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Results 501 - 550 of 2019
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Heinke Matthias - - 2005
BACKGROUND: Previous studies of biventricular (BV) pacing for treatment of heart failure (HF) patients with left bundle branch block (LBBB) evaluated responders to BV pacing with acute transvenous left ventricular (LV) pacing and arterial pulse pressure (PP). The aim of this study was to assess transoesophageal LV pacing in evaluation ...
Ito Takahide - - 2005
Dual-chamber pacing reduces left ventricular (LV) outflow obstruction in patients with obstructive hypertrophic cardiomyopathy (HC), the mechanism of which lies in pacing-induced paradoxic septal motion. This study was conducted to test the hypothesis that tissue Doppler imaging (TDI) could demonstrate changes in the septal contraction sequence during dual-chamber pacing in ...
Barber Brent J - - 2005
OBJECTIVES: The purpose of this research was to assess the hemodynamic response to atrial, ventricular, and dual-chamber pacing in patients with Fontan physiology. BACKGROUND: Bradycardia, due to sinus node dysfunction or atrioventricular (AV) block, with need for pacing, is common after the Fontan operation. The optimal pacing mode for Fontan ...
Boriani Giuseppe - - 2006
BACKGROUND: In patients with severe heart failure, sinus rhythm and wide QRS complex biventricular (BiV) pacing leads to clinical and haemodynamic improvement, but the immediate reversibility of these changes is not known. METHODS: We assessed the acute and medium-term (3-month) haemodynamic effects of BiV pacing and of switching to other ...
Lucats Laurence - - 2005
Tachycardia with rapid ventricular pacing induces delayed preconditioning against arrhythmias secondary to coronary artery occlusion (CAO) and reperfusion (CAR) but its effects on myocardial stunning remains unknown. Accordingly, we investigated whether delayed preconditioning with ventricular pacing develops against myocardial stunning and whether this phenomenon is triggered by reactive oxygen species. ...
Musilli Nicola - - 2006
Evidence from randomized trials indicates that the clinical benefits of dual-chamber (DDD) pacing are modest: (i) no significant differences exist between physiological pacing and single-chamber pacing in mortality and stroke; (ii) ventricular desynchronization resulting from chronic right-ventricular pacing in DDD mode, induces a significantly increased incidence of atrial fibrillation (AF) ...
Bai Rong - - 2005
BACKGROUND: Benefits of cardiac resynchronization therapy (CRT) are well established. However, less is understood concerning its effects on myocardial repolarization and the potential proarrhythmic risk. METHODS AND RESULTS: Healthy dogs (n = 8) were compared to a long QT interval (LQT) model (n = 8, induced by cesium chloride, CsCl) ...
Dodge-Khatami Ali - - 2005
BACKGROUND: The atriopulmonary Fontan circulation leads to arrhythmias, heart failure, or protein-losing enteropathy, eventually requiring conversion. In hesitant patients, we evaluated the effect of dual chamber pacing as a time-buying measure. METHODS: Between 1997 and 2004, 9 patients (aged, 6 to 18 years) with an atriopulmonary Fontan connection and sinus ...
Melzer Christoph - - 2005
Chronotropic incompetence (CI), which has not been systematically examined in the ICD patient population, may have implications for device programming. A total of 123 ICD patients were classified into three groups: single-chamber ICD with sinus rhythm, dual-chamber ICD with sinus rhythm, and single-chamber ICD with permanent atrial fibrillation. Heart rate ...
Sakamoto Shun-Ichiro - - 2005
BACKGROUND: The atria are assumed to be connected electrically to each other at the level of the Bachmann's bundle, coronary sinus (CS) musculature, and interatrial septum, and these connections may have an important role in the interatrial conduction and perpetuation of various types of atrial tachyarrhythmias. However, the number, location, ...
Youn Ho-Joong - - 2005
BACKGROUND: This study was performed to evaluate the influence of left bundle branch block (LBBB) on left anterior descending coronary artery (LAD) flow. METHODS: We divided 89 subjects (34 males and 55 females, mean age 64 +/- 14 years) into an LBBB group (n = 40), a right ventricular (RV) ...
Dodge-Khatami Ali - - 2005
OBJECTIVE: Left heart atrial and ventricular epicardial pacing through a left lateral thoracotomy is an alternative approach for lead insertion in children, avoiding venous access complications and right ventricular stimulation, without compromising sporting or musical activities. We analyzed the survival and performance of left atrial and left ventricular epicardial pacing ...
