Search Results
Results 701 - 750 of 1461
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Yashima M - - 2000
The vulnerability of the infarcted hearts to ventricular fibrillation (VF) was tested in in situ canine hearts during nicotine infusion. The activation pattern was mapped with 477 bipolar electrodes in open-chest anesthetized dogs (n = 8) 5-6 wk after permanent occlusion of the left anterior descending coronary artery. Nicotine (129 ...
Narayan S M - - 2000
OBJECTIVES: We sought to study the effect of heart rate acceleration and deceleration on the ability of repolarization alternans (RPA) to stratify ventricular tachycardia (VT) risk. BACKGROUND: Heart rate fluctuations alter arrhythmic propensity, yet it is unclear whether fluctuations, as well as absolute rate, dynamically increase VT risk. We hypothesized ...
Greene H L - - 2000
Ventricular arrhythmias remain a major cause of cardiovascular mortality. Therapy for serious ventricular arrhythmias has evolved over the past decade, from treatment primarily with antiarrhythmic drugs to implanted devices. The implantable cardioverter-defibrillator (ICD) is the best therapy for patients who have experienced an episode of ventricular fibrillation not accompanied by ...
Hoppe U C - - 2000
Evidence suggests that infarct related artery (IRA) patency may improve survival after acute myocardial infarction, which is thought to be partially due to a lower incidence of malignant ventricular tachyarrhythmias. However, little is known about the effect of IRA patency on antiarrhythmic drug response and long-term outcome in patients with ...
Sosa E - - 2000
OBJECTIVES: We sought to evaluate feasibility, safety and results of transthoracic epicardial catheter ablation in patients with ventricular tachycardia occurring late after an inferior wall myocardial infarction. BACKGROUND: Transthoracic epicardial catheter ablation effectively controls recurrent ventricular tachycardia (VT) in patients with Chagas' disease in whom epicardial circuits predominate. Epicardial circuits ...
Chinushi M - - 2000
To study the role of antitachycardia burst pacing in patients with reentrant pleomorphic ventricular tachycardia (VT) associated with non-coronary artery diseases, the efficacy of antitachycardia pacing and appropriate antitachycardia pacing cycle length were evaluated in each pleomorphic VT morphology of seven patients. Seven patients were included in this study. Clinically ...
Chorro F J - - 2000
BACKGROUND: The purpose of this study was to determine whether the myocardial electrophysiological properties are useful for predicting changes in the ventricular fibrillatory pattern. METHODS AND RESULTS: Thirty-two Langendorff-perfused rabbit hearts were used to record ventricular fibrillatory activity with an epicardial multiple electrode. Under control conditions and after flecainide, verapamil, ...
Kim U K - - 2000
Mitochondrial DNA (mtDNA) mutations are not only responsible for organ dysfunction due to inefficient energy production but also indicators of metabolic and functional stresses in the organ. To analyze the significance of deletion mutation in human myocardium, we screened the presence of two common deletions (7.4 kb from 8637-16084 nt, ...
Couderc J P - - 2000
BACKGROUND: Late potentials (LPs) in the terminal portion of the QRS complex are commonly sought to identify post-myocardial infarction patients prone to ventricular tachyarrthythmias (VT) or sudden death. More recent time frequency signal processing tools have been shown to provide new parameters for the quantification of LPs and abnormal activities ...
Ramanna H - - 2000
A 61-year-old woman with dilated cardiomyopathy, who previously underwent successful radiofrequency catheter ablation for atrial flutter, developed monomorphic ventricular tachycardia (VT). The site of VT origin was the inferobasal right ventricle adjacent to the previous atrial isthmus ablation area. The most likely mechanism for the VT was scar-related reentry, the ...
Korhonen P - - 2000
INTRODUCTION: Magnetocardiographic (MCG) mapping is a new method to record cardiac signals. This study examined the association of MCG late fields with the propensity to sustained ventricular tachycardia (VT) after myocardial infarction (MI). METHODS AND RESULTS: One hundred patients with remote MI were studied, 38 with and 62 without history ...
Washizuka T - - 2000
In idiopathic left ventricular tachycardia (ILVT), the reentrant circuit is considered to involve the Purkinje system, and the Purkinje potential (P-potential) appears to be a marker for successful ablation. However, the characteristics of the reentrant circuit in ILVT have not yet been defined. In 2 cases of ILVT, we performed ...
