Search Results
Results 301 - 350 of 1283
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Tysler M - - 2007
A method using body surface potential maps for assessment of myocardium lesions with changed repolarization is presented and suitable mapping system is introduced. Differences between normal and altered QRST integral maps together with torso volume conductor model were used to determine the equivalent dipole representing the lesion. Performance of the ...
Makaryus Amgad N - - 2007
BACKGROUND: Prior studies have shown the utility of using both QRS duration and QT dispersion (QTd) as predictors of risk for ventricular tachyarrhythmias (VA). Lengthening of the QRS duration represents dyssynchrony of regional myocardial wall contraction, and increased QTd similarly represents variations in myocardial repolarization. We sought to examine the ...
Remme Carol Ann - - 2006
Patients carrying the cardiac sodium channel (SCN5A) mutation 1795insD show sudden nocturnal death and signs of multiple arrhythmia syndromes including bradycardia, conduction delay, QT prolongation, and right precordial ST-elevation. We investigated the electrophysiological characteristics of a transgenic model of the murine equivalent mutation 1798insD. On 24-hour continuous telemetry and surface ...
Suto Fumiaki - - 2007
Bradycardic ventricular electrical remodeling predisposes to lethal tachyarrhythmias. We investigated the early temporal sequence and reversibility of electrical remodeling in a rabbit complete heart block model subjected to bradycardic ventricular pacing for either 2 or 8 days, with a third group of animals undergoing 8 days of bradycardic pacing followed ...
Yíldírím Nesligül - - 2006
OBJECTIVE: Electrocardiographic indices like maximum P-wave duration (P(max)) and P-wave dispersion (PD) can be used to detect patients with atrial conduction disorders, myocardial ischemia and those at risk for atrial fibrillation. Considering the diurnal variation of ischemia in patients with significant coronary lesions, this study was designed to investigate the ...
Koturoglu G - - 2006
QT prolongation is rarely seen after acute stress reactions such as burn injury and severe head trauma. Although pathophysiologic mechanism is not entirely clear, acute stress is thought to contribute to the inhomogeneity of ventricular repolarization and it is hypothesized that QTc dispersion increases with severity of acute stress conditions. ...
Aytemir Kudret - - 2007
BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is characterized by the repeated episodes of upper airway obstruction during sleep, leading to significant hypoxia. Noninvasive evaluation of autonomic nervous system (ANS) and myocardial vulnerability may help determination of OSAS patients who are under high risk of malignant cardiac arrhythmias. The aim of ...
Opthof Tobias - - 2007
BACKGROUND: The concept that the interval between the peak (T(peak)) and the end (T(end)) of the T wave (T(p-e)) is a measure of transmural dispersion of repolarization time is widely accepted but has not been tested rigorously by transmural mapping of the intact heart. OBJECTIVES: The purpose of this study ...
Järvenpää Jere - - 2007
Prolonged and labile ventricular repolarization and decreased heart rate variability may be associated with susceptibility to ventricular fibrillation (VF) after myocardial infarction (MI). The response of ventricular repolarization related to abrupt heart rate changes may also be associated with arrhythmia vulnerability. We investigated whether diurnal maximal values or changing capacities ...
Piccirillo Gianfranco - - 2007
AIMS: The most widely accepted marker for stratifying the risk of sudden cardiac death (SCD) in post myocardial infarction patients is a depressed left ventricular function. Left ventricular ejection fractions (EF) of 35% or less increase the risk of sudden death but values between 35 and 40% raise concern. The ...
Bonnemeier Hendrik - - 2006
OBJECTIVE: Even though diffuse T wave inversion and prolongation of the QT interval in the surface electrocardiogram (ECG) have been consistently reported in patients with transient stress-induced left ventricular apical ballooning (AB), ventricular repolarization has not yet been systematically investigated in this clinical entity. BACKGROUND: AB, an emerging syndrome that ...
Azarov Jan E - - 2007
Our study compared the contributions of activation sequence and local repolarization durations distribution in the organization of epicardial repolarization in animals with fast (rabbit) and slow (frog) myocardial activation under sinus rhythm. Activation times, repolarization times and activation-recovery intervals (ARI) were obtained from ventricular epicardial unipolar electrograms recorded in 13 ...
Cuesta-Frau David - - 2007
Ventricular extrasystoles (VE) are ectopic heartbeats involving irregularities in the heart rhythm. VEs arise in response to impulses generated in some part of the heart different from the sinoatrial node. These are caused by the premature discharge of a ventricular ectopic focus. VEs after myocardial infarction are associated with increased ...
