Introdução: Embora o papel da ecocardiografia transesofágica (ETE) esteja bem estabelecido na avaliação morfológica e funcional da valva mitral e na seleção dos pacientes com prolapso da valva mitral (PVM) para a cirurgia reparadora, o impacto da ETE tridimensional (3D) no resultado cirúrgico ainda não está bem demonstrado. Os objetivos deste trabalho foram avaliar o valor diagnóstico adicional da ETE 3D em comparação com a técnica bidimensional (2D) e a associação de parâmetros anatômicos tridimensionais com o resultado cirúrgico em pacientes com PVM submetidos à valvoplastia. Métodos: Para a análise comparativa da sensibilidade, especificidade e acurácia diagnóstica entre ETE 2D e 3D, foram incluídos 62 pacientes operados por PVM com insuficiência importante, sendo a inspeção cirúrgica considerada padrão-ouro. Para a análise 3D, foram estudados 54 pacientes submetidos à plástica valvar que foram divididos em 2 grupos de acordo com o grau da insuficiência mitral pós-operatória (grupo 1, insuficiência mitral ausente ou grau I; grupo 2, insuficiência mitral grau II ou III). Foram medidos pela quantificação 3D os seguintes parâmetros anatômicos: diâmetros anteroposterior e intercomissural, altura, circunferência e área do anel mitral; comprimento, área e linha de coaptação das cúspides; volume e altura do prolapso; distância dos músculos papilares à borda da cúspide; e ângulos mitroaórtico e não planar. Para a identificação de variáveis associadas aos grupos de resultados cirúrgicos, foi realizada análise univariada (teste t de Student para as variáveis contínuas e teste qui-quadrado ou o teste de Fisher para as variáveis categóricas), análise multivariada com método de regressão logística e curva ROC para a obtenção do ponto de corte. Resultados: A ETE 2D apresentou maior sensibilidade no diagnóstico de prolapso nos segmentos A2, P1 e P3 que a ETE 3D (p = 0,019, 0,023, 0,012, respectivamente) enquanto que a ETE 3D apresentou maior especificidade no segmento P1 (p = 0,006). Não houve diferença na acurácia diagnóstica ente os dois métodos. A presença de prolapso das duas cúspides (p = 0,041) e a distância do músculo papilar posteromedial à borda da cúspide (p = 0,038) foram maiores no grupo 2. Análise multivariada identificou prolapso das duas cúspides e distância do músculo papilar posteromedial à borda da cúspide maior que 30 mm como fatores associados à insuficiência mitral pós-operatória grau II ou III (p = 0,039 e 0,015, respectivamente), e com risco de 5,3 e 6,3 vezes maior de insuficiência significativa pós-operatória, respectivamente. Conclusões: A ETE 2D e 3D apresentaram acurácia equivalente no diagnóstico de PVM, com maior sensibilidade da ETE 2D no diagnóstico de prolapso nos segmentos A2, P1 e P3, e maior especificidade da ETE 3D no segmento P1. A distância do músculo papilar posteromedial à borda da cúspide obtida pela análise quantitativa 3D e a presença de prolapso das duas cúspides mostraram associação com o grau da insuficiência mitral pós-operatória