Search Results
Results 251 - 300 of 2022
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Muehlschlegel Jochen D - - 2008
BACKGROUND AND AIM: Patients with low ejection fraction (EF) undergoing myocardial revascularization frequently require ventricular pacing following cardiopulmonary bypass (CPB). While the benefits of chronic biventricular (BiV) pacing in patients with low EF are well established, there are little data on acute effects during heart surgery. This study analyzed the ...
Batra Anjan S - - 2008
Temporary epicardial pacing is commonly used for the diagnosis and treatment of arrhythmias in the acute post operative period after surgery for congenital heart disease. Temporary epicardial pacemakers have become increasingly sophisticated over the years and have evolved from simple single chamber devices with few programmable parameters to complex dual ...
Zhao Xiaopeng - - 2008
Cardiac alternans, a beat-to-beat alternation in action potential duration (at the cellular level) or in electrocardiogram morphology (at the whole heart level), is a marker of ventricular fibrillation, a fatal heart rhythm that kills hundreds of thousands of people in the United States each year. Investigating cardiac alternans may lead ...
Glatz Andrew C - - 2008
OBJECTIVE: Risk factors for poor outcome with congenital complete heart block include prematurity, low birth weight, hydrops, low ventricular rates, and congenital heart disease. In this group, medical therapy is often ineffective, pacing is technically challenging, and mortality exceeds 80%. The purpose of this study is to assess outcomes of ...
Healy David G - - 2008
We have previously demonstrated the role of univentricular pacing modalities in influencing coronary conduit flow in the immediate post-operative period in the cardiac surgery patient. We wanted to determine the mechanism of this improved coronary conduit and, in addition, to explore the possible benefits with biventricular pacing. Sixteen patients undergoing ...
Turley Andrew J - - 2008
A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether bi-ventricular pacing, also referred to as cardiac resynchronisation therapy (CRT), improves survival and quality of life in patients with severe (NYHA III/IV) symptomatic heart failure. Cardiac pacing can be achieved by ...
Buckberg Gerald - - 2008
OBJECTIVE: Understanding cardiac function requires knowledge of the architecture responsible for the normal actions of emptying and filling. Newer imaging methods are surveyed to characterize directional (narrowing, shortening, lengthening, and widening) and twisting motions. METHODS: These movements are defined and then compared with a spectrum of models to introduce a ...
Anh Daejoon - - 2008
BACKGROUND: The impact of altered ventricular activation, including biventricular (BV) pacing, on T-wave alternans (TWA) and arrhythmic substrates is unclear. We studied how differing ventricular activation sequence alters TWA; the interval from peak-to-end of the T-wave (TpTe) and T-wave amplitude during right (RV), left (LV), and biventricular (BV) pacing; and ...
Matsushita Takehiko - - 2008
Although advancement of succeeding atrial activation by a ventricular extrastimulus (VES) on His refractoriness during supraventricular tachycardia (SVT) has been used as evidence of an accessory pathway (AP), the sensitivity of this method is suboptimal. This study was designed to compare the His-His (H-H) and atrial-atrial (A-A) intervals of the ...
Sweeney Michael O - - 2008
AV Decoupling During Enhanced AAIR Pacing. BACKGROUND: Enhanced AAI/R pacing minimizes right ventricular pacing but may permit or induce AV decoupling (AV-DC) due to unrestricted AV intervals (AVIs). The purpose of this study was to characterize and quantify AVI behavior in a randomized trial of enhanced AAI/R pacing in ICD ...
Evonich Rudolph F - - 2008
OBJECTIVE: The objective was to evaluate the effects of atrial synchronous biventricular pacing in postoperative patients with severe cardiomyopathy. METHODS: Atrial synchronous biventricular pacing epicardial leads were placed during cardiac surgery in patients with an ejection fraction of 30% or less. Patients were randomized to usual care pacing, the mode ...
Friedman Howard S - - 2008
BACKGROUND: Ventricular aberrant conduction has a confounding effect on the known relationships between the electrocardiogram (ECG) and left ventricular (LV) mass. By relating the ECG of right ventricular pacing to LV mass and to nonpaced recordings, clarification of these effects might emerge. METHODS AND RESULTS: In 30 patients (age, 81 ...
Tomaske Maren - - 2008
BACKGROUND: Cardiovascular abnormalities and small vascular size may preclude transvenous pacing and necessitate epicardial lead implantation. This study evaluates the performance of steroid-eluting, bipolar epicardial pacing leads. METHODS: We prospectively enrolled 114 children with 239 atrial and ventricular bipolar epicardial leads (Medtronic CapSure 10366 or 4968, Minneapolis, MN), followed up ...