Thomas Glyn G Section of Cardiovascular Biology, Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, - - 2007
Mutations within KCNE1 encoding a transmembrane protein which coassembles with K+ channels mediating slow K+, I(Ks), currents are implicated in cardiac action potential prolongation and ventricular arrhythmogenicity in long QT syndrome 5. We demonstrate the following potentially arrhythmogenic features in simultaneously recorded, left ventricular, endocardial and epicardial monophasic action potentials ...
Boineau John P - - 2007
A detailed description of the electrocardiogram of the early repolarization variant, including its most common morphological variations is presented. Included is a recently identified anomaly of the QRS complex, which has not previously been reported. Ventricular activation data is presented to explain the unique QRS changes. A comparison with Wolff-Parkinson-White ...
Lerma Claudia - - 2007
BACKGROUND: The rule of bigeminy is commonly explained by a reentrant mechanism. We hypothesize that in patients with prolonged ventricular repolarization, the rule of bigeminy may be caused by premature ventricular complexes (PVCs) due to early afterdepolarizations. We evaluated these ventricular arrhythmias over extended periods in patients with sudden cardiac ...
Haapalahti Petri - - 2006
BACKGROUND: In the most prevalent LQT1 form of inherited long QT syndrome symptoms often occur during abrupt physical or emotional stress. Sympathetic stimulation aggravates repolarization abnormalities in experimental LQT1 models. We hypothesized that autonomic function tests might reveal the abnormal repolarization in asymptomatic LQT1 patients. METHODS: We measured heart rates ...
King Andrew - - 2006
BACKGROUND: Accurate detection of drug-induced QT interval changes is often confounded by concurrent heart rate changes. Application of heart rate correction formulas has been the traditional approach to account for heart rate-induced QT interval changes, and thereby identify the direct effect of the test article on cardiac repolarization. Despite numerous ...
Yamazaki Masatoshi - - 2006
A 21-year-old male experienced frequent episodes of polymorphic ventricular tachycardia (PVT) initiated by a closely coupled premature ventricular complex (PVC) in the absence of QT prolongation and structural heart disease. Programmed stimulation at right ventricular apex (RVA), but not at the outflow tract (RVOT), provoked PVT degenerating into ventricular fibrillation ...
Hiromoto Kenji - - 2006
BACKGROUND: Beat-to-beat QT interval variability (QTV) is associated with sudden cardiac death and New York Heat Association functional class severity. We sought to evaluate the relationship between QTV and left ventricular (LV) function in patients with previous myocardial infarction (MI). METHODS: Fifty-nine patients with previous anterior MI were enrolled. LV ...
Guzik Przemyslaw - - 2006
The Poincaré plot is a widely used method for visualizing and calculating heart rate variability and for investigating the oscillatory nature of heart action. We show that the Poincaré plot produced using physiological data for RR intervals is asymmetric. This suggests that the processes of heart rate acceleration (shortening of ...
Oren Hüseyin - - 2007
BACKGROUND: A circadian and seasonal variation of QT dispersion (QTd) has been shown in healthy individuals. Nevertheless, no data exist regarding the weekly influences on the QTd in healthy individuals and in patients with coronary heart disease (CHD). Design: This study was designed to determine whether there is a weekly ...
Lu Hua Rong - - 2006
The prolongation of the ventricular repolarization and proarrhythmic effects (Torsade de Pointes: TdP) of five reference antibiotics were compared in four in-vitro models. 1. Using the patch clamp technique on the human ether-a-gogo-related gene (HERG) current, the rank order for blockade of the HERG-current (IC(50)) was: sparfloxacin (44 microM)>telithromycin=moxifloxacin=erythromycin (+/-100 ...
Chinushi Masaomi - - 2006
This study was performed to examine the role played by the autonomic nervous system in the antiarrhythmic effects of magnesium sulfate (Mg) in a canine model of polymorphic ventricular tachyarrhythmia facilitated by anthopleurin-A and a slower heart rate induced QT interval prolongation. In 6 experiments, complete atrioventricular block was created ...
Yoshioka Koichiro - - 2006
BACKGROUND: Because nifekalant hydrochloride (NIF) displayed a superior defibrillating effect on ventricular tachycardia/fibrillation (VT/VF) in cardiopulmonary arrest (CPA) patients, despite some QT prolongation, its effect on transmural dispersion of repolarization (TDR) in the left ventricle (LV) in an animal model of CPA was investigated. METHODS AND RESULTS: Eight beagle dogs ...
