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Results 451 - 500 of 1049
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Walsh Sj S j - - 2003
BACKGROUND: We investigated a novel device that delivered biphasic and monophasic shocks without tilt, in transvenous cardioversion of atrial fibrillation (AF). The device contains a radiofrequency (RF) transmitting primary, a 15mm air gap and a passive secondary unit that produces the required direct current waveform. METHODS: The device was assessed ...
Marenco John P - - 2003
INTRODUCTION: Previous studies using various bipolar pacemaker leads have shown that the AutoCapture (AC) Pacing System is able to verify ventricular capture and regulate pacing output, increasing patient safety with respect to unexpected threshold changes and potentially prolonging device longevity. An increasing number of patients with implantable cardioverter defibrillators (ICDs) ...
Liu Brant C - - 2003
In the United States, physicians adapt currently available defibrillators to accommodate leads for biventricular pacing in those congestive heart failure patients who might benefit from cardiac resynchronization and who are additionally at risk for sudden cardiac death. The adaptation of the lead system of available defibrillators to also allow them ...
Srivathsan Komandoor - - 2003
A 53-year-old man with nonischemic cardiomyopathy underwent implantation of a biventricular implantable cardioverter defibrillator (ICD) for symptomatic ventricular tachycardia. He received five shocks while attempting to exercise, 48 hours after implantation. Interrogation of the device revealed double counting of ventricular sensed events by the left and right ventricular leads. Shortening ...
Tse Hung-Fat - - 2003
INTRODUCTION: Previous studies have demonstrated significant failure in converting atrial fibrillation (AF) using a conventional ventricular pathway. The aim of this study was to assess the benefit of incorporating a coronary sinus (CS) lead into the atrial defibrillation pathway in atrial defibrillation threshold (ADFT) reduction in patients with persistent AF. ...
Jenkins Janice M - - 2003
Ann Arbor Electrogram Libraries (AAEL) is a database of over 500 electrocardiographic recordings made during clinical electrophysiology studies over a period of 15 years. These data are used by university researchers and cardiac device research and development laboratories to develop and test arrhythmia detection algorithms. The AAEL library is in ...
Knaggs A L - - 2002
Revision open heart surgery may be impeded by a dense network of pericardial adhesions rendering cardiac mobilization laborious or incomplete, and internal defibrillation impossible. External defibrillation, the current alternative to internal defibrillation, may result in myocardial stunning secondary to the delivery of escalating, monophasic, high-energy shocks. Automated external defibrillation, by ...
Moss Arthur J - - 2002
The MADIT-II trial showed that in patients with a prior myocardial infarction and ejection fraction </=0.30, prophylactic implantation of a defibrillator improves survival with a 31% reduction in mortality during an average follow-up of 20 months. Electrophysiologic inducibility was positive in 36% of patients at the time of ICD implantation. ...
Fenelon Guilherme - - 2002
OBJECTIVES: In cellular studies, ventricular refractoriness (ERP) is prolonged in heart failure (CHF), but clinical evidence is lacking. The average ventricular fibrillation cycle length (VFCL) has been shown to correlate with local ERP. We hypothesized that the VFCL increases with left ventricular (LV) dysfunction. Therefore, we evaluated intracardiac VFCL recorded ...
Tang Wanchun - - 2002
OBJECTIVE: For adults, 150-J fixed-energy, impedance-compensating biphasic truncated exponential (ICBTE) shocks are now effectively used in automated defibrillators. However, the high energy levels delivered by adult automated defibrillators preclude their use for pediatric patients. Accordingly, we investigated a method by which adult automated defibrillators may be adapted to deliver a ...
White Roger D - - 2002
The transition of biphasic waveforms from ICDs to external defibrillators constitutes a significant technological advances for transthoracic defibrillation. Impedance compensation has enabled the delivery of defibrillating current adapted to each patient and each shock in the same patient. Optimally designed biphasic waveforms have been shown clinically to have greater efficacy ...
Caffrey Sherry L - - 2002
BACKGROUND: Automated external defibrillators save lives when they are used by designated personnel in certain public settings. We performed a two-year prospective study at three Chicago airports to assess whether random bystanders witnessing out-of-hospital cardiac arrests would retrieve and successfully use automated external defibrillators. METHODS: Defibrillators were installed a brisk ...
