The Experts below are selected from a list of 72 Experts worldwide ranked by ideXlab platform
John E Deanfield - One of the best experts on this subject based on the ideXlab platform.
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electrical remodelling following percutaneous Pulmonary Valve implantation in congenital heart Disease
Heart, 2009Co-Authors: C M Plymen, Johannes Nordmeyer, Pier D Lambiase, A Bolger, Mark S Turner, Twin Yen Lee, Philip Lurz, L Coats, A M Taylor, John E DeanfieldAbstract:Aims Sudden cardiac death in congenital heart Disease is related to increased right ventricular end diastolic volume (RVEDV), QRS prolongation and abnormalities of QRS, JT and QT dispersions. Surgical Pulmonary Valve replacement (PVR) and percutaneous Pulmonary Valve replacement (PPVI) both reduce RVEDV, although the effects of PPVI on surface ECG parameters are unknown. PPVI entails the isolated correction of Pulmonary Valve lesions independent of direct surgical intervention on the right ventricle, and as such represents a pure model of right ventricular mechanical and electrophysiological changes post-PVR. Surgical studies have so far failed to show consensus on significant changes in QRS duration post-procedure, and have shown no significant changes in QRS or QT dispersion values, possibly due to the direct effects of surgery on the right ventricular myocardium. This prospective study therefore sought to determine the effects of PPVI on QRS duration and QRS, JT and QT dispersion values. Methods 109 PPVI patients with congenital heart Disease (aged 22.9 ± 10.6 years) were studied preprocedure, at 24 h and 1 year postoperatively with transthoracic echocardiography and cardiac magnetic resonance imaging and additionally at 3 and 6 months with ECG. 55% had Pulmonary stenosis, 27% Pulmonary regurgitation and 19% mixed lesions. Diagnosis included Pulmonary atresia (30%), tetralogy of Fallot (28%), transposition of the creat arteries (12%), truncus arteriosus (12%), congenital aortic or Pulmonary Valve Disease (15%) and double outlet right ventricle (3%). Results QTc, QRSd, QTd and JTd all showed significant reductions at one year (p Conclusions PPVI represents a pure model of relief from the haemodynamic consequences of right ventricular stretch compared with its surgical counterpart. This is the first study reporting electrical remodelling following isolated Pulmonary Valve replacement, and it confirms that right ventricular haemodynamics significantly improve post-PPVI. QRS duration shows no significant change. However, QTc, QTd, QRSd and JTd significantly improve at one year follow-up. Older patients and those with stenotic valvar lesions have greater changes in ECG parameters (fig 2). This study suggests that PPVI is associated with electrocardiographic remodelling to a greater degree than reported in surgical PVR.
Ninh Huu Dang - One of the best experts on this subject based on the ideXlab platform.
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percutaneous stent mounted Valve for treatment of aortic or Pulmonary Valve Disease
Catheterization and Cardiovascular Interventions, 2004Co-Authors: John G Webb, B Munt, Raj Makkar, Tasneem Z Naqvi, Ninh Huu DangAbstract:The objective of this study was to develop a prosthetic cardiac Valve designed for percutaneous transcatheter implantation. Percutaneous catheter-based therapies play a limited role in the management of cardiac Valve Disease. Surgical implantation of prosthetic Valves usually requires thoracotomy and cardioPulmonary bypass. The stent-Valve is constructed of a rolled sheet of heat-treated nitinol. Although malleable when cooled, once released from a restraining sheath at body temperature the stent unrolls, becomes rigid, and assumes its predetermined cylindrical conformation. A ratcheting lock-out mechanism prevents recoil and external protrusions facilitate anchoring. Valve leaflets are constructed of bovine pericardium. The feasibility of catheter implantation, prosthetic Valve function, and survival were investigated in an animal model. In vitro and pulse duplicator testing documented Valve durability. Endovascular delivery of the prototype stent-Valve to the aortic or Pulmonary position was feasible. Accurate positioning was required to ensure exclusion of the native Valve leaflets and, in the case of the aortic Valve, to avoid compromise of the coronary ostia or mitral apparatus. Oversizing of the stent in relation to the Valve annulus was desirable to facilitate anchoring and prevent paravalvular insufficiency. Stent-Valve implantation proved feasible and compatible with survival in an animal model. Transcatheter implantation of prosthetic Valves is possible. Further evolution of this technology will involve lower-profile devices with design features that facilitate vascular delivery, visualization, positioning, deployment, and valvular function.
