythmias, which may be fatal. Molecular basis of aconite alkaloid ventricular arrhythmogenicity: Aconite exerts its toxic effects due to the presence of an admixture of alkaloids present in all parts of the plant. The major target of these aconite alkaloids is the fast voltage-gates sodium channel, where they cause persistent activation. This blockade of the channel in the activated state promotes automaticity within the ventricular myocardium and the generation of ventricular arrhythmias. Aconitine-induced arrhythmias: Aconite alkaloids are known to cause many different types of disturbance of heart rhythm. However, this focused review specifically looks at ventricular rhythm disturbances, namely ventricular ectopy, ventricular tachycardia, torsades des pointes and ventricular fibrillation. The objective of this review was to identify the outcome of anti-dysrhythmic strategies from animal studies and case reports in humans in order to guide the management of ventricular dysrhythmias in aconite poisoning in humans. A review of the literature in English was conducted in PubMed and Google Scholar from 1966 to July 2016 using the search terms "aconite/aconitine"; "aconite/aconitine + poisoning" and "aconite/aconitine + dysrhythmia". 168 human case-reports and case-series were identified by these searches, of which 103 were rejected if exposure to aconite did not result in ventricular dysrhythmias, if it was uncertain as to whether aconite had been ingested, if other agents were co-ingested, if there was insufficient information to determine the type of treatments administered or if there was insufficient information to determine outcome. Thus, 65 case reports of probable aconite poisoning that resulted in ventricular dysrhythmias were identified. Toxicokinetic data in aconite poisoning: Data were only available in three papers; the presence of ventricular rhythm disturbances

Muscular anatomy of the human ventricular folds.

Science.gov (United States)

Moon, Jerald; Alipour, Fariborz

2013-09-01

Our purpose in this study was to better understand the muscular anatomy of the ventricular folds in order to help improve biomechanical modeling of phonation and to better understand the role of these muscles during phonatory and nonphonatory tasks. Four human larynges were decalcified, sectioned coronally from posterior to anterior by a CryoJane tape transfer system, and stained with Masson's trichrome. The total and relative areas of muscles observed in each section were calculated and used for characterizing the muscle distribution within the ventricular folds. The ventricular folds contained anteriorly coursing thyroarytenoid and ventricularis muscle fibers that were in the lower half of the ventricular fold posteriorly, and some ventricularis muscle was evident in the upper and lateral portions of the fold more anteriorly. Very little muscle tissue was observed in the medial half of the fold, and the anterior half of the ventricular fold was largely devoid of any muscle tissue. All 4 larynges contained muscle bundles that coursed superiorly and medially through the upper half of the fold, toward the lateral margin of the epiglottis. Although variability of expression was evident, a well-defined thyroarytenoid muscle was readily apparent lateral to the arytenoid cartilage in all specimens.

Haemodynamic effects of dual-chamber pacing versus ventricular pacing during a walk test in patients with depressed or normal left ventricular function

Energy Technology Data Exchange (ETDEWEB)

Ferro, Adele; Salvatore, Marco; Cuocolo, Alberto [University Federico II, Department of Biomorphological and Functional Sciences, Institute of Biostructure and Bioimages of the National Council of Research, Naples (Italy); Duilio, Carlo; Santomauro, Maurizio [University Federico II, Department of Clinical Medicine, Cardiovascular and Immunological Sciences, Naples (Italy)

2005-09-01

Dual-chamber rate-modulated pacing provides haemodynamic benefits compared with ventricular pacing at rest, but it is unclear whether this also holds true during physical exercise in patients with heart failure. This study assessed the haemodynamic response to a walk test during dual-chamber pacing and ventricular pacing in patients with depressed or normal left ventricular (LV) function. Twelve patients with an LV ejection fraction <50% and 11 patients with an LV ejection fraction {>=}50% underwent two randomised 6-min walk tests under dual-chamber rate-modulated pacing and ventricular pacing at a fixed rate of 70 beats/min. All patients had a dual-chamber pacemaker implanted for complete heart block. LV function was monitored by a radionuclide ambulatory system. In patients with depressed LV function, the change from dual-chamber pacing to ventricular pacing induced a decrease in end-systolic volume at the peak of the walk test (P<0.05), with no difference in end-diastolic volume. As a consequence, higher increases in LV ejection fraction (P<0.0001) and stroke volume (P<0.01) were observed during ventricular pacing. No difference in cardiac output was found between the two pacing modes. In patients with normal LV function, the change from dual-chamber pacing to ventricular pacing induced a significant decrease in cardiac output (P<0.005 at rest and P<0.05 at the peak of the walk test). Compared with dual-chamber rate-modulated pacing, ventricular pacing improves cardiac function and does not affect cardiac output during physical activity in patients with depressed LV function, whereas it impairs cardiac output in those with normal function. (orig.)

Haemodynamic effects of dual-chamber pacing versus ventricular pacing during a walk test in patients with depressed or normal left ventricular function

International Nuclear Information System (INIS)

Ferro, Adele; Salvatore, Marco; Cuocolo, Alberto; Duilio, Carlo; Santomauro, Maurizio

2005-01-01

Dual-chamber rate-modulated pacing provides haemodynamic benefits compared with ventricular pacing at rest, but it is unclear whether this also holds true during physical exercise in patients with heart failure. This study assessed the haemodynamic response to a walk test during dual-chamber pacing and ventricular pacing in patients with depressed or normal left ventricular (LV) function. Twelve patients with an LV ejection fraction <50% and 11 patients with an LV ejection fraction ≥50% underwent two randomised 6-min walk tests under dual-chamber rate-modulated pacing and ventricular pacing at a fixed rate of 70 beats/min. All patients had a dual-chamber pacemaker implanted for complete heart block. LV function was monitored by a radionuclide ambulatory system. In patients with depressed LV function, the change from dual-chamber pacing to ventricular pacing induced a decrease in end-systolic volume at the peak of the walk test (P<0.05), with no difference in end-diastolic volume. As a consequence, higher increases in LV ejection fraction (P<0.0001) and stroke volume (P<0.01) were observed during ventricular pacing. No difference in cardiac output was found between the two pacing modes. In patients with normal LV function, the change from dual-chamber pacing to ventricular pacing induced a significant decrease in cardiac output (P<0.005 at rest and P<0.05 at the peak of the walk test). Compared with dual-chamber rate-modulated pacing, ventricular pacing improves cardiac function and does not affect cardiac output during physical activity in patients with depressed LV function, whereas it impairs cardiac output in those with normal function. (orig.)

Left ventricular mass in borderline hypertension assessed by echo cardiography

International Nuclear Information System (INIS)

Mezzasalma, L.; Ghione, S.; Palonebo, C.

1989-01-01

The relationship between clinical measurement of blood pressure (BP) and left ventricular hypertrophy in arterial hypertension appears to be weak in most studies. On the contrary, stronger correlations with target organ damage in general, and left ventricular hypertrophy in particular, have been reported for blood pressure measurements obtained by ambulatory monitoring; this finding may indicate a possible role for blood pressure response to naturally occurring stresses in determining left ventricular hypertrophy. Aim of this study was to investigate, in 18 patients with borderline arterial hypertension, the relationships between echocardiographically assessed left ventricular mass and, respectively, casual BP and BP responses to some standardized stress tests. Only three patients had a diastolic wall thickness of the interventricular septum and of the posterior wall ≥1.2 cm and none had a pathologically increased left ventricular mass index. The following statistically significant correlations were found: casual diastolic BP vs. left ventricular mass index (r=0.53, p<0.02), systolic BP response to bicycle exercise test vs. left ventricular mass index (r=0.55, p<0.05). Multiple regression analysis showed that almost fifty percent of the variability of left ventricular mass index could be predicted by these two BP measurements. These findings suggest that besides the chronically increased afterload, also the transient hypertensive responses to naturally occuring physical stresses may have a role in determining the extent of cardiac structural changes in borderline hypertensive patients. In addition, they indicate a direct relation between left ventricular mass and blood pressure levels also in borderline hypertension, as previously shown for established hypertension, despite the fact that left ventricular hypertrophy represents only an occasional finding in early stages of hypertension

Risk factors and predictors of Torsade de pointes ventricular tachycardia in patients with left ventricular systolic dysfunction receiving Dofetilide

DEFF Research Database (Denmark)

Pedersen, Henriette Sloth; Elming, Hanne; Seibaek, Marie

2007-01-01

The purpose of this study was to identify risk factors of Torsade de pointes (TdP) ventricular tachycardia in patients medicated with a class III antiarrhythmic drug (dofetilide) and left ventricular systolic dysfunction with heart failure (HF) or recent myocardial infarction (MI). The 2 Danish...

Left ventricular systolic and diastolic function in hyperthyroidism

International Nuclear Information System (INIS)

Friedman, M.J.; Okada, R.D.; Ewy, G.A.; Hellman, D.J.

1982-01-01

In order to assess the effect of hyperthyroidism on systolic and diastolic function of the left ventricle, M-mode echocardiograms and systolic time intervals were obtained in 13 patients while they were clinically hyperthyroid and again when they were euthyroid following radioactive iodine therapy. Echocardiographic tracings of the septum and left ventricular posterior wall were digitized and analyzed to provide the maximum velocity of shortening and maximum velocity of lengthening. These velocities were normalized for left ventricular diastolic dimension. The left ventricular minor axis fractional shortening and the normalized maximum velocity of shortening were both increased during the hyperthyroid state. The normalized maximum velocity of lengthening, a measure of diastolic left ventricular function, was also increased during the hyperthyroid state when compared to the euthyroid state. The preejection period index and the preejection period/left ventricular ejection time ratio were lower when the patients were hyperthyroid than when they were euthyroid. These data confirm the increased inotropic state and demonstrated increased diastolic relaxation velocities of the hyperthyroid left ventricle

Localização da lesão e achados do líquido cefalorraqueano na meningite tuberculosa: diferenças nos compartimentos lombar, cisternal e ventricular Location of the lesion and the cerebrospinal fluid findings in tuberculous meningitis: differences in the lumbar, cisternal and ventricular compartiments

Directory of Open Access Journals (Sweden)

Rafael R. Heringer

2005-06-01

Full Text Available A tuberculose permanece como uma das doenças infecciosas mais freqüentes no mundo. No presente estudo, relatamos um caso de meningite tuberculosa, que evoluiu com bloqueio do fluxo do líquido cefalorraqueano (LCR, causando dificuldade diagnóstica. Discute-se a importância da localização da lesão e sua influência no exame do LCR como apoio ao diagnóstico da meningite tuberculosa. No caso relatado, a pesquisa do bacilo álcool-ácido resistente foi positiva no LCR cisternal e negativa no LCR lombar e ventricular, demonstrando que a maior acurácia do teste esteve relacionada a maior proximidade da lesão inflamatória.Tuberculosis remains one of the most prevalent infectious diseases worldwide. In the present study, we describe a case of tuberculous meningitis that caused cerebrospinal fluid (CSF flow block, leading to difficulties in the diagnosis. The importance of the lesion site and its influence on CSF analysis as a support for the diagnosis of tuberculous meningitis is discussed. In this case, the search for acid-fast bacilii was positive in the cisternal CSF, but not in the ventricular and lumbar CSF, demonstrating the relationship between the accuracy of the test and the location of the inflamatory lesion disease.

Gas-cooled Fast Reactor (GFR) fuel and In-Core Fuel Management

International Nuclear Information System (INIS)

Weaver, K.D.; Sterbentz, J.; Meyer, M.; Lowden, R.; Hoffman, E.; Wei, T.Y.C.

2004-01-01

The Gas-Cooled Fast Reactor (GCFR) has been chosen as one of six candidates for development as a Generation IV nuclear reactor based on: its ability to fully utilize fuel resources; minimize or reduce its own (and other systems) actinide inventory; produce high efficiency electricity; and the possibility to utilize high temperature process heat. Current design approaches include a high temperature (2 850 C) helium cooled reactor using a direct Brayton cycle, and a moderate temperature (550 C - 650 C) helium or supercritical carbon dioxide (S-CO 2 ) cooled reactor using direct or indirect Brayton cycles. These design choices have thermal efficiencies that approach 45% to 50%, and have turbomachinery sizes that are much more compact compared to steam plants. However, there are challenges associated with the GCFR, which are the focus of current research. This includes safety system design for decay heat removal, development of high temperature/high fluence fuels and materials, and development of fuel cycle strategies. The work presented here focuses on the fuel and preliminary in-core fuel management, where advanced ceramic-ceramic (cercer) dispersion fuels are the main focus, and average burnups to 266 M Wd/kg appear achievable for the reference Si C/(U,TRU)C block/plate fuel. Solid solution (pellet) fuel in composite ceramic clad (Si C/Si C) is also being considered, but remains as a backup due to cladding fabrication challenges, and high centerline temperatures in the fuel. (Author)

A class-based search for the in-core fuel management optimization of a pressurized water reactor

International Nuclear Information System (INIS)

Alvarenga de Moura Meneses, Anderson; Rancoita, Paola; Schirru, Roberto; Gambardella, Luca Maria

2010-01-01

The In-Core Fuel Management Optimization (ICFMO) is a prominent problem in nuclear engineering, with high complexity and studied for more than 40 years. Besides manual optimization and knowledge-based methods, optimization metaheuristics such as Genetic Algorithms, Ant Colony Optimization and Particle Swarm Optimization have yielded outstanding results for the ICFMO. In the present article, the Class-Based Search (CBS) is presented for application to the ICFMO. It is a novel metaheuristic approach that performs the search based on the main nuclear characteristics of the fuel assemblies, such as reactivity. The CBS is then compared to the one of the state-of-art algorithms applied to the ICFMO, the Particle Swarm Optimization. Experiments were performed for the optimization of Angra 1 Nuclear Power Plant, located at the Southeast of Brazil. The CBS presented noticeable performance, providing Loading Patterns that yield a higher average of Effective Full Power Days in the simulation of Angra 1 NPP operation, according to our methodology.

A class-based search for the in-core fuel management optimization of a pressurized water reactor

Energy Technology Data Exchange (ETDEWEB)

Alvarenga de Moura Meneses, Anderson, E-mail: ameneses@lmp.ufrj.b [Federal University of Rio de Janeiro, COPPE, Nuclear Engineering Program, CP 68509, CEP 21.941-972, Rio de Janeiro, RJ (Brazil); Rancoita, Paola [IDSIA (Dalle Molle Institute for Artificial Intelligence), Galleria 2, 6982 Manno-Lugano, TI (Switzerland); Mathematics Department, Universita degli Studi di Milano (Italy); Schirru, Roberto [Federal University of Rio de Janeiro, COPPE, Nuclear Engineering Program, CP 68509, CEP 21.941-972, Rio de Janeiro, RJ (Brazil); Gambardella, Luca Maria [IDSIA (Dalle Molle Institute for Artificial Intelligence), Galleria 2, 6982 Manno-Lugano, TI (Switzerland)

2010-11-15

The In-Core Fuel Management Optimization (ICFMO) is a prominent problem in nuclear engineering, with high complexity and studied for more than 40 years. Besides manual optimization and knowledge-based methods, optimization metaheuristics such as Genetic Algorithms, Ant Colony Optimization and Particle Swarm Optimization have yielded outstanding results for the ICFMO. In the present article, the Class-Based Search (CBS) is presented for application to the ICFMO. It is a novel metaheuristic approach that performs the search based on the main nuclear characteristics of the fuel assemblies, such as reactivity. The CBS is then compared to the one of the state-of-art algorithms applied to the ICFMO, the Particle Swarm Optimization. Experiments were performed for the optimization of Angra 1 Nuclear Power Plant, located at the Southeast of Brazil. The CBS presented noticeable performance, providing Loading Patterns that yield a higher average of Effective Full Power Days in the simulation of Angra 1 NPP operation, according to our methodology.

Left Ventricular Geometry In Nigerians With Type II Diabetes Mellitus ...

African Journals Online (AJOL)

Background: Left ventricular hypertrophy is independently associated with increased incidence of cardiovascular disease, cardiovascular and all cause mortality. In a relatively healthy hypertensive adult population, type II diabetes is associated with higher left ventricular mass, concentric left ventricular geometry and lower ...

Assessment of right ventricular function using gated blood pool single photon emission computed tomography in inferior myocardial infarction with or without hemodynamically significant right ventricular infarction

International Nuclear Information System (INIS)

Takahashi, Masaharu

1992-01-01

Right ventricular function was assessed using gated blood pool single photon emission computed tomography (GSPECT) in 10 normal subjects and 14 patients with inferior myocardial infarction. Three-dimensional backbround subtraction was achieved by applying an optimal cut off level. The patient group consisted of 6 patients with definite hemodynamic abnormalities indicative of right ventricular infarction (RVI) and 8 other patients with significant obstructive lesion at the proximal portion of right coronary artery without obvious hemodynamic signs of RVI. Right ventricular regional wall motion abnormalities were demonstrated on GSPECT functional images and the indices of right ventricular function (i.e the right ventricular ejection fraction (RVEF), the right ventricular peak ejection rate (RVPER) and the right ventricular peak filling rate (RVPFR)) were significantly reduced in the patient group, not only in the patients with definite RVI but also in those without hemodynamic signs of RVI, even in the absence of definite hemodynamic signs, when the proximal portion of right coronary artery is obstructed. It is concluded that GSPECT is reliable for the assessment of right ventricular function and regional wall motion, and is also useful for the diagnosis of RVI. (author)

LEFT VENTRICULAR ROTATION, TWIST AND UNTWIST: PHYSIOLOGICAL ROLE AND CLINICAL RELEVANCE

Directory of Open Access Journals (Sweden)

E. N. Pavlyukova

2015-09-01

Full Text Available The helical ventricular myocardial band of Torrent-Guasp is a new concept, which provides strong grounds for reconciliation of some important aspects in cardiovascular medicine. Oblique fiber orientation provides left ventricular rotation, which in addition to radial thickening and longitudinal shortening, is predicted as an essential component of the effective left ventricular pumping. Left ventricular rotation can be measured in clinical practice noninvasively using echocardiography and this provides new opportunities for the assessment of different aspects of left ventricular mechanical function.

A case report of arrhythmogenic right ventricular dysplasia

Directory of Open Access Journals (Sweden)

Henry Anselmo Mayala

2013-01-01

Full Text Available Background Arrhythmogenic right ventricular dysplasia is an autosomal dominant disorder affecting parts of myocardium known as desmosomes, areas on the surface of heart muscle cells which link the cells together. The hallmark feature is fibro-fatty replacement of the right ventricle myocardium characterized by hypokinetic areas with associated arrhythmias originating in the right ventricle. CasePresentation Inthisreporta42yearoldmanwasadmittedatWuhanunion Hospital with the presenting complaints of visual hallucination and difficulty in breathing on exertion, with a family history of sudden death. Clinical and imaging findings are suggestive of Arrhythmogenic right ventricular dysplasia. Conclusion Despitebeingamongtherarecardiacdisease,Arrhythmogenicright ventricular dysplasia is an important cause of ventricular arrhythmias in children and young adults, it is also responsible for sudden cardiac death in the young population, making it necessary for this case report.

Diagnostic electrocardiographic dyad criteria of emphysema in left ventricular hypertrophy.

Science.gov (United States)

Lanjewar, Swapnil S; Chhabra, Lovely; Chaubey, Vinod K; Joshi, Saurabh; Kulkarni, Ganesh; Kothagundla, Chandrasekhar; Kaul, Sudesh; Spodick, David H

2013-01-01

The electrocardiographic diagnostic dyad of emphysema, namely a combination of the frontal vertical P-vector and a narrow QRS duration, can serve as a quasidiagnostic marker for emphysema, with specificity close to 100%. We postulated that the presence of left ventricular hypertrophy in emphysema may affect the sensitivity of this electrocardiographic criterion given that left ventricular hypertrophy generates prominent left ventricular forces and may increase the QRS duration. We reviewed the electrocardiograms and echocardiograms for 73 patients with emphysema. The patients were divided into two groups based on the presence or absence of echocardiographic evidence of left ventricular hypertrophy. The P-vector, QRS duration, and forced expiratory volume in one second (FEV1) were computed and compared between the two subgroups. There was no statistically significant difference in qualitative lung function (FEV1) between the subgroups. There was no statistically significant difference in mean P-vector between the subgroups. The mean QRS duration was significantly longer in patients with left ventricular hypertrophy as compared with those without left ventricular hypertrophy. The presence of left ventricular hypertrophy may not affect the sensitivity of the P-vector verticalization when used as a lone criterion for diagnosing emphysema. However, the presence of left ventricular hypertrophy may significantly reduce the sensitivity of the electrocardiographic diagnostic dyad in emphysema, as it causes a widening of the QRS duration.

Evaluation of the accuracy of ventricular volume measurement by ultrafast CT

International Nuclear Information System (INIS)

Cui Wei; Dai Ruping; Guo Yuyin

1997-01-01

The authors evaluated the accuracy of ventricular volume measured by ultrafast CT (UFCT); and (2) compared the value of ventricular volume derived from long- and short-axis view. Fourteen human left ventricular casts and 15 right ventricular casts were scanned by Imatron C-150 scanner along both the long- and short-axis. The scan protocol was similar to that used in vivo. Eight 7 mm-thick slices were obtained from each cast for both long- and short-axis views. Ventricular volume was determined by the modified Simpson's rule provided by Inamtron Inc. The actual volumes of the ventricular casts were determined by the amount of water displacement by the cast. The actual volumes for left and right ventricles were 55.57 +- 28.91 ml and 64.23 +- 24.51 ml, respectively, the left and right ventricular volumes determined by UFCT were 66.50 +- 33.04 ml and 76.47 +-28.70 ml from long-axis view, and 60.36 +- 29.90 ml and 75.36 +- 28.73 ml from short-axis view, respectively. The measurements by UFCT were significantly greater than the actual volumes of the casts, both for the left and right ventricles (P 0.990). Both left and right ventricular volumes can be determined by UFCT with identical accuracy for both long- and short-axis views in calculating ventricular volume; however, overestimation of ventricular volume by UFCT should be noted

Influence of left ventricular hypertrophy on infarct size and left ventricular ejection fraction in ST-elevation myocardial infarction

International Nuclear Information System (INIS)

Małek, Łukasz A.; Śpiewak, Mateusz; Kłopotowski, Mariusz; Petryka, Joanna; Mazurkiewicz, Łukasz; Kruk, Mariusz; Kępka, Cezary; Miśko, Jolanta; Rużyłło, Witold; Witkowski, Adam

2012-01-01

Background: Left ventricular hypertrophy (LVH) predisposes to larger infarct size, which may be underestimated by the left ventricular ejection fraction (LVEF) due to supranormal systolic performance often present in patients with LVH. The aim of the study was to compare infarct size and LVEF in patients with ST-segment elevation myocardial infarction (STEMI) and increased left ventricular mass on cardiac magnetic resonance (CMR). Methods: The study included unselected group of 52 patients (61 ± 11 years, 69% male) with first STEMI who had CMR after median 5 days from the onset of the event. Left ventricular hypertrophy (LVH) was defined as left ventricular mass index exceeding 95th percentile of references values for age and gender. Infarct size was assessed with means of late gadolinium enhancement (LGE). Results: LVH was found in 16 patients (31%). In comparison to the rest of the group, patients with LVH had higher absolute and relative infarct mass (p = 0.002 and p = 0.02, respectively). LVH was related to higher prevalence of microvascular obstruction and myocardial haemorrhage and higher number of LV segments with transmural necrosis (p = 0.02, p = 0.01 and p = 0.01, respectively). Despite marked difference in the infarct size between both studied subgroups there was no difference in LVEF and mean number of dysfunctional LV segments. Conclusions: Patients with LVH undergoing STEMI have larger infarct size underestimated by the LV systolic performance in comparison to patients without LVH.

Ventricular kinetic energy may provide a novel noninvasive way to assess ventricular performance in patients with repaired tetralogy of Fallot.

Science.gov (United States)

Jeong, Daniel; Anagnostopoulos, Petros V; Roldan-Alzate, Alejandro; Srinivasan, Shardha; Schiebler, Mark L; Wieben, Oliver; François, Christopher J

2015-05-01

Ventricular kinetic energy measurements may provide a novel imaging biomarker of declining ventricular efficiency in patients with repaired tetralogy of Fallot. Our purpose was to assess differences in ventricular kinetic energy with 4-dimensional flow magnetic resonance imaging between patients with repaired tetralogy of Fallot and healthy volunteers. Cardiac magnetic resonance, including 4-dimensional flow magnetic resonance imaging, was performed at rest in 10 subjects with repaired tetralogy of Fallot and 9 healthy volunteers using clinical 1.5T and 3T magnetic resonance imaging scanners. Right and left ventricular kinetic energy (KERV and KELV), main pulmonary artery flow (QMPA), and aortic flow (QAO) were quantified using 4-dimensional flow magnetic resonance imaging data. Right and left ventricular size and function were measured using standard cardiac magnetic resonance techniques. Differences in peak systolic KERV and KELV in addition to the QMPA/KERV and QAO/KELV ratios between groups were assessed. Kinetic energy indices were compared with conventional cardiac magnetic resonance parameters. Peak systolic KERV and KELV were higher in patients with repaired tetralogy of Fallot (6.06 ± 2.27 mJ and 3.55 ± 2.12 mJ, respectively) than in healthy volunteers (5.47 ± 2.52 mJ and 2.48 ± 0.75 mJ, respectively), but were not statistically significant (P = .65 and P = .47, respectively). The QMPA/KERV and QAO/KELV ratios were lower in patients with repaired tetralogy of Fallot (7.53 ± 5.37 mL/[cycle mJ] and 9.65 ± 6.61 mL/[cycle mJ], respectively) than in healthy volunteers (19.33 ± 18.52 mL/[cycle mJ] and 35.98 ± 7.66 mL/[cycle mJ], respectively; P tetralogy of Fallot. Quantification of ventricular kinetic energy in patients with repaired tetralogy of Fallot is a new observation. Future studies are needed to determine whether changes in ventricular kinetic energy can provide earlier evidence of ventricular dysfunction and guide future medical and

Right ventricular function: methodologic and clinical considerations in noninvasive scintigraphic assessment

International Nuclear Information System (INIS)

Manno, B.V.; Iskandrian, A.S.; Hakki, A.H.

1984-01-01

Right ventricular function plays an important role in many cardiac disorders. Changes in left ventricular function, right ventricular afterload and preload, cardiac medications and ischemia may affect right ventricular function. Radionuclide ventriculography permits quantitative assessment of regional and global function of the right ventricle. This assessment can be made at rest, during exercise or after pharmacologic interventions. The overlap between right ventricle and right atrium is a major limitation for gated scintigraphic techniques. The use of imaging with newer short-lived radionuclides may permit more accurate and reproducible assessment of right ventricular function by means of the first pass method. Further work in areas related to improvement of techniques and the impact of right ventricular function on prognosis is needed

A unified methodology for single- and multiobjective in-core fuel management optimisation based on augmented Chebyshev scalarisation and a harmony search algorithm

International Nuclear Information System (INIS)

Schlünz, E.B.; Bokov, P.M.; Prinsloo, R.H.; Vuuren, J.H. van

2016-01-01

Highlights: • Unified methodology for in-core fuel management optimisation (ICFMO). • Addresses single- and multiobjective constrained and unconstrained ICFMO problems. • Augmented Chebyshev scalarising objective function with additive penalty function. • Harmony search algorithm yields high-quality solution or approximate Pareto set. • Methodology provides cycle-to-cycle optimisation decision support capabilities. - Abstract: The in-core fuel management optimisation (ICFMO) problem is the problem of finding an optimal fuel reload configuration for a nuclear reactor core. ICFMO may involve the pursuit of a single or multiple objectives, while satisfying several constraints. Very little multiobjective ICFMO research involving the fundamental notion of Pareto optimality has, however, been performed. In this paper, a unified methodology is proposed for the modelling and solution of single- and multiobjective ICFMO problems, be they constrained or unconstrained. With this methodology, ICFMO problems incorporating a variety of objectives and/or constraints may be modelled and solved rapidly, thus providing a cycle-to-cycle optimisation decision support capability for nuclear reactors. An augmented Chebyshev scalarising objective function is incorporated in the methodology for modelling any number of objectives, while an additive penalty function handles potential constraints. Furthermore, an adapted harmony search algorithm is used to solve a given ICFMO problem. The algorithm is able to yield a single solution or a nondominated set of solutions as result (depending on the number of objectives in a problem). The applicability of the methodology is demonstrated by solving (approximately) a variety of ICFMO test problems for the SAFARI-1 nuclear research reactor. The results indicate that the methodology may be used as an effective decision support tool for reactor operators tasked with designing reload configurations from cycle to cycle.

Race differences in ventricular remodeling and function among college football players.

Science.gov (United States)

Haddad, Francois; Peter, Shanon; Hulme, Olivia; Liang, David; Schnittger, Ingela; Puryear, Josephine; Gomari, Fatemeh A; Finocchiaro, Gherardo; Myers, Jonathan; Froelicher, Victor; Garza, Daniel; Ashley, Euan A

2013-07-01

Athletic training is associated with increases in ventricular mass and volume. Recent studies have shown that left ventricular mass increases proportionally in white athletes with a mass/volume ratio approaching unity. The objective of this study was to compare the proportionality in ventricular remodeling and ventricular function in black versus white National Collegiate Athletic Association Division I football players. From 2008 to 2011, football players at Stanford University underwent cardiovascular screening with a 12-point history and physical examination, electrocardiography, and focused echocardiography. Compared with white players, black players had on average higher left ventricular mass indexes (77 ± 11 vs 71 ± 11 g/m(2), p = 0.009), higher mass/volume ratios (1.18 ± 0.16 vs 1.06 ± 0.09 g/ml, p 1.2. Mass/volume ratio was inversely related to early diastolic tissue Doppler velocity e' (r = -0.50, p football players exhibit more concentric ventricular remodeling, lower early diastolic annular velocities, and increased ventricular voltage compared with white players. Ventricular mass increases proportionally to volume in white players but not in black players. Copyright © 2013 Elsevier Inc. All rights reserved.

Annular subvalvular left ventricular aneurysm in Bahia, Brazil.

Science.gov (United States)

Guimarães, A C; Filho, A S; Esteves, J P; Abreu, W N; Vinhaes, L A; de Almeida Souza, J A; Machado, A

1976-10-01

Two cases of left ventricular aneurysm, a 16-year-old black boy and a 23-year-old white girl, from Bahia, Brazil, are presented. In both patients there was enlargement of the cardiac silhouette and a prominent bulge of the left inferior border. On the right oblique view a ring of calcium at the ventricular opening of the aneurysms was visualized. A left ventriculogram showed a huge aneurysm in the first case and a bulge on the lateral wall of the left ventricle in the other. Cardiac catheterization showed a rise in left and right ventricular end-diastolic pressures and in the mean pulmonary artery pressure. In the first case the contour of the right ventricular pressure curve showed a restrictive pattern. The similarities of these aneurysms with the annular submitral type described in young black Africans are stressed.

Central-Approach Surgical Repair of Coarctation of the Aorta with a Back-up Left Ventricular Assist Device for an Infant Presenting with Severe Left Ventricular Dysfunction

Directory of Open Access Journals (Sweden)

Tae Hoon Kim

2015-12-01

Full Text Available A two-month-old infant presented with coarctation of the aorta, severe left ventricular dysfunction, and moderate to severe mitral regurgitation. Through median sternotomy, the aortic arch was repaired under cardiopulmonary bypass and regional cerebral perfusion. The patient was postoperatively supported with a left ventricular assist device for five days. Left ventricular function gradually improved, eventually recovering with the concomitant regression of mitral regurgitation. Prompt surgical repair of coarctation of the aorta is indicated for patients with severe left ventricular dysfunction. A central approach for surgical repair with a back-up left ventricular assist device is a safe and effective treatment strategy for these patients.

Central-Approach Surgical Repair of Coarctation of the Aorta with a Back-up Left Ventricular Assist Device for an Infant Presenting with Severe Left Ventricular Dysfunction.

Science.gov (United States)

Kim, Tae Hoon; Shin, Yu Rim; Kim, Young Sam; Kim, Do Jung; Kim, Hyohyun; Shin, Hong Ju; Htut, Aung Thein; Park, Han Ki

2015-12-01

A two-month-old infant presented with coarctation of the aorta, severe left ventricular dysfunction, and moderate to severe mitral regurgitation. Through median sternotomy, the aortic arch was repaired under cardiopulmonary bypass and regional cerebral perfusion. The patient was postoperatively supported with a left ventricular assist device for five days. Left ventricular function gradually improved, eventually recovering with the concomitant regression of mitral regurgitation. Prompt surgical repair of coarctation of the aorta is indicated for patients with severe left ventricular dysfunction. A central approach for surgical repair with a back-up left ventricular assist device is a safe and effective treatment strategy for these patients.

Advanced quantitative echocardiography in arrhythmogenic right ventricular cardiomyopathy

DEFF Research Database (Denmark)

Kjaergaard, Jesper; Hastrup Svendsen, Jesper; Sogaard, Peter

2007-01-01

BACKGROUND: Arrhythmogenic right ventricular (RV) cardiomyopathy (ARVC) is a regional disease of the RV myocardium with variable degrees of left ventricular involvement. Three-dimensional echocardiography and Doppler tissue imaging (DTI) are new echocardiographic modalities for the evaluation......, patients with ARVC had a decreased RV ejection fraction (0.47 +/- 0.08 vs 0.53 +/- 0.05, P vs 15.1 +/- 3.7 cm/s, P left ventricle (7.0 +/- 2.6 vs 9.5 +/- 1.9 cm/s, P ... of the longitudinal motility appears to be a sensitive marker of preclinical left ventricular involvement....

