Metabolic Syndrome Remodels Electrical Activity of the Sinoatrial Node and Produces Arrhythmias in Rats

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Albarado-Ibañez, Alondra; Avelino-Cruz, José Everardo; Velasco, Myrian; Torres-Jácome, Julián; Hiriart, Marcia

2013-01-01

In the last ten years, the incidences of metabolic syndrome and supraventricular arrhythmias have greatly increased. The metabolic syndrome is a cluster of alterations, which include obesity, hypertension, hypertriglyceridemia, glucose intolerance and insulin resistance, that increase the risk of developing, among others, atrial and nodal arrhythmias. The aim of this study is to demonstrate that metabolic syndrome induces electrical remodeling of the sinus node and produces arrhythmias. We induced metabolic syndrome in 2-month-old male Wistar rats by administering 20% sucrose in the drinking water. Eight weeks later, the rats were anesthetized and the electrocardiogram was recorded, revealing the presence of arrhythmias only in treated rats. Using conventional microelectrode and voltage clamp techniques, we analyzed the electrical activity of the sinoatrial node. We observed that in the sinoatrial node of “metabolic syndrome rats”, compared to controls, the spontaneous firing of all cells decreased, while the slope of the diastolic depolarization increased only in latent pacemaker cells. Accordingly, the pacemaker currents If and Ist increased. Furthermore, histological analysis showed a large amount of fat surrounding nodal cardiomyocytes and a rise in the sympathetic innervation. Finally, Poincaré plot denoted irregularity in the R-R and P-P ECG intervals, in agreement with the variability of nodal firing potential recorded in metabolic syndrome rats. We conclude that metabolic syndrome produces a dysfunction SA node by disrupting normal architecture and the electrical activity, which could explain the onset of arrhythmias in rats. PMID:24250786

β1-Adrenoceptor blocker aggravated ventricular arrhythmia.

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Wang, Yan; Patel, Dimpi; Wang, Dao Wu; Yan, Jiang Tao; Hsia, Henry H; Liu, Hao; Zhao, Chun Xia; Zuo, Hou Juan; Wang, Dao Wen

2013-11-01

To assess the impact of β1 -adrenoceptor blockers (β1 -blocker) and isoprenaline on the incidence of idiopathic repetitive ventricular arrhythmia that apparently decreases with preprocedural anxiety. From January 2010 to July 2012, six patients were identified who had idiopathic ventricular arrhythmias that apparently decreased (by greater than 90%) with preprocedural anxiety. The number of ectopic ventricular beats per hour (VPH) was calculated from Holter or telemetry monitoring to assess the ectopic burden. The mean VPH of 24 hours from Holter before admission (VPH-m) was used as baseline (100%) for normalization. β1 -Blockers, isoprenaline, and/or aminophylline were administrated successively on the ward and catheter lab to evaluate their effects on the ventricular arrhythmias. Among 97 consecutive patients with idiopathic ventricular arrhythmias, six had reduction in normalized VPHs in the hour before the scheduled procedure time from (104.6 ± 4.6%) to (2.8 ± 1.6%) possibly due to preprocedural anxiety (P < 0.05), then increased to (97.9 ± 9.7%) during β1 -blocker administration (P < 0.05), then quickly reduced to (1.6 ± 1.0%) during subsequent isoprenaline infusion. Repeated β1 -blocker quickly counteracted the inhibitory effect of isoprenaline, and VPHs increased to (120.9 ± 2.4%) from (1.6 ± 1.0%; P < 0.05). Isoprenaline and β1 -blocker showed similar effects on the arrhythmias in catheter lab. In some patients with structurally normal heart and ventricular arrhythmias there is a marked reduction of arrhythmias associated with preprocedural anxiety. These patients exhibit a reproducible sequence of β1 -blocker aggravation and catecholamine inhibition of ventricular arrhythmias, including both repetitive ventricular premature beats and monomorphic ventricular tachycardia. ©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.

Alcohol, cardiac arrhythmias and sudden death.

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Kupari, M; Koskinen, P

1998-01-01

Studies in experimental animals have shown varying and apparently opposite effects of alcohol on cardiac rhythm and conduction. Given acutely to non-alcoholic animals, ethanol may even have anti-arrhythmic properties whereas chronic administration clearly increases the animals' susceptibility to cardiac arrhythmias. Chronic heavy alcohol use has been incriminated in the genesis of cardiac arrhythmias in humans. The evidence has come from clinical observations, retrospective case-control studies, controlled studies of consecutive admissions for arrhythmias, and prospective epidemiological investigations. Furthermore, electrophysiological studies have shown that acute alcohol administration facilitates the induction of tachyarrhythmias in selected heavy drinkers. The role of alcohol appears particularly conspicuous in idiopathic atrial fibrillation. Occasionally, ventricular tachyarrhythmias have also been provoked by alcohol intake. Several lines of evidence suggest that heavy drinking increases the risk of sudden cardiac death with fatal arrhythmia as the most likely mechanism. According to epidemiological studies this effect appears most prominent in middle-aged men and is only partly explained by confounding traits such as smoking and social class. The basic arrhythmogenic effects of alcohol are still insufficiently delineated. Subclinical heart muscle injury from chronic heavy use may be instrumental in producing patchy delays in conduction. The hyperadrenergic state of drinking and withdrawal may also contribute, as may electrolyte abnormalities, impaired vagal heart rate control, repolarization abnormalities with prolonged QT intervals and worsening of myocardial ischaemia or sleep apnoea. Most of what we know about alcohol and arrhythmias relates to heavy drinking. The effect of social drinking on clinical arrhythmias in non-alcoholic cardiac patients needs to be addressed further.

Arrhythmia risk in liver cirrhosis

Institute of Scientific and Technical Information of China (English)

Ioana Mozos

2015-01-01

Interactions between the functioning of the heart andthe liver have been described, with heart diseasesaffecting the liver, liver diseases affecting the heart,and conditions that simultaneously affect both. Theheart is one of the most adversely affected organs inpatients with liver cirrhosis. For example, arrhythmiasand electrocardiographic changes are observed inpatients with liver cirrhosis. The risk for arrhythmia isinfluenced by factors such as cirrhotic cardiomyopathy,cardiac ion channel remodeling, electrolyte imbalances,impaired autonomic function, hepatorenal syndrome, metabolic abnormalities, advanced age, inflammatory syndrome, stressful events, impaired drug metabolism and comorbidities. Close monitoring of cirrhotic patients is needed for arrhythmias, particularly when QT intervalprolonging drugs are given, or if electrolyte imbalances or hepatorenal syndrome appear. Arrhythmia risk may persist after liver transplantation due to possible QT interval prolongation, persistence of the parasympathetic impairment, post-transplant reperfusion and chronic immunosuppression, as well as consideration of the fact that the transplant itself is a stressful event for the cardiovascular system. The aims of the present article were to provide a review of the most important data regarding the epidemiology, pathophysiology, and biomarkers of arrhythmia risk in patients with liver cirrhosis, to elucidate the association with long-term outcome, and to propose future research directions.

Growth factor-induced mobilization of cardiac progenitor cells reduces the risk of arrhythmias, in a rat model of chronic myocardial infarction.

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Leonardo Bocchi

Full Text Available Heart repair by stem cell treatment may involve life-threatening arrhythmias. Cardiac progenitor cells (CPCs appear best suited for reconstituting lost myocardium without posing arrhythmic risks, being commissioned towards cardiac phenotype. In this study we tested the hypothesis that mobilization of CPCs through locally delivered Hepatocyte Growth Factor and Insulin-Like Growth Factor-1 to heal chronic myocardial infarction (MI, lowers the proneness to arrhythmias. We used 133 adult male Wistar rats either with one-month old MI and treated with growth factors (GFs, n = 60 or vehicle (V, n = 55, or sham operated (n = 18. In selected groups of animals, prior to and two weeks after GF/V delivery, we evaluated stress-induced ventricular arrhythmias by telemetry-ECG, cardiac mechanics by echocardiography, and ventricular excitability, conduction velocity and refractoriness by epicardial multiple-lead recording. Invasive hemodynamic measurements were performed before sacrifice and eventually the hearts were subjected to anatomical, morphometric, immunohistochemical, and molecular biology analyses. When compared with untreated MI, GFs decreased stress-induced arrhythmias and concurrently prolonged the effective refractory period (ERP without affecting neither the duration of ventricular repolarization, as suggested by measurements of QTc interval and mRNA levels for K-channel α-subunits Kv4.2 and Kv4.3, nor the dispersion of refractoriness. Further, markers of cardiomyocyte reactive hypertrophy, including mRNA levels for K-channel α-subunit Kv1.4 and β-subunit KChIP2, interstitial fibrosis and negative structural remodeling were significantly reduced in peri-infarcted/remote ventricular myocardium. Finally, analyses of BrdU incorporation and distribution of connexin43 and N-cadherin indicated that cytokines generated new vessels and electromechanically-connected myocytes and abolished the correlation of infarct size with deterioration

Arrhythmias in type 2 diabetes mellitus

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Gaurav Agarwal

2017-01-01

Full Text Available Chronic hyperglycaemia of Type 2 diabetes mellitus causes long term damage to heart resulting in coronary artery disease (CAD, myocardial infarction (MI, congestive heart failure (CHF, and sudden death from arrhythmias. AIMS: To study the prevalence of different types of arrhythmias in T2DM, particularly in association with Cardiac Autonomic Neuropathy (CAN. METHODS: A cross-sectional study including 100 patients of Type 2 Diabetes Mellitus (T2DM presenting with cardiac arrhythmias, was done at our hospital over 2 years. Detailed history along with physical examination and tests for CAN were done. Routine investigations along with echocardiography, stress test, Holter monitoring were done. RESULTS: Sinus Tachycardia (ST was the commonest arrhythmia, found in 32% of patients. 20% had Complete Heart Block (CHB, 15% had Sinus Bradycardia (SB, and 15% had Atrial Fibrillation (AF. Ventricular Premature Complex (VPC was found in 10% and 3% had Atrial Premature Complex (APC. 3% had first degree AV block, whereas 1% had Paroxysmal Supra Ventricular Tachycardia (PSVT, and another 1% had Ventricular Tachycardia (VT. Poorly controlled diabetes and co-morbidities was associated with higher incidence of arrhythmias. 62% of patients had prolonged QTc, majority of which had CAN. Most of the patients responded to standard therapy.

Arrhythmia and exercise intolerance in Fontan patients

DEFF Research Database (Denmark)

Idorn, L; Juul, K; Jensen, A S

2013-01-01

BACKGROUND: Long-term survival after the Fontan procedure shows excellent results but is associated with a persistent risk of arrhythmias and exercise intolerance. We aimed to analyze the current burden of clinically relevant arrhythmia and severe exercise intolerance in Danish Fontan patients...... and estimated to 99.1% per year. Prevalence of clinically relevant arrhythmia and severe exercise intolerance increased significantly with age and was found in 32% and 85% of patients ≥20years, respectively. Thus, from survival data and logistic regression models the future prevalence of patients, clinically...... relevant arrhythmia and severe exercise intolerance were estimated, revealing a considerable augmentation. Furthermore, resting and maximum cardiac index, resting stroke volume index and pulmonary diffusing capacity decreased significantly with age while diastolic and systolic ventricular function...

Burden of arrhythmia in recreational marijuana users.

Science.gov (United States)

Desai, Rupak; Patel, Upenkumar; Deshmukh, Abhishek; Sachdeva, Rajesh; Kumar, Gautam

2018-03-27

Marijuana or Cannabis is extensively used as a recreational substance globally. Case reports have reported cardiac arrhythmias immediately following recreational marijuana use. However, the burden of arrhythmias in hospitalized marijuana users have not been evaluated through prospective or cross-sectional studies. Therefore, we planned to measure temporal trends of the frequency of arrhythmias in hospitalized marijuana users using National Inpatient Sample (NIS) database in the United States. Copyright © 2017 Elsevier B.V. All rights reserved.

An assessment of the energetic flows in a commercial PEM fuel-cell system

International Nuclear Information System (INIS)

Jovan, Vladimir; Perne, Matija; Petrovcic, Janko

2010-01-01

Some primary issues have not yet been fully investigated on the way towards the commercialization of fuel-cell-based systems (FCS), e.g., their actual efficiency, reliability, safety, degradation, maintainability, etc. This article deals with an estimation of the real energetic flows and the corresponding electrical efficiency of a commercial proton-exchange-membrane fuel-cell hydrogen-fed generator set (PEMFCS). The fuel-cell power system considered here is planned to be the source of both electrical and thermal energy in a mobile dwelling container unit with in-built fuel-cell-based cogeneration system, and for the design of a cogeneration unit the actual amount of disposable energy from the PEMFC unit should be estimated. The assessment of the actual energetic flows, the disposable energy and the consequent electrical efficiency of the case-study PEMFCS is carried out using commercial technical data for the PEMFCS.

Cardiac arrhythmia as initial presentation of aneurysmal subarachnoid hemorrhage

NARCIS (Netherlands)

van der Kleij, FGH; Henselmans, JML; van de Loosdrecht, AA

1999-01-01

Cardiac arrhythmia and sudden death are most frequently caused by preexisting heart disease. Rarely, cardiac arrhythmia is a first symptom of an acute neurological event. We describe a patient with asystole and other cardiac arrhythmias, as initial symptoms of acute aneurysmal subarachnoid

Obstructive sleep apnoea-hypopnoea and arrhythmias: new updates.

Science.gov (United States)

Vizzardi, Enrico; Sciatti, Edoardo; Bonadei, Ivano; D'Aloia, Antonio; Curnis, Antonio; Metra, Marco

2017-07-01

Obstructive sleep apnoea-hypopnoea (OSAH) is a prevalent condition characterized by repetitive pharyngeal collapse during sleep, leading to hypoxemia, hypercapnia, and persistent inspiratory efforts against an occluded airway until arousal. Several studies demonstrated that OSAH exerts acute and chronic effects on the cardiovascular system. Thus, although being a respiratory problem, the most important consequences of OSAH are cardiovascular, among which there are arrhythmias. The purpose of this review is to systematically analyse what has been recently published about the relationship between OSAH and every cardiac arrhythmia separately. We searched Pubmed, Scopus, Web of Science and Cochrane Collaboration databases for 'OSAHS arrhythmias', 'OSAH arrhythmias' and 'OSA arrhythmias'. We analyse 1298 articles and meta-analyses, excluding already edited reviews. Arrhythmias, especially of ventricular origin, are frequent in OSAH. Ventricular premature beats, couplets and ventricular tachycardia runs are even more frequent in patients suffering from heart failure. They may be due to left heart remodelling, overwork and ischaemia and can explain at least some sudden deaths occurring between midnight and 6 a.m. Sinus pauses and atrioventricular blocks are increased according to the severity of the disturbance and may be reduced by continuous positive airway pressure therapy, preventing pace-maker implantation. Finally, atrial fibrillation, resistance against antiarrhythmic drugs and recurrences after surgical procedures are strongly related to OSAH. Arrhythmias are frequent in OSAH. Treatment of OSAH may reduce some of them. An implantable cardioverter-defibrillator and continuous positive airway pressure should be considered in some patients.

Malignant Arrhythmia in Apical Ballooning Syndrome: Risk Factors and Outcomes

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Samuel J. Asirvatham

2008-08-01

Full Text Available Objectives: We sought to determine the frequency and outcomes with symptomatic arrhythmia in patients with apical ballooning syndrome (ABS. Methods: A retrospective review of the Mayo Clinic Angiography database was conducted to identify patients who met the Mayo criteria for ABS. Patients with documented arrhythmias formed the study group, and 31 randomly selected patients with ABS but without arrhythmia formed the control group.Results: Out of 105 patients identified with ABS, 6 (5.7% women aged 69 +/- 9 years experienced significant arrhythmia (ventricular fibrillation, asystole, 2 patients died, and 1 required permanent pacemaker implantation. When compared with controls, the study group showed no significant difference with respect to ECG characteristics (QT, QRS duration or axis except for R-R interval variability (see comments below (30.6±6 vs 14.5±17 p = 0.0004, QTc, and P-R interval. Patients without arrhythmia were more likely to be on beta-blocker therapy than the study population (33% vs 80.6% p = 0.02. Conclusion: Life-threatening arrhythmia is uncommon (5.7% with ABS despite marked, structural abnormalities. When arrhythmias do occur, the outcome is poor. Prominent variability in R-R intervals appears to be predictive of significant arrhythmias in ABS. The role of beta-blocker therapy in preventing arrhythmia with ABS requires further investigation.

Arrhythmia during extracorporeal shock wave lithotripsy.

Science.gov (United States)

Zeng, Z R; Lindstedt, E; Roijer, A; Olsson, S B

1993-01-01

A prospective study of arrhythmia during extracorporeal shock wave lithotripsy (ESWL) was performed in 50 patients, using an EDAP LT01 piezoelectric lithotriptor. The 12-lead standard ECG was recorded continuously for 10 min before and during treatment. One or more atrial and/or ventricular ectopic beats occurred during ESWL in 15 cases (30%). The occurrence of arrhythmia was similar during right-sided and left-sided treatment. One patient developed multifocal ventricular premature beats and ventricular bigeminy; another had cardiac arrest for 13.5 s. It was found that various irregularities of the heart rhythm can be caused even by treatment with a lithotriptor using piezoelectric energy to create the shock wave. No evidence was found, however, that the shock wave itself rather than vagal activation and the action of sedo-analgesia was the cause of the arrhythmia. For patients with severe underlying heart disease and a history of complex arrhythmia, we suggest that the ECG be monitored during treatment. In other cases, we have found continuous monitoring of oxygen saturation and pulse rate with a pulse oximeter to be perfectly reliable for raising the alarm when depression of respiration and vaso-vagal reactions occur.

Andrographolide inhibits arrhythmias and is cardioprotective in rabbits

OpenAIRE

Zeng, Mengliu; Jiang, Wanzhen; Tian, Youjia; Hao, Jie; Cao, Zhenzhen; Liu, Zhipei; Fu, Chen; Zhang, Peihua; Ma, Jihua

2017-01-01

Andrographolide has a protective effect on the cardiovascular system. To study its cardic-electrophysiological effects, action potentials and voltage-gated Na+ (INa), Ca2+ (ICaL), and K+ (IK1, IKr, Ito and IKur) currents were recorded using whole-cell patch clamp and current clamp techniques. Additionally, the effects of andrographolide on aconitine-induced arrhythmias were assessed on electrocardiograms in vivo. We found that andrographolide shortened action potential duration and reduced ma...

Sleep Apnea and Nocturnal Cardiac Arrhythmia: A Populational Study

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Fatima Dumas Cintra

2014-11-01

Full Text Available Background: The mechanisms associated with the cardiovascular consequences of obstructive sleep apnea include abrupt changes in autonomic tone, which can trigger cardiac arrhythmias. The authors hypothesized that nocturnal cardiac arrhythmia occurs more frequently in patients with obstructive sleep apnea. Objective: To analyze the relationship between obstructive sleep apnea and abnormal heart rhythm during sleep in a population sample. Methods: Cross-sectional study with 1,101 volunteers, who form a representative sample of the city of São Paulo. The overnight polysomnography was performed using an EMBLA® S7000 digital system during the regular sleep schedule of the individual. The electrocardiogram channel was extracted, duplicated, and then analyzed using a Holter (Cardio Smart® system. Results: A total of 767 participants (461 men with a mean age of 42.00 ± 0.53 years, were included in the analysis. At least one type of nocturnal cardiac rhythm disturbance (atrial/ventricular arrhythmia or beat was observed in 62.7% of the sample. The occurrence of nocturnal cardiac arrhythmias was more frequent with increased disease severity. Rhythm disturbance was observed in 53.3% of the sample without breathing sleep disorders, whereas 92.3% of patients with severe obstructive sleep apnea showed cardiac arrhythmia. Isolated atrial and ventricular ectopy was more frequent in patients with moderate/severe obstructive sleep apnea when compared to controls (p < 0.001. After controlling for potential confounding factors, age, sex and apnea-hypopnea index were associated with nocturnal cardiac arrhythmia. Conclusion: Nocturnal cardiac arrhythmia occurs more frequently in patients with obstructive sleep apnea and the prevalence increases with disease severity. Age, sex, and the Apnea-hypopnea index were predictors of arrhythmia in this sample.

Remote Arrhythmia Monitoring System Developed

Science.gov (United States)

York, David W.; Mackin, Michael A.; Liszka, Kathy J.; Lichter, Michael J.

2004-01-01

Telemedicine is taking a step forward with the efforts of team members from the NASA Glenn Research Center, the MetroHealth campus of Case Western University, and the University of Akron. The Arrhythmia Monitoring System is a completed, working test bed developed at Glenn that collects real-time electrocardiogram (ECG) signals from a mobile or homebound patient, combines these signals with global positioning system (GPS) location data, and transmits them to a remote station for display and monitoring. Approximately 300,000 Americans die every year from sudden heart attacks, which are arrhythmia cases. However, not all patients identified at risk for arrhythmias can be monitored continuously because of technological and economical limitations. Such patients, who are at moderate risk of arrhythmias, would benefit from technology that would permit long-term continuous monitoring of electrical cardiac rhythms outside the hospital environment. Embedded Web Technology developed at Glenn to remotely command and collect data from embedded systems using Web technology is the catalyst for this new telemetry system (ref. 1). In the end-to-end system architecture, ECG signals are collected from a patient using an event recorder and are transmitted to a handheld personal digital assistant (PDA) using Bluetooth, a short-range wireless technology. The PDA concurrently tracks the patient's location via a connection to a GPS receiver. A long distance link is established via a standard Internet connection over a 2.5-generation Global System for Mobile Communications/General Packet Radio Service (GSM/GPRS)1 cellular, wireless infrastructure. Then, the digital signal is transmitted to a call center for monitoring by medical professionals.

Cardiac arrhythmias in adult patients with asthma

DEFF Research Database (Denmark)

Warnier, Miriam J; Rutten, Frans H; Kors, Jan A

2012-01-01

OBJECTIVE: The pathogenesis of cardiac arrhythmias in asthma patients has not been fully elucidated. Adverse drug effects, particularly those of β2-mimetics, may play a role. The aim of this study was to determine whether asthma is associated with the risk of cardiac arrhythmias and electrocardio......OBJECTIVE: The pathogenesis of cardiac arrhythmias in asthma patients has not been fully elucidated. Adverse drug effects, particularly those of β2-mimetics, may play a role. The aim of this study was to determine whether asthma is associated with the risk of cardiac arrhythmias...... and electrocardiographic characteristics of arrhythmogenicity (ECG) and to explore the role of β2-mimetics. METHODS: A cross-sectional study was conducted among 158 adult patients with a diagnosis of asthma and 6303 participants without asthma from the cohort of the Utrecht Health Project-an ongoing, longitudinal, primary...... or flutter). Secondary outcomes were tachycardia, bradycardia, PVC, atrial fibrillation or flutter, mean heart rate, mean corrected QT (QTc) interval length, and prolonged QTc interval. RESULTS: Tachycardia and PVCs were more prevalent in patients with asthma (3% and 4%, respectively) than those without...

QTc-prolonging drugs and hospitalizations for cardiac arrhythmias

DEFF Research Database (Denmark)

De Bruin, Marie L; Hoes, Arno W; Leufkens, Hubert G M

2003-01-01

Cardiac arrhythmia as an adverse effect of noncardiac drugs has been an issue of growing importance during the past few years. In this population-based study, we evaluated the risk for serious cardiac arrhythmias during the use of several noncardiac QTc-prolonging drugs in day-to-day practice......, and subsequently focused on several specific groups of patients who could be extremely vulnerable for drug-induced arrhythmias. We performed a case-control study in which patients (cases), hospitalized for nonatrial cardiac arrhythmias from 1987 to 1998, were compared with their matched controls regarding current...... use of QTc-prolonging drugs. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using multivariate conditional logistic regression, adjusting for potential confounding factors. Data were obtained from the PHARMO record linkage system. We identified 501 cases, 39 of whom used QTc...

Electrical Signs predictors of malignant ventricular arrhythmias

International Nuclear Information System (INIS)

Aleman Fernandez, Ailema Amelia; Dorantes Sanchez, Margarita

2012-01-01

Recurrence of malignant ventricular arrhythmia is frequent in cardioverter-defibrillators related patients. The risk stratification is difficult, there are numerous electrocardiographic predictors but his sensibility and specificity are not absolute. The limit between normal and pathological is not defined, besides the complexity of ventricular arrhythmias. We expose different electrocardiographic predictors that can help to better individual risk stratification

[Idiopathic ventricular arrhythmia in children. Apropos of 24 cases].

Science.gov (United States)

Coeurderoy, A; Almange, C; Laurent, M; Biron, Y; Leborgne, P

1985-12-01

The severity and prognosis of idiopathic ventricular arrhythmias in childhood were studied in 24 patients (12 boys, 12 girls) with an average age of 8 years at the time of diagnosis of the arrhythmia. Investigations included clinical assessment and analysis of basal ECG (morphology of the arrhythmias) and dynamic recordings (Holter and exercise stress testing). The clinical course was followed for an average of 3.8 years. The patients were classified in two groups: monomorphic arrhythmias (Group I) and polymorphic arrhythmias (Group II). Group I was divided into 4 subgroups: isolated ventricular extrasystoles (IA), 11 patients; ventricular extrasystoles with bursts of ventricular tachycardia (IB), 6 patients; sustained ventricular tachycardia without intercritical extrasystoles (IC), 1 patient; accelerated idioventricular rhythm (ID), 2 patients. Subgroups IA, IB and ID were characterised by the absence of symptoms, the disappearance of the arrhythmia on exercise, the decreased efficacy of antiarrhythmic drugs and an excellent prognosis. Therapeutic abstention was the rule in these patients. Patients in Group IC were characterised by the variability of their symptoms, the absence of exercise induced arrhythmias, the need for treatment in most cases and a good long-term prognosis. Group II was divided into 2 subgroups: adrenergic polymorphic ventricular tachycardia (IIA), 2 patients, and non-adrenergic polymorphic ventricular tachycardia (IIB), 2 patients. Patients in Subgroup IIA were characterised by syncope on exercise or emotion, the need for betablocker therapy which considerably improved the patients symptoms but which did not usually prevent sudden death.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular function in patients with ventricular arrhythmias and aortic valve disease

International Nuclear Information System (INIS)

Santinga, J.T.; Kirsh, M.M.; Brady, T.J.; Thrall, J.; Pitt, B.

1983-01-01

Forty patients having aortic valve replacement were evaluated preoperatively for ventricular arrhythmia and left ventricular ejection fraction. Arrhythmias were classified as complex or simple using the Lown criteria on the 24-hour ambulatory electrocardiogram; ejection fractions were determined by radionuclide gated blood pool analysis and contrast angiography. The ejection fractions determined by radionuclide angiography were 59.1 +/- 13.1% for 26 patients with simple or no ventricular arrhythmias, and 43.9 +/- 20.3% for 14 patients with complex ventricular arrhythmias (p less than 0.01). Ejection fractions determined by angiography, available for 31 patients, were also lower in patients with complex ventricular arrhythmias (61.1 +/- 16.3% versus 51.4 +/- 13.4%; p less than 0.05). Seven of 9 patients showing conduction abnormalities on the electrocardiogram had complex ventricular arrhythmias. Eight of 20 patients with aortic stenosis had complex ventricular arrhythmias, while 2 of 13 patients with aortic insufficiency had such arrhythmias. It is concluded that decreased left ventricular ejection fraction, intraventricular conduction abnormalities, and aortic stenosis are associated with an increased frequency of complex ventricular arrhythmias in patients with aortic valve disease

Qt interval prolongation and ventricular arrhythmias in patients with chronic heart failure

International Nuclear Information System (INIS)

Sarwar, M.; Majeed, S.M.I.; Khan, M.A.; Majeed, S.M.

2014-01-01

To determine the association of QTc interval prolongation with ventricular arrhythmias in patients with chronic heart failure. Study Design: Descriptive study. Place and Duration of Study: This study was conducted at Armed Forces Institute of Cardiology/National Institute of Heart Diseases, Rawalpindi, Pakistan from April 2013 to August 2013. Patients and Methods: Fifty three heart failure patients were monitored for 48 hours using ambulatory holter electrocardiography recorders. Digital ECG data was analyzed for QTc interval along with frequency and severity of arrhythmias. Association of prolonged QTc interval with ventricular arrhythmias and severity of arrhythmias was analyzed. Results: Cardiac arrhythmias were observed in 79.2% patients. QT analysis revealed that 69.8% patients had prolonged QTc interval, 86.4% patients with prolonged QTc had ventricular arrhythmias. Of these 66% patients were found to have severe ventricular arrhythmias. Comparison of mean QTc interval of our study population with a reference value showed significantly higher QTc interval of our study group than the test value. Conclusion: Arrhythmia frequency and severity significantly increases with an increase in QTc interval in heart failure demonstrating association of prolonged QTc interval with high risk of severe ventricular arrhythmias and sudden cardiac death in chronic heart failure. (author)

QTc-prolonging drugs and hospitalizations for cardiac arrhythmias

NARCIS (Netherlands)

De Bruin, ML; Hoes, AW; Leufkens, HGM

2003-01-01

Cardiac arrhythmia as an adverse effect of noncardiac drugs has been an issue of growing importance during the past few years. In this population-based study, we evaluated the risk for serious cardiac arrhythmias during the use of several noncardiac QTc-prolonging drugs in day-to-day practice, and

Mitochondria and Energetic Depression in Cell Pathophysiology

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Stephan Zierz

2009-05-01

Full Text Available Mitochondrial dysfunction is a hallmark of almost all diseases. Acquired or inherited mutations of the mitochondrial genome DNA may give rise to mitochondrial diseases. Another class of disorders, in which mitochondrial impairments are initiated by extramitochondrial factors, includes neurodegenerative diseases and syndromes resulting from typical pathological processes, such as hypoxia/ischemia, inflammation, intoxications, and carcinogenesis. Both classes of diseases lead to cellular energetic depression (CED, which is characterized by decreased cytosolic phosphorylation potential that suppresses the cell’s ability to do work and control the intracellular Ca2+ homeostasis and its redox state. If progressing, CED leads to cell death, whose type is linked to the functional status of the mitochondria. In the case of limited deterioration, when some amounts of ATP can still be generated due to oxidative phosphorylation (OXPHOS, mitochondria launch the apoptotic cell death program by release of cytochrome c. Following pronounced CED, cytoplasmic ATP levels fall below the thresholds required for processing the ATP-dependent apoptotic cascade and the cell dies from necrosis. Both types of death can be grouped together as a mitochondrial cell death (MCD. However, there exist multiple adaptive reactions aimed at protecting cells against CED. In this context, a metabolic shift characterized by suppression of OXPHOS combined with activation of aerobic glycolysis as the main pathway for ATP synthesis (Warburg effect is of central importance. Whereas this type of adaptation is sufficiently effective to avoid CED and to control the cellular redox state, thereby ensuring the cell survival, it also favors the avoidance of apoptotic cell death. This scenario may underlie uncontrolled cellular proliferation and growth, eventually resulting in carcinogenesis.

Atrial Arrhythmias in Astronauts. Summary of a NASA Summit

Science.gov (United States)

Barr, Yael; Watkins, Sharmila; Polk, J. D.

2011-01-01

This slide presentation reviews the findings of a panel of heart experts brought together to study if atrial arrhythmias more prevalent in astronauts, and potential risk factors that may predispose astronauts to atrial arrhythmias. The objective of the panel was to solicit expert opinion on screening, diagnosis, and treatment options, identify gaps in knowledge, and propose relevant research initiatives. While Atrial Arrhythmias occur in approximately the same percents in astronauts as in the general population, they seem to occur at younger ages in astronauts. Several reasons for this predisposition were given: gender, hypertension, endurance training, and triggering events. Potential Space Flight-Related Risk factors that may play a role in precipitating lone atrial fibrillation were reviewed. There appears to be no evidence that any variable of the space flight environment increases the likelihood of developing atrial arrhythmias during space flight.

Frequency of Cardiac Arrhythmias in Patients with Aluminum Phosphide Poisoning

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Umair Aziz

2015-12-01

Full Text Available Background: Cardiac failure is the major lethal consequence of aluminum phosphide (AlP poisoning. This study was designed to determine the frequency of cardiac arrhythmias in patients with AlP poisoning. Methods: In this prospective cross-sectional study, patients with definitive history of AlP poisoning treated at emergency department of Allied Hospital Faisalabad, Faisalabad, Pakistan, from July 2013 to November 2014 were included. On admission, twelve-lead electrocardiogram (ECG was performed for all patients. During admission, all patients underwent continuous cardiac monitoring using a cardiac monitor. If an arrhythmia was suspected on the cardiac monitor, another ECG was obtained immediately.  Results: During the study period, 100 patients with AlP poisoning (63% men were treated at Allied Hospital Faisalabad. Mean age of the patients was 26.7 ± 7.9 years ranging from 16 to 54 years. Tachycardia was detected in 68 patients and bradycardia in 12 patients. Hypotension was observed in 75 patients. Eighty patients developed cardiac arrhythmia. The most frequent arrhythmia was atrial fibrillation (31% of patients followed by ventricular fibrillation (20%, ventricular tachycardia (17%, 3rd degree AV block (7% and 2nd degree AV block (5%. In total, 78 patients died, depicting a 78% mortality rate following wheat pill poisoning. Among those who died, seventy-one patients had cardiac arrhythmia. Comparison of death rate between patients with and without cardiac arrhythmia showed a significant difference (71/80 (88.8% vs. 7/20 (35%; P < 0.001.  Conclusion: Wheat pill poisoning causes a very high mortality, and circulatory collapse is the major cause of death among these patients. Most of the patients with AlP poisoning develop cardiac arrhythmias which are invariably life threatening. Early detection of cardiac disorders and proper management of arrhythmias may reduce mortalities.

Channelopathies - emerging trends in the management of inherited arrhythmias

NARCIS (Netherlands)

Chockalingam, Priya; Mizusawa, Yuka; Wilde, Arthur A. M.

2015-01-01

In spite of their relative rarity, inheritable arrhythmias have come to the forefront as a group of potentially fatal but preventable cause of sudden cardiac death in children and (young) adults. Comprehensive management of inherited arrhythmias includes diagnosing and treating the proband and

Acute effects of sex steroid hormones on susceptibility to cardiac arrhythmias: a simulation study.

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Pei-Chi Yang

2010-01-01

Full Text Available Acute effects of sex steroid hormones likely contribute to the observation that post-pubescent males have shorter QT intervals than females. However, the specific role for hormones in modulating cardiac electrophysiological parameters and arrhythmia vulnerability is unclear. Here we use a computational modeling approach to incorporate experimentally measured effects of physiological concentrations of testosterone, estrogen and progesterone on cardiac ion channel targets. We then study the hormone effects on ventricular cell and tissue dynamics comprised of Faber-Rudy computational models. The "female" model predicts changes in action potential duration (APD at different stages of the menstrual cycle that are consistent with clinically observed QT interval fluctuations. The "male" model predicts shortening of APD and QT interval at physiological testosterone concentrations. The model suggests increased susceptibility to drug-induced arrhythmia when estradiol levels are high, while testosterone and progesterone are apparently protective. Simulations predict the effects of sex steroid hormones on clinically observed QT intervals and reveal mechanisms of estrogen-mediated susceptibility to prolongation of QT interval. The simulations also indicate that acute effects of estrogen are not alone sufficient to cause arrhythmia triggers and explain the increased risk of females to Torsades de Pointes. Our results suggest that acute effects of sex steroid hormones on cardiac ion channels are sufficient to account for some aspects of gender specific susceptibility to long-QT linked arrhythmias.

Arrhythmia phenotype in mouse models of human long QT.

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Salama, Guy; Baker, Linda; Wolk, Robert; Barhanin, Jacques; London, Barry

2009-03-01

Enhanced dispersion of repolarization (DR) was proposed as a unifying mechanism, central to arrhythmia genesis in the long QT (LQT) syndrome. In mammalian hearts, K(+) channels are heterogeneously expressed across the ventricles resulting in 'intrinsic' DR that may worsen in long QT. DR was shown to be central to the arrhythmia phenotype of transgenic mice with LQT caused by loss of function of the dominant mouse K(+) currents. Here, we investigated the arrhythmia phenotype of mice with targeted deletions of KCNE1 and KCNH2 genes which encode for minK/IsK and Merg1 (mouse homolog of human ERG) proteins resulting in loss of function of I(Ks) and I(Kr), respectively. Both currents are important human K(+) currents associated with LQT5 and LQT2. Loss of minK, a protein subunit that interacts with KvLQT1, results in a marked reduction of I(Ks) giving rise to the Jervell and Lange-Nielsen syndrome and the reduced KCNH2 gene reduces MERG and I(Kr). Hearts were perfused, stained with di-4-ANEPPS and optically mapped to compare action potential durations (APDs) and arrhythmia phenotype in homozygous minK (minK(-/-)) and heterozygous Merg1 (Merg(+/-)) deletions and littermate control mice. MinK(-/-) mice has similar APDs and no arrhythmias (n = 4). Merg(+/-) mice had prolonged APDs (from 20 +/- 6 to 32 +/- 9 ms at the base, p mice (60% vs. 10%). A comparison of mouse models of LQT based on K(+) channel mutations important to human and mouse repolarization emphasizes DR as a major determinant of arrhythmia vulnerability.

Differential roles of two delayed rectifier potassium currents in regulation of ventricular action potential duration and arrhythmia susceptibility.

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Devenyi, Ryan A; Ortega, Francis A; Groenendaal, Willemijn; Krogh-Madsen, Trine; Christini, David J; Sobie, Eric A

2017-04-01

Arrhythmias result from disruptions to cardiac electrical activity, although the factors that control cellular action potentials are incompletely understood. We combined mathematical modelling with experiments in heart cells from guinea pigs to determine how cellular electrical activity is regulated. A mismatch between modelling predictions and the experimental results allowed us to construct an improved, more predictive mathematical model. The balance between two particular potassium currents dictates how heart cells respond to perturbations and their susceptibility to arrhythmias. Imbalances of ionic currents can destabilize the cardiac action potential and potentially trigger lethal cardiac arrhythmias. In the present study, we combined mathematical modelling with information-rich dynamic clamp experiments to determine the regulation of action potential morphology in guinea pig ventricular myocytes. Parameter sensitivity analysis was used to predict how changes in ionic currents alter action potential duration, and these were tested experimentally using dynamic clamp, a technique that allows for multiple perturbations to be tested in each cell. Surprisingly, we found that a leading mathematical model, developed with traditional approaches, systematically underestimated experimental responses to dynamic clamp perturbations. We then re-parameterized the model using a genetic algorithm, which allowed us to estimate ionic current levels in each of the cells studied. This unbiased model adjustment consistently predicted an increase in the rapid delayed rectifier K + current and a drastic decrease in the slow delayed rectifier K + current, and this prediction was validated experimentally. Subsequent simulations with the adjusted model generated the clinically relevant prediction that the slow delayed rectifier is better able to stabilize the action potential and suppress pro-arrhythmic events than the rapid delayed rectifier. In summary, iterative coupling of

Understand Your Risk for Arrhythmia

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... is likely monitoring your heart rhythm with regular EKGs ( electrocardiograms ). But arrhythmias that occur infrequently may not ... patient sheets Popular Articles 1 Understanding Blood Pressure Readings 2 Sodium and Salt 3 Heart Attack Symptoms ...

Facilitating arrhythmia simulation: the method of quantitative cellular automata modeling and parallel running

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Mondry Adrian

2004-08-01

Full Text Available Abstract Background Many arrhythmias are triggered by abnormal electrical activity at the ionic channel and cell level, and then evolve spatio-temporally within the heart. To understand arrhythmias better and to diagnose them more precisely by their ECG waveforms, a whole-heart model is required to explore the association between the massively parallel activities at the channel/cell level and the integrative electrophysiological phenomena at organ level. Methods We have developed a method to build large-scale electrophysiological models by using extended cellular automata, and to run such models on a cluster of shared memory machines. We describe here the method, including the extension of a language-based cellular automaton to implement quantitative computing, the building of a whole-heart model with Visible Human Project data, the parallelization of the model on a cluster of shared memory computers with OpenMP and MPI hybrid programming, and a simulation algorithm that links cellular activity with the ECG. Results We demonstrate that electrical activities at channel, cell, and organ levels can be traced and captured conveniently in our extended cellular automaton system. Examples of some ECG waveforms simulated with a 2-D slice are given to support the ECG simulation algorithm. A performance evaluation of the 3-D model on a four-node cluster is also given. Conclusions Quantitative multicellular modeling with extended cellular automata is a highly efficient and widely applicable method to weave experimental data at different levels into computational models. This process can be used to investigate complex and collective biological activities that can be described neither by their governing differentiation equations nor by discrete parallel computation. Transparent cluster computing is a convenient and effective method to make time-consuming simulation feasible. Arrhythmias, as a typical case, can be effectively simulated with the methods

[Analysis of the heart sound with arrhythmia based on nonlinear chaos theory].

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Ding, Xiaorong; Guo, Xingming; Zhong, Lisha; Xiao, Shouzhong

2012-10-01

In this paper, a new method based on the nonlinear chaos theory was proposed to study the arrhythmia with the combination of the correlation dimension and largest Lyapunov exponent, through computing and analyzing these two parameters of 30 cases normal heart sound and 30 cases with arrhythmia. The results showed that the two parameters of the heart sounds with arrhythmia were higher than those with the normal, and there was significant difference between these two kinds of heart sounds. That is probably due to the irregularity of the arrhythmia which causes the decrease of predictability, and it's more complex than the normal heart sound. Therefore, the correlation dimension and the largest Lyapunov exponent can be used to analyze the arrhythmia and for its feature extraction.

Calcium-dependent arrhythmias in transgenic mice with heart failure.

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London, Barry; Baker, Linda C; Lee, Joon S; Shusterman, Vladimir; Choi, Bum-Rak; Kubota, Toru; McTiernan, Charles F; Feldman, Arthur M; Salama, Guy

2003-02-01

Transgenic mice overexpressing the inflammatory cytokine tumor necrosis factor (TNF)-alpha (TNF-alpha mice) in the heart develop a progressive heart failure syndrome characterized by biventricular dilatation, decreased ejection fraction, atrial and ventricular arrhythmias on ambulatory telemetry monitoring, and decreased survival compared with nontransgenic littermates. Programmed stimulation in vitro with single extra beats elicits reentrant ventricular arrhythmias in TNF-alpha (n = 12 of 13 hearts) but not in control hearts. We performed optical mapping of voltage and Ca(2+) in isolated perfused ventricles of TNF-alpha mice to study the mechanisms that lead to the initiation and maintenance of the arrhythmias. When compared with controls, hearts from TNF-alpha mice have prolonged of action potential durations (action potential duration at 90% repolarization: 23 +/- 2 ms, n = 7, vs. 18 +/- 1 ms, n = 5; P < 0.05), no increased dispersion of refractoriness between apex and base, elevated diastolic and depressed systolic [Ca(2+)], and prolonged Ca(2+) transients (72 +/- 6 ms, n = 10, vs. 54 +/- 5 ms, n = 8; P < 0.01). Premature beats have diminished action potential amplitudes and conduct in a slow, heterogeneous manner. Lowering extracellular [Ca(2+)] normalizes conduction and prevents inducible arrhythmias. Thus both action potential prolongation and abnormal Ca(2+) handling may contribute to the initiation of reentrant arrhythmias in this heart failure model by mechanisms distinct from enhanced dispersion of refractoriness or triggered activity.

Dobutamine use for arrhythmia induction during electrical programmed heart stimulation

International Nuclear Information System (INIS)

Vanegas, Diego I; Perez, Climaco de J; Montenegro, Juan de J; Orjuela, Alejandro

2006-01-01

isoproterenol is the traditionally used drug for incrementing arrhythmia induction when this induction is not achieved during electric programmed heart stimulation under basal conditions. Dobutamine is an adrenergic agent, chemical precursor of isoproterenol, which can be an alternative for inducing arrhythmia during electrical programmed heart stimulation (PES). Patients and methods: a retrospective comparative study of the experience with dobutamine for inducing arrhythmia during electrical programmed heart stimulation was performed. The following data were collected: number of studies, data about the patient (medical record, age, gender, and study indication) protocol of programmed electrical stimulation, basal and under dobutamine or isoproterenol, and result of the study. Isoproterenol was used in doses of 1 to 3 micrograms per minute until the basal heart rate was incremented at least in 25%. Dobutamine was used in doses of 10 to 40 micrograms per kg of body weight, until obtaining the same increment in the basal heart rate. Results: 1054 electrophysiological studies were evaluated. In 144 patients (group A) isoproterenol was used and in 140, dobutamine (group B). In A group the mean age was 39.2 ± 16.2 and 58.3% were females. In-group B, mean age was 41.9 ± 18.6 and 51% were females. The most frequent symptom was palpitation and the most commonly induced arrhythmia was AV nodal reentry tachycardia in both groups. The induction of arrhythmia during the electrical programmed heat stimulation under drugs was similar in-group A (isoproterenol) respect to group B (dobutamine). Conclusions: There were no statistical significant differences in the induction of arrhythmia during electrical programmed heart stimulation using dobutamine or isoproterenol. Dobutamine may be safe and may be successfully used as an alternative to isoproterenol for arrhythmia induction during electrical programmed stimulation

Increasing Prevalence of Atrial Fibrillation and Permanent Atrial Arrhythmias in Congenital Heart Disease.

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Labombarda, Fabien; Hamilton, Robert; Shohoudi, Azadeh; Aboulhosn, Jamil; Broberg, Craig S; Chaix, Marie A; Cohen, Scott; Cook, Stephen; Dore, Annie; Fernandes, Susan M; Fournier, Anne; Kay, Joseph; Macle, Laurent; Mondésert, Blandine; Mongeon, François-Pierre; Opotowsky, Alexander R; Proietti, Anna; Rivard, Lena; Ting, Jennifer; Thibault, Bernard; Zaidi, Ali; Khairy, Paul

2017-08-15

Atrial arrhythmias are the most common complication encountered in the growing and aging population with congenital heart disease. This study sought to assess the types and patterns of atrial arrhythmias, associated factors, and age-related trends. A multicenter cohort study enrolled 482 patients with congenital heart disease and atrial arrhythmias, age 32.0 ± 18.0 years, 45.2% female, from 12 North American centers. Qualifying arrhythmias were classified by a blinded adjudicating committee. The most common presenting arrhythmia was intra-atrial re-entrant tachycardia (IART) (61.6%), followed by atrial fibrillation (28.8%), and focal atrial tachycardia (9.5%). The proportion of arrhythmias due to IART increased with congenital heart disease complexity from 47.2% to 62.1% to 67.0% in patients with simple, moderate, and complex defects, respectively (p = 0.0013). Atrial fibrillation increased with age to surpass IART as the most common arrhythmia in those ≥50 years of age (51.2% vs. 44.2%; p congenital heart disease, with a predominantly paroxysmal pattern. However, atrial fibrillation increases in prevalence and atrial arrhythmias progressively become permanent as the population ages. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Dual chamber arrhythmia detection in the implantable cardioverter defibrillator.

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Dijkman, B; Wellens, H J

2000-10-01

Dual chamber implantable cardioverter defibrillator (ICD) technology extended ICD therapy to more than termination of hemodynamically unstable ventricular tachyarrhythmias. It created the basis for dual chamber arrhythmia management in which dependable detection is important for treatment and prevention of both ventricular and atrial arrhythmias. Dual chamber detection algorithms were investigated in two Medtronic dual chamber ICDs: the 7250 Jewel AF (33 patients) and the 7271 Gem DR (31 patients). Both ICDs use the same PR Logic algorithm to interpret tachycardia as ventricular tachycardia (VT), supraventricular tachycardia (SVT), or dual (VT+ SVT). The accuracy of dual chamber detection was studied in 310 of 1,367 spontaneously occurring tachycardias in which rate criterion only was not sufficient for arrhythmia diagnosis. In 78 episodes there was a double tachycardia, in 223 episodes SVT was detected in the VT or ventricular fibrillation zone, and in 9 episodes arrhythmia was detected outside the boundaries of the PR Logic functioning. In 100% of double tachycardias the VT was correctly diagnosed and received priority treatment. SVT was seen in 59 (19%) episodes diagnosed as VT. The causes of inappropriate detection were (1) algorithm failure (inability to fulfill the PRarrhythmias. Dual chamber detection algorithms evaluated in a subset of diagnostically difficult arrhythmias allow safe detection of double tachycardias but require further extension and programmability to

Types of Arrhythmia in Children

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... even though they may need to keep taking medicine. Your child will probably need periodic check-ups but will ... minute. Understand and manage medications Parents of a child taking medicine for an arrhythmia should give the medicine at ...

Pharmacogenetics of drug-induced arrhythmias

DEFF Research Database (Denmark)

De Bruin, Marie L; van Puijenbroek, Eugene P; Bracke, Madelon

2006-01-01

PURPOSE: The bottleneck in pharmacogenetic research on rare adverse drug reactions (ADR) is retrieval of patients. Spontaneous reports of ADRs may form a useful source of patients. We investigated the feasibility of a pharmacogenetic study, in which cases were selected from the database...... of a spontaneous reporting system for ADRs, using drug-induced arrhythmias as an example. METHODS: Reports of drug-induced arrhythmias to proarrhythmic drugs were selected from the database of the Netherlands Pharmacovigilance Centre (1996-2003). Information on the patient's general practitioner (GP) was obtained...... be included in the study, giving an overall participation rate of 9% (4/45). The main reason for GPs not being willing to participate was lack of time. Variants were identified in KCNH2, SCN5A and KCNE1. CONCLUSIONS: Spontaneous reporting systems for ADRs may be used for pharmacogenetic research. The methods...

A Proposal for Cardiac Arrhythmia Classification using Complexity Measures

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AROTARITEI, D.

2017-08-01

Full Text Available Cardiovascular diseases are one of the major problems of humanity and therefore one of their component, arrhythmia detection and classification drawn an increased attention worldwide. The presence of randomness in discrete time series, like those arising in electrophysiology, is firmly connected with computational complexity measure. This connection can be used, for instance, in the analysis of RR-intervals of electrocardiographic (ECG signal, coded as binary string, to detect and classify arrhythmia. Our approach uses three algorithms (Lempel-Ziv, Sample Entropy and T-Code to compute the information complexity applied and a classification tree to detect 13 types of arrhythmia with encouraging results. To overcome the computational effort required for complexity calculus, a cloud computing solution with executable code deployment is also proposed.

P wave detector with PP rhythm tracking: evaluation in different arrhythmia contexts

International Nuclear Information System (INIS)

Portet, François

2008-01-01

Automatic detection of atrial activity (P waves) in an electrocardiogram (ECG) is a crucial task to diagnose the presence of arrhythmias. The P wave is difficult to detect and most of the approaches in the literature have been evaluated on normal sinus rhythms and rarely considered arrhythmia contexts other than atrial flutter and fibrillation. A novel knowledge-based P wave detector algorithm is presented. It is self-adaptive to the patient and able to deal with certain arrhythmias by tracking the PP rhythm. The detector has been tested on 12 records of the MIT-BIH arrhythmia database containing several ventricular and supra-ventricular arrhythmias. On the overall records, the detector demonstrates Se = 96.60% and Pr = 95.46%; for the normal sinus rhythm, it reaches Se = 97.76% and Pr = 96.80% and, in the case of Mobitz type II, it demonstrates Se = 72.79% and Pr = 99.51%. It also shows good performance for trigeminy and bigeminy, and outperforms some more sophisticated techniques. Although the results emphasize the difficulty of P wave detection in difficult arrhythmias (supra and ventricular tachycardias), it shows that domain knowledge can efficiently support signal processing techniques

Epidemiology of Arrhythmias in Children

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R Prem Sekar

2008-05-01

Full Text Available Unlike the adult population, arrhythmias occur less commonly in childhood. Only 5% of the emergency hospital admissions in the paediatric population is attributed to symptomatic arrhythmias. Majority of these tend to be accessory pathway mediated supraventricular tachyarrhythmias such as Wolff-Parkinson-White (WPW syndrome, permanent junctional reciprocating tachycardia (PJRT and Mahaim tachycardia. The non accessory pathway mediated supraventricular tachyarrhythmias commonly seen in children are junctional ectopic tachycardia (JET and automatic ectopic atrial tachycardia (AET and occur mostly in the post operative period after intracardiac repair for a structural heart defect. Ventricular tachycardia (VT although uncommon, occurs in the paediatric age group in association with hypertrophic cardiomyopathy (HCM, long QT syndrome (LQTS and Brugada syndrome. Occasionally, VT can also present symptomatically as incessant idiopathic infant ventricular tachycardia, right ventricular outflow tract tachycardia, benign VT, catecholaminic VT, idiopathic left ventricular tachycardia and in post cardiac surgical patients.

Multi-arrhythmias detection with an XML rule-based system from 12-Lead Electrocardiogram.

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Khelassi, Abdeldjalil; Yelles-Chaouche, Sarra-Nassira; Benais, Faiza

2017-05-01

The computer-aided detection of cardiac arrhythmias stills a crucial application in medical technologies. The rule based systems RBS ensure a high level of transparency and interpretability of the obtained results. To facilitate the diagnosis of the cardiologists and to reduce the uncertainty made in this diagnosis. In this research article, we have realized a classification and automatic recognition of cardiac arrhythmias, by using XML rules that represent the cardiologist knowledge. Thirteen experiments with different knowledge bases were realized for improving the performance of the used method in the detection of 13 cardiac arrhythmias. In the first 12 experiments, we have designed a specialized knowledge base for each cardiac arrhythmia, which contains just one arrhythmia detection rule. In the last experiment, we applied the knowledge base which contains rules of 12 arrhythmias. We used, for the experiments, an international data set with 279 features and 452 records characterizing 12 leads of ECG signal and social information of patients. The data sets were constructed and published at Bilkent University of Ankara, Turkey. In addition, the second version of the self-developed software "XMLRULE" was used; the software can infer more than one class and facilitate the interpretability of the obtained results. The 12 first experiments give 82.80% of correct detection as the mean of all experiments, the results were between 19% and 100% with a low rate in just one experiment. The last experiment in which all arrhythmias are considered, the results of correct detection was 38.33% with 90.55% of sensibility and 46.24% of specificity. It was clearly show that in these results the good choice of the classification model is very beneficial in terms of performance. The obtained results were better than the published results with other computational methods for the mono class detection, but it was less in multi-class detection. The RBS is the most transparent method for

Disease and drug-induced arrhythmias : the example of obstructive pulmonary disease

NARCIS (Netherlands)

Warnier, M.J.

2014-01-01

Notwithstanding the clinical importance of cardiac arrhythmias, relevant information about the background risk and the exact underlying mechanisms of cardiac arrhythmias in patients with obstructive pulmonary disease (asthma and chronic obstructive pulmonary disease [COPD]) is still lacking. The

[Catheter ablation in patients with refractory cardiac arrhythmias with radiofrequency techniques].

Science.gov (United States)

de Paola, A A; Balbão, C E; Silva Netto, O; Mendonça, A; Villacorta, H; Vattimo, A C; Souza, I A; Guiguer Júnior, N; Portugal, O P; Martinez Filho, E E

1993-02-01

evaluate the efficacy of radiofrequency catheter ablation in patients with refractory cardiac arrhythmias. twenty patients with refractory cardiac arrhythmias were undertaken to electrophysiologic studies for diagnosis and radiofrequency catheter ablation of their reentrant arrhythmias. Ten patients were men and 10 women with ages varying from 13 to 76 years (mean = 42.4 years). Nineteen patients had supraventricular tachyarrhythmias: One patient had atrial tachycardia and 1 atrial fibrillation with rapid ventricular rate, 5 patients had reentrant nodal tachycardia, 12 patients had reentrant atrioventricular tachycardia and 1 patient had right ventricular outflow tract tachycardia. the mean time of the procedure was 4.1 hours. The radiofrequency current energy applied was 40-50 V for 30-40 seconds. Ablation was successful in 18/20 (90%) patients; in 15/18 (83%) of successfully treated patients the same study was done for diagnosis and radiofrequency ablation. One patient had femoral arterial occlusion and was treated with no significant sequelae. During a mean follow-up of 4 months no preexcitation or reentrant tachycardia occurred. the results of our experience with radiofrequency catheter ablation of cardiac arrhythmias suggest that this technique can benefit an important number of patients with cardiac arrhythmias.

Illicit drugs and cardiac arrhythmias in athletes.

Science.gov (United States)

Furlanello, Francesco; Serdoz, Laura Vitali; Cappato, Riccardo; De Ambroggi, Luigi

2007-08-01

The current management of athletes with cardiac arrhythmias has become complicated by the widespread use of illicit drugs, which can be arrhythmogenic. The World Anti-Doping Agency annually updates a list of prohibited substances and methods banned by the International Olympic Committee that includes different classes of substances namely, anabolic androgenic steroids, hormones and related substances, beta2-agonists, diuretics, stimulants, narcotics, cannabinoids, glucocorticosteroids, alcohol, beta-blockers and others. Almost all illicit drugs may cause, through a direct or indirect arrhythmogenic effect, a wide range of cardiac arrhythmias (focal or reentry type, supraventricular and/or ventricular) that can even be lethal and which are frequently sport activity related. A large use of illicit drugs has been documented in competitive athletes, but the arrhythmogenic effect of specific substances is not precisely known. Precipitation of cardiac arrhythmias, particularly in the presence of a latent electrophysiologic substrate including some inherited cardiomyopathies, at risk of sudden death or due to long-term consumption of the substances, should raise the suspicion that illicit drugs may be a possible cause and lead cardiologists to investigate carefully this relationship and appropriately prevent the clinical consequences.

Gated cardiac blood pool studies in arrhythmias

International Nuclear Information System (INIS)

Itti, R.; Casset, D.; Philippe, L.; Cosnay, P.; Fauchier, J.P.

1988-01-01

Biventricular phase analysis a gated blood pool studies may help to solve two fundamental questions raised by patients suffering from arrhythmias: localization of an electrical cardiac activation abnormality by means of contraction mapping and assesment of an underlying organic disease using the phase histograms and their standard deviations. Three groups of patients have been evaluated to demonstrate the usefulness of radioisotopic techniques in arrhythmias: 36 patients with a Wolff-Parkinson-White syndrom, 27 patients studied during a ventricular tachycardia attack and 32 patients suspected of arrhythmogenic ventricular dysplasia. Correlations with invasive electrophysiologic studies are presented and the diagnostic and therapeutic implications of these results are discussed [fr

Gated cardiac blood pool studies in arrhythmias

Energy Technology Data Exchange (ETDEWEB)

Itti, R.; Casset, D.; Philippe, L.; Cosnay, P.; Fauchier, J.P.

1988-01-01

Biventricular phase analysis a gated blood pool studies may help to solve two fundamental questions raised by patients suffering from arrhythmias: localization of an electrical cardiac activation abnormality by means of contraction mapping and assesment of an underlying organic disease using the phase histograms and their standard deviations. Three groups of patients have been evaluated to demonstrate the usefulness of radioisotopic techniques in arrhythmias: 36 patients with a Wolff-Parkinson-White syndrom, 27 patients studied during a ventricular tachycardia attack and 32 patients suspected of arrhythmogenic ventricular dysplasia. Correlations with invasive electrophysiologic studies are presented and the diagnostic and therapeutic implications of these results are discussed.

Targeting sodium channels in cardiac arrhythmia

NARCIS (Netherlands)

Remme, Carol Ann; Wilde, Arthur A. M.

2014-01-01

Cardiac voltage-gated sodium channels are responsible for proper electrical conduction in the heart. During acquired pathological conditions and inherited sodium channelopathies, altered sodium channel function causes conduction disturbances and ventricular arrhythmias. Although the clinical,

Use of bipolar radiofrequency catheter ablation in treatment of cardiac arrhythmias.

Science.gov (United States)

Soucek, Filip; Starek, Zdenek

2018-05-23

Background Arrhythmia management is a complex process involving both pharmacological and non-pharmacological approaches. Radiofrequency ablation is the pillar of non-pharmacological arrhythmia treatment. Unipolar ablation is considered to be the gold standard in the treatment of the majority of arrhythmias; however, its efficacy is limited to specific cases. In particular, the creation of deep or transmural lesions to eliminate intramurally originating arrhythmias remains inadequate. Bipolar ablation is proposed as an alternative to overcome unipolar ablation boundaries. Results Despite promising results gained from in vitro and animal studies showing that bipolar ablation is superior in creating transmural lesions, the use of bipolar ablation in daily clinical practice is limited. Several studies have been published showing that bipolar ablation is effective in the treatment of clinical arrhythmias after failed unipolar ablation, however there is inconsistency regarding safety of bipolar ablation within the available research papers. According to research evidence the most common indications for bipolar ablation use are ventricular originating rhythmic disorders in patients with structural heart disease resistant to standard radiofrequency ablation. Conclusions To allow wider clinical application the efficiency and safety of bipolar ablation need to be verified in future studies. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Studies of yeast cell oxygenation and energetics by laser fluorometry of reduced nicotinamide adenine dinucleotide

Science.gov (United States)

Pan, Fu-shih; Chen, Stephen; Mintzer, Robert A.; Chen, Chin-Tu; Schumacker, Paul

1991-03-01

It is of fundamental importance for biological scientists to assess cellular energetics. Under aerobic conditions, the tricarboxylic acid cycle (TCA cycle) is coupled with the mitochondrial electron cascade pathway to provide the cell with energy. The nicotinamide adenine dinucleotide-conjugated pair (NAD and NADH) is the coenzyme in numerous important biomedical reactions which include several important dehydrogenase reactions in the TCA cycle. Based on Le Chatelier's principle, NADH will accumulate when this energy production mechanism is impaired. The relative amounts of NAD and NADH in a cell are defined as the redox state of the cell (Williamson et.al. 1967) which provides a valuable index of cellular energetics. The sum of the amounts of NAD and NADH in a cell may be assumed to be constant during a finite time; therefore, a reliable means of measuring the NADH concentration would provide us with a useful indicator of tissue viability. Traditionally, the quantities of NADH and NAD may be measured by chemical assay methods. We can avoid these tediois analyses by exploiting the significant difference between the ultraviolet absorption spectra of this redox pair. However, because of the opacity of biological samples and the interference of other biochemicals that also absorb ultraviolet radiation, measurement of NADH and NAD+ concentrations in vivo by absorption spectroscopy is not feasible.

The association of air temperature with cardiac arrhythmias

Science.gov (United States)

Čulić, Viktor

2017-11-01

The body response to meteorological influences may activate pathophysiological mechanisms facilitating the occurrence of cardiac arrhythmias in susceptible patients. Putative underlying mechanisms include changes in systemic vascular resistance and blood pressure, as well as a network of proinflammatory and procoagulant processes. Such a chain reaction probably occurs within the time window of several hours, so use of daily average values of meteorological elements do not seem appropriate for investigation in this area. In addition, overall synoptic situation, and season-specific combinations of meteorological elements and air pollutant levels probably cause the overall effect rather than a single atmospheric element. Particularly strong interrelations have been described among wind speed, air pressure and temperature, relative air humidity, and suspended particulate matter. This may be the main reason why studies examining the association between temperature and ventricular arrhythmias have found linear positive, negative, J-shaped or no association. Further understanding of the pathophysiological adaptation to atmospheric environment may help in providing recommendations for protective measures during "bad" weather conditions in patients with cardiac arrhythmias.

ECG scaling properties of cardiac arrhythmias using detrended fluctuation analysis

International Nuclear Information System (INIS)

Rodriguez, E; Echeverria, J C; Alvarez-Ramirez, J; Lerma, C

2008-01-01

We applied detrended fluctuation analysis to characterize at very short time scales during episodes of cardiac arrhythmias the raw electrocardiogram (ECG) waveform, aiming to get a global insight into its dynamical behaviour in patients who experienced sudden death. We found that in 15 recordings involving different types of arrhythmias (taken from PhysioNet's Sudden Cardiac Death Holter Database), the ECG waveform, besides showing a less-random dynamics, becomes more regular during bigeminy, ventricular tachycardia or even atrial fibrillation and ventricular fibrillation. The ECG waveform scaling properties thus suggest that reduced complexity dominates the underlying mechanisms of arrhythmias. Among other explanations, this may result from shorted or restricted (i.e. less diverse) pathways of conduction of the electrical activity within ventricles

Cardiac arrhythmias and left ventricular hypertrophy in systemic hypertension

International Nuclear Information System (INIS)

Sultana, R.; Sultana, N.; Rashid, A.; Rasheed, S.Z.; Ahmed, M.; Ishaq, M.; Samad, A.

2010-01-01

Background: Hypertensive left ventricular hypertrophy (LVH) is associated with increased risk of arrhythmias and mortality. Objective was to investigate the prevalence of cardiac arrhythmias and LVH in systemic hypertension. Methods: In all subjects blood pressure was measured, electrocardiography and echocardiography was done. Holter monitoring and exercise test perform in certain cases. There were 500 hypertensive patients, 156 (31.2%) men and 344 (69%) women >30 years of age in the study. Among them 177 (35.4%) were diabetic, 224 (45%) were dyslipidemia, 188 (37.6%) were smokers, and 14 (3%) had homocysteinemia. Mean systolic BP (SBP) was 180 +- 20 mm Hg and diastolic BP (DBP) was 95 +- 12 in male and female patients. Left ventricular mass index (LVMI) was 119.2 +- 30 2 2gm/m in male while 103 +- 22 gm/m in female patients. Palpitation was seen in 126 (25%) male and 299 (59.8%) female patients. Atrial fibrillation was noted in 108 (21.6%) male and 125 (25%) female patients, 30 (6%) male and 82 (16.4%) female patients had atrial flutter. Ventricular tachycardia was noted in 37 (7.4%) male and 59 (11.8%) female patients. Holter monitoring showed significant premature ventricular contractions (PVC'S) in 109 (21.8%) male and 128 (25.69%) female patients while Holter showed atrial arrhythmias (APC'S) in 89 (17.8%) males and 119 (23.8%) females. Angiography findings diagnosed coronary artery disease in 119 (23.8%) with CAD male and 225 (45%) without CAD while 47 (9.4%) females presented with CAD and 109 (21.8%) without CAD. Conclusion: A significant association has been demonstrated between hypertension and arrhythmias. Diastolic dysfunction of the left ventricle, left atrial size and function, as well as LVH have been suggested as the underlying risk factors for supraventricular, ventricular arrhythmias and sudden death in hypertensives with LVH. (author)

Cardiac arrhythmias and left ventricular hypertrophy in systemic hypertension

Energy Technology Data Exchange (ETDEWEB)

Sultana, R; Sultana, N; Rashid, A; Rasheed, S Z; Ahmed, M; Ishaq, M; Samad, A [Karachi Institute of Heart Diseases, Karachi (Pakistan)

2010-10-15

Background: Hypertensive left ventricular hypertrophy (LVH) is associated with increased risk of arrhythmias and mortality. Objective was to investigate the prevalence of cardiac arrhythmias and LVH in systemic hypertension. Methods: In all subjects blood pressure was measured, electrocardiography and echocardiography was done. Holter monitoring and exercise test perform in certain cases. There were 500 hypertensive patients, 156 (31.2%) men and 344 (69%) women >30 years of age in the study. Among them 177 (35.4%) were diabetic, 224 (45%) were dyslipidemia, 188 (37.6%) were smokers, and 14 (3%) had homocysteinemia. Mean systolic BP (SBP) was 180 +- 20 mm Hg and diastolic BP (DBP) was 95 +- 12 in male and female patients. Left ventricular mass index (LVMI) was 119.2 +- 30 2 2gm/m in male while 103 +- 22 gm/m in female patients. Palpitation was seen in 126 (25%) male and 299 (59.8%) female patients. Atrial fibrillation was noted in 108 (21.6%) male and 125 (25%) female patients, 30 (6%) male and 82 (16.4%) female patients had atrial flutter. Ventricular tachycardia was noted in 37 (7.4%) male and 59 (11.8%) female patients. Holter monitoring showed significant premature ventricular contractions (PVC'S) in 109 (21.8%) male and 128 (25.69%) female patients while Holter showed atrial arrhythmias (APC'S) in 89 (17.8%) males and 119 (23.8%) females. Angiography findings diagnosed coronary artery disease in 119 (23.8%) with CAD male and 225 (45%) without CAD while 47 (9.4%) females presented with CAD and 109 (21.8%) without CAD. Conclusion: A significant association has been demonstrated between hypertension and arrhythmias. Diastolic dysfunction of the left ventricle, left atrial size and function, as well as LVH have been suggested as the underlying risk factors for supraventricular, ventricular arrhythmias and sudden death in hypertensives with LVH. (author)

Channelopathies - Emerging Trends in The Management of Inherited Arrhythmias

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Priya Chockalingam, MBBS, MRCPCH, PhD

2015-01-01

Full Text Available In spite of their relative rarity, inheritable arrhythmias have come to the forefront as a group of potentially fatal but preventable cause of sudden cardiac death in children and (young adults. Comprehensive management of inherited arrhythmias includes diagnosing and treating the proband and identifying and protecting affected family members. This has been made possible by the vast advances in the field of molecular biology enabling better understanding of the genetic underpinnings of some of these disease groups, namely congenital long QT syndrome, catecholaminergic polymorphic ventricular tachycardia and Brugada syndrome. The ensuing knowledge of the genotype-phenotype correlations enables us to risk-stratify, prognosticate and treat based on the genetic test results. The various diagnostic modalities currently available to us, including clinical tools and genetic technologies, have to be applied judiciously in order to promptly identify those affected and to spare the emotional burden of a potentially lethal disease in the unaffected individuals. The therapeutic armamentarium of inherited arrhythmias includes pharmacological agents, device therapies and surgical interventions. A treatment strategy keeping in mind the risk profile of the patients, the local availability of drugs and the expertise of the treating personnel is proving effective. While opportunities for research are numerous in this expanding field of medicine, there is also tremendous scope for incorporating the emerging trends in managing patients and families with inherited arrhythmias in the Indian subcontinent.

Effect of different doses of oxytocin on cardiac electrophysiology and arrhythmias induced by ischemia.

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Houshmand, Fariba; Faghihi, Mahdieh; Imani, Alireza; Kheiri, Soleiman

2017-01-01

The onset of acute myocardial ischemia (MI) is accompanied by a rapid increase in electrical instability and often fatal ventricular arrhythmias. This study investigated that whether oxytocin (OT) can modulate ischemia-induced arrhythmias and considered relationships between the severity of arrhythmia and the electrocardiogram parameters during ischemia. OT (0.0001-1 μg) was administrated intraperitoneally 30 min before ischemia. To examine receptor involved, a selective OT-receptor antagonist, atosiban (ATO), was infused 10 min before OT. OT caused a significant and biphasic dose-dependent reduction in ectopic heart activity and arrhythmia score. OT doses that reduced ventricular arrhythmia elicited significant increase in QT interval. OT attenuated the electrophysiological changes associated with MI and there was significant direct relationship between QRS duration and arrhythmia score. ATO treatment reduced beneficial effects of OT on arrhythmogenesis. Nevertheless, ATO failed to alter OT effects on premature ventricular contractions. We assume that the ability of OT to modulate the electrical activity of the heart may play an important role in the antiarrhythmic actions of OT.

Effect of different doses of oxytocin on cardiac electrophysiology and arrhythmias induced by ischemia

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Fariba Houshmand

2017-01-01

Full Text Available The onset of acute myocardial ischemia (MI is accompanied by a rapid increase in electrical instability and often fatal ventricular arrhythmias. This study investigated that whether oxytocin (OT can modulate ischemia-induced arrhythmias and considered relationships between the severity of arrhythmia and the electrocardiogram parameters during ischemia. OT (0.0001–1 μg was administrated intraperitoneally 30 min before ischemia. To examine receptor involved, a selective OT-receptor antagonist, atosiban (ATO, was infused 10 min before OT. OT caused a significant and biphasic dose-dependent reduction in ectopic heart activity and arrhythmia score. OT doses that reduced ventricular arrhythmia elicited significant increase in QT interval. OT attenuated the electrophysiological changes associated with MI and there was significant direct relationship between QRS duration and arrhythmia score. ATO treatment reduced beneficial effects of OT on arrhythmogenesis. Nevertheless, ATO failed to alter OT effects on premature ventricular contractions. We assume that the ability of OT to modulate the electrical activity of the heart may play an important role in the antiarrhythmic actions of OT.

