Search Results
Results 501 - 550 of 1771
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Yap Sing-Chien - - 2007
OBJECTIVE: We aimed to compare velocity-encoded cine cardiac magnetic resonance (CMR) with an established echocardiographic method for noninvasive measurement of aortic valve area (AVA) using the continuity equation. METHODS AND RESULTS: Twenty consecutive young adults with stenotic bicuspid aortic valves were examined with CMR and transthoracic echocardiography (TTE). CMR AVA ...
Park Seoung Woo - - 2007
Recently, valve upgrade and/or endoscopic third ventriculostomy, which have the merit of no additional shunting, were introduced for the treatment of slit ventricle syndrome, because lumboperitoneal shunting entails various complications including development of Chiari malformation, shunt malfunction, and infection. However, the safety of valve upgrading is not confirmed, especially in ...
O'Sullivan M Lynne - - 2007
BACKGROUND: Assessment of diastolic function in patients with dilated cardiomyopathy (DCM) has the potential to add valuable information regarding hemodynamics, disease severity, and prognosis. The purpose of this study was to determine transmitral flow (TMF), isovolumic relaxation time (IVRT), pulmonary venous flow (PVF), flow propagation velocity (Vp), and mitral annular ...
Changrue Viboon - - 2007
A laboratory scale microwave vacuum dryer with the ability to record temporal variation of mass and temperature of a drying product was designed and built. The initial study was set up to investigate the effect of the position of a vacuum pressure control valve at two vacuum pressure levels, 6.5 ...
Zannoli Romano - - 2007
Stanford type A aortic dissection often rapidly leads to death from aortic rupture. We considered the possibility of introducing a passive counterpulsating damper into the dissected aorta in order to limit the physical stress associated with ventricular ejection and increase the diastolic aorto-ventricular pressure gradient. We conceived a damping device ...
Kartalov Emil P - - 2007
We report on an electrical microfluidic pressure gauge. A polydimethylsiloxane microvalve closes at a characteristic applied pressure determined by the material's properties and the valve's dimensions. Hence, when the same pressure is applied to all valves of a heterogeneous valve array, some valves close while others remain open. The state ...
Afreen F - - 2007
Emergent aquatic macrophytes growing in waterlogged anaerobic sediments overlain by deep water require particularly efficient ventilating systems. In Phragmites australis (Cav.) Trin. ex Steud, pressurized gas flows, generated by humidity-induced diffusion of air into leaf sheaths, enhance oxygen transport to below-ground parts and aid in the removal of respiratory CO2 ...
Yokoyama Y - - 2006
The aim of this study was to validate the flow characteristics of the novel Helmholtz-Institute Aachen Bileaflet (HIA-BL) heart valve prosthesis. The curved leaflets of the HIA-BL valve form a Venturi passage between the leaflets at peak systole. By narrowing the cross section the flow accelerates and the static pressure ...
Geselschap Jim H - - 2006
PURPOSE: To report the results of in vitro hydrostatic bench testing of a new vein-stent combination to correct deep venous incompetence. METHODS: Twelve valves were constructed from a modified Palmaz stent encased in a segment of great saphenous vein harvested from patients during routine varicose vein surgery. An in vitro ...
Sakamoto Hiroaki - - 2006
The application of repair techniques to treat mitral valve incompetence has increased progressively during the past 20 years. Unfortunately, recent reports have demonstrated the longevity of these repairs to be less than previously believed. Most repair failures are stress related. Computational models to optimize valve repair are in development, but ...
Little Stephen H - - 2007
To investigate the impact of blood pressure (BP) on the Doppler echocardiographic (Doppler-echo) evaluation of severity of aortic stenosis (AS). Handgrip exercise or phenylephrine infusion was used to increase BP in 22 patients with AS. Indices of AS severity (mean pressure gradient (DeltaP(mean)), aortic valve area (AVA), valve resistance, percentage ...
Topaloglu Serkan - - 2007
OBJECTIVE: To determine whether plasma level of soluble P-selectin (sP-selectin) increases in rheumatic mitral stenosis (MS) patients with sinus rhythm, who have scheduled for percutaneous mitral balloon valvuloplasty (PMBV), and to examine the effect of PMBV on sP-selectin level. METHODS: Twenty-six patients with MS and sinus rhythm (study group, 20 ...
