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Lee Kun-Tai - - 2009
Cardiac memory (CM) can alter the configuration of action potentials and the transmural repolarization gradient in ventricular tissue. This study evaluated the effects of CM on ventricular arrhythmogenicity. A total of 20 patients (12 females, 8 males; mean age, 46 +/- 13 years) were enrolled. The following indicators were measured ...
Do─čru Mehmet Tolga - - 2009
OBJECTIVE: We aimed to investigate the effects of autonomic and left ventricular functional and structural changes on QT interval and dispersion differences between normal and prehypertensive patients. METHODS: A total of 291 normotensive patients (<140/90 mmHg) (135 males, age range: 16-75 years, mean age: 45+/- 11 years; 156 females, age ...
Pueyo Esther - - 2009
Sudden cardiac death (SCD) is a challenging health problem in the western world. Analysis of cardiac repolarization from the electrocardiogram (ECG) provides valuable information for stratifying patients according to their risk of suffering from arrhythmic events that could end in SCD, as well as for assessing efficacy of antiarrhythmic therapies. ...
Dautova Yana - - 2009
Long QT(3) (LQT3) syndrome is associated with abnormal repolarisation kinetics, prolonged action potential durations (APD) and QT intervals and may lead to life-threatening ventricular arrhythmias. However, there have been few physiological studies of its effects on atrial electrophysiology. Programmed electrical stimulation and burst pacing induced atrial arrhythmic episodes in 16 ...
Coronel Ruben - - 2009
BACKGROUND: The relation between induction of arrhythmias and dispersion of repolarization is not completely understood. OBJECTIVE: The purpose of this study was to study the relation between heterogeneity in repolarization and arrhythmogenesis under conditions of selective regional action potential prolongation and shortening. METHODS: Pig hearts were perfused in a Langendorff ...
Paulin Frédéric L - - 2009
INTRODUCTION: Pheochromocytoma may present with ECG abnormalities as one of the few clues to the diagnosis. METHODS AND RESULTS: A 30-year-old woman presented with chest pain and a QTc of 525 ms. Four weeks later following a syncopal episode, her QTc was 660 ms. Short runs of monomorphic ventricular tachycardia ...
Zhu Tian Gang - - 2009
AIMS: We investigated the role of ventricular repolarization sequence in ventricular diastolic function. METHODS AND RESULTS: Arterially perfused canine left ventricular wedge preparation with simultaneous recording of action potentials and isometric contractile force was used to establish the relationship between ventricular repolarization and relaxation sequences. An isolated rabbit working heart ...
Wiegerinck Rob F - - 2009
AIM: To investigate ventricular conduction and refractoriness before and after application of rotigaptide, an enhancer of gap junctional conductance, to explanted hearts of patients with heart failure (HF). METHODS AND RESULTS: In six explanted perfused hearts of patients with end-stage HF, activation/repolarization mapping was performed and refractory periods (RPs) and ...
Soliman Elsayed Z - - 2009
BACKGROUND: The dynamic nature of QT dispersion (QTd) and the absence of an acceptable normal value suggest that the relative change not the absolute value of QTd would be a better predicator of coronary restenosis. We sought to examine the usefulness of the relative change in QTd, compared to the ...
Cuddy Thomas Edward - - 2009
As many as half of all sudden cardiac deaths are unexpected, with no preceding symptoms or signs of cardiac problems. Since 1948, the Manitoba Follow-up Study has prospectively recorded routine medical information and resting electrocardiographic (ECG) findings from a cohort of 3983 men. During 58 years of follow-up, 180 men ...
Extramiana Fabrice - - 2009
Ventricular repolarization properties are dependent on cardiac cycle length. The aim of this article is to emphasize the importance of taking into account heart rate influences on QT duration but also on current and future T-wave morphology parameters. The relationship between QT interval duration and RR interval is a fundamental ...
Murat Sani N - - 2009
OBJECTIVES: Ivabradine is the first specific heart rate-lowering agent that has completed clinical development for stable angina pectoris. The aim of the present study was to investigate the effects of ivabradine therapy on P-wave duration, dispersion and QT duration, dispersion in coronary artery disease patients. METHODS AND RESULTS: The study ...