grau II e III / Background: Although the transesophageal echocardiography (TEE) is well established in the morphological and functional assessment of the mitral valve and in the choice of patients with mitral valve prolapse (MVP) eligible to valvuloplasty, the impact of tridimensional (3D) TEE on surgical results has not been well demonstrated yet. The present study aimed to evaluate the additional diagnostic value of 3D TEE in comparison with bidimensional (2D) technique, as well as the correlation between 3D anatomical parameters and the surgical results in patients with MVP submitted to valvuloplasty. Methods: In order to compare the sensitivity, specificity, and accuracy between 2D and 3D TEE, 62 patients with MVP and severe mitral regurgitation were enrolled; surgical appraisal was considered as the gold-standard. Regarding 3D analysis, 54 patients submitted to valvuloplasty were divided in two groups, according to their postoperative mitral regurgitation grades (group 1, absent or grade I mitral regurgitation; and group 2, grade II or III mitral regurgitation). The following parameters were assessed quantitatively by 3D TEE: anteroposterior diameter, commissural width, height, circumference and area of the mitral ring; anterior and posterior leaflets length, leaflets surface area, coaptation length, volume and height billow; distance from the tip of the anterolateral and posteromedial papillary muscle to leaflet border; non-planar and aortic-mitral angles. Univariate analysis (Student t test for continuous variables and Chi-square or Fischer test to the categorical ones), multivariate and ROC curve analyses were performed to identify the relationship between anatomical parameters and surgical results (p < 5%). Results: 2D TEE showed higher sensitivity to diagnose MVP in A2, P1, and P3 segments, when compared with 3D TEE (p= 0.019, 0.023, and 0.012, respectively), while 3D TEE showed greater specificity to identify P1 segment (p= 0.006). No difference was observed in the accuracy between both methods. The presence of bileaflet prolapse (p= 0.041) and the distance from posteromedial papillary muscle to leaflet border (p= 0.038) were higher in group 2. Multivariate analysis showed that bileaflet prolapse and distance of more than 30 mm from posteromedial papillary muscle to leaflet border were related to grade II or III postoperative mitral regurgitation (p= 0.039 and 0.015, respectively), representing 5.3 and 6.3 more risk of significant mitral regurgitation, respectively. Conclusions: Both 2D TEE and 3D TEE presented similar accuracy in the diagnosis of MVP; 2D TEE showed higher sensitivity to diagnose the prolapse in A2, P1 and P3 segments, while the 3D TEE presented greater specificity to identify the affected P1 segment. The distance from the tip of the posteromedial papillary muscle to the leaflet border quantitatively estimated by 3D TEE and the evidence of bileaflet prolapse showed to be associated to the degree of mitral regurgitation after valvuloplasty