Su Ho-Ming - - 2007
Diastolic mitral annular motion may terminate earlier in patients with higher left ventricular end-diastolic pressure (LVEDP). It was therefore hypothesized that the time interval measured from the end of the diastolic mitral annular velocity pattern to the onset of QRS (the AQ interval) would be a useful parameter in predicting ...
McGirt Matthew J - - 2007
INTRODUCTION: The use of programmable shunt valves has increased dramatically in the practice of pediatric hydrocephalus. Despite theoretical advantages, it remains unclear if the use of programmable vs set-pressure valves affects shunt outcome. MATERIALS AND METHODS: The clinical and radiological records of all pediatric patients undergoing ventriculoperitoneal (VP), ventriculopleural (VPl), ...
Sato Kimitoshi - - 2006
Although the Codman Hakim programmable valve (CHPV) system is popular, several problems arising from its design have been described. The authors report an additional cause of shunt failure associated with the use of the CHPV system. A 7-year-old girl who had previously undergone placement of a ventriculoperitoneal shunt with the ...
Kato Takayoshi - - 2006
Mediastinitis following ascending aortic replacement is intractable and potentially fatal, and the feature is characterized as having both high mortality and morbidity when its causation pathology is methicillin-resistant Staphylococcus aureus (MRSA). Possible treatments for the condition, which include debridement, irrigation, and healthy tissue transposition, often result in failure. We report ...
Linde Annika - - 2006
This study was conducted to estimate the incidence of aortic stenosis (AS) in a group of Boxers evaluated by auscultation, ECG, blood pressure measurement and Doppler-echocardiography. The Boxer is a breed at significantly increased risk of AS. The prevalence of murmurs and Doppler-echocardiographic findings consistent with AS in this breed ...
Jimenez Jorge H - - 2006
BACKGROUND: Although edge-to-edge repair is an established adjunctive procedure, there is still debate on its long-term durability and efficacy. METHODS: Fifteen porcine mitral valves were studied in a physiologic left heart simulator with a variable size annulus (dilated = 8.22 cm2, normal = 6.86 cm2, contracted = 5.5 cm2). Mitral ...
Goetz Wolfgang A - - 2006
Systolic descent of the atrioventricular plane toward the relatively stationary left ventricular apex is well described. As the atrioventricular plane includes two separate valvular units, systolic atrioventricular plane displacement should not be homogenous. In 6 sheep, sonomicrometric crystals were implanted at the base of the right coronary sinus, anterolateral and ...
Asada-Kamiguchi Junko - - 2006
BACKGROUND: Left ventricular aneurysm (LVA) may affect diastolic intraventricular blood flow. Color M-mode (CMM) Doppler flow propagation patterns are abnormal in the presence of apical aneurysms. The aim of this study was to validate the accuracy of CMM echocardiography for assessing the existence and size of LVA and to determine ...
Tou Sandra P - - 2006
BACKGROUND: Systemic hypertension is likely underdiagnosed in veterinary medicine because systemic blood pressure is rarely measured. Systemic blood pressure can theoretically be estimated by echocardiography. According to the modified Bernoulli equation (PG = 4v(2)), mitral regurgitation (MR) velocity should approximate systolic left ventricular pressure (sLVP), and therefore systolic systemic blood ...
Saito Shunei - - 2006
OBJECTIVE: We have recently reported our isolated and working swine heart model that examines the valve motion precisely by a high-speed digital video camera system. Using this modality, the present study aimed (1) to delineate the motion of the mitral leaflets, chords and annulus throughout the cardiac cycle, and (2) ...
Mihalatos Dennis G - - 2006
OBJECTIVES: We defined the effects of the operative (OP) state and phenylephrine challenge on the assessment of mitral regurgitation (MR) severity. METHODS: In all, 57 patients underwent transesophageal echocardiographic assessment of MR severity pre-OP (PREOP) and intra-OP. MR severity was assessed PREOP under conscious sedation and intra-OP with general anesthesia, ...
Kadem Lyes - - 2006
BACKGROUND AND AIM OF THE STUDY: In patients with aortic stenosis (AS), it has been reported that the transvalvular pressure gradients (APs) may be reduced or even abolished in the presence of concomitant arterial hypertension, but the mechanisms underlying this phenomenon remain unclear. The study aim was to: (i) examine ...
