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Results 201 - 250 of 1285
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Fichet Jérôme - - 2008
A 21-year-old woman, without medical history, was admitted after cardiac arrest. Cardiopulmonary resuscitation and use of semiautomatic defibrillator quickly restored sinus rhythm. Clinical examination was normal with no cardiac murmur or abnormal heart sound. Electrocardiogram revealed sinus rhythm with short QT interval. Serum electrolytes and arterial blood gazes were normal. ...
Cygankiewicz Iwona - - 2008
INTRODUCTION: Repolarization dynamics, reflecting adaptation of QT to changing heart rate, is considered a marker of unfavorable prognosis in patients with heart diseases. We aimed to evaluate the prognostic value of QT/RR slope in predicting total mortality (TM) and sudden death (SD) in patients with congestive heart failure (CHF). METHODS ...
Zulli Roberto - - 2008
OBJECTIVE: To assess the prevalence and the characteristics of silent myocardial ischaemia (SMI) and ventricular arrhythmias (VA) in subjects with Alzheimer's disease (AD) and mild cognitive impairment (MCI) and their relationships with QT interval dispersion (QTD). METHODS: Thirty-three subjects with AD, 39 subjects with MCI, and 29 cognitive healthy control ...
Furushima Hiroshi - - 2008
A 61-year-old woman had recurrent syncopal attacks caused by torsades de pointes associated with remarkable QT prolongation (QTc = 740 ms). Left ventriculography showed apical akinesis (ballooning) and basal hyperkinesis, but coronary angiography was normal. This was compatible with takotsubo cardiomyopathy. The wall motion of the left ventricle (LV) normalized ...
Volpi S - - 2009
Administration of certain drugs (for example, antiarrhythmics, antihistamines, antibiotics, antipsychotics) may occasionally affect myocardial repolarization and cause prolongation of the QT interval. We performed a whole genome association study of drug-induced QT prolongation after 14 days of treatment in a phase 3 clinical trial evaluating the efficacy, safety and tolerability ...
Maeda Keiko - - 2008
BACKGROUND: Although nifekalant hydrochloride (NIFE) has been demonstrated to suppress ventricular tachyarrhythmia, especially electrical storm, the mechanism by which it does so is still unclear. We examined its effects on the spatial dispersion of repolarization (SDR) after implantable cardioverter-defibrillator (ICD) shock. METHODS AND RESULTS: In twenty five patients with an ...
Brunner Michael - - 2008
Long QT syndrome (LQTS) is a heritable disease associated with ECG QT interval prolongation, ventricular tachycardia, and sudden cardiac death in young patients. Among genotyped individuals, mutations in genes encoding repolarizing K+ channels (LQT1:KCNQ1; LQT2:KCNH2) are present in approximately 90% of affected individuals. Expression of pore mutants of the human ...
Suzuki Shingo - - 2008
The main components of repolarization reserve for the ventricular action potential (AP) are the rapid (I(Kr)) and slow (I(Ks)) delayed outward K(+) currents. While many drugs block I(Kr) and cause life-threatening arrhythmias including torsades de pointes, the frequency of arrhythmias varies between different I(Kr)-blockers. Different types of block of I(Kr) ...
Haïssaguerre Michel - - 2008
BACKGROUND: Early repolarization is a common electrocardiographic finding that is generally considered to be benign. Its potential to cause cardiac arrhythmias has been hypothesized from experimental studies, but it is not known whether there is a clinical association with sudden cardiac arrest. METHODS: We reviewed data from 206 case subjects ...
Schimpf Rainer - - 2008
PURPOSE OF REVIEW: Sudden cardiac death in patients without structural heart disease remains a challenge in diagnostics and risk stratification. Genetically determined arrhythmias are a potential cause for a primary electrical disease. A recently discovered primary electrical disease is discussed. RECENT FINDINGS: The inherited short QT syndrome is a recently ...
Pan Nan-Hung - - 2008
Coronary calcium score is a marker of coronary atherosclerosis and is an important factor of cardiac events. Ventricular hypertrophy and QT dispersion increase the risk of cardiac events. The purpose of the study was to investigate whether coronary calcium score may be related to the changes of QT, QT dispersion, ...
Cruciani Ricardo A - - 2008
There is significant controversy about the potential deleterious effect of methadone on cardiac conduction. Although several reports suggest that patients receiving methadone are at increased risk for QTc prolongation and torsade de pointes, a potentially fatal arrhythmia, others have not replicated these findings. Hence, it is not surprising that there ...
