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Kozmann Gy?rgy - - 2010
To improve malignant arrhythmia risk stratification, the causal and random components of spatiotemporal dynamics of heart rate (RR distances), ventricular depolarization sequence, and repolarization disparity were studied based on body surface potential map records taken for 5 minutes, in resting, supine position on 14 healthy subjects (age range, 20-65 years) ...
Watanabe Ichiro - - 2010
A 46-year-old man with type II Brugada electrocardiogram pattern changed to a type I Brugada type electrocardiogram pattern by class I antiarrhythmic drug (pilsicainide) underwent electrophysiologic study. Ventricular fibrillation was induced by double extrastimuli from the right ventricular (RV) apex. Monophasic action potentials (MAPs) were then recorded from the high ...
Fossa Anthony A - - 2010
Historically, the heart rate corrected QT (QTc) interval has been the standard method to assess for impaired ventricular repolarization, particularly for drug development. However, QTc does not reflect changes in autonomic state or QT-RR hysteresis which can also affect the interpretation of arrhythmogenic risk. With the advent of more accurate ...
Crotti Lia - - 2010
The Short QT Syndrome is a recently described new genetic disorder, characterized by abnormally short QT interval, paroxysmal atrial fibrillation and life threatening ventricular arrhythmias. This autosomal dominant syndrome can afflict infants, children, or young adults; often a remarkable family background of cardiac sudden death is elucidated. At electrophysiological study, ...
Kanu Uche U Department of Biomedical Engineering, Cornell University, Ithaca, NY, - - 2010
Cardiac action potential duration alternans is characterized by a beat-to-beat alternation in action potential waveform. Its presence has been putatively linked to the onset of lethal cardiac arrhythmias. Previous studies, which have been limited to cardiac Purkinje fibers, have shown that closed-loop alternans control techniques, which apply a succession of ...
Nahshoni Eitan - - 2010
Increased QT dispersion (QTd) reflects cardiac autonomic imbalance and indicates elevated risk for cardiac arrhythmias. In the present study, we assessed heart rate, QT and corrected QT intervals, and QTd in 20 acutely ill bulimia nervosa adolescent inpatients on admission and discharge. A significant decrease in QTd was found between ...
Chiladakis John - - 2010
BACKGROUND: There is a continuing debate about the optimal method for QT interval adjustment to heart rate changes. We evaluated the heart rate dependence of QTc intervals derived from five different QT correction methods. METHODS: Study patients (n = 123, age 68 +/- 11 years) were dual-chamber device recipients with ...
Mulcahy James - - 2010
BACKGROUND AND OBJECTIVE: Acute stroke patients have a greater QT interval (QT) and QT interval dispersion than case controls, but evidence for a causal association between stroke and electrocardiogram (ECG) changes is limited because studies examined QT interval after stroke only. This retrospective observational study examined the change in QT ...
Khan Jamal Nasir - - 2010
AIMS: Therapeutic hypothermia (TH) is used in neuroprotection following cardiac arrest due to ventricular tachycardia (VT) and ventricular fibrillation (VF). Accidental hypothermia is itself known to cause prolongation of the corrected QT interval (QTc). QTc prolongation can cause polymorphic VT and VF. If this also occurs in TH, it may ...
Shirafuji Seiko - - 2010
Dysregulation of autonomic nervous system function and impaired homogeneity of myocardial repolarization are 2 important mechanisms for the genesis of ventricular arrhythmias in nonalcoholic subjects. Our previous study suggested that acute ethanol withdrawal promoted the shift of cardiac sympathovagal balance toward sympathetic predominance and reduced the vagal tone, which were ...
Galetta F - - 2010
The aim of the present study was to evaluate the effect of subclinical hyperthyroidism (SHT) on cardiovascular autonomic function and ventricular repolarization. Thirty subjects (25 females; mean age 49.6 ± 9.8 years) with SHT, as judged by reduced TSH serum levels and normal free T4 and T3 serum levels, and ...
Sicouri Serge S Masonic Medical Research Laboratory, Utica, New York 13501, USA. - - 2010
This study was designed to quantitate transseptal dispersion of repolarization (DR) and delineate its role in arrhythmogenesis using the calcium agonist BayK 8644 to mimic the gain of function of calcium channel current responsible for Timothy syndrome. Amplification of transmural dispersion of repolarization (TDR) has been shown to contribute to ...