Garg Ashok - - 2002
Implantable cardioverter defibrillators (ICDs) are now an accepted and effective therapy for treatment of survivors of sudden cardiac death (SCD) and prevention of SCD in high-risk patients. Normal ICD function and delivery of therapy depends on appropriate sensing and detection of myocardial electrical potentials. Electromagnetic interference resulting in ICD malfunction ...
Zaim S - - 2002
We describe a patient who presented with high rate ventricular pacing secondary to dysfunction of his implantable cardioverter defibrillator (ICD). The device was also unable to communicate with the programmer and unable to treat ventricular fibrillation. Immediate disconnection of the ICD from the leads was the only effective recourse. Subsequent ...
Takahashi Tamana - - 2002
Recently, the routine use of dual-chamber implantable cardioverter defibrillators (DC-ICD) has been advocated over the single-chamber version (SC-ICD), but there are few reports of the frequency of complications between the 2 types of ICDs. Between July 1997 and April 1999, 178 consecutive patients underwent implantation of either a transvenous SC-ICDs ...
Lee Kerry L - - 2002
BACKGROUND: The Multicenter Unsustained Tachycardia Trial (MUSTT) was designed to evaluate an antiarrhythmic treatment strategy, including drugs and implantable defibrillators (ICDs), guided by electrophysiological (EP) testing. We performed several statistical analyses to assess the contribution of defibrillators to the observed treatment benefit. METHODS AND RESULTS: First, the effects of defibrillators ...
Kanagaratnam Logan - - 2002
Biventricular ICDs may offer increased benefit for patients with severe congestive heart failure and ventricular arrhythmia. Currently there are no approved dedicated biventricular ICDs available. Twenty-one consecutive patients who had approved nondedicated hardware implanted for biventricular pacing and defibrillation were included in this study. All device therapies were evaluated using ...
Jongnarangsin Krit - - 2002
A 71-year-old patient underwent routine single-chamber implantable cardioverter defibrillator (ICD) generator replacement. During defibrillation threshold testing, ventricular tachycardia was induced but the ICD failed twice to properly detect the tachycardia due to endocardial R wave alternans and sensing of every other beat. The problem was resolved by inserting a separate ...
Telfer Edward A - - 2002
De novo postoperative life-threatening ventricular arrhythmias are poorly understood. Long-term benefits of, and need for, treatment is uncertain. To assess the therapeutic advantage of ICD to manage new-onset, life-threatening ventricular tachyarrhythmias after cardiac surgery. Patients included were those with an ICD implanted for de novo life-threatening ventricular tachyarrhythmias encountered 48 ...
Saxon Leslie A - - 2002
BACKGROUND: Recently completed studies have evaluated the role of the Implantable Cardioverter Defibrillator (ICD) in extending life in the letting of left ventricular dysfunction. METHODS AND RESULTS: All major primary prevention ICD trials performed in the United States are reviewed. CONCLUSIONS: Data to date supports the use of the ICD ...
Eftestøl Trygve - - 2002
BACKGROUND: Cardiopulmonary resuscitation (CPR) creates artifacts on the ECG and, with automated defibrillators, a pause in CPR is mandatory during rhythm analysis. The rate of return of spontaneous circulation (ROSC) is reduced with increased duration of this hands-off interval in rats. We analyzed whether similar hands-off intervals in humans with ...
Kose Sedat - - 2002
Ventricular fibrillation in a patient with ventricular preexcitation is usually due to atrial fibrillation with an extremely rapid ventricular rate from which it degenerates. We present a case with Wolff-Parkinson-White syndrome and coexistent idiopathic ventricular fibrillation. The patient, a 23-year-old male, had had a cardiac arrest four years earlier. In ...
Sorbera Carmine A - - 2002
The implantable cardioverter defibrillator (ICD) is now an integral therapy for cardiac patient care. More than 20 years have passed since the first ICD implant. Sudden cardiac death from arrhythmia (ventricular tachycardia and fibrillation) has been significantly decreased because of the use of ICD therapy. Primary treatment trials have shown ...
Eason James - - 2002
Finite element modelling of the heart for the purpose of studying the electric fields of defibrillation shocks requires knowledge of the geometry of the heart during fibrillation. However, the standard method of measuring this geometry, MRI. cannot be used during fibrillation because the heart geometry changes rapidly and perhaps unpredictably. ...
Gold Michael R - - 2002
INTRODUCTION: Atrial defibrillation can be achieved with standard implantable cardioverter defibrillator leads, which has led to the development of combined atrial and ventricular devices. For ventricular defibrillation, use of an active pectoral electrode (active can) in the shocking pathway markedly reduces defibrillation thresholds (DFTs). However, the effect of an active ...