Bruce Gregory K - - 2005
Ablation of the atrioventricular conduction system and pacemaker implantation is the preferred procedure for patients with atrial fibrillation (AF) in whom a rate control strategy has been selected but in whom rate-controlling medications are intolerable or ineffective. Selection of standard right ventricular (RV) pacing versus biventricular pacing is individualized, based ...
Raffa Santi - - 2005
We describe the case of a patient with atrioventricular (AV) junction ablation and chronic biventricular pacing in which intermittent dysfunction of the right ventricular (RV) lead resulted in left ventricular (LV) stimulation alone and onset of severe right heart failure. Restoration of biventricular pacing by increasing device output and then ...
Gimbel J Rod - - 2005
Temporary resynchronization therapy pacing is feasible, and impedance cardiography (ICG) can provide evidence of hemodynamic benefit before permanent pacemaker implantation. During an electrophysiologic study performed before permanent device implantation, a guidewire was placed in a tributary of the coronary sinus to allow pacing of the left ventricle. Temporary pacing was ...
Kato Masaya - - 2005
BACKGROUND: Although the AAI pacing mode has been shown to be electromechanically superior to the DDD pacing mode in sick sinus syndrome (SSS), there is evidence suggesting that during AAI pacing the presence of natural ventricular activation pattern is not enough for hemodynamic benefit to occur. Myocardial performance index (MPI) ...
Stöllberger Claudia - - 2005
Biventricular (BiV) pacing is a promising therapy for severe heart failure. The effect of BiV pacing is cardiac resynchronization of both ventricles. Asynchrony of the ventricular contraction and restoration of cardiac synchronization can be assessed by tissue Doppler imaging. Here we describe a patient with Becker muscular dystrophy with heart ...
Berberian George - - 2005
BACKGROUND: Temporary pacing is required after open-heart surgery for treatment of heart block. Atrioventricular delay and ventricular pacing site might be manipulated to increase cardiac output. We hypothesized that by optimizing both atrioventricular delay and ventricular pacing site a 10% improvement in cardiac output would be observed compared with a ...
Burri Haran - - 2005
BACKGROUND: Biventricular pacemakers are usually programmed with the default setting of synchronous biventricular pacing, although the ventricles may be paced sequentially. Whether this parameter is important for optimizing resynchronization therapy is not clear. OBJECTIVES: The purpose of this study was to investigate whether sequential pacing acutely improves left ventricular ejection ...
Gillis Anne M - - 2005
This article reviews controversies in cardiac pacing in four areas: methods to prevent unnecessary right ventricular pacing and optimal ventricular pacing sites in the bradycardia population, pacing for prevention of atrial fibrillation (AF), a novel pacing technique for the treatment of heart failure, and pacing for the treatment of sleep ...
Hasselman T - - 2005
Sinus node dysfunction is relatively common in patients with Fontan palliation for single ventricle congenital heart disease, and such patients often are in junctional rhythm or may have pacemaker systems for bradycardia. Because the physiologic determinants of left atrial pressure play a major role in determining pulmonary blood flow and ...
Luria David - - 2005
OBJECTIVE: In this prospective, randomized, control study we compared performance of J-shaped (JL) and straight atrial leads (SL) with active (screw-in) fixation mechanism, over a 5-year follow-up period. SUBJECTS AND METHODS: A total of 208 consecutive patients were randomized for implantation with a Medtronic 4568 JL model (n = 103) ...
Padeletti Luigi - - 2005
AIMS: In patients with atrial fibrillation right ventricular pacing can block antegrade conduction at pacing intervals longer than the shortest spontaneous R-R interval, causing the stabilization of ventricular rhythm. In this study the effects of pacing at two sites were compared in order to evaluate the role of conduction times ...
Navia José L - - 2005
Biventricular pacing is a proven advantageous adjuvant therapy for patients with ventricular dyssynchrony associated with congestive heart failure. Endocardial left ventricular lead placement does have several limitations: anatomic variations of the coronary venous system and late lead dislodgement. Epicardial lead placement is often a rescue procedure but offers some advantages ...
Sinha Anil M - - 2006
INTRODUCTION: Coronary artery disease is often accompanied with deterioration in left ventricular function. Left ventricular pacing has been shown to improve cardiac function in chronic heart failure. However, data are limited about left ventricular pacing during acute ischemia. Therefore, we studied the effects of acute myocardial ischemia on myocardial function ...