Reversibility of ventricular dysfunction: clinical experience in a medical office

Directory of Open Access Journals (Sweden)

Antonio Carlos Pereira Barretto

2001-12-01

Full Text Available OBJECTIVE - To describe clinical observations of marked improvement in ventricular dysfunction in a medical office environment under circumstances differing from those in study protocols and multicenter studies performed in hospital or with outpatient cohorts. METHODS - Eleven cardiac failure patients with marked ventricular dysfunction receiving treatment at a doctors office between 1994 and 1999 were studied. Their ages ranged from 20 and 66 years (mean 39.42±14.05 years; 7 patients were men, 4 were women. Cardiopathic etiologies were arterial hypertension in 5 patients, peripartum cardiomyopathy in 2, nondefined myocarditis in 2, and alcoholic cardiomyopathy in 4. Initial echocardiograms revealed left ventricular dilatation (average diastolic diameter, 69.45±8.15mm, reduced left ventricular ejection fraction (0.38±0.08 and left atrial dilatation (43.36±5.16mm. The therapeutic approach followed consisted of patient orientation, elimination of etiological or causal factors of cardiac failure, and prescription of digitalis, diuretics, and angiotensinconverting enzyme inhibitors. RESULTS - Following treatment, left ventricular ejection fraction changed to 0.63±0.09; left ventricular diameters changed to 57.18±8.13mm, and left atrium diameters changed to 37.27±8.05mm. Maximum improvement was noted after 16.9±8.63 (6 to 36 months. CONCLUSION - Patients with serious cardiac failure and ventricular dysfunction caused by hypertension, alcoholism, or myocarditis can experience marked improvement in ventricular dysfunction after undergoing appropriate therapy within the venue of the doctor's office.

Fatigue as Presenting Symptom and a High Burden of Premature Ventricular Contractions Are Independently Associated With Increased Ventricular Wall Stress in Patients With Normal Left Ventricular Function.

Science.gov (United States)

van Huls van Taxis, Carine F B; Piers, Sebastiaan R D; de Riva Silva, Marta; Dekkers, Olaf M; Pijnappels, Daniël A; Schalij, Martin J; Wijnmaalen, Adrianus P; Zeppenfeld, Katja

2015-12-01

High idiopathic premature ventricular contractions (PVC) burden has been associated with PVC-induced cardiomyopathy. Patients may be symptomatic before left ventricular (LV) dysfunction develops. N-terminal pro-B-type natriuretic peptide (NT-proBNP) and circumferential end-systolic wall stress (cESS) on echocardiography are markers for increased ventricular wall stress. This study aimed to evaluate the relation between presenting symptoms, PVC burden, and increased ventricular wall stress in patients with frequent PVCs and preserved LV function. Eighty-three patients (41 men; 49±15 years) with idiopathic PVCs and normal LV function referred for PVC ablation were included. Type of symptoms (palpitations, fatigue, and [near-]syncope), PVC burden on 24-hour Holter, NT-proBNP levels, and cESS on echocardiography were assessed before and 3 months after ablation. Sustained successful ablation was defined as ≥80% PVC burden reduction during follow-up. Patients were symptomatic for 24 months (Q1-Q3, 16-60); 73% reported palpitations, 47% fatigue, and 30% (near-)syncope. Baseline PVC burden was 23±13%, median NT-proBNP 92 pg/mL (Q1-Q3 50-156), and cESS 143±35 kdyne/cm(2). Fatigue was associated with higher baseline NT-proBNP and cESS (PFatigue was independently associated with a significantly larger reduction in NT-proBNP. In patients with nonsuccessful ablation, NT-proBNP and cESS remained unchanged. In patients with frequent PVCs and preserved LV function, fatigue was associated with higher baseline NT-proBNP and cESS, and with a significantly larger reduction in NT-proBNP after sustained successful ablation. These findings support a link between fatigue and PVC-induced increased ventricular wall stress, despite preserved LV function. © 2015 American Heart Association, Inc.

Clinical use of ultrashort-lived radionuclide krypton-81m for noninvasive analysis of right ventricular performance in normal subjects and patients with right ventricular dysfunction

International Nuclear Information System (INIS)

Nienaber, C.A.; Spielmann, R.P.; Wasmus, G.; Mathey, D.G.; Montz, R.; Bleifeld, W.H.

1985-01-01

The ultrashort-lived radionuclide krypton-81m, eluted in 5% dextrose from a bedside rubidium-81m generator, was intravenously infused for rapid imaging of the right-sided heart chambers in the right anterior oblique projection adjusted for optimal right atrioventricular separation. Left-sided heart and lung background was minimized by rapid decay and efficient exhalation of krypton-81m, requiring no algorithm for background correction. A double region of interest method decreased the variability in the assessment of ejection fraction to 5%. In 10 normal subjects, 11 patients with pulmonary hypertension, 4 patients with right ventricular outflow tract obstruction and 4 patients with right ventricular infarction, right ventricular ejection fraction determined by krypton-81m equilibrium blood pool imaging ranged from 14 to 76%. The correlation between these values and those determined by cineangiography according to Simpson's rule was close: r . 0.93 for all data points, r . 0.92 for studies at rest and r . 0.93 for exercise studies. Exercise-related changes in right ventricular function revealed a disturbed functional reserve with pulmonary hypertension and right ventricular infarction, whereas in compensated right ventricular outflow tract obstruction there was a physiologic increase in ejection fraction with exercise. Thus, equilibrium-gated right ventricular imaging using ultrashort-lived krypton-81m is a simple, accurate and reproducible method with potential for serial assessment of right ventricular ejection fraction in a variety of right ventricular anatomic and functional abnormalities, both at rest and during exercise. Advantages of this method include an extremely low radiation dose to patients and clear right atrioventricular separation without the need to correct for background activity

Videodensitometric assessment of right and left ventricular functions by digital subtraction angiography

International Nuclear Information System (INIS)

Ikeda, Hisao; Yoshiga, Osamu; Shibao, Keigo

1987-01-01

Intravenous digital subtraction (DS) ventriculography was performed in a series of 50 patients with heart diseases to determine right and left ventricular volumes and systolic indices. Right ventricular volume and right ventricular ejection fraction obtained by DS ventriculography were well correlated with those by geometric methods. In 43 patients with left ventricular ejection fraction of 55 % or greater, end-diastolic volume, stroke volume, and ejection fraction in the right ventricle did not differ from those in the left ventricle ; however, both the 1/3 ejection fraction and the peak ejection rate of the right ventricle were significantly lower than those of the left ventricle, suggesting the different modes of left and right ventricular contraction. In the other seven patients with chronic left ventricular failure, right ventricular systolic function may be preserved, even when left ventricular function is severely impaired. Digital subtraction ventriculography has proved to be a simple, useful method in the quanlitative and quantitative assessments of the right and left ventricles. (Namekawa, K.)

Electrical Signs predictors of malignant ventricular arrhythmias

International Nuclear Information System (INIS)

Aleman Fernandez, Ailema Amelia; Dorantes Sanchez, Margarita

2012-01-01

Recurrence of malignant ventricular arrhythmia is frequent in cardioverter-defibrillators related patients. The risk stratification is difficult, there are numerous electrocardiographic predictors but his sensibility and specificity are not absolute. The limit between normal and pathological is not defined, besides the complexity of ventricular arrhythmias. We expose different electrocardiographic predictors that can help to better individual risk stratification

Nonischemic Left Ventricular Scar as a Substrate of Life-Threatening Ventricular Arrhythmias and Sudden Cardiac Death in Competitive Athletes.

Science.gov (United States)

Zorzi, Alessandro; Perazzolo Marra, Martina; Rigato, Ilaria; De Lazzari, Manuel; Susana, Angela; Niero, Alice; Pilichou, Kalliopi; Migliore, Federico; Rizzo, Stefania; Giorgi, Benedetta; De Conti, Giorgio; Sarto, Patrizio; Serratosa, Luis; Patrizi, Giampiero; De Maria, Elia; Pelliccia, Antonio; Basso, Cristina; Schiavon, Maurizio; Bauce, Barbara; Iliceto, Sabino; Thiene, Gaetano; Corrado, Domenico

2016-07-01

The clinical profile and arrhythmic outcome of competitive athletes with isolated nonischemic left ventricular (LV) scar as evidenced by contrast-enhanced cardiac magnetic resonance remain to be elucidated. We compared 35 athletes (80% men, age: 14-48 years) with ventricular arrhythmias and isolated LV subepicardial/midmyocardial late gadolinium enhancement (LGE) on contrast-enhanced cardiac magnetic resonance (group A) with 38 athletes with ventricular arrhythmias and no LGE (group B) and 40 healthy control athletes (group C). A stria LGE pattern with subepicardial/midmyocardial distribution, mostly involving the lateral LV wall, was found in 27 (77%) of group A versus 0 controls (group C; P<0.001), whereas a spotty pattern of LGE localized at the junction of the right ventricle to the septum was respectively observed in 11 (31%) versus 10 (25%; P=0.52). All athletes with stria pattern showed ventricular arrhythmias with a predominant right bundle branch block morphology, 13 of 27 (48%) showed ECG repolarization abnormalities, and 5 of 27 (19%) showed echocardiographic hypokinesis of the lateral LV wall. The majority of athletes with no or spotty LGE pattern had ventricular arrhythmias with a predominant left bundle branch block morphology and no ECG or echocardiographic abnormalities. During a follow-up of 38±25 months, 6 of 27 (22%) athletes with stria pattern experienced malignant arrhythmic events such as appropriate implantable cardiac defibrillator shock (n=4), sustained ventricular tachycardia (n=1), or sudden death (n=1), compared with none of athletes with no or LGE spotty pattern and controls. Isolated nonischemic LV LGE with a stria pattern may be associated with life-threatening arrhythmias and sudden death in the athlete. Because of its subepicardial/midmyocardial location, LV scar is often not detected by echocardiography. © 2016 The Authors.

Adjustable, physiological ventricular restraint improves left ventricular mechanics and reduces dilatation in an ovine model of chronic heart failure.

Science.gov (United States)

Ghanta, Ravi K; Rangaraj, Aravind; Umakanthan, Ramanan; Lee, Lawrence; Laurence, Rita G; Fox, John A; Bolman, R Morton; Cohn, Lawrence H; Chen, Frederick Y

2007-03-13

Ventricular restraint is a nontransplantation surgical treatment for heart failure. The effect of varying restraint level on left ventricular (LV) mechanics and remodeling is not known. We hypothesized that restraint level may affect therapy efficacy. We studied the immediate effect of varying restraint levels in an ovine heart failure model. We then studied the long-term effect of restraint applied over a 2-month period. Restraint level was quantified by use of fluid-filled epicardial balloons placed around the ventricles and measurement of balloon luminal pressure at end diastole. At 4 different restraint levels (0, 3, 5, and 8 mm Hg), transmural myocardial pressure (P(tm)) and indices of myocardial oxygen consumption (MVO2) were determined in control (n=5) and ovine heart failure (n=5). Ventricular restraint therapy decreased P(tm) and MVO2, and improved mechanical efficiency. An optimal physiological restraint level of 3 mm Hg was identified to maximize improvement without an adverse affect on systemic hemodynamics. At this optimal level, end-diastolic P(tm) and MVO2 indices decreased by 27% and 20%, respectively. The serial longitudinal effects of optimized ventricular restraint were then evaluated in ovine heart failure with (n=3) and without (n=3) restraint over 2 months. Optimized ventricular restraint prevented and reversed pathological LV dilatation (130+/-22 mL to 91+/-18 mL) and improved LV ejection fraction (27+/-3% to 43+/-5%). Measured restraint level decreased over time as the LV became smaller, and reverse remodeling slowed. Ventricular restraint level affects the degree of decrease in P(tm), the degree of decrease in MVO2, and the rate of LV reverse remodeling. Periodic physiological adjustments of restraint level may be required for optimal restraint therapy efficacy.

Radionuclide evaluation of left ventricular function with nonimaging probes.

Science.gov (United States)

Wexler, J P; Blaufox, M D

1979-10-01

Portable nonimaging probes have been developed that can evaluate left ventricular function using radionuclide techniques. Two modes of data acquisition are possible with these probe systems, first-pass and gated. Precordial radiocardiograms obtained after a bolus injection can be used to determine cardiac output, pulmonary transit time, pulmonary blood volume, left ventricle ejection fraction, and left-to-right shunts. Gated techniques can be used to determine left ventricular ejection fraction and sytolic time intervals. Probe-determined indices of left ventricular function agree excellently with comparable measurements determined by conventional camera-computer methods as well as by invasive techniques. These have begun to be used in a preliminary manner in a variety of clinical problems associated with left ventricular dysfunction. This review discusses the types of probe systems available, the methods used in positioning them, and details the specifics of their data acquisition and processing capacity. The major criticisms of probe methods are that they are nonimaging and that they measure global rather than regional left ventricular function. In spite of these criticisms, probe systems, because of their portability, high sensitivity, and relatively low cost are useful supplements to conventional camera-computer systems for the measurement of parameters of left ventricular performance using radionuclide techniques.

Ventricular Arrhythmic Storm after Initiating Sacubitril/Valsartan.

Science.gov (United States)

Vicent, Lourdes; Juárez, Miriam; Martín, Irene; García, Jorge; González-Saldívar, Hugo; Bruña, Vanesa; Devesa, Carolina; Sousa-Casasnovas, Iago; Fernández-Avilés, Francisco; Martínez-Sellés, Manuel

Sacubitril/valsartan was approved recently for the treatment of patients with heart failure and reduced ejection fraction. We present 6 cases of ventricular arrhythmia, that occurred shortly after sacubitril/valsartan initiation, that required drug withdrawal. Other potential triggering factors of electrical storm were ruled out and, from the arrhythmic perspective, all of the patients were stable in the previous year. Our aim is to describe the possible association of sacubitril/valsartan with arrhythmic storm. This was an observational monocentric study performed in the first 7 months of sacubitril/valsartan commercialization in Spain (October 2016). All patients were included in the SUMA (Sacubitril/Varsartan Usado Ambulatoriamente en Madrid [Sacubitril/Valsartan Used in Outpatients in Madrid]) registry. Patients were consecutively enrolled on the day they started the drug. Ventricular arrhythmic storm was defined as ≥2 episodes of sustained ventricular arrhythmia or defibrillator therapy application in 24 h. From 108 patients who received the drug, 6 presented with ventricular arrhythmic storm (5.6%). Baseline characteristics were similar in the patients with and without ventricular arrhythmic storm. The total number of days that sacubitril/valsartan was administered to each patient was 5, 6, 44 (8 since titration), 84, 93, and 136 (105 since titration), respectively. Our data are not enough to infer a cause-and-effect relationship. Further investigations regarding a potential proarrhythmic effect of sacubitril/valsartan are probably needed. © 2018 S. Karger AG, Basel.

Assessment of inter-atrial, inter-ventricular, and atrio-ventricular interactions in tetralogy of Fallot patients after surgical correction. Insights from two-dimensional speckle tracking and three-dimensional echocardiography.

Science.gov (United States)

Abd El Rahman, Mohamed; Raedle-Hurst, Tanja; Rentzsch, Axel; Schäfers, Hans-Joachim; Abdul-Khaliq, Hashim

2015-10-01

We aimed to assess biatrial size and function, interactions on atrial and ventricular levels, and atrio-ventricular coupling in patients after tetralogy of Fallot repair. A total of 34 patients with a mean age of 20.9±9 years, and 35 healthy controls, underwent two-dimensional speckle tracking echocardiography for ventricular and atrial strain measurements and real-time three-dimensional echocardiography to assess ventricular and atrial volumes. When compared with controls, tetralogy of Fallot patients had significantly reduced right atrial peak atrial longitudinal strain (ptetralogy of Fallot group, left ventricular ejection fraction was negatively related to the right ventricular end-systolic volume normalised to body surface area (r=-0.62, ptetralogy of Fallot patients, biatrial dysfunction exists and can be quantified via two-dimensional speckle tracking echocardiography as well as real-time three-dimensional echocardiography. Different forms of interactions on atrial and ventricular levels are evident among such cohorts.

Diagnostic electrocardiographic dyad criteria of emphysema in left ventricular hypertrophy

Directory of Open Access Journals (Sweden)

Lanjewar SS

2013-11-01

Full Text Available Swapnil S Lanjewar,1 Lovely Chhabra,1 Vinod K Chaubey,1 Saurabh Joshi,1 Ganesh Kulkarni,1 Chandrasekhar Kothagundla,1 Sudesh Kaul,1 David H Spodick21Department of Internal Medicine, 2Department of Cardiovascular Medicine, Saint Vincent Hospital, University of Massachusetts Medical School, Worcester, MA, USABackground: The electrocardiographic diagnostic dyad of emphysema, namely a combination of the frontal vertical P-vector and a narrow QRS duration, can serve as a quasidiagnostic marker for emphysema, with specificity close to 100%. We postulated that the presence of left ventricular hypertrophy in emphysema may affect the sensitivity of this electrocardiographic criterion given that left ventricular hypertrophy generates prominent left ventricular forces and may increase the QRS duration.Methods: We reviewed the electrocardiograms and echocardiograms for 73 patients with emphysema. The patients were divided into two groups based on the presence or absence of echocardiographic evidence of left ventricular hypertrophy. The P-vector, QRS duration, and forced expiratory volume in one second (FEV1 were computed and compared between the two subgroups.Results: There was no statistically significant difference in qualitative lung function (FEV1 between the subgroups. There was no statistically significant difference in mean P-vector between the subgroups. The mean QRS duration was significantly longer in patients with left ventricular hypertrophy as compared with those without left ventricular hypertrophy.Conclusion: The presence of left ventricular hypertrophy may not affect the sensitivity of the P-vector verticalization when used as a lone criterion for diagnosing emphysema. However, the presence of left ventricular hypertrophy may significantly reduce the sensitivity of the electrocardiographic diagnostic dyad in emphysema, as it causes a widening of the QRS duration.Keywords: emphysema, electrocardiogram, left ventricular hypertrophy, chronic

A case report of arrhythmogenic right ventricular dysplasia

Directory of Open Access Journals (Sweden)

Henry Anselmo Mayala

2013-07-01

Full Text Available Background Arrhythmogenic right ventricular dysplasia is an autosomal dominant disorder affecting parts of myocardium known as desmosomes, areas on the surface of heart muscle cells which link the cells together. The hallmark feature is fibro-fatty replacement of the right ventricle myocardium characterized by hypokinetic areas with associated arrhythmias originating in the right ventricle. Case Presentation In this report a 42 year old man was admitted at Wuhan union Hospital with the presenting complaints of visual hallucination and difficulty in breathing on exertion, with a family history of sudden death. Clinical and imaging findings are suggestive of Arrhythmogenic right ventricular dysplasia. Conclusion Despite being among the rare cardiac disease, Arrhythmogenic right ventricular dysplasia is an important cause of ventricular arrhythmias in children and young adults, it is also responsible for sudden cardiac death in the young population, making it necessary for this case report.

[Idiopathic ventricular arrhythmia in children. Apropos of 24 cases].

Science.gov (United States)

Coeurderoy, A; Almange, C; Laurent, M; Biron, Y; Leborgne, P

1985-12-01

The severity and prognosis of idiopathic ventricular arrhythmias in childhood were studied in 24 patients (12 boys, 12 girls) with an average age of 8 years at the time of diagnosis of the arrhythmia. Investigations included clinical assessment and analysis of basal ECG (morphology of the arrhythmias) and dynamic recordings (Holter and exercise stress testing). The clinical course was followed for an average of 3.8 years. The patients were classified in two groups: monomorphic arrhythmias (Group I) and polymorphic arrhythmias (Group II). Group I was divided into 4 subgroups: isolated ventricular extrasystoles (IA), 11 patients; ventricular extrasystoles with bursts of ventricular tachycardia (IB), 6 patients; sustained ventricular tachycardia without intercritical extrasystoles (IC), 1 patient; accelerated idioventricular rhythm (ID), 2 patients. Subgroups IA, IB and ID were characterised by the absence of symptoms, the disappearance of the arrhythmia on exercise, the decreased efficacy of antiarrhythmic drugs and an excellent prognosis. Therapeutic abstention was the rule in these patients. Patients in Group IC were characterised by the variability of their symptoms, the absence of exercise induced arrhythmias, the need for treatment in most cases and a good long-term prognosis. Group II was divided into 2 subgroups: adrenergic polymorphic ventricular tachycardia (IIA), 2 patients, and non-adrenergic polymorphic ventricular tachycardia (IIB), 2 patients. Patients in Subgroup IIA were characterised by syncope on exercise or emotion, the need for betablocker therapy which considerably improved the patients symptoms but which did not usually prevent sudden death.(ABSTRACT TRUNCATED AT 250 WORDS)

Ventricular and myocardial scintiscanning: Methodical fundamentals

International Nuclear Information System (INIS)

Standke, R.; Hoer, G.; Maul, F.D.

1984-01-01

Nuclear cardiology is concerned with non invasive procedures to quantitate global and regional left ventricular function (Radionuclide ventriculography), also the imaging of vitally perfused myocardium (Myocardial scintigraphy) is achieved. A gammacamera and a minicomputer are necessary. Radionuclide ventriculography enables the analysis of global and regional time dependent left ventricular volume curves and hence the evaluation of contraction and contractility of the heart muscle. The basis is a sequence of scans covering an average heartcycle. This sequence may be produced either by first pass or equilibrium technique. Myocardial scintigraphy at rest images vital myocardium, scans immediately after exercise represent the interference of myocardial perfusion and muscle mass. The regional difference (Redistribution) between normalized exercise- and rest scans provide quantitative parameters to detect impairment of exercise-induced myocardial perfusion anomalies. The procedures of sectorial analysis of left ventricular function and myocardial perfusion are presented. (orig.) [de

Left ventricular dysfunction after closure of large patent ductus arteriosus.

Science.gov (United States)

Galal, M Omar; Amin, Mohamed; Hussein, Arif; Kouatli, Amjad; Al-Ata, Jameel; Jamjoom, Ahmed

2005-03-01

Changes in left ventricular dimensions and performance were studied in 43 patients after transcatheter occlusion or surgical ligation of patent ductus arteriosus. The patients were assigned to 2 groups based on their ductal diameter: >/= 3.1 mm to group A (n = 27) and ventricular end-diastolic diameter than group B, while all patients had normal shortening fraction and ejection fraction. Within 1 month after intervention, left ventricular end-diastolic diameter showed a trend towards regression while shortening fraction and ejection fraction decreased significantly in group A. There were no significant changes in these parameters in group B. Between 1 and 6 months after intervention, left ventricular performance improved in most of the group A patients who were followed up. We conclude that closure of large ductus arteriosus in children leads to significant immediate deterioration of left ventricular performance, which appears to recover within a few months. Echocardiographic study before hospital discharge is recommended in these patients. Serious deterioration of ventricular performance after closure may warrant the use of angiotensin converting enzyme inhibitors.

A case of appropriate inappropriate device therapy: Hyperkalemia-induced ventricular oversensing

Science.gov (United States)

Oudit, Gavin Y; Cameron, Doug; Harris, Louise

2008-01-01

The present case describes a patient who received inappropriate, but potentially life-saving, therapy from her implantable cardioverter defibrillator (ICD) in the setting of acute hyperkalemia (plasma potassium concentration = 8 mM). Hyperkalemia was associated with the development of a slow sinusoidal ventricular tachycardia, at a rate of 100 beats/min to 125 beats/min (610 ms to 480 ms) in a patient who is pacemaker-dependent. There was associated fractionation of the ICD electrogram and T wave oversensing, leading to ventricular oversensing with resultant detection in the ventricular fibrillation rate zone. This was followed by shock therapy, even though the ventricular tachycardia rate was below the programmed detection rate of the ICD. The subsequent emergency treatment of the hyperkalemia normalized the electrogram, corrected the ventricular oversensing and arrhythmia, and restored rate-adaptive single-chamber ventricular pacing. PMID:18340383

Differential diagnosis of the 4th ventricular tumors

International Nuclear Information System (INIS)

Lee, Sang Woo; Lee, Jong Min; Kang, Moo Song; Kim, Chul Min; Kim, Chang Soo

1997-01-01

To determine by analysis of MR and CT findings the points of differentiation among 4th ventricular tumors, especially the change of shape of the 4th ventricle caused by the site at which 4th ventricular tumors originate. The authors retrospectively analyzed and compared the CT(n=5) and MRI(n=12) findings of 13 pathologically proven 4th ventricular tumors comprising six medulloblastomas three ependymomas(4 cases) and three choroids plexus papillomas. On axial MRI medulloblastomas showed anterior and anterolateral CSF-clefts between the tumor mass and the 4th ventricular wall in one and five cases, respectively; on sagittal MRI, anterior beaking of the upper 4th ventricle was seen. Two ependymomas showed posterolateral CSF-cleft on axial MRI and posterior beaking of the upper 4th ventricle on sagittal MRI. Two ependymomas and all choroids plexus papillomas showed anterior, posterior and lateral CSF-clefts on axial MRI, and anterior and posterior beakings of the upper 4th ventricle on sagittal MRI. On Gd-DTPA enhanced T1WI, all medulloblastomas and ependymomas showed inhomogeneous enhancement, and all choroids plexus papillomas showed homogeneous enhancement. On CT, tow choroids plexus papillomas showed dense calcifications. The differential diagnosis of 4th ventricular tumors can be preoperatively suggested by analysis of findings such as a CSF-cleft between the tumor mass and the 4th ventricular wall on axial MR and CT images, the shape of the upper 4th ventricle on sagittal MRI, contrast enhancement pattern, necrosis and cyst, and CSF seeding

Usefulness of ventricular endocardial electric reconstruction from body surface potential maps to noninvasively localize ventricular ectopic activity in patients

Science.gov (United States)

Lai, Dakun; Sun, Jian; Li, Yigang; He, Bin

2013-06-01

As radio frequency (RF) catheter ablation becomes increasingly prevalent in the management of ventricular arrhythmia in patients, an accurate and rapid determination of the arrhythmogenic site is of important clinical interest. The aim of this study was to test the hypothesis that the inversely reconstructed ventricular endocardial current density distribution from body surface potential maps (BSPMs) can localize the regions critical for maintenance of a ventricular ectopic activity. Patients with isolated and monomorphic premature ventricular contractions (PVCs) were investigated by noninvasive BSPMs and subsequent invasive catheter mapping and ablation. Equivalent current density (CD) reconstruction (CDR) during symptomatic PVCs was obtained on the endocardial ventricular surface in six patients (four men, two women, years 23-77), and the origin of the spontaneous ectopic activity was localized at the location of the maximum CD value. Compared with the last (successful) ablation site (LAS), the mean and standard deviation of localization error of the CDR approach were 13.8 and 1.3 mm, respectively. In comparison, the distance between the LASs and the estimated locations of an equivalent single moving dipole in the heart was 25.5 ± 5.5 mm. The obtained CD distribution of activated sources extending from the catheter ablation site also showed a high consistency with the invasively recorded electroanatomical maps. The noninvasively reconstructed endocardial CD distribution is suitable to predict a region of interest containing or close to arrhythmia source, which may have the potential to guide RF catheter ablation.

chronic sleep deprevation and ventricular arrhythmias: effect of symphatic nervous system

Directory of Open Access Journals (Sweden)

Samira Choopani

2016-04-01

Full Text Available Introduction: We assessed the effect of chronic sleep deprivation on incidence of ischemia/reperfusion-induced ventricular arrhythmias (ventricular tachycardia and ventricular fibrillation and the role of the sympathetic nervous system in this respect. Material and methods: Rats were randomly divided into four groups; 1 ischemia/reperfusion group (IR: 30 minutes ischemia followed by 60 minutes reperfusion was induced, 2 control group (CON: rats has been placed in large multiple platforms for 72h prior to ischemia and reperfusion, 3 Chronic sleep deprivation group( SD: 72h sleep deprivation was induced by using small  multiple platform prior to ischemia and reperfusion, 4 Sympathectomy group (SYM: chemical sympathectomy was done 24h before to chronic sleep deprivation and then underwent ischemia and reperfusion. The heart isolated and perfused by langendorff apparatus. After thoracotomy and aorta cannulation, the hearts perfused in the langendorff apparatus using krebs-Henseleit buffer. Hearts were allowed to recovery for 15 min. After recovery period, 15 minutes was considered as baseline prior to 30 minutes ischemia followed by 60 minutes reperfusion.Tow thin stainless stell electrodes fixed on the ventricular apex and right atrium for recording the lead II of electrocardiogram (ECG.Results: There were no significant differences between heart rates between groups, and ventricular tachycardia significantly increased in chronic sleep deprivation group As compared with IR group in ischemia period. Sympathectomy significantly reduced ventricular tachycardia incidence when compared with SD. There is no difference in incidence of ventricular tachycardia between control group and IR group. The incidence of ventricular fibrillation during early reperfusion was significantly augmented (P<0.05 in sleep deprivation group as compared with IR group and Sympathectomy significantly could reverse ventricular fibrillation incidence to IR group level as

Patterns of left ventricular remodeling among patients with essential and secondary hypertension.

Science.gov (United States)

Radulescu, Dan; Stoicescu, Laurentiu; Buzdugan, Elena; Donca, Valer

2013-12-01

High blood pressure causes left ventricular hypertrophy, which is a negative prognostic factor among hypertensive patients. To assess left ventricular geometric remodeling patterns in patients with essential hypertension or with hypertension secondary to parenchymal renal disease. We analyzed data from echocardiograms performed in 250 patients with essential hypertension (150 females) and 100 patients with secondary hypertension (60 females). The interventricular septum and the left ventricular posterior wall thickness were measured in the parasternal long-axis. Left ventricular mass was calculated using the Devereaux formula. The most common remodeling type in females and males with essential hypertension were eccentric and concentric left ventricular hypertrophy (cLVH), respectively. Among patients with secondary arterial hypertension, cLVH was most commonly observed in both genders. The prevalence of left ventricular hypertrophy was higher among patients with secondary hypertension. The left ventricular mass index and the relative left ventricular wall thickness were higher in males and also in the secondary hypertension group. Age, blood pressure values and the duration of hypertension, influenced remodeling patterns. We documented a higher prevalence of LVH among patients with secondary hypertension. The type of ventricular remodeling depends on gender, age, type of hypertension, blood pressure values and the duration of hypertension.

Ventricular Septal Defect (VSD)

Science.gov (United States)

... Call your doctor if your baby or child: Tires easily when eating or playing Is not gaining ... heart procedures. Risk factors Ventricular septal defects may run in families and sometimes may occur with other ...

Epicardial deployment of right ventricular disk during perventricular device closure in a child with apical muscular ventricular septal defect

Directory of Open Access Journals (Sweden)

Nageswara Rao Koneti

2013-01-01

Full Text Available We report a successful perventricular closure of an apical muscular ventricular septal defect (mVSD by a modified technique. An eight-month-old infant, weighing 6.5 kilograms, presented with refractory heart failure. The transthoracic echocardiogram showed multiple apical mVSDs with the largest one measuring 10 mm. perventricular device closure using a 12 mm Amplatzer mVSD occluder was planned. The left ventricular disk was positioned approximating the interventricular septum; however, the right ventricular (RV disk was deployed on the free wall of the RV due to an absent apical muscular septum and a small cavity at the apex. The RV disk of the device was covered using an autologous pericardium. His heart failure improved during follow-up.

Right ventricular functional analysis utilizing first pass radionuclide angiography for pre-operative ventricular assist device planning: a multi-modality comparison.