Osadchii Oleg E - - 2010
The ventricular action potential (AP) shortens exponentially upon a progressive reduction of the preceding diastolic interval. Steep electrical restitution slopes have been shown to promote wavebreaks, thus contributing to electrical instability. The present study was designed to assess the predictive value of electrical restitution in hypokalemia-induced arrhythmogenicity. We recorded monophasic ...
Nishizawa Shinya - - 2009
We describe a case of isolated adrenocorticotropic hormone deficiency that showed ventricular fibrillation associated with QT prolongation. A 72-year-old man was admitted because of consciousness disorder caused by severe hypoglycemia. On the second hospital day, QT intervals were unexpectedly prolonged and ventricular fibrillation occurred. Electrical defibrillation was performed and restored ...
Metcalf Cameron S - - 2009
Status epilepticus (SE) is a seizure or series of seizures that persist for >30 min and often results in mortality. Death rarely occurs during or immediately following seizure activity, but usually within 30 days. Although ventricular arrhythmias have been implicated in SE-related mortality, the effects of this prolonged seizure activity ...
Tadros Rafik - - 2009
The atrioventricular (AV) node filters atrial impulses. Underlying rate-dependent refractory properties are assessed with the effective (ERPN; longest nonconducted atrial cycle length) and functional (FRPN; shortest His bundle cycle) refractory period determined with premature protocols at different basic rates. Fast rates prolong ERPN and shorten FRPN, but these effects vary ...
Piorecka-Makula Anna - - 2009
BACKGROUND: Hypertrophied and ischemic cardiac muscle in patients with aortic valve stenosis becomes a potential source of ventricular cardiac arrhythmia that can lead to sudden death. Arrhythmia is associated with an abnormal duration of the action potential in a cardiac muscle cell. The aim of this prospective study was to ...
Kim Nan Hee - - 2010
OBJECTIVES: Understanding why prolonged Bazett-corrected QT interval (QTc) is a risk factor for mortality is difficult, because QTc is positively correlated with heart rate. To optimally distinguish the effects of QT interval and heart rate on mortality, QT interval and heart rate were modeled separately and jointly in Pima Indians. ...
Yelken Birg?l - - 2009
OBJECTIVE: Carbon monoxide (CO) poisoning is known to cause myocardial toxicity and life threatening arrhythmias. QT interval measured from electrocardiogram is an indirect measure of the heterogeneity of ventricular repolarization, which may contribute to ventricular arrhythmias. The purpose of the study was to investigate whether the carboxyhemoglobin (COHb) level may ...
Voulgari Christina - - 2010
Metabolic syndrome (MetS) is a clustering of cardiovascular risk factors recently associated with left ventricular dysfunction. Limited data exist on the association between MetS and ventricular arrhythmogenicity. This study examined differences in ventricular arrhythmogenicity assessed by classic (QT interval) and newer (spatial QRS-T angle [spQRS-Ta]) electrocardiographic markers in subjects with ...
Pecori Giraldi F - - 2010
Symptoms and signs of male hypogonadism span all organ systems, including the cardiovascular apparatus. The electrocardiographic QT interval reflects cardiac ventricular repolarization and, if prolonged, increases the risk of malignant arrhythmias. QT interval duration is similar in boys and girls during childhood, but shortens in males after puberty and experimental ...
Kim Jae Hee - - 2009
A 24-year-old woman presented to the department of plastic surgery for surgical excision of a nevus on her nose. Although her history failed to reveal any cardiac disease, her pre-operative electrocardiogram (ECG) showed an extremely prolonged QT interval of up to 528 msec. Repeated history-taking after admission revealed three syncopal ...
Couderc Jean-Philippe - - 2009
Cellular and macroelectrical instability within the heart ventricles during repolarization is described as a potential triggering mechanism of life-threatening arrhythmias. Although this phenomenon was observed in animal and in vitro studies, significant efforts have been put into the design of computerized technologies to quantify very subtle variations of the repolarization ...
Tereshchenko Larisa G - - 2009
We previously showed that increased intracardiac repolarization lability predicts life-threatening ventricular arrhythmias in patients with structural heart disease. Patients with structural heart disease frequently take antiarrhythmic drugs (AADs), which directly affect repolarization. The effect of AADs on the predictive value of repolarization lability is unknown. We hypothesized that increased intracardiac ...
Ziv Ohad O Cardiovascular Research Center, Division of Cardiology, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI 02903, - - 2009
Enhanced dispersion of repolarization has been proposed as an important mechanism in long QT related arrhythmias. Dispersion can be dynamic and can be augmented with the occurrence of spatially out-of-phase action potential duration (APD) alternans (discordant alternans; DA). We investigated the role of tissue heterogeneity in generating DA using a ...