Flynn Michael J - - 2005
OBJECTIVE: In the 1990s, sequential atrio-ventricular pacing demonstrated haemodynamic benefit relative to right ventricular pacing in patients with sinus rhythm requiring pacing post cardiopulmonary bypass. The benefit of biventricular pacing has been demonstrated in non-surgical patients with severe left ventricular dysfunction. It was hypothesised that left ventricular pacing would increase ...
Chan Joseph Y S - - 2005
BACKGROUND: A nonexcitatory, nonpropagating atrial extrastimulus delivered in the refractory period of the preceding cycle can prolong the atrial effective refractory period (AERP) and prevent the induction of atrial fibrillation by another AE introduced in the vulnerable period. Whether the effect of this nonexcitatory stimulation (NE) is confined only to ...
Sweeney Michael O - - 2005
BACKGROUND: Ventricular desynchronization caused by right ventricular pacing may impair ventricular function and increase risk of heart failure (CHF), atrial fibrillation (AF), and death. Conventional DDD/R mode often results in high cumulative percentage ventricular pacing (Cum%VP). We hypothesized that a new managed ventricular pacing mode (MVP) would safely provide AAI/R ...
Sharma Arjun D - - 2005
BACKGROUND: The Dual-Chamber and VVI Implantable Defibrillator (DAVID) trial demonstrated a worse outcome in patients with implantable cardioverter-defibrillators (ICDs) programmed to DDDR at 70 bpm compared with patients who had ICDs programmed to VVI backup pacing at 40 bpm. Pacing was more frequent in the DDDR group. OBJECTIVES: The purpose ...
Eich C - - 2005
Complete heart block frequently requires emergency pacing to restore systemic perfusion. We report the case of a 3-yr-old girl undergoing interventional atrial septal defect closure who suffered from transient complete heart block with circulatory arrest. Transthoracic mechanical pacing for more than 3 min provided temporary support, sustaining an adequate cardiac ...
Lin Mao-Shin - - 2006
BACKGROUND: Despite the maintenance of atrioventricular (AV) synchrony, the detrimental effect of left ventricular asynchronization on mechanical performance and intraventricular flow by nonphysiologic right ventricular apical pacing in dual-chamber pacing, with and without rate adaptation, is not clear. METHOD: Twenty-seven consecutive patients receiving permanent pacemakers for symptomatic bradyarrhythmias (18 with ...
Thackray Simon D R - - 2006
AIMS: Different methods exist for measuring left ventricular function echocardiographically; each may be error prone due to the abnormal pattern of ventricular activation during pacing. METHODS AND RESULTS: Echocardiography was undertaken on 307 patients with permanent pacemakers; a subset of 57 underwent radionuclide ventriculography. Intrinsic and paced beats were analysed ...
Bulava Alan - - 2005
Biventricular pacing nowadays represents a recognized method of nonpharmacological treatment of severe congestive heart failure refractory to medication. A growing number of biventricular implants is likely to bring an increasing demand for the extraction of specially designed coronary sinus (CS) leads for left ventricular pacing. There is a lot of ...
Matsumoto Katsumi - - 2005
BACKGROUND: Biatrial (BiA) pacing prevents atrial fibrillation. By an unknown mechanism. The purpose of this study was to use Doppler echocardiography to evaluate the hemodynamic effects during BiA pacing. METHODS AND RESULTS: The subjects were 7 patients with bradycardia - tachycardia syndrome with an implanted pacemaker. Atrial pacing sites were ...
De Voogt Willem G - - 2005
BACKGROUND: Pacing in the low right atrial septum (LAS) appears superior to right atrial appendage or free wall stimulation for the prevention of paroxysmal atrial fibrillation. However, insertion of active fixation lead in the low right atrial septal position is difficult and time consuming, inhibiting application of this pacing method ...
Berberian George - - 2005
AIMS: A 78-year-old female with prior atrioventricular junctional ablation for paroxysmal atrial fibrillation and implantation of DDDR pacemaker underwent repair of severe tricuspid insufficiency. Effects of biventricular pacing were tested with temporary wires at the conclusion of cardiopulmonary bypass. METHODS: An ultrasonic flow probe was placed on the ascending aorta ...
Munclinger Miroslav J MJ Department of Medicine, Johannesburg Hospital, University of the Witwatersrand, - - 2005
The exact mechanisms whereby biventricular pacing enables cardiac resynchronisation are not completely understood. This study looked at the effect of biventricular pacing on interventricular asynchrony in patients submitted to biventricular pacing. A prospective series of 13 consecutive patients were selected from those referred for biventricular pacing. Criteria used included heart ...