Science.gov (United States)

Avery, Ryan; Day, Kevin; Jokerst, Clinton; Kazui, Toshinobu; Krupinski, Elizabeth; Khalpey, Zain

2017-10-10

Advanced heart failure treated with a left ventricular assist device is associated with a higher risk of right heart failure. Many advanced heart failures patients are treated with an ICD, a relative contraindication to MRI, prior to assist device placement. Given this limitation, left and right ventricular function for patients with an ICD is calculated using radionuclide angiography utilizing planar multigated acquisition (MUGA) and first pass radionuclide angiography (FPRNA), respectively. Given the availability of MRI protocols that can accommodate patients with ICDs, we have correlated the findings of ventricular functional analysis using radionuclide angiography to cardiac MRI, the reference standard for ventricle function calculation, to directly correlate calculated ejection fractions between these modalities, and to also assess agreement between available echocardiographic and hemodynamic parameters of right ventricular function. A retrospective review from January 2012 through May 2014 was performed to identify advanced heart failure patients who underwent both cardiac MRI and radionuclide angiography for ventricular functional analysis. Nine heart failure patients (8 men, 1 woman; mean age of 57.0 years) were identified. The average time between the cardiac MRI and radionuclide angiography exams was 38.9 days (range: 1 - 119 days). All patients undergoing cardiac MRI were scanned using an institutionally approved protocol for ICD with no device-related complications identified. A retrospective chart review of each patient for cardiomyopathy diagnosis, clinical follow-up, and echocardiogram and right heart catheterization performed during evaluation was also performed. The 9 patients demonstrated a mean left ventricular ejection fraction (LVEF) using cardiac MRI of 20.7% (12 - 40%). Mean LVEF using MUGA was 22.6% (12 - 49%). The mean right ventricular ejection fraction (RVEF) utilizing cardiac MRI was 28.3% (16 - 43%), and the mean RVEF calculated by

Estudo da função ventricular na técnica de plicatura da parede livre do ventrículo esquerdo em cães Left ventricular function after plication of the left ventricular free wall in dogs

Directory of Open Access Journals (Sweden)

James Newton Bizetto Meira de Andrade

2004-06-01

Full Text Available OBJETIVO: Avaliar os efeitos da técnica na função ventricular esquerda em cães hígidos e com cardiomiopatia dilatada induzida pela doxorrubicina. MÉTODO: De 13 cães, oito receberam doxorrubicina até que a fração de encurtamento (FE fosse menor que 20%. Destes, quatro animais e os cinco não induzidos foram submetidos à plicatura da parede livre do ventrículo esquerdo (PPLVE. Os demais cães não foram operados. Foram avaliados débito cardíaco (DC, pressão arterial, exame físico, eletrocardiografia, sistema "Holter" e ecocardiografia, por 180 dias. RESULTADOS: Houve redução do volume ventricular esquerdo. Os cães induzidos melhoraram após a operação e a fração de ejeção (FEj retornou aos valores normais para a espécie. O DC e a FE aumentaram após a operação. Um cão foi a óbito. Nos cães não operados, a FE diminuiu e foram a óbito em torno de 40 dias após a indução; nos cães não induzidos, esta não se alterou. Houve extra-sístoles ventriculares, que se resolveram espontaneamente. CONCLUSÕES: A PPLVE sem circulação extracorpórea reduz o volume ventricular esquerdo e melhora a função cardíaca dos cães com cardiomiopatia dilatada induzida pela doxorrubicina, demonstrando baixa morbidade e mortalidade tardia.OBJECTIVE: We tested a new surgical technique, the plication of the left ventricular free wall, to reduce left ventricular area and volume and improve left ventricular systolic function, without using a cardiopulmonary bypass. METHODS: Dilated cardiomyopathy was induced in eight dogs by the injection of doxorubicin. Plication of the left ventricular free wall was performed in four dogs with induced cardiomyopathy and in five control dogs. Two dogs not submitted to surgery. The other two dogs died during the induction phase. Cardiac output, 2-dimensional and M-mode echocardiography, arterial blood pressure and electrocardiography were recorded over a 180 days period. Ambulatory electrocardiography

Associations of Blood Pressure Dipping Patterns With Left Ventricular Mass and Left Ventricular Hypertrophy in Blacks: The Jackson Heart Study.

Science.gov (United States)

Abdalla, Marwah; Caughey, Melissa C; Tanner, Rikki M; Booth, John N; Diaz, Keith M; Anstey, D Edmund; Sims, Mario; Ravenell, Joseph; Muntner, Paul; Viera, Anthony J; Shimbo, Daichi

2017-04-05

Abnormal diurnal blood pressure (BP), including nondipping patterns, assessed using ambulatory BP monitoring, have been associated with increased cardiovascular risk among white and Asian adults. We examined the associations of BP dipping patterns (dipping, nondipping, and reverse dipping) with cardiovascular target organ damage (left ventricular mass index and left ventricular hypertrophy), among participants from the Jackson Heart Study, an exclusively black population-based cohort. Analyses included 1015 participants who completed ambulatory BP monitoring and had echocardiography data from the baseline visit. Participants were categorized based on the nighttime to daytime systolic BP ratio into 3 patterns: dipping pattern (≤0.90), nondipping pattern (>0.90 to ≤1.00), and reverse dipping pattern (>1.00). The prevalence of dipping, nondipping, and reverse dipping patterns was 33.6%, 48.2%, and 18.2%, respectively. In a fully adjusted model, which included antihypertensive medication use and clinic and daytime systolic BP, the mean differences in left ventricular mass index between reverse dipping pattern versus dipping pattern was 8.3±2.1 g/m 2 ( P pattern versus dipping pattern was -1.0±1.6 g/m 2 ( P =0.536). Compared with participants with a dipping pattern, the prevalence ratio for having left ventricular hypertrophy was 1.65 (95% CI, 1.05-2.58) and 0.96 (95% CI, 0.63-1.97) for those with a reverse dipping pattern and nondipping pattern, respectively. In this population-based study of blacks, a reverse dipping pattern was associated with increased left ventricular mass index and a higher prevalence of left ventricular hypertrophy. Identification of a reverse dipping pattern on ambulatory BP monitoring may help identify black at increased risk for cardiovascular target organ damage. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Impacto da hipertensão arterial no remodelamento ventricular, em pacientes com estenose aórtica

Directory of Open Access Journals (Sweden)

João Carlos Hueb

2011-09-01

Full Text Available FUNDAMENTO: A hipertrofia ventricular esquerda (HVE é comum em pacientes com hipertensão arterial sistêmica (HAS e estenose aórtica (EAo e, com certa frequência, encontramos associação entre estas patologias. Mas, em tal situação, não está clara a importância de cada uma na HVE. OBJETIVO: 1 - Avaliar em pacientes portadores de EAo, submetidos previamente a estudo ecocardiográfico, a magnitude da HVE, nos casos de EAo isolada e associada à HAS; 2 - Avaliar o padrão de remodelamento geométrico nas duas situações. MÉTODOS: Estudo retrospectivo, observacional e transversal, incluindo 298 pacientes consecutivos, com EAo ao ecocardiograma. HVE foi considerada para massa miocárdica > 224g em homens e > 162g em mulheres. Os pacientes foram classificados como portadores de EAo leve (gradiente máximo 50,0 mmHg, além disso, foram separados em dois subgrupos: com e sem HAS. RESULTADOS: Nos três níveis de lesão aórtica, a massa ventricular esquerda foi maior na EAo associada à HAS do que na EAo isolada (EAo leve: 172 ± 45 vs 223 ± 73g, p < 0,0001; EAo moderada: 189 ± 77 vs 245 ± 81g, p = 0,0313; EAo grave: 200 ± 62 vs 252 ± 88g, p = 0,0372. Presença de HAS esteve associada a maior risco de HVE (OR = 2,1,IC95%:1,2-3,6; p = 0,012. Pacientes com EAo grave e HAS apresentaram predomínio de hipertrofia concêntrica, quando comparados com aqueles normotensos (p = 0,013. CONCLUSÃO: Em pacientes com EAo, a presença de HAS foi um fator adicional de aumento da massa ventricular esquerda, interferindo também na geometria ventricular.

Right Ventricular Ejection Fraction using ECG-Gated First Pass Cardioangiography

Energy Technology Data Exchange (ETDEWEB)

Moon, Young Hee; Lee, Hae Giu; Lee, Sung Yong; Park, Suk Min; Chung, Soo Kyo; Yim, Jeong Ik; Bahk, Yong Whee; Shinn, Kyung Sub; Kim, Young Gyun; Kwon, Soon Seog [Catholic University College of Medicine, Seoul (Korea, Republic of)

1993-03-15

Radionuclide cardioangiography has been widely applied and has played major roles in moninvasive assessment of cardiac function. Three techniques, first-pass gated first and gated equilibrium methods have commonly been used to evaluate right ventricular ejection fraction which usually abnormal in the patients with cardiopulmonary disease. It has been known that the gated first pass method is most accurate method among the three techniques in assessment of fight ventricular ejection fraction. The radionuclide right ventricular ejection fraction values were determined in 13 normal subjects and in 15 patients with chronic obstructive pulmonary disease by the gated first pass method and compared with those of the first pass method because there has been no published data of fight ejection fraction by the gated first pass method were compared with the defects from the pulmonary function test performed in the patients with chronic obstructive pulmomary disease. The results were as follows; 1) The values of fight ventricular ejection fraction by the gated first pass method were 50.1 +- 6.1% in normal subjects and 38.5 +- 8.5 in the patients with chronic obstructive pulmonary disease. There was statistically significant difference between the right ventricular ejection fraction of each of the two groups (p<0.05) 2) The right ventricular ejection fraction by the gated first pass method was not linearly correlated ith FEV{sub 1}, VC. DLCO. and FVC as well as P{sub a}O2 and P{sub a}CO2 of the patients with chronic obstructive pulmonary disease. We concluded that right ventricular ejection fraction by the gated first pass method using radionuclide cardioangiography may be useful in clinical assessment of the right ventricular function.

Quantitative measurement of ventricular dilatation on CT scan

International Nuclear Information System (INIS)

Okita, Naoshi; Mochizuki, Hiroshi; Takase, Sadao

1985-01-01

Cerebral atrophy might be judged from the ventricular dilatation with some indices, calculated from various ventricular width. But, there is no general agreement on what index is the most reliable. In this paper, we attempted to establish the index, easy to measure and most reliable. Our method is as follow. 1) We carried out the CT scan (EMI 1010) on 89 neurologically intact patients. Scans were parallel to orbito-meatal line (OML), and were 10 mm in thickness. On CT scan films, various width, area of anterior horns and area of bodies of lateral ventricles were measured. Measurement about the anterior horns of lateral ventricles were carried out on image the most clearly showed the foramen of Monro. And measurements about the bodies of lateral ventricles were on image, 20 mm above the image of anterior horn. Correlations of various width and areas were calculated. Then we proposed new indices with high correlations (over 0.9) with ventricular area; Anterior horn CVI (Cerebro-Ventricular Index) and Body CVI. 2) Patients with myotonic dystrophy show cerebral atrophy. We carried out the CT scan (GECT/T 8800) on 17 myotonic dystrophy patients and 30 controls. Between the two groups, age and sex were almost matched. In the two groups, we calculated our new indices as well as various indices which have been reported; Huckman number, Bifrontal CVI, Bicaudal CVI, Anterior horn index, Hirajima's index, and Cella-media index. The data were analyzed statistically. The ventricular dilatation of myotonic dystrophy patients is more definite with Anterior horn CVI, Bicaudal CVI and Body CVI (p<0.01). These indices have higher correlations with the ventricular area (about 0.9). (J.P.N.)

Assessment of ventricular function by radionuclide ventriculography in hyperthyroidism

International Nuclear Information System (INIS)

Dong Weiyu; He Pinyu; Zhuang Weite

1996-01-01

Left ventricular(LV) and right ventricular(RV) function were determined using radionuclide ventriculography in 50 patients with hyperthyroidism. LVEF, LVPFR, SV of the hyperthyroidism group were decreased in comparison with the normal group (P<0.01), whereas CO of the hyperthyroidism patients were higher than that of normal (P<0.01). Except LVPER, the LVEF, SV had significant difference between two groups. Compared to normal group, RVEF, RVPER, RVPFR were also decreased (P<0.01). Besides 30 cases of the hyperthyroidism were examined by impedance cardiogram (ICG) and impedance pulmonary rheogram (IPR), all showed closely correlation with the parameters determined by ventriculography. There was the involvement of right ventricular function insufficiency, especially in ejection phase. When compared with pre-therapy, pos-therapy cases showed significant improvement in EF, PER, PFR of left and right ventricular

Noninvasive assessment of right ventricular wall motion by radionuclide cardioangiography

International Nuclear Information System (INIS)

Nishimura, Tsunehiko; Uehara, Toshiisa; Naito, Hiroaki; Hayashida, Kohei; Kozuka, Takahiro

1981-01-01

Radionuclide cardioangiography is a useful method to evaluate the left ventricular wall motion in various heart diseases. It has been also attempted to assess the right ventricular wall motion simultaneously by radionuclide method. In this study, using the combination of first-pass (RAO 30 0 ) and multi-gate (LAO 40 0 ) method, the site of right vetricle was classified in five. (1 inflow, 2 sinus, 3 outflow, 4 septal, 5 lateral) and the degree of wall motion was classified in four stages (dyskinesis, akinesis, hypokinesis, normal) according to the AHA committee report. These methods were applied clinically to forty-eight patients with various heart diseases. In the cases with right ventricular pressure or volume overload such as COLD, pulmonary infarction, the right ventricle was dilated and the wall motion was reduced in all portions. Especially, in the cases with right ventricular infarction, the right ventricular wall motion was reduced in the infarcted area. The findings of radionuclide method were in good agreement with those of contrast right ventriculography or echocardiography. In conclusion, radionuclide cardioangiography is a useful and noninvasive method to assess not only the left but also the right ventricular wall motion. (author)

Interdependence of right ventricular systolic function and left ventricular filling and its association with outcome for patients with pulmonary hypertension.

Science.gov (United States)

Motoji, Yoshiki; Tanaka, Hidekazu; Fukuda, Yuko; Sano, Hiroyuki; Ryo, Keiko; Imanishi, Junichi; Miyoshi, Tatsuya; Sawa, Takuma; Mochizuki, Yasuhide; Matsumoto, Kensuke; Emoto, Noriaki; Hirata, Ken-ichi

2015-04-01

Although impaired right ventricular (RV) performance has been associated with adverse outcomes for pulmonary hypertension (PH) patients, the relationship between bi-ventricular interdependence and outcomes is not yet fully understood. We studied 96 PH patients. RV systolic function was assessed by means of RV free-wall longitudinal speckle-tracking strain (RV-free), and left ventricular (LV) filling as early diastolic transmitral flow velocity (TMF-E). RV-free ≤19 % and TMF-E functional class IV and brain natriuretic peptide >150 pg/dl (χ(2) = 1.2) was improved by the addition of RV-free (χ(2) = 5.5, p = 0.04) as well as of TMF-E (χ(2) = 11.5, p = 0.01). In conclusions, RV systolic function was shown to correlate significantly with LV filling in PH patients. In addition, not only assessment of RV systolic function, but also of a combined bi-ventricular parameter comprising RV systolic function and LV filling may well have clinical implications for more successful management of PH patients.

Determinación de los valores normales del índice de tei (índice de performance miocárdico y otros parámetros ecocardiográficos doppler de la función ventricular izquierda en caninos sanos

Directory of Open Access Journals (Sweden)

Iván Álvarez

2010-06-01

Full Text Available La falla cardiaca está relacionada con anormalidades en la contracción y relajación ventricular. Estudios recientes han mostrado que en la mayoría de los pacientes con insuficiencia cardiaca coexisten alteraciones de la función sistólica y diastólica, y en algunos casos la función sistólica es normal pero la falla cardiaca es generada por disfunción ventricular diastólica. El índice de performance miocárdico (tiempo de contracción isovolumétrica sumado al tiempo de eyección ventricular dividido el tiempo de eyección, “Índice de Tei” ha sido descrito como una manera más efectiva para el análisis de la Disfunción Miocárdica Global que otros parámetros de función sistólica y diastólica. Con base en estos antecedentes, los autores determinaron el valor normal del índice de Tei para el ventrículo izquierdo en caninos sanos en la ciudad de Bogotá (2.600 msnm con el objeto de utilizar dicho valor como índice de la función sistodiastólica. Se obtuvo un valor medio de 0,33 con un desvío estándar de 0,10. Asimismo pudo verificarse que no existe correlación con la frecuencia cardiaca, peso corporal ni con la fracción de eyección ventricular izquierdo (P<0,05.

Ventricular rhythm in atrial fibrillation under anaesthetic infusion with propofol

International Nuclear Information System (INIS)

Cervigón, R; Moreno, J; Pérez-Villacastín, J; Reilly, R B; Castells, F

2009-01-01

Changes in patients' autonomic tone and specific pharmacologic interventions may modify the ventricular response (actual heart rate) during atrial fibrillation (AF). Hypnotic agents such as propofol may modify autonomic balance as they promote a sedative state. It has been shown that propofol slightly slows atrial fibrillatory activity, but the net global effect on the ventricular response remains unknown. We aimed to evaluate in patients in AF the effect of a propofol bolus on the ventricular rate and regularity at ECG. We analysed the possible relation with local atrial fibrillatory activities, as ratios between atrial and ventricular rates (AVRs), analysing atrial activity from intracardiac electrograms at the free wall of the right and left atria and at the interatrial septum. We compared data at the baseline and after complete hypnosis. Propofol was associated with a more homogeneous ventricular response and lower AVR values at the interatrial septum

Bidirectional ventricular tachycardia of unknown etiology

International Nuclear Information System (INIS)

Ali, M.; Khan, J.A.; Masood, T.; Shamsi, F.; Dero, M.H.; Khan, S.

2013-01-01

A 45 years old male presented to the emergency department with palpitations, headache and apprehension. His electrocardiogram revealed bidirectional ventricular tachycardia. He remained vitally stable and responded to intravenous beta-blocker. Initially digitalis toxicity was suspected but history was negative for digitalis intake. The cause remained unidentified in patient despite detailed investigations. During a short follow-up (of 6 months) he remained asymptomatic and no cause was further identified during this period. Some other unseen causes of bidirectional ventricular tachycardia need to be explored. (author)

An Incidentally Detected Right Ventricular Pseudoaneurysm

Directory of Open Access Journals (Sweden)

Vamsi C. Gaddipati

2017-01-01

Full Text Available Ventricular pseudoaneurysm is an uncommon, potentially fatal complication that has been associated with myocardial infarction, cardiac surgery, chest trauma, and infectious processes. Diagnosis can be challenging, as cases are rare and slowly progressing and typically lack identifiable features on clinical presentation. As a result, advanced imaging techniques have become the hallmark of identification. Ahead, we describe a patient who presents with acute decompensated heart failure and was incidentally discovered to have a large right ventricular pseudoaneurysm that developed following previous traumatic anterior rib fracture.

What is the clinical significance of ventricular mural antagonism?

DEFF Research Database (Denmark)

Lunkenheimer, Paul P; Niederer, Peter; Stephenson, Robert S

2018-01-01

alignment, thus deviating from the prevailing tangential orientation. Upon contraction, they produce, in addition to a tangential force, a radial force component that counteracts ventricular constriction and aids widening of the ventricular cavity. In experimental studies, we have provided evidence...... for the existence of such forces, which are auxotonic in nature. This is in contrast to the tangentially aligned myocytes that produce constrictive forces, which are unloading in nature. The ventricular myocardium is, therefore, able to function in an antagonistic fashion, with the prevailing constrictive forces...

A consideration of a measuring point of ventricular dilatation on CT scanning

International Nuclear Information System (INIS)

Kuno, Koichi; Miyake, Kazuo

1980-01-01

Ventricular dilatation has been judged by pneumo-ventricurography, pneumo-encepharography and carotid angiography (CAG), though all these procedures are very uncomfortable for patients. On the other hand, the CT scan is very easy as a follow-up study of ventricular dilatation for a weak patient. We carried out the CT scan (Hitachi CT-H 250 Scanner, NaI detector) and CAG on 84 cases. The ventricular dilatation was judged by the degree of outstretch of the strio-thalamic vein on an AP view of the phrebogram, classified into 3 types. For all three types classified by the phrebogram, we studied various measuring points of the ventricle on the CT scan. The portions measured on the CT scan were: (1) the frontal cerebro-ventricular index (F-CVI), (2) the bicaudate cerebro-ventricular index (Bicaud-CVI), and (3) the maximum Monro's cerebro-ventricular index (M-CVI), the width of the frontal horn, and the thickness of the ventricular body. The following results were obtained: (1) In measuring the ventricular size on the CT scan, the most interrelated point with the ventricular dilatation is the M-CVI - the ratio of the largest width of the body through the Monro foramen to the width of the brain. In this case, however, the width of the frontal horn and of the body should also be considered. (2) Voltage and electric current changed the EMI-number, but did not alter the measuring value. In this case, the width and the level should be kept constant. (3) The group with the marked ventricular dilatation has a larger value of the CT scan than its value of GAG. (4) The normal value of the M-CVI is 24 +- 3%, moreover, the width of the frontal horn is less than 10 mm, and the thickness of the ventricular body is less than 17 mm. (author)

Effect of Hemodialysis on Left and Right Ventricular Volume and Function

International Nuclear Information System (INIS)

Han, Jin Suk; Koh, Chang Soon

1985-01-01

With the improvement of hemodialysis, the course of thc discase in patient with endstage renal disease has been clearly improved. Nevertheless, among several shortcomings to our present mode of renal replacement therapy, cardiovascular complications have been the leading cause of morbidity and mortality. Several factors such as anemia, arteriovenous shunting of blood, intermittent extracorporeal circulation and hypertension may be contributing. But little is known about the quantitative cardiac hemodynamic characteristics occurred during hemodialysis. The purpose of this study is to observe the sequential hemodynamic changes before, during and after the hemodialysis and to investigate: reliable parameters in the detection of ventricular dysfunction. In the present study, equilibrium radionuclide cardiac angiography was performed and left and right ventricular volume indices, ejection phase indices of both ventricular, performance were measured in the 16 stable patients with chronic renal failure treated with maintenance hemodialysis sequentially i.e. before, during (carly and late phase) and after the hemodialysis. The results obtained were as follows; 1) The indices of the left ventricular function were not changed during the hemodialysis but increased after the hemodialysis. 2) The indices of the right ventricular function(EF, SVI) were significantly decreased in the early phase (15, 30 minutes after starting extracorporeal circulation) but recovered after the hemodialysis, 3) The ratio of right ventricular to left ventricular ejection fraction was significantly decreased in the early phase and the lung volume indices were significantly increased at the same phase. As a conclusion, hemodialysis improves left ventricular function maybe du to increased contractility, and effects on the right ventricular function maybe due to the increased lung volume in the early phase of hemodialysis.

Effect of Hemodialysis on Left and Right Ventricular Volume and Function

Energy Technology Data Exchange (ETDEWEB)

Han, Jin Suk; Koh, Chang Soon [Seoul National University College of Medicine, Seoul (Korea, Republic of)

1985-09-15

With the improvement of hemodialysis, the course of thc discase in patient with endstage renal disease has been clearly improved. Nevertheless, among several shortcomings to our present mode of renal replacement therapy, cardiovascular complications have been the leading cause of morbidity and mortality. Several factors such as anemia, arteriovenous shunting of blood, intermittent extracorporeal circulation and hypertension may be contributing. But little is known about the quantitative cardiac hemodynamic characteristics occurred during hemodialysis. The purpose of this study is to observe the sequential hemodynamic changes before, during and after the hemodialysis and to investigate: reliable parameters in the detection of ventricular dysfunction. In the present study, equilibrium radionuclide cardiac angiography was performed and left and right ventricular volume indices, ejection phase indices of both ventricular, performance were measured in the 16 stable patients with chronic renal failure treated with maintenance hemodialysis sequentially i.e. before, during (carly and late phase) and after the hemodialysis. The results obtained were as follows; 1) The indices of the left ventricular function were not changed during the hemodialysis but increased after the hemodialysis. 2) The indices of the right ventricular function(EF, SVI) were significantly decreased in the early phase (15, 30 minutes after starting extracorporeal circulation) but recovered after the hemodialysis, 3) The ratio of right ventricular to left ventricular ejection fraction was significantly decreased in the early phase and the lung volume indices were significantly increased at the same phase. As a conclusion, hemodialysis improves left ventricular function maybe du to increased contractility, and effects on the right ventricular function maybe due to the increased lung volume in the early phase of hemodialysis.

Left ventricular pressure and volume data acquisition and analysis using LabVIEW.

Science.gov (United States)

Cassidy, S C; Teitel, D F

1997-03-01

To automate analysis of left ventricular pressure-volume data, we used LabVIEW to create applications that digitize and display data recorded from conductance and manometric catheters. Applications separate data into cardiac cycles, calculate parallel conductance, and calculate indices of left ventricular function, including end-systolic elastance, preload-recruitable stroke work, stroke volume, ejection fraction, stroke work, maximum and minimum derivative of ventricular pressure, heart rate, indices of relaxation, peak filling rate, and ventricular chamber stiffness. Pressure-volume loops can be graphically displayed. These analyses are exported to a text-file. These applications have simplified and automated the process of evaluating ventricular function.

Independence of intrapericardial right and left ventricular performance in septic pulmonary hypertension

International Nuclear Information System (INIS)

Boeck, J.C.; Eichstaedt, H.; Barker, B.C.; Lewis, F.R.; Lim, A.D.; Pollycove, M.

1990-01-01

To study the effect of septic pulmonary hypertension on right/left ventricular intrapericardial interactions thirteen trauma patients, seven septic and six nonseptic controls, were compared. Ventricular volumes were derived from firstpass or gated equilibrium radionuclide angiocardiography, and related to body surface area. Systemic and pulmonary pressures were measured invasively. Pulmonary arterial pressure was significantly increased in the sepsis group. Although right ventricular end-diastolic volumes were higher in sepsis, left ventricular end-diastolic volumes were not decreased. In terms of intrapericardial right/left ventricular interactions these results indicate that the right and left ventricles operate independently in septic pulmonary hypertension. (orig.) [de

Ventricular dyssynchrony as a cause of structural disease in the heart of Dorper sheep

Directory of Open Access Journals (Sweden)

J. Ker

2004-11-01

Full Text Available Ventricular dyssynchrony is a disturbance of the normal, organized electromechanical coupling of the two ventricles. This condition has many causes, such as left bundle branch block, ventricular preexcitation, right ventricular pacing and right ventricular premature ventricular complexes (PVCs. Ventricular dyssynchrony has many adverse haemodynamic effects on the left ventricle and we wanted to know whether these adverse haemodynamic effects might have any structural consequences on the left ventricles of such hearts. Six healthy Dorper wethers were subjected to numerous right ventricular PVCs to induce ventricular dyssynchrony in order to determine whether any structural consequences will occur in the left ventricles of these hearts. Myocarditis in the musculature of the left ventricles of all six these hearts was seen.

Measurement of the ventricular system with computed tomography of the brain

International Nuclear Information System (INIS)

Takayama, Makoto

1979-01-01

In order to establish the diagnostic criteria of a normal ventricular system from the data provided by CT images, including those showing physiological ventricular delatation with age, we have measured, using the ACTA 0100 scanner, the ventricular systems of 348 cases on CT images which were diagnosed as ''nornal'' by several radiologists. We measured the following four widths of the ventricular system: A) width to tips of the frontal horns of the lateral ventricles. B) width at midpoint of the frontal horns of the lateral ventricles, C) width of the third ventricle, and D) width of the body of the lateral ventricles. Measurements were made directly on Polaroid prints, and then the mean and the standard deviation were calculated in each age group. These measurements suggest the following ranges of normal ventricular parameters: A) 38.3 mm or less, B) 20.2 mm or less, C) 6.6 mm or less, and D) 47.0 mm or less. The measurements of the ventricular system showed a steady increase with age. The ventricular systems of 193 cases diagnosed to have no intracranial mass lesion were also measured in different age and symptom groups. Measurements of various parts of the ventricular system on the 193 cases also indicated and increase with age; however, they showed no significant difference in any symptom groups: the convulsion group, the cerebrovascular attack group, the indefinite complaint group (including headaches), the dementia group, the degenerative disease group, or any other. (author)

Impact of aortic prosthesis-patient mismatch on left ventricular mass regression.

Science.gov (United States)

Alassal, Mohamed A; Ibrahim, Bedir M; Elsadeck, Nabil

2014-06-01

Prostheses used for aortic valve replacement may be small in relation to body size, causing prosthesis-patient mismatch and delaying left ventricular mass regression. This study examined the effect of prosthesis-patient mismatch on regression of left ventricular mass after aortic valve replacement. We prospectively studied 96 patients undergoing aortic valve replacement between 2007 and 2012. Mean and peak gradients and indexed effective orifice area were measured by transthoracic echocardiography at 3 and 6 months postoperatively. Patient-prosthesis mismatch was defined as indexed effective orifice area ≤0.85 cm(2)·m(-2). Moderate prosthesis-patient mismatch was present in 25% of patients. There were no significant differences in demographic and operative data between patients with and without prosthesis-patient mismatch. Left ventricular dimensions, posterior wall thickness, transvalvular gradients, and left ventricular mass decreased significantly after aortic valve replacement in both groups. The interventricular septal diameter and left ventricular mass index regression, and left ventricular ejection fraction were better in patients without prosthesis-patient mismatch. There was a significant positive correlation between the postoperative indexed effective orifice area of each valve prosthesis and the rate of left ventricular mass regression. Prosthesis-patient mismatch leads to higher transprosthetic gradients and impaired left ventricular mass regression. A small-sized valve prosthesis does not necessarily result in prosthesis-patient mismatch, and may be perfectly adequate in patient with small body size. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Ventricular arrhythmias in the absence of structural heart disease.

Science.gov (United States)

Prystowsky, Eric N; Padanilam, Benzy J; Joshi, Sandeep; Fogel, Richard I

2012-05-15

Ventricular arrhythmia (VA) in structurally normal hearts can be broadly considered under non-life-threatening monomorphic and life-threatening polymorphic rhythms. Monomorphic VA is classified on the basis of site of origin in the heart, and the most common areas are the ventricular outflow tracts and left ventricular fascicles. The morphology of the QRS complexes on electrocardiogram is an excellent tool to identify the site of origin of the rhythm. Although these arrhythmias are common and generally carry an excellent prognosis, rare sudden death events have been reported. Very frequent ventricular ectopy may also result in a cardiomyopathy in a minority of patients. Suppression of VA may be achieved using calcium-channel blockers, beta-adrenergic blockers, and class I or III antiarrhythmic drugs. Radiofrequency ablation has emerged as an excellent option to eliminate these arrhythmias, although certain foci including aortic cusps and epicardium may be technically challenging. Polymorphic ventricular tachycardia (VT) is rare and generally occurs in patients with genetic ion channel disorders including long QT syndrome, Brugada syndrome, catecholaminergic polymorphic VT, and short QT syndrome. Unlike monomorphic VT, these arrhythmic syndromes are associated with sudden death. While the cardiac gross morphology is normal, suggesting a structurally normal heart, abnormalities exist at the molecular level and predispose them to arrhythmias. Another fascinating area, idiopathic ventricular fibrillation and early repolarization syndrome, are undergoing research for a genetic basis. Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Left cardiac sympathetic denervation for catecholaminergic polymorphic ventricular tachycardia

NARCIS (Netherlands)

Wilde, Arthur A. M.; Bhuiyan, Zahurul A.; Crotti, Lia; Facchini, Mario; de Ferrari, Gaetano M.; Paul, Thomas; Ferrandi, Chiara; Koolbergen, Dave R.; Odero, Attilio; Schwartz, Peter J.

2008-01-01

Catecholaminergic polymorphic ventricular tachycardia is a potentially lethal disease characterized by adrenergically mediated ventricular arrhythmias manifested especially in children and teenagers. Beta-blockers are the cornerstone of therapy, but some patients do not have a complete response to

Ventricular dysfunction in children with obstructive sleep apnea: radionuclide assessment

International Nuclear Information System (INIS)

Tal, A.; Leiberman, A.; Margulis, G.; Sofer, S.

1988-01-01

Ventricular function was evaluated using radionuclide ventriculography in 27 children with oropharyngeal obstruction and clinical features of obstructive sleep apnea. Their mean age was 3.5 years (9 months to 7.5 years). Conventional clinical assessment did not detect cardiac involvement in 25 of 27 children; however, reduced right ventricular ejection fraction (less than 35%) was found in 10 (37%) patients (mean: 19.5 +/- 2.3% SE, range: 8-28%). In 18 patients wall motion abnormality was detected. In 11 children in whom radionuclide ventriculography was performed before and after adenotonsillectomy, right ventricular ejection fraction rose from 24.4 +/- 3.6% to 46.7 +/- 3.4% (P less than 0.005), and in all cases wall motion showed a definite improvement. In five children, left ventricular ejection fraction rose greater than 10% after removal of oropharyngeal obstruction. It is concluded that right ventricular function may be compromised in children with obstructive sleep apnea secondary to adenotonsillar hypertrophy, even before clinical signs of cardiac involvement are present

Nuclear medical diagnostic with ventricular aneurysm

International Nuclear Information System (INIS)

Litter, H.

1987-01-01

In the diagnostic of ventricular aneurysms myocardial scintigraphy and above all radionuclide ventriculography (RNV) have special importance. Because of the non-invasive method and the as a result safe and easy use even with stress studies, RNV can provide a very valuable aid with aneurysm patients in early diagnosis, evaluation of the operability and as well as in the prognosis. It must be noted, however, that the differentiation of multivascular diseases and sometimes ventricular aneurysms can be difficult and the inclusion of an angiocardiograph as a radiological invasive examination procedure seems fitting. (orig./MG) [de

The wide range in-core neutron measurement system used in the Windscale AGR concluding experiments

International Nuclear Information System (INIS)

Goodings, A.; Budd, J.; Wilson, I.

1982-06-01

The Windscale AGR Concluding Experiments included a comparison of theoretical and experimental power transients and required measurements of neutron flux as a function of position and time within the reactor core. These measurements were specified to cover as wide as possible working range and had to be made against the in-core gamma background of up to 4 x 10 7 R(hr) - 1 . The detectors were required to operate in special, channels cooled by reactor inlet carbon dioxide and the overall system needed a response time such that it could follow transients with doubling times down to 2s with an accuracy of 2 or 3%. These problems were solved by the use of gas ion fission chambers operating in the current fluctuation or Campbelling mode with unusually low filling pressures and fitted with special trilaminax mineral insulated cables. Ten detectors were built and nine were installed in the reactor, three in each of three special stringers at different radial positions. The paper describes the specification against which this system was built, the design process for the detectors, and commissioning experiments together with some of the problems which were encountered. (U.K.)