Introdução: Embora o papel da ecocardiografia transesofágica (ETE) esteja bem estabelecido na avaliação morfológica e funcional da valva mitral e na seleção dos pacientes com prolapso da valva mitral (PVM) para a cirurgia reparadora, o impacto da ETE tridimensional (3D) no resultado cirúrgico ainda não está bem demonstrado. Os objetivos deste trabalho foram avaliar o valor diagnóstico adicional da ETE 3D em comparação com a técnica bidimensional (2D) e a associação de parâmetros anatômicos tridimensionais com o resultado cirúrgico em pacientes com PVM submetidos à valvoplastia. Métodos: Para a análise comparativa da sensibilidade, especificidade e acurácia diagnóstica entre ETE 2D e 3D, foram incluídos 62 pacientes operados por PVM com insuficiência importante, sendo a inspeção cirúrgica considerada padrão-ouro. Para a análise 3D, foram estudados 54 pacientes submetidos à plástica valvar que foram divididos em 2 grupos de acordo com o grau da insuficiência mitral pós-operatória (grupo 1, insuficiência mitral ausente ou grau I; grupo 2, insuficiência mitral grau II ou III). Foram medidos pela quantificação 3D os seguintes parâmetros anatômicos: diâmetros anteroposterior e intercomissural, altura, circunferência e área do anel mitral; comprimento, área e linha de coaptação das cúspides; volume e altura do prolapso; distância dos músculos papilares à borda da cúspide; e ângulos mitroaórtico e não planar. Para a identificação de variáveis associadas aos grupos de resultados cirúrgicos, foi realizada análise univariada (teste t de Student para as variáveis contínuas e teste qui-quadrado ou o teste de Fisher para as variáveis categóricas), análise multivariada com método de regressão logística e curva ROC para a obtenção do ponto de corte. Resultados: A ETE 2D apresentou maior sensibilidade no diagnóstico de prolapso nos segmentos A2, P1 e P3 que a ETE 3D (p = 0,019, 0,023, 0,012, respectivamente) enquanto que a ETE 3D apresentou maior especificidade no segmento P1 (p = 0,006). Não houve diferença na acurácia diagnóstica ente os dois métodos. A presença de prolapso das duas cúspides (p = 0,041) e a distância do músculo papilar posteromedial à borda da cúspide (p = 0,038) foram maiores no grupo 2. Análise multivariada identificou prolapso das duas cúspides e distância do músculo papilar posteromedial à borda da cúspide maior que 30 mm como fatores associados à insuficiência mitral pós-operatória grau II ou III (p = 0,039 e 0,015, respectivamente), e com risco de 5,3 e 6,3 vezes maior de insuficiência significativa pós-operatória, respectivamente. Conclusões: A ETE 2D e 3D apresentaram acurácia equivalente no diagnóstico de PVM, com maior sensibilidade da ETE 2D no diagnóstico de prolapso nos segmentos A2, P1 e P3, e maior especificidade da ETE 3D no segmento P1. A distância do músculo papilar posteromedial à borda da cúspide obtida pela análise quantitativa 3D e a presença de prolapso das duas cúspides mostraram associação com o grau da insuficiência mitral pós-operatória grau II e III / Background: Although the transesophageal echocardiography (TEE) is well established in the morphological and functional assessment of the mitral valve and in the choice of patients with mitral valve prolapse (MVP) eligible to valvuloplasty, the impact of tridimensional (3D) TEE on surgical results has not been well demonstrated yet. The present study aimed to evaluate the additional diagnostic value of 3D TEE in comparison with bidimensional (2D) technique, as well as the correlation between 3D anatomical parameters and the surgical results in patients with MVP submitted to valvuloplasty. Methods: In order to compare the sensitivity, specificity, and accuracy between 2D and 3D TEE, 62 patients with MVP and severe mitral regurgitation were enrolled; surgical appraisal was considered as the gold-standard. Regarding 3D analysis, 54 patients submitted to valvuloplasty were divided in two groups, according to their postoperative mitral regurgitation grades (group 1, absent or grade I mitral regurgitation; and group 2, grade II or III mitral regurgitation). The following parameters were assessed quantitatively by 3D TEE: anteroposterior diameter, commissural width, height, circumference and area of the mitral ring; anterior and posterior leaflets length, leaflets surface area, coaptation length, volume and height billow; distance from the tip of the anterolateral and posteromedial papillary muscle to leaflet border; non-planar and aortic-mitral angles. Univariate analysis (Student t test for continuous variables and Chi-square or Fischer test to the categorical ones), multivariate and ROC curve analyses were performed to identify the relationship between anatomical parameters and surgical results (p < 5%). Results: 2D TEE showed higher sensitivity to diagnose MVP in A2, P1, and P3 segments, when compared with 3D TEE (p= 0.019, 0.023, and 0.012, respectively), while 3D TEE showed greater specificity to identify P1 segment (p= 0.006). No difference was observed in the accuracy between both methods. The presence of bileaflet prolapse (p= 0.041) and the distance from posteromedial papillary muscle to leaflet border (p= 0.038) were higher in group 2. Multivariate analysis showed that bileaflet prolapse and distance of more than 30 mm from posteromedial papillary muscle to leaflet border were related to grade II or III postoperative mitral regurgitation (p= 0.039 and 0.015, respectively), representing 5.3 and 6.3 more risk of significant mitral regurgitation, respectively. Conclusions: Both 2D TEE and 3D TEE presented similar accuracy in the diagnosis of MVP; 2D TEE showed higher sensitivity to diagnose the prolapse in A2, P1 and P3 segments, while the 3D TEE presented greater specificity to identify the affected P1 segment. The distance from the tip of the posteromedial papillary muscle to the leaflet border quantitatively estimated by 3D TEE and the evidence of bileaflet prolapse showed to be associated to the degree of mitral regurgitation after valvuloplasty