Zaitsev A V - - 2000
Tissue heterogeneities may play an important role in the mechanism of ventricular tachycardia (VT) and fibrillation (VF) and can lead to a complex spatial distribution of excitation frequencies. Here we used optical mapping and Fourier analysis to determine the distribution of excitation frequencies in >20 000 sites of fibrillating ventricular ...
Saeed M - - 2000
Ventricular tachycardia (VT) initiation and its relation to various clinical factors was studied by reviewing intracardiac electrograms from patients with implantable cardioverter-defibrillators. Events were divided into (1) sudden onset without preceding ventricular premature complexes (VPCs), (2) extrasystolic onset with VPCs, or (3) paced, depending on the type and morphology of ...
Menon V - - 2000
BACKGROUND AND HYPOTHESIS: The implantable cardioverter defibrillator (ICD) is the best available strategy to protect patients from life-threatening ventricular arrhythmia. Although unproven, it is commonly utilized to treat subjects with syncope, a negative clinical workup, structural heart disease, and inducible sustained monomorphic ventricular tachycardia (VT) on programmed electrophysiologic stimulation (EPS). ...
Kondo K - - 2000
Ventricular tachycardia (VT) in coronary artery disease arises mostly from endocardial sites. However, little is known about the site of origin in other diseases. We report two patients who had VT originating from an anterior aspect of the left ventricle just below the mitral annulus, adjacent to the left ventricular ...
Yoshida Y - - 2000
BACKGROUND: Intracellular calcium overload is believed to play an important role in development of reperfusion arrhythmias. Dipyridamole, an inhibitor of cellular uptake of adenosine, may prevent or terminate reperfusion arrhythmias by reducing intracellular calcium overload. METHODS AND RESULTS: First, we tested for a preventive effect of dipyridamole. Sixty-one patients who ...
Lerner D L - - 2000
BACKGROUND: Myocardial ischemia causes profound changes in both active membrane currents and passive electrical properties. Because these complex changes develop and progress concomitantly, it has not been possible to elucidate the relative contributions of any one component to arrhythmogenesis induced by acute ischemia. Cx43+/- mice express 50% of the normal ...
Chiladakis J A - - 2000
We investigated the clinical significance and mechanism of the R-on-T phenomenon in the current thrombolytic era as potential precipitant of R-on-T-induced early ventricular tachyarrhythmias in patients with a thrombolysed acute myocardial infarction. We also examined the role of QT dispersion on ventricular vulnerability and its association with R-on-T-initiated ventricular tachyarrhythmias. ...
Naccarelli G V - - 2000
Amiodarone is an antiarrhythmic agent commonly used in the treatment of supraventricular and ventricular tachyarrhythmias. This paper reviews clinical trials in which amiodarone was used in one of the treatment arms. Key post-myocardial infarction trials include EMIAT and CAMIAT, both of which demonstrated that amiodarone reduced arrhythmic but not overall ...
Callaway C W - - 2000
Ventricular fibrillation (VF) is the most common arrhythmia causing sudden cardiac death. However, the likelihood of successful defibrillation declines with increasing duration of VF. Because the morphology of the electrocardiogram (ECG) waveform during VF also changes with time, this study examined a new measure that describes the VF waveform and ...
Wang X - - 2000
We studied the relationship between the spatial distribution of late potentials (LPs) and the origin of premature ventricular complexes (PVCs) using body surface maps in 55 patients with postinfarction sustained ventricular tachycardia (VT). Body surface maps were recorded from 87 leads to construct departure maps during sinus rhythm and signal-averaged ...
Ellison K E - - 2000
INTRODUCTION: Hemodynamic collapse precludes extensive catheter mapping to identify focal target regions in many patients with ventricular tachycardia (VT) associated with heart disease. This study tested the feasibility of catheter ablation of poorly tolerated VTs by targeting a region identified during sinus rhythm. METHODS AND RESULTS: Ablation was attempted in ...
Kusano K F - - 2000
We describe a patient with arrhythmogenic right ventricular cardiomyopathy in whom ventricular tachycardia (VT) was ablated by isolating a relatively large area of the critical site using catheter ablation. Endocardial mapping showed abnormal fragmented electrograms with delayed potential (DP) from an entire area of the aneurysm. Pace mappings from the ...
Krebs M E - - 2000
INTRODUCTION: Ablation of ventricular tachycardia (VT) arising from the right ventricular outflow tract (RVOT) has proven highly successful, yet VTs with similar ECG features may originate outside the RVOT. METHODS AND RESULTS: We reviewed the clinical, echocardiographic, and ECG findings of 29 consecutive patients referred for ablation of monomorphic VT ...