Pellis Tommaso - - 2002
The new Guidelines of the American Heart Association state that lay rescuers can no longer rely on the manual pulse check to confirm cardiac arrest in an unresponsive patient. We were therefore prompted to develop a method for automated determination of the presence or absence of cardiac contraction and breathing. ...
Wann Shue-ren SR - - 2002
Ventricular fibrillation (VF) is generally sustained. The mechanism is, at least in part, caused by progressive accumulation of intracellular sodium and calcium ions during untreated ventricular fibrillation, which subsequently increases defibrillation threshold. Cariporide, a potent and specific inhibitor of the sodium-hydrogen exchanger, has been shown to reduce intracellular sodium and ...
Moss Arthur J - - 2002
BACKGROUND: Patients with reduced left ventricular function after myocardial infarction are at risk for life-threatening ventricular arrhythmias. This randomized trial was designed to evaluate the effect of an implantable defibrillator on survival in such patients. METHODS: Over the course of four years, we enrolled 1232 patients with a prior myocardial ...
Haïssaguerre Michel - - 2002
Ventricular fibrillation is the main mechanism of sudden cardiac death, but the source of its spontaneous initiation has not been mapped. 16 patients were investigated by electrography and radiofrequency ablation after resuscitation from recurrent idiopathic ventricular fibrillation. Triggers of ventricular fibrillation originated from various locations within the Purkinje system in ...
Colquhoun M C - - 2002
OBJECTIVE: To investigate the mode of cardiac arrest in patients with acute myocardial infarction attended by general practitioners, and the effectiveness of early defibrillation. DESIGN: Retrospective observational study. SETTING: British general practice. PARTICIPANTS: General practitioners equipped with defibrillators by the British Heart Foundation. MAIN OUTCOME MEASURES: Cardiac rhythm when first ...
Walcott Gregory P - - 2002
OBJECTIVES: The goal of this study was to determine if the defibrillation threshold (DFT) after spontaneous ventricular fibrillation (VF) secondary to acute ischemia differs from the DFT for electrically induced VF in the absence of ischemia in anesthetized, closed-chest dogs and pigs. BACKGROUND: The efficacy of external defibrillators has been ...
Swygman Craig - - 2002
Implantable cardioverter defibrillators (ICDs) have become an important therapeutic modality for patients who have had a cardiac arrest or are at risk for life-threatening ventricular arrhythmias. Clinical trials have confirmed the role of the ICD for patients with sustained ventricular arrhythmias and have expanded the indications to include patients with ...
Coats Andrew J S - - 2002
In a press conference on Nov. 20, 2001 it was announced that the Multi-center Autonomic Defibrillator Implantation Trial II (MADIT II) was stopped early because of a 30% reduction in mortality in patients randomised to receive an implantable defibrillator device. The 4 year multi-centre trial of 1200 patients was terminated ...
Steinbeck Gerhard - - 2002
INTRODUCTION: The rate of implantation of implantable cardioverter defibrillators (ICD) is growing much faster in the United States than in western Europe. Among several factors, education and awareness of the problem of sudden cardiac death might account for this discrepancy. METHODS AND RESULTS: Guidelines for ICD implantation developed in the ...
Gradaus Rainer - - 2002
Early during ventricular fibrillation, the defibrillation threshold may be low, as ventricular fibrillation most probably arises from a localized area with only a few wavefronts and the effects of global ischemia, ventricular dilatation, and sympathetic discharge have not yet fully developed. The purpose of this study was to explore the ...
Koster Rudolph W - - 2002
INTRODUCTION: Sudden cardiac death is a major health problem. Worldwide success of resuscitation from out-of-hospital cardiac arrest is modest, with 5% to 10% survival to hospital discharge. METHODS AND RESULTS: In the chain of survival, early defibrillation (goal <5 min after collapse) is a major determinant of successful outcome of ...
Boriani Giuseppe - - 2002
The role of devices that deliver shock therapy for atrial fibrillation is still debated. Following technical improvements in catheter-based atrial defibrillation, implantable devices have become available either in the form of stand-alone atrial defibrillators or in the form of dual defibrillators. Although preliminary results do not support their use as ...
Lüderitz B - - 2002
The history of cardiac rhythm disorders including antiarrhythmic drugs and electrotherapeutical tools is long and fascinating. In the beginning, there was not simply the anatomy and physiology of the heart, but also analysis of the pulse, which indicates the activity of the heart. Thus, like any other field of medicine, ...