Quan Xiao-Qing - - 2009
Gap junctions contribute to the transmural heterogeneity of repolarization in the normal heart and under conditions of prolonged QT interval in the diseased heart. This study examined whether enhancing of gap junction coupling can reduce transmural dispersion of repolarization (TDR) and prevent torsade de pointes (TdP) in a canine LQT2 ...
Uchiyama Katsuharu - - 2009
BACKGROUND: Although QT variables such as its interval and/or dispersion can be clinical markers of ventricular tachyarrhythmia, few data exist regarding the role of QT variables in genotyped hypertrophic cardiomyopathy (HCM). Therefore, we analyzed QT variables in genotyped subjects with or without left ventricular hypertrophy (LVH). METHODS: QT variables were ...
Nemec Jan - - 2009
BACKGROUND: Increased QT variability (QTV) has been reported in conditions associated with ventricular arrhythmias. Data on QTV in patients with congenital long QT syndrome (LQTS) are limited. METHODS: Ambulatory electrocardiogram recordings were analyzed in 23 genotyped LQTS patients and in 16 healthy subjects (C). Short-term QTV was compared between C ...
Gjesdal Knut - - 2008
This editorial discusses arrhythmogenic right ventricular cardiomyopathy (ARVC) with respect to diagnosis and organisation of patient care. Two papers in the current issue are commented upon. Aneq and coworkers present a long-term echocardiographic study on ARVC patients. Baseline changes were seldom diagnostic, but over years, changes in right ventricular structure ...
Bär Karl-Jürgen - - 2008
Previous studies have shown that untreated patients with acute schizophrenia present with reduced heart rate variability and complexity as well as increased QT variability. This autonomic dysregulation might contribute to increased cardiac morbidity and mortality in these patients. However, the additional effects of newer antipsychotics on autonomic dysfunction have not ...
Haapalahti Petri - - 2008
OBJECTIVES: Patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) experience exercise-related malignant arrhythmias possibly based on delayed repolarization in the diseased right ventricle (RV). Autonomic interventions might unveil repolarization abnormalities in RV. DESIGN: We recorded 25-lead electrocardiograms from nine symptomatic ARVC patients and nine controls during rest, Valsalva maneuver, mental stress, ...
Letsas Konstantinos P - - 2009
The present study aimed to investigate the causative medications and underlying risk factors that predispose to drug-induced QT interval prolongation. Twenty-one patients with drug-induced long QT (90% females, mean age 64.3 +/- 14.1 years) were included in the study. Transthoracic echocardiography as well as continuous or ambulatory 48-h electrocardiographic monitoring ...
Maury Philippe - - 2008
The short QT syndrome, a recently discovered ion channel disorder, combines shortened repolarization, a predisposition to atrial and ventricular fibrillatory arrhythmias, and a risk of sudden death. Few cases have been reported, but the prevalence may be underestimated. This syndrome might account for some cases of unexplained ventricular fibrillation in ...
Kors Jan A - - 2008
BACKGROUND: The interval between T peak (Tp) and T end (Te) has been proposed as a measure of transmural dispersion of repolarization, but experimental and clinical studies to validate Tp-Te have given conflicting results. We have investigated the meaning of Tp-Te and its diagnostic potential. METHODS: We used a digital ...
Zareba Wojciech - - 2008
The long QT syndrome (LQTS) is a genetic disorder characterized by prolongation of the QT interval in the electrocardiogram (ECG) and a propensity to torsades de pointes ventricular tachycardia frequently leading to syncope, cardiac arrest, or sudden death usually in young otherwise healthy individuals. The long QT syndrome is caused ...
Shehab A - - 2008
BACKGROUND AND OBJECTIVE: The blocking of aldosterone or angiotensin II receptors improves mortality in patients with chronic heart failure. We explored whether combining losartan and spironolactone would have any added benefit on the known surrogate of mortality by using heart rate variability (HRV) and QT dispersion as our endpoints. METHODS: ...
