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Sample records for documented cardiac arrhythmias

  1. Carbon monoxide exposure of subjects with documented cardiac arrhythmias

    SciTech Connect

    Chaitman, B.R.; Dahms, T.E.; Byers, S.; Carroll, L.W.; Younis, L.T.; Wiens, R.D. )

    1992-09-01

    The impact of low-level carbon monoxide exposure on ventricular arrhythmia frequency in patients with ischemic heart disease has not been thoroughly studied. The issue is of concern because of the potential proarrhythmic effect of carbon monoxide in patients with ischemic heart disease. We studied 30 subjects with well-documented coronary artery disease who had an average of at least 30 ventricular ectopic beats per hour over a 20-hour monitoring interval. By using appropriate inclusion and exclusion criteria, subjects were selected and enrolled in a randomized double-blind study to determine the effects of carbon monoxide exposure on ventricular arrhythmia frequency at rest, during exercise, and during ambulatory activities. The carbon monoxide exposure was designed to result in 3% or 5% carboxyhemoglobin levels, as measured by gas chromatography. The carbon monoxide exposure protocol produced target levels in 60 minutes, and the levels were maintained for an additional 90 minutes to provide adequate time to assess the impact of carbon monoxide on the frequency of ventricular ectopic beats. The data on total and repetitive ventricular arrhythmias were analyzed for seven specific time intervals: (1) two hours before carbon monoxide exposure; (2) during the two-hour carbon monoxide or air exposure; (3) during a two-hour rest period; (4) during an exercise period; (5) during an exercise recovery period; (6) six hours after carbon monoxide or air exposure; and (7) approximately 10 hours after exposure, or the remaining recording interval on the Holter monitor. There was no increase in ventricular arrhythmia frequency after carbon monoxide exposure, regardless of the level of carboxyhemoglobin or the type of activity.

  2. Cardiac arrhythmias in pregnancy.

    PubMed

    Knotts, Robert J; Garan, Hasan

    2014-08-01

    As more women with repaired congenital heart disease survive to their reproductive years and many other women are delaying pregnancy until later in life, a rising concern is the risk of cardiac arrhythmias during pregnancy. Naturally occurring cardiovascular changes during pregnancy increase the likelihood that a recurrence of a previously experienced cardiac arrhythmia or a de novo arrhythmia will occur. Arrhythmias should be thoroughly investigated to determine if there is a reversible etiology, and risks/benefits of treatment options should be fully explored. We discuss the approach to working up and treating various arrhythmias during pregnancy with attention to fetal and maternal risks as well as treatment of fetal arrhythmias. Acute management in stable patients includes close monitoring and intravenous pharmacologic therapy, while DC cardioversion should be used to terminate arrhythmias in hemodynamically unstable patients. Long-term management may require continued oral antiarrhythmic therapy, with particular attention to fetal safety, to prevent complications associated with arrhythmias.

  3. Autoantibodies and Cardiac Arrhythmias

    PubMed Central

    Lee, Hon-Chi; Huang, Kristin T. L.; Wang, Xiao-Li; Shen, Win-Kuang

    2013-01-01

    Autoimmune diseases are associated with significant morbidity and mortality, afflicting about 5% of the population of the United States. They encompass a wide range of disorders that affect all organs of the human body and have a predilection for women. In the past, autoimmune pathogenesis was not thought to be a major mechanism for cardiovascular disorders, and potential relationships remain understudied. However, accumulating evidence suggests that a number of vascular and cardiac conditions are autoimmune-mediated. Recent studies indicate that autoantibodies play an important role in the development of cardiac arrhythmias, including atrial fibrillation, modulation of autonomic influences on heart rate and rhythm, conduction system abnormalities, and ventricular arrhythmias. This manuscript will review the current evidence for the role of autoantibodies in the development of cardiac arrhythmias. PMID:21740882

  4. [Psychosomatic aspects of cardiac arrhythmias].

    PubMed

    Siepmann, Martin; Kirch, Wilhelm

    2010-07-01

    Emotional stress facilitates the occurrence of cardiac arrhythmias including sudden cardiac death. The prevalence of anxiety and depression is increased in cardiac patients as compared to the normal population. The risk of cardiovascular mortality is enhanced in patients suffering from depression. Comorbid anxiety disorders worsen the course of cardiac arrhythmias. Disturbance of neurocardiac regulation with predominance of the sympathetic tone is hypothesized to be causative for this. The emotional reaction to cardiac arrhythmias is differing to a large extent between individuals. Emotional stress may result from coping with treatment of cardiac arrhythmias. Emotional stress and cardiac arrhythmias may influence each other in the sense of a vicious circle. Somatoform cardiac arrhythmias are predominantly of psychogenic origin. Instrumental measures and frequent contacts between physicians and patients may facilitate disease chronification. The present review is dealing with the multifaceted relationships between cardiac arrhythmias and emotional stress. The underlying mechanisms and corresponding treatment modalities are discussed.

  5. Carbon monoxide exposure of subjects with documented cardiac arrhythmias. Research report, August 1987-July 1991

    SciTech Connect

    Chaitman, B.R.; Dahms, T.E.; Byers, S.; Carroll, L.W.; Younis, L.T.

    1992-09-01

    The authors studied 30 subjects with well-documented coronary artery disease who had an average of at least 30 ventricular ectopic beats per hour over a 20-hour monitoring interval. Subjects were selected and enrolled in a randomized double-blind study; the carbon monoxide exposure was designed to result in 3% or 5% carboxyhemoglobin levels, as measured by gas chromatography. Total and repetitive ventricular arrhythmias were measured for four specific time intervals: (1) two hours before carbon monoxide exposure; (2) during the two-hour carbon monoxide exposure; (3) six hours after carbon monoxide exposure; and (4) approximately 10 hours after exposure, or the remaining recording interval on the Holter monitor. There was no increase in ventricular arrhythmia frequency after carbon monoxide exposure, regardless of the level of carboxyhemoglobin or the type of activity. During steady-state conditions at rest, the number of ventricular ectopic beats per hour was 115 + or - 153 (SD) for room air exposure (0.7% carboxyhemoglobin), 121 + or - 171 for the lower carbon monoxide exposure (3.2% carboxyhemoglobin), and 94 + or - 129 for the higher carbon monoxide exposure (5.1% carboxyhemoglobin). The frequency of complex ventricular ectopy was not altered at the levels of carbon monoxide studied. Secondary analysis of the impact of carbon monoxide on ventricular ectopic beat frequency stratified by baseline ejection fraction, baseline ventricular ectopic beat frequency, and exercise-induced ST-segment changes did not indicate an effect of carbon monoxide on ventricular arrhythmias. However, patients with symptomatic ventricular arrhythmias and symptomatic myocardial ischemia were excluded from the present study.

  6. Mechanisms of cardiac arrhythmias

    PubMed Central

    Tse, Gary

    2015-01-01

    Blood circulation is the result of the beating of the heart, which provides the mechanical force to pump oxygenated blood to, and deoxygenated blood away from, the peripheral tissues. This depends critically on the preceding electrical activation. Disruptions in the orderly pattern of this propagating cardiac excitation wave can lead to arrhythmias. Understanding of the mechanisms underlying their generation and maintenance requires knowledge of the ionic contributions to the cardiac action potential, which is discussed in the first part of this review. A brief outline of the different classification systems for arrhythmogenesis is then provided, followed by a detailed discussion for each mechanism in turn, highlighting recent advances in this area. PMID:27092186

  7. Data analysis in cardiac arrhythmias.

    PubMed

    Rodrigo, Miguel; Pedrón-Torecilla, Jorge; Hernández, Ismael; Liberos, Alejandro; Climent, Andreu M; Guillem, María S

    2015-01-01

    Cardiac arrhythmias are an increasingly present in developed countries and represent a major health and economic burden. The occurrence of cardiac arrhythmias is closely linked to the electrical function of the heart. Consequently, the analysis of the electrical signal generated by the heart tissue, either recorded invasively or noninvasively, provides valuable information for the study of cardiac arrhythmias. In this chapter, novel cardiac signal analysis techniques that allow the study and diagnosis of cardiac arrhythmias are described, with emphasis on cardiac mapping which allows for spatiotemporal analysis of cardiac signals.Cardiac mapping can serve as a diagnostic tool by recording cardiac signals either in close contact to the heart tissue or noninvasively from the body surface, and allows the identification of cardiac sites responsible of the development or maintenance of arrhythmias. Cardiac mapping can also be used for research in cardiac arrhythmias in order to understand their mechanisms. For this purpose, both synthetic signals generated by computer simulations and animal experimental models allow for more controlled physiological conditions and complete access to the organ.

  8. Systems biology and cardiac arrhythmias.

    PubMed

    Grace, Andrew A; Roden, Dan M

    2012-10-27

    During the past few years, the development of effective, empirical technologies for treatment of cardiac arrhythmias has exceeded the pace at which detailed knowledge of the underlying biology has accumulated. As a result, although some clinical arrhythmias can be cured with techniques such as catheter ablation, drug treatment and prediction of the risk of sudden death remain fairly primitive. The identification of key candidate genes for monogenic arrhythmia syndromes shows that to bring basic biology to the clinic is a powerful approach. Increasingly sophisticated experimental models and methods of measurement, including stem cell-based models of human cardiac arrhythmias, are being deployed to study how perturbations in several biologic pathways can result in an arrhythmia-prone heart. The biology of arrhythmia is largely quantifiable, which allows for systematic analysis that could transform treatment strategies that are often still empirical into management based on molecular evidence.

  9. Chaos control of cardiac arrhythmias.

    PubMed

    Garfinkel, A; Weiss, J N; Ditto, W L; Spano, M L

    1995-01-01

    Chaos theory has shown that many disordered and erratic phenomena are in fact deterministic, and can be understood causally and controlled. The prospect that cardiac arrhythmias might be instances of deterministic chaos is therefore intriguing. We used a recently developed method of chaos control to stabilize a ouabain-induced arrhythmia in rabbit ventricular tissue in vitro. Extension of these results to clinically significant arrhythmias such as fibrillation will require overcoming the additional obstacles of spatiotemporal complexity.

  10. [Maternal cardiac arrhythmias in pregnancy].

    PubMed

    Facchini, M; Bauersfeld, U; Fasnacht, M; Candinas, R

    2000-12-23

    During pregnancy an increased incidence of maternal cardiac arrhythmias is observed. These include a wide spectrum, from clinically irrelevant isolated premature beats to debilitating supraventricular and ventricular tachycardias. In principle, management of arrhythmias during pregnancy is similar to that in non-pregnant patients. However, special consideration should be given to foetal age and potential teratogenic and haemodynamic adverse drug effects on the foetus. Therapeutic strategy should be guided by interdisciplinary consulting (i.e. cardiology, obstetrics, neonatology). Diagnostic evaluation must rule out underlying cardiovascular, pulmonary, endocrine or metabolic diseases. Additionally, precipitating factors such as excessive caffeine and/or alcohol ingestion and cigarette smoking should be avoided. For benign arrhythmias a conservative approach is appropriate. Antiarrhythmic drug selection depends on the specific arrhythmia being treated and the cardiac condition of the mother and the foetus. Some antiarrhythmic agents, such as propranolol, metoprolol, digoxin and quinidine, have been extensively tested during pregnancy and have proven to be safe; they should therefore, whenever possible, be used as firstline. For supraventricular tachycardia, intravenous adenosine may be used to terminate the arrhythmia if vagal manoeuvres fail. In emergency situations cardioversion may be performed with relative safety. Implantable cardioverter defibrillators as a preventive measure for life-threatening arrhythmias in pregnant patients do not seem to increase the risk of major complications.

  11. Cardiac arrhythmias in paediatric practice.

    PubMed

    Chan, K Y; Loke, K Y; Yip, W C; Tay, J S

    1989-01-01

    Clinical data of patients with cardiac arrhythmias managed between May 1986 and March 1988 were reviewed to determine their mode of presentation and clinical course. Of the 5,768 admissions, 62 (1.07%) patients had arrhythmias. During the same period, 21 patients were managed as outpatients with 13 being new referrals. Thirty-eight patients had undergone corrective cardiac procedures, 8 others had congenital heart lesions, 3 were associated with acquired cardiac pathology and the remaining had isolated arrhythmias. The cardiac arrhythmias were: right bundle branch block 36, premature atrial and ventricular contractions 15, supraventricular tachycardia (SVT) 15, atrioventricular (AV) block 7, sinus bradycardia 3, atrial fibrillation 2, ventricular tachycardia and fibrillation 2, Wolff-Parkinson-White syndrome without SVT 2, bradytachyarrhythmia 1. There were 3 patients with foetal SVT, one persisting till day 1. High grade AV block occurred in 2 patients post-surgically and needed pacing. Only 2 others were symptomatic. Other than the 38 patients who underwent corrective procedures (2 had balloon valvuloplasty for pulmonary stenosis), 8 others had structural heart disease. There was 1 sudden death and 5 died from their primary heart disease.

  12. Cardiac Arrhythmias: Diagnosis, Symptoms, and Treatments.

    PubMed

    Fu, Du-Guan

    2015-11-01

    The cardiac arrhythmia is characterized by irregular rhythm of heartbeat which could be either too slow (<60 beats/min) or too fast (>100 beats/min) and can happen at any age. The use of pacemaker and defibrillators devices has been suggested for heart arrhythmias patients. The antiarrhythmic medications have been reported for the treatment of cardiac arrhythmias or irregular heartbeats. The diagnosis, symptoms, and treatments of cardiac arrhythmias as well as the radiofrequency ablation, tachycardia, Brugada syndrome, arterial fibrillation, and recent research on the genetics of cardiac arrhythmias have been described here.

  13. Common cardiac arrhythmias: recognition and treatment.

    PubMed

    Talmers, F N; Kinhal, V; Sabharwal, S; Weissler, A M

    1981-04-01

    Cardiac arrhythmias are commonly seen in the everyday practice of medicine by the physician. Although certain arrhythmias may be suspected clinically, precise diagnosis is made by electrocardiographic recording of the abnormal rhythm. Once the arrhythmia has been recorded, the next steps are proper electrocardiographic diagnosis and selection of proper treatment. The specific mode of therapy and the speed with which it is delivered will depend not only on the type of arrhythmia, but also on the hemodynamic consequences of the rhythm abnormality on the patient's cardiovascular system. The purpose of this paper is to discuss the electrocardiographic criteria of common cardiac arrhythmias as well as current concepts regarding therapy.

  14. Evaluation and Management of Maternal Cardiac Arrhythmias.

    PubMed

    Metz, Torri D; Khanna, Amber

    2016-12-01

    Pregnant women often complain of palpitations. The differential diagnosis for new-onset palpitations in pregnancy ranges from benign conditions to life-threatening arrhythmias. Maternal arrhythmias can occur in isolation or in the setting of underlying structural heart disease. Optimal management of maternal cardiac arrhythmias includes identification of the specific arrhythmia, diagnosis of comorbid conditions, and appropriate intervention. In general, management of maternal cardiac arrhythmias is similar to that of the general population. Special consideration must be given as to the effects of medications and procedures on both the mother and fetus to optimize outcomes. The importance of multidisciplinary care with cardiology, obstetrics, and anesthesia is emphasized.

  15. Update in cardiac arrhythmias and pacing.

    PubMed

    García-Bolao, Ignacio; Ruiz-Mateas, Francisco; Bazan, Victor; Berruezo, Antonio; Alcalde, Oscar; Leal del Ojo, Juan; Acosta, Juan; Martínez Sellés, Manuel; Mosquera, Ignacio

    2015-03-01

    This article discusses the main advances in cardiac arrhythmias and pacing published between 2013 and 2014. Special attention is given to the interventional treatment of atrial fibrillation and ventricular arrhythmias, and on advances in cardiac pacing and implantable cardioverter defibrillators, with particular reference to the elderly patient.

  16. Update on arrhythmias and cardiac pacing 2013.

    PubMed

    Almendral, Jesús; Pombo, Marta; Martínez-Alday, Jesús; González-Rebollo, José M; Rodríguez-Font, Enrique; Martínez-Ferrer, José; Castellanos, Eduardo; García-Fernández, F Javier; Ruiz-Mateas, Francisco

    2014-04-01

    This report discusses a selection of the most relevant articles on cardiac arrhythmias and pacing published in 2013. The first section discusses arrhythmias, classified as regular paroxysmal supraventricular tachyarrhythmias, atrial fibrillation, and ventricular arrhythmias, together with their treatment by means of an implantable cardioverter defibrillator. The next section reviews cardiac pacing, subdivided into resynchronization therapy, remote monitoring of implantable devices, and pacemakers. The final section discusses syncope.

  17. Inherited arrhythmias: The cardiac channelopathies

    PubMed Central

    Behere, Shashank P; Weindling, Steven N

    2015-01-01

    Ion channels in the myocardial cellular membrane are responsible for allowing the cardiac action potential. Genetic abnormalities in these channels can predispose to life-threatening arrhythmias. We discuss the basic science of the cardiac action potential; outline the different clinical entities, including information regarding overlapping diagnoses, touching upon relevant genetics, new innovations in screening, diagnosis, risk stratification, and management. The special considerations of sudden unexplained death and sudden infant death syndrome are discussed. Scientists and clinicians continue to reconcile the rapidly growing body of knowledge regarding the molecular mechanisms and genetics while continuing to improve our understanding of the various clinical entities and their diagnosis and management in clinical setting. Two separate searches were run on the National Center for Biotechnology Information's website. The first using the term cardiac channelopathies was run on the PubMed database using filters for time (published in past 5 years) and age (birth-18 years), yielding 47 results. The second search using the medical subject headings (MeSH) database with the search terms “Long QT Syndrome” (MeSH) and “Short QT Syndrome” (MeSH) and “Brugada Syndrome” (MeSH) and “Catecholaminergic Polymorphic Ventricular Tachycardia” (MeSH), applying the same filters yielded 467 results. The abstracts of these articles were studied, and the articles were categorized and organized. Articles of relevance were read in full. As and where applicable, relevant references and citations from the primary articles where further explored and read in full. PMID:26556967

  18. Behavioral influences on cardiac arrhythmias.

    PubMed

    Lampert, Rachel

    2016-01-01

    Stress can trigger both ventricular and atrial arrhythmias, as evidenced by epidemiological, clinical, and laboratory studies, through its impact on autonomic activity. Chronic stress also increases vulnerability to arrhythmias. Novel therapies aimed at decreasing the psychological and physiological response to stress may decrease arrhythmia frequency and improve quality of life.

  19. Evaluation of Cardiac Arrhythmia among Athletes

    PubMed Central

    Walker, James; Calkins, Hugh; Nazarian, Saman

    2010-01-01

    Due to the growing awareness of exercise related arrhythmias and improved sensitivity of diagnostic modalities, physicians are increasingly faced with choices that may have life changing impact for the athlete. This article surveys recent research and expert opinion addressing benign and pathogenic cardiac changes underlying arrhythmias in athletes. PMID:20870195

  20. Microwave Treatment for Cardiac Arrhythmias

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey (Inventor); Carl, James R. (Inventor); Raffoul, George W. (Inventor); Pacifico, Antonio (Inventor)

    1999-01-01

    Method and apparatus are provided for propagating microwave energy into heart tissues to produce a desired temperature profile therein at tissue depths sufficient for thermally ablating arrhythmogenic cardiac tissue to treat ventricular tachycardia and other arrhythmias while preventing excessive heating of surrounding tissues, organs, and blood. A wide bandwidth double-disk antenna is effective for this purpose over a bandwidth of about six gigahertz. A computer simulation provides initial screening capabilities for an antenna such as antenna, frequency, power level, and power application duration. The simulation also allows optimization of techniques for specific patients or conditions. In operation, microwave energy between about 1 Gigahertz and 12 Gigahertz is applied to monopole microwave radiator having a surface wave limiter. A test setup provides physical testing of microwave radiators to determine the temperature profile created in actual heart tissue or ersatz heart tissue. Saline solution pumped over the heart tissue with a peristaltic pump simulates blood flow. Optical temperature sensors disposed at various tissue depths within the heart tissue detect the temperature profile without creating any electromagnetic interference. The method may be used to produce a desired temperature profile in other body tissues reachable by catheter such as tumors and the like.

  1. Cardiac arrhythmias during or after epileptic seizures.

    PubMed

    van der Lende, Marije; Surges, Rainer; Sander, Josemir W; Thijs, Roland D

    2016-01-01

    Seizure-related cardiac arrhythmias are frequently reported and have been implicated as potential pathomechanisms of Sudden Unexpected Death in Epilepsy (SUDEP). We attempted to identify clinical profiles associated with various (post)ictal cardiac arrhythmias. We conducted a systematic search from the first date available to July 2013 on the combination of two terms: 'cardiac arrhythmias' and 'epilepsy'. The databases searched were PubMed, Embase (OVID version), Web of Science and COCHRANE Library. We attempted to identify all case reports and case series. We identified seven distinct patterns of (post)ictal cardiac arrhythmias: ictal asystole (103 cases), postictal asystole (13 cases), ictal bradycardia (25 cases), ictal atrioventricular (AV)-conduction block (11 cases), postictal AV-conduction block (2 cases), (post)ictal atrial flutter/atrial fibrillation (14 cases) and postictal ventricular fibrillation (3 cases). Ictal asystole had a mean prevalence of 0.318% (95% CI 0.316% to 0.320%) in people with refractory epilepsy who underwent video-EEG monitoring. Ictal asystole, bradycardia and AV-conduction block were self-limiting in all but one of the cases and seen during focal dyscognitive seizures. Seizure onset was mostly temporal (91%) without consistent lateralisation. Postictal arrhythmias were mostly found following convulsive seizures and often associated with (near) SUDEP. The contrasting clinical profiles of ictal and postictal arrhythmias suggest different pathomechanisms. Postictal rather than ictal arrhythmias seem of greater importance to the pathophysiology of SUDEP.

  2. Cardiac arrhythmias during or after epileptic seizures

    PubMed Central

    van der Lende, Marije; Surges, Rainer; Sander, Josemir W; Thijs, Roland D

    2016-01-01

    Seizure-related cardiac arrhythmias are frequently reported and have been implicated as potential pathomechanisms of Sudden Unexpected Death in Epilepsy (SUDEP). We attempted to identify clinical profiles associated with various (post)ictal cardiac arrhythmias. We conducted a systematic search from the first date available to July 2013 on the combination of two terms: ‘cardiac arrhythmias’ and ‘epilepsy’. The databases searched were PubMed, Embase (OVID version), Web of Science and COCHRANE Library. We attempted to identify all case reports and case series. We identified seven distinct patterns of (post)ictal cardiac arrhythmias: ictal asystole (103 cases), postictal asystole (13 cases), ictal bradycardia (25 cases), ictal atrioventricular (AV)-conduction block (11 cases), postictal AV-conduction block (2 cases), (post)ictal atrial flutter/atrial fibrillation (14 cases) and postictal ventricular fibrillation (3 cases). Ictal asystole had a mean prevalence of 0.318% (95% CI 0.316% to 0.320%) in people with refractory epilepsy who underwent video-EEG monitoring. Ictal asystole, bradycardia and AV-conduction block were self-limiting in all but one of the cases and seen during focal dyscognitive seizures. Seizure onset was mostly temporal (91%) without consistent lateralisation. Postictal arrhythmias were mostly found following convulsive seizures and often associated with (near) SUDEP. The contrasting clinical profiles of ictal and postictal arrhythmias suggest different pathomechanisms. Postictal rather than ictal arrhythmias seem of greater importance to the pathophysiology of SUDEP. PMID:26038597

  3. Early afterdepolarizations and cardiac arrhythmias.

    PubMed

    Weiss, James N; Garfinkel, Alan; Karagueuzian, Hrayr S; Chen, Peng-Sheng; Qu, Zhilin

    2010-12-01

    Early afterdepolarizations (EADs) are an important cause of lethal ventricular arrhythmias in long QT syndromes and heart failure, but the mechanisms by which EADs at the cellular scale cause arrhythmias such as polymorphic ventricular tachycardia (PVT) and torsades de pointes (TdP) at the tissue scale are not well understood. Here we summarize recent progress in this area, discussing (1) the ionic basis of EADs, (2) evidence that deterministic chaos underlies the irregular behavior of EADs, (3) mechanisms by which chaotic EADs synchronize in large numbers of coupled cells in tissue to overcome source-sink mismatches, (4) how this synchronization process allows EADs to initiate triggers and generate mixed focal reentrant ventricular arrhythmias underlying PVT and TdP, and (5) therapeutic implications.

  4. Ranolazine Therapy in Cardiac Arrhythmias.

    PubMed

    Pulford, Brian R; Kluger, Jeffrey

    2016-09-01

    Ranolazine is an antianginal medication originally granted approval by the U.S. Food and Drug Administration for therapeutic use in 2006. Since its introduction into the U.S. market, there have been multiple trials and clinical case reports that demonstrate ranolazine may be effective in the prevention and treatment of both atrial and ventricular arrhythmias, including postoperative atrial fibrillation following coronary artery bypass graft (CABG) surgery. More recently, the combination of dronedarone with ranolazine has demonstrated in initial studies to have a synergistic effect in the reduction of burden of atrial fibrillation. This article will review the basic pharmacology of ranolazine, the studies demonstrating use of ranolazine in atrial and ventricular arrhythmias, the limitations to the use of ranolazine as antiarrhythmic therapy, and explore the synergistic effect with other agents in the suppression of arrhythmias.

  5. Gene therapy to treat cardiac arrhythmias.

    PubMed

    Bongianino, Rossana; Priori, Silvia G

    2015-09-01

    Gene therapy to treat electrical dysfunction of the heart is an appealing strategy because of the limited therapeutic options available to manage the most-severe cardiac arrhythmias, such as ventricular tachycardia, ventricular fibrillation, and asystole. However, cardiac genetic manipulation is challenging, given the complex mechanisms underlying arrhythmias. Nevertheless, the growing understanding of the molecular basis of these diseases, and the development of sophisticated vectors and delivery strategies, are providing researchers with adequate means to target specific genes and pathways involved in disorders of heart rhythm. Data from preclinical studies have demonstrated that gene therapy can be successfully used to modify the arrhythmogenic substrate and prevent life-threatening arrhythmias. Therefore, gene therapy might plausibly become a treatment option for patients with difficult-to-manage acquired arrhythmias and for those with inherited arrhythmias. In this Review, we summarize the preclinical studies into gene therapy for acquired and inherited arrhythmias of the atria or ventricles. We also provide an overview of the technical advances in the design of constructs and viral vectors to increase the efficiency and safety of gene therapy and to improve selective delivery to target organs.

  6. Effect of female sex on cardiac arrhythmias.

    PubMed

    Gowd, B M Pampana; Thompson, Paul D

    2012-01-01

    We performed a systematic literature review to examine the effect of female sex on cardiac electrophysiology and arrhythmias. Women have faster resting heart rates yet longer QTc intervals. Women also have shorter PR and QRS intervals; these are presumed to be due to the small heart size of women and hormonal effects on ion channels. Women are two times more likely to experience atrioventricular nodal re-entry tachycardia than men. In contrast to atrioventricular nodal re-entry tachycardia, accessory-pathway-mediated atrial arrhythmias are less common in women, and women have more concealed and fewer manifest accessory pathways. Supraventricular tachycardia in women varies with the menstrual cycle and is more frequent in the luteal phase and inversely correlated with estrogen levels. Atrial fibrillation (AF) is less prevalent in women, but the absolute number of women with AF is higher because AF prevalence increases with age and women live longer. Also, complications of AF are greater in women. Women are generally less prone to ventricular arrhythmias, but they comprise a higher percentage of symptomatic subjects with congenital long QT syndrome and are more often affected by drugs that prolong the QT. Women are less prone to arrhythmias during pregnancy although they commonly complain of palpitations, which are sometimes related to the increase in heart rate during pregnancy. Clinicians should explore the relationship of arrhythmias to the menstrual cycle in female patients and should know that the menstrual cycle may affect the induction of arrhythmias during electrophysiological testing. Clinicians should also be aware that the arrhythmia and the result of clinical trials examining arrhythmia treatment may have different implications in women than in men.

  7. Sarcolemmal KATP channel modulators and cardiac arrhythmias.

    PubMed

    Baczkó, I; Husti, Z; Lang, V; Leprán, I; Light, P E

    2011-01-01

    Cardiac atrial and ventricular arrhythmias are major causes of mortality and morbidity. Ischemic heart disease is the most common cause underlying 1) the development of ventricular fibrillation that results in sudden cardiac death and 2) atrial fibrillation that can lead to heart failure and stroke. Current pharmacological agents for the treatment of ventricular and atrial arrhythmias exhibit limited effectiveness and many of these agents can cause serious adverse effects - including the provocation of lethal ventricular arrhythmias. Sarcolemmal ATP-sensitive potassium channels (sarcK(ATP)) couple cellular metabolism to membrane excitability in a wide range of tissues. In the heart, sarcK(ATP) are activated during metabolic stress including myocardial ischemia, and both the opening of sarcK(ATP) and mitochondrial K(ATP) channels protect the ischemic myocardium via distinct mechanisms. Myocardial ischemia leads to a series of events that promote the generation of arrhythmia substrate eventually resulting in the development of life-threatening arrhythmias. In this review, the possible mechanisms of the anti- and proarrhythmic effects of sarcK(ATP) modulation as well as the influence of pharmacological K(ATP) modulators are discussed. It is concluded that in spite of the significant advances made in this field, the possible cardiovascular therapeutic utility of current sarcK(ATP) channel modulators is still hampered by the lack of chamber-specific selectivity. However, recent insights into the chamber-specific differences in the molecular composition of sarcKATP in addition to already existing cardioselective sarcK(ATP) channel modulators with sarcK(ATP) isoform selectivity holds the promise for the future development of pharmacological strategies specific for a variety of atrial and ventricular arrhythmias.

  8. Bifurcation theory and cardiac arrhythmias

    PubMed Central

    Karagueuzian, Hrayr S; Stepanyan, Hayk; Mandel, William J

    2013-01-01

    In this paper we review two types of dynamic behaviors defined by the bifurcation theory that are found to be particularly useful in describing two forms of cardiac electrical instabilities that are of considerable importance in cardiac arrhythmogenesis. The first is action potential duration (APD) alternans with an underlying dynamics consistent with the period doubling bifurcation theory. This form of electrical instability could lead to spatially discordant APD alternans leading to wavebreak and reentrant form of tachyarrhythmias. Factors that modulate the APD alternans are discussed. The second form of bifurcation of importance to cardiac arrhythmogenesis is the Hopf-homoclinic bifurcation that adequately describes the dynamics of the onset of early afterdepolarization (EAD)-mediated triggered activity (Hopf) that may cause ventricular tachycardia and ventricular fibrillation (VT/VF respectively). The self-termination of the triggered activity is compatible with the homoclinic bifurcation. Ionic and intracellular calcium dynamics underlying these dynamics are discussed using available experimental and simulation data. The dynamic analysis provides novel insights into the mechanisms of VT/VF, a major cause of sudden cardiac death in the US. PMID:23459417

  9. Pharmacotherapy of cardiac arrhythmias--basic science for clinicians.

    PubMed

    Shu, Juan; Zhou, Jun; Patel, Chinmay; Yan, Gan-Xin

    2009-11-01

    Cardiac arrhythmias occur in approximately 5.3% of the population and contribute substantially to morbidity and mortality. Pharmacological therapy still remains the major approach in management of patients with nearly every form of cardiac arrhythmia. Effective and safe management of cardiac arrhythmias with antiarrhythmic drugs requires understanding of basic mechanisms for various cardiac arrhythmias, clinical diagnosis of an arrhythmia and identification of underlying cardiac diseases, pharmacokinetics, and antiarrhythmic properties of each individual antiarrhythmic drug. Most cardiac arrhythmias occur via one of the two mechanisms: abnormal impulse formation and reentry or both. Antiarrhythmic drugs primarily work via influencing cardiac automaticity or triggered activity or by their effects on effective refractoriness of cardiac cells. Proarrhythmic effects of antiarrhythmic drugs are also briefly discussed in this review article.

  10. Cardiac Arrhythmias and Abnormal Electrocardiograms After Acute Stroke.

    PubMed

    Ruthirago, Doungporn; Julayanont, Parunyou; Tantrachoti, Pakpoom; Kim, Jongyeol; Nugent, Kenneth

    2016-01-01

    Cardiac arrhythmias and electrocardiogram (ECG) abnormalities occur frequently but are often underrecognized after strokes. Acute ischemic and hemorrhagic strokes in some particular area of brain can disrupt central autonomic control of the heart, precipitating cardiac arrhythmias, ECG abnormalities, myocardial injury and sometimes sudden death. Identification of high-risk patients after acute stroke is important to arrange appropriate cardiac monitoring and effective management of arrhythmias, and to prevent cardiac morbidity and mortality. More studies are needed to better clarify pathogenesis, localization of areas associated with arrhythmias and practical management of arrhythmias and abnormal ECGs after acute stroke.

  11. Non-invasive Mapping of Cardiac Arrhythmias.

    PubMed

    Shah, Ashok; Hocini, Meleze; Haissaguerre, Michel; Jaïs, Pierre

    2015-08-01

    Since more than 100 years, 12-lead electrocardiography (ECG) is the standard-of-care tool, which involves measuring electrical potentials from limited sites on the body surface to diagnose cardiac disorder, its possible mechanism, and the likely site of origin. Several decades of research has led to the development of a 252-lead ECG and computed tomography (CT) scan-based three-dimensional electro-imaging modality to non-invasively map abnormal cardiac rhythms including fibrillation. These maps provide guidance towards ablative therapy and thereby help advance the management of complex heart rhythm disorders. Here, we describe the clinical experience obtained using non-invasive technique in mapping the electrical disorder and guide the catheter ablation of atrial arrhythmias (premature atrial beat, atrial tachycardia, atrial fibrillation), ventricular arrhythmias (premature ventricular beats), and ventricular pre-excitation (Wolff-Parkinson-White syndrome).

  12. Heart-brain interactions in cardiac arrhythmia.

    PubMed

    Taggart, P; Critchley, H; Lambiase, P D

    2011-05-01

    This review examines current knowledge of the effects of higher brain centres and autonomic control loops on the heart with particular relevance to arrhythmogenesis. There is now substantial evidence that higher brain function (cortex), the brain stem and autonomic nerves affect cardiac electrophysiology and arrhythmia, and that these may function as an interactive system. The roles of mental stress and emotion in arrhythmogenesis and sudden cardiac death are no longer confined to the realms of anecdote. Advances in molecular cardiology have identified cardiac cellular ion channel mutations conferring vulnerability to arrhythmic death at the myocardial level. Indeed, specific channelopathies such as long QT syndrome and Brugada syndrome are selectively sensitive to either sympathetic or vagal stimulation. There is increasing evidence that afferent feedback from the heart to the higher centres may affect efferent input to the heart and modulate the cardiac electrophysiology. The new era of functional neuroimaging has identified the central neural circuitry in this brain-heart axis. Since precipitants of sudden fatal arrhythmia are frequently environmental and behavioural, central pathways translating stress into autonomic effects on the heart might be considered as therapeutic targets. These brain-heart interactions help explain the apparent randomness of sudden cardiac events and provide new insights into future novel therapies to prevent sudden death.

  13. Almanac 2013: cardiac arrhythmias and pacing.

    PubMed

    Liew, Reginald

    2013-10-01

    Important advances have been made in the past few years in the fields of clinical cardiac electrophysiology and pacing. Researchers and clinicians have a greater understanding of the pathophysiological mechanisms underlying atrial fibrillation (AF), which has transpired into improved methods of detection, risk stratification, and treatments. The introduction of novel oral anticoagulants has provided clinicians with alternative options in managing patients with AF at moderate to high thromboembolic risk and further data has been emerging on the use of catheter ablation for the treatment of symptomatic AF. Another area of intense research in the field of cardiac arrhythmias and pacing is in the use of cardiac resynchronisation therapy (CRT) for the treatment of patients with heart failure. Following the publication of major landmark randomised controlled trials reporting that CRT confers a survival advantage in patients with severe heart failure and improves symptoms, many subsequent studies have been performed to further refine the selection of patients for CRT and determine the clinical characteristics associated with a favourable response. The field of sudden cardiac death and implantable cardioverter defibrillators also continues to be actively researched, with important new epidemiological and clinical data emerging on improved methods for patient selection, risk stratification, and management. This review covers the major recent advances in these areas related to cardiac arrhythmias and pacing.

  14. Fractals analysis of cardiac arrhythmias.

    PubMed

    Saeed, Mohammed

    2005-09-06

    Heart rhythms are generated by complex self-regulating systems governed by the laws of chaos. Consequently, heart rhythms have fractal organization, characterized by self-similar dynamics with long-range order operating over multiple time scales. This allows for the self-organization and adaptability of heart rhythms under stress. Breakdown of this fractal organization into excessive order or uncorrelated randomness leads to a less-adaptable system, characteristic of aging and disease. With the tools of nonlinear dynamics, this fractal breakdown can be quantified with potential applications to diagnostic and prognostic clinical assessment. In this paper, I review the methodologies for fractal analysis of cardiac rhythms and the current literature on their applications in the clinical context. A brief overview of the basic mathematics of fractals is also included. Furthermore, I illustrate the usefulness of these powerful tools to clinical medicine by describing a novel noninvasive technique to monitor drug therapy in atrial fibrillation.

  15. Cancer chemotherapy and cardiac arrhythmias: a review.

    PubMed

    Tamargo, Juan; Caballero, Ricardo; Delpón, Eva

    2015-02-01

    Cardiovascular toxicity is a potential complication of cancer chemotherapy (CC) that increases the morbidity and mortality of cancer patients. Cardiac arrhythmias have been reported as an adverse effect of many chemotherapeutic drugs, including novel targeted therapies. The relationship between chemotherapy and arrhythmias has not been well-established and the proarrhythmogenic mechanisms remain uncertain as they can be the result of a direct electrophysiological effect or of changes in cardiac structure and function, including myocardial ischaemia and heart failure, which create an arrhythmogenic substrate. In this review we summarise available evidence of proarrhythmia induced by CC, discuss the possible mechanisms involved in this adverse effect and emphasise the importance of cardiac monitoring for the early diagnosis, intervention and surveillance of those patients more susceptible to develop proarrhythmia in an attempt to reduce the morbidity and mortality. Oncologists should be fully aware of proarrhythmia and the close collaboration between cardiologists and oncologists would result in a better cardiovascular assessment, risk stratification, cardiac monitoring and treatment during CC and during the follow-up. The final objective is to understand the mechanisms of proarrhythmia and evaluate its real incidence and clinical relevance so as to select the safest and most effective treatment for cancer patients.

  16. Microwave Treatment for Cardiac Arrhythmias

    NASA Technical Reports Server (NTRS)

    Hernandez-Moya, Sonia

    2009-01-01

    NASA seeks to transfer the NASA developed microwave ablation technology, designed for the treatment of ventricular tachycardia (irregular heart beat), to industry. After a heart attack, many cells surrounding the resulting scar continue to live but are abnormal electrically; they may conduct impulses unusually slowly or fire when they would typically be silent. These diseased areas might disturb smooth signaling by forming a reentrant circuit in the muscle. The objective of microwave ablation is to heat and kill these diseased cells to restore appropriate electrical activity in the heart. This technology is a method and apparatus that provides for propagating microwave energy into heart tissues to produce a desired temperature profile therein at tissue depths sufficient for thermally ablating arrhythmogenic cardiac tissue while preventing excessive heating of surrounding tissues, organs, and blood. A wide bandwidth double-disk antenna is effective for this purpose over a bandwidth of about six gigahertz. A computer simulation provides initial screening capabilities for an antenna such as antenna, frequency, power level, and power application duration. The simulation also allows optimization of techniques for specific patients or conditions. In comparison with other methods that involve direct-current pulses or radio frequencies below 1 GHz, this method may prove more effective in treating ventricular tachycardia. This is because the present method provides for greater control of the location, cross-sectional area, and depth of a lesion via selection of the location and design of the antenna and the choice of microwave power and frequency.

  17. Acute emotional stress and cardiac arrhythmias.

    PubMed

    Ziegelstein, Roy C

    2007-07-18

    Episodes of acute emotional stress can have significant adverse effects on the heart. Acute emotional stress can produce left ventricular contractile dysfunction, myocardial ischemia, or disturbances of cardiac rhythm. Although these abnormalities are often only transient, their consequences can be gravely damaging and sometimes fatal. Despite the many descriptions of catastrophic cardiovascular events in the setting of acute emotional stress, the anatomical substrate and physiological pathways by which emotional stress triggers cardiovascular events are only now being characterized, aided by the advent of functional neuroimaging. Recent evidence indicates that asymmetric brain activity is particularly important in making the heart more susceptible to ventricular arrhythmias. Lateralization of cerebral activity during emotional stress may stimulate the heart asymmetrically and produce areas of inhomogeneous repolarization that create electrical instability and facilitate the development of cardiac arrhythmias. Patients with ischemic heart disease who survive an episode of sudden cardiac death in the setting of acute emotional stress should receive a beta-blocker. Nonpharmacological approaches to manage emotional stress in patients with and without coronary artery disease, including social support, relaxation therapy, yoga, meditation, controlled slow breathing, and biofeedback, are also appropriate to consider and merit additional investigation in randomized trials.

  18. Mechanistic and therapeutic perspectives for cardiac arrhythmias: beyond ion channels.

    PubMed

    Wu, Yufei; Li, Jun; Xu, Liang; Lin, Li; Chen, Yi-Han

    2017-03-24

    Cardiac arrhythmias are among the most common causes of death in the world. Foundational studies established the critical role of ion channel disorders in arrhythmias, yet defects in ion channels themselves, such as mutations, may not account for all arrhythmias. Despite the progress made in recent decades, the antiarrhythmic drugs currently available have limited effectiveness, and the majority of these drugs can have proarrhythmic effects. This review describes novel knowledge on cellular mechanisms that cause cardiac arrhythmias, focuses on the dysfunction of subcellular organelles and intracellular logistics, and discusses potential strategies and challenges for developing novel, safe and effective treatments for arrhythmias.

  19. Cardiac arrhythmias in Chagas' heart disease.

    PubMed

    Elizari, M V; Chiale, P A

    1993-10-01

    Chagas' disease is a chronic parasitosis affecting most Latin American countries. Its most important clinical manifestation is a late developing chronic myocarditis and, much less frequently, an early acute myocarditis. Chagasic myocardial damage is microfocal and disseminated throughout the heart. In most cases, the coexistence of areas of myocytic degeneration, inflammatory infiltration, and fibrosis suggests a permanent evolving process. Commonly, chronic chagasic myocarditis resembles a dilated cardiomyopathy, with characteristic ECG abnormalities (atrial and ventricular extrasystoles, intraventricular and/or AV conduction disturbances, and primary ST-T wave changes). Since myocardial damage is scattered throughout the heart, the ECG abnormalities (arrhythmias, conduction disturbances, and repolarization changes) are also representative of the widespread cardiac involvement. Thus, sick sinus syndrome, atrial extrasystoles, intraatrial conduction disturbances, and atrial fibrillation or flutter are common findings in different stages of the disease. At the ventricular level, both conduction disturbances and arrhythmias are conspicuous expressions of the myocardial damage. Right bundle branch block alone or in combination with left anterior hemiblock are the most common conduction defects. Further compromise of the conduction system can lead to different degrees of AV block. Chagas' disease is the main cause of bundle branch block and AV block in endemic areas. In advanced cases of Chagas' heart disease, ventricular premature contractions are extremely frequent, multiform, and repetitive (couplets and runs of ventricular tachycardia), and show R on T phenomenon. These arrhythmias are usually aggravated by increased sympathetic tone, implying an enhanced risk of cardiac sudden death among chagasic patients, which is sometimes the first manifestation of the illness. Chronic chagasic myocarditis is the leading cause of cardiovascular death, mostly as a consequence

  20. Basic Cardiac Electrophysiology and Common Drug-induced Arrhythmias.

    PubMed

    Lee, Aimee; Pickham, David

    2016-09-01

    Drugs can be a double-edged sword, providing the benefit of symptom alleviation and disease modification but potentially causing harm from adverse cardiac arrhythmic events. Proarrhythmia is the ability of a drug to cause an arrhythmia, the number one reason for drugs to be withdrawn from the patient. Drug-induced arrhythmias are defined as the production of de novo arrhythmias or aggravation of existing arrhythmias, as a result of previous or concomitant pharmacologic treatment. This review summarizes normal cardiac cell and tissue functioning and provides an overview of drugs that effect cardiac repolarization and the adverse effects of commonly administered antiarrhythmics.

  1. Neuroanatomical correlates of severe cardiac arrhythmias in acute ischemic stroke.

    PubMed

    Seifert, Frank; Kallmünzer, Bernd; Gutjahr, Isabell; Breuer, Lorenz; Winder, Klemens; Kaschka, Iris; Kloska, Stephan; Doerfler, Arnd; Hilz, Max-Josef; Schwab, Stefan; Köhrmann, Martin

    2015-05-01

    Neurocardiological interactions can cause severe cardiac arrhythmias in patients with acute ischemic stroke. The relationship between the lesion location in the brain and the occurrence of cardiac arrhythmias is still discussed controversially. The aim of the present study was to correlate the lesion location with the occurrence of cardiac arrhythmias in patients with acute ischemic stroke. Cardiac arrhythmias were systematically assessed in patients with acute ischemic stroke during the first 72 h after admission to a monitored stroke unit. Voxel-based lesion-symptom mapping (VLSM) was used to correlate the lesion location with the occurrence of clinically relevant severe arrhythmias. Overall 150 patients, 56 with right-hemispheric and 94 patients with a left-hemispheric lesion, were eligible to be included in the VLSM study. Severe cardiac arrhythmias were present in 49 of these 150 patients (32.7%). We found a significant association (FDR correction, q < 0.05) between lesions in the right insular, right frontal and right parietal cortex as well as the right amygdala, basal ganglia and thalamus and the occurrence of cardiac arrhythmias. Because left- and right-hemispheric lesions were analyzed separately, the significant findings rely on the 56 patients with right-hemispheric lesions. The data indicate that these areas are involved in central autonomic processing and that right-hemispheric lesions located to these areas are associated with an elevated risk for severe cardiac arrhythmias.