Bar-Cohen Yaniv - - 2006
The long QT syndrome (LQTS) is characterized by electrocardiographic abnormalities and a high incidence of syncope and sudden cardiac death (SCD). The diagnosis is suggested when ventricular repolarization abnormalities result in prolongation of the corrected QT interval. When LQTS is suspected, genetic screening may identify a specific long QT subtype ...
Lu Li Xiong - - 2006
The short QT syndrome has been recently recognised as a genetic ion channel dysfunction. This new clinical entity is associated with an incidence of sudden cardiac death, syncope, and atrial fibrillation in otherwise healthy individuals. The distinctive ECG pattern consists of an abnormally short QT interval, a short or even ...
Baker K E - - 2006
PAF antagonists inhibit ischaemia-induced ventricular fibrillation (VF) in animals. However, unfavourable ancillary actions (on QT interval and coronary flow) have been reported with the PAF antagonist, BN-50739. If these are class actions, they would preclude development of PAF antagonists as novel anti-VF drugs. Our purpose was to examine this proposition ...
Cagli Kerim - - 2006
The electrocardiographic changes early after uncomplicated coronary artery bypass with complete revascularization were examined preoperatively and on the 1st and 3rd postoperative days in 53 patients. Heart rate, PR index, corrected PR interval, corrected P dispersion, corrected duration of QRS complex, corrected QT dispersion, corrected QT interval, rhythm, QRS axis, ...
Medei Emiliano - - 2007
INTRODUCTION: In chronic chagasic patients sudden death has been reported when QT interval dispersion is increased and antibodies with muscarinic-like activity have been demonstrated to trigger arrhythmias. The aims were to investigate, in vivo and in vitro, relation between these antibodies and heterogeneity of ventricular repolarization and to identify predictors ...
Viitasalo Matti - - 2006
OBJECTIVES: We tested the hypothesis that in long-QT syndrome (LQT) type 1 (LQT1), beta-blocker therapy may decrease both the diurnal maximal T-wave peak to T-wave end interval (TPE) and the maximal ratio between late and early T-wave peak amplitude (T2/T1 ratio), which are electrocardiographic counterparts of transmural dispersion of repolarization ...
Smith Fiona E - - 2006
AIMS: There is some dispute over the clinical significance of dispersion of ventricular repolarization measurements from the electrocardiogram. Recent studies have indicated that multichannel magnetocardiograms (MCGs), which non-invasively measure cardiac magnetic field strength from many sites above the body surface, may provide independent information from ECGs about ventricular repolarization dispersion. ...
Pratt Craig M - - 2006
OBJECTIVES: The purpose of this study was to assess the incidence, temporal characteristics, and risk factors associated with azimilide-associated torsades de pointes (TdP) ventricular tachycardia. BACKGROUND: Azimilide dihydrochloride is a class III antiarrhythmic drug possessing Ikr and Iks channel-blocking properties. METHODS: Oral azimilide (75 to 125 mg/day) was taken by ...
Varriale Philip - - 2006
OBJECTIVE: To describe the clinical experience of patients with polymorphic ventricular tachycardia (PMVT) in a hospital setting. METHODS: A 2-year prospective, observational study of patients with symptomatic and asymptomatic PMVT admitted to the coronary care unit of a community medical center. Electrocardiograms were reviewed for a pattern diagnostic of PMVT, ...
Severi Stefano - - 2006
A therapy-specific worsening of cardiovascular stability during bicarbonate dialysis (BD) with respect to acetate-free biofiltration (AFB) have been previously reported. We further investigated the impact of the 2 therapies on electrocardiographic parameters in order to gain novel insight into the cardiac responses. Holter ECG acquired during hypotension-free sessions (12 BD ...
Mechleb Bassam K - - 2006
Polymorphic ventricular tachycardia (PVT) is a life-threatening arrhythmia that is typically related to long QT syndrome, organic heart disease, electrolyte abnormalities, cardiotoxic drugs, or adrenergic stimulation. A review of the literature reveals that PVT with normal QT interval and without underlying cause is quite rare. We report a case of ...
Zhang Y-Z - - 2007
The effect of increased coronary flow on transmural ventricular repolarization was investigated in six pentobabital-anesthetized sheep. Fresh blood at 10 ml/min was injected into the left circumflex coronary artery (LCX) in addition to the normal coronary flow. Unipolar electrocardiograms were simultaneously registered from epicardium, mid-myocardium and endocardium with fine plunge ...