Webb John G - - 2006
OBJECTIVES: We describe the technique of, and our experience with, rapid ventricular burst pacing to facilitate transcatheter heart valve implantation. BACKGROUND: Endovascular therapeutic procedures frequently require the precise placement of implantable devices. The precision of transcatheter device deployment may be hampered by cardiac motion or the effects of intravascular flow. ...
Bae Jang-Ho - - 2006
BACKGROUND: Determination of a transvalvular pressure gradient for measurement of aortic valve area (AVA) by hemodynamic cardiac catheterization usually requires 2 catheters and 2 arterial access sites. We assessed the feasibility of using a single arterial puncture and a 0.014 inch pressure wire for evaluation of aortic stenosis. METHODS: Eighteen ...
Chong Colin C W - - 2006
We previously reported 52 patients with hydrocephalus who were followed up after insertion of low-pressure Novus valves. These valves have a normally open anti-siphon device (ASD) incorporated. There were no cases of subdural haematomas (SDH). Subsequently, three new patients suffered SDH after insertion of these valves. We investigated a simple ...
Utsuki Satoshi - - 2006
A 7-year-old girl presented in semicomatose condition. She had received a ventriculoperitoneal shunt using a Codman-Hakim programmable valve. Head computed tomography demonstrated hydrocephalus and head radiography showed that the pressure setting of the shunt valve had changed to 60 mmH(2)O from 40 mmH(2)O. The pressure setting was returned to 40 ...
Dohmen Guido - - 2006
BACKGROUND AND AIM OF THE STUDY: The newly designed, so-called 'high performance' bileaflet heart valve prostheses are suggested to be especially beneficial in small sizes. Herein, valvular energy loss and transvalvular gradients were evaluated using an in-vitro pulsatile flow model for aortic prostheses (St. Jude Medical Regent and On-X, sizes ...
de Kort Ellen - - 2006
The aim was to investigate the effects of balloon dilation of congenital valvar aortic (Ao) stenosis on heart function with conventional and with new echocardiographic techniques. Nine patients, preballoon and 1 to 4 d postballoon dilation of Ao-valve, were included in the study. Assessment of heart function was made by ...
Estrada Amara - - 2006
BACKGROUND: In dogs, treatment of pulmonic valve stenosis (PS) with pulmonary balloon valvuloplasty (PBV) is a viable method to decrease the pressure gradient across the valve. However, to the authors' knowledge, the variables that influence the selection of the correct balloon size for the procedure have not been explored. Moreover, ...
Páez J M García - - 2006
We studied the mechanical behavior of membranes of calf pericardium, similar to those employed in prosthetic valve leaflets, when subjected to tensile fatigue. The objective was to assess its durability, as a fundamental property of cardiac bioprosthesis, and analyze the energy consumption. For this purpose, the authors built a hydraulic ...
Ishikawa S - - 2006
Dexmedetomidine hydrochloride (Prece-dex(R)) is a potent and highly selective central a2-adrenoreceptor agonist. Dexmedetomidine has recently been approved as a new sedative drug, however, its hemodynamic effects on patients just after cardiac surgery has not been established. Nineteen patients (14 males and 5 females) who underwent elective cardiovascular surgery were included ...
Cuniberti Luis A - - 2006
OBJECTIVES: This study was designed to investigate the association between hypertension and aortic valve stenosis (AVS) in a rabbit model. BACKGROUND: Degenerative AVS is a prevalent disease in elderly persons. Its molecular mechanisms remain unclear, in part because of the absence of experimental models. Epidemiologic data suggest a link between ...
Nilsson Bo - - 2006
OBJECTIVE: We investigated the feasibility and reproducibility of transesophageal (TE) recordings of displacements and velocities of 4 sites of the mitral annulus in anesthetized patients. Correlations to transthoracic measures and influence of the respiratory cycle were also investigated. METHODS: A total of 24 patients without heart disease were included. Another ...
Estrada Amara - - 2006
Calculation of stenotic valve area can aide in the determination of the severity of the lesion. While use of Doppler derived pressure gradients are widely used and easily interpreted, certain situations may make these measurements less reliable. The purpose of this paper is to demonstrate the technique for measuring the ...
Dohmen G - - 2006
BACKGROUND: Pressure recovery is not taken into account when calculating trans-prosthetic gradients after mechanical valve replacement using Doppler echocardiography. This may lead to underestimation of valvular performance. METHODS: Simultaneous measurement of Doppler and direct trans-prosthetic gradients was performed in a circulatory mock loop simulator with physiologic parameters at different heart ...