Marketou M E - - 2001
For a patient with idiopathic dilated cardiomyopathy, an implantable defibrillator, and amiodarone induced thyrotoxicosis associated with ventricular fibrillation storm. Medical therapy was ineffective. Thyroidectomy resulted in immediate control of the arrhythmia and permitted reinitiation of amiodarone. At 18-month follow-up, the patient remained euthyroid on amiodarone and ventricular arrhythmia free.
Wang Y - - 2001
Finite-element (FE) modeling has been widely used in studies of bioelectric phenomena of tissues, including ventricular defibrillation. Most FE models, whether built from anatomical atlases or subject-specific tomographic images, treat the myocardium as an isotropic tissue. However, myocardium has been experimentally shown to have significant anisotropy in its resistivities, although ...
Favale S - - 2001
The "EGM width criterion" is a discrimination algorithm that was available in the last generation ICDs. It improved ventricular tachycardia detection by withholding inappropriate therapy deliveries in the presence of narrow QRS tachycardias. The accuracy of the algorithm depends on the optimal settings of the intracardiac EGM source, the "slew ...
Butter C - - 2001
BACKGROUND: Defibrillation thresholds (DFT) with standard implantable cardioverter-defibrillator leads in the right ventricle (RV) may be determined by weak shock field intensity in the myocardium of the left ventricle (LV). Adding a shocking electrode in a coronary vein on the middle of the LV free wall, thereby establishing biventricular defibrillation, ...
Sanders G D - - 2001
BACKGROUND: Clinical trials have shown that implantable cardioverter defibrillators (ICDs) improve survival in patients with sustained ventricular arrhythmias. OBJECTIVE: To determine the efficacy necessary to make prophylactic ICD or amiodarone therapy cost-effective in patients with myocardial infarction. DESIGN: Markov model-based cost utility analysis. DATA SOURCES: Survival, cardiac death, and inpatient ...
Achleitner U - - 2001
BACKGROUND AND OBJECTIVE: Chest compressions before initial defibrillation attempts have been shown to increase successful defibrillation. This animal study was designed to assess whether ventricular fibrillation mean frequency after 90 s of basic life support cardiopulmonary resuscitation (CPR) may be used as an indicator of coronary perfusion and mean arterial ...
Michaud G F - - 2001
According to American Heart Association/American College of Cardiology Practice Guidelines, electrolyte abnormalities, including abnormal serum potassium concentrations, are considered a correctable cause of a life-threatening ventricular arrhythmia. Ventricular defibrillator therapy in this situation is a class III indication, and thought to be ineffective and perhaps harmful, although there are minimal ...
Patwardhan A - - 2001
Cycle periods in ECG during VF are correlated with periods of reentrant activation. The ECGs recorded from different locations on the thorax were contributed to from electrical activations within the heart in approximately inverse proportion of their distance from the recording sites. Similarity in cycle periods between ECGs recorded from ...
Merkely B - - 2001
One of the most important subsystems of implantable cardioverter defibrillator (ICD) is the sensing stage, since it determines the sensitivity and specificity of the device to detect the heart rate and the underlying arrhythmia. This paper aims to investigate a new detection algorithm for ICD, which operates fully automatically. The ...
Hamprecht F A - - 2001
BACKGROUND: Noninvasive prediction of defibrillation success after cardiac arrest and cardiopulmonary resuscitation (CPR) may help in determining the optimal time for a countershock, and thus increase the chance for survival. METHODS: In a porcine model (n=25) of prolonged cardiac arrest, advanced cardiac life support was provided by administration of two ...
Tang W - - 2001
STUDY OBJECTIVE: To compare the effects of biphasic defibrillation waveforms and conventional monophasic defibrillation waveforms on the success of initial defibrillation, postresuscitation myocardial function, and duration of survival after prolonged duration of untreated ventricular fibrillation (VF), including the effects of epinephrine. DESIGN: Prospective, randomized, animal study. SETTING: Animal laboratory and ...
Panchal V R - - 2001
A 70-year-old man with a single-chamber implantable cardioverter defibrillator (ICD) placed for ventricular tachycardia presented with syncope. He was found to have ventricular flutter/fibrillation with capacitor charge time in excess of 1 minute before defibrillation. The excessive charge time was secondary to ICD capacitor malfunction. The generator was explanted and ...
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