  2. Fetal Arrhythmias Associated with Cardiac Rhabdomyomas

    PubMed Central

    Wacker-Gussmann, Annette; Strasburger, Janette F; Cuneo, Bettina; Wiggins, Delonia; Gotteiner, Nina; Wakai, Ronald T

    2014-01-01

    Background Primary heart tumors in fetuses are rare and mainly represent rhabdomyomas. The tumors have a variable expression and can be associated with arrhythmias, including both wide and narrow QRS tachycardia. Although multiple Doppler techniques exist to assess fetal heart rhythm, it can be difficult to record precise electrophysiological pathologies in fetal life. Objective Investigations defining precise electrophysiological diagnosis were performed using fetal magnetocardiography (fMCG). Methods In addition to routine fetal echocardiography, fMCG was used to investigate electrophysiologic rhythm patterns in a series of 10 fetuses with cardiac rhabdomyomas. Results The mean gestational age of the fetuses was 28.6 weeks (SD ± 4.7 weeks). The multiple rhabdomyomas were mainly located in the right and left ventricles as well as around the AV groove. Arrhythmias or conduction abnormalities were diagnosed in all 10 patients, although only six of them were referred due to that indication. Remarkably, 80% (8/10) had associated Wolff-Parkinson-White pre-excitation. In addition, we found prominent p waves in four fetuses. Conclusion In fetuses with rhabdomyomas, a disease where rhythm pathology is common, precise electrophysiological diagnosis can now be made by fMCG. fMCG is complimentary to echocardiography for rhythm assessment, and can detect conduction abnormalities that are not possible to diagnose prenatally with M-mode or pulsed Doppler ultrasound. Risk factor assessment using fMCG can support pregnancy management and post-natal treatment and follow-up. PMID:24333285

  3. Ethanol for the treatment of cardiac arrhythmias

    PubMed Central

    Schurmann, Paul; Peñalver, Jorge; Valderrábano, Miguel

    2015-01-01

    Introduction Ethanol infusion was an early mode of ablative treatment for cardiac arrhythmias. Its initial descriptions involved coronary intra-arterial delivery, targeting arrhythmogenic substrates in drug-refractory ventricular tachycardia or the atrioventricular node. Largely superseded by radiofrequency ablation (RFA) and other contact-based technologies as a routine ablation strategy, intracoronary arterial ethanol infusion remains as an alternative option in the treatment of ventricular tachycardia when conventional ablation fails. Arrhythmic foci that are deep-seated in the myocardium may not be amenable to catheter ablation from either the endocardium or the epicardium by RFA, but they can be targeted by an ethanol infusion. Recent findings Recently, we have explored ethanol injection through cardiac venous systems, in order to avoid the risks of complications and limitations of coronary arterial instrumentation. Vein of Marshall ethanol infusion is being studied as an adjunctive procedure in ablation of atrial fibrillation, and coronary venous ethanol infusion for ventricular tachycardia. Conclusion Ethanol ablation remains useful as a bail-out technique for refractory cases to RFA, or as an adjunctive therapy that may improve the efficacy of catheter ablation procedures. PMID:26049378

  4. Cardiac arrhythmias induced by chloral hydrate in rhesus monkeys.

    PubMed

    Han, Pengfei; Song, Haibo; Yang, Pingliang; Xie, Huiqi; Kang, Y James

    2011-06-01

    Chloral hydrate has been long used as a safe sedative and hypnotic drug in humans. However, reports on its cardiovascular adverse effects have been published from time to time. The present study was undertaken to use Rhesus monkeys as a model to define the dose regiment of chloral hydrate at which cardiac arrhythmias can be induced and the consequences of the cardiac events. Male Rhesus monkeys of 2-3 years old were intravenously infused with chloral hydrate starting at 50 mg/kg with an increasing increment of 25 mg/kg until the occurrence of cardiac arrhythmias. In addition, a traditional up-and-down dosing procedure was applied to define a single dose level at which cardiac arrhythmias can be induced. The data obtained showed that when the sequentially escaladed dose reached 125 mg/kg, cardiac arrhythmias occurred in all monkeys tested. The single effective dose to cause cardiac arrhythmias calculated from the crossover analysis was 143 ± 4 mg/kg. This value would be equivalent to 68.6 ± 1.9 mg/kg for children and 46.4 ± 1.3 mg/kg for adults in humans. Under either multiple or single dose condition, cardiac arrhythmias did not occur before 40 min after the onset of anesthesia induced by chloral hydrate. Cardiac arrhythmias were recovered without help at the end of the anesthesia in most cases, but also continued after the regain of consciousness in some cases. The cardiac arrhythmias were accompanied with compromised cardiac function including suppressed fractional shortening and ejection fraction. This study thus suggests that cautions need to be taken when chloral hydrate is used above certain levels and beyond a certain period of anesthesia, and cardiac arrhythmias induced by chloral hydrate need to be closely monitored because compromised cardiac function may occur simultaneously. In addition, patients with cardiac arrhythmias induced by chloral hydrate should be monitored even after they are recovered from the anesthesia.

  5. Role of the autonomic nervous system in modulating cardiac arrhythmias.

    PubMed

    Shen, Mark J; Zipes, Douglas P

    2014-03-14

    The autonomic nervous system plays an important role in the modulation of cardiac electrophysiology and arrhythmogenesis. Decades of research has contributed to a better understanding of the anatomy and physiology of cardiac autonomic nervous system and provided evidence supporting the relationship of autonomic tone to clinically significant arrhythmias. The mechanisms by which autonomic activation is arrhythmogenic or antiarrhythmic are complex and different for specific arrhythmias. In atrial fibrillation, simultaneous sympathetic and parasympathetic activations are the most common trigger. In contrast, in ventricular fibrillation in the setting of cardiac ischemia, sympathetic activation is proarrhythmic, whereas parasympathetic activation is antiarrhythmic. In inherited arrhythmia syndromes, sympathetic stimulation precipitates ventricular tachyarrhythmias and sudden cardiac death except in Brugada and J-wave syndromes where it can prevent them. The identification of specific autonomic triggers in different arrhythmias has brought the idea of modulating autonomic activities for both preventing and treating these arrhythmias. This has been achieved by either neural ablation or stimulation. Neural modulation as a treatment for arrhythmias has been well established in certain diseases, such as long QT syndrome. However, in most other arrhythmia diseases, it is still an emerging modality and under investigation. Recent preliminary trials have yielded encouraging results. Further larger-scale clinical studies are necessary before widespread application can be recommended.

  6. Cardiac arrhythmias in recently diagnosed hypertensive patients at first presentation: an electrocardiographic-based study.

    PubMed

    Ejim, E C; Ike, S O; Anisiuba, B C; Essien, I O; Onwubere, B J; Ikeh, V O

    2012-01-01

    Various forms of cardiac arrhythmias have been documented in hypertensive subjects, and hypertension is an important risk factor for the development of atrial and ventricular arrhythmias and sudden death. Electrocardiography at rest easily documents significant arrhythmias in patients, and this study was carried out to determine the types and frequency of arrhythmias in hypertensive subjects at first presentation in the Hypertension Clinics of the University of Nigeria Teaching Hospital (UNTH) Enugu, Nigeria. The study was hospitalbased and retrospective in nature. The resting 12lead ECG reports of 346 consecutive hypertensive subjects seen at the Hypertension clinics of the UNTH Enugu over a 14 month period were retrieved from the case files and studied. Other information obtained from the case files included the age and gender of the subjects. The mean age of the subjects was 57.3 years. Ninety-five of the subjects had arrhythmias representing 27% of the study population, out of which fifty-five were males (57.9%) and forty were females (42.1%). However 26.9% of all the male subjects had arrhythmias while 28.2% of all the females had arrhythmias. Multiple ventricular ectopics, sinus tachycardia, sinus bradycardia and atrial fibrillation were the most prevalent arrhythmias. This study showed that a significant proportion of hypertensive subjects present initially with significant rhythm disturbances.

  7. Psychophysiological factors in ventricular arrhythmias and sudden cardiac death.

    PubMed

    Hatton, D C; Gilden, E R; Edwards, M E; Cutler, J; Kron, J; McAnulty, J H

    1989-01-01

    Plasma catecholamine levels were measured preceding programmed electrophysiological studies of patients who had survived a ventricular tachyarrhythmia episode. Psychological assessments of desire for control, locus of control and behavior pattern were obtained. Psychophysiological variables were analysed with respect to the severity of arrhythmias induced by the electrophysiological procedure. Analysis of data from 17 subjects showed desire for control was significantly higher in those with induced sustained arrhythmias than in those in which nonsustained arrhythmias were induced. No relationship was found between behavior pattern and arrhythmia severity or plasma catecholamine levels. There was a significant interaction between desire for control and behavior pattern with respect to epinephrine level. The findings indicate that psychological factors such as desire for control may be associated with potentially lethal arrhythmias and implicated in sudden cardiac death.

  8. Cardiac arrhythmias during exercise testing in healthy men.

    NASA Technical Reports Server (NTRS)

    Beard, E. F.; Owen, C. A.

    1973-01-01

    Clinically healthy male executives who participate in a long-term physical conditioning program have demonstrated cardiac arrhythmia during and after periodic ergometric testing at submaximal and maximal levels. In 1,385 tests on 248 subjects, it was found that 34% of subjects demonstrated an arrhythmia at some time and 13% of subjects developed arrhythmia on more than one test. Premature systoles of ventricular origin were most common, but premature systoles of atrial origin, premature systoles of junctional origin, paroxysmal atrial tachycardia, atrioventricular block, wandering pacemaker, and pre-excitation were also seen. Careful post-test monitoring and pulse rate regulated training sessions are suggested for such programs.

  9. Role of adipose tissue in the pathogenesis of cardiac arrhythmias.

    PubMed

    Samanta, Rahul; Pouliopoulos, Jim; Thiagalingam, Aravinda; Kovoor, Pramesh

    2016-01-01

    Epicardial adipose tissue is present in normal healthy individuals. It is a unique fat depot that, under physiologic conditions, plays a cardioprotective role. However, excess epicardial adipose tissue has been shown to be associated with prevalence and severity of atrial fibrillation. In arrhythmogenic right ventricular cardiomyopathy and myotonic dystrophy, fibrofatty infiltration of the myocardium is associated with ventricular arrhythmias. In the ovine model of ischemic cardiomyopathy, the presence of intramyocardial adipose or lipomatous metaplasia has been associated with increased propensity to ventricular tachycardia. These observations suggest a role of adipose tissue in the pathogenesis of cardiac arrhythmias. In this article, we review the role of cardiac adipose tissue in various cardiac arrhythmias and discuss the possible pathophysiologic mechanisms.

  10. Cardiac arrhythmias in hypokalemic periodic paralysis: Hypokalemia as only cause?

    PubMed

    Stunnenberg, Bas C; Deinum, Jaap; Links, Thera P; Wilde, Arthur A; Franssen, Hessel; Drost, Gea

    2014-09-01

    It is unknown how often cardiac arrhythmias occur in hypokalemic periodic paralysis (HypoPP) and if they are caused by hypokalemia alone or other factors. This systematic review shows that cardiac arrhythmias were reported in 27 HypoPP patients. Cases were confirmed genetically (13 with an R528H mutation in CACNA1S, 1 an R669H mutation in SCN4A) or had a convincing clinical diagnosis of HypoPP (13 genetically undetermined) if reported prior to the availability of genetic testing. Arrhythmias occurred during severe hypokalemia (11 patients), between attacks at normokalemia (4 patients), were treatment-dependent (2 patients), or unspecified (10 patients). Nine patients died from arrhythmia. Convincing evidence for a pro-arrhythmogenic factor other than hypokalemia is still lacking. The role of cardiac expression of defective skeletal muscle channels in the heart of HypoPP patients remains unclear. Clinicians should be aware of and prevent treatment-induced cardiac arrhythmia in HypoPP.

  11. 78 FR 36787 - Rechanneling the Current Cardiac Risk Paradigm: Arrhythmia Risk Assessment During Drug...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-19

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration Rechanneling the Current Cardiac Risk Paradigm: Arrhythmia... the Current Cardiac Risk Paradigm: Arrhythmia Risk Assessment During Drug Development Without...

  12. Computational approaches to understand cardiac electrophysiology and arrhythmias

    PubMed Central

    Roberts, Byron N.; Yang, Pei-Chi; Behrens, Steven B.; Moreno, Jonathan D.

    2012-01-01

    Cardiac rhythms arise from electrical activity generated by precisely timed opening and closing of ion channels in individual cardiac myocytes. These impulses spread throughout the cardiac muscle to manifest as electrical waves in the whole heart. Regularity of electrical waves is critically important since they signal the heart muscle to contract, driving the primary function of the heart to act as a pump and deliver blood to the brain and vital organs. When electrical activity goes awry during a cardiac arrhythmia, the pump does not function, the brain does not receive oxygenated blood, and death ensues. For more than 50 years, mathematically based models of cardiac electrical activity have been used to improve understanding of basic mechanisms of normal and abnormal cardiac electrical function. Computer-based modeling approaches to understand cardiac activity are uniquely helpful because they allow for distillation of complex emergent behaviors into the key contributing components underlying them. Here we review the latest advances and novel concepts in the field as they relate to understanding the complex interplay between electrical, mechanical, structural, and genetic mechanisms during arrhythmia development at the level of ion channels, cells, and tissues. We also discuss the latest computational approaches to guiding arrhythmia therapy. PMID:22886409

  13. Clinical outcome and circulatory effects of fetal cardiac arrhythmia.

    PubMed

    Lingman, G; Lundström, N R; Marsál, K

    1986-01-01

    By means of abdominal fetal ECG and non-invasive ultrasound blood flow studies 113 cases of fetal cardiac arrhythmia were classified according to the origin of arrhythmia. Pregnancy outcome was characterized by an increased frequency of fetal distress and heart malformation, and increased fetal and neonatal mortality. The following types of arrhythmia were identified: supraventricular extrasystoles (n = 84), paroxysmal tachycardia (n = 6), sinus bradycardia (n = 3), atrial flutter (n = 1), ventricular extrasystoles (n = 14), and atrioventricular block (n = 5). In 37 cases the combined Doppler and real-time ultrasound technique was used to measure fetal aortic blood flow as a means of studying the circulatory effects of the arrhythmia. Increased peak velocity, rising slope and acceleration were found in the first post-pausal beat after a supraventricular extrasystole or a missed beat; this supports the validity of Frank-Starling law for the fetal heart and suggests that a strong relationship exists between these variables and myocardial contractility. In two cases of intra-uterine heart failure, the effect of digoxin treatment in utero on the fetal aortic flow variables was studied, results indicating a positive inotropic effect of the drug on the fetal myocardium. The estimation of fetal aortic volume blood flow in cases of fetal cardiac arrhythmia is useful for early detection of fetal cardiac failure, and for monitoring the effects of intra-uterine treatment.

  14. Recent molecular insights from mutated IKS channels in cardiac arrhythmia.

    PubMed

    Dvir, Meidan; Peretz, Asher; Haitin, Yoni; Attali, Bernard

    2014-04-01

    Co-assembly of KCNQ1 with KCNE1 generates the IKS potassium current that is vital for the proper repolarization of the cardiac action potential. Mutations in either KCNQ1 or KCNE1 genes lead to life-threatening cardiac arrhythmias causing long QT syndrome, short QT syndrome, sinus bradycardia and atrial fibrillation. Findings emerging from recent studies are beginning to provide a picture of how gain-of-function and loss-of-function mutations are associated with pleiotropic cardiac phenotypes in the clinics. In this review, we discuss recent molecular insights obtained from mutations altering different structural modules of the channel complex that are essential for proper IKS function. We present the possible molecular mechanisms underlying mutations impairing the voltage sensing functions, as well as those altering the channel regulation by phosphatidylinositol-4,5-bisphosphate, calmodulin and protein kinase A. We also discuss the significance of diseased IKS channels for adequate pharmacological targeting of cardiac arrhythmias.

  15. Reduction in dynamin-2 is implicated in ischaemic cardiac arrhythmias.

    PubMed

    Shi, Dan; Xie, Duanyang; Zhang, Hong; Zhao, Hong; Huang, Jian; Li, Changming; Liu, Yi; Lv, Fei; The, Erlinda; Liu, Yuan; Yuan, Tianyou; Wang, Shiyi; Chen, Jinjin; Pan, Lei; Yu, Zuoren; Liang, Dandan; Zhu, Weidong; Zhang, Yuzhen; Li, Li; Peng, Luying; Li, Jun; Chen, Yi-Han

    2014-10-01

    Ischaemic cardiac arrhythmias cause a large proportion of sudden cardiac deaths worldwide. The ischaemic arrhythmogenesis is primarily because of the dysfunction and adverse remodelling of sarcolemma ion channels. However, the potential regulators of sarcolemma ion channel turnover and function in ischaemic cardiac arrhythmias remains unknown. Our previous studies indicate that dynamin-2 (DNM2), a cardiac membrane-remodelling GTPase, modulates ion channels membrane trafficking in the cardiomyocytes. Here, we have found that DNM2 plays an important role in acute ischaemic arrhythmias. In rat ventricular tissues and primary cardiomyocytes subjected to acute ischaemic stress, the DNM2 protein and transcription levels were markedly down-regulated. This DNM2 reduction was coupled with severe ventricular arrhythmias. Moreover, we identified that the down-regulation of DNM2 within cardiomyocytes increases the action potential amplitude and prolongs the re-polarization duration by depressing the retrograde trafficking of Nav1.5 and Kir2.1 channels. These effects are likely to account for the DNM2 defect-induced arrhythmogenic potentials. These results suggest that DNM2, with its multi-ion channel targeting properties, could be a promising target for novel antiarrhythmic therapies.

  16. Small Conductance Ca2+-Activated K+ Channels and Cardiac Arrhythmias

    PubMed Central

    Zhang, Xiao-Dong; Lieu, Deborah K.; Chiamvimonvat, Nipavan

    2015-01-01

    Small conductance Ca2+-activated K+ (SK, KCa2) channels are unique in that they are gated solely by changes in intracellular Ca2+ and hence, function to integrate intracellular Ca2+ and membrane potentials on a beat-to-beat basis. Recent studies have provided evidence for the existence and functional significance of SK channels in the heart. Indeed, our knowledge of cardiac SK channels has been greatly expanded over the past decade. Interests in cardiac SK channels are further driven by recent studies suggesting the critical roles of SK channels in human atrial fibrillation, SK channel as a possible novel therapeutic target in atrial arrhythmias and up-regulation of SK channels in heart failure (HF) in animal models and human HF. However, there remain critical gaps in our knowledge. Specifically, blockade of SK channels in cardiac arrhythmias has been shown to be both anti-arrhythmic and proarrhythmic. This contemporary review will provide an overview of the literature on the role of cardiac SK channels in cardiac arrhythmias and to serve as a discussion platform for the current clinical perspectives. At the translational level, development of SK channel blockers as a new therapeutic target in the treatment of atrial fibrillation and the possible pro-arrhythmic effects merit further considerations and investigations. PMID:25956967

  17. Optogenetic Light Crafting Tools for the Control of Cardiac Arrhythmias.

    PubMed

    Richter, Claudia; Christoph, Jan; Lehnart, Stephan E; Luther, Stefan

    2016-01-01

    The control of spatiotemporal dynamics in biological systems is a fundamental problem in nonlinear sciences and has important applications in engineering and medicine. Optogenetic tools combined with advanced optical technologies provide unique opportunities to develop and validate novel approaches to control spatiotemporal complexity in neuronal and cardiac systems. Understanding of the mechanisms and instabilities underlying the onset, perpetuation, and control of cardiac arrhythmias will enable the development and translation of novel therapeutic approaches. Here we describe in detail the preparation and optical mapping of transgenic channelrhodopsin-2 (ChR2) mouse hearts, cardiac cell cultures, and the optical setup for photostimulation using digital light processing.

  18. Cardiac arrhythmias and conduction defects in systemic sclerosis.

    PubMed

    Vacca, Alessandra; Meune, Christophe; Gordon, Jessica; Chung, Lorinda; Proudman, Susanna; Assassi, Shervin; Nikpour, Mandana; Rodriguez-Reyna, Tatiana S; Khanna, Dinesh; Lafyatis, Robert; Matucci-Cerinic, Marco; Distler, Oliver; Allanore, Yannick

    2014-07-01

    Signs and symptoms of arrhythmias or conduction defects are frequently reported in patients with SSc. These rhythm disorders may have several origins (i.e., related to primary heart involvement, pericardial disease, valvular regurgitation or pulmonary arterial hypertension) and may negatively affect the overall prognosis of these patients. It is therefore important to identify patients at high risk for cardiac arrhythmias with a complete cardiological evaluation and to identify the underlying heart disease, including SSc-related myocardial involvement. In addition, some therapeutic options in SSc patients may differ from those recommended in other populations.

  19. Electrocardiographic abnormalities and cardiac arrhythmias in chronic obstructive pulmonary disease.

    PubMed

    Goudis, Christos A; Konstantinidis, Athanasios K; Ntalas, Ioannis V; Korantzopoulos, Panagiotis

    2015-11-15

    Chronic obstructive pulmonary disease (COPD) is independently associated with an increased burden of cardiovascular disease. Besides coronary artery disease (CAD) and congestive heart failure (CHF), specific electrocardiographic (ECG) abnormalities and cardiac arrhythmias seem to have a significant impact on cardiovascular prognosis of COPD patients. Disturbances of heart rhythm include premature atrial contractions (PACs), premature ventricular contractions (PVCs), atrial fibrillation (AF), atrial flutter (AFL), multifocal atrial tachycardia (MAT), and ventricular tachycardia (VT). Of note, the identification of ECG abnormalities and the evaluation of the arrhythmic risk may have significant implications in the management and outcome of patients with COPD. This article provides a concise overview of the available data regarding ECG abnormalities and arrhythmias in these patients, including an elaborated description of the underlying arrhythmogenic mechanisms. The clinical impact and prognostic significance of ECG abnormalities and arrhythmias in COPD as well as the appropriate antiarrhythmic therapy and interventions in this setting are also discussed.

  20. A telemetry system for the study of spontaneous cardiac arrhythmias.

    PubMed

    Rollins, D L; Killingsworth, C R; Walcott, G P; Justice, R K; Ideker, R E; Smith, W M

    2000-07-01

    The characteristics of spontaneous cardiac arrhythmias leading to sudden cardiac death are largely unknown. To study arrhythmias in animal models, an eight-channel implantable radio telemetry system has been developed to record continuously cardiac electrograms over a period of weeks to months, with maintenance restricted to changing batteries. The inputs are connected in a unipolar manner. Each channel has a gain of fifty and is AC coupled, band limited to 0.07-260 Hz. The signals are digitized with 12 bits resolution at 1000 samples/s. The amplifiers, analog-to-digital converter, and control logic are packaged in an implantable unit. An umbilical cable is passed through the skin to an external backpack unit for power and data transmission. A custom serial interface card, a PC/104 form factor 25-MHz 80386-based single-board computer with a PCMCIA wireless local area network (WLAN) card, and battery power supply make up the backpack. Data are read into the parallel port of the computer, buffered, then transmitted over the WLAN to the laboratory network where it can be analyzed and archived. Approximately 12 h of 14,000 bytes/s data can be collected with each set of batteries. The system is suitable for continuous monitoring of animal models of spontaneous arrhythmias and sudden cardiac death.

  1. Arrhythmias

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Arrhythmias KidsHealth > For Teens > Arrhythmias Print A A A ... Treated? When to Call the Doctor What Are Arrhythmias? Arrhythmias are abnormal heartbeats usually caused by an ...

  2. Macrolide Antibiotics and the Risk of Cardiac Arrhythmias

    PubMed Central

    Schuller, Joseph L.

    2014-01-01

    Randomized, controlled trials have demonstrated that chronic therapy with macrolide antibiotics reduces the morbidity of patients with cystic fibrosis, non–cystic fibrosis bronchiectasis, chronic obstructive pulmonary disease, and nontuberculous mycobacterial infections. Lower levels of evidence indicate that chronic macrolides are also effective in treating patients with panbronchiolitis, bronchiolitis obliterans, and rejection after lung transplant. Macrolides are known to cause torsade des pointes and other ventricular arrhythmias, and a recent observational study prompted the FDA to strengthen the Warnings and Precautions section of azithromycin drug labels. This summary describes the electrophysiological effects of macrolides, reviews literature indicating that the large majority of subjects experiencing cardiac arrhythmias from macrolides have coexisting risk factors and that the incidence of arrhythmias in absence of coexisting risk factors is very low, examines recently published studies describing the relative risk of arrhythmias from macrolides, and concludes that this risk has been overestimated and suggests an approach to patient evaluation that should reduce the relative risk and the incidence of arrhythmias to the point that chronic macrolides can be used safely in the majority of subjects for whom they are recommended. PMID:24707986

  3. Macrolide antibiotics and the risk of cardiac arrhythmias.

    PubMed

    Albert, Richard K; Schuller, Joseph L

    2014-05-15

    Randomized, controlled trials have demonstrated that chronic therapy with macrolide antibiotics reduces the morbidity of patients with cystic fibrosis, non-cystic fibrosis bronchiectasis, chronic obstructive pulmonary disease, and nontuberculous mycobacterial infections. Lower levels of evidence indicate that chronic macrolides are also effective in treating patients with panbronchiolitis, bronchiolitis obliterans, and rejection after lung transplant. Macrolides are known to cause torsade des pointes and other ventricular arrhythmias, and a recent observational study prompted the FDA to strengthen the Warnings and Precautions section of azithromycin drug labels. This summary describes the electrophysiological effects of macrolides, reviews literature indicating that the large majority of subjects experiencing cardiac arrhythmias from macrolides have coexisting risk factors and that the incidence of arrhythmias in absence of coexisting risk factors is very low, examines recently published studies describing the relative risk of arrhythmias from macrolides, and concludes that this risk has been overestimated and suggests an approach to patient evaluation that should reduce the relative risk and the incidence of arrhythmias to the point that chronic macrolides can be used safely in the majority of subjects for whom they are recommended.

  4. Update on management of cardiac arrhythmias in acute coronary syndromes.

    PubMed

    Willich, T; Goette, A

    2015-04-01

    This review summarizes different types of arrhythmias in patients with acute coronary syndromes and provides an overview of the available therapeutic options for acute care and management of critical arrhythmias. The different therapeutic options are depending on the origin and type of arrhythmia. The main common dominant mechanisms are intramural re-entry in ischemia and triggered activity in reperfusion. The different forms of arrhythmia were explained in detail. Atrial arrhythmias are mainly atrial fibrillation; other forms are rare and usually self-limited. As therapeutic options antiarrhythmic drug therapy with beta-blockers or amiodarone and direct current cardioversion are suitable. Ventricular arrhythmias can be divided in premature ventricular complexes, accelerated idioventricular rhythm, non-sustained ventricular tachycardia, sustained ventricular tachycardia (VT), ventricular fibrillation (VF) and electrical storm. As therapeutic options antiarrhythmic drug therapy, implantable cardioverter defibrillator therapy (ICD), radiofrequency catheter ablation (RFA) and stellate ganglion blockade are available. The treatment with antiarrhythmic drug is rather cautious recommended, with the exception of beta-blockers. An additional drug therapy with ranolazine may be considered. The advantage of ICD therapy for long-term primary or secondary prophylactic therapy has been well documented. ICD therapy is associated with significant reduction in mortality compared with antiarrhythmic drug therapy (mainly amiodarone), with the exception of beta-blockers. RFA and stellate ganglion blockade are rather intended as therapeutically options for incessant VT/VF or electrical storm.

  5. Nonlinear dynamics, chaos and complex cardiac arrhythmias

    NASA Technical Reports Server (NTRS)

    Glass, L.; Courtemanche, M.; Shrier, A.; Goldberger, A. L.

    1987-01-01

    Periodic stimulation of a nonlinear cardiac oscillator in vitro gives rise to complex dynamics that is well described by one-dimensional finite difference equations. As stimulation parameters are varied, a large number of different phase-locked and chaotic rhythms is observed. Similar rhythms can be observed in the intact human heart when there is interaction between two pacemaker sites. Simplified models are analyzed, which show some correspondence to clinical observations.

  6. Cardiac arrhythmias and sudden unexpected death in epilepsy (SUDEP).

    PubMed

    Velagapudi, Poonam; Turagam, Mohit; Laurence, Thomas; Kocheril, Abraham

    2012-03-01

    Sudden unexpected death in epilepsy (SUDEP) is a major clinical problem in epilepsy patients in the United States, especially those with chronic, uncontrolled epilepsy. Several pathophysiological events contributing to SUDEP include cardiac arrhythmias, respiratory dysfunction, and dysregulation of systemic or cerebral circulation. There is a significant body of literature suggesting the prominent role of cardiac arrhythmias in the pathogenesis of SUDEP. There is evidence to say that long-standing epilepsy can cause physiological and anatomical autonomic instability resulting in life-threatening arrhythmias. Tachyarrhythmias, bradyarrhythmias, and asystole are commonly seen during ictal, interictal, and postictal phase in epilepsy patients. It is unclear if these rhythm disturbances need attention as some of them may be just benign findings. Evidence regarding prolonged cardiovascular monitoring or the benefit of pacemaker/defibrillator implantation for primary or secondary prevention in epilepsy patients is limited. Awareness regarding pathophysiology, cardiac effects, and management options of SUDEP will become useful in guiding more individualized treatment in the near future. (PACE 2011; 1-8).

  7. Disruption of cardiac cholinergic neurons enhances susceptibility to ventricular arrhythmias

    PubMed Central

    Jungen, Christiane; Scherschel, Katharina; Eickholt, Christian; Kuklik, Pawel; Klatt, Niklas; Bork, Nadja; Salzbrunn, Tim; Alken, Fares; Angendohr, Stephan; Klene, Christiane; Mester, Janos; Klöcker, Nikolaj; Veldkamp, Marieke W.; Schumacher, Udo; Willems, Stephan; Nikolaev, Viacheslav O.; Meyer, Christian

    2017-01-01

    The parasympathetic nervous system plays an important role in the pathophysiology of atrial fibrillation. Catheter ablation, a minimally invasive procedure deactivating abnormal firing cardiac tissue, is increasingly becoming the therapy of choice for atrial fibrillation. This is inevitably associated with the obliteration of cardiac cholinergic neurons. However, the impact on ventricular electrophysiology is unclear. Here we show that cardiac cholinergic neurons modulate ventricular electrophysiology. Mechanical disruption or pharmacological blockade of parasympathetic innervation shortens ventricular refractory periods, increases the incidence of ventricular arrhythmia and decreases ventricular cAMP levels in murine hearts. Immunohistochemistry confirmed ventricular cholinergic innervation, revealing parasympathetic fibres running from the atria to the ventricles parallel to sympathetic fibres. In humans, catheter ablation of atrial fibrillation, which is accompanied by accidental parasympathetic and concomitant sympathetic denervation, raises the burden of premature ventricular complexes. In summary, our results demonstrate an influence of cardiac cholinergic neurons on the regulation of ventricular function and arrhythmogenesis. PMID:28128201

  8. Brainstem sources of cardiac vagal tone and respiratory sinus arrhythmia

    PubMed Central

    Farmer, David G.S.; Dutschmann, Mathias; Paton, Julian F.R.; Pickering, Anthony E.

    2016-01-01

    Key points Cardiac vagal tone is a strong predictor of health, although its central origins are unknown.Respiratory‐linked fluctuations in cardiac vagal tone give rise to respiratory sinus arryhthmia (RSA), with maximum tone in the post‐inspiratory phase of respiration.In the present study, we investigated whether respiratory modulation of cardiac vagal tone is intrinsically linked to post‐inspiratory respiratory control using the unanaesthetized working heart‐brainstem preparation of the rat.Abolition of post‐inspiration, achieved by inhibition of the pontine Kolliker‐Fuse nucleus, removed post‐inspiratory peaks in efferent cardiac vagal activity and suppressed RSA, whereas substantial cardiac vagal tone persisted. After transection of the caudal pons, part of the remaining tone was removed by inhibition of nucleus of the solitary tract.We conclude that cardiac vagal tone depends upon at least 3 sites of the pontomedullary brainstem and that a significant proportion arises independently of RSA. Abstract Cardiac vagal tone is a strong predictor of health, although its central origins are unknown. The rat working heart‐brainstem preparation shows strong cardiac vagal tone and pronounced respiratory sinus arrhythmia. In this preparation, recordings from the cut left cardiac vagal branch showed efferent activity that peaked in post‐inspiration, ∼0.5 s before the cyclic minimum in heart rate (HR). We hypothesized that respiratory modulation of cardiac vagal tone and HR is intrinsically linked to the generation of post‐inspiration. Neurons in the pontine Kölliker‐Fuse nucleus (KF) were inhibited with bilateral microinjections of isoguvacine (50–70 nl, 10 mm) to remove the post‐inspiratory phase of respiration. This also abolished the post‐inspiratory peak of cardiac vagal discharge (and cyclical HR modulation), although a substantial level of activity remained. In separate preparations with intact cardiac vagal branches but

  9. Acute cardiac arrhythmias following surgery for congenital heart disease: mechanisms, diagnostic tools, and management.

    PubMed

    Payne, Linda; Zeigler, Vicki L; Gillette, Paul C

    2011-06-01

    This article focuses on the management of those cardiac arrhythmias most commonly seen in the immediate postoperative period. They include ventricular tachycardia, ventricular fibrillation, atrial flutter, junctional ectopic tachycardia, bradycardia, and atrioventricular block. The mechanisms of cardiac arrhythmias are reviewed followed by a brief overview of the predominant acute arrhythmias, tools used for the diagnostic evaluation of these arrhythmias, management strategies, and, finally, nursing considerations.

  10. Electrocardiographic abnormalities and cardiac arrhythmias in structural brain lesions.

    PubMed

    Katsanos, Aristeidis H; Korantzopoulos, Panagiotis; Tsivgoulis, Georgios; Kyritsis, Athanassios P; Kosmidou, Maria; Giannopoulos, Sotirios

    2013-07-31

    Cardiac arrhythmias and electrocardiographic abnormalities are frequently observed after acute cerebrovascular events. The precise mechanism that leads to the development of these arrhythmias is still uncertain, though increasing evidence suggests that it is mainly due to autonomic nervous system dysregulation. In massive brain lesions sympathetic predominance and parasympathetic withdrawal during the first 72 h are associated with the occurrence of severe secondary complications in the first week. Right insular cortex lesions are also related with sympathetic overactivation and with a higher incidence of electrocardiographic abnormalities, mostly QT prolongation, in patients with ischemic stroke. Additionally, female sex and hypokalemia are independent risk factors for severe prolongation of the QT interval which subsequently results in malignant arrhythmias and poor outcome. The prognostic value of repolarization changes commonly seen after aneurysmal subarachnoid hemorrhage, such as ST segment, T wave, and U wave abnormalities, still remains controversial. In patients with traumatic brain injury both intracranial hypertension and cerebral hypoperfusion correlate with low heart rate variability and increased mortality. Given that there are no firm guidelines for the prevention or treatment of the arrhythmias that appear after cerebral incidents this review aims to highlight important issues on this topic. Selected patients with the aforementioned risk factors could benefit from electrocardiographic monitoring, reassessment of the medications that prolong QTc interval, and administration of antiadrenergic agents. Further research is required in order to validate these assumptions and to establish specific therapeutic strategies.

  11. Statistical Versus Individual Forecasting Of Life-Threatening Cardiac Arrhythmias

    NASA Astrophysics Data System (ADS)

    Wessel, Niels; Meyerfeldt, Udo; Ziehmann, Christine; Schirdewan, Alexander; Kurths, Jürgen

    2002-07-01

    Ventricular tachycardia or fibrillation (VT) as fatal cardiac arrhythmias are the main factors triggering sudden cardiac death. The objective of this investigation is to find early signs of sustained VT in patients with an implanted cardioverter-defibrillator (ICD). These devices are able to safeguard patients by returning their hearts to a normal rhythm via strong defibrillatory shocks; additionally, they are able to store at least 1000 beat-to-beat intervals immediately before the onset of a life-threatening arrhythmia. We study these 1000 beat-to-beat intervals of 63 chronic heart failure ICD patients before the onset of a life-threatening arrhythmia and at a control time, i.e. without VT event. To characterize these rather short data sets, we calculate heart rate variability (HRV) parameters from time and frequency domain, from symbolic dynamics as well as the finite-time growth rates. We find that no linear parameter shows significant differences in HRV between the VT and the control time series. However, the nonlinear parameters detected a significant increase in short phases with low variability before the onset of VT (p<0.05, for time series with less than 10% ectopy). Finally, we are investigating whether these results may lead to individual predictions of VT.

  12. The role of the autonomic nervous system in arrhythmias and sudden cardiac death.

    PubMed

    Franciosi, Sonia; Perry, Frances K G; Roston, Thomas M; Armstrong, Kathryn R; Claydon, Victoria E; Sanatani, Shubhayan

    2017-03-31

    The autonomic nervous system (ANS) is complex and plays an important role in cardiac arrhythmia pathogenesis. A deeper understanding of the anatomy and development of the ANS has shed light on its involvement in cardiac arrhythmias. Alterations in levels of Sema-3a and NGF, both growth factors involved in innervation patterning during development of the ANS, leads to cardiac arrhythmias. Dysregulation of the ANS, including polymorphisms in genes involved in ANS development, have been implicated in sudden infant death syndrome. Disruptions in the sympathetic and/or parasympathetic systems of the ANS can lead to cardiac arrhythmias and can vary depending on the type of arrhythmia. Simultaneous stimulation of both the sympathetic and parasympathetic systems is thought to lead to atrial fibrillation whereas increased sympathetic stimulation is thought to lead to ventricular fibrillation or ventricular tachycardia. In inherited arrhythmia syndromes, such as Long QT and Catecholaminergic Polymorphic Ventricular Tachycardia, sympathetic system stimulation is thought to lead to ventricular tachycardia, subsequent arrhythmias, and in severe cases, cardiac death. On the other hand, arrhythmic events in Brugada Syndrome have been associated with periods of high parasympathetic tone. Increasing evidence suggests that modulation of the ANS as a therapeutic strategy in the treatment of cardiac arrhythmias is safe and effective. Further studies investigating the involvement of the ANS in arrhythmia pathogenesis and its modulation for the treatment of cardiac arrhythmias is warranted.

  13. Insulin tolerance test causes hypokalaemia and can provoke cardiac arrhythmias.

    PubMed

    Binder, Gerhard; Bosk, Axel; Gass, Matthias; Ranke, Michael B; Heidemann, Peter H

    2004-01-01

    We report the observation and analysis of a new adverse event during the insulin tolerance test (ITT) and propose additional safety procedures. An 8-year-old girl with growth hormone insufficiency had a cardiac arrest due to ventricular flutter when she was tested for growth hormone deficiency by the ITT. Severe hypokalaemia (K+ 2.6 mmol/l) was observed after resuscitation. Ergometry ECG revealed catecholaminergic polymorphic ventricular tachycardia, a hereditary arrhythmogenic disease. Consecutive measurements of serum potassium during ITT in 29 short children (21 boys) with growth failure revealed a mean decrease of serum potassium by 1.1 +/- 0.4 mmol/l with the nadir at 30 min after the insulin bolus. Hypokalaemia (serum potassium < 3.5 mmol/l) occurred in all but one child; severe hypokalaemia (serum potassium < 2.9 mmol/l) was measured in every third child. This observation indicates that acute hypokalaemia which is induced by insulin and catecholamine excess occurs frequently in ITT. The case shows that the combination of acute hypokalaemia and the adrenergic counterregulation in ITT is a strong trigger of cardiac arrhythmias, which can become life-threatening if the child has an arrhythmogenic disease. Therefore, we recommend ECG monitoring during ITT to enhance the detection of cardiac arrhythmias. In addition, in the case of a comatose child during ITT the determination of the glucose and potassium level as well as adequate treatment are necessary.

  14. Cardiac arrhythmia in Wilson's disease: An oversighted and overlooked entity!

    PubMed Central

    Bajaj, Bhupender Kumar; Wadhwa, Ankur; Singh, Richa; Gupta, Saurabh

    2016-01-01

    Wilson's disease is a multisystem disorder which manifests with hepatic, neurological, musculoskeletal, hematological, renal, and cardiac symptoms. The hepatic and neurological manifestations often overshadow the other system involvement including cardiac symptoms and signs, which may prove fatal. We report a case of a young female who presented with progressive parkinsonian features and dystonia for around 4 months followed 2 months later by the complaint of episodes of light-headedness. She was diagnosed to have Wilson's disease based on the presence of Kayser–Fleischer ring and laboratory parameters of copper metabolism. Electrocardiography of the patient incidentally revealed 2nd degree Mobitz type-1 atrioventricular block explaining her episodes of light-headedness. She was started on penicillamine and trihexyphenidyl. The heart block improved spontaneously. Cardiac autonomic function tests including blood pressure response to standing and heart rate response to standing were observed to be normal. We review the literature on cardiac manifestations of Wilson's disease and emphasize that patients with Wilson's disease should be assessed for cardiac arrhythmia and cardiac dysfunction as these may have therapeutic and prognostic implications. PMID:27695244

  15. Amiodarone for refractory cardiac arrhythmias: 10-year study.

    PubMed Central

    Leak, D; Eydt, J N

    1986-01-01

    Over a 10-year period 130 patients with drug-resistant cardiac arrhythmias associated mainly with coronary artery disease and its complications were treated with amiodarone. The drug controlled all the tachyarrhythmias associated with the Wolff-Parkinson-White syndrome, 95% of the ventricular arrhythmias, including recurrent ventricular tachycardia and fibrillation, and 92% of the supraventricular arrhythmias. The maximum duration of therapy was 111 months and the mean 34 months. Side effects occurred in 34% of the patients, and there was one withdrawal from therapy per 15.3 patient-years of treatment. The commonest cause of withdrawal was nausea, which was significantly related (p less than 0.01) to a drug interaction with digoxin and diuretics. Reversible neurologic complications occurred in eight patients (6%), and acute myositis was recognized for the first time. Pulmonary infiltration developed in four patients (3%), who were receiving 600 mg of amiodarone per day. The rates of side effects and of withdrawal from therapy differed significantly between the patients whose maintenance doses were 600 and 200 mg/d, at 59% v. 6% (p less than 0.01) and 32% v. 0% (p less than 0.05) respectively. Thus, amiodarone is a very effective antiarrhythmic that can be administered over long periods with acceptable rates of side effects and withdrawal provided the minimal effective dose is used; 400 mg/d or less is desirable. PMID:3948063

  16. Oxidative stress, fibrosis, and early afterdepolarization-mediated cardiac arrhythmias.

    PubMed

    Karagueuzian, Hrayr S; Nguyen, Thao P; Qu, Zhilin; Weiss, James N

    2013-01-01

    Animal and clinical studies have demonstrated that oxidative stress, a common pathophysiological factor in cardiac disease, reduces repolarization reserve by enhancing the L-type calcium current, the late Na, and the Na-Ca exchanger, promoting early afterdepolarizations (EADs) that can initiate ventricular tachycardia and ventricular fibrillation (VT/VF) in structurally remodeled hearts. Increased ventricular fibrosis plays a key facilitatory role in allowing oxidative-stress induced EADs to manifest as triggered activity and VT/VF, since normal non-fibrotic hearts are resistant to arrhythmias when challenged with similar or higher levels of oxidative stress. The findings imply that antifibrotic therapy, in addition to therapies designed to suppress EAD formation at the cellular level, may be synergistic in reducing the risk of sudden cardiac death.

  17. Oxidative stress, fibrosis, and early afterdepolarization-mediated cardiac arrhythmias

    PubMed Central

    Karagueuzian, Hrayr S.; Nguyen, Thao P.; Qu, Zhilin; Weiss, James N.

    2013-01-01

    Animal and clinical studies have demonstrated that oxidative stress, a common pathophysiological factor in cardiac disease, reduces repolarization reserve by enhancing the L-type calcium current, the late Na, and the Na-Ca exchanger, promoting early afterdepolarizations (EADs) that can initiate ventricular tachycardia and ventricular fibrillation (VT/VF) in structurally remodeled hearts. Increased ventricular fibrosis plays a key facilitatory role in allowing oxidative-stress induced EADs to manifest as triggered activity and VT/VF, since normal non-fibrotic hearts are resistant to arrhythmias when challenged with similar or higher levels of oxidative stress. The findings imply that antifibrotic therapy, in addition to therapies designed to suppress EAD formation at the cellular level, may be synergistic in reducing the risk of sudden cardiac death. PMID:23423152

  18. A Powerful Algorithm to aid Cardiac Arrhythmia Diagnosis.

    PubMed

    Bereksi-Reguig, F.; Hadj Slimane, Z. E.

    2000-01-01

    The Electrocardiogram (ECG), represents the electrical activity of the heart. It is characterised by a number of waves P, QRS, T which are correlated to the status of the heart activity. In this paper, the aim is to present a powerful algorithm to aid cardiac diagnosis. The approach used is based on a determinist method, that of the tree decision. However, the different waves of the ECG signal need to be identified and then measured following a signal to noise enhancement. Signal to noise enhancement is performed by a combiner linear adaptive filter whereas P, QRS, T wave identification and measurement are performed by a derivative approach. Results obtained on simulated and real ECG signals are shown to be highly, satisfactory in the aid of cardiac arrhythmia diagnosis, such as junctionnal escapes, blocks, etc.

  19. Cardiac arrhythmias produced by ultrasound and contrast agents

    NASA Astrophysics Data System (ADS)

    Rota, Claudio

    Ultrasound is used widely in medicine for both diagnostic and therapeutic applications. Ultrasound contrast agents are suspensions of gas-filled microbubbles used to enhance diagnostic imaging. Microbubble contrast agents can increase the likelihood of bioeffects of ultrasound associated with acoustic cavitation. Under certain exposure conditions, the interaction of ultrasound with cardiac tissues can produce cardiac arrhythmias. The general objective of this thesis was to develop a greater understanding of ultrasound-induced premature cardiac beats. The hypothesis guiding this work was that acoustic cavitation is the physical mechanism for the production of arrhythmias with ultrasound. This hypothesis was tested through a series of experiments with mice in vivo and theoretical investigations. Results of this research supported the acoustic cavitation hypothesis. The acoustic pressure threshold for premature beats was significantly lower with microbubble contrast agents present in the blood than without. With microbubbles, the threshold for premature beats was below the current output limits of diagnostic devices. The threshold was not significantly dependent upon contrast agent type and was not influenced by contrast agent dose over three orders of magnitude. Furthermore, the dependence of the threshold on acoustic frequency was consistent with the frequency dependence of acoustic cavitation. Experimentally determined thresholds for premature beats in vivo were in excellent agreement with theoretically estimated thresholds for inertial cavitation. A passive cavitation detector (PCD) was used to measure the acoustic emissions produced by cavitating microbubbles in vivo. A direct correlation between the amplitude of the PCD and the percentage of ultrasound pulses producing a premature beat was consistent with cavitation as a mechanism for this bioeffect. Although this thesis focused on the mechanistic understanding of ultrasound-induced arrhythmias, more persistent

  20. Detection and Prevention of Cardiac Arrhythmias During Space Flight

    NASA Technical Reports Server (NTRS)

    Pillai, Dilip; Rosenbaum, David S.; Liszka, Kathy J.; York, David W.; Mackin, Michael A.; Lichter, Michael J.

    2004-01-01

    There have been reports suggesting that long-duration space flight might lead to an increased risk of potentially serious heart rhythm disturbances. If space flight does, in fact, significantly decrease cardiac electrical stability, the effects could be catastrophic, potentially leading to sudden cardiac death. It will be important to determine the mechanisms underlying this phenomenon in order to prepare for long-term manned lunar and interplanetary missions and to develop appropriate countermeasures. Electrical alternans affecting the ST segment and T-wave have been demonstrated to be common among patients at increased risk for ventricular arrhythmias. Subtle electrical alternans on the ECG may serve as a noninvasive marker of vulnerability to ventricular arrhythmias. We are studying indices of electrical instability in the heart for long term space missions by non-invasively measuring microvolt level T-wave alternans in a reduced gravity environment. In this investigation we are using volunteer subjects on the KC-135 aircraft as an initial study of the effect of electrical adaptation of the heart to microgravity. T-wave alternans will be analyzed for heart rate variability and QT restitution curve plotting will be compared for statistical significance.

  1. Arrhythmias, Sudden Cardiac Death and incapacitation of pilots

    PubMed Central

    Mantziari, L; Styliadis, C; Kourtidou-Papadeli, C; Styliadis, I

    2008-01-01

    Inflight medical emergencies occur at a rate of 20 to 100 per million passengers, with a death rate of 0.1 to 1 per million. Cardiac, neurologic, and respiratory complaints comprise the more serious emergencies, as defined by aircraft diversion or use of ground-based medical assistance. In this paper, we review changes seen in the resting electrocardiogram in normal individuals exposed to high altitude, alongside important implications for patients with heart diseases in high altitude exposures and the possible effects of high altitude to permanent cardiac pacemakers. Arrhythmias in pilots and public safety are revisited together with the guidelines of the Joint Aviation Requirements (JAR) in Europe. The situation of Military flights is also discussed. Physicians ought to become knowledgeable about the specific medical job standards for their patients when asked to render opinions regarding fitness to fly. A database must be established to obtain prospective data that defines the risk of accidents in patients who are or were being treated for arrhythmias. Current guidelines could then be updated and revised as appropriate. PMID:19050752

  2. Role of CaMKII in cardiac arrhythmias

    PubMed Central

    Hund, Thomas J.; Mohler, Peter J.