Left ventricular function in chronic aortic regurgitation

International Nuclear Information System (INIS)

Iskandrian, A.S.; Hakki, A.H.; Manno, B.; Amenta, A.; Kane, S.A.

1983-01-01

Left ventricular performance was determined in 42 patients with moderate or severe aortic regurgitation during upright exercise by measuring left ventricular ejection fraction and volume with radionuclide ventriculography. Classification of the patients according to exercise tolerance showed that patients with normal exercise tolerance (greater than or equal to 7.0 minutes) had a significantly higher ejection fraction at rest (probability [p] . 0.02) and during exercise (p . 0.0002), higher cardiac index at exercise (p . 0.0008) and lower exercise end-systolic volume (p . 0.01) than did patients with limited exercise tolerance. Similar significant differences were noted in younger patients compared with older patients in ejection fraction at rest and exercise (both p . 0.001) and cardiac index at rest (p . 0.03) and exercise (p . 0.0005). The end-diastolic volume decreased during exercise in 60% of the patients. The patients with a decrease in volume were significantly younger and had better exercise tolerance and a larger end-diastolic volume at rest than did patients who showed an increase in volume. The mean corrected left ventricular end-diastolic radius/wall thickness ratio was significantly greater in patients with abnormal than in those with normal exercise reserve (mean +/- standard deviation 476 +/- 146 versus 377 +/- 92 mm Hg, p less than 0.05). Thus, in patients with chronic aortic regurgitation: 1) left ventricular systolic function during exercise was related to age, exercise tolerance and corrected left ventricular end-diastolic radius/wall thickness ratio, and 2) the end-diastolic volume decreased during exercise, especially in younger patients and patients with normal exercise tolerance or a large volume at rest

First in-core simultaneous measurements of nuclear heating and thermal neutron flux obtained with the innovative mobile calorimeter CALMOS inside the OSIRIS reactor

Energy Technology Data Exchange (ETDEWEB)

Lepeltier, Valerie; Bubendorff, Jacques; Carcreff, Hubert [Nuclear studies and reactor irradiation Service, CEA Saclay 91191 Gif sur Yvette (France); Salmon, Laurent [Thermalhydraulics and Fluid Mechanics Section, CEA Saclay 91191 Gif sur Yvette, (France)

2015-07-01

Nuclear heating inside a MTR reactor has to be known in order to design and to run irradiation experiments which have to fulfill target temperature constraints. This measurement is usually carried out by calorimetry. The innovative calorimetric system, CALMOS, has been studied and built in 2011 for the 70 MWth OSIRIS reactor operated by CEA. Thanks to a new type of calorimetric probe, associated to a specific displacement system, it provides measurements along the fissile height and above the core. This development required preliminary modelling and irradiation of mock-ups of the calorimetric probe in the ex-core area, where nuclear heating rate does not exceed 2 W.g{sup -1}. The calorimeter working modes, the different measurement procedures allowed with such a new probe, the main modeling and experimental results and expected advantages of this new technique have been already presented. However, these first in-core measurements were not performed beyond 6 W.g{sup -1}, due to an inside temperature limitation imposed by a safety authority requirement. In this paper, we present the first in-core simultaneous measurements of nuclear heating and conventional thermal neutron flux obtained by the CALMOS device at the 70 MW nominal reactor power. For the first time, this experimental system was operated in nominal in-core conditions, with nominal neutron flux up to 2.7 10{sup 14} n.cm{sup -2}.s{sup -1} and nuclear heating up to 12 W.g{sup -1}. A comprehensive measurement campaign carried out from 2013 to 2015 inside all accessible irradiation locations of the core, allowed to qualify definitively this new device, not only in terms of measurement ability but also in terms of reliability. After a brief reminder of the calorimetric cell configuration and displacement system specificities, first nuclear heating distributions at nominal power are presented and discussed. In order to reinforce the heating evaluation, a systematic comparison is made between results obtained by

Towards Early Detection and Risk Stratification of Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy

NARCIS (Netherlands)

Riele, A.S.J.M. te

2016-01-01

Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy (ARVD/C) is an inherited cardiomyopathy characterized by frequent ventricular arrhythmias and usually slowly progressive ventricular dysfunction. Since its initial description in 1982, sudden cardiac death (SCD) occurring in young and usually

Skin Sodium Concentration Correlates with Left Ventricular Hypertrophy in CKD.

Science.gov (United States)

Schneider, Markus P; Raff, Ulrike; Kopp, Christoph; Scheppach, Johannes B; Toncar, Sebastian; Wanner, Christoph; Schlieper, Georg; Saritas, Turgay; Floege, Jürgen; Schmid, Matthias; Birukov, Anna; Dahlmann, Anke; Linz, Peter; Janka, Rolf; Uder, Michael; Schmieder, Roland E; Titze, Jens M; Eckardt, Kai-Uwe

2017-06-01

The pathogenesis of left ventricular hypertrophy in patients with CKD is incompletely understood. Sodium intake, which is usually assessed by measuring urinary sodium excretion, has been inconsistently linked with left ventricular hypertrophy. However, tissues such as skin and muscle may store sodium. Using 23 sodium-magnetic resonance imaging, a technique recently developed for the assessment of tissue sodium content in humans, we determined skin sodium content at the level of the calf in 99 patients with mild to moderate CKD (42 women; median [range] age, 65 [23-78] years). We also assessed total body overhydration (bioimpedance spectroscopy), 24-hour BP, and left ventricular mass (cardiac magnetic resonance imaging). Skin sodium content, but not total body overhydration, correlated with systolic BP ( r =0.33, P =0.002). Moreover, skin sodium content correlated more strongly than total body overhydration did with left ventricular mass ( r =0.56, P skin sodium content is a strong explanatory variable for left ventricular mass, unaffected by BP and total body overhydration. In conclusion, we found skin sodium content to be closely linked to left ventricular mass in patients with CKD. Interventions that reduce skin sodium content might improve cardiovascular outcomes in these patients. Copyright © 2017 by the American Society of Nephrology.

Left ventricular diastolic dysfunction in chronic renal failure patients on chronic hemodialysis in Dr. Cipto-Mangunkusumo Hospital : the association with left ventricular mass

Directory of Open Access Journals (Sweden)

Idrus Alwi

2006-06-01

Full Text Available Fourty three patients with chronic renal failure undergoing chronic hemodialysis in Division of Nephrology and Hypertension, Faculty of Medicine, University of Indonesia/Cipto-Mangunkusumo Hospital, Jakarta, since October 2003 until February 2004, were examined for echocardiography (2-D, M-mode, Doppler imaging.Diastolic dysfunction was found in 58.1 % of chronic renal failure patients on hemodialysis. There was no significant difference between left ventricular mass in the group with or without left ventricular diastolic dysfunction. (Med J Indones 2006; 15:105-8Keywords: Left ventricular mass, diastolic function, chronic renal failure, hemodyalisis

Postexertional Supraventricular Tachycardia in Children with Catecholaminergic Polymorphic Ventricular Tachycardia

Directory of Open Access Journals (Sweden)

Scott D. N. Else

2012-01-01

Full Text Available Catecholaminergic polymorphic ventricular tachycardia (CPVT is a severe arrhythmia associated with sudden death in the young. It is caused by defective calcium handling in ventricular myocytes. The association of supraventricular tachycardia (SVT with CPVT is described in the literature, occurring in the lead-up to ventricular tachycardia during exercise testing. We describe three cases of SVT that were initiated in the recovery period of exercise testing in children with CPVT.

Late deterioration of left ventricular function after right ventricular pacemaker implantation.

Science.gov (United States)

Bellmann, Barbara; Muntean, Bogdan G; Lin, Tina; Gemein, Christopher; Schmitz, Kathrin; Schauerte, Patrick

2016-09-01

Right ventricular (RV) pacing induces a left bundle branch block pattern on ECG and may promote heart failure. Patients with dual chamber pacemakers (DCPs) who present with progressive reduction in left ventricular ejection fraction (LVEF) secondary to RV pacing are candidates for cardiac resynchronization therapy (CRT). This study analyzes whether upgrading DCP to CRT with the additional implantation of a left ventricular (LV) lead improves LV function in patients with reduced LVEF following DCP implantation. Twenty-two patients (13 males) implanted with DCPs and a high RV pacing percentage (>90%) were evaluated in term of new-onset heart failure symptoms. The patients were enrolled in this retrospective single-center study after obvious causes for a reduced LVEF were excluded with echocardiography and coronary angiography. In all patients, DCPs were then upgraded to biventricular devices. LVEF was analyzed with a two-sided t-test. QRS duration and brain natriuretic peptide (BNP) levels were analyzed with the unpaired t-test. LVEF declined after DCP implantation from 54±10% to 31±7%, and the mean QRS duration was 161±20 ms during RV pacing. NT-pro BNP levels were elevated (3365±11436 pmol/L). After upgrading to a biventricular device, a biventricular pacing percentage of 98.1±2% was achieved. QRS duration decreased to 108±16 ms and 106±20 ms after 1 and 6 months, respectively. There was a significant increase in LVEF to 38±8% and 41±11% and a decrease in NT-pro BNP levels to 3088±2326 pmol/L and 1860±1838 pmol/L at 1 and 6 months, respectively. Upgrading to CRT may be beneficial in patients with DCPs and heart failure induced by a high RV pacing percentage.

Flow-related Right Ventricular - Pulmonary Arterial Pressure Gradients during Exercise.

Science.gov (United States)

Wright, Stephen P; Opotowsky, Alexander R; Buchan, Tayler A; Esfandiari, Sam; Granton, John T; Goodman, Jack M; Mak, Susanna

2018-06-06

The assumption of equivalence between right ventricular and pulmonary arterial systolic pressure is fundamental to several assessments of right ventricular or pulmonary vascular hemodynamic function. Our aims were to 1) determine whether systolic pressure gradients develop across the right ventricular outflow tract in healthy adults during exercise, 2) examine the potential correlates of such gradients, and 3) consider the effect of such gradients on calculated indices of right ventricular function. Healthy untrained and endurance-trained adult volunteers were studied using right-heart catheterization at rest and during submaximal cycle ergometry. Right ventricular and pulmonary artery pressures were simultaneously transduced, and cardiac output was determined by thermodilution. Systolic pressures, peak and mean gradients, and indices of chamber, vascular, and valve function were analyzed offline. Summary data are reported as mean ± standard deviation or median [interquartile range]. No significant right ventricular outflow tract gradients were observed at rest (mean gradient = 4 [3-5] mmHg), and calculated effective orifice area was 3.6±1.0 cm2. Right ventricular systolic pressure increases during exercise were greater than that of pulmonary artery systolic pressure. Accordingly, mean gradients developed during light exercise (8 [7-9] mmHg) and increased during moderate exercise (12 [9-14] mmHg, p < 0.001). The magnitude of the mean gradient was linearly related to cardiac output (r2 = 0.70, p < 0.001). In healthy adults without pulmonic stenosis, systolic pressure gradients develop during exercise, and the magnitude is related to blood flow rate.

Ventricular distension and diastolic coronary blood flow in the anaesthetized dog.

Science.gov (United States)

Gattullo, D; Linden, R J; Losano, G; Pagliaro, P; Westerhof, N

1993-01-01

There appears to be no agreement as to whether or not an increase in diastolic left ventricular pressure and/or volume can cause a decrease in diastolic coronary blood flow. We investigated the problem in the anaesthetized dog using a flaccid freely distensible latex balloon inserted into the left ventricle with the animal on extracorporeal circulation and the coronary perfusion pressure constant at about 45 mm Hg. Maximal vasodilatation and suppression of autoregulation in coronary vasculature was obtained by the intracoronary infusion of dipyridamole (10-40 mg/h). Ventricular volume was changed in steps of 10 ml from 10 to 70 ml and back to 10 ml, whilst recording coronary blood flow and left ventricular pressure in the left circumflex coronary artery. Over a range of ventricular volumes from 20 to 50 ml and a concomitant rise in diastolic ventricular pressure to about 20 mm Hg there was no change in the diastolic coronary flow. Only when the ventricular volume was more than two times the control value (i.e. exceeded 50 ml) and left ventricular pressure was more than 20 mm Hg, was there a decrease in coronary flow. During the return of the volume to the control level there was a fall in diastolic flow and ventricular contractility with respect to the values obtained when the volume was increased; these two effects were transient lasting less than 10 min. It was not considered that any of the three models of the coronary circulation, waterfall, intramyocardial pump or varying elastance model could explain our results.(ABSTRACT TRUNCATED AT 250 WORDS)

Impact of Major Pulmonary Resections on Right Ventricular Function: Early Postoperative Changes.

Science.gov (United States)

Elrakhawy, Hany M; Alassal, Mohamed A; Shaalan, Ayman M; Awad, Ahmed A; Sayed, Sameh; Saffan, Mohammad M

2018-01-15

Right ventricular (RV) dysfunction after pulmonary resection in the early postoperative period is documented by reduced RV ejection fraction and increased RV end-diastolic volume index. Supraventricular arrhythmia, particularly atrial fibrillation, is common after pulmonary resection. RV assessment can be done by non-invasive methods and/or invasive approaches such as right cardiac catheterization. Incorporation of a rapid response thermistor to pulmonary artery catheter permits continuous measurements of cardiac output, right ventricular ejection fraction, and right ventricular end-diastolic volume. It can also be used for right atrial and right ventricular pacing, and for measuring right-sided pressures, including pulmonary capillary wedge pressure. This study included 178 patients who underwent major pulmonary resections, 36 who underwent pneumonectomy assigned as group (I) and 142 who underwent lobectomy assigned as group (II). The study was conducted at the cardiothoracic surgery department of Benha University hospital in Egypt; patients enrolled were operated on from February 2012 to February 2016. A rapid response thermistor pulmonary artery catheter was inserted via the right internal jugular vein. Preoperatively the following was recorded: central venous pressure, mean pulmonary artery pressure, pulmonary capillary wedge pressure, cardiac output, right ventricular ejection fraction and volumes. The same parameters were collected in fixed time intervals after 3 hours, 6 hours, 12 hours, 24 hours, and 48 hours postoperatively. For group (I): There were no statistically significant changes between the preoperative and postoperative records in the central venous pressure and mean arterial pressure; there were no statistically significant changes in the preoperative and 12, 24, and 48 hour postoperative records for cardiac index; 3 and 6 hours postoperative showed significant changes. There were statistically significant changes between the preoperative and

Obesity and exercise-induced ectopic ventricular arrhythmias in apparently healthy middle aged adults.

Science.gov (United States)

Sabbag, Avi; Sidi, Yechezkel; Kivity, Shaye; Beinart, Roy; Glikson, Michael; Segev, Shlomo; Goldenberg, Ilan; Maor, Elad

2016-03-01

Obesity and overweight are strongly associated with cardiovascular morbidity and mortality. However, there are limited data on the association between excess weight and the risk of ectopic ventricular activity. We investigated the association between body mass index (BMI) and the risk for ectopic ventricular activity (defined as multiple ventricular premature beats (≥3), ventricular bigeminy, nonsustained ventricular tachycardia or sustained ventricular tachycardia) during exercise stress testing among 22,516 apparently healthy men and women who attended periodic health screening examinations between the years 2000 and 2014. All subjects had completed maximal exercise stress testing annually according to the Bruce protocol. Subjects were divided at baseline into three groups: normal weight (BMI ≥ 18.5 kg/m(2) andexercise-induced ectopic ventricular activity arrhythmias was highest among obese subjects, intermediate among overweight subjects and lowest among subjects with normal weight (3.4%, 2.7% and 2.2% respectively; p exercise compared with subjects with normal weight (p = 0.005), and that each 1 kg/m(2) increase in BMI was associated with a significant 4% (p = 0.002) increased adjusted risk for exercise-induced ventricular arrhythmias. Obesity is independently associated with increased likelihood of ectopic ventricular arrhythmia during exercise. © The European Society of Cardiology 2015.

Ventricular Tachycardia in the Absence of Structural Heart Disease

Directory of Open Access Journals (Sweden)

Luis R. P. Scott

2005-04-01

Full Text Available In up to 10% of patients who present with ventricular tachycardia (VT, obvious structural heart disease is not identified. In such patients, causes of ventricular arrhythmia include right ventricular outflow tract (RVOT VT, extrasystoles, idiopathic left ventricular tachycardia (ILVT, idiopathic propranolol-sensitive VT (IPVT, catecholaminergic polymorphic VT (CPVT, Brugada syndrome, and long QT syndrome (LQTS. RVOT VT, ILVT, and IPVT are referred to as idiopathic VT and generally do not have a familial basis. RVOT VT and ILVT are monomorphic, whereas IPVT may be monomorphic or polymorphic. The idiopathic VTs are classified by the ventricle of origin, the response to pharmacologic agents, catecholamine dependence, and the specific morphologic features of the arrhythmia. CPVT, Brugada syndrome, and LQTS are inherited ion channelopathies. CPVT may present as bidirectional VT, polymorphic VT, or catecholaminergic ventricular fibrillation. Syncope and sudden death in Brugada syndrome are usually due to polymorphic VT. The characteristic arrhythmia of LQTS is torsades de pointes. Overall, patients with idiopathic VT have a better prognosis than do patients with ventricular arrhythmias and structural heart disease. Initial treatment approach is pharmacologic and radiofrequency ablation is curative in most patients. However, radiofrequency ablation is not useful in the management of inherited ion channelopathies. Prognosis for patients with VT secondary to ion channelopathies is variable. High-risk patients (recurrent syncope and sudden cardiac death survivors with inherited ion channelopathies benefit from implantable cardioverter-defibrillator placement. This paper reviews the mechanism, clinical presentation, and management of VT in the absence of structural heart disease.

Outcomes of patients with right ventricular failure on milrinone after left ventricular assist device implantation.

Science.gov (United States)

Tsiouris, Athanasios; Paone, Gaetano; Brewer, Robert J; Nemeh, Hassan W; Borgi, Jamil; Morgan, Jeffrey A

2015-01-01

Previous studies have grouped together both patients requiring right ventricular assist devices (RVADs) with patients requiring prolonged milrinone therapy after left ventricular assist device (LVAD) implantation. We retrospectively identified 149 patients receiving LVADs and 18 (12.1%) of which developed right ventricular (RV) failure. We then separated these patients into those requiring RVADs versus prolonged milrinone therapy. This included 10 patients who were treated with prolonged milrinone and eight patients who underwent RVAD placement. Overall, the RV failure group had worse survival compared with the non-RV failure cohort (p = 0.038). However, this was only for the subgroup of patients who required RVADs, who had a 1, 6, 12, and 24 month survival of 62.5%, 37.5%, 37.5%, and 37.5%, respectively, versus 96.8%, 92.1%, 86.7%, and 84.4% for patients without RV failure (p milrinone therapy for RV failure had similar survivals compared with patients without RV failure. In the RV failure group, age, preoperative renal failure, and previous cardiac surgery were predictors of the need for prolonged postoperative milrinone. As LVADs become a more widely used therapy for patients with refractory, end-stage heart failure, it will be important to reduce the incidence of RV failure, as it yields significant morbidity and increases cost.

Case report: paradoxical ventricular septal motion in the setting of primary right ventricular myocardial failure.

Science.gov (United States)

Maslow, Andrew; Schwartz, Carl; Mahmood, Feroze; Singh, Arun; Heerdt, Paul M

2009-07-01

In this report, a case of right ventricular (RV) failure, hemodynamic instability, and systemic organ failure is described to highlight how paradoxical ventricular systolic septal motion (PVSM), or a rightward systolic displacement of the interventricular septum, may contribute to RV ejection. Multiple inotropic medications and vasopressors were administered to treat right heart failure and systemic hypotension in a patient following combined aortic and mitral valve replacement. In the early postoperative period, echocardiographic evaluation revealed adequate left ventricular systolic function, akinesis of the RV myocardial tissues, and PVSM. In the presence of PVSM, RV fractional area of contraction was > or =35% despite akinesis of the primary RV myocardial walls. The PVSM appeared to contribute toward RV ejection. As a result, the need for multiple inotropes was re-evaluated, in considering that end-organ dysfunction was the result of systemic hypotension and prolonged vasopressor administration. After discontinuation of phosphodiesterase inhibitors, native vascular tone returned and the need for vasopressors declined. This was followed by recovery of systemic organ function. Echocardiographic re-evaluation two years later, revealed persistent akinesis of the RV myocardial tissues and PVSM, the latter appearing to contribute toward RV ejection. This case highlights the importance of left to RV interactions, and how PVSM may mediate these hemodynamic interactions.

Assessment of right ventricular systolic function by tissue Doppler echocardiography

DEFF Research Database (Denmark)

Kjærgaard, Jesper

2012-01-01

This thesis summarizes a series of studies performed in order to assess the clinical usefulness of a novel echocardiographic technology that allows non-invasive assessment of regional right ventricular myocardial velocities and deformation: tissue Doppler echocardiography. While the technology...... is a promising tool for improving our understanding of right ventricular hemodynamics, several aspects of the technology must be evaluated. The accuracy and reproducibility of the technology is evaluated in vitro, and normal values, impact of changes in loading of the right ventricle, response to exercise...... on right ventricular hemodynamics: pulmonary embolism, Arrhythmogenic right ventricular cardiomyopathy and pulmonary regurgitation, the latter in an animal model. The conclusions of the thesis are: Color tissue Doppler echocardiography accurately measures velocities, SR and strain in vitro. No systematic...

Predictors of the left ventricular dysfunction induced by ventricular arrhythmia

Directory of Open Access Journals (Sweden)

А. І. Vytryhovskiy

2016-08-01

Full Text Available The most powerful predictor of life-threatening arrhythmia risk is a combination of low heart rate variability with low ejection fraction (EF of the left ventricle. Aim. To identify predictors of left ventricle dysfunction which is induced by ventricular arrhythmia. Materials and methods. To diagnose structural changes of left ventricular functional capacity and reserves in patients with previous myocardial infarction and patients with high and very high cardiovascular risk by SCORE scale and for establishment the relationship between morphological heart changes and pathological phenomenon of heart turbulence echocardiography and study of heart rate turbulence variability were performed. 603 patients were selected for the research. All patients were divided into groups: group 1 – patients with coronary heart disease, but without associated risk factors, such as smoking, obesity, metabolic syndrome; group 2 – patients who smoke tobacco more than 2 years (very high cardiovascular risk by scale SCORE; group 3 – patients with metabolic syndrome without coronary heart disease or arterial hypertension (very high cardiovascular risk by scale SCORE. The control group consisted of 149 persons. Results. The feature of structural changes in patients with myocardial infarction and in patients with a high cardiovascular risk by SCORE with heart rate turbulence compared with cases without НRT is considerably thickening of the left interventricular septum in systole. Based on this, it can be argued that the emergence of ventricular arrhythmia and accordingly phenomenon of heart rate turbulence in patients with existing cardiovascular diseases and risk factors has both morphological and functional character. Significant difference of echocardioscopy parameters in patients with postinfarction cardiosclerosis and risk factors by the SCORE system was established by index of intraventricular septum thickness in systole, and in persons with high risk – in

Bayesian Classification Models for Premature Ventricular Contraction Detection on ECG Traces.

Science.gov (United States)

Casas, Manuel M; Avitia, Roberto L; Gonzalez-Navarro, Felix F; Cardenas-Haro, Jose A; Reyna, Marco A

2018-01-01

According to the American Heart Association, in its latest commission about Ventricular Arrhythmias and Sudden Death 2006, the epidemiology of the ventricular arrhythmias ranges from a series of risk descriptors and clinical markers that go from ventricular premature complexes and nonsustained ventricular tachycardia to sudden cardiac death due to ventricular tachycardia in patients with or without clinical history. The premature ventricular complexes (PVCs) are known to be associated with malignant ventricular arrhythmias and sudden cardiac death (SCD) cases. Detecting this kind of arrhythmia has been crucial in clinical applications. The electrocardiogram (ECG) is a clinical test used to measure the heart electrical activity for inferences and diagnosis. Analyzing large ECG traces from several thousands of beats has brought the necessity to develop mathematical models that can automatically make assumptions about the heart condition. In this work, 80 different features from 108,653 ECG classified beats of the gold-standard MIT-BIH database were extracted in order to classify the Normal, PVC, and other kind of ECG beats. Three well-known Bayesian classification algorithms were trained and tested using these extracted features. Experimental results show that the F1 scores for each class were above 0.95, giving almost the perfect value for the PVC class. This gave us a promising path in the development of automated mechanisms for the detection of PVC complexes.

Salbutamol Abuse is Associated with Ventricular Fibrillation

Directory of Open Access Journals (Sweden)

Emin UYSAL

2015-06-01

Full Text Available SUMMARY: Salbutamol-induced cardiac complications are well-established. Herein, we describe a case of a 24-year female who was admitted to the emergency department because of a suicide attempt with salbutamol (76 mg. Salbutamol abuse induced the development of supraventricular tachycardia and ventricular fibrillation. Regular sinus rhythm was restored with defibrillation. The hypokalemic patient who stayed in the intensive care unit was discharged after 48 hours of hospitalization. Key words: Salbutamol, suicide, ventricular fibrillation

Clustering Of Left Ventricular Wall Motion Patterns

Science.gov (United States)

Bjelogrlic, Z.; Jakopin, J.; Gyergyek, L.

1982-11-01

A method for detection of wall regions with similar motion was presented. A model based on local direction information was used to measure the left ventricular wall motion from cineangiographic sequence. Three time functions were used to define segmental motion patterns: distance of a ventricular contour segment from the mean contour, the velocity of a segment and its acceleration. Motion patterns were clustered by the UPGMA algorithm and by an algorithm based on K-nearest neighboor classification rule.

Ventricular tachycardia induced by weight loss pills

DEFF Research Database (Denmark)

Pareek, Manan; Hansson, Nils Henrik; Grove, Erik Lerkevang

2013-01-01

A previously healthy 29-year-old man was admitted with palpitations, dizziness, and near-syncope after he had recently started taking weight loss pills purchased on the internet. The pills contained caffeine and ephedrine. An electrocardiogram and telemetry revealed multiple episodes of non......-sustained monomorphic ventricular tachycardia, which was successfully treated with amiodarone. In conclusion, unauthorized weight loss pills can be harmful. In particular, ephedrine-containing drugs carry a risk of ventricular tachycardia and should be discouraged....

Studies of left ventricular volume estimation from single photon emission computed tomography

International Nuclear Information System (INIS)

Hiraki, Yoshio; Shimizu, Mitsuharu; Joja, Ikuo; Aono, Kaname; Yanagi, Hidekiyo; Indo, Haruaki; Seno, Yoshimasa; Teramoto, Shigeru; Nagaya, Isao.

1988-01-01

We studied the comparative accuracy of 99m Tc cardiac blood pool Single Photon Emission Computed Tomography (SPECT) for the measurement of left ventricular volume in 20 patients undergoing SPECT and single plane contrast left ventriculography (LVG). Left ventricular volume was calculated based on the total number of voxels in left ventricle. End-diastolic left ventricular volume (EDV) and end-systolic left ventricular volume (ESV) calculated from SPECT were compared with those from LVG. SPECT volume values showed a high degree of correlation with those by LVG (r = 0.923 for EDV, r = 0.903 for ESV). We appreciated the usefulness and accuracy of SPECT in measuring left ventricular volume because of its three-dimensional information. (author)

Correlation between right ventricular T1 mapping and right ventricular dysfunction in non-ischemic cardiomyopathy.

Science.gov (United States)

Jellis, Christine L; Yingchoncharoen, Teerapat; Gai, Neville; Kusunose, Kenya; Popović, Zoran B; Flamm, Scott; Kwon, Deborah

2018-01-01

Right ventricular (RV) fibrosis is increasingly recognized as the underlying pathological substrate in a variety of clinical conditions. We sought to employ cardiac magnetic resonance (CMR) techniques of strain imaging and longitudinal relaxation time (T 1 ) mapping to better examine the relationship between RV function and structure. Our aim was to initially evaluate the feasibility of these techniques to evaluate the right ventricle. We then sought to explore the relationship between RV function and underlying fibrosis, along with examining the evolution of RV remodeling according to the amount of baseline fibrosis. Echocardiography was performed in 102 subjects with non-ischemic cardiomyopathy. Right ventricular parameters were assessed including: fractional area change (FAC) and longitudinal strain. The same cohort underwent CMR. Post-contrast T 1 mapping was performed as a marker of fibrosis with a Look-Locker technique using inversion recovery imaging. Mid-ventricular post-contrast T 1 values of the RV free wall, RV septum and lateral LV were calculated using prototype analysis software. Biventricular volumetric data including ejection fraction was measured by CMR using a cine short axis stack. CMR strain analysis was also performed to assess 2D RV longitudinal and radial strain. Simultaneous biochemical and anthropometric data were recorded. Subjects were followed over a median time of 29 months (IQR 20-37 months) with echocardiography to evaluate temporal change in RV FAC according to baseline post-contrast T 1 values. Longitudinal data analysis was performed to adjust for patient loss during follow-up. Subjects (62% men, 51 ± 15 years) had mild to moderately impaired global RV systolic function (RVEF = 39 ± 15%; RVEDV = 187 ± 69 ml; RVESV = 119 ± 68 ml) and moderate left ventricular dysfunction at baseline (LVEF 30 ± 17%). Good correlation was observed between mean LV and RV post-contrast T 1 values (r = 0.652, p�

Paradox image: a noninvasive index of regional left-ventricular dyskinesis

International Nuclear Information System (INIS)

Holman, B.L.; Wynne, J.; Idoine, J.; Zielonka, J.; Neill, J.

1979-01-01

The paradox image, a functional image of regional dyskinesis derived from the equilibrium (gated) radionuclide ventriculogram, was constructed by subtracting the background-corrected end-diastolic frame from the background-corrected end-systolic frame. In 11 patients showing dyskinesis by contrast ventriculography, the percentage of left-ventricular picture elements containing paradox ranged from 3.6 to 55.6% (21.44% +- 4.45 s.e.m.). In 11 patients with normokinesis and in eight patients with hypookinesis by contrast ventriculography, the left-ventricular picture elements demonstrating paradox were less than 1.1% in all cases. In nine patients with akinesis, the percentage of left-ventricular picture elements containing paradox was 2.05% +- 0.96 s.e.m. and was less than 2% in seven patients. There was also an excellent agreement between the location of dyskinesis on the paradox image and that by contrast ventriculography. The paradox image is a sensitive indicator of left-ventricular dyskinesis and should be useful in the evaluation of patients with suspected left-ventricular asynergy

Hollow mandrin facilitates external ventricular drainage placement.

Science.gov (United States)

Heese, O; Regelsberger, J; Kehler, U; Westphal, M

2005-07-01

Placement of ventricular catheters is a routine procedure in neurosurgery. Ventricle puncture is done using a flexible ventricular catheter stabilised by a solid steel mandrin in order to improve stability during brain penetration. A correct catheter placement is confirmed after removing the solid steel mandrin by observation of cerebrospinal fluid (CSF) flow out of the flexible catheter. Incorrect placement makes further punctures necessary. The newly developed device allows CSF flow observation during the puncture procedure and in addition precise intracranial pressure (ICP) measurement. The developed mandrin is hollow with a blunt tip. On one side 4-5 small holes with a diameter of 0.8 mm are drilled corresponding exactly with the holes in the ventricular catheter, allowing CSF to pass into the hollow mandrin as soon as the ventricle is reached. By connecting a small translucent tube at the distal portion of the hollow mandrin ICP can be measured without loss of CSF. The system has been used in 15 patients with subarachnoid haemorrhage (SAH) or intraventricular haemeorrhage (IVH) and subsequent hydrocephalus. The new system improved the external ventricular drainage implantation procedure. In all 15 patients catheter placement was correct. ICP measurement was easy to perform immediately at ventricle puncture. In 4 patients at puncture no spontaneous CSF flow was observed, therefore by connecting a syringe and gentle aspiration of CSF correct placement was confirmed in this unexpected low pressure hydrocephalus. Otherwise by using the conventional technique further punctures would have been necessary. Advantages of the new technique are less puncture procedures with a lower risk of damage to neural structures and reduced risk of intracranial haemorrhages. Implantation of the ventricular catheter to far into the brain can be monitored and this complication can be overcome. Using the connected pressure monitoring tube an exact measurement of the opening

Catecholaminergic polymorphic ventricular tachycardia in 2012

Directory of Open Access Journals (Sweden)

Christian van der Werf

2011-12-01

Full Text Available Catecholaminergic polymorphic ventricular tachycardia (CPVT is a rare, potentially lethal inherited arrhythmia syndrome characterized by stress or emotion-induced ventricular arrhythmias. CPVT was first described in 1960, while the genetic basis underlying this syndrome was discovered in 2001. The past decade has seen substantial advances in understanding the pathophysiology of CPVT. In addition, significant advances have been made in elucidating clinical characteristics of CPVT patients and new treatment options have become available. Here, we review current literature on CPVT to present state-of-the-art knowledge on the subject of the genetic basis, pathophysiology, clinical presentation, diagnosis, treatment and prognosis.