The risk of arrhythmias following coronary artery bypass surgery: do smokers have a paradox effect?

LENUS (Irish Health Repository)

Al-Sarraf, Nael

2010-11-01

Smoking is reported to increase the risk of arrhythmias. However, there are limited data on its effects on arrhythmias following coronary artery bypass graft (CABG). This is a retrospective review of a prospective database of all CABG patients over an eight-year period. Our cohort (n=2813) was subdivided into: current (n=1169), former (n=837), and non-smokers (n=807). Predictors of arrhythmias following CABG in relation to smoking status were analysed. Atrial arrhythmias occurred in 942 patients (33%). Ventricular arrhythmias occurred in 48 patients (2%) and high-grade atrioventricular block occurred in five patients (0.2%). Arrhythmias were lower in current smokers than former and non-smokers (29% vs. 40% vs. 39%, respectively P<0.001). Logistic regression analysis showed 30% arrhythmia risk reduction in smokers compared to non-smokers [odds ratio (OR) 0.7, 95% confidence intervals (CI) 0.5-0.8] and this effect persisted after accounting for potential confounders while former smokers had the same risk as non-smokers (OR 1.04, CI 0.9-1.3). There were no significant differences in mortality. Smokers are less prone to develop arrhythmias following CABG. This paradox effect is lost in former smokers. This effect is possibly due to a lower state of hyper adrenergic stimulation observed in smokers than non-smokers following the stress of surgery.

Carbon monoxide induces cardiac arrhythmia via induction of the late Na+ current.

Science.gov (United States)

Dallas, Mark L; Yang, Zhaokang; Boyle, John P; Boycott, Hannah E; Scragg, Jason L; Milligan, Carol J; Elies, Jacobo; Duke, Adrian; Thireau, Jérôme; Reboul, Cyril; Richard, Sylvain; Bernus, Olivier; Steele, Derek S; Peers, Chris

2012-10-01

Clinical reports describe life-threatening cardiac arrhythmias after environmental exposure to carbon monoxide (CO) or accidental CO poisoning. Numerous case studies describe disruption of repolarization and prolongation of the QT interval, yet the mechanisms underlying CO-induced arrhythmias are unknown. To understand the cellular basis of CO-induced arrhythmias and to identify an effective therapeutic approach. Patch-clamp electrophysiology and confocal Ca(2+) and nitric oxide (NO) imaging in isolated ventricular myocytes was performed together with protein S-nitrosylation to investigate the effects of CO at the cellular and molecular levels, whereas telemetry was used to investigate effects of CO on electrocardiogram recordings in vivo. CO increased the sustained (late) component of the inward Na(+) current, resulting in prolongation of the action potential and the associated intracellular Ca(2+) transient. In more than 50% of myocytes these changes progressed to early after-depolarization-like arrhythmias. CO elevated NO levels in myocytes and caused S-nitrosylation of the Na(+) channel, Na(v)1.5. All proarrhythmic effects of CO were abolished by the NO synthase inhibitor l-NAME, and reversed by ranolazine, an inhibitor of the late Na(+) current. Ranolazine also corrected QT variability and arrhythmias induced by CO in vivo, as monitored by telemetry. Our data indicate that the proarrhythmic effects of CO arise from activation of NO synthase, leading to NO-mediated nitrosylation of Na(V)1.5 and to induction of the late Na(+) current. We also show that the antianginal drug ranolazine can abolish CO-induced early after-depolarizations, highlighting a novel approach to the treatment of CO-induced arrhythmias.

High-throughput cardiac safety evaluation and multi-parameter arrhythmia profiling of cardiomyocytes using microelectrode arrays

Energy Technology Data Exchange (ETDEWEB)

Gilchrist, Kristin H., E-mail: kgilchrist@rti.org; Lewis, Gregory F.; Gay, Elaine A.; Sellgren, Katelyn L.; Grego, Sonia

2015-10-15

Microelectrode arrays (MEAs) recording extracellular field potentials of human-induced pluripotent stem cell-derived cardiomyocytes (hiPS-CM) provide a rich data set for functional assessment of drug response. The aim of this work is the development of a method for a systematic analysis of arrhythmia using MEAs, with emphasis on the development of six parameters accounting for different types of cardiomyocyte signal irregularities. We describe a software approach to carry out such analysis automatically including generation of a heat map that enables quick visualization of arrhythmic liability of compounds. We also implemented signal processing techniques for reliable extraction of the repolarization peak for field potential duration (FPD) measurement even from recordings with low signal to noise ratios. We measured hiPS-CM's on a 48 well MEA system with 5 minute recordings at multiple time points (0.5, 1, 2 and 4 h) after drug exposure. We evaluated concentration responses for seven compounds with a combination of hERG, QT and clinical proarrhythmia properties: Verapamil, Ranolazine, Flecainide, Amiodarone, Ouabain, Cisapride, and Terfenadine. The predictive utility of MEA parameters as surrogates of these clinical effects were examined. The beat rate and FPD results exhibited good correlations with previous MEA studies in stem cell derived cardiomyocytes and clinical data. The six-parameter arrhythmia assessment exhibited excellent predictive agreement with the known arrhythmogenic potential of the tested compounds, and holds promise as a new method to predict arrhythmic liability. - Highlights: • Six parameters describing arrhythmia were defined and measured for known compounds. • Software for efficient parameter extraction from large MEA data sets was developed. • The proposed cellular parameter set is predictive of clinical drug proarrhythmia.

Ventricular arrhythmias in the absence of structural heart disease.

Science.gov (United States)

Prystowsky, Eric N; Padanilam, Benzy J; Joshi, Sandeep; Fogel, Richard I

2012-05-15

Ventricular arrhythmia (VA) in structurally normal hearts can be broadly considered under non-life-threatening monomorphic and life-threatening polymorphic rhythms. Monomorphic VA is classified on the basis of site of origin in the heart, and the most common areas are the ventricular outflow tracts and left ventricular fascicles. The morphology of the QRS complexes on electrocardiogram is an excellent tool to identify the site of origin of the rhythm. Although these arrhythmias are common and generally carry an excellent prognosis, rare sudden death events have been reported. Very frequent ventricular ectopy may also result in a cardiomyopathy in a minority of patients. Suppression of VA may be achieved using calcium-channel blockers, beta-adrenergic blockers, and class I or III antiarrhythmic drugs. Radiofrequency ablation has emerged as an excellent option to eliminate these arrhythmias, although certain foci including aortic cusps and epicardium may be technically challenging. Polymorphic ventricular tachycardia (VT) is rare and generally occurs in patients with genetic ion channel disorders including long QT syndrome, Brugada syndrome, catecholaminergic polymorphic VT, and short QT syndrome. Unlike monomorphic VT, these arrhythmic syndromes are associated with sudden death. While the cardiac gross morphology is normal, suggesting a structurally normal heart, abnormalities exist at the molecular level and predispose them to arrhythmias. Another fascinating area, idiopathic ventricular fibrillation and early repolarization syndrome, are undergoing research for a genetic basis. Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

The predictive value of CHADS₂ risk score in post myocardial infarction arrhythmias - a Cardiac Arrhythmias and RIsk Stratification after Myocardial infArction (CARISMA) substudy

DEFF Research Database (Denmark)

Ruwald, Anne-Christine Huth; Gang, Uffe; Thomsen, Poul Erik Bloch

2014-01-01

BACKGROUND: Previous studies have shown substantially increased risk of cardiac arrhythmias and sudden cardiac death in post-myocardial infarction (MI) patients. However it remains difficult to identify the patients who are at highest risk of arrhythmias in the post-MI setting. The purpose...... of this study was to investigate if CHADS₂ score (congestive heart failure, hypertension, age ≥75 years, diabetes and previous stroke/TCI [doubled]) can be used as a risk tool for predicting cardiac arrhythmias after MI. METHODS: The study included 297 post-MI patients from the CARISMA study with left....... Patients were stratified according to CHADS₂ score at enrollment. Congestive heart failure was defined as LVEF ≤40% and NYHA class II, III or IV. RESULTS: We found significantly increased risk of an arrhythmic event with increasing CHADS₂ score (CHADS₂ score=1-2: HR=2.1 [1.1-3.9], p=0.021, CHADS₂ score ≥ 3...

Importance of the atrial channel for ventricular arrhythmia therapy in the dual chamber implantable cardioverter defibrillator.

Science.gov (United States)

Dijkman, B; Wellens, H J

2000-12-01

Performance of dual chamber implantable cardioverter defibrillator (ICD) systems has been judged based on functioning of the ventricular tachycardia:supraventricular tachycardia (VT:SVT) discrimination criteria and DDD pacing. The purpose of this study was to evaluate the use of dual chamber diagnostics to improve the electrical and antiarrhythmic therapy of ventricular arrhythmias. Information about atrial and ventricular rhythm in relation to ventricular arrhythmia occurrence and therapy was evaluated in 724 spontaneous arrhythmia episodes detected and treated by three types of dual chamber ICDs in 41 patients with structural heart disease. Device programming was based on clinically documented and induced ventricular arrhythmias. In ambulatory patients, sinus tachycardia preceded ventricular arrhythmias more often than in the hospital during exercise testing. The incidence of these VTs could be reduced by increasing the dose of a beta-blocking agent in only two patients. In five patients in whom sinus tachycardia developed after onset of hemodynamic stable VT, propranolol was more effective than Class III antiarrhythmics combined with another beta-blocking agent with regard to the incidence of VT and pace termination. In all but three cases, atrial arrhythmias were present for a longer time before the onset of ventricular arrhythmias. During atrial arrhythmias, fast ventricular rates before the onset of ventricular rate were observed more often than RR irregularities and short-long RR sequences. Dual chamber diagnostics allowed proper interpretation of detection and therapy outcome in patients with different types of ventricular arrhythmia. The advantages of the dual chamber ICD system go further than avoiding the shortcomings of the single chamber system. Information from the atrial chamber allows better device programming and individualization of drug therapy for ventricular arrhythmia.

Patient characteristics associated with false arrhythmia alarms in intensive care

Directory of Open Access Journals (Sweden)

Harris PR

2017-04-01

Full Text Available Patricia R Harris,1,2 Jessica K Zègre-Hemsey,3,4 Daniel Schindler,5 Yong Bai,6 Michele M Pelter,2,7 Xiao Hu2,8 1Department of Nursing, School of Health and Natural Sciences, Dominican University of California, San Rafael, 2Department of Physiological Nursing, School of Nursing, University of California, San Francisco, CA, 3School of Nursing, 4Department of Emergency Medicine, School of Medicine, University of North Carolina at Chapel Hill, NC, 5Intensive Care Unit, The Neuroscience Center, Sutter Eden Medical Center, Castro Valley, 6Hu Research Laboratory, Department of Physiological Nursing, School of Nursing, University of California, San Francisco, 7ECG Monitoring Research Lab, Department of Physiological Nursing, School of Nursing, 8Physiological Nursing and Neurological Surgery, Affiliate Faculty of Institute for Computational Health Sciences Core Faculty UCB/UCSF Joint Bio-Engineering Graduate Program, University of California, San Francisco, CA, USA Introduction: A high rate of false arrhythmia alarms in the intensive care unit (ICU leads to alarm fatigue, the condition of desensitization and potentially inappropriate silencing of alarms due to frequent invalid and nonactionable alarms, often referred to as false alarms. Objective: The aim of this study was to identify patient characteristics, such as gender, age, body mass index, and diagnosis associated with frequent false arrhythmia alarms in the ICU. Methods: This descriptive, observational study prospectively enrolled patients who were consecutively admitted to one of five adult ICUs (77 beds at an urban medical center over a period of 31 days in 2013. All monitor alarms and continuous waveforms were stored on a secure server. Nurse scientists with expertise in cardiac monitoring used a standardized protocol to annotate six clinically important types of arrhythmia alarms (asystole, pause, ventricular fibrillation, ventricular tachycardia, accelerated ventricular rhythm, and

Risk of arrhythmia induced by psychotropic medications

DEFF Research Database (Denmark)

Fanoe, Søren; Kristensen, Diana; Fink-Jensen, Anders

2014-01-01

with psychotropic medications. The algorithm integrates the risk categories of the individual drugs and pre-disposing risk factors and suggests a prudent follow-up for patients with an increased risk. We believe this clinically manageable guideline might improve safety in the many and rapidly increasing number...... of the major mental disorders are associated with a large risk of suicide if untreated. The observed risk of malignant arrhythmia associated with treatment with psychotropic drugs calls for clinical guidelines integrating the risk of the individual drug and other potentially interacting risk factors......Several drugs used in the treatment of mental diseases are associated with an increased risk of sudden cardiac death (SCD). A general cause-relationship between the intake of these drugs and SCD is unattainable, but numerous case reports of drug-induced malignant arrhythmia and epidemiological...

Effect of Cardiac Arrhythmia Simulation on Nursing Students' Knowledge Acquisition and Retention.

Science.gov (United States)

Tubaishat, Ahmad; Tawalbeh, Loai I

2015-09-01

The realistic and practical environment that simulation provides is an extremely useful part of the teaching process. Simulation is widely used in health and nursing education today. This study aims to evaluate the effect of simulation-based teaching on the acquisition and retention of arrhythmia-related knowledge among nursing students. A randomized controlled design involving a pretest-posttest was used. Nursing students were allocated randomly either to the experimental group (n = 47), who attended simulation scenarios on cardiac arrhythmia, or to the control group (n = 44) who received a traditional lecture on the same topic. A paired t test showed that the mean knowledge score at the posttest was significantly higher than at the pretest for both groups. However, participants in the experimental group demonstrated significantly increased knowledge of cardiac arrhythmia in the first and the second posttest compared with those in the control group. Thus, simulation is superior and significantly improves students' arrhythmia knowledge. © The Author(s) 2014.

Interactions between pacing and arrhythmia detection algorithms in the dual chamber implantable cardioverter defibrillator.

Science.gov (United States)

Dijkman, B; Wellens, H J

2001-09-01

Dual chamber implantable cardioverter defibrillator (ICD) combines the possibility to detect and treat ventricular and atrial arrhythmias with the possibility of modern heart stimulation techniques. Advanced pacing algorithms together with extended arrhythmia detection capabilities can give rise to new types of device-device interactions. Some of the possible interactions are illustrated by four cases documented in four models of dual chamber ICDs. Functioning of new features in dual chamber devices is influenced by the fact that the pacemaker is not a separate device but a part of the ICD system and that both are being used in a patient with arrhythmia. Programming measures are suggested to optimize use of new pacing algorithms while maintaining correct arrhythmia detection.

Risk of Ventricular Arrhythmia with Citalopram and Escitalopram: A Population-Based Study.

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Elena Qirjazi

Full Text Available The risk of ventricular arrhythmia with citalopram and escitalopram is controversial. In this study we investigated the association between these two drugs and the risk of ventricular arrhythmia.We conducted a population-based retrospective cohort study of older adults (mean age 76 years from 2002 to 2012 in Ontario, Canada, newly prescribed citalopram (n = 137 701 or escitalopram (n = 38 436, compared to those prescribed referent antidepressants sertraline or paroxetine (n = 96 620. After inverse probability of treatment weighting using a propensity score, the baseline characteristics of the comparison groups were similar. The primary outcome was a hospital encounter with ventricular arrhythmia within 90 days of a new prescription, assessed using hospital diagnostic codes. The secondary outcome was all-cause mortality within 90 days.Citalopram was associated with a higher risk of a hospital encounter with ventricular arrhythmia compared with referent antidepressants (0.06% vs. 0.04%, relative risk [RR] 1.53, 95% confidence intervals [CI]1.03 to 2.29, and a higher risk of mortality (3.49% vs. 3.12%, RR 1.12, 95% CI 1.06 to 1.18. Escitalopram was not associated with a higher risk of ventricular arrhythmia compared with the referent antidepressants (0.03% vs. 0.04%, RR 0.84, 95% CI 0.42 to 1.68, but was associated with a higher risk of mortality (2.86% vs. 2.63%, RR 1.09, 95% CI 1.01 to 1.18.Among older adults, initiation of citalopram compared to two referent antidepressants was associated with a small but statistically significant increase in the 90-day risk of a hospital encounter for ventricular arrhythmia.

Risk of Ventricular Arrhythmia with Citalopram and Escitalopram: A Population-Based Study.

Science.gov (United States)

Qirjazi, Elena; McArthur, Eric; Nash, Danielle M; Dixon, Stephanie N; Weir, Matthew A; Vasudev, Akshya; Jandoc, Racquel; Gula, Lorne J; Oliver, Matthew J; Wald, Ron; Garg, Amit X

2016-01-01

The risk of ventricular arrhythmia with citalopram and escitalopram is controversial. In this study we investigated the association between these two drugs and the risk of ventricular arrhythmia. We conducted a population-based retrospective cohort study of older adults (mean age 76 years) from 2002 to 2012 in Ontario, Canada, newly prescribed citalopram (n = 137 701) or escitalopram (n = 38 436), compared to those prescribed referent antidepressants sertraline or paroxetine (n = 96 620). After inverse probability of treatment weighting using a propensity score, the baseline characteristics of the comparison groups were similar. The primary outcome was a hospital encounter with ventricular arrhythmia within 90 days of a new prescription, assessed using hospital diagnostic codes. The secondary outcome was all-cause mortality within 90 days. Citalopram was associated with a higher risk of a hospital encounter with ventricular arrhythmia compared with referent antidepressants (0.06% vs. 0.04%, relative risk [RR] 1.53, 95% confidence intervals [CI]1.03 to 2.29), and a higher risk of mortality (3.49% vs. 3.12%, RR 1.12, 95% CI 1.06 to 1.18). Escitalopram was not associated with a higher risk of ventricular arrhythmia compared with the referent antidepressants (0.03% vs. 0.04%, RR 0.84, 95% CI 0.42 to 1.68), but was associated with a higher risk of mortality (2.86% vs. 2.63%, RR 1.09, 95% CI 1.01 to 1.18). Among older adults, initiation of citalopram compared to two referent antidepressants was associated with a small but statistically significant increase in the 90-day risk of a hospital encounter for ventricular arrhythmia.

Cardiac Arrhythmia Classification by Multi-Layer Perceptron and Convolution Neural Networks

Directory of Open Access Journals (Sweden)

Shalin Savalia

2018-05-01

Full Text Available The electrocardiogram (ECG plays an imperative role in the medical field, as it records heart signal over time and is used to discover numerous cardiovascular diseases. If a documented ECG signal has a certain irregularity in its predefined features, this is called arrhythmia, the types of which include tachycardia, bradycardia, supraventricular arrhythmias, and ventricular, etc. This has encouraged us to do research that consists of distinguishing between several arrhythmias by using deep neural network algorithms such as multi-layer perceptron (MLP and convolution neural network (CNN. The TensorFlow library that was established by Google for deep learning and machine learning is used in python to acquire the algorithms proposed here. The ECG databases accessible at PhysioBank.com and kaggle.com were used for training, testing, and validation of the MLP and CNN algorithms. The proposed algorithm consists of four hidden layers with weights, biases in MLP, and four-layer convolution neural networks which map ECG samples to the different classes of arrhythmia. The accuracy of the algorithm surpasses the performance of the current algorithms that have been developed by other cardiologists in both sensitivity and precision.

Cardiac Arrhythmia Classification by Multi-Layer Perceptron and Convolution Neural Networks.

Science.gov (United States)

Savalia, Shalin; Emamian, Vahid

2018-05-04

The electrocardiogram (ECG) plays an imperative role in the medical field, as it records heart signal over time and is used to discover numerous cardiovascular diseases. If a documented ECG signal has a certain irregularity in its predefined features, this is called arrhythmia, the types of which include tachycardia, bradycardia, supraventricular arrhythmias, and ventricular, etc. This has encouraged us to do research that consists of distinguishing between several arrhythmias by using deep neural network algorithms such as multi-layer perceptron (MLP) and convolution neural network (CNN). The TensorFlow library that was established by Google for deep learning and machine learning is used in python to acquire the algorithms proposed here. The ECG databases accessible at PhysioBank.com and kaggle.com were used for training, testing, and validation of the MLP and CNN algorithms. The proposed algorithm consists of four hidden layers with weights, biases in MLP, and four-layer convolution neural networks which map ECG samples to the different classes of arrhythmia. The accuracy of the algorithm surpasses the performance of the current algorithms that have been developed by other cardiologists in both sensitivity and precision.

Carbon monoxide exposure enhances arrhythmia after cardiac stress: involvement of oxidative stress.

Science.gov (United States)

André, Lucas; Gouzi, Fares; Thireau, Jérôme; Meyer, Gregory; Boissiere, Julien; Delage, Martine; Abdellaoui, Aldja; Feillet-Coudray, Christine; Fouret, Gilles; Cristol, Jean-Paul; Lacampagne, Alain; Obert, Philippe; Reboul, Cyril; Fauconnier, Jérémy; Hayot, Maurice; Richard, Sylvain; Cazorla, Olivier

2011-11-01

Arrhythmias following cardiac stress are a key predictor of death in healthy population. Carbon monoxide (CO) is a ubiquitous pollutant promoting oxidative stress and associated with hospitalization for cardiovascular disease and cardiac mortality. We investigated the effect of chronic CO exposure on the occurrence of arrhythmic events after a cardiac stress test and the possible involvement of related oxidative stress. Wistar rats exposed chronically (4 weeks) to sustained urban CO pollution presented more arrhythmic events than controls during recovery after cardiac challenge with isoprenaline in vivo. Sudden death occurred in 22% of CO-exposed rats versus 0% for controls. Malondialdehyde (MDA), an end-product of lipid peroxidation, was increased in left ventricular tissue of CO-exposed rats. Cardiomyocytes isolated from CO-exposed rats showed higher reactive oxygen species (ROS) production (measured with MitoSox Red dye), higher diastolic Ca(2+) resulting from SR calcium leak and an higher occurrence of irregular Ca(2+) transients (measured with Indo-1) in comparison to control cells after a high pacing sequence. Acute treatment with a ROS scavenger (N-acetylcysteine, 20 mmol/L, 1 h) prevented this sequence of alterations and decreased the number of arrhythmic cells following high pacing. Chronic CO exposure promotes oxidative stress that alters Ca(2+) homeostasis (through RYR2 and SERCA defects) and thereby mediates the triggering of ventricular arrhythmia after cardiac stress that can lead to sudden death.

High level of oxygen treatment causes cardiotoxicity with arrhythmias and redox modulation

Energy Technology Data Exchange (ETDEWEB)

Chapalamadugu, Kalyan C.; Panguluri, Siva K. [Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL (United States); Bennett, Eric S. [Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL (United States); Kolliputi, Narasaiah [Division of Allergy and Immunology, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL (United States); Tipparaju, Srinivas M., E-mail: stippara@health.usf.edu [Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL (United States)

2015-01-01

Hyperoxia exposure in mice leads to cardiac hypertrophy and voltage-gated potassium (Kv) channel remodeling. Because redox balance of pyridine nucleotides affects Kv function and hyperoxia alters cellular redox potential, we hypothesized that hyperoxia exposure leads to cardiac ion channel disturbances and redox changes resulting in arrhythmias. In the present study, we investigated the electrical changes and redox abnormalities caused by 72 h hyperoxia treatment in mice. Cardiac repolarization changes were assessed by acquiring electrocardiogram (ECG) and cardiac action potentials (AP). Biochemical assays were employed to identify the pyridine nucleotide changes, Kv1.5 expression and myocardial injury. Hyperoxia treatment caused marked bradycardia, arrhythmia and significantly prolonged (ms) the, RR (186.2 ± 10.7 vs. 146.4 ± 6.2), PR (46.8 ± 3.1 vs. 39.3 ± 1.6), QRS (10.8 ± 0.6 vs. 8.5 ± 0.2), QTc (57.1 ± 3.5 vs. 40 ± 1.4) and JT (13.4 ± 2.1 vs. 7.0 ± 0.5) intervals, when compared with normoxia group. Hyperoxia treatment also induced significant increase in cardiac action potential duration (APD) (ex-APD{sub 90}; 73.8 ± 9.5 vs. 50.9 ± 3.1 ms) and elevated levels of serum markers of myocardial injury; cardiac troponin I (TnI) and lactate dehydrogenase (LDH). Hyperoxia exposure altered cardiac levels of mRNA/protein expression of; Kv1.5, Kvβ subunits and SiRT1, and increased ratios of reduced pyridine nucleotides (NADH/NAD and NADPH/NADP). Inhibition of SiRT1 in H9C2 cells using Splitomicin resulted in decreased SiRT1 and Kv1.5 expression, suggesting that SiRT1 may mediate Kv1.5 downregulation. In conclusion, the cardiotoxic effects of hyperoxia exposure involve ion channel disturbances and redox changes resulting in arrhythmias. - Highlights: • Hyperoxia treatment leads to arrhythmia with prolonged QTc and action potential duration. • Hyperoxia treatment alters cardiac pyridine nucleotide [NAD(P)H/NAD(P)] levels. • SiRT1 and Kv1.5 are co

High level of oxygen treatment causes cardiotoxicity with arrhythmias and redox modulation

International Nuclear Information System (INIS)

Chapalamadugu, Kalyan C.; Panguluri, Siva K.; Bennett, Eric S.; Kolliputi, Narasaiah; Tipparaju, Srinivas M.

2015-01-01

Hyperoxia exposure in mice leads to cardiac hypertrophy and voltage-gated potassium (Kv) channel remodeling. Because redox balance of pyridine nucleotides affects Kv function and hyperoxia alters cellular redox potential, we hypothesized that hyperoxia exposure leads to cardiac ion channel disturbances and redox changes resulting in arrhythmias. In the present study, we investigated the electrical changes and redox abnormalities caused by 72 h hyperoxia treatment in mice. Cardiac repolarization changes were assessed by acquiring electrocardiogram (ECG) and cardiac action potentials (AP). Biochemical assays were employed to identify the pyridine nucleotide changes, Kv1.5 expression and myocardial injury. Hyperoxia treatment caused marked bradycardia, arrhythmia and significantly prolonged (ms) the, RR (186.2 ± 10.7 vs. 146.4 ± 6.2), PR (46.8 ± 3.1 vs. 39.3 ± 1.6), QRS (10.8 ± 0.6 vs. 8.5 ± 0.2), QTc (57.1 ± 3.5 vs. 40 ± 1.4) and JT (13.4 ± 2.1 vs. 7.0 ± 0.5) intervals, when compared with normoxia group. Hyperoxia treatment also induced significant increase in cardiac action potential duration (APD) (ex-APD 90 ; 73.8 ± 9.5 vs. 50.9 ± 3.1 ms) and elevated levels of serum markers of myocardial injury; cardiac troponin I (TnI) and lactate dehydrogenase (LDH). Hyperoxia exposure altered cardiac levels of mRNA/protein expression of; Kv1.5, Kvβ subunits and SiRT1, and increased ratios of reduced pyridine nucleotides (NADH/NAD and NADPH/NADP). Inhibition of SiRT1 in H9C2 cells using Splitomicin resulted in decreased SiRT1 and Kv1.5 expression, suggesting that SiRT1 may mediate Kv1.5 downregulation. In conclusion, the cardiotoxic effects of hyperoxia exposure involve ion channel disturbances and redox changes resulting in arrhythmias. - Highlights: • Hyperoxia treatment leads to arrhythmia with prolonged QTc and action potential duration. • Hyperoxia treatment alters cardiac pyridine nucleotide [NAD(P)H/NAD(P)] levels. • SiRT1 and Kv1.5 are co-regulated in

Hypertension and Cardiac Arrhythmias

DEFF Research Database (Denmark)

Lip, Gregory Y H; Coca, Antonio; Kahan, Thomas

2017-01-01

Hypertension (HTN) is a common cardiovascular risk factor leading to heart failure (HF), coronary artery disease (CAD), stroke, peripheral artery disease and chronic renal failure. Hypertensive heart disease can manifest as many types of cardiac arrhythmias, most commonly being atrial fibrillation......) Council on Hypertension convened a Task Force, with representation from the Heart Rhythm Society (HRS), Asia-Pacific Heart Rhythm Society (APHRS), and Sociedad Latinoamericana de Estimulación Cardíaca y Electrofisiología (SOLEACE), with the remit of comprehensively reviewing the available evidence...

Exercising arrhythmias and sudden cardiac death in horses: Review of the literature and comparative aspects.

Science.gov (United States)

Navas de Solis, C

2016-07-01

Arrhythmias are common in equine athletes during and immediately after exercise. Many of these rhythm variations are not clinically relevant. In horses, a link between different exercising arrhythmias and poor performance or between exercising arrhythmias and sudden cardiac death (SCD) is strongly suspected but not fully understood or proven. SCD during races or competitions is rare, but has catastrophic consequences for the safety of the human partner and public perceptions of welfare during equestrian sports. This review summarises current knowledge of equine exercise arrhythmias and their implications in SCD and compares existing principles and recommendations for equine subjects with those for human athletes. © 2016 EVJ Ltd.

Thyroid hormones and cardiac arrhythmias

Czech Academy of Sciences Publication Activity Database

Tribulová, N.; Knezl, V.; Shainberg, A.; Seki, S.; Soukup, Tomáš

2010-01-01

Roč. 52, 3-4 (2010), s. 102-112 ISSN 1537-1891 R&D Projects: GA ČR(CZ) GA304/08/0256 Grant - others:VEGA(SK) 2/0049/09; APVV(SK) 51-059505; APVV(SK) 51-017905 Institutional research plan: CEZ:AV0Z50110509 Keywords : thyroid hormone * arrhythmias * ion channels * connexin-43 Subject RIV: FA - Cardiovascular Disease s incl. Cardiotharic Surgery Impact factor: 2.174, year: 2010

Quantitative Assessment of Arrhythmia Using Non-linear Approach: A Non-invasive Prognostic Tool

Science.gov (United States)

Chakraborty, Monisha; Ghosh, Dipak

2018-04-01

Accurate prognostic tool to identify severity of Arrhythmia is yet to be investigated, owing to the complexity of the ECG signal. In this paper, we have shown that quantitative assessment of Arrhythmia is possible using non-linear technique based on "Hurst Rescaled Range Analysis". Although the concept of applying "non-linearity" for studying various cardiac dysfunctions is not entirely new, the novel objective of this paper is to identify the severity of the disease, monitoring of different medicine and their dose, and also to assess the efficiency of different medicine. The approach presented in this work is simple which in turn will help doctors in efficient disease management. In this work, Arrhythmia ECG time series are collected from MIT-BIH database. Normal ECG time series are acquired using POLYPARA system. Both time series are analyzed in thelight of non-linear approach following the method "Rescaled Range Analysis". The quantitative parameter, "Fractal Dimension" (D) is obtained from both types of time series. The major finding is that Arrhythmia ECG poses lower values of D as compared to normal. Further, this information can be used to access the severity of Arrhythmia quantitatively, which is a new direction of prognosis as well as adequate software may be developed for the use of medical practice.

Inhibition of Rac1 reduces store overload-induced calcium release and protects against ventricular arrhythmia.

Science.gov (United States)

Zhang, Lili; Lu, Xiangru; Gui, Le; Wu, Yan; Sims, Stephen M; Wang, Guoping; Feng, Qingping

2016-08-01

Rac1 is a small GTPase and plays key roles in multiple cellular processes including the production of reactive oxygen species (ROS). However, whether Rac1 activation during myocardial ischaemia and reperfusion (I/R) contributes to arrhythmogenesis is not fully understood. We aimed to study the effects of Rac1 inhibition on store overload-induced Ca(2+) release (SOICR) and ventricular arrhythmia during myocardial I/R. Adult Rac1(f/f) and cardiac-specific Rac1 knockdown (Rac1(ckd) ) mice were subjected to myocardial I/R and their electrocardiograms (ECGs) were monitored for ventricular arrhythmia. Myocardial Rac1 activity was increased and ventricular arrhythmia was induced during I/R in Rac1(f/f) mice. Remarkably, I/R-induced ventricular arrhythmia was significantly decreased in Rac1(ckd) compared to Rac1(f/f) mice. Furthermore, treatment with Rac1 inhibitor NSC23766 decreased I/R-induced ventricular arrhythmia. Ca(2+) imaging analysis showed that in response to a 6 mM external Ca(2+) concentration challenge, SOICR was induced with characteristic spontaneous intracellular Ca(2+) waves in Rac1(f/f) cardiomyocytes. Notably, SOICR was diminished by pharmacological and genetic inhibition of Rac1 in adult cardiomyocytes. Moreover, I/R-induced ROS production and ryanodine receptor 2 (RyR2) oxidation were significantly inhibited in the myocardium of Rac1(ckd) mice. We conclude that Rac1 activation induces ventricular arrhythmia during myocardial I/R. Inhibition of Rac1 suppresses SOICR and protects against ventricular arrhythmia. Blockade of Rac1 activation may represent a new paradigm for the treatment of cardiac arrhythmia in ischaemic heart disease. © 2016 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

Alternative Energetics DC Microgrid With Hydrogen Energy Storage System

Directory of Open Access Journals (Sweden)

Zaļeskis Genadijs

2016-12-01

Full Text Available This paper is related to an alternative energetics microgrid with a wind generator and a hydrogen energy storage system. The main aim of this research is the development of solutions for effective use of the wind generators in alternative energetics devices, at the same time providing uninterrupted power supply of the critical loads. In this research, it was accepted that the alternative energetics microgrid operates in an autonomous mode and the connection to the conventional power grid is not used. In the case when wind speed is low, the necessary power is provided by the energy storage system, which includes a fuel cell and a tank with stored hydrogen. The theoretical analysis of the storage system operation is made. The possible usage time of the stored hydrogen depends on the available amount of hydrogen and the consumption of the hydrogen by the fuel cell. The consumption, in turn, depends on used fuel cell power. The experimental results suggest that if the wind generator can provide only a part of the needed power, the abiding power can be provided by the fuel cell. In this case, a load filter is necessary to decrease the fuel cell current pulsations.

Immediate postoperative digitalization in the prophylaxis of supraventricular arrhythmias following coronary artery bypass.

Science.gov (United States)

Csicsko, J F; Schatzlein, M H; King, R D

1981-03-01

Regimens of acute preoperative digitalization have been evaluated previously in the prophylaxis of supraventricular tachycardias (SVT) following coronary artery bypass operations, with equivocal results. This study assesses the effectiveness of immediate postoperative digitalization on the incidence of arrhythmias in 407 consecutive patients recovering from myocardial revascularization. In 137 patients treated by our regimen, which begins digitalization within 4 hours postoperatively, the incidence of supraventricular tachyarrhythmias was 2%, while the corresponding figure for 270 untreated patients was 15%. Digitalization reduced the incidence of supraventricular arrhythmias significantly (p less than 0.01), whereas death, ventricular ectopy, and infarction rates were similar in the two groups. The few patients who did have supraventricular arrhythmias while receiving prophylactic digoxin were no more easily treated than patients in the undigitalized group. The timing of administration of digoxin for SVT prophylaxis may be more important than previously recognized. Immediately postoperative digitalization, theoretically preferable to preoperative regimens, is a safe, effective way to reduce the incidence of supraventricular arrhythmias following myocardial revascularization.

Long-term neurodevelopmental outcome after fetal arrhythmia

NARCIS (Netherlands)

Lopriore, Enrico; Aziz, Muhammed I.; Nagel, Helene T.; Blom, Nico A.; Rozendaal, Lieke; Kanhai, Humphrey H. H.; Vandenbussche, Frank P. H. A.

2009-01-01

OBJECTIVE: The purpose of this study was to determine the long-term neurodevelopmental outcome in fetuses with severe tachy- or bradyarrhythmia. STUDY DESIGN: This was a follow-up study to assess the neurologic, mental, and psychomotor development in cases with fetal cardiac arrhythmia. RESULTS: A

Relationship between Fibrosis and Ventricular Arrhythmias in Chagas Heart Disease Without Ventricular Dysfunction

Energy Technology Data Exchange (ETDEWEB)

Tassi, Eduardo Marinho, E-mail: etassi@ibest.com.br [Instituto de Cardiologia Edson Saad - Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil); Continentino, Marcelo Abramoff [Hospital Frei Galvão, Guaratinguetá, SP (Brazil); Nascimento, Emília Matos do; Pereira, Basílio de Bragança [Instituto de Cardiologia Edson Saad - Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil); Coppe - Instituto Alberto Luiz Coimbra de Pós-Graduação e Pesquisa de Engenharia - UFRJ, Rio de Janeiro, RJ (Brazil); Pedrosa, Roberto Coury [Instituto de Cardiologia Edson Saad - Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)

2014-05-15

Patients with Chagas disease and segmental wall motion abnormality (SWMA) have worse prognosis independent of left ventricular ejection fraction (LVEF). Cardiac magnetic resonance (CMR) is currently the best method to detect SWMA and to assess fibrosis. To quantify fibrosis by using late gadolinium enhancement CMR in patients with Chagas disease and preserved or minimally impaired ventricular function (> 45%), and to detect patterns of dependence between fibrosis, SWMA and LVEF in the presence of ventricular arrhythmia. Electrocardiogram, treadmill exercise test, Holter and CMR were carried out in 61 patients, who were divided into three groups as follows: (1) normal electrocardiogram and CMR without SWMA; (2) abnormal electrocardiogram and CMR without SWMA; (3) CMR with SWMA independently of electrocardiogram. The number of patients with ventricular arrhythmia in relation to the total of patients, the percentage of fibrosis, and the LVEF were, respectively: Group 1, 4/26, 0.74% and 74.34%; Group 2, 4/16, 3.96% and 68.5%; and Group 3, 11/19, 14.07% and 55.59%. Ventricular arrhythmia was found in 31.1% of the patients. Those with and without ventricular arrhythmia had mean LVEF of 59.87% and 70.18%, respectively, and fibrosis percentage of 11.03% and 3.01%, respectively. Of the variables SWMA, groups, age, LVEF and fibrosis, only the latter was significant for the presence of ventricular arrhythmia, with a cutoff point of 11.78% for fibrosis mass (p < 0.001). Even in patients with Chagas disease and preserved or minimally impaired ventricular function, electrical instability can be present. Regarding the presence of ventricular arrhythmia, fibrosis is the most important variable, its amount being proportional to the complexity of the groups.

Relationship between Fibrosis and Ventricular Arrhythmias in Chagas Heart Disease Without Ventricular Dysfunction

International Nuclear Information System (INIS)

Tassi, Eduardo Marinho; Continentino, Marcelo Abramoff; Nascimento, Emília Matos do; Pereira, Basílio de Bragança; Pedrosa, Roberto Coury

2014-01-01

Patients with Chagas disease and segmental wall motion abnormality (SWMA) have worse prognosis independent of left ventricular ejection fraction (LVEF). Cardiac magnetic resonance (CMR) is currently the best method to detect SWMA and to assess fibrosis. To quantify fibrosis by using late gadolinium enhancement CMR in patients with Chagas disease and preserved or minimally impaired ventricular function (> 45%), and to detect patterns of dependence between fibrosis, SWMA and LVEF in the presence of ventricular arrhythmia. Electrocardiogram, treadmill exercise test, Holter and CMR were carried out in 61 patients, who were divided into three groups as follows: (1) normal electrocardiogram and CMR without SWMA; (2) abnormal electrocardiogram and CMR without SWMA; (3) CMR with SWMA independently of electrocardiogram. The number of patients with ventricular arrhythmia in relation to the total of patients, the percentage of fibrosis, and the LVEF were, respectively: Group 1, 4/26, 0.74% and 74.34%; Group 2, 4/16, 3.96% and 68.5%; and Group 3, 11/19, 14.07% and 55.59%. Ventricular arrhythmia was found in 31.1% of the patients. Those with and without ventricular arrhythmia had mean LVEF of 59.87% and 70.18%, respectively, and fibrosis percentage of 11.03% and 3.01%, respectively. Of the variables SWMA, groups, age, LVEF and fibrosis, only the latter was significant for the presence of ventricular arrhythmia, with a cutoff point of 11.78% for fibrosis mass (p < 0.001). Even in patients with Chagas disease and preserved or minimally impaired ventricular function, electrical instability can be present. Regarding the presence of ventricular arrhythmia, fibrosis is the most important variable, its amount being proportional to the complexity of the groups

Non-sedating antihistamine drugs and cardiac arrhythmias -- biased risk estimates from spontaneous reporting systems?

DEFF Research Database (Denmark)

De Bruin, M L; van Puijenbroek, E P; Egberts, A C G

2002-01-01

AIMS: This study used spontaneous reports of adverse events to estimate the risk for developing cardiac arrhythmias due to the systemic use of non-sedating antihistamine drugs and compared the risk estimate before and after the regulatory action to recall the over-the-counter status of some...... of these drugs. METHODS: All suspected adverse drug reactions (ADRs) reported until July 1999 to the Netherlands Pharmacovigilance Foundation Lareb were used to calculate the ADR reporting odds ratio, defined as the ratio of exposure odds among reported arrhythmia cases, to the exposure odds of other ADRs (non......-sedating antihistamines. In general non-sedating antihistamines are associated with cardiac arrhythmia to a higher extent in comparison with other drugs (ADR reporting odds ratio 2.05 [95% CI: 1.45, 2.89]). The association between arrhythmias and non-sedating antihistamine drugs calculated before 1998...

Non-sedating antihistamine drugs and cardiac arrhythmias -- biased risk estimates from spontaneous reporting systems?

DEFF Research Database (Denmark)

De Bruin, M L; van Puijenbroek, E P; Egberts, A C G

2002-01-01

of these drugs. METHODS: All suspected adverse drug reactions (ADRs) reported until July 1999 to the Netherlands Pharmacovigilance Foundation Lareb were used to calculate the ADR reporting odds ratio, defined as the ratio of exposure odds among reported arrhythmia cases, to the exposure odds of other ADRs (non......-sedating antihistamines. In general non-sedating antihistamines are associated with cardiac arrhythmia to a higher extent in comparison with other drugs (ADR reporting odds ratio 2.05 [95% CI: 1.45, 2.89]). The association between arrhythmias and non-sedating antihistamine drugs calculated before 1998...

Chronic cardiac arrhythmias produced by focused cobalt-60 gamma irradiation of the canine atria

International Nuclear Information System (INIS)

Dick, H.L.H.; Saylor, C.B.; Reeves, M.M.; Davies, M.J.

1979-01-01

Cardiac arrhythmias following exposure of the human heart to ionizing radiation have been reported. Earlier experiments involving irradiation of the hearts of various animals failed to consistently produce similar arrhythmias. In the present work, cobalt-60 irradiation was focused on the interatrial septum of the hearts of 12 dogs. Ten animals developed arrhythmias: These were repetive junctional and atrial tachycardias, repetitive atrial fibrillation, and type one, second-degree atrial ventricular block. The duration varied from 1 to 52 days, with onsets varying from 48 to 146 days postirradiation

Cardiac arrhythmias associated with spinal cord injury

DEFF Research Database (Denmark)

Hector, Sven Magnus; Biering-Sørensen, Tor; Krassioukov, Andrei

2013-01-01

CONTEXT/OBJECTIVES: To review the current literature to reveal the incidence of cardiac arrhythmias and its relation to spinal cord injury (SCI). METHODS: Data source: MEDLINE database, 304 hits, and 32 articles were found to be relevant. The relevant articles all met the inclusion criteria: (1...

The Effect of PM 10 on Ischemia- Reperfusion Induced Arrhythmias in Rats

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Esmat Radmanesh

Full Text Available ABSTRACT Epidemiological studies show that particulate matter (PM is the principal instigator of some adverse clinical symptoms involving cardiovascular diseases. PM exposure can increase experimental infarct size and potentiate myocardial ischemia and arrhythmias in experimental MI models such as ischemia-reperfusion (I/R injury.The present study was aimed to evaluate the effects of particulate matter (PM10 on ischemia- reperfusion induced arrhythmias with emphasis on the protective role of VA as an antioxidant on them. Male Wistar rats were divided into 8 groups (n=10: Control, VAc, Sham, VA, PM1 (0.5 mg/kg, PM2 (2.5 mg/kg, PM3 group (5 mg/kg, PM3 + VA group. Within 48 hours, PM10 was instilled into trachea in two stages. Then the hearts were isolated, transferred to a Langendorff apparatus, and subjected to global ischemia (30 minutes followed by reperfusion (60 minutes. The ischemia- reperfusion induced ventricular arrhythmias were assessed according to the Lambeth conventions.In the present study,the number, incidence and duration of arrhythmiasduring30 minutes ischemia were demonstrated to be more than those in the reperfusion stage. PM exposure increased significantly the number, incidence and duration of arrhythmias in the ischemia and reperfusion duration. Vanillic acid reduced significantly the number, incidence and duration of arrhythmias during the ischemia and reperfusion period.In summary, the results of this study demonstrated that the protective and dysrhythmic effects of VA in the PM exposure rats in I/R model are probably related to its antioxidant properties.

A Novel Automatic Detection System for ECG Arrhythmias Using Maximum Margin Clustering with Immune Evolutionary Algorithm

Directory of Open Access Journals (Sweden)

Bohui Zhu

2013-01-01

Full Text Available This paper presents a novel maximum margin clustering method with immune evolution (IEMMC for automatic diagnosis of electrocardiogram (ECG arrhythmias. This diagnostic system consists of signal processing, feature extraction, and the IEMMC algorithm for clustering of ECG arrhythmias. First, raw ECG signal is processed by an adaptive ECG filter based on wavelet transforms, and waveform of the ECG signal is detected; then, features are extracted from ECG signal to cluster different types of arrhythmias by the IEMMC algorithm. Three types of performance evaluation indicators are used to assess the effect of the IEMMC method for ECG arrhythmias, such as sensitivity, specificity, and accuracy. Compared with K-means and iterSVR algorithms, the IEMMC algorithm reflects better performance not only in clustering result but also in terms of global search ability and convergence ability, which proves its effectiveness for the detection of ECG arrhythmias.

Energetic Systems

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Federal Laboratory Consortium — The Energetic Systems Division provides full-spectrum energetic engineering services (project management, design, analysis, production support, in-service support,...

Electromechanical wave imaging for arrhythmias

International Nuclear Information System (INIS)

Provost, Jean; Nguyen, Vu Thanh-Hieu; Legrand, Diégo; Okrasinski, Stan; Costet, Alexandre; Konofagou, Elisa E; Gambhir, Alok; Garan, Hasan

2011-01-01

Electromechanical wave imaging (EWI) is a novel ultrasound-based imaging modality for mapping of the electromechanical wave (EW), i.e. the transient deformations occurring in immediate response to the electrical activation. The correlation between the EW and the electrical activation has been established in prior studies. However, the methods used previously to map the EW required the reconstruction of images over multiple cardiac cycles, precluding the application of EWI for non-periodic arrhythmias such as fibrillation. In this study, new imaging sequences are developed and applied based on flash- and wide-beam emissions to image the entire heart at very high frame rates (2000 fps) during free breathing in a single heartbeat. The methods are first validated by imaging the heart of an open-chest canine while simultaneously mapping the electrical activation using a 64-electrode basket catheter. Feasibility is then assessed by imaging the atria and ventricles of closed-chest, conscious canines during sinus rhythm and during right-ventricular pacing following atrio-ventricular dissociation, i.e., during a non-periodic rhythm. The EW was validated against electrode measurements in the open-chest case, and followed the expected electrical propagation pattern in the closed-chest setting. These results indicate that EWI can be used for the characterization of non-periodic arrhythmias in conditions similar to the clinical setting, in a single heartbeat, and during free breathing. (fast track communication)

Deep energetic trap states in organic photovoltaic devices

KAUST Repository

Shuttle, Christopher G.; Treat, Neil D.; Douglas, Jessica D.; Frechet, Jean; Chabinyc, Michael L.

2011-01-01

The nature of energetic disorder in organic semiconductors is poorly understood. In photovoltaics, energetic disorder leads to reductions in the open circuit voltage and contributes to other loss processes. In this work, three independent optoelectronic methods were used to determine the long-lived carrier populations in a high efficiency N-alkylthieno[3,4-c]pyrrole-4,6-dione (TPD) based polymer: fullerene solar cell. In the TPD co-polymer, all methods indicate the presence of a long-lived carrier population of ∼ 10 15 cm -3 on timescales ≤100 μs. Additionally, the behavior of these photovoltaic devices under optical bias is consistent with deep energetic lying trap states. Comparative measurements were also performed on high efficiency poly-3-hexylthiophene (P3HT): fullerene solar cells; however a similar long-lived carrier population was not observed. This observation is consistent with a higher acceptor concentration (doping) in P3HT than in the TPD-based copolymer. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Deep energetic trap states in organic photovoltaic devices

KAUST Repository

Shuttle, Christopher G.

2011-11-23

The nature of energetic disorder in organic semiconductors is poorly understood. In photovoltaics, energetic disorder leads to reductions in the open circuit voltage and contributes to other loss processes. In this work, three independent optoelectronic methods were used to determine the long-lived carrier populations in a high efficiency N-alkylthieno[3,4-c]pyrrole-4,6-dione (TPD) based polymer: fullerene solar cell. In the TPD co-polymer, all methods indicate the presence of a long-lived carrier population of ∼ 10 15 cm -3 on timescales ≤100 μs. Additionally, the behavior of these photovoltaic devices under optical bias is consistent with deep energetic lying trap states. Comparative measurements were also performed on high efficiency poly-3-hexylthiophene (P3HT): fullerene solar cells; however a similar long-lived carrier population was not observed. This observation is consistent with a higher acceptor concentration (doping) in P3HT than in the TPD-based copolymer. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Emerging molecular therapies targeting myocardial infarction-related arrhythmias

NARCIS (Netherlands)

Driessen, Helen E.; van Veen, Toon A. B.; Boink, Gerard J. J.

2017-01-01

Cardiac disease is the leading cause of death in the developed world. Ventricular arrhythmias associated with myocardial ischaemia and/or infarction are a major contributor to cardiovascular mortality, and require improved prevention and treatment. Drugs, devices, and radiofrequency catheter

Toxicology Study No. S.0024589d 15, Human Cell Line Activation Test of the Novel Energetic, 3,4 -Dinitropyrazole (DNP)

Science.gov (United States)

2016-04-01

Assay 1 0.259 0.278 Assay 2 0.299 6.3 CD54 and CD86 expression in response to DNP exposure of THP -1 cells Three independent tests were...2 Toxicology Study No. S.0024589d-15, April 2016 Toxicology Directorate Human Cell Line Activation Test of the Novel Energetic 3,4...report. 17-05-2016 Technical Report March 2016-April 2016 Toxicology Study No. S.0024589d-15 Human Cell Line Activation Test of the Novel

Multiclass Classification of Cardiac Arrhythmia Using Improved Feature Selection and SVM Invariants.

Science.gov (United States)

Mustaqeem, Anam; Anwar, Syed Muhammad; Majid, Muahammad

2018-01-01

Arrhythmia is considered a life-threatening disease causing serious health issues in patients, when left untreated. An early diagnosis of arrhythmias would be helpful in saving lives. This study is conducted to classify patients into one of the sixteen subclasses, among which one class represents absence of disease and the other fifteen classes represent electrocardiogram records of various subtypes of arrhythmias. The research is carried out on the dataset taken from the University of California at Irvine Machine Learning Data Repository. The dataset contains a large volume of feature dimensions which are reduced using wrapper based feature selection technique. For multiclass classification, support vector machine (SVM) based approaches including one-against-one (OAO), one-against-all (OAA), and error-correction code (ECC) are employed to detect the presence and absence of arrhythmias. The SVM method results are compared with other standard machine learning classifiers using varying parameters and the performance of the classifiers is evaluated using accuracy, kappa statistics, and root mean square error. The results show that OAO method of SVM outperforms all other classifiers by achieving an accuracy rate of 81.11% when used with 80/20 data split and 92.07% using 90/10 data split option.

Dofetilide: a new drug to control cardiac arrhythmia

DEFF Research Database (Denmark)

Elming, Hanne; Brendorp, Bente; Pedersen, Ole Dyg

2003-01-01

Atrial fibrillation (AF) is the most common cardiac arrhythmia. Mortality, and especially morbidity caused by AF, are major and growing health problems in the western world. AF is strongly associated with arterial hypertension, congestive heart failure, valvular heart disease, ischaemic heart...

Surgical outcome of Fontan conversion and arrhythmia surgery: Need a pacemaker?

Science.gov (United States)

Terada, Takafumi; Sakurai, Hajime; Nonaka, Toshimichi; Sakurai, Takahisa; Sugiura, Junya; Taneichi, Tetsuyoshi; Ohtsuka, Ryohei

2014-07-01

Atrial tachyarrhythmias are frequent complications in the late period after the Fontan procedure, and important risk factors for a poor prognosis. The impact of Fontan conversion and arrhythmia surgery in failed Fontan patients has been described in many reports. We evaluated our experience with Fontan conversion procedures, concomitant arrhythmia surgery, and pacemaker implantation. We reviewed the hospital records of 25 consecutive patients who underwent a Fontan conversion procedure from January 2004 to March 2012. Twenty-four patients had arrhythmia surgery using cryoablation and radiofrequency ablation at the time of conversion. A bilateral atrial maze procedure was performed in 6 patients, right-side maze in 15, and isthmus block in 3. Three patients with a diagnosis of corrected transposition of the great arteries underwent simultaneous pacemaker implantation electively. There was no early death and one late death during a mean follow-up period of 21.2 months. Three tachyarrhythmia recurrences developed, and there were 4 occurrences of sinus bradycardia. Five of these patients required postoperative pacemaker implantation. The mid-term results of Fontan conversion and arrhythmia surgery in our institute were satisfactory. The occurrence of unexpected postoperative pacemaker requirement was high in the patients who underwent a right atrial or bilateral atrial maze procedure. Pacemaker or lead implantation is recommended for patients planned to undergo a right-side or full maze procedure. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Prediction of tonic parasympathetic cardiac control using respiratory sinus arrhythmia: the need for respiratory control

NARCIS (Netherlands)

GROSSMAN, P.; Karemaker, J.; Wieling, W.

1991-01-01

Respiratory sinus arrhythmia (RSA) has received much attention in recent years due to the large body of evidence indicating that variations in this phenomenon represent alterations in parasympathetic cardiac control. Although it appears that respiratory sinus arrhythmia is mediated by vagal

Cardiac arrhythmia detection using combination of heart rate variability analyses and PUCK analysis.

Science.gov (United States)

Mahananto, Faizal; Igasaki, Tomohiko; Murayama, Nobuki

2013-01-01

This paper presents cardiac arrhythmia detection using the combination of a heart rate variability (HRV) analysis and a "potential of unbalanced complex kinetics" (PUCK) analysis. Detection performance was improved by adding features extracted from the PUCK analysis. Initially, R-R interval data were extracted from the original electrocardiogram (ECG) recordings and were cut into small segments and marked as either normal or arrhythmia. HRV analyses then were conducted using the segmented R-R interval data, including a time-domain analysis, frequency-domain analysis, and nonlinear analysis. In addition to the HRV analysis, PUCK analysis, which has been implemented successfully in a foreign exchange market series to characterize change, was employed. A decision-tree algorithm was applied to all of the obtained features for classification. The proposed method was tested using the MIT-BIH arrhythmia database and had an overall classification accuracy of 91.73%. After combining features obtained from the PUCK analysis, the overall accuracy increased to 92.91%. Therefore, we suggest that the use of a PUCK analysis in conjunction with HRV analysis might improve performance accuracy for the detection of cardiac arrhythmia.

Dipyridamole-thallium tests are predictive of severe cardiac arrhythmias in patients with left ventricular hypertrophy

International Nuclear Information System (INIS)

Saragoca, M.A.; Canziani, M.E.; Gil, M.A.; Castiglioni, M.L.; Cassiolato, J.L.; Barbieri, A.; Lima, V.C.; Draibe, S.A.; Martinez, E.E.

1991-01-01

In a population of patients with chronic renal failure (CRF) and a high prevalence of left ventricular hypertrophy (LVH) undergoing chronic hemodialysis, the authors investigated the association between the results of dipyridamole-thallium tests (DTTs) and the occurrence of ventricular arrhythmias. They observed a positive significant association between positive DTTs and the occurrence of severe forms of ventricular arrhythmias. A significant association was also observed between the presence of severe LVH and the occurrence of severe ventricular arrhythmias. However, no association was found between the presence of LVH and the positivity of the DTT. As most of their patients with positive DTTs had unimpaired coronary circulations, they conclude that positive DTTs, although falsely indicative of impaired myocardial blood supply, does have an important clinical relevance, indicating increased risk of morbidity (and, possibly, mortality) due to ventricular arrhythmias in a population of CRF patients submitted to chronic renal function replacement program

Arrhythmia recognition and classification using combined linear and nonlinear features of ECG signals.

Science.gov (United States)

Elhaj, Fatin A; Salim, Naomie; Harris, Arief R; Swee, Tan Tian; Ahmed, Taqwa

2016-04-01

Arrhythmia is a cardiac condition caused by abnormal electrical activity of the heart, and an electrocardiogram (ECG) is the non-invasive method used to detect arrhythmias or heart abnormalities. Due to the presence of noise, the non-stationary nature of the ECG signal (i.e. the changing morphology of the ECG signal with respect to time) and the irregularity of the heartbeat, physicians face difficulties in the diagnosis of arrhythmias. The computer-aided analysis of ECG results assists physicians to detect cardiovascular diseases. The development of many existing arrhythmia systems has depended on the findings from linear experiments on ECG data which achieve high performance on noise-free data. However, nonlinear experiments characterize the ECG signal more effectively sense, extract hidden information in the ECG signal, and achieve good performance under noisy conditions. This paper investigates the representation ability of linear and nonlinear features and proposes a combination of such features in order to improve the classification of ECG data. In this study, five types of beat classes of arrhythmia as recommended by the Association for Advancement of Medical Instrumentation are analyzed: non-ectopic beats (N), supra-ventricular ectopic beats (S), ventricular ectopic beats (V), fusion beats (F) and unclassifiable and paced beats (U). The characterization ability of nonlinear features such as high order statistics and cumulants and nonlinear feature reduction methods such as independent component analysis are combined with linear features, namely, the principal component analysis of discrete wavelet transform coefficients. The features are tested for their ability to differentiate different classes of data using different classifiers, namely, the support vector machine and neural network methods with tenfold cross-validation. Our proposed method is able to classify the N, S, V, F and U arrhythmia classes with high accuracy (98.91%) using a combined support

Ischaemic stroke in hyperthyroidism without cardiac arrhythmia - A ...

African Journals Online (AJOL)

BACKGROUND: The relationship between hyperthyroidism and stroke is well established in the setting of atrial fibrillation. However there is limited literature for ischaemic stroke occurring in hyperthyroidism without cardiac arrhythmia. No such case had been described in South East Nigeria. METHOD: This report highlights ...

Detection of Life Threatening Ventricular Arrhythmia Using Digital Taylor Fourier Transform.

Science.gov (United States)

Tripathy, Rajesh K; Zamora-Mendez, Alejandro; de la O Serna, José A; Paternina, Mario R Arrieta; Arrieta, Juan G; Naik, Ganesh R

2018-01-01

Accurate detection and classification of life-threatening ventricular arrhythmia episodes such as ventricular fibrillation (VF) and rapid ventricular tachycardia (VT) from electrocardiogram (ECG) is a challenging problem for patient monitoring and defibrillation therapy. This paper introduces a novel method for detection and classification of life-threatening ventricular arrhythmia episodes. The ECG signal is decomposed into various oscillatory modes using digital Taylor-Fourier transform (DTFT). The magnitude feature and a novel phase feature namely the phase difference (PD) are evaluated from the mode Taylor-Fourier coefficients of ECG signal. The least square support vector machine (LS-SVM) classifier with linear and radial basis function (RBF) kernels is employed for detection and classification of VT vs. VF, non-shock vs. shock and VF vs. non-VF arrhythmia episodes. The accuracy, sensitivity, and specificity values obtained using the proposed method are 89.81, 86.38, and 93.97%, respectively for the classification of Non-VF and VF episodes. Comparison with the performance of the state-of-the-art features demonstrate the advantages of the proposition.

Loperamide Induced Life Threatening Ventricular Arrhythmia

Directory of Open Access Journals (Sweden)

Ankit Upadhyay

2016-01-01

Full Text Available Loperamide is over-the-counter antidiarrheal agent acting on peripherally located μ opioid receptors. It is gaining popularity among drug abusers as opioid substitute. We report a case of a 46-year-old male that was presented after cardiac arrest. After ruling out ischemia, cardiomyopathy, pulmonary embolism, central nervous system pathology, sepsis, and other drug toxicity, we found out that patient was using around 100 mg of Loperamide to control his chronic diarrhea presumably because of irritable bowel syndrome for last five years and consumed up to 200 mg of Loperamide daily for last two days before the cardiac arrest. We hypothesize that the patient’s QTc prolongation and subsequent cardiac arrest are due to Loperamide toxicity. Patient experienced gradual resolution of tachyarrhythmia and gradual decrease in QTc interval during hospitalization which supports the evidence of causal relationship between Loperamide overdose and potentially fatal arrhythmias. It also provided the clue that patient may have congenital long QT syndrome which was unmasked by Loperamide causing ventricular arrhythmias. This case adds one more pearl in the literature to support that Loperamide overdose related cardiac toxicity does exist and it raises concerns over Loperamide abuse in the community.

Statins as anti-arrhythmics: a systematic review part II: effects on risk of ventricular arrhythmias.

Science.gov (United States)

Abuissa, Hussam; O'Keefe, James H; Bybee, Kevin A

2009-10-01

Recent studies have demonstrated that statins may possess anti-arrhythmic properties in addition to their lipid-lowering effects. Studies which reported the association of statins with the incidence of ventricular arrhythmias were identified through a systematic review of the published literature. Statins have been associated with a significant reductions in ventricular arrhythmia in cardiomyopathy patients with an implantable cardioverter defibrillator, although randomized trials have not been completed. Published data suggests that statins may possess anti-arrhythmic properties that reduce the propensity for ventricular arrhythmias. Most of this data is observational; more randomized, placebo-controlled trials are needed.

Double hazards of ischemia and reperfusion arrhythmias in a patient with variant angina pectoris.

Science.gov (United States)

Xu, Mingzhu; Yang, Xiangjun

2015-01-01

Variant angina pectoris, also called Prinzmetal's angina, is a syndrome caused by vasospasms of the coronary arteries. It can lead to myocardial infarction, ventricular arrhythmias, atrioventricular block and even sudden cardiac death. We report the case of a 53 year-old male patient with recurrent episodes of chest pain and arrhythmias in the course of related variant angina pectoris. It is likely that the reperfusion following myocardial ischemia was responsible for the ventricular fibrillation while the ST-segment returned to the baseline. This case showed that potential lethal arrhythmias could arise due to variant angina pectoris. It also indicated that ventricular fibrillation could be self-terminated. Copyright © 2015 Elsevier Inc. All rights reserved.

Decreasing the false alarm rate of arrhythmias in intensive care using a machine learning approach

NARCIS (Netherlands)

Eerikäinen, L.M.; Vanschoren, J.; Rooijakkers, M.J.; Vullings, R.; Aarts, R.M.

2015-01-01

We present a novel algorithm for classifying true and false alarms of five life-threatening arrhythmias in intensive care. This algorithm was entered in the PhysioNet/Computing in Cardiology Challenge 2015 Reducing False Arrhythmia Alarms in the ICU. The algorithm performs a binary classification of

Risk prediction of ventricular arrhythmias and myocardial function in Lamin A/C mutation positive subjects

DEFF Research Database (Denmark)

Hasselberg, Nina E; Edvardsen, Thor; Petri, Helle

2014-01-01

Mutations in the Lamin A/C gene may cause atrioventricular block, supraventricular arrhythmias, ventricular arrhythmias (VA), and dilated cardiomyopathy. We aimed to explore the predictors and the mechanisms of VA in Lamin A/C mutation-positive subjects.METHODS AND RESULTS: We included 41 Lamin A/C...

Automated testing of arrhythmia monitors using annotated databases.

Science.gov (United States)

Elghazzawi, Z; Murray, W; Porter, M; Ezekiel, E; Goodall, M; Staats, S; Geheb, F

1992-01-01

Arrhythmia-algorithm performance is typically tested using the AHA and MIT/BIH databases. The tools for this test are simulation software programs. While these simulations provide rapid results, they neglect hardware and software effects in the monitor. To provide a more accurate measure of performance in the actual monitor, a system has been developed for automated arrhythmia testing. The testing system incorporates an IBM-compatible personal computer, a digital-to-analog converter, an RS232 board, a patient-simulator interface to the monitor, and a multi-tasking software package for data conversion and communication with the monitor. This system "plays" patient data files into the monitor and saves beat classifications in detection files. Tests were performed using the MIT/BIH and AHA databases. Statistics were generated by comparing the detection files with the annotation files. These statistics were marginally different from those that resulted from the simulation. Differences were then examined. As expected, the differences were related to monitor hardware effects.

[Clinical aspects of reperfusion arrhythmia following intravenous thrombolysis in acute myocardial infarct].

Science.gov (United States)

Kettner, W; Klein, E; Schulz, W; Götze, C

1987-05-15

In accordance with the majority of the reports in the literature reperfusion arrhythmias were observed in more than 30% of the patients with acute myocardial infarction (n = 25) under or immediately after a highly dosed short-term infusion with streptokinase. With reference to indirect signs the recanalisation rate was assumed with 75%. Only one third of the reperfusion arrhythmias had haemodynamically significant characteristics and required an influence. Though in literature from animal experimental findings directive conclusions for the therapy are to be derived, the procedure in practice is still vastly empirical. In the ventricular tachycardia lidocaine, procainamide and ajmalin may be recommended. In ineffectiveness or particularly threatening situations the electrotherapy (cardioversion, DC-shock) is to be preferred. The concept inaugurated by Corr and Witkowski apply alpha-adrenoreceptor blockers has not yet entered the clinical practice. Possible problems in the treatment of reperfusion arrhythmias in the prehospital phase should at present still be a reason not to antedate the thrombolytic therapy into this phase.

Ubiquitous health monitoring and real-time cardiac arrhythmias detection: a case study.

Science.gov (United States)

Li, Jian; Zhou, Haiying; Zuo, Decheng; Hou, Kun-Mean; De Vaulx, Christophe

2014-01-01

As the symptoms and signs of heart diseases that cause sudden cardiac death, cardiac arrhythmia has attracted great attention. Due to limitations in time and space, traditional approaches to cardiac arrhythmias detection fail to provide a real-time continuous monitoring and testing service applicable in different environmental conditions. Integrated with the latest technologies in ECG (electrocardiograph) analysis and medical care, the pervasive computing technology makes possible the ubiquitous cardiac care services, and thus brings about new technical challenges, especially in the formation of cardiac care architecture and realization of the real-time automatic ECG detection algorithm dedicated to care devices. In this paper, a ubiquitous cardiac care prototype system is presented with its architecture framework well elaborated. This prototype system has been tested and evaluated in all the clinical-/home-/outdoor-care modes with a satisfactory performance in providing real-time continuous cardiac arrhythmias monitoring service unlimitedly adaptable in time and space.

Magnesium sulphate and amiodarone prophylaxis for prevention of postoperative arrhythmia in coronary by-pass operations

Directory of Open Access Journals (Sweden)

Huysal Kagan

2009-02-01

Full Text Available Abstract Background The aim of this study was to investigate the use of prophylactic magnesium sulphate and amiodarone in treating arrhythmias that may occur following coronary bypass grafting operations. Methods The study population consisted of 192 consecutive patients who were undergoing coronary artery bypass grafting (CABG. Sixty-four patients were given 3 g of magnesium sulphate (MgSO4 [20 ml = 24.32 mEq/L Mg+2] in 100 cc of isotonic 0.9% solution over 2 hours intravenously at the following times: 12 hours prior to the operation, immediately following the operation, and on postoperative days 1, 2, and 3 (Group 1. Another group of 64 patients was given a preoperative infusion of amiodarone (1200 mg on first post-operative day (Group 2. After the operation amiodarone was administered orally at a dose of 600 mg/day. Sixty-four patients in group 3 (control group had 100 cc. isotonic 0.9% as placebo, during the same time periods. Results In the postoperative period, the magnesium values were significantly higher in Group 1 than in Group 2 for all measurements. The use of amiodarone for total arrhythmia was significantly more effective than prophylactic treatment with magnesium sulphate (p = 0.015. There was no difference between the two drugs in preventing supraventricular arrhythmia, although amiodarone significantly delayed the revealing time of atrial fibrillation (p = 0.026. Ventricular arrhythmia, in the form of ventricular extra systole, was more common in the magnesium prophylaxis group. The two groups showed no significant differences in other operative or postoperative measurements. No side effects of the drugs were observed. Conclusion Prophylactic use of magnesium sulphate and amiodarone are both effective at preventing arrhythmia that may occur following coronary by-pass operations. Magnesium sulphate should be used in prophylactic treatment since it may decrease arrhythmia at low doses. If arrhythmia should occur despite this

Life threatening arrhythmias: Knowledge and skills among nurses ...

African Journals Online (AJOL)

Conclusion: Although the majority of the participants scored highly in their level of knowledge regarding life threatening arrhythmias, they scored poorly in most of the observed skills when identifying and treating this patient group. It is important that hospital administration take into consideration the identified areas of ...

Life threatening arrhythmias: Knowledge and skills among nurses ...

African Journals Online (AJOL)

User

this study was to assess knowledge and skills of nurses in identifying life ... Much of the literature considers ventricular tachycardia, ventricular fibrillation, ... In critical care settings, bedside nurses play a critical role in arrhythmia identification and ..... Lambert, V.A. & Lambert, C.E. (2008) Nurses' workplace stressors and ...

Intracoronary infusion of catecholamines causes focal arrhythmias in pigs.

Science.gov (United States)

Doppalapudi, Harish; Jin, Qi; Dosdall, Derek J; Qin, Hao; Walcott, Gregory P; Killingsworth, Cheryl R; Smith, William M; Ideker, Raymond E; Huang, Jian

2008-09-01

Acute ischemia causes myriad changes including increased catecholamines. We tested the hypothesis that elevated catecholamines alone are arrhythmogenic. A 504 electrode sock was placed over both ventricles in six open-chest pigs. During control infusion of saline through a catheter in the left anterior descending coronary artery (LAD), no sustained arrhythmias occurred, and the refractory period estimated by the activation recovery interval (ARI) was 175 +/- 14 ms in the LAD bed below the catheter. After infusion of isoproterenol at 0.1 microg/kg/min through the catheter, the ARI in this bed was significantly reduced to 109 +/- 10 ms. A sharp gradient of refractoriness of 43 +/- 10 ms was at the border of the perfused bed. Sustained monomorphic ventricular tachycardia occurred after drug infusion in the perfused bed or near its boundary in all animals with a cycle length of 329 +/- 26 ms and a focal origin. The maximum slope of the ARI restitution curve at the focal origins of the tachyarrhythmias was always <1 (0.62 +/- 0.15). Similar results with a focal arrhythmia origin occurred in two additional pigs in which intramural mapping was performed with 36 plunge needle electrodes in the left ventricular perfused bed. Regional elevation of a catecholamine, which is one of the alterations produced by acute ischemia, can by itself cause tachyarrhythmias. These arrhythmias are closely associated with a shortened refractory period and a large gradient of the spatial distribution of refractoriness but not with a steep restitution curve.

Evaluation of heart rhythm variability and arrhythmia in children with systemic and localized scleroderma.