Maule Simona - - 2008
A prolonged QT interval is a risk factor for ischemic heart disease in hypertensive subjects. Heart rate variability (HRV) is both an index of autonomic function and an important prognostic factor in several diseases. The aim of the present study was to evaluate the relation between a prolonged QT interval ...
George Sanju - - 2008
Evidence has emerged in recent years on methadone's cardiac arrhythogenic potential - i.e. QT prolongation and Torsades de Pointes (TdP). Given the potentially fatal consequences of these adverse effects, clinicians need to be alert to avoid this going unrecognised and untreated. In this paper, we briefly discuss normal cardiac conduction ...
Atallah Joseph - - 2008
BACKGROUND: Left cardiac sympathetic denervation is one of the therapeutic modalities used in the management of patients with medically refractory long QT syndrome. Traditionally, a thoracotomy or cervical incision has been used as the standard surgical approach for performing left cardiac sympathetic denervation. Video-assisted thoracoscopic surgery allows a minimally invasive ...
Peters Stefan - - 2008
The case of a 26-year-old male with sudden cardiac arrest due to ventricular fibrillation and the final diagnosis of arrhythmogenic right ventricular dysplasia-cardiomyopathy (ARVD/C) and initial early repolarization phenomenon is presented in detail. An additional analysis of early repolarization in additional 359 patients with ISFC/ESC diagnostic criteria of ARVD/C revealed ...
Haugaa Kristina Hermann - - 2009
The aim of this study was to investigate whether prolonged and dispersed myocardial contraction duration assessed by tissue Doppler imaging (TDI) may serve as risk markers for cardiac events (documented arrhythmia, syncope, and cardiac arrest) in patients with long QT syndrome (LQTS). Seventy-three patients with genetically confirmed LQTS (nine double- ...
Myerburg Robert J - - 2008
The association between early repolarization patterns on electrocardiograms and risk of idiopathic ventricular fibrillation reported by Haïssaguerre et al. raises questions about the generally held concept that early repolarization is a benign electrocardiographic pattern. Although the association reported is strong enough to suggest validity, the data do not permit distinction ...
Hothi Sandeep S - - 2008
The gain-of-function Scn5a+/DeltaKPQ mutation in the cardiac Na(+) channel causes human long QT type 3 syndrome (LQT3) associated with ventricular arrhythmogenesis. The K(ATP) channel-opener nicorandil (20muM) significantly reduced arrhythmic incidence in Langendorff-perfused Scn5a+/Delta hearts during programmed electrical stimulation; wild-types (WTs) showed a total absence of arrhythmogenicity. These observations precisely correlated ...
Killeen Matthew J - - 2008
Sudden cardiac death resulting from ventricular arrhythmogenesis is a leading cause of mortality in the developed world, accounting for up to 400,000 deaths per year in the US alone. Within the past forty years we have taken considerable leaps forward in our understanding of the causes and mechanisms underlying cardiac ...
Crystal Matthew A - - 2008
Kawasaki disease (KD), while primarily an acute, self-limited, multisystem vasculitis, is more appropriately described as a pancarditis, from a cardiac perspective. Many patients are noted to have ventricular dilation on initial echocardiography; however, functional and structural measurements may remain within the normal range. The authors sought to determine echocardiographic and ...
Barajas-Martinez Hector - - 2009
AIMS: Women have a higher incidence of long QT-related arrhythmias, whereas men exhibit a higher incidence of Brugada syndrome (BrS). The cardiac sodium current (I(Na)) is associated with arrhythmias in BrS and long QT-syndrome (LQTS) and conduction disease. Although a great deal of work has been performed to explain how ...
Sridhar Arun - - 2008
Ventricular tachyarrhythmias are the most common cause of sudden cardiac death (SCD); a healed myocardial infarction increases the risk of SCD. We determined the contribution of specific repolarization abnormalities to ventricular tachyarrhythmias in a postinfarction model of SCD. For our methods, we used a postinfarction canine model of SCD, where ...
Brandes Axel - - 2008
During the past almost 50 years Holter monitoring has become an established non-invasive diagnostic tool in clinical electrophysiology. It allows ECG recording independent of stationary monitoring facilities during daily life and, therefore, contains much information. In the beginning the main interest was directed towards quantitative and qualitative assessment of arrhythmias, ...