Rothenberg Florence - - 2005
Major difficulties investigating the developing cardiac conduction system stem from that the embryonic heart is extremely small (< 2 mm) and cardiac activation is relatively rapid (< 8 msec). The objective of this study was to investigate the electrophysiology of the embryonic chick cardiac conduction system at periseptation stages with ...
Anzawa Ryuko - - 2005
Atrial pacing failure occurred after termination of atrial fibrillation by acute administration of disopyramide phosphate in a 71-year-old woman implanted with an AAI pacemaker for sick sinus syndrome. The atrial pacing threshold showed an 810% increase; however, the serum concentration of disopyramide corresponded to therapeutic level. Infusion of the same ...
Berger Thomas - - 2005
INTRODUCTION: Biventricular pacing has been shown to improve the clinical status of patients with congestive heart failure, but little is known about its influence on ventricular repolarization. The aim of our study was to evaluate the effect of biventricular pacing on ECG markers of ventricular repolarization in patients with congestive ...
Melzer Christoph - - 2005
BACKGROUND: Dual chamber pacing typically results in a high percentage of ventricular pacing. A number of studies have been conducted suggesting detrimental effects of ventricular desynchronization produced by long-term RV pacing. Pacemaker algorithms that extend the AV interval to uncover intrinsic AV conduction have been utilized to reduce ventricular pacing. ...
Boriani Giuseppe - - 2006
BACKGROUND: More information is required on the relationship between electrical and structural reverse remodeling in patients treated with cardiac resynchronization therapy. METHODS: QRS and JT intervals were investigated during different pacing modes before and 3 months after implantation of a device for biventricular (BiV) pacing in 20 patients with severe ...
Ferro Adele - - 2005
PURPOSE: 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 ...
Dixit Sanjay - - 2005
BACKGROUND: Idiopathic ventricular tachycardias (IVTs) can originate from the basal left ventricle (LV). OBJECTIVE: To determine if using magnetic electroanatomic mapping (MEAM) for accurate localization (1) unique ECG morphologies on pace maps from medial and lateral sites in basal LV could be identified and (2) this ECG information would facilitate ...
Biffi Mauro - - 2005
BACKGROUND: Devices for cardiac resynchronisation therapy (CRT) deliver energy into 3 output channels. Such a burden can significantly reduce device longevity. Autocapture has been shown to improve pacemaker longevity and safety of right ventricular pacing in clinical studies. The aim of this study was to investigate the application of Autocapture ...
Kassotis John - - 2005
The objective of this study was to assess the feasibility of DDD pacing from a standard single-pass VDD pacemaker system. Over the past 2 decades significant advances have been made in the development of single-pass VDD pacing systems. These have been shown in long-term prospective studies to effectively preserve atrioventricular ...
Porciani Maria Cristina - - 2005
In 21 patients implanted with a biventricular pacing device with programmable interventricular delay (VVd), the myocardial performance index (MPI) was evaluated during spontaneous sinus rhythm, simultaneous biventricular pacing, and sequential biventricular pacing at different VVds and atrioventricular delays (AVds). The AVd-VVd combination associated with the minimum MPI defined patient-tailored biventricular ...
Langer Frank - - 2005
BACKGROUND AND AIM OF THE STUDY: Pacing-induced mitral regurgitation contributes to the 'pacemaker syndrome', which usually is observed with ventricular (V) pacing, but has also been reported with atrioventricular (AV) sequential pacing. Effects of different pacing modes on 3-D kinematics of the mitral apparatus are incompletely understood. METHODS: Radio-opaque markers ...
Sambuceti Gianmario - - 2005
The classical model of coronary physiology implies the presence of maximal microcirculatory vasodilation during myocardial ischemia. However, Doppler monitoring of coronary blood flow (CBF) documented severe microcirculatory vasoconstriction during pacing-induced ischemia in patients with coronary artery disease. This study investigates the mechanisms that underlie this paradoxical behavior in nine patients ...
Kurisu Satoshi - - 2005
A-55-year-old man with diabetes mellitus was admitted to hospital because of chest pain. He was diagnosed as anterior acute myocardial infarction and treated with stent placement. After 7 days, ventricular fibrillation occurred because of a subacute reocclusion and balloon angioplasty was performed. Despite reperfusion therapy, intraaortic balloon pumping, antiarrhythmic drugs ...
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