Science.gov (United States)

Wozniak, Jacek; Dabrowski, Rafal; Luczak, Dariusz; Kwiatkowska, Malgorzata; Musiej-Nowakowska, Elzbieta; Kowalik, Ilona; Szwed, Hanna

2009-01-01

To evaluate possible disturbances in autonomic regulation and cardiac arrhythmias in children with localized and systemic scleroderma. There were 40 children included in the study: 20 with systemic and 20 with localized scleroderma. The control group comprised 20 healthy children. In 24-hour Holter recording, the average rate of sinus rhythm was significantly higher in the groups with systemic and localized scleroderma than in the control group, but there was no significant difference between them. The variability of heart rhythm in both groups was significantly decreased. In the group with systemic scleroderma, single supraventricular ectopic beats were observed in 20% and runs were seen in 40% of patients. In the group with localized scleroderma, supraventricular single ectopic beats occurred in 35% of patients and runs in 45% of those studied. Ventricular arrhythmia occurred in 2 children with systemic scleroderma, but in 1 child, it was complex. The most frequent cardiac arrhythmias in both types of scleroderma in children were of supraventricular origin, whereas ventricular arrhythmias did not occur very often. There were no significant differences in autonomic disturbances manifesting as a higher heart rate and decreased heart rate variability between localized and systemic scleroderma.

Discrete potentials guided radiofrequency ablation for idiopathic outflow tract ventricular arrhythmias.

Science.gov (United States)

Liu, Enzhao; Xu, Gang; Liu, Tong; Ye, Lan; Zhang, Qitong; Zhao, Yanshu; Li, Guangping

2015-03-01

Discrete potentials (DPs) have been recorded and targeted as the site of ablation of the outflow tract arrhythmias. The aim of the present study was to investigate the significance of DPs with respect to mapping and ablation for idiopathic outflow tract premature ventricular contractions (PVCs) or ventricular tachycardias (VTs). Seventeen consecutive patients with idiopathic right or left ventricular outflow tract PVCs/VTs who underwent radiofrequency catheter ablation were included. Intracardiac electrograms during the mapping and ablation were analysed. During sinus rhythm, sharp high-frequency DPs that displayed double or multiple components were recorded following or buried in the local ventricular electrograms in all of the 17 patients, peak amplitude 0.51 ± 0.21 mV. The same potential was recorded prior to the local ventricular potential of the PVCs/VTs. Spontaneous reversal of the relationship of the DPs to the local ventricular electrogram during the arrhythmias was noted. The DPs were related to a region of low voltage showed by intracardiac high-density contact mapping. At the sites with DPs, lower unipolar and bipolar ventricular voltage of sinus beats were noted compared with the adjacent regions without DPs (unipolar: 6.1 ± 1.8 vs. 8.3 ± 2.3 mV, P Discrete potentials were not present in seven controls. Discrete potentials and related low-voltage regions were common in idiopathic outflow tract ventricular arrhythmias. Discrete potential- and substrate-guided ablation strategy will help to reduce the recurrence of idiopathic outflow tract arrhythmias. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

Temporal abstraction and inductive logic programming for arrhythmia recognition from electrocardiograms.

Science.gov (United States)

Carrault, G; Cordier, M-O; Quiniou, R; Wang, F

2003-07-01

This paper proposes a novel approach to cardiac arrhythmia recognition from electrocardiograms (ECGs). ECGs record the electrical activity of the heart and are used to diagnose many heart disorders. The numerical ECG is first temporally abstracted into series of time-stamped events. Temporal abstraction makes use of artificial neural networks to extract interesting waves and their features from the input signals. A temporal reasoner called a chronicle recogniser processes such series in order to discover temporal patterns called chronicles which can be related to cardiac arrhythmias. Generally, it is difficult to elicit an accurate set of chronicles from a doctor. Thus, we propose to learn automatically from symbolic ECG examples the chronicles discriminating the arrhythmias belonging to some specific subset. Since temporal relationships are of major importance, inductive logic programming (ILP) is the tool of choice as it enables first-order relational learning. The approach has been evaluated on real ECGs taken from the MIT-BIH database. The performance of the different modules as well as the efficiency of the whole system is presented. The results are rather good and demonstrate that integrating numerical techniques for low level perception and symbolic techniques for high level classification is very valuable.

Electroversion in treatment of arrhythmia in a patient with Wolff-Parkinson-White syndrome and cervical spinal cord injury

Directory of Open Access Journals (Sweden)

SHEN Peng

2013-06-01

Full Text Available 【Abstract】We report electroversion in treatment of atrial fibrillation (AF and atrioventricular nodal reentry ta-chycardia (AVNRT in a patient with Wolff-Parkinson-White syndrome and cervical spinal cord injury. At first, the pa-tient sustained respiratory failure and weak cough reflex, thereafter repeated bronchoscopy was used to aspirate the sputum as well as control the pneumonia, which resulted in arrhythmia (AF and AVNRT. Two doses of intravenous amiodarone failed to correct the arrhythmia. After restora-tion of sinus rhythm by electroversion, he was successfully weaned from mechanical ventilation and discharged from the intensive care unit without recurrent arrhythmia. Key words: Arrhythmia, cardiac; Atrial fibrillation; Electric countershock; Wolff-Parkinson-White syndrome; Spinal cord injuries

The effect of Cardiac Arrhythmias Simulation Software on the nurses' learning and professional development.

Science.gov (United States)

Bazrafkan, Leila; Hemmati, Mehdi

2018-04-01

One of the important tasks of nurses in intensive care unit is interpretation of ECG. The use of training simulator is a new paradigm in the age of computers. This study was performed to evaluate the impact of cardiac arrhythmias simulator software on nurses' learning in the subspecialty Vali-Asr Hospital in 2016. This study was conducted by quasi-experimental randomized Salomon four group design with the participation of 120 nurses in subspecialty Vali-Asr Hospital in Tehran, Iran in 2016 that were selected purposefully and allocated in 4 groups. By this design other confounding factors such as the prior information, maturation and the role of sex and age were controlled by Solomon 4 design. The valid and reliable multiple choice test tools were used to gather information; the validity of the test was approved by experts and its reliability was obtained by Cronbach's alpha coefficient 0.89. At first, the knowledge and skills of the participants were assessed by a pre-test; following the educational intervention with cardiac arrhythmias simulator software during 14 days in ICUs, the mentioned factors were measured for the two groups again by a post-test in the four groups. Data were analyzed using the two way ANOVA. The significance level was considered as ptest results, using cardiac arrhythmias simulator software as an intervention was effective in the nurses' learning since a significant difference was found between pre-test and post-test in the first group (ptest showed that there was no interaction between pre-test and intervention in all of the three knowledge areas of cardiac arrhythmias, their treatments and their diagnosis (P>0.05). The use of software-based simulator for cardiac arrhythmias was effective in nurses' learning in light of its attractive components and interactive method. This intervention increased the knowledge of the nurses in cognitive domain of cardiac arrhythmias in addition to their diagnosis and treatment. Also, the package can be

Energetic materials and methods of tailoring electrostatic discharge sensitivity of energetic materials

Energy Technology Data Exchange (ETDEWEB)

Daniels, Michael A.; Heaps, Ronald J.; Wallace, Ronald S.; Pantoya, Michelle L.; Collins, Eric S.

2016-11-01

An energetic material comprising an elemental fuel, an oxidizer or other element, and a carbon nanofiller or carbon fiber rods, where the carbon nanofiller or carbon fiber rods are substantially homogeneously dispersed in the energetic material. Methods of tailoring the electrostatic discharge sensitivity of an energetic material are also disclosed.

Novel energy modalities for catheter ablation of cardiac arrhythmias : Pitfalls and possibilities of potent power sources

NARCIS (Netherlands)

Neven, K.G.E.J.

2014-01-01

The acceptance of catheter ablation as treatment for cardiac arrhythmias is amongst others dependent on its success rate, a high initial success rate will increase physician and patient acceptance. One of the reasons why recurrence of arrhythmia after ablation is substantial is non-transmurality of

Effects of short-term administration of estradiol on reperfusion arrhythmias in rats of different ages

International Nuclear Information System (INIS)

Savergnini, S.Q.; Reis, A.M.; Santos, R.A.S.; Santos, P.E.B.; Ferreira, A.J.; Almeida, A.P.

2012-01-01

Little is known about age-related differences in short-term effects of estradiol on ischemia-reperfusion (I/R) insults. The present study was designed to evaluate the effects of short-term treatment with estradiol on reperfusion arrhythmias in isolated hearts of 6-7-week-old and 12-14-month-old female rats. Wistar rats were sham-operated, ovariectomized and treated with vehicle or ovariectomized and treated with 17β-estradiol (E 2 ; 5 µg·100 g −1 ·day −1 ) for 4 days. Hearts were perfused by the Langendorff technique. Reperfusion arrhythmias, i.e., ventricular tachycardia and/or ventricular fibrillation, were induced by 15 min of left coronary artery ligation and 30 min of reperfusion. The duration and incidence of I/R arrhythmias were significantly higher in young rats compared to middle-aged rats (arrhythmia severity index: 9.4 ± 1.0 vs 3.0 ± 0.3 arbitrary units, respectively, P < 0.05). In addition, middle-aged rats showed lower heart rate, systolic tension and coronary flow. Four-day E 2 treatment caused an increase in uterine weight. Although E 2 administration had no significant effect on the duration of I/R arrhythmias in middle-aged rats, it induced a marked reduction in the rhythm disturbances of young rats accompanied by a decrease in heart rate of isolated hearts. Also, this reduction was associated with an increase in QT interval. No significant changes were observed in the QT interval of middle-aged E 2 -treated rats. These data demonstrate that short-term estradiol treatment protects against I/R arrhythmias in hearts of young female rats. The anti-arrhythmogenic effect of estradiol might be related to a lengthening of the QT interval

Effects of short-term administration of estradiol on reperfusion arrhythmias in rats of different ages

Energy Technology Data Exchange (ETDEWEB)

Savergnini, S.Q.; Reis, A.M. [Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil); Santos, R.A.S. [1Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil); Santos, P.E.B. [Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil); Ferreira, A.J. [Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil); Almeida, A.P. [Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil)

2012-11-01

Little is known about age-related differences in short-term effects of estradiol on ischemia-reperfusion (I/R) insults. The present study was designed to evaluate the effects of short-term treatment with estradiol on reperfusion arrhythmias in isolated hearts of 6-7-week-old and 12-14-month-old female rats. Wistar rats were sham-operated, ovariectomized and treated with vehicle or ovariectomized and treated with 17β-estradiol (E{sub 2}; 5 µg·100 g{sup −1}·day{sup −1}) for 4 days. Hearts were perfused by the Langendorff technique. Reperfusion arrhythmias, i.e., ventricular tachycardia and/or ventricular fibrillation, were induced by 15 min of left coronary artery ligation and 30 min of reperfusion. The duration and incidence of I/R arrhythmias were significantly higher in young rats compared to middle-aged rats (arrhythmia severity index: 9.4 ± 1.0 vs 3.0 ± 0.3 arbitrary units, respectively, P < 0.05). In addition, middle-aged rats showed lower heart rate, systolic tension and coronary flow. Four-day E{sub 2} treatment caused an increase in uterine weight. Although E{sub 2} administration had no significant effect on the duration of I/R arrhythmias in middle-aged rats, it induced a marked reduction in the rhythm disturbances of young rats accompanied by a decrease in heart rate of isolated hearts. Also, this reduction was associated with an increase in QT interval. No significant changes were observed in the QT interval of middle-aged E{sub 2}-treated rats. These data demonstrate that short-term estradiol treatment protects against I/R arrhythmias in hearts of young female rats. The anti-arrhythmogenic effect of estradiol might be related to a lengthening of the QT interval.

Symmetrical compression distance for arrhythmia discrimination in cloud-based big-data services.

Science.gov (United States)

Lillo-Castellano, J M; Mora-Jiménez, I; Santiago-Mozos, R; Chavarría-Asso, F; Cano-González, A; García-Alberola, A; Rojo-Álvarez, J L

2015-07-01

The current development of cloud computing is completely changing the paradigm of data knowledge extraction in huge databases. An example of this technology in the cardiac arrhythmia field is the SCOOP platform, a national-level scientific cloud-based big data service for implantable cardioverter defibrillators. In this scenario, we here propose a new methodology for automatic classification of intracardiac electrograms (EGMs) in a cloud computing system, designed for minimal signal preprocessing. A new compression-based similarity measure (CSM) is created for low computational burden, so-called weighted fast compression distance, which provides better performance when compared with other CSMs in the literature. Using simple machine learning techniques, a set of 6848 EGMs extracted from SCOOP platform were classified into seven cardiac arrhythmia classes and one noise class, reaching near to 90% accuracy when previous patient arrhythmia information was available and 63% otherwise, hence overcoming in all cases the classification provided by the majority class. Results show that this methodology can be used as a high-quality service of cloud computing, providing support to physicians for improving the knowledge on patient diagnosis.

Combination of opium smoking and hypercholesterolemia augments susceptibility for lethal cardiac arrhythmia and atherogenesis in rabbit.

Science.gov (United States)

Najafipour, Hamid; Joukar, Siyavash

2012-09-01

Opium consumption is increasing in some eastern societies, where it is grown. We investigated the effect of opium smoking on plasma atherogenic index and incidence of lethal cardiac arrhythmia, i.e. ventricular tachycardia (VT) and ventricular fibrillation (VF) in rabbits. Animals were divided into two-, normo- and hyper-cholesterolemic main groups fed with normal or high cholesterol diet prior and during short-term and long-term exposure to opium smoke. Then, isoproterenol (3mg/kg, i.p.) was injected to induce cardiac ischemia and animals were followed for 3h for counting of lethal arrhythmia incidence. Long-term opium smoking significantly increased the plasma atherogenic index. In ischemic hearts, opium smoking along with hypercholesterolemia significantly enhanced the incidence of fatal arrhythmia. This vulnerability was not mediated by changes in QT interval. These data suggest that opium smoking, especially in hypercholesterolemic conditions, can be a predisposing factor for atherogenesis and lethal arrhythmia. Copyright © 2012 Elsevier B.V. All rights reserved.

Energetics Conditioning Facility

Data.gov (United States)

Federal Laboratory Consortium — The Energetics Conditioning Facility is used for long term and short term aging studies of energetic materials. The facility has 10 conditioning chambers of which 2...

Nonclinical cardiovascular safety of pitolisant: comparing International Conference on Harmonization S7B and Comprehensive in vitro Pro-arrhythmia Assay initiative studies.

Science.gov (United States)

Ligneau, Xavier; Shah, Rashmi R; Berrebi-Bertrand, Isabelle; Mirams, Gary R; Robert, Philippe; Landais, Laurent; Maison-Blanche, Pierre; Faivre, Jean-François; Lecomte, Jeanne-Marie; Schwartz, Jean-Charles

2017-12-01

We evaluated the concordance of results from two sets of nonclinical cardiovascular safety studies on pitolisant. Nonclinical studies envisaged both in the International Conference on Harmonization (ICH) S7B guideline and Comprehensive in vitro Pro-arrhythmia Assay (CiPA) initiative were undertaken. The CiPA initiative included in vitro ion channels, stem cell-derived human ventricular myocytes, and in silico modelling to simulate human ventricular electrophysiology. ICH S7B-recommended assays included in vitro hERG (K V 11.1) channels, in vivo dog studies with follow-up investigations in rabbit Purkinje fibres and the in vivo Carlsson rabbit pro-arrhythmia model. Both sets of nonclinical data consistently excluded pitolisant from having clinically relevant QT-liability or pro-arrhythmic potential. CiPA studies revealed pitolisant to have modest calcium channel blocking and late I Na reducing activities at high concentrations, which resulted in pitolisant reducing dofetilide-induced early after-depolarizations (EADs) in the ICH S7B studies. Studies in stem cell-derived human cardiomyocytes with dofetilide or E-4031 given alone and in combination with pitolisant confirmed these properties. In silico modelling confirmed that the ion channel effects measured are consistent with results from both the stem cell-derived cardiomyocytes and rabbit Purkinje fibres and categorized pitolisant as a drug with low torsadogenic potential. Results from the two sets of nonclinical studies correlated well with those from two clinical QT studies. Our findings support the CiPA initiative but suggest that sponsors should consider investigating drug effects on EADs and the use of pro-arrhythmia models when the results from CiPA studies are ambiguous. © 2017 The Authors. British Journal of Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.

Arctigenin, a Potential Anti-Arrhythmic Agent, Inhibits Aconitine-Induced Arrhythmia by Regulating Multi-Ion Channels

Directory of Open Access Journals (Sweden)

Zhenying Zhao

2013-11-01

Full Text Available Background/Aims: Arctigenin possesses biological activities, but its underlying mechanisms at the cellular and ion channel levels are not completely understood. Therefore, the present study was designed to identify the anti-arrhythmia effect of arctigenin in vivo, as well as its cellular targets and mechanisms. Methods: A rat arrhythmia model was established via continuous aconitine infusion, and the onset times of ventricular premature contraction, ventricular tachycardia and death were recorded. The Action Potential Duration (APD, sodium current (INa, L-type calcium current (ICa, L and transient outward potassium current (Ito were measured and analysed using a patch-clamp recording technique in normal rat cardiomyocytes and myocytes of arrhythmia aconitine-induced by. Results: Arctigenin significantly delayed the arrhythmia onset in the aconitine-induced rat model. The 50% and 90% repolarisations (APD50 and APD90 were shortened by 100 µM arctigenin; the arctigenin dose also inhibited the prolongation of APD50 and APD90 caused by 1 µM aconitine. Arctigenin inhibited INa and ICa,L and attenuated the aconitine-increased INa and ICa,L by accelerating the activation process and delaying the inactivation process. Arctigenin enhanced Ito by facilitating the activation process and delaying the inactivation process, and recoverd the decreased Ito induced by aconitine. Conclusions: Arctigenin has displayed anti-arrhythmia effects, both in vivo and in vitro. In the context of electrophysiology, INa, ICa, L, and Ito may be multiple targets of arctigenin, leading to its antiarrhythmic effect.

Comparison of two teaching methods for cardiac arrhythmia interpretation among nursing students.

Science.gov (United States)

Varvaroussis, Dimitrios P; Kalafati, Maria; Pliatsika, Paraskevi; Castrén, Maaret; Lott, Carsten; Xanthos, Theodoros

2014-02-01

The aim of this study was to compare the six-stage method (SSM) for instructing primary cardiac arrhythmias interpretation to students without basic electrocardiogram (ECG) knowledge with a descriptive teaching method in a single educational intervention. This is a randomized trial. Following a brief instructional session, undergraduate nursing students, assigned to group A (SSM) and group B (descriptive teaching method), undertook a written test in cardiac rhythm recognition, immediately after the educational intervention (initial exam). Participants were also examined with an unannounced retention test (final exam), one month after instruction. Altogether 134 students completed the study. Interpretation accuracy for each cardiac arrhythmia was assessed. Mean score at the initial exam was 8.71±1.285 for group A and 8.74±1.303 for group B. Mean score at the final exam was 8.25±1.46 for group A vs 7.84±1.44 for group B. Overall results showed that the SSM was equally effective with the descriptive teaching method. The study showed that in each group bradyarrhythmias were identified correctly by more students than tachyarrhythmias. No significant difference between the two teaching methods was seen for any specific cardiac arrhythmia. The SSM effectively develops staff competency for interpreting common cardiac arrhythmias in students without ECG knowledge. More research is needed to support this conclusion and the method's effectiveness must be evaluated if being implemented to trainee groups with preexisting basic ECG interpretation knowledge. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Cardiac Arrhythmia: Atrial Flutter in a Newborn. Case Study

Directory of Open Access Journals (Sweden)

T.M. Klimenko

2014-09-01

Full Text Available The article gives case report of rare in neonatal period cardiac arrhythmia — atrial flutter. The disease is one of the manifestations of life-threatening heart rhythm disorders, has no characteristic clinical picture, is diagnosed only by means of an electrocardiogram.

[Intravenous nitroglycerin infusion suppresses exercise-induced arrhythmia in patients with ischemic cardiopathy: indications for chronic treatment ].

Science.gov (United States)

Bonetti, F; Margonato, A; Mailhac, A; Vicedomini, G; Cianflone, D; Scarpazza, P; Chierchia, S L

1990-05-01

In patients with ischemic heart disease and arrhythmias, selection of antiarrhythmic treatment is often difficult as it is hard to separate "primary" from ischemic arrhythmias. We studied 20 patients with ischemic heart disease, who developed ventricular arrhythmias consistently during exercise test. Exercise test was performed twice during infusion of placebo and then during intravenous administration of nitroglycerin, titrated to reduce systolic blood pressure by 10 mmHg. Exercise duration was 7.8 +/- 1.7 and 7.9 +/- 1.5 min, in the 2 placebo tests (NS). Angina developed in 5 patients and ischemic ST changes in 10. With nitroglycerin exercise duration increased to 8.4 +/- 20 min (p less than 0.05), diagnostic ST segment depression was observed in 2 patients and only 1 had angina. In all 20 patients, ventricular arrhythmias were consistently present during both tests on placebo, that were markedly reduced by nitroglycerin. In fact, ventricular ectopic beats were 455 (mean 35.8 +/- 16.8) and 418 (mean 34.4 +/- 11.1) in the 2 exercise tests with placebo, and 11 during nitroglycerin infusion (mean 0.6 +/- 0.1; p less than 0.001). Couplets were 28 and 29 during placebo (NS) and 0 during nitroglycerin (p less than 0.001). Ventricular tachycardia was present in 6 and 8 patients during placebo but in none during nitroglycerin (p less than 0.001). Reduction of exercise-induced arrhythmias was maintained during chronic treatment with oral vasodilators. Prevention of exercise-related arrhythmias by nitroglycerin infusion appears a good indicator of their ischemic origin and may provide valuable information for long-term profilaxis with oral vasodilators, then avoiding the use of antiarrhythmic agents and their potential side effects.

Remodeling of repolarization and arrhythmia susceptibility in a myosin-binding protein C knockout mouse model.

Science.gov (United States)

Toib, Amir; Zhang, Chen; Borghetti, Giulia; Zhang, Xiaoxiao; Wallner, Markus; Yang, Yijun; Troupes, Constantine D; Kubo, Hajime; Sharp, Thomas E; Feldsott, Eric; Berretta, Remus M; Zalavadia, Neil; Trappanese, Danielle M; Harper, Shavonn; Gross, Polina; Chen, Xiongwen; Mohsin, Sadia; Houser, Steven R

2017-09-01

Hypertrophic cardiomyopathy (HCM) is one of the most common genetic cardiac diseases and among the leading causes of sudden cardiac death (SCD) in the young. The cellular mechanisms leading to SCD in HCM are not well known. Prolongation of the action potential (AP) duration (APD) is a common feature predisposing hypertrophied hearts to SCD. Previous studies have explored the roles of inward Na + and Ca 2+ in the development of HCM, but the role of repolarizing K + currents has not been defined. The objective of this study was to characterize the arrhythmogenic phenotype and cellular electrophysiological properties of mice with HCM, induced by myosin-binding protein C (MyBPC) knockout (KO), and to test the hypothesis that remodeling of repolarizing K + currents causes APD prolongation in MyBPC KO myocytes. We demonstrated that MyBPC KO mice developed severe hypertrophy and cardiac dysfunction compared with wild-type (WT) control mice. Telemetric electrocardiographic recordings of awake mice revealed prolongation of the corrected QT interval in the KO compared with WT control mice, with overt ventricular arrhythmias. Whole cell current- and voltage-clamp experiments comparing KO with WT mice demonstrated ventricular myocyte hypertrophy, AP prolongation, and decreased repolarizing K + currents. Quantitative RT-PCR analysis revealed decreased mRNA levels of several key K + channel subunits. In conclusion, decrease in repolarizing K + currents in MyBPC KO ventricular myocytes contributes to AP and corrected QT interval prolongation and could account for the arrhythmia susceptibility. NEW & NOTEWORTHY Ventricular myocytes isolated from the myosin-binding protein C knockout hypertrophic cardiomyopathy mouse model demonstrate decreased repolarizing K + currents and action potential and QT interval prolongation, linking cellular repolarization abnormalities with arrhythmia susceptibility and the risk for sudden cardiac death in hypertrophic cardiomyopathy. Copyright © 2017

Hereditary arrhythmias and cardiomyopathies: decision-making about genetic testing.

Science.gov (United States)

Louis, Clauden; Calamaro, Emily; Vinocur, Jeffrey M

2018-01-01

The modern field of clinical genetics has advanced beyond the traditional teachings familiar to most practicing cardiologists. Increased understanding of the roles of genetic testing may improve uptake and appropriateness of use. Clinical genetics has become integral to the management of patients with hereditary arrhythmia and cardiomyopathy diagnoses. Depending on the condition, genetic testing may be useful for diagnosis, prognosis, treatment, family screening, and reproductive planning. However, genetic testing is a powerful tool with potential for underuse, overuse, and misuse. In the absence of a substantial body of literature on how these guidelines are applied in clinical practice, we use a case-based approach to highlight key lessons and pitfalls. Importantly, in many scenarios genetic testing has become the standard of care supported by numerous class I recommendations; genetic counselors can improve accessibility to and appropriate use and application of testing. Optimal management of hereditary arrhythmias and cardiomyopathies incorporates genetic testing, applied as per consensus guidelines, with involvement of a multidisciplinary team.

Arctigenin, a potential anti-arrhythmic agent, inhibits aconitine-induced arrhythmia by regulating multi-ion channels.

Science.gov (United States)

Zhao, Zhenying; Yin, Yongqiang; Wu, Hong; Jiang, Min; Lou, Jianshi; Bai, Gang; Luo, Guo'an

2013-01-01

Arctigenin possesses biological activities, but its underlying mechanisms at the cellular and ion channel levels are not completely understood. Therefore, the present study was designed to identify the anti-arrhythmia effect of arctigenin in vivo, as well as its cellular targets and mechanisms. A rat arrhythmia model was established via continuous aconitine infusion, and the onset times of ventricular premature contraction, ventricular tachycardia and death were recorded. The Action Potential Duration (APD), sodium current (I(Na)), L-type calcium current (I(Ca, L)) and transient outward potassium current (I(to)) were measured and analysed using a patch-clamp recording technique in normal rat cardiomyocytes and myocytes of arrhythmia aconitine-induced by. Arctigenin significantly delayed the arrhythmia onset in the aconitine-induced rat model. The 50% and 90% repolarisations (APD50 and APD90) were shortened by 100 µM arctigenin; the arctigenin dose also inhibited the prolongation of APD50 and APD90 caused by 1 µM aconitine. Arctigenin inhibited I(Na) and I(Ca,L) and attenuated the aconitine-increased I(Na) and I(Ca,L) by accelerating the activation process and delaying the inactivation process. Arctigenin enhanced Ito by facilitating the activation process and delaying the inactivation process, and recoverd the decreased Ito induced by aconitine. Arctigenin has displayed anti-arrhythmia effects, both in vivo and in vitro. In the context of electrophysiology, I(Na), I(Ca, L), and I(to) may be multiple targets of arctigenin, leading to its antiarrhythmic effect. © 2013 S. Karger AG, Basel.

Possible influence of the polarity reversal of the solar magnetic field on the various types of arrhythmias

International Nuclear Information System (INIS)

Giannaropoulou, E; Papailiou, M; Mavromichalaki, H; Preka-Papadema, P; Gigolashvili, M; Tvildiani, L; Janashia, K; Papadima, Th

2013-01-01

Over the last few years various researches have reached the conclusion that cosmic ray variations and geomagnetic disturbances are related to the condition of the human physiological state. In this study medical data concerning the number of incidents of different types of cardiac arrhythmias for the time period 1983 – 1992 which refer to 1902 patients in Tbilisi, Georgia were used. The smoothing method and the Pearson r-coefficients were used to examine the possible effect of different solar and geomagnetic activity parameters and cosmic ray intensity variations on the different types of arrhythmias. The time interval under examination was separated into two different time periods which coincided with the polarity reversal of the solar magnetic field that occurred in the years 1989-1990 and as a result a different behavior of all the above mentioned parameters as well as of the different types of arrhythmias was noticed during the two time intervals. In addition, changing of polarity sign of the solar magnetic field was found to affect the sign of correlation between the incidence of arrhythmias and the aforementioned parameters. The primary and secondary maxima observed in the solar parameters during the solar cycle 22, also appeared in several types of arrhythmias with a time lag of about five months.

320-detector row CT coronary angiography in patients with arrhythmia

International Nuclear Information System (INIS)

Lu Li; Zhang Zhaoqi; Xu Lei; Yang Lin

2011-01-01

Objective: To evaluate the feasibility of CT coronary angiography (CTCA) in patients with arrhythmia using 320-detector row CT. Methods: Thirty-one patients with persistent atrial fibrillation and 8 patients with premature ventricular contraction were enrolled in this study. All patients underwent 320- detector row CTCA. CT image quality was evaluated with 4-point grading scale by two radiologists. Inter- observer agreement was evaluated by Kappa statistics. The radiation dose was calculated. Results: In total 510 coronary segments, 496 (97.2%) segments met diagnostic standard. The mean effective dose was (12.7±4.8) mSv in this study. There was a good agreement in image quality scoring between the two reviewers (Kappa = 0.72). Conclusion: 320-detector row CTCA is feasible in patients with atrial fibrillation and premature ventricular contraction. Arrhythmia may not be considered as a contraindication to CTCA. (authors)

Unique Association of Rare Cardiovascular Disease in an Athlete With Ventricular Arrhythmias.

Science.gov (United States)

Santomauro, V; Contursi, M; Dellegrottaglie, S; Borsellino, G

2015-01-01

Ventricular arrhythmias are a leading cause of non-elegibility to competitive sport. The failure to detect a significant organic substrate in the initial stage of screening does not preclude the identification of structural pathologies in the follow-up by using advanced imaging techniques. Here we report the case of a senior athlete judged not elegible because an arrhythmia with the morphology consistent with the origin of the left ventricle, in which subsequent execution of a cardiac MR and a thoracic CT scan has allowed the identification of an unique association between an area of myocardial damage, probable site of origine of the arrhythma, and a rare aortic malformation.

Investigation of energetic particle induced geodesic acoustic mode

Science.gov (United States)

Schneller, Mirjam; Fu, Guoyong; Chavdarovski, Ilija; Wang, Weixing; Lauber, Philipp; Lu, Zhixin

2017-10-01

Energetic particles are ubiquitous in present and future tokamaks due to heating systems and fusion reactions. Anisotropy in the distribution function of the energetic particle population is able to excite oscillations from the continuous spectrum of geodesic acoustic modes (GAMs), which cannot be driven by plasma pressure gradients due to their toroidally and nearly poloidally symmetric structures. These oscillations are known as energetic particle-induced geodesic acoustic modes (EGAMs) [G.Y. Fu'08] and have been observed in recent experiments [R. Nazikian'08]. EGAMs are particularly attractive in the framework of turbulence regulation, since they lead to an oscillatory radial electric shear which can potentially saturate the turbulence. For the presented work, the nonlinear gyrokinetic, electrostatic, particle-in-cell code GTS [W.X. Wang'06] has been extended to include an energetic particle population following either bump-on-tail Maxwellian or slowing-down [Stix'76] distribution function. With this new tool, we study growth rate, frequency and mode structure of the EGAM in an ASDEX Upgrade-like scenario. A detailed understanding of EGAM excitation reveals essential for future studies of EGAM interaction with micro-turbulence. Funded by the Max Planck Princeton Research Center. Computational resources of MPCDF and NERSC are greatefully acknowledged.

Design of a hybrid model for cardiac arrhythmia classification based on Daubechies wavelet transform.

Science.gov (United States)

Rajagopal, Rekha; Ranganathan, Vidhyapriya

2018-06-05

Automation in cardiac arrhythmia classification helps medical professionals make accurate decisions about the patient's health. The aim of this work was to design a hybrid classification model to classify cardiac arrhythmias. The design phase of the classification model comprises the following stages: preprocessing of the cardiac signal by eliminating detail coefficients that contain noise, feature extraction through Daubechies wavelet transform, and arrhythmia classification using a collaborative decision from the K nearest neighbor classifier (KNN) and a support vector machine (SVM). The proposed model is able to classify 5 arrhythmia classes as per the ANSI/AAMI EC57: 1998 classification standard. Level 1 of the proposed model involves classification using the KNN and the classifier is trained with examples from all classes. Level 2 involves classification using an SVM and is trained specifically to classify overlapped classes. The final classification of a test heartbeat pertaining to a particular class is done using the proposed KNN/SVM hybrid model. The experimental results demonstrated that the average sensitivity of the proposed model was 92.56%, the average specificity 99.35%, the average positive predictive value 98.13%, the average F-score 94.5%, and the average accuracy 99.78%. The results obtained using the proposed model were compared with the results of discriminant, tree, and KNN classifiers. The proposed model is able to achieve a high classification accuracy.

Perinatal management and long-term cardiac outcome in fetal arrhythmia

NARCIS (Netherlands)

Hahurij, N.D.; Blom, N.A.; Lopriore, E.; Aziz, M.I.; Nagel, H.T.; Rozendaal, L.; Vandenbussche, F.P.H.A.

2011-01-01

BACKGROUND: cardiac arrhythmias are commonly observed in the fetus, however, may have major consequences for fetal development and post natal life. AIMS: to evaluate the perinatal management and cardiac outcome of fetuses with tachy- or bradyarrhythmia. STUDY DESIGN: perinatal management, outcome

Privacy-Preserving Electrocardiogram Monitoring for Intelligent Arrhythmia Detection.

Science.gov (United States)

Son, Junggab; Park, Juyoung; Oh, Heekuck; Bhuiyan, Md Zakirul Alam; Hur, Junbeom; Kang, Kyungtae

2017-06-12

Long-term electrocardiogram (ECG) monitoring, as a representative application of cyber-physical systems, facilitates the early detection of arrhythmia. A considerable number of previous studies has explored monitoring techniques and the automated analysis of sensing data. However, ensuring patient privacy or confidentiality has not been a primary concern in ECG monitoring. First, we propose an intelligent heart monitoring system, which involves a patient-worn ECG sensor (e.g., a smartphone) and a remote monitoring station, as well as a decision support server that interconnects these components. The decision support server analyzes the heart activity, using the Pan-Tompkins algorithm to detect heartbeats and a decision tree to classify them. Our system protects sensing data and user privacy, which is an essential attribute of dependability, by adopting signal scrambling and anonymous identity schemes. We also employ a public key cryptosystem to enable secure communication between the entities. Simulations using data from the MIT-BIH arrhythmia database demonstrate that our system achieves a 95.74% success rate in heartbeat detection and almost a 96.63% accuracy in heartbeat classification, while successfully preserving privacy and securing communications among the involved entities.

Arctigenin, a Potential Anti-Arrhythmic Agent, Inhibits Aconitine-Induced Arrhythmia by Regulating Multi-Ion Channels

OpenAIRE

Zhenying Zhao; Yongqiang Yin; Hong Wu; Min Jiang; Jianshi Lou; Gang Bai; Guo‘an Luo

2013-01-01

Background/Aims: Arctigenin possesses biological activities, but its underlying mechanisms at the cellular and ion channel levels are not completely understood. Therefore, the present study was designed to identify the anti-arrhythmia effect of arctigenin in vivo, as well as its cellular targets and mechanisms. Methods: A rat arrhythmia model was established via continuous aconitine infusion, and the onset times of ventricular premature contraction, ventricular tachycardia and death were reco...

Features of conngestive heart failure development in patients with post infarct cardiosclerosis concomitant with arrhythmias

International Nuclear Information System (INIS)

Zharov, E.I.; Martynov, A.I.; Vertkin, A.L.; Sergeeva, L.I.; Sedov, V.P.

1989-01-01

Two hundred and seventy seven patients with coronary heart disease, includng 182 with postinfarction cardiosclerosis undewent 24-hour Holter monitoring. A significant correlation was found between the number of coupled ventricular arrhythmias, ventricular tachycardia paroxysms and developmet of congestive heart failure in patients with postinfarct cardiosclerosis. With evolving metabolic deficiency as evidenced by thallium-201 myocardial scintigraphy, the incidence of congestive heart failure and ventricular arrhythmias increased among the patients

Spiral Wave Initiation in Reaction-Diffusion-Mechanics Systems: A Model for the Onset of Reentrant Cardiac Arrhythmia

NARCIS (Netherlands)

Weise, L.D.

2012-01-01

Heart failure due to cardiac arrhythmias is a major cause of death in the industrialized world. Cardiac arrhythmia is often caused by spi- ral waves of electrical activity in the cardiac muscle. Therefore, it is a major task in cardiology to understand the mechanisms of spiral wave initiation in the

Noninvasive risk stratification of lethal ventricular arrhythmias and sudden cardiac death after myocardial infarction

Directory of Open Access Journals (Sweden)

Kenji Yodogawa, MD

2014-08-01

Full Text Available Prediction of lethal ventricular arrhythmias leading to sudden cardiac death is one of the most important and challenging problems after myocardial infarction (MI. Identification of MI patients who are prone to ventricular tachyarrhythmias allows for an indication of implantable cardioverter-defibrillator placement. To date, noninvasive techniques such as microvolt T-wave alternans (MTWA, signal-averaged electrocardiography (SAECG, heart rate variability (HRV, and heart rate turbulence (HRT have been developed for this purpose. MTWA is an indicator of repolarization abnormality and is currently the most promising risk-stratification tool for predicting malignant ventricular arrhythmias. Similarly, late potentials detected by SAECG are indices of depolarization abnormality and are useful in risk stratification. However, the role of SAECG is limited because of its low predictive accuracy. Abnormal HRV and HRT patterns reflect autonomic disturbances, which may increase the risk of lethal ventricular arrhythmias, but the existing evidence is insufficient. Further studies of noninvasive assessment may provide a new insight into risk stratification in post-MI patients.

Inflammation markers are associated with metabolic syndrome and ventricular arrhythmia in patients with coronary artery disease

Directory of Open Access Journals (Sweden)

Krzysztof Safranow

2016-02-01

Full Text Available Background: Inflammation plays a major role in the development and progression of atherosclerosis and coronary artery disease (CAD. Inflammation markers, including white blood cell (WBC count, C-reactive protein (CRP and interleukin-6 (IL-6, are widely used for cardiovascular risk prediction. The aim of the study was to establish factors associated with WBC, CRP and IL-6 in patients with CAD. Two functional polymorphisms in genes encoding enzymes participating in adenosine metabolism were analyzed (C34T AMPD1, G22A ADA. Methods: Plasma concentrations of IL-6 were measured using high-sensitivity ELISA kits, and the nephelometric method was used for high-sensitivity CRP (hs-CRP measurement in 167 CAD patients. Results: Presence of metabolic syndrome (MS and its components, presence of heart failure, severity of CAD symptoms, severe past ventricular arrhythmia (sustained ventricular tachycardia [sVT] or ventricular fibrillation [VF], lower left ventricle ejection fraction, higher left ventricle mass index, higher end-diastolic volume and higher number of smoking pack-years were significantly associated with higher WBC, CRP and IL-6. Strong associations with arrhythmia were observed for IL-6 (median 3.90 vs 1.89 pg/mL, p<0.00001 and CRP concentration (6.32 vs 1.47 mg/L, p=0.00009, while MS was associated most strongly with IL-6. CRP and IL-6 were independent markers discriminating patients with sVT or VF. There were no associations between AMPD1 or ADA genotypes and inflammation markers. Conclusions: WBC, CRP and IL-6 are strongly associated with components of the metabolic syndrome. Their strong association with life-threatening ventricular arrhythmia emphasizes the proarrhythmic role of inflammation in the increased cardiovascular risk of CAD patients.

TECRL, a new life-threatening inherited arrhythmia gene associated with overlapping clinical features of both LQTS and CPVT

NARCIS (Netherlands)

Devalla, Harsha D.; Gélinas, Roselle; Aburawi, Elhadi H.; Beqqali, Abdelaziz; Goyette, Philippe; Freund, Christian; Chaix, Marie-A.; Tadros, Rafik; Jiang, Hui; Le Béchec, Antony; Monshouwer-Kloots, Jantine J.; Zwetsloot, Tom; Kosmidis, Georgios; Latour, Frédéric; Alikashani, Azadeh; Hoekstra, Maaike; Schlaepfer, Jurg; Mummery, Christine L.; Stevenson, Brian; Kutalik, Zoltan; de Vries, Antoine Af; Rivard, Léna; Wilde, Arthur Am; Talajic, Mario; Verkerk, Arie O.; Al-Gazali, Lihadh; Rioux, John D.; Bhuiyan, Zahurul A.; Passier, Robert

2016-01-01

Genetic causes of many familial arrhythmia syndromes remain elusive. In this study, whole-exome sequencing (WES) was carried out on patients from three different families that presented with life-threatening arrhythmias and high risk of sudden cardiac death (SCD). Two French Canadian probands

Production of arrhythmias by elevated carboxyhemoglobin in patients with coronary artery disease

International Nuclear Information System (INIS)

Sheps, D.S.; Herbst, M.C.; Hinderliter, A.L.; Adams, K.F.; Ekelund, L.G.; O'Neil, J.J.; Goldstein, G.M.; Bromberg, P.A.; Dalton, J.L.; Ballenger, M.N.

1990-01-01

The object of this study was to assess the effects of exposure to 4% and 6% carboxyhemoglobin on ventricular arrhythmias in patients with coronary artery disease. This was a randomized, double-blind, crossover design. Forty-one nonsmokers with documented coronary artery disease were tested. On day 1, a training session with no exposure, the baseline carboxyhemoglobin level was measured, and a supine bicycle exercise test was done. On days 2 to 4, patients were exposed to room air, 100 ppm carbon monoxide (target, 4% carboxyhemoglobin) or 200 ppm carbon monoxide (target, 6% carboxyhemoglobin), and they then did supine bicycle exercise with radionuclide ventriculography. Ambulatory electrocardiogram recordings were made during the 4 consecutive days to determine the frequency of ventricular premature depolarization (VPD) at various intervals. The frequency of single VPD/h was significantly greater on the 6% carboxyhemoglobin day than on the room air day during the exercise period (167.72 +/- 37.99 for 6% carboxyhemoglobin compared with 127.32 +/- 28.22 for room air, P = 0.03). During exercise, the frequency of multiple VPD/h was greater on the 6% carboxyhemoglobin day compared with room air (9.59 +/- 3.70 on the 6% carboxyhemoglobin compared with 3.18 +/- 1.67 on room air, P = 0.02). Patients who developed increased single VPD during exercise on the 6% carboxyhemoglobin day were significantly older than those who had no increased arrhythmia, whereas patients who developed complex arrhythmias were also older and, in addition, exercised longer and had a higher peak workload during exercise. The number and complexity of ventricular arrhythmias increases significantly during exercise after carbon monoxide exposure producing 6% carboxyhemoglobin compared with room air but not after exposure producing 4% carboxyhemoglobin

Electrical initiation of an energetic nanolaminate film

Science.gov (United States)

Tringe, Joseph W.; Gash, Alexander E.; Barbee, Jr., Troy W.

2010-03-30

A heating apparatus comprising an energetic nanolaminate film that produces heat when initiated, a power source that provides an electric current, and a control that initiates the energetic nanolaminate film by directing the electric current to the energetic nanolaminate film and joule heating the energetic nanolaminate film to an initiation temperature. Also a method of heating comprising providing an energetic nanolaminate film that produces heat when initiated, and initiating the energetic nanolaminate film by directing an electric current to the energetic nanolaminate film and joule heating the energetic nanolaminate film to an initiation temperature.

Mortality of Inherited Arrhythmia Syndromes Insight Into Their Natural History

NARCIS (Netherlands)

Nannenberg, Eline A.; Sijbrands, Eric J. G.; Dijksman, Lea M.; Alders, Marielle; van Tintelen, J. Peter; Birnie, Martijn; van Langen, Irene M.; Wilde, Arthur A. M.

Background-For most arrhythmia syndromes, the risk of sudden cardiac death for asymptomatic mutation carriers is ill defined. Data on the natural history of these diseases, therefore, are essential. The family tree mortality ratio method offers the unique possibility to study the natural history at

An arrhythmia classification algorithm using a dedicated wavelet adapted to different subjects.

Science.gov (United States)

Kim, Jinkwon; Min, Se Dong; Lee, Myoungho

2011-06-27

Numerous studies have been conducted regarding a heartbeat classification algorithm over the past several decades. However, many algorithms have also been studied to acquire robust performance, as biosignals have a large amount of variation among individuals. Various methods have been proposed to reduce the differences coming from personal characteristics, but these expand the differences caused by arrhythmia. In this paper, an arrhythmia classification algorithm using a dedicated wavelet adapted to individual subjects is proposed. We reduced the performance variation using dedicated wavelets, as in the ECG morphologies of the subjects. The proposed algorithm utilizes morphological filtering and a continuous wavelet transform with a dedicated wavelet. A principal component analysis and linear discriminant analysis were utilized to compress the morphological data transformed by the dedicated wavelets. An extreme learning machine was used as a classifier in the proposed algorithm. A performance evaluation was conducted with the MIT-BIH arrhythmia database. The results showed a high sensitivity of 97.51%, specificity of 85.07%, accuracy of 97.94%, and a positive predictive value of 97.26%. The proposed algorithm achieves better accuracy than other state-of-the-art algorithms with no intrasubject between the training and evaluation datasets. And it significantly reduces the amount of intervention needed by physicians.

An arrhythmia classification algorithm using a dedicated wavelet adapted to different subjects

Directory of Open Access Journals (Sweden)

Min Se Dong

2011-06-01

Full Text Available Abstract Background Numerous studies have been conducted regarding a heartbeat classification algorithm over the past several decades. However, many algorithms have also been studied to acquire robust performance, as biosignals have a large amount of variation among individuals. Various methods have been proposed to reduce the differences coming from personal characteristics, but these expand the differences caused by arrhythmia. Methods In this paper, an arrhythmia classification algorithm using a dedicated wavelet adapted to individual subjects is proposed. We reduced the performance variation using dedicated wavelets, as in the ECG morphologies of the subjects. The proposed algorithm utilizes morphological filtering and a continuous wavelet transform with a dedicated wavelet. A principal component analysis and linear discriminant analysis were utilized to compress the morphological data transformed by the dedicated wavelets. An extreme learning machine was used as a classifier in the proposed algorithm. Results A performance evaluation was conducted with the MIT-BIH arrhythmia database. The results showed a high sensitivity of 97.51%, specificity of 85.07%, accuracy of 97.94%, and a positive predictive value of 97.26%. Conclusions The proposed algorithm achieves better accuracy than other state-of-the-art algorithms with no intrasubject between the training and evaluation datasets. And it significantly reduces the amount of intervention needed by physicians.

Chewing reduces sympathetic nervous response to stress and prevents poststress arrhythmias in rats.

Science.gov (United States)

Koizumi, So; Minamisawa, Susumu; Sasaguri, Kenichi; Onozuka, Minoru; Sato, Sadao; Ono, Yumie

2011-10-01

Reducing stress is important in preventing sudden death in patients with cardiovascular disease, as stressful events may cause autonomic imbalance and trigger fatal arrhythmias. Since chewing has been shown to inhibit stress-induced neuronal responses in the hypothalamus, we hypothesized that chewing could ameliorate stress-induced autonomic imbalance and prevent arrhythmias. To test this hypothesis, we analyzed changes in radiotelemetered electrocardiograms in rats that were allowed to chew a wooden stick during a 1-h period of immobilization stress. Chewing significantly reduced the occurrence of ventricular premature beats (VPBs) and complex ventricular ectopy after immobilization and prevented stress-induced prolongation of the QT interval of VPBs throughout the 10-h experimental period. It also prevented prolongation of the QRS complex and fluctuations in the QT interval in normal sinus rhythm beats preceding VPBs during both immobilization and in the poststress period. Fast Fourier transform-based spectral analysis of heart-rate variability further showed that chewing significantly inhibited the stress-induced increase in the power ratio of low-to-high frequency activity (LF/HF: a marker of sympathetic activity) during immobilization and in addition was associated with blunting of the stress-induced increase in plasma noradrenaline observed at the termination of immobilization. Similar suppressive effects on the occurrence of VPBs and the LF/HF were observed in rats that were administered the β-adrenergic blocker propranolol before immobilization. These results indicate that chewing can ameliorate sympathetic hyperactivity during stress and prevent poststress arrhythmias and suggest that chewing may provide a nonpharmacological and cost-effective treatment option for patients with a high risk of stress-induced fatal arrhythmia.

Arrhythmia Classification Based on Multi-Domain Feature Extraction for an ECG Recognition System

Directory of Open Access Journals (Sweden)

Hongqiang Li

2016-10-01

Full Text Available Automatic recognition of arrhythmias is particularly important in the diagnosis of heart diseases. This study presents an electrocardiogram (ECG recognition system based on multi-domain feature extraction to classify ECG beats. An improved wavelet threshold method for ECG signal pre-processing is applied to remove noise interference. A novel multi-domain feature extraction method is proposed; this method employs kernel-independent component analysis in nonlinear feature extraction and uses discrete wavelet transform to extract frequency domain features. The proposed system utilises a support vector machine classifier optimized with a genetic algorithm to recognize different types of heartbeats. An ECG acquisition experimental platform, in which ECG beats are collected as ECG data for classification, is constructed to demonstrate the effectiveness of the system in ECG beat classification. The presented system, when applied to the MIT-BIH arrhythmia database, achieves a high classification accuracy of 98.8%. Experimental results based on the ECG acquisition experimental platform show that the system obtains a satisfactory classification accuracy of 97.3% and is able to classify ECG beats efficiently for the automatic identification of cardiac arrhythmias.

Use of whole exome sequencing for the identification of Ito-based arrhythmia mechanism and therapy.

Science.gov (United States)

Sturm, Amy C; Kline, Crystal F; Glynn, Patric; Johnson, Benjamin L; Curran, Jerry; Kilic, Ahmet; Higgins, Robert S D; Binkley, Philip F; Janssen, Paul M L; Weiss, Raul; Raman, Subha V; Fowler, Steven J; Priori, Silvia G; Hund, Thomas J; Carnes, Cynthia A; Mohler, Peter J

2015-05-26

Identified genetic variants are insufficient to explain all cases of inherited arrhythmia. We tested whether the integration of whole exome sequencing with well-established clinical, translational, and basic science platforms could provide rapid and novel insight into human arrhythmia pathophysiology and disease treatment. We report a proband with recurrent ventricular fibrillation, resistant to standard therapeutic interventions. Using whole-exome sequencing, we identified a variant in a previously unidentified exon of the dipeptidyl aminopeptidase-like protein-6 (DPP6) gene. This variant is the first identified coding mutation in DPP6 and augments cardiac repolarizing current (Ito) causing pathological changes in Ito and action potential morphology. We designed a therapeutic regimen incorporating dalfampridine to target Ito. Dalfampridine, approved for multiple sclerosis, normalized the ECG and reduced arrhythmia burden in the proband by >90-fold. This was combined with cilostazol to accelerate the heart rate to minimize the reverse-rate dependence of augmented Ito. We describe a novel arrhythmia mechanism and therapeutic approach to ameliorate the disease. Specifically, we identify the first coding variant of DPP6 in human ventricular fibrillation. These findings illustrate the power of genetic approaches for the elucidation and treatment of disease when carefully integrated with clinical and basic/translational research teams. © 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Frequency of cardiac arrhythmias in high and low- yielding dairy cows

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Afshin Jafari Dehkordi

2014-06-01

Full Text Available Electrocardiography (ECG may be used to recognize cardiac disorders. Levels of milk production may change the serum electrolytes which its imbalance has a role in cardiac arrhythmia. Fifty high yielding and fifty low yielding Holstein dairy cows were used in this study. Electrocardiography was recorded by base-apex lead and blood samples were collected from jugular vein for measurement of serum elements such as sodium, potassium, calcium, phosphorous, iron and magnesium. Cardiac dysrhythmias were detected more frequent in low yielding Holstein cows (62.00% compared to high yielding Holstein cows (46.00%. The cardiac dysrhythmias that were observed in low yielding Holstein cows included sinus arrhythmia (34.70%, wandering pacemaker (22.45 %, bradycardia (18.37%, tachycardia (10.20%, atrial premature beat (2.04%, sinoatrial block (2.04%, atrial fibrillation (8.16% and atrial tachycardia (2.04%. The cardiac dysrhythmias were observed in high yielding Holstein cows including, sinus arrhythmia (86.95% and wandering pacemaker (13.05%. Also, notched P wave was observed to be 30% and 14% in high- and low- yielding Holstein cows respectively. The serum calcium concentration of low yielding Holstein cows was significantly lower than that of high yielding Holstein cows. There was not any detectable significant difference in other serum elements between high- and low- yielding Holstein cows. Based on the result of present study, could be concluded that low serum concentration of calcium results to more frequent dysrhythmias in low yielding Holstein cows.

About Russian nuclear energetic perspectives

International Nuclear Information System (INIS)

Laletin, N.I.

2003-01-01

My particular view about Russian nuclear energetics perspectives is presented. The nearest and the further perspectives are considered. The arguments are adduced that the most probable scenario of nuclear energetic development is its stabilization in the near future. Fur further development the arguments of supporters and opponents of nuclear energetics are analyzed. Three points of view are considered. The first point of view that there is not alternative for nuclear energetics. My notes are the following ones. a) I express a skeptic opinion about a statement of quick exhaustion of fossil organic fuel recourses and corresponding estimations are presented. b) It is expressed skeptic opinion about the statement that nuclear energetics can have a visual influence on ''steam effect''. c) I agree that nuclear energetics is the most ecological technology for normal work but however we can't disregard possibilities of catastrophic accidents. The second point of view that the use of nuclear energetics can't have the justification. I adduce the arguments contrary to this statement. The third point of view that nuclear energetics is a usual technology and the only criteria for discussions about what dimension and where one ought develop it is total cost of its unit. Expressed an opinion that the deceived for the choose of a way the skill of the estimate correctly and optimized so named the external parts of the unit energy costs for different energy technologies. (author)

Radiofrequency catheter ablation in the treatment of cardiac arrhythmias (first of two parts)

International Nuclear Information System (INIS)

Kou, W.H; Morady, F.

1997-01-01

The intravenous radiofrequency catheter inside cardiac s chambers, for inspect signals intracardiac s and to encourage, has been developed as diagnostic tool with the purpose to search arrhythmias physiology and physiopathology.Many energy sources has been used: direct energy, radiofrequency 11-15, laser 6,17, and microwave 18,19. A comparison between radiofrequency and electric energy shock has been described in cardiac arrhythmias treatment, in the present article. It has been tested the radiation biological effects and risk in Wolff Parkinson White patients as well as doctors who handling the fluoroscopy for image during the radiofrequency ablation. Has been described the following techniques: Catheter ablation radiofrequency slow way and fast way

The Role of Biologically Active Ingredients from Natural Drug Treatments for Arrhythmias in Different Mechanisms

OpenAIRE

Li, Jie; Hu, Dan; Song, Xiaoli; Han, Tao; Gao, Yonghong; Xing, Yanwei

2017-01-01

Arrhythmia is a disease that is caused by abnormal electrical activity in the heart rate or rhythm. It is the major cause of cardiovascular morbidity and mortality. Although several antiarrhythmic drugs have been used in clinic for decades, their application is often limited by their adverse effects. As a result, natural drugs, which have fewer side effects, are now being used to treat arrhythmias. We searched for all articles on the role of biologically active ingredients from natural drug t...

Combined effects of space charge and energetic disorder on photocurrent efficiency loss of field-dependent organic photovoltaic devices

International Nuclear Information System (INIS)

Yoon, Sangcheol; Hwang, Inchan; Park, Byoungchoo

2015-01-01

The loss of photocurrent efficiency by space-charge effects in organic solar cells with energetic disorder was investigated to account for how energetic disorder incorporates space-charge effects, utilizing a drift-diffusion model with field-dependent charge-pair dissociation and suppressed bimolecular recombination. Energetic disorder, which induces the Poole–Frenkel behavior of charge carrier mobility, is known to decrease the mobility of charge carriers and thus reduces photovoltaic performance. We found that even if the mobilities are the same in the absence of space-charge effects, the degree of energetic disorder can be an additional parameter affecting photocurrent efficiency when space-charge effects occur. Introducing the field-dependence parameter that reflects the energetic disorder, the behavior of efficiency loss with energetic disorder can differ depending on which charge carrier is subject to energetic disorder. While the energetic disorder that is applied to higher-mobility charge carriers decreases photocurrent efficiency further, the efficiency loss can be suppressed when energetic disorder is applied to lower-mobility charge carriers. (paper)

Single-Nucleotide Variations in Cardiac Arrhythmias: Prospects for Genomics and Proteomics Based Biomarker Discovery and Diagnostics

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Ayman Abunimer

2014-03-01

Full Text Available Cardiovascular diseases are a large contributor to causes of early death in developed countries. Some of these conditions, such as sudden cardiac death and atrial fibrillation, stem from arrhythmias—a spectrum of conditions with abnormal electrical activity in the heart. Genome-wide association studies can identify single nucleotide variations (SNVs that may predispose individuals to developing acquired forms of arrhythmias. Through manual curation of published genome-wide association studies, we have collected a comprehensive list of 75 SNVs associated with cardiac arrhythmias. Ten of the SNVs result in amino acid changes and can be used in proteomic-based detection methods. In an effort to identify additional non-synonymous mutations that affect the proteome, we analyzed the post-translational modification S-nitrosylation, which is known to affect cardiac arrhythmias. We identified loss of seven known S-nitrosylation sites due to non-synonymous single nucleotide variations (nsSNVs. For predicted nitrosylation sites we found 1429 proteins where the sites are modified due to nsSNV. Analysis of the predicted S-nitrosylation dataset for over- or under-representation (compared to the complete human proteome of pathways and functional elements shows significant statistical over-representation of the blood coagulation pathway. Gene Ontology (GO analysis displays statistically over-represented terms related to muscle contraction, receptor activity, motor activity, cystoskeleton components, and microtubule activity. Through the genomic and proteomic context of SNVs and S-nitrosylation sites presented in this study, researchers can look for variation that can predispose individuals to cardiac arrhythmias. Such attempts to elucidate mechanisms of arrhythmia thereby add yet another useful parameter in predicting susceptibility for cardiac diseases.

Observation of enhanced radial transport of energetic ion due to energetic particle mode destabilized by helically-trapped energetic ion in the Large Helical Device

Science.gov (United States)

Ogawa, K.; Isobe, M.; Kawase, H.; Nishitani, T.; Seki, R.; Osakabe, M.; LHD Experiment Group

2018-04-01

A deuterium experiment was initiated to achieve higher-temperature and higher-density plasmas in March 2017 in the Large Helical Device (LHD). The central ion temperature notably increases compared with that in hydrogen experiments. However, an energetic particle mode called the helically-trapped energetic-ion-driven resistive interchange (EIC) mode is often excited by intensive perpendicular neutral beam injections on high ion-temperature discharges. The mode leads to significant decrease of the ion temperature or to limiting the sustainment of the high ion-temperature state. To understand the effect of EIC on the energetic ion confinement, the radial transport of energetic ions is studied by means of the neutron flux monitor and vertical neutron camera newly installed on the LHD. Decreases of the line-integrated neutron profile in core channels show that helically-trapped energetic ions are lost from the plasma.

Analysis of the energetic sector through the national energetic matrix

International Nuclear Information System (INIS)

Garzon Lozano, Enrique

2007-01-01

The author shows the results of the national energetic balance 1975-2005, through the energetic matrix of the country, giving an annual growth of 5.1% in this period of offer of primary energy, where the mineral coal participates with 9,6%, the hydraulic energy with 4,8%, natural gas with 4,2%, trash with 2,4% and petroleum with 2,2%, while the firewood fell in 0,5%

Cardiac arrhythmia beat classification using DOST and PSO tuned SVM.

Science.gov (United States)

Raj, Sandeep; Ray, Kailash Chandra; Shankar, Om

2016-11-01

The increase in the number of deaths due to cardiovascular diseases (CVDs) has gained significant attention from the study of electrocardiogram (ECG) signals. These ECG signals are studied by the experienced cardiologist for accurate and proper diagnosis, but it becomes difficult and time-consuming for long-term recordings. Various signal processing techniques are studied to analyze the ECG signal, but they bear limitations due to the non-stationary behavior of ECG signals. Hence, this study aims to improve the classification accuracy rate and provide an automated diagnostic solution for the detection of cardiac arrhythmias. The proposed methodology consists of four stages, i.e. filtering, R-peak detection, feature extraction and classification stages. In this study, Wavelet based approach is used to filter the raw ECG signal, whereas Pan-Tompkins algorithm is used for detecting the R-peak inside the ECG signal. In the feature extraction stage, discrete orthogonal Stockwell transform (DOST) approach is presented for an efficient time-frequency representation (i.e. morphological descriptors) of a time domain signal and retains the absolute phase information to distinguish the various non-stationary behavior ECG signals. Moreover, these morphological descriptors are further reduced in lower dimensional space by using principal component analysis and combined with the dynamic features (i.e based on RR-interval of the ECG signals) of the input signal. This combination of two different kinds of descriptors represents each feature set of an input signal that is utilized for classification into subsequent categories by employing PSO tuned support vector machines (SVM). The proposed methodology is validated on the baseline MIT-BIH arrhythmia database and evaluated under two assessment schemes, yielding an improved overall accuracy of 99.18% for sixteen classes in the category-based and 89.10% for five classes (mapped according to AAMI standard) in the patient

Comparison of real-time classification systems for arrhythmia detection on Android-based mobile devices.

Science.gov (United States)

Leutheuser, Heike; Gradl, Stefan; Kugler, Patrick; Anneken, Lars; Arnold, Martin; Achenbach, Stephan; Eskofier, Bjoern M

2014-01-01

The electrocardiogram (ECG) is a key diagnostic tool in heart disease and may serve to detect ischemia, arrhythmias, and other conditions. Automatic, low cost monitoring of the ECG signal could be used to provide instantaneous analysis in case of symptoms and may trigger the presentation to the emergency department. Currently, since mobile devices (smartphones, tablets) are an integral part of daily life, they could form an ideal basis for automatic and low cost monitoring solution of the ECG signal. In this work, we aim for a realtime classification system for arrhythmia detection that is able to run on Android-based mobile devices. Our analysis is based on 70% of the MIT-BIH Arrhythmia and on 70% of the MIT-BIH Supraventricular Arrhythmia databases. The remaining 30% are reserved for the final evaluation. We detected the R-peaks with a QRS detection algorithm and based on the detected R-peaks, we calculated 16 features (statistical, heartbeat, and template-based). With these features and four different feature subsets we trained 8 classifiers using the Embedded Classification Software Toolbox (ECST) and compared the computational costs for each classification decision and the memory demand for each classifier. We conclude that the C4.5 classifier is best for our two-class classification problem (distinction of normal and abnormal heartbeats) with an accuracy of 91.6%. This classifier still needs a detailed feature selection evaluation. Our next steps are implementing the C4.5 classifier for Android-based mobile devices and evaluating the final system using the remaining 30% of the two used databases.

Monitoring of arrhythmia and sudden death in a hemodialysis population: The CRASH-ILR Study.

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Paul R Roberts

Full Text Available It has been suggested that sudden cardiac death (SCD contributes around 50% of cardiovascular and 27% of all-cause mortality in hemodialysis patients. The true burden of arrhythmias and arrhythmic deaths in this population, however, remains poorly characterised. Cardio Renal Arrhythmia Study in Hemodialysis (CRASH-ILR is a prospective, implantable loop recorder single centre study of 30 established hemodialysis patients and one of the first to provide long-term ambulatory ECG monitoring.30 patients (60% male aged 68±12 years receiving hemodialysis for 45±40 months with varied etiology (diabetes 37%, hypertension 23% and left ventricular ejection fraction (LVEF 55±8% received a Reveal XT implantable loop recorder (Medtronic, USA between August 2011 and October 2014. ECG data from loop recorders were transmitted at each hemodialysis session using a remote monitoring system. Primary outcome was SCD or implantation of a (tachy or bradyarrhythmia controlling device and secondary outcome, the development of arrhythmia necessitating medical intervention.During 379,512 hours of continuous ECG monitoring (mean 12,648±9,024 hours/patient, there were 8 deaths-2 SCD and 6 due to generalised deterioration/sepsis. 5 (20% patients had a primary outcome event (2 SCD, 3 pacemaker implantations for bradyarrhythmia. 10 (33% patients reached an arrhythmic primary or secondary end point. Median event free survival for any arrhythmia was 2.6 years (95% confidence intervals 1.6-3.6 years.The findings confirm the high mortality rate seen in hemodialysis populations and contrary to initial expectations, bradyarrhythmias emerged as a common and potentially significant arrhythmic event.

Temporally distinct response of irradiated normal human fibroblasts and their bystander cells to energetic heavy ions

International Nuclear Information System (INIS)

Hamada, Nobuyuki; Ni, Meinan; Funayama, Tomoo; Sakashita, Tetsuya; Kobayashi, Yasuhiko

2008-01-01

Ionizing radiation-induced bystander effects have been documented for a multitude of endpoints such as mutations, chromosome aberrations and cell death, which arise in nonirradiated bystander cells having received signals from directly irradiated cells; however, energetic heavy ion-induced bystander response is incompletely characterized. To address this, we employed precise microbeams of carbon and neon ions for targeting only a very small fraction of cells in confluent fibroblast cultures. Conventional broadfield irradiation was conducted in parallel to see the effects in irradiated cells. Exposure of 0.00026% of cells led to nearly 10% reductions in the clonogenic survival and twofold rises in the apoptotic incidence regardless of ion species. Whilst apoptotic frequency increased with time up to 72 h postirradiation in irradiated cells, its frequency escalated up to 24 h postirradiation but declined at 48 h postirradiation in bystander cells, indicating that bystander cells exhibit transient commitment to apoptosis. Carbon- and neon-ion microbeam irradiation similarly caused almost twofold increments in the levels of serine 15-phosphorylated p53 proteins, irrespective of whether 0.00026, 0.0013 or 0.0066% of cells were targeted. Whereas the levels of phosphorylated p53 were elevated and remained unchanged at 2 h and 6 h postirradiation in irradiated cells, its levels rose at 6 h postirradiation but not at 2 h postirradiation in bystander cells, suggesting that bystander cells manifest delayed p53 phosphorylation. Collectively, our results indicate that heavy ions inactivate clonogenic potential of bystander cells, and that the time course of the response to heavy ions differs between irradiated and bystander cells. These induced bystander responses could be a defensive mechanism that minimizes further expansion of aberrant cells

Privacy-Preserving Electrocardiogram Monitoring for Intelligent Arrhythmia Detection †

Science.gov (United States)

Son, Junggab; Park, Juyoung; Oh, Heekuck; Bhuiyan, Md Zakirul Alam; Hur, Junbeom; Kang, Kyungtae

2017-01-01

Long-term electrocardiogram (ECG) monitoring, as a representative application of cyber-physical systems, facilitates the early detection of arrhythmia. A considerable number of previous studies has explored monitoring techniques and the automated analysis of sensing data. However, ensuring patient privacy or confidentiality has not been a primary concern in ECG monitoring. First, we propose an intelligent heart monitoring system, which involves a patient-worn ECG sensor (e.g., a smartphone) and a remote monitoring station, as well as a decision support server that interconnects these components. The decision support server analyzes the heart activity, using the Pan–Tompkins algorithm to detect heartbeats and a decision tree to classify them. Our system protects sensing data and user privacy, which is an essential attribute of dependability, by adopting signal scrambling and anonymous identity schemes. We also employ a public key cryptosystem to enable secure communication between the entities. Simulations using data from the MIT-BIH arrhythmia database demonstrate that our system achieves a 95.74% success rate in heartbeat detection and almost a 96.63% accuracy in heartbeat classification, while successfully preserving privacy and securing communications among the involved entities. PMID:28604628

Arrhythmia as a cardiac manifestation in MELAS syndrome.

Science.gov (United States)

Thomas, Tamara; Craigen, William J; Moore, Ryan; Czosek, Richard; Jefferies, John L

2015-09-01

A 44-year-old female with a diagnosis of mitochondrial myopathy, encephalopathy and stroke-like episodes (MELAS) syndrome had progressive left ventricular hypertrophy (LVH) on echocardiogram. A Holter monitor demonstrated episodes of non-sustained atrial tachycardia, a finding not been previously described in this population. This unique case of MELAS syndrome demonstrates the known associated cardiac manifestation of LVH and the new finding of atrial tachycardia which may represent the potential for subclinical arrhythmia in this population.

Relationship of serum magnesium level and supplemental magnesium dosage with post coronary artery bypass graft surgery arrhythmias

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Najafi M

2007-06-01

Full Text Available Background: Atrial and ventricular arrhythmias are among the most common complications after coronary artery bypass graft (CABG surgery. Previous studies demonstrated that cardiopulmonary bypass itself results in reduced serum magnesium levels. In this study, we evaluated the effect of total blood magnesium level (TMG on the prevention of perioperative arrhythmias with routine regimens of 2-4 grams supplemental magnesium (SMG. Methods: TMG was measured in patients who were scheduled for CABG on three occasions: just before anesthesia, just after entering the intensive care unit (ICU after completion of the sugery, and on the first morning after the operation. Patients were evaluated for primary cardiac rhythm and other variables that could have an influence on the magnesium level, including serum creatinine, urine output in the operating room and diuretic therapy. The SMG dosage was also recorded in the operating room and ICU. Patients were then evaluated for the rate and type of arrhythmia for the next three days. Results: The mean TMG levels in 174 cases were 2.2 (0.5, 2.6 (0.6 and 2.4 (0.6 mg/dl for the three occasions, respectively. The mean SMG was 2.5 (1.2 grams. Of 164 patients, 51 (31% developed the following post-operative arrhythmias: AF (7.3%, non-AF SVA (15.2% and ventricular (16.5%. The mean serum creatinine level and urine output were 1.2 mg/dl and 1800 ml, respectively. Although there was a significant difference between the TMG levels on the three different occasions (P<0.001, all values were within normal range. When we stratified the TMG levels of the patients based on administered SMG, the Mentel-Haenszel test revealed no significant difference between the first and third TMG (P=0.6. Although the TMG levels were higher in arrhythmic patients compared to those without arrhythmia (2.25 vs. 2.14 mg/dl, both values were within the normal range and there was no significant difference between the two groups. Serum creatinine levels

Flare energetics

Science.gov (United States)

Wu, S. T.; Dejager, C.; Dennis, B. R.; Hudson, H. S.; Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.; Bruner, M. E.; Cargill, P. J.

1986-01-01

In this investigation of flare energetics, researchers sought to establish a comprehensive and self-consistent picture of the sources and transport of energy within a flare. To achieve this goal, they chose five flares in 1980 that were well observed with instruments on the Solar Maximum Mission, and with other space-borne and ground-based instruments. The events were chosen to represent various types of flares. Details of the observations available for them and the corresponding physical parameters derived from these data are presented. The flares were studied from two perspectives, the impulsive and gradual phases, and then the results were compared to obtain the overall picture of the energics of these flares. The role that modeling can play in estimating the total energy of a flare when the observationally determined parameters are used as the input to a numerical model is discussed. Finally, a critique of the current understanding of flare energetics and the methods used to determine various energetics terms is outlined, and possible future directions of research in this area are suggested.

Classification of ECG signal with Support Vector Machine Method for Arrhythmia Detection

Science.gov (United States)

Turnip, Arjon; Ilham Rizqywan, M.; Kusumandari, Dwi E.; Turnip, Mardi; Sihombing, Poltak

2018-03-01

An electrocardiogram is a potential bioelectric record that occurs as a result of cardiac activity. QRS Detection with zero crossing calculation is one method that can precisely determine peak R of QRS wave as part of arrhythmia detection. In this paper, two experimental scheme (2 minutes duration with different activities: relaxed and, typing) were conducted. From the two experiments it were obtained: accuracy, sensitivity, and positive predictivity about 100% each for the first experiment and about 79%, 93%, 83% for the second experiment, respectively. Furthermore, the feature set of MIT-BIH arrhythmia using the support vector machine (SVM) method on the WEKA software is evaluated. By combining the available attributes on the WEKA algorithm, the result is constant since all classes of SVM goes to the normal class with average 88.49% accuracy.