Ben Caref E - - 2008
AIMS: The present study addresses the controversy regarding the 'primary' role of the subendocardial Purkinje network in triggering torsade de pointes (TdP) ventricular tachyarrhythmia (VAs) in the long QT syndrome (LQTS). METHODS AND RESULTS: We investigated the well-established canine anthopleurin-A (AP-A) surrogate model of LQT3 to study the role of ...
Ernest David - - 2008
OBJECTIVE: To report on a probable association between sibutramine and QT interval prolongation leading to ventricular fibrillation and cardiac arrest. CASE SUMMARY: A previously well 51-year-old woman with obesity but no other relevant past medical history or cardiac risk factors was prescribed sibutramine (initial dose 10 mg daily, increased to ...
Gelzer Anna R M - - 2008
Dynamically induced heterogeneities of repolarization may lead to wave-front destabilizations and initiation of ventricular fibrillation (VF). In a computer modeling study, we demonstrated that specific sequences of premature stimuli maximized dynamically induced spatial dispersion of refractoriness and predisposed the heart to the development of conduction block. The purpose of this ...
Lazzerini Pietro Enea - - 2008
OBJECTIVE: Reports suggest that infliximab (IFX) may be associated with life-threatening tachyarrhythmias and bradyarrhythmias. We evaluated the prevalence of cardiac rhythm disorders during acute infusion of IFX in a prospective, single-blind, placebo-controlled crossover study of patients with chronic arthritis. Effects of the drug on measures of arrhythmia risk such as ...
Gunes Yilmaz - - 2008
BACKGROUND: P-wave dispersion (PWD) is a new parameter for the assessment of risk of atrial fibrillation and has been reported to be increased in heart failure. Diurnal variation of the PWD has been reported in patients with coronary artery disease (CAD). QT dispersion (QTD) has also a circadian variation. In ...
Moss Arthur J - - 2008
One form of the hereditary long-QT syndrome, LQT3-Delta KPQ, is associated with sustained inward sodium current during membrane depolarization. Ranolazine reduces late sodium channel current, and we hypothesized that ranolazine would have beneficial effects on electrical and mechanical cardiac function in LQT3 patients with the SCN5A-DeltaKPQ mutation. We assessed the ...
Aygul Nazif - - 2009
Carvedilol and bisoprolol reduce QT dispersion (QTD) in chronic heart failure (CHF). However, it is unclear whether there is a difference between the effects of the two drugs. The aim of the present study was to compare the long-term effects of carvedilol and bisoprolol on QTD in patients with CHF. ...
KHARIN S N - - 2009
Effects of ectopic pacing on left ventricular repolarization were studied in six anesthetized open-chest chickens. In each animal, unipolar electrograms were acquired from as many as 98 sites with 14 plunge needles (seven transmural locations between epicardium and endocardium in each needle). Activation-recovery intervals (ARIs), corrected to the cycle length, ...
Roepke Torsten K - - 2008
Mutations in human KCNE2, which encodes the MiRP1 potassium channel ancillary subunit, associate with long QT syndrome (LQTS), a defect in ventricular repolarization. The precise cardiac role of MiRP1 remains controversial, in part, because it has marked functional promiscuity in vitro. Here, we disrupted the murine kcne2 gene to define ...
Baumert Mathias - - 2008
Suggestions were made that increased myocardial sympathetic activity is reflected by elevated QT variability (dynamic changes in QT interval duration). However, the relationship between QT variability and the amount of norepinephrine released from the cardiac sympathetic terminals is unknown. We thus attempted to assess this relationship. The study was performed ...
Barbosa Eduardo C - - 2008
BACKGROUND: The electrocardiogram (ECG) of the athlete displays particular characteristics as a consequence of both electrophysiological and autonomic remodeling of the heart that follows continued physical training. However, doubts persist on how these changes directly interact during ventricular activation and repolarization ultimately affecting surface ECG waveforms in athletes. OBJECTIVE: This ...
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 ...
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