No description available.

This diploma thesis’s focuses on the mechanical design of fast solenoid throttle valve for DCC semiactive damper. Current DCC dampers work with a time response of over 10 ms, which is not suitable for fast semiactive control of vehicle chassis. The time response needs to be shortened, to improve quality of regulation. The required time response is archived by new fast electromagnetic actuator for original CES valve. The actuator has been accelerated by reducing induction of eddy currents and by reducing weight of moving parts. New valve helped to reduce the time response of damper by 28 % to 8,1 ms. The results proved, that the time response is affected more by speed of the servo effect, which is closing main orifice, than by electromagnetic actuator. There is no more potential in accelerating CES valve by actuator.

Tomáš ŠTÁBL Design of Gear Timing Mechanism for SI Engine MT, IAE, 2009, 62 pp., 27 fig. This master thesis is concerning the valve train proposal of the spark ignition engine for sports purposes. Antecedent to the actual proposal is the division and retrieval of the modern valve trains, the valve train acting forces description, division and description of the individual valve-lift curve parts , valve springs and the dynamic models of the valve train. In the thesis there are designed the valve lift curves with the continuous course of acceleration, valve springs and valve springs natural oscillations damper for engine Honda CBR 929RR. The dynamic analysis of valve train approach is performed.

The thesis deals with the evaluation of the investment in the fast closing valve replacement in The dam Vranov using Computational fluid dynamics (CFD). The final effects of the fast closing valve replacement will be examined on three different types of valves with regard to the turbine output in operation zone and without the influence of water intake runner and turbine draft tube. The aim of the thesis is to theoretically evaluate alternatives of the fast closing valve replacement and define its basic characteristics and classifications.

Currarino-Silverman syndrome is a rare disorder characterized by premature fusion of manubrio-sternal joint and the sternal segments, resulting in a high carinate chest deformity; it is frequently associated with congenital heart disease. Among the various heart lesions reported in this syndrome, mitral valve disease and coarctation of the aorta have not yet been described (to our knowledge). Our report consists of five children with this syndrome, four of whom had mitral valve disease, with an associated coarctation of the aorta in one patient. The fifth patient had an innocent heart murmur.

Transcatheter aortic valve replacement is a well-established alternative to surgical aortic valve replacement in high-risk patients with severe symptomatic aortic stenosis. Currently, this technique is shifting towards younger patient groups with intermediate- and low-risk profile, which raises the question about long-term durability. Despite acceptable results up to 5 years, little is currently known about valve performance beyond 5 years. Since valve deterioration, thrombosis and endocarditis seem to be the main factors affecting valve durability, precise and widely accepted definitions of these parameters were stated by the European Association of Percutaneous Cardiovascular Interventions (EAPCI) in 2017, followed by the Valve in Valve International Data (VIVID) group definitions in 2018 and the Valve Academic Research Consortium 3 (VARC-3) definitions in 2021. Until the introduction of these definitions, interstudy comparisons were difficult due to missing uniformity. Since the release of these recommendations, an increasing number of studies have reported their data on long-term durability using these new criteria. The aim of the present article is to discuss the current definitions on bioprosthetic valve durability, and to summarize the available data on long-term durability of transcatheter aortic valves.

Compressed air leakage accounts for up to 42% of electrical energy loss on a typical mine compressed air system. By using underground control valves it is possible to reduce the amount of air leakage. Underground valve control was successfully implemented in a South African mine. The project implementation and achieved results are documented in this study. The implementation of underground control valves initially requires a large capital investment. In this study the electrical and financial savings realised by underground valve control and surface valve control were calculated. The payback periods for each control strategy were determined and compared. It was determined that underground valve control can realise up to 40% higher electrical savings than surface control. Depending on the size of the mine and due to the large initial investment, the payback period for an underground valve control system can be up to six times longer than that of a surface control system. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014

Compressed air leakage accounts for up to 42% of electrical energy loss on a typical mine compressed air system. By using underground control valves it is possible to reduce the amount of air leakage. Underground valve control was successfully implemented in a South African mine. The project implementation and achieved results are documented in this study. The implementation of underground control valves initially requires a large capital investment. In this study the electrical and financial savings realised by underground valve control and surface valve control were calculated. The payback periods for each control strategy were determined and compared. It was determined that underground valve control can realise up to 40% higher electrical savings than surface control. Depending on the size of the mine and due to the large initial investment, the payback period for an underground valve control system can be up to six times longer than that of a surface control system. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014