The effect of intermittent fasting and water restriction on myocardial ischemia/reperfusion-induced arrhythmia in rats

OpenAIRE

KAYA, Salih Tunç; BOZDOĞAN, Ömer

2011-01-01

To investigate the effect of intermittent fasting and water restriction on ischemia/reperfusion-induced arrhythmias. Materials and methods: Six minutes of ischemia followed by 6 min of reperfusion was produced by the ligation and then releasing of the left coronary artery. Intermittent fasting and water restriction were applied during 1 month for 12 h/day. The duration, type, and incidence of arrhythmias during reperfusion and the survival rate at the end of reperfusion were determined and c...

LiteNet: Lightweight Neural Network for Detecting Arrhythmias at Resource-Constrained Mobile Devices

Directory of Open Access Journals (Sweden)

Ziyang He

2018-04-01

Full Text Available By running applications and services closer to the user, edge processing provides many advantages, such as short response time and reduced network traffic. Deep-learning based algorithms provide significantly better performances than traditional algorithms in many fields but demand more resources, such as higher computational power and more memory. Hence, designing deep learning algorithms that are more suitable for resource-constrained mobile devices is vital. In this paper, we build a lightweight neural network, termed LiteNet which uses a deep learning algorithm design to diagnose arrhythmias, as an example to show how we design deep learning schemes for resource-constrained mobile devices. Compare to other deep learning models with an equivalent accuracy, LiteNet has several advantages. It requires less memory, incurs lower computational cost, and is more feasible for deployment on resource-constrained mobile devices. It can be trained faster than other neural network algorithms and requires less communication across different processing units during distributed training. It uses filters of heterogeneous size in a convolutional layer, which contributes to the generation of various feature maps. The algorithm was tested using the MIT-BIH electrocardiogram (ECG arrhythmia database; the results showed that LiteNet outperforms comparable schemes in diagnosing arrhythmias, and in its feasibility for use at the mobile devices.

Obesity and exercise-induced ectopic ventricular arrhythmias in apparently healthy middle aged adults.

Science.gov (United States)

Sabbag, Avi; Sidi, Yechezkel; Kivity, Shaye; Beinart, Roy; Glikson, Michael; Segev, Shlomo; Goldenberg, Ilan; Maor, Elad

2016-03-01

Obesity and overweight are strongly associated with cardiovascular morbidity and mortality. However, there are limited data on the association between excess weight and the risk of ectopic ventricular activity. We investigated the association between body mass index (BMI) and the risk for ectopic ventricular activity (defined as multiple ventricular premature beats (≥3), ventricular bigeminy, nonsustained ventricular tachycardia or sustained ventricular tachycardia) during exercise stress testing among 22,516 apparently healthy men and women who attended periodic health screening examinations between the years 2000 and 2014. All subjects had completed maximal exercise stress testing annually according to the Bruce protocol. Subjects were divided at baseline into three groups: normal weight (BMI ≥ 18.5 kg/m(2) andexercise-induced ectopic ventricular activity arrhythmias was highest among obese subjects, intermediate among overweight subjects and lowest among subjects with normal weight (3.4%, 2.7% and 2.2% respectively; p exercise compared with subjects with normal weight (p = 0.005), and that each 1 kg/m(2) increase in BMI was associated with a significant 4% (p = 0.002) increased adjusted risk for exercise-induced ventricular arrhythmias. Obesity is independently associated with increased likelihood of ectopic ventricular arrhythmia during exercise. © The European Society of Cardiology 2015.

LiteNet: Lightweight Neural Network for Detecting Arrhythmias at Resource-Constrained Mobile Devices.

Science.gov (United States)

He, Ziyang; Zhang, Xiaoqing; Cao, Yangjie; Liu, Zhi; Zhang, Bo; Wang, Xiaoyan

2018-04-17

By running applications and services closer to the user, edge processing provides many advantages, such as short response time and reduced network traffic. Deep-learning based algorithms provide significantly better performances than traditional algorithms in many fields but demand more resources, such as higher computational power and more memory. Hence, designing deep learning algorithms that are more suitable for resource-constrained mobile devices is vital. In this paper, we build a lightweight neural network, termed LiteNet which uses a deep learning algorithm design to diagnose arrhythmias, as an example to show how we design deep learning schemes for resource-constrained mobile devices. Compare to other deep learning models with an equivalent accuracy, LiteNet has several advantages. It requires less memory, incurs lower computational cost, and is more feasible for deployment on resource-constrained mobile devices. It can be trained faster than other neural network algorithms and requires less communication across different processing units during distributed training. It uses filters of heterogeneous size in a convolutional layer, which contributes to the generation of various feature maps. The algorithm was tested using the MIT-BIH electrocardiogram (ECG) arrhythmia database; the results showed that LiteNet outperforms comparable schemes in diagnosing arrhythmias, and in its feasibility for use at the mobile devices.

Dispersion of repolarization and refractoriness are determinants of arrhythmia phenotype in transgenic mice with long QT.

Science.gov (United States)

London, Barry; Baker, Linda C; Petkova-Kirova, Polina; Nerbonne, Jeanne M; Choi, Bum-Rak; Salama, Guy

2007-01-01

Enhanced dispersion of repolarization (DR) and refractoriness may be a unifying mechanism central to arrhythmia genesis in the long QT (LQT) syndrome. The role of DR in promoting arrhythmias was investigated in several strains of molecularly engineered mice: (a) Kv4.2 dominant negative transgenic (Kv4.2DN) that lacks the fast component of the transient outward current, I(to,f), have action potential (AP) and QT prolongation, but no spontaneous arrhythmias, (b) Kv1.4 targeted mice (Kv1.4-/-) that lack the slow component of I(to) (I(to,s)), have no QT prolongation and no spontaneous arrhythmias, and (c) double transgenic (Kv4.2DN x Kv1.4-/-) mice that lack both I(to,f) and I(to,s), have AP and QT prolongation, and spontaneous ventricular tachyarrhythmias. Hearts were perfused, stained with di-4-ANEPPS and optically mapped. Activation patterns and conduction velocities were similar between the strains but AP duration at 75% recovery (APD75) was longer in Kv4.2DN (28.0 +/- 2.5 ms, P mice than controls (20.3 +/- 1.0 ms, n = 5). Dispersion of refractoriness between apex and base was markedly reduced in Kv4.2DN (0.3 +/- 0.5 ms, n = 6, P mice compared with controls (10 +/- 2 ms, n = 5). A premature pulse elicited ventricular tachycardia (VT) in Kv1.4-/- (n = 4/5) and Kv4.2DN x Kv1.4-/- hearts (n = 5/5) but not Kv4.2DN hearts (n = 0/6). Voltage-clamp recordings showed that I(to,f) was 30% greater in myocytes from the apex than base which may account for the absence of DR in Kv4.2DN mice. Thus, dispersion of repolarization (DR) appears to be an important determinant of arrhythmia vulnerability.

An extended family suddenly confronted with a life-threatening hereditary arrhythmia

NARCIS (Netherlands)

Hendriks, K.S.W.H.; Van Langen, I.M.; Van Tintelen, J.P.; Grosfeld, F.J.M.; Wilde, A.A.M.; Ten Kroode, H.F.J.

2005-01-01

Objective. This exploratory study serves to illustrate the psychological impact on an extended family in the process of genetic counselling and testing for a potentially life-threatening arrhythmia, the long-QT syndrome (LQTS). Method. All members of the third generation and their partners (n=11)

Cardiovascular exercise and burden of arrhythmia in patients with atrial fibrillation

DEFF Research Database (Denmark)

Skielboe, Ane Katrine; Bandholm, Thomas Quaade; Hakmann, Stine

2017-01-01

BACKGROUND: Physical activity at moderate-high intensity is recommended to prevent lifestyle diseases. Patients with atrial fibrillation are at risk of a sedentary lifestyle due to fear of exercise-induced episodes of atrial fibrillation. The burden of arrhythmia can be reduced by physical exercise...

Arrhythmias and hemodialysis: role of potassium and new diagnostic tools.

Science.gov (United States)

Buemi, Michele; Coppolino, Giuseppe; Bolignano, Davide; Sturiale, Alessio; Campo, Susanna; Buemi, Antoine; Crascì, Eleonora; Romeo, Adolfo

2009-01-01

Cardiovascular diseases represent the main causes of death in patients affected by renal failure, and arrhythmias are frequently observed in patients undergoing hemodialysis. Dialytic treatment per se can be considered as an arrhythmogenic stimulus; moreover, uraemic patients are characterized by a "pro-arrhythmic substrate" because of the high prevalence of ischaemic heart disease, left ventricular hypertrophy and autonomic neuropathy. One of the most important pathogenetic element involved in the onset of intra-dialytic arrhythmias is the alteration in electrolytes concentration, particularly calcium and potassium. It may be very useful to monitor the patient's cardiac activity during the whole hemodilaytic session. Nevertheless, the application of an extended intradialytic electrocardiographic monitoring is not simple because of several technical and structural impairments. We tried to overcome these difficulties using Whealthy, a wearable system consisting in a t-shirt composed of conductors and piezoresistive materials, integrated to form fibers and threads connected to tissutal sensors, electrodes, and connectors. ECG and pneumographic impedance signals are acquired by the electrodes in the tissue, and the data are registered by a small computer and transmitted via GPRS or Bluetooth.

An extended family suddenly confronted with a life-threatening hereditary arrhythmia

NARCIS (Netherlands)

Hendriks, K. S. W. H.; van Langen, I. M.; van Tintelen, J. P.; Grosfeld, F. J. M.; Wilde, A. A. M.; ten Kroode, H. F. J.

2005-01-01

This exploratory study serves to illustrate the psychological impact on an extended family in the process of genetic counselling and testing for a potentially life-threatening arrhythmia, the long-QT syndrome (LQTS). All members of the third generation and their partners (n=11) were interviewed, the

N-3 fatty acids from fish and markers of cardiac arrhythmia

NARCIS (Netherlands)

Geelen, A.

2004-01-01

N‑3 fatty acids from fish may protect against heart disease mortality by preventing fatal arrhythmias. The objective of this thesis was to investigate whether this possible antiarrhythmic effect of n-3 fatty acids is supported by short-term effects on electrophysiological markers. We performed two

The Role of Biologically Active Ingredients from Natural Drug Treatments for Arrhythmias in Different Mechanisms.

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Li, Jie; Hu, Dan; Song, Xiaoli; Han, Tao; Gao, Yonghong; Xing, Yanwei

2017-01-01

Arrhythmia is a disease that is caused by abnormal electrical activity in the heart rate or rhythm. It is the major cause of cardiovascular morbidity and mortality. Although several antiarrhythmic drugs have been used in clinic for decades, their application is often limited by their adverse effects. As a result, natural drugs, which have fewer side effects, are now being used to treat arrhythmias. We searched for all articles on the role of biologically active ingredients from natural drug treatments for arrhythmias in different mechanisms in PubMed. This study reviews 19 natural drug therapies, with 18 active ingredient therapies, such as alkaloids, flavonoids, saponins, quinones, and terpenes, and two kinds of traditional Chinese medicine compound (Wenxin-Keli and Shensongyangxin), all of which have been studied and reported as having antiarrhythmic effects. The primary focus is the proposed antiarrhythmic mechanism of each natural drug agent. Conclusion . We stress persistent vigilance on the part of the provider in discussing the use of natural drug agents to provide a solid theoretical foundation for further research on antiarrhythmia drugs.

Ion Channel Trafficking: Control of Ion Channel Density as a Target for Arrhythmias?

Directory of Open Access Journals (Sweden)

Elise Balse

2017-10-01

Full Text Available The shape of the cardiac action potential (AP is determined by the contributions of numerous ion channels. Any dysfunction in the proper function or expression of these ion channels can result in a change in effective refractory period (ERP and lead to arrhythmia. The processes underlying the correct targeting of ion channels to the plasma membrane are complex, and have not been fully characterized in cardiac myocytes. Emerging evidence highlights ion channel trafficking as a potential causative factor in certain acquired and inherited arrhythmias, and therapies which target trafficking as opposed to pore block are starting to receive attention. In this review we present the current evidence for the mechanisms which underlie precise control of cardiac ion channel trafficking and targeting.

Recommendations regarding dietary intake and caffeine and alcohol consumption in patients with cardiac arrhythmias: what do you tell your patients to do or not to do?

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Glatter, Kathryn A; Myers, Richard; Chiamvimonvat, Nipavan

2012-10-01

The etiology of arrhythmias including atrial fibrillation is multifactorial. Most arrhythmias are associated with comorbid illnesses like hypertension, diabetes, thyroid disease, or advanced age. Although it is tempting to blame a stimulant like caffeine as a trigger for arrhythmias, the literature does not support this idea. There is no real benefit to having patients with arrhythmias limit their caffeine intake. Caffeine is a vasoactive substance that also may promote the release of norepinephrine and epinephrine. However, acute ingestion of caffeine (as coffee or tea) does not cause atrial fibrillation. Even patients suffering a myocardial infarction do not have an increased incidence of ventricular or other arrhythmias after ingesting several cups of coffee. Large epidemiologic studies have also failed to find a connection between the amount of coffee/caffeine used and the development of arrhythmias. As such, it does not make sense to suggest that patients with palpitations, paroxysmal atrial fibrillation, or supraventricular tachycardia, abstain from caffeine use. Energy drinks are a new phenomenon on the beverage market, with 30-50 % of young adults and teens using them regularly. Energy drinks are loaded with caffeine, sugar, and other chemicals that can stimulate the cardiac system. There is an increasing body of mainly anecdotal case reports describing arrhythmias or even sudden death triggered by exercise plus using energy drinks. Clearly, there must be more study in this area, but it is wise to either limit or avoid their use in patients with arrhythmias. Moderate to heavy alcohol use seems to be associated with the development of atrial fibrillation. The term "holiday heart" was coined back in 1978, to describe patients who had atrial fibrillation following binge alcohol use. Thus, it is reasonable to recommend to patients with arrhythmias that they limit their alcohol use, although unfortunately this treatment will likely not completely resolve their

Musical Tasks and Energetic Arousal.

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Lim, Hayoung A; Watson, Angela L

2018-03-08

Music is widely recognized as a motivating stimulus. Investigators have examined the use of music to improve a variety of motivation-related outcomes; however, these studies have focused primarily on passive music listening rather than active participation in musical activities. To examine the influence of participation in musical tasks and unique participant characteristics on energetic arousal. We used a one-way Welch's ANOVA to examine the influence of musical participation (i.e., a non-musical control and four different musical task conditions) upon energetic arousal. In addition, ancillary analyses of participant characteristics including personality, age, gender, sleep, musical training, caffeine, nicotine, and alcohol revealed their possible influence upon pretest and posttest energetic arousal scores. Musical participation yielded a significant relationship with energetic arousal, F(4, 55.62) = 44.38, p = .000, estimated ω2 = 0.60. Games-Howell post hoc pairwise comparisons revealed statistically significant differences between five conditions. Descriptive statistics revealed expected differences between introverts' and extraverts' energetic arousal scores at the pretest, F(1, 115) = 6.80, p = .010, partial η2= .06; however, mean differences failed to reach significance at the posttest following musical task participation. No other measured participant characteristics yielded meaningful results. Passive tasks (i.e., listening to a story or song) were related to decreased energetic arousal, while active musical tasks (i.e., singing, rhythm tapping, and keyboard playing) were related to increased energetic arousal. Musical task participation appeared to have a differential effect for individuals with certain personality traits (i.e., extroverts and introverts).

Family and population strategies for screening and counselling of inherited cardiac arrhythmias

NARCIS (Netherlands)

Van Langen, I.M.; Hofman, N.; Tan, H.L.; Wilde, A.A.M.

2004-01-01

Family screening in inherited cardiac arrhythmias has been performed in The Netherlands since 1996, when diagnostic DNA testing in long QT syndrome (LOTS) and hypertrophic cardiomyopathy (HCM) became technically possible. In multidisciplinary outpatient academic clinics, an adjusted protocol for

POPDC1S201F causes muscular dystrophy and arrhythmia by affecting protein trafficking

Science.gov (United States)

Schindler, Roland F.R.; Scotton, Chiara; Zhang, Jianguo; Passarelli, Chiara; Ortiz-Bonnin, Beatriz; Simrick, Subreena; Schwerte, Thorsten; Poon, Kar-Lai; Fang, Mingyan; Rinné, Susanne; Froese, Alexander; Nikolaev, Viacheslav O.; Grunert, Christiane; Müller, Thomas; Tasca, Giorgio; Sarathchandra, Padmini; Drago, Fabrizio; Dallapiccola, Bruno; Rapezzi, Claudio; Arbustini, Eloisa; Di Raimo, Francesca Romana; Neri, Marcella; Selvatici, Rita; Gualandi, Francesca; Fattori, Fabiana; Pietrangelo, Antonello; Li, Wenyan; Jiang, Hui; Xu, Xun; Bertini, Enrico; Decher, Niels; Wang, Jun; Brand, Thomas; Ferlini, Alessandra

2015-01-01

The Popeye domain–containing 1 (POPDC1) gene encodes a plasma membrane–localized cAMP-binding protein that is abundantly expressed in striated muscle. In animal models, POPDC1 is an essential regulator of structure and function of cardiac and skeletal muscle; however, POPDC1 mutations have not been associated with human cardiac and muscular diseases. Here, we have described a homozygous missense variant (c.602C>T, p.S201F) in POPDC1, identified by whole-exome sequencing, in a family of 4 with cardiac arrhythmia and limb-girdle muscular dystrophy (LGMD). This allele was absent in known databases and segregated with the pathological phenotype in this family. We did not find the allele in a further screen of 104 patients with a similar phenotype, suggesting this mutation to be family specific. Compared with WT protein, POPDC1S201F displayed a 50% reduction in cAMP affinity, and in skeletal muscle from patients, both POPDC1S201F and WT POPDC2 displayed impaired membrane trafficking. Forced expression of POPDC1S201F in a murine cardiac muscle cell line (HL-1) increased hyperpolarization and upstroke velocity of the action potential. In zebrafish, expression of the homologous mutation (popdc1S191F) caused heart and skeletal muscle phenotypes that resembled those observed in patients. Our study therefore identifies POPDC1 as a disease gene causing a very rare autosomal recessive cardiac arrhythmia and LGMD, expanding the genetic causes of this heterogeneous group of inherited rare diseases. PMID:26642364

AV-block and conduction slowing prevail over TdP arrhythmias in the methoxamine-sensitized pro-arrhythmic rabbit model.

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Varkevisser, Rosanne; Vos, Marc A; Beekman, Jet D; Tieland, Ralph G; Van Der Heyden, Marcel A

2015-01-01

The methoxamine-sensitized rabbit model is widely used to screen drugs for proarrhythmic properties, especially repolarization-dependent TdP arrhythmias. With the change of anesthesia and/or sensitizing agent, conduction disturbances have been reported as well. Therefore, we compared currently available in-house anesthetics in order to preserve arrhythmia sensitivity and preclude conduction disturbances. Rabbits were randomly assigned to 3 groups: (1) 35 mg/kg ketamine + 5 mg/kg xylazine; (2) 0.5 mL/kg hypnorm + 3 mg/kg midazolam; (3) 35 mg/kg ketamine + 20 mg/kg propofol. Anesthesia was maintained by 1.5% isoflurane. Concomitant infusion of methoxamine (17 μg/kg/min for 40 minutes) and dofetilide (10 μg/kg/min for 30 minutes) was used to induce arrhythmias. Sole methoxamine infusion exclusively decreased HR in groups 1 and 3. Dofetilide lengthened repolarization, followed in time by PQ/QRS prolongation, second-degree AV block, and subsequently TdP arrhythmias. TdP was seen in 80%, 0%, and 33% of the rabbits in groups 1, 2, and 3, respectively. Decreasing the dose of dofetilide to 5 μg/kg/min in ketamine/xylazine anesthetized rabbits resulted in a drop in TdP incidence (25%) while conduction disturbances persisted. Flunarizine (n = 6) suppressed all TdP arrhythmias while conduction disturbances remained present. TdP incidence in the methoxamine-sensitized rabbit could be dramatically influenced by anesthesia, drug dose, and flunarizine, while conduction slowing remained present. Thus, conduction slowing seems to be the integral outcome in this model. © 2014 Wiley Periodicals, Inc.

Myocardial Energetics and Heart Failure: a Review of Recent Therapeutic Trials.

Science.gov (United States)

Bhatt, Kunal N; Butler, Javed

2018-06-01

Several novel therapeutics being tested in patients with heart failure are based on myocardial energetics. This review will provide a summary of the recent trials in this area, including therapeutic options targeting various aspects of cellular and mitochondrial metabolism. Agents that improve the energetic balance in myocardial cells have the potential to improve clinical heart failure status. The most promising therapies currently under investigation in this arena include (1) elamipretide, a cardiolipin stabilizer; (2) repletion of iron deficiency with intravenous ferrous carboxymaltose; (3) coenzyme Q10; and (4) the partial adenosine receptor antagonists capadenoson and neladenosone. Myocardial energetics-based therapeutics are groundbreaking in that they utilize novel mechanisms of action to improve heart failure symptoms, without causing the adverse neurohormonal side effects associated with current guideline-based therapies. The drugs appear likely to be added to the heart failure therapy armamentarium as adjuncts to current regimens in the near future.

Prevalence of Fibromyalgia Syndrome and Its Correlations with Arrhythmia in Patients with Palpitations

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Ayhan Aşkın

2018-04-01

Full Text Available Objective: It is aimed to determine the prevalence of fibromyalgia syndrome (FMS and its correlations with arrhythmia in patients with palpitations. Material and Methods: Sixty-two patients who underwent electrophysiological study (EPS due to palpitation complaints in Cardiology department and 40 healthy controls were included in the study. The precise diagnosis of arrhythmia was established using EPS. All participants were screened for FMS using American College of Rheumatology 2010 Fibromyalgia diagnostic criteria. Clinical assessments included measurement of severity of pain, fatigue and morning fatigue with visual analog scale (VAS, functional status with Fibromyalgia Impact Questionnaire (FIQ, and anxiety/depression with Hospital Anxiety and Depression Scale (HAD. Results: FMS was diagnosed in 22 of the 62 patients (36%, and 4 of the 40 healthy controls (10% (p 0.05. EPS+ patients with FMS had higher fatigue levels, HAD and FIQ scores than EPS− patients, although statistically insignificant. HV durations were statistically longer in the EPS− subgroup (p < 0.05 but other EPS data were similar. Conclusion: FMS frequency and HAD anxiety scores were found to be higher in patients with palpitation complaints. However, we found no association between arrhythmia, EPS parameters and FMS. In our clinical practice we should keep in mind to carry out assessments in terms of FMS in patients with palpitation.

SIMULATION OF ENERGETIC NEUTRAL ATOMS FROM SOLAR ENERGETIC PARTICLES

Energy Technology Data Exchange (ETDEWEB)

Wang, Linghua [Institute of Space Physics and Applied Technology, Peking University, Beijing 100871 (China); Li, Gang [Department of Space Science and CSPAR, University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Shih, Albert Y. [Solar Physics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20770 (United States); Lin, Robert P. [Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 (United States); Wimmer-Schweingruber, Robert F., E-mail: wanglhwang@gmail.com [Institut fuer Experimentelle und Angewandte Physik, University of Kiel, Leibnizstrasse 11, D-24118 Kiel (Germany)

2014-10-01

Energetic neutral atoms (ENAs) provide the only way to observe the acceleration site of coronal-mass-ejection-driven (CME-driven) shock-accelerated solar energetic particles (SEPs). In gradual SEP events, energetic protons can charge exchange with the ambient solar wind or interstellar neutrals to become ENAs. Assuming a CME-driven shock with a constant speed of 1800 km s{sup –1} and compression ratio of 3.5, propagating from 1.5 to 40 R{sub S} , we calculate the accelerated SEPs at 5-5000 keV and the resulting ENAs via various charge-exchange interactions. Taking into account the ENA losses in the interplanetary medium, we obtain the flux-time profiles of these solar ENAs reaching 1 AU. We find that the arriving ENAs at energies above ∼100 keV show a sharply peaked flux-time profile, mainly originating from the shock source below 5 R{sub S} , whereas the ENAs below ∼20 keV have a flat-top time profile, mostly originating from the source beyond 10 R{sub S} . Assuming the accelerated protons are effectively trapped downstream of the shock, we can reproduce the STEREO ENA fluence observations at ∼2-5 MeV/nucleon. We also estimate the flux of ENAs coming from the charge exchange of energetic storm protons, accelerated by the fast CME-driven shock near 1 AU, with interstellar hydrogen and helium. Our results suggest that appropriate instrumentation would be able to detect ENAs from SEPs and to even make ENA images of SEPs at energies above ∼10-20 keV.

Cardiac Arrhythmia: In vivo screening in the zebrafish to overcome complexity in drug discovery.

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Macrae, Calum A

2010-07-01

IMPORTANCE OF THE FIELD: Cardiac arrhythmias remain a major challenge for modern drug discovery. Clinical events are paroxysmal, often rare and may be asymptomatic until a highly morbid complication. Target selection is often based on limited information and though highly specific agents are identified in screening, the final efficacy is often compromised by unanticipated systemic responses, a narrow therapeutic index and substantial toxicities. AREAS COVERED IN THIS REVIEW: Our understanding of complexity of arrhythmogenesis has grown dramatically over the last two decades, and the range of potential disease mechanisms now includes pathways previously thought only tangentially involved in arrhythmia. This review surveys the literature on arrhythmia mechanisms from 1965 to the present day, outlines the complex biology underlying potentially each and every rhythm disturbance, and highlights the problems for rational target identification. The rationale for in vivo screening is described and the utility of the zebrafish for this approach and for complementary work in functional genomics is discussed. Current limitations of the model in this setting and the need for careful validation in new disease areas are also described. WHAT THE READER WILL GAIN: An overview of the complex mechanisms underlying most clinical arrhythmias, and insight into the limits of ion channel conductances as drug targets. An introduction to the zebrafish as a model organism, in particular for cardiovascular biology. Potential approaches to overcoming the hurdles to drug discovery in the face of complex biology including in vivo screening of zebrafish genetic disease models. TAKE HOME MESSAGE: In vivo screening in faithful disease models allows the effects of drugs on integrative physiology and disease biology to be captured during the screening process, in a manner agnostic to potential drug target or targets. This systematic strategy bypasses current gaps in our understanding of disease

Reduction of false arrhythmia alarms using signal selection and machine learning

NARCIS (Netherlands)

Eerikäinen, L.M.; Vanschoren, J.; Rooijakkers, M.J.; Vullings, R.; Aarts, R.M.

2016-01-01

In this paper, we propose an algorithm that classifies whether a generated cardiac arrhythmia alarm is true or false. The large number of false alarms in intensive care is a severe issue. The noise peaks caused by alarms can be high and in a noisy environment nurses can experience stress and

Transcatheter radiofrequency ablation under the guidance of three-dimensional mapping for the treatment of complex cardiac arrhythmias

International Nuclear Information System (INIS)

Hong Lang; Wang Hong; Lai Hengli; Ying Qiulin; Chen Zhangqiang; Lu Linxiang; Qiu Yun; Xiao Chengwei

2010-01-01

Objective: To investigate the effectiveness and safety of transcatheter radiofrequency ablation guided by a three-dimensional mapping system (Ensite or Carto) for the treatment of complex cardiac arrhythmias. Methods: A cohort of 123 consecutive hospitalized inpatients during the period from February 2006 to December 2008 were selected for this study. These patients suffered from various arrhythmias, including paroxysmal atrial fibrillation (n = 58), persistent or permanent atrial fibrillation (n = 10), atrial flutter (n = 13), atrial tachycardia (n = 12) and ventricular tachycardia or frequent ventricular premature beats (n = 30). Transcatheter radiofrequency ablation for arrhythmias was performed under the guidance of an EnSite3000 / NavX or Array mapping system in 80 cases, and under the guidance of a CARTO mapping system in the remaining 43 cases. Results: Successful ablation of arrhythmias was obtained by single operation in 106 cases (86.18%), including 59 cases with atrial fibrillation, 11 cases with atrial flutter, 10 cases with atrial tachycardia, and 26 cases with ventricular tachycardia or premature ventricular beat.Ablation procedure was carried out and was successful in 10 cases with a successful rate of 94.31%, including 5 cases with atrial fibrillation, 1 case with recurred atrial flutter, 1 case with recurrent atrial tachycardia, and 3 cases with ventricular tachycardia or premature ventricular beat.After operation, complications occurred in 6 cases, including cardiac tamponade in 4 cases, distal embolism of the left anterior descending coronary artery in 1 case, and pulmonary embolism in 1 case. Conclusion: Three-dimensional mapping system can clearly and stereoscopically display the cardiac structures. Therefore, this technique is of great value in guiding the transcatheter radiofrequency ablation for complex arrhythmias, in improving the success rate of ablation and in increasing the safety of the procedure. (authors)

Molecular approaches to solar energy conversion: the energetic cost of charge separation from molecular-excited states.

Science.gov (United States)

Durrant, James R

2013-08-13

This review starts with a brief overview of the technological potential of molecular-based solar cell technologies. It then goes on to focus on the core scientific challenge associated with using molecular light-absorbing materials for solar energy conversion, namely the separation of short-lived, molecular-excited states into sufficiently long-lived, energetic, separated charges capable of generating an external photocurrent. Comparisons are made between different molecular-based solar cell technologies, with particular focus on the function of dye-sensitized photoelectrochemical solar cells as well as parallels with the function of photosynthetic reaction centres. The core theme of this review is that generating charge carriers with sufficient lifetime and a high quantum yield from molecular-excited states comes at a significant energetic cost-such that the energy stored in these charge-separated states is typically substantially less than the energy of the initially generated excited state. The role of this energetic loss in limiting the efficiency of solar energy conversion by such devices is emphasized, and strategies to minimize this energy loss are compared and contrasted.

A multicenter, long-term study on arrhythmias in children with Ebstein anomaly.

NARCIS (Netherlands)

Delhaas, T.; Sarvaas, G.J.; Rijlaarsdam, M.E.; Strengers, J.L.; Eveleigh, R.M.; Poulino, S.E.; Korte, C.L. de; Kapusta, L.

2010-01-01

To assess the prevalence, history, and treatment of arrhythmias, in particular preexcitation and Wolff-Parkinson-White (WPW) syndrome, in patients with Ebstein anomaly (EA) during childhood and adolescence, we performed a multicenter retrospective study of all consecutive live-born patients with EA,

A Multicenter, Long-Term Study on Arrhythmias in Children with Ebstein Anomaly

NARCIS (Netherlands)

Delhaas, Tammo; Sarvaas, Gideon J. du Marchie; Rijlaarsdam, Marry E.; Strengers, Jan L.; Eveleigh, Rhona M.; Poulino, Sumayah E.; de Korte, Chris L.; Kapusta, Livia

To assess the prevalence, history, and treatment of arrhythmias, in particular preexcitation and Wolff-Parkinson-White (WPW) syndrome, in patients with Ebstein anomaly (EA) during childhood and adolescence, we performed a multicenter retrospective study of all consecutive live-born patients with EA,

[Treatment of arrhythmia in coronary patients and hypertensives with beta blockers and Depasan retard].

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Kandziora, J

1981-05-14

In the ambulatory of an internal specialist a number of patients suffering from angina pectoris or hypertonia together with arrhythmic troubles received an initial treatment with beta-blockers over a period of 21 days. In cases in which arrhythmia persisted after this initial period the treatment was continued for another 21 days with the addition of Depasan retard in function of a second medicament. This combined treatment in form of an open study was extended to a total number of 50 patients presenting ventricular extrasystolia in 45 cases and in 5 cases absolute arrhythmia in addition to the main disease. Treatment with Depasan retard showed good or satisfactory results in 39 out of 45 patients suffering from ventricular extrasystoles, whilst no effect could be obtained in the 5 cases with absolute arrhythmia. No signs of incompatibility or unwanted interactions were observed in the course of this open study. Based on these results it can be concluded that Depasan retard should be recommended in those cases where on account of persistent arrhythmical troubles and especially extrasystoles, during a treatment with beta-blockers in patients suffering from angina pectoris or hypertonia, and additional treatment with anti-arrhythmical medicaments appears to be indicated.

Automatic recognition of cardiac arrhythmias based on the geometric patterns of Poincaré plots

International Nuclear Information System (INIS)

Zhang, Lijuan; Guo, Tianci; Xi, Bin; Fan, Yang; Wang, Kun; Bi, Jiacheng; Wang, Ying

2015-01-01

The Poincaré plot emerges as an effective tool for assessing cardiovascular autonomic regulation. It displays nonlinear characteristics of heart rate variability (HRV) from electrocardiographic (ECG) recordings and gives a global view of the long range of ECG signals. In the telemedicine or computer-aided diagnosis system, it would offer significant auxiliary information for diagnosis if the patterns of the Poincaré plots can be automatically classified. Therefore, we developed an automatic classification system to distinguish five geometric patterns of the Poincaré plots from four types of cardiac arrhythmias. The statistics features are designed on measurements and an ensemble classifier of three types of neural networks is proposed. Aiming at the difficulty to set a proper threshold for classifying the multiple categories, the threshold selection strategy is analyzed. 24 h ECG monitoring recordings from 674 patients, which have four types of cardiac arrhythmias, are adopted for recognition. For comparison, Support Vector Machine (SVM) classifiers with linear and Gaussian kernels are also applied. The experiment results demonstrate the effectiveness of the extracted features and the better performance of the designed classifier. Our study can be applied to diagnose the corresponding sinus rhythm and arrhythmia substrates disease automatically in the telemedicine and computer-aided diagnosis system. (paper)

Photoactive energetic materials

Science.gov (United States)

Chavez, David E.; Hanson, Susan Kloek; Scharff, Robert Jason; Veauthier, Jacqueline Marie; Myers, Thomas Winfield

2018-02-27

Energetic materials that are photoactive or believed to be photoactive may include a conventional explosive (e.g. PETN, nitroglycerine) derivatized with an energetic UV-absorbing and/or VIS-absorbing chromophore such as 1,2,4,5-tetrazine or 1,3,5-triazine. Absorption of laser light having a suitably chosen wavelength may result in photodissociation, decomposition, and explosive release of energy. These materials may be used as ligands to form complexes. Coordination compounds include such complexes with counterions. Some having the formula M(L).sub.n.sup.2+ were synthesized, wherein M is a transition metal and L is a ligand and n is 2 or 3. These may be photoactive upon exposure to a laser light beam having an appropriate wavelength of UV light, near-IR and/or visible light. Photoactive materials also include coordination compounds bearing non-energetic ligands; in this case, the counterion may be an oxidant such as perchlorate.

O-GlcNAcylation of cardiac Nav1.5 contributes to the development of arrhythmias in diabetic hearts.

Science.gov (United States)

Yu, Peng; Hu, Lili; Xie, Jinyan; Chen, Sisi; Huang, Lin; Xu, Zixuan; Liu, Xiao; Zhou, Qiongqiong; Yuan, Ping; Yan, Xia; Jin, Jiejin; Shen, Yang; Zhu, Wengen; Fu, Linghua; Chen, Qi; Yu, Jianhua; Hu, Jianxin; Cao, Qing; Wan, Rong; Hong, Kui

2018-06-01

Cardiovascular complications are major causes of mortality and morbidity in diabetic patients. The mechanisms underlying the progression of diabetic heart (DH) to ventricular arrhythmias are unclear. O-linked GlcNAcylation (O-GlcNAc) is a reversible post-translational modification for the regulation of diverse cellular processes. The purpose of this study was to assess whether the cardiac voltage-gated sodium channel (Nav1.5) is subjected to O-linked GlcNAcylation (O-GlcNAc), which plays an essential role in DH-induced arrhythmias. In this study, Sprague-Dawley rats (male, 200-230 g) were treated with a single high-dose of streptozotocin (STZ, 80 mg/kg) to generate a rat model of diabetes. STZ-induced 3-month diabetic rats displayed increased susceptibility to ventricular arrhythmias. The elevated O-GlcNAc modification was correlated with decreases in both total and cytoplasmic Nav1.5 expression in vivo and in vitro. In addition, both co-immunoprecipitation and immunostaining assays demonstrated that hyperglycemia could increase the O-GlcNAc-modified Nav1.5 levels and decrease the interaction between Nav1.5 and Nav1.5-binding proteins Nedd4-2/SAP-97. Furthermore, patch-clamp measurements in HEK-293 T cells showed that Nav1.5 current densities decreased by 30% after high-glucose treatment, and the sodium currents increased via O-GlcNAc inhibition. Our data suggested that hyperglycemia increased the O-GlcNAc modification of Nav1.5 expression and decreased the interaction between Nav1.5 and Nedd4-2/SAP-97, which led to the abnormal expression and distribution of Nav1.5, loss of function of the sodium channel, and prolongation of the PR/QT interval. Excessive O-GlcNAc modification of Nav1.5 is a novel signaling event, which may be an underlying contributing factor for the development of the arrhythmogenesis in DH. Copyright © 2017. Published by Elsevier B.V.

Risk of malignant arrhythmias in initially symptomatic patients with Wolff-Parkinson-White syndrome: results of a prospective long-term electrophysiological follow-up study.

Science.gov (United States)

Pappone, Carlo; Vicedomini, Gabriele; Manguso, Francesco; Baldi, Mario; Pappone, Alessia; Petretta, Andrea; Vitale, Raffaele; Saviano, Massimo; Ciaccio, Cristiano; Giannelli, Luigi; Calovic, Zarko; Tavazzi, Luigi; Santinelli, Vincenzo

2012-02-07

The available amount of detailed long-term data in patients with Wolff-Parkinson-White syndrome is limited, and no prospective electrophysiological studies looking at predictors of malignant arrhythmia are available. Among 8575 symptomatic Wolff-Parkinson-White patients with atrioventricular reentrant tachycardia referred for electrophysiological test, 369 (mean age, 23±12.5 years) declined catheter ablation and were followed up. The primary end point of the study was to evaluate over a 5-year follow-up the predictors and characteristics of patients who develop malignant arrhythmias. After a mean follow-up of 42.1±10 months, malignant arrhythmias developed in 29 patients (mean age, 13.9±5.6 years; 26 male), resulting in presyncope/syncope (25 patients), hemodynamic collapse (3 patients), or cardiac arrest caused by ventricular fibrillation (1 patient). Of the remaining 340 patients, 168 (mean age, 34.2±9.0 years) remained asymptomatic up to 5 years, and 172 (mean age, 13.6±5.1 years) had benign recurrence, including sustained atrioventricular reentrant tachycardia (132 patients) or atrial fibrillation (40 patients). Compared with the group with no malignant arrhythmias, the group with malignant arrhythmias showed shorter accessory-pathway effective refractory period (PWolff-Parkinson-White syndrome generally have a good outcome, and predictors of malignant arrhythmias are similar to those reported for asymptomatic patients with ventricular pre-excitation.

Predictors of the left ventricular dysfunction induced by ventricular arrhythmia

Directory of Open Access Journals (Sweden)

А. І. Vytryhovskiy

2016-08-01

Full Text Available The most powerful predictor of life-threatening arrhythmia risk is a combination of low heart rate variability with low ejection fraction (EF of the left ventricle. Aim. To identify predictors of left ventricle dysfunction which is induced by ventricular arrhythmia. Materials and methods. To diagnose structural changes of left ventricular functional capacity and reserves in patients with previous myocardial infarction and patients with high and very high cardiovascular risk by SCORE scale and for establishment the relationship between morphological heart changes and pathological phenomenon of heart turbulence echocardiography and study of heart rate turbulence variability were performed. 603 patients were selected for the research. All patients were divided into groups: group 1 – patients with coronary heart disease, but without associated risk factors, such as smoking, obesity, metabolic syndrome; group 2 – patients who smoke tobacco more than 2 years (very high cardiovascular risk by scale SCORE; group 3 – patients with metabolic syndrome without coronary heart disease or arterial hypertension (very high cardiovascular risk by scale SCORE. The control group consisted of 149 persons. Results. The feature of structural changes in patients with myocardial infarction and in patients with a high cardiovascular risk by SCORE with heart rate turbulence compared with cases without НRT is considerably thickening of the left interventricular septum in systole. Based on this, it can be argued that the emergence of ventricular arrhythmia and accordingly phenomenon of heart rate turbulence in patients with existing cardiovascular diseases and risk factors has both morphological and functional character. Significant difference of echocardioscopy parameters in patients with postinfarction cardiosclerosis and risk factors by the SCORE system was established by index of intraventricular septum thickness in systole, and in persons with high risk – in

Study on penetration-induced initiation of energetic fragment

Science.gov (United States)

Qiao, Xiangxin; Xu, Heyang

2017-09-01

In order to investigate penetration-induced initiation of energetic fragment penetrating target, PTFE/Al (mass ratio 73.5/26.5) pressed and sintered into a Ф8mm × 8mm cylinder. To form energetic fragment, the cylinder was put into a closed container made by 35CrMnSiA. The container is 12mm long, 2mm thick. Energetic fragments were launched by a 14.5mm ballistic gun with a series of velocities and the penetrate process was simulated by AUTODYN-3D. The results show that the stress peak of energetic material exceed the initiation threshold, and energetic material will deflagrate, when energetic fragments impact velocity more than 800 m/s. The research results can provide reference for designs of energetic warhead.

Mammalian energetics. Flexible energetics of cheetah hunting strategies provide resistance against kleptoparasitism.

Science.gov (United States)

Scantlebury, David M; Mills, Michael G L; Wilson, Rory P; Wilson, John W; Mills, Margaret E J; Durant, Sarah M; Bennett, Nigel C; Bradford, Peter; Marks, Nikki J; Speakman, John R

2014-10-03

Population viability is driven by individual survival, which in turn depends on individuals balancing energy budgets. As carnivores may function close to maximum sustained power outputs, decreased food availability or increased activity may render some populations energetically vulnerable. Prey theft may compromise energetic budgets of mesopredators, such as cheetahs and wild dogs, which are susceptible to competition from larger carnivores. We show that daily energy expenditure (DEE) of cheetahs was similar to size-based predictions and positively related to distance traveled. Theft at 25% only requires cheetahs to hunt for an extra 1.1 hour per day, increasing DEE by just 12%. Therefore, not all mesopredators are energetically constrained by direct competition. Other factors that increase DEE, such as those that increase travel, may be more important for population viability. Copyright © 2014, American Association for the Advancement of Science.

Sevoflurane causes less arrhythmias than desflurane after off-pump coronary artery bypass grafting: A pilot study

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Hemmerling Thomas

2010-01-01

Full Text Available Background: Volatile anesthetics provide myocardial protection during cardiac surgery. Sevoflurane and desflurane are both efficient agents that allow immediate extubation after off-pump coronary artery bypass grafting (OPCABG. This study compared the incidence of arrhythmias after OPCABG with the two agents. Materials and Methods: Forty patients undergoing OPCABG with immediate extubation and perioperative high thoracic analgesia were included in this controlled, double-blind study; anesthesia was either provided using 1 MAC of sevoflurane (SEVO-group or desflurane (DES-group. Monitoring of perioperative arrhythmias was provided by continuous monitoring of the EKG up to 72 hours after surgery, and routine EKG monitoring once every day, until time of discharge. Patient data, perioperative arrhythmias, and myocardial protection (troponin I, CK, CK-MB-ratio, and transesophageal echocardiography examinations were compared using t-test, Fisher′s exact test or two-way analysis of variance for repeated measurements; P < 0.05. Results: Patient data and surgery-related data were similar between the two groups; all the patients were successfully extubated immediately after surgery, with similar emergence times. Supraventricular tachycardia occurred only in the DES-group (5 of 20 patients, atrial fibrillation was significantly more frequent in the DES group versus SEVO-group, at five out of 20 versus one out of 20 patients, respectively. Myocardial protection was equally achieved in both groups. Discussion: Ultra-fast track anesthesia using sevoflurane seems more advantageous than desflurane for anesthesia, for OPCABG, as it is associated with significantly less atrial fibrillation or supraventricular arrhythmias after surgery.

Epicardial phrenic nerve displacement during catheter ablation of atrial and ventricular arrhythmias: procedural experience and outcomes.

Science.gov (United States)

Kumar, Saurabh; Barbhaiya, Chirag R; Baldinger, Samuel H; Koplan, Bruce A; Maytin, Melanie; Epstein, Laurence M; John, Roy M; Michaud, Gregory F; Tedrow, Usha B; Stevenson, William G

2015-08-01

Arrhythmia origin in close proximity to the phrenic nerve (PN) can hinder successful catheter ablation. We describe our approach with epicardial PN displacement in such instances. PN displacement via percutaneous pericardial access was attempted in 13 patients (age 49±16 years, 9 females) with either atrial tachycardia (6 patients) or atrial fibrillation triggered from a superior vena cava focus (1 patient) adjacent to the right PN or epicardial ventricular tachycardia origin adjacent to the left PN (6 patients). An epicardially placed steerable sheath/4 mm-catheter combination (5 patients) or a vascular or an esophageal balloon (8 patients) was ultimately successful. Balloon placement was often difficult requiring manipulation via a steerable sheath. In 2 ventricular tachycardia cases, absence of PN capture was achieved only once the balloon was directly over the ablation catheter. In 3 atrial tachycardia patients, PN displacement was not possible with a balloon; however, a steerable sheath/catheter combination was ultimately successful. PN displacement allowed acute abolishment of all targeted arrhythmias. No PN injury occurred acutely or in follow up. Two patients developed acute complications (pleuro-pericardial fistula 1 and pericardial bleeding 1). Survival free of target arrhythmia was achieved in all atrial tachycardia patients; however, a nontargeted ventricular tachycardia recurred in 1 patient at a median of 13 months' follow up. Arrhythmias originating in close proximity to the PN can be targeted successfully with PN displacement with an epicardially placed steerable sheath/catheter combination, or balloon, but this strategy can be difficult to implement. Better tools for phrenic nerve protection are desirable. © 2015 American Heart Association, Inc.

Anti-HERG activity and the risk of drug-induced arrhythmias and sudden death

DEFF Research Database (Denmark)

De Bruin, M L; Pettersson, M; Meyboom, R H B

2005-01-01

AIMS: Drug-induced QTc-prolongation, resulting from inhibition of HERG potassium channels may lead to serious ventricular arrhythmias and sudden death. We studied the quantitative anti-HERG activity of pro-arrhythmic drugs as a risk factor for this outcome in day-to-day practice. METHODS...... defined as reports of cardiac arrest, sudden death, torsade de pointes, ventricular fibrillation, and ventricular tachycardia (n = 5591), and compared with non-cases regarding the anti-HERG activity, defined as the effective therapeutic plasma concentration (ETCPunbound) divided by the HERG IC50 value......, of suspected drugs. We identified a significant association of 1.93 (95% CI: 1.89-1.98) between the anti-HERG activity of drugs, measured as log10 (ETCPunbound/IC50), and reporting of serious ventricular arrhythmias and sudden death to the WHO-UMC database. CONCLUSION: Anti-HERG activity is associated...

AANA Journal Course: update for nurse anesthetists. Arrhythmia management devices and electromagnetic interference.

Science.gov (United States)

Mattingly, Emily

2005-04-01

The technological complexity of implantable arrhythmia management devices, specifically pacemakers and defibrillators, has increased dramatically since their introduction only a few decades ago. Patients with such devices are encountered much more frequently in hospitals and surgery centers, yet anesthesia provider knowledge of safe and proper management is often incomplete. Anesthesia textbooks and references may provide only short paragraphs on arrhythmia management devices that do not address important perioperative management strategies for this ever-growing patient population. It is no longer satisfactory to simply place a magnet over an implanted device during surgery and assume that this action protects the patient from harm due to electromagnetic interference from inappropriate device function. This AANA Journal course serves as a concise review of basic device function, the sources and effects of electromagnetic interference in the operative setting, and patient management recommendations from current literature.

Scintigraphic assessment of cardiac sympathetic innervation with I-123-metaiodobenzylguanidine in cardiomyopathy. Special reference to cardiac arrhythmia

Energy Technology Data Exchange (ETDEWEB)

Asano, Takahisa; Otsuka, Nobuaki; Sone, Teruki; Mimura, Hiroaki; Yanagimoto, Shinichi; Tomomitsu, Tatsushi; Fukunaga, Masao [Kawasaki Medical School, Kurashiki, Okayama (Japan); Morita, Koichi

1999-07-01

Cardiac sympathetic imagings with I-123-metaiodobenzylguanidine (MIBG) were carried out in 5 cases with dilated cardiomyopathy (DCM), 26 cases with hypertrophic cardiomyopathy (HCM), and 4 cases without cardiac disease as a control to assess cardiac sympathetic innervation qualitatively and quantitatively, and to clarify the relation of MIBG accumulation to arrhythmia. MIBG scintigraphy was performed at 15 min. (early image) and 4 hr. (delayed image) after intravenous injection of MIBG 111 MBq. The MIBG uptake ratio of mediastinum (H/M) and the cardiac washout rate (WR) from early to delayed images were calculated. On both early and delayed SPECTs, MIBG uptake was assessed by defect scores (DSs). Regarding the cases with HCM, the MIBG uptake ratio, WR, and DS were also compared in cases with and without arrhythmia. In DCM, the MIBG uptake on delayed SPECT was markedly low, the H/M ratio was significantly lower, and the DS was significantly higher than in the control (all p<0.05). As for the WR, there was no significant difference between HCM, DCM and the control. In HCM, significantly reduced MIBG uptake was observed in cases with ventricular techycardia (VT) and in cases with atrial fibrillation (Af), as compared with cases without arrhythmia (all p<0.05). There results suggest that MIBG scintigraphy might be a useful tool in the assessment of cardiac sympathetic abnormalities in cardiomyopathy, especially in cases with arrhythmia. (author)

Late gadolinium enhancement by magnetic resonance explains adverse cardiac events in individuals with ventricular arrhythmia

International Nuclear Information System (INIS)

Courtis, J.; Vasallo, J.; Arabia, L.; Dimitroff, M.; Gonzalez, A.; Tibaldi, M.

2012-01-01

Objective: To determine whether the presence of late gadolinium enhancement (LGE) by cardiovascular magnetic resonance (CMR) predict adverse cardiac events in patients with ventricular arrhythmia. Methods: We selected 74 consecutive patients with symptomatic ventricular arrhythmia (premature ventricular contractions and ventricular tachycardia) and left ventricular ejection fraction (LVEF) >55% sent to CMR for evaluation of structural heart disease previously undetected by other complementary methods. LGE, systolic function and volumes of both ventricles were analyzed. At follow-up was assessed a combined end point: hospitalization for ventricular arrhythmia, appropriate implantable cardioverter-defibrillator therapy and cardiac death. Results: During a median follow up of 575 days (interquartile range 24-1120 days) and by analyzing the population according to the presence (n=9, 12%) or not (n=65, 88%) LGE was observed that the group with positive Gd had lower LVEF (58% vs. 66% respectively, p=0.01) and larger volumes (EDV: 185 ml vs. 123 ml respectively, p=0.01 and ESV: 81 ml vs. 42 ml respectively, p=0.01) than the other group. Two (22%) patients in the LGE + group vs. one (4%) of those without LGE showed the combined endpoint (p=0.01) and when performing a logistic regression analysis it was found that the LGE is a predictor of adverse cardiac events analyzed (p=0.029). Conclusions: In this consecutive series of patients with ventricular arrhythmia we demonstrate a strong association between myocardial LGE and adverse cardiac events; this supports the hypothesis that myocardial fibrosis is an important arrhythmogenic substrate. In addition, almost all individuals without LGE were free of events during follow-up suggesting that it is possible to identify through the CMR low-risk individuals who can be treated conservatively. (authors) [es

Dental caries, periodontal disease, and cardiac arrhythmias in community-dwelling older persons aged 80 and older: is there a link?

DEFF Research Database (Denmark)

Holm-Pedersen, Poul; Avlund, Kirsten; Morse, Douglas E

2005-01-01

lesions had 2.8 times higher odds (95% confidence interval=1.1-7.0) of arrhythmia than persons without active coronal caries, but there was no greater risk for persons with three or more coronal caries lesions. There was no association between periodontal disease and arrhythmia. CONCLUSION: The findings......OBJECTIVES: To examine whether caries or periodontitis is associated with cardiac arrhythmias in community-dwelling people aged 80 and older. SETTING: Urban, community-based population in Stockholm, Sweden. DESIGN: Cross-sectional. PARTICIPANTS: Eligible persons were identified through...... by a physician or the Stockholm Inpatient Register. Active root caries, active coronal caries, and periodontitis were assessed using previously defined National Institute of Dental and Craniofacial Research diagnostic criteria. RESULTS: The primary finding of the multivariate logistic regression analysis...

Rural energetic development: cuban experience

International Nuclear Information System (INIS)

Aguilera Barciela, M.

1994-01-01

The development of electro energetic national system in Cuba has been directed to the following objectives: to brake the rural population's exodus toward the cities, electrification of dairy farm, interconnection to the system electro energetic of all the sugar central production, these improves the rural population's conditions life

Arrhythmia Mechanism and Scaling Effect on the Spectral Properties of Electroanatomical Maps With Manifold Harmonics.

Science.gov (United States)

Sanroman-Junquera, Margarita; Mora-Jimenez, Inmaculada; Garcia-Alberola, Arcadio; Caamano, Antonio J; Trenor, Beatriz; Rojo-Alvarez, Jose L

2018-04-01

Spatial and temporal processing of intracardiac electrograms provides relevant information to support the arrhythmia ablation during electrophysiological studies. Current cardiac navigation systems (CNS) and electrocardiographic imaging (ECGI) build detailed 3-D electroanatomical maps (EAM), which represent the spatial anatomical distribution of bioelectrical features, such as activation time or voltage. We present a principled methodology for spectral analysis of both EAM geometry and bioelectrical feature in CNS or ECGI, including their spectral representation, cutoff frequency, or spatial sampling rate (SSR). Existing manifold harmonic techniques for spectral mesh analysis are adapted to account for a fourth dimension, corresponding to the EAM bioelectrical feature. Appropriate scaling is required to address different magnitudes and units. With our approach, simulated and real EAM showed strong SSR dependence on both the arrhythmia mechanism and the cardiac anatomical shape. For instance, high frequencies increased significantly the SSR because of the "early-meets-late" in flutter EAM, compared with the sinus rhythm. Besides, higher frequency components were obtained for the left atrium (more complex anatomy) than for the right atrium in sinus rhythm. The proposed manifold harmonics methodology opens the field toward new signal processing tools for principled EAM spatiofeature analysis in CNS and ECGI, and to an improved knowledge on arrhythmia mechanisms.

hERG trafficking inhibition in drug-induced lethal cardiac arrhythmia.

Science.gov (United States)

Nogawa, Hisashi; Kawai, Tomoyuki

2014-10-15

Acquired long QT syndrome induced by non-cardiovascular drugs can cause lethal cardiac arrhythmia called torsades de points and is a significant problem in drug development. The prolongation of QT interval and cardiac action potential duration are mainly due to reduced physiological function of the rapidly activating voltage-dependent potassium channels encoded by human ether-a-go-go-related gene (hERG). Structurally diverse groups of drugs are known to directly inhibit hERG channel conductance. Therefore, the ability of acute hERG inhibition is routinely assessed at the preclinical stages in pharmaceutical testing. Recent findings indicated that chronic treatment with various drugs not only inhibits hERG channels but also decreases hERG channel expression in the plasma membrane of cardiomyocytes, which has become another concern in safety pharmacology. The mechanisms involve the disruption of hERG trafficking to the surface membrane or the acceleration of hERG protein degradation. From this perspective, we present a brief overview of mechanisms of drug-induced trafficking inhibition and pathological regulation. Understanding of drug-induced hERG trafficking inhibition may provide new strategies for predicting drug-induced QT prolongation and lethal cardiac arrhythmia in pharmaceutical drug development. Copyright © 2014 Elsevier B.V. All rights reserved.

Observational cohort study of ventricular arrhythmia in adults with Marfan syndrome caused by FBN1 mutations.

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Ali Aydin

Full Text Available Marfan syndrome is associated with ventricular arrhythmia but risk factors including FBN1 mutation characteristics require elucidation.We performed an observational cohort study of 80 consecutive adults (30 men, 50 women aged 42±15 years with Marfan syndrome caused by FBN1 mutations. We assessed ventricular arrhythmia on baseline ambulatory electrocardiography as >10 premature ventricular complexes per hour (>10 PVC/h, as ventricular couplets (Couplet, or as non-sustained ventricular tachycardia (nsVT, and during 31±18 months of follow-up as ventricular tachycardia (VT events (VTE such as sudden cardiac death (SCD, and sustained ventricular tachycardia (sVT. We identified >10 PVC/h in 28 (35%, Couplet/nsVT in 32 (40%, and VTE in 6 patients (8%, including 3 with SCD (4%. PVC>10/h, Couplet/nsVT, and VTE exhibited increased N-terminal pro-brain natriuretic peptide serum levels(P10/h and Couplet/nsVT also related to increased indexed end-systolic LV diameters (P = .024 and P = .020, to moderate mitral valve regurgitation (P = .018 and P = .003, and to prolonged QTc intervals (P = .001 and P = .006, respectively. Moreover, VTE related to mutations in exons 24-32 (P = .021. Kaplan-Meier analysis corroborated an association of VTE with increased NT-proBNP (P<.001 and with mutations in exons 24-32 (P<.001.Marfan syndrome with causative FBN1 mutations is associated with an increased risk for arrhythmia, and affected persons may require life-long monitoring. Ventricular arrhythmia on electrocardiography, signs of myocardial dysfunction and mutations in exons 24-32 may be risk factors of VTE.

Exercise-induced ventricular arrhythmias and vagal dysfunction in Chagas disease patients with no apparent cardiac involvement

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Henrique Silveira Costa

2015-04-01

Full Text Available INTRODUCTION : Exercise-induced ventricular arrhythmia (EIVA and autonomic imbalance are considered as early markers of heart disease in Chagas disease (ChD patients. The objective of the present study was to verify the differences in the occurrence of EIVA and autonomic maneuver indexes between healthy individuals and ChD patients with no apparent cardiac involvement. METHODS : A total of 75 ChD patients with no apparent cardiac involvement, aged 44.7 (8.5 years, and 38 healthy individuals, aged 44.0 (9.2 years, were evaluated using echocardiography, symptom-limited treadmill exercise testing and autonomic function tests. RESULTS : The occurrence of EIVA was higher in the chagasic group (48% than in the control group (23.7% during both the effort and the recovery phases. Frequent ventricular contractions occurred only in the patient group. Additionally, the respiratory sinus arrhythmia index was significantly lower in the chagasic individuals compared with the control group. CONCLUSIONS : ChD patients with no apparent cardiac involvement had a higher frequency of EIVA as well as more vagal dysfunction by respiratory sinus arrhythmia. These results suggest that even when asymptomatic, ChD patients possess important arrhythmogenic substrates and subclinical disease.

The location of energetic compartments affects energetic communication in cardiomyocytes

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Rikke eBirkedal

2014-09-01

Full Text Available The heart relies on accurate regulation of mitochondrial energy supply to match energy demand. The main regulators are Ca2+ and feedback of ADP and Pi. Regulation via feedback has intrigued for decades. First, the heart exhibits a remarkable metabolic stability. Second, diffusion of ADP and other molecules is restricted specifically in heart and red muscle, where a fast feedback is needed the most. To explain the regulation by feedback, compartmentalization must be taken into account. Experiments and theoretical approaches suggest that cardiomyocyte energetic compartmentalization is elaborate with barriers obstructing diffusion in the cytosol and at the level of the mitochondrial outer membrane (MOM. A recent study suggests the barriers are organized in a lattice with dimensions in agreement with those of intracellular structures. Here, we discuss the possible location of these barriers. The more plausible scenario includes a barrier at the level of MOM. Much research has focused on how the permeability of MOM itself is regulated, and the importance of the creatine kinase system to facilitate energetic communication. We hypothesize that at least part of the diffusion restriction at the MOM level is not by MOM itself, but due to the close physical association between the sarcoplasmic reticulum (SR and mitochondria. This will explain why animals with a disabled creatine kinase system exhibit rather mild phenotype modifications. Mitochondria are hubs of energetics, but also ROS production and signaling. The close association between SR and mitochondria may form a diffusion barrier to ADP added outside a permeabilised cardiomyocyte. But in vivo, it is the structural basis for the mitochondrial-SR coupling that is crucial for the regulation of mitochondrial Ca2+-transients to regulate energetics, and for avoiding Ca2+-overload and irreversible opening of the mitochondrial permeability transition pore.

Physiology of stem cell-derived cardiomyocytes

NARCIS (Netherlands)

Boer, T.P. de

2007-01-01

All chapters in this thesis revolve around the general theme, stem cells and their electrophysiological characteristics and capacity to induce pro-arrhythmia. The first part of this thesis focusses on key aspects that are relevant to possible pro-arrhythmic effects of stem cell transplantation. An

Screening in crystalline liquids protects energetic carriers in hybrid perovskites

Science.gov (United States)

Zhu, Haiming; Miyata, Kiyoshi; Fu, Yongping; Wang, Jue; Joshi, Prakriti; Niesner, Daniel; Williams, Kristopher; Jin, Song; Zhu, Xiaoyang

Hybrid lead halide perovskites exhibit carrier properties that resemble those of pristine nonpolar semiconductors despite static and dynamic disorder, but how carriers are protected from efficient scattering with charged defects and optical phonons is unknown. Here, we reveal the carrier protection mechanism by comparing three single-crystal lead bromide perovskites: CH3NH3PbBr3, CH(NH2)2PbBr3, and CsPbBr3. We observed hot fluorescence emission from energetic carriers with 102 picosecond lifetimes in CH3NH3PbBr3 or CH(NH,SUB>2)2PbBr3, but not in CsPbBr3. The hot fluorescence is correlated with liquid-like molecular reorientational motions, suggesting that dynamic screening protects energetic carriers via solvation or large polaron formation on time scales competitive with that of ultrafast cooling. Similar protections likely exist for band-edge carriers. The long-lived energetic carriers may enable hot-carrier solar cells with efficiencies exceeding the Shockley-Queisser limit. This work was supported by U.S. Department of Energy Grant ER46980, National Science Foundation, Grant DMR 1420634 (MRSEC), and Department of Energy Award DE-FG02-09ER46664.

EIF2A-dependent translational arrest protects leukemia cells from the energetic stress induced by NAMPT inhibition

International Nuclear Information System (INIS)

Zucal, Chiara; D’Agostino, Vito G.; Casini, Antonio; Mantelli, Barbara; Thongon, Natthakan; Soncini, Debora; Caffa, Irene; Cea, Michele; Ballestrero, Alberto; Quattrone, Alessandro; Indraccolo, Stefano; Nencioni, Alessio; Provenzani, Alessandro

2015-01-01

Nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme in NAD + biosynthesis from nicotinamide, is one of the major factors regulating cancer cells metabolism and is considered a promising target for treating cancer. The prototypical NAMPT inhibitor FK866 effectively lowers NAD + levels in cancer cells, reducing the activity of NAD + -dependent enzymes, lowering intracellular ATP, and promoting cell death. We show that FK866 induces a translational arrest in leukemia cells through inhibition of MTOR/4EBP1 signaling and of the initiation factors EIF4E and EIF2A. Specifically, treatment with FK866 is shown to induce 5′AMP-activated protein kinase (AMPK) activation, which, together with EIF2A phosphorylation, is responsible for the inhibition of protein synthesis. Notably, such an effect was also observed in patients’ derived primary leukemia cells including T-cell Acute Lymphoblastic Leukemia. Jurkat cells in which AMPK or LKB1 expression was silenced or in which a non-phosphorylatable EIF2A mutant was ectopically expressed showed enhanced sensitivity to the NAMPT inhibitor, confirming a key role for the LKB1-AMPK-EIF2A axis in cell fate determination in response to energetic stress via NAD + depletion. We identified EIF2A phosphorylation as a novel early molecular event occurring in response to NAMPT inhibition and mediating protein synthesis arrest. In addition, our data suggest that tumors exhibiting an impaired LBK1- AMPK- EIF2A response may be especially susceptible to NAMPT inhibitors and thus become an elective indication for this type of agents. The online version of this article (doi:10.1186/s12885-015-1845-1) contains supplementary material, which is available to authorized users

Arrhythmia-provoking factors and symptoms at the onset of paroxysmal atrial fibrillation: A study based on interviews with 100 patients seeking hospital assistance

Directory of Open Access Journals (Sweden)

Madsen-Härdig Bjarne

2004-08-01

Full Text Available Abstract Background Surprisingly little information on symptoms of paroxysmal atrial fibrillation is available in scientific literature. Using questionnaires, we have analyzed the symptoms associated with arrhythmia attacks. Methods One hundred randomly-selected patients with idiopathic paroxysmal atrial fibrillation filled in a structured questionnaire. Results Psychic stress was the most common factor triggering arrhythmia (54%, followed by physical exertion (42%, tiredness (41% coffee (25% and infections (22%. Thirty-four patients cited alcohol, 26 in the form of red wine, 16 as white wine and 26 as spirits. Among these 34, red wine and spirits produced significantly more episodes of arrhythmia than white wine (p = 0.01 and 0.005 respectively. Symptoms during arrhythmia were palpitations while exerting (88%, reduced physical ability (87%, palpitations at rest (86%, shortage of breath during exertion (70% and anxiety (59%. Significant differences between sexes were noted regarding swollen legs (women 21%, men 6%, p = 0.027, nausea (women 36%, men 13%, p = 0.012 and anxiety (females 79%, males 51%, p = 0.014. Conclusion Psychic stress was the commonest triggering factor in hospitalized patients with paroxysmal atrial fibrillation. Red wine and spirits were more proarrhythmic than white wine. Symptoms in women in connection with attacks of arrhythmia vary somewhat from those in men.

The Principle of Energetic Consistency

Science.gov (United States)

Cohn, Stephen E.

2009-01-01

A basic result in estimation theory is that the minimum variance estimate of the dynamical state, given the observations, is the conditional mean estimate. This result holds independently of the specifics of any dynamical or observation nonlinearity or stochasticity, requiring only that the probability density function of the state, conditioned on the observations, has two moments. For nonlinear dynamics that conserve a total energy, this general result implies the principle of energetic consistency: if the dynamical variables are taken to be the natural energy variables, then the sum of the total energy of the conditional mean and the trace of the conditional covariance matrix (the total variance) is constant between observations. Ensemble Kalman filtering methods are designed to approximate the evolution of the conditional mean and covariance matrix. For them the principle of energetic consistency holds independently of ensemble size, even with covariance localization. However, full Kalman filter experiments with advection dynamics have shown that a small amount of numerical dissipation can cause a large, state-dependent loss of total variance, to the detriment of filter performance. The principle of energetic consistency offers a simple way to test whether this spurious loss of variance limits ensemble filter performance in full-blown applications. The classical second-moment closure (third-moment discard) equations also satisfy the principle of energetic consistency, independently of the rank of the conditional covariance matrix. Low-rank approximation of these equations offers an energetically consistent, computationally viable alternative to ensemble filtering. Current formulations of long-window, weak-constraint, four-dimensional variational methods are designed to approximate the conditional mode rather than the conditional mean. Thus they neglect the nonlinear bias term in the second-moment closure equation for the conditional mean. The principle of

Nonischemic Left Ventricular Scar as a Substrate of Life-Threatening Ventricular Arrhythmias and Sudden Cardiac Death in Competitive Athletes.

Science.gov (United States)

Zorzi, Alessandro; Perazzolo Marra, Martina; Rigato, Ilaria; De Lazzari, Manuel; Susana, Angela; Niero, Alice; Pilichou, Kalliopi; Migliore, Federico; Rizzo, Stefania; Giorgi, Benedetta; De Conti, Giorgio; Sarto, Patrizio; Serratosa, Luis; Patrizi, Giampiero; De Maria, Elia; Pelliccia, Antonio; Basso, Cristina; Schiavon, Maurizio; Bauce, Barbara; Iliceto, Sabino; Thiene, Gaetano; Corrado, Domenico

2016-07-01

The clinical profile and arrhythmic outcome of competitive athletes with isolated nonischemic left ventricular (LV) scar as evidenced by contrast-enhanced cardiac magnetic resonance remain to be elucidated. We compared 35 athletes (80% men, age: 14-48 years) with ventricular arrhythmias and isolated LV subepicardial/midmyocardial late gadolinium enhancement (LGE) on contrast-enhanced cardiac magnetic resonance (group A) with 38 athletes with ventricular arrhythmias and no LGE (group B) and 40 healthy control athletes (group C). A stria LGE pattern with subepicardial/midmyocardial distribution, mostly involving the lateral LV wall, was found in 27 (77%) of group A versus 0 controls (group C; P<0.001), whereas a spotty pattern of LGE localized at the junction of the right ventricle to the septum was respectively observed in 11 (31%) versus 10 (25%; P=0.52). All athletes with stria pattern showed ventricular arrhythmias with a predominant right bundle branch block morphology, 13 of 27 (48%) showed ECG repolarization abnormalities, and 5 of 27 (19%) showed echocardiographic hypokinesis of the lateral LV wall. The majority of athletes with no or spotty LGE pattern had ventricular arrhythmias with a predominant left bundle branch block morphology and no ECG or echocardiographic abnormalities. During a follow-up of 38±25 months, 6 of 27 (22%) athletes with stria pattern experienced malignant arrhythmic events such as appropriate implantable cardiac defibrillator shock (n=4), sustained ventricular tachycardia (n=1), or sudden death (n=1), compared with none of athletes with no or LGE spotty pattern and controls. Isolated nonischemic LV LGE with a stria pattern may be associated with life-threatening arrhythmias and sudden death in the athlete. Because of its subepicardial/midmyocardial location, LV scar is often not detected by echocardiography. © 2016 The Authors.

Arrhythmia causes lipid accumulation and reduced glucose uptake.

Science.gov (United States)

Lenski, Matthias; Schleider, Gregor; Kohlhaas, Michael; Adrian, Lucas; Adam, Oliver; Tian, Qinghai; Kaestner, Lars; Lipp, Peter; Lehrke, Michael; Maack, Christoph; Böhm, Michael; Laufs, Ulrich

2015-01-01

Atrial fibrillation (AF) is characterized by irregular contractions of atrial cardiomyocytes and increased energy demand. The aim of this study was to characterize the influence of arrhythmia on glucose and fatty acid (FA) metabolism in cardiomyocytes, mice and human left atrial myocardium. Compared to regular pacing, irregular (pseudo-random variation at the same number of contractions/min) pacing of neonatal rat cardiomyocytes induced shorter action potential durations and effective refractory periods and increased diastolic [Ca(2+)]c. This was associated with the activation of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) and AMP-activated protein kinase (AMPK). Membrane expression of fatty acid translocase (FAT/CD36) and (14)C-palmitic acid uptake were augmented while membrane expression of glucose transporter subtype 4 (GLUT-4) as well as (3)H-glucose uptake were reduced. Inhibition of AMPK and CaMKII prevented these arrhythmia-induced metabolic changes. Similar alterations of FA metabolism were observed in a transgenic mouse model (RacET) for spontaneous AF. Consistent with these findings samples of left atrial myocardium of patients with AF compared to matched samples of patients with sinus rhythm showed up-regulation of CaMKII and AMPK and increased membrane expression of FAT/CD36, resulting in lipid accumulation. These changes of FA metabolism were accompanied by decreased membrane expression of GLUT-4, increased glycogen content and increased expression of the pro-apoptotic protein bax. Irregular pacing of cardiomyocytes increases diastolic [Ca(2+)]c and activation of CaMKII and AMPK resulting in lipid accumulation, reduced glucose uptake and increased glycogen synthesis. These metabolic changes are accompanied by an activation of pro-apoptotic signalling pathways.