C M Plymen - One of the best experts on this subject based on the ideXlab platform.
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electrical remodelling following percutaneous Pulmonary Valve implantation in congenital heart Disease
Heart, 2009Co-Authors: C M Plymen, Johannes Nordmeyer, Pier D Lambiase, A Bolger, Mark S Turner, Twin Yen Lee, Philip Lurz, L Coats, A M Taylor, John E DeanfieldAbstract:Aims Sudden cardiac death in congenital heart Disease is related to increased right ventricular end diastolic volume (RVEDV), QRS prolongation and abnormalities of QRS, JT and QT dispersions. Surgical Pulmonary Valve replacement (PVR) and percutaneous Pulmonary Valve replacement (PPVI) both reduce RVEDV, although the effects of PPVI on surface ECG parameters are unknown. PPVI entails the isolated correction of Pulmonary Valve lesions independent of direct surgical intervention on the right ventricle, and as such represents a pure model of right ventricular mechanical and electrophysiological changes post-PVR. Surgical studies have so far failed to show consensus on significant changes in QRS duration post-procedure, and have shown no significant changes in QRS or QT dispersion values, possibly due to the direct effects of surgery on the right ventricular myocardium. This prospective study therefore sought to determine the effects of PPVI on QRS duration and QRS, JT and QT dispersion values. Methods 109 PPVI patients with congenital heart Disease (aged 22.9 ± 10.6 years) were studied preprocedure, at 24 h and 1 year postoperatively with transthoracic echocardiography and cardiac magnetic resonance imaging and additionally at 3 and 6 months with ECG. 55% had Pulmonary stenosis, 27% Pulmonary regurgitation and 19% mixed lesions. Diagnosis included Pulmonary atresia (30%), tetralogy of Fallot (28%), transposition of the creat arteries (12%), truncus arteriosus (12%), congenital aortic or Pulmonary Valve Disease (15%) and double outlet right ventricle (3%). Results QTc, QRSd, QTd and JTd all showed significant reductions at one year (p Conclusions PPVI represents a pure model of relief from the haemodynamic consequences of right ventricular stretch compared with its surgical counterpart. This is the first study reporting electrical remodelling following isolated Pulmonary Valve replacement, and it confirms that right ventricular haemodynamics significantly improve post-PPVI. QRS duration shows no significant change. However, QTc, QTd, QRSd and JTd significantly improve at one year follow-up. Older patients and those with stenotic valvar lesions have greater changes in ECG parameters (fig 2). This study suggests that PPVI is associated with electrocardiographic remodelling to a greater degree than reported in surgical PVR.
Johannes Nordmeyer - One of the best experts on this subject based on the ideXlab platform.
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electrical remodelling following percutaneous Pulmonary Valve implantation in congenital heart Disease
Heart, 2009Co-Authors: C M Plymen, Johannes Nordmeyer, Pier D Lambiase, A Bolger, Mark S Turner, Twin Yen Lee, Philip Lurz, L Coats, A M Taylor, John E DeanfieldAbstract:Aims Sudden cardiac death in congenital heart Disease is related to increased right ventricular end diastolic volume (RVEDV), QRS prolongation and abnormalities of QRS, JT and QT dispersions. Surgical Pulmonary Valve replacement (PVR) and percutaneous Pulmonary Valve replacement (PPVI) both reduce RVEDV, although the effects of PPVI on surface ECG parameters are unknown. PPVI entails the isolated correction of Pulmonary Valve lesions independent of direct surgical intervention on the right ventricle, and as such represents a pure model of right ventricular mechanical and electrophysiological changes post-PVR. Surgical studies have so far failed to show consensus on significant changes in QRS duration post-procedure, and have shown no significant changes in QRS or QT dispersion values, possibly due to the direct effects of surgery on the right ventricular myocardium. This prospective study therefore sought to determine the effects of PPVI on QRS duration and QRS, JT and QT dispersion values. Methods 109 PPVI patients with congenital heart Disease (aged 22.9 ± 10.6 years) were studied preprocedure, at 24 h and 1 year postoperatively with transthoracic echocardiography and cardiac magnetic resonance imaging and additionally at 3 and 6 months with ECG. 55% had Pulmonary stenosis, 27% Pulmonary regurgitation and 19% mixed lesions. Diagnosis included Pulmonary atresia (30%), tetralogy of Fallot (28%), transposition of the creat arteries (12%), truncus arteriosus (12%), congenital aortic or Pulmonary Valve Disease (15%) and double outlet right ventricle (3%). Results QTc, QRSd, QTd and JTd all showed significant reductions at one year (p Conclusions PPVI represents a pure model of relief from the haemodynamic consequences of right ventricular stretch compared with its surgical counterpart. This is the first study reporting electrical remodelling following isolated Pulmonary Valve replacement, and it confirms that right ventricular haemodynamics significantly improve post-PPVI. QRS duration shows no significant change. However, QTc, QTd, QRSd and JTd significantly improve at one year follow-up. Older patients and those with stenotic valvar lesions have greater changes in ECG parameters (fig 2). This study suggests that PPVI is associated with electrocardiographic remodelling to a greater degree than reported in surgical PVR.