Styliadis Ioannis H - - 2008
INTRODUCTION: Indications for pacing and pacing mode prescription have changed in the past decades following advances in pacemaker technology. The aim of the present study was to evaluate changes in indications for pacing and pacing modes during the years 1989-2006 in a single academic pacemaker centre in Northern Greece. METHODS: ...
van Gelder Berry M - - 2008
BACKGROUND: Optimization of cardiac resynchronization therapy (CRT) with respect to the interventricular (V-V) interval is mainly limited to pacing at a resting heart rate. We studied the effect of higher stimulation rates with univentricular and biventricular (BiV) pacing modes including the effect of the V-V interval optimization. METHODS: In 36 ...
Yin Lixue L Echocardiography and Non-invasive Cardiology Laboratory, Sichuan Academy of Medical Science & Sichuan Provincial Hospital, Chengdu, - - 2008
His bundle pacing (HBP) results in rapid synchronous ventricular activation, but has been associated with long procedure times and compromised pacing and sensing performance. This study sought to reduce procedure time and radiation exposure, and improve electrical performance through more accurate lead placement. Intracardiac echocardiography (ICE) was used to guide ...
Veenhuyzen George D - - 2008
BACKGROUND: Diagnostic supraventricular tachycardia (SVT) features and pacing maneuvers tend to be specific but insensitive. Therefore, diagnosis often requires the integration of multiple pieces of information and/or pacing maneuvers, which adds to the complexity of catheter ablation procedures. OBJECTIVE: The purpose of this study was to determine if a single ...
Zanon Francesco - - 2008
AIMS: The His bundle is regarded as the most physiological site for ventricular pacing, in that it avoids the adverse effects of right ventricular apical pacing (RVAP). However, very few studies have compared the effects of direct His bundle pacing (DHBP) and RVAP. The aim of our study was the ...
Rogers Dominic P S - - 2008
Biventricular (BiV) pacing is an established therapy for heart failure in ischaemic and dilated cardiomyopathy. Its effects in end-stage hypertrophic cardiomyopathy (HCM) are unknown. To assess the potential benefits of BiV pacing in patients with symptomatic end-stage HCM. Twenty patients with non-obstructive HCM (12 male, mean age 57+/-13 years), left ...
Manolis Antonis S - - 2008
Cardiac pacing from the right ventricular apex is the most common site of cardiac pacing. During the last decade, several studies demonstrated the harmful effects of the iatrogenic left bundle branch block, which is observed in cardiac pacing from the right ventricular apex. These observations led to an interest in ...
Frattini Folco - - 2008
The optimal left ventricular pacing location for cardiac resynchronization therapy should be individualized according to the site of maximal mechanical delay. However, the presence of vein stenosis or kinking in coronary sinus (CS) anatomy could hamper lead implantation in the target vessel. We describe the case of a patient with ...
ten Cate Tim J F - - 2008
AIMS: A depressed left ventricular function (LVF) is sometimes observed during right ventricular apical (RVA) pacing, but any prediction of this adverse effect cannot be done. Right ventricular outflow tract (RVOT) pacing is thought to deteriorate LVF less frequently because of a more normal LV activation pattern. This study aims ...
Siegrist Patrick T - - 2008
PURPOSE: 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). METHODS: In ...
Dolara Alberto - - 2008
A case of an adult patient with congenital complete heart block is reported in whom acute heart failure followed pacemaker implantation. It is uncertain whether the associated cardiomyopathy was present since birth, although right ventricular pacing was probably responsible for further deterioration of myocardial function. Synchronous pacing of both ventricles ...
Capucci Alessandro - - 2008
OBJECTIVE: This research study tests the hypothesis that atrial pacing near the atrioventricular node during atrial fibrillation can affect ventricular rate. METHODS: In 13 patients, two monophasic action potential catheters were advanced into the low anterior septum (ANT) and the low posterior septum (POST) near the atrioventricular node. After induction ...
Fak Ali Serdar - - 2008
BACKGROUND: Compared to atrioventricular sequential pacing, ventricular demand pacing is known to have somewhat more deleterious hemodynamic effects, which probably arise from increased sympathetic tonus and inappropriate baroreceptor activation. Endothelial function is affected by various local and systemic factors including baroreceptor activity. The aim of this study was to explore ...