Zhao Hui - - 2006
Abnormal cardiac repolarization renders the heart susceptible to lethal ventricular tachyarrhythmias, increasing the risk of sudden cardiac death in all ages; however, little is known about the incidence and etiology of T-wave abnormalities in utero. In this study, magnetocardiography was used to better define fetal T-wave characteristics, including the QT ...
Piekarz Richard L - - 2006
PURPOSE: The histone deacetylase inhibitor depsipeptide (FK228) has activity in patients with cutaneous or peripheral T-cell lymphoma. Electrocardiogram abnormalities, thought to be a class effect, were observed in preclinical animal studies and phase I testing and led to the incorporation of intensive cardiac monitoring in an ongoing efficacy trial. Patients ...
Draisma Harmen H M - - 2006
The ventricular gradient, a notion conceived by Wilson et al during the 1930s, has contributed considerably to a better understanding of the ECG manifestations of the cardiac repolarization process. The power of the ventricular gradient is its ability to assess the primary factors that contribute to the T wave (i.e., ...
Hooft van Huysduynen, Bart
Repolarization heterogeneity refers to differences in repolarization instants in the heart. Normally, repolarization in the human heart is a relatively smooth, continuous process, during which adjacent areas repolarize almost simultaneously. Several drugs or cardiac diseases may disturb the repolarization and thus increase the repolarization heterogeneity, which predisposes to arrhythmias. A ...
Santangelo Lucio - - 2006
AIMS: The aim of our study was to evaluate the effect of cardiac resyncronization therapy on QT dispersion (QTd), JT dispersion (JTd), and transmural dispersion of repolarization (TDR), markers of heterogeneity of ventricular repolarization in a study population with severe heart failure. METHODS AND RESULTS: Fifty patients (43 male, 7 ...
Larroude Charlotte E - - 2006
BACKGROUND: QT dynamics parameters are used only in sinus rhythm. However, because many patients with paroxysmal atrial fibrillation undergo antiarrhythmic treatment that changes QT, developing methods for measuring QT dynamics during atrial fibrillation is important. OBJECTIVES: The purpose of this study was to evaluate whether QT dynamics in atrial fibrillation ...
Alvarado-Serrano Carlos - - 2006
We propose novel indices of ventricular repolarization intervals, the JTp/JT, Tpe/JTp and Tpe/JT ratios. These indices have been compared with the duration of the ventricular repolarization intervals and other ratios in 17 normal subjects and 17 patients with old myocardial infarction. In the intervals and other ratios, the best separation ...
Karp Jeffrey M - - 2006
BACKGROUND: Long QT syndrome (LQTS) is associated with life-threatening cardiac arrhythmias causing syncope and sudden cardiac death, frequently precipitated by physical or psychological stress. TYPES OF STUDIES REVIEWED: The authors did a literature review of data published in peer-reviewed medical and dental journals. They also extracted epidemiologic information, correlations between ...
Okmen Ertan - - 2006
Coronary ischemia augments inhomogeneity in ventricular repolarization. Decrease in the QT dispersion (QTd) following restoration of coronary blood flow to the ischemic myocardium by successful percutaneous coronary intervention (PCI) is an expected outcome. The purpose of the study was to seek whether glycoprotein IIb/IIIa (GP IIb/IIIa) inhibition has additional beneficial ...
Furukawa Yoshio - - 2006
BACKGROUND: Recent studies have demonstrated that increased QT interval variability (QTV) is associated with a greater susceptibility to ventricular arrhythmias and that patients with prior myocardial infarction (MI) were prone to ventricular arrhythmias during the daytime. The goal of the present study was to investigate the circadian variation of the ...
Schillaci Giuseppe - - 2006
BACKGROUND: QT interval prolongation on the surface electrocardiogram (ECG) predicts cardiovascular complications in high-risk subjects, but its prognostic role in uncomplicated hypertension has been understudied. METHODS: For up to 13 years (average, 5.3 years), we followed up 2110 white patients with initially untreated essential hypertension (mean +/- SD age, 49 ...
Isbister Geoffrey K - - 2006
Although clinical trials of the antipsychotic amisulpride revealed no cardiac adverse effects, four patients with severe cardiac toxicity after overdose were reported to Australian poisons information centres in 2004-2005. All four had QT prolongation over 500 ms, two had rate-dependent bundle branch block, two developed torsades de pointes, and one ...
Boineau John P - - 2006
Although the ventricular muscle band (VMB) is formed by one continuous band of myocardium and there is some evidence to suggest that it may contract sequentially along its course from the right ventricle, through the septum, then along its basoapical left ventricular spiral, the structure is not activated in this ...
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