Aslanian Robert - - 2009
In the late 1980's reports linking the non-sedating antihistamines terfenadine and astemizole with torsades de pointes, a form of ventricular tachyarrhythmia that can degenerate into ventricular fibrillation and sudden death, appeared in the clinical literature. A substantial body of evidence demonstrates that the arrhythmogenic effect of these cardiotoxic antihistamines, as ...
Dobson Craig P - - 2009
BACKGROUND: Previous studies have shown that increased temporal variability of repolarization, as reflected by QT interval variability measured for 10 minutes, predicted spontaneous ventricular arrhythmias in implantable cardioverter defribrillator patients, but it is unclear how these measures perform in 24-hour recordings. METHODS: Twenty-four-hour digital Holter recordings from 372 subjects with ...
Haarmark Christian - - 2009
INTRODUCTION: The Tpeak-Tend interval (TpTe) has been linked to increased arrhythmic risk. TpTe was investigated before and after primary percutaneous coronary intervention (pPCI) in patients with ST-segment elevation myocardial infarction (STEMI). METHOD: Patients with first-time STEMI treated with pPCI were included (n = 101; mean age 62 years; range 39-89 ...
Guo Liang - - 2009
INTRODUCTION: Cardiac liabilities represent a major cause of recent withdrawal of marketed drugs and also for the high attrition rate evidenced during late stage drug development. To identify molecules with potential cardiovascular risks early in drug development, a screening model of ex vivo Langendorff hearts has been validated with 26 ...
Osaka Toshiyuki - - 2009
BACKGROUND: Bepridil is highly effective in the treatment of atrial fibrillation, but its clinical usefulness is limited by a potential risk for the drug-induced Torsades de pointes (TdP) in association with its Class III action. METHODS AND RESULTS: Monophasic action potentials (MAPs) were recorded from the right ventricular outflow tract ...
Feng Li - - 2009
BACKGROUND: Shen song Yang xin (SSYX) is a compound of Chinese medicine with the effect of increasing heart rate (HR). This study aimed to evaluate its electrophysiological properties at heart and cellular levels. METHODS: The Chinese miniature swines were randomly assigned to two groups, administered with SSYX or placebo for ...
Caselli Luigi - - 2009
BACKGROUND: Standard 12-lead electrocardiogram (ECG) has several limitations in solving the differential diagnosis between physiologic left ventricular hypertrophy (PLVH) and hypertrophic cardiomyopathy (HCM), given the high rate of false-positive results in athletes. The aim of this study was to assess the usefulness of several arrhythmic risk indexes in differentiating PLVH ...
Ardhanari Sivakumar - - 2009
Hypokalemia, as an adverse consequence of severe alkalosis, can prolong QT interval and cause torsades de pointes. This report describes a rare case of central neurogenic hyperventilation as a result of brainstem infarct, presenting primarily with refractory ventricular tachyarrhythmia due to secondary hypokalemia.
Lambiase P D - - 2009
Two principal mechanisms are thought to be responsible for Brugada syndrome (BS): (1) right ventricular (RV) conduction delay and (2) RV subepicardial action potential shortening. This in vivo high-density mapping study evaluated the conduction and repolarization properties of the RV in BS subjects. A noncontact mapping array was positioned in ...
Friedman Peter L - - 2010
An 82-year-old woman with persistent atrial fibrillation underwent successful electrical cardioversion and was begun on sotalol. After 3 days of in-hospital observation she had only mild lengthening of the QT interval. Two weeks later in clinic, the day after her husband's unexpected death, she was noted to have profound QT ...
Kim Jae Kwon - - 2009
During coronary angiography and interventional procedures, catheters that are engaged in a coronary ostium are routinely flushed, typically with normal saline, to expel blood from the catheter or to inject a pharmacologic agent. Saline contains sodium and chloride ions. Such injections may affect the electrophysiologic properties of the myocardium; however, ...
Akylbekova Ermeg L EL Jackson State University, Jackson Heart Study, Jackson, Miss, - - 2009
Electrocardiographic QT interval prolongation is a risk factor for sudden cardiac death and drug-induced arrhythmia. The clinical correlates and heritability of QT interval duration in blacks have not been well studied despite their higher risk for sudden cardiac death compared with non-Hispanic whites. We sought to investigate potential correlates of ...