Giazitzoglou Eleftherios - - 2008
INTRODUCTION: Failure to achieve left ventricular pacing remains one of the obstacles to cardiac resynchronisation therapy. METHODS: A new technique for the placement of left ventricular pacing leads in the tributaries of the coronary sinus is described. Antegrade visualisation of the coronary sinus is accomplished by selective coronary angiography and ...
Quesada Aurelio - - 2008
AIMS: Several clinical studies have shown that, in patients with intact atrioventricular (AV) conduction, unnecessary chronic right ventricular (RV) pacing can be detrimental. The managed ventricular pacing (MVP) algorithm is designed to give preference to spontaneous AV conduction, thus minimizing RV pacing. The clinical outcomes of MVP are being studied ...
Bordachar Pierre - - 2008
INTRODUCTION: The peak of endocardial acceleration (PEA) is an index of myocardial contractility. We aimed to (1) demonstrate that the PEA measured by the noninvasive cutaneous precordial application of an accelerometer sensor is related to left ventricular (LV) dP/dt max and (2) assess the usefulness of PEA monitoring during graded ...
Taccardi Bruno - - 2008
Published studies show that ventricular pacing in canine hearts produces three distinct patterns of epicardial excitation: elliptical isochrones near an epicardial pacing site, with asymmetric bulges; areas with high propagation velocity, up to 2 or 3 m/s and numerous breakthrough sites; and lower velocity areas (<1 m/s), where excitation moves ...
Fung Jeffrey W H - - 2009
Right ventricular (RV) pacing related heart failure is reported in some patients after long term pacing. The exact mechanism is not yet clear but may be related to left ventricular (LV) dyssynchrony induced by RV apical pacing. We report one case with baseline normal LV ejection fraction but complicated by ...
Fornwalt Brandon K - - 2008
INTRODUCTION: Patients with heart block have conventionally received a pacemaker that stimulates the right ventricular apex (RVA) to restore heart rate control. While RVA pacing has been shown to create systolic dyssynchrony acutely, dyssynchrony can also occur in diastole. The effects of acute RVA pacing on diastolic synchrony have not ...
Villain Elisabeth - - 2008
BACKGROUND: Advances in pacing technology have increased indications for antibradycardia pacing and new indications have appeared for treatment of atrial tachycardia and cardiac failure in patients with congenital heart disease (CHD). METHODS AND RESULTS: Implantation of a pacemaker is mandatory for symptomatic children with complete atrio-ventricular block (CAVB). In asymptomatic ...
Vanagt Ward Y - - 2008
Children with congenital or acquired atrioventricular block are provided with ventricular rate support from a pacing lead that traditionally is positioned at the right ventricular (RV) apex. However, RV apical pacing causes dyssynchronous electrical activation and left ventricular (LV) contraction, resulting in decreased LV function. Chronic RV apical pacing leads ...
Valzania Cinzia - - 2008
BACKGROUND: Although left ventricular (LV) pacing has been proposed as an alternative to biventricular (BIV) pacing for heart failure (HF) patients, few comparative data are available on the electromechanical effects of these pacing modalities at mid-term follow-up. AIM: To investigate the clinical and echocardiographic effects of LV versus BIV pacing ...
Chirife Raul - - 2008
Cardiac pacing creates spurious delays between and within the cardiac chambers. These are: 1. Left atrial (LA) transport delay (ATD) either sensed (s) or paced (p), (time from right atrial P-wave to the end of LA transport (mitral Doppler A-wave)). 2. Interventricular delay (IVD), (time from onsets of right (RV) ...
Pürerfellner Helmut - - 2008
BACKGROUND: Managed Ventricular Pacing (MVP) and Search AV+ (SAV+) are two pacing algorithms designed to reduce ventricular pacing. MVP promotes conduction by operating in AAI/R mode with backup ventricular pacing during atrioventricular block (AVB). SAV+ operates in DDD/R mode with a nominal AV extension of 290 ms during atrial sensing ...
Yang Shu-sen - - 2008
BACKGROUND: Renin-angiotensin-aldosterone system has been demonstrated to be associated with both congestive heart failure (CHF) and atrial fibrillation (AF). This study investigated the effects of spironolactone, a kind of aldosterone antagonist, on atrial electrical remodeling and fibrosis in CHF dogs induced by chronic rapid ventricular pacing. METHODS: Twenty one dogs ...