Arterial Ventricular Uncoupling with Age and Disease and Recoupling with Exercise

Science.gov (United States)

Chantler, Paul D

2017-01-01

The deterioration in arterial and cardiac function with aging impairs arterial ventricular coupling, an important determinant of cardiovascular performance. However, exercise training improves arterial ventricular coupling especially during exercise during the age and disease process. This review examines the concept of arterial-ventricular coupling, and how age, and disease uncouples but exercise training recouples the heart and arterial system. PMID:28072585

Evaluation of left ventricular function by nuclear stethoscope

International Nuclear Information System (INIS)

Nishimura, Tsunehiko

1981-01-01

The Nuclear Stethoscope (N.S.) is a unique cardiac probe system that provides a precise, rapid, noninvasive method to directly quantify ventricular functions at the bedside or actual beat-to-beat or composite beat basis. The accuracy and validity of N.S. were studied in 42 patients with cardiac diseases in comparison with camera-computer EF. The N.S. EF was well correlated with camera-computer EF (r = 0.82). In this study, clinical application of N.S. was as follows. 1. Beat-to-beat left ventricular volume response for evaluation of arrythmia (atrial fibrillation, premature ventricular conduction, bigemy et al.) 2. exercise study by handgrip and ergometer. EF is an extremely sensitive indicator to discriminate coronary arteries diseases from normal subjects. (author)

Evaluation of left ventricular function by nuclear stethoscope

Energy Technology Data Exchange (ETDEWEB)

Nishimura, T [National Cardiovascular Center, Suita, Osaka (Japan)

1981-03-01

The Nuclear Stethoscope (N.S.) is a unique cardiac probe system that provides a precise, rapid, noninvasive method to directly quantify ventricular functions at the bedside or actual beat-to-beat or composite beat basis. The accuracy and validity of N.S. were studied in 42 patients with cardiac diseases in comparison with camera-computer EF. The N.S. EF was well correlated with camera-computer EF (r = 0.82). In this study, clinical application of N.S. was as follows. 1. Beat-to-beat left ventricular volume response for evaluation of arrythmia (atrial fibrillation, premature ventricular conduction, bigemy et al.) 2. exercise study by handgrip and ergometer. EF is an extremely sensitive indicator to discriminate coronary arteries diseases from normal subjects.

Assessment of cardiac performance with quantitative radionuclide angiocardiography: sequential left ventricular ejection fraction, normalized left ventricular ejection rate, and regional wall motion

International Nuclear Information System (INIS)

Marshall, R.C.; Berger, H.J.; Costin, J.C.; Freedman, G.S.; Wolberg, J.; Cohen, L.S.; Gotischalk, A.; Zaret, B.L.

1977-01-01

Sequential quantitative first pass radionuclide angiocardiograms (RA) were used to measure left ventricular ejection fraction (LVEF) and left ventricular ejection rate (LVER), and to assess regional wall motion (RWM) in the anterior (ANT) and left anterior oblique (LAO) positions. Studies were obtained with a computerized multicrystal scintillation camera suitable for acquiring high count-rate data. Background was determined in a new fashion by selecting frames temporally from the left ventricular region of interest time-activity curve. A ''representative'' cardiac cycle was formed by summing together counts over three to six cardiac cycles. From this background corrected, high count-rate ''representative''cardiac cycle, LVEF, LVER, and RWM were determined. In 22 patients with normal sinus rhythm in the absence of significant valvular regurgitation, RA LVEF correlated well with that measured by contrast angiography (r = 0.95). LVER correlated well with LVEF measured at contrast angiography (r = 0.90) and allowed complete separation of those with normal (LVER = 3.4 +- 0.17 sec -1 ) and abnormal (LVER = 1.22 +- 0.11 sec -1 ) (P < 0.001) left ventricular performance. This separation was independent of background. Isoproterenol infusion in five normal subjects caused LVER to increase by 81 +- 17% while LVEF increased by 10 +- 2.0%. RWM was correctly defined in 21/22 patients and 89% of left ventricular segments with abnormal wall motion

In-core program for on line measurements of neutron, photon and nuclear heating parameters inside Jules Horowitz MTR reactor

International Nuclear Information System (INIS)

Lyoussi, A.; Reynard-Carette, C.

2014-01-01

Accurate on-line measurements of key parameters inside experimental channels of Material Testing Reactor are necessary to dimension the irradiation devices and consequently to conduct smart experiments on fuels and materials under suitable conditions. In particular the quantification of nuclear heating, a relevant parameter to reach adapted thermal conditions, has to be improved. These works focus on an important collaborative program between CEA and Aix-Marseille University called INCORE (Instrumentation for Nuclear radiations and Calorimetry On-line in Reactor) dedicated to the development of a new measurement methodology to quantify both nuclear heating and accurate radiation flux levels (neutrons and photons). The methodology, which is based on experiments carried out under irradiation conditions with a multi-sensor device (ionization chamber, fission chamber, gamma thermometer, calorimeter, SPND, SPGD) as well as works performed out-of nuclear/radiative environment on a reference sensor used to measure nuclear heating (calorimeter), is presented (authors)

Right ventricular systolic and diastolic function at rest in patients with coronary artery disease

International Nuclear Information System (INIS)

Caglar, N.M.; Araki, Haruo; Taira, Yuji; Fukuyama, Takaya; Nakamura, Motoomi

1985-01-01

Right ventricular systolic and diastolic function was studied in patients with ischemic heart disease using equilibrium radionuclide ventriculography. In patients with inferior myocardial infarction and proximal right coronary lesions, the right ventricular ejection fraction (0.43+-0.06, n=10, mean+-SD) and peak filling rate (1.7+-0.4 EDV/sec) were lower than normals (0.57+-0.07 and 2.7+-0.4 EDV/sec, n=10, p<0.001, respectively). In these patients, the right ventricular time to peak filling rate was longer than in normals (225+-36 msec vs 136+-45 msec, p<0.001), while the left ventricular ejection fraction remained normal. In patients with inferior myocardial infarction and distal right coronary lesions, the right ventricular ejection fraction, peak filling rate and time to peak filling rate were not different from those in normals. Even in patients with proximal right coronary lesions, the right ventricular ejection fraction was normal unless they had an inferior myocardial infarction. A decreased left ventricular ejection fraction and abnormal motion of the ventricular septum did not affect the right ventricular ejection fraction. The present results suggest that patients with an inferior myocardial infarction and proximal right coronary lesion often develop right ventricular systolic and diastolic dysfunction. (author)

Right ventricular function during acute exacerbation of severe equine asthma.

Science.gov (United States)

Decloedt, A; Borowicz, H; Slowikowska, M; Chiers, K; van Loon, G; Niedzwiedz, A

2017-09-01

Pulmonary hypertension has been described in horses with severe equine asthma, but its effect on the right ventricle has not been fully elucidated. To evaluate right ventricular structure and function after a 1-week period of pulmonary hypertension secondary to acute exacerbation of severe equine asthma. Prospective study. A clinical episode of severe equine asthma was induced experimentally in six susceptible horses. Examinations in remission and on day 7 of the clinical episode included a physical examination with clinical scoring, echocardiography, arterial blood gas measurements, venous blood sampling for cardiac biomarkers, intracardiac pressure measurements, right ventricular and right atrial myocardial biopsies, airway endoscopy and bronchoalveolar lavage. After 1 month of recovery, physical examination, echocardiography and cardiac biomarker analysis were repeated. Echocardiographic and pressure measurements were compared with those in 10 healthy control horses. All horses developed clinical signs of acute pulmonary obstruction. Right heart pressures increased significantly. Altered right ventricular function could be detected by tissue Doppler and speckle tracking echocardiography. Cardiac troponin concentrations did not increase significantly, but were highly elevated in one horse which exercised in the paddock prior to sampling. Focal neutrophil infiltration was present in two myocardial samples. Even in remission, asthmatic horses showed a thicker right ventricular wall, an increased left ventricular end-systolic eccentricity index at chordal level and decreased right ventricular longitudinal strain compared with controls. The induced clinical episode was rather mild and the number of horses was limited because of the invasive nature of the study. Pulmonary obstruction in asthmatic horses induces pulmonary hypertension with right ventricular structural and functional changes. © 2017 EVJ Ltd.

Discrete potentials guided radiofrequency ablation for idiopathic outflow tract ventricular arrhythmias.

Science.gov (United States)

Liu, Enzhao; Xu, Gang; Liu, Tong; Ye, Lan; Zhang, Qitong; Zhao, Yanshu; Li, Guangping

2015-03-01

Discrete potentials (DPs) have been recorded and targeted as the site of ablation of the outflow tract arrhythmias. The aim of the present study was to investigate the significance of DPs with respect to mapping and ablation for idiopathic outflow tract premature ventricular contractions (PVCs) or ventricular tachycardias (VTs). Seventeen consecutive patients with idiopathic right or left ventricular outflow tract PVCs/VTs who underwent radiofrequency catheter ablation were included. Intracardiac electrograms during the mapping and ablation were analysed. During sinus rhythm, sharp high-frequency DPs that displayed double or multiple components were recorded following or buried in the local ventricular electrograms in all of the 17 patients, peak amplitude 0.51 ± 0.21 mV. The same potential was recorded prior to the local ventricular potential of the PVCs/VTs. Spontaneous reversal of the relationship of the DPs to the local ventricular electrogram during the arrhythmias was noted. The DPs were related to a region of low voltage showed by intracardiac high-density contact mapping. At the sites with DPs, lower unipolar and bipolar ventricular voltage of sinus beats were noted compared with the adjacent regions without DPs (unipolar: 6.1 ± 1.8 vs. 8.3 ± 2.3 mV, P Discrete potentials were not present in seven controls. Discrete potentials and related low-voltage regions were common in idiopathic outflow tract ventricular arrhythmias. Discrete potential- and substrate-guided ablation strategy will help to reduce the recurrence of idiopathic outflow tract arrhythmias. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

Longitudinal strain predicts left ventricular mass regression after aortic valve replacement for severe aortic stenosis and preserved left ventricular function.

Science.gov (United States)

Gelsomino, Sandro; Lucà, Fabiana; Parise, Orlando; Lorusso, Roberto; Rao, Carmelo Massimiliano; Vizzardi, Enrico; Gensini, Gian Franco; Maessen, Jos G

2013-11-01

We explored the influence of global longitudinal strain (GLS) measured with two-dimensional speckle-tracking echocardiography on left ventricular mass regression (LVMR) in patients with pure aortic stenosis (AS) and normal left ventricular function undergoing aortic valve replacement (AVR). The study population included 83 patients with severe AS (aortic valve area regression (all P regression in patients with pure AS undergoing AVR. Our findings must be confirmed by further larger studies.

Right ventricular function after acute myocardial infarction: dependence upon infarct related coronary artery

International Nuclear Information System (INIS)

Cho, Ihn Ho; Chun, Kyung A; Won, Kyu Chang; Lee, Hyung Woo; Hong, Geu Ru; Park, Jong Seon; Shin, Dong Gu; Kim, Young Jo; Shim, Bong Sub

2004-01-01

We studied to know the relation between right ventricular function and infarct-related artery after acute myocardial infarction. The right and left ventricular function after a first myocardial infarction was assessed ECG-gated blood pool single photon emission computed tomography (GBPS) algorithms (Cedars-Sinai Medical Center, Los Angels, Calif) (12 after LAD related infarction (group 1) and 15 after RCA related infarction (group 2)). The left ventricular ejection fraction, end-diastolic volume and end-systolic volume did not differ significantly between two groups( group 1 vs 2 :LVEF 50.8% vs 55.1%. LVEDV=73.2 vs 79.7 ml, LVESV=38 vs 44 ml : P>0.05), but right ventricular ejection fraction, end-diastolic volume and end-systolic volume were significantly different after anterior myocardial infarction between two groups( group 1 vs 2 : RVEF=57.3% vs 46.3%. RVEDV=56.4 vs 95.1 ml, RVESV=25.6 vs 54.6ml : P<0.05). There was evidence of right ventricular dilatation in the group with RCA related infarction. Six with inferior infarction had abnormal right ventricular ejection fractions (< 40%). The relation between right and left ventricular ejection fractions was markedly different in the two groups. In the group with RCA related infarction there was a significant linear relation between right and left ventricular ejection fraction(R=0.5). Whereas in the group with LAD related infarction there was not (R=-0.3). Thus right ventricular dysfunction commonly occurs after RCA related infarction. Right ventricular impairment is related after RCA related infarction, but are independent after LAD related infarction. Finally, the different effects of LAD and RCA related infarction on right ventricular function may be explained by site of the myocardial wall involvement after infarction

Right ventricular function in asthmatic children determined with PW-TDI

International Nuclear Information System (INIS)

Wang Shaona; Song Lili; Cong Lin; Li Liping; Huang Yanxia

2007-01-01

Objective: To assess the right ventricular function of asthmatic children in onset period or remission period by using PW-TDI. Method: 36 children with confirmed asthma were enrolled. In tricuspid annular, the ECHO were recorded with PW-PDI pattern to obtain fight ventricular function (Sm, e-peak, Vmax for a-peak, and e/a), ICT, ET, IRT and Tei-Index. These were carried out in acute attack period and stable period. Result: Right ventficular function parameter (Sm, Vmax for e-peak, Vmax for a-peak, e/a and Tei-Index) in acute attack period were significant different compared to those in stable period (P<0.05). Conclusions: The fight ventricular function was impaired in patients with asthma in acute attack period. PW-TDI is helpful for assessing right ventricular function to asthmatic children. (authors)

Eisenmenger ventricular septal defect in a Humboldt penguin (Spheniscus humboldti).

Science.gov (United States)

Laughlin, D S; Ialeggio, D M; Trupkiewicz, J G; Sleeper, M M

2016-09-01

The Eisenmenger ventricular septal defect is an uncommon type of ventricular septal defect characterised in humans by a traditionally perimembranous ventricular septal defect, anterior deviation (cranioventral deviation in small animal patients) of the muscular outlet septum causing malalignment relative to the remainder of the muscular septum, and overriding of the aortic valve. This anomaly is reported infrequently in human patients and was identified in a 45-day-old Humboldt Penguin, Spheniscus humboldti, with signs of poor growth and a cardiac murmur. This case report describes the findings in this penguin and summarises the anatomy and classification of this cardiac anomaly. To the authors' knowledge this is the first report of an Eisenmenger ventricular septal defect in a veterinary patient. Copyright © 2016 Elsevier B.V. All rights reserved.

Intraoperative Transesophageal Echocardiography and Right Ventricular Failure After Left Ventricular Assist Device Implantation.

Science.gov (United States)

Silverton, Natalie A; Patel, Ravi; Zimmerman, Josh; Ma, Jianing; Stoddard, Greg; Selzman, Craig; Morrissey, Candice K

2018-02-15

To determine whether intraoperative measures of right ventricular (RV) function using transesophageal echocardiography are associated with subsequent RV failure after left ventricular assist device (LVAD) implantation. Retrospective, nonrandomized, observational study. Single tertiary-level, university-affiliated hospital. The study comprised 100 patients with systolic heart failure undergoing elective LVAD implantation. Transesophageal echocardiographic images before and after cardiopulmonary bypass were analyzed to quantify RV function using tricuspid annular plane systolic excursion (TAPSE), tricuspid annular systolic velocity (S'), fractional area change (FAC), RV global longitudinal strain, and RV free wall strain. A chart review was performed to determine which patients subsequently developed RV failure (right ventricular assist device placement or prolonged inotrope requirement ≥14 days). Nineteen patients (19%) subsequently developed RV failure. Postbypass FAC was the only measure of RV function that distinguished between the RV failure and non-RV failure groups (21.2% v 26.5%; p = 0.04). The sensitivity, specificity, and area under the curve of an abnormal RV FAC (failure after LVAD implantation were 84%, 20%, and 0.52, respectively. No other intraoperative measure of RV function was associated with subsequent RV failure. RV failure increased ventilator time, intensive care unit and hospital length of stay, and mortality. Intraoperative measures of RV function such as tricuspid annular plane systolic excursion, tricuspid annular systolic velocity, and RV strain were not associated with RV failure after LVAD implantation. Decreased postbypass FAC was significantly associated with RV failure but showed poor discrimination. Copyright © 2018 Elsevier Inc. All rights reserved.

Cerebrovascular accidents in patients with a ventricular assist device.

Science.gov (United States)

Tsukui, Hiroyuki; Abla, Adib; Teuteberg, Jeffrey J; McNamara, Dennis M; Mathier, Michael A; Cadaret, Linda M; Kormos, Robert L

2007-07-01

A cerebrovascular accident is a devastating adverse event in a patient with a ventricular assist device. The goal was to clarify the risk factors for cerebrovascular accident. Prospectively collected data, including medical history, ventricular assist device type, white blood cell count, thrombelastogram, and infection, were reviewed retrospectively in 124 patients. Thirty-one patients (25%) had 48 cerebrovascular accidents. The mean ventricular assist device support period was 228 and 89 days in patients with and without cerebrovascular accidents, respectively (P cerebrovascular accidents occurred within 4 months after implantation. Actuarial freedom from cerebrovascular accident at 6 months was 75%, 64%, 63%, and 33% with the HeartMate device (Thoratec Corp, Pleasanton, Calif), Thoratec biventricular ventricular assist device (Thoratec Corp), Thoratec left ventricular assist device (Thoratec), and Novacor device (WorldHeart, Oakland, Calif), respectively. Twenty cerebrovascular accidents (42%) occurred in patients with infections. The mean white blood cell count at the cerebrovascular accident was greater than the normal range in patients with infection (12,900/mm3) and without infection (9500/mm3). The mean maximum amplitude of the thrombelastogram in the presence of infection (63.6 mm) was higher than that in the absence of infection (60.7 mm) (P = .0309). The risk of cerebrovascular accident increases with a longer ventricular assist device support period. Infection may activate platelet function and predispose the patient to a cerebrovascular accident. An elevation of the white blood cell count may also exacerbate the risk of cerebrovascular accident even in patients without infection. Selection of device type, prevention of infection, and meticulous control of anticoagulation are key to preventing cerebrovascular accident.

Left ventricular hypertrophy: virtuous intentions, malign consequences.

Science.gov (United States)

Pokharel, Saraswati; Sharma, Umesh C; Pinto, Yigal M

2003-06-01

Left ventricular hypertrophy (LVH) is currently the focus of intense cardiovascular research, with the resultant rapid evolution of novel concepts relating to its exceedingly complex pathophysiology. In addition to the alterations in signal transduction and disturbances in Ca(2+) homeostasis, there are structural changes in myofilaments, disorganization of the cytoskeletal framework and increased collagen synthesis. LVH is associated with progressive left ventricular remodeling that culminates to heart failure. The modern treatment of left ventricular hypertrophy is now largely based on the hypothesis that neuroendocrine activation is important in the progression of the disease and inhibition of neurohormones is likely to have long-term benefit with regard to morbidity and mortality. Drugs specifically designed to unload the left ventricle, such as diuretics and vasodilators, appears to be less effective in reducing LV mass and improving prognosis. Thus, the evolution of treatment for LVH itself has provided much enlightenment for our understanding of the fundamental biology of the disorder.

"Rescue" ablation of electrical storm in arrhythmogenic right ventricular cardiomyopathy in pregnancy.

Science.gov (United States)

Stec, Sebastian; Krynski, Tomasz; Baran, Jakub; Kulakowski, Piotr

2013-08-13

Radiofrequency ablation (RFCA) became a treatment of choice in patients with recurrent ventricular tachycardia, ventricular fibrillation, and appropriate interventions of implanted cardioverter-defibrillator (ICD), however, electrical storm (ES) ablation in a pregnant woman has not yet been reported. We describe a case of a successful rescue ablation of recurrent ES in a 26-year-old Caucasian woman during her first pregnancy (23rd week). The arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) was diagnosed 3 years earlier and several drugs as well as 2 ablations failed to control recurrences of ventricular tachycardia. RFCA was performed on the day of the third electric storm. The use of electroanatomic mapping allowed very low X-ray exposure, and after applications in the right ventricular outflow tract, arrhythmia disappeared. Three months after ablation, a healthy girl was delivered without any complications. During twelve-month follow-up there was no recurrence of ventricular tachycardia or ICD interventions. This case documents the first successful RFCA during ES due to recurrent unstable ventricular arrhythmias in a patient with ARVD/C in pregnancy. Current guidelines recommend metoprolol, sotalol and intravenous amiodarone for prevention of recurrent ventricular tachycardia in pregnancy, however, RFCA should be considered as a therapeutic option in selected cases. The use of 3D navigating system and near zero X-ray approach is associated with minimal radiation exposure for mother and fetus as well as low risk of procedural complication.

Normal left ventricular function does not protect against propafenone ...

African Journals Online (AJOL)

Normal left ventricular function does not protect against propafenone-induced incessant ventricular tachycardia. R. N. Scott Millar, J. B. Lawrenson, D.A. Milne. Abstract. Propafenone is a class Ic anti-arrhythmic agent with mild B-blocking properties which has recently become available in South Africa. We have used the ...

Flecainide Therapy Reduces Exercise-Induced Ventricular Arrhythmias in Patients With Catecholaminergic Polymorphic Ventricular Tachycardia

NARCIS (Netherlands)

van der Werf, Christian; Kannankeril, Prince J.; Sacher, Frederic; Krahn, Andrew D.; Viskin, Sami; Leenhardt, Antoine; Shimizu, Wataru; Sumitomo, Naokata; Fish, Frank A.; Bhuiyan, Zahurul A.; Willems, Albert R.; van der Veen, Maurits J.; Watanabe, Hiroshi; Laborderie, Julien; Haïssaguerre, Michel; Knollmann, Björn C.; Wilde, Arthur A. M.

2011-01-01

Objectives This study evaluated the efficacy and safety of flecainide in addition to conventional drug therapy in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT). Background CPVT is an inherited arrhythmia syndrome caused by gene mutations that destabilize cardiac

Usefulness of tomographic phase image in ventricular conduction abnormalities

International Nuclear Information System (INIS)

Sakurai, Mitsuru; Watanabe, Yoshihiko; Kondo, Takeshi

1985-01-01

In order to evaluate three-dimensional phase changes in ventricular conduction abnormalities, tomographic phase images were constructed in 7 normal subjects, 12 patients with ventricular pacing, 21 patients with bundle branch block and 12 patients with Wolff-Parkinson-White syndrome. Eight to 12 slices of the short-axis ventricular tomographic phase image (TPI) were derived using a 7-pinhole collimator, and compared with planar phase images (PPIs) in left anterior oblique (LAO) and right anterior oblique (RAO) projections. TPIs were excellent for observing biventricular phase changes in the long-axis direction. In 6 cases of complete right bundle branch block with left axis deviation (beyond -30 0 ), the phase delay in the left ventricular anterior wall was recognized in 5 cases by TPI, although it was difficult to be detected by PPIs. The site of the pacing electrode was identified by TPI in 11 out of 12 cases, compared to 8 cases by PPIs in LAO and RAO projections. The site of the accessory pathway in Wolff-Parkinson-White syndrome was detected in the basal slice of TPIs in 10 out of 12 cases, compared to 8 cases by PPI in the LAO projection. Therefore, it is obvious that TPIs offer more valid information than PPIs. In conclusion, TPI is useful for investigation of ventricular conduction abnormalities. (author)

Left ventricular performance during psychological stress

International Nuclear Information System (INIS)

Young, D.Z.; Massachusetts General Hospital, Boston; Dimsdale, J.E.; Moore, R.H.; Barlai-Kovach, M.; Newell, J.B.; McKusick, K.A.; Boucher, C.A.; Fifer, M.A.; Strauss, H.W.

1989-01-01

Left ventricular ejection fraction, systolic blood pressure and plasma norepinephrine were measured in six normotensive and six mildly hypertensive subjects during rest and psychological stress. Compared with rest, 8 of the 12 subjects developed significant changes in ejection fraction (increase in 6, decrease in 2); 10 of 12 subjects developed significant elevations of plasma norepinephrine; and all developed significant increases in systolic blood pressure. When the stress effects were examined for the total group, as opposed to within subjects, there were significant increases in plasma norepinephrine and systolic blood pressure but, interestingly, mean ejection fraction and stroke volume remained unchanged, implying stress led to increased left ventricular contractility. (orig.)

Intermittent′ restrictive ventricular septal defect in Tetralogy of Fallot

Directory of Open Access Journals (Sweden)

Sudhir S Shetkar

2015-01-01

Full Text Available Ventricular septal defect (VSD in Tetralogy of Fallot (TOF is usually large and non-restrictive with equalization of right and left ventricular pressures. Restrictive VSD in TOF is rare. We present an unusual case of TOF with restriction to VSD caused by accessory tricuspid valve tissue that varied with respiration.

Cardiomiopatia de takotsubo como causa de disfunção ventricular transitória Takotsubo cardiomyopathy causing transitory ventricular dysfunction

Directory of Open Access Journals (Sweden)

Angele A. Alves

2008-03-01

Full Text Available Relato do caso de mulher de 74 anos, com hipertensão arterial sistêmica e insuficiência vascular periférica, que apresentou sintomas de síndrome coronariana aguda. A angiografia coronariana demonstrou artérias sem obstruções significativas. A ventriculografia e a ecocardiografia demonstraram acinesia dos segmentos médios e apicais, e hipercinesia dos segmentos basais do ventrículo esquerdo. A paciente evoluiu com recuperação completa da função global e motilidade segmentar em ecocardiografia realizada duas semanas após o início dos sintomas. Esse padrão incomum e reversível de disfunção sistólica e comprometimento segmentar dando ao ventrículo esquerdo forma semelhante a um takotsubo é hoje conhecido como cardiomiopatia do estresse.This is the report of a 74-year-old female patient with a history of systemic hypertension and peripheral vascular disease who presented acute coronary syndrome symptoms. Coronary angiography showed coronary arteries with no significant obstructions. Ventriculography and echocardiography showed akinesia in mid and apical segments; and hyperkinesia of left ventricle basal segments. Two weeks after the onset of symptoms, a new echocardiogram demonstrated normal global and regional systolic function. The uncommon, reversible pattern for systolic dysfunction and segmental compromising that gives left ventricle a takostubo-like shape is known today as stress cardiomyopathy.

Review of some problems encountered with In-Core Fission chambers and Self-Powered Neutron Detectors in PWR's. Tests - Present use - Outlook on the near future

International Nuclear Information System (INIS)

Duchene, Jean; Verdant, Robert.

1979-01-01

The working conditions of in-core detectors are investigated as well as some reliability problems which depend on nuclear environment (such as decrease of sensibility, loss of insulation...). Then we review the long-term irradiation tests in experimental reactor that have been carried out by the CEA these last years, with fission chambers (FC) and Self-Powered Detectors (SPD). The travelling probe system with moveable FC used in the 900 MWe PWR is briefly described. Finally an outlook on future possibilities is given; for instance the use of fixed SPD and a moveable FC in the same thimble, allowing recalibration of the fixed detectors [fr

EXERCISE-INDUCED VENTRICULAR-TACHYCARDIA - A RARE MANIFESTATION OF DIGITALIS TOXICITY

NARCIS (Netherlands)

GOSSELINK, ATM; CRIJNS, HJGM; WIESFELD, ACP; LIE, KI

Digitalis intoxication is one of the most common adverse drug reactions. Although some arrhythmias are seen more frequently than others, virtually any rhythm disturbance, including ventricular tachycardia, may occur. However, to our knowledge, exercise-induced ventricular tachycardia as a

Preliminary study of left ventricular cavity-to-myocardial count ratio. A new parameter for left ventricular function

International Nuclear Information System (INIS)

Zhou Ying; Qu Wanying; Zhu Ming; Gao Wenping; Zhao Hongshan

1995-01-01

A new simple quantitative parameter, left ventricular cavity-to-myocardial count ratio (C/M ratio) was suggested and compared with LVEF to assess its reliability and clinical value. Of 220 patients in the study, 102 had both exercise 99m Tc-MIBI myocardial SPECT imaging and resting radionuclide ventriculography, another 118 patients had both rest 99m Tc-MIBI myocardial SPECT imaging and rest radionuclide ventriculography, 740 MBq of 99m Tc-MIBI was injected intravenously. Both the exercise and rest C/M ratio were determined on short-axis tomograms and LVEF were calculated from radionuclide ventriculography. The correlation between LVEF and the C/M (exercise and rest) was analyzed. There was a positive linear correlation between LVEF measured by ventriculography and both C/M exercise ratio (r = 0.6964) and C/M rest ratio (r = 0.6995). The sensitivity of C/M exercise and rest ratio for detecting patients with left ventricular dysfunction is 71.9%, 68.6%; the specificity is 92.9%, 97.0%; the accuracy is 86.3%, 84.7% respectively. C/M ratio can accurately identify patients with CAD who have resting left ventricular dysfunction. It was highly reproducible, reliable and useful in clinical diagnosis

Angiographic differentiation of type of ventricular septal defects

International Nuclear Information System (INIS)

Cheon, Mal Soon; Park, Hee Young; Kim, Yang Sook

1989-01-01

Defects of the ventricular septum are the commonest type of congenital cardiac malformations. A classification with axial angiography of the subtypes of ventricular septal defects is proposed on the study of 126 patients with defects of the ventricular septum. The results were as follows: 1. The incidence of the ventricular septal defects was 39.6% of congenital heart malformation. 2. The sex distribution of cases were 70 males and 56 females, the age ranged from 13 months to 26 years. 3. Angiographic features seen by axial angiography were as follows: a. Perimembranous defects as seen on long axial view of left ventriculogram were in continuity wity aortic valve. The relation of the defect to the tricuspid valve allows distinction of the extension of the preimembranous defect toward inlet, trabecular, or infundibular zones. This relation was determined angiographically, using the course of the contrast medium from the left ventricle through the ventricular septal defect, opacifying the right ventricle. In inlet excavation, the shunted blood opacified the recess between septal leaflet of tricuspid valve and interventricular septum in early phase, in infundibular excavation, opacified the recess between anterior leaflet of tricuspid valve and anterior free wall of right ventricle and in trabecular excavation, the shunted blood traversed anterior portion of tricuspid valve ring, opacified trabecular portion of right ventricle. b. Muscular defects were separated from the semilunar and atrioventricular valves. c, Subarterial defects were related to both semilunar valves, and they were best demonstrated on the elongated right anterior oblique view of the left ventriculogram. d. Total infundibular defects were profiled in right anterior oblique 30 and long axial view, subaortic in location in both views

Performance Evaluation of the Concept of Hybrid Heat Pipe as Passive In-core Cooling Systems for Advanced Nuclear Power Plant

International Nuclear Information System (INIS)

Jeong, Yeong Shin; Kim, Kyung Mo; Kim, In Guk; Bang, In Cheol

2015-01-01

As an arising issue for inherent safety of nuclear power plant, the concept of hybrid heat pipe as passive in-core cooling systems was introduced. Hybrid heat pipe has unique features that it is inserted in core directly to remove decay heat from nuclear fuel without any changes of structures of existing facilities of nuclear power plant, substituting conventional control rod. Hybrid heat pipe consists of metal cladding, working fluid, wick structure, and neutron absorber. Same with working principle of the heat pipe, heat is transported by phase change of working fluid inside metal cask. Figure 1 shows the systematic design of the hybrid heat pipe cooling system. In this study, the concept of a hybrid heat pipe was introduced as a Passive IN-core Cooling Systems (PINCs) and demonstrated for internal design features of heat pipe containing neutron absorber. Using a commercial CFD code, single hybrid heat pipe model was analyzed to evaluate thermal performance in designated operating condition. Also, 1-dimensional reactor transient analysis was done by calculating temperature change of the coolant inside reactor pressure vessel using MATLAB. As a passive decay heat removal device, hybrid heat pipe was suggested with a concept of combination of heat pipe and control rod. Hybrid heat pipe has distinct feature that it can be a unique solution to cool the reactor when depressurization process is impossible so that refueling water cannot be injected into RPV by conventional ECCS. It contains neutron absorber material inside heat pipe, so it can stop the reactor and at the same time, remove decay heat in core. For evaluating the concept of hybrid heat pipe, its thermal performance was analyzed using CFD and one-dimensional transient analysis. From single hybrid heat pipe simulation, the hybrid heat pipe can transport heat from the core inside to outside about 18.20 kW, and total thermal resistance of hybrid heat pipe is 0.015 .deg. C/W. Due to unique features of long heat

[Catecholaminergic polymorphic ventricular tachycardia is a rare inherited heart disease.

DEFF Research Database (Denmark)

Holst, Anders Gaarsdal; Tfelt-Hansen, 1jacob; Olesen, Morten S

2010-01-01

Catecholaminergic polymorphic ventricular tachycardia is a rare inherited heart disease, which can lead to life-threatening ventricular arrhythmias in patients with a structurally normal heart. The age of onset is usually between two and 12 years and the initial symptom is frequently syncope...