Hamlin Robert L - - 2008
Torsades de pointes is a potentially lethal arrhythmia that occurs infrequently but may be drug-induced particularly in patients with pathological substrates. However drugs are usually evaluated for torsadogenicity in normal subjects, thus potentially limiting the sensitivity of studies to predict liability in man. Heart failure is a pathological substrate permissive ...
Piccirillo Gianfranco - - 2008
Recent evidence shows that pink grapefruit juice, which is a recommended dietary addition that contains high amounts of the antioxidant flavonoid naringenin, prolongs the corrected QT (QT(c)), a noninvasive electrophysiological marker of spatial myocardial repolarization, and does so by inhibiting the rapid component of the delayed rectifier K+ current (I(Kr)). ...
Ellis Christopher R - - 2008
INTRODUCTION: An increasing number of patients with left ventricular (LV) dysfunction are referred for placement of an implantable cardioverter-defibrillator (ICD). CASE REPORT: A 78-year-old female with fatigue, palpitations, and presyncope was referred for consideration of an ICD because of a cardiomyopathy and nonsustained ventricular tachycardia (VT). Her evaluation revealed severe ...
Dimopoulos Stavros - - 2008
Inhomogeneity of ventricular repolarization as detected by QT dispersion may be a potential leading mechanism of sudden death in hypertensive and normotensive (age related) left ventricular hypertrophy. Aim of this study was to investigate QT dispersion, ventricular arrhythmias, and left ventricular mass index in elderly hypertensive and normotensive patients. Study ...
Billman George E - - 2008
AVE0118 is a novel drug that blocks the transient outward current (Ito), the ultra rapid component of the delayed rectifier current (IKur), and the acetylcholine dependent potassium channel (IKach). The latter 2 channels are more abundant in atrial tissue. It is possible that AVE0118 could reduce regional differences in repolarization ...
Yang Zhi-fang - - 2008
AIM: The aim of the present study was to investigate the electrophysiological effect of ibuprofen on the cardiac action potentials (AP) and electrocardiograms (ECG), and to identify its arrhythmiogenic mechanism. METHODS: The intracellular microelectrode recording technique was employed to record the fast- and slowresponse AP in guinea pig papillary muscles. ...
Kolo P M - - 2008
BACKGROUND: The heart rate corrected QT interval (QTc) on the electrocardiogram (ECG) has been proposed as a risk factor for ventricular arrhythmias and death in apparently healthy populations, patients with myocardial infarction and diabetes mellitus. However, data on the significance of QTc prolongation in heart failure are scarce. OBJECTIVE: Our ...
Chang Kuan-Cheng - - 2008
Congenital long- or short-QT syndrome may lead to life-threatening ventricular tachycardia and sudden cardiac death. Apart from the rare disease-causing mutations, common genetic variants in CAPON, a neuronal nitric oxide synthase (NOS1) regulator, have recently been associated with QT interval variations in a human whole-genome association study. CAPON had been ...
Schwoerer Alexander Peter - - 2008
Cardiac unloading with left ventricular assist devices is increasingly used to treat patients with severe heart failure. Unloading has been shown to improve systolic and diastolic function, but its impact on the repolarization of left ventricular myocytes is not known. Unloaded hearts exhibit similar patterns of gene expression as hearts ...
Morita Hiroshi - - 2008
BACKGROUND: Brugada syndrome (BrS) is characterized by repolarization abnormality with ST-segment elevation in the right ventricular outflow tract (RVOT). OBJECTIVE: Although action potential (AP) heterogeneity is associated with induction of ventricular arrhythmias (VA) in BrS, clinical evidence and its experimental correlations are still absent and are the focus of this ...
Schwartz Peter J - - 2008
OBJECTIVES: The purpose of this study was to test the hypothesis that differences in autonomic responses might modify clinical severity in long QT syndrome type 1 (LQT1) patients, those with KCNQ1 mutations and reduced I(Ks), in whom the main arrhythmia trigger is sympathetic activation. BACKGROUND: Some long QT syndrome (LQTS) ...
Wung Shu-Fen - - 2008
The electrocardiogram (ECG) is indispensable for the diagnosis and management of patients with a wide variety of cardiac and noncardiac diseases. The purpose of this paper is focused on recent research that used ECG, specifically the long-QT interval and microvolt T wave alternans, for the evaluation of life-threatening ventricular arrhythmias. ...
Nakai Kenji - - 2008
The purpose of this study was to verify the spatial distribution of myocardial repolarization heterogeneity using a newly developed 187-channel signal-averaged vector-projected ECG (187-ch SAVP-ECG). We constructed corrected recovery time (RTc) and Tpeak-end (corrected Tp-e) dispersion maps using a 187-ch SAVP-ECG based on vector-projection theory using a Mason-Likar lead system. ...
