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Results 301 - 350 of 1786
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Brace Christopher L - - 2009
PURPOSE: To compare radiofrequency (RF) ablations created by using a sequential technique to those created simultaneously by using a switching algorithm in ex vivo and in vivo liver models. MATERIALS AND METHODS: RF ablation was performed by using either sequential or switched application of three cooled electrodes in a 2-cm ...
Tiroch Klaus - - 2008
BACKGROUND: Recanalization of coronary chronic total occlusions (CTOs) remains a clinical challenge, particularly when standard guidewire attempts fail. OBJECTIVES: We sought to determine the safety and efficacy of a novel method that used high-frequency (20 kHz) vibration to fragment occlusive fibrous tissue and facilitate guidewire crossing into the distal vessel. ...
Miyagi Yasuo - - 2009
BACKGROUND: The transmurality of the ablation lesions created on a beating heart has not been examined histologically or electrophysiologically. This study aimed to assess the feasibility of an atrial epicardial or endocardial ablation in an off-pump setting using unipolar radiofrequency (RF) energy. METHODS: A linear ablation lesion of 5 cm ...
Clendenen S R - - 2008
BACKGROUND: The current means of introducing continuous sciatic catheters include nerve stimulation, with or without catheter stimulation techniques. More recently, ultrasound has been utilized to facilitate catheter placement. METHODS: This case represents a stimulating catheter-guided continuous block facilitated by three-dimensional ultrasound, which revealed aberrant anatomy with proximal and wide bifurcation ...
Kim Albert M - - 2008
BACKGROUND: Remote magnetic catheter navigation (RCN) is gaining acceptance in clinical cardiac electrophysiology, but details regarding how RCN affects procedure execution are not well characterized. METHODS: From January 1, 2005, to November 30, 2007, 721 cases were retrospectively analyzed and compared. Of these, 127 used RCN and 594 used manual ...
Lorente Leonardo - - 2008
BACKGROUND: The guidelines of the Centers for Disease Control and Prevention do not recommend the use of an antimicrobial- or antiseptic-impregnated catheter for short-term use. In previous studies, we have found a higher incidence of central venous catheter-related bacteremia among patients with femoral and central jugular accesses than among patients ...
Doll Nicolas - - 2008
PURPOSE: Recent investigations into the treatment of atrial fibrillation have suggested improved outcomes after concomitant pulmonary vein isolation (PVI) and ganglionic plexi (GP) ablation. We investigated the impact of left atrial ablation with substrate modification (left atrial maze) or epicardial PVI, combined with GP mapping and ablation, in patients with ...
Ba Maguette - - 2008
Atrial fibrillation is the most frequent form of cardiac arrhythmia. Its surgical management has improved in recent years with major advances in our knowledge of the underlying pathogenic mechanisms. This has led to simpler therapeutic strategies such as epicardial ablation. The aim of this comparative experimental study was to evaluate ...
Sakamoto Shun-ichiro - - 2008
The introduction of ablation technology has simplified surgical intervention for atrial fibrillation. However, most ablation devices cannot create focal transmural lesions on the beating heart and have difficulty ablating specific regions of the atria, such as the atrioventricular isthmus, coronary sinus, and ganglionated plexus. The purpose of this study was ...
Barley Maya E - - 2009
Accurate guidance of an ablation catheter is critical in the RF ablation (RFA) of ventricular tachycardia (VT). With current technologies, it is challenging to rapidly and accurately localize the site of origin of an arrhythmia, often restricting treatment to patients with hemodynamically stable arrhythmias. We investigated the effectiveness of a ...
Katsiyiannis William T - - 2008
Radiofrequency ablation for atrial fibrillation (AF) involves complex catheter manipulation resulting in prolonged procedure time and fluoroscopy exposure. Remote magnetic navigation (RMN) represents a novel approach toward improving the ability to perform complex ablation. Forty patients underwent ablation for AF, 20 using RMN (NIOBE II, Stereotaxis, Inc) with a 4-mm-tip ...
Yamashina Yoshihiro - - 2009
A 62-year-old-male with old inferior myocardial infarction suffered from drug resistant electrical storms and frequent shocks from an implantable cardioverter defibrillator. Emergent radiofrequency catheter ablation was performed. The patient underwent substrate mapping that uses an electro-anatomical mapping system during sinus rhythm because of multiple QRS morphologies and hemodynamic instability during ...