Second School of Nuclear Energetics

International Nuclear Information System (INIS)

2009-01-01

At 3-5 Nov 2009 Institute of Nuclear Energy POLATOM, Association of Polish Electrical Engineers (SEP) and Polish Nuclear Society have organized Second School of Nuclear Energetics. 165 participants have arrived from all Poland and represented both different central institutions (e.g. ministries) and local institutions (e.g. Office of Technical Inspection, The Voivodship Presidential Offices, several societies, consulting firms or energetic enterprises). Students from the Warsaw Technical University and Gdansk Technical University, as well as the PhD students from the Institute of Nuclear Chemistry and Technology (Warsaw) attended the School. 20 invited lectures presented by eminent Polish specialists concerned basic problems of nuclear energetics, nuclear fuel cycle and different problems of the NPP construction in Poland. [pl

Arritmias cardiacas generadas por heterogeneidad electrofisiológica: estudio mediante simulación Cardiac arrhythmias generated by electrophysiological heterogeneity: simulation study

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Oscar Henao

2007-08-01

Full Text Available Las arritmias ventriculares usualmente se presentan como consecuencia de isquemia miocárdica aguda, lo cual causa la mayoría de las muertes súbitas. La heterogeneidad cardiaca tanto funcional (diferente comportamiento eléctrico en los miocitos como bioquímica (diferentes concentraciones iónicas en isquemia, altera el comportamiento eléctrico del ventrículo y genera dispersión en la repolarización del potencial de acción, por lo que se convierte en sustrato funcional para la generación de arritmias fatales. En este trabajo se revisan las técnicas experimentales para el estudio y la detección de arritmias por reentrada, y se valida un modelo geométrico de isquemia, en presencia de heterogeneidad eléctrica en la región transmural de la pared ventricular. Para ello se utilizaron simulaciones bidimensionales de un modelo biofísicamente detallado y se obtuvieron reentradas lobulares en diferentes configuraciones de las células M de la pared ventricular.Ventricular arrhythmias usually appear as consequence of acute myocardial ischemia, responsible for most of sudden deaths. Functional (different electrical behavior of myocytes as well as biochemical (different ionic concentrations during ischemia cardiac heterogeneity alter the ventricle electric performance and generate dispersion in the action potential repolarization that turns into functional substrate for the generation of fatal arrhythmias. In this work the experimental techniques for the study and detection of arrhythmias by re-entry are reviewed and a geometrical model of ischemia is validated in the presence of electrical heterogeneity in the trans-mural region of the ventricular wall. For this purpose, bi-dimensional simulations of a detailed biophysical model were used and lobular re-entries in different configurations of the M cells of the ventricular wall were obtained.

Energetics and dynamics in organic–inorganic halide perovskite photovoltaics and light emitters

International Nuclear Information System (INIS)

Sum, Tze Chien; Chen, Shi; Xing, Guichuan; Liu, Xinfeng; Wu, Bo

2015-01-01

The rapid transcendence of organic–inorganic metal halide perovskite solar cells to above the 20% efficiency mark has captivated the broad photovoltaic community. As the efficiency race continues unabated, it is essential that fundamental studies keep pace with these developments. Further gains in device efficiencies are expected to be increasingly arduous and harder to come by. The key to driving the perovskite solar cell efficiencies towards their Shockley–Queisser limit is through a clear understanding of the interfacial energetics and dynamics between perovskites and other functional materials in nanostructured- and heterojunction-type devices. In this review, we focus on the current progress in basic characterization studies to elucidate the interfacial energetics (energy-level alignment and band bending) and dynamical processes (from the ultrafast to the ultraslow) in organic–inorganic metal halide perovskite photovoltaics and light emitters. Major findings from these studies will be distilled. Open questions and scientific challenges will also be highlighted. (topical review)

Flecainide Therapy Reduces Exercise-Induced Ventricular Arrhythmias in Patients With Catecholaminergic Polymorphic Ventricular Tachycardia

NARCIS (Netherlands)

van der Werf, Christian; Kannankeril, Prince J.; Sacher, Frederic; Krahn, Andrew D.; Viskin, Sami; Leenhardt, Antoine; Shimizu, Wataru; Sumitomo, Naokata; Fish, Frank A.; Bhuiyan, Zahurul A.; Willems, Albert R.; van der Veen, Maurits J.; Watanabe, Hiroshi; Laborderie, Julien; Haïssaguerre, Michel; Knollmann, Björn C.; Wilde, Arthur A. M.

2011-01-01

Objectives This study evaluated the efficacy and safety of flecainide in addition to conventional drug therapy in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT). Background CPVT is an inherited arrhythmia syndrome caused by gene mutations that destabilize cardiac

A real time ECG signal processing application for arrhythmia detection on portable devices

Science.gov (United States)

Georganis, A.; Doulgeraki, N.; Asvestas, P.

2017-11-01

Arrhythmia describes the disorders of normal heart rate, which, depending on the case, can even be fatal for a patient with severe history of heart disease. The purpose of this work is to develop an application for heart signal visualization, processing and analysis in Android portable devices e.g. Mobile phones, tablets, etc. The application is able to retrieve the signal initially from a file and at a later stage this signal is processed and analysed within the device so that it can be classified according to the features of the arrhythmia. In the processing and analysing stage, different algorithms are included among them the Moving Average and Pan Tompkins algorithm as well as the use of wavelets, in order to extract features and characteristics. At the final stage, testing is performed by simulating our application in real-time records, using the TCP network protocol for communicating the mobile with a simulated signal source. The classification of ECG beat to be processed is performed by neural networks.

Ambulatory cardiac arrhythmias in relation to mild hypokalaemia and prognosis in community dwelling middle-aged and elderly subjects

DEFF Research Database (Denmark)

Mattsson, Nick; Sadjadieh, Golnaz; Kumarathurai, Preman

2016-01-01

with frequency of premature ventricular complexes (PVCs) especially in combination with diuretic treatment (r = -0.22, P = 0.015). Hypokalaemia was not associated with supraventricular arrhythmias. Subjects at lowest quintile of p-potassium (mean 3.42, range 2.7-3.6 mmol/L) were defined as hypokalaemic......, 10 and 15 per 1000 patient-year in those with one abnormality, and 3 per 1000 patient-year in subjects with no abnormality. One variable combining hypokalaemia with excessive supraventricular arrhythmias gave similar results in univariate analysis, but not after multivariate adjustments. CONCLUSION...

Prevention of fatal arrhythmias in high-risk subjects by fish oil n-3 fatty acid intake.

Science.gov (United States)

Leaf, Alexander; Albert, Christine M; Josephson, Mark; Steinhaus, David; Kluger, Jeffrey; Kang, Jing X; Cox, Benjamin; Zhang, Hui; Schoenfeld, David

2005-11-01

The long-chain n-3 fatty acids in fish have been demonstrated to have antiarrhythmic properties in experimental models and to prevent sudden cardiac death in a randomized trial of post-myocardial infarction patients. Therefore, we hypothesized that these n-3 fatty acids might prevent potentially fatal ventricular arrhythmias in high-risk patients. Four hundred two patients with implanted cardioverter/defibrillators (ICDs) were randomly assigned to double-blind treatment with either a fish oil or an olive oil daily supplement for 12 months. The primary end point, time to first ICD event for ventricular tachycardia or fibrillation (VT or VF) confirmed by stored electrograms or death from any cause, was analyzed by intention to treat. Secondary analyses were performed for "probable" ventricular arrhythmias, "on-treatment" analyses for all subjects who had taken any of their oil supplements, and "on-treatment" analyses only of those subjects who were on treatment for at least 11 months. Compliance with double-blind treatment was similar in the 2 groups; however, the noncompliance rate was high (35% of all enrollees). In the primary analysis, assignment to treatment with the fish oil supplement showed a trend toward a prolonged time to the first ICD event (VT or VF) or of death from any cause (risk reduction of 28%; P=0.057). When therapies for probable episodes of VT or VF were included, the risk reduction became significant at 31%; P=0.033. For those who stayed on protocol for at least 11 months, the antiarrhythmic benefit of fish oil was improved for those with confirmed events (risk reduction of 38%; P=0.034). Although significance was not achieved for the primary end point, this study provides evidence that for individuals at high risk of fatal ventricular arrhythmias, regular daily ingestion of fish oil fatty acids may significantly reduce potentially fatal ventricular arrhythmias.

Risk Prediction of One-Year Mortality in Patients with Cardiac Arrhythmias Using Random Survival Forest

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Fen Miao

2015-01-01

Full Text Available Existing models for predicting mortality based on traditional Cox proportional hazard approach (CPH often have low prediction accuracy. This paper aims to develop a clinical risk model with good accuracy for predicting 1-year mortality in cardiac arrhythmias patients using random survival forest (RSF, a robust approach for survival analysis. 10,488 cardiac arrhythmias patients available in the public MIMIC II clinical database were investigated, with 3,452 deaths occurring within 1-year followups. Forty risk factors including demographics and clinical and laboratory information and antiarrhythmic agents were analyzed as potential predictors of all-cause mortality. RSF was adopted to build a comprehensive survival model and a simplified risk model composed of 14 top risk factors. The built comprehensive model achieved a prediction accuracy of 0.81 measured by c-statistic with 10-fold cross validation. The simplified risk model also achieved a good accuracy of 0.799. Both results outperformed traditional CPH (which achieved a c-statistic of 0.733 for the comprehensive model and 0.718 for the simplified model. Moreover, various factors are observed to have nonlinear impact on cardiac arrhythmias prognosis. As a result, RSF based model which took nonlinearity into account significantly outperformed traditional Cox proportional hazard model and has great potential to be a more effective approach for survival analysis.

Energetic map

International Nuclear Information System (INIS)

2012-01-01

This report explains the energetic map of Uruguay as well as the different systems that delimits political frontiers in the region. The electrical system importance is due to the electricity, oil and derived , natural gas, potential study, biofuels, wind and solar energy

Economical aspects of nuclear energetics

International Nuclear Information System (INIS)

Celinski, Z.

2000-01-01

The economical aspects of nuclear power generation in respect to costs of conventional energetics have been discussed in detail. The costs and competitiveness of nuclear power have been considered on the base of worldwide trends taking into account investment and fuel costs as well as 'social' costs being result of impact of different types of energetics on environment, human health etc

Heart rate turbulence and variability in patients with ventricular arrhythmias

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Diego Tarricone

2009-08-01

Full Text Available Background: To evaluate the changes in autonomic neural control mechanisms before malignant ventricular arrhythmias, we measured heart rate variability (HRV and heart rate turbulence (HRT in patients with ventricular tachycardia or fibrillation (Group I; n=6, non sustained ventricular tachycardia (Group II; n=32, frequent premature ventricular beats (Group III; n=26 and with ICD implantation (Group IV; n=11. Methods: Time domain parameters of HRV and turbulence onset (TO and slope (TS were calculated on 24 hour Holter recordings. Normal values were: SDNN > 70 msec for HRV, TO <0% and TS >2.5 msec/RR-I for HRT. Results: Whereas SDNN was within normal range and similar in all study groups, HRT parameters were significantly different in patients who experienced VT/VF during Holter recording. Abnormal TO and/or TS were present in 100% of Group I patients and only in about 50% of Group II and IV. On the contrary, normal HRT parameters were present in 40-70% of Group II, III and IV patients and none of Group I. Conclusions: These data suggest that HRT analysis is more suitable than HRV to detect those transient alterations in autonomic control mechanisms that are likely to play a major trigger role in the genesis of malignant cardiac arrhythmias. (Heart International 2007; 3: 51-7

Energetic Sustainability and the Environment: A Transdisciplinary, Economic–Ecological Approach

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Ioan G. Pop

2017-05-01

Full Text Available The paper combines original concepts about eco-energetic systems, in a transdisciplinary sustainable context. Firstly, it introduces the concept of M.E.N. (Mega-Eco-Nega-Watt, the eco-energetic paradigm based on three different but complementary ecological economic spaces: the Megawatt as needed energy, the Ecowatt as ecological energy, and the Negawatt as preserved energy. The paper also deals with the renewable energies and technologies in the context of electrical energy production. Secondly, in the context of the M.E.N. eco-energetic paradigm, comprehensive definitions are given about eco-energetic systems and for pollution. Thirdly, the paper introduces a new formula for the eco-energetic efficiency which correlates the energetic efficiency of the system and the necessary newly defined ecological coefficient. The proposed formula for eco-energetic efficiency enables an interesting form of relating to different situations in which the input energy, output energy, lost energy, and externalities involved in an energetic process, interact to produce energy in a specific energetic system, in connection with the circular resilient economy model. Finally, the paper presents an original energetic diagram to explain different channels to produce electricity in a resilience regime, with high eco-energetic efficiency from primary external energetic sources (gravitation and solar sources, fuels (classical and radioactive, internal energetic sources (geothermal, volcanoes and other kind of sources. Regardless the kind of energetic sources used to obtain electricity, the entire process should be sustainable in what concerns the transdisciplinary integration of the different representative spheres as energy, socio-economy, and ecology (environment.

Geometric patterns of time-delay plots from different cardiac rhythms and arrhythmias using short-term EKG signals.

Science.gov (United States)

Borracci, Raúl A; Montoya Pulvet, José D; Ingino, Carlos A; Fitz Maurice, Mario; Hirschon Prado, Alfredo; Dominé, Enrique

2017-12-27

To date, no systematic work has been intended to describe spatio-temporal patterns of cardiac rhythms using only short series of RR intervals, to facilitate visual or computerized-aided identification of EKG motifs for use in clinical practice. The aim of this study was to detect and classify eye-catching geometric patterns of Poincaré time-delay plots from different types of cardiac rhythms and arrhythmias using short-term EKG signals. Approximately 150-300 representative, consecutive beats were retrieved from 24-h Holter registers of 100 patients with different heart rhythms. Two-dimensional Poincaré charts were created, and the resulting geometric patterns were transformed into representative familiar eye-catching drawings to interpret different arrhythmias. Poincaré plot representation of RR interval data revealed a wide variety of visual patterns: (i) comet-shaped for sinus rhythm; (ii) torpedo-shaped for sinus bradycardia; (iii) cigarette-shaped for sinus tachycardia; (iv) butterfly-shaped for sinus tachycardia and isolated atrial premature complexes; (v) arrow-shaped for isolated premature complexes and inappropriate sinus tachycardia; (vi) inverted fan-shaped for sinus rhythm with frequent atrial premature complexes; (vii) tornado-shaped for atrial flutter and atrial tachycardia; and (viii) fan-shaped for atrial fibrillation. Modified Poincaré plots with smoothed lines connecting successive points could accurately classify different types of arrhythmias based on short RR interval sequence variability. Characteristic emergent patterns can be visually identified and eventually could be distinguished by an automatic classification system able to discern between arrhythmias. This work provides an alternative method to interpret time-delay plots obtained from short-term EKG signal recordings. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Associations between arrhythmia episodes and temporally and spatially resolved black carbon and particulate matter in elderly patients

Science.gov (United States)

Zanobetti, Antonella; Coull, Brent A.; Gryparis, Alexandros; Kloog, Itai; Sparrow, David; Vokonas, Pantel S; Wright, Robert O.; Gold, Diane R; Schwartz, Joel

2015-01-01

Objectives Ambient air pollution has been associated with sudden deaths, some of which are likely due to ventricular arrhythmias. Defibrillator discharge studies have examined the association of air pollution with arrhythmias in sensitive populations. No studies have assessed this association using residence-specific estimates of air pollution exposure. Methods In the Normative Aging Study, we investigated the association between temporally-and spatially-resolved black carbon (BC) and PM2.5 and arrhythmia episodes (bigeminy, trigeminy or couplets episodes) measured as ventricular ectopy (VE) by 4-min electrocardiogram (ECG) monitoring in repeated measures of 701 subjects, during the years 2000 to 2010. We used a binomial distribution (having or not a VE episode) in a mixed effect model with a random intercept for subject, controlling for seasonality, temperature, day of the week, medication use, smoking, having diabetes, BMI and age. We also examined whether these associations were modified by genotype or phenotype. Results We found significant increases in VE with both pollutants and lags; for the estimated concentration averaged over the three days prior to the health assessment we found increases in the odds of having VE with an OR of 1.52 (95% CI: 1.19–1.94) for an IQR (0.30 μg/m3) increase in BC and an OR of 1.39 (95% CI: 1.12–1.71) for an IQR (5.63 μg/m3) increase in PM2.5. We also found higher effects in subjects with the GSTT1 and GSTM1 variants and in obese (P-valuespollutants may increase the risk of ventricular arrhythmia in elderly subjects. PMID:24142987

Mitochondria, Energetics, Epigenetics, and Cellular Responses to Stress

Science.gov (United States)

McAllister, Kimberly; Worth, Leroy; Haugen, Astrid C.; Meyer, Joel N.; Domann, Frederick E.; Van Houten, Bennett; Mostoslavsky, Raul; Bultman, Scott J.; Baccarelli, Andrea A.; Begley, Thomas J.; Sobol, Robert W.; Hirschey, Matthew D.; Ideker, Trey; Santos, Janine H.; Copeland, William C.; Tice, Raymond R.; Balshaw, David M.; Tyson, Frederick L.

2014-01-01

Background: Cells respond to environmental stressors through several key pathways, including response to reactive oxygen species (ROS), nutrient and ATP sensing, DNA damage response (DDR), and epigenetic alterations. Mitochondria play a central role in these pathways not only through energetics and ATP production but also through metabolites generated in the tricarboxylic acid cycle, as well as mitochondria–nuclear signaling related to mitochondria morphology, biogenesis, fission/fusion, mitophagy, apoptosis, and epigenetic regulation. Objectives: We investigated the concept of bidirectional interactions between mitochondria and cellular pathways in response to environmental stress with a focus on epigenetic regulation, and we examined DNA repair and DDR pathways as examples of biological processes that respond to exogenous insults through changes in homeostasis and altered mitochondrial function. Methods: The National Institute of Environmental Health Sciences sponsored the Workshop on Mitochondria, Energetics, Epigenetics, Environment, and DNA Damage Response on 25–26 March 2013. Here, we summarize key points and ideas emerging from this meeting. Discussion: A more comprehensive understanding of signaling mechanisms (cross-talk) between the mitochondria and nucleus is central to elucidating the integration of mitochondrial functions with other cellular response pathways in modulating the effects of environmental agents. Recent studies have highlighted the importance of mitochondrial functions in epigenetic regulation and DDR with environmental stress. Development and application of novel technologies, enhanced experimental models, and a systems-type research approach will help to discern how environmentally induced mitochondrial dysfunction affects key mechanistic pathways. Conclusions: Understanding mitochondria–cell signaling will provide insight into individual responses to environmental hazards, improving prediction of hazard and susceptibility to

Safer energetic materials by a nanotechnological approach

Science.gov (United States)

Siegert, Benny; Comet, Marc; Spitzer, Denis

2011-09-01

Energetic materials - explosives, thermites, populsive powders - are used in a variety of military and civilian applications. Their mechanical and electrostatic sensitivity is high in many cases, which can lead to accidents during handling and transport. These considerations limit the practical use of some energetic materials despite their good performance. For industrial applications, safety is one of the main criteria for selecting energetic materials. The sensitivity has been regarded as an intrinsic property of a substance for a long time. However, in recent years, several approaches to lower the sensitivity of a given substance, using nanotechnology and materials engineering, have been described. This feature article gives an overview over ways to prepare energetic (nano-)materials with a lower sensitivity.Energetic materials - explosives, thermites, populsive powders - are used in a variety of military and civilian applications. Their mechanical and electrostatic sensitivity is high in many cases, which can lead to accidents during handling and transport. These considerations limit the practical use of some energetic materials despite their good performance. For industrial applications, safety is one of the main criteria for selecting energetic materials. The sensitivity has been regarded as an intrinsic property of a substance for a long time. However, in recent years, several approaches to lower the sensitivity of a given substance, using nanotechnology and materials engineering, have been described. This feature article gives an overview over ways to prepare energetic (nano-)materials with a lower sensitivity. Electronic supplementary information (ESI) available: Experimental details for the preparation of the V2O5@CNF/Al nanothermite; X-ray diffractogram of the V2O5@CNF/Al combustion residue; installation instructions and source code for the nt-timeline program. See DOI: 10.1039/c1nr10292c

Particulate air pollution induces arrhythmia via oxidative stress and calcium calmodulin kinase II activation

Energy Technology Data Exchange (ETDEWEB)

Kim, Jin-Bae [The Division of Cardiology, Kyung Hee University College of Medicine, 1 Hoegi-dong, Dongdaemun-Gu, Seoul (Korea, Republic of); Kim, Changsoo [The Department of Preventive Medicine, Yonsei University College of Medicine, 250 Seungsanno, Seodaemun-gu, Seoul (Korea, Republic of); Choi, Eunmi [Cardiovascular Research Institute and Severance Biomedical Science Institute, Yonsei University College of Medicine, 250 Seungsanno, Seodaemun-gu, Seoul (Korea, Republic of); Park, Sanghoon; Park, Hyelim; Pak, Hui-Nam; Lee, Moon-Hyoung [The Division of Cardiology, Yonsei University College of Medicine, 250 Seungsanno, Seodaemun-gu, Seoul (Korea, Republic of); Shin, Dong Chun [The Department of Preventive Medicine, Yonsei University College of Medicine, 250 Seungsanno, Seodaemun-gu, Seoul (Korea, Republic of); Hwang, Ki-Chul [Cardiovascular Research Institute and Severance Biomedical Science Institute, Yonsei University College of Medicine, 250 Seungsanno, Seodaemun-gu, Seoul (Korea, Republic of); The Division of Cardiology, Yonsei University College of Medicine, 250 Seungsanno, Seodaemun-gu, Seoul (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seungsanno, Seodaemun-gu, Seoul (Korea, Republic of); Joung, Boyoung, E-mail: cby6908@yuhs.ac [The Division of Cardiology, Yonsei University College of Medicine, 250 Seungsanno, Seodaemun-gu, Seoul (Korea, Republic of)

2012-02-15

Ambient particulate matter (PM) can increase the incidence of arrhythmia. However, the arrhythmogenic mechanism of PM is poorly understood. This study investigated the arrhythmogenic mechanism of PM. In Sprague–Dawley rats, QT interval was increased from 115.0 ± 14.0 to 142.1 ± 18.4 ms (p = 0.02) after endotracheal exposure of DEP (200 μg/ml for 30 min, n = 5). Ventricular premature contractions were more frequently observed after DEP exposure (100%) than baseline (20%, p = 0.04). These effects were prevented by pretreatment of N-acetylcysteine (NAC, 5 mmol/L, n = 3). In 12 Langendorff-perfused rat hearts, DEP infusion of 12.5 μg/ml for 20 min prolonged action potential duration (APD) at only left ventricular base increasing apicobasal repolarization gradients. Spontaneous early afterdepolarization (EAD) and ventricular tachycardia (VT) were observed in 8 (67%) and 6 (50%) hearts, respectively, versus no spontaneous triggered activity or VT in any hearts before DEP infusion. DEP-induced APD prolongation, EAD and VT were successfully prevented with NAC (5 mmol/L, n = 5), nifedipine (10 μmol/L, n = 5), and active Ca{sup 2+}/calmodulin-dependent protein kinase II (CaMKII) blockade, KN 93 (1 μmol/L, n = 5), but not by thapsigargin (200 nmol/L) plus ryanodine (10 μmol/L, n = 5) and inactive CaMKII blockade, KN 92 (1 μmol/L, n = 5). In neonatal rat cardiomyocytes, DEP provoked ROS generation in dose dependant manner. DEP (12.5 μg/ml) induced apoptosis, and this effect was prevented by NAC and KN 93. Thus, this study shows that in vivo and vitro exposure of PM induced APD prolongation, EAD and ventricular arrhythmia. These effects might be caused by oxidative stress and CaMKII activation. -- Highlights: ► The ambient PM consistently prolonged repolarization. ► The ambient PM induced triggered activity and ventricular arrhythmia. ► These effects were prevented by antioxidants, I{sub CaL} blockade and CaMKII blockade. ► The ambient PM can induce

Respiratory sinus arrhythmia responses to cognitive tasks : effects of task factors and RSA indices

NARCIS (Netherlands)

Overbeek, T.; Boxtel, van Anton; Westerink, J.H.D.M.

2014-01-01

Many studies show that respiratory sinus arrhythmia (RSA) decreases while performing cognitive tasks. However, there is uncertainty about the role of contaminating factors such as physical activity and stress-inducing task variables. Different methods to quantify RSA may also contribute to variable

Respiratory sinus arrhythmia responses to cognitive tasks: Effects of task factors and RSA indices

NARCIS (Netherlands)

Overbeek, T.J.M.; van Boxtel, A.; Westerink, J.H.D.M.

2014-01-01

Many studies show that respiratory sinus arrhythmia (RSA) decreases while performing cognitive tasks. However, there is uncertainty about the role of contaminating factors such as physical activity and stress-inducing task variables. Different methods to quantify RSA may also contribute to variable

Optimization of some eco-energetic systems

International Nuclear Information System (INIS)

Purica, I.; Pavelescu, M.; Stoica, M.

1976-01-01

An optimization problem of two eco-energetic systems is described. The first one is close to the actual eco-energetic system in Romania, while the second is a new one, based on nuclear energy as primary source and hydrogen energy as secondary source. The optimization problem solved is to find the optimal structure of the systems so that the objective functions adopted, namely unitary energy cost C and total pollution P, to be minimum at the same time. The problem can be modelated with a bimatrix cooperative mathematical game without side payments. We demonstrate the superiority of the new eco-energetic system. (author)

A model of cardiac ryanodine receptor gating predicts experimental Ca2+-dynamics and Ca2+-triggered arrhythmia in the long QT syndrome

Science.gov (United States)

Wilson, Dan; Ermentrout, Bard; Němec, Jan; Salama, Guy

2017-09-01

Abnormal Ca2+ handling is well-established as the trigger of cardiac arrhythmia in catecholaminergic polymorphic ventricular tachycardia and digoxin toxicity, but its role remains controversial in Torsade de Pointes (TdP), the arrhythmia associated with the long QT syndrome (LQTS). Recent experimental results show that early afterdepolarizations (EADs) that initiate TdP are caused by spontaneous (non-voltage-triggered) Ca2+ release from Ca2+-overloaded sarcoplasmic reticulum (SR) rather than the activation of the L-type Ca2+-channel window current. In bradycardia and long QT type 2 (LQT2), a second, non-voltage triggered cytosolic Ca2+ elevation increases gradually in amplitude, occurs before overt voltage instability, and then precedes the rise of EADs. Here, we used a modified Shannon-Puglisi-Bers model of rabbit ventricular myocytes to reproduce experimental Ca2+ dynamics in bradycardia and LQT2. Abnormal systolic Ca2+-oscillations and EADs caused by SR Ca2+-release are reproduced in a modified 0-dimensional model, where 3 gates in series control the ryanodine receptor (RyR2) conductance. Two gates control RyR2 activation and inactivation and sense cytosolic Ca2+ while a third gate senses luminal junctional SR Ca2+. The model predicts EADs in bradycardia and low extracellular [K+] and cessation of SR Ca2+-release terminate salvos of EADs. Ca2+-waves, systolic cell-synchronous Ca2+-release, and multifocal diastolic Ca2+ release seen in subcellular Ca2+-mapping experiments are observed in the 2-dimensional version of the model. These results support the role of SR Ca2+-overload, abnormal SR Ca2+-release, and the subsequent activation of the electrogenic Na+/Ca2+-exchanger as the mechanism of TdP. The model offers new insights into the genesis of cardiac arrhythmia and new therapeutic strategies.

Energetics Laboratory Facilities

Data.gov (United States)

Federal Laboratory Consortium — These energetic materials laboratories are equipped with explosion proof hoods with blow out walls for added safety, that are certified for safe handling of primary...

Mechanisms and Clinical Management of Ventricular Arrhythmias following Blunt Chest Trauma

Directory of Open Access Journals (Sweden)

Daniel H. Wolbrom

2016-01-01

Full Text Available Nonpenetrating, blunt chest trauma is a serious medical condition with varied clinical presentations and implications. This can be the result of a dense projectile during competitive and recreational sports but may also include other etiologies such as motor vehicle accidents or traumatic falls. In this setting, the manifestation of ventricular arrhythmias has been observed both acutely and chronically. This is based on two entirely separate mechanisms and etiologies requiring different treatments. Ventricular fibrillation can occur immediately after chest wall injury (commotio cordis and requires rapid defibrillation. Monomorphic ventricular tachycardia can develop in the chronic stage due to underlying structural heart disease long after blunt chest injury. The associated arrhythmogenic tissue may be complex and provides the necessary substrate to form a reentrant VT circuit. Ventricular tachycardia in the absence of overt structural heart disease appears to be focal in nature with rapid termination during ablation. Regardless of the VT mechanism, patients with recurrent episodes, despite antiarrhythmic medication in the chronic stage following blunt chest injury, are likely to require ablation to achieve VT control. This review article will describe the mechanisms, pathophysiology, and treatment of ventricular arrhythmias that occur in both the acute and chronic stages following blunt chest trauma.

Oxidized CaMKII (Ca2+/Calmodulin-Dependent Protein Kinase II) Is Essential for Ventricular Arrhythmia in a Mouse Model of Duchenne Muscular Dystrophy.

Science.gov (United States)

Wang, Qiongling; Quick, Ann P; Cao, Shuyi; Reynolds, Julia; Chiang, David Y; Beavers, David; Li, Na; Wang, Guoliang; Rodney, George G; Anderson, Mark E; Wehrens, Xander H T

2018-04-01

Duchenne muscular dystrophy patients are prone to ventricular arrhythmias, which may be caused by abnormal calcium (Ca 2+ ) homeostasis and elevated reactive oxygen species. CaMKII (Ca 2+ /calmodulin-dependent protein kinase II) is vital for normal Ca 2+ homeostasis, but excessive CaMKII activity contributes to abnormal Ca 2+ homeostasis and arrhythmias in cardiomyocytes. Reactive oxygen species induce CaMKII to become autonomously active. We hypothesized that genetic inhibition of CaMKII oxidation (ox-CaMKII) in a mouse model of Duchenne muscular dystrophy can alleviate abnormal Ca 2+ homeostasis, thus, preventing ventricular arrhythmia. The objective of this study was to test if selective loss of ox-CaMKII affects ventricular arrhythmias in the mdx mouse model of Duchenne muscular dystrophy. 5-(6)-Chloromethyl-2,7-dichlorodihydrofluorescein diacetate staining revealed increased reactive oxygen species production in ventricular myocytes isolated from mdx mice, which coincides with elevated ventricular ox-CaMKII demonstrated by Western blotting. Genetic inhibition of ox-CaMKII by knockin replacement of the regulatory domain methionines with valines (MM-VV [CaMKII M281/282V]) prevented ventricular tachycardia in mdx mice. Confocal calcium imaging of ventricular myocytes isolated from mdx :MM-VV mice revealed normalization of intracellular Ca 2+ release events compared with cardiomyocytes from mdx mice. Abnormal action potentials assessed by optical mapping in mdx mice were also alleviated by genetic inhibition of ox-CaMKII. Knockout of the NADPH oxidase regulatory subunit p47 phox normalized elevated ox-CaMKII, repaired intracellular Ca 2+ homeostasis, and rescued inducible ventricular arrhythmias in mdx mice. Inhibition of reactive oxygen species or ox-CaMKII protects against proarrhythmic intracellular Ca 2+ handling and prevents ventricular arrhythmia in a mouse model of Duchenne muscular dystrophy. © 2018 American Heart Association, Inc.

Arrhythmias After Tetralogy of Fallot Repair

Science.gov (United States)

Folino, Antonio Franco; Daliento, Luciano

2005-01-01

Tetralogy of Fallot is the most common cyanotic congenital heart disease, with a good outcome after total surgical correction. In spite of a low perioperative mortality and a good quality of life, late sudden death remains a significant clinical problem, mainly related to episodes of sustained ventricular tachycardia and ventricular fibrillation. Fibro-fatty substitution around infundibular resection, intraventricular septal scar, and patchy myocardial fibrosis, may provide anatomical substrates of abnormal depolarization and repolarization causing reentrant ventricular arrhythmias. Several non-invasive indices based on classical examination such as ECG, signal-averaging ECG, and echocardiography have been proposed to identify patients at high risk of sudden death, with hopeful results. In the last years other more sophisticated invasive and non-invasive tools, such as heart rate variability, electroanatomic mapping and cardiac magnetic resonance added a relevant contribution to risk stratification. Even if each method per se is affected by some limitations, a comprehensive multifactorial clinical and investigative examination can provide an accurate risk evaluation for every patient. PMID:16943881

Brief Report: Social Skills, Internalizing and Externalizing Symptoms, and Respiratory Sinus Arrhythmia in Autism

Science.gov (United States)

Neuhaus, Emily; Bernier, Raphael; Beauchaine, Theodore P.

2014-01-01

Theoretical and empirical models describe respiratory sinus arrhythmia (RSA) as a peripheral biomarker of emotion regulation and social competence. Recent findings also link RSA to individual differences in social functioning within autism spectrum disorder (ASD). However, associations between RSA and symptoms of internalizing/externalizing…

Low frequency of cardniac arrhythmias and lack of structural heart disease in medically-naïve acromegaly patients: a prospective study at baseline and after 1 year of somatostatin analogs treatment.

Science.gov (United States)

Warszawski, Leila; Kasuki, Leandro; Sá, Rodrigo; Dos Santos Silva, Cintia Marques; Volschan, Isabela; Gottlieb, Ilan; Pedrosa, Roberto Coury; Gadelha, Mônica R

2016-12-01

The incidence of arrhythmias may be increased in acromegaly, but the pathophysiologic mechanisms involved are still unclear, and it has never been correlated with structural heart changes analyzed by the gold-standard method cardiac magnetic resonance (CMR). Evaluate the frequency of arrhythmias in drug-naïve acromegaly patients at baseline and after 1 year of somatostatin analogs (SA) treatment and to correlate the occurrence of arrhythmias with the presence of structural heart changes. Consecutive drug-naïve acromegaly patients were recruited. The occurrence of arrhythmias and structural heart changes were studied through 24-h Holter and CMR, respectively, at baseline and after 1-year SA treatment. Thirty-six patients were studied at baseline and 28 were re-evaluated after 1 year of SA treatment. There were 13 females and median age was 48 years (20-73 years). Nine patients (32 %) were controlled after treatment. No sustained arrhythmias were reported in the 24-h Holter. No arrhythmia-related symptoms were observed. Only two patients presented left ventricular hypertrophy and three patients presented fibrosis at baseline. There was no correlation of the left ventricular mass with the number of episodes of arrhythmias and they were not more prevalent in the patients presenting cardiac fibrosis. We found no sustained arrhythmias and a lack of arrhythmia-related symptoms at baseline and after 1 year of SA treatment in a contemporary cohort of acromegaly patients that also present a low frequency of structural heart changes, indicating that these patients may have a lower frequency of heart disease than previously reported.

[Silent myocardial ischemia and exercise-induced arrhythmia detected by the exercise test in the total health promotion plan (THP)].

Science.gov (United States)

Iwane, M; Shibe, Y; Itoh, K; Kinoshita, F; Kanagawa, Y; Kobayashi, M; Mugitani, K; Ohta, M; Ohata, H; Yoshikawa, A; Ikuta, Z; Nakamura, Y; Mohara, O

2001-03-01

We investigated the prevalence and characteristics of ischemic heart disease especially silent myocardial ischemia (SMI) and arrhythmia in need of careful observation in the exercise stress tests in the Total Health Promotion Plan (THP), which was conducted between 1994-96 for the purpose of measuring cardiopulmonary function. All workers (n = 4,918, 4,426 males) aged 18-60 yr old in an occupational field were studied. Exercise tests with an ergometer were performed by the LOPS protocol, in which the maximal workload was set up as a presumed 70-80% maximal oxygen intake, or STEP (original multistage protocol). ECG changes were evaluated with a CC5 lead. Two hundred and fifteen people refused the study because of a common cold, lumbago and so on. Of 4,703 subjects, 17 with abnormal rest ECG and 19 with probable anginal pain were excluded from the exercise tests. Of 4,667 who underwent the exercise test, 37 (0.79%) had ischemic ECG change, and 155 (3.32%) had striking arrhythmia. These 228 subjects then did a treadmill exercise test with Bruce protocol. Twenty-two (0.47% of 4,703) showed positive ECG change, 9 (0.19%) of 22 had abnormal findings on a 201Tl scan. 8 (0.17%) were diagnosed as SMI (Cohn I), in which the prevalence of hypertension, hyperlipidemia, diabetes mellitus, smoker and positive familial history of ischemic heart disease was greater than that of all subjects. In a 15-30 month follow up, none has developed cardiac accidents. Exercise-induced arrhythmia was detected in 11 (0.23%) subjects. Four were non-sustained ventricular tachycardia without any organic disease, 4 were ventricular arrhythmia based on cardiomyopathy detected by echocardiography, 2 were atrial fibrillation and another was WPW syndrome. It is therefore likely that the ergometer exercise test in THP was effective in preventing sudden death caused by ischemic heart disease or striking arrhythmia.

Outcome for Fetuses with Prenatally Detected Congenital Heart Disease and Cardiac Arrhythmias in Taiwan

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Sheng-Mou Hsiao

2007-01-01

Conclusion: Outcome for fetuses with prenatally detected CHD remains poor, with the prognosis negatively influenced by the presence of complex heart defects as well as extracardiac and chromosomal anomalies. However, prognosis is good for fetuses with cardiac arrhythmia, except with long QT syndrome or hydrops fetalis.

Atrial Arrhythmias in Obstructive Sleep Apnea: Underlying Mechanisms and Implications in the Clinical Setting

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David Filgueiras-Rama

2013-01-01

Full Text Available Obstructive sleep apnea (OSA is a common disorder characterized by repetitive interruption of ventilation during sleep caused by recurrent upper airway collapse, which leads to intermittent hypoxia. The disorder is commonly undiagnosed despite its relationship with substantial cardiovascular morbidity and mortality. Moreover, the effects of the disorder appear to be particularly dangerous in young subjects. In the last decade, substantial clinical evidence has identified OSA as independent risk factor for both bradyarrhythmias and tachyarrhythmias. To date the mechanisms leading to such arrhythmias have not been completely understood. However, recent data from animal models and new molecular analyses have increased our knowledge of the field, which might lead to future improvement in current therapeutic strategies mainly based on continuous positive airway pressure. This paper aims at providing readers a brief and specific revision of current knowledge about the mechanisms underlying atrial arrhythmias in OSA and their clinical and therapeutic implications.

Rocket measurements of energetic particles in the midlatitude precipitation zone

Science.gov (United States)

Voss, H. D.; Smith, L. G.; Braswell, F. M.

1980-01-01

Measurements of energetic ion and electron properties as a function of altitude in the midlatitude zone of nighttime energetic particle precipitation are reported. The measurements of particle fluxes, energy spectra and pitch angle distributions were obtained by a Langmuir probe, six energetic particle spectrometers and an electrostatic analyzer on board a Nike Apache rocket launched near the center of the midlatitude zone during disturbed conditions. It is found that the incident flux was primarily absorbed rather than backscattered, and consists of mainly energetic hydrogen together with some helium and a small energetic electron component. Observed differential energy spectra of protons having an exponential energy spectrum, and pitch angle distributions at various altitudes indicate that the energetic particle flux decreases rapidly for pitch angles less than 70 deg. An energetic particle energy flux of 0.002 ergs/sq cm per sec is calculated which indicates the significance of energetic particles as a primary nighttime ionization source for altitudes between 120 and 200 km in the midlatitude precipitation zone.

Anxiety and risk of ventricular arrhythmias or mortality in patients with an implantable cardioverter defibrillator

DEFF Research Database (Denmark)

Habibović, Mirela; Pedersen, Susanne S.; van den Broek, Krista C

2013-01-01

A subgroup of patients with an implantable cardioverter defibrillator (ICD) experiences anxiety after device implantation. The purpose of the present study was to evaluate whether anxiety is predictive of ventricular arrhythmias and all-cause mortality 1 year post ICD implantation....

Catheter radiofrequency ablation for arrhythmias under the guidance of the Carto 3 three-dimensional mapping system in an operating room without digital subtraction angiography.

Science.gov (United States)

Huang, Xingfu; Chen, Yanjia; Huang, Zheng; He, Liwei; Liu, Shenrong; Deng, Xiaojiang; Wang, Yongsheng; Li, Rucheng; Xu, Dingli; Peng, Jian

2018-06-01

Several studies have reported the efficacy of a zero-fluoroscopy approach for catheter radiofrequency ablation of arrhythmias in a digital subtraction angiography (DSA) room. However, no reports are available on the ablation of arrhythmias in the absence of DSA in the operating room. To investigate the efficacy and safety of catheter radiofrequency ablation for arrhythmias under the guidance of a Carto 3 three-dimensional (3D) mapping system in an operating room without DSA. Patients were enrolled according to the type of arrhythmia. The Carto 3 mapping system was used to reconstruct heart models and guide the electrophysiologic examination, mapping, and ablation. The total procedure, reconstruction, electrophysiologic examination, and mapping times were recorded. Furthermore, immediate success rates and complications were also recorded. A total of 20 patients were enrolled, including 12 males. The average age was 51.3 ± 17.2 (19-76) years. Nine cases of atrioventricular nodal re-entrant tachycardia, 7 cases of frequent ventricular premature contractions, 3 cases of Wolff-Parkinson-White syndrome, and 1 case of typical atrial flutter were included. All arrhythmias were successfully ablated. The procedure time was 127.0 ± 21.0 (99-177) minutes, the reconstruction time was 6.5 ± 2.9 (3-14) minutes, the electrophysiologic study time was 10.4 ± 3.4 (6-20) minutes, and the mapping time was 11.7 ± 8.3 (3-36) minutes. No complications occurred. Radiofrequency ablation of arrhythmias without DSA is effective and feasible under the guidance of the Carto 3 mapping system. However, the electrophysiology physician must have sufficient experience, and related emergency measures must be present to ensure safety.

Dual Optical Recordings for Action Potentials and Calcium Handling in Induced Pluripotent Stem Cell Models of Cardiac Arrhythmias Using Genetically Encoded Fluorescent Indicators

Science.gov (United States)

Song, LouJin; Awari, Daniel W.; Han, Elizabeth Y.; Uche-Anya, Eugenia; Park, Seon-Hye E.; Yabe, Yoko A.; Chung, Wendy K.

2015-01-01

Reprogramming of human somatic cells to pluripotency has been used to investigate disease mechanisms and to identify potential therapeutics. However, the methods used for reprogramming, in vitro differentiation, and phenotyping are still complicated, expensive, and time-consuming. To address the limitations, we first optimized a protocol for reprogramming of human fibroblasts and keratinocytes into pluripotency using single lipofection and the episomal vectors in a 24-well plate format. This method allowed us to generate multiple lines of integration-free and feeder-free induced pluripotent stem cells (iPSCs) from seven patients with cardiac diseases and three controls. Second, we differentiated human iPSCs derived from patients with Timothy syndrome into cardiomyocytes using a monolayer differentiation method. We found that Timothy syndrome cardiomyocytes showed slower, irregular contractions and abnormal calcium handling compared with the controls. The results are consistent with previous reports using a retroviral method for reprogramming and an embryoid body-based method for cardiac differentiation. Third, we developed an efficient approach for recording the action potentials and calcium transients simultaneously in control and patient cardiomyocytes using genetically encoded fluorescent indicators, ArcLight and R-GECO1. The dual optical recordings enabled us to observe prolonged action potentials and abnormal calcium handling in Timothy syndrome cardiomyocytes. We confirmed that roscovitine rescued the phenotypes in Timothy syndrome cardiomyocytes and that these findings were consistent with previous studies using conventional electrophysiological recordings and calcium imaging with dyes. The approaches using our optimized methods and dual optical recordings will improve iPSC applicability for disease modeling to investigate mechanisms underlying cardiac arrhythmias and to test potential therapeutics. PMID:25769651

Structure of Energetic Particle Mediated Shocks Revisited

International Nuclear Information System (INIS)

Mostafavi, P.; Zank, G. P.; Webb, G. M.

2017-01-01

The structure of collisionless shock waves is often modified by the presence of energetic particles that are not equilibrated with the thermal plasma (such as pickup ions [PUIs] and solar energetic particles [SEPs]). This is relevant to the inner and outer heliosphere and the Very Local Interstellar Medium (VLISM), where observations of shock waves (e.g., in the inner heliosphere) show that both the magnetic field and thermal gas pressure are less than the energetic particle component pressures. Voyager 2 observations revealed that the heliospheric termination shock (HTS) is very broad and mediated by energetic particles. PUIs and SEPs contribute both a collisionless heat flux and a higher-order viscosity. We show that the incorporation of both effects can completely determine the structure of collisionless shocks mediated by energetic ions. Since the reduced form of the PUI-mediated plasma model is structurally identical to the classical cosmic ray two-fluid model, we note that the presence of viscosity, at least formally, eliminates the need for a gas sub-shock in the classical two-fluid model, including in that regime where three are possible. By considering parameters upstream of the HTS, we show that the thermal gas remains relatively cold and the shock is mediated by PUIs. We determine the structure of the weak interstellar shock observed by Voyager 1 . We consider the inclusion of the thermal heat flux and viscosity to address the most general form of an energetic particle-thermal plasma two-fluid model.

Structure of Energetic Particle Mediated Shocks Revisited

Energy Technology Data Exchange (ETDEWEB)

Mostafavi, P.; Zank, G. P. [Department of Space Science, University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Webb, G. M. [Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

2017-05-20

The structure of collisionless shock waves is often modified by the presence of energetic particles that are not equilibrated with the thermal plasma (such as pickup ions [PUIs] and solar energetic particles [SEPs]). This is relevant to the inner and outer heliosphere and the Very Local Interstellar Medium (VLISM), where observations of shock waves (e.g., in the inner heliosphere) show that both the magnetic field and thermal gas pressure are less than the energetic particle component pressures. Voyager 2 observations revealed that the heliospheric termination shock (HTS) is very broad and mediated by energetic particles. PUIs and SEPs contribute both a collisionless heat flux and a higher-order viscosity. We show that the incorporation of both effects can completely determine the structure of collisionless shocks mediated by energetic ions. Since the reduced form of the PUI-mediated plasma model is structurally identical to the classical cosmic ray two-fluid model, we note that the presence of viscosity, at least formally, eliminates the need for a gas sub-shock in the classical two-fluid model, including in that regime where three are possible. By considering parameters upstream of the HTS, we show that the thermal gas remains relatively cold and the shock is mediated by PUIs. We determine the structure of the weak interstellar shock observed by Voyager 1 . We consider the inclusion of the thermal heat flux and viscosity to address the most general form of an energetic particle-thermal plasma two-fluid model.

Energetic consumption levels and human development indexes

International Nuclear Information System (INIS)

Boa Nova, Antonio Carlos

1999-01-01

The article overviews the energetic consumption levels and human development indexes. The human development indexes are described based on the United Nations Development Programme. A comparison between the energetic consumption levels and human development indexes is also presented

A multiprocessor system for the analysis of cardiac arrhythmias

International Nuclear Information System (INIS)

Jugo, G. Diego J.

1983-01-01

The study presented here forms part of a real-time electrocardiographic signal analysis system project. The medical data analysis system consists of eight independent analyser units, all of which are connected to a controller unit by the standard IEEE-488 bus. Each bed is monitored by an arrhythmias analyser which has the facilities for analysing a patient's electrocardiogram automatically in real time. The measurements may be made in the presence of a pacemaker. The system described presents the technique of a separate and a simultaneous data analysis on two different ECG channels. This permit: a better diagnosis and an optimum use of the bus. (author) [fr

Delayed-enhancement MRI of apical hypertrophic cardiomyopathy: assessment of the intramural distribution and comparison with clinical symptoms, ventricular arrhythmias, and cine MRI

International Nuclear Information System (INIS)

Amano, Yasuo; Fukushima, Yoshimitsu; Kumita, Shinichiro; Takayama, Morimasa; Kitamura, Mitsunobu

2011-01-01

Background: Hypertrophic cardiomyopathy (HCM) is reported to show patchy midwall myocardial hyper enhancement on delayed-enhancement magnetic resonance imaging (DE-MRI). The intramural distribution of myocardial hyper enhancement and its correlation with clinical symptoms, ventricular arrhythmias, and cardiac function have not been described for symptomatic apical HCM. Purpose: To evaluate the features and significance of myocardial hyper enhancement on DE-MRI in symptomatic apical HCM. Material and Methods: Thirteen patients with symptomatic apical HCM and their 65 apical segments were investigated. Myocardial hyper enhancement and regional and global functional parameters were determined with MRI. We investigated the intramural distribution and frequencies of this myocardial hyper enhancement and compared them with the patients' clinical symptoms, the presence of ventricular arrhythmias, and cine MRI. Results: Eight (61.5%) patients with symptomatic apical HCM displayed apical myocardial hyper enhancement, and 22 (33.8%) of the 65 apical segments examined showed myocardial hyper enhancement. Of the myocardial hyper enhancement observed, 81.8% showed a subendocardial pattern.The Hyperenhanced apical myocardium had a lower percentage of systolic myocardial thickening, and was associated with serious symptoms (e.g. syncope) and ventricular arrhythmias. Conclusion: Patients with symptomatic apical HCM showed myocardial hyper enhancement involving the subendocardial layer, which might be related to regional systolic dysfunction, serious clinical symptoms, and ventricular arrhythmias

Evidence against the energetic cost hypothesis for the short introns in highly expressed genes

Directory of Open Access Journals (Sweden)

Niu Deng-Ke

2008-05-01

Full Text Available Abstract Background In animals, the moss Physcomitrella patens and the pollen of Arabidopsis thaliana, highly expressed genes have shorter introns than weakly expressed genes. A popular explanation for this is selection for transcription efficiency, which includes two sub-hypotheses: to minimize the energetic cost or to minimize the time cost. Results In an individual human, different organs may differ up to hundreds of times in cell number (for example, a liver versus a hypothalamus. Considered at the individual level, a gene specifically expressed in a large organ is actually transcribed tens or hundreds of times more than a gene with a similar expression level (a measure of mRNA abundance per cell specifically expressed in a small organ. According to the energetic cost hypothesis, the former should have shorter introns than the latter. However, in humans and mice we have not found significant differences in intron length between large-tissue/organ-specific genes and small-tissue/organ-specific genes with similar expression levels. Qualitative estimation shows that the deleterious effect (that is, the energetic burden of long introns in highly expressed genes is too negligible to be efficiently selected against in mammals. Conclusion The short introns in highly expressed genes should not be attributed to energy constraint. We evaluated evidence for the time cost hypothesis and other alternatives.

The relationship between ECG signs of atrial infarction and the development of supraventricular arrhythmias in patients with acute myocardial infarction

DEFF Research Database (Denmark)

Nielsen, F E; Andersen, H H; Gram-Hansen, P

1992-01-01

ECGs obtained on arrival at the hospital from 277 patients with acute myocardial infarction were analyzed retrospectively for PR displacements, which were classified as major or minor criteria for atrial infarction and related to the later occurrence of supraventricular arrhythmia in the hospital...... arrhythmias, giving odds ratios of 9.9 and 3.7, respectively. Enzyme-estimated infarct size, the occurrence of heart failure, and mortality rates did not differ in patients with or without major criteria for atrial infarction. We conclude that the occurrence of PR segment displacements on the admission ECG...

Effects of exogenous oxygen derived free radicals on myocardial capillary permeability, vascular tone, and incidence of ventricular arrhythmias in the canine heart

DEFF Research Database (Denmark)

Svendsen, Jesper Hastrup; Bjerrum, P J

1992-01-01

The aim was to examine the effects of exogenous oxygen derived free radicals on myocardial capillary permeability for a small hydrophilic indicator, postischaemic vascular tone, and the occurrence of arrhythmias in the canine heart in vivo.......The aim was to examine the effects of exogenous oxygen derived free radicals on myocardial capillary permeability for a small hydrophilic indicator, postischaemic vascular tone, and the occurrence of arrhythmias in the canine heart in vivo....

Molecular dynamics calculations of defect energetics in β-SiC

International Nuclear Information System (INIS)

Huang, H.; El-Azab, A.; Ghoniem, N.

1993-01-01

The Molecular Dynamics (MD) method is used to calculate defect energetics in β-silicon carbide. Many-body interaction effects in this covalent material are accounted for by using a hybrid of two-body and three-body potentials. Calculated bulk properties of β-SiC based on this potential are in agreement with experimental data to within 17%. A micro-crystal is constructed to represent the computational cell and external forces are applied to the micro-crystal so that it behaves as a part of an infinite medium. The potential energy for the unperturbed computational cell is first calculated. The cell is then set at a defect configuration and relaxed, and the potential energy of the relaxed cell is calculated. The difference between the potential energy of the unperturbed cell and that of the defect-containing cell is used to calculate the formation and binding energies of point defects, defect clusters and helium-vacancy clusters in SiC

Nonperturbative effects of energetic ions on Alfven eigenmodes

International Nuclear Information System (INIS)

Todo, Y.; Nakajima, N.; Shinohara, K.; Takechi, M.; Ishikawa, M.; Yamamoto, S.

2005-01-01

Linear properties and nonlinear evolutions of an energetic-ion driven instability in a JT-60U plasma were investigated using a simulation code for magnetohydrodynamics and energetic particles. The spatial profile of the unstable mode peaks near the plasma center where the safety factor profile is flat. The unstable mode is not a toroidal Alfven eigenmode (TAE) because the spatial profile deviates from the expected location of TAE and the spatial profile consists of a single primary harmonic m/n = 2/1 where m, n are poloidal and toroidal mode numbers. The real frequency of the unstable mode is close to the experimental starting frequency of the fast frequency sweeping mode. The simulation results demonstrate that the energetic ion orbit width and the energetic ion pressure significantly broaden radial profile of the unstable mode. For the smallest value among the investigated energetic ion orbit width, the unstable mode is localized within 20% of the minor radius. This gives an upper limit of the spatial profile width of the unstable mode which the magnetohydrodynamic effects alone can induce. For the experimental condition of the JT-60U plasma, the energetic ions broaden the spatial profile of the unstable mode by a factor of 3 compared with the smallest orbit width case. The unstable mode is primarily induced by the energetic particles. It is demonstrated that the frequency shifts both upward and downward in the nonlinear evolution at the rate close to that of the fast frequency sweeping mode. In addition to the energetic particle mode in the JT-60U plasma, an investigation of TAE in an LHD-like plasma using the simulation code for the helical coordinate system is reported. (author)

Nonperturbative effects of energetic ions on Alfven eigenmodes

International Nuclear Information System (INIS)

Todo, Y.; Nakajima, N.; Shinohara, Kouji; Takechi, Manabu; Ishikawa, Masao

2005-01-01

Linear properties and nonlinear evolutions of an energetic-ion driven instability in a JT-60U plasma were investigated using a simulation code for magnetohydrodynamics and energetic particles. The spatial profile of the unstable mode peaks near the plasma center where the safety factor profile is flat. The unstable mode is not a toroidal Alfven eigenmode (TAE) because the spatial profile deviates from the expected location of TAE and the spatial profile consists of a single primary harmonic m/n=2/1 where m, n are poloidal and toroidal mode numbers. The real frequency of the unstable mode is close to the experimental starting frequency of the fast frequency sweeping mode. The simulation results demonstrate that the energetic ion orbit width and the energetic ion pressure significantly broaden radial profile of the unstable mode. For the smallest value among the investigated energetic ion orbit width, the unstable mode is localized within 20% of the minor radius. This gives an upper limit of the spatial profile width of the unstable mode which the magnetohydrodynamic effects alone can induce. For the experimental condition of the JT-60U plasma, the energetic ions broaden the spatial profile of the unstable mode by a factor of 3 compared with the smallest orbit width case. The unstable mode is primarily induced by the energetic particles. It is demonstrated that the frequency shifts both upward and downward in the nonlinear evolution at the rate close to that of the fast frequency sweeping mode. In addition to the energetic particle mode in the JT-60U plasma, an investigation of TAE in an LHD-like plasma using the simulation code for the helical coordinate system is reported. (author)

Ecological problems of thermonuclear energetics. Review

Energy Technology Data Exchange (ETDEWEB)

Sivintsev, Yu V

1980-01-01

A review of preliminary quantitative estimates of radiation hazard of thermonuclear reactors is presented. Main attention is given to three aspects: nonradiation effect on environment, radionuclide blow-ups at normal operation and emergency situations with their consequences. The given data testify to great radiological advantages of thermonuclear energetics as compared with the modern nuclear energetics with thermal and prospective fast reactors.

Cost-effectiveness of genotyping in inherited arrhythmia syndromes: are we getting value for the money?

NARCIS (Netherlands)

Wilde, Arthur A. M.; Pinto, Yigal M.

2009-01-01

Over the last decade, the identification of the diverse genetic basis of most important inherited arrhythmia syndromes has remarkably changed our attitude toward these life-threatening diseases. Just over 10 years ago, long-QT syndrome (LQTS) was considered one disease entity, Brugada -QT syndrome

Particulate Air Pollution, Ambulatory Heart Rate Variability, and Cardiac Arrhythmia in Retirement Community Residents with Coronary Artery Disease

Science.gov (United States)

Longhurst, John; Tjoa, Thomas; Sioutas, Constantinos; Delfino, Ralph J.

2013-01-01

Background: Decreased heart rate variability (HRV) has been associated with future cardiac morbidity and mortality and is often used as a marker of altered cardiac autonomic balance in studies of health effects of airborne particulate matter. Fewer studies have evaluated associations between air pollutants and cardiac arrhythmia. Objectives: We examined relationships between cardiac arrhythmias, HRV, and exposures to airborne particulate matter. Methods: We measured HRV and arrhythmia with ambulatory electrocardiograms in a cohort panel study for up to 235 hr per participant among 50 nonsmokers with coronary artery disease who were ≥ 71 years of age and living in four retirement communities in the Los Angeles, California, Air Basin. Exposures included hourly outdoor gases, hourly traffic-related and secondary organic aerosol markers, and daily size-fractionated particle mass. We used repeated measures analyses, adjusting for actigraph-derived physical activity and heart rate, temperature, day of week, season, and community location. Results: Ventricular tachycardia was significantly increased in association with increases in markers of traffic-related particles, secondary organic carbon, and ozone. Few consistent associations were observed for supraventricular tachycardia. Particulates were significantly associated with decreased ambulatory HRV only in the 20 participants using ACE (angiotensin I–converting enzyme) inhibitors. Conclusions: Although these data support the hypothesis that particulate exposures may increase the risk of ventricular tachycardia for elderly people with coronary artery disease, HRV was not associated with exposure in most of our participants. These results are consistent with previous findings in this cohort for systemic inflammation, blood pressure, and ST segment depression. Citation: Bartell SM, Longhurst J, Tjoa T, Sioutas C, Delfino RJ. 2013. Particulate air pollution, ambulatory heart rate variability, and cardiac arrhythmia in

Effect of sodium nitrite on ischaemia and reperfusion-induced arrhythmias in anaesthetized dogs: is protein S-nitrosylation involved?

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Mária Kovács

Full Text Available To provide evidence for the protective role of inorganic nitrite against acute ischaemia and reperfusion-induced ventricular arrhythmias in a large animal model.Dogs, anaesthetized with chloralose and urethane, were administered intravenously with sodium nitrite (0.2 µmol kg(-1 min(-1 in two protocols. In protocol 1 nitrite was infused 10 min prior to and during a 25 min occlusion of the left anterior descending (LAD coronary artery (NaNO2-PO; n = 14, whereas in protocol 2 the infusion was started 10 min prior to reperfusion of the occluded vessel (NaNO2-PR; n = 12. Control dogs (n = 15 were infused with saline and subjected to the same period of ischaemia and reperfusion. Severities of ischaemia and ventricular arrhythmias, as well as changes in plasma nitrate/nitrite (NOx levels in the coronary sinus blood, were assessed throughout the experiment. Myocardial superoxide and nitrotyrosine (NT levels were determined during reperfusion. Changes in protein S-nitrosylation (SNO and S-glutathionylation were also examined.Compared with controls, sodium nitrite administered either pre-occlusion or pre-reperfusion markedly suppressed the number and severity of ventricular arrhythmias during occlusion and increased survival (0% vs. 50 and 92% upon reperfusion. There were also significant decreases in superoxide and NT levels in the nitrite treated dogs. Compared with controls, increased SNO was found only in NaNO2-PR dogs, whereas S-glutathionylation occurred primarily in NaNO2-PO dogs.Intravenous infusion of nitrite profoundly reduced the severity of ventricular arrhythmias resulting from acute ischaemia and reperfusion in anaesthetized dogs. This effect, among several others, may result from an NO-mediated reduction in oxidative stress, perhaps through protein SNO and/or S-glutathionylation.

Excessive exercise habits of runners as new signs of hypertension and arrhythmia.

Science.gov (United States)

Kim, Young-Joo; Kim, Chul-Hyun; Park, Kyoung-Min

2016-08-15

Excessive exercise may induce arrhythmia, and this risk is higher in middle-aged people. The study aim was to compare the exercise characteristics of middle-aged runners participating in excessive endurance exercise. The subjects of this study were 552 runners (mean age; 49.0±7.4years) without structural heart disease who performed exercise at least twice per week, had consistently exercised for at least three years, and had finished at least five marathons. The arrhythmia runner group (ARG, n=14) and normal runner group (NRG, n=538) were compared with regard to hemodynamic response, cardiorespiratory fitness level, training history, number of finished races, finishing times, and exercise habits. The mean resting systolic (134.0±15.8mmHg) and diastolic (85.8±10.9mmHg) blood pressure values indicated pre-hypertension, while the mean maximal SBP (213.7±27.4mmHg) values indicated exercise-induced hypertension. The VO2max was significantly higher and the maximal DBP was significantly lower in the ARG than in the NRG (phypertension and exercise-induced hypertension, and the ARG had higher VO2max values, greater exercise intensities, and longer training histories than the NRG. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Arrhythmias After Tetralogy of Fallot Repair

Directory of Open Access Journals (Sweden)

Antonio Franco Folino

2005-10-01

Full Text Available Tetralogy of Fallot is the most common cyanotic congenital heart disease, with a good outcome after total surgical correction. In spite of a low perioperative mortality and a good quality of life, late sudden death remains a significant clinical problem, mainly related to episodes of sustained ventricular tachycardia and ventricular fibrillation. Fibro-fatty substitution around infundibular resection, intraventricular septal scar, and patchy myocardial fibrosis, may provide anatomical substrates of abnormal depolarization and repolarization causing reentrant ventricular arrhythmias. Several non-invasive indices based on classical examination such as ECG, signal-averaging ECG, and echocardiography have been proposed to identify patients at high risk of sudden death, with hopeful results. In the last years other more sophisticated invasive and non-invasive tools, such as heart rate variability, electroanatomic mapping and cardiac magnetic resonance added a relevant contribution to risk stratification. Even if each method per se is affected by some limitations, a comprehensive multifactorial clinical and investigative examination can provide an accurate risk evaluation for every patient.

10-year follow-up after radiofrequency ablation of idiopathic ventricular arrhythmias from right ventricular outflow tract

Directory of Open Access Journals (Sweden)

Synne Dragesund Rørvik

2016-05-01

Conclusions: A reduction of symptoms and use of antiarrhythmic medication, as well as an improvement in the general health perception and fitness to work after RFA of idiopathic ventricular arrhythmias can be demonstrated at ten-year follow-up.

Segregation and redistribution of end-of-process energetic materials

International Nuclear Information System (INIS)

McCabe, R.A.; Cummins, B.; Gonzalez, M.A.

1993-03-01

A system recovering then recycling or reusing end-of-process energetic materials has been developed at the Lawrence Livermore National Laboratory (LLNL). The system promotes separating energetic materials with high potential for reuse or recycling from those that have no further value. A feature of the system is a computerized electronic bulletin board for advertising the availability of surplus and recovered energetic materials and process chemicals to LLNL researchers, and for posting energetic materials, ''want ads.'' The system was developed and implemented to promote waste minimization and pollution prevention at LLNL

Assessment of accident energetics in LMFBR core-disruptive accidents

International Nuclear Information System (INIS)

Fauske, H.K.

1977-01-01

An assessment of accident energetics in LMFBR core-disruptive accidents is given with emphasis on the generic issues of energetic recriticality and energetic fuel-coolant interaction events. Application of a few general behavior principles to the oxide-fueled system suggests that such events are highly unlikely following a postulated core meltdown event

Identifying potential functional impact of mutations and polymorphisms: Linking heart failure, increased risk of arrhythmias and sudden cardiac death.

Directory of Open Access Journals (Sweden)

BENOIT eJAGU

2013-09-01

Full Text Available Researchers and clinicians have discovered several important concepts regarding the mechanisms responsible for increased risk of arrhythmias, heart failure and sudden cardiac death. One major step in defining the molecular basis of normal and abnormal cardiac electrical behaviour has been the identification of single mutations that greatly increase the risk for arrhythmias and sudden cardiac death by changing channel-gating characteristics. Indeed, mutations in several genes encoding ion channels, such as SCN5A, which encodes the major cardiac Na+ channel, have emerged as the basis for a variety of inherited cardiac arrhythmias such as long QT syndrome, Brugada syndrome, progressive cardiac conduction disorder, sinus node dysfunction or sudden infant death syndrome. In addition, genes encoding ion channel accessory proteins, like anchoring or chaperone proteins, which modify the expression, the regulation of endocytosis and the degradation of ion channel α-subunits have also been reported as susceptibility genes for arrhythmic syndromes. The regulation of ion channel protein expression also depends on a fine-tuned balance among different other mechanisms, such as gene transcription, RNA processing, post-transcriptional control of gene expression by miRNA, protein synthesis, assembly and post-translational modification and trafficking.

Atrial arrhythmia in ageing spontaneously hypertensive rats: unraveling the substrate in hypertension and ageing.

Directory of Open Access Journals (Sweden)

Dennis H Lau

Full Text Available BACKGROUND: Both ageing and hypertension are known risk factors for atrial fibrillation (AF although the pathophysiological contribution or interaction of the individual factors remains poorly understood. Here we aim to delineate the arrhythmogenic atrial substrate in mature spontaneously hypertensive rats (SHR. METHODS: SHR were studied at 12 and 15 months of age (n = 8 per group together with equal numbers of age-matched normotensive Wistar-Kyoto control rats (WKY. Electrophysiologic study was performed on superfused isolated right and left atrial preparations using a custom built high-density multiple-electrode array to determine effective refractory periods (ERP, atrial conduction and atrial arrhythmia inducibility. Tissue specimens were harvested for structural analysis. RESULTS: COMPARED TO WKY CONTROLS, THE SHR DEMONSTRATED: Higher systolic blood pressure (p<0.0001, bi-atrial enlargement (p<0.05, bi-ventricular hypertrophy (p<0.05, lower atrial ERP (p = 0.008, increased atrial conduction heterogeneity (p = 0.001 and increased atrial interstitial fibrosis (p = 0.006 & CD68-positive macrophages infiltration (p<0.0001. These changes resulted in higher atrial arrhythmia inducibility (p = 0.01 and longer induced AF episodes (p = 0.02 in 15-month old SHR. Ageing contributed to incremental bi-atrial hypertrophy (p<0.01 and atrial conduction heterogeneity (p<0.01 without affecting atrial ERP, fibrosis and arrhythmia inducibility. The limited effect of ageing on the atrial substrate may be secondary to the reduction in CD68-positive macrophages. CONCLUSIONS: Significant atrial electrical and structural remodeling is evident in the ageing spontaneously hypertensive rat atria. Concomitant hypertension appears to play a greater pathophysiological role than ageing despite their compounding effect on the atrial substrate. Inflammation is pathophysiologically linked to the pro-fibrotic changes in the hypertensive atria.

Heliospheric Observations of Energetic Particles

Science.gov (United States)

Summerlin, Errol J.

2011-01-01

Heliospheric observations of energetic particles have shown that, on long time averages, a consistent v^-5 power-law index arises even in the absence of transient events. This implies an ubiquitous acceleration process present in the solar wind that is required to generate these power-law tails and maintain them against adiabatic losses and coulomb-collisions which will cool and thermalize the plasma respectively. Though the details of this acceleration process are being debated within the community, most agree that the energy required for these tails comes from fluctuations in the magnetic field which are damped as the energy is transferred to particles. Given this source for the tail, is it then reasonable to assume that the turbulent LISM should give rise to such a power-law tail as well? IBEX observations clearly show a power-law tail of index approximately -5 in energetic neutral atoms. The simplest explanation for the origins of these ENAs are that they are energetic ions which have charge-exchanged with a neutral atom. However, this would imply that energetic ions possess a v^-5 power-law distribution at keV energies at the source of these ENAs. If the source is presumed to be the LISM, it provides additional options for explaining the, so called, IBEX ribbon. This presentation will discuss some of these options as well as potential mechanisms for the generation of a power-law spectrum in the LISM.

Physics of energetic ions

International Nuclear Information System (INIS)

1999-01-01

Physics knowledge (theory and experiment) in energetic particles relevant to design of a reactor scale tokamak is reviewed, and projections for ITER are provided in this Chapter of the ITER Physics Basis. The review includes single particle effects such as classical alpha particle heating and toroidal field ripple loss, as well as collective instabilities that might be generated in ITER plasmas by energetic alpha particles. The overall conclusion is that fusion alpha particles are expected to provide an efficient plasma heating for ignition and sustained burn in the next step device. The major concern is localized heat loads on the plasma facing components produced by alpha particle loss, which might affect their lifetime in a tokamak reactor. (author)

Energetic particle observations at the subsolar magnetopause

Directory of Open Access Journals (Sweden)

A. A. Eccles

Full Text Available The pitch-angle distributions (PAD of energetic particles are examined as the ISEE-1 satellite crosses the Earth’s magnetopause near the subsolar point. The investigation focuses on the possible existence of a particular type of distribution that would be associated with a source of energetic particles in the high-latitude magnetosphere. PADs, demonstrating broad, persistent field-aligned fluxes filling a single hemisphere (upper/northern or lower/southern, were observed just sunward of the magnetopause current layer for an extended period of many minutes. These distributions are a direct prediction of a possible source of energetic particles located in the high altitude dayside cusp and we present five examples in detail of the three-dimensional particle distributions to demonstrate their existence. From these results, other possible causes of such PADs are examined.

Key words. Magnetospheric physics (energetic particles, precipitating; magnetopause, cusp and boundary layers; magnetospheric configuration and dynamics

Energetically resolved multiple-fluid equilibria of tokamak plasmas

International Nuclear Information System (INIS)

Hole, M J; Dennis, G

2009-01-01

In many magnetically confined fusion experiments, a significant fraction of the stored energy of the plasma resides in energetic, or non-thermal, particle populations. Despite this, most equilibrium treatments are based on MHD: a single fluid treatment which assumes a Maxwell-Boltzmann distribution function. Detailed magnetic reconstruction based on this treatment ignore the energetic complexity of the plasma and can result in model-data inconsistencies, such as thermal pressure profiles which are inconsistent with the total stored kinetic energy of the plasma. Alternatively, ad hoc corrections to the pressure profile, such as summing the energetic and thermal pressures, have poor theoretical justification. Motivated by this omission, we generalize ideal MHD one step further: we consider multiple quasi-neutral fluids, each in thermal equilibrium and each thermally insulated from each other-no population mixing occurs. Kinetically, such a model may be able to describe the ion or electron distribution function in regions of velocity phase space with a large number of particles, at the expense of more weakly populated phase space, which may have uncharacteristically high temperature and hence pressure. As magnetic equilibrium effects increase with the increase in pressure, our work constitutes an upper limit to the effect of energetic particles. When implemented into an existing solver, FLOW (Guazzotto et al 2004 Phys. Plasmas 11, 604-14), it becomes possible to qualitatively explore the impact of resolving the energetic populations on plasma equilibrium configurations in realistic geometry. Deploying the modified code, FLOW-M, on a high performance spherical torus configuration, we find that the effect of variations of the pressure, poloidal flow and toroidal flow of the energetic populations is qualitatively similar to variations in the background plasma. We also study the robustness of the equilibrium to uncertainties in the current profile and the energetic

Bile acids induce arrhythmias in human atrial myocardium--implications for altered serum bile acid composition in patients with atrial fibrillation.