Jiang Hong - - 2008
OBJECTIVE: The roles of electrical restitution determined by epicardial contact mapping and surface electrocardiogram (ECG) in the inducibility of ventricular fibrillation (VF) were evaluated. METHODS: Ten epicardial unipolar electrograms using contact mapping and the surface ECGs were simultaneously recorded in 7 swine. Activation-recovery interval (ARI) and QT-interval restitution curves were ...
Di Micoli A - - 2009
We describe an interesting case of a woman with decompensated cirrhosis, ischaemic heart disease and prolonged QT interval, who developed a new-onset atrial fibrillation. During amiodarone infusion a torsade de pointes occurred, which was immediately converted to sinus rhythm by synchronized cardioversion. A new episode of atrial fibrillation was treated ...
Azarov J E - - 2008
AIM: Prolongation of ventricular repolarization is characteristic of myocardial cooling. In the present study, we investigated whether this prolongation is uniform or not throughout ventricular epicardium and how these hypothermia-induced changes express in the body surface potential distribution. METHODS: Epicardial and body surface potential mapping from 64 unipolar leads was ...
Taggart Peter - - 2008
Electrical restitution in the heart is the property whereby the action potential duration and conduction velocity of a beat of altered cycle length vary according to its immediacy to the preceding basic beat--the coupling interval, usually the diastolic interval. In general, action potential duration (APD) increases with increasing coupling interval, ...
Tuncer Mustafa - - 2008
BACKGROUND: There have been reports demonstrating an association between increased QT dispersion and ventricular arrhythmia in a variety of pathological cardiac conditions, including left ventricular hypertrophy. However, there are limited data about an association of right ventricular hypertrophy (RVH) and corrected QT (QTc) dispersion. MATERIAL/METHODS: Eighty-five persons who emigrated from ...
Rivard Katy - - 2008
AIMS: Mice with cardiac-specific overexpression of human angiotensin II type 1 receptor (AT1R) undergo cardiac remodelling and die prematurely of sudden death. Since excessive QT prolongation is a major risk factor for ventricular arrhythmias and sudden death, we hypothesize that chronic stimulation of AT1R might contribute to sudden death by ...
Patel Chinmay C Masonic Medical Research Laboratory, Utica, New York 13501, - - 2008
Short QT syndrome (SQTS) is a primary electrical disease of the heart associated with a high risk of sudden cardiac death. A gain-of-function in I(Kr), due to a mutation in KCNH2, underlies SQT1. This study sought to examine the cellular basis for arrhythmogenesis in an experimental model of SQT1 created ...
Savelieva Irina - - 2008
Ivabradine belongs to a new class of specific heart rate reducing agents that inhibit spontaneous pacemaker activity of the sinus node by selectively and specifically inhibiting the I(f) current; thus, allowing heart rate reduction without affecting myocardial contractility, relaxation and peripheral vascular resistance. In clinical studies involving >3500 patients and ...
Hansen Stig - - 2008
BACKGROUND: QT dispersion is considered an index of spatial inhomogeneity of repolarization duration and increased dispersion of ventricular repolarization is supposed to increase the risk of ventricular arrhythmia. Circadian variation in QT dispersion was investigated. METHODS: Three different modes of lead selection was used: all 12-leads (QTdisp 12), only precordial ...
Hutton Darlene M - - 2008
When monitoring a patient's cardiac rhythm, the QT interval should be routinely measured. A variety of factors can prolong the QT interval such as drug effects, electrolyte imbalances, acute myocardial infarction, and congenital factors. The biggest risk with prolongation of the QT interval is the development of Torsades de Pointes. ...
Alper Ahmet Taha - - 2008
Exposure to toluene, one of the major components of glue, can lead to cardiac arrhythmias and sudden sniffing death syndrome. QT dispersion is a useful risk marker for cardiac arrhythmias and sudden cardiac death. The aim of this study was to investigate the effects of glue abuse on QT interval ...
Szydlo Krzysztof - - 2008
BACKGROUND: The relation between postinfarction left ventricle remodeling (LVR), autonomic nervous system and repolarization process is unclear. Purpose of the study was to assess the influence of LVR on the early (QTpeak) and late (TpeakTend) repolarization periods in patients after myocardial infarction (MI) treated with primary PCI. The day-to-night differences ...