Sivagangabalan Gopal - - 2008
BACKGROUND: Substrate-based ablation is useful for nonhemodynamically tolerated postinfarct ventricular tachycardia. We assessed the accuracy of the CARTO contact and EnSite noncontact systems at identifying scar in a chronic ovine model with intramural plunge needle electrode recording and histological validation. METHODS AND RESULTS: Scar mapping was performed on 8 male ...
Nogami Akihiko - - 2009
We examined autopsy specimens from a patient with ischemic cardiomyopathy who underwent radiofrequency catheter ablation of ventricular fibrillation. There was site specific arrhythmogenesis of the trigger ventricular premature contractions (VPCs) and Purkinje potentials were recorded before the onset of the QRS. In postmortem examination, fibromuscular bands connecting the posterior papillary ...
Chen Jun - - 2008
Of 18,365 patients who underwent coronary angiography with a 4F or 5F universal catheter between April 2004 and May 2007, 24 (0.131%) experienced sustained ventricular tachycardia or ventricular fibrillation during the procedure. There was no significant difference in any clinical or angiographic characteristic between patients who had a ventricular arrhythmia ...
McGarvey Jeremy R - - 2008
Surgical removal or epicardial radiofrequency ablation of the left atrial appendage (LAA) is occasionally required when endocardial ablations fail. We report a modified minimally invasive surgical approach for elimination of recurrent atrial arrhythmias arising from the LAA, including both radiofrequency ablation and appendectomy. Ablation of the LAA base was performed ...
Sorajja Paul - - 2008
The objective of this study was to examine the effects of septal ablation on diastolic function with the use of invasive hemodynamics. Septal ablation is an alternative therapy for patients with obstructive hypertrophic cardiomyopathy (HCM). However, its beneficial effect on diastolic function, by relieving the systolic contraction load, may be ...
D'Avila André - - 2008
BACKGROUND: This study of a chronic porcine postinfarction model examined whether linear epicardial cryoablation was capable of creating large, homogenous lesions in regions of the myocardium including scarred ventricle. Endocardial and epicardial focal cryolesions were also compared to determine if there were significant differences in lesion characteristics. METHODS: Eighty focal ...
Asirvatham Samuel J - - 2008
Great strides have been made over the last two decades in the management of patients with rhythm disorders. Despite this, however, the remaining critical problems of stroke related to atrial fibrillation or as a result of radiofrequency ablation require innovative solutions to fully realize the potential of these recent advances. ...
Spergel Lawrence M - - 2008
The use of central venous hemodialysis catheters (CVC) continues to be high among the incident as well as the prevalent HD patients. Whereas many strategies have been implemented to decrease the use of CVCs, their placement rates have doubled since 1996. While many factors, including late referral, are responsible for ...
Maya Ivan D - - 2008
Catheter-related bacteremia is a major cause of morbidity and mortality among catheter-dependent hemodialysis patients. Microorganism biofilm matrix formation in the catheter is the pathogenic process of this entity. Administration of systemic antibiotics and removal of the offending catheter is the most logical treatment. This article discusses an alternative option, instillation ...
d'Avila Andre - - 2008
Technologic advancements have resulted in the more widespread use of catheter ablation to restore sinus rhythm in patients with atrial fibrillation (AF) and elicit improvement in symptoms, quality of life, and prognosis. However, the effectiveness of this procedure to prevent the occurrence of heart failure and stroke while reducing mortality ...
Boersma Lucas V A - - 2008
BACKGROUND: Pulmonary vein (PV) isolation for ablation of atrial fibrillation (AF) remains a complex and lengthy procedure. OBJECTIVE: The purpose of this study was to evaluate the feasibility and safety of a novel multielectrode catheter that delivers duty-cycled bipolar and unipolar radiofrequency (RF) energy. METHODS: Patients eligible for catheter ablation ...
Della Bella Paolo - - 2008
Catheter ablation of untolerated and unstable ventricular tachycardia may not be performed using a conventional activation mapping tecnique. The noncontact mapping system enables reconstruction of the spreading of activation wave through a virtually generated ventricular chamber, even from a single tachycardia beat, and was introduced as a tool to guide ...
Hasdemir Can - - 2008
A 44-year-old female undergoing radiofrequency ablation in the right ventricular outflow tract for symptomatic, frequent premature ventricular contractions developed stress cardiomyopathy (Tako-Tsubo). Stress cardiomyopathy was probably due to hyperadrenergic state induced by the procedure itself, dobutamine infusion, sympathetic nerve stimulation at the ablation site, and parasympathetic withdrawal with atropine administration.