Science.gov (United States)

Rainer, Peter P; Primessnig, Uwe; Harenkamp, Sandra; Doleschal, Bernhard; Wallner, Markus; Fauler, Guenter; Stojakovic, Tatjana; Wachter, Rolf; Yates, Ameli; Groschner, Klaus; Trauner, Michael; Pieske, Burkert M; von Lewinski, Dirk

2013-11-01

High bile acid serum concentrations have been implicated in cardiac disease, particularly in arrhythmias. Most data originate from in vitro studies and animal models. We tested the hypotheses that (1) high bile acid concentrations are arrhythmogenic in adult human myocardium, (2) serum bile acid concentrations and composition are altered in patients with atrial fibrillation (AF) and (3) the therapeutically used ursodeoxycholic acid has different effects than other potentially toxic bile acids. Multicellular human atrial preparations ('trabeculae') were exposed to primary bile acids and the incidence of arrhythmic events was assessed. Bile acid concentrations were measured in serum samples from 250 patients and their association with AF and ECG parameters analysed. Additionally, we conducted electrophysiological studies in murine myocytes. Taurocholic acid (TCA) concentration-dependently induced arrhythmias in atrial trabeculae (14/28 at 300 µM TCA, pursodeoxycholic acid did not. Patients with AF had significantly decreased serum levels of ursodeoxycholic acid conjugates and increased levels of non-ursodeoxycholic bile acids. In isolated myocytes, TCA depolarised the resting membrane potential, enhanced Na(+)/Ca(2+) exchanger (NCX) tail current density and induced afterdepolarisations. Inhibition of NCX prevented arrhythmias in atrial trabeculae. High TCA concentrations induce arrhythmias in adult human atria while ursodeoxycholic acid does not. AF is associated with higher serum levels of non-ursodeoxycholic bile acid conjugates and low levels of ursodeoxycholic acid conjugates. These data suggest that higher levels of toxic (arrhythmogenic) and low levels of protective bile acids create a milieu with a decreased arrhythmic threshold and thus may facilitate arrhythmic events.

Effects of dexmedetomidine on heart arrhythmia prevention in off-pump coronary artery bypass surgery: A randomized clinical trial.

Science.gov (United States)

Soltani, Ghasem; Jahanbakhsh, Saeed; Tashnizi, Mohammad Abbasi; Fathi, Mehdi; Amini, Shahram; Zirak, Nahid; Sheybani, Shima

2017-10-01

Arrhythmia occurring during and after surgery is one of the major complications in open-heart surgery. Dexmedetomidine is an intravenous alpha-2 agonist and very specific short-acting drug to protect the various organs against ischemic injuries and blood reflow. However, the effect of dexmedetomidine for preventing intraoperative heart arrhythmias has not been recognized. This study aimed to determine the effect of dexmedetomidine on the incidence rate of heart arrhythmias and anesthetic required in off-pump coronary artery bypass surgery. This randomized clinical trial was conducted on patients who were candidates for off-pump coronary artery bypass referring to Imam Reza Hospital of Mashhad, Iran, from July 2016 through January 2017. The patients were randomly assigned to two groups of intervention (infusion of 0.5 mcg/kg/h dexmedetomidine together with induction followed by infusion of 0.5 mcg/kg/h by the end of the surgery) or control (saline infusion). Mean arterial pressure (MAP) and heart rate (HR) were measured before induction, during surgery operation and ICU admission. Data were analyzed by SPSS version 18 using Chi Square and independent-samples t-test. A total of 76 patients with a mean age of 59.8 ± 8.2 years (in two groups of 38) were studied. The two groups had no statistically significant difference in terms of background variables. The MAP and HR values before induction, during surgery and ICU admission were significantly higher in the control group than in the intervention group (p=0.001). Out of the studied arrhythmias, the values of PAC (55.2% vs. 15.7%), PVC (81.5% vs. 21.0%), AF (26.3% vs. 7.8%), VTAC (21.0% vs. 2.6%) were significantly lower in dexmedetomidine group (p=0.001). It seems that dexmedetomidine administration during induction and surgery can cause significant reduction in most of the common arrhythmias in off-pump coronary bypass surgery. The use of dexmedetomidine maintains MAP and HR at significantly lower values, and changes

Study of energetic-particle-irradiation induced biological effect on Rhizopus oryzae through synchrotron-FTIR micro-spectroscopy

Science.gov (United States)

Liu, Jinghua; Qi, Zeming; Huang, Qing; Wei, Xiaoli; Ke, Zhigang; Fang, Yusheng; Tian, Yangchao; Yu, Zengliang

2013-01-01

Energetic particles exist ubiquitously and cause varied biological effects such as DNA strand breaks, lipid peroxidation, protein modification, cell apoptosis or death. An emerging biotechnology based on ion-beam technique has been developed to serve as an effective tool for mutation breeding of crops and microbes. In order to improve the effectiveness of ion-beam biotechnology for mutation breeding, it is indispensible to gain a better understanding of the mechanism of the interactions between the energetic ions and biological systems which is still elusive. A new trend is to conduct more comprehensive research which is based on micro-scaled observation of the changes of the cellular structures and compositions under the interactions. For this purpose, advanced synchrotron FTIR (s-FTIR) microscopy was employed to monitor the cellular changes of single fungal hyphae under irradiation of α-particles from 241Am. Intracellular contents of ROS, MDA, GSSG/GSH and activities of CAT and SOD were measured via biochemical assay. Ion-irradiation on Rhizopus oryzae causes localized vacuolation, autolysis of cell wall and membrane, lipid peroxidation, DNA damage and conformational changes of proteins, which have been clearly revealed by the s-FTIR microspectroscopy. The different changes of cell viability, SOD and CAT activities can be explained by the ROS-involved chemical reactions. Evidently, the elevated level of ROS in hyphal cells upon irradiation plays the key role in the caused biological effect. This study demonstrates that s-FTIR microspectroscopy is an effective tool to study the damage of fungal hyphae caused by ionizing radiation and it facilitates the exploit of the mechanism for the interactions between the energetic ions and biological systems.

Ventricular arrhythmias and sudden cardiac arrest in Takotsubo cardiomyopathy: Incidence, predictive factors, and clinical implications.

Science.gov (United States)

Jesel, Laurence; Berthon, Charlotte; Messas, Nathan; Lim, Han S; Girardey, Mélanie; Marzak, Halim; Marchandot, Benjamin; Trinh, Annie; Ohlmann, Patrick; Morel, Olivier

2018-04-06

Takotsubo cardiomyopathy (TTC) is a stress-related transient cardiomyopathy. Life-threatening arrhythmias (LTA) can occur and worsen prognosis. The purpose of this study was to assess the incidence and outcome of LTA in TTC, as well as its predictive factors and clinical implications. We studied 214 consecutive cases of TTC over 8 years. The study cohort was divided into 2 groups: those with LTA (LTA group) and those without (non-LTA group). LTA was defined as ventricular tachycardia, ventricular fibrillation, or cardiac arrest. LTA occurred in 10.7% of patients mainly in the first 24 hours of hospitalization: ventricular tachycardia (n = 2), ventricular fibrillation (n = 11), cardiac arrest (n = 10: 5 asystole, 3 complete heart block, and 2 sinoatrial block). LTA were associated with lower left ventricular ejection fraction (LVEF) and a high rate of conduction disturbances. In-hospital (39.1% vs 8.9%; P 105 ms were independent predictors of LTA. In cases where a device was implanted, conduction disturbances persisted after the index event despite complete recovery of LVEF. There was no ventricular arrhythmia recurrence during follow-up. LTA occur early in patients presenting with TTC and is associated with significantly worse short- and long-term prognosis. Left ventricular impairment and QRS duration >105 ms are independent predictors of LTA. Ventricular arrhythmias occurred in the acute phase without further recurrence recorded in hospital survivors, whereas severe conduction disorders persisted during long-term follow-up. These findings may have implications on the choice of device therapy for this specific patient subgroup. Copyright © 2018 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Energetic policies 2005-2030

International Nuclear Information System (INIS)

2008-01-01

This power point exhibition shows the following topics: energy analysis, production and use, supply and demand, consumption, energy sources, energetic prospective of Uruguay country, medium and long term perspectives.

Cardiac arrhythmias during aerobatic flight and its simulation on a centrifuge.

Science.gov (United States)

Zawadzka-Bartczak, Ewelina K; Kopka, Lech H

2011-06-01

It is well known that accelerations during centrifuge training and during flight can provoke cardiac arrhythmias. Our study was designed to investigate both the similarities and differences between heart rhythm disturbances during flights and centrifuge tests. There were 40 asymptomatic, healthy pilots who performed two training flights and were also tested in a human centrifuge according to a program of rapid onset rate acceleration (ROR) and of centrifuge simulation of the actual acceleration experienced in flight (Simulation). During the flight and centrifuge tests ECG was monitored with the Holter method. ECG was examined for heart rhythm changes and disturbances. During flights, premature ventricular contractions (PVCs) were found in 25% of the subjects, premature supraventricular contractions (PSVCs) and PVCs with bigeminy in 5%, and pairs of PVCs in 2.5% of subjects. During the centrifuge tests, PVCs were experienced by 45% of the subjects, PSVCs and pairs of PVCs by 7.5%, and PVCs with bigeminy by 2.5%. Sinus bradycardia was observed during flights and centrifuge tests in 7.5% of subjects. Comparative evaluation of electrocardiographic records in military pilots during flights and centrifuge tests demonstrated that: 1) there were no clinically significant arrhythmias recorded; and 2) the frequency and kind of heart rhythm disturbances during aerobatic flight and its simulation on a centrifuge were not identical and did not occur repetitively in the same persons during equal phases of the tests.

Advances in magnetospheric physics, 1971--1974: energetic particles

International Nuclear Information System (INIS)

West, H.I. Jr.

1974-12-01

An account is given of energetic particle research in magnetospheric physics for the time period 1971--1974. Emphasis is on relating the various aspects of energetic particles to magnetospheric processes. 458 refs. (U.S.)

Sol-Gel Manufactured Energetic Materials

Science.gov (United States)

Simpson, Randall L.; Lee, Ronald S.; Tillotson, Thomas M.; Hrubesh, Lawrence W.; Swansiger, Rosalind W.; Fox, Glenn A.

2005-05-17

Sol-gel chemistry is used for the preparation of energetic materials (explosives, propellants and pyrotechnics) with improved homogeneity, and/or which can be cast to near-net shape, and/or made into precision molding powders. The sol-gel method is a synthetic chemical process where reactive monomers are mixed into a solution, polymerization occurs leading to a highly cross-linked three dimensional solid network resulting in a gel. The energetic materials can be incorporated during the formation of the solution or during the gel stage of the process. The composition, pore, and primary particle sizes, gel time, surface areas, and density may be tailored and controlled by the solution chemistry. The gel is then dried using supercritical extraction to produce a highly porous low density aerogel or by controlled slow evaporation to produce a xerogel. Applying stress during the extraction phase can result in high density materials. Thus, the sol-gel method can be used for precision detonator explosive manufacturing as well as producing precision explosives, propellants, and pyrotechnics, along with high power composite energetic materials.

Energetic materials: crystallization, characterization and insensitive plastic bonded explosives

Energy Technology Data Exchange (ETDEWEB)

Heijden, Antoine E.D.M. van der; Creyghton, Yves L.M.; Marino, Emanuela; Bouma, Richard H.B.; Scholtes, Gert J.H.G.; Duvalois, Willem [TNO Defence, Security and Safety, P. O. Box 45, 2280 AA Rijswijk (Netherlands); Roelands, Marc C.P.M. [TNO Science and Industry, P. O. Box 342, 7300 AH Apeldoorn (Netherlands)

2008-02-15

The product quality of energetic materials is predominantly determined by the crystallization process applied to produce these materials. It has been demonstrated in the past that the higher the product quality of the solid energetic ingredients, the less sensitive a plastic bonded explosive containing these energetic materials becomes. The application of submicron or nanometric energetic materials is generally considered to further decrease the sensitiveness of explosives. In order to assess the product quality of energetic materials, a range of analytical techniques is available. Recent attempts within the Reduced-sensitivity RDX Round Robin (R4) have provided the EM community a better insight into these analytical techniques and in some cases a correlation between product quality and shock initiation of plastic bonded explosives containing (RS-)RDX was identified, which would provide a possibility to discriminate between conventional and reduced sensitivity grades. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

Energetic matrix of Rio de Janeiro State, Brazil - 1994/2004

International Nuclear Information System (INIS)

1996-01-01

This book has been structured into three parts and three appendices. In the first part, named Energetic matrix of Rio de Janeiro State, the most important economic and social aspects of the State and the methodology for elaboration of economic and energetic scenarios has been detailed. In the second part, an analysis of seven consumption sectors components of the energetic matrix structure ( industrial, transports, residential, commercial, energetic, agriculture and cattle-breeding, non energetic) has been performed, with the objective of providing information on the present status and future prospects of energy consumption by sectors up to 2004. Finally, in the third part, the energy supply of Rio de Janeiro State for the consumption sectors has been discussed

Remote ischemic preconditioning differentially attenuates post-ischemic cardiac arrhythmia in streptozotocin-induced diabetic versus nondiabetic rats.

Science.gov (United States)

Hu, Zhaoyang; Chen, Mou; Zhang, Ping; Liu, Jin; Abbott, Geoffrey W

2017-04-26

Sudden cardiac death (SCD), a leading cause of global mortality, most commonly arises from a substrate of cardiac ischemia, but requires an additional trigger. Diabetes mellitus (DM) predisposes to SCD even after adjusting for other DM-linked cardiovascular pathology such as coronary artery disease. We previously showed that remote liver ischemia preconditioning (RLIPC) is highly protective against cardiac ischemia reperfusion injury (IRI) linked ventricular arrhythmias and myocardial infarction, via induction of the cardioprotective RISK pathway, and specifically, inhibitory phosphorylation of GSK-3β (Ser 9). We evaluated the impact of acute streptozotocin-induced DM on coronary artery ligation IRI-linked ventricular arrhythmogenesis and RLIPC therapy in rats. Post-IRI arrhythmia induction was similar in nondiabetic and DM rats, but, unexpectedly, DM rats exhibited lower incidence of SCD during reperfusion (41 vs. 100%), suggesting uncontrolled hyperglycemia does not acutely predispose to SCD. RLIPC was highly effective in both nondiabetic and DM rats at reducing incidence and duration of, and increasing latency to, all classes of ventricular tachyarrhythmias. In contrast, atrioventricular block (AVB) was highly responsive to RLIPC in nondiabetic rats (incidence reduced from 72 to 18%) but unresponsive in DM rats. RISK pathway induction was similar in nondiabetic and DM rats, thus not explaining the DM-specific resistance of AVB to therapy. Our findings uncover important acute DM-specific differences in responsiveness to remote preconditioning for ventricular tachyarrhythmias versus AVB, which may have clinical significance given that AVB is a malignant arrhythmia twofold more common in human diabetics than nondiabetics, and correlated to plasma glucose levels >10 mmol/L.

Determination of myocardial energetic output for cardiac rhythm pacing

Czech Academy of Sciences Publication Activity Database

Heřman, D.; Převorovská, Světlana; Maršík, František

2007-01-01

Roč. 7, č. 4 (2007), s. 156-161 ISSN 1567-8822 R&D Projects: GA ČR GA106/03/1073 Institutional research plan: CEZ:AV0Z20760514 Keywords : heart arrhythmia * cardiac pacing modes * numerical simulation Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery

Effect of low oral doses of disopyramide and amiodarone on ventricular and atrial arrhythmias of chagasic patients with advanced myocardial damage.

Science.gov (United States)

Carrasco, H A; Vicuña, A V; Molina, C; Landaeta, A; Reynosa, J; Vicuña, N; Fuenmayor, A; López, F

1985-12-01

Low-dose (7 mg/kg per day) disopyramide administration to arrhythmic chagasic patients decreased the frequency of ventricular extrasystoles in 4 of 17 patients (24%) and suppressed most complex ventricular arrhythmias in 12 of 15 patients (80%). This assessment was made from 72-h continuous Holter monitoring recorded during the course of this double blind, placebo-controlled randomized crossover study. Seven patients (41%) complained of anticholinergic side effects, but no contractile or conduction system depression was seen. Amiodarone (200 mg) given on a single blind, placebo-controlled basis to 9 of these patients reduced the frequency of ventricular extrasystoles in 6 of 9 patients (67%) and suppressed complex ventricular ectopy in 6 of 7 patients (85%). One patient was unable to tolerate this drug (11%). Both drugs seemed less effective in controlling supraventricular arrhythmias, although disopyramide eliminated paroxysms of supraventricular tachycardia in 9 of 13 (69%) and amiodarone in all 6 patients with this arrhythmia. Amiodarone appears to be a better antiarrhythmic drug for chagasic patients, due to its greater effectiveness and lower incidence of side effects.

Energetic magnetospheric protons in the plasma depletion layer

International Nuclear Information System (INIS)

Fuselier, S.A.

1992-01-01

Interplanetary magnetic field draping against the Earth's dayside subsolar magnetopause creates a region of reduced plasma density and increased magnetic field called the plasma depletion layer. In this region, leakage of energetic ions from the Earth's magnetosphere onto magnetic field lines in the plasma depletion layer can be studied without interference from ions accelerated at the Earth's quasi-parallel bow shock. Active Magnetospheric Particle Tracer Experiment/Charge Composition Explorer (AMPTE/CCE) observations for 13 plasma depletion layer events are used to determine the characteristics of energetic protons between a few keV/e and ∼100keV/e leaked from the magnetosphere. Results indicate that the leaked proton distributions resemble those in the magnetosphere except that they have lower densities and temperatures and much higher velocities parallel (or antiparallel) and perpendicular to the magnetic field. Compared to the low-energy magnetosheath proton distributions present in the depletion layer, the leaked energetic proton distributions typically have substantially higher flow velocities along the magnetic field indicate that the leaked energetic proton distributions to contribute to the energetic proton population seen upstream and downstream from the quasi-parallel bow shock. However, their contribution is small compared to the contribution from acceleration of protons at the bow shock because the leaked proton densities are on the order of 10 times smaller than the energetic proton densities typically observed in the vicinity of the quasi-parallel bow shock

Automated system for ST segment and arrhythmia analysis in exercise radionuclide ventriculography

International Nuclear Information System (INIS)

Hsia, P.W.; Jenkins, J.M.; Shimoni, Y.; Gage, K.P.; Santinga, J.T.; Pitt, B.

1986-01-01

A computer-based system for interpretation of the electrocardiogram (ECG) in the diagnosis of arrhythmia and ST segment abnormality in an exercise system is presented. The system was designed for inclusion in a gamma camera so the ECG diagnosis could be combined with the diagnostic capability of radionuclide ventriculography. Digitized data are analyzed in a beat-by-beat mode and a contextual diagnosis of underlying rhythm is provided. Each beat is assigned a beat code based on a combination of waveform analysis and RR interval measurement. The waveform analysis employs a new correlation coefficient formula which corrects for baseline wander. Selective signal averaging, in which only normal beats are included, is done for an improved signal-to-noise ratio prior to ST segment analysis. Template generation, R wave detection, QRS window size, baseline correction, and continuous updating of heart rate have all been automated. ST level and slope measurements are computed on signal-averaged data. Arrhythmia analysis of 13 passages of abnormal rhythm by computer was found to be correct in 98.4 percent of all beats. 25 passages of exercise data, 1-5 min in length, were evaluated by the cardiologist and found to be in agreement in 95.8 percent in measurements of ST level and 91.7 percent in measurements of ST slope

Intracardiac echo-facilitated 3D electroanatomical mapping of ventricular arrhythmias from the papillary muscles: assessing the 'fourth dimension' during ablation.

Science.gov (United States)

Proietti, Riccardo; Rivera, Santiago; Dussault, Charles; Essebag, Vidal; Bernier, Martin L; Ayala-Paredes, Felix; Badra-Verdu, Mariano; Roux, Jean-François

2017-01-01

Ventricular arrhythmias (VA) originating from a papillary muscle (PM) have recently been described as a distinct clinical entity with peculiar features that make its treatment with catheter ablation challenging. Here, we report our experience using an intracardiac echo-facilitated 3D electroanatomical mapping approach in a case series of patients undergoing ablation for PM VA. Sixteen patients who underwent catheter ablation for ventricular tachycardia (VT) or symptomatic premature ventricular contractions originating from left ventricular PMs were included in the study. A total of 24 procedures (mean 1.5 per patient) were performed: 15 using a retrograde aortic approach and 9 using a transseptal approach. Integrated intracardiac ultrasound for 3D electroanatomical mapping was used in 15 of the 24 procedures. The posteromedial PM was the most frequent culprit for the clinical arrhythmia, and the body was the part of the PM most likely to be the successful site for ablation. The site of ablation was identified based on the best pace map matching the clinical arrhythmia and the site of earliest the activation. At a mean follow-up of 10.5 ± 7 months, only two patients had recurrent arrhythmias following a repeat ablation procedure. An echo-facilitated 3D electroanatomical mapping allows for real-time creation of precise geometries of cardiac chambers and endocavitary structures. This is useful during procedures such as catheter ablation of VAs originating from PMs, which require detailed representation of anatomical landmarks. Routine adoption of this technique should be considered to improve outcomes of PM VA ablation. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

Serious arrhythmias in patients with apical hypertrophic cardiomyopathy

Energy Technology Data Exchange (ETDEWEB)

Okishige, Kaoru; Sasano, Tetsuo; Yano, Kei; Azegami, Kouji; Suzuki, Kou; Itoh, Kuniyasu [Yokohama Red Cross Hospital (Japan)

2001-05-01

We report cases of serious arrhythmias associated with apical hypertrophic cardiomyopathy (AHCM). Thirty-one patients were referred to our institute to undergo further assessment of their AHCM from 1988 to 1999. Three patients with nonsustained ventricular tachycardia demonstrated an {sup 123}I-MIBG regional reduction in the tracer uptake. In two patients with ventricular fibrillation (VF), the findings from {sup 123}I-MIBG imaging revealed regional sympathetic denervation in the inferior and lateral regions. Electrophysiologic study demonstrated reproducible induction of VF in aborted sudden death and presyncopal patients, resulting in the need for an implantable defibrillator device and amiodarone in each patient. Patients with refractory atrial fibrillation with a rapid ventricular response suffered from serious congestive heart failure. A prudent assessment and strategy in patients with this disease would be indispensable in avoiding a disastrous outcome. (author)

Nonpharmacologic control of postoperative supraventricular arrhythmias using AV nodal fat pad stimulation in a young animal open heart surgical model.

Science.gov (United States)

Moak, Jeffrey P; Mercader, Marco A; He, Dingchao; Trachiotis, Gregory; Langert, Joshua; Blicharz, Andy; Montaque, Erin; Li, Xiyan; Cheng, Yao I; McCarter, Robert; Bornzin, Gene A; Martin, Gerard R; Jonas, Richard A

2013-06-01

Supraventricular arrhythmias (junctional ectopic tachycardia [JET] and atrial tachyarrhythmias) frequently complicate recovery from open heart surgery in children and can be difficult to manage. Medical treatment of JET can result in significant morbidity. Our goal was to develop a nonpharmacological approach using autonomic stimulation of selective fat pad (FP) regions of the heart in a young canine model of open heart surgery to control 2 common postoperative supraventricular arrhythmias. Eight mongrel dogs, varying in age from 5 to 8 months and weighting 22±4 kg, underwent open heart surgery replicating a nontransannular approach to tetralogy of Fallot repair. Neural stimulation of the right inferior FP was used to control the ventricular response to supraventricular arrhythmias. Right inferior FP stimulation decreased baseline AV nodal conduction without altering sinus cycle length. AV node Wenckebach cycle length prolonged from 270±33 to 352±89 ms, P=0.02. Atrial fibrillation occurred in 7 animals, simulating a rapid atrial tachyarrhythmias. FP stimulation slowed the ventricular response rate from 166±58 to 63±29 beats per minute, Popen heart surgery model. FP stimulation may be a useful new technique for managing children with JET and atrial tachyarrhythmias.

Cutting and machining energetic materials with a femtosecond laser

Energy Technology Data Exchange (ETDEWEB)

Roeske, Frank; Benterou, Jerry; Lee, Ronald; Roos, Edward [Energetic Materials Center, Lawrence Livermore National Laboratory, P. O. Box 808, Livermore, CA 94550 (United States)

2003-04-01

A femtosecond (fs) laser has been used as a tool for solving many problems involving access, machining, disassembly, inspection and avoidance of undesirable hazardous waste streams in systems containing energetic materials. Because of the unique properties of the interaction of ultrashort laser pulses with matter, the femtosecond laser can be used to safely cut these energetic materials in a precise manner without creating an unacceptable waste stream. Many types of secondary high explosives (HE) and propellants have been cut with the laser for a variety of applications ranging from disassembly of aging conventional weapons (demilitarization), inspection of energetic components of aging systems to creating unique shapes of HE for purposes of initiation and detonation physics studies. Hundreds of samples of energetic materials have been cut with the fs laser without ignition and, in most cases, without changing the surface morphology of the cut surfaces. The laser has also been useful in cutting nonenergetic components in close proximity to energetic materials. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

European Heart Rhythm Association (EHRA) position paper on arrhythmia management and device therapies in endocrine disorders, endorsed by Asia Pacific Heart Rhythm Society (APHRS) and Latin American Heart Rhythm Society (LAHRS).

Science.gov (United States)

Gorenek, Bulent; Boriani, Giuseppe; Dan, Gheorge-Andrei; Fauchier, Laurent; Fenelon, Guilherme; Huang, He; Kudaiberdieva, Gulmira; Lip, Gregory Y H; Mahajan, Rajiv; Potpara, Tatjana; Ramirez, Juan David; Vos, Marc A; Marin, Francisco

2018-03-16

Endocrine disorders are associated with various tachyarrhythmias, including atrial fibrillation (AF), ventricular tachycardia (VT), ventricular fibrillation (VF), and bradyarrhythmias. Along with underlying arrhythmia substrate, electrolyte disturbances, glucose, and hormone levels, accompanying endocrine disorders contribute to development of arrhythmia. Arrhythmias may be life-threatening, facilitate cardiogenic shock development and increase mortality. The knowledge on the incidence of tachy- and bradyarrhythmias, clinical and prognostic significance as well as their management is limited; it is represented in observational studies and mostly in case reports on management of challenging cases. It should be also emphasized, that the topic is not covered in detail in current guidelines. Therefore, cardiologists and multidisciplinary teams participating in care of such patients do need the evidence-based, or in case of limited evidence expert-opinion based recommendations, how to treat arrhythmias using contemporary approaches, prevent their complications and recurrence in patients with endocrine disorders. In recognizing this close relationship between endocrine disorders and arrhythmias, the European Heart Rhythm Association (EHRA) convened a Task Force, with representation from Asia-Pacific Heart Rhythm Society (APHRS) and Sociedad Latinoamericana de Estimulación Cardíaca y Electrofisiología (SOLAECE), with the remit of comprehensively reviewing the available evidence and publishing a joint consensus document on endocrine disorders and cardiac arrhythmias, and providing up-to-date consensus recommendations for use in clinical practice.

Energetic particle physics with applications in fusion and space plasmas

International Nuclear Information System (INIS)

Cheng, C.Z.

1997-01-01

Energetic particle physics is the study of the effects of energetic particles on collective electromagnetic (EM) instabilities and energetic particle transport in plasmas. Anomalously large energetic particle transport is often caused by low frequency MHD instabilities, which are driven by these energetic particles in the presence of a much denser background of thermal particles. The theory of collective energetic particle phenomena studies complex wave-particle interactions in which particle kinetic physics involving small spatial and fast temporal scales can strongly affect the MHD structure and long-time behavior of plasmas. The difficulty of modeling kinetic-MHD multiscale coupling processes stems from the disparate scales which are traditionally analyzed separately: the macroscale MHD phenomena are studied using the fluid MHD framework, while microscale kinetic phenomena are best described by complicated kinetic theories. The authors have developed a kinetic-MHD model that properly incorporates major particle kinetic effects into the MHD fluid description. For tokamak plasmas a nonvariational kinetic-MHD stability code, the NOVA-K code, has been successfully developed and applied to study problems such as the excitation of fishbone and Toroidal Alfven Eigenmodes (TAE) and the sawtooth stabilization by energetic ions in tokamaks. In space plasmas the authors have employed the kinetic-MHD model to study the energetic particle effects on the ballooning-mirror instability which explains the multisatellite observation of the stability and field-aligned structure of compressional Pc 5 waves in the magnetospheric ring current plasma

Inflammation markers are associated with metabolic syndrome and ventricular arrhythmia in patients with coronary artery disease

Directory of Open Access Journals (Sweden)

Krzysztof Safranow

2016-02-01

previous studies have suggested that the inflammatory process plays an important role in generation of cardiac arrhythmia, but the majority of these reports concerned atrial fibrillation (AF [28]. These findings are supported by experimental studies, since atrial biopsies taken from patients with AF compared with controls have demonstrated evidence of inflammatory infiltrates and oxidative damage within the atrial tissue [10]. Inflammation and oxidative injury directly affect atrial myocyte contraction, electrical conduction, myocyte apoptosis, and cardiac fibrosis [39]. CRP can induce AF, causing the disarray of normal cell membrane structure by interaction with lysophospholipids followed by activation of the complement system and phagocytosis [35]. Our results did not show an association of AF with inflammation markers, but there were only 9 patients with AF in our study group. Similar mechanisms may be involved in the generation of ventricular arrhythmia. Moreover, inflammatory biomarkers can transform a stable atherosclerotic plaque into an unstable lesion, leading to ischemia-induced ventricular arrhythmias and sudden cardiac death events [40]. In the study of Albert et al., higher CRP levels were independently associated with an increased risk of sudden cardiac death over a 17-year follow-up period [2]. In another study, frequent premature ventricular contractions together with high CRP were associated with higher risk of death and acute myocardial infarction [50]. High peak serum CRP was an independent predictor of VT/VF in STEMI patients treated with primary percutaneous coronary intervention, while WBC was also significantly higher in patients with VT/VF [33]. High serum CRP was an independent predictor of VT/VF or cardiac death after ICD implantation [58]. In another study, increased CRP was an independent predictor of VT in ICD recipients after myocardial infarction [7]. Elevated preimplantation hs-CRP serum level was independently associated with increased

Anti-addiction Drug Ibogaine Prolongs the Action Potential in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes.

Science.gov (United States)

Rubi, Lena; Eckert, Daniel; Boehm, Stefan; Hilber, Karlheinz; Koenig, Xaver

2017-04-01

Ibogaine is a plant alkaloid used as anti-addiction drug in dozens of alternative medicine clinics worldwide. Recently, alarming reports of life-threatening cardiac arrhythmias and cases of sudden death associated with the ingestion of ibogaine have accumulated. Using whole-cell patch clamp recordings, we assessed the effects of ibogaine and its main metabolite noribogaine on action potentials in human ventricular-like cardiomyocytes derived from induced pluripotent stem cells. Therapeutic concentrations of ibogaine and its long-lived active metabolite noribogaine significantly retarded action potential repolarization in human cardiomyocytes. These findings represent the first experimental proof that ibogaine application entails a cardiac arrhythmia risk for humans. In addition, they explain the clinically observed delayed incidence of cardiac adverse events several days after ibogaine intake. We conclude that therapeutic concentrations of ibogaine retard action potential repolarization in the human heart. This may give rise to a prolongation of the QT interval in the electrocardiogram and cardiac arrhythmias.

Feasibility and accuracy of a new mobile electrocardiography device, ER-2000®, in the diagnosis of arrhythmia

Directory of Open Access Journals (Sweden)

Yae Min Park

2015-08-01

Conclusions: A rhythm strip obtained using ER-2000® is accurate in diagnosing arrhythmia, despite some differences in the detailed morphology of the QRS and T-wave, and the pacing spike compared to those obtained by the 12-lead ECG.

Neoclassical transport of energetic beam ions in the Large Helical Device

International Nuclear Information System (INIS)

Murakami, Sadayoshi; Yamada, Hiroshi; Kaneko, Osamu

2000-01-01

The neoclassical (collisional) transport of energetic ions is investigated by the global neoclassical transport simulation in the Large Helical Device (LHD). The steady state distributions of energetic ions are evaluated assuming an energetic particle source by NBI heating (tangentally injected). Significant radial transport of energetic ions can be seen due to the radial motion of trapped particles in the velocity region below near critical velocity. Our simulation results show relatively good agreements with the experimental results of fast particle measurements in the LHD. This suggests an important role of neoclassical transport in the radial transport process of energetic ions in heliotrons. (author)

Life cycles of energetic systems

International Nuclear Information System (INIS)

Adnot, Jerome; Marchio, Dominique; Riviere, Philippe; Duplessis, B.; Rabl, A.; Glachant, M.; Aggeri, F.; Benoist, A.; Teulon, H.; Daude, J.

2012-01-01

This collective publication aims at being a course for students in engineering of energetic systems, i.e. at learning how to decide to accept or discard a project, to select the most efficient system, to select the optimal system, to select the optimal combination of systems, and to classify independent systems. Thus, it presents methods to analyse system life cycle from an energetic, economic and environmental point of view, describes how to develop an approach to the eco-design of an energy consuming product, how to understand the importance of hypotheses behind abundant and often contradicting publicised results, and to be able to criticise or to put in perspective one's own analysis. The first chapters thus recall some aspects of economic calculation, introduce the assessment of investment and exploitation costs of energetic systems, describe how to assess and internalise environmental costs, present the territorial carbon assessment, discuss the use of the life cycle assessment, and address the issue of environmental management at a product scale. The second part proposes various case studies: an optimal fleet of thermal production of electric power, the eco-design of a refrigerator, the economic and environmental assessment of wind farms

Nuclear energetics all over the world

International Nuclear Information System (INIS)

Wojcik, T.

2000-01-01

The actual state and tendencies of nuclear power further development for different world regions have been presented and discussed. The problem of safety of energetic nuclear reactors, radioactive waste management and related problems have been discussed in respect of regulations in different countries. The economical aspects of nuclear energetics in comparison with different fossil fuel power plants exploitation costs has been presented as well. The official state of international organizations (IAEA, WANO, HASA etc.) have been also shown in respect to subject presented

Energetic certification in Europe

International Nuclear Information System (INIS)

1998-01-01

At community level the problem of energy quality control in a building was introduced by EEC recommendation n. 93/76 in 1993. In this item are reported some notes on energetic certification in European countries [it

Energetic Particles Dynamics in Mercury's Magnetosphere

Science.gov (United States)

Walsh, Brian M.; Ryou, A.S.; Sibeck, D. G.; Alexeev, I. I.

2013-01-01

We investigate the drift paths of energetic particles in Mercury's magnetosphere by tracing their motion through a model magnetic field. Test particle simulations solving the full Lorentz force show a quasi-trapped energetic particle population that gradient and curvature drift around the planet via "Shabansky" orbits, passing though high latitudes in the compressed dayside by equatorial latitudes on the nightside. Due to their large gyroradii, energetic H+ and Na+ ions will typically collide with the planet or the magnetopause and will not be able to complete a full drift orbit. These simulations provide direct comparison for recent spacecraft measurements from MESSENGER. Mercury's offset dipole results in an asymmetric loss cone and therefore an asymmetry in particle precipitation with more particles precipitating in the southern hemisphere. Since the planet lacks an atmosphere, precipitating particles will collide directly with the surface of the planet. The incident charged particles can kick up neutrals from the surface and have implications for the formation of the exosphere and weathering of the surface

Energetic Materials Effects on Essential Soil Processes: Decomposition of Orchard Grass (Dactylis glomerata) Litter in Soil Contaminated with Energetic Materials

Science.gov (United States)

2014-02-01

availabilities of their respective food sources (bacteria and fungi ), were also unaffected-or-increasing in soil with CL-20 treatments. This is...ENERGETIC MATERIALS EFFECTS ON ESSENTIAL SOIL PROCESSES: DECOMPOSITION OF ORCHARD...GRASS (DACTYLIS GLOMERATA) LITTER IN SOIL CONTAMINATED WITH ENERGETIC MATERIALS ECBC-TR-1199 Roman G. Kuperman Ronald T. Checkai Michael Simini

Computational studies on energetic properties of nitrogen-rich ...

Indian Academy of Sciences (India)

Computational studies on energetic properties of nitrogen-rich energetic materials with ditetrazoles. LI XIAO-HONGa,b,∗ and ZHANG RUI-ZHOUa. aCollege of Physics and Engineering, Henan University of Science and Technology, Luoyang 471 003, China. bLuoyang Key Laboratory of Photoelectric Functional Materials, ...

The Energetics of Economics (Money as access to Energy)

OpenAIRE

Ternyik, Stephen I.

2013-01-01

Money is being portrayed as temporal access to energy and a new methodical approach to the energetics of the human economy is introduced.The economic evolution of world system energetics is put into the historical focus of all global monetary civilization, reaching back to Sumerian city states.This long wave energetics of human economic action clearly points to the biophysical boundaries of the globalized monetary production economy which is also based on natural law.The future perspective of...

Ventricular arrhythmia burst is an independent indicator of larger infarct size even in optimal reperfusion in STEMI

NARCIS (Netherlands)

van der Weg, Kirian; Majidi, Mohamed; Haeck, Joost D. E.; Tijssen, Jan G. P.; Green, Cynthia L.; Koch, Karel T.; Kuijt, Wichert J.; Krucoff, Mitchell W.; Gorgels, Anton P. M.; de Winter, Robbert J.

2016-01-01

We hypothesized that ventricular arrhythmia (VA) bursts during reperfusion phase are a marker of larger infarct size despite optimal epicardial and microvascular perfusion. 126 STEMI patients were studied with 24h continuous, 12-lead Holter monitoring. Myocardial blush grade (MBG) was determined and

Integrative computational models of cardiac arrhythmias -- simulating the structurally realistic heart

Science.gov (United States)

Trayanova, Natalia A; Tice, Brock M

2009-01-01

Simulation of cardiac electrical function, and specifically, simulation aimed at understanding the mechanisms of cardiac rhythm disorders, represents an example of a successful integrative multiscale modeling approach, uncovering emergent behavior at the successive scales in the hierarchy of structural complexity. The goal of this article is to present a review of the integrative multiscale models of realistic ventricular structure used in the quest to understand and treat ventricular arrhythmias. It concludes with the new advances in image-based modeling of the heart and the promise it holds for the development of individualized models of ventricular function in health and disease. PMID:20628585

In Vitro Cardiomyogenic Potential of Human Amniotic Fluid Stem Cells

OpenAIRE

Guan, Xuan; Delo, Dawn M.; Atala, Anthony; Soker, Shay

2011-01-01

Stem cell therapy for damaged cardiac tissue is currently limited by a number of factors, including the inability to obtain sufficient cell numbers, the potential tumorigenicity of certain types of stem cells, and the possible link between stem cell therapy and the development of malignant arrhythmias. In this study, we investigated whether human amniotic fluid-derived stem (hAFS) cells could be a potential source of cells for cardiac cell therapy by testing the in vitro differentiation capab...

Inhibition of N-type Ca2+ channels ameliorates an imbalance in cardiac autonomic nerve activity and prevents lethal arrhythmias in mice with heart failure.

Science.gov (United States)

Yamada, Yuko; Kinoshita, Hideyuki; Kuwahara, Koichiro; Nakagawa, Yasuaki; Kuwabara, Yoshihiro; Minami, Takeya; Yamada, Chinatsu; Shibata, Junko; Nakao, Kazuhiro; Cho, Kosai; Arai, Yuji; Yasuno, Shinji; Nishikimi, Toshio; Ueshima, Kenji; Kamakura, Shiro; Nishida, Motohiro; Kiyonaka, Shigeki; Mori, Yasuo; Kimura, Takeshi; Kangawa, Kenji; Nakao, Kazuwa

2014-10-01

Dysregulation of autonomic nervous system activity can trigger ventricular arrhythmias and sudden death in patients with heart failure. N-type Ca(2+) channels (NCCs) play an important role in sympathetic nervous system activation by regulating the calcium entry that triggers release of neurotransmitters from peripheral sympathetic nerve terminals. We have investigated the ability of NCC blockade to prevent lethal arrhythmias associated with heart failure. We compared the effects of cilnidipine, a dual N- and L-type Ca(2+) channel blocker, with those of nitrendipine, a selective L-type Ca(2+) channel blocker, in transgenic mice expressing a cardiac-specific, dominant-negative form of neuron-restrictive silencer factor (dnNRSF-Tg). In this mouse model of dilated cardiomyopathy leading to sudden arrhythmic death, cardiac structure and function did not significantly differ among the control, cilnidipine, and nitrendipine groups. However, cilnidipine dramatically reduced arrhythmias in dnNRSF-Tg mice, significantly improving their survival rate and correcting the imbalance between cardiac sympathetic and parasympathetic nervous system activity. A β-blocker, bisoprolol, showed similar effects in these mice. Genetic titration of NCCs, achieved by crossing dnNRSF-Tg mice with mice lacking CACNA1B, which encodes the α1 subunit of NCCs, improved the survival rate. With restoration of cardiac autonomic balance, dnNRSF-Tg;CACNA1B(+/-) mice showed fewer malignant arrhythmias than dnNRSF-Tg;CACNA1B(+/+) mice. Both pharmacological blockade of NCCs and their genetic titration improved cardiac autonomic balance and prevented lethal arrhythmias in a mouse model of dilated cardiomyopathy and sudden arrhythmic death. Our findings suggest that NCC blockade is a potentially useful approach to preventing sudden death in patients with heart failure. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

Interaction in the large energetic companies in the Republic of Macedonia

International Nuclear Information System (INIS)

Janevski, Risto

1999-01-01

After disintegration of former power energetic system of Yugoslavia 1991, the Republic of Macedonia has faced enormous problems in the energetic field. It was necessary to realize all options in order to secure enough electric power for normal economic capacities function. In that course a direct involvement of five large companies, which represent very significant energetic subjects, will largely determine the future energetic conditions and circumstances in our country. These are the following companies: P.E. Electric Power Company Of Macedonia; OKTA Crude Oil Refinery; Heat Power Company; HEK Jugohrom; Fenimak. The paper presents the electric power consumption of these macro energetic companies during the period 1991-1998

Observations of Energetic Particle Escape at the Magnetopause: Early Results from the MMS Energetic Ion Spectrometer (EIS)

Science.gov (United States)

Cohen, I. J.; Mauk, B. H.; Anderson, B. J.; Westlake, J. H.; Sibeck, David Gary; Giles, Barbara L.; Pollock, C. J.; Turner, D. L.; Fennell, J. F.; Blake, J. B.;

Novel Calmodulin (CALM2) Mutations Associated with Congenital Arrhythmia Susceptibility

Science.gov (United States)

Makita, Naomasa; Yagihara, Nobue; Crotti, Lia; Johnson, Christopher N.; Beckmann, Britt-Maria; Roh, Michelle S.; Shigemizu, Daichi; Lichtner, Peter; Ishikawa, Taisuke; Aiba, Takeshi; Homfray, Tessa; Behr, Elijah R.; Klug, Didier; Denjoy, Isabelle; Mastantuono, Elisa; Theisen, Daniel; Tsunoda, Tatsuhiko; Satake, Wataru; Toda, Tatsushi; Nakagawa, Hidewaki; Tsuji, Yukiomi; Tsuchiya, Takeshi; Yamamoto, Hirokazu; Miyamoto, Yoshihiro; Endo, Naoto; Kimura, Akinori; Ozaki, Kouichi; Motomura, Hideki; Suda, Kenji; Tanaka, Toshihiro; Schwartz, Peter J.; Meitinger, Thomas; Kääb, Stefan; Guicheney, Pascale; Shimizu, Wataru; Bhuiyan, Zahurul A.; Watanabe, Hiroshi; Chazin, Walter J.; George, Alfred L.

2014-01-01

Background Genetic predisposition to life-threatening cardiac arrhythmias such as in congenital long-QT syndrome (LQTS) and catecholaminergic polymorphic ventricular tachycardia (CPVT) represent treatable causes of sudden cardiac death in young adults and children. Recently, mutations in calmodulin (CALM1, CALM2) have been associated with severe forms of LQTS and CPVT, with life-threatening arrhythmias occurring very early in life. Additional mutation-positive cases are needed to discern genotype-phenotype correlations associated with calmodulin mutations. Methods and Results We employed conventional and next-generation sequencing approaches including exome analysis in genotype-negative LQTS probands. We identified five novel de novo missense mutations in CALM2 in three subjects with LQTS (p.N98S, p.N98I, p.D134H) and two subjects with clinical features of both LQTS and CPVT (p.D132E, p.Q136P). Age of onset of major symptoms (syncope or cardiac arrest) ranged from 1–9 years. Three of five probands had cardiac arrest and one of these subjects did not survive. Although all probands had LQTS, two subjects also exhibited electrocardiographic features consistent with CPVT. The clinical severity among subjects in this series was generally less than that originally reported for CALM1 and CALM2 associated with recurrent cardiac arrest during infancy. Four of five probands responded to β-blocker therapy whereas one subject with mutation p.Q136P died suddenly during exertion despite this treatment. Mutations affect conserved residues located within calcium binding loops III (p.N98S, p.N98I) or IV (p.D132E, p.D134H, p.Q136P) and caused reduced calcium binding affinity. Conclusions CALM2 mutations can be associated with LQTS and with overlapping features of LQTS and CPVT. PMID:24917665

Quantifying the energetics of cooperativity in a ternary protein complex

DEFF Research Database (Denmark)

Andersen, Peter S; Schuck, Peter; Sundberg, Eric J

2002-01-01

and mathematical modeling to describe the energetics of cooperativity in a trimolecular protein complex. As a model system for quantifying cooperativity, we studied the ternary complex formed by the simultaneous interaction of a superantigen with major histocompatibility complex and T cell receptor, for which...... a structural model is available. This system exhibits positive and negative cooperativity, as well as augmentation of the temperature dependence of binding kinetics upon the cooperative interaction of individual protein components in the complex. Our experimental and theoretical analysis may be applicable...... to other systems involving cooperativity....

Quinquennial National Program (1990-1994) for the Energetic Modernization

International Nuclear Information System (INIS)

1990-01-01

The Mexican Energetics Sector currently has the eighth possition regarding reserves of hydrocarbons and the sixth regarding oil production, the installed capacity in electricity matters is among the first 20 of the world. The Program established first, a general balance of the situation in which the energetics sector lays today. It also points out the strategic role that this sector holds, as well an on the solutions to the problems faced. This Program establishes the objectives pursued by the energetics sector and that are as follows: to guarantee enough supply of energetics, to strenghten the link between the energetics sector and economy, society and environmental protection, to consolidate an energetics sector that is more current and better integrated. This Program presents the proposal to tend to five priorities: productivity, saving and effective use of energy, financing of the development and expansion of the offer, to diversify sources, as well as an efficient participation in international markets. In the chapter the effort regarding supply and demand of energy, it is evident that the effort made to expand the offer must be great, facing the total demand of energy demonstrated by the figures. For 1994 this demmand is of 31 - 36 % greater to that observed in 1988. Lastly, two statistic documents are enclosed, one historic, with general pointers of the sector, and another with the basic variables for national energy balance

Cardiac Arrhythmias in Children with Sickle Cell Anaemia | Bode ...

African Journals Online (AJOL)

Background : Sickle cell anaemia (SCA) is an important cause of morbidity and mortality in tropical Africa. Recurrent episodes of vaso-occlusive crisis often lead to organ ischaemia and/or infarction. Arrythmias are common and reliable manifestations of myocardial ischaemia and often follow infarction. The prevalence and ...

The energetic significance of cooking.

Science.gov (United States)

Carmody, Rachel N; Wrangham, Richard W

2009-10-01

While cooking has long been argued to improve the diet, the nature of the improvement has not been well defined. As a result, the evolutionary significance of cooking has variously been proposed as being substantial or relatively trivial. In this paper, we evaluate the hypothesis that an important and consistent effect of cooking food is a rise in its net energy value. The pathways by which cooking influences net energy value differ for starch, protein, and lipid, and we therefore consider plant and animal foods separately. Evidence of compromised physiological performance among individuals on raw diets supports the hypothesis that cooked diets tend to provide energy. Mechanisms contributing to energy being gained from cooking include increased digestibility of starch and protein, reduced costs of digestion for cooked versus raw meat, and reduced energetic costs of detoxification and defence against pathogens. If cooking consistently improves the energetic value of foods through such mechanisms, its evolutionary impact depends partly on the relative energetic benefits of non-thermal processing methods used prior to cooking. We suggest that if non-thermal processing methods such as pounding were used by Lower Palaeolithic Homo, they likely provided an important increase in energy gain over unprocessed raw diets. However, cooking has critical effects not easily achievable by non-thermal processing, including the relatively complete gelatinisation of starch, efficient denaturing of proteins, and killing of food borne pathogens. This means that however sophisticated the non-thermal processing methods were, cooking would have conferred incremental energetic benefits. While much remains to be discovered, we conclude that the adoption of cooking would have led to an important rise in energy availability. For this reason, we predict that cooking had substantial evolutionary significance.

Sawteeth stabilization by energetic trapped ions

International Nuclear Information System (INIS)

Samain, A.; Edery, D.; Garbet, X.; Roubin, J.P.

1991-01-01

The analysis of a possible stabilization of sawteeth by a population of energetic ions is performed by using the Lagrangian of the electromagnetic perturbation. It is shown that the trapped component of such a population has a small influence compared to that of the passing component. The stabilization threshold is calculated assuming a non linear regime in the q=1 resonant layer. The energetic population must create a stable tearing structure if the average curvature effect on thermal particles in the layer is small. However, this effect decreases the actual threshold

Very energetic photons at HERA

International Nuclear Information System (INIS)

Bawa, A.C.; Krawczyk, M.

1991-01-01

We show that every energetic photons in the backward direction can be produced in deep inelastic Compton scattering at HERA. Assuming a fixed energy of 9 GeV for the initial photons and 820 GeV for the protons a high rate is found for the production of final photons with a transverse momentum equal to 5 GeV/c and energy between 40 GeV and 300 GeV. These energetic photons arise mainly from the scattering of the soft gluonic constituents of the initial photon with quarks from the proton. They are produced in the backward direction in coincidence with a photon beam jet of energy ∝ 9 GeV in the forward direction. (orig.)

Study of energetic dependence of LiF TLDs for photons

International Nuclear Information System (INIS)

Cavalieri, Tassio A.; Antunes, Paula C.G.; Paiva, Fabio; Branco, Isabela S.; Sena, Michelle K.S.; Siqueira, Paulo T.D.; Yoriyaz, Helio

2015-01-01

The LiF TLDs are widely used for photon dosimetry. However, in the most case the energetic dependence of these TLDs are not taken into account. This work is a preliminary study of energetic photon dependence in LiF TLD (TLD 700, enriched with 7 Li). For this study it was utilized a methodology already used in others works that seek understand the dependence energetic of TLD. It was utilized three different X-ray spectrum and a 137 Cs source; Beyond the calculus utilized in previous works, it was built the calibration curve for each spectrum to see the difference in dosimetry that the energetic dependence could cause. (author)

Study of energetic dependence of LiF TLDs for photons

Energy Technology Data Exchange (ETDEWEB)

Cavalieri, Tassio A.; Antunes, Paula C.G.; Paiva, Fabio; Branco, Isabela S.; Sena, Michelle K.S.; Siqueira, Paulo T.D.; Yoriyaz, Helio, E-mail: tcavalieri@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2015-07-01

The LiF TLDs are widely used for photon dosimetry. However, in the most case the energetic dependence of these TLDs are not taken into account. This work is a preliminary study of energetic photon dependence in LiF TLD (TLD 700, enriched with {sup 7}Li). For this study it was utilized a methodology already used in others works that seek understand the dependence energetic of TLD. It was utilized three different X-ray spectrum and a {sup 137}Cs source; Beyond the calculus utilized in previous works, it was built the calibration curve for each spectrum to see the difference in dosimetry that the energetic dependence could cause. (author)

Energetics Manufacturing Technology Center (EMTC)

Data.gov (United States)

Federal Laboratory Consortium — The Energetics Manufacturing Technology Center (EMTC), established in 1994 by the Office of Naval Research (ONR) Manufacturing Technology (ManTech) Program, is Navy...

Chaos for cardiac arrhythmias through a one-dimensional modulation equation for alternans

Science.gov (United States)

Dai, Shu; Schaeffer, David G.

2010-01-01

Instabilities in cardiac dynamics have been widely investigated in recent years. One facet of this work has studied chaotic behavior, especially possible correlations with fatal arrhythmias. Previously chaotic behavior was observed in various models, specifically in the breakup of spiral and scroll waves. In this paper we study cardiac dynamics and find spatiotemporal chaotic behavior through the Echebarria–Karma modulation equation for alternans in one dimension. Although extreme parameter values are required to produce chaos in this model, it seems significant mathematically that chaos may occur by a different mechanism from previous observations. PMID:20590327

Sanitation of cultural monuments - Energy conervation. Energetic improvement of buildings listed as monuments; Kulturdenkmale sanieren - Energie sparen. Energetische Verbesserung denkmalgeschuetzter Gebaeude

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-08-15

The contribution under consideration reports on an energetic improvement of buildings listed as monuments. Substantial aspects are designated which absolutely have to be considered in the energetic sanitation. Depending upon plant (solar thermal power or photovoltaics), dimensions and other design (cell type, colour, reflection) solutions can be found which only insignificantly impair the appearance of the architectural monument. Partners for buildings listed as monument are monument protection authorities. The contribution under consideration also presents an overview of public funding programs.

Adrenal and extra-adrenal pheochromocytomas presenting as life-threatening ventricular arrhythmias: Report of three cases

Directory of Open Access Journals (Sweden)

Sai Satish Oruganti

2016-05-01

Full Text Available Pheochromocytoma patients can rarely have prolonged QT interval in the ECG. We report three cases of pheochromocytoma in females presenting with ventricular arrhythmia; two had torsades de pointes and a third patient had frequent VPCs and nonsustained ventricular tachycardia. All the patients were treated with surgical removal of the tumor with complete relief of symptoms and normalization of QT interval.

The influence of motor activity on the development of cardiac arrhythmias during experimental emotional stress

Science.gov (United States)

Ulyaninskiy, L. S.; Urmancheyeva, T. G.; Stepanyan, Y. P.; Fufacheva, A. A.; Gritsak, A. V.; Kuznetsova, B. A.; Kvitka, A. A.

1982-01-01

Experimental emotional stress which can produce various disorders of cardiac rhythm: sinus tachycardia, atrial fibrillation, ventricular, extrasystoles and paroxysmal ventricular tachysystoles was studied. In these conditions the adrenalin content in the blood and myocardium is increased 3 to 4 times. It is found that moderate motor activity leads to a relative decrease of adrenalin in the myocardium and arrest of cardiac arrhythmias.

Forecast of nuclear energetics

Energy Technology Data Exchange (ETDEWEB)

Sikora, W

1976-01-01

The forecast concerning the development of nuclear energetics is presented. Some information on economics of nuclear power plants is given. The nuclear fuel reserves are estimated on the background of power resources of the world. The safety and environment protection problems are mentioned.

Energetic particle pressure in intense ESP events

Science.gov (United States)

Lario, D.; Decker, R. B.; Roelof, E. C.; Viñas, A.-F.

2015-09-01

We study three intense energetic storm particle (ESP) events in which the energetic particle pressure PEP exceeded both the pressure of the background thermal plasma Pth and the pressure of the magnetic field PB. The region upstream of the interplanetary shocks associated with these events was characterized by a depression of the magnetic field strength coincident with the increase of the energetic particle intensities and, when plasma measurements were available, a depleted solar wind density. The general feature of cosmic-ray mediated shocks such as the deceleration of the upstream background medium into which the shock propagates is generally observed. However, for those shocks where plasma parameters are available, pressure balance is not maintained either upstream of or across the shock, which may result from the fact that PEP is not included in the calculation of the shock parameters.

AV-block and conduction slowing prevail over TdP arrhythmias in the methoxamine-sensitized pro-arrhythmic rabbit model

NARCIS (Netherlands)

Varkevisser, Rosanne; Vos, Marc A; Beekman, Jet; Tieland, Ralph G; Van Der Heyden, Marcel A

INTRODUCTION: The methoxamine-sensitized rabbit model is widely used to screen drugs for proarrhythmic properties, especially repolarization-dependent TdP arrhythmias. With the change of anesthesia and/or sensitizing agent, conduction disturbances have been reported as well. Therefore, we compared

Atypical dengue meningitis in Makkah, Saudi Arabia with slow resolving, prominent migraine like headache, phobia, and arrhythmia

Directory of Open Access Journals (Sweden)

Kalakatawi H Mamdouh

2013-01-01

Full Text Available Although dengue meningitis is a rare presentation of dengue infection, our aim is to focus on atypical presentation of dengue meningitis that may appear in dengue endemic area like the Makkah region. We report two cases of clinical meningitis with positive dengue virus (DENV IgM in cerebrospinal fluid, followed for minimal 3 months for their prominent attacks of migraine like headache, phobia, and arrhythmia. With special consideration to attack time, type, severity, and respond to classical therapy, using regular ECG monitoring, visual analog pain score and neuropsychological assessments were done. Both cases showed resistant migraine like headaches to classic anti-migraine therapy except for strong NSAID and narcotics with tendency to have severe to extreme severe daily migraine like headache on early to late afternoon time, associated with non-fatal arrhythmias and extreme death phobia, that resolve slowly in a minimal 3 month period. In conclusion, dengue meningitis in the endemic area may present atypically.

Nuclear energy I, Non-energetic applications

International Nuclear Information System (INIS)

Lartigue G, J.; Navarrete T, M.; Cabrera M, L.; Arandia, P.A.; Arriola S, H.

1986-01-01

The nuclear energy is defined as the energy produced or absorbed in the nuclear reactions, therefore, these are divided in endothermic and exothermic. The exothermic nuclear reactions present more interest from the point of view of its applications and they can show in four main forms: radioactivity (from 0 to 4 MeV/reaction; light nucleus fusion ( ∼ 20 MeV/reaction), heavy nucleus fusion (∼ 200 MeV/reaction) and nucleons annihilation ( ∼ 2000 MeV/reaction). Nowadays only the fission has reached the stage of profitable energetic application, finding the other three forms in research and development. The non-energetic applications of the nuclear energy are characterized by they do not require of prior conversion to another form of energy and they are made through the use of radioisotopes as well as through the use of endothermic reaction caused in particle accelerators. In this work are presented some of the non-energetic applications with its theoretical and experimental basis as well as its benefits of each one. (Author)

From Incidental, Mechanically-Induced Arrhythmias to Reflex-Defined Arrhythmogenicity: On The Track of The Ternary Reflex System Resemblance to The "Infancy" of New Era or Rediscovery.

Science.gov (United States)

Stirbys, Petras

2016-01-01

The underlying pathophysiology of supraventricular and ventricular arrhythmias remains a matter of intense investigation. Though evolving, the contemporary explanations do not encompass all aspects of arrhythmogenicity. An improved understanding of arrhythmia substrate is needed to augment therapeutic capabilities. Our observation and literature sources demonstrate relatively high incidence of transitory arrhythmias which are non-intentionally generated by the endocardial lead/catheter manipulation. These findings are interesting and potentially may crystallize the reflex-dependent proarrhythmic cardiac activity. Herein we suggest the "reflexogenic arrhythmogenicity" concept extending an overall spectrum of known hypotheses. Cardiovascular reflex action can be categorized into three-tiered levels - intra-cellular, inter-cellular and inter-organic. The first two levels of the triplicate system reside within the cardiac anatomical landmarks (in fact intramurally, intra-organically), however the third one implicates central (cerebral) activity which boomerangs back via centripetal and centrifugal connections. These levels likely compose synoptic ternary reflex set system which may be validated in future studies. To hypothesize, coordinated mutual reciprocity of reflex activity results in stabilization of heart rhythm in robust heart. Any stressful cardiac event may lead to the shift of the rhythm toward unfavorable clinical entity probably via the loss of the influence of dominant reflex. Overall, an interaction and likely intrinsic inter-tiered competition along with possible interplay between physiological and pathological reflexes may be treated as contributing factors for the inception and maintaining of arrhythmias and cardiac performance as well. These assumptions await further documentation. If such a tenet were recognized, the changes in the clinical approach to arrhythmia management might be anticipated, preferably by selective reflex suppression or

Salade malade: malignant ventricular arrhythmias due to an accidental intoxication with Aconitum napellus.

Science.gov (United States)

Weijters, B J; Verbunt, R J A M; Hoogsteen, J; Visser, R F

2008-01-01

Intoxication with Aconitum napellus is rare in our regions. Aconite alkaloids can cause ventricular arrhythmia by a prolonged activation of sodium channels. Because the margin of safety is low between the analgesic and toxic dose, intoxication is not rare when Aconite is used in herbal medicine. We present a case in which a 39-year-old male was accidentally intoxicated with Aconite. Even though no antidote or adequate therapy is available he was successfully resuscitated. (Neth Heart J 2008;16:96-9.).

Energetic assessment of soybean biodiesel obtainment in West ...

African Journals Online (AJOL)

SAM

2014-07-16

Jul 16, 2014 ... Energetic outputs added up to 3,003.75 MJ and energy balance was 57,132.54 MJ. ... biodiesel, the study was divided into three stages: soybean farming, ... considering energetic consumptions with labor, seeds, diesel oil, ... model MF 283(4X2 TDA), power 63.2 kW (86 cv) in the engine, board weight.

Resistive interchange mode destabilized by helically trapped energetic ions and its effects on energetic ions and bulk plasmas

International Nuclear Information System (INIS)

Du, X.D.; Toi, K.; Osakabe, M.

2014-10-01

A resistive interchange mode with bursting behavior and rapid frequency chirping in the range less than 10 kHz is observed for the first time in the magnetic hill region of net current-free, low beta LHD (Large Helical Device) plasmas during high power injection of perpendicular neutral beams. The mode resonates with the precession motion of helically trapped energetic beam ions, following the resonant condition. The radial mode structure is found to be very similar to that of usual pressure-driven interchange mode, of which radial displacement eigenfunction has an even function around the rational surface. This beam driven mode is excited when the beta value of helically trapped energetic ions exceed a certain threshold. The radial transport of helically trapped energetic ions induced by the mode transiently generates significant radial electric field near the plasma peripheral region. Thus generated radial electric field clearly suppresses micro turbulence and improves bulk plasma confinement, suggesting strong flow shear generation. (author)

Particles Alter Diesel Exhaust Gases-Induced Hypotension, Cardiac Arrhythmia,Conduction Disturbance, and Autonomic Imbalance in Heart Failure-Prone Rats

Science.gov (United States)

Epidemiologic studies indicate that acute exposures to vehicular traffic and particulate matter (PM) air pollution are key causes of fatal cardiac arrhythmia, especially in those with preexisting cardiovascular disease. Researchers point to electrophysiologic dysfunction and auto...

Streaming reversal of energetic particles in the magnetotail during a substorm

Science.gov (United States)

Lui, A. T. Y.; Williams, D. J.; Eastman, T. E.; Frank, L. A.; Akasofu, S.-I.

1984-01-01

A case of reversal in the streaming anisotropy of energetic ions and in the plasma flow observed from the IMP 8 spacecraft during a substorm on February 8, 1978 is studied in detail using measurements of energetic particles, plasma, and magnetic field. Four new features emerge when high time resolution data are examined in detail. The times of streaming reversal of energetic particles in different energy ranges do not coincide with the time of plasma flow reversal. Qualitatively different velocity distributions are observed in earthward and tailward plasma flows during the observed flow reversal intervals. Strong tailward streaming of energetic particles can be detected during northward magnetic field environments and, conversely, earthward streaming in southward field environments. During the period of tailward streaming of energetic particles, earthward streaming fluxes are occasionally detected.

An Automated Platform for Assessment of Congenital and Drug-Induced Arrhythmia with hiPSC-Derived Cardiomyocytes

Directory of Open Access Journals (Sweden)

Wesley L. McKeithan

2017-10-01

Full Text Available The ability to produce unlimited numbers of human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs harboring disease and patient-specific gene variants creates a new paradigm for modeling congenital heart diseases (CHDs and predicting proarrhythmic liabilities of drug candidates. However, a major roadblock to implementing hiPSC-CM technology in drug discovery is that conventional methods for monitoring action potential (AP kinetics and arrhythmia phenotypes in vitro have been too costly or technically challenging to execute in high throughput. Herein, we describe the first large-scale, fully automated and statistically robust analysis of AP kinetics and drug-induced proarrhythmia in hiPSC-CMs. The platform combines the optical recording of a small molecule fluorescent voltage sensing probe (VoltageFluor2.1.Cl, an automated high throughput microscope and automated image analysis to rapidly generate physiological measurements of cardiomyocytes (CMs. The technique can be readily adapted on any high content imager to study hiPSC-CM physiology and predict the proarrhythmic effects of drug candidates.

Energetic Ion Loss Diagnostic for the Wendelstein 7-AS Stellarator

International Nuclear Information System (INIS)

Darrow, D. S.; Werner, A.; Weller, A.

2000-01-01

A diagnostic to measure the loss of energetic ions from the Wendelstein 7-AS (W7-AS) stellarator has been built. It is capable of measuring losses of both neutral beam ions and energetic ions arising from ion cyclotron resonant heating. The probe can measure losses of both clockwise and counterclockwise-going energetic ions simultaneously, and accepts a wide range of pitch angles in both directions. Initial measurements by the diagnostic are reported

Energetics of hydrogen bonding in proteins: a model compound study.

OpenAIRE

Habermann, S. M.; Murphy, K. P.

1996-01-01

Differences in the energetics of amide-amide and amide-hydroxyl hydrogen bonds in proteins have been explored from the effect of hydroxyl groups on the structure and dissolution energetics of a series of crystalline cyclic dipeptides. The calorimetrically determined energetics are interpreted in light of the crystal structures of the studied compounds. Our results indicate that the amide-amide and amide-hydroxyl hydrogen bonds both provide considerable enthalpic stability, but that the amide-...

Cardiac arrhythmia with premature ventricular contractures induced by interferon beta in a patient with multiple sclerosis

Directory of Open Access Journals (Sweden)

Igor Sobol

2015-03-01

Full Text Available Multiple sclerosis (MS is an immune-mediated inflammatory and neurodegenerative disease of the central nervous system. Interferon (IFN beta is an active ingredient of five out of twelve disease modifying treatments approved for MS. We report a case of IFN-beta-induced cardiac arrhythmia with premature ventricular contractures in a patient recently diagnosed with MS.

Theoretical Studies of Alfven Waves and Energetic Particle Physics in Fusion Plasmas

Energy Technology Data Exchange (ETDEWEB)

Chen, Liu [Univ. of California, Irvine, CA (United States)

2017-12-20

This report summarizes major theoretical findings in the linear as well as nonlinear physics of Alfvén waves and energetic particles in magnetically confined fusion plasmas. On the linear physics, a variational formulation, based on the separation of singular and regular spatial scales, for drift-Alfvén instabilities excited by energetic particles is established. This variational formulation is then applied to derive the general fishbone-like dispersion relations corresponding to the various Alfvén eigenmodes and energetic-particle modes. It is further employed to explore in depth the low-frequency Alfvén eigenmodes and demonstrate the non-perturbative nature of the energetic particles. On the nonlinear physics, new novel findings are obtained on both the nonlinear wave-wave interactions and nonlinear wave-energetic particle interactions. It is demonstrated that both the energetic particles and the fine radial mode structures could qualitatively affect the nonlinear evolution of Alfvén eigenmodes. Meanwhile, a theoretical approach based on the Dyson equation is developed to treat self-consistently the nonlinear interactions between Alfvén waves and energetic particles, and is then applied to explain simulation results of energetic-particle modes. Relevant list of journal publications on the above findings is also included.

THE USE OF OMEGA-3 FATTY ACIDS FOR THE TREATMENT OF PATIENTS WITH CARDIAC ARRHYTHMIAS

Directory of Open Access Journals (Sweden)

A. O. Malygin

2015-09-01

Full Text Available Antiarrhythmic effect of omega-3 polyunsaturated fatty acids (ω-3 PUFA, eicosapentaenoic and docosahexaenoic acids in patients with recurrent atrial fibrillation and ventricular arrhythmias had been proven. The positive effect of the ω-3 PUFA on the risk of sudden arrhythmic death and overall mortality in the patients after myocardial infarction and patients with chronic heart failure had been also proven.

Energetic and metabolic transient response of Saccharomyces cerevisiae to benzoic acid.

Science.gov (United States)

Kresnowati, M T A P; van Winden, W A; van Gulik, W M; Heijnen, J J

2008-11-01

Saccharomyces cerevisiae is known to be able to adapt to the presence of the commonly used food preservative benzoic acid with a large energy expenditure. Some mechanisms for the adaptation process have been suggested, but its quantitative energetic and metabolic aspects have rarely been discussed. This study discusses use of the stimulus response approach to quantitatively study the energetic and metabolic aspects of the transient adaptation of S. cerevisiae to a shift in benzoic acid concentration, from 0 to 0.8 mM. The information obtained also serves as the basis for further utilization of benzoic acid as a tool for targeted perturbation of the energy system, which is important in studying the kinetics and regulation of central carbon metabolism in S. cerevisiae. Using this experimental set-up, we found significant fast-transient (< 3000 s) increases in O(2) consumption and CO(2) production rates, of approximately 50%, which reflect a high energy requirement for the adaptation process. We also found that with a longer exposure time to benzoic acid, S. cerevisiae decreases the cell membrane permeability for this weak acid by a factor of 10 and decreases the cell size to approximately 80% of the initial value. The intracellular metabolite profile in the new steady-state indicates increases in the glycolytic and tricarboxylic acid cycle fluxes, which are in agreement with the observed increases in specific glucose and O(2) uptake rates.

Energetic charged particles above thunderclouds

International Nuclear Information System (INIS)

Fullekrug, Martin; Diver, Declan; Pincon, Jean-Louis; Renard, Jean-Baptiste; Phelps, Alan D.R.; Bourdon, Anne; Helling, Christiane; Blanc, Elisabeth; Honary, Farideh; Kosch, Mike; Harrison, Giles; Sauvaud, Jean-Andre; Lester, Mark; Rycroft, Michael; Kosch, Mike; Horne, Richard B.; Soula, Serge; Gaffet, Stephane

2013-01-01

The French government has committed to launch the satellite TARANIS to study transient coupling processes between the Earth's atmosphere and near-Earth space. The prime objective of TARANIS is to detect energetic charged particles and hard radiation emanating from thunderclouds. The British Nobel prize winner C. T. R. Wilson predicted lightning discharges from the top of thunderclouds into space almost a century ago. However, new experiments have only recently confirmed energetic discharge processes which transfer energy from the top of thunderclouds into the upper atmosphere and near-Earth space; they are now denoted as transient luminous events, terrestrial gamma-ray flashes and relativistic electron beams. This meeting report builds on the current state of scientific knowledge on the physics of plasmas in the laboratory and naturally occurring plasmas in the Earth's atmosphere to propose areas of future research. The report specifically reflects presentations delivered by the members of a novel Franco-British collaboration during a meeting at the French Embassy in London held in November 2011. The scientific subjects of the report tackle ionization processes leading to electrical discharge processes, observations of transient luminous events, electromagnetic emissions, energetic charged particles and their impact on the Earth's atmosphere. The importance of future research in this area for science and society, and towards spacecraft protection, is emphasized. (authors)

Differential Susceptibility and the Early Development of Aggression: Interactive Effects of Respiratory Sinus Arrhythmia and Environmental Quality

Science.gov (United States)

Eisenberg, Nancy; Sulik, Michael J.; Spinrad, Tracy L.; Edwards, Alison; Eggum, Natalie D.; Liew, Jeffrey; Sallquist, Julie; Popp, Tierney K.; Smith, Cynthia L.; Hart, Daniel

2012-01-01

The purpose of the current study was to predict the development of aggressive behavior from young children's respiratory sinus arrhythmia (RSA) and environmental quality. In a longitudinal sample of 213 children, baseline RSA, RSA suppression in response to a film of crying babies, and a composite measure of environmental quality (incorporating…

A comparison of heart function and arrhythmia in clinically asymptomatic patients with beta thalassemia intermedia and beta thalassemia major.