    2014-01-01

    Protein phosphorylation is a central mechanism in vertebrates for the regulation of signaling. With regard to the cardiovascular system, phosphorylation of myocyte targets is critical for the regulation of excitation contraction coupling, metabolism, intracellular calcium regulation, mitochondrial activity, transcriptional regulation, and cytoskeletal dynamics. In fact, pathways that tune protein kinase signaling have been a mainstay for cardiovascular therapies for the past 60 years. The calcium/calmodulin-dependent protein kinase II (CaMKII) is a multifunctional serine/threonine kinase with numerous roles in human physiology. Dysfunction in CaMKII-based signaling has been linked with a host of cardiovascular phenotypes including heart failure and arrhythmia, and CaMKII levels are elevated in human and animal disease models of heart disease. While nearly a decade has been invested in targeting CaMKII for the treatment of heart failure and arrhythmia phenotypes, to date, approaches to target the molecule for antiarrhythmic benefit have been unsuccessful for reasons that are still not entirely clear, although (1) lack of compound specificity and (2) the multitude of downstream targets are likely contributing factors. This review will provide an update on current pathways regulated by CaMKII with the goal of illustrating potential upstream regulatory mechanisms and downstream targets that may be modulated for the prevention of cardiac electrical defects. While the review will cover multiple aspects of CaMKII dysfunction in cardiovascular disease, we have given special attention to the potential of CaMKII-associated late Na+ current as a novel therapeutic target for cardiac arrhythmia. PMID:25577293

  3. Aconitine "challenge" test reveals a single whole-body exposure to diesel exhaust increases cardiac arrhythmia risk in hypertensive rats

    EPA Science Inventory

    Epidemiological studies demonstrate a significant association between cardiac electrical dysfunction, arrhythmias and air pollution exposure. Sensitivity to aconitine-induced arrhythmia has been used repeatedly to examine the factors that increase the risk of such cardiac electri...

  4. Arrhythmia

    MedlinePlus

    An arrhythmia is a problem with the rate or rhythm of your heartbeat. It means that your heart beats ... is called bradycardia. The most common type of arrhythmia is atrial fibrillation, which causes an irregular and ...

  5. Arrhythmias

    MedlinePlus Videos and Cool Tools

    A change in the heart's normal electrical conduction system can result in an arrhythmia or irregular heartbeat. An arrhythmia can be an abnormally slow heartbeat, or an abnormally fast heartbeat. In ...

  6. Arrhythmia

    MedlinePlus

    ... from the NHLBI on Twitter. What Is an Arrhythmia? Español An arrhythmia (ah-RITH-me-ah) is a problem with ... rate or rhythm of the heartbeat. During an arrhythmia, the heart can beat too fast, too slow, ...

  7. Electromechanical coupling in the cardiac myocyte; stretch-arrhythmia feedback.

    PubMed

    ter Keurs, Henk E D J

    2011-07-01

    The macroscopic hallmarks of the normal heartbeat are rapid onset of contraction and rapid relaxation and an inotropic response to both increased end diastolic volume and increased heart rate. At the microscopic level, the calcium ion (Ca(2+)) plays a crucial role in normal cardiac contraction. This paper reviews the cycle of Ca(2+) fluxes during the normal heartbeat, which underlie the coupling between excitation and contraction (ECC) and permit a highly synchronized action of cardiac sarcomeres. Length dependence of the response of the regulatory sarcomeric proteins mediates the Frank-Starling Law of the heart. However, Ca(2+) transport may go astray in heart disease and both jeopardize the exquisite mechanism of systole and diastole and triggering arrhythmias. The interplay between weakened and strong segments in nonuniform cardiac muscle may further lead to mechanoelectric feedback-or reverse excitation contraction coupling (RECC) mediating an early diastolic Ca(2+) transient caused by the rapid force decrease during the relaxation phase. These rapid force changes in nonuniform muscle may cause arrhythmogenic Ca(2+) waves to propagate by activation of neighbouring SR by diffusing Ca(2+) ions.

  8. Exact coherent structures: from fluid turbulence to cardiac arrhythmias

    NASA Astrophysics Data System (ADS)

    Grigoriev, Roman; Marcotte, Christopher; Byrne, Gregory

    2014-03-01

    Ventricular fibrillation, a life threatening cardiac arrhythmia, is an example of spatiotemporally chaotic state dominated by multiple interacting spiral waves. Recent studies of weak fluid turbulence suggest that spatiotemporal chaos in general can be understood as a walk among exact unstable regular solutions (exact coherent states, ECS) of nonlinear evolution equations. Several classes of ECS are believed to play a dominant role; most typically these are equilibria and periodic orbits or relative equilibria and relative periodic orbits for systems with global continuous symmetries. Numerical methods originally developed in the context of fluid turbulence can also be applied to models of cardiac dynamics which possess translational and rotational symmetries and, indeed, allowed us to identify relative equilibria and periodic orbits describing isolated spirals with, respectively, fixed and drifting cores. In order to find regular solutions featuring multiple interacting spirals a new approach is required that takes into consideration the dynamics of slowly drifting cores associated with local, rather than global, symmetries. We describe how local symmetries can be reduced and more general types of ECS computed that dominate spiral wave chaos in models of cardiac tissue.

  9. Noninvasive Cardiac Screening in Young Athletes With Ventricular Arrhythmias

    PubMed Central

    Steriotis, Alexandros Klavdios; Nava, Andrea; Rigato, Ilaria; Mazzotti, Elisa; Daliento, Luciano; Thiene, Gaetano; Basso, Cristina; Corrado, Domenico; Bauce, Barbara

    2013-01-01

    The aim of this study was to analyze using noninvasive cardiac examinations a series of young athletes discovered to have ventricular arrhythmias (VAs) during the preparticipation screening program for competitive sports. One hundred forty-five athletes (mean age 17 ± 5 years) were evaluated. The study protocol included electrocardiography (ECG), exercise testing, 2-dimensional and Doppler echocardiography, 24-hour Holter monitoring, signal-averaged ECG, and in selected cases contrast-enhanced cardiac magnetic resonance imaging. Results of ECG were normal in most athletes (85%). VAs were initially detected prevalently during exercise testing (85%) and in the remaining cases on ECG and Holter monitoring. Premature ventricular complexes disappeared during exercise in 56% of subjects. Premature ventricular complexes during Holter monitoring averaged 4,700 per day, predominantly monomorphic (88%), single, and/or in couplets (79%). The most important echocardiographic findings were mitral valve prolapse in 29 patients (20%), congenital heart disease in 4 (3%), and right ventricular regional kinetic abnormalities in 5 (3.5%). On cardiac magnetic resonance imaging, right ventricular regional kinetic abnormalities were detected in 9 of 30 athletes and were diagnostic of arrhythmogenic right ventricular cardiomyopathy in only 1 athlete. Overall, 30% of athletes were judged to have potentially dangerous VAs. In asymptomatic athletes with prevalently normal ECG, most VAs can be identified by adding an exercise test during preparticipation screening. In conclusion, cardiac screening with noninvasive examinations remains a fundamental tool for the identification of a possible pathologic substrate and for the characterization of electrical instability. PMID:23219000

  10. Intra-beat Scaling Properties of Cardiac Arrhythmias and Sudden Cardiac Death

    NASA Astrophysics Data System (ADS)

    Rodríguez, Eduardo; Lerma, Claudia; Echeverría, Juan C.; Alvarez-Ramirez, Jose

    2008-02-01

    We applied detrended fluctuation analysis (DFA) to characterize the intra-beat scaling dynamics of electrocardiographic (ECG) recordings from the PhysioNet Sudden Cardiac Death Holter Database. The main finding of this contribution is that, in such recordings involving different types of arrhythmias; the ECG waveform, besides showing a less-random intra-beat dynamics, becomes more regular during bigeminy, ventricular tachycardia (VT) or even atrial fibrillation (AFIB) and ventricular fibrillation (VF) despite the appearance of erratic traces. Thus, notwithstanding that these cardiac rhythm abnormalities are generally considered as irregular and some of them generated by random impulses or wavefronts, the intra-beat scaling properties suggest that regularity dominates the underlying mechanisms of arrhythmias. Among other explanations, this may result from shorted or restricted -less complex- pathways of conduction of the electrical activity within the ventricles.

  11. Clinical impact of genetic studies in lethal inherited cardiac arrhythmias.

    PubMed

    Shimizu, Wataru

    2008-12-01

    Over the past decade, molecular genetic studies have established a link between a number of inherited cardiac arrhythmias, including congenital long QT syndrome (LQTS) and Brugada syndrome (BrS), and mutations in genes encoding for ion channels or other membrane components. Twelve forms of LQTS have been identified in 50-70% of clinically affected patients. Genotype-phenotype correlations have been rigorously investigated in LQT1, LQT2 and LQT3 syndromes, which constitute more than 90% of genotyped LQTS patients, enabling stratification of risk and effective treatment of genotyped patients. Genotype-specific triggers for both the cardiac events and the clinical course have been reported, and genotype-specific therapy has been already introduced. More recently, mutation site-specific differences in the clinical phenotype have been reported in LQT1 and LQT2 patients, indicating the possibility of mutation site-specific management or treatment. In contrast, only one-third of BrS patients can be genotyped, and data on genotype-phenotype relationships in clinical studies are limited. A Haplotype B consisting of 6 individual DNA polymorphisms within the proximal promoter region of the SCN5A gene was recently identified only in Asians (frequency 22%). Individuals with Haplotype B show significantly longer duration of both PQ and QRS than those without Haplotype B, indicating that Haplotype B likely contributes to the higher incidence of BrS in Asian populations.

  12. Ryanodine receptor-mediated arrhythmias and sudden cardiac death

    PubMed Central

    Blayney, Lynda M.; Lai, F. Anthony

    2009-01-01

    The cardiac ryanodine receptor-Ca2+ release channel (RyR2) is an essential sarcoplasmic reticulum (SR) transmembrane protein that plays a central role in excitation–contraction coupling (ECC) in cardiomyocytes. Aberrant spontaneous, diastolic Ca2+ leak from the SR due to dysfunctional RyR2 contributes to the formation of delayed after-depolarisations, which are thought to underlie the fatal arrhythmia that occurs in both heart failure (HF) and in catecholaminergic polymorphic ventricular tachycardia (CPVT). CPVT is an inherited disorder associated with mutations in either the RyR2 or a SR luminal protein, calsequestrin. RyR2 shows normal function at rest in CPVT but the RyR2 dysfunction is unmasked by physical exercise or emotional stress, suggesting abnormal RyR2 activation as an underlying mechanism. Several potential mechanisms have been advanced to explain the dysfunctional RyR2 observed in HF and CPVT, including enhanced RyR2 phosphorylation status, altered RyR2 regulation at luminal/cytoplasmic sites and perturbed RyR2 intra/inter-molecular interactions. This review considers RyR2 dysfunction in the context of the structural and functional modulation of the channel, and potential therapeutic strategies to stabilise RyR2 function in cardiac pathology. PMID:19345240

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

    PubMed

    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.

  14. Detection and Prevention of Cardiac Arrhythmias During Space Flight

    NASA Technical Reports Server (NTRS)

    Pillai, Dilip; Rosenbaum, David S.; Liszka, Kathy J.; York, David W.; Mackin, Michael A.; Lichter, Michael J.

    2004-01-01

    There have been reports suggesting that long-duration space flight might lead to an increased risk of potentially serious heart rhythm disturbances. If space flight does, in fact, significantly decrease cardiac electrical stability, the effects could be catastrophic, potentially leading to sudden cardiac death. It will be important to determine the mechanisms underlying this phenomenon in order to prepare for long-term manned lunar and interplanetary missions and to develop appropriate countermeasures. Our hypothesis is that prolonged exposure to microgravity will alter T wave alternans measurements, decrease heart rate variance, increase QT dispersion, decrease heart rate recovery and alter QT restitution curve. A recently published study has shown that long duration spaceflights prolong cardiac conduction and repolarization. They concluded that long duration flight is associated with QT interval prolongation and may increase arrhythmia susceptibility. We propose using computer technology as a noninvasive clinical tool to detect and study clinically significant TWA during standard exercise testing using electrode systems specifically adapted for the purpose of obtaining and measuring TWA. A population of approximately 15 healthy men and 5 healthy women subjects, representative of the astronaut cohort will be asked to voluntarily participate in this study. Their blood pressure and ECG/TWA will be measured pre-flight and in-flight. Prior to flight, subjects will be asked to participate in an orientation session. Still photos will be taken of the skin where the conductive gel is used for the multi-segment sensors. Photos will be recorded preflight, immediately postflight, and several times during the proceeding week until it has been determined that any skin reaction has disappeared or that no rash is present and will not appear.

  15. A possible mechanism of halocarbon-induced cardiac sensitization arrhythmias

    PubMed Central

    Jiao, Zhe; De Jesús, Víctor R.; Iravanian, Shahriar; Campbell, Daniel P.; Xu, Jie; Vitali, Juan A.; Banach, Kathrin; Fahrenbach, John; Dudley, Samuel C.

    2011-01-01

    Cardiac sensitization is the term used for malignant ventricular arrhythmias associated with exposure to inhaled halocarbons in the presence of catecholamines. We investigated the electrophysiological changes associated with cardiomyocyte exposure to epinephrine and a halocarbon known to be associated with cardiac sensitization (halon 1301, CF3Br). Cardiomyocytes (CMs) were isolated from neonatal rats and grown on multielectrode arrays (MEAs). Upon exposure to epinephrine, the CM inter-spike interval (ISI) was decreased 14% at 10 µg/L (P<0.05) and 27% at 100 µg/L (P<0.05) as compared to baseline. Halon alone (50 mg/L) mildly prolonged the field potential (FP) duration (7%). CMs exposed to combinations of epinephrine (100 µg/L) and halon (50 mg/L) for 15 min showed a blunted increase in the ISI (35±12%) and a 38% decrease in conduction velocity (P<0.05) when compared to epinephrine alone. There was no change in field potential properties, but dephosphorylated connexin 43 (Cx43) was increased 60±16% with the combination as compared to epinephrine alone (P<0.05). Treatment with okadaic acid, a phosphatase inhibitor, prevented the Cx43 dephosphorylation and the reduction in conduction velocity upon exposure to halon and epinephrine. Moreover, the electrophysiological changes induced by epinephrine and halon were indistinguishable from those seen with the gap junction inhibitor heptanol. In conclusion, the combination of a halocarbon and epinephrine results in a unique electrophysiological signature including slow conduction that may explain, in part, the basis for cardiac sensitization. The slowing of conduction is most likely related to changes in the phosphorylation state of Cx43. PMID:16919292

  16. Cardiac arrhythmias associated with a liquid protein diet for the treatment of obesity

    SciTech Connect

    Lantigua, R.A.; Amatruda, J.M.; Biddle, T.L.; Forbes, G.B.; Lockwood, D.H.

    1980-09-25

    Our data demonstrate that a liquid protein diet is frequently associated with potentially life-threatening arrhythmias that are not detected on routine electrocardiography. Several studies of metabolic balance failed to reveal a cause for these arrhythmias. We recommended that the use of liquid protein diets should be terminated pending further investigation of the causes and prevention of the cardiac toxicity.

  17. Cardiac Arrhythmias in Patients with Chronic Kidney Disease: Implications of Renal Failure for Antiarrhythmic Drug Therapy.

    PubMed

    Potpara, Tatjana S; Jokic, Vera; Dagres, Nikolaos; Marin, Francisco; Prostran, Milica S; Blomstrom-Lundqvist, Carina; Lip, Gregory Y H

    2016-01-01

    The kidney has numerous complex interactions with the heart, including shared risk factors (e.g., hypertension, dyslipidemia, etc.) and mutual amplification of morbidity and mortality. Both cardiovascular diseases and chronic kidney disease (CKD) may cause various alterations in cardiovascular system, metabolic homeostasis and autonomic nervous system that may facilitate the occurrence of cardiac arrhythmias. Also, pre-existent or incident cardiac arrhythmias such as atrial fibrillation (AF) may accelerate the progression of CKD. Patients with CKD may experience various cardiac rhythm disturbances including sudden cardiac death. Contemporary management of cardiac arrhythmias includes the use of antiarrhythmic drugs (AADs), catheter ablation and cardiac implantable electronic devices (CIEDs). Importantly, AADs are not used only as the principal treatment strategy, but also as an adjunct therapy in combination with CIEDs, to facilitate their effects or to minimize inappropriate device activation in selected patients. Along with their principal antiarrhythmic effect, AADs may also induce cardiac arrhythmias and the risk for such proarrhythmic effect(s) is particularly increased in patients with reduced left ventricular systolic function or in the setting of electrolyte imbalance. Moreover, CKD itself can induce profound alterations in the pharmacokinetics and pharmacodynamics of many drugs including AADs, thus facilitating the drug accumulation and increased exposure. Hence, the use of AADs in patients with CKD may be challenging. In this review article, we provide an overview of the characteristics of arrhythmogenesis in patients with CKD with special emphasis on the complexity of pharmacokinetics and risk for proarrhythmias when using AADs in patients with cardiac arrhythmias and CKD.

  18. The Role of Late INa in Development of Cardiac Arrhythmias

    PubMed Central

    Antzelevitch, Charles; Nesterenko, Vladislav; Shryock, John C.; Rajamani, Sridharan; Song, Yejia; Belardinelli, Luiz

    2014-01-01

    Late INa is an integral part of the sodium current, which persists long after the fast-inactivating component. The magnitude of the late INa is relatively small in all species and in all types of cardiomyocytes as compared with the amplitude of the fast sodium current, but it contributes significantly to the shape and duration of the action potential. This late component had been shown to increase in several acquired or congenital conditions, including hypoxia, oxidative stress, and heart failure, or due to mutations in SCN5A, which encodes the α-subunit of the sodium channel, as well as in channel-interacting proteins, including multiple β subunits and anchoring proteins. Patients with enhanced late INa exhibit the type-3 long QT syndrome (LQT3) characterized by high propensity for the life-threatening ventricular arrhythmias, such as Torsade de Pointes (TdP), as well as for atrial fibrillation. There are several distinct mechanisms of arrhythmogenesis due to abnormal late INa, including abnormal automaticity, early and delayed afterdepolarization-induced triggered activity, and dramatic increase of ventricular dispersion of repolarization. Many local anesthetic and antiarrhythmic agents have a higher potency to block late INa as compared with fast INa. Several novel compounds, including ranolazine, GS-458967, and F15845, appear to be the most selective inhibitors of cardiac late INa reported to date. Selective inhibition of late INa is expected to be an effective strategy for correcting these acquired and congenital channelopathies. PMID:24737235

  19. Arrhythmia

    MedlinePlus

    ... are some of the types of arrhythmias?Atrial fibrillation: The heart beats too fast and irregularly. This ... or congenital heart failure).Ventricular tachycardia and ventricular fibrillation: The heart beats too fast and may not ...

  20. Aconitine Challenge Test Reveals a Single Exposure to Air Pollution Causes Increased Cardiac Arrhythmia Risk in Hypertensive Rats - Abstract

    EPA Science Inventory

    Epidemiological studies demonstrate a significant association between arrhythmias and air pollution exposure. Sensitivity to aconitine-induced arrhythmia has been used repeatedly to examine the factors that increase the risk of such cardiac electrical dysfunction. In this study, ...

  1. The electrocardiogram in the assessment of the effect of drugs on cardiac arrhythmias.

    PubMed Central

    Reid, D S

    1978-01-01

    The search for the ideal antiarrhythmic drug continues since none of the available agents offers optimum antiarrhythmic therapy. The continuing search coupled with the interest in the mechanisms of cardiac arrhythmias has led to the development of new techniques for the study of arrhythmias and antiarrhythmic drugs. In this article it is proposed to discuss the electrocardiographic methods used in the assessment of antiarrhythmic drugs. Firstly, to discuss the electrocardiogram in the assessment of the clinical electrophysiological properties of a drug and secondly, the electrocardiogram in the assessment of the value of the drug in the management of cardiac arrhythmias in man. PMID:365208

  2. Interventional and surgical treatment of cardiac arrhythmias in adults with congenital heart disease.

    PubMed

    Koyak, Zeliha; de Groot, Joris R; Mulder, Barbara J M

    2010-12-01

    Arrhythmias are a major cause of morbidity, mortality and hospital admission in adults with congenital heart disease (CHD). The etiology of arrhythmias in this population is often multifactorial and includes electrical disturbances as part of the underlying defect, surgical intervention or hemodynamic abnormalities. Despite the numerous existing arrhythmia management tools including drug therapy, pacing and ablation, management of arrhythmias in adults with CHD remains difficult and challenging. Owing to improvement in mapping and ablation techniques, ablation and arrhythmia surgery are being performed more frequently in adults with CHD. However, there is little information on the long-term results of these treatment strategies. The purpose of this article is therefore to review the available data on nonpharmacological treatment of cardiac arrhythmias in adult patients with CHD and to give an overview of the available data on the early and late outcomes of these treatment strategies.

  3. Light-based Approaches to Cardiac Arrhythmia Research: From Basic Science to Translational Applications

    PubMed Central

    Karathanos, Thomas V.; Boyle, Patrick M.; Trayanova, Natalia A.

    2016-01-01

    Light has long been used to image the heart, but now it can be used to modulate its electrophysiological function. Imaging modalities and techniques have long constituted an indispensable part of arrhythmia research and treatment. Recently, advances in the fields of optogenetics and photodynamic therapy have provided scientists with more effective approaches for probing, studying and potentially devising new treatments for cardiac arrhythmias. This article is a review of research toward the application of these techniques. It contains (a) an overview of advancements in technology and research that have contributed to light-based cardiac applications and (b) a summary of current and potential future applications of light-based control of cardiac cells, including modulation of heart rhythm, manipulation of cardiac action potential morphology, quantitative analysis of arrhythmias, defibrillation and cardiac ablation. PMID:27840581

  4. Mice with cardiac overexpression of PPARγ have impaired repolarization and spontaneous fatal ventricular arrhythmias (Morrow, PPARγ overexpression induces fatal arrhythmias)

    PubMed Central

    Morrow, John P.; Katchman, Alexander; Son, Ni-Huiping; Trent, Chad M.; Khan, Raffay; Shiomi, Takayuki; Huang, Haiyan; Amin, Vaibhav; Lader, Joshua M.; Vasquez, Carolina; Morley, Gregory E.; D'Armiento, Jeanine; Homma, Shunichi; Goldberg, Ira J.; Marx, Steven O.

    2011-01-01

    Background Diabetes and obesity, which confer an increased risk of sudden cardiac death, are associated with cardiomyocyte lipid accumulation and altered cardiac electrical properties, manifested by prolongation of the QRS duration and QT interval. It is difficult to distinguish the contribution of cardiomyocyte lipid accumulation versus the contribution of global metabolic defects to the increased incidence of sudden death and electrical abnormalities. Methods and Results In order to study the effects of metabolic abnormalities on arrhythmias without the complex systemic effects of diabetes and obesity, we studied cardiac-specific transgenic mice expressing PPARγ1 via the cardiac α-myosin heavy-chain promoter. The PPARγ-transgenic mice develop abnormal accumulation of intracellular lipids and die as young adults, prior to a significant reduction in systolic function. Using implantable ECG telemeters, we found that these mice have prolongation of the QRS and QT intervals, and spontaneous ventricular arrhythmias, including polymorphic ventricular tachycardia and ventricular fibrillation. Isolated cardiomyocytes demonstrated prolonged action potential duration caused by reduced expression and function of the potassium channels responsible for repolarization. Short-term exposure to pioglitazone, a PPARγ agonist, had no effect on mortality or rhythm in WT mice, but further exacerbated the arrhythmic phenotype and increased the mortality in the PPARγ TG mice. Conclusions Our findings support an important link between PPARγ activation, cardiomyocyte lipid accumulation, ion channel remodeling and increased cardiac mortality. PMID:22124376

  5. Sex differences in cardiac electrophysiology and clinical arrhythmias: epidemiology, therapeutics, and mechanisms.

    PubMed

    Tadros, Rafik; Ton, Anh-Tuan; Fiset, Céline; Nattel, Stanley

    2014-07-01

    Sex differences in cardiac electrophysiological properties and arrhythmias are evident in epidemiologic and investigative studies as well as in daily patient care. At the supraventricular level, women are at increased risk of sick sinus syndrome and atrioventricular (AV) node re-entrant tachycardia, whereas men manifest more AV block and accessory pathway-mediated arrhythmias. At the ventricular level, women are generally at higher risk of long QT-associated arrhythmias, whereas men are more likely to present with early repolarization, idiopathic ventricular fibrillation, and Brugada syndromes. Great advances have been made in unraveling the fundamental mechanisms underlying sex differences in ventricular arrhythmias, particularly those associated with abnormal repolarization. Conversely, the basis for male-predominant arrhythmia risk in structural heart disease and differences in supraventricular arrhythmia susceptibility are poorly understood. Beyond biological differences, arrhythmia occurrence and patient care decisions are also influenced by gender-related factors. This article reviews the current knowledge regarding the nature and underlying mechanisms of sex differences in basic cardiac electrophysiology and clinical arrhythmias.

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

    NASA Technical Reports Server (NTRS)

    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.

  7. Immediate effect on cardiac output of reversion to sinus rhythm from rapid arrhythmias.

    PubMed

    Wright, J S; Fabian, J; Epstein, E J

    1970-08-08

    Cardiac output was estimated immediately before and after conversion to sinus rhythm in nine patients with rapid arrhythmias. Conversion was by synchronized direct-current shock in eight patients, and by direct atrial wall stimulation in the other. In seven patients there was an immediate increase in cardiac output after restoration of sinus rhythm. The percentage increase in output was directly proportional to the rate of the arrhythmia immediately before conversion (r=0.91, P<0.01). The critical heart rate, above which an immediate increase in cardiac output might be expected on conversion to sinus rhythm, appeared in these patients to be about 160 beats per minute.

  8. Sympathetic restraint of respiratory sinus arrhythmia: implications for vagal-cardiac tone assessment in humans

    NASA Technical Reports Server (NTRS)

    Taylor, J. A.; Myers, C. W.; Halliwill, J. R.; Seidel, H.; Eckberg, D. L.

    2001-01-01

    Clinicians and experimentalists routinely estimate vagal-cardiac nerve traffic from respiratory sinus arrhythmia. However, evidence suggests that sympathetic mechanisms may also modulate respiratory sinus arrhythmia. Our study examined modulation of respiratory sinus arrhythmia by sympathetic outflow. We measured R-R interval spectral power in 10 volunteers that breathed sequentially at 13 frequencies, from 15 to 3 breaths/min, before and after beta-adrenergic blockade. We fitted changes of respiratory frequency R-R interval spectral power with a damped oscillator model: frequency-dependent oscillations with a resonant frequency, generated by driving forces and modified by damping influences. beta-Adrenergic blockade enhanced respiratory sinus arrhythmia at all frequencies (at some, fourfold). The damped oscillator model fit experimental data well (39 of 40 ramps; r = 0.86 +/- 0.02). beta-Adrenergic blockade increased respiratory sinus arrhythmia by amplifying respiration-related driving forces (P < 0.05), without altering resonant frequency or damping influences. Both spectral power data and the damped oscillator model indicate that cardiac sympathetic outflow markedly reduces heart period oscillations at all frequencies. This challenges the notion that respiratory sinus arrhythmia is mediated simply by vagal-cardiac nerve activity. These results have important implications for clinical and experimental estimation of human vagal cardiac tone.

  9. The role of the Arrhythmia Team, an integrated, multidisciplinary approach to treatment of patients with cardiac arrhythmias: results of the European Heart Rhythm Association survey.

    PubMed

    Fumagalli, Stefano; Chen, Jian; Dobreanu, Dan; Madrid, Antonio Hernandez; Tilz, Roland; Dagres, Nikolaos

    2016-04-01

    Management of patients with cardiac arrhythmias is increasingly complex because of continuous technological advance and multifaceted clinical conditions associated with ageing of the population, the presence of co-morbidities and the need for polypharmacy. The aim of this European Heart Rhythm Association Scientific Initiatives Committee survey was to provide an insight into the role of the Arrhythmia Team, an integrated, multidisciplinary approach to management of patients with cardiac arrhythmias. Forty-eight centres from 18 European countries replied to the Web-based questionnaire. The presence of an Arrhythmia Team was reported by 44% of the respondents, whereas 17% were not familiar with this term. Apart from the electrophysiologist, health professionals who should belong to such teams, according to the majority of the respondents, include a clinical cardiologist, a nurse, a cardiac surgeon, a heart failure specialist, a geneticist, and a geriatrician. Its main activity should be dedicated to the management of patients with complex clinical conditions or refractory or inherited forms of arrhythmias. When present, the Arrhythmia Team was considered helpful by 95% of respondents; the majority of centres (79%) agreed that it should be implemented. The Arrhythmia Team seems to be connected to important expectations in the management of cardiac arrhythmias. The efficacy of such an integrated and multidisciplinary approach should be encouraged and tested in clinical practice.

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

    PubMed

    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.

  11. [Magnesium deficiency and therapy in cardiac arrhythmias: recommendations of the German Society for Magnesium Research].

    PubMed

    Vierling, W; Liebscher, D-H; Micke, O; von Ehrlich, B; Kisters, K

    2013-05-01

    Aim of the recommendations of the German Society for Magnesium Research: Recognition and compensation of magnesium deficiency in patients with risk factors for cardiac arrhythmias or manifest rhythm disturbances. Prevention of arrhythmias by administration of magnesium. Therapeutic administration of magnesium in patients with arrhythmias with and without magnesium deficiency. The current state of knowledge claims for considering the status of magnesium and the possibility of a therapeutic intervention with magnesium within the concept of the treatment of cardiovascular diseases. The use of magnesium as single agent or as an adjunct to other therapeutic actions in the prevention and therapy of cardiac arrhythmias can be effective and, in case of oral administration, very safe. In case of parenteral administration, it is important to use adequate doses, monitor cardiovascular and neuromuscular parameters and to consider contraindications.

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

    PubMed

    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.

  13. Severity of nocturnal cardiac arrhythmias correlates with intensity of sleep apnea in men.

    PubMed

    Szaboova, E; Holoubek, D; Tomori, Z; Szabo, P; Donic, V; Stancak, B

    2013-01-01

    Various cardiac arrhythmias frequently occur in patients with sleep apnea, but complex analysis of the relationship between their severity and the probable arrhythmogenic risk factors is conflicting. The question is what cardiovascular risk factors and how strongly they are associated with the severity of cardiac arrhythmias in sleep apnea. Adult males (33 with and 16 without sleep apnea), matched for cardiovascular co-morbidity were studied by polysomnography with simultaneous ECG monitoring. Arrhythmia severity was evaluated for each subject by a special 7-degree scoring system. Laboratory, clinical, echocardiographic, carotid ultrasonographic, ambulatory blood pressure, and baroreflex sensitivity values were also assessed. Moderate sleep apnea patients had benign, but more exaggerated cardiac arrhythmias than control subjects (2.53 ± 2.49 vs. 1.13 ± 1.64 degrees of cumulative severity, p < 0.05). We confirmed strong correlations between the arrhythmia severity and known arrhythmogenic risk factors (left ventricular ejection fraction and dimensions, right ventricular diameter, baroreflex sensitivity, carotid intima-media thickness, age, previous myocardial infarction, and also apnea-hypopnea index). In multivariate modelling only the apnea-hypopnea index indicating the sleep apnea intensity remained highly significantly correlated with the cumulative arrhythmia severity (beta = 0.548, p < 0.005). In conclusion, sleep apnea modifying cardiovascular risk factors and structures or functions provoked various nocturnal arrhythmias. The proposed scoring system allowed a complex analysis of the contribution of various triggers to arrhythmogenesis and confirmed the apnea-hypopnea index as an independent risk for nocturnal cardiac arrhythmia severity in sleep apnea.

  14. Risk of cardiac arrhythmias during hypoglycemia in patients with type 2 diabetes and cardiovascular risk.

    PubMed

    Chow, Elaine; Bernjak, Alan; Williams, Scott; Fawdry, Robert A; Hibbert, Steve; Freeman, Jenny; Sheridan, Paul J; Heller, Simon R

    2014-05-01

    Recent trials of intensive glycemic control suggest a possible link between hypoglycemia and excess cardiovascular mortality in patients with type 2 diabetes. Hypoglycemia might cause arrhythmias through effects on cardiac repolarization and changes in cardiac autonomic activity. Our aim was to study the risk of arrhythmias during spontaneous hypoglycemia in type 2 diabetic patients with cardiovascular risk. Twenty-five insulin-treated patients with type 2 diabetes and a history of cardiovascular disease or two or more risk factors underwent simultaneous continuous interstitial glucose and ambulatory electrocardiogram monitoring. Frequency of arrhythmias, heart rate variability, and markers of cardiac repolarization were compared between hypoglycemia and euglycemia and between hyperglycemia and euglycemia matched for time of day. There were 134 h of recording at hypoglycemia, 65 h at hyperglycemia, and 1,258 h at euglycemia. Bradycardia and atrial and ventricular ectopic counts were significantly higher during nocturnal hypoglycemia compared with euglycemia. Arrhythmias were more frequent during nocturnal versus daytime hypoglycemia. Excessive compensatory vagal activation after the counterregulatory phase may account for bradycardia and associated arrhythmias. QT intervals, corrected for heart rate, >500 ms and abnormal T-wave morphology were observed during hypoglycemia in some participants. Hypoglycemia, frequently asymptomatic and prolonged, may increase the risk of arrhythmias in patients with type 2 diabetes and high cardiovascular risk. This is a plausible mechanism that could contribute to increased cardiovascular mortality during intensive glycemic therapy.

  15. Protective effects of isorhynchophylline on cardiac arrhythmias in rats and guinea pigs.

    PubMed

    Gan, Runtao; Dong, Guo; Yu, Jiangbo; Wang, Xu; Fu, Songbin; Yang, Shusen

    2011-09-01

    As one important constituent extracted from a traditional Chinese medicine, Uncaria Rhynchophylla Miq Jacks, isorhynchophylline has been used to treat hypertension, epilepsy, headache, and other illnesses. Whether isorhynchophylline protects hearts against cardiac arrhythmias is still incompletely investigated. This study was therefore aimed to examine the preventive effects of isorhynchophylline on heart arrhythmias in guinea pigs and rats and then explore their electrophysiological mechanisms. In vivo, ouabain and calcium chloride were used to establish experimental arrhythmic models in guinea pigs and rats. In vitro, the whole-cell patch-lamp technique was used to study the effect of isorhynchophylline on action potential duration and calcium channels in acutely isolated guinea pig and rat cardiomyocytes. The dose of ouabain required to induce cardiac arrhythmias was much larger in guinea pigs administered with isorhynchophylline. Additionally, the onset time of cardiac arrhythmias induced by calcium chloride was prolonged, and the duration was shortened in rats pretreated with isorhynchophylline. The further study showed that isorhynchophylline could significantly decrease action potential duration and inhibit calcium currents in isolated guinea pig and rat cardiomyocytes in a dose-dependent manner. In summary, isorhynchophylline played a remarkably preventive role in cardiac arrhythmias through the inhibition of calcium currents in rats and guinea pigs.

  16. 3D X-ray imaging methods in support catheter ablations of cardiac arrhythmias.

    PubMed

    Stárek, Zdeněk; Lehar, František; Jež, Jiří; Wolf, Jiří; Novák, Miroslav

    2014-10-01

    Cardiac arrhythmias are a very frequent illness. Pharmacotherapy is not very effective in persistent arrhythmias and brings along a number of risks. Catheter ablation has became an effective and curative treatment method over the past 20 years. To support complex arrhythmia ablations, the 3D X-ray cardiac cavities imaging is used, most frequently the 3D reconstruction of CT images. The 3D cardiac rotational angiography (3DRA) represents a modern method enabling to create CT like 3D images on a standard X-ray machine equipped with special software. Its advantage lies in the possibility to obtain images during the procedure, decreased radiation dose and reduction of amount of the contrast agent. The left atrium model is the one most frequently used for complex atrial arrhythmia ablations, particularly for atrial fibrillation. CT data allow for creation and segmentation of 3D models of all cardiac cavities. Recently, a research has been made proving the use of 3DRA to create 3D models of other cardiac (right ventricle, left ventricle, aorta) and non-cardiac structures (oesophagus). They can be used during catheter ablation of complex arrhythmias to improve orientation during the construction of 3D electroanatomic maps, directly fused with 3D electroanatomic systems and/or fused with fluoroscopy. An intensive development in the 3D model creation and use has taken place over the past years and they became routinely used during catheter ablations of arrhythmias, mainly atrial fibrillation ablation procedures. Further development may be anticipated in the future in both the creation and use of these models.

  17. Sympathetic cardiac hyperinnervation and atrial autonomic imbalance in diet-induced obesity promote cardiac arrhythmias.

    PubMed

    McCully, Belinda H; Hasan, Wohaib; Streiff, Cole T; Houle, Jennifer C; Woodward, William R; Giraud, George D; Brooks, Virginia L; Habecker, Beth A

    2013-11-15

    Obesity increases the risk of arrhythmias and sudden cardiac death, but the mechanisms are unknown. This study tested the hypothesis that obesity-induced cardiac sympathetic outgrowth and hyperinnervation promotes the development of arrhythmic events. Male Sprague-Dawley rats (250-275 g), fed a high-fat diet (33% kcal/fat), diverged into obesity-resistant (OR) and obesity-prone (OP) groups and were compared with rats fed normal chow (13% kcal/fat; CON). In vitro experiments showed that both OR and OP rats exhibited hyperinnervation of the heart and high sympathetic outgrowth compared with CON rats, even though OR rats are not obese. Despite the hyperinnervation and outgrowth, we showed that, in vivo, OR rats were less susceptible to arrhythmic events after an intravenous epinephrine challenge compared with OP rats. On examining total and stimulus-evoked neurotransmitter levels in an ex vivo system, we demonstrate that atrial acetylcholine content and release were attenuated in OP compared with OR and CON groups. OP rats also expressed elevated atrial norepinephrine content, while norepinephrine release was suppressed. These findings suggest that the consumption of a high-fat diet, even in the absence of overt obesity, stimulates sympathetic outgrowth and hyperinnervation of the heart. However, normalized cardiac parasympathetic nervous system control may protect the heart from arrhythmic events.

  18. Epileptic Patients are at Risk of Cardiac Arrhythmias: A Novel Approach using QT-nomogram, Tachogram, and Cardiac Restitution Plots

    PubMed Central

    Al-Nimer, Marwan S.; Al-Mahdawi, Sura A.; Abdullah, Namir M.; Al-Mahdawi, Akram

    2017-01-01

    Background: Sudden death is reported in patients who had a history of epilepsy and some authors believed that is due to cardiac arrhythmias. Objectives: This study aimed to predict that the epileptic patients are at risk of serious cardiac arrhythmias by QT-nomogram, tachogram (Lorenz), and cardiac restitution plots. Methods: A total number of 71 healthy subjects (Group I) and 64 newly diagnosed epileptic patients (Group II) were recruited from Al-Yarmouk and Baghdad Teaching hospitals in Baghdad from March 2015 to July 2015 and included in this study. The diagnosis of epilepsy achieved clinically, electroencephalograph record and radio-images including computerized tomography and magnetic image resonance. At the time of entry into the study, an electrocardiography (ECG) was done, and the determinants of each ECG record were calculated. The QT-nomogram, tachogram, and cardiac restitution plots were used to identify the patients at risk of cardiac arrhythmias. Results: Significant prolonged corrected QT corrected (QTc) and JT corrected intervals were observed in female compared with male at age ≥50 years while the TQ interval was significantly prolonged in males of Group II. Eight patients of Group II had a significant pathological prolonged QTc interval compared with undetectable finding in Group I. QT nomogram did not disclose significant findings while the plots of Lorenz and restitution steepness disclose that the patients of Group II were vulnerable to cardiac arrhythmias. Abnormal ECG findings were observed in the age extremities (≤18 years and ≥50 years) in Group II compared with Group I. Conclusion: Utilization of QT-nomogram, restitution steepness, and tachogram plots is useful tools for detection subclinical vulnerable epileptic patient with cardiac arrhythmias. PMID:28149075

  19. Fetal cardiac arrhythmia detection and in utero therapy

    PubMed Central

    Strasburger, Janette F.; Wakai, Ronald T.

    2010-01-01

    The human fetal heart develops arrhythmias and conduction disturbances in response to ischemia, inflammation, electrolyte disturbances, altered load states, structural defects, inherited genetic conditions, and many other causes. Yet sinus rhythm is present without altered rate or rhythm in some of the most serious electrophysiological diseases, which makes detection of diseases of the fetal conduction system challenging in the absence of magnetocardiographic or electrocardiographic recording techniques. Life-threatening changes in QRS or QT intervals can be completely unrecognized if heart rate is the only feature to be altered. For many fetal arrhythmias, echocardiography alone can assess important clinical parameters for diagnosis. Appropriate treatment of the fetus requires awareness of arrhythmia characteristics, mechanisms, and potential associations. Criteria to define fetal bradycardia specific to gestational age are now available and may allow detection of ion channelopathies, which are associated with fetal and neonatal bradycardia. Ectopic beats, once thought to be entirely benign, are now recognized to have important pathologic associations. Fetal tachyarrhythmias can now be defined precisely for mechanism-specific therapy and for subsequent monitoring of response. This article reviews the current and future diagnostic techniques and pharmacologic treatments for fetal arrhythmia. PMID:20418904

  20. Severe hypoglycemia-induced lethal cardiac arrhythmias are mediated by sympathoadrenal activation.

    PubMed

    Reno, Candace M; Daphna-Iken, Dorit; Chen, Y Stefanie; VanderWeele, Jennifer; Jethi, Krishan; Fisher, Simon J

    2013-10-01

    For people with insulin-treated diabetes, severe hypoglycemia can be lethal, though potential mechanisms involved are poorly understood. To investigate how severe hypoglycemia can be fatal, hyperinsulinemic, severe hypoglycemic (10-15 mg/dL) clamps were performed in Sprague-Dawley rats with simultaneous electrocardiogram monitoring. With goals of reducing hypoglycemia-induced mortality, the hypotheses tested were that: 1) antecedent glycemic control impacts mortality associated with severe hypoglycemia; 2) with limitation of hypokalemia, potassium supplementation could limit hypoglycemia-associated deaths; 3) with prevention of central neuroglycopenia, brain glucose infusion could prevent hypoglycemia-associated arrhythmias and deaths; and 4) with limitation of sympathoadrenal activation, adrenergic blockers could prevent hypoglycemia-induced arrhythmic deaths. Severe hypoglycemia-induced mortality was noted to be worsened by diabetes, but recurrent antecedent hypoglycemia markedly improved the ability to survive an episode of severe hypoglycemia. Potassium supplementation tended to reduce mortality. Severe hypoglycemia caused numerous cardiac arrhythmias including premature ventricular contractions, tachycardia, and high-degree heart block. Intracerebroventricular glucose infusion reduced severe hypoglycemia-induced arrhythmias and overall mortality. β-Adrenergic blockade markedly reduced cardiac arrhythmias and completely abrogated deaths due to severe hypoglycemia. Under conditions studied, sudden deaths caused by insulin-induced severe hypoglycemia were mediated by lethal cardiac arrhythmias triggered by brain neuroglycopenia and the marked sympathoadrenal response.

  1. Non-Linear Dynamics of Cardiac Alternans: Subcellular to Tissue-Level Mechanisms of Arrhythmia

    PubMed Central

    Gaeta, Stephen A.; Christini, David J.

    2012-01-01

    Cardiac repolarization alternans is a rhythm disturbance of the heart in which rapid stimulation elicits a beat-to-beat alternation in the duration of action potentials and magnitude of intracellular calcium transients in individual cardiac myocytes. Although this phenomenon has been identified as a potential precursor to dangerous reentrant arrhythmias and sudden cardiac death, significant uncertainty remains regarding its mechanism and no clinically practical means of halting its occurrence or progression currently exists. Cardiac alternans has well-characterized tissue, cellular, and subcellular manifestations, the mechanisms and interplay of which are an active area of research. PMID:22783195

  2. Asymmetric sympathetic output: The dorsomedial hypothalamus as a potential link between emotional stress and cardiac arrhythmias.

    PubMed

    Fontes, Marco Antônio Peliky; Filho, Marcelo Limborço; Santos Machado, Natália L; de Paula, Cristiane Amorim; Souza Cordeiro, Letícia M; Xavier, Carlos Henrique; Marins, Fernanda Ribeiro; Henderson, Luke; Macefield, Vaughan G

    2017-01-17

    The autonomic response to emotional stress, while involving several target organs, includes an important increase in sympathetic drive to the heart. There is ample evidence that cardiac sympathetic innervation is lateralized, and asymmetric autonomic output to the heart during stress is postulated to be a causal factor that precipitates cardiac arrhythmias. Recent animal studies provided a new picture of the central pathways involved in the cardiac sympathetic response evoked by emotional stress, pointing out a key role for the region of dorsomedial hypothalamus. However, how much of this information can be extrapolated to humans? Analysis of human functional imaging data at rest or during emotional stress shows some consistency with the components that integrate these pathways, and attention must be given to the asymmetric activation of subcortical sites. In this short review, we will discuss related findings in humans and animals, aiming to understand the neurogenic background for the origin of emotional stress-induced cardiac arrhythmias.

  3. Hindlimb unloading results in increased predisposition to cardiac arrhythmias and alters left ventricular connexin 43 expression.

    PubMed

    Moffitt, Julia A; Henry, Matthew K; Welliver, Kathryn C; Jepson, Amanda J; Garnett, Emily R

    2013-03-01

    Hindlimb unloading (HU) is a well-established animal model of cardiovascular deconditioning. Previous data indicate that HU results in cardiac sympathovagal imbalance. It is well established that cardiac sympathovagal imbalance increases the risk for developing cardiac arrhythmias. The cardiac gap junction protein connexin 43 (Cx43) is predominately expressed in the left ventricle (LV) and ensures efficient cell-to-cell electrical coupling. In the current study we wanted to test the hypothesis that HU would result in increased predisposition to cardiac arrhythmias and alter the expression and/or phosphorylation of LV-Cx43. Electrocardiographic data using implantable telemetry were obtained over a 10- to 14-day HU or casted control (CC) condition and in response to a sympathetic stressor using isoproterenol administration and brief restraint. The arrhythmic burden was calculated using a modified scoring system to quantify spontaneous and provoked arrhythmias. In addition, Western blot analysis was used to measure LV-Cx43 expression in lysates probed with antibodies directed against the total and an unphosphorylated form of Cx43 in CC and HU rats. HU resulted in a significantly greater total arrhythmic burden during the sympathetic stressor with significantly more ventricular arrhythmias occurring. In addition, there was increased expression of total LV-Cx43 observed with no difference in the expression of unphosphorylated LV-Cx43. Specifically, the increased expression of LV-Cx43 was consistent with the phosphorylated form. These data taken together indicate that cardiovascular deconditioning produced through HU results in increased predisposition to cardiac arrhythmias and increased expression of phosphorylated LV-Cx43.