Modernization project of the rod control system and in-core instrumentation system for 34 units of the 900 MW French EDF fleet

International Nuclear Information System (INIS)

Tavolara, Ivan; Desgeorge, Romain; Verburgh, Pierre

2014-01-01

Rolls-Royce and Cegelec, in partnership, carry out a unique and considerable modernisation project of two Instrumentation and Control (I and C) systems for the entire 900 MWe fleet of Electricite De France (EDF). Both rod control (RCS) and reactor in-core measurement (RIC) systems are to be modernised in the frame of the third ten-year renovation of all 34 reactor units over 9 power plants. The RCS contributes to the control of nuclear power by actuating control rod drive mechanisms that allow insertion or withdrawal of control rods. The RCS has also monitoring functions such as controlling the actual rods' position as well as the functional consistency between commands and actual positions. The RIC system measures in-core neutron flux, providing useful information to the control room as well as to the reactor unit computer for further processing. The renovated systems shall replace the existing ageing analog technology by modern digital technology based on PLC (Programmable Logic Controllers) and FPGA (Field-Programmable Gate Array) in the case of power subassemblies of RCS. Both systems rely for certain functions on a common network linking the RCS and RIC networks, improving operations and maintenance thanks to a powerful Man Machine Interface at the different locations of the systems with an extensive suite of tools and diagnostic menus. The project whose design phase started in July 2006 is now in its deployment phase after the successful site implementation of both systems at the first of kind units of Tricastin and Fessenheim power plants, respectively in August 2009 and February 2010. With 20 units in operation in 2014, the deployment shall continue with the other 14 until 2020. Rolls-Royce has a broad range of civil nuclear expertise, including work related to licensing and safety reviews, engineering design, supply chain management, manufacturing, installation and commissioning of the nuclear island systems and equipment, as well as operational

[Tricuspid insufficiency and right traumatic ventricular aneurysm. Apropos of a case].

Science.gov (United States)

Boisselier, P; Lombaert, M; Rey, J L; Quiret, J C; Bernasconi, P

1981-12-01

Tricuspid incompetence associated with a right ventricular aneurysm wa discovered after a non-penetrating thoracic injury. The severity of the tricuspid lesion was confirmed by phonomechanography, catheterisation and angiography. The mechanism was demonstrated by two-dimensional echocardiography: the right ventricular aneurysm was located in the right ventricular outflow tract. As the hemodynamic tolerance was good, surgery was not performed. A review of the literature found 41 other reports of traumatic tricuspid incompetence, and 4 cases of right ventricular aneurysm, only one of which was associated with tricuspid regurgitation. The points of interest of ths case: the rarity of the association, the good hemodynamic tolerance and the value of two-dimensional echocardiography for the diagnosis of ruptured chordae in the absence of surgical observations.

Ethical challenges with the left ventricular assist device as a destination therapy

Directory of Open Access Journals (Sweden)

Rady Mohamed Y

2008-08-01

Full Text Available Abstract The left ventricular assist device was originally designed to be surgically implanted as a bridge to transplantation for patients with chronic end-stage heart failure. On the basis of the REMATCH trial, the US Food and Drug Administration and the US Centers for Medicare & Medicaid Services approved permanent implantation of the left ventricular assist device as a destination therapy in Medicare beneficiaries who are not candidates for heart transplantation. The use of the left ventricular assist device as a destination therapy raises certain ethical challenges. Left ventricular assist devices can prolong the survival of average recipients compared with optimal medical management of chronic end-stage heart failure. However, the overall quality of life can be adversely affected in some recipients because of serious infections, neurologic complications, and device malfunction. Left ventricular assist devices alter end-of-life trajectories. The caregivers of recipients may experience significant burden (e.g., poor physical health, depression, anxiety, and posttraumatic stress disorder from destination therapy with left ventricular assist devices. There are also social and financial ramifications for recipients and their families. We advocate early utilization of a palliative care approach and outline prerequisite conditions so that consenting for the use of a left ventricular assist device as a destination therapy is a well informed process. These conditions include: (1 direct participation of a multidisciplinary care team, including palliative care specialists, (2 a concise plan of care for anticipated device-related complications, (3 careful surveillance and counseling for caregiver burden, (4 advance-care planning for anticipated end-of-life trajectories and timing of device deactivation, and (5 a plan to address the long-term financial burden on patients, families, and caregivers. Short-term mechanical circulatory devices (e

Right ventricular volume and mass determined by cine magnetic resonance imaging in HIV patients with possible right ventricular dysfunction

DEFF Research Database (Denmark)

Kjaer, Andreas; Lebech, Anne-Mette; Gerstoft, Jan

2006-01-01

Impaired right ventricular (RV) function has been reported to occur in patients with HIV when studied by echocardiography. However, for accurate evaluation of RV function and morphology, first-pass radionuclide ventriculography (RNV) and cine magnetic resonance imaging (cine-MRI) are methods...... ventricular ejection fraction (RVEF). To do so, we screened patients with RNV and performed an additional cine-MRI in those with reduced RVEF determined by RNV. Ninety patients with HIV were included. To evaluate the MRI measures exactly we included 18 age- and gender-matched healthy volunteers to establish...

Left ventricular function abnormalities as a manifestation of silent myocardial ischemia.

Science.gov (United States)

Lambert, C R; Conti, C R; Pepine, C J

1986-11-01

A large body of evidence exists indicating that left ventricular dysfunction is a common occurrence in patients with severe coronary artery disease and represents silent or asymptomatic myocardial ischemia. Such dysfunction probably occurs early in the time course of every ischemic episode in patients with coronary artery disease whether symptoms are eventually manifested or not. The pathophysiology of silent versus symptomatic left ventricular dysfunction due to ischemia appears to be identical. Silent ischemia-related left ventricular dysfunction can be documented during spontaneous or stress-induced perturbations in the myocardial oxygen supply/demand ratio. It also may be detected by nitroglycerin-induced improvement in ventricular function or by salutary changes in wall motion following revascularization. Silent left ventricular dysfunction is a very early occurrence during ischemia and precedes electrocardiographic abnormalities. In this light, its existence should always be kept in mind when dealing with patients with ischemic heart disease. It can be hypothesized that because silent ischemia appears to be identical to ischemia with symptoms in a pathophysiologic sense, prognosis and treatment in both cases should be the same.

Surgical myocardial revascularization in patients with reduced systolic left ventricular function.

Science.gov (United States)

Bruno, Piergiorgio; Iafrancesco, Mauro; Massetti, Massimo

2018-04-20

Surgical myocardial revascularization in patients with reduced left ventricular function has been a matter of debate for decades. Recently published 10-years extension follow-up of the STICH trial have conclusively demonstrated benefit of surgical myocardial revascularization in patients with significant coronary artery disease and low left ventricular ejection fraction. However, selection of patients for surgery remains challenging as well as decision to perform percutaneous rather than surgical revascularization in this class of patients. New evidence helped to clarify the role of preoperative patients' characteristics as risk factors for surgery and to identify those patients who may benefit the most from surgery. Focus of this review is to review epidemiology, aetiology and pathophysiology of coronary artery disease in patients with reduced left ventricular function, role of viability and results of observational and investigational studies on revascularization in patients with reduced left ventricular function with a particular emphasis on relative indication of coronary artery bypass grafting and percutaneous coronary intervention and the surgical implications of development of ischemic mitral regurgitation or ischemic left ventricular aneurysm.

Evaluation of left ventricular volumes measured by magnetic resonance imaging

DEFF Research Database (Denmark)

Møgelvang, J; Thomsen, C; Mehlsen, J

1986-01-01

Left ventricular end-diastolic and end-systolic volumes were determined in 17 patients with different levels of left ventricular function by magnetic resonance imaging (MRI). A 1.5 Tesla Magnet was used obtaining ECG triggered single and multiple slices. Calculated cardiac outputs were compared...

Association between circulating fibroblast growth factor 23, α-Klotho, and the left ventricular ejection fraction and left ventricular mass in cardiology inpatients.

Directory of Open Access Journals (Sweden)

Kensaku Shibata

Full Text Available BACKGROUND: Fibroblast growth factor 23 (FGF23, with its co-receptor Klotho, plays a crucial role in phosphate metabolism. Several recent studies suggested that circulating FGF23 and α-Klotho concentrations might be related to cardiovascular abnormalities in patients with advanced renal failure. PURPOSE: Using data from 100 cardiology inpatients who were not undergoing chronic hemodialysis, the association of circulating levels of FGF23, α-Klotho, and other calcium-phosphate metabolism-related parameters with the left ventricular ejection fraction (LVEF and left ventricular mass (LVM was analyzed. METHODS AND RESULTS: LVEF was measured using the modified Simpson method for apical 4-chamber LV images and the LVM index (LVMI was calculated by dividing the LVM by body surface area. Univariate analysis showed that log transformed FGF23, but not that of α-Klotho, was significantly associated with LVEF and LVMI with a standardized beta of -0.35 (P<0.001 and 0.26 (P<0.05, respectively. After adjusting for age, sex, estimated glomerular filtration rate, and serum concentrations of intact parathyroid hormone, and 25-hydroxyvitamin D as covariates into the statistical model, log-transformed FGF23 was found to be a statistically positive predictor for decreased left ventricular function and left ventricular hypertrophy. CONCLUSIONS: In cardiology department inpatients, circulating FGF23 concentrations were found to be associated with the left ventricular mass and LVEF independent of renal function and other calcium-phosphate metabolism-related parameters. Whether modulation of circulating FGF23 levels would improve cardiac outcome in such a high risk population awaits further investigation.

Real-time adjustment of ventricular restraint therapy in heart failure.

Science.gov (United States)

Ghanta, Ravi K; Lee, Lawrence S; Umakanthan, Ramanan; Laurence, Rita G; Fox, John A; Bolman, Ralph Morton; Cohn, Lawrence H; Chen, Frederick Y

2008-12-01

Current ventricular restraint devices do not allow for either the measurement or adjustment of ventricular restraint level. Periodic adjustment of restraint level post-device implantation may improve therapeutic efficacy. We evaluated the feasibility of an adjustable quantitative ventricular restraint (QVR) technique utilizing a fluid-filled polyurethane epicardial balloon to measure and adjust restraint level post-implantation guided by physiologic parameters. QVR balloons were implanted in nine ovine with post-infarction dilated heart failure. Restraint level was defined by the maximum restraint pressure applied by the balloon to the epicardium at end-diastole. An access line connected the balloon lumen to a subcutaneous portacath to allow percutaneous access. Restraint level was adjusted while left ventricular (LV) end-diastolic volume (EDV) and cardiac output was assessed with simultaneous transthoracic echocardiography. All nine ovine successfully underwent QVR balloon implantation. Post-implantation, restraint level could be measured percutaneously in real-time and dynamically adjusted by instillation and withdrawal of fluid from the balloon lumen. Using simultaneous echocardiography, restraint level could be adjusted based on LV EDV and cardiac output. After QVR therapy for 21 days, LV EDV decreased from 133+/-15 ml to 113+/-17 ml (p<0.05). QVR permits real-time measurement and physiologic adjustment of ventricular restraint therapy after device implantation.

A case of delayed cardiac perforation of active ventricular lead

Directory of Open Access Journals (Sweden)

Hangyuan Guo

2011-12-01

Full Text Available A 65-year-old man was admitted as for one month of repetitive dizziness and one episode of syncope. Electrocardiogram showed sinus bradycardia and his Holter monitoring also showed sinus bradycardia with sinus arrest, sino-atrial block and a longest pause of 4.3 s. Then sick sinus syndrome and Adam-Stokes syndrome were diagnosed. Then a dual chamber pacemaker (Medtronic SDR303 was implanted and the parameters were normal by detection. The patient was discharged 1 week later with suture removed. Then 1.5 month late the patient was presented to hospital once again for sudden onset of chest pain with exacerbation after taking deep breath. Pacemaker programming showed both pacing and sensing abnormality with threshold of?5.0V and resistance of 1200?. Lead perforation was revealed by chest X-ray and confirmed by echocardiogram. Considering the fact that there was high risk to remove ventricular lead, spiral tip of previous ventricular lead was withdrew followed by implantation of a new ventricular active lead to the septum. Previous ventricular lead was maintained. As we know that the complications of lead perforation in the clinic was rare. Here we discuss the clinical management and the possible reasons for cardiac perforation of active ventricular lead.

Prognostic significance of radionuclide-assessed right ventricular function in dilated cardiomyopathy

International Nuclear Information System (INIS)

Ohno, Akira; Nishimura, Tsunehiko; Uehara, Toshiisa; Shimonagata, Tsuyoshi; Kumita, Shinichiro; Ogawa, Youji; Nagata, Seiki; Miyatake, Kunio

1991-01-01

To assess the prognostic significance of right ventricular function in dilated cardiomyopathy (DCM), we studied consecutive 57 DCM patients. There were 41 men and 16 women, whose mean age was 48 years (range 3-68 years). The mean left ventricular ejection fraction (LVEF) in all patients was 29±11%, and the mean interval from the onset of symptom of cardiac failure (CHF history) was 4 years (range 0-33 years). With follow-up of 3.8 years, five patients had died until the first year, and 14 had died until the third year. By using multivariate regression analysis, there were no prognostic significance in clinical parameters such as age, CHF history, sex, atrial fibrillation, except for NYHA class, and medication at the third year. In survival curves according to Kaplan-Meier method, right ventricular ejection fraction (RVEF) and mean pulmonary artery (PA) had predictive value (p<0.05), while LVEF did not. The patients with RVEF<45% had poor survival rate compared to those with RVEF≥45%. The patients with RVEF<45% showed lower LVEF and left ventricular end-systolic volume index. RVEF may offer prognostic predictive value through the effect of not only mean PA but also left ventricular parameter. In conclusion, radionuclide assessment of right ventricular function should be valuable for the prognostic evaluation of DCM patients. (author)

Prognostic significance of radionuclide-assessed right ventricular function in dilated cardiomyopathy

Energy Technology Data Exchange (ETDEWEB)

Ohno, Akira; Nishimura, Tsunehiko; Uehara, Toshiisa; Shimonagata, Tsuyoshi; Kumita, Shinichiro; Ogawa, Youji; Nagata, Seiki; Miyatake, Kunio [National Cardiovascular Center, Suita, Osaka (Japan)

1991-09-01

To assess the prognostic significance of right ventricular function in dilated cardiomyopathy (DCM), we studied consecutive 57 DCM patients. There were 41 men and 16 women, whose mean age was 48 years (range 3-68 years). The mean left ventricular ejection fraction (LVEF) in all patients was 29{+-}11%, and the mean interval from the onset of symptom of cardiac failure (CHF history) was 4 years (range 0-33 years). With follow-up of 3.8 years, five patients had died until the first year, and 14 had died until the third year. By using multivariate regression analysis, there were no prognostic significance in clinical parameters such as age, CHF history, sex, atrial fibrillation, except for NYHA class, and medication at the third year. In survival curves according to Kaplan-Meier method, right ventricular ejection fraction (RVEF) and mean pulmonary artery (PA) had predictive value (p<0.05), while LVEF did not. The patients with RVEF<45% had poor survival rate compared to those with RVEF{>=}45%. The patients with RVEF<45% showed lower LVEF and left ventricular end-systolic volume index. RVEF may offer prognostic predictive value through the effect of not only mean PA but also left ventricular parameter. In conclusion, radionuclide assessment of right ventricular function should be valuable for the prognostic evaluation of DCM patients. (author).

Analysis of Contemporary Methods for Designing Rotary Type Ventricular Assist Devices

Directory of Open Access Journals (Sweden)

E. P. Banin

2015-01-01

Full Text Available The research object is inlet apparatus of ventricular assist device, namely inlet cannula and straightener.The purpose of the study is to reveal features of blood flow in inlet apparatus of ventricular assist device. The mathematical modeling is carried out by computational fluid dynamics analysis in a stationary setting.The first part of study concerns the analysis of existing approaches to the numerical and experimental studies in designing the ventricular assist devices of rotary type. It reveals the features of each approach for their further application in practice. The article presents an original design of developed hydraulic test bench to verify the results of mathematical modeling. Analysis of foreign authors’ studies showed that there is no enough attention paid to design of the adjacent pump assemblies of ventricular assist device. The second part of study considers direct mathematical modeling of input apparatus of ventricular assist device. The study examined straightener with three or four blades. Mathematical modeling has revealed the presence of potentially dangerous stagnation zones and essential asymmetry of the outlet flow from the input unit. The found features must be taken in consideration in designing the ventricular assist device pumps. In the future we plan to use obtained data to create a parametric model of the rotor and the diffuser considering the abovementioned features.

Significance of left ventricular volume measurement after heart transplantation using radionuclide techniques

International Nuclear Information System (INIS)

Novitzky, D.; Cooper, D.; Boniaszczuk, J.

1985-01-01

Multigated equilibrium blood pool scanning using Technetium 99m labeled red blood cells was used to measure left ventricular volumes in three heterotopic and one orthotopic heart transplant recipient(s). Simultaneously, an endomyocardial biopsy was performed and the degree of acute rejection was assessed by a histological scoring system. The scores were correlated to changes in ejection fraction and heart rate. Technetium 99m scanning data were pooled according to the endomyocardial biopsy score: no rejection; mild rejection; moderate rejection, and severe rejection. In each group, the median of the left ventricular volume parameters was calculated and correlated with the endomyocardial biopsy score, using a non-parametric one-way analysis of variance. A decrease in stroke volume correlated best with the endomyocardial biopsy score during acute rejection. A decrease in end-diastolic left ventricular volumes did not correlate as well. Changes in the end-systolic left ventricular volumes were not statistically significant, but using a simple correlation between end-systolic left ventricular volumes and endomyocardial biopsy the correlation reached significance. Changes in left ventricular volumes measured by Technetium 99m scanning may be useful to confirm the presence or absence of acute rejection in patients with heart grafts

Assessment of 123I-β-methyl iodophenyl pentadecanoic acid (BMIPP) myocardial scintigraphy in patients of chronic right ventricular overload. Fatty acid metabolism in right ventricular myocardium

International Nuclear Information System (INIS)

Mutoh, Hiroshi

1997-01-01

An investigation on the right ventricular pressure level and the abnormalities in the fatty acid metabolism of myocardium was made using 123 I-βmethyl-iodophenyl pentadecanoic acid (BMIPP) myocardial SPECT in patients with chronic right ventricular overloading. Twenty patients who presented with right ventricular systolic pressure (RVSP) of 35 mmHg or more were used as the subjects. Dual myocardial SPECT with 201 TlCl (Tl) and BMIPP was carried out for the subjects and RVc/LVc, a ratio of radioactivity count incorporated in the right ventricular free wall to the left one was determined for Tl and BMIPP. And the correlations between RVc/LVc and RVSP, and RVc/LVc and RVSP/LVSP were examined. The subjects were classified into 3 groups based on the RVSP levels and the count ratio, BMIPP/Tl was compared among the three groups. With respect of Tl uptake, there were significant, positive correlations between RVc/LVc and RVSP (correlation coefficient r=0.51, p<0.05) and between RVc/LVc and RVSP/LVSP (correlation coefficient r=0.59, p<0.01). On the other hand, no significant correlation was found between them with respect of the uptake of BMIPP. The BMIPP/Tl ratio in the group with higher than 80 mmHg of RVSP was 0.82±0.06, which was significantly lower than the ratio's for two groups of less than 80 mmHg; 0.91±0.07 and 0.98±0.04 in the group with 35-49 and 50-79 mmHg of RVSP, respectively. These results show that when compared with BMIPP, Tl is superior for the estimation of right ventricular pressure. For the patients with right ventricular overloading, it was suggested that when RVSP reaches 80 mmHg or more, there appear some disorders in the fatty acid metabolism in the right ventricular myocardium. (author)

Calculation of the ALMA Risk of Right Ventricular Failure After Left Ventricular Assist Device Implantation.

Science.gov (United States)

Loforte, Antonio; Montalto, Andrea; Musumeci, Francesco; Amarelli, Cristiano; Mariani, Carlo; Polizzi, Vincenzo; Lilla Della Monica, Paola; Grigioni, Francesco; Di Bartolomeo, Roberto; Marinelli, Giuseppe

2018-05-08

Right ventricular failure after continuous-flow left ventricular assist device (LVAD) implantation is still an unsolved issue and remains a life-threatening event for patients. We undertook this study to determine predictors of the patients who are candidates for isolated LVAD therapy as opposed to biventricular support (BVAD). We reviewed demographic, echocardiographic, hemodynamic, and laboratory variables for 258 patients who underwent both isolated LVAD implantation and unplanned BVAD because of early right ventricular failure after LVAD insertion, between 2006 and 2017 (LVAD = 170 and BVAD = 88). The final study patients were randomly divided into derivation (79.8%, n = 206) and validation (20.1%, n = 52) cohorts. Fifty-seven preoperative risk factors were compared between patients who were successfully managed with an LVAD and those who required a BVAD. Nineteen variables demonstrated statistical significance on univariable analysis. Multivariable logistic regression analysis identified destination therapy (odds ratio [OR] 2.0 [1.7-3.9], p = 0.003), a pulmonary artery pulsatility index right ventricle/left ventricle end-diastolic diameter ratio >0.75 (OR 2.7 [1.5-5.5], p = 0.001), an right ventricle stroke work index 17 (OR 3.5 [1.9-6.9], p the major predictors of the need for BVAD. Using these data, we propose a simple risk calculator to determine the suitability of patients for isolated LVAD support in the era of continuous-flow mechanical circulatory support devices.

Atrioventricular and ventricular-to-ventricular programming in patients with cardiac resynchronization therapy: results from ALTITUDE.

Science.gov (United States)

Steinberg, Benjamin A; Wehrenberg, Scott; Jackson, Kevin P; Hayes, David L; Varma, Niraj; Powell, Brian D; Day, John D; Frazier-Mills, Camille G; Stein, Kenneth M; Jones, Paul W; Piccini, Jonathan P

2015-12-01

Cardiac resynchronization therapy (CRT) improves outcomes in patients with heart failure, yet response rates are variable. We sought to determine whether physician-specified CRT programming was associated with improved outcomes. Using data from the ALTITUDE remote follow-up cohort, we examined sensed atrioventricular (AV) and ventricular-to-ventricular (VV) programming and their associated outcomes in patients with de novo CRT from 2009-2010. Outcomes included arrhythmia burden, left ventricular (LV) pacing, and all-cause mortality at 4 years. We identified 5709 patients with de novo CRT devices; at the time of implant, 34% (n = 1959) had entirely nominal settings programmed, 40% (n = 2294) had only AV timing adjusted, 11% (n = 604) had only VV timing adjusted, and 15% (n = 852) had both AV and VV adjusted from nominal programming. Suboptimal LV pacing (5% was lowest in the AV-only adjusted group (17.9%) and highest in the nominal (27.7%) and VV-only adjusted (28.3%) groups. Adjusted all-cause mortality was significantly higher among patients with non-nominal AV delay >120 vs. 180 vs. ≤180 ms, p = 0.4). Nominal settings for de novo CRT implants are frequently altered, most commonly the AV delay. There is wide variability in reprogramming. Patients with nominal or AV-only adjustments appear to have favorable pacing and arrhythmia outcomes. Sensed AV delays less than 120 ms are associated with improved survival.

Ventricular septal defect closure in a patient with achondroplasia.

Science.gov (United States)

Nakanishi, Keisuke; Kawasaki, Shiori; Amano, Atsushi

2017-01-01

Achondroplasia with co-morbid CHD is rare, as are reports of surgical treatment for such patients. We present the case of a 13-year-old girl with achondroplasia and ventricular septal defect. Her ventricular septal defect was surgically repaired focussing on the cardiopulmonary bypass flow, healing of the sternum, and her frail neck cartilage. The surgery and recovery were without complications.

Left and right ventricular dyssynchrony and strains from cardiovascular magnetic resonance feature tracking do not predict deterioration of ventricular function in patients with repaired tetralogy of Fallot.

Science.gov (United States)

Jing, Linyuan; Wehner, Gregory J; Suever, Jonathan D; Charnigo, Richard J; Alhadad, Sudad; Stearns, Evan; Mojsejenko, Dimitri; Haggerty, Christopher M; Hickey, Kelsey; Valente, Anne Marie; Geva, Tal; Powell, Andrew J; Fornwalt, Brandon K

2016-08-22

Patients with repaired tetralogy of Fallot (rTOF) suffer from progressive ventricular dysfunction decades after their surgical repair. We hypothesized that measures of ventricular strain and dyssynchrony would predict deterioration of ventricular function in patients with rTOF. A database search identified all patients at a single institution with rTOF who underwent cardiovascular magnetic resonance (CMR) at least twice, >6 months apart, without intervening surgical or catheter procedures. Seven primary predictors were derived from the first CMR using a custom feature tracking algorithm: left (LV), right (RV) and inter-ventricular dyssynchrony, LV and RV peak global circumferential strains, and LV and RV peak global longitudinal strains. Three outcomes were defined, whose changes were assessed over time: RV end-diastolic volume, and RV and LV ejection fraction. Multivariate linear mixed models were fit to investigate relationships of outcomes to predictors and ten potential baseline confounders. One hundred fifty-three patients with rTOF (23 ± 14 years, 50 % male) were included. The mean follow-up duration between the first and last CMR was 2.9 ± 1.3 years. After adjustment for confounders, none of the 7 primary predictors were significantly associated with change over time in the 3 outcome variables. Only 1-17 % of the variability in the change over time in the outcome variables was explained by the baseline predictors and potential confounders. In patients with repaired tetralogy of Fallot, ventricular dyssynchrony and global strain derived from cine CMR were not significantly related to changes in ventricular size and function over time. The ability to predict deterioration in ventricular function in patients with rTOF using current methods is limited.

Wave Intensity Analysis of Right Ventricular Function during Pulsed Operation of Rotary Left Ventricular Assist Devices.

Science.gov (United States)

Bouwmeester, J Christopher; Park, Jiheum; Valdovinos, John; Bonde, Pramod

2018-05-29

Changing the speed of left ventricular assist devices (LVADs) cyclically may be useful to restore aortic pulsatility; however, the effects of this pulsation on right ventricular (RV) function are unknown. This study investigates the effects of direct ventricular interaction by quantifying the amount of wave energy created by RV contraction when axial and centrifugal LVADs are used to assist the left ventricle. In 4 anesthetized pigs, pressure and flow were measured in the main pulmonary artery and wave intensity analysis was used to identify and quantify the energy of waves created by the RV. The axial pump depressed the intensity of waves created by RV contraction compared with the centrifugal pump. In both pump designs, there were only minor and variable differences between the continuous and pulsed operation on RV function. The axial pump causes the RV to contract with less energy compared with a centrifugal design. Diminishing the ability of the RV to produce less energy translates to less pressure and flow produced, which may lead to LVAD-induced RV failure. The effects of pulsed LVAD operation on the RV appear to be minimal during acute observation of healthy hearts. Further study is necessary to uncover the effects of other modes of speed modulation with healthy and unhealthy hearts to determine if pulsed operation will benefit patients by reducing LVAD complications.

Early Right Ventricular Apical Pacing-Induced Gene Expression Alterations Are Associated with Deterioration of Left Ventricular Systolic Function

Directory of Open Access Journals (Sweden)

Haiyan Xu

2017-01-01

Full Text Available The chronic high-dose right ventricular apical (RVA pacing may have deleterious effects on left ventricular (LV systolic function. We hypothesized that the expression changes of genes regulating cardiomyocyte energy metabolism and contractility were associated with deterioration of LV function in patients who underwent chronic RVA pacing. Sixty patients with complete atrioventricular block and preserved ejection fraction (EF who underwent pacemaker implantation were randomly assigned to either RVA pacing (n=30 group or right ventricular outflow tract (RVOT pacing (n=30 group. The mRNA levels of OPA1 and SERCA2a were significantly lower in the RVA pacing group at 1 month’s follow-up (both p<0.001. Early changes in the expression of selected genes OPA1 and SERCA2a were associated with deterioration in global longitudinal strain (GLS that became apparent months later (p=0.002 and p=0.026, resp. The altered expressions of genes that regulate cardiomyocyte energy metabolism and contractility measured in the peripheral blood at one month following pacemaker implantation were associated with subsequent deterioration in LV dyssynchrony and function in patients with preserved LVEF, who underwent RVA pacing.

Influence of age on left ventricular performance during exercise in normal Japanese subject

International Nuclear Information System (INIS)

Konishi, Tokuji; Koyama, Takao; Aoki, Toshikazu; Makino, Katsutoshi; Yamamuro, Masashi; Nakai, Kyudayu; Nakamura, Masayuki; Nakano, Takeshi.

1990-01-01

To assess the effects of age on left ventricular performance, multistage supine ergometer exercise radionuclide ventriculography (RNV) was performed in 92 normal subjects. The subjects ranged in age from 24 to 86 years and were free of cardiopulmonary disease and diabetes. Age-related changes in exercise duration, left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), cardiac output (CO) left ventricular ejection fraction (LVEF), left ventricular dv/dt, systolic and diastolic time indexes of dv/dt, and peak systolic pressure/left ventricular end-systolic volume (PSP/LVESV) were analyzed at rest and during the peak exercise stage. Age-related decrease in LVEDV and peak diastolic dv/dt were significant at rest. The time indexes of ECG R to peak systolic dv/dt and time of end-systole to peak diastolic dv/dt also were prolonged with age. Both maximum heart rate and exercise duration were shown to decline with age. No age-related difference was observed in LVESV, LVEF or PSP/LVESV either at rest or during exercise. However, the change of LVEF and LVESV during exercise was less in subjects aged 60 or more. These results indicate decreased left ventricular function during exercise in elderly subjects. (author)

Diclofenac Prolongs Repolarization in Ventricular Muscle with Impaired Repolarization Reserve

Science.gov (United States)

Kristóf, Attila; Husti, Zoltán; Koncz, István; Kohajda, Zsófia; Szél, Tamás; Juhász, Viktor; Biliczki, Péter; Jost, Norbert; Baczkó, István; Papp, Julius Gy; Varró, András; Virág, László

2012-01-01

Background The aim of the present work was to characterize the electrophysiological effects of the non-steroidal anti-inflammatory drug diclofenac and to study the possible proarrhythmic potency of the drug in ventricular muscle. Methods Ion currents were recorded using voltage clamp technique in canine single ventricular cells and action potentials were obtained from canine ventricular preparations using microelectrodes. The proarrhythmic potency of the drug was investigated in an anaesthetized rabbit proarrhythmia model. Results Action potentials were slightly lengthened in ventricular muscle but were shortened in Purkinje fibers by diclofenac (20 µM). The maximum upstroke velocity was decreased in both preparations. Larger repolarization prolongation was observed when repolarization reserve was impaired by previous BaCl2 application. Diclofenac (3 mg/kg) did not prolong while dofetilide (25 µg/kg) significantly lengthened the QTc interval in anaesthetized rabbits. The addition of diclofenac following reduction of repolarization reserve by dofetilide further prolonged QTc. Diclofenac alone did not induce Torsades de Pointes ventricular tachycardia (TdP) while TdP incidence following dofetilide was 20%. However, the combination of diclofenac and dofetilide significantly increased TdP incidence (62%). In single ventricular cells diclofenac (30 µM) decreased the amplitude of rapid (IKr) and slow (IKs) delayed rectifier currents thereby attenuating repolarization reserve. L-type calcium current (ICa) was slightly diminished, but the transient outward (Ito) and inward rectifier (IK1) potassium currents were not influenced. Conclusions Diclofenac at therapeutic concentrations and even at high dose does not prolong repolarization markedly and does not increase the risk of arrhythmia in normal heart. However, high dose diclofenac treatment may lengthen repolarization and enhance proarrhythmic risk in hearts with reduced repolarization reserve. PMID:23300901

Failure of antiarrhythmic drugs to prevent experimental reperfusion ventricular fibrillation.

Science.gov (United States)

Naito, M; Michelson, E L; Kmetzo, J J; Kaplinsky, E; Dreifus, L S

1981-01-01

Ninety-nine adult mongrel dogs underwent acute ligation of the proximal left anterior descending coronary artery. Thirty minutes later, the occlusion was released to evaluate the effectiveness of five antiarrhythmic protocols in eliminating reperfusion ventricular fibrillation. The five protocols included: protocol 1 --i.v. lidocaine, preligation and prerelease (n = 19); protocol 2 -- i.v. lidocaine, prereperfusion only (n = 22); protocol 3 -- chronic, oral, daily amiodarone for 2 weeks preligation (n = 19); protocol 4 -- i.v. procainamide, preligation and prereperfusion (n = 21); and protocol 5 -- i.v. verapamil, prereperfusion (n = 18). Each regimen was evaluated with respect to the incidence of reperfusion ventricular fibrillation in dogs that survived to reperfusion, and the results were compared to 77 control dogs that underwent identical coronary artery occlusion and release procedures without drug therapy. The incidence of reperfusion ventricular fibrillation was as follows: protocol 1 -- seven of 15 dogs (47%); protocol 2 -- six of 18 (33%); protocol 3 -- 11 of 16 dogs (69%); protocol 4 -- eight of 17 dogs (47%); and protocol 5 -- 10 of 17 dogs (59%), compared with 36 of 60 (60%) in control dogs. Using chi-square analysis, protocol 2 was beneficial (p antecedent coronary artery ligation periods, and predictive risk indexes for the occurrence of reperfusion ventricular fibrillation were developed. the Mantel-Haenszel method of statistical analysis revealed that none of these protocols resulted in a statistically significant reduction in the incidence of reperfusion ventricular fibrillation. Thus, use of these predictive indexes plus appropriate statistical methods has revealed, unexpectedly, limitations in the efficacy of a spectrum of antiarrhythmic agents in preventing reperfusion ventricular fibrillation.

Intraoperative Hemodynamic and Echocardiographic Measurements Associated With Severe Right Ventricular Failure After Left Ventricular Assist Device Implantation.