Zambruni Andrea - - 2008
BACKGROUND/AIMS: QT interval prolongation is frequent in cirrhosis, predicts a poor prognosis and may trigger severe ventricular arrhythmias. Our aim was to evaluate the effect of chronic beta-blockade on QT prolongation. METHODS: Clinical and laboratory evaluation, ECG and hepatic vein pressure gradient (HVPG) measurement were performed in 30 cirrhotic patients ...
Narayan Sanjiv M - - 2007
OBJECTIVES: Our aim was to study the relationship between T-wave alternans (TWA) and rate-response (restitution) of repolarization in subjects with and without ventricular systolic dysfunction. BACKGROUND: T-wave alternans is a promising predictor of sudden death, yet the mechanisms linking it with human ventricular arrhythmias are unclear. From theoretic considerations, we ...
Vizzardi Enrico - - 2008
Arsenic trioxide is an effective treatment for patients with acute promyelocytic leukaemia (APL) who have relapsed from or are refractory to all trans-retinoic acid and anthracycline chemotherapy. Cardiac effects observed include electrocardiographic changes such as QTc prolongation, T-wave abnormalities, torsades de pointes and sudden death. We describe a case of ...
Moriya Manabu - - 2007
BACKGROUND: The epidemiology of short QT interval remains unclear. We attempted to determine the incidence and clinical characteristics of short QT interval in a longitudinal cohort study. METHODS: A total of 19,153 subjects (7,525 male, 11,628 female) were enrolled in the study and all available electrocardiograms (ECGs) were investigated longitudinally ...
Tran Diana X - - 2007
Ventricular fibrillation is a lethal arrhythmia characterized by multiple wavelets usually starting from a single or figure-of-eight re-entrant circuit. Understanding the factors regulating vulnerability to the re-entry is essential for developing effective therapeutic strategies to prevent ventricular fibrillation. In this study, we investigated how pre-existing tissue heterogeneities and electrical restitution ...
Killeen M J - - 2008
Sudden cardiac death stemming from ventricular arrhythmogenesis is one of the major causes of mortality in the developed world. Congenital and acquired forms of long QT syndrome (LQTS) are in turn associated with life threatening arrhythmias. Over the past decade our understanding of arrhythmogenic mechanisms in the setting of these ...
Stoll Marion - - 2008
AIMS: In the heart, there is not only a transmural gradient of left ventricular perfusion and action potential duration (APD), but also spatial heterogeneity within each myocardial layer, where local blood flow and energy turnover vary more than three-fold between individual regions. We analysed at high spatial resolution whether a ...
Alvarado Serrano, Carlos
Increased dispersion of QT interval in the 12-lead ECG have been proposed as risk factor of ventricular arrhythmias in post myocardial infarction (post-MI) patients, but its sensitivity and specifity is low for diagnosis and/or prognosis. We evaluate dispersion in other ventricular activity intervals, in order to determine whether they improve ...
Flaim Sarah N - - 2007
Unlike other variants of long QT syndrome, LQT3 patients are particularly susceptible to cardiac events during sleep. Changes in heart rate alone fail to fully account for this phenomenon. We hypothesize that the parasympathetic nervous system may play a role in increasing arrhythmic risk in the mammalian ventricular myocardium via ...
Starobin Joseph M - - 2007
Because myocardial ischemia induces QT/RR hysteresis, a correlation was hypothesized to exist between the extent of myocardial flow reduction and the magnitude of QT/RR hysteresis. Graded reductions in regional myocardial perfusion in the distribution of the left anterior descending coronary artery in open-chest pigs were used to model 1-vessel coronary ...
Namba Tsunetoyo - - 2007
PURPOSE: The aim of this study was to investigate whether bipolar electrode potentials (BEPs) reflect local myocardial repolarization dynamics, using computer simulation. METHODS: Simulated action potential and BEP mapping of myocardial tissue during fibrillation was performed. The BEP was modified to make all the fluctuations have the same polarity. Then, ...
Ghanem Raja N RN Medtronic Cardiac Rhythm Disease Management, Minneapolis, MN, USA. - - 2007
Sudden cardiac death remains the leading cause of death, claiming more than 1000 lives per day in the United States alone. Noninvasive means to diagnose rhythm disorders of the heart have relied heavily on the 12-lead electrocardiogram and, to a lesser extent, on higher-resolution body-surface mapping. These lack sensitivity and ...
Gallagher Mark M - - 2007
AIMS: To test the hypothesis that the QS interval of ventricular ectopic beats (VEBs) (ventricular ectopic QS interval, VEQSI) would provide a marker for the presence of structural heart disease and a predictor of mortality. METHODS AND RESULTS: We interviewed and examined 2332 patients undergoing Holter ECG monitoring for clinical ...
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