  4. Simulation of Cardiac Arrhythmias Using a 2D Heterogeneous Whole Heart Model

    PubMed Central

    Balakrishnan, Minimol; Chakravarthy, V. Srinivasa; Guhathakurta, Soma

    2015-01-01

    Simulation studies of cardiac arrhythmias at the whole heart level with electrocardiogram (ECG) gives an understanding of how the underlying cell and tissue level changes manifest as rhythm disturbances in the ECG. We present a 2D whole heart model (WHM2D) which can accommodate variations at the cellular level and can generate the ECG waveform. It is shown that, by varying cellular-level parameters like the gap junction conductance (GJC), excitability, action potential duration (APD) and frequency of oscillations of the auto-rhythmic cell in WHM2D a large variety of cardiac arrhythmias can be generated including sinus tachycardia, sinus bradycardia, sinus arrhythmia, sinus pause, junctional rhythm, Wolf Parkinson White syndrome and all types of AV conduction blocks. WHM2D includes key components of the electrical conduction system of the heart like the SA (Sino atrial) node cells, fast conducting intranodal pathways, slow conducting atriovenctricular (AV) node, bundle of His cells, Purkinje network, atrial, and ventricular myocardial cells. SA nodal cells, AV nodal cells, bundle of His cells, and Purkinje cells are represented by the Fitzhugh-Nagumo (FN) model which is a reduced model of the Hodgkin-Huxley neuron model. The atrial and ventricular myocardial cells are modeled by the Aliev-Panfilov (AP) two-variable model proposed for cardiac excitation. WHM2D can prove to be a valuable clinical tool for understanding cardiac arrhythmias. PMID:26733873

  5. Congenital Deafness with Cardiac Arrhythmias: The Jervell and Lange-Nielsen Syndrome.

    ERIC Educational Resources Information Center

    Wahl, Richard A.; Macdonald, Dick, II

    1980-01-01

    The Jervell and Lange-Nielsen syndrome, affecting 0.3 percent of congenitally deaf persons, consists of severe cardiac arrhythmias and sensorineural hearing loss. The authors recommend that every congenitally deaf child with suspicious symptoms receive an electrocardiogram and that professionals who work with deaf children not only inform…

  6. Simulation of Cardiac Arrhythmias Using a 2D Heterogeneous Whole Heart Model.

    PubMed

    Balakrishnan, Minimol; Chakravarthy, V Srinivasa; Guhathakurta, Soma

    2015-01-01

    Simulation studies of cardiac arrhythmias at the whole heart level with electrocardiogram (ECG) gives an understanding of how the underlying cell and tissue level changes manifest as rhythm disturbances in the ECG. We present a 2D whole heart model (WHM2D) which can accommodate variations at the cellular level and can generate the ECG waveform. It is shown that, by varying cellular-level parameters like the gap junction conductance (GJC), excitability, action potential duration (APD) and frequency of oscillations of the auto-rhythmic cell in WHM2D a large variety of cardiac arrhythmias can be generated including sinus tachycardia, sinus bradycardia, sinus arrhythmia, sinus pause, junctional rhythm, Wolf Parkinson White syndrome and all types of AV conduction blocks. WHM2D includes key components of the electrical conduction system of the heart like the SA (Sino atrial) node cells, fast conducting intranodal pathways, slow conducting atriovenctricular (AV) node, bundle of His cells, Purkinje network, atrial, and ventricular myocardial cells. SA nodal cells, AV nodal cells, bundle of His cells, and Purkinje cells are represented by the Fitzhugh-Nagumo (FN) model which is a reduced model of the Hodgkin-Huxley neuron model. The atrial and ventricular myocardial cells are modeled by the Aliev-Panfilov (AP) two-variable model proposed for cardiac excitation. WHM2D can prove to be a valuable clinical tool for understanding cardiac arrhythmias.

  7. Rescue of mutated cardiac ion channels in inherited arrhythmia syndromes.

    PubMed

    Balijepalli, Sadguna Y; Anderson, Corey L; Lin, Eric C; January, Craig T

    2010-08-01

    Inherited arrhythmia syndromes comprise an increasingly complex group of diseases involving mutations in multiple genes encoding ion channels, ion channel accessory subunits and channel interacting proteins, and various regulatory elements. These mutations serve to disrupt normal electrophysiology in the heart, leading to increased arrhythmogenic risk and death. These diseases have added impact as they often affect young people, sometimes without warning. Although originally thought to alter ion channel function, it is now increasingly recognized that mutations may alter ion channel protein and messenger RNA processing, to reduce the number of channels reaching the surface membrane. For many of these mutations, it is also known that several interventions may restore protein processing of mutant channels to increase their surface membrane expression toward normal. In this article, we reviewed inherited arrhythmia syndromes, focusing on long QT syndrome type 2, and discuss the complex biology of ion channel trafficking and pharmacological rescue of disease-causing mutant channels. Pharmacological rescue of misprocessed mutant channel proteins, or their transcripts providing appropriate small molecule drugs can be developed, has the potential for novel clinical therapies in some patients with inherited arrhythmia syndromes.

  8. Incidence of cardiac arrhythmias in asymptomatic hereditary hemochromatosis subjects with C282Y homozygosity.

    PubMed

    Shizukuda, Yukitaka; Tripodi, Dorothy J; Zalos, Gloria; Bolan, Charles D; Yau, Yu-Ying; Leitman, Susan F; Waclawiw, Myron A; Rosing, Douglas R

    2012-03-15

    It is not well known whether systemic iron overload per se in hereditary hemochromatosis (HH) is associated with cardiac arrhythmias before other signs and symptoms of cardiovascular disease occur. In the present study, we examined the incidence of cardiac arrhythmia in cardiac asymptomatic subjects with HH (New York Heart Association functional class I) and compared it to that in age- and gender-matched normal volunteers. The 42 subjects with HH and the 19 normal control subjects were recruited through the National Heart, Lung, and Blood Institute-sponsored "Heart Study of Hemochromatosis." They completed 48-hour Holter electrocardiography ambulatory monitoring at the baseline evaluation. The subjects with HH were classified as newly diagnosed (group A) and chronically treated (group B) subjects. All subjects with HH had C282Y homozygosity, and the normal volunteers lacked any HFE gene mutations known to cause HH. Although statistically insignificant, the incidence of ventricular and supraventricular ectopy tended to be greater in the combined HH groups than in the controls. Supraventricular ectopy was more frequently noted in group B compared to in the controls (ectopy rate per hour 11.1 ± 29.9 vs 1.5 ± 3.5, p < 0.05, using the Kruskal-Wallis test). No examples of heart block, other than first-degree atrioventricular node block, were seen in any of the subjects. The incidence of cardiac arrhythmias was not significantly reduced after 6 months of intensive iron removal therapy in the group A subjects. No life-threatening arrhythmias were observed in our subjects with HH. In conclusion, our data suggest that the incidence of cardiac arrhythmias is, at most, marginally increased in asymptomatic subjects with HH. A larger clinical study is warranted to further clarify our observation.

  9. Pharmacy Students’ Performance and Perceptions in a Flipped Teaching Pilot on Cardiac Arrhythmias

    PubMed Central

    Ip, Eric J.; Lopes, Ingrid; Rajagopalan, Vanishree

    2014-01-01

    Objective. To implement the flipped teaching method in a 3-class pilot on cardiac arrhythmias and to assess the impact of the intervention on academic performance and student perceptions. Design. An intervention group of 101 first-year pharmacy students, who took the class with the flipped teaching method, were supplied with prerecorded lectures prior to their 3 classes (1 class in each of the following subjects: basic sciences, pharmacology, and therapeutics) on cardiac arrhythmias. Class time was focused on active-learning and case-based exercises. Students then took a final examination that included questions on cardiac arrhythmias. The examination scores of the intervention group were compared to scores of the Spring 2011 control group of 105 first-year students who took the class with traditional teaching methods. An online survey was conducted to assess student feedback from the intervention group. Assessment. The mean examination scores of the intervention group were significantly higher than the mean examination scores of the control group for the cardiac arrhythmia classes in pharmacology (with 89.6 ± 2.0% vs 56.8 ± 2.2%, respectively) and therapeutics (89.2 ± 1.4% vs 73.7 ± 2.1%, respectively). The survey indicated higher student satisfaction for flipped classes with highly rated learning objectives, recordings, and in-class activities. Conclusion. Use of the flipped teaching method in a 3-class pilot on cardiac arrhythmias improved examination scores for 2 of the 3 classes (pharmacology and therapeutics). Student satisfaction was influenced by the quality of the learning objectives, prerecorded lectures, and inclass active-learning activities. PMID:25657372

  10. Postoperative Arrhythmias after Cardiac Surgery: Incidence, Risk Factors, and Therapeutic Management

    PubMed Central

    Cianflone, Domenico

    2014-01-01

    Arrhythmias are a known complication after cardiac surgery and represent a major cause of morbidity, increased length of hospital stay, and economic costs. However, little is known about incidence, risk factors, and treatment of early postoperative arrhythmias. Both tachyarrhythmias and bradyarrhythmias can present in the postoperative period. In this setting, atrial fibrillation is the most common heart rhythm disorder. Postoperative atrial fibrillation is often self-limiting, but it may require anticoagulation therapy and either a rate or rhythm control strategy. However, ventricular arrhythmias and conduction disturbances can also occur. Sustained ventricular arrhythmias in the recovery period after cardiac surgery may warrant acute treatment and long-term preventive strategy in the absence of reversible causes. Transient bradyarrhythmias may be managed with temporary pacing wires placed at surgery, but significant and persistent atrioventricular block or sinus node dysfunction can occur with the need for permanent pacing. We provide a complete and updated review about mechanisms, risk factors, and treatment strategies for the main postoperative arrhythmias. PMID:24511410

  11. Small-conductance Ca2+ -activated K+ channels and cardiac arrhythmias.

    PubMed

    Zhang, Xiao-Dong; Lieu, Deborah K; Chiamvimonvat, Nipavan

    2015-08-01

    Small-conductance Ca2+ -activated K+ (SK, KCa2) channels are unique in that they are gated solely by changes in intracellular Ca2+ and, hence, function to integrate intracellular Ca2+ and membrane potentials on a beat-to-beat basis. Recent studies have provided evidence for the existence and functional significance of SK channels in the heart. Indeed, our knowledge of cardiac SK channels has been greatly expanded over the past decade. Interests in cardiac SK channels are further driven by recent studies suggesting the critical roles of SK channels in human atrial fibrillation, the SK channel as a possible novel therapeutic target in atrial arrhythmias, and upregulation of SK channels in heart failure in animal models and in human heart failure. However, there remain critical gaps in our knowledge. Specifically, blockade of SK channels in cardiac arrhythmias has been shown to be both antiarrhythmic and proarrhythmic. This contemporary review provides an overview of the literature on the role of cardiac SK channels in cardiac arrhythmias and serves as a discussion platform for the current clinical perspectives. At the translational level, development of SK channel blockers as a new therapeutic strategy in the treatment of atrial fibrillation and the possible proarrhythmic effects merit further considerations and investigations.

  12. Clinical Profile of Cardiac Arrhythmias in Children Attending the Out Patient Department of a Tertiary Paediatric Care Centre in Chennai

    PubMed Central

    Sundararajan, Premkumar; Sangaralingam, Thangavelu

    2016-01-01

    Introduction The presentation of symptoms of paediatric arrhythmias vary depending on the age and underlying heart disease. Physical examination of children with important arrhythmias may be entirely normal. Aim Aim is to study the characteristics of cardiac arrhythmias in paediatric patients in a tertiary paediatric care centre in Chennai, India. Materials and Methods The participants (n=60) were from birth to 12 years of age. Patients with sinus arrhythmias, sinus tachycardia and sinus bradycardia were excluded. Proportions of various parameters of interest like clinical features, age and sex distribution and underlying heart disease of children presenting with cardiac arrhythmias were arrived. Statistical analysis was performed using SPSS version 16.0. Results Ventricular ectopics were the most common type of arrhythmias observed in the present study followed by Sinus Node Dysfunction (SND). The most common type of SND was sino atrial arrest. Supra ventricular tachycardia was the most frequently sustained tachyarrhythmia in the present study. An increased association of WPW (Wolf Parkinson White Syndrome) with specific congenital cardiac defects was noted. Conclusion Cardiac arrhythmias in children can present at anytime from fetal life to adolescence and their recognition requires high index of suspicion. While majority of children with arrhythmias have structurally normal heart, they are frequently encountered in children with underlying heart disease. Treatment of paediatric arrhythmias should be guided by the severity of the patient, the structure and function of the heart. PMID:28208963

  13. Central Sympathetic Inhibition: a Neglected Approach for Treatment of Cardiac Arrhythmias?

    PubMed

    Cagnoni, Francesca; Destro, Maurizio; Bontempelli, Erika; Locatelli, Giovanni; Hering, Dagmara; Schlaich, Markus P

    2016-02-01

    Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. Overactivation of the sympathetic nervous system (SNS) plays an important role in the pathogenesis of comorbidities related to AF such as hypertension, congestive heart failure, obesity, insulin resistance, and obstructive sleep apnea. Methods that reduce sympathetic drive, such as centrally acting sympatho-inhibitory agents, have been shown to reduce the incidence of spontaneous or induced atrial arrhythmias, suggesting that neuromodulation may be helpful in controlling AF. Moxonidine acts centrally to reduce activity of the SNS, and clinical trials indicate that this is associated with a decreased AF burden in hypertensive patients with paroxysmal AF and reduced post-ablation recurrence of AF in patients with hypertension who underwent pulmonary vein isolation (PVI). Furthermore, device-based approaches to reduce sympathetic drive, such as renal denervation, have yielded promising results in the prevention and treatment of cardiac arrhythmias. In light of these recent findings, targeting elevated sympathetic drive with either pharmacological or device-based approaches has become a focus of clinical research. Here, we review the data currently available to explore the potential utility of sympatho-inhibitory therapies in the prevention and treatment of cardiac arrhythmias.

  14. The role of acute hyperinsulinemia in the development of cardiac arrhythmias.

    PubMed

    Drimba, László; Döbrönte, Róbert; Hegedüs, Csaba; Sári, Réka; Di, Yin; Németh, Joseph; Szilvássy, Zoltán; Peitl, Barna

    2013-05-01

    Patients with perturbed metabolic control are more prone to develop cardiac rhythm disturbances. The main purpose of the present preclinical study was to investigate the possible role of euglycemic hyperinsulinemia in development of cardiac arrhythmias. Euglycemic hyperinsulinemia was induced in conscious rabbits equipped with a right ventricular pacemaker electrode catheter by hyperinsulinemic euglycemic glucose clamp (HEGC) applying two different rates of insulin infusion (5 and 10 mIU/kg/min) and variable rate of glucose infusion to maintain euglycemia (5.5 ± 0.5 mmol/l). The effect of hyperinsulinemia on cardiac electrophysiological parameters was continuously monitored by means of 12-lead surface ECG recording. Arrhythmia incidence was determined by means of programmed electrical stimulation (PES). The possible role of adrenergic activation was investigated by determination of plasma catecholamine levels and intravenous administration of a beta adrenergic blocking agent, metoprolol. All of the measurements were performed during the steady-state period of HEGC and subsequent to metoprolol administration. Both 5 and 10 mIU/kg/min insulin infusion prolonged significantly QTend, QTc, and Tpeak-Tend intervals. The incidence of ventricular arrhythmias generated by PES was increased significantly by euglycemic hyperinsulinemia and exhibited linear relationship to plasma levels of insulin. No alteration on plasma catecholamine levels could be observed; however, metoprolol treatment restored the prolonged QTend, QTc, and Tpeak-Tend intervals and significantly reduced the hyperinsulinemia-induced increase of arrhythmia incidence. Euglycemic hyperinsulinemia can exert proarrhythmic effect presumably due to the enhancement of transmural dispersion of repolarization. Metoprolol treatment may be of benefit in hyperinsulinemia associated with increased incidence of cardiac arrhythmias.

  15. Control of Cardiac Arrhythmia by Nonlinear Spatiotemporal Delayed Feedback

    NASA Astrophysics Data System (ADS)

    Boroujeni, Forough Rezaei; Vasegh, Nastaran; Sedigh, Ali Khaki

    The dynamic feedback control of the cardiac pacing interval has been widely used to suppress alternans. In this paper, temporally and spatially suppressing the alternans for cardiac tissue consisting of a one-dimensional chain of cardiac units is investigated. The model employed is a nonlinear partial difference equation. The model's fixed points and their stability conditions are determined, and bifurcations and chaos phenomenon have been studied by numerical simulations. The main objective of this paper is to stabilize the unstable fixed point of the model. The proposed approach is nonlinear spatiotemporal delayed feedback, and the appropriate interval for controller feedback gain is calculated using the linear stability analysis. It is proven that the proposed approach is robust with respect to all bifurcation parameter variations. Also, set point tracking is achieved by employing delayed feedback with an integrator. Finally, simulation results are provided to show the effectiveness of the proposed methodology.

  16. Executive Summary: European Heart Rhythm Association Consensus Document on the Management of Supraventricular Arrhythmias

    PubMed Central

    Katritsis, Demosthenes G; Boriani, Giuseppe; Cosio, Francisco G; Jais, Pierre; Hindricks, Gerhard; Josephson, Mark E; Keegan, Roberto; Knight, Bradley P; Kuck, Karl-Heinz; Lane, Deirdre A; Lip, Gregory YH; Malmborg, Helena; Oral, Hakan; Pappone, Carlo; Themistoclakis, Sakis; Wood, Kathryn A.; Young-Hoon, Kim; Lundqvist, Carina Blomström

    2016-01-01

    This paper is an executive summary of the full European Heart Rhythm Association (EHRA) consensus document on the management of supraventricular arrhythmias, published in Europace. It summarises developments in the field and provides recommendations for patient management, with particular emphasis on new advances since the previous European Society of Cardiology guidelines. The EHRA consensus document is available to read in full at http://europace.oxfordjournals.org PMID:28116087

  17. Macrophage-dependent IL-1β production induces cardiac arrhythmias in diabetic mice

    PubMed Central

    Monnerat, Gustavo; Alarcón, Micaela L.; Vasconcellos, Luiz R.; Hochman-Mendez, Camila; Brasil, Guilherme; Bassani, Rosana A.; Casis, Oscar; Malan, Daniela; Travassos, Leonardo H.; Sepúlveda, Marisa; Burgos, Juan Ignacio; Vila-Petroff, Martin; Dutra, Fabiano F.; Bozza, Marcelo T.; Paiva, Claudia N.; Carvalho, Adriana Bastos; Bonomo, Adriana; Fleischmann, Bernd K.; de Carvalho, Antonio Carlos Campos; Medei, Emiliano

    2016-01-01

    Diabetes mellitus (DM) encompasses a multitude of secondary disorders, including heart disease. One of the most frequent and potentially life threatening disorders of DM-induced heart disease is ventricular tachycardia (VT). Here we show that toll-like receptor 2 (TLR2) and NLRP3 inflammasome activation in cardiac macrophages mediate the production of IL-1β in DM mice. IL-1β causes prolongation of the action potential duration, induces a decrease in potassium current and an increase in calcium sparks in cardiomyocytes, which are changes that underlie arrhythmia propensity. IL-1β-induced spontaneous contractile events are associated with CaMKII oxidation and phosphorylation. We further show that DM-induced arrhythmias can be successfully treated by inhibiting the IL-1β axis with either IL-1 receptor antagonist or by inhibiting the NLRP3 inflammasome. Our results establish IL-1β as an inflammatory connection between metabolic dysfunction and arrhythmias in DM. PMID:27882934

  18. Arrhythmias in Patients with Cardiac Implantable Electrical Devices after Implantation of a Left Ventricular Assist Device.

    PubMed

    Rosenbaum, Andrew N; Kremers, Walter K; Duval, Sue; Sakaguchi, Scott; John, Ranjit; Eckman, Peter M

    2016-01-01

    Utilization of continuous-flow left ventricular assist devices (CF-LVADs) for advanced heart failure is increasing, and the role of cardiac implantable electrical devices (CIED) is unclear. Prior studies of the incidence of arrhythmias and shocks are frequently limited by ascertainment. One hundred and seventy-eight patients were examined with a previous CIED who were implanted with a CF-LVAD. Medical history, medications, and CIED data from device interrogations were gathered. A cardiac surgery control group (n = 38) was obtained to control for surgical factors. Several clinically significant events increased after LVAD implantation: treated-zone ventricular arrhythmias (VA; p < 0.01), monitored-zone VA (p < 0.01), antitachycardia pacing (ATP)-terminated episodes (p < 0.01), and shocks (p = 0.01), although administered shocks later decreased (p < 0.01). Presence of a preimplant VA was associated with postoperative VA (odds ratio [OR]: 4.31; confidence interval [CI]: 1.5-12.3, p < 0.01). Relative to cardiac surgery, LVAD patients experienced more perioperative events (i.e., monitored VAs and shocks, p < 0.01 and p = 0.04). Neither implantable cardioverter defibrillator (ICD) shocks before implant nor early or late postimplant arrhythmias or shocks predicted survival (p = 0.07, p = 0.55, and p = 0.55). Our experience demonstrates time-dependent effects on clinically significant arrhythmias after LVAD implantation, including evidence that early LVAD-related arrhythmias may be caused by the unique arrhythmogenic effects of VAD implant.

  19. Cardiac sodium channel palmitoylation regulates channel availability and myocyte excitability with implications for arrhythmia generation

    PubMed Central

    Pei, Zifan; Xiao, Yucheng; Meng, Jingwei; Hudmon, Andy; Cummins, Theodore R.

    2016-01-01

    Cardiac voltage-gated sodium channels (Nav1.5) play an essential role in regulating cardiac electric activity by initiating and propagating action potentials in the heart. Altered Nav1.5 function is associated with multiple cardiac diseases including long-QT3 and Brugada syndrome. Here, we show that Nav1.5 is subject to palmitoylation, a reversible post-translational lipid modification. Palmitoylation increases channel availability and late sodium current activity, leading to enhanced cardiac excitability and prolonged action potential duration. In contrast, blocking palmitoylation increases closed-state channel inactivation and reduces myocyte excitability. We identify four cysteines as possible Nav1.5 palmitoylation substrates. A mutation of one of these is associated with cardiac arrhythmia (C981F), induces a significant enhancement of channel closed-state inactivation and ablates sensitivity to depalmitoylation. Our data indicate that alterations in palmitoylation can substantially control Nav1.5 function and cardiac excitability and this form of post-translational modification is likely an important contributor to acquired and congenital arrhythmias. PMID:27337590

  20. Electrocardiographic Presentation, Cardiac Arrhythmias, and Their Management in β-Thalassemia Major Patients.

    PubMed

    Russo, Vincenzo; Rago, Anna; Papa, Andrea Antonio; Nigro, Gerardo

    2016-07-01

    Beta-thalassemia major (β-TM) is a genetic hemoglobin disorder characterized by an absent synthesis of globin chains that are essential for hemoglobin formation, causing chronic hemolytic anemia. Clinical management of thalassemia major consists in regular long-life red blood cell transfusions and iron chelation therapy to remove iron introduced in excess with transfusions. Iron deposition in combination with inflammatory and immunogenic factors is involved in the pathophysiology of cardiac dysfunction in these patients. Heart failure and arrhythmias, caused by myocardial siderosis, are the most important life-limiting complications of iron overload in beta-thalassemia patients. Cardiac complications are responsible for 71% of global death in the beta-thalassemia major patients. The aim of this review was to describe the most frequent electrocardiographic abnormalities and arrhythmias observed in β-TM patients, analyzing their prognostic impact and current treatment strategies.

  1. Renal denervation for treatment of cardiac arrhythmias: state of the art and future directions.

    PubMed

    Kosiuk, Jedrzej; Hilbert, Sebastian; Pokushalov, Evgeny; Hindricks, Gerhard; Steinberg, Jonathan S; Bollmann, Andreas

    2015-02-01

    It has now been more than a quarter of a century since modulation of the sympathetic nervous system was proposed for the treatment of cardiac arrhythmias of different origins. But it has also been some time since some of the early surgical attempts have been abandoned. With the development of ablation techniques, however, new approaches and targets have been recently introduced that have revolutionized our way of thinking about sympathetic modulation. Renal nerve ablation technology is now being successfully used for the treatment of resistant hypertension, but the indication spectrum might broaden and new therapeutic options might arise in the near future. This review focuses on the possible impact of renal sympathetic system modulation on cardiac arrhythmias, the current evidence supporting this approach, and the ongoing trials of this method in electrophysiological laboratories. We will discuss the potential roles that sympathetic modulation may play in the future.

  2. Cardiac Mechano-Gated Ion Channels and Arrhythmias

    PubMed Central

    Peyronnet, Remi; Nerbonne, Jeanne M.; Kohl, Peter

    2015-01-01

    Mechanical forces will have been omnipresent since the origin of life, and living organisms have evolved mechanisms to sense, interpret and respond to mechanical stimuli. The cardiovascular system in general, and the heart in particular, are exposed to constantly changing mechanical signals, including stretch, compression, bending, and shear. The heart adjusts its performance to the mechanical environment, modifying electrical, mechanical, metabolic, and structural properties over a range of time scales. Many of the underlying regulatory processes are encoded intra-cardially, and are thus maintained even in heart transplant recipients. Although mechano-sensitivity of heart rhythm has been described in the medical literature for over a century, its molecular mechanisms are incompletely understood. Thanks to modern biophysical and molecular technologies, the roles of mechanical forces in cardiac biology are being explored in more detail, and detailed mechanisms of mechano-transduction have started to emerge. Mechano-gated ion channels are cardiac mechano-receptors. They give rise to mechano-electric feedback, thought to contribute to normal function, disease development, and, potentially, therapeutic interventions. In this review, we focus on acute mechanical effects on cardiac electrophysiology, explore molecular candidates underlying observed responses, and discuss their pharmaceutical regulation. From this, we identify open research questions and highlight emerging technologies that may help in addressing them. Cardiac electrophysiology is acutely affected by the heart’s mechanical environment. Mechano-electric feedback affects excitability, conduction, and electrical load, and remains an underestimated player in arrhythmogenesis. The utility of therapeutic interventions targeting acute mechano-electrical transduction is an open field worthy of further study. PMID:26838316

  3. Cardiac Atrophy and Diastolic Dysfunction During and After Long Duration Spaceflight: Functional Consequences for Orthostatic Intolerance, Exercise Capability and Risk for Cardiac Arrhythmias

    NASA Technical Reports Server (NTRS)

    Levine, Benjamin D.; Bungo, Michael W.; Platts, Steven H.; Hamilton, Douglas R.; Johnston, Smith L.

    2009-01-01

    Cardiac Atrophy and Diastolic Dysfunction During and After Long Duration Spaceflight: Functional Consequences for Orthostatic Intolerance, Exercise Capability and Risk for Cardiac Arrhythmias (Integrated Cardiovascular) will quantify the extent of long-duration space flightassociated cardiac atrophy (deterioration) on the International Space Station crewmembers.

  4. The association between HERG gene expression and cardiac arrhythmia disease in children

    PubMed Central

    Fu, Mingyu; Li, Chunli; Wang, Qingwen; Wang, Yan; An, Xinjiang

    2016-01-01

    We explored the possible link between the expression of HERG gene and cardiomyopathy in children. From April 2013 to April 2015, 73 children with cardiac arrhythmia who were treated were enrolled in the present study to serve as the observation group. At the same time, 76 normal individuals were also enrolled as the control group. HERG expression level in the observation group was compared with the control group. To determine the level of HERG gene expression we used fluorescent directional PCR, enzyme immunoassay and western blot analysis. The results showed that HERG mRNA level in the observation group was significantly higher than that of the control group. The level of HERG protein in the observation group was significantly higher as well. In the observation group, HERG expression gradually increased with time during the course of the disease. This result suggested that HERG gene expression was associated with the severity of cardiac arrhythmia in children. HERG expression may be the cause of deterioration in cardiomyopathy. The results have provided a theoretical and practical basis for the diagnosis and treatment of children cardiomyopathy. Thus, we established a correlation between HERG expression and cardiac arrhythmia in children. PMID:28101152

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

    PubMed

    Miao, Fen; Cai, Yun-Peng; Zhang, Yu-Xiao; Li, Ye; Zhang, Yuan-Ting

    2015-01-01

    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.

  6. A Real-Time Cardiac Arrhythmia Classification System with Wearable Sensor Networks

    PubMed Central

    Hu, Sheng; Wei, Hongxing; Chen, Youdong; Tan, Jindong

    2012-01-01

    Long term continuous monitoring of electrocardiogram (ECG) in a free living environment provides valuable information for prevention on the heart attack and other high risk diseases. This paper presents the design of a real-time wearable ECG monitoring system with associated cardiac arrhythmia classification algorithms. One of the striking advantages is that ECG analog front-end and on-node digital processing are designed to remove most of the noise and bias. In addition, the wearable sensor node is able to monitor the patient's ECG and motion signal in an unobstructive way. To realize the real-time medical analysis, the ECG is digitalized and transmitted to a smart phone via Bluetooth. On the smart phone, the ECG waveform is visualized and a novel layered hidden Markov model is seamlessly integrated to classify multiple cardiac arrhythmias in real time. Experimental results demonstrate that the clean and reliable ECG waveform can be captured in multiple stressed conditions and the real-time classification on cardiac arrhythmia is competent to other workbenches. PMID:23112746

  7. A real-time cardiac arrhythmia classification system with wearable sensor networks.

    PubMed

    Hu, Sheng; Wei, Hongxing; Chen, Youdong; Tan, Jindong

    2012-01-01

    Long term continuous monitoring of electrocardiogram (ECG) in a free living environment provides valuable information for prevention on the heart attack and other high risk diseases. This paper presents the design of a real-time wearable ECG monitoring system with associated cardiac arrhythmia classification algorithms. One of the striking advantages is that ECG analog front-end and on-node digital processing are designed to remove most of the noise and bias. In addition, the wearable sensor node is able to monitor the patient's ECG and motion signal in an unobstructive way. To realize the real-time medical analysis, the ECG is digitalized and transmitted to a smart phone via Bluetooth. On the smart phone, the ECG waveform is visualized and a novel layered hidden Markov model is seamlessly integrated to classify multiple cardiac arrhythmias in real time. Experimental results demonstrate that the clean and reliable ECG waveform can be captured in multiple stressed conditions and the real-time classification on cardiac arrhythmia is competent to other workbenches.

  8. Role for the Unfolded Protein Response in Heart Disease and Cardiac Arrhythmias.

    PubMed

    Liu, Man; Dudley, Samuel C

    2015-12-31

    The unfolded protein response (UPR) has been extensively investigated in neurological diseases and diabetes, while its function in heart disease is less well understood. Activated UPR participates in multiple cardiac conditions and can either protect or impair heart function. Recently, the UPR has been found to play a role in arrhythmogenesis during human heart failure by affecting cardiac ion channels expression, and blocking UPR has an antiarrhythmic effect. This review will discuss the rationale for and challenges to targeting UPR in heart disease for treatment of arrhythmias.

  9. Potassium-channel mutations and cardiac arrhythmias--diagnosis and therapy.

    PubMed

    Giudicessi, John R; Ackerman, Michael J

    2012-01-31

    The coordinated generation and propagation of action potentials within cardiomyocytes creates the intrinsic electrical stimuli that are responsible for maintaining the electromechanical pump function of the human heart. The synchronous opening and closing of cardiac Na(+), Ca(2+), and K(+) channels corresponds with the activation and inactivation of inward depolarizing (Na(+) and Ca(2+)) and outward repolarizing (K(+)) currents that underlie the various phases of the cardiac action potential (resting, depolarization, plateau, and repolarization). Inherited mutations in pore-forming α subunits and accessory β subunits of cardiac K(+) channels can perturb the atrial and ventricular action potential and cause various cardiac arrhythmia syndromes, including long QT syndrome, short QT syndrome, Brugada syndrome, and familial atrial fibrillation. In this Review, we summarize the current understanding of the molecular and cellular mechanisms that underlie K(+)-channel-mediated arrhythmia syndromes. We also describe translational advances that have led to the emerging role of genetic testing and genotype-specific therapy in the diagnosis and clinical management of individuals who harbor pathogenic mutations in genes that encode α or β subunits of cardiac K(+) channels.

  10. Sudden infant death syndrome caused by cardiac arrhythmias: only a matter of genes encoding ion channels?

    PubMed

    Sarquella-Brugada, Georgia; Campuzano, Oscar; Cesar, Sergi; Iglesias, Anna; Fernandez, Anna; Brugada, Josep; Brugada, Ramon

    2016-03-01

    Sudden infant death syndrome is the unexpected demise of a child younger than 1 year of age which remains unexplained after a complete autopsy investigation. Usually, it occurs during sleep, in males, and during the first 12 weeks of life. The pathophysiological mechanism underlying the death is unknown, and the lethal episode is considered multifactorial. However, in cases without a conclusive post-mortem diagnosis, suspicious of cardiac arrhythmias may also be considered as a cause of death, especially in families suffering from any cardiac disease associated with sudden cardiac death. Here, we review current understanding of sudden infant death, focusing on genetic causes leading to lethal cardiac arrhythmias, considering both genes encoding ion channels as well as structural proteins due to recent association of channelopathies and desmosomal genes. We support a comprehensive analysis of all genes associated with sudden cardiac death in families suffering of infant death. It allows the identification of the most plausible cause of death but also of family members at risk, providing cardiologists with essential data to adopt therapeutic preventive measures in families affected with this lethal entity.

  11. Periodic Limb Movements during Sleep and Cardiac Arrhythmia in Older Men (MrOS Sleep)

    PubMed Central

    Koo, Brian B.; Mehra, Reena; Blackwell, Terri; Ancoli-Israel, Sonia; Stone, Katie L.; Redline, Susan

    2014-01-01

    Study Objectives: To determine if periodic limb movements during sleep (PLMS) are associated with nocturnal cardiac arrhythmia. Methods: 2,793 community-dwelling older men underwent polysomnography with measurement of limb movements and EKG. Logistic regression assessed association of periodic limb movement index and periodic limb movement arousal index with arrhythmia including atrial fibrillation and non-sustained ventricular tachycardia detected by polysomnography. Models were adjusted for age, race, cardiovascular risk factors, and clinic site. Secondary analyses were subset to men without calcium channel/β-adrenergic medication usage, and stratified by congestive heart failure or myocardial infarction history. Results: In the overall cohort, periodic limb movement index, and periodic limb movement arousal index were not associated with ventricular or atrial arrhythmia after considering potential confounders. In men not taking calcium channel/β-blocking medication, increased adjusted odds of non-sustained ventricular tachycardia were observed for periodic limb movement index (OR = 1.30 per SD increase; 95% CI 1.00, 1.68) and periodic limb movement arousal index (OR = 1.29 per SD increase; 95% CI 1.03, 1.62). In men with CHF or MI, there was a suggested association of atrial fibrillation with periodic limb movement index (OR = 1.29, 95% CI 0.96, 1.73 per SD increase; p = 0.09) or periodic limb movement arousal index (OR = 1.21, 95% CI 0.94, 1.57 per SD increase; p = 0.14), although results were not statistically significant. Conclusions: There is not an association between PLMS and cardiac arrhythmia in all older men but in subsets of men, particularly those with structural heart disease and not on calcium channel or β-adrenergic medication, cardiac arrhythmia does associate with PLMS. Citation: Koo BB; Mehra R; Blackwell T; Ancoli-Israel S; Stone KL; Redline S; for the Osteoporotic Fractures in Men (MrOS) Study Group. Periodic limb movements during sleep and

  12. Trends in Reporting Methadone-Associated Cardiac Arrhythmia, 1997–2011

    PubMed Central

    Kao, David; Bartelson, Becki Bucher; Khatri, Vaishali; Dart, Richard; Mehler, Philip S.; Katz, David; Krantz, Mori J.

    2013-01-01

    Background: Long-acting opioids are a leading cause of accidental death in the United States, and methadone is associated with greater mortality rates. Whether this increase is related to the proarrhythmic properties of methadone is unclear. Objective: To describe methadone-associated arrhythmia events reported in the U.S. Food and Drug Administration Adverse Event Reporting System (FAERS). Design: Description of national adverse event registry data before and after publication of a 2002 report describing an association between methadone and arrhythmia. Setting: FAERS, November 1997 and June 2011. Patients: Adults with QTc prolongation or torsade de pointes and ventricular arrhythmia or cardiac arrest. Measurements: FAERS reports before and after the 2002 report. Results: 1646 cases of ventricular arrhythmia or cardiac arrest and 379 cases of QTc prolongation or torsade de pointes were associated with methadone. Monthly reports of QTc prolongation or torsade de pointes increased from a mean of 0.3 (95% CI, 0.1 to 0.5) before the 2002 publication to a mean of 3.5 (CI, 2.5 to 4.8) after it. After 2000, methadone was the second-most common primary suspect in cases of QTc prolongation or torsade de pointes after dofetilide (a known proarrhythmic drug) and was associated with disproportionate reporting similar to that of antiarrhythmic agents known to promote torsade de pointes. Antiretroviral drugs for HIV were the most common coadministered drugs. Limitation: Reports to FAERs are voluntary and selective, and incidence rates cannot be determined from spontaneously reported data. Conclusion: Since 2002, reports to FAERS of methadone-associated arrhythmia have increased substantially and are disproportionately represented relative to other events with the drug. Coadministration of methadone with antiretrovirals in patients with HIV may pose particular risk. Primary Funding Source: Colorado Clinical and Translational Sciences Institute, National Institutes of Health, and

  13. When the clock strikes: Modeling the relation between circadian rhythms and cardiac arrhythmias

    NASA Astrophysics Data System (ADS)

    Seenivasan, Pavithraa; Menon, Shakti N.; Sridhar, S.; Sinha, Sitabhra

    2016-10-01

    It has recently been observed that the occurrence of sudden cardiac death has a close statistical relationship with the time of day, viz., ventricular fibrillation is most likely to occur between 12am-6am, with 6pm-12am being the next most likely period. Consequently there has been significant interest in understanding how cardiac activity is influenced by the circadian clock, i.e., temporal oscillations in physiological activity with a period close to 24 hours and synchronized with the day-night cycle. Although studies have identified the genetic basis of circadian rhythm at the intracellular level, the mechanisms by which they influence cardiac pathologies are not yet fully understood. Evidence has suggested that diurnal variations in the conductance properties of ion channel proteins that govern the excitation dynamics of cardiac cells may provide the crucial link. In this paper, we investigate the relationship between the circadian rhythm as manifested in modulations of ion channel properties and the susceptibility to cardiac arrhythmias by using a mathematical model that describes the electrical activity in ventricular tissue. We show that changes in the channel conductance that lead to extreme values for the duration of action potentials in cardiac cells can result either in abnormally high-frequency reentrant activity or spontaneous conduction block of excitation waves. Both phenomena increase the likelihood of wavebreaks that are known to initiate potentially life- threatening arrhythmias. Thus, disruptive cardiac excitation dynamics are most likely to occur in time-intervals of the day-night cycle during which the channel properties are closest to these extreme values, providing an intriguing relation between circadian rhythms and cardiac pathologies.

  14. Carbon Monoxide Induces Cardiac Arrhythmia via Induction of the Late Na+ Current

    PubMed Central

    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.

    2012-01-01

    Rationale: 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. Objectives: To understand the cellular basis of CO-induced arrhythmias and to indentify an effective therapeutic approach. Methods: Patch-clamp electrophysiology and confocal Ca2+ 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. Measurements and Main Results: CO increased the sustained (late) component of the inward Na+ current, resulting in prolongation of the action potential and the associated intracellular Ca2+ 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, Nav1.5. 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. Conclusions: Our data indicate that the proarrhythmic effects of CO arise from activation of NO synthase, leading to NO-mediated nitrosylation of NaV1.5 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. PMID:22822026

  15. Non-invasive cardiac mapping in clinical practice: Application to the ablation of cardiac arrhythmias.

    PubMed

    Dubois, Rémi; Shah, Ashok J; Hocini, Mélèze; Denis, Arnaud; Derval, Nicolas; Cochet, Hubert; Sacher, Frédéric; Bear, Laura; Duchateau, Josselin; Jais, Pierre; Haissaguerre, Michel

    2015-01-01

    Ten years ago, electrocardiographic imaging (ECGI) started to demonstrate its efficiency in clinical settings. The initial application to localize focal ventricular arrhythmias such as ventricular premature beats was probably the easiest to challenge and validates the concept. Our clinical experience in using this non-invasive mapping technique to identify the sources of electrical disorders and guide catheter ablation of atrial arrhythmias (premature atrial beat, atrial tachycardia, atrial fibrillation), ventricular arrhythmias (premature ventricular beats) and ventricular pre-excitation (Wolff-Parkinson-White syndrome) is described here.

  16. Cardiac Spliced BIN1 Folds T-tubule Membrane, Controlling Ion Flux and Limiting Arrhythmia

    PubMed Central

    Hong, TingTing; Yang, Huanghe; Zhang, Shan-Shan; Cho, Hee Cheol; Kalashnikova, Mariya; Sun, Baiming; Zhang, Hao; Bhargava, Anamika; Grabe, Michael; Olgin, Jeffrey; Gorelik, Julia; Marbán, Eduardo; Jan, Lily Y.; Shaw, Robin M.

    2014-01-01

    Cardiomyocyte T-tubules are important for regulating ionic flux. Bridging Integrator 1 (BIN1) is a T-tubule protein associated with calcium channel trafficking that is down-regulated in failing hearts. Here we find that cardiac T-tubules normally contain dense protective inner membrane folds that are formed by a cardiac spliced isoform of BIN1. In mice with cardiac Bin1 deletion, T-tubule folding is decreased which does not change overall cardiomyocyte morphology, but frees diffusion of local extracellular calcium and potassium ions, prolonging action potential duration, and increasing susceptibility to ventricular arrhythmias. We also find that T-tubule inner folds are rescued only by the BIN1 isoform BIN1+13+17, which promotes N-WASP dependent actin polymerization to stabilize T-tubule membrane at cardiac Z-discs. In conclusion, BIN1+13+17 recruits actin to fold T-tubule membrane, creating a fuzzy space that protectively restricts ionic flux. When BIN1+13+17 is decreased, as occurs in acquired cardiomyopathy, T-tubule morphology is altered and arrhythmias can result. PMID:24836577

  17. Human sinus arrhythmia as an index of vagal cardiac outflow

    NASA Technical Reports Server (NTRS)

    Eckberg, D. L.

    1983-01-01

    The human central vagal mechanisms were investigated by measuring the intervals between heartbeats during controlled breathing (at breathing intervals of 2.5-10 s and nominal tidal volumes of 1000 and 1500 ml) in six young men and women. It was found that as the breathing interval increased, the longest heart periods became longer, the shortest heart periods became shorter, and the peak-valley P-P intervals increased asymptotically. Peak-valley intervals also increased in proportion to tidal volume, although this influence was small. The phase angles between heart period changes and respiration were found to vary as linear functions of breathing interval. Heart period shortening began in inspiration at short breathing intervals and in expiration at long breathing intervals, while heart period lengthening began in early expiration at all breathing intervals studied. It is concluded that a close relationship exists between variations of respiratory depth and interval and the quantity, periodicity, and timing of vagal cardiac outflow in conscious humans. The results indicate that at usual breathing rates, phasic respiration-related changes of vagal motoneuron activity begin in expiration, progress slowly, and are incompletely expressed at fast breathing ratges.

  18. Inhibition of serum and glucocorticoid regulated kinase-1 as novel therapy for cardiac arrhythmia disorders.

    PubMed

    Bezzerides, Vassilios J; Zhang, Aifeng; Xiao, Ling; Simonson, Bridget; Khedkar, Santosh A; Baba, Shiro; Ottaviano, Filomena; Lynch, Stacey; Hessler, Katherine; Rigby, Alan C; Milan, David; Das, Saumya; Rosenzweig, Anthony

    2017-03-23

    Alterations in sodium flux (INa) play an important role in the pathogenesis of cardiac arrhythmias and may also contribute to the development of cardiomyopathies. We have recently demonstrated a critical role for the regulation of the voltage-gated sodium channel NaV1.5 in the heart by the serum and glucocorticoid regulated kinase-1 (SGK1). Activation of SGK1 in the heart causes a marked increase in both the peak and late sodium currents leading to prolongation of the action potential duration and an increased propensity to arrhythmia. Here we show that SGK1 directly regulates NaV1.5 channel function, and genetic inhibition of SGK1 in a zebrafish model of inherited long QT syndrome rescues the long QT phenotype. Using computer-aided drug discovery coupled with in vitro kinase assays, we identified a novel class of SGK1 inhibitors. Our lead SGK1 inhibitor (5377051) selectively inhibits SGK1 in cultured cardiomyocytes, and inhibits phosphorylation of an SGK1-specific target as well as proliferation in the prostate cancer cell line, LNCaP. Finally, 5377051 can reverse SGK1's effects on NaV1.5 and shorten the action potential duration in induced pluripotent stem cell (iPSC)-derived cardiomyocytes from a patient with a gain-of-function mutation in Nav 1.5 (Long QT3 syndrome). Our data suggests that SGK1 inhibitors warrant further investigation in the treatment of cardiac arrhythmias.

  19. Categories of Arrhythmias

    MedlinePlus

    ... previous page En español Aneurysms and Dissections Angina Arrhythmia Bundle Branch Block Cardiomyopathy Carotid Artery Disease Chronic ... Cardiac Arrest Valve Disease Vulnerable Plaque Categories of Arrhythmias Arrhythmias are generally divided into two categories: ventricular ...

  20. Cardiac Resynchronization Therapy Defibrillator Treatment in a Child with Heart Failure and Ventricular Arrhythmia

    PubMed Central

    Kim, Hak Ju; Cho, Sungkyu; Kim, Woong-Han

    2016-01-01

    Cardiac resynchronization therapy (CRT) is a new treatment for refractory heart failure. However, most patients with heart failure treated with CRT are adults, middle-aged or older with idiopathic or ischemic dilated cardiomyopathy. We treated a 12-year-old boy, who was transferred after cardiac arrest, with dilated cardiomyopathy, left bundle-branch block, and ventricular tachycardia. We performed cardiac resynchronization therapy with a defibrillator (CRT-D). After CRT-D, left ventricular ejection fraction improved from 22% to 44% assessed by echocardiogram 1 year postoperatively. On electrocardiogram, QRS duration was shortened from 206 to 144 ms. The patient’s clinical symptoms also improved. For pediatric patients with refractory heart failure and ventricular arrhythmia, CRT-D could be indicated as an effective therapeutic option. PMID:27525239

  1. Ranolazine: Electrophysiologic Effect, Efficacy, and Safety in Patients with Cardiac Arrhythmias.

    PubMed

    Shenasa, Mohammad; Assadi, Hamid; Heidary, Shahriar; Shenasa, Hossein

    2016-06-01

    Ranolazine is currently approved as an antianginal agent in patients with chronic angina (class IIA). Ranolazine exhibits antiarrhythmic effects that are related to its multichannel blocking effect, predominantly inhibition of late sodium (late INa) current and the rapid potassium rectifier current (IKr), as well as ICa, late ICa, and INa-Ca. It also suppresses the early and delayed after depolarizations. Ranolazine is effective in the suppression of atrial and ventricular arrhythmias (off-label use) without significant proarrhythmic effect. Currently, ongoing trials are evaluating the efficacy and safety of ranolazine in patients with cardiac arrhythmias; preliminary results suggest that ranolazine, when used alone or in combination with dronedarone, is safe and effective in reducing atrial fibrillation. Ranolazine is not currently approved by the US Food and Drug Administration as an antiarrhythmic agent.

  2. Alk7 Depleted Mice Exhibit Prolonged Cardiac Repolarization and Are Predisposed to Ventricular Arrhythmia

    PubMed Central

    Ying, Shaozhen; Cao, Hong; Hu, He; Wang, Xin; Tang, Yanhong; Huang, Congxin

    2016-01-01

    We aimed to investigate the role of activin receptor-like kinase (ALK7) in regulating cardiac electrophysiology. Here, we showed that Alk7-/- mice exhibited prolonged QT intervals in telemetry ECG recordings. Furthermore, Langendorff-perfused Alk7-/- hearts had significantly longer action potential duration (APD) and greater incidence of ventricular arrhythmia (AV) induced by burst pacing. Using whole-cell patch clamp, we found that the densities of repolarizing K+ currents Ito and IK1 were profoundly reduced in Alk7-/- ventricular cardiomyocytes. Mechanistically, the expression of Kv4.2 (a major subunit of Ito carrying channel) and KCHIP2 (a key accessory subunit of Ito carrying channel), was markedly decreased in Alk7-/- hearts. These findings suggest that endogenous expression of ALK7 is necessary to maintain repolarizing K+ currents in ventricular cardiomyocytes, and finally prevent action potential prolongation and ventricular arrhythmia. PMID:26882027

  3. Cardiac arrhythmias as the initial manifestation of adult primary Sjögren's syndrome: a case report and literature review.

    PubMed

    Liang, Minrui; Bao, Liwen; Xiong, Nanqing; Jin, Bo; Ni, Huanchun; Zhang, Jinjin; Zou, Hejian; Luo, Xinping; Li, Jian

    2015-09-01

    Two middle-aged female patients presenting with heart palpitation and electrocardiogram revealed complex cardiac arrhythmias. A review of systems was positive for dry mouth and transient arthralgia, while laboratory and instrumental tests enabled us to make the diagnosis of primary Sjögren's syndrome (pSS). Cardiac electrophysiology revealed atrioventricular node dysfunction and impaired intraventricular conduction. Prednisone therapy induced a significant improvement in symptoms and electrocardiographic readings. The diagnosis of pSS should be considered in a patient presenting with complex cardiac arrhythmias.