Science.gov (United States)

Gudejko, Michael D; Gebhardt, Brian R; Zahedi, Farhad; Jain, Ankit; Breeze, Janis L; Lawrence, Matthew R; Shernan, Stanton K; Kapur, Navin K; Kiernan, Michael S; Couper, Greg; Cobey, Frederick C

2018-06-05

Severe right ventricular failure (RVF) after left ventricular assist device (LVAD) implantation increases morbidity and mortality. We investigated the association between intraoperative right heart hemodynamic data, echocardiographic parameters, and severe versus nonsevere RVF. A review of LVAD patients between March 2013 and March 2016 was performed. Severe RVF was defined by the need for a right ventricular mechanical support device, inotropic, and/or inhaled pulmonary vasodilator requirements for >14 days. From a chart review, the right ventricular failure risk score was calculated and right heart hemodynamic data were collected. Pulmonary artery pulsatility index (PAPi) [(pulmonary artery systolic pressure - pulmonary artery diastolic pressure)/central venous pressure (CVP)] was calculated for 2 periods: (1) 30 minutes before cardiopulmonary bypass (CPB) and (2) after chest closure. Echocardiographic data were recorded pre-CPB and post-CPB by a blinded reviewer. Univariate logistic regression models were used to examine the performance of hemodynamic and echocardiographic metrics. A total of 110 LVAD patients were identified. Twenty-five did not meet criteria for RVF. Of the remaining 85 patients, 28 (33%) met criteria for severe RVF. Hemodynamic factors associated with severe RVF included: higher CVP values after chest closure (18 ± 9 vs 13 ± 5 mm Hg; P = .0008) in addition to lower PAPi pre-CPB (1.2 ± 0.6 vs 1.7 ± 1.0; P = .04) and after chest closure (0.9 ± 0.5 vs 1.5 ± 0.8; P = .0008). Post-CPB echocardiographic findings associated with severe RVF included: larger right atrial diameter major axis (5.4 ± 0.9 vs 4.9 ± 1.0 cm; P = .03), larger right ventricle end-systolic area (22.6 ± 8.4 vs 18.5 ± 7.9 cm; P = .03), lower fractional area of change (20.2 ± 10.8 vs 25.9 ± 12.6; P = .04), and lower tricuspid annular plane systolic excursion (0.9 ± 0.2 vs 1.1 ± 0.3 cm; P = .008). Right ventricular failure risk score was not a significant predictor of

Clinical application of a right ventricular pressure-volume loop determined by gated blood-pool imaging and simultaneously measured right ventricular pressure

International Nuclear Information System (INIS)

Yasue, Takao; Watanabe, Sachiro; Sugishita, Nobuyoshi; Tanaka, Tsutomu; Yokoyama, Hideo

1983-01-01

The data obtained by ECG-gated radionuclide angiography were collected simultaneously with right ventricular pressure and thermal cardiac output (CO) obtained by a Swan-Ganz catheter in Scintipac 1200 (Shimazu Co) in order to create a right ventricular pressure-volume (RV P-V) loop. Subjects consisted of 15 patients with old myocardial infarction (MI group), seven with angina pectoris (AP group), six with congestive cardiomyopathy (CCM group) and five with neurocirculatory asthenia (NCA group). Right ventricular end-diastolic volume (RVEDV) was calculated as RVEDV = CO/(EF x HR) (CO = cardiac output; HR = heart rate). Systolic work (W sub(S)), diastolic work (W sub(D)) and net work (W sub(N)) were calculated from a RV P-V loop by Simpson's method. The measurements were performed before and 5 min after sublingual administration of nitroglycerin (NG) (0.3 mg). The results were as follows: 1. RV P-V loops shifted towards the left lower part of the P-V plane after sublingual administration of nitroglycerin, indicating the reduction of pressure and volume of the right ventricle. 2. Right ventricular ejection fraction (RVEF) in the MI, AP and CCM groups showed smaller values than that of the NCA group. 3. Right ventricular end-diastolic volume index (RVEDVI) showed a converse relation with RVEF. 4. Cardiac index in all groups decreased after NG and a statistical significance was seen in the MI, AP and NCA groups (p<0.05). 5. RV W sub(S), RV W sub(D) and RV W sub(N) showed no difference among each groups in the control state, and significantly decreased after NG. We conclude that the present method using RV P-V loop might be useful as a noninvasive bedside monitoring and permits the evaluation of RV function in a clinical setting

Regional ejection fraction: a quantitative radionuclide index of regional left ventricular performance

International Nuclear Information System (INIS)

Maddox, D.E.; Wynne, J.; Uren, R.; Parker, J.A.; Idoine, J.; Siegel, L.C.; Neill, J.M.; Cohn, P.F.; Holman, B.L.

1979-01-01

Left ventricular regional ejection fractions were derived from background-corrected, time-activity curves in 43 patients assessed by both gated equilibrium radionuclide angiocardiography and left ventricular contrast angiography. From a single, modified left anterior oblique projection, the regional change in background corrected counts was determined in each of three anatomic regions. The normal range for regional radionuclide ejection fraction was determined in 10 patients with normal contrast ventriculograms and without obstructive coronary artery disease at coronary arteriography. Regional ejection fraction was compared with percent segmental axis shortening and extent of akinetic segments in corresponding regions of the contrast ventriculogram. Radionuclide and roentgenographic methods were in agreement as to the presence or absence of abnormal wall motion in 83 of 99 left ventricular regions (84%) in 33 patients evaluated prospectively. Comparison of regional ejection fraction demonstrated significant differences between regions with roentgenographically determined normokinesis hypokinesis, and akinesis. We conclude that the left ventricular regional ejection fraction provides a reliable quantitative assessment of regional left ventricular performance

New strict left bundle branch block criteria reflect left ventricular activation differences

DEFF Research Database (Denmark)

Emerek, Kasper Janus Grønn; Risum, Niels; Hjortshøj, Søren Pihlkjær

2015-01-01

AIMS: Pacing lead electrical delays and strict left bundle branch block (LBBB) criteria were assessed against cardiac resynchronization therapy (CRT) outcome. METHODS: Forty-nine patients with LBBB and QRS duration >130 milliseconds underwent CRT-implantation. Sensed right ventricular to left ven....... CONCLUSION: Interventricular electrical delay predicts left ventricular remodeling after CRT and new, strict ECG criteria of LBBB are superior in predicting remodeling.......AIMS: Pacing lead electrical delays and strict left bundle branch block (LBBB) criteria were assessed against cardiac resynchronization therapy (CRT) outcome. METHODS: Forty-nine patients with LBBB and QRS duration >130 milliseconds underwent CRT-implantation. Sensed right ventricular to left...... ventricular electrical delay (RV-LV-IED) was measured. Response to CRT was defined as ≥15% decrease in left ventricular end-systolic volume. RESULTS: Eighteen of 20 (90%) patients with non-ischemic dilated cardiomyopathy (DCM) and 18 of 29 (62%) with ischemic heart disease (IHD) responded to CRT, p

Management of Arrhythmias in Athletes: Atrial Fibrillation, Premature Ventricular Contractions, and Ventricular Tachycardia.

Science.gov (United States)

Lai, Ernest; Chung, Eugene H

2017-10-09

Management of atrial fibrillation, premature ventricular contractions, and ventricular tachycardia without underlying cardiac disease or arrhythmogenic conditions differs in athletes from the general population. Athletes tend to be younger, healthier individuals with few comorbidities. Therapies that work well in the general population may not be appropriate or preferable for athletes. Management strategies include deconditioning, pharmacologic therapy, such as rate control with β-blockers or non-dihydropyridine calcium channel blockers and rhythm control with class I or class III antiarrhythmic drugs, and catheter ablation. Deconditioning is not preferred by athletes because of lost playing time. Pharmacologic therapy is well tolerated among most individuals, but is not as favorable in athletes. Rate control medications can reduce performance and β-blockers, in particular, are prohibited in many sports. Antiarrhythmic drugs are preferred over rate control with athletes, but many, especially younger athletes, may not like the idea of long-term medical therapy. Catheter ablation has been proven to be safe and efficacious, may eliminate the need for long-term medical therapy, and is supported by the major societies (AHA, ACC, ESC).

Applications of magnetic resonance imaging in the assessment of left ventricular dysfunction

Energy Technology Data Exchange (ETDEWEB)

Beacock, David John

2002-07-01

This thesis has described the use of Magnetic Resonance Imaging (MRI) in the investigation of left ventricular dimensions and systolic function. This has been performed in conditions of left ventricular dysfunction, in congestive cardiac failure and following anterior myocardial infarction. The reproducibility of measurements of left ventricular dimensions using MRI has been presented. Such measurements were shown to be reproducible between different MRI studies of normal volunteers and patients with congestive heart failure. Furthermore, measurements from different MRI studies obtained from two commercially different systems were reproducible for the same subject groups. Ventricular dimensions and systolic function was evaluated in adult normal volunteers of different ages. Although left ventricular volumes and mass remained unchanged, detailed studies of the systolic images revealed significant differences between the two age groups. Differences in left ventricular cavity volumes and mass between patients with congestive heart failure and age-matched normal volunteers were also investigated. Left ventricular volumes and myocardial mass were assessed in a group of patients following anterior myocardial infarction. End-systolic volume was significantly increased compared to age-matched volunteers, but no changes in end-diastolic volume or myocardial mass was observed. Serial re-evaluation of these patients revealed no other changes over the subsequent six months. All these patients were treated with optimal medical therapy (thrombolysis, aspirin, beta-blockade and angiotensin converting enzyme inhibition). Thus, the use of this therapy may attenuate the process of left ventricular remodelling. Regional wall thickness was measured in the post-infarct patients. Wall thickening was significantly reduced both in the infarcted regions and in myocardium remote to the infarction. In contrast to previous echocardiographic studies, no 'hypercontractility' was

El CO2 como disolvente y como reactivo

OpenAIRE

La Franca Pitarresi, Vincenzo Rosario

2016-01-01

Existen numerosas ventajas asociada con el uso de CO2 , tanto como disolvente que como reactivo, y todas se pueden resumir en cuatro categorías generales: beneficios ambiental, beneficios de salud y seguridad, beneficios en el procedimiento y beneficios químicos. Los procesos que implican el CO2 como disolvente no aumentaría las emisiones de CO2, más bien proporcionaría una oportunidad para el reciclaje de CO2 residual. Además, los esfuerzos para secuestrar el CO2 producido de los gases de co...

Clinical value of regression of electrocardiographic left ventricular hypertrophy after aortic valve replacement.

Science.gov (United States)

Yamabe, Sayuri; Dohi, Yoshihiro; Higashi, Akifumi; Kinoshita, Hiroki; Sada, Yoshiharu; Hidaka, Takayuki; Kurisu, Satoshi; Shiode, Nobuo; Kihara, Yasuki

2016-09-01

Electrocardiographic left ventricular hypertrophy (ECG-LVH) gradually regressed after aortic valve replacement (AVR) in patients with severe aortic stenosis. Sokolow-Lyon voltage (SV1 + RV5/6) is possibly the most widely used criterion for ECG-LVH. The aim of this study was to determine whether decrease in Sokolow-Lyon voltage reflects left ventricular reverse remodeling detected by echocardiography after AVR. Of 129 consecutive patients who underwent AVR for severe aortic stenosis, 38 patients with preoperative ECG-LVH, defined by SV1 + RV5/6 of ≥3.5 mV, were enrolled in this study. Electrocardiography and echocardiography were performed preoperatively and 1 year postoperatively. The patients were divided into ECG-LVH regression group (n = 19) and non-regression group (n = 19) according to the median value of the absolute regression in SV1 + RV5/6. Multivariate logistic regression analysis was performed to assess determinants of ECG-LVH regression among echocardiographic indices. ECG-LVH regression group showed significantly greater decrease in left ventricular mass index and left ventricular dimensions than Non-regression group. ECG-LVH regression was independently determined by decrease in the left ventricular mass index [odds ratio (OR) 1.28, 95 % confidence interval (CI) 1.03-1.69, p = 0.048], left ventricular end-diastolic dimension (OR 1.18, 95 % CI 1.03-1.41, p = 0.014), and left ventricular end-systolic dimension (OR 1.24, 95 % CI 1.06-1.52, p = 0.0047). ECG-LVH regression could be a marker of the effect of AVR on both reducing the left ventricular mass index and left ventricular dimensions. The effect of AVR on reverse remodeling can be estimated, at least in part, by regression of ECG-LVH.

Stunning and Right Ventricular Dysfunction Is Induced by Coronary Balloon Occlusion and Rapid Pacing in Humans: Insights From Right Ventricular Conductance Catheter Studies.

Science.gov (United States)

Axell, Richard G; Giblett, Joel P; White, Paul A; Klein, Andrew; Hampton-Til, James; O'Sullivan, Michael; Braganza, Denise; Davies, William R; West, Nick E J; Densem, Cameron G; Hoole, Stephen P

2017-06-06

We sought to determine whether right ventricular stunning could be detected after supply (during coronary balloon occlusion [BO]) and supply/demand ischemia (induced by rapid pacing [RP] during transcatheter aortic valve replacement) in humans. Ten subjects with single-vessel right coronary artery disease undergoing percutaneous coronary intervention with normal ventricular function were studied in the BO group. Ten subjects undergoing transfemoral transcatheter aortic valve replacement were studied in the RP group. In both, a conductance catheter was placed into the right ventricle, and pressure volume loops were recorded at baseline and for intervals over 15 minutes after a low-pressure BO for 1 minute or a cumulative duration of RP for up to 1 minute. Ischemia-induced diastolic dysfunction was seen 1 minute after RP (end-diastolic pressure [mm Hg]: 8.1±4.2 versus 12.1±4.1, P right coronary artery balloon occlusion both cause ischemic right ventricular dysfunction with stunning observed later during the procedure. This may have intraoperative implications in patients without right ventricular functional reserve. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

CT and MRI findings of 4th ventricular tumors

International Nuclear Information System (INIS)

Kim, Taek Geun; Ro, Hee Jeong; Byun, Jae Young; Lee, Han Jin; Chung, Myung Hee; Choi, Kyu Ho; Shinn, Kyung Sub

1994-01-01

The purpose of our study is to evaluate characteristic features of 4th ventricular tumors in CT and MRI. Pathologically proved 9 patients with 4th ventricular tumor were examined by CT and/or MRI. 4th ventricular tumors were ependymoma(4 cases), medulloblastoma(2 case), choroid plexus papilloma(2 cases), and oligodendroglioma(1 cases). Include in our study were only those mass lesions that were located at surgery predominantly within 4th ventricle with or without ventricular expansion. The origin of 4th ventricular tumor was the roof (ependymoma 3 cases, medulloblastoma 2 cases), the floor (ependymoma 1 cases), and the undetermined(remaining 3 case). On MRI, all tumors were hypointense except ependymoma (3 cases) showing isointensity on T1WI. All tumors were hypointense on PDWI and T2WI. On Gd-DTPA enhanced T1WI, strong enhancement was seen in all but ependymoma(1 cases) which showed mild enhancement. On CT, as compared with MR images, various density on precontrast and postcontrast images were seen. Calcification was seen in choroid plexus papilloma(1 caes) and oligodendroglioma(1 cases). Hydrocephalus is seen in all cases except ependymoma(2 cases) and oligodendroglioma(1 case). Hemorrhage within tumor was present only in ependymoma(2 cases). Cystic change or necrosis of tumor was seen in ependymoma(3 cases), choroid plexus papilloma(1 case), and oligodendroglioma(1 case). Peritumoral edema was seen in medulloblastoma(1 case). Extension through the foramen Luschka and the Megendie was seen in ependymoma (2 cases), choroid plexus(2 cases), and medulloblastoma (1 case). Seeing along the CSF pathway was seen only in ependymoma(2 case). The results od our study may suggest that specific diagnosis of 4th ventricular tumor can be suggested preoperatively by analysing the origin in 4th ventricle, difference of CT density or MRI signal intensity, presence of extension or seeding through cerebrospinal fluid of the lesion

Repaired tetralogy of Fallot with coexisting unrepaired partial anomalous pulmonary venous connection is associated with diminished right ventricular ejection fraction and more severe right ventricular dilation

International Nuclear Information System (INIS)

Chan, Sherwin S.; Whitehead, Kevin K.; Kim, Timothy S.; Fu, Gregory L.; Fogel, Mark A.; Harris, Matthew A.; Keller, Marc S.

2015-01-01

There is an established association between tetralogy of Fallot and partial anomalous pulmonary venous connections. This association is important because surgically repaired tetralogy patients have increased risk of right heart failure. We hypothesize that partial anomalous venous connections increase right ventricular volumes and worsen right ventricular failure. We reviewed cardiac MRI exams performed at a tertiary pediatric hospital from January 2005 to January 2014. We identified patients with repaired tetralogy and unrepaired partial anomalous pulmonary venous connection. We used age- and gender-matched repaired tetralogy patients without partial anomalous pulmonary venous connection as controls. We analyzed the MRI results and surgical course and performed comparative statistics to identify group differences. There were eight patients with repaired tetralogy and unrepaired partial anomalous pulmonary venous connection and 16 controls. In all cases, the partial anomalous pulmonary venous connection was not detected on preoperative echocardiography. There were no significant differences in surgical course and body surface area between the two groups. Repaired tetralogy patients with unrepaired partial anomalous pulmonary venous connection showed significantly higher indexed right ventricular end diastolic volume (149 ± 33 mL/m 2 vs. 118 ± 30 mL/m 2 ), right ventricle to left ventricle size ratios (3.1 ± 1.3 vs. 1.9 ± 0.5) and a higher incidence of reduced right ventricular ejection fraction compared to controls (3/8 vs. 0/16). Repaired tetralogy of Fallot with unrepaired partial anomalous pulmonary venous connection is associated with reduced right ventricular ejection fraction and more significant right ventricular dilation. (orig.)

Repaired tetralogy of Fallot with coexisting unrepaired partial anomalous pulmonary venous connection is associated with diminished right ventricular ejection fraction and more severe right ventricular dilation

Energy Technology Data Exchange (ETDEWEB)

Chan, Sherwin S. [Children' s Mercy Hospital and Clinics, Department of Radiology, Kansas City, MO (United States); Whitehead, Kevin K.; Kim, Timothy S.; Fu, Gregory L.; Fogel, Mark A.; Harris, Matthew A. [Children' s Hospital of Philadelphia, Department of Cardiology, Philadelphia, PA (United States); Keller, Marc S. [Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States)

2015-09-15

There is an established association between tetralogy of Fallot and partial anomalous pulmonary venous connections. This association is important because surgically repaired tetralogy patients have increased risk of right heart failure. We hypothesize that partial anomalous venous connections increase right ventricular volumes and worsen right ventricular failure. We reviewed cardiac MRI exams performed at a tertiary pediatric hospital from January 2005 to January 2014. We identified patients with repaired tetralogy and unrepaired partial anomalous pulmonary venous connection. We used age- and gender-matched repaired tetralogy patients without partial anomalous pulmonary venous connection as controls. We analyzed the MRI results and surgical course and performed comparative statistics to identify group differences. There were eight patients with repaired tetralogy and unrepaired partial anomalous pulmonary venous connection and 16 controls. In all cases, the partial anomalous pulmonary venous connection was not detected on preoperative echocardiography. There were no significant differences in surgical course and body surface area between the two groups. Repaired tetralogy patients with unrepaired partial anomalous pulmonary venous connection showed significantly higher indexed right ventricular end diastolic volume (149 ± 33 mL/m{sup 2} vs. 118 ± 30 mL/m{sup 2}), right ventricle to left ventricle size ratios (3.1 ± 1.3 vs. 1.9 ± 0.5) and a higher incidence of reduced right ventricular ejection fraction compared to controls (3/8 vs. 0/16). Repaired tetralogy of Fallot with unrepaired partial anomalous pulmonary venous connection is associated with reduced right ventricular ejection fraction and more significant right ventricular dilation. (orig.)

Continuous monitoring of left ventricular function by VEST

International Nuclear Information System (INIS)

Ohtake, Tohru; Watanabe, Toshiaki; Kosaka, Noboru

1988-01-01

Using an ambulatory ventricular function monitor (VEST), left ventricular function (LVF) was examined in one healthy volunteer, 3 with ischemic heart disease, and one with dilated myocardiopathy (DMCP) under various conditions, such as treadmill exercise, standing, and sitting. It was also examined when two DCMP patients with associated left ventricular failure were given a nitrite (ISDM) and cardiotonic agent (E 1020). End-diastolic volume (EDV) decreased in the standing position, and increased in exercise, suggesting the involvement of venous blood pool in the legs. Ejection fraction (EF) decreased in the case of widespread ischemia during exercise. Drug tolerance test revealed decrease in EDV and end-systolic volume (ESV), no change in stroke volume (SV), and slight increase in EF on ISDM; and decrease in EDV and ESV, increase in SV, and marked increase in EF on E 1020. For EF, the VEST data were relatively well correlated with gamma camera data. (Namekawa, K.)

Value of the radiological study of the thorax for diagnosing left ventricular dysfunction in Chagas' disease

Directory of Open Access Journals (Sweden)

Perez Amanda Arantes

2003-01-01

Full Text Available OBJECTIVE: To determine the value of the radiological study of the thorax for diagnosing left ventricular dilation and left ventricular systolic dysfunction in patients with Chagas' disease. METHODS: A cross-sectional study of 166 consecutive patients with Chagas' disease and no other associated diseases. The patients underwent cardiac assessment with chest radiography and Doppler echocardiography. Sensitivity, specificity, and positive and negative predictive values of chest radiography were calculated to detect left ventricular dysfunction and the accuracy of the cardiothoracic ratio in the diagnosis of left ventricular dysfunction with the area below the ROC curve. The cardiothoracic ratio was correlated with the left ventricular ejection fraction and the left ventricular diastolic diameter. RESULTS: The abnormal chest radiogram had a sensitivity of 50%, specificity of 80.5%, and positive and negative predictive values of 51.2% and 79.8%, respectively, in the diagnosis of left ventricular dysfunction. The cardiothoracic ratio showed a weak correlation with left ventricular ejection fraction (r=-0.23 and left ventricular diastolic diameter (r=0.30. The area calculated under the ROC curve was 0.734. CONCLUSION: The radiological study of the thorax is not an accurate indicator of left ventricular dysfunction; its use as a screening method to initially approach the patient with Chagas' disease should be reevaluated.

Signal analysis of ventricular fibrillation

NARCIS (Netherlands)

Herbschleb, J.N.; Heethaar, R.M.; Tweel, L.H. van der; Zimmerman, A.N.E.; Meijler, F.L.

Signal analysis of electro(cardio)grams during ventricular fibrillation (VF) in dogs and human patients indicates more organization and regularity than the official WHO definition suggests. The majority of the signal is characterized by a power spectrum with narrow, equidistant peaks. In a further

Diabetes Mellitus Associates with Increased Right Ventricular Afterload and Remodeling in Pulmonary Arterial Hypertension.

Science.gov (United States)

Whitaker, Morgan E; Nair, Vineet; Sinari, Shripad; Dherange, Parinita A; Natarajan, Balaji; Trutter, Lindsey; Brittain, Evan L; Hemnes, Anna R; Austin, Eric D; Patel, Kumar; Black, Stephen M; Garcia, Joe G N; Yuan Md PhD, Jason X; Vanderpool, Rebecca R; Rischard, Franz; Makino, Ayako; Bedrick, Edward J; Desai, Ankit A

2018-06-01

Diabetes mellitus is associated with left ventricular hypertrophy and dysfunction. Parallel studies have also reported associations between diabetes mellitus and right ventricular dysfunction and reduced survival in patients with pulmonary arterial hypertension. However, the impact of diabetes mellitus on the pulmonary vasculature has not been well characterized. We hypothesized that diabetes mellitus and hyperglycemia could specifically influence right ventricular afterload and remodeling in patients with Group I pulmonary arterial hypertension, providing a link to their known susceptibility to right ventricular dysfunction. Using an adjusted model for age, sex, pulmonary vascular resistance, and medication use, associations of fasting blood glucose, glycated hemoglobin, and the presence of diabetes mellitus were evaluated with markers of disease severity in 162 patients with pulmonary arterial hypertension. A surrogate measure of increased pulmonary artery stiffness, elevated pulmonary arterial elastance (P = .012), along with reduced log(pulmonary artery capacitance) (P = .006) were significantly associated with the presence of diabetes mellitus in patients with pulmonary arterial hypertension in a fully adjusted model. Similar associations between pulmonary arterial elastance and capacitance were noted with both fasting blood glucose and glycated hemoglobin. Furthermore, right ventricular wall thickness on echocardiography was greater in pulmonary arterial hypertension patients with diabetes, supporting the link between right ventricular remodeling and diabetes. Cumulatively, these data demonstrate that an increase in right ventricular afterload, beyond pulmonary vascular resistance alone, may influence right ventricular remodeling and provide a mechanistic link between the susceptibility to right ventricular dysfunction in patients with both diabetes mellitus and pulmonary arterial hypertension. Copyright © 2018 Elsevier Inc. All rights reserved.

Small angle neutron scattering study of nano sized microstructure in Fe-Cr ODS steels for gen IV in-core applications.

Science.gov (United States)

Han, Young-Soo; Mao, Xiadong; Jang, Jinsung

2013-11-01

The nano-sized microstructures in Fe-Cr oxide dispersion strengthened steel for Gen IV in-core applications were studied using small angle neutron scattering. The oxide dispersion strengthened steel was manufactured through hot isostatic pressing with various chemical compositions and fabrication conditions. Small angle neutron scattering experiments were performed using a 40 m small angle neutron scattering instrument at HANARO. Nano sized microstructures, namely, yttrium oxides and Cr-oxides were quantitatively analyzed by small angle neutron scattering. The yttrium oxides and Cr-oxides were also observed by transmission electron microscopy. The microstructural analysis results from small angle neutron scattering were compared with those obtained by transmission electron microscopy. The effects of the chemical compositions and fabrication conditions on the microstructure were investigated in relation to the quantitative microstructural analysis results obtained by small angle neutron scattering. The volume fraction of Y-oxide increases after fabrication, and this result is considered to be due to the formation of non-stochiometric Y-Ti-oxides.

A novel implantable electromechanical ventricular assist device - First acute animal testing

NARCIS (Netherlands)

Kaufmann, R; Rakhorst, G; Mihaylov, D; Elstrodt, J; Nix, C; Reul, H; Rau, G

1997-01-01

A novel ventricular assist device (HIA-EMLVAD-AT1, Helmholtz Institute Aachen-electromechanical Left Ventricular Assist Device-Animal Test Version 1), driven by a uniformly and unidirectionally rotating actuator and a patented hypocycloidic pusherplate displacement gear unit, was developed and

Computational model based approach to analysis ventricular arrhythmias: Effects of dysfunction calcium channels

Science.gov (United States)

Gulothungan, G.; Malathi, R.

2018-04-01

Disturbed sodium (Na+) and calcium (Ca2+) handling is known to be a major predisposing factor for life-threatening cardiac arrhythmias. Cardiac contractility in ventricular tissue is prominent by Ca2+ channels like voltage dependent Ca2+ channels, sodium-calcium exchanger (Na+-Ca2+x) and sacroplasmicrecticulum (SR) Ca2+ pump and leakage channels. Experimental and clinical possibilities for studying cardiac arrhythmias in human ventricular myocardium are very limited. Therefore, the use of alternative methods such as computer simulations is of great importance. Our aim of this article is to study the impact on action potential (AP) generation and propagation in single ventricular myocyte and ventricular tissue under different dysfunction Ca2+ channels condition. In enhanced activity of Na+-Ca2+x, single myocyte produces AP duration (APD90) and APD50 is significantly smaller (266 ms and 235 ms). Its Na+-Ca2+x current at depolarization is increases 60% from its normal level and repolarization current goes more negative (nonfailing= -0.28 pA/pF and failing= -0.47 pA/pF). Similarly, same enhanced activity of Na+-Ca2+x in 10 mm region of ventricular sheet, raises the plateau potential abruptly, which ultimately affects the diastolic repolarization. Compare with normal ventricular sheet region of 10 mm, 10% of ventricular sheet resting state is reduces and ventricular sheet at time 250 ms is goes to resting state very early. In hypertrophy condition, single myocyte produces APD90 and APD50 is worthy of attention smaller (232 mS and 198 ms). Its sodium-potassium (Na+-K+) pump current is 75% reduces from its control conditions (0.13 pA/pF). Hypertrophy condition, 50% of ventricular sheet is reduces to minimum plateau potential state, that starts the repolarization process very early and reduces the APD. In a single failing SR Ca2+ channels myocyte, recovery of Ca2+ concentration level in SR reduces upto 15% from its control myocytes. At time 290 ms, 70% of ventricular sheet

Steam generation: fossil-fired systems: utility boilers; industrial boilers; boiler auxillaries; nuclear systems: boiling water; pressurized water; in-core fuel management; steam-cycle systems: condensate/feedwater; circulating water; water treatment

International Nuclear Information System (INIS)

Anon.

1982-01-01

A survey of development in steam generation is presented. First, fossil-fired systems are described. Progress in the design of utility and industrial boilers as well as in boiler auxiliaries is traced. Improvements in coal pulverizers, burners that cut pollution and improve efficiency, fans, air heaters and economisers are noted. Nuclear systems are then described, including the BWR and PWR reactors, in-core fuel management techniques are described. Finally, steam-cycle systems for fossil-fired and nuclear power plants are reviewed. Condensate/feedwater systems, circulating water systems, cooling towers, and water treatment systems are discussed

Synchronous intra-myocardial ventricular pacing without crossing the tricuspid valve or entering the coronary sinus

Energy Technology Data Exchange (ETDEWEB)

Konecny, Tomas; DeSimone, Christopher V.; Friedman, Paul A.; Bruce, Charles [Department of Medicine, Cardiovascular Diseases, Mayo Clinic, Rochester, MN (United States); Asirvatham, Samuel J., E-mail: asirvatham.samuel@mayo.edu [Department of Medicine, Cardiovascular Diseases, Mayo Clinic, Rochester, MN (United States); Department of Pediatric and Adolescent Medicine, Pediatric Cardiology, Mayo Clinic, Rochester, MN (United States)

2013-05-15

Ventricular pacing is most commonly performed at the right ventricular (RV) apex. This is not without risk as placement requires crossing the tricuspid valve (TV) and may cause valvular dysfunction and dyssynchronous activation of the ventricles. The fact that the tricuspid valve lies more apically than the mitral valve allows for the possibility of pacing the ventricles from the right atrium (RA) via the “atrio-ventricular septum” without crossing the TV or entering the coronary sinus (CS). In order to mitigate far field activation inherent to current pacing technology, we constructed a novel lead in which the cathode and anode are both intra-myocardial. We demonstrate safety and efficacy of this novel lead for ventricular pacing at the atrio-ventricular septum in canines, including improved synchronous activation of both ventricles, improved differentiation in ventricular versus atrial sensing, while providing reliable ventricular capture, opening novel and a potentially safer alternative to human cardiac resynchronization therapy.

Left ventricular heart failure and pulmonary hypertension†

Science.gov (United States)

Rosenkranz, Stephan; Gibbs, J. Simon R.; Wachter, Rolf; De Marco, Teresa; Vonk-Noordegraaf, Anton; Vachiéry, Jean-Luc

2016-01-01

Abstract In patients with left ventricular heart failure (HF), the development of pulmonary hypertension (PH) and right ventricular (RV) dysfunction are frequent and have important impact on disease progression, morbidity, and mortality, and therefore warrant clinical attention. Pulmonary hypertension related to left heart disease (LHD) by far represents the most common form of PH, accounting for 65–80% of cases. The proper distinction between pulmonary arterial hypertension and PH-LHD may be challenging, yet it has direct therapeutic consequences. Despite recent advances in the pathophysiological understanding and clinical assessment, and adjustments in the haemodynamic definitions and classification of PH-LHD, the haemodynamic interrelations in combined post- and pre-capillary PH are complex, definitions and prognostic significance of haemodynamic variables characterizing the degree of pre-capillary PH in LHD remain suboptimal, and there are currently no evidence-based recommendations for the management of PH-LHD. Here, we highlight the prevalence and significance of PH and RV dysfunction in patients with both HF with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF), and provide insights into the complex pathophysiology of cardiopulmonary interaction in LHD, which may lead to the evolution from a ‘left ventricular phenotype’ to a ‘right ventricular phenotype’ across the natural history of HF. Furthermore, we propose to better define the individual phenotype of PH by integrating the clinical context, non-invasive assessment, and invasive haemodynamic variables in a structured diagnostic work-up. Finally, we challenge current definitions and diagnostic short falls, and discuss gaps in evidence, therapeutic options and the necessity for future developments in this context. PMID:26508169

Carolee Schneemann. El cine como autobiografía, la artista como actriz, el cuerpo como pincel

Directory of Open Access Journals (Sweden)

María Barbaño González-Moreno

2017-10-01

Full Text Available Este trabajo analiza la relación de cine y mujer a partir de la obra fílmica de Carolee Schneemann, principalmente de su obra autobiográfica Fuses (1964-1966. Desde ella, se plantea el papel de la artista como productora, directora y protagonista principal de todas sus obras. Reflexionamos así sobre el rol del creador-director como actor que derivaría en la consecución de una obra cinematográfica de tintes necesariamente autobiográficos. Asumiendo la visión vanguardista del cine como diario personal/Entendido el cine como diario personal, Schneemann va a explorar en su obra diferentes aspectos de la identidad y la sexualidad de la mujer en un cine artístico, alternativo y de tendencia política feminista. Entendido/Asumido su cine como elemento plástico, la artista explorará de forma paralela la experimentación matérica y física a través de los cuerpos filmados así como de la propia materialidad de la película, excluyendo toda posibilidad narrativa, dramática e ilusoria de proyección del espectador en el espacio cinematográfico y el espacio privado del creador.