Science.gov (United States)

Amoozgar, Hamid; Zeighami, Samaneh; Haghpanah, Sezaneh; Karimi, Mehran

2017-01-01

The goal of this study was to compare heart function and arrhythmia in clinically asymptomatic patients with beta thalassemia intermedia and beta thalassemia major. In this cross-sectional study, 60 patients with beta thalassemia major and 60 patients with beta thalassemia intermedia who had clinically no symptoms of arrhythmia and clinically normal heart function were evaluated using 24-hour ambulatory electrocardiogram monitoring and echocardiography. For data analysis SPSS ver.20 software was used. A P-value of less than 0.05 was considered statistically significant. The mean age of the beta thalassemia intermedia patients was 24.18 ± 7.9 years and the mean age in beta thalassemia major was 24.38 ± 7.7 years (P>0.05). Premature atrial contractions (PACs) were observed in 14 (23.3%) patients with beta thalassemia intermedia and in 22 (36.6%) beta thalassemia major patients. Premature ventricular contractions (PVCs) were detected in 8 (13.3%) patients in the beta thalassemia intermediate group and 16 (26.6) patients in the beta thalassemia major group, respectively. The left ventricular diastolic dimension, end-diastolic volume, and stroke volume were significantly higher in beta thalassemia intermedia group (Pintermedia group. Both atrial and ventricular arrhythmias were more common in the beta thalassemia major group. Higher end-diastolic volume and stroke volume were detected in the beta thalassemia intermedia group. Pulmonary acceleration time was lower in the beta thalassemia intermedia group, which can be an indicator of higher pulmonary pressure.

An Adaptive Particle Weighting Strategy for ECG Denoising Using Marginalized Particle Extended Kalman Filter: An Evaluation in Arrhythmia Contexts.

Science.gov (United States)

Hesar, Hamed Danandeh; Mohebbi, Maryam

2017-11-01

Model-based Bayesian frameworks have a common problem in processing electrocardiogram (ECG) signals with sudden morphological changes. This situation often happens in the case of arrhythmias where ECGs do not obey the predefined state models. To solve this problem, in this paper, a model-based Bayesian denoising framework is proposed using marginalized particle-extended Kalman filter (MP-EKF), variational mode decomposition, and a novel fuzzy-based adaptive particle weighting strategy. This strategy helps MP-EKF to perform well even when the morphology of signal does not comply with the predefined dynamic model. In addition, this strategy adapts MP-EKF's behavior to the acquired measurements in different input signal to noise ratios (SNRs). At low input SNRs, this strategy decreases the particles' trust level to the measurements while increasing their trust level to a synthetic ECG constructed with the feature parameters of ECG dynamic model. At high input SNRs, the particles' trust level to the measurements is increased and the trust level to synthetic ECG is decreased. The proposed method was evaluated on MIT-BIH normal sinus rhythm database and compared with EKF/EKS frameworks and previously proposed MP-EKF. It was also evaluated on ECG segments extracted from MIT-BIH arrhythmia database, which contained ventricular and atrial arrhythmia. The results showed that the proposed algorithm had a noticeable superiority over benchmark methods from both SNR improvement and multiscale entropy based weighted distortion (MSEWPRD) viewpoints at low input SNRs.

Arrhythmias and sudden death among older children and young adults following tetralogy of Fallot repair in the current era: are previously reported risk factors still applicable?

Science.gov (United States)

Arya, Swati; Kovach, Julie; Singh, Harinder; Karpawich, Peter P

2014-01-01

Young adult patients (pts) with repaired tetralogy of Fallot (TOF) remain at risk for arrhythmias (Ar) and sudden cardiac death (SCD). Based on past studies with earlier pt subsets, Ar/SCD events were associated with right ventricular (RV) systolic pressures >60 mm Hg, outflow tract gradients >20 mm Hg, and QRS duration >180 ms. However, there are limited recent studies to evaluate these risk factors in the current patient generation. Patients with TOF followed over the past 50 years were grouped by presence of any arrhythmias (group 1), absence of arrhythmias (group 2), and presence of SCD or significant ventricular arrhythmias (group 3) and correlated with current pt age, gender, age at repair, repair types, echocardiogram, cardiac magnetic resonance imaging, electrocardiogram/Holter, hemodynamics, and electrophysiology findings. Of 109 pts, 52 were male aged 17-58 years. Of these, 59 (54%) had Ar, two of whom had SCD. These 59 pts were chronologically older at the time of analysis, with repair at an older age and wider QRS duration (78-240, mean 158 ms) when compared with those without Ar. However, there was no correlation with surgical era, surgical repair, gender, RV pressure >60 mm Hg, right ventricular outflow tract gradient >20 mm Hg, or RV end-diastolic volume on CMRI. Ar/SCD risk continues to correlate with repair age and advancing pt age. QRS duration is longer in these patients but at a shorter interval (mean 158 ms) and less RV pressure (mean 43 mm Hg) than previously reported. In the current TOF patient generation, neither surgical era, type of repair, RV outflow gradient nor RV volume correlate with Ar/SCD. Electrophysiologic testing to verify and identify arrhythmias remains clinically effective. © 2013 Wiley Periodicals, Inc.

Use of the Surface Electrocardiogram to Define the Nature of Challenging Arrhythmias.

Science.gov (United States)

Singh, David K; Peter, C Thomas

2016-03-01

Despite unprecedented advances in technology, the electrocardiogram (ECG) remains essential to the practice of modern electrophysiology. Since its emergence at the turn of the nineteenth century, the form of the ECG has changed little. What has changed is our ability to understand the complex mechanisms that underlie various arrhythmias. In this article, the authors review several important principles of ECG interpretation by providing illustrative tracings. The authors also highlight several important concepts that be can used in ECG analysis. There are several fundamental principles that should be considered in ECG interpretation. Copyright © 2016 Elsevier Inc. All rights reserved.

Energetic lanthanide complexes: coordination chemistry and explosives applications

International Nuclear Information System (INIS)

Manner, V W; Barker, B J; Sanders, V E; Laintz, K E; Scott, B L; Preston, D N; Sandstrom, M; Reardon, B L

2014-01-01

Metals are generally added to organic molecular explosives in a heterogeneous composite to improve overall heat and energy release. In order to avoid creating a mixture that can vary in homogeneity, energetic organic molecules can be directly bonded to high molecular weight metals, forming a single metal complex with Angstrom-scale separation between the metal and the explosive. To probe the relationship between the structural properties of metal complexes and explosive performance, a new series of energetic lanthanide complexes has been prepared using energetic ligands such as NTO (5-nitro-2,4-dihydro-1,2,4-triazole-3-one). These are the first examples of lanthanide NTO complexes where no water is coordinated to the metal, demonstrating novel control of the coordination environment. The complexes have been characterized by X-ray crystallography, NMR and IR spectroscopies, photoluminescence, and sensitivity testing. The structural and energetic properties are discussed in the context of enhanced blast effects and detection. Cheetah calculations have been performed to fine-tune physical properties, creating a systematic method for producing explosives with 'tailor made' characteristics. These new complexes will be benchmarks for further study in the field of metalized high explosives.

[Surgery of refractory ischemic arrhythmia].

Science.gov (United States)

Viganò, M; Graffigna, A; Salerno, G

1992-03-01

Since June 1980, 138 patients have undergone surgical treatment for refractory ventricular tachycardia due to ischemic heart disease. Electrically guided surgical ablation (EGSA) of the focus was performed in 117 patients, while 14 patients underwent application of automatic implantable cardioverter-defibrillator (AICD), and 8 patients underwent heart transplantation. During the whole period considered, among the EGSA patients an operative mortality of 13 patients was observed (11.4%), with a late mortality of another 14 patients (13.4%). Two early and six late recurrences were described, and 4 cases of sudden or unexplained death, with 2 cases clearly due to an arrhythmic event. Multivariate analysis showed preoperative ejection fraction lower than 25% as a powerful predictor of early mortality (32% vs 0%). Actuarial survival rate of patients with LVEF lower than 25% was 67 +/- 12% vs 95 +/- 2% at one year and 37 +/- 25% vs 94 +/- 8% at 8 years. A high operative mortality was then observed in patients who underwent aneurysmectomy alone or visually guided procedures as compared to electrically guided procedures (75% or 3 deaths out of 4 patients vs 8.5% or 10 out of 113 patients, respectively). Patients who received an AICD with or without associated procedures showed 1 case of in-hospital mortality and no late mortality; in 6 patients at least one shock was delivered; in two patients the AICD was implanted during an EGSA procedure, due to multiple or difficult origins of the arrhythmias. Of patients who underwent heart transplantation one case of later mortality was observed due to malignancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Biogas - energetical and environmental point of view

International Nuclear Information System (INIS)

Skele, A.; Upitis, A.; Kristapsons, M.; Goizevskis, O.; Ziemelis, I.

2003-01-01

Energy sector has been one of the most important priorities since reestablishment of independence of Latvia. The deficiency of energy resources in Latvia has created a need to assess all the possibilities to utilise all possibilities to utilise all the energy resources, including the biological ones, to motivate the trends in the development of energetic in Latvia. A huge non-utilised reserve in Latvia is methane fermentation of organic agricultural and municipal residue and sewage from food industry. The organic mass of solid and liquid waste of different origin and its energetic potential for rural region have been investigated. The work deals with an integrated system of the utilisation of agricultural waste with the anaerobic (biogas) and the thermal processes. Presently the anaerobic waste utilisation, in combination with the production of biogas and organic fertiliser, is considered as one of the energetically most efficient and environment-friendly ways of organic fertiliser utilisation (authors)

Energetic ions and electrons and their acceleration processes in the magnetotail

International Nuclear Information System (INIS)

Scholer, M.

1984-01-01

Observations of energetic particle fluxes in the geomagnetic tail show that these particles exhibit a bursty appearance on all time scales. Often, however, the bursty appearance is merely due to multiple entries and exits of the spacecraft into and out of the plasma sheet which always contains varying fluxes of energetic particles. Observations of the suprathermal and high-energy component of the plasma sheet are discussed, and observations are presented of energetic particle bursts in the plasma sheet proper, which may be due to a locally ongoing acceleration process. Also discussed are energetic particle phenomena occurring near the edge of the plasma sheet, either during thinning or during recovery. Some recent results from the ISEE 3 deep tail mission bearing on energetic particle acceleration are presented, and the present status of the theory of particle acceleration within the magnetotail is briefly reviewed. 40 references

Short-term fasting reduces the extent of myocardial infarction and incidence of reperfusion arrhythmias in rats

Czech Academy of Sciences Publication Activity Database

Šnorek, M.; Hodyc, D.; Šedivý, V.; Ďurišová, J.; Skoumalová, A.; Wilhelm, J.; Neckář, Jan; Kolář, František; Herget, J.

2012-01-01

Roč. 61, č. 6 (2012), s. 567-574 ISSN 0862-8408 R&D Projects: GA MŠk(CZ) 1M0510; GA ČR(CZ) GA305/08/0108 Institutional research plan: CEZ:AV0Z5011922 Keywords : myocardial ischemia/reperfusion * arrhythmias * infarction * fasting * ketone bodies Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery Impact factor: 1.531, year: 2012

Recent progress of hybrid simulation for energetic particles and MHD

International Nuclear Information System (INIS)

Todo, Y.

2013-01-01

Several hybrid simulation models have been constructed to study the evolution of Alfven eigenmodes destabilized by energetic particles. Recent hybrid simulation results of energetic particle driven instabilities are presented in this paper. (J.P.N.)

Internal Transport Barrier Driven by Redistribution of Energetic Ions

International Nuclear Information System (INIS)

Wong, K.L.; Heidbrink, W.W.; Ruskov, E.; Petty, C.C.; Greenfield, C.M.; Nazikian, R.; Budny, R.

2004-01-01

Alfven instabilities excited by energetic ions are used as a means to reduce the central magnetic shear in a tokamak via redistribution of energetic ions. When the central magnetic shear is low enough, ballooning modes become stable for any plasma pressure gradient and an internal transport barrier (ITB) with a steep pressure gradient can exist. This mechanism can sustain a steady-state ITB as demonstrated by experimental data from the DIII-D tokamak. It can also produce a shear in toroidal and poloidal plasma rotation. Possible application of this technique to use the energetic alpha particles for improvement of burning plasma performance is discussed

Bcl-xL regulates mitochondrial energetics by stabilizing the inner membrane potential.

Science.gov (United States)

Chen, Ying-Bei; Aon, Miguel A; Hsu, Yi-Te; Soane, Lucian; Teng, Xinchen; McCaffery, J Michael; Cheng, Wen-Chih; Qi, Bing; Li, Hongmei; Alavian, Kambiz N; Dayhoff-Brannigan, Margaret; Zou, Shifa; Pineda, Fernando J; O'Rourke, Brian; Ko, Young H; Pedersen, Peter L; Kaczmarek, Leonard K; Jonas, Elizabeth A; Hardwick, J Marie

2011-10-17

Mammalian Bcl-x(L) protein localizes to the outer mitochondrial membrane, where it inhibits apoptosis by binding Bax and inhibiting Bax-induced outer membrane permeabilization. Contrary to expectation, we found by electron microscopy and biochemical approaches that endogenous Bcl-x(L) also localized to inner mitochondrial cristae. Two-photon microscopy of cultured neurons revealed large fluctuations in inner mitochondrial membrane potential when Bcl-x(L) was genetically deleted or pharmacologically inhibited, indicating increased total ion flux into and out of mitochondria. Computational, biochemical, and genetic evidence indicated that Bcl-x(L) reduces futile ion flux across the inner mitochondrial membrane to prevent a wasteful drain on cellular resources, thereby preventing an energetic crisis during stress. Given that F(1)F(O)-ATP synthase directly affects mitochondrial membrane potential and having identified the mitochondrial ATP synthase β subunit in a screen for Bcl-x(L)-binding partners, we tested and found that Bcl-x(L) failed to protect β subunit-deficient yeast. Thus, by bolstering mitochondrial energetic capacity, Bcl-x(L) may contribute importantly to cell survival independently of other Bcl-2 family proteins.

Energetic Particles: From Sun to Heliosphere - and vice versa

Science.gov (United States)

Wimmer-Schweingruber, R. F.; Rodriguez-Pacheco, J.; Boden, S.; Boettcher, S. I.; Cernuda, I.; Dresing, N.; Drews, C.; Droege, W.; Espinosa Lara, F.; Gomez-Herrero, R.; Heber, B.; Ho, G. C.; Klassen, A.; Kulkarni, S. R.; Mann, G. J.; Martin-Garcia, C.; Mason, G. M.; Panitzsch, L.; Prieto, M.; Sanchez, S.; Terasa, C.; Eldrum, S.

2017-12-01

Energetic particles in the heliosphere can be measured at their elevated energetic status after three processes: injection, acceleration, and transport. Suprathermal seed particles have speeds well above the fast magnetosonic speed in the solar wind frame of reference and can vary from location to location and within the solar activity cycle. Acceleration sites include reconnecting current sheets in solar flares or magnetspheric boundaries, shocks in the solar corona, heliosphere and a planetary obstacles, as well as planetary magnetospheres. Once accelerated, particles are transported from the acceleration site into and through the heliosphere. Thus, by investigating properties of energetic particles such as their composition, energy spectra, pitch-angle distribution, etc. one can attempt to distinguish their origin or injection and acceleration site. This in turn allows us to better understand transport effects whose underlying microphysics is also a key ingredient in the acceleration of particles. In this presentation we will present some clear examples which link energetic particles from their observing site to their source locations. These include Jupiter electrons, singly-charged He ions from CIRs, and 3He from solar flares. We will compare these examples with the measurement capabilities of the Energetic Particle Detector (EPD) on Solar Orbiter and consider implications for the key science goal of Solar Orbiter and Solar Proble Plus - How the Sun creates and controls the heliosphere.

Short-term Effects of High-Dose Caffeine on Cardiac Arrhythmias in Patients With Heart Failure: A Randomized Clinical Trial.

Science.gov (United States)

Zuchinali, Priccila; Souza, Gabriela C; Pimentel, Maurício; Chemello, Diego; Zimerman, André; Giaretta, Vanessa; Salamoni, Joyce; Fracasso, Bianca; Zimerman, Leandro I; Rohde, Luis E

2016-12-01

The presumed proarrhythmic action of caffeine is controversial. Few studies have assessed the effect of high doses of caffeine in patients with heart failure due to left ventricular systolic dysfunction at high risk for ventricular arrhythmias. To compare the effect of high-dose caffeine or placebo on the frequency of supraventricular and ventricular arrhythmias, both at rest and during a symptom-limited exercise test. Double-blinded randomized clinical trial with a crossover design conducted at the heart failure and cardiac transplant clinic of a tertiary-care university hospital. The trial included patients with chronic heart failure with moderate-to-severe systolic dysfunction (left ventricular ejection fraction capsules, in addition to 5 doses of 100 mL decaffeinated coffee at 1-hour intervals, for a total of 500 mg of caffeine or placebo during a 5-hour protocol. After a 1-week washout period, the protocol was repeated. Number and percentage of ventricular and supraventricular premature beats assessed by continuous electrocardiographic monitoring. We enrolled 51 patients (37 [74%] male; mean [SD] age, 60.6 [10.9] years) with predominantly moderate-to-severe left ventricular systolic dysfunction (mean [SD] left ventricular ejection fraction, 29% [7%]); 31 [61%] had an implantable cardioverter-defibrillator device. No significant differences between the caffeine and placebo groups were observed in the number of ventricular (185 vs 239 beats, respectively; P = .47) and supraventricular premature beats (6 vs 6 beats, respectively; P = .44), as well as in couplets, bigeminal cycles, or nonsustained tachycardia during continuous electrocardiographic monitoring. Exercise test-derived variables, such as ventricular and supraventricular premature beats, duration of exercise, estimated peak oxygen consumption, and heart rate, were not influenced by caffeine ingestion. We observed no increases in ventricular premature beats (91 vs 223 vs 207 beats, respectively

Pit-a-Pat: A Smart Electrocardiogram System for Detecting Arrhythmia.

Science.gov (United States)

Park, Juyoung; Lee, Kuyeon; Kang, Kyungtae

2015-10-01

Electrocardiogram (ECG) telemonitoring is one of the most promising applications of medical telemetry. However, previous approaches to ECG telemonitoring have largely relied on public databases of ECG results. In this article we propose a smart ECG system called Pit-a-Pat, which extracts features from ECG signals and detects arrhythmia. It is designed to run on an Android™ (Google, Mountain View, CA) device, without requiring modifications to other software. We implemented the Pit-a-Pat system using a commercial ECG device, and the experimental results demonstrate the effectiveness and accuracy of Pit-a-Pat for monitoring the ECG signal and analyzing the cardiac activity of a mobile patient. The proposed system allows monitoring of cardiac activity with automatic analysis, thereby providing a convenient, inexpensive, and ubiquitous adjunct to personal healthcare.

Resting respiratory sinus arrhythmia is associated with tonic positive emotionality.

Science.gov (United States)

Oveis, Christopher; Cohen, Adam B; Gruber, June; Shiota, Michelle N; Haidt, Jonathan; Keltner, Dacher

2009-04-01

Resting respiratory sinus arrhythmia (RSAREST) indexes important aspects of individual differences in emotionality. In the present investigation, the authors address whether RSAREST is associated with tonic positive or negative emotionality, and whether RSAREST relates to phasic emotional responding to discrete positive emotion-eliciting stimuli. Across an 8-month, multiassessment study of first-year university students (n = 80), individual differences in RSAREST were associated with positive but not negative tonic emotionality, assessed at the level of personality traits, long-term moods, the disposition toward optimism, and baseline reports of current emotional states. RSAREST was not related to increased positive emotion, or stimulus-specific emotion, in response to compassion-, awe-, or pride-inducing stimuli. These findings suggest that resting RSA indexes aspects of a person's tonic positive emotionality. (c) 2009 APA, all rights reserved.

Flecainide reduces ventricular arrhythmias via a mechanism that differs from that of β-blockers in catecholaminergic polymorphic ventricular tachycardia

Directory of Open Access Journals (Sweden)

Kenichi Dochi

2013-10-01

Conclusion: Flecainide effectively reduced ventricular arrhythmias via a mechanism that differs from that of β-blockers in genotype-positive patients with CPVT. The specific effects of flecainide may be critical in the improvement noted in the patients' ability to perform daily activities.

A Novel Nonsense Variant in Nav1.5 Cofactor MOG1 Eliminates Its Sodium Current Increasing Effect and May Increase the Risk of Arrhythmias

DEFF Research Database (Denmark)

Olesen, Morten S; Jensen, Niels F; Holst, Anders G

2011-01-01

at a lower frequency (1.8% vs 0.4%, P = 0.078). Electrophysiological investigation showed that the p.E61X variant completely eliminates the sodium current-increasing effect of MOG1 and thereby causes loss of function in the sodium current. When mimicking heterozygosity by coexpression of Nav1.5 with wild......BACKGROUND: The protein MOG1 is a cofactor of the cardiac sodium channel, Nav1.5. Overexpression of MOG1 in Nav1.5-expressing cells increases sodium current markedly. Mutations in the genes encoding Nav1.5 and its accessory proteins have been associated with cardiac arrhythmias of significant...... and 23 were patients with Brugada syndrome. The effect of one variant was investigated functionally by patch-clamping CHO-K1 cells coexpressing Nav1.5 with MOG1. RESULTS: We uncovered a novel heterozygous nonsense variant, c.181G>T (p.E61X), that, however, was also present in control subjects, albeit...

Electron-beam CT coronary angiography in the patients with high heart rate arrhythmia or pacemaker

International Nuclear Information System (INIS)

Dong Zhi; Zhu Jiemin; Liu Zhe; Liu Junbo; Li Youjie; Qi Ji

2006-01-01

Objective: To report the clinical applicability of coronary angiography for patients with high heart rate, arrhythmia or cardiac pacing using the new-generation of electron-beam CT (e-Speed). Methods: EBCT (GE e-Speed) coronary angiography was performed in 36 eases (male 27, female 9, mean age 58), including the heart rate more than 90 bpm in 20 patients, frequent ectopic beats in 11 cases, implantation of cardiac pacemaker in 4 patients and the unacceptable MSCT image quality due to variability of interscan heart rate (from 82 bpm to 104 bpm) in 1 case. After volume data set was acquired using spiral mode with prospective ECG-gating, the reconstructions of MIP, CPR, VR and Cine were performed. The VR quality was evaluated using a five-point scale. Results: The quality of coronary imaging in all of 36 cases were acceptable. The total visualization rate of coronary artery branches was 80.0%. Left main, left anterior artery and right coronary artery were visualized in all patients and in 94.3% of all cases circumflex artery were visible. Conclusion: EBCT (e-Speed) is applicable in noninvasive coronary angiography for patients with high heart rate, arrhythmia or implanted cardiac pacemaker', and this examination can obtain satisfied diagnosis. (authors)

Therapeutic concentrations of mitoxantrone elicit energetic imbalance in H9c2 cells as an earlier event.

Science.gov (United States)

Rossato, Luciana Grazziotin; Costa, Vera Marisa; Vilas-Boas, Vânia; de Lourdes Bastos, Maria; Rolo, Anabela; Palmeira, Carlos; Remião, Fernando

2013-12-01

Mitoxantrone (MTX) is a chemotherapeutic agent that emerged as an alternative to anthracycline therapy. However, MTX also causes late cardiotoxicity, being oxidative stress and mitochondrial-impaired function proposed as possible mechanisms. This work aimed to investigate the relevance of these mechanisms to the MTX toxicity in H9c2 cells, using therapeutic concentrations. The observed cytotoxicity of MTX was time and concentration dependent in both lactate dehydrogenase leakage assay and MTT reduction assay. Two therapeutic concentrations (100 nM and 1 μM) and three time points were selected (24, 48, and 96 h) for further studies. Both MTX concentrations caused a significant increase in caspase-3 activity, which was not prevented by inhibiting MTX CYP450-metabolism. Significant decreases were observed in the total and reduced glutathione levels only in MTX 100 nM at 96 h; however, neither alterations in oxidized glutathione nor increases in the malondialdehyde levels were observed at any time or concentrations tested. On the other hand, changes in the intracellular ATP levels, mitochondrial membrane potential, and intracellular calcium levels were observed in both concentrations and all time tested. Noteworthy, decreased levels of ATP-synthase expression and activity and increases in the reactive species generation were observed at 96 h in both working concentrations. However, the radical scavenger N-acetylcysteine or the mitochondrial function enhancer L-carnitine did not prevent MTX cytotoxicity. Thus, this work evidenced the early MTX-induced energetic crisis as a possible key factor in the cell injury.

Energetics of dislocation transformations in hcp metals

International Nuclear Information System (INIS)

Wu, Zhaoxuan; Yin, Binglun; Curtin, W.A.

2016-01-01

Dislocation core structures of hcp metals are highly complex and differ significantly among the hcp family. Some dislocations undergo unconventional transformations that have significant effects on the material plastic flow. Here, the energetics of dislocation dissociations are analyzed in a general anisotropic linear elastic theory framework for transformations in which changes in the partial Burgers vectors are small. Quantitative analyses on various transformations are made using DFT-computed stacking fault energies and partial Burgers vectors. Specifically, possible transformations of the mixed, edge, and screw 〈c+a〉 and screw 〈a〉 dislocations in 6 hcp metals (Mg, Ti, Zr, Re, Zn, Cd) are studied. Climb dissociation of mixed or edge 〈c+a〉 dislocations to the Basal plane is energetically favorable in all 6 metals and thus only limited by thermal activation. The 〈c+a〉 screw dislocation is energetically preferable on Pyramidal I for Ti, Zr, and Re, and on Pyramidal II for Zn and Cd. In Mg, the energy difference between screw 〈c+a〉 on Pyramidal I and II planes is small, suggesting relatively easy cross-slip. For the screw 〈a〉, Basal dissociation is energetically favorable in Mg, Re, Zn and Cd, while Prism dissociation is strongly favorable in Ti and Zr. Only Ti, Zr and Re show a metastable state for dissociation on the Prism plane, and the energy difference between screw 〈a〉 on the Prism and Pyramidal I planes is relatively small in all systems, suggesting relatively easy cross-slip of 〈a〉 in Ti and Zr. The elastic analysis thus provides a single framework able to capture the controlling energetics for different dissociations and slip systems in hcp metals. When the calculated energy differences are very small, the results point to the need for detailed modeling of the atomistic core structure. Moreover, the analyses rationalize broad experimental observations on dominant slip systems and dislocation behaviours, and provide

Plakophilin-2 c.419C>T and risk of heart failure and arrhythmias in the general population

DEFF Research Database (Denmark)

Christensen, Alex Hørby; Kamstrup, Pia Rørbœk; Gandjbakhch, Estelle

2016-01-01

A rare genetic variant in the desmosomal gene plakophilin-2 (PKP2) c.419C>T(p.(S140F)) has repeatedly been identified in patients with dilated cardiomyopathy (DCM) and arrhythmogenic right ventricular cardiomyopathy (ARVC). Whether this is a disease-causing variant remains highly controversial. We...... ratios as a function of c.419C>T genotype were 2.11 (0.50-8.99) for ARVC, 0.72 (0.16-3.28) for hypertrophic cardiomyopathy (HCM)/DCM, and 1.28 (0.46-3.54) for end points combined. Third, in in vitro studies cellular localization of plakophilin-2, plakoglobin, connexin-43, or N-cadherin were similar...... in cells transfected with wild-type or mutant plakophilin-2. In conclusion, combining epidemiological data, with data on patients referred for genetic testing for ARVC or HCM/DCM, and data from in vitro studies, PKP2 c.419C>T did not associate with heart failure, arrhythmias, or premature death, with ARVC...

Analysis and verification of a prediction model of solar energetic proton events

Science.gov (United States)

Wang, J.; Zhong, Q.

2017-12-01

The solar energetic particle event can cause severe radiation damages near Earth. The alerts and summary products of the solar energetic proton events were provided by the Space Environment Prediction Center (SEPC) according to the flux of the greater than 10 MeV protons taken by GOES satellite in geosynchronous orbit. The start of a solar energetic proton event is defined as the time when the flux of the greater than 10 MeV protons equals or exceeds 10 proton flux units (pfu). In this study, a model was developed to predict the solar energetic proton events, provide the warning for the solar energetic proton events at least minutes in advance, based on both the soft X-ray flux and integral proton flux taken by GOES. The quality of the forecast model was measured against verifications of accuracy, reliability, discrimination capability, and forecast skills. The peak flux and rise time of the solar energetic proton events in the six channels, >1MeV, >5 MeV, >10 MeV, >30 MeV, >50 MeV, >100 MeV, were also simulated and analyzed.

Dual scattering foil design for poly-energetic electron beams

International Nuclear Information System (INIS)

Kainz, K K; Antolak, J A; Almond, P R; Bloch, C D; Hogstrom, K R

2005-01-01

The laser wakefield acceleration (LWFA) mechanism can accelerate electrons to energies within the 6-20 MeV range desired for therapy application. However, the energy spectrum of LWFA-generated electrons is broad, on the order of tens of MeV. Using existing laser technology, the therapeutic beam might require a significant energy spread to achieve clinically acceptable dose rates. The purpose of this work was to test the assumption that a scattering foil system designed for a mono-energetic beam would be suitable for a poly-energetic beam with a significant energy spread. Dual scattering foil systems were designed for mono-energetic beams using an existing analytical formalism based on Gaussian multiple-Coulomb scattering theory. The design criterion was to create a flat beam that would be suitable for fields up to 25 x 25 cm 2 at 100 cm from the primary scattering foil. Radial planar fluence profiles for poly-energetic beams with energy spreads ranging from 0.5 MeV to 6.5 MeV were calculated using two methods: (a) analytically by summing beam profiles for a range of mono-energetic beams through the scattering foil system, and (b) by Monte Carlo using the EGS/BEAM code. The analytic calculations facilitated fine adjustments to the foil design, and the Monte Carlo calculations enabled us to verify the results of the analytic calculation and to determine the phase-space characteristics of the broadened beam. Results showed that the flatness of the scattered beam is fairly insensitive to the width of the input energy spectrum. Also, results showed that dose calculated by the analytical and Monte Carlo methods agreed very well in the central portion of the beam. Outside the useable field area, the differences between the analytical and Monte Carlo results were small but significant, possibly due to the small angle approximation. However, these did not affect the conclusion that a scattering foil system designed for a mono-energetic beam will be suitable for a poly-energetic

Inferring repeat-protein energetics from evolutionary information.

Directory of Open Access Journals (Sweden)

Rocío Espada

2017-06-01

Full Text Available Natural protein sequences contain a record of their history. A common constraint in a given protein family is the ability to fold to specific structures, and it has been shown possible to infer the main native ensemble by analyzing covariations in extant sequences. Still, many natural proteins that fold into the same structural topology show different stabilization energies, and these are often related to their physiological behavior. We propose a description for the energetic variation given by sequence modifications in repeat proteins, systems for which the overall problem is simplified by their inherent symmetry. We explicitly account for single amino acid and pair-wise interactions and treat higher order correlations with a single term. We show that the resulting evolutionary field can be interpreted with structural detail. We trace the variations in the energetic scores of natural proteins and relate them to their experimental characterization. The resulting energetic evolutionary field allows the prediction of the folding free energy change for several mutants, and can be used to generate synthetic sequences that are statistically indistinguishable from the natural counterparts.

Respiratory sinus arrhythmia as a measure of cognitive workload.

Science.gov (United States)

Muth, Eric R; Moss, Jason D; Rosopa, Patrick J; Salley, James N; Walker, Alexander D

2012-01-01

The current standard for measuring cognitive workload is the NASA Task-load Index (TLX) questionnaire. Although this measure has a high degree of reliability, diagnosticity, and sensitivity, a reliable physiological measure of cognitive workload could provide a non-invasive, objective measure of workload that could be tracked in real or near real-time without interrupting the task. This study investigated changes in respiratory sinus arrhythmia (RSA) during seven different sub-sections of a proposed selection test for Navy aviation and compared them to changes reported on the NASA-TLX. 201 healthy participants performed the seven tasks of the Navy's Performance Based Measure. RSA was measured during each task and the NASA-TLX was administered after each task. Multi-level modeling revealed that RSA significantly predicted NASA-TLX scores. A moderate within-subject correlation was also found between RSA and NASA TLX scores. The findings support the potential development of RSA as a real-time measure of cognitive workload. Copyright © 2011. Published by Elsevier B.V.

Modeling Thermal Ignition of Energetic Materials

National Research Council Canada - National Science Library

Gerri, Norman J; Berning, Ellen

2004-01-01

This report documents an attempt to computationally simulate the mechanics and thermal regimes created when a threat perforates an armor envelope and comes in contact with stowed energetic material...

Ursodeoxycholic acid prevents ventricular conduction slowing and arrhythmia by restoring T-type calcium current in fetuses during cholestasis

Science.gov (United States)

Adeyemi, Oladipupo; Alvarez-Laviada, Anita; Schultz, Francisca; Ibrahim, Effendi; Trauner, Michael; Williamson, Catherine; Glukhov, Alexey V.

2017-01-01

Background Increased maternal serum bile acid concentrations in intrahepatic cholestasis of pregnancy (ICP) are associated with fetal cardiac arrhythmias. Ursodeoxycholic acid (UDCA) has been shown to demonstrate anti-arrhythmic properties via preventing ICP-associated cardiac conduction slowing and development of reentrant arrhythmias, although the cellular mechanism is still being elucidated. Methods High-resolution fluorescent optical mapping of electrical activity and electrocardiogram measurements were used to characterize effects of UDCA on one-day-old neonatal and adult female Langendorff-perfused rat hearts. ICP was modelled by perfusion of taurocholic acid (TC, 400μM). Whole-cell calcium currents were recorded from neonatal rat and human fetal cardiomyocytes. Results TC significantly prolonged the PR interval by 11.0±3.5% (P<0.05) and slowed ventricular conduction velocity (CV) by 38.9±5.1% (P<0.05) exclusively in neonatal and not in maternal hearts. A similar CV decline was observed with the selective T-type calcium current (ICa,T) blocker mibefradil 1μM (23.0±6.2%, P<0.05), but not with the L-type calcium current (ICa,L) blocker nifedipine 1μM (6.9±6.6%, NS). The sodium channel blocker lidocaine (30μM) reduced CV by 60.4±4.5% (P<0.05). UDCA co-treatment was protective against CV slowing induced by TC and mibefradil, but not against lidocaine. UDCA prevented the TC-induced reduction in the ICa,T density in both isolated human fetal (−10.2±1.5 versus −5.5±0.9 pA/pF, P<0.05) and neonatal rat ventricular myocytes (−22.3±1.1 versus −9.6±0.8 pA/pF, P<0.0001), whereas UDCA had limited efficacy on the ICa,L. Conclusion Our findings demonstrate that ICa,T plays a significant role in ICP-associated fetal cardiac conduction slowing and arrhythmogenesis, and is an important component of the fetus-specific anti-arrhythmic activity of UDCA. PMID:28934223

Ursodeoxycholic acid prevents ventricular conduction slowing and arrhythmia by restoring T-type calcium current in fetuses during cholestasis.

Directory of Open Access Journals (Sweden)

Oladipupo Adeyemi

Full Text Available Increased maternal serum bile acid concentrations in intrahepatic cholestasis of pregnancy (ICP are associated with fetal cardiac arrhythmias. Ursodeoxycholic acid (UDCA has been shown to demonstrate anti-arrhythmic properties via preventing ICP-associated cardiac conduction slowing and development of reentrant arrhythmias, although the cellular mechanism is still being elucidated.High-resolution fluorescent optical mapping of electrical activity and electrocardiogram measurements were used to characterize effects of UDCA on one-day-old neonatal and adult female Langendorff-perfused rat hearts. ICP was modelled by perfusion of taurocholic acid (TC, 400μM. Whole-cell calcium currents were recorded from neonatal rat and human fetal cardiomyocytes.TC significantly prolonged the PR interval by 11.0±3.5% (P<0.05 and slowed ventricular conduction velocity (CV by 38.9±5.1% (P<0.05 exclusively in neonatal and not in maternal hearts. A similar CV decline was observed with the selective T-type calcium current (ICa,T blocker mibefradil 1μM (23.0±6.2%, P<0.05, but not with the L-type calcium current (ICa,L blocker nifedipine 1μM (6.9±6.6%, NS. The sodium channel blocker lidocaine (30μM reduced CV by 60.4±4.5% (P<0.05. UDCA co-treatment was protective against CV slowing induced by TC and mibefradil, but not against lidocaine. UDCA prevented the TC-induced reduction in the ICa,T density in both isolated human fetal (-10.2±1.5 versus -5.5±0.9 pA/pF, P<0.05 and neonatal rat ventricular myocytes (-22.3±1.1 versus -9.6±0.8 pA/pF, P<0.0001, whereas UDCA had limited efficacy on the ICa,L.Our findings demonstrate that ICa,T plays a significant role in ICP-associated fetal cardiac conduction slowing and arrhythmogenesis, and is an important component of the fetus-specific anti-arrhythmic activity of UDCA.

Energetic adaptations persist after bariatric surgery in severely obese adolescents

Science.gov (United States)

Energetic adaptations induced by bariatric surgery have not been studied in adolescents or for extended periods postsurgery. Energetic, metabolic, and neuroendocrine responses to Roux-en-Y gastric bypass (RYGB) surgery were investigated in extremely obese adolescents. At baseline and at 1.5, 6, and...

Effect of Trapped Energetic Ions on MHD Activity in Spherical Tori

International Nuclear Information System (INIS)

White, R.B.; Kolesnichenko, Ya.I.; Lutsenko, V.V.; Marchenko, V.S.

2002-01-01

It is shown that the increase of beta (the ratio of plasma pressure to the magnetic field pressure) may change the character of the influence of trapped energetic ions on MHD stability in spherical tori. Namely, the energetic ions, which stabilize MHD modes (such as the ideal-kink mode, collisionless tearing mode, and semi-collisional tearing mode) at low beta, have a destabilizing influence at high beta unless the radial distribution of the energetic ions is very peaked

The HZE radiation problem. [highly-charged energetic galactic cosmic rays

Science.gov (United States)

Schimmerling, Walter

1990-01-01

Radiation-exposure limits have yet to be established for missions envisioned in the framework of the Space Exploration Initiative. The radiation threat outside the earth's magnetosphere encompasses protons from solar particle events and the highly charged energetic particles constituting galactic cosmic rays; radiation biology entails careful consideration of the extremely nonuniform patterns of such particles' energy deposition. The ability to project such biological consequences of exposure to energetic particles as carcinogenicity currently involves great uncertainties from: (1) different regions of space; (2) the effects of spacecraft structures; and (3) the dose-effect relationships of single traversals of energetic particles.

Arrhythmia and conduction disorders in acute inferior myocardial infarction with right ventricular involvement

International Nuclear Information System (INIS)

Samadikhah, J.; Hakim, S.H.; Azarfarin, R.; Ghaffari, S.

2007-01-01

To assess the prognostic impact of Right Ventricular (RV) myocardial involvement in patients with inferior MI. One hundred seventy patients who were admitted to cardiac care unit of Madani Heart Hospital, Tabriz, Iran with the diagnosis of inferior MI with (group 1) or without (group 2) simultaneous involvement of RV were studied from 2005 to 2006. Patients presenting within 12 hours of symptom onset were eligible for inclusion. Those with simultaneous Anterior wall MI, patients undergoing primary percutaneous transluminal coronary angioplasty and those with renal impairment (creatinine >2 mg/dl) were excluded. Eighty eight percent of the patients with RVMI and 75% with isolated inferior MI had some type of arrhythmia. AV block occurred in 42% of the infarctions with RV involvement and only in 29% of the control group. Intra ventricular conduction disturbance (IVCD) also were more frequent in RVMI (29.4% VS 13.1%, p=0.021), especially the RBBB (20% VS 7.4%, P=0.003). Ventricular fibrillation (VF) was observed in 5.2% and 1.2% and ventricular tachycardia in 26% and 12.2% respectively. In 27% of patients with RVMI it was necessary to implant a pacemaker as compared to 10% in control group. Mortality was higher in the patients with inferior infarction extended to the RV (15.3% vs 3.5%., P=0.0001). There was not a meaningful difference in incidence of LBBB between group 1 and 2 (3.1% vs 2.9% P=0.9). Patients with inferior MI who also have RV myocardial involvement are at increased risk of death and arrhythmias. (author)

Interaction in the large energetics companies in the Republic of Macedonia (Part 3)

International Nuclear Information System (INIS)

Janevski, Risto

2000-01-01

After the disintegration of former power energetic system of Yugoslavia 1991, the Republic of Macedonia has faced enormous problems in the energetic field. It was necessary to realize all options in order to secure enough electric power for normal economic capacities function. In that course a direct involvement of five large companies, which represent very significant energetic subjects, will largely determine the future energetic conditions and circumstances in our country. These are the following companies: P.E. Electric Power Co. of Macedonia; Heat Power Co.; HEK Jugohrom; Fenimak. In this paper the energetic system of the OKTA Crude Oil Refinery from 1991-1998 is analyzed, as well as its characteristics and plans for the future development

Effect of acute alloxan diabetes on ischemic and reperfusion arrhythmias in rats with different activity of nitric oxide system.

Science.gov (United States)

Belkina, L M; Terekhina, O L; Smirnova, E A; Usacheva, M A; Kruglov, S V; Saltykova, V A

2011-01-01

Similar degree of glycemia (28-31 mmol/liter) and similar mortality (37-42%) were revealed in August rats exhibiting enhanced activity of NO system and in Wistar rats 3 weeks after alloxan treatment. Under conditions of myocardial ischemia caused by 10-min coronary artery ligation, the intensity of arrhythmias did not differ from the control in Wistar rats with diabetes mellitus and increased in August rats. Under conditions of reperfusion, diabetes produced an antiarrhythmic effect in Wistar rats and did not affect arrhythmia in August rats. Plasma concentrations of nitrates and nitrites in Wistar and August rats increased by 82 and 143%, respectively, compared to the control. The level of hemoxygenase-1 (hsp32) in the myocardium remained unchanged in Wistar rats and decreased by 26% in August rats. Thus, the absence of antiarrhythmic effect of acute diabetes in August rats is probably related to elevated NO content and reduced antioxidant activity.

Streaming reversal of energetic particles in the magnetetail during a substorm

International Nuclear Information System (INIS)

Lui, A.T.Y.; Williams, D.J.; Eastman, T.E.; Frank, L.A.; Akasofu, S.

1984-01-01

Reversal from tailward streaming to earthward streaming of energetic ions at 0.29--0.50 MeV during a substorm on February 3, 1978, is studied with measurements of energetic particles, plasma, and magnetic field from that IMP 8 spacecraft near the dusk flank of the magnetotail. Four new features emerge when high time resolution data are examined in detail. The times of reversal from tailward to earthward streaming of energetic ions and from tailward to earthward plasma flow do not coincide. Second, the velocity distribution in the tailward flowing plasma has a cresent shape, whereas the velocity distribution in the earthward flowing plasma has a crescent shape, whereas the velocity distribution in the earthward flowing plasma resembles a convecting Maxwellian. Third, tailward streaming of energetic ions is sometime detected in northward magnetic field regions and conversely, earthward streaming in southward field environments. Fourth, energetic ions scattering earthward are occasionally present in conjunction with a strong tailward streaming population in the same energy range. These new features suggest that the streaming reversal of energetic ions and the plasma flow reversal in this event are due to the spacecraft traversing different plasma regions during the substorm-associated configurational change of the plasma sheet and the magnetotail and is unrelated to the motion of an acceleration region such as an X type neutral line moving past the spacecraft

Energetics, Biomechanics, and Performance in Masters' Swimmers: A Systematic Review.

Science.gov (United States)

Ferreira, Maria I; Barbosa, Tiago M; Costa, Mário J; Neiva, Henrique P; Marinho, Daniel A

2016-07-01

Ferreira, MI, Barbosa, TM, Costa, MJ, Neiva, HP, and Marinho, DA. Energetics, biomechanics, and performance in masters' swimmers: a systematic review. J Strength Cond Res 30(7): 2069-2081, 2016-This study aimed to summarize evidence on masters' swimmers energetics, biomechanics, and performance gathered in selected studies. An expanded search was conducted on 6 databases, conference proceedings, and department files. Fifteen studies were selected for further analysis. A qualitative evaluation of the studies based on the Quality Index (QI) was performed by 2 independent reviewers. The studies were thereafter classified into 3 domains according to the reported data: performance (10 studies), energetics (4 studies), and biomechanics (6 studies). The selected 15 articles included in this review presented low QI scores (mean score, 10.47 points). The biomechanics domain obtained higher QI (11.5 points), followed by energetics and performance (10.6 and 9.9 points, respectively). Stroke frequency (SF) and stroke length (SL) were both influenced by aging, although SF is more affected than SL. Propelling efficiency (ηp) decreased with age. Swimming performance declined with age. The performance declines with age having male swimmers deliver better performances than female counterparts, although this difference tends to be narrow in long-distance events. One single longitudinal study is found in the literature reporting the changes in performance over time. The remaining studies are cross-sectional designs focusing on the energetics and biomechanics. Overall, biomechanics parameters, such as SF, SL, and ηp, tend to decrease with age. This review shows the lack of a solid body of knowledge (reflected in the amount and quality of the articles published) on the changes in biomechanics, energetics, and performance of master swimmers over time. The training programs for this age-group should aim to preserve the energetics as much as possible and, concurrently, improve the

Atypical energetic particle events observed prior energetic particle enhancements associated with corotating interaction regions

Science.gov (United States)

Khabarova, Olga; Malandraki, Olga; Zank, Gary; Jackson, Bernard; Bisi, Mario; Desai, Mihir; Li, Gang; le Roux, Jakobus; Yu, Hsiu-Shan

2017-04-01

Recent studies of mechanisms of particle acceleration in the heliosphere have revealed the importance of the comprehensive analysis of stream-stream interactions as well as the heliospheric current sheet (HCS) - stream interactions that often occur in the solar wind, producing huge magnetic cavities bounded by strong current sheets. Such cavities are usually filled with small-scale magnetic islands that trap and re-accelerate energetic particles (Zank et al. ApJ, 2014, 2015; le Roux et al. ApJ, 2015, 2016; Khabarova et al. ApJ, 2015, 2016). Crossings of these regions are associated with unusual variations in the energetic particle flux up to several MeV/nuc near the Earth's orbit. These energetic particle flux enhancements called "atypical energetic particle events" (AEPEs) are not associated with standard mechanisms of particle acceleration. The analysis of multi-spacecraft measurements of energetic particle flux, plasma and the interplanetary magnetic field shows that AEPEs have a local origin as they are observed by different spacecraft with a time delay corresponding to the solar wind propagation from one spacecraft to another, which is a signature of local particle acceleration in the region embedded in expanding and rotating background solar wind. AEPEs are often observed before the arrival of corotating interaction regions (CIRs) or stream interaction regions (SIRs) to the Earth's orbit. When fast solar wind streams catch up with slow solar wind, SIRs of compressed heated plasma or more regular CIRs are created at the leading edge of the high-speed stream. Since coronal holes are often long-lived structures, the same CIR re-appears often for several consecutive solar rotations. At low heliographic latitudes, such CIRs are typically bounded by forward and reverse waves on their leading and trailing edges, respectively, that steepen into shocks at heliocentric distances beyond 1 AU. Energetic ion increases have been frequently observed in association with CIR

Radiational and energetic characteristics of diatomic molecules (data base)

International Nuclear Information System (INIS)

Kuznetsova, L.A.; Pazyuk, E.A.; Stolyarov, A.V.

1993-01-01

Data base on radiational and energetic characteristics of diatomic molecules was created. The base consists of two parts: reference system and recommended data system. The reference system contains the information about studies of radiational and energetic parameters of more than 1500 electronic states and 1700 electron transfers for ∼ 350 diatomic molecules and their ions. The base bibliography includes ∼ 3000 publications. 11 refs., 1 figs

Arrhythmia-free survival and pulmonary vein reconnection patterns after second-generation cryoballoon and contact-force radiofrequency pulmonary vein isolation.

Science.gov (United States)

Buist, Thomas J; Adiyaman, Ahmet; Smit, Jaap Jan J; Ramdat Misier, Anand R; Elvan, Arif

2018-06-01

The aim of this study was to compare second-generation cryoballoon and contact-force radiofrequency point-by-point pulmonary vein isolation (PVI) in atrial fibrillation (AF) patients with regard to pulmonary vein reconnection and arrhythmia-free survival. Altogether, 269 consecutive patients with drug-refractory AF undergoing PVI were included and randomly allocated to second-generation cryoballoon or contact-force point-by-point radiofrequency ablation. Median follow-up duration was 389 days (interquartile range 219-599). Mean age was 59 years (71% male); 136 patients underwent cryoballoon and 133 patients underwent radiofrequency ablation. Acute electrical PVI was 100% for both techniques. Procedure duration was significantly shorter in cryoballoon vs radiofrequency (166.5 vs 184.13 min P = 0.016). Complication rates were similar (6.0 vs 6.7%, P = 1.00). Single procedure freedom of atrial arrhythmias was significantly higher in cryoballoon as compared to radiofrequency (75.2 vs 57.4%, P = 0.013). In multivariate analysis, persistent AF, AF duration, and cryoballoon ablation were associated with freedom of atrial tachyarrhythmias. The number of repeat ablation procedures was significantly lower in the cryoballoon compared to radiofrequency (15.0 vs 24.3%, P = 0.045). At repeat ablation, pulmonary vein reconnection rate was significantly lower after cryoballoon as compared to radiofrequency ablation (36.8 vs 58.1%, P = 0.003). Improved arrhythmia-free survival and more durable pulmonary vein isolation is seen after PVI using second-generation cryoballoon as compared to contact-force radiofrequency, in patients with drug-refractory paroxysmal AF. Complication rates for both ablation techniques are low.

Energetic cost of communication.

Science.gov (United States)

Stoddard, Philip K; Salazar, Vielka L

2011-01-15

Communication signals may be energetically expensive or inexpensive to produce, depending on the function of the signal and the competitive nature of the communication system. Males of sexually selected species may produce high-energy advertisement signals, both to enhance detectability and to signal their size and body condition. Accordingly, the proportion of the energy budget allocated to signal production ranges from almost nothing for many signals to somewhere in excess of 50% for acoustic signals in short-lived sexually selected species. Recent data from gymnotiform electric fish reveal mechanisms that regulate energy allocated to sexual advertisement signals through dynamical remodeling of the excitable membranes in the electric organ. Further, males of the short-lived sexually selected species, Brachyhypopomus gauderio, trade off among different metabolic compartments, allocating energy to signal production while reducing energy used in other metabolic functions. Female B. gauderio, by contrast, do not trade off energy between signaling and other functions. To fuel energetically expensive signal production, we expect a continuum of strategies to be adopted by animals of different life history strategies. Future studies should explore the relation between life history and energy allocation trade-offs.

Stabilized super-thermite colloids: A new generation of advanced highly energetic materials

Science.gov (United States)

Elbasuney, Sherif; Gaber Zaky, M.; Radwan, Mostafa; Mostafa, Sherif F.

2017-10-01

One of the great impetus of nanotechnology on energetic materials is the achievement of nanothermites (metal-oxide/metal) which are characterized by massive heat output. Yet, full exploitation of super-thermites in highly energetic systems has not been achieved. This manuscript reports on the sustainable fabrication of colloidal Fe2O3 and CuO nanoparticles for thermite applications. TEM micrographs demonstrated mono-dispersed Fe2O3 and CuO with an average particle size of 3 and 15 nm respectively. XRD diffractograms demonstrated highly crystalline materials. SEM micrographs demonstrated a great tendency of the developed oxides to aggregate over drying process. The effective integration and dispersion of mono-dispersed colloidal thermite particles into energetic systems are vital for enhanced performance. Aluminum is of interest as highly energetic metal fuel. In this paper, synthesized Fe2O3 and CuO nanoparticles were re-dispersed in isopropyl alcohol (IPA) with aluminum nanoparticles using ultrasonic prope homogenizer. The colloidal thermite peraticles can be intgegrated into highly energetic system for subsequent nanocomposite development. Thanks to stabilization of colloidal CuO nanoparticles in IPA which could offer intimate mixing between oxidizer and metal fuel. The stabilization mechanism of CuO in IPA was correlated to steric stabilization with solvent molecules. This approach eliminated nanoparticle drying and the re-dispersion of dry aggregates into energetic materials. This manuscript shaded the light on the real development of colloidal thermite mixtures and their integration into highly energetic systems.

An international multicenter study comparing arrhythmia prevalence between the intracardiac lateral tunnel and the extracardiac conduit type of Fontan operations.

Science.gov (United States)

Balaji, Seshadri; Daga, Ankana; Bradley, David J; Etheridge, Susan P; Law, Ian H; Batra, Anjan S; Sanatani, Shubayan; Singh, Anoop K; Gajewski, Kelly K; Tsao, Sabrina; Singh, Harinder R; Tisma-Dupanovic, Svjetlana; Tateno, Shigeru; Takamuro, Motoki; Nakajima, Hiromichi; Roos-Hesselink, Jolien W; Shah, Maully

2014-08-01

The study objective was to determine whether the extracardiac conduit Fontan confers an arrhythmia advantage over the intracardiac lateral tunnel Fontan. This multicenter study of 1271 patients compared bradyarrhythmia (defined as need for pacing) and tachyarrhythmia (defined as needing antiarrhythmic therapy) between 602 patients undergoing the intracardiac Fontan and 669 patients undergoing the extracardiac Fontan. The median age at the time of the Fontan procedure was 2.1 years (interquartile range, 1.6-3.2 years) for the intracardiac group and 3.0 years (interquartile range, 2.4-3.9) for the extracardiac group (P 30 days) bradyarrhythmia occurred in 105 patients (18%) in the intracardiac group and 63 patients (9%) in the extracardiac group (P 30 days) tachyarrhythmia occurred in 58 patients (10%) in the intracardiac group and 23 patients (3%) in the extracardiac group (P factoring time since surgery, more patients in the extracardiac group had early bradycardia (odds ratio, 2.9; 95% confidence interval, 1.8-4.6), with no difference in early tachycardia, late bradycardia, or late tachycardia. Overall arrhythmia burden is similar between the 2 groups, but the extracardiac Fontan group had a higher incidence of early bradyarrhythmias. There was no difference in the incidence of late tachyarrhythmias over time between the 2 operations. Therefore, the type of Fontan performed should be based on factors other than an anticipated reduction in arrhythmia burden from the extracardiac conduit. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Effects of Statin on Arrhythmia and Heart Rate Variability in Healthy Persons With 48-Hour Sleep Deprivation.

Science.gov (United States)

Chen, Wei Ren; Liu, Hong Bin; Sha, Yuan; Shi, Yang; Wang, Hao; Yin, Da Wei; Chen, Yun Dai; Shi, Xiang Min

2016-10-31

It has been reported that sleep deprivation is associated with cardiac autonomic disorder, inflammation, and oxidative stress. Statins have significant cardiovascular protective effects in patients with cardiovascular disease. This study aimed to investigate the protective effect of statins on arrhythmia and heart rate variability in young healthy persons after 48-hour sleep deprivation. This study enrolled 72 young healthy participants aged 26.5±3.5 years. All participants received 48-hour continuous ambulatory electrocardiogram monitoring. Arrhythmia, time, and frequency domain parameters were analyzed for all participants. The primary end point, low/high frequency ratio, was significantly lower in the statin group than in the control group (2.48±1.12 versus 3.02±1.23, Psleep deprivation, low frequency-the frequency of premature atrial complexes and premature ventricular complexes-was significantly decreased in the statin group compared with the control group (Psleep deprivation in the statin group compared with the control group (Psleep deprivation. This finding should be confirmed by larger scale trials. URL: http://www.clinicaltrials.gov. Unique identifier: NCT02496962. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Heterogeneity in 2-deoxy-D-glucose-induced modifications in energetics and radiation responses of human tumor cell lines

International Nuclear Information System (INIS)

Dwarkanath, Bilikere S.; Zolzer, Frido; Chandana, Sudhir; Bauch, Thomas; Adhikari, Jawahar S.; Muller, Wolfgang U.; Streffer, Christian; Jain, Viney

2001-01-01

the squamous carcinoma 4451, whereas an increase was noted in the glioma cell line BMG-1. 2-DG significantly reduced the initial rates of DNA repair in all cells, resulting in an excess residual damage after 2 h of repair in BMG-1, U-87, and 4451 cell lines, whereas no significant differences could be observed in the other cell lines. Recovery from potentially lethal damage was also significantly inhibited in BMG-1 cells. 2-DG increased the radiation-induced micronuclei formation in the melanoma line (MeWo) by nearly 60%, while a moderate (25-40%) increase was observed in the glioma cell lines (BMG-1 and U-87). Presence of 2-DG during liquid holding (4 h) enhanced the radiation-induced cell death by nearly 40% in both the glioma cell lines, while significant effects were not observed in others. Conclusions: The modifications in energetics and radiation responses by 2-DG vary considerably among different human tumor cell lines, and the relationships between energy metabolism and various radiobiologic parameters are complex in nature. The 2-DG-induced modification of radiation response does not strictly correlate with changes in the levels of ATP. However, a significant enhancement of the radiation damage by 2-DG was observed in cells with high rates of glucose usage and glycolysis, which appear to be the two most important factors determining the tumor response to the combined treatment of 2-DG + radiation therapy

Molecular and Material Approaches to Overcome Kinetic and Energetic Constraints in Dye-Sensitized Solar Cells

Energy Technology Data Exchange (ETDEWEB)

Hamann, Thomas [Michigan State Univ., East Lansing, MI (United States)

2016-08-14

Dye-sensitized solar cells (DSSCs) have attracted a lot of interest as they proffer the possibility of extremely inexpensive and efficient solar energy conversion. The excellent performance of the most efficient DSSCs relies on two main features: 1) a high surface area nanoparticle semiconductor photoanode to allow for excellent light absorption with moderate extinction molecular dyes and 2) slow recombination rates from the photoanode to I₃^- allowing good charge collection. The I₃^-/I^- couple, however, has some disadvantages, notably the redox potential limits the maximum open-circuit voltage, and the dye regeneration requires a large driving force which constrains the light harvesting ability. Thus, the design features that allow DSSCs to perform as well as they do also prevent further significant improvements in performance. As a consequence, the most efficient device configuration, and the maximum efficiency, has remained essentially unchanged over the last 16 years. Significant gains in performance are possible; however it will likely require a substantial paradigm shift. The general goal of this project is to understand the fundamental role of dye-sensitized solar cell, DSSC, components (sensitizer, redox shuttle, and photoanode) involved in key processes in order to overcome the kinetic and energetic constraints of current generation DSSCs. For example, the key to achieving high energy conversion efficiency DSSCs is the realization of a redox shuttle which fulfills the dual requirements of 1) efficient dye regeneration with a minimal driving force and 2) efficient charge collection. In current generation DSSCs, however, only one or the other of these requirements is met. We are currently primarily interested in understanding the physical underpinnings of the regeneration and recombination reactions. Our approach is to systematically vary the components involved in reactions and interrogate them with a

Ionizing radiation - one of the most important link of the energetic chain in biological cell

Energy Technology Data Exchange (ETDEWEB)

Goraczko, W. [Technical Univ. Poznan, Radio- and Photochemistry Dept., Poznan (Poland)

1999-09-01

High (large) and low (small) doses of ionizing radiation consistently induce opposite physiologic effects in biological systems. The effects of low doses cannot be inferred by interpolation between the result from groups exposed to high doses and controls irradiated only by Natural Background Radiation. Stimulation ('bio-positive') effects by low-level doses of ionizing radiation are called radiation hormesis. It is still controversial idea, however it was found that some biological objects (yeast, seeds, animals) after gamma irradiation by low-level doses (10-50 times more NBR) can increase their development. The result of present researches demonstrate that the excitation of living system by gamma quanta (high energy) initiates prolonged secondary emission that influences biota and activates many important processes in biological systems. According to the excitation theory of bio-molecules the author suggests that gamma irradiation in low-level doses excites such molecules as DNA and proteins, and this being followed by a long-termed secondary coherent radiation. The spectral analysis of this secondary emission confirmed the contribution of the UV component to the total emission. The data obtaining by using SPC method (single photon counting) make possible a partial understanding of the radiation hormesis phenomenon and suggest closer relationship to UV emission from biological systems during mitotic processes. The experiments with humic acid (high doses) and glycine (low doses) confirm the author hypothesis that gamma-irradiated organic compounds are capable to emit secondary radiation. This secondary radiation probably plays very significant role in the intercellular communication inside the living systems. In conclusion the author proposed de-excitation processes in bio-molecules as a common denominator of UV and ionizing radiation interacting with living cells. Finally he refers to the Cerenkov radiation which is created inside the biological cells

Ionizing radiation - one of the most important link of the energetic chain in biological cell

International Nuclear Information System (INIS)

Goraczko, W.

1999-01-01

High (large) and low (small) doses of ionizing radiation consistently induce opposite physiologic effects in biological systems. The effects of low doses cannot be inferred by interpolation between the result from groups exposed to high doses and controls irradiated only by Natural Background Radiation. Stimulation ('bio-positive') effects by low-level doses of ionizing radiation are called radiation hormesis. It is still controversial idea, however it was found that some biological objects (yeast, seeds, animals) after gamma irradiation by low-level doses (10-50 times more NBR) can increase their development. The result of present researches demonstrate that the excitation of living system by gamma quanta (high energy) initiates prolonged secondary emission that influences biota and activates many important processes in biological systems. According to the excitation theory of bio-molecules the author suggests that gamma irradiation in low-level doses excites such molecules as DNA and proteins, and this being followed by a long-termed secondary coherent radiation. The spectral analysis of this secondary emission confirmed the contribution of the UV component to the total emission. The data obtaining by using SPC method (single photon counting) make possible a partial understanding of the radiation hormesis phenomenon and suggest closer relationship to UV emission from biological systems during mitotic processes. The experiments with humic acid (high doses) and glycine (low doses) confirm the author hypothesis that gamma-irradiated organic compounds are capable to emit secondary radiation. This secondary radiation probably plays very significant role in the intercellular communication inside the living systems. In conclusion the author proposed de-excitation processes in bio-molecules as a common denominator of UV and ionizing radiation interacting with living cells. Finally he refers to the Cerenkov radiation which is created inside the biological cells. Because

Calculation of the energetics of chemical reactions

Energy Technology Data Exchange (ETDEWEB)

Dunning, T.H. Jr.; Harding, L.B.; Shepard, R.L.; Harrison, R.J.

1988-01-01

To calculate the energetics of chemical reactions we must solve the electronic Schroedinger equation for the molecular conformations of importance for the reactive encounter. Substantial changes occur in the electronic structure of a molecular system as the reaction progresses from reactants through the transition state to products. To describe these changes, our approach includes the following three elements: the use of multiconfiguration self-consistent field wave functions to provide a consistent zero-order description of the electronic structure of the reactants, transition state, and products; the use of configuration interaction techniques to describe electron correlation effects needed to provide quantitative predictions of the reaction energetics; and the use of large, optimized basis sets to provide the flexibility needed to describe the variations in the electronic distributions. With this approach we are able to study reactions involving as many as 5--6 atoms with errors of just a few kcal/mol in the predicted reaction energetics. Predictions to chemical accuracy, i.e., to 1 kcal/mol or less, are not yet feasible, although continuing improvements in both the theoretical methodology and computer technology suggest that this will soon be possible, at least for reactions involving small polyatomic species. 4 figs.

Energetic constraints, size gradients, and size limits in benthic marine invertebrates.

Science.gov (United States)

Sebens, Kenneth P

2002-08-01

Populations of marine benthic organisms occupy habitats with a range of physical and biological characteristics. In the intertidal zone, energetic costs increase with temperature and aerial exposure, and prey intake increases with immersion time, generating size gradients with small individuals often found at upper limits of distribution. Wave action can have similar effects, limiting feeding time or success, although certain species benefit from wave dislodgment of their prey; this also results in gradients of size and morphology. The difference between energy intake and metabolic (and/or behavioral) costs can be used to determine an energetic optimal size for individuals in such populations. Comparisons of the energetic optimal size to the maximum predicted size based on mechanical constraints, and the ensuing mortality schedule, provides a mechanism to study and explain organism size gradients in intertidal and subtidal habitats. For species where the energetic optimal size is well below the maximum size that could persist under a certain set of wave/flow conditions, it is probable that energetic constraints dominate. When the opposite is true, populations of small individuals can dominate habitats with strong dislodgment or damage probability. When the maximum size of individuals is far below either energetic optima or mechanical limits, other sources of mortality (e.g., predation) may favor energy allocation to early reproduction rather than to continued growth. Predictions based on optimal size models have been tested for a variety of intertidal and subtidal invertebrates including sea anemones, corals, and octocorals. This paper provides a review of the optimal size concept, and employs a combination of the optimal energetic size model and life history modeling approach to explore energy allocation to growth or reproduction as the optimal size is approached.

Divergent effects of adrenaline in human induced pluripotent stem cell-derived cardiomyocytes obtained from hypertrophic cardiomyopathy

Directory of Open Access Journals (Sweden)

Chandra Prajapati

2018-02-01

Full Text Available Hypertrophic cardiomyopathy (HCM is a common inherited cardiac disease that affects the heart muscle with diverse clinical outcomes. HCM can cause sudden cardiac death (SCD during or immediately after mild to rigorous physical activity in young patients. However, the mechanism causing SCD as a result of exercise remains unknown, but exercise-induced ventricular arrhythmias are thought to be responsible for this fatal consequence. To understand the disease mechanism behind HCM in a better way, we generated patient-specific induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs from HCM patients carrying either the MYBPC3-Gln1061X or TPM1-Asp175Asn mutation. We extensively investigated the effects of low to high concentrations of adrenaline on action potential characteristics, and the occurrence of arrhythmias in the presence of various concentrations of adrenaline and in wash-out condition. We classified and quantified different types of arrhythmias observed in hiPSC-CMs, and found that the occurrence of arrhythmias was dependent on concentrations of adrenaline and positions of mutations in genes causing HCM. In addition, we observed ventricular tachycardia types of arrhythmias in hiPSC-CMs carrying the TPM1-Asp175Asn mutation. We additionally examined the antiarrhythmic potency of bisoprolol in HCM-specific hiPSC-CMs. However, bisoprolol could not reduce the occurrence of arrhythmias during administration or during the wash-out condition of adrenaline in HCM-specific hiPSC-CMs. Our study demonstrates hiPSC-CMs as a promising tool for studying HCM. The experimental design used in this study could be suitable and beneficial for studying other components and drugs related to cardiac disease in general.

Reactive Energetic Plasticizers Utilizing Cu-Free Azide-Alkyne 1,3-Dipolar Cycloaddition for In-Situ Preparation of Poly(THF-co-GAP-Based Polyurethane Energetic Binders

Directory of Open Access Journals (Sweden)

Mingyang Ma

2018-05-01

Full Text Available Reactive energetic plasticizers (REPs coupled with hydroxy-telechelic poly(glycidyl azide-co-tetrahydrofuran (PGT-based energetic polyurethane (PU binders for use in solid propellants and plastic-bonded explosives (PBXs were investigated. The generation of gem-dinitro REPs along with a terminal alkyne stemmed from a series of finely designed approaches to not only satisfy common demands as conventional energetic plasticizers, but also to prevent the migration of plasticizers. The miscibility and rheological behavior of a binary mixture of PGT/REP with various REP fractions were quantitatively determined by differential scanning calorimetry (DSC and rheometer, respectively, highlighting the promising performance of REPs in the formulation process. The kinetics on the distinct reactivity of propargyl vs. 3-butynyl species of REPs towards the azide group of the PGT prepolymer in terms of Cu-free azide-alkyne 1,3-dipolar cycloaddition (1,3-DPCA was studied by monitoring 1H nuclear magnetic resonance spectroscopy and analyzing the activation energies (Ea obtained using DSC. The thermal stability of the finally cured energetic binders with the incorporation of REPs indicated that the thermal stability of the REP/PGT-based PUs was maintained independently of the REP content. The tensile strength and modulus of the PUs increased with an increase in the REP content. In addition, the energetic performance and sensitivity of REP and REP triazole species was predicted.

Influence of Blend Morphology and Energetics on Charge Separation and Recombination Dynamics in Organic Solar Cells Incorporating a Nonfullerene Acceptor

KAUST Repository

Cha, Hyojung

2017-11-27

Nonfullerene acceptors (NFAs) in blends with highly crystalline donor polymers have been shown to yield particularly high device voltage outputs, but typically more modest quantum yields for photocurrent generation as well as often lower fill factors (FF). In this study, we employ transient optical and optoelectronic analysis to elucidate the factors determining device photocurrent and FF in blends of the highly crystalline donor polymer PffBT4T-2OD with the promising NFA FBR or the more widely studied fullerene acceptor PC71BM. Geminate recombination losses, as measured by ultrafast transient absorption spectroscopy, are observed to be significantly higher for PffBT4T-2OD:FBR blends. This is assigned to the smaller LUMO-LUMO offset of the PffBT4T-2OD:FBR blends relative to PffBT4T-2OD:PC71BM, resulting in the lower photocurrent generation efficiency obtained with FBR. Employing time delayed charge extraction measurements, these geminate recombination losses are observed to be field dependent, resulting in the lower FF observed with PffBT4T-2OD:FBR devices. These data therefore provide a detailed understanding of the impact of acceptor design, and particularly acceptor energetics, on organic solar cell performance. Our study concludes with a discussion of the implications of these results for the design of NFAs in organic solar cells.

Influence of Blend Morphology and Energetics on Charge Separation and Recombination Dynamics in Organic Solar Cells Incorporating a Nonfullerene Acceptor

KAUST Repository

Cha, Hyojung; Wheeler, Scot; Holliday, Sarah; Dimitrov, Stoichko D.; Wadsworth, Andrew; Lee, Hyun Hwi; Baran, Derya; McCulloch, Iain; Durrant, James R.

2017-01-01

Nonfullerene acceptors (NFAs) in blends with highly crystalline donor polymers have been shown to yield particularly high device voltage outputs, but typically more modest quantum yields for photocurrent generation as well as often lower fill factors (FF). In this study, we employ transient optical and optoelectronic analysis to elucidate the factors determining device photocurrent and FF in blends of the highly crystalline donor polymer PffBT4T-2OD with the promising NFA FBR or the more widely studied fullerene acceptor PC71BM. Geminate recombination losses, as measured by ultrafast transient absorption spectroscopy, are observed to be significantly higher for PffBT4T-2OD:FBR blends. This is assigned to the smaller LUMO-LUMO offset of the PffBT4T-2OD:FBR blends relative to PffBT4T-2OD:PC71BM, resulting in the lower photocurrent generation efficiency obtained with FBR. Employing time delayed charge extraction measurements, these geminate recombination losses are observed to be field dependent, resulting in the lower FF observed with PffBT4T-2OD:FBR devices. These data therefore provide a detailed understanding of the impact of acceptor design, and particularly acceptor energetics, on organic solar cell performance. Our study concludes with a discussion of the implications of these results for the design of NFAs in organic solar cells.

Organization of the national energetic institutions

International Nuclear Information System (INIS)

Waltenberg, D.A.M.