  4. Cardiac arrhythmias in obstructive sleep apnea (from the Akershus Sleep Apnea Project).

    PubMed

    Namtvedt, Silje K; Randby, Anna; Einvik, Gunnar; Hrubos-Strøm, Harald; Somers, Virend K; Røsjø, Helge; Omland, Torbjørn

    2011-10-15

    Increased prevalence of cardiac arrhythmias has been reported in patients with severe obstructive sleep apnea (OSA), but this may not be generalizable to patients from the general population with a milder form of the condition. The aim of this study was to assess the association between cardiac arrhythmias and OSA of mainly mild and moderate severity. In total, 486 subjects (mean age 49 years, 55% men) recruited from a population-based study in Norway underwent polysomnography for OSA assessment and Holter recordings for arrhythmia assessment. Of these, 271 patients were diagnosed with OSA (apnea-hypopnea index [AHI] ≥5, median AHI 16.8, quartiles 1 to 3 8.9 to 32.6). Mean nadir oxygen saturations were 82% and 89% in patients with and without OSA, respectively. Ventricular premature complexes (≥5/hour) were more prevalent in subjects with OSA compared to subjects without OSA (median AHI 1.4, quartiles 1 to 3 0.5 to 3.0) during the night (12.2% vs 4.7%, p = 0.005) and day (14% vs 5.1%, p = 0.002). In multivariate analysis after adjusting for relevant confounders, AHI was independently associated with an increased prevalence of ventricular premature complexes at night (odds ratio per 1-U increase of log-transformed AHI 1.5, 95% confidence interval 1.1 to 2.0, p = 0.008) and during the day (odds ratio 1.37, 95% confidence interval 1.0 to 1.8, p = 0.035). In conclusion, the prevalence of ventricular premature complexes is increased in middle-aged patients with mainly mild or moderate OSA, suggesting an association between OSA and ventricular arrhythmias even in mild OSA.

  5. ATP-sensitive potassium channel modulators and cardiac arrhythmias: an update.

    PubMed

    Muntean, Danina M; Kiss, Loránd; Jost, Norbert; Baczko, István

    2015-01-01

    Ischemia and heart failure-related cardiac arrhythmias, both atrial (e.g., atrial fibrillation) and ventricular (e.g., malignant tachyarrhythmias) represent a leading cause of morbidity and mortality worldwide. Despite the progress made in the last decade in understanding their pathophysiological mechanisms there is still an unmet need for safer and more efficacious pharmacological treatment, especially when considering the drawbacks and complications of implantable devices. Cardiac ATP-sensitive potassium channels located in the sarcolemmal membrane (sarcKATP) and the inner mitochondrial membrane (mitoKATP) have emerged as crucial controllers of several key cellular functions. In the past three decades a tremendous amount of research led to their structural and functional characterization unveiling both a protective role in cardiac adaptive responses to metabolic stress and a seemingly paradoxical role in promoting as well as protecting against atrial and ventricular arrhythmias. On the other hand, several KATP inhibitors have emerged as potential ischemia selective antiarrhythmic drugs. In this respect, cardioselective, chamber specific and combined sarcKATP and mitoKATP modulators currently represent a promising field for drug development.

  6. Arrhythmia and cardiac defects are a feature of spinal muscular atrophy model mice.

    PubMed

    Heier, Christopher R; Satta, Rosalba; Lutz, Cathleen; DiDonato, Christine J

    2010-10-15

    Proximal spinal muscular atrophy (SMA) is the leading genetic cause of infant mortality. Traditionally, SMA has been described as a motor neuron disease; however, there is a growing body of evidence that arrhythmia and/or cardiomyopathy may present in SMA patients at an increased frequency. Here, we ask whether SMA model mice possess such phenotypes. We find SMA mice suffer from severe bradyarrhythmia characterized by progressive heart block and impaired ventricular depolarization. Echocardiography further confirms functional cardiac deficits in SMA mice. Additional investigations show evidence of both sympathetic innervation defects and dilated cardiomyopathy at late stages of disease. Based upon these data, we propose a model in which decreased sympathetic innervation causes autonomic imbalance. Such imbalance would be characterized by a relative increase in the level of vagal tone controlling heart rate, which is consistent with bradyarrhythmia and progressive heart block. Finally, treatment with the histone deacetylase inhibitor trichostatin A, a drug known to benefit phenotypes of SMA model mice, produces prolonged maturation of the SMA heartbeat and an increase in cardiac size. Treated mice maintain measures of motor function throughout extended survival though they ultimately reach death endpoints in association with a progression of bradyarrhythmia. These data represent the novel identification of cardiac arrhythmia as an early and progressive feature of murine SMA while providing several new, quantitative indices of mouse health. Together with clinical cases that report similar symptoms, this reveals a new area of investigation that will be important to address as we move SMA therapeutics towards clinical success.

  7. Downregulation of connexin43 by microRNA-130a in cardiomyocytes results in cardiac arrhythmias.

    PubMed

    Osbourne, Appledene; Calway, Tyler; Broman, Michael; McSharry, Saoirse; Earley, Judy; Kim, Gene H

    2014-09-01

    MicroRNAs (miRNAs) are now recognized as critical regulators of diverse physiological and pathological processes; however, studies of miRNAs and arrhythmogenesis remain sparse. Connexin43 (Cx43), a major cardiac gap junction protein, has elicited great interest in its role in arrhythmias. Additionally, Cx43 was a potential target for miR-130a as predicted by several computational algorithms. This study investigates the effect of miR-130a overexpression in the adult heart and its effect on cardiac rhythm. Using a cardiac-specific inducible system, transgenic mice demonstrated both atrial and ventricular arrhythmias. We performed ventricular-programmed electrical stimulation and found that the αMHC-miR130a mice developed sustained ventricular tachycardia beginning 6weeks after overexpression. Western blot analysis demonstrated a steady decline in Cx43 after 2weeks of overexpression with over a 90% reduction in Cx43 levels by 10weeks. Immunofluorescent staining confirmed a near complete loss of Cx43 throughout the heart. To validate Cx43 as a direct target of miR-130a, we performed in vitro target assays in 3T3 fibroblasts and HL-1 cardiomyocytes, both known to endogenously express miR-130a. Using a luciferase reporter fused to the 3'UTR of Cx43, we found a 52.9% reduction in luciferase activity in 3T3 cells (p<0.0001) and a 47.6% reduction in HL-1 cells (p=0.0056) compared to controls. Addition of an antisense miR-130a inhibitor resulted in a loss of inhibitory activity of the Cx43 3'UTR reporter. We have identified an unappreciated role for miR-130a as a direct regulator of Cx43. Overexpression of miR-130a may contribute importantly to gap junction remodeling and to the pathogenesis of atrial and ventricular arrhythmias.

  8. Therapeutic hypothermia increases the risk of cardiac arrhythmia for perinatal hypoxic ischaemic encephalopathy: A meta-analysis

    PubMed Central

    2017-01-01

    Objective To determine whether therapeutic hypothermia after hypoxic ischaemic encephalopathy (HIE) in neonates increases the risk of cardiac arrhythmia during intervention. Design A meta-analysis was conducted using a fixed-effect model. Risk ratios, risk differences, and 95% confidence intervals, were measured. Data sources Studies identified from the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, Google Scholar, previous reviews, and abstracts from onset to August, 2016. Review methods Reports that compared therapeutic hypothermia with normal care for neonates with HIE and that included data on safety or cardiac arrhythmia, which is of interest to patients and clinicians, were selected. Results We found seven trials, encompassing 1322 infants that included information on safety or cardiac arrhythmia during intervention. Therapeutic hypothermia considerably increased the combined rate of cardiac arrhythmia in the seven trials (risk ratio 2.42, 95% confidence interval 1.23 to 4.76. p = 0.01; risk difference 0.02, 95% CI 0.01 to 0.04) during intervention. Conclusions In infants with hypoxic ischaemic encephalopathy, therapeutic hypothermia is associated with a consistent increase in cardiac arrhythmia during intervention. PMID:28273115

  9. Influence of ambient temperature and diurnal temperature range on incidence of cardiac arrhythmias

    NASA Astrophysics Data System (ADS)

    Kim, Jayeun; Kim, Ho

    2017-03-01

    We investigated the association between ambient temperature and diurnal temperature range (DTR) and the exacerbation of arrhythmia symptoms, using data from 31,629 arrhythmia-related emergency department (ED) visits in Seoul, Korea. Linear regression analyses with allowances for over-dispersion were applied to temperature variables and ED visits, adjusted for various environmental factors. The effects were expressed as percentage changes in the risk of arrhythmia-related ED visits up to 5 days later, with 95 % confidence intervals (CI), per 1 °C increase in DTR and 1 °C decrease in mean temperature. The overall risk of ED visits increased by 1.06 % (95 % CI 0.39 %, 1.73 %) for temperature and by 1.84 % (0.34, 3.37 %) for DTR. A season-specific effect was detected for temperature during both fall (1.18 % [0.01, 2.37 %]) and winter (0.87 % [0.07, 1.67 %]), and for DTR during spring (3.76 % [0.34, 7.29 %]). Females were more vulnerable, with 1.57 % [0.56, 2.59 %] and 3.84 % [1.53, 6.20 %] for the changes in temperature and DTR, respectively. An age-specific effect was detected for DTR, with 3.13 % [0.95, 5.36 %] for age ≥ 65 years, while a greater increased risk with temperature decrease was observed among those aged <65 (1.08 % [0.17, 2.00 %]) than among those aged ≥65 (1.02 % [0.06, 1.99 %]). Cardiac arrest was inversely related with temperature (1.61 % [0.46, 2.79 %]), while other cardiac arrhythmias depended more on the change in DTR (4.72 % [0.37, 9.26 %]). These findings provide evidence that low-temperature and elevated DTR influence the occurrence of arrhythmia exacerbations or symptoms, suggesting a possible strategy for reducing risk by encouraging vulnerable populations to minimize exposure.

  10. Influence of ambient temperature and diurnal temperature range on incidence of cardiac arrhythmias

    NASA Astrophysics Data System (ADS)

    Kim, Jayeun; Kim, Ho

    2016-08-01

    We investigated the association between ambient temperature and diurnal temperature range (DTR) and the exacerbation of arrhythmia symptoms, using data from 31,629 arrhythmia-related emergency department (ED) visits in Seoul, Korea. Linear regression analyses with allowances for over-dispersion were applied to temperature variables and ED visits, adjusted for various environmental factors. The effects were expressed as percentage changes in the risk of arrhythmia-related ED visits up to 5 days later, with 95 % confidence intervals (CI), per 1 °C increase in DTR and 1 °C decrease in mean temperature. The overall risk of ED visits increased by 1.06 % (95 % CI 0.39 %, 1.73 %) for temperature and by 1.84 % (0.34, 3.37 %) for DTR. A season-specific effect was detected for temperature during both fall (1.18 % [0.01, 2.37 %]) and winter (0.87 % [0.07, 1.67 %]), and for DTR during spring (3.76 % [0.34, 7.29 %]). Females were more vulnerable, with 1.57 % [0.56, 2.59 %] and 3.84 % [1.53, 6.20 %] for the changes in temperature and DTR, respectively. An age-specific effect was detected for DTR, with 3.13 % [0.95, 5.36 %] for age ≥ 65 years, while a greater increased risk with temperature decrease was observed among those aged <65 (1.08 % [0.17, 2.00 %]) than among those aged ≥65 (1.02 % [0.06, 1.99 %]). Cardiac arrest was inversely related with temperature (1.61 % [0.46, 2.79 %]), while other cardiac arrhythmias depended more on the change in DTR (4.72 % [0.37, 9.26 %]). These findings provide evidence that low-temperature and elevated DTR influence the occurrence of arrhythmia exacerbations or symptoms, suggesting a possible strategy for reducing risk by encouraging vulnerable populations to minimize exposure.

  11. Feasibility Study on Cardiac Arrhythmia Ablation Using High-Energy Heavy Ion Beams

    NASA Astrophysics Data System (ADS)

    Lehmann, H. Immo; Graeff, Christian; Simoniello, Palma; Constantinescu, Anna; Takami, Mitsuru; Lugenbiel, Patrick; Richter, Daniel; Eichhorn, Anna; Prall, Matthias; Kaderka, Robert; Fiedler, Fine; Helmbrecht, Stephan; Fournier, Claudia; Erbeldinger, Nadine; Rahm, Ann-Kathrin; Rivinius, Rasmus; Thomas, Dierk; Katus, Hugo A.; Johnson, Susan B.; Parker, Kay D.; Debus, Jürgen; Asirvatham, Samuel J.; Bert, Christoph; Durante, Marco; Packer, Douglas L.

    2016-12-01

    High-energy ion beams are successfully used in cancer therapy and precisely deliver high doses of ionizing radiation to small deep-seated target volumes. A similar noninvasive treatment modality for cardiac arrhythmias was tested here. This study used high-energy carbon ions for ablation of cardiac tissue in pigs. Doses of 25, 40, and 55 Gy were applied in forced-breath-hold to the atrioventricular junction, left atrial pulmonary vein junction, and freewall left ventricle of intact animals. Procedural success was tracked by (1.) in-beam positron-emission tomography (PET) imaging; (2.) intracardiac voltage mapping with visible lesion on ultrasound; (3.) lesion outcomes in pathohistolgy. High doses (40–55 Gy) caused slowing and interruption of cardiac impulse propagation. Target fibrosis was the main mediator of the ablation effect. In irradiated tissue, apoptosis was present after 3, but not 6 months. Our study shows feasibility to use high-energy ion beams for creation of cardiac lesions that chronically interrupt cardiac conduction.

  12. Feasibility Study on Cardiac Arrhythmia Ablation Using High-Energy Heavy Ion Beams

    PubMed Central

    Lehmann, H. Immo; Graeff, Christian; Simoniello, Palma; Constantinescu, Anna; Takami, Mitsuru; Lugenbiel, Patrick; Richter, Daniel; Eichhorn, Anna; Prall, Matthias; Kaderka, Robert; Fiedler, Fine; Helmbrecht, Stephan; Fournier, Claudia; Erbeldinger, Nadine; Rahm, Ann-Kathrin; Rivinius, Rasmus; Thomas, Dierk; Katus, Hugo A.; Johnson, Susan B.; Parker, Kay D.; Debus, Jürgen; Asirvatham, Samuel J.; Bert, Christoph; Durante, Marco; Packer, Douglas L.

    2016-01-01

    High-energy ion beams are successfully used in cancer therapy and precisely deliver high doses of ionizing radiation to small deep-seated target volumes. A similar noninvasive treatment modality for cardiac arrhythmias was tested here. This study used high-energy carbon ions for ablation of cardiac tissue in pigs. Doses of 25, 40, and 55 Gy were applied in forced-breath-hold to the atrioventricular junction, left atrial pulmonary vein junction, and freewall left ventricle of intact animals. Procedural success was tracked by (1.) in-beam positron-emission tomography (PET) imaging; (2.) intracardiac voltage mapping with visible lesion on ultrasound; (3.) lesion outcomes in pathohistolgy. High doses (40–55 Gy) caused slowing and interruption of cardiac impulse propagation. Target fibrosis was the main mediator of the ablation effect. In irradiated tissue, apoptosis was present after 3, but not 6 months. Our study shows feasibility to use high-energy ion beams for creation of cardiac lesions that chronically interrupt cardiac conduction. PMID:27996023

  13. Cardiac arrhythmia and ischaemic events after combination chemotherapy for testicular cancer.

    PubMed

    Villani, F; Misrachi, D; Galimberti, M

    1994-11-01

    The aim of the present investigation was to evaluate the type and the incidence of cardiac arrhythmias and ischaemic events in patients suffering from testicular cancer and submitted to combination chemotherapy with cisplatin, bleomycin and vinblastine (PVB) or etoposide (PEB). Forty-seven patients took part in the study; 23 were treated with PVB and 24 with PEB. Holter monitoring was performed in each patient before chemotherapy and on the 1st, 2nd and 5th day of the first cycle of drug administration. The results showed that combination chemotherapy with PVB or PEB was accompanied by the appearance of, or an increase in, the incidence of supraventricular ectopic beats. No significant difference was found between the two groups. No significant conduction disturbances were recorded. These results show that combination chemotherapy with PVB or PEB, at least during the first cycle, has no significant ventricular arrhythmogenic or ischaemic potency in young people with no history of cardiac disease.

  14. High Patient Satisfaction with Deep Sedation for Catheter Ablation of Cardiac Arrhythmia.

    PubMed

    Münkler, Paula; Attanasio, Philipp; Parwani, Abdul Shokor; Huemer, Martin; Boldt, Leif-Hendrik; Haverkamp, Wilhelm; Wutzler, Alexander

    2017-02-27

    Patients' satisfaction with invasive procedures largely relies on periprocedural perception of pain and discomfort. The necessity for intraprocedural sedation during catheter ablation of cardiac arrhythmias for technical reasons is widely accepted, but data on patients' experience of pain and satisfaction with the procedural sedation are scarce. We have assessed patients' pain and discomfort during and after the procedure using a standardized questionnaire. One-hundred seventeen patients who underwent catheter ablation answered a standardized questionnaire on periprocedural perception of pain and discomfort after different anesthetic protocols with propofol/midazolam with and without additional piritramide and ketamine/midazolam. Patients report a high level of satisfaction with periprocedural sedation with 83% judging sedation as good or very good. The majority of patients was unconscious of the whole procedure and did not recollect experiencing pain. Procedural pain was reported by 7.7% of the patients and 16% reported adverse effects, e.g. postprocedural nausea and episodes of headache. The results of our study show, that deep sedation during catheter ablation of cardiac arrhythmias is generally well tolerated and patients are satisfied with the procedure. Yet, a number of patients reports pain or adverse events. Therefore, studies comparing different sedation strategies should be conducted in order to optimize sedation and analgesia. This article is protected by copyright. All rights reserved.

  15. A Field Study of the Effects of Traffic Noise on Heart Rate and Cardiac Arrhythmia During Sleep

    NASA Astrophysics Data System (ADS)

    Carter, N. L.; Ingham, P.; Tran, K.; Hunyor, S. N.

    1994-01-01

    The aim of this study was to test the hypothesis that traffic noise could increase heart rate, and the frequency or severity of cardiac arrhythmias in susceptible people while asleep. Physiological indicators of sleep, electrocardiograph, and respiration and blood oxygen saturation were monitored continuously overnight in seven elderly men living on a busy road. Continuous recordings of the noise outdoors, at the facade, and indoors in the bedrooms, and video recordings of the traffic were made, simultaneously with the physiological measurements. LAeq, LAmax, LApk , LA90, LA10 and LA1 were measured in each 20 s interval, and noise events exceeding 70 dB(A) outdoors and 50 dB(A) indoors for 2 s or longer were logged. Between 03:00 and 05:00 hours, 65% of the traffic consisted of heavy vehicles. With windows open slightly, indoor and outdoor noise exceeded all local, and internationally recommended criteria for adequate sleep by a wide margin. Cardiac arrhythmia occurred during sleep in four of the men. Heart rate and frequency of cardiac arrhythmia were not correlated with indoor LAeq , LApk or LA1, in stage 2, stage 4 and REM sleep. Two of the four subjects with cardiac arrhythmia showed a significant association ( p < 0·05), predominantly in stage 4 sleep, between single indoor noise events and the frequency of cardiac ectopic beats 20-40 s later.

  16. [Electrical cardioversion in the treatment of cardiac arrhythmias during pregnancy--case report and review of literature].

    PubMed

    Gałczyński, Krzysztof; Marciniak, Beata; Kudlicki, Janusz; Kimber-Trojnar, Zaneta; Leszczyńska-Gorzelak, Bozena; Oleszczukz, Jan

    2013-10-01

    The incidence of cardiac arrhythmias is estimated et 1.2 per 1000 pregnancies, usually in the third trimester and 50% of them are asymptomatic. They may appear for the first time in pregnancy or have a recurring character An important risk factor related to their appearance is the presence of structural heart disease, which complicates < 1% of pregnancies. Generally the symptoms are mild and the treatment is not necessary but in some cases pharmacotherapy is necessary Pharmacotherapy must be a compromise between the potentially adverse effects of drugs on the fetus and the beneficial effects on the cardiovascular system of the mother. Due to the development of cardiac surgery many women with heart defects reach reproductive age and become pregnant. Therefore this problem will be faced more and more often in clinical practice. In addition to pharmacological methods some cardiac arrhythmias may require urgent, life-saving procedures. External electrical cardioversion is associated with the application of certain amount of energy via two electrodes placed on the thorax. It is used to treat hemodynamically unstable supraventricular tachycardias, including atrial fibrillation and atrial flutter Also in hemodynamically stable patients in whom drug therapy was ineffective elective electrical cardioversion can be use to convert cardiac arrhythmia to sinus rhythm. We present a case of a 33 years old patient with congenital heart disease surgically corrected in childhood who had first incident of atrial flutter in pregnancy. Arrhytmia occured in 26th week of gestation. The patient was hemodynamically stable and did not approve electrical cardioversion as a method of treatment therefore pharmacotherapy was started. Heart rate was controled with metoprolol and digoxin, warfarin was used to anticoagulation. Calcium and potassium were also given. Described therapy did not convert atrial flutter to sinus rhythm therefore in 33rd week of gestation after patient's approval

  17. Pathogenesis of Lethal Cardiac Arrhythmias in Mecp2 Mutant Mice: Implication for Therapy in Rett Syndrome

    PubMed Central

    McCauley, Mark D.; Wang, Tiannan; Mike, Elise; Herrera, Jose; Beavers, David L.; Huang, Teng-Wei; Ward, Christopher S.; Skinner, Steven; Percy, Alan K.; Glaze, Daniel G.; Wehrens, Xander H. T.; Neul, Jeffrey L.

    2013-01-01

    Rett Syndrome is a neurodevelopmental disorder typically caused by mutations in Methyl-CpG-Binding Protein 2 (MECP2) in which 26% of deaths are sudden and of unknown cause. To explore the hypothesis that these deaths may be due to cardiac dysfunction, we characterized the electrocardiograms (ECGs) in 379 people with Rett syndrome and found that 18.5% show prolongation of the corrected QT interval (QTc), indicating a repolarization abnormality that can predispose to the development of an unstable fatal cardiac rhythm. Male mice lacking MeCP2 function, Mecp2Null/Y, also have prolonged QTc and show increased susceptibility to induced ventricular tachycardia. Female heterozygous null mice, Mecp2Null/+, show an age-dependent prolongation of QTc associated with ventricular tachycardia and cardiac-related death. Genetic deletion of MeCP2 function in only the nervous system was sufficient to cause long QTc and ventricular tachycardia, implicating neuronally-mediated changes to cardiac electrical conduction as a potential cause of ventricular tachycardia in Rett syndrome. The standard therapy for prolonged QTc in Rett syndrome, β-adrenergic receptor blockers, did not prevent ventricular tachycardia in Mecp2Null/Y mice. To determine whether an alternative therapy would be more appropriate, we characterized cardiomyocytes from Mecp2Null/Y mice and found increased persistent sodium current, which was normalized when cells were treated with the sodium channel-blocking anti-seizure drug phenytoin. Treatment with phenytoin reduced both QTc and sustained ventricular tachycardia in Mecp2Null/Y mice. These results demonstrate that cardiac abnormalities in Rett syndrome are secondary to abnormal nervous system control, which leads to increased persistent sodium current. Our findings suggest that treatment in people with Rett syndrome would be more effective if it targeted the increased persistent sodium current in order to prevent lethal cardiac arrhythmias. PMID:22174313

  18. Pathogenesis of lethal cardiac arrhythmias in Mecp2 mutant mice: implication for therapy in Rett syndrome.

    PubMed

    McCauley, Mark D; Wang, Tiannan; Mike, Elise; Herrera, Jose; Beavers, David L; Huang, Teng-Wei; Ward, Christopher S; Skinner, Steven; Percy, Alan K; Glaze, Daniel G; Wehrens, Xander H T; Neul, Jeffrey L

    2011-12-14

    Rett syndrome is a neurodevelopmental disorder typically caused by mutations in methyl-CpG-binding protein 2 (MECP2) in which 26% of deaths are sudden and of unknown cause. To explore the hypothesis that these deaths may be due to cardiac dysfunction, we characterized the electrocardiograms in 379 people with Rett syndrome and found that 18.5% show prolongation of the corrected QT interval (QTc), an indication of a repolarization abnormality that can predispose to the development of an unstable fatal cardiac rhythm. Male mice lacking MeCP2 function, Mecp2(Null/Y), also have prolonged QTc and show increased susceptibility to induced ventricular tachycardia. Female heterozygous null mice, Mecp2(Null/+), show an age-dependent prolongation of QTc associated with ventricular tachycardia and cardiac-related death. Genetic deletion of MeCP2 function in only the nervous system was sufficient to cause long QTc and ventricular tachycardia, implicating neuronally mediated changes to cardiac electrical conduction as a potential cause of ventricular tachycardia in Rett syndrome. The standard therapy for prolonged QTc in Rett syndrome, β-adrenergic receptor blockers, did not prevent ventricular tachycardia in Mecp2(Null/Y) mice. To determine whether an alternative therapy would be more appropriate, we characterized cardiomyocytes from Mecp2(Null/Y) mice and found increased persistent sodium current, which was normalized when cells were treated with the sodium channel-blocking anti-seizure drug phenytoin. Treatment with phenytoin reduced both QTc and sustained ventricular tachycardia in Mecp2(Null/Y) mice. These results demonstrate that cardiac abnormalities in Rett syndrome are secondary to abnormal nervous system control, which leads to increased persistent sodium current. Our findings suggest that treatment in people with Rett syndrome would be more effective if it targeted the increased persistent sodium current to prevent lethal cardiac arrhythmias.

  19. Cardiac sodium channel Nav1.5 mutations and cardiac arrhythmia.

    PubMed

    Song, Weihua; Shou, Weinian

    2012-08-01

    As a major cardiac voltage-gated sodium channel isoform in the heart, the Nav1.5 channel is essential for cardiac action potential initiation and subsequent propagation throughout the heart. Mutations of Nav1.5 have been linked to a variety of cardiac diseases such as long QT syndrome (LQTs), Brugada syndrome, cardiac conduction defect, atrial fibrillation, and dilated cardiomyopathy. The mutagenesis approach and heterologous expression systems are most frequently used to study the function of this channel. This review focuses primarily on recent findings of Nav1.5 mutations associated with type 3 long QT syndrome (LQT3) in particular. Understanding the functional changes of the Nav1.5 mutation may offer critical insight into the mechanism of long QT3 syndrome. In addition, this review provides the updated information on the current progress of using various experimental model systems to study primarily the long QT3 syndrome.

  20. Aging is a primary risk factor for cardiac arrhythmias: disruption of intracellular Ca2+ regulation as a key suspect.

    PubMed

    Hatch, Fiona; Lancaster, Matthew K; Jones, Sandra A

    2011-08-01

    Aging is an inevitable time-dependent progression associated with a functional decline of the cardiovascular system even in 'healthy' individuals. Age positively correlates with an increasing risk of cardiac problems including arrhythmias. Not only the prevalence but also the severity of arrhythmias escalates with age. The reasons for this are multifactorial but dysregulation of intracellular calcium within the heart is likely to play a key role in initiating and perpetuating these life-threatening events. We now know that several aspects of cardiac calcium regulation significantly change with advancing age - changes that could produce electrical instability. Further development of knowledge of the mechanisms underlying these changes will allow us to reduce what currently is an inevitable increase in the incidence of arrhythmias in the elderly.

  1. Primary Cardiac Sarcoidosis with Syncope and Refractory Atrial Arrhythmia: A Case Report and Review of the Literature

    PubMed Central

    Thangam, Manoj; Nathan, Sriram; Kar, Biswajit; Petrovic, Marija; Patel, Manish; Loyalka, Pranav; Buja, L. Maximilian

    2016-01-01

    We discuss the case of a 38-year-old black man who presented at our hospital with his first episode of syncope, recently developed atrial arrhythmias refractory to pharmacologic therapy, and a left atrial thrombus. He was diagnosed with primary cardiac sarcoidosis characterized by predominant involvement of the epicardium that caused atrial fibrillation and atrial flutter. Histologic analysis of his epicardial lesions yielded a diagnosis of sarcoidosis. This patient's atrial arrhythmia was successfully treated with a hybrid operation that involved resection of his atrial appendage, an Epicor maze procedure, and radiofrequency ablation during a catheter-based electrophysiologic study. The cardiac sarcoidosis was successfully managed with corticosteroid therapy. Our case report shows that sarcoidosis can initially manifest itself as syncope with new-onset atrial arrhythmia. Sarcoidosis is important in the differential diagnosis because of its progressive nature and its potential for treatment with pharmacologic, surgical, and catheter-based interventions. PMID:27303240

  2. Long-term cardiac remodeling and arrhythmias in nonelite marathon runners.

    PubMed

    Wilhelm, Matthias; Roten, Laurent; Tanner, Hildegard; Schmid, Jean-Paul; Wilhelm, Ilca; Saner, Hugo

    2012-07-01

    Long-term endurance sports are associated with atrial remodeling and atrial arrhythmias. More importantly, high-level endurance training may promote right ventricular (RV) dysfunction and complex ventricular arrhythmias. We investigated the long-term consequences of marathon running on cardiac remodeling as a potential substrate for arrhythmias with a focus on the right heart. We invited runners of the 2010 Grand Prix of Bern, a 10-mile race. Of 873 marathon and nonmarathon runners who applied, 122 (61 women) entered the final analysis. Subjects were stratified according to former marathon participations: control group (nonmarathon runners, n = 34), group 1 (1 marathon to 5 marathons, mean 2.7, n = 46), and group 2 (≥6 marathons, mean 12.8, n = 42). Mean age was 42 ± 7 years. Results were adjusted for gender, age, and lifetime training hours. Right and left atrial sizes increased with marathon participations. In group 2, right and left atrial enlargements were present in 60% and 74% of athletes, respectively. RV and left ventricular (LV) dimensions showed no differences among groups, and RV or LV dilatation was present in only 2.4% or 4.3% of marathon runners, respectively. In multiple linear regression analysis, marathon participation was an independent predictor of right and left atrial sizes but had no effect on RV and LV dimensions and function. Atrial and ventricular ectopic complexes during 24-hour Holter monitoring were low and equally distributed among groups. In conclusion, in nonelite athletes, marathon running was not associated with RV enlargement, dysfunction, or ventricular ectopy. Marathon running promoted biatrial remodeling.

  3. Long-Term Continuous Ambulatory ECG Monitors and External Cardiac Loop Recorders for Cardiac Arrhythmia: A Health Technology Assessment

    PubMed Central

    Kabali, Conrad; Xie, Xuanqian; Higgins, Caroline

    2017-01-01

    Background Ambulatory electrocardiography (ECG) monitors are often used to detect cardiac arrhythmia. For patients with symptoms, an external cardiac loop recorder will often be recommended. The improved recording capacity of newer Holter monitors and similar devices, collectively known as longterm continuous ambulatory ECG monitors, suggests that they will perform just as well as, or better than, external loop recorders. This health technology assessment aimed to evaluate the effectiveness, cost-effectiveness, and budget impact of longterm continuous ECG monitors compared with external loop recorders in detecting symptoms of cardiac arrhythmia. Methods Based on our systematic search for studies published up to January 15, 2016, we did not identify any studies directly comparing the clinical effectiveness of longterm continuous ECG monitors and external loop recorders. Therefore, we conducted an indirect comparison, using a 24-hour Holter monitor as a common comparator. We used a meta-regression model to control for bias due to variation in device-wearing time and baseline syncope rate across studies. We conducted a similar systematic search for cost-utility and cost-effectiveness studies comparing the two types of devices; none were found. Finally, we used historical claims data (2006–2014) to estimate the future 5-year budget impact in Ontario, Canada, of continued public funding for both types of longterm ambulatory ECG monitors. Results Our clinical literature search yielded 7,815 non-duplicate citations, of which 12 cohort studies were eligible for indirect comparison. Seven studies assessed the effectiveness of longterm continuous monitors and five assessed external loop recorders. Both types of devices were more effective than a 24-hour Holter monitor, and we found no substantial difference between them in their ability to detect symptoms (risk difference 0.01; 95% confidence interval −0.18, 0.20). Using GRADE for network meta-analysis, we evaluated the

  4. Cell-cell junction remodeling in the heart: possible role in cardiac conduction system function and arrhythmias?

    PubMed

    Mezzano, Valeria; Sheikh, Farah

    2012-02-27

    Anchoring cell-cell junctions (desmosomes, fascia adherens) play crucial roles in maintaining mechanical integrity of cardiac muscle cells and tissue. Genetic mutations and/or loss of critical components in these macromolecular structures are increasingly being associated with arrhythmogenic cardiomyopathies; however, their specific roles have been primarily attributed to effects within the working (ventricular) cardiac muscle. Growing evidence also points to a key role for anchoring cell-cell junction components in cardiac muscle cells of the cardiac conduction system. This is not only evidenced by the molecular and ultra-structural presence of anchoring cell junctions in specific compartments/structures of the cardiac conduction system (sinoatrial node, atrioventricular node, His-Purkinje system), but also because conduction system-related arrhythmias can be found in humans and mouse models of cardiomyopathies harboring defects and/or mutations in key anchoring cell-cell junction proteins. These studies emphasize the clinical need to understand the molecular and cellular role(s) for anchoring cell-cell junctions in cardiac conduction system function and arrhythmias. This review will focus on (i) experimental findings that underline an important role for anchoring cell-cell junctions in the cardiac conduction system, (ii) insights regarding involvement of these structures in age-related cardiac remodeling of the conduction system, (iii) summarizing available genetic mouse models that can target cardiac conduction system structures and (iv) implications of these findings on future therapies for arrhythmogenic heart diseases.

  5. Progesterone Protects Against BPA-induced Arrhythmias in Female Rat Cardiac Myocytes via Rapid Signaling.

    PubMed

    Ma, Jianyong; Hong, Kui; Wang, Hong-Sheng

    2017-01-25

    Bisphenol A (BPA) is an estrogenic endocrine disrupting chemical (EDC) that has a range of potential adverse health effects. Previously we showed that acute exposure to BPA promoted arrhythmias in female rat hearts through estrogen receptor rapid signaling. Progesterone (P4) and estrogen have antagonistic or complementary actions in a number of tissues and systems. In the current study, we examined the influence, and possible protective effect, of P4 on the rapid cardiac actions of BPA in female rat cardiac myocytes. Preincubation with physiological concentration (1 nM) of P4 abolished BPA-induced triggered activities in female cardiac myocytes. Further, P4 abrogated BPA-induced alterations in Ca2+ handling including elevated sarcoplasmic reticulum Ca2+ leak and Ca2+ load. Key to the inhibitory effect of P4 is its blockade of BPA-induced increase in the phosphorylation of phospholamban. At myocyte and protein levels, these inhibitory actions of P4 were blocked by pretreatment with the nuclear P4 receptor (nPR) antagonist RU486. Analysis using membrane impermeable BSA-conjugated P4 suggested that the actions of P4 were mediated by membrane-initiated signaling. The inhibitory G (Gi) protein and phophoinositide-3 kinase (PI3K), but not tyrosine protein kinase activation, were involved in the observed effects of P4. In conclusion, P4 exerts an acute protective effect against BPA-induced arrhythmogenesis in female cardiac myocytes, through nPR and the Gi/PI3K signaling pathway. Our findings highlight the importance of considering the impact of EDCs in the context of native hormonals, and may provide potential therapeutic strategies for the protection against the cardiac toxicities associated with BPA exposure.

  6. Cardiac arrhythmia and death of teenager linked to rare genetic disorder diagnosed at autopsy.

    PubMed

    Quick, Jennifer Sue; Dobersen, Michael

    2014-06-01

    A 17-year-old male adolescent sustained cardiac arrest after participating in a wrestling match, where he was thrown down. He had no pulse, and cardiopulmonary resuscitation was immediately initiated along with application of an automatic external defibrillator. Upon arrival of emergency medical services, an electrocardiogram showed the patient to be in ventricular tachycardia, torsades, and ventricular fibrillation. The patient was ultimately transported to the hospital and, with ACLS protocol being performed, was resuscitated to a junctional rhythm with bradycardia and borderline prolonged QT. His hospital stay was characterized by refractory cardiac failure, and 2 days after the incident, a decision was made to remove him from life support. At autopsy, there were no external or internal injuries that could be considered a contributing cause of death. On external examination, observations were made about the decedent's facial features including his nose, eyes, ears, fingers, and toes. A careful review of the decedent's medical history was initiated to reveal birth defects including syndactyly of the third and fourth digit of the upper extremity as well as complete lack of dental enamel. A tentative diagnosis of oculodentodigital dysplasia was made and confirmed by genetic testing of heart muscle taken from the decedent. This case report examines the rare association of oculodentodigital dysplasia with cardiac arrhythmia as well as places emphasis on the features of the disorder that can aid in its diagnosis.

  7. Low dialysate potassium concentration: an overrated risk factor for cardiac arrhythmia?

    PubMed

    Abuelo, J Gary

    2015-01-01

    Serum potassium concentrations rise with dietary potassium intake between dialysis sessions and are often at hyperkalemic levels by the next session. Conversely, potassium concentrations fall during each hemodialysis, and sometimes reach hypokalemic levels by the end. Low potassium dialysate, which rapidly decreases serum potassium and often brings it to hypokalemic levels, is almost universally considered a risk factor for life-threatening arrhythmias. While there is little doubt about the threat of lethal arrhythmias due to hyperkalemia, convincing evidence for the danger of low potassium dialysate and rapid or excess potassium removal has not been forthcoming. The original report of more frequent ventricular ectopy in early dialysis that was improved by reducing potassium removal has received very little confirmation from subsequent studies. Furthermore, the occurrence of ventricular ectopy during dialysis does not appear to predict mortality. Studies relating sudden deaths to low potassium dialysate are countered by studies with more thorough adjustment for markers of poor health. Dialysate potassium concentrations affect the excursions of serum potassium levels above or below the normal range, and have the potential to influence dialysis safety. Controlled studies of different dialysate potassium concentration and their effect on mortality and cardiac arrests have not been done. Until these results become available, I propose interim guidelines for the setting of dialysate potassium levels that may better balance risks and benefits.

  8. SK4 K(+) channels are therapeutic targets for the treatment of cardiac arrhythmias.

    PubMed

    Haron-Khun, Shiraz; Weisbrod, David; Bueno, Hanna; Yadin, Dor; Behar, Joachim; Peretz, Asher; Binah, Ofer; Hochhauser, Edith; Eldar, Michael; Yaniv, Yael; Arad, Michael; Attali, Bernard

    2017-02-20

    Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a stress-provoked ventricular arrhythmia, which also manifests sinoatrial node (SAN) dysfunction. We recently showed that SK4 calcium-activated potassium channels are important for automaticity of cardiomyocytes derived from human embryonic stem cells. Here SK4 channels were identified in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) from healthy and CPVT2 patients bearing a mutation in calsequestrin 2 (CASQ2-D307H) and in SAN cells from WT and CASQ2-D307H knock-in (KI) mice. TRAM-34, a selective blocker of SK4 channels, prominently reduced delayed afterdepolarizations and arrhythmic Ca(2+) transients observed following application of the β-adrenergic agonist isoproterenol in CPVT2-derived hiPSC-CMs and in SAN cells from KI mice. Strikingly, in vivo ECG recording showed that intraperitoneal injection of the SK4 channel blockers, TRAM-34 or clotrimazole, greatly reduced the arrhythmic features of CASQ2-D307H KI and CASQ2 knockout mice at rest and following exercise. This work demonstrates the critical role of SK4 Ca(2+)-activated K(+) channels in adult pacemaker function, making them promising therapeutic targets for the treatment of cardiac ventricular arrhythmias such as CPVT.

  9. Automatic cardiac arrhythmia detection and classification using vectorcardiograms and complex networks.

    PubMed

    Queiroz, Vinícius; Luz, Eduardo; Moreira, Gladston; Guarda, Álvaro; Menotti, David

    2015-01-01

    This paper intends to bring new insights in the methods for extracting features for cardiac arrhythmia detection and classification systems. We explore the possibility for utilizing vectorcardiograms (VCG) along with electrocardiograms (ECG) to get relevant informations from the heartbeats on the MIT-BIH database. For this purpose, we apply complex networks to extract features from the VCG. We follow the ANSI/AAMI EC57:1998 standard, for classifying the beats into 5 classes (N, V, S, F and Q), and de Chazal's scheme for dataset division into training and test set, with 22 folds validation setup for each set. We used the Support Vector Machinhe (SVM) classifier and the best result we chose had a global accuracy of 84.1%, while still obtaining relatively high Sensitivities and Positive Predictive Value and low False Positive Rates, when compared to other papers that follows the same evaluation methodology that we do.

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

    PubMed Central

    Jagu, Benoît; Charpentier, Flavien; Toumaniantz, Gilles

    2013-01-01

    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 behavior 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 a-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. The aim of this review is to inventory, through the description of few representative examples, the role of these different biogenic mechanisms in arrhythmogenesis, HF and SCD in order to help the researcher to identify all the processes that could lead to arrhythmias. Identification of novel targets for drug intervention should result from further understanding of these fundamental mechanisms. PMID:24065925

  11. Calcium Transients Closely Reflect Prolonged Action Potentials in iPSC Models of Inherited Cardiac Arrhythmia

    PubMed Central

    Spencer, C. Ian; Baba, Shiro; Nakamura, Kenta; Hua, Ethan A.; Sears, Marie A.F.; Fu, Chi-cheng; Zhang, Jianhua; Balijepalli, Sadguna; Tomoda, Kiichiro; Hayashi, Yohei; Lizarraga, Paweena; Wojciak, Julianne; Scheinman, Melvin M.; Aalto-Setälä, Katriina; Makielski, Jonathan C.; January, Craig T.; Healy, Kevin E.; Kamp, Timothy J.; Yamanaka, Shinya; Conklin, Bruce R.

    2014-01-01

    Summary Long-QT syndrome mutations can cause syncope and sudden death by prolonging the cardiac action potential (AP). Ion channels affected by mutations are various, and the influences of cellular calcium cycling on LQTS cardiac events are unknown. To better understand LQTS arrhythmias, we performed current-clamp and intracellular calcium ([Ca2+]i) measurements on cardiomyocytes differentiated from patient-derived induced pluripotent stem cells (iPS-CM). In myocytes carrying an LQT2 mutation (HERG-A422T), APs and [Ca2+]i transients were prolonged in parallel. APs were abbreviated by nifedipine exposure and further lengthened upon releasing intracellularly stored Ca2+. Validating this model, control iPS-CM treated with HERG-blocking drugs recapitulated the LQT2 phenotype. In LQT3 iPS-CM, expressing NaV1.5-N406K, APs and [Ca2+]i transients were markedly prolonged. AP prolongation was sensitive to tetrodotoxin and to inhibiting Na+-Ca2+ exchange. These results suggest that LQTS mutations act partly on cytosolic Ca2+ cycling, potentially providing a basis for functionally targeted interventions regardless of the specific mutation site. PMID:25254341

  12. Disclosing Genetic Information to Family Members About Inherited Cardiac Arrhythmias: An Obligation or a Choice?

    PubMed

    Vavolizza, Rick D; Kalia, Isha; Erskine Aaron, Kathleen; Silverstein, Louise B; Barlevy, Dorit; Wasserman, David; Walsh, Christine; Marion, Robert W; Dolan, Siobhan M

    2015-08-01

    Inherited cardiac arrhythmias such as long QT syndrome and Brugada syndrome, present clinical as well as ethical, legal, and social challenges. Many individuals who carry a deleterious mutation are largely asymptomatic and therefore may not be diagnosed until after the occurrence of a personal or family member's cardiac event. The familial nature of inherited genetic information raises numerous ethical, legal, and social issues regarding the sharing of genetic information, particularly when an individual found to carry a deleterious mutation refuses to disclose his or her results to at-risk family members who could benefit from life-saving treatments. This qualitative study sought to understand the experiences with genetic testing for individuals (n = 50) with a personal or family history of cardiac events or sudden death. Unstructured in-person focus groups or interviews were conducted for each participant in the study. The recordings of these interviews were transcribed verbatim and subsequently analyzed and coded. Participants' comments regarding sharing of genetic information centered around four main themes: (1) motivation to disclose; (2) extent of disclosure; (3) effect of disclosure on family dynamics; and (4) reasons for not sharing genetic information. The majority of individuals believed that affected individuals are obligated to disclose genetic information to family members. In the era of personalized medicine, the disclosure of genetic information provides individuals the opportunities to learn about the genetics, disease characteristics, and treatment options in order to reduce morbidity and mortality in themselves and their family members. Further research is necessary to identify and explore the barriers to sharing genetic information with at-risk family members.

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

    PubMed Central

    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

    2016-01-01

    Background— 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. Methods and Results— 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. Conclusions— 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. PMID:27390211

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

    EPA Science Inventory

    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...

  15. Development of a patch type embedded cardiac function monitoring system using dual microprocessor for arrhythmia detection in heart disease patient.

    PubMed

    Jang, Yongwon; Noh, Hyung Wook; Lee, I B; Jung, Ji-Wook; Song, Yoonseon; Lee, Sooyeul; Kim, Seunghwan

    2012-01-01

    A patch type embedded cardiac function monitoring system was developed to detect arrhythmias such as PVC (Premature Ventricular Contraction), pause, ventricular fibrillation, and tachy/bradycardia. The overall system is composed of a main module including a dual processor and a Bluetooth telecommunication module. The dual microprocessor strategy minimizes power consumption and size, and guarantees the resources of embedded software programs. The developed software was verified with standard DB, and showed good performance.

  16. Investigation of mechanisms and non-pharmacological therapy of cardiac arrhythmias

    NASA Astrophysics Data System (ADS)

    Vago, Hajnalka

    apply effectively biatrial pacemaker and biatrial cardioverter defibrillator for the prevention of paroxysmal atrial fibrillation. In the majority of patients frequency of paroxysmal atrial fibrillation decreased significantly due to biatrial stimulation or combined pharmacological and resynchronisation therapy. Parasymphathetic cardiac neurostimulation is a promising new non-pharmacological treatment option in certain types of arrhythmias. In our clinical study we were able to stimulate cardiac parasympathetic nerves innervating atrioventricular node achieving ventricular rate control during atrial tachyarrhythmias with chronically implanted coronary sinus lead. In our study biventricular pacemakers and cardioverter defibrillators were applied successfully in the treatment of drug refractory congestive heart failure combined with inter- and/or intraventricular conduction disturbances. AV sequential left sided chronic pacing using a single lead located in the coronary sinus has not been previously reported. Left sided DDD pacing was effective chronically in the improvement of the functional stage of patient suffering from congestive heart disease combined with left bundle branch block and binodal disease. Parallel with the investigation of pathomechanism of life-threatening ventricular tachyarrhythmias and the most common, clinically relevant atrial fibrillation due to recent technical development, we were able to support nonpharmacological therapeutic modalities, gaining popularity in clinical management, with novel observations.

  17. Fatal cardiac arrhythmia after repeated exposure to 1,1-difluoroethane (DFE).

    PubMed

    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.