Kutarski Andrzej - - 2008
BACKGROUND: Atrial conduction disturbances are a known substrate of re-entrant atrial arrhythmia, and their detection is important for the selection of proper therapy. Time-domain analysis of P-wave in signal-averaged ECG (SA-ECG) recorded from chest leads is an accepted method evaluating inhomogeneity of atrial excitation, predictive for atrial arrhythmias. Biatrial (BiA) ...
Schmidt Mandi - - 2008
This study investigated the feasibility of using a modified transesophageal atrial pacing system for dogs requiring temporary ventricular pacing. Atrial pacing was readily achieved in the one dog studied, but it caused considerable diaphragmatic movement. Ventricular pacing could not be achieved at any lead configuration or energy stimulation. While transesophageal ...
Miracapillo Gennaro - - 2008
Cavo-tricuspid isthmus (CTI) block is currently assessed by coronary sinus (CS) pacing or low lateral and septal atrial pacing. Occasionally, CS catheterization through the femoral route can be difficult to perform or right atrial pacing can be problematic because of catheter instability or saturation of the atrial electrograms recorded near ...
Gianfranchi Lorella - - 2008
Electrical fusion between left ventricular pacing and spontaneous right ventricular activation is considered the key to resynchronisation in sinus rhythm patients treated with single-site left ventricular pacing. Use of QRS morphology to optimize device programming in patients with heart failure (HF), sinus rhythm (SR), left bundle branch block (LBBB), treated ...
Liu Chenguang C Department of Biomedical Engineering, University of Minnesota, - - 2008
A noninvasive three-dimensional (3D) cardiac electrical imaging (3DCEI) approach, which can estimate the location of the initiation site (IS) of activation and the resultant 3D activation sequence (AS) from body surface potential maps (BSPMs), was validated in an intact large mammalian model (swine) during acute ventricular pacing. Body surface potential ...
Kontogeorgis Andrianos A Leon H, Charney Division of Cardiology, Department of Medicine, New York University School of Medicine, New York, NY, USA. - - 2008
Cardiac insults such as ischemia, infarction, hypertrophy and dilatation are often accompanied by altered abundance and/or localization of the connexin43 gap junction protein, which may predispose towards arrhythmic complications. Models of chronic dyssynchronous cardiac activation have also been shown to result in redistribution of connexin43 in cardiomyocytes. We hypothesized that ...
Lopez J Alberto - - 2008
Pacing and Defibrillation Therapy. We report the successful use of a percutaneous, totally transvenous endocardial approach to atrioventricular pacing and internal cardiac defibrillation in an adult patient with tetralogy of Fallot who had undergone three previous cardiac operations, including a tricuspid valve replacement. Ventricular pacing and sensing were achieved with ...
Weber Stefan - - 2007
BACKGROUND: Microvolt T-wave alternans (MTWA) has been associated with malignant ventricular arrhythmias in patients (pts) with structural heart disease. MTWA has been shown to be a strong heart rate-dependent arrhythmia marker. However, in clinical practice some pts in which MTWA should be assessed are unable to perform physical exercise to ...
Marcus Frank I - - 2007
INTRODUCTION: Changes due to biventricular pacing have been documented by shortening of QRS duration and echocardiography. Compared to normal ventricular activation, the presence of left bundle branch block (LBBB) results in a significant change in cardiac cycle time intervals. Some of these have been used to quantify the underlying cardiac ...
Ho Reginald T - - 2007
We present a 59-year-old man with a dilated cardiomyopathy (ejection fraction = 20%), congestive heart failure and atrio-ventricular (AV) block who underwent implantation of a biventricular defibrillator (BiV ICD). While undergoing cardiac transplant evaluation for drug-refractory ventricular fibrillation, his telemetry recorded findings resembling crosstalk inhibition. Device interrogation was normal. All ...
Dzemali O - - 2007
BACKGROUND: This study investigates how different left ventricular epicardial and endocardial pacing sites influence hemodynamic performance in an animal model of heart failure (HF). METHODS: In six adult sheep, dilated HF was induced by rapid pacing. Subsequently, endocardial left ventricular stimulation was performed using a 64-electrode basket catheter. Epicardial pacing ...
Reinig Michael - - 2007
INTRODUCTION: We tested the feasibility of a new technique of direct left ventricular endocardial lead placement across the aortic valve in a chronic (six month) pig model. The potential for aortic valve damage, systemic embolization, and pacing lead maturation and function within the left ventricle are unknown. METHODS: Ten minipigs ...
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