Shiraishi H - - 2000
Myotonic dystrophy (MD) is characterized by myotonia and muscular dystrophy and cardiac involvement with tachy-arrhythmia is rarely encountered. We report a case of MD complicated with severe left ventricular hypofunction and incessant ventricular tachycardia (VT) with varying heart rates. The morphology of VT suggested that it originated from the right ...
Wessel N - - 2000
Ventricular tachycardia or fibrillation (VT-VF) as fatal cardiac arrhythmias are the main factors triggering sudden cardiac death. The objective of this study is to find early signs of sustained VT-VF in patients with an implanted cardioverter-defibrillator (ICD). These devices are able to safeguard patients by returning their hearts to a ...
Brembilla-Perrot B - - 2000
The Multicenter Automatic Defibrillator Implantation Trial (MADIT) has recently confirmed the role of programmed ventricular stimulation (PVS) to identify the high risk patients of sudden death after myocardial infarction and to prevent this risk. The purpose of this study was to evaluate the long-term reproducibility of PVS in these patients. ...
Yoshida Y - - 1999
Radiofrequency catheter ablation guided by pace-mapping techniques has proven effective in eliminating idiopathic ventricular tachycardia (VT) originating from the right ventricular outflow tract (RVOT). A method for rapidly identifying the origin of VT from 12-lead electrocardiogram (ECG) findings would be helpful for the catheter ablation procedure. The purpose of this ...
Nemec J - - 1999
Patients with heart disease and decreased heart rate variability (HRV) have an increased risk of all-cause mortality as well as arrhythmic death. The question of acute changes in HRV immediately preceding arrhythmic events remains unanswered. We analyzed data from patients with implantable cardioverter defibrillators who had ventricular tachycardia (VT) or ...
Hohnloser S H - - 1999
The implantable cardioverter defibrillator (ICD) protects patients from sudden cardiac death due to ventricular tachyarrhythmias. The capability of an improved overall survival of high-risk patients in comparison to the best pharmacologic therapy has been evaluated over the last few years in prospective randomized trials. In patients with a history of ...
Angelos M G - - 1999
STUDY OBJECTIVE: We sought to determine whether flow rates of approximately 60% of normal values are sufficient to preserve the left ventricular myocardial high-energy phosphate pool during ventricular fibrillation (VF). METHODS: Mixed-breed swine (weight 22. 4+/-2.5 kg) were anesthetized with alpha-chloralose, placed in a state of VF, and perfused with ...
Greenspon A J - - 1999
INTRODUCTION: Accurate analysis of the arrhythmia substrate is important for successful radiofrequency ablation of sustained ventricular tachycardia (VT) after myocardial infarction (MI). METHODS AND RESULTS: A multielectrode "basket" catheter capable of endocardial recording and pacing was inserted percutaneously into the left ventricle of post-MI swine for analysis of the mechanism ...
Johnson R G - - 1999
OBJECTIVE: To determine whether a correlation exists between concentrations of intracellular and extracellular potassium and to determine the frequency of ventricular ectopy in patients after cardiac operations. DESIGN: Prospective, observational clinical evaluation. SETTING: Surgical-respiratory intensive care unit of a university-affiliated tertiary care center. PATIENTS: Continuous 24-hr electrocardiographic monitoring was performed, ...
Fan K - - 1999
Dual chamber ICD capable of providing dual chamber pacing (DDD) and ventricular arrhythmia therapy is now available. We report our experience of clinical performance of dual chamber ICDs amongst Chinese population.METHODS: 9 patients (6 men and 3 women) received dual chamber ICDs, mean age 50 +/- 18.8 years. The indications ...
Kudenchuk P J - - 1999
Antiarrhythmic drugs currently recommended in the American Heart Association's Advanced Cardiac Life Support (ACLS) guidelines for the treatment of cardiac arrest have not been proved in controlled clinical trials to improve survival in patients with ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT). Intravenous amiodarone is a promising agent for ...
Kim Y H - - 1999
BACKGROUND: The role of papillary muscle (PM) in the generation and maintenance of reentry is unclear. METHODS AND RESULTS: Computerized mapping (477 bipolar electrodes, 1.6-mm resolution) was performed in fibrillating right ventricles (RVs) of swine in vitro. During ventricular fibrillation (VF), reentrant wave fronts often transiently anchored to the PM. ...