  18. The role of late I Na in development of cardiac arrhythmias.

    PubMed

    Antzelevitch, Charles; Nesterenko, Vladislav; Shryock, John C; Rajamani, Sridharan; Song, Yejia; Belardinelli, Luiz

    2014-01-01

    Late I Na is an integral part of the sodium current, which persists long after the fast-inactivating component. The magnitude of the late I Na is relatively small in all species and in all types of cardiomyocytes as compared with the amplitude of the fast sodium current, but it contributes significantly to the shape and duration of the action potential. This late component had been shown to increase in several acquired or congenital conditions, including hypoxia, oxidative stress, and heart failure, or due to mutations in SCN5A, which encodes the α-subunit of the sodium channel, as well as in channel-interacting proteins, including multiple β subunits and anchoring proteins. Patients with enhanced late I Na exhibit the type-3 long QT syndrome (LQT3) characterized by high propensity for the life-threatening ventricular arrhythmias, such as Torsade de Pointes (TdP), as well as for atrial fibrillation. There are several distinct mechanisms of arrhythmogenesis due to abnormal late I Na, including abnormal automaticity, early and delayed after depolarization-induced triggered activity, and dramatic increase of ventricular dispersion of repolarization. Many local anesthetic and antiarrhythmic agents have a higher potency to block late I Na as compared with fast I Na. Several novel compounds, including ranolazine, GS-458967, and F15845, appear to be the most selective inhibitors of cardiac late I Na reported to date. Selective inhibition of late I Na is expected to be an effective strategy for correcting these acquired and congenital channelopathies.

  19. Characterization of 2 genetic variants of Na(v) 1.5-arginine 689 found in patients with cardiac arrhythmias.

    PubMed

    Sottas, Valentin; Rougier, Jean-Sébastien; Jousset, Florian; Kucera, Jan P; Shestak, Anna; Makarov, Leonid M; Zaklyazminskaya, Elena V; Abriel, Hugues

    2013-09-01

    Hundreds of genetic variants in SCN5A, the gene coding for the pore-forming subunit of the cardiac sodium channel, Na(v) 1.5, have been described in patients with cardiac channelopathies as well as in individuals from control cohorts. The aim of this study was to characterize the biophysical properties of 2 naturally occurring Na(v) 1.5 variants, p.R689H and p.R689C, found in patients with cardiac arrhythmias and in control individuals. In addition, this study was motivated by the finding of the variant p.R689H in a family with sudden cardiac death (SCD) in children. When expressed in HEK293 cells, most of the sodium current (I(Na)) biophysical properties of both variants were indistinguishable from the wild-type (WT) channels. In both cases, however, an ∼2-fold increase of the tetrodotoxin-sensitive late I(Na) was observed. Action potential simulations and reconstruction of pseudo-ECGs demonstrated that such a subtle increase in the late I(Na) may prolong the QT interval in a nonlinear fashion. In conclusion, despite the fact that the causality link between p.R689H and the phenotype of the studied family cannot be demonstrated, this study supports the notion that subtle alterations of Na(v) 1.5 variants may increase the risk for cardiac arrhythmias.

  20. Sarcomere mechanics in uniform and nonuniform cardiac muscle: a link between pump function and arrhythmias.

    PubMed

    Ter Keurs, Henk E D J; Shinozaki, Tsuyoshi; Zhang, Ying Ming; Wakayama, Yuji; Sugai, Yoshinao; Kagaya, Yutaka; Miura, Masahito; Boyden, Penelope A; Stuyvers, Bruno D M; Landesberg, Amir

    2008-03-01

    Ca2+ waves and reversibly induced arrhythmias. We hypothesize that rapid force loss by the sarcomeres in the border zone during relaxation causes Ca2+ release from Tn-C and initiates Ca2+ waves propagated by the sarcoplasmic reticulum (SR). Modeling of the response of the cardiac twitch to rapid force changes using the feedback concept uniquely predicts the occurrence of [Ca2+]i transients as a result of accelerated Ca2+ dissociation from Tn-C. These results are consistent with the hypothesis that a force feedback to Ca2+ binding by Tn-C is responsible for Starling's law and the ESPVR in the uniform myocardium and leads to a surge of Ca2+ released by the myofilaments during relaxation in the nonuniform myocardium, which initiates arrhythmogenic propagating Ca2+ release by the SR.

  1. Treatment of cardiac arrhythmias in a mouse model of Rett syndrome with Na+-channel-blocking antiepileptic drugs.

    PubMed

    Herrera, José A; Ward, Christopher S; Pitcher, Meagan R; Percy, Alan K; Skinner, Steven; Kaufmann, Walter E; Glaze, Daniel G; Wehrens, Xander H T; Neul, Jeffrey L

    2015-04-01

    One quarter of deaths associated with Rett syndrome (RTT), an X-linked neurodevelopmental disorder, are sudden and unexpected. RTT is associated with prolonged QTc interval (LQT), and LQT-associated cardiac arrhythmias are a potential cause of unexpected death. The standard of care for LQT in RTT is treatment with β-adrenergic antagonists; however, recent work indicates that acute treatment of mice with RTT with a β-antagonist, propranolol, does not prevent lethal arrhythmias. In contrast, acute treatment with the Na(+) channel blocker phenytoin prevented arrhythmias. Chronic dosing of propranolol may be required for efficacy; therefore, we tested the efficacy of chronic treatment with either propranolol or phenytoin on RTT mice. Phenytoin completely abolished arrhythmias, whereas propranolol showed no benefit. Surprisingly, phenytoin also normalized weight and activity, but worsened breathing patterns. To explore the role of Na(+) channel blockers on QT in people with RTT, we performed a retrospective analysis of QT status before and after Na(+) channel blocker antiepileptic therapies. Individuals with RTT and LQT significantly improved their QT interval status after being started on Na(+) channel blocker antiepileptic therapies. Thus, Na(+) channel blockers should be considered for the clinical management of LQT in individuals with RTT.

  2. Splicing misregulation of SCN5A contributes to cardiac-conduction delay and heart arrhythmia in myotonic dystrophy

    PubMed Central

    Freyermuth, Fernande; Rau, Frédérique; Kokunai, Yosuke; Linke, Thomas; Sellier, Chantal; Nakamori, Masayuki; Kino, Yoshihiro; Arandel, Ludovic; Jollet, Arnaud; Thibault, Christelle; Philipps, Muriel; Vicaire, Serge; Jost, Bernard; Udd, Bjarne; Day, John W.; Duboc, Denis; Wahbi, Karim; Matsumura, Tsuyoshi; Fujimura, Harutoshi; Mochizuki, Hideki; Deryckere, François; Kimura, Takashi; Nukina, Nobuyuki; Ishiura, Shoichi; Lacroix, Vincent; Campan-Fournier, Amandine; Navratil, Vincent; Chautard, Emilie; Auboeuf, Didier; Horie, Minoru; Imoto, Keiji; Lee, Kuang-Yung; Swanson, Maurice S.; de Munain, Adolfo Lopez; Inada, Shin; Itoh, Hideki; Nakazawa, Kazuo; Ashihara, Takashi; Wang, Eric; Zimmer, Thomas; Furling, Denis; Takahashi, Masanori P.; Charlet-Berguerand, Nicolas

    2016-01-01

    Myotonic dystrophy (DM) is caused by the expression of mutant RNAs containing expanded CUG repeats that sequester muscleblind-like (MBNL) proteins, leading to alternative splicing changes. Cardiac alterations, characterized by conduction delays and arrhythmia, are the second most common cause of death in DM. Using RNA sequencing, here we identify novel splicing alterations in DM heart samples, including a switch from adult exon 6B towards fetal exon 6A in the cardiac sodium channel, SCN5A. We find that MBNL1 regulates alternative splicing of SCN5A mRNA and that the splicing variant of SCN5A produced in DM presents a reduced excitability compared with the control adult isoform. Importantly, reproducing splicing alteration of Scn5a in mice is sufficient to promote heart arrhythmia and cardiac-conduction delay, two predominant features of myotonic dystrophy. In conclusion, misregulation of the alternative splicing of SCN5A may contribute to a subset of the cardiac dysfunctions observed in myotonic dystrophy. PMID:27063795

  3. Splicing misregulation of SCN5A contributes to cardiac-conduction delay and heart arrhythmia in myotonic dystrophy.

    PubMed

    Freyermuth, Fernande; Rau, Frédérique; Kokunai, Yosuke; Linke, Thomas; Sellier, Chantal; Nakamori, Masayuki; Kino, Yoshihiro; Arandel, Ludovic; Jollet, Arnaud; Thibault, Christelle; Philipps, Muriel; Vicaire, Serge; Jost, Bernard; Udd, Bjarne; Day, John W; Duboc, Denis; Wahbi, Karim; Matsumura, Tsuyoshi; Fujimura, Harutoshi; Mochizuki, Hideki; Deryckere, François; Kimura, Takashi; Nukina, Nobuyuki; Ishiura, Shoichi; Lacroix, Vincent; Campan-Fournier, Amandine; Navratil, Vincent; Chautard, Emilie; Auboeuf, Didier; Horie, Minoru; Imoto, Keiji; Lee, Kuang-Yung; Swanson, Maurice S; Lopez de Munain, Adolfo; Inada, Shin; Itoh, Hideki; Nakazawa, Kazuo; Ashihara, Takashi; Wang, Eric; Zimmer, Thomas; Furling, Denis; Takahashi, Masanori P; Charlet-Berguerand, Nicolas

    2016-04-11

    Myotonic dystrophy (DM) is caused by the expression of mutant RNAs containing expanded CUG repeats that sequester muscleblind-like (MBNL) proteins, leading to alternative splicing changes. Cardiac alterations, characterized by conduction delays and arrhythmia, are the second most common cause of death in DM. Using RNA sequencing, here we identify novel splicing alterations in DM heart samples, including a switch from adult exon 6B towards fetal exon 6A in the cardiac sodium channel, SCN5A. We find that MBNL1 regulates alternative splicing of SCN5A mRNA and that the splicing variant of SCN5A produced in DM presents a reduced excitability compared with the control adult isoform. Importantly, reproducing splicing alteration of Scn5a in mice is sufficient to promote heart arrhythmia and cardiac-conduction delay, two predominant features of myotonic dystrophy. In conclusion, misregulation of the alternative splicing of SCN5A may contribute to a subset of the cardiac dysfunctions observed in myotonic dystrophy.

  4. Short-term forecasting of life-threatening cardiac arrhythmias based on symbolic dynamics and finite-time growth rates

    NASA Astrophysics Data System (ADS)

    Wessel, Niels; Ziehmann, Christine; Kurths, Jürgen; Meyerfeldt, Udo; Schirdewan, Alexander; Voss, Andreas

    2000-01-01

    Ventricular tachycardia or fibrillation (VT-VF) as fatal cardiac arrhythmias are the main factors triggering sudden cardiac death. The objective of this study is to find early signs of sustained VT-VF in patients with an implanted cardioverter-defibrillator (ICD). These devices are able to safeguard patients by returning their hearts to a normal rhythm via strong defibrillatory shocks; additionally, they store the 1000 beat-to-beat intervals immediately before the onset of a life-threatening arrhythmia. We study these 1000 beat-to-beat intervals of 17 chronic heart failure ICD patients before the onset of a life-threatening arrhythmia and at a control time, i.e., without a VT-VF event. To characterize these rather short data sets, we calculate heart rate variability parameters from the time and frequency domain, from symbolic dynamics as well as the finite-time growth rates. We find that neither the time nor the frequency domain parameters show significant differences between the VT-VF and the control time series. However, two parameters from symbolic dynamics as well as the finite-time growth rates discriminate significantly both groups. These findings could be of importance in algorithms for next generation ICD's to improve the diagnostics and therapy of VT-VF.

  5. Enrollment in clinical trials: institutional factors affecting enrollment in the cardiac arrhythmia suppression trial (CAST).

    PubMed

    Shea, S; Bigger, J T; Campion, J; Fleiss, J L; Rolnitzky, L M; Schron, E; Gorkin, L; Handshaw, K; Kinney, M R; Branyon, M

    1992-12-01

    Recruitment and Enrollment Assessment in Clinical Trials (REACT), an NHLBI-sponsored substudy of the Cardiac Arrhythmia Suppression Trial (CAST), was conducted to assess factors associated with enrollment in clinical trials. We report on the relationships of institutional factors at CAST sites to patient enrollment. The proportion of CAST-eligible patients enrolling at each CAST site during the REACT study period was defined as the number of subjects enrolled divided by the sum of (1) the number enrolled plus (2) the number of eligibles who refused plus (3) the number of eligibles whose physicians refused to permit CAST personnel to attempt to enroll them. A questionnaire that included 78 questions regarding factors hypothesized to be associated with enrollment was completed between August 1988 and February 1990 by the nurse coordinators at all 112 CAST sites in the United States and Canada. Sixteen items were unanalyzable, and 37 of the remaining 62 were grouped into seven scales. The remaining items were analyzed individually. Enrollment proportions varied widely across the 112 CAST sites (mean 32.7% SD 22.6). Five variables or scales were included in the final multiple regression model (multiple R2 = .39). The most important of these was the proportion of eligible patients at a site cared for by medical staff other than private attending physicians (multiple R2 for this variable alone, .26). This proportion tended to be high in teaching hospitals. Other variables in this model that were associated with higher enrollment proportions included the number of days per week a nurse coordinator was present at the site, the number of nurse coordinator full-time equivalents at the site, fewer other clinical trials for which the nurse coordinator was responsible, and fewer perceived obstacles to enrollment. These findings indicate that enrollment was more successful at hospitals with higher proportions of eligible subjects cared for by fellows, housestaff, and service

  6. ST depression, arrhythmia, vagal dominance, and reduced cardiac micro-RNA in particulate-exposed rats.

    PubMed

    Farraj, Aimen K; Hazari, Mehdi S; Haykal-Coates, Najwa; Lamb, Christina; Winsett, Darrell W; Ge, Yue; Ledbetter, Allen D; Carll, Alex P; Bruno, Maribel; Ghio, Andy; Costa, Daniel L

    2011-02-01

    Recently, investigators demonstrated associations between fine particulate matter (PM)-associated metals and adverse health effects. Residual oil fly ash (ROFA), a waste product of fossil fuel combustion from boilers, is rich in the transition metals Fe, Ni, and V, and when released as a fugitive particle, is an important contributor to ambient fine particulate air pollution. We hypothesized that a single-inhalation exposure to transition metal-rich PM will cause concentration-dependent cardiovascular toxicity in spontaneously hypertensive (SH) rats. Rats implanted with telemeters to monitor heart rate and electrocardiogram were exposed once by nose-only inhalation for 4 hours to 3.5 mg/m(3), 1.0 mg/m(3), or 0.45 mg/m(3) of a synthetic PM (dried salt solution), similar in composition to a well-studied ROFA sample consisting of Fe, Ni, and V. Exposure to the highest concentration of PM decreased T-wave amplitude and area, caused ST depression, reduced heart rate (HR), and increased nonconducted P-wave arrhythmias. These changes were accompanied by increased pulmonary inflammation, lung resistance, and vagal tone, as indicated by changes in markers of HR variability (increased root of the mean of squared differences of adjacent RR intervals [RMSSD], low frequency [LF], high frequency [HF], and decreased LF/HF), and attenuated myocardial micro-RNA (RNA segments that suppress translation by targeting messenger RNA) expression. The low and intermediate concentrations of PM had less effect on the inflammatory, HR variability, and micro-RNA endpoints, but still caused significant reductions in HR. In addition, the intermediate concentration caused ST depression and increased QRS area, whereas the low concentration increased the T-wave parameters. Thus, PM-induced cardiac dysfunction is mediated by multiple mechanisms that may be dependent on PM concentration and myocardial vulnerability (this abstract does not reflect the policy of the United States Environmental

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

    SciTech Connect

    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.

  8. Short-term effects of fine particulate air pollution on emergency room visits for cardiac arrhythmias: a case-crossover study in Taipei.

    PubMed

    Chiu, Hui-Fen; Tsai, Shang-Shyue; Weng, Hsu-Huei; Yang, Chun-Yuh

    2013-01-01

    This study was undertaken to determine whether there was an association between fine particles (PM₂.₅) levels and number of emergency room (ER) visits for cardiac arrhythmias in Taipei, Taiwan. ER visits for cardiac arrhythmias and ambient air pollution data for Taipei were obtained for the period 2006-2010. The relative risk (RR) of ER visits was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. For the single-pollutant model (without adjustment for other pollutants), increased numbers of ER cardiac arrhythmia visits were significantly associated with PM₂.₅ on both warm days (>23°C) and cool days (< 23°C), with an interquartile range rise associated with a 10% (95% CI = -15%) and 4% (95% CI = 0-8%) elevation in number of ER visits for cardiac arrhythmias, respectively. In the two-pollutant models, PM₂.₅ levels remained significant after inclusion of sulfur dioxide (SO₂) or ozone (O₃) on both warm and cool days. This study provides evidence that higher levels of PM₂.₅ increase the risk of number of ER visits for cardiac arrhythmias.

  9. Post-translational modifications of the cardiac Na channel: contribution of CaMKII-dependent phosphorylation to acquired arrhythmias

    PubMed Central

    Herren, Anthony W.; Bers, Donald M.

    2013-01-01

    The voltage-gated Na channel isoform 1.5 (NaV1.5) is the pore forming α-subunit of the voltage-gated cardiac Na channel, which is responsible for the initiation and propagation of cardiac action potentials. Mutations in the SCN5A gene encoding NaV1.5 have been linked to changes in the Na current leading to a variety of arrhythmogenic phenotypes, and alterations in the NaV1.5 expression level, Na current density, and/or gating have been observed in acquired cardiac disorders, including heart failure. The precise mechanisms underlying these abnormalities have not been fully elucidated. However, several recent studies have made it clear that NaV1.5 forms a macromolecular complex with a number of proteins that modulate its expression levels, localization, and gating and is the target of extensive post-translational modifications, which may also influence all these properties. We review here the molecular aspects of cardiac Na channel regulation and their functional consequences. In particular, we focus on the molecular and functional aspects of Na channel phosphorylation by the Ca/calmodulin-dependent protein kinase II, which is hyperactive in heart failure and has been causally linked to cardiac arrhythmia. Understanding the mechanisms of altered NaV1.5 expression and function is crucial for gaining insight into arrhythmogenesis and developing novel therapeutic strategies. PMID:23771687

  10. Detection of atrial arrhythmia for cardiac rhythm management by implantable devices.

    PubMed

    Morris, M M; KenKnight, B H; Lang, D J

    2000-01-01

    Implantable atrial defibrillators (IAD) should provide pacing therapy whenever appropriate (ie, typical atrial flutter) to minimize shock-related patient discomfort. Additionally, IADs should provide diagnostics regarding atrial arrhythmia type and frequency of occurrence to enable improved physician management of atrial arrhythmia. To achieve this, IADs should accurately classify atrial arrhythmia such as atrial fibrillation (AF) and atrial flutter (AFL) This article evaluates the performance of an algorithm, atrial rhythm classification (ARC), designed to classify AF and AFL. The ARC algorithm uses maximum rate, standard deviation, and range of the 12 most recent atrial cycle lengths to plot a point in a three-dimensional space. A decision boundary divides the space into 2 regions--faster/unstable atrial cycle lengths (AF) or slower/stable cycle lengths (AFL). Classifications are made on a sliding window of 12 consecutive cycles until the end of the episode is reached. In this way, continuous episode feedback is provided that can be used to help guide device therapy, measure arrhythmia type and frequency of occurrence. Bipolar (1-cm) electrogram episodes of AF (n = 16) and AFL (n = 7) were acquired from 20 patients and retrospectively analyzed using the ARC algorithm. The sensitivity and specificity in this study was 0.993 and 0.982, respectively. The ARC algorithm would have appropriately guided atrial therapy and minimized discomfort associated with defibrillation shocks in this small patient data set warranting further studies. The ARC algorithm may also be beneficial as a diagnostic tool to assist physician management of atrial arrhythmia.

  11. Novel ECG-Synchronized Pulsatile ECLS System With Various Heart Rates and Cardiac Arrhythmias: An In Vitro Study.

    PubMed

    Wang, Shigang; Spencer, Shannon B; Kunselman, Allen R; Ündar, Akif

    2017-01-01

    The objective of this study is to evaluate electrocardiography (ECG)-synchronized pulsatile flow under varying heart rates and different atrial and ventricular arrhythmias in a simulated extracorporeal life support (ECLS) system. The ECLS circuit consisted of an i-cor diagonal pump and console, an iLA membrane ventilator, and an 18 Fr arterial cannula. The circuit was primed with lactated Ringer's solution and packed red blood cells (hematocrit 35%). An ECG simulator was used to trigger pulsatile flow and to generate selected cardiac rhythms. All trials were conducted at a flow rate of 2.5 L/min at room temperature for normal sinus rhythm at 45-180 bpm under non-pulsatile and pulsatile modes. Various atrial and ventricular arrhythmias were also tested. Real-time pressure and flow data were recorded using a custom-based data acquisition system. The energy equivalent pressure (EEP) generated by pulsatile flow was always higher than the mean pressure. No surplus hemodynamic energy (SHE) was recorded under non-pulsatile mode. Under pulsatile mode, SHE levels increased with increasing heart rates (45-120 bpm). SHE levels under a 1:2 assist ratio were higher than the 1:1 and 1:3 assist ratios with a heart rate of 180 bpm. A similar trend was recorded for total hemodynamic energy levels. There was no statistical difference between the two perfusion modes with regards to pressure drops across the ECLS circuit. The main resistance and energy loss came from the arterial cannula. The i-cor console successfully tracked electrocardiographic signals of 12 atrial and ventricular arrhythmias. Our results demonstrated that the i-cor pulsatile ECLS system can be synchronized with a normal heart rate or with various atrial/ventricular arrhythmias. Further in vivo studies are warranted to confirm our findings.

  12. Cardiac arrhythmia is the primary response of embryonic Pacific herring (Clupea pallasi) exposed to crude oil during weathering.

    PubMed

    Incardona, John P; Carls, Mark G; Day, Heather L; Sloan, Catherine A; Bolton, Jennie L; Collier, Tracy K; Scholz, Nathaniel L

    2009-01-01

    Teleost embryos develop a syndrome characterized by edema when exposed to water that weathers substrates contaminated with crude oil. Previous studies using zebrafish demonstrated that crude oil exposure causes cardiogenic edema, and that the most abundant polycyclic aromatic hydrocarbons (PAHs) in weathered crude oils (tricyclic fluorenes, dibenzothiophenes, and phenanthrenes) are cardiotoxic, causing arrhythmia through a pathway that does not require activation of the aryl hydrocarbon receptor (AHR). We demonstrate here for Pacific herring, a species impacted by the Exxon Valdez oil spill, that the developing heart is the primary target of crude oil exposure. Herring embryos exposed to the effluent of oiled gravel columns developed dose-dependent edema and irregular cardiac arrhythmia soon afterthe heartbeat was established. At a dose that produced cardiac dysfunction in 100% of exposed embryos, tissue levels of tricyclic PAHs were below 1 micromol/kg, suggesting a specific, high affinity target in the heart. These findings have implications for understanding the mechanism of tricyclic PAH cardiotoxicity, the development of biomarkers for the effects of PAH exposure in fish, and understanding the long-term impacts of oil spills and other sources of PAH pollution in aquatic environments.

  13. Current Interventional and Surgical Management of Congenital Heart Disease: Specific Focus on Valvular Disease and Cardiac Arrhythmias.

    PubMed

    Holst, Kimberly A; Said, Sameh M; Nelson, Timothy J; Cannon, Bryan C; Dearani, Joseph A

    2017-03-17

    Successful outcome in the care of patients with congenital heart disease depends on a comprehensive multidisciplinary team. Surgery is offered for almost every heart defect, despite complexity. Early mortality for cardiac surgery in the neonatal period is ≈10% and beyond infancy is <5%, with 90% to 95% of patients surviving with a good quality of life into the adult years. Advances in imaging have facilitated accurate diagnosis and planning of interventions and surgical procedures. Similarly, advances in the perioperative medical management of patients, particularly with intensive care, has also contributed to improving outcomes. Arrhythmias and heart failure are the most common late complications for the majority of defects, and reoperation for valvar problems is common. Lifelong surveillance for monitoring of recurrent or residual structural heart defects, as well as periodic assessment of cardiac function and arrhythmia monitoring, is essential for all patients. The field of congenital heart surgery is poised to incorporate new innovations such as bioengineered cells and scaffolds that will iteratively move toward bioengineered patches, conduits, valves, and even whole organs.

  14. Pet ownership, social support, and one-year survival after acute myocardial infarction in the Cardiac Arrhythmia Suppression Trial (CAST).

    PubMed

    Friedmann, E; Thomas, S A

    1995-12-15

    Social support and pet ownership, a nonhuman form of social support, have both been associated with increased coronary artery disease survival. The independent effects of pet ownership, social support, disease severity, and other psychosocial factors on 1-year survival after acute myocardial infarction are examined prospectively. The Cardiac Arrhythmia Suppression Trial provided physiologic data on a group of post-myocardial infarction patients with asymptomatic ventricular arrhythmias. An ancillary study provided psychosocial data, including pet ownership, social support, recent life events, future life events, anxiety, depression, coronary prone behavior, and expression of anger. Subjects (n = 424) were randomly selected from patients attending participating Cardiac Arrhythmia Suppression Trial sites and completed baseline psychosocial questionnaires. One year survival data were obtained from 369 patients (87%), of whom 112 (30.4%) owned pets and 20 (5.4%) died. Logistic regression indicates that high social support (p < 0.068) and owning a pet (p = 0.085) tend to predict survival independent of physiologic severity and demographic and other psychosocial factors. Dog owners (n = 87, 1 died) are significantly less likely to die within 1 year than those who did not own dogs (n = 282, 19 died; p < 0.05); amount of social support is also an independent predictor of survival (p = 0.065). Both pet ownership and social support are significant predictors of survival, independent of the effects of the other psychosocial factors and physiologic status. These data confirm and extend previous findings relating pet ownership and social support to survival among patients with coronary artery disease.

  15. A study of the possible relation of the cardiac arrhythmias occurrence to the polarity reversal of the solar magnetic field

    NASA Astrophysics Data System (ADS)

    Mavromichalaki, H.; Preka-Papadema, P.; Theodoropoulou, A.; Paouris, E.; Apostolou, Th.

    2017-01-01

    The biological human system is probably affected by the solar and geomagnetic disturbances as well as the cosmic ray variations. In this work, the relation between the solar activity and cosmic ray variations and the cardiac arrhythmias over the time period 1997-2009 covering the solar cycle 23, is studied. The used medical data set refers to 4741 patients with cardiac arrhythmias and 2548 of whom were diagnosed with atrial fibrillation, obtained from the 2nd Cardiological Clinic of the General Hospital of Nicaea, Piraeus, in Greece. The smoothing method on a 365-day basis and the Pearson r-coefficient were used in order to compare these records with the number of sunspots, flares, solar proton events, coronal mass ejections and cosmic ray intensity. Applying a moving correlation function to ±1500 days, it is suggested that a change of the correlation sign between the medical data and each one of the above parameters occurs during a time interval of about 2-3 years. This interval corresponds to the time span of the polarity reversal of the solar magnetic field of this solar cycle, which always takes place around the solar cycle maximum. After then a correlation analysis was carried out corresponding to the rise (1997-2001) and the decay (2002-2009) phases of the solar cycle 23. It is noticeable that the polarity reversal of the solar magnetic field coincides with the period where the sign of the correlation between the incidence of arrhythmias and the occurrence number of the solar eruptive events and the cosmic ray intensity, changes sign. The results are comparable with those obtained from the previous solar cycle 22 based on medical data from another country.

  16. Association between Hypophosphatemia and Cardiac Arrhythmias in the Early Stage of Sepsis: Could Phosphorus Replacement Treatment Reduce the Incidence of Arrhythmias?

    PubMed

    Schwartz, Andrei; Brotfain, Evgeni; Koyfman, Leonid; Kutz, Ruslan; Gruenbaum, Shaun E; Klein, Moti; Zlotnik, Alexander

    2014-06-01

    It is well known that new-onset arrhythmias are common in septic patients. It is thought that hypophosphatemia in the early stages of sepsis may contribute to the development of new arrhythmias. In this study, we hypothesized that intravenous (IV) phosphorus replacement may reduce the incidence of arrhythmias in critically ill patients. 34 adult septic patients with hypophosphatemia admitted to the general intensive care unit were treated with IV phosphorus replacement per ICU protocol, and the incidence of new arrhythmias were compared with 16 patients from previously published data. IV phosphorus replacement was associated with a significantly reduced incidence of arrhythmias (38% vs. 63%, p=0.04). There were no differences in observed mortality between subgroups, which may be due to the small sample size. This study demonstrated that IV phosphorus replacement might be effective in reducing the incidence of new arrhythmias in septic patients.

  17. Examining the role of TRPA1 in air pollution-induced cardiac arrhythmias and autonomic imbalance

    EPA Science Inventory

    Here we describe how air pollution causes cardiac arrhythmogenesis through sensory irritation in the airways. Time-series studies show the risk of adverse cardiac events increases significantly in the hours to days after expos...

  18. Influence of electromagnetic interference on implanted cardiac arrhythmia devices in and around a magnetically levitated linear motor car.

    PubMed

    Fukuta, Motoyuki; Mizutani, Noboru; Waseda, Katsuhisa

    2005-01-01

    This study was designed to determine the susceptibility of implanted cardiac arrhythmia devices to electromagnetic interference in and around a magnetically levitated linear motor car [High-Speed Surface Transport (HSST)]. During the study, cardiac devices were connected to a phantom model that had similar characteristics to the human body. Three pacemakers from three manufacturers and one implantable cardioverter-defibrillator (ICD) were evaluated in and around the magnetically levitated vehicle. The system is based on a normal conductive system levitated by the attractive force of magnets and propelled by a linear induction motor without wheels. The magnetic field strength at 40 cm from the vehicle in the nonlevitating state was 0.12 mT and that during levitation was 0.20 mT. The magnetic and electric field strengths on a seat close to the variable voltage/variable frequency inverter while the vehicle was moving and at rest were 0.13 mT, 2.95 V/m and 0.04 mT, 0.36 V/m, respectively. Data recorded on a seat close to the reactor while the vehicle was moving and at rest were 0.09 mT, 2.45 V/m and 0.05 mT, 1.46 V/m, respectively. Measured magnetic and electric field strengths both inside and outside the linear motor car were too low to result in device inactivation. No sensing, pacing, or arrhythmic interactions were noted with any pacemaker or ICD programmed in either bipolar and unipolar configurations. In conclusion, our data suggest that a permanent programming change or a device failure is unlikely to occur and that the linear motor car system is probably safe for patients with one of the four implanted cardiac arrhythmia devices used in this study under the conditions tested.

  19. Characterization of Cardiac Anoctamin1 Ca2+-Activated Chloride Channels and Functional Role in Ischemia-Induced Arrhythmias

    PubMed Central

    Ye, Zhen; Wu, Ming-Ming; Wang, Chun-Yu; Li, Yan-Chao; Yu, Chang-Jiang; Gong, Yuan-Feng; Zhang, Jun; Wang, Qiu-Shi; Song, Bin-Lin; Yu, Kuai; Hartzell, H. Criss; Duan, Dayue Darrel; Zhao, Dan; Zhang, Zhi-Ren

    2015-01-01

    Anoctamin1 (ANO1) encodes a Ca2+-activated chloride (Cl−) channel (CaCC) in variety tissues of many species. Whether ANO1 expresses and functions as a CaCC in cardiomyocytes remain unknown. The objective of this study is to characterize the molecular and functional expression of ANO1 in cardiac myocytes and the role of ANO1-encoded CaCCs in ischemia-induced arrhythmias in the heart. Quantitative real-time RT-PCR, immunofluorescence staining assays, and immunohistochemistry identified the molecular expression, location, and distribution of ANO1 in mouse ventricular myocytes (mVMs). Patch-clamp recordings combined with pharmacological analyses found that ANO1 was responsible for a Ca2+-activated Cl− current (ICl.Ca) in cardiomyocytes. Myocardial ischemia led to a significant increase in the current density of ICl.Ca, which was inhibited by a specific ANO1 inhibitor, T16Ainh-A01, and an antibody targeting at the pore area of ANO1. Moreover, cardiomyocytes isolated from mice with ischemia-induced arrhythmias had an accelerated early phase 1 repolarization of action potentials (APs) and a deeper “spike and dome” compared to control cardiomyocytes from non-ischemia mice. Application of the antibody targeting at ANO1 pore prevented the ischemia-induced early phase 1 repolarization acceleration and caused a much shallower “spike and dome”. We conclude that ANO1 encodes CaCC and plays a significant role in the phase 1 repolarization of APs in mVMs. The ischemia-induced increase in ANO1 expression may be responsible for the increased density of ICl.Ca in the ischemic heart and may contribute, at least in part, to ischemia-induced arrhythmias. PMID:24962810

  20. The effects of B0, B20 and B100 soy biodiesel exhaust on aconitine-induced cardiac arrhythmia in spontaneously hypertensive rats

    EPA Science Inventory

    CONTEXT: Diesel exhaust (DE) has been shown to increase the risk of cardiac arrhythmias. Although biodiesel has been proposed as a "safer" alternative to diesel, it is still uncertain whether it actually poses less threat.OBJECTIVE: We hypothesized that exposure to pure or 20% so...

  1. Assessment of Cardiac Rate and Rhythm in Fetuses with Arrhythmia via Maternal Abdominal Fetal Electrocardiography

    PubMed Central

    Narayan, Hari K.; Vignola, Emilia F.; Fifer, William P.; Williams, Ismee A.

    2015-01-01

    Objective This study aims to report our experience using the Monica AN24 (Monica Healthcare Ltd., Nottingham, United Kingdom), a maternal transabdominal fetal electrocardiographic monitor, in a case series of fetuses with arrhythmias. Study Design We recorded fetal electrocardiograms (fECGs) on subjects with fetal arrhythmias diagnosed by fetal echocardiogram. Fetal heart rate and rhythm were determined via manual fECG analysis. Results Overall, 20 fECGs were recorded from a pool of 13 subjects. Fetal heart rate acquisition was determined to be high, medium, and poor quality in 10, 3, and 7 tracings, respectively. High-quality tracings were obtained in 9 of 11 subjects with gestational age < 26 or > 34 weeks. P waves were detectable in five tracings. Conclusion In subjects < 26 or > 34 weeks' gestational age, there was reasonable success in fetal heart rate acquisition. Further study is warranted to determine the potential role of this device in the monitoring of subjects with fetal arrhythmias. PMID:26495180

  2. Registry of Malignant Arrhythmias and Sudden Cardiac Death - Influence of Diagnostics and Interventions

    ClinicalTrials.gov

    2016-11-30

    Ventricular Tachycardia; Ventricular Fibrillation; Sudden Cardiac Death; Coronary Angiography; Electrophysiologic Testing (EP); Catheter Ablation; Percutaneous Coronary Intervention (PCI); Internal Cardioverter Defibrillator (ICD)

  3. Wideband Arrhythmia-Insensitive-Rapid (AIR) Pulse Sequence for Cardiac T1 mapping without Image Artifacts induced by ICD

    PubMed Central

    Hong, KyungPyo; Jeong, Eun-Kee; Wall, T. Scott; Drakos, Stavros G.; Kim, Daniel

    2015-01-01

    Purpose To develop and evaluate a wideband arrhythmia-insensitive-rapid (AIR) pulse sequence for cardiac T1 mapping without image artifacts induced by implantable-cardioverter-defibrillator (ICD). Methods We developed a wideband AIR pulse sequence by incorporating a saturation pulse with wide frequency bandwidth (8.9 kHz), in order to achieve uniform T1 weighting in the heart with ICD. We tested the performance of original and “wideband” AIR cardiac T1 mapping pulse sequences in phantom and human experiments at 1.5T. Results In 5 phantoms representing native myocardium and blood and post-contrast blood/tissue T1 values, compared with the control T1 values measured with an inversion-recovery pulse sequence without ICD, T1 values measured with original AIR with ICD were considerably lower (absolute percent error >29%), whereas T1 values measured with wideband AIR with ICD were similar (absolute percent error <5%). Similarly, in 11 human subjects, compared with the control T1 values measured with original AIR without ICD, T1 measured with original AIR with ICD was significantly lower (absolute percent error >10.1%), whereas T1 measured with wideband AIR with ICD was similar (absolute percent error <2.0%). Conclusion This study demonstrates the feasibility of a wideband pulse sequence for cardiac T1 mapping without significant image artifacts induced by ICD. PMID:25975192

  4. The power of exercise-induced T-wave alternans to predict ventricular arrhythmias in patients with implanted cardiac defibrillator.

    PubMed

    Burattini, Laura; Man, Sumche; Sweene, Cees A

    2013-01-01

    The power of exercise-induced T-wave alternans (TWA) to predict the occurrence of ventricular arrhythmias was evaluated in 67 patients with an implanted cardiac defibrillator (ICD). During the 4-year follow-up, electrocardiographic (ECG) tracings were recorded in a bicycle ergometer test with increasing workload ranging from zero (NoWL) to the patient's maximal capacity (MaxWL). After the follow-up, patients were classified as either ICD_Cases (n = 29), if developed ventricular tachycardia/fibrillation, or ICD_Controls (n = 38). TWA was quantified using our heart-rate adaptive match filter. Compared to NoWL, MaxWL was characterized by faster heart rates and higher TWA in both ICD_Cases (12-18 μ V vs. 20-39 μ V; P < 0.05) and ICD_Controls (9-15 μ V vs. 20-32 μ V; P < 0.05). Still, TWA was able to discriminate the two ICD groups during NoWL (sensitivity = 59-83%, specificity = 53-84%) but not MaxWL (sensitivity = 55-69%, specificity = 39-74%). Thus, this retrospective observational case-control study suggests that TWA's predictive power for the occurrence of ventricular arrhythmias could increase at low heart rates.

  5. Wenxin-Keli Regulates the Calcium/Calmodulin-Dependent Protein Kinase II Signal Transduction Pathway and Inhibits Cardiac Arrhythmia in Rats with Myocardial Infarction

    PubMed Central

    Xing, Yanwei; Gao, Yonghong; Chen, Jianxin; Zhu, Haiyan; Wu, Aiming; Yang, Qing; Teng, Fei; Zhang, Dong-mei; Xing, Yanhui; Gao, Kuo; He, Qingyong; Zhang, Zhenpeng; Wang, Jie; Shang, Hongcai

    2013-01-01

    Wenxin-Keli (WXKL) is a Chinese herbal compound reported to be of benefit in the treatment of cardiac arrhythmia, cardiac inflammation, and heart failure. Amiodarone is a noncompetitive inhibitor of the α- and β-adrenergic receptors and prevents calcium influx in the slow-response cells of the sinoatrial and atrioventricular nodes. Overexpression of Ca2+/calmodulin-dependent protein kinase II (CaMKII) in transgenic mice results in heart failure and arrhythmias. We hypothesised that administration of WXKL and amiodarone can reduce the incidence of arrhythmias by regulating CaMKII signal transduction. A total of 100 healthy Sprague Dawley rats were used in the study. The rats were randomly divided into four groups (a sham group, a myocardial infarction (MI) group, a WXKL-treated group, and an amiodarone-treated group). A myocardial infarction model was established in these rats by ligating the left anterior descending coronary artery for 4 weeks. Western blotting was used to assess CaMKII, p-CaMKII (Thr-286), PLB, p-PLB (Thr-17), RYR2, and FK binding protein 12.6 (FKBP12.6) levels. The Ca2+ content in the sarcoplasmic reticulum (SR) and the calcium transient amplitude were studied by confocal imaging using the fluorescent indicator Fura-4. In conclusion, WXKL may inhibit heart failure and cardiac arrhythmias by regulating the CaMKII signal transduction pathway similar to amiodarone. PMID:23781262

  6. Wenxin-Keli Regulates the Calcium/Calmodulin-Dependent Protein Kinase II Signal Transduction Pathway and Inhibits Cardiac Arrhythmia in Rats with Myocardial Infarction.

    PubMed

    Xing, Yanwei; Gao, Yonghong; Chen, Jianxin; Zhu, Haiyan; Wu, Aiming; Yang, Qing; Teng, Fei; Zhang, Dong-Mei; Xing, Yanhui; Gao, Kuo; He, Qingyong; Zhang, Zhenpeng; Wang, Jie; Shang, Hongcai

    2013-01-01

    Wenxin-Keli (WXKL) is a Chinese herbal compound reported to be of benefit in the treatment of cardiac arrhythmia, cardiac inflammation, and heart failure. Amiodarone is a noncompetitive inhibitor of the α - and β -adrenergic receptors and prevents calcium influx in the slow-response cells of the sinoatrial and atrioventricular nodes. Overexpression of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) in transgenic mice results in heart failure and arrhythmias. We hypothesised that administration of WXKL and amiodarone can reduce the incidence of arrhythmias by regulating CaMKII signal transduction. A total of 100 healthy Sprague Dawley rats were used in the study. The rats were randomly divided into four groups (a sham group, a myocardial infarction (MI) group, a WXKL-treated group, and an amiodarone-treated group). A myocardial infarction model was established in these rats by ligating the left anterior descending coronary artery for 4 weeks. Western blotting was used to assess CaMKII, p-CaMKII (Thr-286), PLB, p-PLB (Thr-17), RYR2, and FK binding protein 12.6 (FKBP12.6) levels. The Ca(2+) content in the sarcoplasmic reticulum (SR) and the calcium transient amplitude were studied by confocal imaging using the fluorescent indicator Fura-4. In conclusion, WXKL may inhibit heart failure and cardiac arrhythmias by regulating the CaMKII signal transduction pathway similar to amiodarone.

  7. About Arrhythmia

    MedlinePlus

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More About Arrhythmia Updated:Oct 26,2016 The term "arrhythmia" refers ... damaged. View an animation of arrhythmia . Types of Arrhythmias Atrial Fibrillation = upper heart chambers contract irregularly Bradycardia = ...

  8. Arrhythmias After Fontan Operation with Intra-atrial Lateral Tunnel Versus Extra-cardiac Conduit: A Systematic Review and Meta-analysis.

    PubMed

    Li, Dongxu; Fan, Qiang; Hirata, Yasutaka; Ono, Minoru; An, Qi

    2017-03-07

    Current studies on the incidence of arrhythmias after the intra-atrial lateral tunnel (ILT) Fontan operation and the extra-cardiac conduit (ECC) Fontan operation are limited, with controversial results. This systematic review aimed to compare the prevalence of arrhythmias in patients who underwent ECC or ILT Fontan. Relevant studies comparing the incidence of arrhythmias and pacemaker implantation in ILT with ECC were identified through a literature search using MEDLINE, EMBASE, and the cochrane central register of controlled trials. The outcome measures included baseline characteristics, early (≤30 days) and late (>30 days) arrhythmias and pacemaker implantation. 16 publications involving 3499 patients were included. In the meta-analysis, although the overall risk of early arrhythmias was lower for the ILT group, statistically, no significant difference was observed (odds ratio [OR] 0.78; 95% confidence interval [CI] 0.61-1.01; p = 0.06). Similarly, there was no significant difference between the two cohorts in the incidence of postoperative permanent pacemaker therapy (OR 1.36; 95% CI 0.86-2.14; p = 0.19). However, we found significantly increased incidence of late arrhythmias in ILT group compared with ECC group (OR 1.96; 95% CI 1.64-2.35; p < 0.01). Although our systematic review and meta-analysis suggested that there was no significant difference in early arrhythmias and in pacemaker implantation between the ILT and ECC groups, ECC procedure could significantly lower the risk of late arrhythmias after Fontan surgery. Given that some limitations cannot be overcome, well-designed randomized controlled trials are needed to confirm our findings.

  9. Safe Oral Triiodo-L-Thyronine Therapy Protects from Post-Infarct Cardiac Dysfunction and Arrhythmias without Cardiovascular Adverse Effects

    PubMed Central

    Rajagopalan, Viswanathan; Zhang, Youhua; Ojamaa, Kaie; Chen, Yue-feng; Pingitore, Alessandro; Pol, Christine J.; Saunders, Debra; Balasubramanian, Krithika; Towner, Rheal A.; Gerdes, A. Martin

    2016-01-01

    Background A large body of evidence suggests that thyroid hormones (THs) are beneficial for the treatment of cardiovascular disorders. We have shown that 3 days of triiodo-L-thyronine (T3) treatment in myocardial infarction (MI) rats increased left ventricular (LV) contractility and decreased myocyte apoptosis. However, no clinically translatable protocol is established for T3 treatment of ischemic heart disease. We hypothesized that low-dose oral T3 will offer safe therapeutic benefits in MI. Methods and Results Adult female rats underwent left coronary artery ligation or sham surgeries. T3 (~6 μg/kg/day) was available in drinking water ad libitum immediately following MI and continuing for 2 month(s) (mo). Compared to vehicle-treated MI, the oral T3-treated MI group at 2 mo had markedly improved anesthetized Magnetic Resonance Imaging-based LV ejection fraction and volumes without significant negative changes in heart rate, serum TH levels or heart weight, indicating safe therapy. Remarkably, T3 decreased the incidence of inducible atrial tachyarrhythmias by 88% and improved remodeling. These were accompanied by restoration of gene expression involving several key pathways including thyroid, ion channels, fibrosis, sympathetic, mitochondria and autophagy. Conclusions Low-dose oral T3 dramatically improved post-MI cardiac performance, decreased atrial arrhythmias and cardiac remodeling, and reversed many adverse changes in gene expression with no observable negative effects. This study also provides a safe and effective treatment/monitoring protocol that should readily translate to humans. PMID:26981865

  10. Real-Time Cardiac Arrhythmia Detection Using WOLA Filterbank Analysis of EGM Signals

    NASA Astrophysics Data System (ADS)

    Sheikhzadeh, Hamid; Brennan, Robert L.; So, Simon

    2007-12-01

    Novel methods of cardiac rhythm detection are proposed that are based on time-frequency analysis by a weighted overlap-add (WOLA) oversampled filterbank. Cardiac signals are obtained from intracardiac electrograms and decomposed into the time-frequency domain and analyzed by parallel peak detectors in selected frequency subbands. The coherence (synchrony) of the subband peaks is analyzed and employed to detect an optimal peak sequence representing the beat locations. By further analysis of the synchrony of the subband beats and the periodicity and regularity of the optimal beat, various possible cardiac events (including fibrillation, flutter, and tachycardia) are detected. The Ann Arbor Electrogram Library is used to evaluate the proposed detection method in clean and in additive noise. The evaluation results show that the method never misses any episode of fibrillation or flutter in clean or in noise and is robust to far-field R-wave interference. Furthermore, all other misclassification errors were within the acceptable limits.

  11. High g-Force Rollercoaster Rides Induce Sinus Tachycardia but No Cardiac Arrhythmias in Healthy Children.

    PubMed

    Pieles, Guido E; Husk, Victoria; Blackwell, Teresa; Wilson, Deirdre; Collin, Simon M; Williams, Craig A; Stuart, A Graham

    2017-01-01

    Theme park operators and medical professionals advise children with heart conditions against using rollercoaster rides, but these recommendations are not evidence-based. The underlying assumption is that the combination of adrenergic stimulation through stress and acceleration might trigger arrhythmias in susceptible individuals. We conducted a cross-sectional observational study to assess heart rate and rhythm in healthy children during commercial rollercoaster rides. Twenty healthy children (9 male) aged 11-15 (mean 13.3 ± 1.4) years underwent continuous heart rate and rhythm monitoring (2-lead ECG) from 5 min before until 10 min after each of 4 high speed (>50 km h(-1)), high g-force (>4) commercial rollercoaster rides. Total recording time was 13 h 20 min. No arrhythmic events were detected. Resting heart rate was 81 ± 10 b min(-1) and increased to 158 ± 20 b·min(-1) during rides. The highest mean HR (165 ± 23 b min(-1)) was observed on the ride with the lowest g-force (4.5 g), but one of the highest speeds (100 km h(-1)). Anticipatory tachycardia (126 ± 15 b min(-1)) within 5 min was frequently observed. A 10 min recovery HR (124 ± 17 b min(-1)) was 56 % greater than resting HR. The speed and g-force experienced on roller coasters induce sinus tachycardia but do not elicit pathological arrhythmias in healthy children.

  12. Derivation of Human Induced Pluripotent Stem (iPS) Cells to Heritable Cardiac Arrhythmias

    ClinicalTrials.gov

    2016-03-14

    Inherited Cardiac Arrythmias; Long QT Syndrome (LQTS); Brugada Syndrome (BrS); Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT); Early Repolarization Syndrome (ERS); Arrhythmogenic Cardiomyopathy (AC, ARVD/C); Hypertrophic Cardiomyopathy (HCM); Dilated Cardiomyopathy (DCM); Muscular Dystrophies (Duchenne, Becker, Myotonic Dystrophy); Normal Control Subjects

  13. Mitochondria and Arrhythmias

    PubMed Central

    Yang, Kai-Chien; Bonini, Marcelo G.; Dudley, Samuel C.