1983-01-01

This text broaches, in a critical pourt of view, the organization of national energetic institutions, the need of a law revision, the problem of the rising of tariff and shows the decisions of GC01 [pt

Human Cell Line Activation Test of the Novel Energetics Methyl Trinitropryrazol (MTNP) and 1,3-Dimethylhexahydropyrimidine (DHP)

Science.gov (United States)

2017-11-01

costs, conserve physical resources, and sustain the health of those potentially exposed. The U.S. Army RDECOM, ETAP has been dedicated to finding...trinitropryrazol (MTNP) and 1,3-dimethylhexahydropyrimidine (DHP) Prepared by: Emily Reinke, Ph.D. Health Effects Division Toxicology...the Novel Energetics methyl trinitropyrazol (MTNP) and 1,3-dimethylhexahydropyrimidine (DHP) Emily N. Reinke, Ph.D. Army Public Health Center

Pulsations of Energetic Electron Pulsations In Association With Substorm Onset

Science.gov (United States)

Åsnes, A.; Stadsnes, J.; Bjordal, J.; Østgaard, N.; Haaland, S.; Rosenberg, T. J.; Detrick, D. L.

The Polar Ionospheric X-ray Imaging Experiment (PIXIE) is giving detailed images of the energetic electron precipitation when the POLAR satellite is near perigee over the Antarctica. In this area the PIXIE images have a spatial resolution of the order of 100 km, and a temporal resolution of 10 s can be obtained. In this paper we present the results of a study focusing on the onset and expansion of a substorm occuring on July 24, 1998. In this event we observe strong modulations of the energetic electron precipitation with period around 1 minute following substorm onset. The pulsations were restricted to a narrow magnetic local time sector in the pre-midnight region, about 0.5 hours wide, and showed movement towards higher latitudes and earlier lo- cal times. The event will be discussed in context of measurements from ground sta- tions and satellites in geosynchronous orbit. Precipitation of energetic electrons will be compared with VLF/ELF ground measurements. Features in the energetic elec- tron precipitation will be mapped to the magnetospheric equatorial plane by field line tracing.

ENERGETIC EXTREMES IN REEF FISH OCCUPYING HARSH HABITATS

DEFF Research Database (Denmark)

Steffensen, John Fleng

2009-01-01

document how relatively small changes in fin morphology has afforded some coral reef fish taxa with exceptional locomotor performance and energetic efficiency, and how this key attribute may have played a key role in the evolution and ecology of several diverse Indo-Pacific reef fish families. Using......-finned counterparts. We discuss how such differences in locomotor efficiency are pivotal to the habitat-use of these fishes, and how eco-energetic models may be used to provide new insights into spatial variations in fish demography and ecology among coral reef habitat zones....

Energetic, spectral, and temporal characteristics of a two-wave CO/sub 2/ laser

Energy Technology Data Exchange (ETDEWEB)

Bertel' , I.M.; Petukhov, V.O.; Prokopov, A.P.; Tochitskii, S.Ya.; Churakov, V.V.

1987-09-01

This work studies the energetic and temporal parameters of a pulsed two-wave TEA CO/sub 2/ laser's radiation and the means for controlling these parameters. Obtaining the two-wave generation regime in CO/sub 2/ lasers uses, as is known, spatial splitting of the radiation, different variants of operating diffraction gratings, and placing a cell with selectively absorbing gas in the resonator. To realize the simultaneous two-wave generation regime in the present work, a double-resonant scheme is used with mutually orthogonal polarizers to spatially separate the radiation.

Energetic ion driven Alfven eigenmodes in Large Helical Device plasmas with three-dimensional magnetic structure and their impact on energetic ion transport

International Nuclear Information System (INIS)

Toi, K; Yamamoto, S; Nakajima, N; Ohdachi, S; Sakakibara, S; Osakabe, M; Murakami, S; Watanabe, K Y; Goto, M; Kawahata, K; Kolesnichenko, Ya I; Masuzaki, S; Morita, S; Narihara, K; Narushima, Y; Takeiri, Y; Tanaka, K; Tokuzawa, T; Yamada, H; Yamada, I; Yamazaki, K

2004-01-01

In the Large Helical Device (LHD), energetic ion driven Alfven eigenmodes (AEs) and their impact on energetic ion transport have been studied. The magnetic configuration of the LHD is three-dimensional and has negative magnetic shear over a whole plasma radius in the low beta regime. These features introduce the characteristic structures of the shear Alfven spectrum. In particular, a core-localized type of toroidicity-induced AE (TAE) is most likely because the TAE gap frequency rapidly increases towards the plasma edge. Moreover, helicity-induced AEs (HAEs) can be generated through a toroidal mode coupling as well as poloidal one in the three-dimensional configuration. The following experimental results have been obtained in LHD plasmas heated by tangential neutral beam injection: (1) observation of core-localized TAEs having odd as well as even parity, (2) eigenmode transition of the core-localized TAE to global AEs (GAEs), which phenomenon is very similar to that in a reversed shear tokamak, (3) observation of HAEs of which the frequency is about eight times higher than the TAE gap frequency, (4) enhanced radial transport/loss of energetic ions caused by bursting TAEs in a relatively high beta regime, and (5) seed formation of internal transport barriers induced by TAE-induced energetic ion transport. These results will be important and interesting information for AE physics in toroidal plasmas

Energetic Electron Acceleration and Injection During Dipolarization Events in Mercury's Magnetotail

Science.gov (United States)

Dewey, Ryan M.; Slavin, James A.; Raines, Jim M.; Baker, Daniel N.; Lawrence, David J.

2017-12-01

Energetic particle bursts associated with dipolarization events within Mercury's magnetosphere were first observed by Mariner 10. The events appear analogous to particle injections accompanying dipolarization events at Earth. The Energetic Particle Spectrometer (3 s resolution) aboard MESSENGER determined the particle bursts are composed entirely of electrons with energies ≳ 300 keV. Here we use the Gamma-Ray Spectrometer high-time-resolution (10 ms) energetic electron measurements to examine the relationship between energetic electron injections and magnetic field dipolarization in Mercury's magnetotail. Between March 2013 and April 2015, we identify 2,976 electron burst events within Mercury's magnetotail, 538 of which are closely associated with dipolarization events. These dipolarizations are detected on the basis of their rapid ( 2 s) increase in the northward component of the tail magnetic field (ΔBz 30 nT), which typically persists for 10 s. Similar to those at Earth, we find that these dipolarizations appear to be low-entropy, depleted flux tubes convecting planetward following the collapse of the inner magnetotail. We find that electrons experience brief, yet intense, betatron and Fermi acceleration during these dipolarizations, reaching energies 130 keV and contributing to nightside precipitation. Thermal protons experience only modest betatron acceleration. While only 25% of energetic electron events in Mercury's magnetotail are directly associated with dipolarization, the remaining events are consistent with the Near-Mercury Neutral Line model of magnetotail injection and eastward drift about Mercury, finding that electrons may participate in Shabansky-like closed drifts about the planet. Magnetotail dipolarization may be the dominant source of energetic electron acceleration in Mercury's magnetosphere.

Magneto-Hydrodynamic Activity and Energetic Particles - Application to Beta Alfven Eigenmodes

International Nuclear Information System (INIS)

Nguyen, Ch.

2009-12-01

The goal of magnetic fusion research is to extract the power released by fusion reactions and carried by the product of these reactions, liberated at energies of the order of a few MeV. The feasibility of fusion energy production relies on our ability to confine these energetic particles, while keeping the thermonuclear plasma in safe operating conditions. For that purpose, it is necessary to understand and find ways to control the interaction between energetic particles and the thermonuclear plasma. Reaching these two goals is the general motivation for this work. More specifically, our focus is on one type of instability, the Beta Alfven Eigenmode (BAE), which can be driven by energetic particles and impact on the confinement of both energetic and thermal particles. In this work, we study the characteristics of BAEs analytically and derive its dispersion relation and structure. Next, we analyze the linear stability of the mode in the presence of energetic particles. First, a purely linear description is used, which makes possible to get an analytical linear criterion for BAE destabilization in the presence of energetic particles. This criterion is compared with experiments conducted in the Tore-Supra tokamak. Secondly, because the linear analysis reveals some features of the BAE stability which are subject to a strong nonlinear modification, the question is raised of the possibility of a sub-critical activity of the mode. We propose a simple scenario which makes possible the existence of meta-stable modes, verified analytically and numerically. Such a scenario is found to be relevant to the physics and scales characterizing BAEs. (author)

Sunward-propagating Solar Energetic Electrons inside Multiple Interplanetary Flux Ropes

Energy Technology Data Exchange (ETDEWEB)

Gómez-Herrero, Raúl; Hidalgo, Miguel A.; Carcaboso, Fernando; Blanco, Juan J. [Dpto. de Física y Matemáticas, Universidad de Alcalá, E-28871 Alcalá de Henares, Madrid (Spain); Dresing, Nina; Klassen, Andreas; Heber, Bernd [Institut für Experimentelle und Angewandte Physik, University of Kiel, D-24118, Kiel (Germany); Temmer, Manuela; Veronig, Astrid [Institute of Physics/Kanzelhöhe Observatory, University of Graz, A-8010 Graz (Austria); Bučík, Radoslav [Institut für Astrophysik, Georg-August-Universität Göttingen, D-37077, Göttingen (Germany); Lario, David, E-mail: raul.gomezh@uah.es [The Johns Hopkins University, Applied Physics Laboratory, Laurel, MD 20723 (United States)

2017-05-10

On 2013 December 2 and 3, the SEPT and STE instruments on board STEREO-A observed two solar energetic electron events with unusual sunward-directed fluxes. Both events occurred during a time interval showing typical signatures of interplanetary coronal mass ejections (ICMEs). The electron timing and anisotropies, combined with extreme-ultraviolet solar imaging and radio wave spectral observations, are used to confirm the solar origin and the injection times of the energetic electrons. The solar source of the ICME is investigated using remote-sensing observations and a three-dimensional reconstruction technique. In situ plasma and magnetic field data combined with energetic electron observations and a flux-rope model are used to determine the ICME magnetic topology and the interplanetary electron propagation path from the Sun to 1 au. Two consecutive flux ropes crossed the STEREO-A location and each electron event occurred inside a different flux rope. In both cases, the electrons traveled from the solar source to 1 au along the longest legs of the flux ropes still connected to the Sun. During the December 2 event, energetic electrons propagated along the magnetic field, while during the December 3 event they were propagating against the field. As found by previous studies, the energetic electron propagation times are consistent with a low number of field line rotations N < 5 of the flux rope between the Sun and 1 au. The flux rope model used in this work suggests an even lower number of rotations.

Energetics of edge oxidization of graphene nanoribbons

Science.gov (United States)

Yasuma, Airi; Yamanaka, Ayaka; Okada, Susumu

2018-06-01

On the basis of the density functional theory, we studied the geometries and energetics of O atoms adsorbed on graphene edges for simulating the initial stage of the edge oxidization of graphene. Our calculations showed that oxygen atoms are preferentially adsorbed onto the graphene edges with the zigzag portion, resulting in a large adsorption energy of about 5 eV. On the other hand, the edges with armchair shape are rarely oxidized, or the oxidization causes substantial structural reconstructions, because of the stable covalent bond at the armchair edge with the triple bond nature. Furthermore, the energetics sensitively depends on the edge angles owing to the inhomogeneity of the charge density at the edge atomic sites.

Energetic particles at venus: galileo results.

Science.gov (United States)

Williams, D J; McEntire, R W; Krimigis, S M; Roelof, E C; Jaskulek, S; Tossman, B; Wilken, B; Stüdemann, W; Armstrong, T P; Fritz, T A; Lanzerotti, L J; Roederer, J G

1991-09-27

At Venus the Energetic Particles Detector (EPD) on the Galileo spacecraft measured the differential energy spectra and angular distributions of ions >22 kiloelectron volts (keV) and electrons > 15 keV in energy. The only time particles were observed by EPD was in a series of episodic events [0546 to 0638 universal time (UT)] near closest approach (0559:03 UT). Angular distributions were highly anisotropic, ordered by the magnetic field, and showed ions arriving from the hemisphere containing Venus and its bow shock. The spectra showed a power law form with intensities observed into the 120- to 280-keV range. Comparisons with model bow shock calculations show that these energetic ions are associated with the venusian foreshock-bow shock region. Shock-drift acceleration in the venusian bow shock seems the most likely process responsible for the observed ions.

Real-Time Analytics for the Healthcare Industry: Arrhythmia Detection.

Science.gov (United States)

Agneeswaran, Vijay Srinivas; Mukherjee, Joydeb; Gupta, Ashutosh; Tonpay, Pranay; Tiwari, Jayati; Agarwal, Nitin

2013-09-01

It is time for the healthcare industry to move from the era of "analyzing our health history" to the age of "managing the future of our health." In this article, we illustrate the importance of real-time analytics across the healthcare industry by providing a generic mechanism to reengineer traditional analytics expressed in the R programming language into Storm-based real-time analytics code. This is a powerful abstraction, since most data scientists use R to write the analytics and are not clear on how to make the data work in real-time and on high-velocity data. Our paper focuses on the applications necessary to a healthcare analytics scenario, specifically focusing on the importance of electrocardiogram (ECG) monitoring. A physician can use our framework to compare ECG reports by categorization and consequently detect Arrhythmia. The framework can read the ECG signals and uses a machine learning-based categorizer that runs within a Storm environment to compare different ECG signals. The paper also presents some performance studies of the framework to illustrate the throughput and accuracy trade-off in real-time analytics.

CIRCUMSOLAR ENERGETIC PARTICLE DISTRIBUTION ON 2011 NOVEMBER 3

Energy Technology Data Exchange (ETDEWEB)

Gómez-Herrero, R.; Blanco, J.J.; Rodríguez-Pacheco, J. [SRG, Universidad de Alcalá, E-28871 Alcalá de Henares (Spain); Dresing, N.; Klassen, A.; Heber, B.; Banjac, S. [IEAP, Christian-Albrechts-Universität zu Kiel, D-24118 Kiel (Germany); Lario, D. [The Johns Hopkins University, Applied Physics Laboratory, Laurel, MD 20723 (United States); Agueda, N. [Departament d' Astronomia i Meteorologia. Institut de Ciències del Cosmos. Universitat de Barcelona, E-08028 Barcelona (Spain); Malandraki, O. E., E-mail: raul.gomezh@uah.es [IAASARS, National Observatory of Athens, GR-15236 Penteli (Greece)

2015-01-20

Late on 2011 November 3, STEREO-A, STEREO-B, MESSENGER, and near-Earth spacecraft observed an energetic particle flux enhancement. Based on the analysis of in situ plasma and particle observations, their correlation with remote sensing observations, and an interplanetary transport model, we conclude that the particle increases observed at multiple locations had a common single-source active region and the energetic particles filled a very broad region around the Sun. The active region was located at the solar backside (as seen from Earth) and was the source of a large flare, a fast and wide coronal mass ejection, and an EIT wave, accompanied by type II and type III radio emission. In contrast to previous solar energetic particle events showing broad longitudinal spread, this event showed clear particle anisotropies at three widely separated observation points at 1 AU, suggesting direct particle injection close to the magnetic footpoint of each spacecraft, lasting for several hours. We discuss these observations and the possible scenarios explaining the extremely broad particle spread for this event.

Energetic stress: The reciprocal relationship between energy availability and the stress response.

Science.gov (United States)

Harrell, C S; Gillespie, C F; Neigh, G N

2016-11-01

The worldwide epidemic of metabolic syndromes and the recognized burden of mental health disorders have driven increased research into the relationship between the two. A maladaptive stress response is implicated in both mental health disorders and metabolic disorders, implicating the hypothalamic-pituitary-adrenal (HPA) axis as a key mediator of this relationship. This review explores how an altered energetic state, such as hyper- or hypoglycemia, as may be manifested in obesity or diabetes, affects the stress response and the HPA axis in particular. We propose that changes in energetic state or energetic demands can result in "energetic stress" that can, if prolonged, lead to a dysfunctional stress response. In this review, we summarize the role of the hypothalamus in modulating energy homeostasis and then briefly discuss the relationship between metabolism and stress-induced activation of the HPA axis. Next, we examine seven mechanisms whereby energetic stress interacts with neuroendocrine stress response systems, including by glucocorticoid signaling both within and beyond the HPA axis; by nutrient-induced changes in glucocorticoid signaling; by impacting the sympathetic nervous system; through changes in other neuroendocrine factors; by inducing inflammatory changes; and by altering the gut-brain axis. Recognizing these effects of energetic stress can drive novel therapies and prevention strategies for mental health disorders, including dietary intervention, probiotics, and even fecal transplant. Copyright © 2015 Elsevier Inc. All rights reserved.

Pharmacological delayed preconditioning against ischaemia-induced ventricular arrhythmias: effect of an adenosine A1-receptor agonist

OpenAIRE

Tissier, Renaud; Souktani, Rachid; Parent de Curzon, Olivier; Lellouche, Nicolas; Henry, Patrick; Giudicelli, Jean-François; Berdeaux, Alain; Ghaleh, Bijan

2001-01-01

The goal of this study was to investigate the effects of the delayed pharmacological preconditioning produced by an adenosine A1-receptor agonist (A1-DPC) against ventricular arrhythmias induced by ischaemia and reperfusion, compared to those of ischaemia-induced delayed preconditioning (I-DPC).Eighty-nine instrumented conscious rabbits underwent a 2 consecutive days protocol. On day 1, rabbits were randomly divided into four groups: ‘Control' (saline, i.v.), ‘I-DPC' (six 4-min coronary arter...

An automatic system to study sperm motility and energetics

OpenAIRE

Shi, LZ; Nascimento, JM; Chandsawangbhuwana, C; Botvinick, EL; Berns, MW

2008-01-01

An integrated robotic laser and microscope system has been developed to automatically analyze individual sperm motility and energetics. The custom-designed optical system directs near-infrared laser light into an inverted microscope to create a single-point 3-D gradient laser trap at the focal spot of the microscope objective. A two-level computer structure is described that quantifies the sperm motility (in terms of swimming speed and swimming force) and energetics (measuring mid-piece membr...

The source of multi spectral energy of solar energetic electron

Energy Technology Data Exchange (ETDEWEB)

Herdiwijaya, Dhani [Astronomy Division and Bosscha Observatory, Faculty Mathematics and Natural Sciences, Intitute Technology of Bandung, Ganesha 10, Bandung, Indonesia 40132 dhani@as.itb.ac.id (Indonesia)

2015-04-16

We study the solar energetic electron distribution obtained from ACE and GOES satellites which have different altitudes and electron spectral energy during the year 1997 to 2011. The electron spectral energies were 0.038–0.315 MeV from EPAM instrument onboard ACE satellite and >2 MeV from GOES satellite. We found that the low electron energy has no correlation with high energy. In spite of we have corrected to the altitude differences. It implied that they originated from time dependent events with different sources and physical processes at the solar atmosphere. The sources of multi spectral energetic electron were related to flare and CME phenomena. However, we also found that high energetic electron comes from coronal hole.

Capturing the most energetic cosmic rays

International Nuclear Information System (INIS)

Mantsch, P.

1999-01-01

The methods of energy measurement applied to the most energetic cosmic rays are described. The rays are so rare that two gigantic systems of detectors are proposed to detect at least some of them (the Pierre Auger Project ). (Z.J.)

High frequency fishbone driven by passing energetic ions in tokamak plasmas

Science.gov (United States)

Wang, Feng; Yu, L. M.; Fu, G. Y.; Shen, Wei

2017-05-01

High frequency fishbone instability driven by passing energetic ions was first reported in the Princeton beta experiment with tangential neutral-beam-injection (Heidbrink et al 1986 Phys. Rev. Lett. 57 835-8). It could play an important role for ITER-like burning plasmas, where α particles are mostly passing particles. In this work, a generalized energetic ion distribution function and finite drift orbit width effect are considered to improve the theoretical model for passing particle driving fishbone instability. For purely passing energetic ions with zero drift orbit width, the kinetic energy δ {{W}k} is derived analytically. The derived analytic expression is more accurate as compared to the result of previous work (Wang 2001 Phys. Rev. Lett. 86 5286-8). For a generalized energetic ion distribution function, the fishbone dispersion relation is derived and is solved numerically. Numerical results show that broad and off-axis beam density profiles can significantly increase the beam ion beta threshold {βc} for instability and decrease mode frequency.

Energetic costs of performance in trained and untrained Anolis carolinensis lizards.

Science.gov (United States)

Lailvaux, Simon P; Wang, Andrew Z; Husak, Jerry F

2018-03-12

The energetic costs of performance constitute a non-trivial component of animals' daily energetic budgets. However, we currently lack an understanding of how those costs are partitioned among the various stages of performance development, maintenance, and production. We manipulated individual investment in performance by training Anolis carolinensis lizards for endurance or sprinting ability. We then measured energetic expenditure both at rest and immediately following exercise to test whether such training alters the maintenance and production costs of performance. Trained lizards had lower resting metabolic rates than controls, suggestive of a maintenance saving associated with enhanced performance as opposed to a cost. Production costs also differed, with sprint-trained lizards incurring the largest energetic performance cost and experiencing the longest recovery times compared to endurance trained and control animals. Although performance training modifies metabolism, production costs are probably the key drivers of trade-offs between performance and other life-history traits in this species. © 2018. Published by The Company of Biologists Ltd.

Energetic proton generation in ultra-intense laser-solid interactions

International Nuclear Information System (INIS)

Wilks, S.C.; Langdon, A.B.; Cowan, T.E.; Roth, M.; Singh, M.; Hatchett, S.; Key, M. H.; Pennington, D.; MacKinnon, A.; Snavely, R.A.

2001-01-01

An explanation for the energetic ions observed in the PetaWatt experiments is presented. In solid target experiments with focused intensities exceeding 10 20 W/cm 2 , high-energy electron generation, hard bremsstrahlung, and energetic protons have been observed on the backside of the target. In this report, an attempt is made to explain the physical process present that will explain the presence of these energetic protons, as well as explain the number, energy, and angular spread of the protons observed in experiment. In particular, we hypothesize that hot electrons produced on the front of the target are sent through to the back off the target, where they ionize the hydrogen layer there. These ions are then accelerated by the hot electron cloud, to tens of MeV energies in distances of order tens of μm, whereupon they end up being detected in the radiographic and spectrographic detectors

Chemical rocket propulsion a comprehensive survey of energetic materials

CERN Document Server

Shimada, Toru; Sinditskii, Valery; Calabro, Max

2017-01-01

Developed and expanded from the work presented at the New Energetic Materials and Propulsion Techniques for Space Exploration workshop in June 2014, this book contains new scientific results, up-to-date reviews, and inspiring perspectives in a number of areas related to the energetic aspects of chemical rocket propulsion. This collection covers the entire life of energetic materials from their conceptual formulation to practical manufacturing; it includes coverage of theoretical and experimental ballistics, performance properties, as well as laboratory-scale and full system-scale, handling, hazards, environment, ageing, and disposal. Chemical Rocket Propulsion is a unique work, where a selection of accomplished experts from the pioneering era of space propulsion and current technologists from the most advanced international laboratories discuss the future of chemical rocket propulsion for access to, and exploration of, space. It will be of interest to both postgraduate and final-year undergraduate students in...

Rural energetic development: cuban experience; El desarrollo energetico rural: experiencia cubana

Energy Technology Data Exchange (ETDEWEB)

Aguilera Barciela, M [Secretariado Ejecutivo, Comision Nacional de Energia, La Habana(Cuba)

1994-07-01

The development of electro energetic national system in Cuba has been directed to the following objectives: to brake the rural population's exodus toward the cities, electrification of dairy farm, interconnection to the system electro energetic of all the sugar central production, these improves the rural population's conditions life.

Energy transport by energetic electrons released during solar flares. I - Thermal versus nonthermal processes

Science.gov (United States)

Winglee, R. M.; Dulk, G. A.; Pritchett, P. L.

1988-01-01

The propagation of energetic electrons through a flaring flux tube is studied in an attempt to determine how the energy of the electrons is deposited in the flux tube. One-dimensional electrostatic particle simulations are used in the present investigation. As the energetic electrons propagate into the system, a return current of ambient plasma electrons and some of the energetic electrons is drawn into the energetic electron source. It is found that, as the ambient temperature relative to the ion temperature increases above about 3, the heated return-current electrons can excite ion-sound waves.

Introduction to global energetic problems

International Nuclear Information System (INIS)

Gicquel, R.

1992-01-01

This book gives a view on global energetic problems and proposes a thorough economic analysis on principle aspects taken into account: energy supply, depending energy sources and available technologic channels, relationships between macro-economy and energy demand, new size of energy problems (environmental effects, overcosts of renewable energy sources, necessity of an high technologic development...). 38 refs

About the wind energetics development

International Nuclear Information System (INIS)

Strebkov, D.S.; Kharitonov, V.P.; Murugov, V.P.; Sokol'skij, A.K.

1996-01-01

The review of wind power energetics state in USA, Europe, Russia is given. The data of EC on wind power plants production in different periods are presented. The directions of scientific-research works with the purpose of increasing the level of wind power industry of Russia corresponding to economics demands were elaborated. (author). 8 refs., 3 tabs

A comparison of energetic ions in the plasma depletion layer and the quasi-parallel magnetosheath

Science.gov (United States)

Fuselier, Stephen A.

1994-01-01

Energetic ion spectra measured by the Active Magnetospheric Particle Tracer Explorers/Charge Composition Explorer (AMPTE/CCE) downstream from the Earth's quasi-parallel bow shock (in the quasi-parallel magnetosheath) and in the plasma depletion layer are compared. In the latter region, energetic ions are from a single source, leakage of magnetospheric ions across the magnetopause and into the plasma depletion layer. In the former region, both the magnetospheric source and shock acceleration of the thermal solar wind population at the quasi-parallel shock can contribute to the energetic ion spectra. The relative strengths of these two energetic ion sources are determined through the comparison of spectra from the two regions. It is found that magnetospheric leakage can provide an upper limit of 35% of the total energetic H(+) population in the quasi-parallel magnetosheath near the magnetopause in the energy range from approximately 10 to approximately 80 keV/e and substantially less than this limit for the energetic He(2+) population. The rest of the energetic H(+) population and nearly all of the energetic He(2+) population are accelerated out of the thermal solar wind population through shock acceleration processes. By comparing the energetic and thermal He(2+) and H(+) populations in the quasi-parallel magnetosheath, it is found that the quasi-parallel bow shock is 2 to 3 times more efficient at accelerating He(2+) than H(+). This result is consistent with previous estimates from shock acceleration theory and simulati ons.

Simulation study of energetic ion transport due to Alfven eigenmodes in LHD plasma

International Nuclear Information System (INIS)

Todo, Yasushi; Nakajima, Noriyoshi; Osakabe, Masaki; Yamamoto, Satoshi; Spong, Donald A.

2008-01-01

The creation of holes and clumps in an energetic ion energy spectrum associated with Alfven eigenmodes was examined using the neutral particle analyzer (NPA) on the LHD shot no.47645. The difference in slowing-down times between the holes and clumps suggested that the energetic ions were transported over 10% of the plasma minor radius. The spatial profile and frequency of the Alfven eigenmodes were analyzed with the AE3D code. The phase space structures of the energetic ions on the NPA line-of-sight were investigated with Poincare plots, where an oscillating Alfven eigenmode was employed for earth plot. The phase space regions trapped by the Alfven eigenmodes appeared as islands in the Poincare plots. The radial width of the islands corresponded to the transport distance of the energetic ions. Since island width depends on Alfven eigenmode amplitude, it was found that Alfven eigenmodes with amplitude δB r /B - 10 -3 transported energetic ions over 10% of the minor radius. (author)

Is exposure to ionising radiation associated with childhood cardiac arrhythmia in the Russian territories contaminated by the Chernobyl fallout? A cross-sectional population-based study.

Science.gov (United States)

Jourdain, Jean-Rene; Landon, Geraldine; Clero, Enora; Doroshchenko, Vladimir; Silenok, Aleksandr; Kurnosova, Irina; Butsenin, Andrei; Denjoy, Isabelle; Franck, Didier; Heuze, Jean-Pierre; Gourmelon, Patrick

2018-03-25

To investigate childhood cardiac arrhythmia and chronic exposure to caesium-137 ( 137 Cs) resulting from the Chernobyl accident. Prospective cross-sectional study using exposed/unexposed design conducted in the Bryansk region from May 2009 to May 2013 on children selected on the basis of 137 Cs soil deposition: control territories ([ 137 Cs]555 kBq per square metre, where children were considered as exposed). Russian territories affected by the Chernobyl fallout (Bryansk region). This cross-sectional study included 18 152 children aged 2-18 years and living in the Bryansk region (Russia). All children received three medical examinations (ECG, echocardiography and 137 Cs whole-body activity measurement) and some of them were given with a 24-hour Holter monitoring and blood tests. Cardiac arrhythmia was diagnosed in 1172 children living in contaminated territories and 1354 children living in control territories. The crude prevalence estimated to 13.3% in contaminated territories was significantly lower than in control territories with 15.2% over the period 2009-2013 (PChernobyl fallout. The suspected increase of cardiac arrhythmia in children exposed to Chernobyl fallout is not confirmed. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Strong non-radial propagation of energetic electrons in solar corona

Science.gov (United States)

Klassen, A.; Dresing, N.; Gómez-Herrero, R.; Heber, B.; Veronig, A.

2018-06-01

Analyzing the sequence of solar energetic electron events measured at both STEREO-A (STA) and STEREO-B (STB) spacecraft during 17-21 July 2014, when their orbital separation was 34°, we found evidence of a strong non-radial electron propagation in the solar corona below the solar wind source surface. The impulsive electron events were associated with recurrent flare and jet (hereafter flare/jet) activity at the border of an isolated coronal hole situated close to the solar equator. We have focused our study on the solar energetic particle (SEP) event on 17 July 2014, during which both spacecraft detected a similar impulsive and anisotropic energetic electron event suggesting optimal connection of both spacecraft to the parent particle source, despite the large angular separation between the parent flare and the nominal magnetic footpoints on the source surface of STA and STB of 68° and 90°, respectively. Combining the remote-sensing extreme ultraviolet (EUV) observations, in-situ plasma, magnetic field, and energetic particle data we investigated and discuss here the origin and the propagation trajectory of energetic electrons in the solar corona. We find that the energetic electrons in the energy range of 55-195 keV together with the associated EUV jet were injected from the flare site toward the spacecraft's magnetic footpoints and propagate along a strongly non-radial and inclined magnetic field below the source surface. From stereoscopic (EUV) observations we estimated the inclination angle of the jet trajectory and the respective magnetic field of 63° ± 11° relative to the radial direction. We show how the flare accelerated electrons reach very distant longitudes in the heliosphere, when the spacecraft are nominally not connected to the particle source. This example illustrates how ballistic backmapping can occasionally fail to characterize the magnetic connectivity during SEP events. This finding also provides an additional mechanism (one among others

Conventional versus 3-D Echocardiography to Predict Arrhythmia Recurrence After Atrial Fibrillation Ablation.

Science.gov (United States)

Bossard, Matthias; Knecht, Sven; Aeschbacher, Stefanie; Buechel, Ronny R; Hochgruber, Thomas; Zimmermann, Andreas J; Kessel-Schaefer, Arnheid; Stephan, Frank-Peter; Völlmin, Gian; Pradella, Maurice; Sticherling, Christian; Osswald, Stefan; Kaufmann, Beat A; Conen, David; Kühne, Michael

2017-06-01

Arrhythmia recurrence after atrial fibrillation (AF) ablation remains high and requires repeat interventions in a substantial number of patients. We assessed the value of conventional and 3-D echocardiography to predict AF recurrence. Consecutive patients undergoing AF ablation by means of pulmonary vein isolation were included in a prospective registry. Echocardiograms were obtained prior to the ablation procedure, and analyzed offline in a standardized manner, including 3-D left atrial (LA) volumetry and determination of LA function and sphericity. The primary endpoint, AF recurrence (>30 seconds) between 3 to 12 months after AF ablation, was independently adjudicated. We included 276 patients (73% male, mean age 59.9 ± 9.9 years). Paroxysmal and persistent AF were present in 178 (64%) and 98 (36%) patients, respectively. Mean left ventricular ejection fraction and indexed LA volume in 3-D (LAVI) were 52 ± 12% and 42 ± 13 mL/m 2 , respectively. AF recurrence was observed in 110 (40%) patients after a single procedure. Median (interquartile range) time to AF recurrence was 123 (92; 236) days. In multivariable Cox regression models, the only predictors for AF recurrence were the minimal, maximal, and indexed 3-D LA volumes, P = 0.024, P = 0.016, and P = 0.014, respectively. Quartile specific analysis of 3-D LAVI showed an HR of 1.885 (95%CI 1.066-3.334; P for trend = 0.015) for the highest compared to the lowest quartile. Our results show the important role of LA volume for the long-term freedom from arrhythmia after AF ablation. These data also highlight the potential of 3-D echocardiography in this context and may facilitate patient selection for AF ablation. © 2017 Wiley Periodicals, Inc.

The impact of exercise on ventricular arrhythmias in adults with tetralogy of Fallot.

Science.gov (United States)

Ávila, Pablo; Marcotte, François; Dore, Annie; Mercier, Lise-Andrée; Shohoudi, Azadeh; Mongeon, François-Pierre; Mondésert, Blandine; Proietti, Anna; Ibrahim, Reda; Asgar, Anita; Poirier, Nancy; Khairy, Paul

2016-09-15

Sudden death of presumed arrhythmic etiology is the leading cause of mortality in adults with tetralogy of Fallot. To assess the impact of exercise on ventricular arrhythmias in adults with tetralogy of Fallot. Adults with repaired tetralogy of Fallot were randomized in a 2:1 ratio to an open-label trial of standard care versus 12weeks of supervised combined aerobic/resistance training with continuous Holter monitoring. Proportion of premature ventricular complexes (PVC) and runs of non-sustained ventricular tachycardia (NSVT) were assessed by mixed and Poisson regression models with generalized estimating equations for repeated measures. A total of 152 Holters were performed in 17 patients, median age 35 (interquartile range [IQR] 28, 42) years, 65% male, 13 of whom were randomized to exercise training. Baseline characteristics were similar between groups. Exercise training resulted in significant increases in peak oxygen uptake (11±19%, p=0.028), metabolic equivalents (11±18%, p=0.027), and exercise duration (8±10%, p=0.009) compared to no changes in controls. Frequent (≥30 per hour) PVCs were present in 46% of patients, couplets in 62%, and 3 to 7 beat runs of NSVT in 31%. The median proportion of PVCs was 1.93‰ (IQR 0.41, 5.89) at baseline and 1.45‰ (IQR 0.08, 2.76) during the initial exercise session (p=0.722), and remained stable over time (ß coefficient=-0.031, p=0.408). Runs of NSVT decreased significantly over time (ß coefficient=-0.032, p=0.018). In adults with repaired tetralogy of Fallot, exercise training is safe, improves exercise capacity, and appears to confer a beneficial effect on ventricular arrhythmias. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Aconitine-induced Ca2+ overload causes arrhythmia and triggers apoptosis through p38 MAPK signaling pathway in rats

International Nuclear Information System (INIS)

Sun, Gui-bo; Sun, Hong; Meng, Xiang-bao; Hu, Jin; Zhang, Qiang; Liu, Bo; Wang, Min; Xu, Hui-bo; Sun, Xiao-bo

2014-01-01

Aconitine is a major bioactive diterpenoid alkaloid with high content derived from herbal aconitum plants. Emerging evidence indicates that voltage-dependent Na + channels have pivotal roles in the cardiotoxicity of aconitine. However, no reports are available on the role of Ca 2+ in aconitine poisoning. In this study, we explored the importance of pathological Ca 2+ signaling in aconitine poisoning in vitro and in vivo. We found that Ca 2+ overload lead to accelerated beating rhythm in adult rat ventricular myocytes and caused arrhythmia in conscious freely moving rats. To investigate effects of aconitine on myocardial injury, we performed cytotoxicity assay in neonatal rat ventricular myocytes (NRVMs), as well as measured lactate dehydrogenase level in the culture medium of NRVMs and activities of serum cardiac enzymes in rats. The results showed that aconitine resulted in myocardial injury and reduced NRVMs viability dose-dependently. To confirm the pro-apoptotic effects, we performed flow cytometric detection, cardiac histology, transmission electron microscopy and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay. The results showed that aconitine stimulated apoptosis time-dependently. The expression analysis of Ca 2+ handling proteins demonstrated that aconitine promoted Ca 2+ overload through the expression regulation of Ca 2+ handling proteins. The expression analysis of apoptosis-related proteins revealed that pro-apoptotic protein expression was upregulated, and anti-apoptotic protein BCL-2 expression was downregulated. Furthermore, increased phosphorylation of MAPK family members, especially the P-P38/P38 ratio was found in cardiac tissues. Hence, our results suggest that aconitine significantly aggravates Ca 2+ overload and causes arrhythmia and finally promotes apoptotic development via phosphorylation of P38 mitogen-activated protein kinase. - Highlights: • Aconitine-induced Ca 2+ overload causes arrhythmia in rats

Energetic Cost of Ichthyophonus Infection in Juvenile Pacific Herring (Clupea pallasii

Directory of Open Access Journals (Sweden)

Johanna J. Vollenweider

2011-01-01

Full Text Available The energetic costs of fasting and Ichthyophonus infection were measured in juvenile Pacific herring (Clupea pallasii in a lab setting at three temperatures. Infected herring incurred significant energetic costs, the magnitude of which depended on fish condition at the time of infection (fat versus lean. Herring that were fed continually and were in relatively good condition at the time of infection (fat never stored lipid despite ad libitum feeding. In feeding herring, the energetic cost of infection was a 30% reduction in total energy content relative to controls 52 days post infection. Following food deprivation (lean condition, infection caused an initial delay in the compensatory response of herring. Thirty-one days after re-feeding, the energetic cost of infection in previously-fasted fish was a 32% reduction in total energy content relative to controls. Body composition of infected herring subsequently recovered to some degree, though infected herring never attained the same energy content as their continuously fed counterparts. Fifty-two days after re-feeding, the energetic cost of infection in previously-fasted fish was a 6% reduction in total energy content relative to controls. The greatest impacts of infection occurred in colder temperatures, suggesting Ichthyophonus-induced reductions in body condition may have greater consequences in the northern extent of herring's range, where juveniles use most of their energy reserves to survive their first winter.

Energetic Cost of Ichthyophonus Infection in Juvenile Pacific Herring (Clupea pallasii).

Science.gov (United States)

Vollenweider, Johanna J; Gregg, Jake L; Heintz, Ron A; Hershberger, Paul K

2011-01-01

The energetic costs of fasting and Ichthyophonus infection were measured in juvenile Pacific herring (Clupea pallasii) in a lab setting at three temperatures. Infected herring incurred significant energetic costs, the magnitude of which depended on fish condition at the time of infection (fat versus lean). Herring that were fed continually and were in relatively good condition at the time of infection (fat) never stored lipid despite ad libitum feeding. In feeding herring, the energetic cost of infection was a 30% reduction in total energy content relative to controls 52 days post infection. Following food deprivation (lean condition), infection caused an initial delay in the compensatory response of herring. Thirty-one days after re-feeding, the energetic cost of infection in previously-fasted fish was a 32% reduction in total energy content relative to controls. Body composition of infected herring subsequently recovered to some degree, though infected herring never attained the same energy content as their continuously fed counterparts. Fifty-two days after re-feeding, the energetic cost of infection in previously-fasted fish was a 6% reduction in total energy content relative to controls. The greatest impacts of infection occurred in colder temperatures, suggesting Ichthyophonus-induced reductions in body condition may have greater consequences in the northern extent of herring's range, where juveniles use most of their energy reserves to survive their first winter.

Energetic aspects of skeletal muscle contraction: implications of fiber types.

Science.gov (United States)

Rall, J A

1985-01-01

In this chapter fundamental energetic properties of skeletal muscles as elucidated from isolated muscle preparations are described. Implications of these intrinsic properties for the energetic characterization of different fiber types and for the understanding of locomotion have been considered. Emphasis was placed on the myriad of physical and chemical techniques that can be employed to understand muscle energetics and on the interrelationship of results from different techniques. The anaerobic initial processes which liberate energy during contraction and relaxation are discussed in detail. The high-energy phosphate (approximately P) utilized during contraction and relaxation can be distributed between actomyosin ATPase or cross-bridge cycling (70%) and the Ca2+ ATPase of the sacroplasmic reticulum (30%). Muscle shortening increases the rate of approximately P hydrolysis, and stretching a muscle during contraction suppresses the rate of approximately P hydrolysis. The economy of an isometric contraction is defined as the ratio of isometric mechanical response to energetic cost and is shown to be a fundamental intrinsic parameter describing muscle energetics. Economy of contraction varies across the animal kingdom by over three orders of magnitude and is different in different mammalian fiber types. In mammalian skeletal muscles differences in economy of contraction can be attributed mainly to differences in the specific actomyosin and Ca2+ ATPase of muscles. Furthermore, there is an inverse relationship between economy of contraction and maximum velocity of muscle shortening (Vmax) and maximum power output. This is a fundamental relationship. Muscles cannot be economical at developing and maintaining force and also exhibit rapid shortening. Interestingly, there appears to be a subtle system of unknown nature that modulates the Vmax and economy of contraction. Efficiency of a work-producing contraction is defined and contrasted to the economy of contraction

Los Alamos energetic particle sensor systems at geostationary orbit

International Nuclear Information System (INIS)

Baker, D.N.; Aiello, W.; Asbridge, J.R.; Belian, R.D.; Higbie, P.R.; Klebesadel, R.W.; Laros, J.G.; Tech, E.R.

1985-01-01

The Los Alamos National Laboratory has provided energetic particle sensors for a variety of spacecraft at the geostationary orbit (36,000 km altitude). The sensor system called the Charged Particle Analyzer (CPA) consists of four separate subsystems. The LoE and HiE subsystems measure electrons in the energy ranges 30 to 300 keV and 200 to 2000 keV, respectively. The LoP and HiP subsystems measure ions in the ranges 100 to 600 keV and 0.40 to 150 MeV, respectively. A separate sensor system called the spectrometer for energetic electrons (SEE) measures very high-energy electrons (2 to 15 MeV) using advanced scintillator design. In this paper we describe the relationship of operational anomalies and spacecraft upsets to the directly measured energetic particle environments at 6.6 R/sub E/. We also compare and contrast the CPA and SEE instrument design characteristics with the next generation of Los Alamos instruments to be flown at geostationary altitudes

Observation of energetic particle mode by using microwave reflectometer

International Nuclear Information System (INIS)

Tokuzawa, T.; Kawahata, K.; Sakakibara, S.; Toi, K.; Osakabe, M.; Yamamoto, S.

2006-01-01

Two heterodyne reflectometer systems are utilized for the fluctuation measurement in the Large Helical Device (LHD). By using the extraordinary polarized wave, we can measure the corresponding value to the combined fluctuation with the electron density and the magnetic field in the plasma core region even if the radial electron density profile is flat. E-band system has three channels of fixed frequencies of 78, 72, 65 GHz. The system is very convenient to observe magnetohydrodynamics (MHD) phenomena such as energetic particle driven Alfven eigenmodes, even if the system works as an interferometer mode. The detailed behaviour of the energetic particle mode is studied when low-n MHD burst is occurred. It seems to be caused that the spatial distribution of high energy particle is changed by such a MHD-burst. Also to know the radial distribution of MHD mode, frequency swept R-band reflectometer is applied for the first time. It seems to be successfully detected the energetic particle mode and toroidal Alfven eigenmode. (author)

Energetic materials standards – Chemical compatibility

NARCIS (Netherlands)

Tuukkanen, I.M.; Bouma, R.H.B.

2014-01-01

Subgroup A Energetic Materials Team, SG/A (EMT), develops and maintains standards that are relevant to all life-cycle phases of ammunition/weapon systems. STANAG 4147 is the standard regarding chemical compatibility of explosives with munition components, and is a document of prime importance.

Fractal ventilation enhances respiratory sinus arrhythmia

Directory of Open Access Journals (Sweden)

Girling Linda G

2005-05-01

Full Text Available Abstract Background Programming a mechanical ventilator with a biologically variable or fractal breathing pattern (an example of 1/f noise improves gas exchange and respiratory mechanics. Here we show that fractal ventilation increases respiratory sinus arrhythmia (RSA – a mechanism known to improve ventilation/perfusion matching. Methods Pigs were anaesthetised with propofol/ketamine, paralysed with doxacurium, and ventilated in either control mode (CV or in fractal mode (FV at baseline and then following infusion of oleic acid to result in lung injury. Results Mean RSA and mean positive RSA were nearly double with FV, both at baseline and following oleic acid. At baseline, mean RSA = 18.6 msec with CV and 36.8 msec with FV (n = 10; p = 0.043; post oleic acid, mean RSA = 11.1 msec with CV and 21.8 msec with FV (n = 9, p = 0.028; at baseline, mean positive RSA = 20.8 msec with CV and 38.1 msec with FV (p = 0.047; post oleic acid, mean positive RSA = 13.2 msec with CV and 24.4 msec with FV (p = 0.026. Heart rate variability was also greater with FV. At baseline the coefficient of variation for heart rate was 2.2% during CV and 4.0% during FV. Following oleic acid the variation was 2.1 vs. 5.6% respectively. Conclusion These findings suggest FV enhances physiological entrainment between respiratory, brain stem and cardiac nonlinear oscillators, further supporting the concept that RSA itself reflects cardiorespiratory interaction. In addition, these results provide another mechanism whereby FV may be superior to conventional CV.

An energetically consistent vertical mixing parameterization in CCSM4

DEFF Research Database (Denmark)

Nielsen, Søren Borg; Jochum, Markus; Eden, Carsten

2018-01-01

An energetically consistent stratification-dependent vertical mixing parameterization is implemented in the Community Climate System Model 4 and forced with energy conversion from the barotropic tides to internal waves. The structures of the resulting dissipation and diffusivity fields are compared......, however, depends greatly on the details of the vertical mixing parameterizations, where the new energetically consistent parameterization results in low thermocline diffusivities and a sharper and shallower thermocline. It is also investigated if the ocean state is more sensitive to a change in forcing...

Collective Thomson scattering in tokamaks having energetic ions

International Nuclear Information System (INIS)

Myer, R.C.; Woskov, P.P.; Machuzak, J.S.; Sigmar, D.J.; Cohn, D.R.; Bretz, N.L.; Efthimion, P.C.; Colestock, P.L.

1989-01-01

The authors discuss how collective Thomson scattering (CTS), using high power gyrotrons or long wavelength lasers,m shows promise as a powerful non-intrusive diagnostic of fast-ion transport as it may be capable of measuring the fast-ion velocity distribution and density profile with good spatial and temporal resolution. In addition, CTS may be used as a diagnostic for detecting localized power deposition in the background plasma. High power CTS systems are presently being planned for TFTR, JET, and CIT. Recent theoretical analysis suggests that an energetic (200-800 keV) He 3 minority can be produced in TFTR by ion cyclotron heating (ICH). Such an energetic population would be useful for simulating the energetic alpha-particles produced in a burning plasma. Since the ICH generated distribution is non-Maxwellian, the authors generalize the theoretical analysis of CTS to allow for particle distributions which can be represented by various orthogonal polynomial expansions. They evaluate the efficacy of CTS in detecting a fast He 3 component and determine the sensitivity of the diagnostic to the details of the ion distribution. In particular, the effectiveness of a planned 56 GHz gyrotron CTS diagnostic for TFTR is evaluated

Nanostructured energetic materials derived from sol-gel chemistry

International Nuclear Information System (INIS)

Simpson, R L; Tillotson, T M; Hrubesh, L W; Gash, A E

2000-01-01

Initiation and detonation properties are dramatically affected by an energetic material's microstructural properties. Sol-gel chemistry allows intimacy of mixing to be controlled and dramatically improved over existing methodologies. One material goal is to create very high power energetic materials which also have high energy densities. Using sol-gel chemistry we have made a nanostructured composite energetic material. Here a solid skeleton of fuel, based on resorcinol-formaldehyde, has nanocrystalline ammonium perchlorate, the oxidizer, trapped within its pores. At optimum stoichiometry it has approximately the energy density of HMX. Transmission electron microscopy indicated no ammonium perchlorate crystallites larger than 20 nm while near-edge soft x-ray absorption microscopy showed that nitrogen was uniformly distributed, at least on the scale of less than 80 nm. Small-angle neutron scattering studies were conducted on the material. Those results were consistent with historical ones for this class of nanostructured materials. The average skeletal primary particle size was on the order of 2.7 nm, while the nanocomposite showed the growth of small 1 nm size crystals of ammonium perchlorate with some clustering to form particles greater than 10 nm

Advances in Cell Transplantation Therapy for Diseased Myocardium

Directory of Open Access Journals (Sweden)

Outi M. Villet

2011-01-01

Full Text Available The overall objective of cell transplantation is to repopulate postinfarction scar with contractile cells, thus improving systolic function, and to prevent or to regress the remodeling process. Direct implantation of isolated myoblasts, cardiomyocytes, and bone-marrow-derived cells has shown prospect for improved cardiac performance in several animal models and patients suffering from heart failure. However, direct implantation of cultured cells can lead to major cell loss by leakage and cell death, inappropriate integration and proliferation, and cardiac arrhythmia. To resolve these problems an approach using 3-dimensional tissue-engineered cell constructs has been investigated. Cell engineering technology has enabled scaffold-free sheet development including generation of communication between cell graft and host tissue, creation of organized microvascular network, and relatively long-term survival after in vivo transplantation.

Elements of the new energetic policy in Macedonia

International Nuclear Information System (INIS)

Tomovski, Aleksandar

1995-01-01

In the field of the energetic policy and development in both energy production and energy consumption in Macedonia, one can fill an uncertainty and development concept absence. It is clear that this is a result of the stress that Macedonian economy suffers from after the disintegration of the former Yugoslavia as a market and economic unit, as well as of the establishment of different economic and market norms. It is obvious that in the energetics, as one of the basic economic sectors,the situation has to be stabilized very soon as well as in advance analysed right decisions have to be made. (author). 1 ill

Very High Performance High Nitrogen Energetic Ingredients and Energetic Polymers for Structural Components

Science.gov (United States)

2011-12-31

13. SUPPLEMENTARY NOTES SoUoWtoo^ 14. ABSTRACT This project investigated new energetic materials for use with a triazole cured binder system ...The reaction was repeated using two equivalents of KH. An even more insoluble product was obtained. Figure 8 and 9 show the C-13 and N-15 CP/MAS...Sonnenberg, M. Hada, M. Ehara, K. Toyota , R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda , O. Kitao, H. Nakai, T. Vreven, J. A. Montgomery, Jr

Toward Personalized Medicine: Using Cardiomyocytes Differentiated From Urine-Derived Pluripotent Stem Cells to Recapitulate Electrophysiological Characteristics of Type 2 Long QT Syndrome.

Science.gov (United States)

Jouni, Mariam; Si-Tayeb, Karim; Es-Salah-Lamoureux, Zeineb; Latypova, Xenia; Champon, Benoite; Caillaud, Amandine; Rungoat, Anais; Charpentier, Flavien; Loussouarn, Gildas; Baró, Isabelle; Zibara, Kazem; Lemarchand, Patricia; Gaborit, Nathalie

2015-09-01

Human genetically inherited cardiac diseases have been studied mainly in heterologous systems or animal models, independent of patients' genetic backgrounds. Because sources of human cardiomyocytes (CMs) are extremely limited, the use of urine samples to generate induced pluripotent stem cell-derived CMs would be a noninvasive method to identify cardiac dysfunctions that lead to pathologies within patients' specific genetic backgrounds. The objective was to validate the use of CMs differentiated from urine-derived human induced pluripotent stem (UhiPS) cells as a new cellular model for studying patients' specific arrhythmia mechanisms. Cells obtained from urine samples of a patient with long QT syndrome who harbored the HERG A561P gene mutation and his asymptomatic noncarrier mother were reprogrammed using the episomal-based method. UhiPS cells were then differentiated into CMs using the matrix sandwich method.UhiPS-CMs showed proper expression of atrial and ventricular myofilament proteins and ion channels. They were electrically functional, with nodal-, atrial- and ventricular-like action potentials recorded using high-throughput optical and patch-clamp techniques. Comparison of HERG expression from the patient's UhiPS-CMs to the mother's UhiPS-CMs showed that the mutation led to a trafficking defect that resulted in reduced delayed rectifier K(+) current (IKr). This phenotype gave rise to action potential prolongation and arrhythmias. UhiPS cells from patients carrying ion channel mutations can be used as novel tools to differentiate functional CMs that recapitulate cardiac arrhythmia phenotypes. © 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Energetics and Defect Interactions of Complex Oxides for Energy Applications

Science.gov (United States)

Solomon, Jonathan Michael

The goal of this dissertation is to employ computational methods to gain greater insights into the energetics and defect interactions of complex oxides that are relevant for today's energy challenges. To achieve this goal, the development of novel computational methodologies are required to handle complex systems, including systems containing nearly 650 ions and systems with tens of thousands of possible atomic configurations. The systems that are investigated in this dissertation are aliovalently doped lanthanum orthophosphate (LaPO4) due to its potential application as a proton conducting electrolyte for intermediate temperature fuel cells, and aliovalently doped uranium dioxide (UO2) due to its importance in nuclear fuel performance and disposal. First we undertake density-functional-theory (DFT) calculations on the relative energetics of pyrophosphate defects and protons in LaPO4, including their binding with divalent dopant cations. In particular, for supercell calculations with 1.85 mol% Sr doping, we investigate the dopant-binding energies for pyrophosphate defects to be 0.37 eV, which is comparable to the value of 0.34 eV calculated for proton-dopant binding energies in the same system. These results establish that dopant-defect interactions further stabilize proton incorporation, with the hydration enthalpies when the dopants are nearest and furthest from the protons and pyrophosphate defects being -1.66 eV and -1.37 eV, respectively. Even though our calculations show that dopant binding enhances the enthalpic favorability of proton incorporation, they also suggest that such binding is likely to substantially lower the kinetic rate of hydrolysis of pyrophosphate defects. We then shift our focus to solid solutions of fluorite-structured UO 2 with trivalent rare earth fission product cations (M3+=Y, La) using a combination of ionic pair potential and DFT based methods. Calculated enthalpies of formation with respect to constituent oxides show higher

Physics with energetic radioactive ion beams

International Nuclear Information System (INIS)

Henning, W.F.

1996-01-01

Beams of short-lived, unstable nuclei have opened new dimensions in studies of nuclear structure and reactions. Such beams also provide key information on reactions that take place in our sun and other stars. Status and prospects of the physics with energetic radioactive beams are summarized

Inhalation of diluted diesel engine emission impacts heart rate variability and arrhythmia occurrence in a rat model of chronic ischemic heart failure

Energy Technology Data Exchange (ETDEWEB)

Anselme, Frederic [Rouen University Hospital, Service de Cardiologie, Rouen (France); Loriot, Stephane; Henry, Jean-Paul; Thuillez, Christian; Morin, Jean-Paul [University of Rouen France, INSERM U644, School of Medicine-Pharmacy, Rouen, Cedex (France); Dionnet, Frederic [Centre d' Etudes et de Recherches Technologiques en Aerothermique et Moteurs, Saint Etienne du Rouvray (France); Napoleoni, Jean-Gerard [EMKA Technologies, Paris (France)

2007-04-15

Both increase in cardiac arrhythmia incidence and decrease in heart rate variability (HRV) have been described following human and experimental animal exposures to air pollutants. However, the potential causal relationship between these two factors remains unclear. Incidence of ventricular arrhythmia and HRV were evaluated during and after a 3 h period of Diesel engine exhaust exposure in ten healthy and ten chronic ischemic heart failure (CHF, 3 months after coronary ligation) Wistar rats using implantable ECG telemetry. Air pollutants were delivered to specifically designed whole body individual exposure chambers at particulate matter concentrations similar to those measured inside cabins of cars inserted in congested urban traffic. Recordings were obtained from unrestraint and unsedated vigil rats. Immediate decrease in RMSSD was observed in both healthy (6.64 {+-} 2.62 vs. 4.89 {+-} 1.67 ms, P < 0.05) and CHF rats (8.01 {+-} 0.89 vs. 6.6 {+-} 1.37 ms, P < 0.05) following exposure. An immediate 200-500% increase in ventricular premature beats was observed in CHF rats only. Whereas HRV progressively returned to baseline values within 2.5 h after exposure start, the proarrhythmic effect persisted as late as 5 h after exposure termination in CHF rats. Persistence of ventricular proarrhythmic effects after HRV normalization suggests that HRV reduction is not the mechanism of cardiac arrhythmias in this model. Our methodological approach, closely reflecting the real clinical situations, appeared to be a unique tool to provide further insight into the pathophysiological mechanisms of traffic related airborne pollution health impact. (orig.)

Energetic Particle Estimates for Stellar Flares

Science.gov (United States)

Youngblood, Allison; Chamberlin, Phil; Woods, Tom

2018-01-01

In the heliosphere, energetic particles are accelerated away from the Sun during solar flares and/or coronal mass ejections where they frequently impact the Earth and other solar system bodies. Solar (or stellar) energetic particles (SEPs) not only affect technological assets, but also influence mass loss and chemistry in planetary atmospheres (e.g., depletion of ozone). SEPs are increasingly recognized as an important factor in assessing exoplanet habitability, but we do not yet have constraints on SEP emission from any stars other than the Sun. Until indirect measurements are available, we must assume solar-like particle production and apply correlations between solar flares and SEPs detected near Earth to stellar flares. We present improved scaling relations between solar far-UV flare flux and >10 MeV proton flux near Earth. We apply these solar scaling relations to far-UV flares from exoplanet host stars and discuss the implications for modeling chemistry and mass loss in exoplanet atmospheres.

Association of ventricular arrhythmia and in-hospital mortality in stroke patients in Florida: A nonconcurrent prospective study.

Science.gov (United States)

Dahlin, Arielle A; Parsons, Chase C; Barengo, Noël C; Ruiz, Juan Gabriel; Ward-Peterson, Melissa; Zevallos, Juan Carlos

2017-07-01

Stroke remains one of the leading causes of death in the United States. Current evidence identified electrocardiographic abnormalities and cardiac arrhythmias in 50% of patients with an acute stroke. The purpose of this study was to assess whether the presence of ventricular arrhythmia (VA) in adult patients hospitalized in Florida with acute stroke increased the risk of in-hospital mortality.Secondary data analysis of 215,150 patients with ischemic and hemorrhagic stroke hospitalized in the state of Florida collected by the Florida Agency for Healthcare Administration from 2008 to 2012. The main outcome for this study was in-hospital mortality. The main exposure of this study was defined as the presence of VA. VA included the ICD-9 CM codes: paroxysmal ventricular tachycardia (427.1), ventricular fibrillation (427.41), ventricular flutter (427.42), ventricular fibrillation and flutter (427.4), and other - includes premature ventricular beats, contractions, or systoles (427.69). Differences in demographic and clinical characteristics and hospital outcomes were assessed between patients who developed versus did not develop VA during hospitalization (χ and t tests). Binary logistic regression was used to estimate unadjusted and adjusted odds ratios and 95% confidence intervals (CIs) between VA and in-hospital mortality.VA was associated with an increased risk of in-hospital mortality after adjusting for all covariates (odds ratio [OR]: 1.75; 95% CI: 1.6-1.2). There was an increased in-hospital mortality in women compared to men (OR: 1.1; 95% CI: 1.1-1.14), age greater than 85 years (OR: 3.9, 95% CI: 3.5-4.3), African Americans compared to Whites (OR: 1.1; 95% CI: 1.04-1.2), diagnosis of congestive heart failure (OR: 2.1; 95% CI: 2.0-2.3), and atrial arrhythmias (OR: 2.1, 95% CI: 2.0-2.2). Patients with hemorrhagic stroke had increased odds of in-hospital mortality (OR: 9.0; 95% CI: 8.6-9.4) compared to ischemic stroke.Identifying VAs in stroke patients may help in

Local protoplanetary disk ionisation by T Tauri star energetic particles

Science.gov (United States)

Fraschetti, F.; Drake, J.; Cohen, O.; Garraffo, C.

2017-10-01

The evolution of protoplanetary disks is believed to be driven largely by viscosity. The ionization of the disk that gives rise to viscosity is caused by X-rays from the central star or by energetic particles released by shock waves travelling into the circumstellar medium. We have performed test-particle numerical simulations of GeV-scale protons traversing a realistic magnetised wind of a young solar mass star with a superposed small-scale turbulence. The large-scale field is generated via an MHD model of a T Tauri wind, whereas the isotropic (Kolmogorov power spectrum) turbulent component is synthesised along the particles' trajectories. We have combined Chandra observations of T Tauri flares with solar flare scaling for describing the energetic particle spectrum. In contrast with previous models, we find that the disk ionization is dominated by X-rays except within narrow regions where the energetic particles are channelled onto the disk by the strongly tangled and turbulent field lines; the radial thickness of such regions broadens with the distance from the central star (5 stellar radii or more). In those regions, the disk ionization due to energetic particles can locally dominate the stellar X-rays, arguably, out to large distances (10, 100 AU) from the star.

QRS Complex Enlargement as a Predictor of Ventricular Arrhythmias in Patients Affected by Surgically Treated Tetralogy of Fallot: A Comprehensive Literature Review and Historical Overview

Science.gov (United States)

Bassareo, Pier Paolo; Mercuro, Giuseppe

2013-01-01

Tetralogy of Fallot (TOF) is a congenital heart disease frequently treated by surgical repair to relieve symptoms and improve survival. However, despite the performing of an optimal surgical repair, TOF patients are at times characterized by a poor long-term survival rate, likely due to cardiac causes such as ventricular arrhythmias, with subsequent sudden death. In the 80s it was irrefutably demonstrated that QRS prolongation ≥180 msec at basal electrocardiogram is a strong predictor for refining risk stratification for ventricular tachycardia in these patients. The aim of this research was to undertake a review of all studies conducted to assess the impact of QRS duration on the development of life-threatening ventricular arrhythmias in repaired TOF subjects. PMID:23509638

Assessment of CRBR core disruptive accident energetics

International Nuclear Information System (INIS)

Theofanous, T.G.; Bell, C.R.

1984-03-01

The results of an independent assessment of core disruptive accident energetics for the Clinch River Breeder Reactor are presented in this document. This assessment was performed for the Nuclear Regulatory Commission under the direction of the CRBR Program Office within the Office of Nuclear Reactor Regulation. It considered in detail the accident behavior for three accident initiators that are representative of three different classes of events; unprotected loss of flow, unprotected reactivity insertion, and protected loss of heat sink. The primary system's energetics accommodation capability was realistically, yet conservatively, determined in terms of core events. This accommodation capability was found to be equivalent to an isentropic work potential for expansion to one atmosphere of 2550 MJ or a ramp rate of about 200 $/s applied to a classical two-phase disassembly

Fatal cardiac arrhythmia after repeated exposure to 1,1-difluoroethane (DFE).

Science.gov (United States)

Avella, Joseph; Wilson, James C; Lehrer, Michael

2006-03-01

A 42-year-old man was found dead after repeated exposure to 1,1-difluoroethane (DFE, Freon 152a), a propellant found in CRC Duster, a product intended for the removal of dust and lint. Toxicologic analysis detected DFE in femoral blood 136.3 mg/L, brain 117.5 mg/kg, liver 87.6 mg/kg, lung 60.3 mg/kg, adipose 235.7 mg/kg, and vitreous fluid 25.1 mg/L. The cause of death was determined to be a fatal cardiac arrhythmia due to intoxication with 1,1-difluoroethane. After comparison to previously published cases involving DFE, we suggest that analysis of adipose tissue for DFE and similar compounds, along with blood and other tissues, may be useful in distinguishing between acute versus chronic exposure. Adipose may also be a valuable alternate specimen for detection in cases where loss or elimination from blood is likely to have occurred.

Percutaneous autonomic neural modulation: A novel technique to treat cardiac arrhythmia

International Nuclear Information System (INIS)

DeSimone, Christopher V.; Madhavan, Malini; Venkatachalam, Kalpathi L.; Knudson, Mark B.; Asirvatham, Samuel J.

2013-01-01

Ablation and anti-arrhythmic medications have shown promise but have been met with varying success and unwanted side effects such as myocardial injury, arrhythmias, and morbidity from invasive surgical intervention. The answer to improving efficacy of ablation may include modulation of the cardiac aspect of the autonomic nervous system. Our lab has developed a novel approach and device to navigate the oblique sinus and to use DC current and saline/alcohol irrigation to selectively stimulate and block the autonomic ganglia found on the epicardial side of the heart. This novel approach minimizes myocardial damage from thermal injury and provides a less invasive and targeted approach. For feasibility, proof-of-concept, and safety monitoring, we carried out canine studies to test this novel application. Our results suggest a safer and less invasive way of modulating arrhythmogenic substrate that may lead to improved treatment of AF in humans

Percutaneous autonomic neural modulation: A novel technique to treat cardiac arrhythmia

Energy Technology Data Exchange (ETDEWEB)

DeSimone, Christopher V.; Madhavan, Malini [Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, MN (United States); Venkatachalam, Kalpathi L. [Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Jacksonville, FL (United States); Knudson, Mark B. [Mayo Clinic, Rochester, MN (United States); EnteroMedics, EnteroMedics, St. Paul, MN (United States); Asirvatham, Samuel J., E-mail: asirvatham.samuel@mayo.edu [Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, MN (United States); Pediatric Cardiology, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN (United States)

2013-05-15

Ablation and anti-arrhythmic medications have shown promise but have been met with varying success and unwanted side effects such as myocardial injury, arrhythmias, and morbidity from invasive surgical intervention. The answer to improving efficacy of ablation may include modulation of the cardiac aspect of the autonomic nervous system. Our lab has developed a novel approach and device to navigate the oblique sinus and to use DC current and saline/alcohol irrigation to selectively stimulate and block the autonomic ganglia found on the epicardial side of the heart. This novel approach minimizes myocardial damage from thermal injury and provides a less invasive and targeted approach. For feasibility, proof-of-concept, and safety monitoring, we carried out canine studies to test this novel application. Our results suggest a safer and less invasive way of modulating arrhythmogenic substrate that may lead to improved treatment of AF in humans.

A multi-scale methodology to model damage, deformation and ignition of highly-filled energetic materials

Energy Technology Data Exchange (ETDEWEB)

Vivier, G. [Paris Univ., Paris (France). LMT Cachan; CEA Le Ripault, Monts (France); Trumel, H. [CEA Le Ripault, Monts (France); Hild, F. [Paris Univ., Paris (France). LMT Cachan

2009-07-01

The kinetic energy that occurs when energetic materials are impacted can be converted to heat through dissipative deformation processes while the macroscopic temperature remains unaffected. In this study, a thermodynamics-based approach was used to model the elasto-plastic behaviour that occurs during the deformation process of microstructures. Macroscopic material was modelled as a statistical distribution of unit cells containing a crack grain embedded in an elastic mortar-like matrix. A mesoscopic unit cell model was also developed under confined shear. The study demonstrated that stored energy is a non-negligible part of the total energy of the system, and that stored energy can be released during the unloading process. It was concluded that the mesoscopic analysis of the cracked cell demonstrates that continuum thermodynamics can be used to predict hot spots induced by friction. 7 refs., 7 figs.

MOISTURE HUMIDITY EQUILIBRIUM OF WOOD CHIPS FROM ENERGETIC CROPS

Directory of Open Access Journals (Sweden)

Jan Barwicki

2008-09-01

Full Text Available Processes occurring during storage of wood chips for energetic or furniture industry purposes were presented. As a result of carried out investigations, dependences of temperature and relative humidity changes of surrounding air were shown. Modified Henderson equation can be utilized for computer simulation of storing and drying processes concerning wood chips for energetic and furniture industry purposes. It reflects also obtained results from experiments carried out with above mentioned material. Using computer simulation program we can examine different wood chips storing conditions to avoid overheating and loss problems.

Genetically engineered excitable cardiac myofibroblasts coupled to cardiomyocytes rescue normal propagation and reduce arrhythmia complexity in heterocellular monolayers.

Directory of Open Access Journals (Sweden)

Luqia Hou

Full Text Available The use of genetic engineering of unexcitable cells to enable expression of gap junctions and inward rectifier potassium channels has suggested that cell therapies aimed at establishing electrical coupling of unexcitable donor cells to host cardiomyocytes may be arrhythmogenic. Whether similar considerations apply when the donor cells are electrically excitable has not been investigated. Here we tested the hypothesis that adenoviral transfer of genes coding Kir2.1 (I(K1, Na(V1.5 (I(Na and connexin-43 (Cx43 proteins into neonatal rat ventricular myofibroblasts (NRVF will convert them into fully excitable cells, rescue rapid conduction velocity (CV and reduce the incidence of complex reentry arrhythmias in an in vitro model.We used adenoviral (Ad- constructs encoding Kir2.1, Na(V1.5 and Cx43 in NRVF. In single NRVF, Ad-Kir2.1 or Ad-Na(V1.5 infection enabled us to regulate the densities of I(K1 and I(Na, respectively. At varying MOI ratios of 10/10, 5/10 and 5/20, NRVF co-infected with Ad-Kir2.1+ Na(V1.5 were hyperpolarized and generated action potentials (APs with upstroke velocities >100 V/s. However, when forming monolayers only the addition of Ad-Cx43 made the excitable NRVF capable of conducting electrical impulses (CV = 20.71±0.79 cm/s. When genetically engineered excitable NRVF overexpressing Kir2.1, Na(V1.5 and Cx43 were used to replace normal NRVF in heterocellular monolayers that included neonatal rat ventricular myocytes (NRVM, CV was significantly increased (27.59±0.76 cm/s vs. 21.18±0.65 cm/s, p<0.05, reaching values similar to those of pure myocytes monolayers (27.27±0.72 cm/s. Moreover, during reentry, propagation was faster and more organized, with a significantly lower number of wavebreaks in heterocellular monolayers formed by excitable compared with unexcitable NRVF.Viral transfer of genes coding Kir2.1, Na(V1.5 and Cx43 to cardiac myofibroblasts endows them with the ability to generate and propagate APs. The results

Global Positioning System (GPS) Energetic Particle Data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Energetic particle data from the CXD and BDD instrument on the GPS constellation are available to the space weather research community. The release of these data...

Wrong directions of the energetic policy; Descaminhos da politica energetica

Energy Technology Data Exchange (ETDEWEB)

Carvalho, Joaquim Francisco

1997-12-31

The energetic planning should take an important role in the formulation of the economic and social development policy of any country. This work presents the opinion of the author in relation to this issue in what concerns the Brazilian experience. Several actions considered wrong by the author, which were taken by the government in what concerns energetic policy are presented and their expected consequences in the near future are discussed 6 refs., 1 tab.

Induction of chagasic-like arrhythmias in the isolated beating hearts of healthy rats perfused with Trypanosoma cruzi-conditioned medium

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H. Rodriguez-Angulo

2013-01-01

Full Text Available Chagas' myocardiopathy, caused by the intracellular protozoan Trypanosoma cruzi, is characterized by microvascular alterations, heart failure and arrhythmias. Ischemia and arrythmogenesis have been attributed to proteins shed by the parasite, although this has not been fully demonstrated. The aim of the present investigation was to study the effect of substances shed by T. cruzi on ischemia/reperfusion-induced arrhythmias. We performed a triple ischemia-reperfusion (I/R protocol whereby the isolated beating rat hearts were perfused with either Vero-control or Vero T. cruzi-infected conditioned medium during the different stages of ischemia and subsequently reperfused with Tyrode's solution. ECG and heart rate were recorded during the entire experiment. We observed that triple I/R-induced bradycardia was associated with the generation of auricular-ventricular blockade during ischemia and non-sustained nodal and ventricular tachycardia during reperfusion. Interestingly, perfusion with Vero-infected medium produced a delay in the reperfusion-induced recovery of heart rate, increased the frequency of tachycardic events and induced ventricular fibrillation. These results suggest that the presence of parasite-shed substances in conditioned media enhances the arrhythmogenic effects that occur during the I/R protocol.