Szilágyi Szabolcs - - 2008
AIMS: Phrenic nerve stimulation (PNS), which is often intolerable for the patient, is a known complication of resynchronization therapy. We describe a new, minimal invasive method for treating PNS. METHODS AND RESULTS: Untreatable PNS was found in nine cardiac resynchronization therapy patients with distal coronary sinus (CS) lead position 6 ...
Ghosh Subham S Cardiac Bioelectricity and Arrhythmia Center, Department of Biomedical Engineering, Washington University, St Louis, MO, - - 2008
Cardiac memory refers to a change in ventricular repolarization induced by and persisting for minutes to months after cessation of a period of altered ventricular activation (eg, resulting from pacing or preexcitation in patients with Wolff-Parkinson-White syndrome). ECG imaging (ECGI) is a novel imaging modality for noninvasive electroanatomic mapping of ...
Das Mithilesh K - - 2008
Catheter ablation is an effective therapy for symptomatic ventricular arrhythmia (VA) in patients with and without structural heart disease. It is the treatment of choice to cure or reduce recurrent VA in patients who have an implantable cardioverter defibrillator and can be a life-saving procedure in patients who have electrical ...
Ernst Sabine - - 2009
INTRODUCTION: We report on a 63-year-old female patient in whom an electrophysiologic study discovered a hemi-azygos continuation. Using the magnetic navigation system, remote-controlled ablation was performed in conjunction with the 3D electroanatomical mapping system. METHODS AND RESULTS: Failing the attempt to advance a diagnostic catheter from the femoral vein, a ...
Wirsing Melanie - - 2008
BACKGROUND: Traditionally, the positioning of central venous catheters (CVCs) outside the right atrium (RA) in patients receiving intensive care is determined by surrogate landmarks on bedside chest radiographs (CXRs). The validity of this method was examined by comparing readings of radiologists with the results of transesophageal echocardiography (TEE). METHODS: Prospective ...
Raake Philip W - - 2008
Myocardial G protein-coupled receptor kinase (GRK)2 is a critical regulator of cardiac beta-adrenergic receptor (betaAR) signaling and cardiac function. Its upregulation in heart failure may further depress cardiac function and contribute to mortality in this syndrome. Preventing GRK2 translocation to activated betaAR with a GRK2-derived peptide that binds G(beta)gamma (betaARKct) ...
Yamada Takumi - - 2008
A 31-year-old woman with idiopathic premature ventricular contractions originating from the tricuspid annulus (TA) underwent electrophysiological testing. Activation mapping with a 20-pole bipolar Halo-type catheter positioned along the TA revealed the earliest ventricular activation at a site between 7 and 8 o'clock along the TA. A reversal in the polarity ...
Efremidis Michalis - - 2008
We report on a patient with transient atrioventricular block and ST-segment elevation mimicking the ECG of myocardial infarction during transseptal puncture for radiofrequency catheter ablation of atrial fibrillation. Symptoms and EGG findings resolved spontaneously. A neurally-mediated mechanism, activated by the mechanical effects of the transseptal puncture on the interatrial septum ...
Pak Hui-Nam - - 2008
BACKGROUND: Radiofrequency catheter ablation (RFCA) targeting the left ventricular posteroseptum (LVPS) and posterior papillary muscle (PPM) terminates or prevents ventricular fibrillation (VF) in rabbit and dog hearts. However, whether the mechanism of VF maintenance is reentry or focal Purkinje firing is unclear. METHODS AND RESULTS: In the present study the ...
Dosdall Derek J - - 2008
Endocardial mapping has suggested that Purkinje fibers may play a role in the maintenance of long-duration ventricular fibrillation (LDVF). To determine the influence of Purkinje fibers on LDVF, we chemically ablated the Purkinje system with Lugol solution and recorded endocardial and transmural activation during LDVF. Dog hearts were isolated and ...
Yamada Takumi - - 2008
A 49-year-old woman with dextrocardia and situs inversus underwent catheter ablation of paroxysmal atrial fibrillation. A contrast injection into the left atrium revealed that the left atrial appendage (LAA) was adjacent to the right-sided (anatomic left) superior pulmonary vein (PV). After successful isolation of that PV, LAA potentials were recorded ...
De Sisti Antonio - - 2008
Limited information is available on the efficacy of cryoablation in the coronary venous system in humans. A patient with a lateral accessory pathway was referred to our center after several unsuccessful endocardial and epicardial (within the coronary sinus) attempts using standard radiofrequency energy. Ablation was subsequently performed successfully by applying ...