Baker K E - - 1999
The platelet-activating factor (PAF) antagonist BN-50739 can suppress certain cardiac arrhythmias. PAF is released from ischaemic myocardium and may contribute to initiation of ischaemia-induced ventricular fibrillation (VF). In this study we characterised the action of BN-50739 on left regional ischaemia-induced VF and examined whether effects are mediated within the ischaemic ...
Washizuka T - - 1999
A 72-year old male with an old myocardial infarction who had drug-refractory ventricular tachyarrhythmias received an implantable cardioverter-defibrillator (ICD). The patient did not take his prescribed beta-blocking agent for two days, following which he experienced six discrete shocks for spontaneous VT while riding his bicycle. Both 5J and 30J cardioversions ...
Komori S - - 1999
The antiarrhythmic effect of magnesium sulfate (Mg) as well as the hemodynamics were studied using the coronary ligation and reperfusion models in rats. In the study on coronary ligation arrhythmia, i.v. administration of Mg (0.6, 2, 6, 20 and 60 micromol) was conducted at 5 min after coronary ligation. Mg ...
Gazmuri R J - - 1999
OBJECTIVE: Ventricular fibrillation (VF) is known to increase myocardial oxygen requirements and to alter coronary vascular physiology. However, the significance of these effects during cardiac arrest and resuscitation is not well understood. A model was developed in the isolated rat heart to investigate the myocardial effects of VF during a ...
Sra J - - 1999
SCD continues to be an important cause of death and morbidity. Despite expanding insight into the mechanisms causing SCD, the population at high risk is not being effectively identified. Although there is still much to do in the management phase of SCD (predicting the efficacy of various therapies), recent clinical ...
Joglar JA - - 1999
The approach to patients with symptomatic ventricular tachycardia (VT) depends on the presence and type of structural heart disease. In patients with underlying heart disease and ventricular fibrillation or sustained symptomatic VT with hemodynamic compromise, the implantable cardioverter-defibrillator (ICD) is superior to antiarrhythmic drugs for the improvement of overall survival. ...
Alexander M E - - 1999
INTRODUCTION: The role of programmed ventricular stimulation (VSTIM) for risk stratification in congenital heart disease is unclear. We analyzed the results of VSTIM in selected congenital heart disease survivors at a single center to determine whether it improved the ability to predict a serious outcome. METHODS AND RESULTS: Between July ...
Rankovic V - - 1999
INTRODUCTION: Although premature beats originating in areas of ischemia have been shown to be important in initiating ventricular fibrillation (VF), the participation of the ischemic zone in maintenance of VF has not been investigated. METHODS AND RESULTS: Ten normal dogs underwent induction of two separate episodes of VF, before and ...
Shimoike E - - 1999
There have been several reports with respect to idiopathic ventricular tachycardias (VTs) originating from the left ventricular outflow tract (LVOT). A previous report suggested that triggered activity plays a partial role in idiopathic LVOT tachycardia from the electrophysiological as well as the electropharmacological viewpoint. However, the exact role of triggered ...
Kocovic D Z - - 1999
OBJECTIVES: The purpose of this study was to determine the relation of isolated potentials (IPs) recorded during ventricular tachycardia (VT) to reentry circuit sites identified by entrainment. BACKGROUND: Reentry circuits causing VT late after myocardial infarction are complex. Both IPs and entrainment have been useful for identifying successful ablation sites, ...
Lacroix D - - 1999
Ventricular tachycardia (VT) substrates may form in preferential locations and similar electrocardiographic patterns may be observed when ventricular activation starts from a particular site. We examined the role of the posterior inferior process of the left ventricle in the mechanism of VT occurring after inferior wall myocardial infarction. We reviewed ...
Chinushi M - - 1999
A 33 year-old woman was referred to our hospital for further treatment of ventricular tachycardia (VT). During treatment with amiodarone (200 mg/day), clinical VT at the cycle length of 510 ms was induced. During the VT, rapid ventricular pacing was repeated at progressively shorter cycle lengths after a decrement of ...
Jalife J - - 1999
Ventricular fibrillation (VF) is the leading heart rhythm alteration that results in sudden cardiac death, yet the detailed mechanisms of the arrhythmia remain elusive. Fibrillation has been defined as "turbulent" cardiac electrical activity, which conjures up the idea of totally random and disorganized activation of the ventricles. I review theoretical ...
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