Takaya Tomofumi - - 2009
An 83-year-old female, who had a history of anterior myocardial infarction, was treated for Alzheimer's disease with donepezil. She suffered from repeated diarrhea and vomiting, and experienced syncope. She was admitted to our hospital and was diagnosed with acute colitis and syncope. On admission, her heart rate was 54 beats/min ...
Lux Robert L - - 2009
We conducted a retrospective study of a set of previously published electrocardiographic data to investigate the possible direct association between levels of particulate air pollution and changes in ventricular repolarization -- the cardiac electrophysiologic process that manifests itself as the T wave* of the electrocardiogram (ECG) and that is definitively ...
Cheng Alan - - 2009
INTRODUCTION: Ibutilide has been shown to prolong repolarization times and increase the risk of ventricular tachyarrhythmias particularly in patients with structural heart disease. The mechanisms underlying its proarrhythmic effects remain incompletely understood. We sought to define the effects of ibutilide on the temporal lability of ventricular repolarization in patients with ...
Lewicke Aaron - - 2009
In the present study, we have retrospectively analyzed the corrected QT (QTc) interval before spontaneous episodes of sudden cardiac arrest in patients with a wearable cardioverter defibrillator. Corrected QT interval was measured for all normal beats from 32 recordings of baseline rhythm and compared to normal rhythm before a paired ...
Couderc Jean-Philippe - - 2009
Ventricular repolarization (VR) is a crucial step in cardiac electrical activity because it corresponds to a recovery period setting the stage for the next heart contraction. Small perturbations of the VR process can predispose an individual to lethal arrhythmias. In this review, I aim to provide an overview of the ...
Ederhy Stephane - - 2009
Among toxicities associated with molecular targeted agents (MTA), cardiovascular toxicities remain largely unknown or underestimated. Their frequency is variable and dependent on the compound. A high incidence of hypertension, symptomatic or asymptomatic left ventricular systolic dysfunction, acute coronary syndrome, arterial and venous thrombosis has been observed in patients receiving MTA. ...
Cygankiewicz Iwona - - 2009
The population of patients with heart failure (HF) and mild to moderate left ventricular (LV) dysfunction is growing, and mortality remains high. There is a need for better risk stratification of patients who might benefit from primary prevention of mortality. This study aimed to evaluate the prognostic value of Holter-based ...
Pfeufer Arne A Institute of Human Genetics, Helmholtz Center Munich, Germany. - - 2009
The QT interval, a measure of cardiac repolarization, predisposes to ventricular arrhythmias and sudden cardiac death (SCD) when prolonged or shortened. A common variant in NOS1AP is known to influence repolarization. We analyze genome-wide data from five population-based cohorts (ARIC, KORA, SardiNIA, GenNOVA and HNR) with a total of 15,842 ...
Newton-Cheh Christopher C Center for Human Genetic Research, Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA. - - 2009
QT interval duration, reflecting myocardial repolarization on the electrocardiogram, is a heritable risk factor for sudden cardiac death and drug-induced arrhythmias. We conducted a meta-analysis of three genome-wide association studies in 13,685 individuals of European ancestry from the Framingham Heart Study, the Rotterdam Study and the Cardiovascular Health Study, as ...
Voss Frederik - - 2009
BACKGROUND: Transmural heterogeneity in ventricular repolarization demonstrated in vitro has been difficult to confirm in vivo. Whether this discrepancy reflects a physiological phenomenon or a methodological problem remains a vivid matter of debate despite a plethora of experimental work. Therefore, we have measured the relevant electrophysiological parameters first in vivo ...
Sun Ping - - 2009
The zebrafish (Danio rerio) is an emerging model for cardiovascular research. The zebrafish heart regenerates after 20% ventricular amputation. However, assessment of the physiological responses during heart regeneration has been hampered by the small size of the heart and the necessity of conducting experiments in an aqueous environment. We developed ...
Owczuk Radoslaw - - 2009
1. QT interval prolongation is associated with a risk of life-threatening cardiac arrhythmias. We examined whether reversible adrenergic blockade of the heart obtained through thoracic epidural anaesthesia influences cardiac repolarisation and thus confers an antiarrhythmic effect. 2. Fifty-two males between 28 and 65 years of age were included in the ...
Kurokawa Junko - - 2009
Regulation of cardiac ion channels by sex hormones accounts for gender differences in susceptibility to arrhythmias associated with QT prolongation (TdP). Women are more prone to develop TdP than men with either congenital or acquired long-QT syndrome. The risk of drug-induced TdP varies during the menstrual cycle, suggesting that dynamic ...
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