Calculation of cardiac pressures using left ventricular ejection fraction (LVEF) derived from radionuclide angiography

International Nuclear Information System (INIS)

Hommer, E.

1981-01-01

An attempt has been made to develop formulas to determine cardiac pressures in an undisturbed flow in patients without valvular or shunt diseases. These are based entirely on the results of left ventricular ejection fraction rates, permitting pressure analysis of several compartments at the same tine. According to BORER et al. they also enable determination of left ventricular 'Functional Reserve' after bycycle exercise as well as left ventricular 'Relaxation Reserve'. They support the views of NYHA in determining the grades of cardiac insufficiency proving the system- and low-pressure participation. A single formula for pulmonary flow can determine the pulmonary arterial pressure. The left ventricular enddiastolic pressure can also be exclusively calculated by values of left ventricular functions, thus both formulas may be used in disorders of the mitral valves. The possibility to calculate pressures of all the compartments of the heart from left ventricular ejection rate shows, that in undisturbed flow global heart function depends on left ventricular function. Therefore the mutual dependence of these formulas presents an intercompartimental pressure regulation of the heart through pulmonary flow and pulmonary vascular pressure, which leaves an aspect of autonomous cardiac regulation open to discussion. (orig.) [de

Diclofenac prolongs repolarization in ventricular muscle with impaired repolarization reserve.

Directory of Open Access Journals (Sweden)

Attila Kristóf

Full Text Available BACKGROUND: The aim of the present work was to characterize the electrophysiological effects of the non-steroidal anti-inflammatory drug diclofenac and to study the possible proarrhythmic potency of the drug in ventricular muscle. METHODS: Ion currents were recorded using voltage clamp technique in canine single ventricular cells and action potentials were obtained from canine ventricular preparations using microelectrodes. The proarrhythmic potency of the drug was investigated in an anaesthetized rabbit proarrhythmia model. RESULTS: Action potentials were slightly lengthened in ventricular muscle but were shortened in Purkinje fibers by diclofenac (20 µM. The maximum upstroke velocity was decreased in both preparations. Larger repolarization prolongation was observed when repolarization reserve was impaired by previous BaCl(2 application. Diclofenac (3 mg/kg did not prolong while dofetilide (25 µg/kg significantly lengthened the QT(c interval in anaesthetized rabbits. The addition of diclofenac following reduction of repolarization reserve by dofetilide further prolonged QT(c. Diclofenac alone did not induce Torsades de Pointes ventricular tachycardia (TdP while TdP incidence following dofetilide was 20%. However, the combination of diclofenac and dofetilide significantly increased TdP incidence (62%. In single ventricular cells diclofenac (30 µM decreased the amplitude of rapid (I(Kr and slow (I(Ks delayed rectifier currents thereby attenuating repolarization reserve. L-type calcium current (I(Ca was slightly diminished, but the transient outward (I(to and inward rectifier (I(K1 potassium currents were not influenced. CONCLUSIONS: Diclofenac at therapeutic concentrations and even at high dose does not prolong repolarization markedly and does not increase the risk of arrhythmia in normal heart. However, high dose diclofenac treatment may lengthen repolarization and enhance proarrhythmic risk in hearts with reduced repolarization reserve.

Reversible left ventricular dysfunction - important clinical problem of contemporary cardiology

International Nuclear Information System (INIS)

Witkowski, A.

1994-01-01

An important clinical issue there is determination whether left ventricular damages are reversible or not single photon emission computed tomography and positron computed tomography techniques are shown to provide valuable data in this problem. Article describes basic syndromes connected with left ventricular dysfunction, namely: hibernating myocardium, stunned myocardium and ischemic myocardium preconditioning. (author). 18 refs

Quantification of cost of margin associated with in-core nuclear fuel management for a PWR

International Nuclear Information System (INIS)

Kropaczek, D.J.; Turinsky, P.J.

1989-01-01

The problem of in-core nuclear fuel management optimization is discussed. The problem is to determine the location of core material, such as the fuel and burnable poisons, so as to minimize (maximize) a stated objective within engineering constraints. Typical objectives include maximization of cycle energy production or discharged fuel exposure, and minimization of power peaking factor or reactor vessel fluence. Constraints include discharge burnup limits and one or more of the possible objectives if not selected as the objective. The optimization problem can be characterized as a large combinatorial problem with nonlinear objective function and constraints, which are likely to be active. The authors have elected to employ the integer Monte Carlo programming method to address this optimization problem because of the just-noted problem characteristics. To evaluate the core physics characteristics as a function of fuel loading pattern, second-order accurate perturbation theory is employed with successive application to improve estimates of the optimum loading pattern. No constraints on fuel movement other than requiring quarter-core symmetry were imposed. In this paper the authors employed this methodology to address a related problem. The problem being addressed can be stated as What is the cost associated with margin? Specifically, they wish to assign some financial value in terms of increased levelized fuel cycle cost associated with an increase in core margin of some type, such as power peaking factor

Subclinical changes in MRI-determined right ventricular volumes and function in subjects with prediabetes and diabetes.

Science.gov (United States)

Patscheider, Hannah; Lorbeer, Roberto; Auweter, Sigrid; Schafnitzel, Anina; Bayerl, Christian; Curta, Adrian; Rathmann, Wolfgang; Heier, Margit; Meisinger, Christa; Peters, Annette; Bamberg, Fabian; Hetterich, Holger

2018-07-01

The aim of this study was to assess subclinical changes in right ventricular volumes and function in subjects with prediabetes and diabetes and controls without a history of cardiovascular disease. Data from 400 participants in the KORA FF4 study without self-reported cardiovascular disease who underwent 3-T whole-body MRI were obtained. The right ventricle was evaluated using the short axis and a four-chamber view. Diabetes was defined according to WHO criteria. Associations between glucose tolerance and right ventricular parameters were assessed using multivariable adjusted linear regression models. Data from 337 participants were available for analysis. Of these, 43 (13%) had diabetes, 87 (26%) had prediabetes, and 207 (61%) were normoglycaemic controls. There was a stepwise decrease in right ventricular volumes in men with prediabetes and diabetes in comparison with controls, including right ventricular end-diastolic volume (β = -20.4 and β = -25.6, respectively; p ≤ 0.005), right ventricular end-systolic volume (β = -12.3 and β = -12.7, respectively; p ≤ 0.037) and right ventricular stroke volume (β = -8.1 and β = -13.1, respectively, p ≤ 0.016). We did not observe any association between prediabetes or diabetes and right ventricular volumes in women or between prediabetes or diabetes and right ventricular ejection fraction in men and women. This study points towards early subclinical changes in right ventricular volumes in men with diabetes and prediabetes. • MRI was used to detect subclinical changes in right ventricular parameters. • Diabetes mellitus is associated with right ventricular dysfunction. • Impairment of right ventricular volumes seems to occur predominantly in men.

Assessment of right ventricular afterload in mitral valve diseases with radionuclide angiography

International Nuclear Information System (INIS)

Shimizu, Mitsuharu; Nakagawa, Tomio; Kohno, Yoshihiro; Kuroda, Masahiro; Takeda, Yoshihiro; Hiraki, Yoshio; Nagaya, Isao; Senoh, Yoshimasa; Teramoto, Shigeru

1991-01-01

Right ventricular function at rest and during exercise was studied in 33 patients with mitral valve disease by equilibrium gated radionuclide angiography using 99m Tc in vivo labeled red blood cells. Radionuclide measurements of right ventricular ejection fraction (RVEF) were correlated with mean pulmonary arterial pressure (mPAP). RVEF decreased significantly with exercise. There was no significant correlation between RVEF at rest and mPAP. However, mPAP showed significant negative correlation with RVEF during exercise and with the changes of RVEF from rest to exercise. It is concluded that RVEF during exercise in mitral valve disease is affected by right ventricular afterload, and the measurements of RVEF at rest and during exercise by equilibrium gated radionuclide angiography is useful to assess right ventricular afterload. (author)

His-Purkinje system-related incessant ventricular tachycardia arising from the left coronary cusp

Directory of Open Access Journals (Sweden)

Eiji Sato, MD

2014-08-01

Full Text Available We describe the case of a 23-year-old woman who had His-Purkinje system-related incessant ventricular tachycardia with a narrow QRS configuration. The ventricular tachycardia was ablated successfully in the left coronary cusp where the earliest endocardial activation had been recorded. We hypothesize that a remnant of the subaortic conducting tissue was the source of the ventricular arrhythmias.

Ventricular function during the acute rejection of heterotopic transplanted heart: Gated blood pool studies

International Nuclear Information System (INIS)

Valette, H.; Bourguignon, M.H.; Desruennes, M.; Merlet, P.; Le Guludec, D.; Syrota, A.

1991-01-01

Twenty patients who had undergone a heterotopic heart transplant were studied prospectively to determine the relationship between rejection and ventricular dysfunction assessed from gated blood pool studies. A fully automated method for detecting ventricular edges was implemented; its success rate for the grafted left and right ventricles was 94% and 77%, respectively. The parameters, peak ejection and filling rates, were calculated pixel per pixel using a two-harmonic Fourier algorithm and then averaged over the ventricular region of interest. Peak filling and ejection rates were closely related with the severity of the rejection, while the left ventricular ejection fraction was not. Peak filling rates of both ventricles were the indices closely related to the presence of moderate rejection. Despite the low number of patients, these data suggested that gated blood pool derived indices of ventricular function are associated with ventricular dysfunction resulting from myocarditis rejection. Radionuclide ventriculography provides parametric data which are accurate and reliable for the diagnosis of rejection. (orig.)

EVALUACIÓN ECOCARDIOGRÁFICA DE LA FUNCIÓN VENTRICULAR IZQUIERDA EN CENTENARIOS / Echocardiographic assessment of left ventricular function in centenarians

Directory of Open Access Journals (Sweden)

Vanessa Peña-Bofill

2013-10-01

Full Text Available Resumen Introducción: El envejecimiento poblacional es un fenómeno mundial y constituye un logro de la humanidad. Objetivo: Caracterizar ecocardiográficamente la función ventricular izquierda de pacientes ambulatorios mayores de 100 años del municipio Plaza de la Revolución, en el período de septiembre del 2009 a septiembre del 2010. Método: Se realizó un estudio descriptivo de corte transversal con 20 longevos, en el Departamento de Ecocardiografía del Hospital Universitario "General Calixto García", a los cuáles se les realizó ecocardiograma para evaluar la función ventricular izquierda. Resultados: La edad media fue de 102 años, predominó el sexo femenino con 15 pacientes (75 % y el 50 % tenía color de piel blanco. El factor de riesgo coronario de mayor prevalencia fue la hipertensión arterial (40 %; la diabetes mellitus tipo 2, el tabaquismo y la dislipidemia le sucedieron en orden. Los centenarios tenían conservada la función sistólica del ventrículo izquierdo (90 % con poca tendencia a la supernormalidad, una paciente presentó trastornos segmentarios de la contractilidad en cara inferior, lo que correspondía a antecedentes de infarto de miocardio. Cuatro centenarios tenían patrón de llenado normal, 11 presentaron alteración de la relajación ventricular y cinco patrones pseudonormales. Conclusiones: En los centenarios estudiados se mantiene una función sistólica del ventrículo izquierdo evaluada por ecocardiografía, dentro de parámetros normales, con signos de disfunción diastólica leve. / Abstract Introduction: Population aging is a global phenomenon and an achievement of mankind. Objective: To characterize left ventricular function by echocardiography in ambulatory patients over 100 years old in Plaza de la Revolution Municipality, between September 2009 and September 2010. Method: A descriptive cross-sectional study was carried out with 20 long-lived people, in the Department of Echocardiography of

10-year follow-up after radiofrequency ablation of idiopathic ventricular arrhythmias from right ventricular outflow tract

Directory of Open Access Journals (Sweden)

Synne Dragesund Rørvik

2016-05-01

Conclusions: A reduction of symptoms and use of antiarrhythmic medication, as well as an improvement in the general health perception and fitness to work after RFA of idiopathic ventricular arrhythmias can be demonstrated at ten-year follow-up.

Normalised radionuclide measures of left ventricular diastolic function

International Nuclear Information System (INIS)

Lee, K.J.; Southee, A.E.; Bautovich, G.J.; Freedman, B.; McLaughlin, A.F.; Rossleigh, M.A.; Hutton, B.F.; Morris, J.G.; Royal Prince Alfred Hospital, Sydney

1989-01-01

Abnormal left ventricular diastolic function is being increasingly recognised in patients with clinical heart failure and normal systolic function. A simple routine radionuclide measure of diastolic function would therefore be useful. To establish, the relationship of peak diastolic filling rate (normalized for either end diastolic volume, stroke volume, or peak systolic emptying rate), and heart rate, age, and left ventricular ejection fraction was studied in 64 subjects with normal cardiovascular systems using routine gated heart pool studies. The peak filling rate when normalized to end diastolic volume correlated significantly with heart rate, age and left ventricular ejection fraction, whereas normalization to stroke volume correlated significantly to heart rate and age but not to left ventricular ejection fraction. Peak filling rate normalized for peak systolic emptying rate correlated with age only. Multiple regression equations were determined for each of the normalized peak filling rates in order to establish normal ranges for each parameter. When using peak filling rate normalized for end diastolic volume or stroke volume, appropriate allowance must be made for heart rate, age and ejection fraction. Peak filling rate normalized to peak ejection rate is a heart rate independent parameter which allows the performance of the patient's ventricle in diastole to be compared with its systolic function. It may be used in patients with normal systolic function to serially follow diastolic function, or if age corrected to screen for diastolic dysfunction. (orig.)

Pneumatic distension of ventricular mural architecture validated histologically

International Nuclear Information System (INIS)

Burg, M.C.; Heindel, W.; Lunkenheimer, P.; Niederer, P.; Brune, C.; Redmann, K.; Smerup, M.; Spiegel, U.; Becker, F.; Maintz, D.; Cologne Univ.; Anderson, R.H.

2016-01-01

There are ongoing arguments as to how cardiomyocytes are aggregated together within the ventricular walls. We used pneumatic distension through the coronary arteries to exaggerate the gaps between the aggregated cardiomyocytes, analyzing the pattern revealed using computed tomography, and validating our findings by histology. We distended 10 porcine hearts, arresting 4 in diastole by infusion of cardioplegic solutions, and 4 in systole by injection of barium chloride. Mural architecture was revealed by computed tomography, measuring also the angulations of the long chains of cardiomyocytes. We prepared the remaining 2 hearts for histology by perfusion with formaldehyde. Increasing pressures of pneumatic distension elongated the ventricular walls, but produced insignificant changes in mural thickness. The distension exaggerated the spaces between the aggregated cardiomyocytes, compartmenting the walls into epicardial, central, and endocardial regions, with a feathered arrangement of transitions between them. Marked variation was noted in the thicknesses of the parts in the different ventricular segments, with no visible anatomical boundaries between them. Measurements of angulations revealed intruding and extruding populations of cardiomyocytes that deviated from a surface-parallel alignment. Scrolling through the stacks of tomographic images revealed marked spiraling of the aggregated cardiomyocytes when traced from base to apex. Our findings call into question the current assumption that cardiomyocytes are uniformly aggregated together in a tangential fashion. There is marked heterogeneity in the architecture of the different ventricular segments, with the aggregated units never extending in a fully transmural fashion.

Pneumatic distension of ventricular mural architecture validated histologically

Energy Technology Data Exchange (ETDEWEB)

Burg, M.C.; Heindel, W. [University Hospital Muenster (Germany). Dept. of Clinical Radiology; Lunkenheimer, P. [University Hospital Muenster (Germany). Dept. of Experimental Thoraco-vascular Surgery; Niederer, P. [ETH and University of Zuerich (Switzerland). Inst. for Biomedical Engineering; Brune, C. [Twente Univ. (Netherlands). Dept. of Applied Mathematics; Redmann, K. [University Hospital Muenster (Germany). Center for Reproductive Medicine and Andrology; Smerup, M. [Aarhus University Hospital (Denmark). Dept. of Cardiothoracic and Vascular Surgery; Spiegel, U.; Becker, F. [University Hospital Muenster (Germany). Dept. Surgical Research; Maintz, D. [University Hospital Muenster (Germany). Dept. of Clinical Radiology; Cologne Univ. (Germany). Dept. of Radiology; Anderson, R.H. [Newcastle Univ., London (United Kingdom). Inst. of Genetic Medicine

2016-11-15

There are ongoing arguments as to how cardiomyocytes are aggregated together within the ventricular walls. We used pneumatic distension through the coronary arteries to exaggerate the gaps between the aggregated cardiomyocytes, analyzing the pattern revealed using computed tomography, and validating our findings by histology. We distended 10 porcine hearts, arresting 4 in diastole by infusion of cardioplegic solutions, and 4 in systole by injection of barium chloride. Mural architecture was revealed by computed tomography, measuring also the angulations of the long chains of cardiomyocytes. We prepared the remaining 2 hearts for histology by perfusion with formaldehyde. Increasing pressures of pneumatic distension elongated the ventricular walls, but produced insignificant changes in mural thickness. The distension exaggerated the spaces between the aggregated cardiomyocytes, compartmenting the walls into epicardial, central, and endocardial regions, with a feathered arrangement of transitions between them. Marked variation was noted in the thicknesses of the parts in the different ventricular segments, with no visible anatomical boundaries between them. Measurements of angulations revealed intruding and extruding populations of cardiomyocytes that deviated from a surface-parallel alignment. Scrolling through the stacks of tomographic images revealed marked spiraling of the aggregated cardiomyocytes when traced from base to apex. Our findings call into question the current assumption that cardiomyocytes are uniformly aggregated together in a tangential fashion. There is marked heterogeneity in the architecture of the different ventricular segments, with the aggregated units never extending in a fully transmural fashion.

Relationship between obesity and left ventricular hypertrophy in children

Directory of Open Access Journals (Sweden)

Johnny Rompis

2016-10-01

Full Text Available Background Obesity is a chronic metabolic disorder associated with cardiovascular disease (CVD increasing morbidity-mortality rates. It is apparent that a variety of adaptations/alterations in cardiac structure and function occurs as excessive adipose tissue accumulates. This leads to a decrease in diastolic compliance, eventually resulting in an increase in left ventricular filling pressure and left ventricular enlargement. Objective To evaluate left ventricular hypertrophy (LVH among  obese using electrocardiographic (ECG criteria. Methods A cross-sectional study was conducted on 74 children aged 10-15 years from February 2009 to October 2009. The subjects were divided into obese and control groups. Physical examination and standard 12 lead electrocardiography (ECG were done in both groups. Results Of 37 obese children, LVH were featured in 3 subjects, while in control group, only 1 child had LVH (P= 0.304. We found that mean RV6 in obese and control group were 9.8446 (SD 3.5854 and 11.9662 (SD 3.2857, respectively (P=0.005. As an additional findings, we found that birth weight was related to obesity in children. Conclusion There is no relation between obesity and left ventricular using ECG criteria in obese children aged 10-15 years.

Biopróteses de pericárdio bovino Fisics-Incor: 15 anos

Directory of Open Access Journals (Sweden)

POMERANTZEFF Pablo M. A.

1997-01-01

Full Text Available No período de março de 1982 a dezembro de 1995 foram implantadas biopróteses de pericárdio bovino Fisics-Incor em 2259 pacientes. A média de idade foi de 47,2 ± 17,5 anos e 55% eram do sexo masculino. A principal etiologia das lesões foi a febre reumática em 1031 (45,7% pacientes. Foram realizadas 1073 substituições da valva aórtica, 1085 mitral, 195 mitro-aórtica, 27 tricúspide e 16 substituições combinadas. Cirurgias associadas foram realizadas em 788 (32,9% pacientes, predominando a plástica da valva tricúspide (9,2% e a revascularização do miocárdio (7,7%. A mortalidade hospitalar global foi de 194 (8,6% pacientes, 8,6% na substituição mitral isolada, 4,7% na aórtica e 12,8% na mitro-aórtica. As taxas linearizadas para os eventos calcificação, tromboembolismo, rotura, escape e endocardite são, respectivamente: 1,1%; 0,2%; 0,9%; 0,1% e 0,5% pacientes/ano. A curva actuarial de sobrevida é de 56,7% ± 5,4% em 15 anos. Livre de endocardite foi de 91,9% ± 2%, livre de tromboembolismo de 95 ± 1,7%, livre de rotura de 43,7 ± 19,8%, livre de escape 98,9 ± 4,5% e livre de calcificação de 48,8 ± 7,9% em 15 anos. No pós-operatório tardio 1614 (80,6% pacientes encontram-se em classe funcional I (NYHA. Podemos concluir que os pacientes submetidos a implante de biopróteses de pericárdio bovino apresentaram evolução satisfatória.

Effect of in-core instrumentation mounting location on external reactor vessel cooling

International Nuclear Information System (INIS)

Suh, Jungsoo; Ha, Huiun

2017-01-01

Highlights: • Numerical simulations were conducted for the evaluation of an IVR-ERVC application. • The ULPU-V experiment was simulated for the validation of numerical method. • The effect of ICI mounting location on an IVR-ERVC application was investigated. • TM-ICI is founded to be superior to BM-ICI for successful application of IVR-ERVC. - Abstract: The effect of in-core instrumentation (ICI) mounting location on the application of in-vessel corium retention through external reactor vessel cooling (IVR-ERVC), used to mitigate severe accidents in which the nuclear fuel inside the reactor vessel becomes molten, was investigated. Numerical simulations of the subcooled boiling flow within an advanced pressurized-water reactor (PWR) in IVR-ERVC applications were conducted for the cases of top-mounted ICI (TM-ICI) and bottom-mounted ICI (BM-ICI), using the commercially available computational fluid dynamics (CFD) software ANSYS-CFX. Shear stress transport (SST) and the RPI model were used for turbulence closure and subcooled flow boiling, respectively. To validate the numerical method for IVR applications, numerical simulations of ULPU-V experiments were also conducted. The BM-ICI reactor vessel was modeled using a simplified design of an advanced PWR with BM-ICI; the TM-ICI counterpart was modeled by removing the ICI parts from the original geometry. It was found that TM-ICI was superior to BM-ICI for successful application of IVR-ERVC. For the BM-ICI case, the flow field was complicated because of the existence of ICIs and a significant temperature gradient was observed near the ICI nozzles on the lower part of the reactor vessel, where the ICIs were attached. These observations suggest that the existence of ICI below the reactor vessel hinders reactor vessel cooling.

Comparison of right ventricular septal pacing and right ventricular apical pacing in patients receiving cardiac resynchronization therapy defibrillators: the SEPTAL CRT Study

Science.gov (United States)

Leclercq, Christophe; Sadoul, Nicolas; Mont, Lluis; Defaye, Pascal; Osca, Joaquim; Mouton, Elisabeth; Isnard, Richard; Habib, Gilbert; Zamorano, Jose; Derumeaux, Genevieve; Fernandez-Lozano, Ignacio; Dupuis, Jean-Marc; Rouleau, Frédéric; Tassin, Aude; Bordachar, Pierre; Clémenty, Jacques; Lafitte, Stephane; Ploux, Sylvan; Reant, Patricia; Ritter, Philippe; Defaye, Pascal; Jacon, Peggy; Mondesert, Blandine; Saunier, Carole; Vautrin, Estelle; Kacet, Salem; Guedon-Moreau, Laurence; Klug, Didier; Kouakam, Claude; Marechaux, Sylvestre; Marquie, Christelle; Polge, Anne Sophie; Richardson, Marjorie; Chevallier, Philippe; De Breyne, Brigitte; Lotek, Marcin M.; Nonin, Emilie; Pineau, Julien; Deharo, Jean-Claude; Bastard, Emilie; Franceschi, Frédéric; Habib, Gilbert; Jego, Christophe; Peyrouse, Eric; Prevot, Sebastien; Saint-Joseph, Hôpital; Bremondy, Michel; Faure, Jacques; Ferracci, Ange; Lefevre, Jean; Pisapia, Andre; Davy, Jean-Marc; Cransac, Frederic; Cung, Tien Tri; Georger, Frederic; Pasquie, Jean-Luc; Raczka, Franck; Sportouch-Dukhan, Catherine; Sadoul, Nicolas; Blangy, Hugues; Bruntz, Jean-François; Freysz, Luc; Groben, Laurent; Huttin, Olivier; Bammert, Antoine; Burban, Marc; Cebron, Jean-Pierre; Gras, Daniel; Frank, Robert; Duthoit, Guillaume; Hidden-Lucet, Françoise; Himbert, Caroline; Isnard, Richard; Lacotte, Jérôme; Pousset, Françoise; Zerah, Thierry; Leclercq, Christophe; Bellouin, Annaïk; Crocq, Christophe; Deplace, Christian; Donal, Erwan; Hamon, Cécile; Mabo, Philippe; Romain, Olivier; Solnon, Aude; Frederic, Anselme; Bauer, Fabrice; Bernard, Mathieu; Godin, Benedicte; Kurtz, Baptiste; Savoure, Arnaud; Copie, Xavier; Lascault, Gilles; Paziaud, Olivier; Piot, Olivier; Touche, Thierry; Delay, Toulouse Marc; Chilon, Talia; Detis, Nicolas; Duparc, Alexandre; Hebrard, Aurélien; Massabuau, Pierre; Maury, Philippe; Mondoly, Pierre; Rumeau, Philippe; Pasteur, Clinique; Boveda, Serge; Adrover, Laurence; Combes, Nicolas; Deplagne, Antoine; Marco-Baertich, Isabelle; Fondard, Olivier; Martínez, Juan Gabriel; Ibañez Criado, José Luis; Ortuño, Diego; Mont, Lluis; Berruezo, Antonio; Eduard, Belu; Martín, Ana; Merschon, Franco M.; Sitges, Marta; Tolosana, José María; Vidal, Bárbara; Hebron, H. Valle; i Mitjans, Angel Moya; Rodriguez, Oscar Alcalde; Rodriguez Palomares, José Fernando; Rivas, Nuria; Teixidó, Gisela; de Hierro, H. Puerta; Lozano, Ignacio Fernández; Ruiz Bautista, Maria Lorena; Castro, Victor; Cavero, Miguel Angel; Gutierrez, Carlos; Ros, Natalia; de la Victoria, H. Virgen; Alzueta Rodriguez, Francisco Javier; Cabrera, Fernando; Cordero, Alberto Barrera; Peña, José Luis; de Valme Sevilla, H.; Gonzáles, Juan Lealdel Ojo; Garcia Medina, Mª Dolores; Jiménez, Ricardo Pavón; Villagomez, David; de la Salud Toledo, H. Virgen; Castellanos Martinez, Eduardo; Alcalá, Juan; Maicas, Carolina; Arias Palomares, Miguel Angel; Puchol, Alberto; Valencia, H. La Fé; OscaAsensi, Joaquim; Carmona, Anastasio Quesada; De Carranza, Mª José Sancho-Tello; De Ros, José Olagüe; Pareja, Enrique Castro; Pérez, Oscar Cano; Saez, Ana Osa; Hortega, H. Rio; Guilarte, Benito Herreros; Muñoz San Jose, Juan Francisco; Pérez Sanz, Teresa Myriam; Logeart, Damien; Gil, Maria Lopez; Leclercq, Christophe; Lozano, Ignacio Fernandez; de Hierro, H. Puerta; Derumeaux, Genevieve

2016-01-01

Abstract Aims Cardiac resynchronization therapy (CRT) is a recommended treatment of heart failure (HF) patients with depressed left ventricular ejection fraction and wide QRS. The optimal right ventricular (RV) lead position being a matter of debate, we sought to examine whether RV septal (RVS) pacing was not inferior to RV apical (RVA) pacing on left ventricular reverse remodelling in patients receiving a CRT-defibrillator. Methods and results Patients (n = 263, age = 63.4 ± 9.5 years) were randomly assigned in a 1:1 ratio to RVS (n = 131) vs. RVA (n = 132) pacing. Left ventricular end-systolic volume (LVESV) reduction between baseline and 6 months was not different between the two groups (−25.3 ± 39.4 mL in RVS group vs. −29.3 ± 44.5 mL in RVA group, P = 0.79). Right ventricular septal pacing was not non-inferior (primary endpoint) to RVA pacing with regard to LVESV reduction (average difference = −4.06 mL; P = 0.006 with a −20 mL non-inferiority margin). The percentage of ‘echo-responders’ defined by LVESV reduction >15% between baseline and 6 months was similar in both groups (50%) with no difference in the time to first HF hospitalization or death (P = 0.532). Procedural or device-related serious adverse events occurred in 68 patients (RVS = 37) with no difference between the two groups (P = 0.401). Conclusion This study demonstrates that septal RV pacing in CRT is non-inferior to apical RV pacing for LV reverse remodelling at 6 months with no difference in the clinical outcome. No recommendation for optimal RV lead position can hence be drawn from this study. ClinicalTrials. gov number NCT 00833352. PMID:26374852

Hypertension and left ventricular hypertrophy in liquidators of consequences of the Chernobyl nuclear accident

International Nuclear Information System (INIS)

Shal'nova, S.A.; Smolenskij, A.V.; Shamarin, V.M.; Ehktova, T.V.; Berzak, N.V.; Zemtsova, N.A.; Timofeeva, S.G.; Zhavoronkova, E.A.; Muromtseva, G.A.; Arkad'eva, M.A.; Deev, A.D.

1998-01-01

Echocardiography was used for the study of prevalence of left ventricular hypertrophy in 839 liquidators of consequences of the Chernobyl accident. Prevalence of left ventricular hypertrophy (left ventricular myocardial mass 134 g/m 2 ) was 10.3, 13.4 and 22.5 % in liquidators with normal blood pressure, borderline hypertension and hypertension, respectively. Liquidators with normal blood pressure had significantly greater left ventricular myocardial mass than normotensive men from general population while liquidators and non liquidators with hypertension had equal values of this parameter [ru

[Ventricular tachyarrhythmias in patients with cardiomyopathy

DEFF Research Database (Denmark)

Henningsen, K.; Christensen, A.H.; Svendsen, Jesper Hastrup

2008-01-01

by disease, gender, age, previous cardiac arrest and treatment with implantable cardioverter-defibrillator (ICD). RESULTS: 993 patients were screened and 128 patients with cardiomyopathy were identified, corresponding to 13% of the screened patients. 58 (45%) of the patients had dilated cardiomyopathy (DCM......), 57 (45%) patients had arrhythmogenic right ventricular cardiomyopathy (ARVC) and 13 (10%) had hypertrophic cardiomyopathy (HCM). The average age was 44 years for HCM, 41 years for ARVC and 58 years for DCM. The majority of the patients were male. ICD treatment was used in 95% of the patients...... with ARVC, 70% of the patients with HCM and 59% of the patients with DCM. Only 5 patients had previous cardiac arrest without reversible cause. CONCLUSION: The study shows that cardiomyopathies are relatively frequent causes of ventricular tachyarrhythmias in patients discharged from a specialised...

Effects of AV delay programming on ventricular resynchronisation: role of radionuclide ventriculography

Energy Technology Data Exchange (ETDEWEB)

Siegrist, Patrick T.; Comte, Nathalie; Holzmeister, Johannes; Suetsch, Gabor; Koepfli, Pascal; Namdar, Mehdi; Duru, Firat; Brunckhorst, Corinna; Scharf, Christoph [Universitiy Hospital Zurich NUK C 32, Cardiovascular Center, Zurich (Switzerland); Kaufmann, Philipp A. [Universitiy Hospital Zurich NUK C 32, Cardiovascular Center, Zurich (Switzerland); University of Zurich, Zurich Center for Integrative Human Physiology, Zurich (Switzerland)

2008-08-15

Optimal atrioventricular delay (AVD) setting for cardiac resynchronisation therapy, i.e. biventricular pacing in patients with heart failure, remains a formidable challenge. Thus, the purpose of this study was to evaluate the effects of different AVD on inter- and intra-ventricular resynchronisation using phase histograms of radionuclide ventriculography (RNV). In 17 consecutive patients (mean age 64 {+-} 6 years), RNV was performed 236 {+-} 350 days after pacemaker implantation for cardiac resynchronisation therapy. Images were acquired during atrial pacing at 80 bpm and during biventricular pacing with AVD ranging from 80 to 160 ms. Inter-ventricular dyssynchrony was measured by the delay between the mean phase angles of the left and right ventricles. Intra-ventricular dyssynchrony was measured by the standard deviation (SD) of left ventricular phase histograms. Left ventricular (LV) ejection fraction (EF) was inversely correlated to LV dyssynchrony (SD of LV phase histogram, R = -0.82, p < 0.0001). However, the increase in LVEF by biventricular pacing (mean +4.4 {+-} 4%) showed only modest correlation to the resulting resynchronisation effect (characterised by a -13 {+-} 8 decrease in LV phase histogram SD, R = -0.38, p < 0.0001). RNV is helpful in optimising pacing parameters for resynchronisation therapy. Varying AVD did not have a major impact on intra- or inter-ventricular resynchronisation. Thus, the benefit of AVD-based LVEF optimisation seems to result from atrioventricular resynchronisation. (orig.)

Simultaneous determination of left ventricular perfusion and function