    2014-01-01

    Mitochondria are essential to providing ATP thereby satisfying the energy demand of the incessant electrical activity and contractile action of cardiac muscle. Emerging evidence indicates that mitochondrial dysfunction can adversely impact cardiac electrical functioning by impairing the intracellular ion homeostasis and membrane excitability through reduced ATP production and excessive reactive oxidative species (ROS) generation, resulting in increased propensity to cardiac arrhythmias. In this review, the molecular mechanisms linking mitochondrial dysfunction to cardiac arrhythmias are discussed with an emphasis on the impact of increased mitochondrial ROS on the cardiac ion channels and transporters that are critical to maintaining normal electromechanical functioning of the cardiomyocytes. The potential of using mitochondria-targeted antioxidants as a novel anti-arrhythmia therapy is highlighted. PMID:24713422

  14. Mosaic Deficiency in Mitochondrial Oxidative Metabolism Promotes Cardiac Arrhythmia during Aging.

    PubMed

    Baris, Olivier R; Ederer, Stefan; Neuhaus, Johannes F G; von Kleist-Retzow, Jürgen-Christoph; Wunderlich, Claudia M; Pal, Martin; Wunderlich, F Thomas; Peeva, Viktoriya; Zsurka, Gabor; Kunz, Wolfram S; Hickethier, Tilman; Bunck, Alexander C; Stöckigt, Florian; Schrickel, Jan W; Wiesner, Rudolf J

    2015-05-05

    Aging is a progressive decline of body function, during which many tissues accumulate few cells with high levels of deleted mitochondrial DNA (mtDNA), leading to a defect of mitochondrial functions. Whether this mosaic mitochondrial deficiency contributes to organ dysfunction is unknown. To investigate this, we generated mice with an accelerated accumulation of mtDNA deletions in the myocardium, by expressing a dominant-negative mutant mitochondrial helicase. These animals accumulated few randomly distributed cardiomyocytes with compromised mitochondrial function, which led to spontaneous ventricular premature contractions and AV blocks at 18 months. These symptoms were not caused by a general mitochondrial dysfunction in the entire myocardium, and were not observed in mice at 12 months with significantly lower numbers of dysfunctional cells. Therefore, our results suggest that the disposition to arrhythmia typically found in the aged human heart might be due to the random accumulation of mtDNA deletions and the subsequent mosaic respiratory chain deficiency.

  15. Complexity-Measure-Based Sequential Hypothesis Testing for Real-Time Detection of Lethal Cardiac Arrhythmias

    NASA Astrophysics Data System (ADS)

    Chen, Szi-Wen

    2006-12-01

    A novel approach that employs a complexity-based sequential hypothesis testing (SHT) technique for real-time detection of ventricular fibrillation (VF) and ventricular tachycardia (VT) is presented. A dataset consisting of a number of VF and VT electrocardiogram (ECG) recordings drawn from the MIT-BIH database was adopted for such an analysis. It was split into two smaller datasets for algorithm training and testing, respectively. Each ECG recording was measured in a 10-second interval. For each recording, a number of overlapping windowed ECG data segments were obtained by shifting a 5-second window by a step of 1 second. During the windowing process, the complexity measure (CM) value was calculated for each windowed segment and the task of pattern recognition was then sequentially performed by the SHT procedure. A preliminary test conducted using the database produced optimal overall predictive accuracy of[InlineEquation not available: see fulltext.]. The algorithm was also implemented on a commercial embedded DSP controller, permitting a hardware realization of real-time ventricular arrhythmia detection.

  16. Suppressing arrhythmias in cardiac models using overdrive pacing and calcium channel blockers

    NASA Astrophysics Data System (ADS)

    Stamp, A. T.; Osipov, G. V.; Collins, J. J.

    2002-09-01

    Recent findings indicate that ventricular fibrillation might arise from spiral wave chaos. Our objective in this computational study was to investigate wave interactions in excitable media and to explore the feasibility of using overdrive pacing to suppress spiral wave chaos. This work is based on the finding that in excitable media, propagating waves with the highest excitation frequency eventually overtake all other waves. We analyzed the effects of low-amplitude, high-frequency pacing in one-dimensional and two-dimensional networks of coupled, excitable cells governed by the Luo-Rudy model. In the one-dimensional cardiac model, we found narrow high-frequency regions of 1:1 synchronization between the input stimulus and the system's response. The frequencies in this region were higher than the intrinsic spiral wave frequency of cardiac tissue. When we paced the two-dimensional cardiac model with frequencies from this region, we found that spiral wave chaos could, in some cases, be suppressed. When we coupled the overdrive pacing with calcium channel blockers, we found that spiral wave chaos could be suppressed in all cases. These findings suggest that low-amplitude, high-frequency overdrive pacing, in combination with calcium channel inhibitors (e.g., class II or class IV antiarrhythmic drugs), may be useful for eliminating fibrillation.

  17. Use of an Implantable Loop Recorder in a Chimpanzee (Pan troglodytes) to Monitor Cardiac Arrhythmias and Assess the Effects of Acupuncture and Laser Therapy

    PubMed Central

    Magden, Elizabeth R; Sleeper, Meg M; Buchl, Stephanie J; Jones, Rebekah A; Thiele, Erica J; Wilkerson, Gregory K

    2016-01-01

    Cardiovascular disease is a leading cause of death in captive chimpanzees and is often associated with myocardial fibrosis, which increases the risk of cardiac arrhythmias. In this case report, we present a 36-y-old male chimpanzee (Pan troglodytes) diagnosed with frequent ventricular premature complexes (VPC). We placed a subcutaneous implantable loop recorder for continual ECG monitoring to assess his arrhythmias without the confounding effects of anesthetics. During his initial treatment with the antiarrhythmia medication amiodarone, he developed thrombocytopenia, and the drug was discontinued. After reviewing other potential therapies for the treatment of cardiac arrhythmias, we elected to try acupuncture and laser therapy in view of the positive results and the lack of adverse side effects reported in humans. We used 2 well-known cardiac acupuncture sites on the wrist, PC6 (pericardium 6) and HT7 (heart 7), and evaluated the results of the therapy by using the ECG recordings from the implantable loop recorder. Although periodic increases in the animal's excitement level introduced confounding variables that caused some variation in the data, acupuncture and laser therapy appeared to decrease the mean number of VPC/min in this chimpanzee. PMID:26884410

  18. Use of an Implantable Loop Recorder in a Chimpanzee (Pan troglodytes) to Monitor Cardiac Arrhythmias and Assess the Effects of Acupuncture and Laser Therapy.

    PubMed

    Magden, Elizabeth R; Sleeper, Meg M; Buchl, Stephanie J; Jones, Rebekah A; Thiele, Erica J; Wilkerson, Gregory K

    2016-02-01

    Cardiovascular disease is a leading cause of death in captive chimpanzees and is often associated with myocardial fibrosis, which increases the risk of cardiac arrhythmias. In this case report, we present a 36-y-old male chimpanzee (Pan troglodytes) diagnosed with frequent ventricular premature complexes (VPC). We placed a subcutaneous implantable loop recorder for continual ECG monitoring to assess his arrhythmias without the confounding effects of anesthetics. During his initial treatment with the antiarrhythmia medication amiodarone, he developed thrombocytopenia, and the drug was discontinued. After reviewing other potential therapies for the treatment of cardiac arrhythmias, we elected to try acupuncture and laser therapy in view of the positive results and the lack of adverse side effects reported in humans. We used 2 well-known cardiac acupuncture sites on the wrist, PC6 (pericardium 6) and HT7 (heart 7), and evaluated the results of the therapy by using the ECG recordings from the implantable loop recorder. Although periodic increases in the animal's excitement level introduced confounding variables that caused some variation in the data, acupuncture and laser therapy appeared to decrease the mean number of VPC/min in this chimpanzee.

  19. Effect of regional differences in cardiac cellular electrophysiology on the stability of ventricular arrhythmias: a computational study

    NASA Astrophysics Data System (ADS)

    Clayton, Richard H.; Holden, Arun V.

    2003-01-01

    Re-entry is an important mechanism of cardiac arrhythmias. During re-entry a wave of electrical activation repeatedly propagates into recovered tissue, rotating around a rod-like filament. Breakdown of a single re-entrant wave into multiple waves is believed to underlie the transition from ventricular tachycardia to ventricular fibrillation. Several mechanisms of breakup have been identified including the effect of anisotropic conduction in the ventricular wall. Cells in the inner and outer layers of the ventricular wall have different action potential durations (APD), and support re-entrant waves with different periods. The aim of this study was to use a computational approach to study twisting and breakdown in a transmural re-entrant wave spanning these regions, and examine the relative role of this effect and anisotropic conduction. We used a simplified model of action potential conduction in the ventricular wall that we modified so that it supported stable re-entry in an anisotropic model with uniform APD. We first examined the effect of regional differences on breakdown in an isotropic model with transmural differences in APD, and found that twisting of the re-entrant filament resulted in buckling and breakdown during the second cycle of re-entry. We found that breakdown was amplified in the anisotropic model, resulting in complex activation in the region of longest APD. This study shows that regional differences in cardiac electrophysiology are a potentially important mechanism for destabilizing re-entry and may act synergistically with other mechanisms to mediate the transition from ventricular tachycardia to ventricular fibrillation.

  20. [State-of-the-art and prospects of high-tech medical aid to patients with cardiac arrhythmia based at military medical facilities].

    PubMed

    Steklov, V I

    2014-01-01

    Analysis of provision of high-tech medical aid to patients with cardiac arrhythmia based at military medical facilities showed that the available means and workforce are sufficient for the purpose. In order to facilitate access to high-tech medical aid it is necessary to equip arrhythmologic departments with up-to-date-instruments and set up cabinets of electrocardiostimulation in regional (naval) hospitals for implantation of temporary and permanent pacemakers. A program is pending for education (primary specialization) and advanced training of specialists in clinical cardiac electrophysiology, interventional and surgical arrhythmology.

  1. Effects of Acupuncture at the Yintang and the Chengjiang Acupoints on Cardiac Arrhythmias and Neurocardiogenic Syncope in Emergency First Aid.

    PubMed

    Fabrin, Saulo; Soares, Nayara; Pezarezi Yoshimura, Daiana; Hallak Regalo, Simone Cecilio; Donizetti Verri, Edson; de Freitas Vianna, Jacqueline Rodrigues; Gatti Regueiro, Eloisa Maria; Torres da Silva, Josie Resende

    2016-02-01

    This study evaluated the effectiveness of YinTang and ChengJiang acupoints on patients with cardiac arrhythmia and neurocardiogenic syncope in emergency first aid. A 45 year old woman underwent acupuncture. She had a previous history of a valvuloplasty for rheumatic disease and two acute myocardial infarctions, followed by four catheterizations and an angioplasty. Needling of the YinTang acupoint and stimulation of the ChengJiang acupoint through acupressure were performed for 20 minutes soon after syncope and during tachycardia, hypertension, tachypnea, and precordial pain, without any effect on peripheral oxygen saturation (SpO2) or the glycemic index. Data were analyzed comparatively by using the following parameters at rest, during syncope, and at 1 minute and 10 minutes after an emergency acupuncture procedure: blood pressure; heart rate; SpO2; and respiratory rate. We found that acupuncture at YinTang and ChenJiang acupoints induced cardiovascular responses, increased the limits of the body's homeostasis, and normalized the patient's condition in the case of syncope. Acupuncture using a combination of ChengJiang and YinTang acupoints had an immediate effect on the autonomic nervous system and on maintaining homeostasis and energy balance in the body. Although this technique was effective, the patient was still referred to the Emergency Room.

  2. Symbolic dynamics for arrhythmia identification from heart variability of rats with cardiac failures

    NASA Astrophysics Data System (ADS)

    Letellier, C.; Roulin, E.; Loriot, S.; Morin, J.-P.; Dionnet, F.

    2004-12-01

    Heart rate variability of rats is investigated using concepts from the nonlinear dynamical system theory. Among the important techniques offered, symbolic dynamics is very appealing by its power to investigate patterns which can be repeated in a time series. The present analysis was performed in six control rats and six chronic cardiac insufficient rats (myocardial infarction due to left descendent coronary artery ligation). Rats are left in clean atmosphere or exposed to atmosphere containing diluted engine emission pollutants. The evolution of the heart rate variability is then investigated with a three element symbolic dynamics which allows to distinguish extrasystoles from tachycardia or bradycardia using the symbol sequences.

  3. Implications of the Turing completeness of reaction-diffusion models, informed by GPGPU simulations on an XBox 360: cardiac arrhythmias, re-entry and the Halting problem.

    PubMed

    Scarle, Simon

    2009-08-01

    In the arsenal of tools that a computational modeller can bring to bare on the study of cardiac arrhythmias, the most widely used and arguably the most successful is that of an excitable medium, a special case of a reaction-diffusion model. These are used to simulate the internal chemical reactions of a cardiac cell and the diffusion of their membrane voltages. Via a number of different methodologies it has previously been shown that reaction-diffusion systems are at multiple levels Turing complete. That is, they are capable of computation in the same manner as a universal Turing machine. However, all such computational systems are subject to a limitation known as the Halting problem. By constructing a universal logic gate using a cardiac cell model, we highlight how the Halting problem therefore could limit what it is possible to predict about cardiac tissue, arrhythmias and re-entry. All simulations for this work were carried out on the GPU of an XBox 360 development console, and we also highlight the great gains in computational power and efficiency produced by such general purpose processing on a GPU for cardiac simulations.

  4. Almanac 2013: cardiac arrhythmias and pacing--an editorial overview of selected research that has driven recent advances in clinical cardiology.

    PubMed

    Liew, Reginald

    2014-04-01

    Important advances have been made in the past few years in the fields of clinical cardiac electrophysiology and pacing. Researchers and clinicians have a greater understanding of the pathophysiological mechanisms underlying atrial fibrillation (AF), which has transpired into improved methods of detection, risk stratification, and treatments. The introduction of novel oral anticoagulants has provided clinicians with alternative options in managing patients with AF at moderate to high thromboembolic risk and further data has been emerging on the use of catheter ablation for the treatment of symptomatic AF. Another area of intense research in the field of cardiac arrhythmias and pacing is in the use of cardiac resynchronisation therapy (CRT) for the treatment of patients with heart failure. Following the publication of major landmark randomised controlled trials reporting that CRT confers a survival advantage in patients with severe heart failure and improves symptoms, many subsequent studies have been performed to further refine the selection of patients for CRT and determine the clinical characteristics associated with a favourable response. The field of sudden cardiac death and implantable cardioverter defibrillators also continues to be actively researched, with important new epidemiological and clinical data emerging on improved methods for patient selection, risk stratification, and management.This review covers the major recent advances in these areas related to cardiac arrhythmias and pacing.

  5. Intraoperative management of critical arrhythmia

    PubMed Central

    2017-01-01

    The incidence of intraoperative arrhythmia is extremely high, and some arrhythmias require clinical attention. Therefore, it is essential for the anesthesiologist to evaluate risk factors for arrhythmia and understand their etiology, electrophysiology, diagnosis, and treatment. Anesthetic agents reportedly affect normal cardiac electrical activity. In the normal cardiac cycle, the sinoatrial node initiates cardiac electrical activity through intrinsic autonomous pacemaker activity. Sequential atrial and ventricular contractions result in an effective cardiac pumping mechanism. Arrhythmia occurs due to various causes, and the cardiac pumping mechanism may be affected. A severe case may result in hemodynamic instability. In this situation, the anesthesiologist should eliminate the possible causes of arrhythmia and manage the condition, creating hemodynamic stability under proper electrocardiographic monitoring. PMID:28367281

  6. Modifying L-type calcium current kinetics: consequences for cardiac excitation and arrhythmia dynamics.

    PubMed

    Mahajan, Aman; Sato, Daisuke; Shiferaw, Yohannes; Baher, Ali; Xie, Lai-Hua; Peralta, Robert; Olcese, Riccardo; Garfinkel, Alan; Qu, Zhilin; Weiss, James N

    2008-01-15

    The L-type Ca current (I(Ca,L)), essential for normal cardiac function, also regulates dynamic action potential (AP) properties that promote ventricular fibrillation. Blocking I(Ca,L) can prevent ventricular fibrillation, but only at levels suppressing contractility. We speculated that, instead of blocking I(Ca,L), modifying its shape by altering kinetic features could produce equivalent anti-fibrillatory effects without depressing contractility. To test this concept experimentally, we overexpressed a mutant Ca-insensitive calmodulin (CaM(1234)) in rabbit ventricular myocytes to inhibit Ca-dependent I(Ca,L) inactivation, combined with the ATP-sensitive K current agonist pinacidil or I(Ca,L) blocker verapamil to maintain AP duration (APD) near control levels. Cell shortening was enhanced in pinacidil-treated myocytes, but depressed in verapamil-treated myocytes. Both combinations flattened APD restitution slope and prevented APD alternans, similar to I(Ca,L) blockade. To predict the arrhythmogenic consequences, we simulated the cellular effects using a new AP model, which reproduced flattening of APD restitution slope and prevention of APD/Ca(i) transient alternans but maintained a normal Ca(i) transient. In simulated two-dimensional cardiac tissue, these changes prevented the arrhythmogenic spatially discordant APD/Ca(i) transient alternans and spiral wave breakup. These findings provide a proof-of-concept test that I(Ca,L) can be targeted to increase dynamic wave stability without depressing contractility, which may have promise as an antifibrillatory strategy.

  7. Sarcomere mechanics in uniform and non-uniform cardiac muscle: a link between pump function and arrhythmias.

    PubMed

    ter Keurs, Henk E D J; Shinozaki, Tsuyoshi; Zhang, Ying Ming; Zhang, Mei Luo; Wakayama, Yuji; Sugai, Yoshinao; Kagaya, Yutaka; Miura, Masahito; Boyden, Penelope A; Stuyvers, Bruno D M; Landesberg, Amir

    2008-01-01

    Starling's Law and the well-known end-systolic pressure-volume relationship (ESPVR) of the left ventricle reflect the effect of sarcomere length (SL) on stress (sigma) development and shortening by myocytes in the uniform ventricle. We show here that tetanic contractions of rat cardiac trabeculae exhibit a sigma-SL relationship at saturating [Ca2+] that depends on sarcomere geometry in a manner similar to skeletal sarcomeres and the existence of opposing forces in cardiac muscle shortened below slack length. The sigma-SL-[Ca2+]free relationships (sigma-SL-CaR) at submaximal [Ca2+] in intact and skinned trabeculae were similar, albeit that the sensitivity for Ca2+ of intact muscle was higher. We analyzed the mechanisms underlying the sigma-SL-CaR using a kinetic model where we assumed that the rates of Ca2+ binding by Troponin-C (Tn-C) and/or cross-bridge (XB) cycling are determined by SL, [Ca2+] or stress. We analyzed the correlation between the model results and steady state stress measurements at varied SL and [Ca2+] from skinned rat cardiac trabeculae to test the hypotheses that: (i) the dominant feedback mechanism is SL, stress or [Ca2+]-dependent; and (ii) the feedback mechanism regulates: Tn-C-Ca2+ affinity, XB kinetics or, unitary XB-force. The analysis strongly suggests that feedback of the number of strong XBs to cardiac Tn-C-Ca2+ affinity is the dominant mechanism that regulates XB recruitment. Application of this concept in a mathematical model of twitch-stress accurately reproduced the sigma-SL-CaR and the time course of twitch-stress as well as the time course of intracellular [Ca2+]i. Modeling of the response of the cardiac twitch to rapid stress changes using the above feedback model uniquely predicted the occurrence of [Ca2+]i transients as a result of accelerated Ca2+ dissociation from Tn-C. The above concept has important repercussions for the non-uniformly contracting heart in which arrhythmogenic Ca2+ waves arise from weakened areas in cardiac

  8. Shock-induced termination of reentrant cardiac arrhythmias: Comparing monophasic and biphasic shock protocols

    PubMed Central

    Bragard, Jean; Simic, Ana; Elorza, Jorge; Grigoriev, Roman O.; Cherry, Elizabeth M.; Gilmour, Robert F.; Otani, Niels F.; Fenton, Flavio H.

    2013-01-01

    In this article, we compare quantitatively the efficiency of three different protocols commonly used in commercial defibrillators. These are based on monophasic and both symmetric and asymmetric biphasic shocks. A numerical one–dimensional model of cardiac tissue using the bidomain formulation is used in order to test the different protocols. In particular, we performed a total of 4.8 × 106 simulations by varying shock waveform, shock energy, initial conditions, and heterogeneity in internal electrical conductivity. Whenever the shock successfully removed the reentrant dynamics in the tissue, we classified the mechanism. The analysis of the numerical data shows that biphasic shocks are significantly more efficient (by about 25%) than the corresponding monophasic ones. We determine that the increase in efficiency of the biphasic shocks can be explained by the higher proportion of newly excited tissue through the mechanism of direct activation. PMID:24387558

  9. Shock-induced termination of reentrant cardiac arrhythmias: Comparing monophasic and biphasic shock protocols

    NASA Astrophysics Data System (ADS)

    Bragard, Jean; Simic, Ana; Elorza, Jorge; Grigoriev, Roman O.; Cherry, Elizabeth M.; Gilmour, Robert F.; Otani, Niels F.; Fenton, Flavio H.

    2013-12-01

    In this article, we compare quantitatively the efficiency of three different protocols commonly used in commercial defibrillators. These are based on monophasic and both symmetric and asymmetric biphasic shocks. A numerical one-dimensional model of cardiac tissue using the bidomain formulation is used in order to test the different protocols. In particular, we performed a total of 4.8 × 106 simulations by varying shock waveform, shock energy, initial conditions, and heterogeneity in internal electrical conductivity. Whenever the shock successfully removed the reentrant dynamics in the tissue, we classified the mechanism. The analysis of the numerical data shows that biphasic shocks are significantly more efficient (by about 25%) than the corresponding monophasic ones. We determine that the increase in efficiency of the biphasic shocks can be explained by the higher proportion of newly excited tissue through the mechanism of direct activation.

  10. Shock-induced termination of reentrant cardiac arrhythmias: Comparing monophasic and biphasic shock protocols

    SciTech Connect

    Bragard, Jean Simic, Ana; Elorza, Jorge; Grigoriev, Roman O.; Fenton, Flavio H.; Cherry, Elizabeth M.; Gilmour, Robert F.; Otani, Niels F.

    2013-12-15

    In this article, we compare quantitatively the efficiency of three different protocols commonly used in commercial defibrillators. These are based on monophasic and both symmetric and asymmetric biphasic shocks. A numerical one–dimensional model of cardiac tissue using the bidomain formulation is used in order to test the different protocols. In particular, we performed a total of 4.8 × 10{sup 6} simulations by varying shock waveform, shock energy, initial conditions, and heterogeneity in internal electrical conductivity. Whenever the shock successfully removed the reentrant dynamics in the tissue, we classified the mechanism. The analysis of the numerical data shows that biphasic shocks are significantly more efficient (by about 25%) than the corresponding monophasic ones. We determine that the increase in efficiency of the biphasic shocks can be explained by the higher proportion of newly excited tissue through the mechanism of direct activation.

  11. Patient-centred care of patients with ventricular arrhythmias and risk of sudden cardiac death: What do the 2015 European Society of Cardiology guidelines add?

    PubMed

    Norekvål, Tone M; Kirchhof, Paulus; Fitzsimons, Donna

    2017-03-01

    Nurses and allied professionals are at the forefront of care delivery in patients with arrythmogenic risk and have a responsibility to deliver care that is focused on their individual needs. The 2015 European Society of Cardiology guideline on prevention of ventricular arrhythmia and sudden cardiac death heralds a step-change in patient and family focus and interdisciplinary involvement. This development reflects a recognition within the European Society of Cardiology that chronic care of patients with cardiovascular conditions can be improved by involving all stakeholders, making use of multidisciplinary interventions, and placing the patient at the centre of the care process. In this article, taskforce contributors discuss the latest evidence and highlight some of the most pertinent issues for nurses involved in patient-centred care of patients and families with ventricular arrhythmias and/or risk of sudden death.

  12. Changes in heart rate, arrhythmia frequency, and cardiac biomarker values in horses during recovery after a long-distance endurance ride.

    PubMed

    Flethøj, Mette; Kanters, Jørgen K; Haugaard, Maria M; Pedersen, Philip J; Carstensen, Helena; Balling, Johanne D; Olsen, Lisbeth H; Buhl, Rikke

    2016-05-01

    OBJECTIVE To evaluate heart rate, heart rate variability, and arrhythmia frequency as well as changes in cardiac biomarker values and their association with heart rate in horses before and after an endurance ride. DESIGN Cross-sectional study. ANIMALS 28 Arabian horses competing in a 120- or 160-km endurance ride. PROCEDURES ECG recordings were obtained from each horse before (preride) and after (recovery) an endurance ride to evaluate changes in heart rate and the SD of normal R-R intervals (SDNN) during the initial 12 hours of recovery. Frequencies of supraventricular and ventricular premature complexes before and after the ride were evaluated. Blood samples were obtained before the ride and twice during recovery. Hematologic analyses included measurement of serum cardiac troponin I concentration and creatine kinase isoenzyme MB activity. RESULTS Heart rate was significantly increased and SDNN was decreased during the recovery versus preride period. Frequency of ventricular premature complexes increased during recovery, albeit not significantly, whereas frequency of supraventricular premature complexes was not significantly different between preride and recovery periods. Serum cardiac troponin I concentration and creatine kinase isoenzyme MB activity were significantly increased in the recovery versus preride period. No associations were identified between cardiac biomarkers and velocity, distance, or mean heart rate. CONCLUSIONS AND CLINICAL RELEVANCE Heart rate increased and SDNN decreased in horses after completion of an endurance ride. These and other cardiac changes suggested that prolonged exercise such as endurance riding might have cardiac effects in horses. Additional studies are needed to clarify the clinical relevance of the findings.

  13. Wavelet formation in excitable cardiac tissue: the role of wavefront-obstacle interactions in initiating high-frequency fibrillatory-like arrhythmias.

    PubMed Central

    Starobin, J M; Zilberter, Y I; Rusnak, E M; Starmer, C F

    1996-01-01

    High-frequency arrhythmias leading to fibrillation are often associated with the presence of inhomogeneities (obstacles) in cardiac tissue and reduced excitability of cardiac cells. Studies of antiarrhythmic drugs in patients surviving myocardial infarction revealed an increased rate of sudden cardiac death compared with untreated patients. These drugs block the cardiac sodium channel, thereby reducing excitability, which may alter wavefront-obstacle interactions. In diseased atrial tissue, excitability is reduced by diminished sodium channel availability secondary to depolarized rest potentials and cellular decoupling secondary to intercellular fibrosis. Excitability can also be reduced by incomplete recovery between successive excitations. In all of these cases, wavefront-obstacle interactions in a poorly excitable medium may reflect an arrhythmogenic process that permits formation of reentrant wavelets leading to flutter, fibrillation, and sudden cardiac death. To probe the relationship between excitability and arrhythmogenesis, we explored conditions for new wavelet formation after collision of a plane wave with an obstacle in an otherwise homogeneous excitable medium. Formulating our approach in terms of the balance between charge available in the wavefront and the excitation charge requirements of adjacent medium, we found analytically the critical medium parameters that defined conditions for wavefront-obstacle separation. Under these conditions, when a parent wavefront collided with a primitive obstacle, the resultant fragments separated from the obstacle boundaries, subsequently curled, and spawned new "daughter" wavelets. We identified spatial arrangements of obstacles such that wavefront-obstacle collisions leading to spawning of new wavelets could produce high-frequency wavelet trains similar to fibrillation-like arrhythmias. Images FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 6 FIGURE 7 PMID:8789078

  14. αB-Crystallin R120G variant causes cardiac arrhythmias and alterations in the expression of Ca(2+) -handling proteins and endoplasmic reticulum stress in mice.

    PubMed

    Jiao, Qibin; Sanbe, Atsushi; Zhang, Xingwei; Liu, Jun-Ping; Minamisawa, Susumu

    2014-08-01

    Mutations of αB-crystallin (CryαB), a small heat shock protein abundantly expressed in cardiac and skeletal muscles, are known to cause desmin-related myopathies. The CryαB R120G allele has been linked to a familial desminopathy and, in transgenic mice, causes a sudden death at about 28 weeks of age. To investigate the mechanisms of the sudden cardiac arrest of CryαB R120G transgenic mice, we prepared protein samples from left ventricular tissues of two different age groups (10 and 28 weeks) and examined Ca(2+) -handling proteins. Expression of sarcoplasmic/endoplasmic reticulum calcium ATPase (SERCA) 2, phospholamban, ryanodine receptor 2 and calsequestrin 2 was significantly decreased in 28- versus 10-week-old CryαB R120G transgenic mice. In addition, low heart rate variability, including heart rate, total power and low frequency, was observed and continuous electrocardiogram monitoring revealed cardiac arrhythmias, such as ventricular tachycardia, atrioventricular block and atrial flutter, in 28-week-old CryαB R120G transgenic mice. In contrast, expression of endoplasmic reticulum (ER) degradation enhancing α-mannosidase-like protein, inositol requirement 1 and X-box binding protein 1 were increased significantly in 28- versus 10-week-old CryαBR120G transgenic mice, suggesting that the CryαBR120G transgenic mice exhibit increased ER stress compared with wild-type mice. Together, the data suggest that the CryαB R120G dominant variant induces ER stress and impairs Ca(2+) regulation, leading to ageing-related cardiac dysfunction, arrhythmias and decreased autonomic tone with shortened lifespan.

  15. Neuronal Na+ Channels Are Integral Components of Pro-arrhythmic Na+/Ca2+ Signaling Nanodomain That Promotes Cardiac Arrhythmias During β-adrenergic Stimulation

    PubMed Central

    Radwański, Przemysław B.; Ho, Hsiang-Ting; Veeraraghavan, Rengasayee; Brunello, Lucia; Liu, Bin; Belevych, Andriy E.; Unudurthi, Sathya D.; Makara, Michael A.; Priori, Silvia G.; Volpe, Pompeo; Armoundas, Antonis A.; Dillmann, Wolfgang H.; Knollmann, Bjorn C.; Mohler, Peter J.; Hund, Thomas J.; Györke, Sándor

    2016-01-01

    Background Cardiac arrhythmias are a leading cause of death in the US. Vast majority of these arrhythmias including catecholaminergic polymorphic ventricular tachycardia (CPVT) are associated with increased levels of circulating catecholamines and involve abnormal impulse formation secondary to aberrant Ca2+ and Na+ handling. However, the mechanistic link between β-AR stimulation and the subcellular/molecular arrhythmogenic trigger(s) remains elusive. Methods and Results We performed functional and structural studies to assess Ca2+ and Na+ signaling in ventricular myocyte as well as surface electrocardiograms in mouse models of cardiac calsequestrin (CASQ2)-associated CPVT. We demonstrate that a subpopulation of Na+ channels (neuronal Na+ channels; nNav) that colocalize with RyR2 and Na+/Ca2+ exchanger (NCX) are a part of the β-AR-mediated arrhythmogenic process. Specifically, augmented Na+ entry via nNav in the settings of genetic defects within the RyR2 complex and enhanced sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA)-mediated SR Ca2+ refill is both an essential and a necessary factor for the arrhythmogenesis. Furthermore, we show that augmentation of Na+ entry involves β-AR-mediated activation of CAMKII subsequently leading to nNav augmentation. Importantly, selective pharmacological inhibition as well as silencing of Nav1.6 inhibit myocyte arrhythmic potential and prevent arrhythmias in vivo. Conclusion These data suggest that the arrhythmogenic alteration in Na+/Ca2+ handling evidenced ruing β-AR stimulation results, at least in part, from enhanced Na+ influx through nNav. Therefore, selective inhibition of these channels and Nav1.6 in particular can serve as a potential antiarrhythmic therapy. PMID:27747307

  16. Catheter Ablation of Idiopathic Ventricular Arrhythmias Arising From the Cardiac Outflow Tracts - Recent Insights and Techniques for the Successful Treatment of Common and Challenging Cases.

    PubMed

    Heeger, Christian-Hendrik; Hayashi, Kentaro; Kuck, Karl-Heinz; Ouyang, Feifan

    2016-04-25

    Ventricular arrhythmias (VA), like premature ventricular contractions (PVC) and ventricular tachycardia (VT) in patients without structural heart disease (idiopathic VA), mainly arise from the right and left ventricular outflow tracts (RVOT/LVOT). The prognosis for OT VA is generally good in the majority of patients, but there is potential for developing dilated cardiomyopathies from the high burden of VA, as well as a certain risk for sudden cardiac death because of fast monomorphic VT or polymorphic VT triggered by short-coupling PVC. Radiofrequency catheter ablation (RFCA) has evolved into a widely accepted treatment strategy for patients suffering from VAs. A detailed knowledge of surface ECGs and complex cardiac anatomy, especially within the ventricular OTs, is essential for the understanding of cardiac OT-VAs and highly related to safe and successful RFCA procedures. This review article focuses on RFCA of idiopathic VA arising from the cardiac OT as well as adjacent regions and will illustrate recent insights and technical issues. (Circ J 2016; 80: 1073-1086).

  17. Biofeedback assisted control of respiratory sinus arrhythmia as a biobehavioral intervention for depressive symptoms in patients after cardiac surgery: a preliminary study.

    PubMed

    Patron, Elisabetta; Messerotti Benvenuti, Simone; Favretto, Giuseppe; Valfrè, Carlo; Bonfà, Carlotta; Gasparotto, Renata; Palomba, Daniela

    2013-03-01

    The current study investigated whether biofeedback training aimed at increasing respiratory sinus arrhythmia (RSA), a measure of cardiac vagal modulation, can reduce depressive symptoms in patients after cardiac surgery. This randomized controlled study enrolled 26 patients after first-time cardiac surgery. The patients were randomly assigned to an RSA-biofeedback group (N = 13) or to a treatment as usual group (N = 13). The biofeedback training consisted of five 45 min sessions designed to increase RSA. The outcome was assessed as changes in RSA and in the Centre for Epidemiologic Studies of Depression (CES-D) values from pre- to post-training. Both groups were comparable for demographic and biomedical characteristics. RSA increased significantly in patients who underwent RSA-biofeedback compared to controls. Moreover, the CES-D scores were reduced significantly from pre- to post-training in the RSA-biofeedback group compared to the controls. Changes in RSA were inversely related to changes in CES-D scores from pre- to post-training. These findings extend the effectiveness of RSA-biofeedback for increasing vagal modulation as well as for reducing depressive symptoms in post-surgical patients. Overall, the current study also suggests that this biobehavioral intervention may add to the efficacy of postoperative risk reduction programs and rehabilitation protocols in cardiac surgery patients.

  18. [Maternal arrhythmias during pregnancy. Practical review].

    PubMed

    Kornacewicz-Jach, Zdzisława; Peregud-Pogorzelska, Małgorzata

    2014-01-01

    Pregnancy is accompanied by a variety of cardiovascular changes in normal women, and these changes can increased incidence of maternal cardiac arrhythmias. Supraventricular and ventricular arrhythmias reguiring treatment are rarely seen during pregnancy in healthy women. Structural cardiac defects or residual defects after repair may contribute to the occurrence of clinically relevant arrhythmias. Arrhythmias during pregnancy include a wide spectrum. The most common are simple ventricular and atrial ectopy, sinusal tachycardia and supraventricular tachycardia. The foetus may suffer both haemodynamic alternations and adverse effects of the treatment (teratogenic risk, foetal growth and development). The management of arrhythmias in pregnant women is similar to that taken in patients who are not pregnant.

  19. TRPA1 and Sympathetic Activation contribute to increased risk of triggered cardiac arrhythmias in hypertensive rats exposed to diesel exhaust

    EPA Science Inventory

    Background -Diesel exhaust (DE), which is emitted from on-and off-road sources, is a complex mixture of toxic gaseous and particulate components that results in adverse cardiovascular effects. Arrhythmias, which are often triggered in the hours and days following exposure, are on...

  20. The Effect of a Novel Highly Selective Inhibitor of the Sodium/Calcium Exchanger (NCX) on Cardiac Arrhythmias in In Vitro and In Vivo Experiments

    PubMed Central

    Kohajda, Zsófia; Farkas-Morvay, Nikolett; Jost, Norbert; Nagy, Norbert; Geramipour, Amir; Horváth, András; Varga, Richárd S.; Hornyik, Tibor; Corici, Claudia; Acsai, Károly; Horváth, Balázs; Prorok, János; Ördög, Balázs; Déri, Szilvia; Tóth, Dániel; Levijoki, Jouko; Pollesello, Piero; Koskelainen, Tuula; Otsomaa, Leena; Tóth, András; Baczkó, István; Leprán, István; Nánási, Péter P.; Papp, Julius Gy; Varró, András; Virág, László

    2016-01-01

    Background In this study the effects of a new, highly selective sodium-calcium exchanger (NCX) inhibitor, ORM-10962 were investigated on cardiac NCX current, Ca2+ transients, cell shortening and in experimental arrhythmias. The level of selectivity of the novel inhibitor on several major transmembrane ion currents (L-type Ca2+ current, major repolarizing K+ currents, late Na+ current, Na+/K+ pump current) was also determined. Methods Ion currents in single dog ventricular cells (cardiac myocytes; CM), and action potentials in dog cardiac multicellular preparations were recorded utilizing the whole-cell patch clamp and standard microelectrode techniques, respectively. Ca2+ transients and cell shortening were measured in fluorescent dye loaded isolated dog myocytes. Antiarrhythmic effects of ORM-10962 were studied in anesthetized ouabain (10 μg/kg/min i.v.) pretreated guinea pigs and in ischemia-reperfusion models (I/R) of anesthetized coronary artery occluded rats and Langendorff perfused guinea pigs hearts. Results ORM-10962 significantly reduced the inward/outward NCX currents with estimated EC50 values of 55/67 nM, respectively. The compound, even at a high concentration of 1 μM, did not modify significantly the magnitude of ICaL in CMs, neither had any apparent influence on the inward rectifier, transient outward, the rapid and slow components of the delayed rectifier potassium currents, the late and peak sodium and Na+/K+ pump currents. NCX inhibition exerted moderate positive inotropic effect under normal condition, negative inotropy when reverse, and further positive inotropic effect when forward mode was facilitated. In dog Purkinje fibres 1 μM ORM-10962 decreased the amplitude of digoxin induced delayed afterdepolarizations (DADs). Pre-treatment with 0.3 mg/kg ORM-10962 (i.v.) 10 min before starting ouabain infusion significantly delayed the development and recurrence of ventricular extrasystoles (by about 50%) or ventricular tachycardia (by about 30

  1. [Arrhythmias from swallowing].

    PubMed

    Palazzuoli, V; Mondillo, S; Faglia, S; D'Aprile, N; De Luca, G; Kristodhullu, A; Corba, E

    1992-01-01

    We describe the case of a 51-year old, non cardiopathic patient, with recurrent attacks of supraventricular tachycardia induced by swallowing. In the existing literature we found several descriptions of hypokinetic arrhythmias, easily explained by a mechanism of vagal inhibition. The cases of predominantly hyperkinetic arrhythmias, however, are much less common. In these patients the origin of the disease seems to be due to sympathetic oesophageal fibers and superior and medium cardiac nerves. In the present case, as in the others reported in the literature, the drug of choice seems to be Amiodarone which appears to be the most effective in preventing tachyarrhythmias caused by swallowing.

  2. Cardioprotective activity of alcoholic extract of Tinospora cordifolia (Willd.) Miers in calcium chloride-induced cardiac arrhythmia in rats

    PubMed Central

    Sharma, Ashish Kumar; Kishore, Kunal; Sharma, Divya; Srinivasan, B.P; Agarwal, Shyam Sunder; Sharma, Ashok; Singh, Santosh Kumar; Gaur, Samir; Jatav, Vijay Singh

    2011-01-01

    The present study investigated the antiarrhythmic activity of alcoholic extract of Tinospora cordifolia (T. cordifolia) in CaCl2 induced arrhythmia. CaCl2 (25 mg/kg) was administered by intravenous infusion (iv) to produce arrhythmia in rats. The animals were then treated with T. cordifolia extract (150, 250, and 450 mg/kg) and verapamil (5 mg/kg,iv). Lead II electrocardiogram was monitored. Plasma calcium, sodium and potassium levels were measured. In CaCl2 induced arrhythmia, heart rate was decreased by 41.10%, T. cordifolia at 150, 300, and 450 mg/kg decreased the heart rate by 26.30%, 29.16%, and 38.29%, respectively, and verapamil reduced the heart rate by 9.70% compared to the normal group. The PQRST waves were normalized and atrial and ventricular fibrillation was controlled in rats treated with verapamil and T. cordifolia. CaCl2 increased calcium and sodium levels and decreased potassium levels in blood. T. cordifolia dose-dependently decreased calcium and sodium levels and increased potassium levels. Hence, T. cordifolia can be used in antiarrhythmic clinical settings and beneficial in atrial and ventricular fibrillation and flutter and may be indicated in ventricular tachyarrhythmia. PMID:23554702

  3. Sudden Cardiac Arrest

    MedlinePlus

    ... from American Heart Association Aneurysms and Dissections Angina Arrhythmia Bundle Branch Block Cardiomyopathy Carotid Artery Disease Chronic ... terms: SCA, sudden cardiac death (SCD), sudden death, arrhythmias, ... ventricular fibrillation, defibrillator, automatic cardiac defibrillator ( ...

  4. Genetics of inherited primary arrhythmia disorders

    PubMed Central

    Spears, Danna A; Gollob, Michael H

    2015-01-01

    A sudden unexplained death is felt to be due to a primary arrhythmic disorder when no structural heart disease is found on autopsy, and there is no preceding documentation of heart disease. In these cases, death is presumed to be secondary to a lethal and potentially heritable abnormality of cardiac ion channel function. These channelopathies include congenital long QT syndrome, catecholaminergic polymorphic ventricular tachycardia, Brugada syndrome, and short QT syndrome. In certain cases, genetic testing may have an important role in supporting a diagnosis of a primary arrhythmia disorder, and can also provide prognostic information, but by far the greatest strength of genetic testing lies in the screening of family members, who may be at risk. The purpose of this review is to describe the basic genetic and molecular pathophysiology of the primary inherited arrhythmia disorders, and to outline a rational approach to genetic testing, management, and family screening. PMID:26425105

  5. Dual optical recordings for action potentials and calcium handling in induced pluripotent stem cell models of cardiac arrhythmias using genetically encoded fluorescent indicators.

    PubMed

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

    2015-05-01

    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.

  6. Teaching cardiac electrophysiology modeling to undergraduate students: laboratory exercises and GPU programming for the study of arrhythmias and spiral wave dynamics.

    PubMed

    Bartocci, Ezio; Singh, Rupinder; von Stein, Frederick B; Amedome, Avessie; Caceres, Alan Joseph J; Castillo, Juan; Closser, Evan; Deards, Gabriel; Goltsev, Andriy; Ines, Roumwelle Sta; Isbilir, Cem; Marc, Joan K; Moore, Diquan; Pardi, Dana; Sadhu, Sandeep; Sanchez, Samuel; Sharma, Pooja; Singh, Anoopa; Rogers, Joshua; Wolinetz, Aron; Grosso-Applewhite, Terri; Zhao, Kai; Filipski, Andrew B; Gilmour, Robert F; Grosu, Radu; Glimm, James; Smolka, Scott A; Cherry, Elizabeth M; Clarke, Edmund M; Griffeth, Nancy; Fenton, Flavio H

    2011-12-01

    As part of a 3-wk intersession workshop funded by a National Science Foundation Expeditions in Computing award, 15 undergraduate students from the City University of New York(1) collaborated on a study aimed at characterizing the voltage dynamics and arrhythmogenic behavior of cardiac cells for a broad range of physiologically relevant conditions using an in silico model. The primary goal of the workshop was to cultivate student interest in computational modeling and analysis of complex systems by introducing them through lectures and laboratory activities to current research in cardiac modeling and by engaging them in a hands-on research experience. The success of the workshop lay in the exposure of the students to active researchers and experts in their fields, the use of hands-on activities to communicate important concepts, active engagement of the students in research, and explanations of the significance of results as the students generated them. The workshop content addressed how spiral waves of electrical activity are initiated in the heart and how different parameter values affect the dynamics of these reentrant waves. Spiral waves are clinically associated with tachycardia, when the waves remain stable, and with fibrillation, when the waves exhibit breakup. All in silico experiments were conducted by simulating a mathematical model of cardiac cells on graphics processing units instead of the standard central processing units of desktop computers. This approach decreased the run time for each simulation to almost real time, thereby allowing the students to quickly analyze and characterize the simulated arrhythmias. Results from these simulations, as well as some of the background and methodology taught during the workshop, is presented in this article along with the programming code and the explanations of simulation results in an effort to allow other teachers and students to perform their own demonstrations, simulations, and studies.

  7. Cardiac arrhythmia and late-onset muscle weakness caused by a myofibrillar myopathy with unusual histopathological features due to a novel missense mutation in FLNC.

    PubMed

    Avila-Smirnow, D; Gueneau, L; Batonnet-Pichon, S; Delort, F; Bécane, H-M; Claeys, K; Beuvin, M; Goudeau, B; Jais, J-P; Nelson, I; Richard, P; Ben Yaou, R; Romero, N B; Wahbi, K; Mathis, S; Voit, T; Furst, D; van der Ven, P; Gil, R; Vicart, P; Fardeau, M; Bonne, G; Behin, A

    2016-10-01

    Myofibrillar myopathies (MFM) are mostly adult-onset diseases characterized by progressive morphological alterations of the muscle fibers beginning in the Z-disk and the presence of protein aggregates in the sarcoplasm. They are mostly caused by mutations in different genes that encode Z-disk proteins, including DES, CRYAB, LDB3, MYOT, FLNC and BAG3. A large family of French origin, presenting an autosomal dominant pattern, characterized by cardiac arrhythmia associated to late-onset muscle weakness, was evaluated to clarify clinical, morphological and genetic diagnosis. Muscle weakness began during adult life (over 30 years of age), and had a proximal distribution. Histology showed clear signs of a myofibrillar myopathy, but with unusual, large inclusions. Subsequently, genetic testing was performed in MFM genes available for screening at the time of clinical/histological diagnosis, and desmin (DES), αB-crystallin (CRYAB), myotilin (MYOT) and ZASP (LDB3), were excluded. LMNA gene screening found the p.R296C variant which did not co-segregate with the disease. Genome wide scan revealed linkage to 7q.32, containing the FLNC gene. FLNC direct sequencing revealed a heterozygous c.3646T>A p.Tyr1216Asn change, co-segregating with the disease, in a highly conserved amino acid of the protein. Normal filamin C levels were detected by Western-blot analysis in patient muscle biopsies and expression of the mutant protein in NIH3T3 showed filamin C aggregates. This is an original FLNC mutation in a MFM family with an atypical clinical and histopathological presentation, given the presence of significantly focal lesions and prominent sarcoplasmic masses in muscle biopsies and the constant heart involvement preceding significantly the onset of the myopathy. Though a rare etiology, FLNC gene should not be excluded in early-onset arrhythmia, even in the absence of myopathy, which occurs later in the disease course.