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finite element analysis of stent deployment understanding stent fracture in percutaneous Pulmonary Valve implantation
Journal of Interventional Cardiology, 2007Co-Authors: Silvia Schievano, Francesco Migliavacca, Gabriele Dubini, Lorenza Petrini, Johannes Nordmeyer, Sachin Khambadkone, Louise Coats, Philipp Lurz, Andrew M Taylor, Philipp BonhoefferAbstract:OBJECTIVES: To analyze factors responsible for stent fracture in percutaneous Pulmonary Valve implantation (PPVI) by finite element method. BACKGROUND: PPVI is an interventional catheter-based technique for treating significant Pulmonary Valve Disease. Stent fracture is a recognized complication. METHODS: Three different stent models were created: (1) platinum-10% iridium alloy stent - resembles the first-generation PPVI device; (2) same geometry, but with the addition of gold over the strut intersections - models the current stent; (3) same design as 1, but made of thinner wire. For Model 3, a stent-in-stent solution was applied. Numerical analyses of the deployment of these devices were performed to understand the stress distribution and hence stent fracture potential. RESULTS: Model 1: Highest stresses occurred at the strut intersections, suggesting that this location may be at highest risk of fracture. This concurs with the in vivo stent fracture data. Model 2: Numerical analyses indicate that the stresses are lower at the strut intersections, but redistributed to the end of the gold reinforcements. This suggests that fractures in this device may occur just distal to the gold. This is indeed the clinical experience. Model 3 was weakest at bolstering the implantation site; however, when two stents were coupled (stent-in-stent technique), better strength and lower stresses were seen compared with Model 1 alone. CONCLUSIONS: Using finite element analysis of known stents, we were able to accurately predict stent fractures in the clinical situation. Furthermore, we have demonstrated that a stent-in-stent technique results in better device performance, which suggests a novel clinical strategy.
Heidi M Connolly - One of the best experts on this subject based on the ideXlab platform.
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abstract 20034 fate of the native Pulmonary Valve in patients with carcinoid heart Disease after tricuspid Valve replacement
Circulation, 2016Co-Authors: Sushil Allen Luis, Patricia A Pellikka, Hartzell V Schaff, Heidi M ConnollyAbstract:Background: Carcinoid heart Disease most frequently affects the right sided Valves. In carcinoid patients undergoing tricuspid Valve replacement, uncertainty exists regarding the surgical management of Pulmonary Valve Disease in the absence of severe Pulmonary Valve dysfunction. We aimed to determine the long-term fate of the native Pulmonary Valve after tricuspid Valve replacement (TVR) for carcinoid heart Disease. Methods and results: A retrospective review of 222 surgical patients, operated at our institution between 1985 - 2015, identified 34 patients who underwent TVR without Pulmonary Valve intervention. After exclusion of 17 patients with Conclusions: Although rare, tricuspid carcinoid Valve Disease without Pulmonary Valve involvement at cardiac surgery was associated with a low risk of subsequent Pulmonary Valve dysfunction and need for subsequent surgical intervention. Hence, it is reasonable to perform TVR without concomitant Pulmonary Valve intervention, when preoperative testing demonstrates moderate or less PR.