Lau Ernest W - - 2008
BACKGROUND: Guide catheters help deliver endocardial leads to specific locations within the heart, but their disengagement afterwards can be challenging. Slitting the catheter open over the lead may require the creation of an artificial platform to provide support for the blade and cause lead dislodgement through a sideways drag on ...
Hahurij Nathan D - - 2008
BACKGROUND: Fetal and neonatal atrioventricular (AV) reentrant tachycardias can be life-threatening but resolve in most cases during the first year of life. The transient presence of accessory AV myocardial connections during annulus fibrosus development may explain this phenomenon. METHODS AND RESULTS: A total of 45 human embryonic, fetal, and neonatal ...
Doppalapudi Harish - - 2008
Acute ischemia causes myriad changes including increased catecholamines. We tested the hypothesis that elevated catecholamines alone are arrhythmogenic. A 504 electrode sock was placed over both ventricles in six open-chest pigs. During control infusion of saline through a catheter in the left anterior descending coronary artery (LAD), no sustained arrhythmias ...
D'Avila Andre - - 2008
INTRODUCTION: Ablation of the mitral isthmus to achieve bidirectional conduction block is technically challenging, and incomplete block slows isthmus conduction and is often proarrhythmic. The presence of the blood pool in the coronary venous system may act as a heat-sink, thereby attenuating transmural RF lesion formation. This porcine study tested ...
Srivathsan Komandoor S - - 2008
BACKGROUND: Outflow tract ventricular tachycardia originating above the semilunar valves has been reported in a small number of studies. Discrete potentials in the great arteries (above the semilunar valves) have been rarely described in patients undergoing electrophysiology evaluation and radiofrequency ablation for ventricular arrhythmias. The mechanisms of these discrete potentials ...
Grace Andrew - - 2008
Cardiac arrhythmia management has advanced substantially and many patients are now being offered curative treatment. There is still much to do and therefore substantial research opportunities. Technical advances with better imaging and mapping datasets, improved ablation catheters and new devices to protect against SCD are all on the horizon. The ...
Patel Anshul M - - 2008
BACKGROUND: Atrial tachycardia (AT) that develops after ablation of atrial fibrillation often poses a more difficult clinical situation than the index arrhythmia. This study details the use of an impedance-based electroanatomic mapping system (Ensite NavX) in concert with a specialized multielectrode mapping catheter for rapid, high-density atrial mapping. In this ...
Yoshimachi Fuminobu - - 2008
BACKGROUND AND OBJECTIVES: Although the PercuSurge (PS) system is an efficient distal protection device, it has several limitations such as significant occlusion time causing myocardial ischemia and requirement of a large 7 or 8 Fr guiding catheter (GC). To address these problems, we developed a new method of use for ...
Mittal Suneet - - 2008
Catheter ablation has come to play an important therapeutic role in the management of some patients with ventricular arrhythmias. An important advance in catheter ablation of ventricular tachycardia (VT) has been the development of three-dimensional catheter-based mapping systems, which permit identification of the tachycardia circuit and facilitate a strategy for ...
Feld Gregory K - - 2008
BACKGROUND: Atrial flutter (AFL) is commonly treated by radiofrequency catheter ablation. Catheter-based cryoablation may be an effective alternative with potential advantages. OBJECTIVE: The purpose of this study was to study the acute and long-term safety and efficacy of catheter-based cryoablation for treatment of cavotricuspid isthmus-dependent (typical and reverse typical) AFL. ...
Aryana Arash - - 2008
Proarrhythmia is relatively common after extensive atrial ablation for atrial fibrillation, but has not been frequently documented after catheter ablation of ventricular tachycardia (VT). In theory, this phenomenon could occur if an incomplete ablation line is created between two nonconducting structures, such as dense scar or valvular annuli. This report ...
Efremidis Michalis - - 2008
Premature ventricular complex (PVC)-induced cardiomyopathy is an underappreciated cause of left-ventricular (LV) dysfunction. The present report describes the case of an elderly man with a very high burden of monomorphic PVCs and LV dysfunction. Elimination of the left ventricular focus following radiofrequency catheter ablation resulted in reversal of cardiomyopathy.
Kolditz Denise P - - 2008
BACKGROUND: The developmental mechanisms underlying the persistence of myocardial accessory atrioventricular pathways (APs) that bypass the annulus fibrosis are mainly unknown. In the present study, we investigated the role of epicardium-derived cells (EPDCs) in annulus fibrosis formation and the occurrence of APs. METHODS AND RESULTS: EPDC migration was mechanically inhibited ...
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