Devbhandari M P - - 2006
The non-invasive method of blood pressure measurement is regarded as a safe procedure and the reports of any serious complications are rare. We report a unique case of extensive skin necrosis due to an intermittently inflating blood pressure cuff in a 65-year-old critically ill lady following a third time redo ...
Mitlyng Benjamin L - - 2006
First-generation prosthetic heart valves commonly caused sufficient red blood cell (RBC) injury to induce hemolytic anemia. Although multiple studies have shown that new-generation valves are not associated with anemia, the extent to which these valves are injurious to RBCs is not known, because RBC survival not has not been measured ...
Ikhumetse Josepha D - - 2006
BACKGROUND AND AIM OF THE STUDY: Native pulmonary valve leaflets (PVL) are exposed to lower pressures compared to aortic valve leaflets. Knowledge of the biology of PVL exposed to aortic pressures is limited. Hence, the study's aim was to investigate the biological properties of PVL subjected to normal aortic pressures. ...
Lee H - - 2006
In previous studies, we investigated the cavitation phenomenon in a mechanical heart valve using an electro-hydraulic total artificial heart. With this system, a 50% glycerin solution kept at 37 degrees C was used as the working fluid. We reported that most of the cavitation bubbles were observed near the valve ...
Dalmau María José - - 2006
This study compares the implantation characteristics and the hemodynamic performance of the new Carpentier-Edwards Perimount Magna (CEPM) xenograft with those of the standard Perimount (CEPS) valve in the aortic position. Eighty consecutive patients surviving an aortic valve replacement with either the CEPS valve (n=40) or the CEPM prosthesis (n=40) in ...
Goetz Wolfgang A - - 2006
OBJECTIVE: New pericardial aortic bioprostheses (3F Therapeutics and temporarily stented autologous pericardial valve prosthesis) were developed recently. These valves are designed with commissures connected to the aortic wall at only three single points (single point attached commissures (SPAC)). The aim of this study was to investigate the forces acting on ...
Wong Graham C - - 2006
BACKGROUND: Chronic mitral regurgitation imparts a volume load on the left atrium (LA). Because this chamber may dilate asymmetrically, changes in left atrial size may be underestimated using standard two-dimensional or M-mode techniques. METHODS: The effect of lisinopril therapy in the setting of chronic organic mitral regurgitation on LA dimension ...
Hendriks Johanna M - - 2006
PURPOSE: To investigate the pressure gradient and degree of flow reduction associated with embolus protection filters for carotid stenting in an in vitro experiment. METHODS: Three filter devices with a perforated membrane design and one wire mesh type filter were tested. At a pressure of 70 mmHg, the flow reduction ...
Warnock James N - - 2006
BACKGROUND AND AIM OF THE STUDY: Cardiovascular risk factors are believed to play a role in the pathogenesis of aortic valve disease. In the present study the hypothesis was proposed that elevated pressure would cause a change in the expression of prototypical pro-inflammatory genes. Hence, the expression of MCP-1, osteopontin ...
Meier U - - 2006
Does the opening pressure of hydrostatic shunts influence the clinical outcome for patients suffering from idiopathic normal-pressure hydrocephalus (NPH)? Between September 1997 and January 2003, 123 patients with idiopathic NPH were surgically treated by implanting a hydrostatic shunt at the Departments of Neurosurgery of the Unfallkrankenhaus Berlin and the University ...
Ha Jong-Won - - 2006
Mitral inflow filling pattern usually consists of 2 forward flow velocities in sinus rhythm: early rapid filling (E) and late filling with atrial contraction (A). However, additional mid-diastolic flow velocity may be present resulting in triphasic mitral inflow filling pattern. When mitral inflow is triphasic, mitral annulus velocity recorded by ...
Meier U - - 2006
A better course of the disease after implantation of a low-pressure valve in patients with idiopathic normal pressure hydrocephalus normally comes at the cost of a distinctly higher rate of overdrainage. Can combining an adjustable valve with a gravity unit produce optimization of treatment results? In a prospective observation of ...
Olson Jeffrey J - - 2006
The early mitral filling velocity (E)/early diastolic mitral annular velocity (E') ratio is increasingly being used as a simplified approach to estimate left ventricular (LV) filling pressure. The validity of applying this Doppler parameter to patients with severe mitral regurgitation is unknown. We retrospectively identified 20 patients in sinus rhythm ...
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