  8. Exercise and Inherited Arrhythmias.

    PubMed

    Cheung, Christopher C; Laksman, Zachary W M; Mellor, Gregory; Sanatani, Shubhayan; Krahn, Andrew D

    2016-04-01

    Sudden cardiac death (SCD) in an apparently healthy individual is a tragedy that prompts a series of investigations to identify the cause of death and to prevent SCD in potentially at-risk family members. Several inherited channelopathies and cardiomyopathies, including long QT syndrome (LQTS), catecholaminergic polymorphic ventricular cardiomyopathy (CPVT), hypertrophic cardiomyopathy (HCM), and arrhythmogenic right ventricular cardiomyopathy (ARVC) are associated with exercise-related SCD. Exercise restriction has been a historical mainstay of therapy for these conditions. Syncope and cardiac arrest occur during exercise in LQTS and CPVT because of ventricular arrhythmias, which are managed with β-blockade and exercise restriction. Exercise may provoke hemodynamic or ischemic changes in HCM, leading to ventricular arrhythmias. ARVC is a disease of the desmosome, whose underlying disease process is accelerated by exercise. On this basis, expert consensus has erred on the side of caution, recommending rigorous exercise restriction for all inherited arrhythmias. With time, as familiarity with inherited arrhythmia conditions has increased and patients with milder forms of disease are diagnosed, practitioners have questioned the historical rigorous restrictions advocated for all. This change has been driven by the fact that these are often children and young adults who wish to lead active lives. Recent evidence suggests a lower risk of exercise-related arrhythmias in treated patients than was previously assumed, including those with previous symptoms managed with an implantable cardioverter-defibrillator. In this review, we emphasize shared decision making, monitored medical therapy, individual and team awareness of precautions and emergency response measures, and a more permissive approach to recreational and competitive exercise.

  9. Executive Summary: European Heart Rhythm Association Consensus Document on the Management of Supraventricular Arrhythmias: Endorsed by Heart Rhythm Society (HRS), Asia-Pacific Heart Rhythm Society (APHRS), and Sociedad Latinoamericana de Estimulación Cardiaca y Electrofisiologia (SOLAECE).

    PubMed

    Katritsis, Demosthenes G; Boriani, Giuseppe; Cosio, Francisco G; Jais, Pierre; Hindricks, Gerhard; Josephson, Mark E; Keegan, Roberto; Knight, Bradley P; Kuck, Karl-Heinz; Lane, Deirdre A; Lip, Gregory Yh; Malmborg, Helena; Oral, Hakan; Pappone, Carlo; Themistoclakis, Sakis; Wood, Kathryn A; Young-Hoon, Kim; Lundqvist, Carina Blomström

    2016-01-01

    This paper is an executive summary of the full European Heart Rhythm Association (EHRA) consensus document on the management of supraventricular arrhythmias, published in Europace. It summarises developments in the field and provides recommendations for patient management, with particular emphasis on new advances since the previous European Society of Cardiology guidelines. The EHRA consensus document is available to read in full at http://europace.oxfordjournals.org.

  10. SU-C-303-06: Treatment Planning Study for Non-Invasive Cardiac Arrhythmia Ablation with Scanned Carbon Ions in An Animal Model

    SciTech Connect

    Eichhorn, A; Constantinescu, A; Prall, M; Kaderka, R; Durante, M; Graeff, C; Lehmann, H I; Takami, M; Packer, D L; Lugenbiel, P; Thomas, D; Richter, D; Bert, C

    2015-06-15

    Purpose: Scanned carbon ion beams might offer a non-invasive alternative treatment for cardiac arrhythmia, which are a major health-burden. We studied the feasibility of this procedure in an animal model. The underlying treatment planning and motion mitigation strategies will be presented. Methods: The study was carried out in 15 pigs, randomly distributed to 3 target groups: atrioventricular node (AVN, 8 animals with 25, 40, and 55 Gy target dose), left ventricular free-wall (LV, 4 animals with 40 Gy) and superior pulmonary vein (SPV, 3 animals with 40 Gy). Breathing motion was suppressed by repeated enforced breathholds at end exhale. Cardiac motion was mitigated by an inhomogeneous rescanning scheme with up to 15 rescans. The treatment planning was performed using the GSI in-house software TRiP4D on cardiac-gated 4DCTs, applying a range-considering ITV based on an extended CTV. For AVN and SPV isotropic 5 mm margins were applied to the CTV, while for the LV 2mm+2% range margins were used. The opposing fields for AVN and LV targets were optimized independently (SFUD), while SPV treatments were optimized as IMPT deliveries, including dose restrictions to the radiosensitive AVN. Results: Median value of D{sub 95} over all rescanning simulations was 99.1% (AVN), 98.0% (SPV) and 98.3% (LV) for the CTV and 94.7% (AVN) and 92.7% (SPV) for the PTV, respectively. The median D{sub 5}-D{sub 95} was improved with rescanning compared to unmitigated delivery from 13.3 to 6.5% (CTV) and from 23.4 to 11.6% (PTV). ICRP dose limits for aorta, trachea, esophagus and skin were respected. The maximal dose in the coronary arteries was limited to 30 Gy. Conclusion: We demonstrated the feasibility of a homogeneous dose delivery to different cardiac structures in a porcine model using a time-optimized inhomogeneous rescanning scheme. The presented treatment planning strategies were applied in a pig study with the analysis ongoing. Funding: This work was supported in part by the

  11. The role of cromakalim and a nitric oxide synthase blocker in cardiac arrhythmia in the intact baboon model.

    PubMed

    Hay, L; Schutte, P J; Du Plooy, W J; Kahler, C P

    2000-02-01

    The arrhythmogenic effect of adenosine triphosphate (ATP)-sensitive potassium channel openers is controversial and may be dependent on the type of animal model used. Information on the effect of these drugs in the normal primate model is limited. The purpose of this study was first to determine the arrhythmogenic properties of cromakalim in the baboon and second to determine whether N-omega-nitro-L-arginine methyl ester (L-NAME) has any effect on the induced arrhythmia. Adult (2-4 years old) baboons (Papio ursinus) were anesthetized with a continuous i.v. infusion of ketamine (100 mg/ ml), diazepam (5 mg/ml), and saline (ratio 2:2:50) at a rate of 40-60 ml/h. Sympathetic responses were inhibited by administration of propranolol (1 mg/kg) before the start of the experiments. Cromakalim (30 microg/kg) was administered before and after L-NAME (7.5 mg/kg), and the parameters were monitored for 15 min after each intervention. A Millar double-tipped microcatheter was used to record left ventricular and aortic pressures. Lead II of the ECG was monitored. During a 15-min period after administration of cromakalim, 22.3 +/- 6.0 abnormal ventricular complexes were recorded. L-NAME administration significantly reduced these abnormal complexes to 4.5 +/- 2 (paired t test, p < or = 0.05). We therefore conclude that cromakalim has arrhythmogenic properties in the baboon and that these can be attenuated by L-NAME.

  12. Weather-induced ischemia and arrhythmia in patients undergoing cardiac rehabilitation: another difference between men and women

    NASA Astrophysics Data System (ADS)

    Schneider, Alexandra; Schuh, Angela; Maetzel, Friedrich-Karl; Rückerl, Regina; Breitner, Susanne; Peters, Annette

    2008-07-01

    Given the accumulating evidence that people with underlying heart disease are a particularly vulnerable group for triggers like changing meteorological parameters, the objective of this longitudinal study was to analyze the influence of weather parameters on blood pressure, arrhythmia and ischemia in cardiovascular patients. A panel study with repeated measurements was conducted in a rehabilitation clinic in Timmendorfer Strand (Baltic Sea, Germany) with 872 cardiovascular patients. Heart rate, blood pressure and electrocardiography changes were measured during repeated bicycle ergometries. Generalized Estimating Equations were used for regression analyses of immediate, delayed and cumulative influences of the daily measured meteorological data. For men, a decrease in air temperature and in water vapor pressure doubled the risk of ST-segment depression during ergometry [odds ratio (OR) for 1 day delay: 1.88 (1.24; 2.83) for air temperature] with a delay of 1-2 days. For women, an increase of their heart rate before the start of the ergometry [same day: 4.36 beats/min (0.99; 7.74) for air temperature] and a 2- to 3-fold higher risk for ventricular ectopic beats [1 day delay: OR 2.43 (1.17; 5.05) for air temperature] was observed with an increase in temperature and water vapor pressure in almost all analyzed time-windows. The study indicates that meteorological parameters can induce changes in heart function which may lead to adverse cardiovascular events especially in susceptible, diseased individuals. The observed effect on ST-segment depression could be a link between the association of weather changes and cardiovascular morbidity and mortality.

  13. Treating Arrhythmias in Children

    MedlinePlus

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More Treating Arrhythmias in Children Updated:Dec 21,2016 Many options ... card This content was last reviewed September 2016. Arrhythmia • Home • About Arrhythmia • Why Arrhythmia Matters • Understand Your ...

  14. Medications for Arrhythmia

    MedlinePlus

    ... Disease Venous Thromboembolism Aortic Aneurysm More Medications for Arrhythmia Updated:Dec 21,2016 When taken exactly as ... health. This content was last reviewed September 2016. Arrhythmia • Home • About Arrhythmia • Why Arrhythmia Matters • Understand Your ...

  15. Why Arrhythmia Matters

    MedlinePlus

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More Why Arrhythmia Matters Updated:Dec 21,2016 When the heart's ... fibrillation. This content was last reviewed September 2016. Arrhythmia • Home • About Arrhythmia • Why Arrhythmia Matters • Understand Your ...

  16. Types of Arrhythmia

    MedlinePlus

    ... page from the NHLBI on Twitter. Types of Arrhythmia The four main types of arrhythmia are premature ( ... exercise, or too much caffeine or nicotine. Supraventricular Arrhythmias Supraventricular arrhythmias are tachycardias (fast heart rates) that ...

  17. Common Tests for Arrhythmia

    MedlinePlus

    ... Venous Thromboembolism Aortic Aneurysm More Common Tests for Arrhythmia Updated:Dec 21,2016 Several tests can help ... View an animation of arrhythmia . Common Tests for Arrhythmia Holter monitor (continuous ambulatory electrocardiographic monitor) Suspected arrhythmias ...

  18. Children and Arrhythmia

    MedlinePlus

    ... Disease Venous Thromboembolism Aortic Aneurysm More Children and Arrhythmia Updated:Dec 21,2016 If your child has ... options This content was last reviewed September 2016. Arrhythmia • Home • About Arrhythmia • Why Arrhythmia Matters • Understand Your ...

  19. Toll-like receptor 4 activation promotes cardiac arrhythmias by decreasing the transient outward potassium current (Ito) through an IRF3-dependent and MyD88-independent pathway.

    PubMed

    Monnerat-Cahli, Gustavo; Alonso, Hiart; Gallego, Monica; Alarcón, Micaela Lopez; Bassani, Rosana A; Casis, Oscar; Medei, Emiliano

    2014-11-01

    Cardiac arrhythmias are one of the main causes of death worldwide. Several studies have shown that inflammation plays a key role in different cardiac diseases and Toll-like receptors (TLRs) seem to be involved in cardiac complications. In the present study, we investigated whether the activation of TLR4 induces cardiac electrical remodeling and arrhythmias, and the signaling pathway involved in these effects. Membrane potential was recorded in Wistar rat ventricle. Ca(2+) transients, as well as the L-type Ca(2+) current (ICaL) and the transient outward K(+) current (Ito), were recorded in isolated myocytes after 24 h exposure to the TLR4 agonist, lipopolysaccharide (LPS, 1 μg/ml). TLR4 stimulation in vitro promoted a cardiac electrical remodeling that leads to action potential prolongation associated with arrhythmic events, such as delayed afterdepolarization and triggered activity. After 24 h LPS incubation, Ito amplitude, as well as Kv4.3 and KChIP2 mRNA levels were reduced. The Ito decrease by LPS was prevented by inhibition of interferon regulatory factor 3 (IRF3), but not by inhibition of interleukin-1 receptor-associated kinase 4 (IRAK4) or nuclear factor kappa B (NF-κB). Extrasystolic activity was present in 25% of the cells, but apart from that, Ca(2+) transients and ICaL were not affected by LPS; however, Na(+)/Ca(2+) exchanger (NCX) activity was apparently increased. We conclude that TLR4 activation decreased Ito, which increased AP duration via a MyD88-independent, IRF3-dependent pathway. The longer action potential, associated with enhanced Ca(2+) efflux via NCX, could explain the presence of arrhythmias in the LPS group.

  20. Biobehavioral Triggers of Cardiac Arrhythmia during Daily Life: The Role of Emotion, Physical Activity, and Heart Rate Variability

    DTIC Science & Technology

    2004-01-01

    23% up to 18 months following infarct (e.g., Frasure-Smith, Lesperance & Talajic, 1995; Bush, Ziegelstein, Tayback, Richter, Stevens , et al., 2001...has been documented in response to acute anxiety in other studies (e.g., Johnson, Thayer, Laberg , Wormnes, Raadal, et al., 2033), but trait anxiety...Richter, Stevens , et al., 2001). In future studies, it may be prudent to examine patients who are less than two years post-infarct and have recently

  1. Recurrent Muscle Weakness with Rhabdomyolysis, Metabolic Crises, and Cardiac Arrhythmia Due to Bi-allelic TANGO2 Mutations

    PubMed Central

    Lalani, Seema R.; Liu, Pengfei; Rosenfeld, Jill A.; Watkin, Levi B.; Chiang, Theodore; Leduc, Magalie S.; Zhu, Wenmiao; Ding, Yan; Pan, Shujuan; Vetrini, Francesco; Miyake, Christina Y.; Shinawi, Marwan; Gambin, Tomasz; Eldomery, Mohammad K.; Akdemir, Zeynep Hande Coban; Emrick, Lisa; Wilnai, Yael; Schelley, Susan; Koenig, Mary Kay; Memon, Nada; Farach, Laura S.; Coe, Bradley P.; Azamian, Mahshid; Hernandez, Patricia; Zapata, Gladys; Jhangiani, Shalini N.; Muzny, Donna M.; Lotze, Timothy; Clark, Gary; Wilfong, Angus; Northrup, Hope; Adesina, Adekunle; Bacino, Carlos A.; Scaglia, Fernando; Bonnen, Penelope E.; Crosson, Jane; Duis, Jessica; Maegawa, Gustavo H.B.; Coman, David; Inwood, Anita; McGill, Jim; Boerwinkle, Eric; Graham, Brett; Beaudet, Art; Eng, Christine M.; Hanchard, Neil A.; Xia, Fan; Orange, Jordan S.; Gibbs, Richard A.; Lupski, James R.; Yang, Yaping

    2016-01-01

    The underlying genetic etiology of rhabdomyolysis remains elusive in a significant fraction of individuals presenting with recurrent metabolic crises and muscle weakness. Using exome sequencing, we identified bi-allelic mutations in TANGO2 encoding transport and Golgi organization 2 homolog (Drosophila) in 12 subjects with episodic rhabdomyolysis, hypoglycemia, hyperammonemia, and susceptibility to life-threatening cardiac tachyarrhythmias. A recurrent homozygous c.460G>A (p.Gly154Arg) mutation was found in four unrelated individuals of Hispanic/Latino origin, and a homozygous ∼34 kb deletion affecting exons 3–9 was observed in two families of European ancestry. One individual of mixed Hispanic/European descent was found to be compound heterozygous for c.460G>A (p.Gly154Arg) and the deletion of exons 3–9. Additionally, a homozygous exons 4–6 deletion was identified in a consanguineous Middle Eastern Arab family. No homozygotes have been reported for these changes in control databases. Fibroblasts derived from a subject with the recurrent c.460G>A (p.Gly154Arg) mutation showed evidence of increased endoplasmic reticulum stress and a reduction in Golgi volume density in comparison to control. Our results show that the c.460G>A (p.Gly154Arg) mutation and the exons 3–9 heterozygous deletion in TANGO2 are recurrent pathogenic alleles present in the Latino/Hispanic and European populations, respectively, causing considerable morbidity in the homozygotes in these populations. PMID:26805781

  2. Effect of SkM1 Sodium Channels Delivered Via a Cell Platform on Cardiac Conduction and Arrhythmia Induction

    PubMed Central

    Boink, Gerard J.J.; Lu, Jia; Driessen, Helen E.; Duan, Lian; Sosunov, Eugene A.; Anyukhovsky, Evgeny P.; Shlapakova, Iryna N.; Lau, David H.; Rosen, Tove S.; Danilo, Peter; Jia, Zhiheng; Ozgen, Nazira; Bobkov, Yevgeniy; Guo, Yuanjian; Brink, Peter R.; Kryukova, Yelena; Robinson, Richard B.; Entcheva, Emilia; Cohen, Ira S.; Rosen, Michael R.

    2012-01-01

    Background In depolarized myocardial infarct epicardial border zones (EBZ), the cardiac sodium channel is largely inactivated, contributing to slow conduction and reentry. We have demonstrated that adenoviral delivery of the skeletal muscle sodium channel SkM1 to EBZ normalizes conduction and reduces induction of ventricular tachycardia/fibrillation (VT/VF). We now studied the impact of canine mesenchymal stem cells (cMSC) in delivering SkM1. Methods and Results cMSC were isolated and transfected with SkM1. Co-culture experiments showed cMSC/SkM1, but not cMSC alone, maintained fast conduction at depolarized potentials. We studied 3 groups in the canine 7d infarct: sham, cMSC and cMSC/SkM1. In vivo EBZ electrograms were broad and fragmentedin sham, narrower in cMSC and narrow and unfragmented in cMSC/SkM1 (P<0.05). During programmed electrical stimulation (PES) of EBZ, QRS duration in cMSC/SkM1 was shorter than in cMSC and sham (P<0.05). PES-induced VT/VFwas equivalent in all groups (P>0.05). Conclusions cMSC provide efficient, effective delivery of SkM1 current. The interventions performed (cMSC or cMSC/SkM1) were neither antiarrhythmic nor proarrhythmic. Comparing outcomes with cMSC/SkM1 and viral gene delivery highlights the criticality of the delivery platform to SkM1 antiarrhythmic efficacy. PMID:22722661

  3. Antipsychotic Drugs and the Risk of Ventricular Arrhythmia and/or Sudden Cardiac Death: A Nation‐wide Case‐Crossover Study

    PubMed Central

    Wu, Chi‐Shin; Tsai, Yu‐Ting; Tsai, Hui‐Ju

    2015-01-01

    Background Antipsychotics have been linked to prolongation of the QT interval. However, little is known about the risk of ventricular arrhythmia (VA) and/or sudden cardiac death (SCD) associated with individual antipsychotic drug use. This study was designed to investigate the association between specific antipsychotic drugs and the risk of VA and/or SCD. Methods and Results We conducted a case‐crossover study using a nation‐wide population‐based sample obtained from Taiwan's National Health Insurance Research Database. A total of 17 718 patients with incident VA and/or SCD were enrolled. Conditional logistic regression models were applied to examine the effects of antipsychotic drug use on the risk of VA/SCD during various case and control time windows of 7, 14, and 28 days. The effect of the potency of a human ether‐à‐go‐go‐related gene (hERG) potassium channel blockade was also assessed. Antipsychotic drug use was associated with a 1.53‐fold increased risk of VA and/or SCD. Antipsychotic drugs with increased risk included clothiapine, haloperidol, prochlorperazine, thioridazine, olanzapine, quetiapine, risperidone, and sulpiride. The association was significantly higher among those with short‐term use. Antipsychotics with a high potency of the hERG potassium channel blockade had the highest risk of VA and/or SCD. Conclusion Use of antipsychotic drugs is associated with an increased risk of VA and/or SCD. Careful evaluations of the risks and benefits of antipsychotic treatment are highly recommended. PMID:25713294

  4. Arrhythmias Following Comprehensive Stage II Surgical Palliation in Single Ventricle Patients.

    PubMed

    Wilhelm, Carolyn M; Paulus, Diane; Cua, Clifford L; Kertesz, Naomi J; Cheatham, John P; Galantowicz, Mark; Fernandez, Richard P

    2016-03-01

    Post-operative arrhythmias are common in pediatric patients following cardiac surgery. Following hybrid palliation in single ventricle patients, a comprehensive stage II palliation is performed. The incidence of arrhythmias in patients following comprehensive stage II palliation is unknown. The purpose of this study is to determine the incidence of arrhythmias following comprehensive stage II palliation. A single-center retrospective chart review was performed on all single ventricle patients undergoing a comprehensive stage II palliation from January 2010 to May 2014. Pre-operative, operative, and post-operative data were collected. A clinically significant arrhythmia was defined as an arrhythmia which led to cardiopulmonary resuscitation or required treatment with either pacing or antiarrhythmic medication. Statistical analysis was performed with Wilcoxon rank-sum test and Fisher's exact test with p < 0.05 significant. Forty-eight single ventricle patients were reviewed (32 hypoplastic left heart syndrome, 16 other single ventricle variants). Age at surgery was 185 ± 56 days. Cardiopulmonary bypass time was 259 ± 45 min. Average vasoactive-inotropic score was 5.97 ± 7.58. Six patients (12.5 %) had clinically significant arrhythmias: four sinus bradycardia, one 2:1 atrioventricular block, and one slow junctional rhythm. No tachyarrhythmias were documented for this patient population. Presence of arrhythmia was associated with elevated lactate (p = 0.04) and cardiac arrest (p = 0.002). Following comprehensive stage II palliation, single ventricle patients are at low risk for development of tachyarrhythmias. The most frequent arrhythmia seen in these patients was sinus bradycardia associated with respiratory compromise.

  5. Maternal arrhythmia and perinatal outcomes

    PubMed Central

    Henry, Dana; Gonzalez, Juan M; Harris, Ian, S.; Sparks, Teresa; Killion, Molly; Thiet, Mari-Paule; Bianco, Katherine

    2016-01-01

    Objective To determine if arrhythmia in the setting of maternal cardiac disease (MCD) affects perinatal outcomes. Study Design This is a retrospective cohort study of pregnant women with MCD who delivered from 2008 to 2013. Perinatal outcomes among women with an arrhythmia were compared to those without. Result Among 143 women; 36 (25%) had an arrhythmia. Those with an arrhythmia were more likely to have a spontaneous vaginal delivery (64% vs. 43%, p < 0.05) and required fewer operative vaginal births (8% vs. 27%, p=0.02). Pregnancies were more likely to be complicated by IUGR (17% vs. 5%, p < 0.05) although there were no differences in the rate of small for gestational age. The risk of IUGR remained increased after controlling for confounding (aOR 6.98, 95% CI 1.59–30.79, p=0.01). Two cases of placental abruption were identified among mothers with arrhythmia while none were identified in the controls (p < 0.05) Conclusion Patients with arrhythmias were more likely to have a spontaneous vaginal delivery. Our data suggests that these pregnancies were an increased risk for IUGR. PMID:27309629

  6. Non-Invasive Assessment of Susceptibility to Ventricular Arrhythmias During Simulated Microgravity

    NASA Technical Reports Server (NTRS)

    Cohen, Richard J.

    1999-01-01

    The Cardiovascular Alterations Team is currently conducting studies to determine what alterations in hemodynamic regulation result from sixteen days of simulated microgravity exposure in normal human subjects. In this project we make additional measurements on these same study subjects in order to determine whether there is an increase in susceptibility to ventricular arrhythmias resulting from simulated microgravity exposure. Numerous anecdotal and documented reports from the past 30 years suggest that the incidence of ventricular arrhythmias among astronauts is increased during space flight. For example, documented runs of ventricular tachycardia have been recorded from crew members of Skylab and Mir, there was much attention given by the lay press to Mir Commander Vasily Tslbliyev's complaints of heart rhythm irregularities in July of 1997, and cardiovascular mechanisms may have been causal in the recent death of an experimental primate shortly after return from space. In 1986, a Mir cosmonaut, Alexander Laveikin, was brought home and replaced with an alternate cosmonaut as a result of cardiac dysrhythmias that began during extravehicular activity. Furthermore, at a joint NASA/NSBRI workshop held in January 1998, cardiac arrhythmias were identified as the highest priority cardiovascular risk to a human Mars mission. Despite the evidence for the risk of a potentially lethal arrhythmia resulting from microgravity exposure, the effects of space flight and the associated physiologic stresses on cardiac conduction processes are not known, and an increase in cardiac susceptibility to arrhythmias has never been quantified. In this project, we are determining whether simulated space flight increases the risk of developing life-threatening heart rhythm disturbances such as sustained ventricular tachycardia (defined as ventricular tachycardia lasting at least 30 seconds or resulting in hemodynamic collapse) and ventricular fibrillation. We are obtaining measures of

  7. How Are Arrhythmias Diagnosed?

    MedlinePlus

    ... page from the NHLBI on Twitter. How Are Arrhythmias Diagnosed? Arrhythmias can be hard to diagnose, especially the types ... symptoms every once in a while. Doctors diagnose arrhythmias based on medical and family histories, a physical ...

  8. How Are Arrhythmias Treated?

    MedlinePlus

    ... page from the NHLBI on Twitter. How Are Arrhythmias Treated? Common arrhythmia treatments include medicines, medical procedures, and surgery. Your doctor may recommend treatment if your arrhythmia causes serious symptoms, such as dizziness, chest pain, ...

  9. Devices for Arrhythmia

    MedlinePlus

    ... Disease Venous Thromboembolism Aortic Aneurysm More Devices for Arrhythmia Updated:Dec 21,2016 In a medical emergency, ... This content was last reviewed September 2016. Printable Arrhythmia Information Sheets What is Arrhythmia? What is Atrial ...

  10. Arrhythmias (For Parents)

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old Arrhythmias KidsHealth > For Parents > Arrhythmias Print A A A ... evaluated and treated by a doctor. What Causes Arrhythmias? A unique electrical conduction system in the heart ...

  11. Living with an Arrhythmia

    MedlinePlus

    ... from the NHLBI on Twitter. Living With an Arrhythmia Many arrhythmias are harmless. It's common to have an occasional ... heartbeat or mild palpitations . People who have harmless arrhythmias can live healthy lives. They usually don't ...

  12. CDP-choline prevents cardiac arrhythmias and lethality induced by short-term myocardial ischemia-reperfusion injury in the rat: involvement of central muscarinic cholinergic mechanisms.

    PubMed

    Yilmaz, M Sertac; Coskun, Cenk; Yalcin, Murat; Savci, Vahide

    2008-09-01

    induced by CDP-choline. Neither of these pretreatments except mecamylamine affected the pressor effect of CDP-choline. Intracerebroventricular mecamylamine attenuated the increase in blood pressure induced by CDP-choline. In conclusion, intravenously injected CDP-choline prevents cardiac arrhythmias and death induced by short-term myocardial ischemia-reperfusion injury. Activation of central muscarinic receptors and vagal pathways mediates the protective effect of CDP-choline. The protective effect of CDP-choline is not related to its pressor effect.

  13. Curvature Analysis of Cardiac Excitation Wavefronts

    DTIC Science & Technology

    2013-04-01

    computational cardiac-cell network accurately reproduces a particular kind of cardiac arrhythmia , such as ventricular fibrillation. Curvature Analysis of Cardiac...network accurately reproduces a particular kind of cardiac arrhythmia , such as ventricular fibrillation. Index Terms Cardiac excitation waves...isopotentials, Bézier curves, curvature, cardiac arrhythmia and fibrillation Ç 1 INTRODUCTION AN estimated 81,000,000 American adults, more than onein three

  14. Diagnosis and management of common fetal arrhythmias

    PubMed Central

    Weber, Roland; Stambach, Dominik; Jaeggi, Edgar

    2011-01-01

    Fetal arrhythmias are detected in at least 2% of unselected pregnancies during routine obstetrical scans. Most common are transient, brief episodes of a slow or fast heart rate or of an irregular heart rhythm. Less common are prolonged or persistent abnormalities such as supraventricular tachycardia and complete heart block which may lead to low cardiac output, fetal hydrops and demise. The objectives of this review are to update the reader on the diagnosis and management of the more common arrhythmias. PMID:23960639

  15. Spectrum of Fascicular Arrhythmias.

    PubMed

    Sung, Raphael; Scheinman, Melvin

    2016-09-01

    Fascicular arrhythmias encompass a wide spectrum of ventricular arrhythmias that depend on the specialized conduction system of the right and left ventricles. These arrhythmias include premature ventricular complexes, monomorphic ventricular tachycardia, polymorphic ventricular tachycardia, and ventricular fibrillation. These arrhythmias may be organized by mechanism, including intrafascicular reentry, interfascicular reentry, and focal. Mapping and ablation of the fascicular system can result in high cure rates of debilitating and potentially life-threatening arrhythmias. When approaching these arrhythmias, careful consideration of the structure of the His Purkinje system as well as their electrophysiologic properties may help guide even the most complex of arrhythmias.

  16. A troubled beginning: evolving concepts of an old arrhythmia.

    PubMed

    Hanon, Sam; Shapiro, Michael; Schweitzer, Paul

    2005-07-01

    The development of the sphygmograph in the nineteenth century marked the beginning of graphic registration of the arterial and venous pulse. Mackenzie, among other investigators, used this technique to study cardiac rhythm. In the early 20th century, Einthoven developed the electrocardiogram, which replaced the less sophisticated arterial and venous registrations of cardiac events and allowed for more detailed arrhythmia analysis. Interestingly, the early study of cardiac arrhythmias was obscured by misinterpretation. Specifically, atrial fibrillation stands out as a rhythm that was extensively studied though misconstrued in its early history. What follows is an in-depth consideration of the original investigations and evolving theories of this important arrhythmia.

  17. Effects of the myocardial-selective alpha 1-adrenoceptor antagonist UK-52046 and atenolol, alone and in combination, on experimental cardiac arrhythmias in dogs.

    PubMed Central

    Uprichard, A. G.; Harron, D. W.; Wilson, R.; Shanks, R. G.

    1988-01-01

    1. Adrenaline-induced arrhythmias in anaesthetized dogs respired with halothane were attenuated in 3 groups of 6 dogs by either UK-52046, 3.8 +/- 1.4 micrograms kg-1 (mean +/- s.e.mean), atenolol 14.6 +/- 2.1 micrograms kg-1, or a combination containing equal amounts of the two drugs of 0.36 +/- 0.1 microgram kg-1. The pressor response to adrenaline was reduced (P less than 0.01) by UK-52046 but not by atenolol or the combination of both drugs. 2. In a group of 6 dogs with multiventricular ectopic beats 24 h after coronary artery ligation (CAL), UK-52046, 32 micrograms kg-1, increased the number of sinus beats in each 5 min period from 137 +/- 47 to 662 +/- 99 (P less than 0.01); this was associated with a significant (P less than 0.01) fall in blood pressure. Atenolol in doses of up to 800 micrograms kg-1 had no effect. 3. UK-52046, 3.7 +/- 1.4 micrograms kg-1, prevented adrenaline-induced arrhythmias 3-4 days after CAL in 6/6 conscious dogs; atenolol in doses of up to 100 micrograms kg-1 produced an 84.4 +/- 7.4% reduction in the number of ventricular ectopic beats. A combination containing 3.7 +/- 1.1 micrograms kg-1 of each drug prevented the arrhythmia in 6/6 dogs. The pressor response to adrenaline was attenuated (P less than 0.05) by UK-52046, but resting blood pressure was unaffected by the different treatments. An increase (P less than 0.01) in heart rate was associated with both UK-52046 and the combination. 4. Neither UK-52046 (doses up to 64 micrograms kg-1) nor atenolol (up to 800 micrograms kg-1) had any effect upon ouabain-induced arrhythmias in 2 groups of 6 anaesthetized dogs. 5. In a study of the early (1a/1b) arrhythmias of acute myocardial ischaemia, the total number of ventricular ectopic beats occurring within 30 min of CAL was not reduced by 4 micrograms kg-1 UK-52046 but fell (P less than 0.01 compared with placebo) after 8 micrograms kg-1 [median values with ranges for placebo, 4 micrograms kg-1 and 8 micrograms kg-1 respectively 190 (4

  18. Prevention and Treatment of Arrhythmia

    MedlinePlus

    ... Venous Thromboembolism Aortic Aneurysm More Prevention & Treatment of Arrhythmia Updated:Dec 21,2016 Do you need treatment? ... Trials . This content was last reviewed September 2016. Arrhythmia • Home • About Arrhythmia • Why Arrhythmia Matters • Understand Your ...

  19. Understand Your Risk for Arrhythmia

    MedlinePlus

    ... Thromboembolism Aortic Aneurysm More Understand Your Risk for Arrhythmia Updated:Dec 21,2016 Expected changes in heart ... spirits.) This content was last reviewed September 2016. Arrhythmia • Home • About Arrhythmia • Why Arrhythmia Matters • Understand Your ...

  20. Arrhythmias in the Heart Transplant Patient

    PubMed Central

    Hamon, David; Taleski, Jane; Vaseghi, Marmar; Shivkumar, Kalyanam

    2014-01-01

    Orthotopic heart transplantation (OHT) is currently the most effective long-term therapy for patients with end-stage cardiac disease, even as left ventricular devices show markedly improved outcomes. As surgical techniques and immunosuppressive regimens have been refined, short-term mortality caused by sepsis has decreased, while morbidity caused by repeated rejection episodes and vasculopathy has increased, and is often manifested by arrhythmias. These chronic transplant complications require early and aggressive multidisciplinary treatment. Understanding the relationship between arrhythmias and these complications in the acute and chronic stages following OHT is critical in improving patient prognosis, as arrhythmias may be the earliest or sole presentation. Finally, decentralised/ denervated hearts represent a unique opportunity to investigate the underlying mechanisms of arrhythmias. PMID:26835083

  1. Structured electronic documentation (SED) cardiac surgery and PowerNote- a pilot project.

    PubMed

    Pellegrini, Daniel P; Raghu, Sujatha; Waechter, Darcy K

    2005-01-01

    User Specific templates were created through Cerner PowerNote to fit the need for improving the turnaround time for the Operative notes for Cardiac Surgery Patients. This eliminated the lag time of 37.5hours for Intensive Care Unit staff to access the detailed Operative notes on Cardiac surgery patients.

  2. Increased Myofilament Ca2+-Sensitivity and Arrhythmia Susceptibility

    PubMed Central

    Huke, Sabine; Knollmann, Bjorn C.

    2010-01-01

    Increased myofilament Ca2+ sensitivity, a common attribute of inherited and acquired cardiomyopathies, is often associated with cardiac arrhythmias. Accumulating evidence supports that increased myofilament Ca2+ sensitivity is an independent risk factor for arrhythmias, but the underlying molecular mechanism remains unclear. This review focuses on potential mechanisms how myofilament Ca2+ sensitivity may affect cardiac excitation and leads to the generation of arrhythmias. We discuss in detail the downstream effects of increased myofilament Ca2+ sensitivity, i.e. altered Ca2+ buffering/handling, impaired energy metabolism and increased mechanical stretch, and how they may contribute to the proarrhythmic effect. PMID:20097204

  3. Altered Calcium Handling and Ventricular Arrhythmias in Acute Ischemia

    PubMed Central

    Baumeister, Peter; Quinn, T. Alexander

    2016-01-01

    Acute ischemia results in deadly cardiac arrhythmias that are a major contributor to sudden cardiac death (SCD). The electrophysiological changes involved have been extensively studied, yet the mechanisms of ventricular arrhythmias during acute ischemia remain unclear. What is known is that during acute ischemia both focal (ectopic excitation) and nonfocal (reentry) arrhythmias occur, due to an interaction of altered electrical, mechanical, and biochemical properties of the myocardium. There is particular interest in the role that alterations in intracellular calcium handling, which cause changes in intracellular calcium concentration and to the calcium transient, play in ischemia-induced arrhythmias. In this review, we briefly summarize the known contributors to ventricular arrhythmias during acute ischemia, followed by an in-depth examination of the potential contribution of altered intracellular calcium handling, which may include novel targets for antiarrhythmic therapy. PMID:28008297

  4. Systems Pharmacology of Arrhythmias

    PubMed Central

    Berger, Seth I.; Ma’ayan, Avi; Iyengar, Ravi

    2011-01-01

    Long-QT syndrome (LQTS) is a congenital or drug-induced change in electrical activity of the heart that can lead to fatal arrhythmias. Mutations in 12 genes encoding ion channels and associated proteins are linked with congenital LQTS. With a computational systems biology approach, we found that gene products involved in LQTS formed a distinct functional neighborhood within the human interactome. Other diseases form similarly selective neighborhoods, and comparison of the LQTS neighborhood with other disease-centered neighborhoods suggested a molecular basis for associations between seemingly unrelated diseases that have increased risk of cardiac complications. By combining the LQTS neighborhood with published genome-wide association study data, we identified previously unknown single-nucleotide polymorphisms likely to affect the QT interval. We found that targets of U.S. Food and Drug Administration (FDA)–approved drugs that cause LQTS as an adverse event were enriched in the LQTS neighborhood. With the LQTS neighborhood as a classifier, we predicted drugs likely to have risks for QT effects and we validated these predictions with the FDA’s Adverse Events Reporting System, illustrating how network analysis can enhance the detection of adverse drug effects associated with drugs in clinical use. Thus, the identification of disease-selective neighborhoods within the human interactome can be useful for predicting new gene variants involved in disease, explaining the complexity underlying adverse drug side effects, and predicting adverse event susceptibility for new drugs. PMID:20407125

  5. Short-term secondhand smoke exposure decreases heart rate variability and increases arrhythmia susceptibility in mice.

    PubMed

    Chen, Chao-Yin; Chow, Drin; Chiamvimonvat, Nipavan; Glatter, Kathryn A; Li, Ning; He, Yuxia; Pinkerton, Kent E; Bonham, Ann C

    2008-08-01

    Exposure to secondhand smoke (SHS), a major indoor air pollutant, is linked to increased cardiovascular morbidity and mortality, including cardiac arrhythmias. However, the mechanisms underlying the epidemiological findings are not well understood. Impaired cardiac autonomic function, indexed by reduced heart rate variability (HRV), may represent an underlying cause. The present study takes advantage of well-defined short-term SHS exposure (3 days, 6 h/day) on HRV and the susceptibility to arrhythmia in mice. With the use of electrocardiograph telemetry recordings in conscious mice, HRV parameters in the time domain were measured during the night after each day of exposure and 24 h after 3 days of exposure to either SHS or filtered air. The susceptibility to arrhythmia was determined after 3 days of exposure. Exposure to a low concentration of SHS [total suspended particle (TSP), 2.4 +/- 3.2; and nicotine, 0.3 +/- 0.1 mg/m(3)] had no significant effect on HRV parameters. In contrast, the exposure to a higher but still environmentally relevant concentration of SHS (TSP, 30 +/- 1; and nicotine, 5 +/- 1 mg/m(3)) significantly reduced HRV starting after the first day of exposure and continuing 24 h after the last day of exposure. Moreover, the exposed mice showed a significant increase in ventricular arrhythmia susceptibility and atrioventricular block. The data suggest that SHS exposure decreased HRV beyond the exposure period and was associated with an increase in arrhythmia susceptibility. The data provide insights into possible mechanisms underlying documented increases in cardiovascular morbidity and mortality in humans exposed to SHS.

  6. Teaching Cardiac Electrophysiology Modeling to Undergraduate Students: Laboratory Exercises and GPU Programming for the Study of Arrhythmias and Spiral Wave Dynamics

    ERIC Educational Resources Information Center

    Bartocci, Ezio; Singh, Rupinder; von Stein, Frederick B.; Amedome, Avessie; Caceres, Alan Joseph J.; Castillo, Juan; Closser, Evan; Deards, Gabriel; Goltsev, Andriy; Ines, Roumwelle Sta.; Isbilir, Cem; Marc, Joan K.; Moore, Diquan; Pardi, Dana; Sadhu, Sandeep; Sanchez, Samuel; Sharma, Pooja; Singh, Anoopa; Rogers, Joshua; Wolinetz, Aron; Grosso-Applewhite, Terri; Zhao, Kai; Filipski, Andrew B.; Gilmour, Robert F., Jr.; Grosu, Radu; Glimm, James; Smolka, Scott A.; Cherry, Elizabeth M.; Clarke, Edmund M.; Griffeth, Nancy; Fenton, Flavio H.

    2011-01-01

    As part of a 3-wk intersession workshop funded by a National Science Foundation Expeditions in Computing award, 15 undergraduate students from the City University of New York collaborated on a study aimed at characterizing the voltage dynamics and arrhythmogenic behavior of cardiac cells for a broad range of physiologically relevant conditions…

  7. Evidence Based Review: Risk of Cardiac Rhythm Problems During Spaceflight

    NASA Technical Reports Server (NTRS)

    Platts, Steven H.; Stenger, Michael B.; Phillips, Tiffany R.; Brown, Angela K.; Arzeno, Natalia M.; Levine, Benjamin; Summers, Richard

    2009-01-01

    Very little research has systematically evaluated the prevalence (or potential risk) of cardiac arrhythmias during space flight. There are several observational reports of non life-threatening but potentially concerning arrhythmias. At least two potential risk factors for arrhythmias have been reported either during or immediately after space flight: cardiac atrophy and a prolonged QTc interval. The potential severity of the mission impact of a serious arrhythmia requires that a systematic evaluation be conducted of the risk of arrhythmia due to space flight.

  8. Arrhythmias in viral myocarditis and pericarditis.

    PubMed

    Baksi, A John; Kanaganayagam, G Sunthar; Prasad, Sanjay K

    2015-06-01

    Acute viral myocarditis and acute pericarditis are self-limiting conditions that run a benign course and that may not involve symptoms that lead to medical assessment. However, ventricular arrhythmia is frequent in viral myocarditis. Myocarditis is thought to account for a large proportion of sudden cardiac deaths in young people without prior structural heart disease. Identification of acute myocarditis either with or without pericarditis is therefore important. However, therapeutic interventions are limited and nonspecific. Identifying those at greatest risk of a life-threatening arrhythmia is critical to reducing the mortality. This review summarizes current understanding of this challenging area in which many questions remain.

  9. Remote Arrhythmia Monitoring System Developed

    NASA Technical Reports Server (NTRS)

    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.

  10. Arrhythmias in peripartum cardiomyopathy.

    PubMed

    Honigberg, Michael C; Givertz, Michael M

    2015-06-01

    Peripartum cardiomyopathy (PPCM) is a complication of late pregnancy and the early postpartum period characterized by dilated cardiomyopathy and heart failure with reduced ejection fraction. Approximately half of women fail to recover left ventricular function. Standard management of heart failure is indicated, with some exceptions for women who are predelivery or breastfeeding. Atrial and ventricular arrhythmias are reported in PPCM, but the frequency of arrhythmias in this condition is not well characterized. Management of PPCM-associated arrhythmias may include antiarrhythmic drugs, catheter ablation, and wearable or implantable cardioverter-defibrillators. Further research is needed on the prevalence, natural history, and optimal management of arrhythmias in PPCM.

  11. Perinatal Arrhythmias: Diagnosis and Management

    PubMed Central

    Strasburger, Janette F.; Cheulkar, Bageshree; Wichman, Heather J.

    2012-01-01

    The final common pathway to death in all of us is an arrhythmia, yet we still know far too little about the contribution of conduction abnormalities and arrhythmias to the compromised states of the human fetus. At no other time in the human life cycle is the human being at more risk of unexplained and unexpected death than during the prenatal period. The risk of sudden death from 20 to 40 weeks gestation is 6 to 12 deaths/1000 fetuses/year. This is equal to, and in some ethnic groups HIGHER, than the risk of death in the adult population with known coronary artery disease over the same time frame (6 to 12 deaths/1000 patients/year). Because only a small percentage of the United States population is pregnant each year, because fetal demise is not often acknowledged through public displays such as funerals, and finally because fetal death is culturally accepted to a much greater extent than it should be, this critically important area of women’s healthcare has not had the technological advances that have been seen in adult cardiac intensive care and other areas of medicine. Fetal cardiac deaths may be preventable and the diseases that lead to these deaths are often treatable, especially if the sophistication of our modern ICU’s could somehow be translated to the prenatal monitoring arena. PMID:18063110

  12. Cardiac Sarcoidosis.

    PubMed

    Birnie, David; Ha, Andrew C T; Gula, Lorne J; Chakrabarti, Santabhanu; Beanlands, Rob S B; Nery, Pablo

    2015-12-01

    Studies suggest clinically manifest cardiac involvement occurs in 5% of patients with pulmonary/systemic sarcoidosis. The principal manifestations of cardiac sarcoidosis (CS) are conduction abnormalities, ventricular arrhythmias, and heart failure. Data indicate that an 20% to 25% of patients with pulmonary/systemic sarcoidosis have asymptomatic (clinically silent) cardiac involvement. An international guideline for the diagnosis and management of CS recommends that patients be screened for cardiac involvement. Most studies suggest a benign prognosis for patients with clinically silent CS. Immunosuppression therapy is advocated for clinically manifest CS. Device therapy, with implantable cardioverter defibrillators, is recommended for some patients.

  13. Development of device therapy for ventricular arrhythmias.

    PubMed

    Holley, Loraine K

    2007-06-01

    The past 25 years have seen the implantable cardioverter defibrillator emerge as the treatment of choice for ventricular arrhythmias with reduction in size but increased therapeutic options. Understanding the complex mechanisms of ventricular arrhythmias and defibrillation in normal and diseased hearts has been the focus of many research teams including that of John Uther at the Westmead Hospital Department of Cardiology. Marked improvements in capacitor and battery technologies, arrhythmia discrimination, pacing algorithms, shock waveforms and monitoring capabilities enable wider use and patient acceptance. Emergence of cardiac resynchronisation therapy and the implantable defibrillator for treatment of chronic heart failure is not only giving quality of life and extended survival for heart failure patients but has also cast new light on the evolution of heart failure.

  14. Neural defects and cardiac arrhythmia in fish larvae following embryonic exposure to 2,2',4,4'-tetrabromodiphenyl ether (PBDE 47).

    PubMed

    Lema, Sean C; Schultz, Irvin R; Scholz, Nathaniel L; Incardona, John P; Swanson, Penny

    2007-05-31

    Polybrominated diphenyl ethers (PBDEs) are added to plastics, polyurethane foam, and textiles as a flame retardant. While PBDEs play a key role in reducing loss of human life and property from fires, these flame retardants have become pervasive organic contaminants in the environment and in the tissues of fish, birds, marine mammals, and humans. Levels of PBDEs in wildlife and humans continue to rise, raising concerns about potential ecological and health risks associated with exposure to these chemicals. Nevertheless, there is little currently known about the toxicological effects of PBDE exposure. Here, we examined the developmental toxicity of the PBDE congener 2,2',4,4'-tetrabromodiphenyl ether (PBDE 47) using the zebrafish (Danio rerio) as an ontogenetic model. Zebrafish embryos were exposed continuously to dissolved phase PBDE 47 (100-5000 microg/l) beginning 3-5 h post-fertilization (hpf). Fish treated with the highest concentrations of PBDE 47 delayed hatching, had reduced growth post-hatching, and displayed an abnormal dorsal curvature of the body with flexion at the hindbrain. By 96h post-fertilization larvae exposed to PBDE 47 had significant tachycardia, which progressed into atrioventricular block arrhythmias. Microinjection of fluorescent dye into the hindbrain ventricle revealed that cerebrospinal fluid in the neural tube and brain ventricles flowed more slowly in fish larvae exposed to PBDE 47, a likely etiology for the dorsal curvature. Similar, though much less pronounced, developmental toxicity also occurred in larvae exposed to PBDE 47 only for a 20h period during early embryogenesis (3-23 hpf), suggesting that PBDEs incorporated in lipid of the egg are bioavailable and cause toxicity later in life. Taken together, this work indicates that exposure to PBDE 47 can cause morphological abnormalities, impair cardiovascular function and cerebrospinal fluid flow, and provides a tractable starting point for using the zebrafish model to explore

  15. [Supraventricular arrhythmia: electrocardiographic aspects].

    PubMed

    Bayés de Luna, Antoni

    2016-12-23

    Supraventricular arrhythmias are one of the main causes of medical consultation. They may also be the clinical presentation of various cardiovascular diseases and a marker of sudden death. The correct diagnosis of these arrhythmias could be a challenge. The purpose of this narrative review is to update succinctly on the topic.

  16. Multiple nickel-sensitive targets elicit cardiac arrhythmia in isolated mouse hearts after pituitary adenylate cyclase-activating polypeptide-mediated chronotropy.

    PubMed

    Tevoufouet, Etienne E; Nembo, Erastus N; Distler, Fabian; Neumaier, Felix; Hescheler, Jürgen; Nguemo, Filomain; Schneider, Toni

    2017-03-01

    The pituitary adenylate cyclase-activating polypeptide (PACAP)-27 modulates various biological processes, from the cellular level to function specification. However, the cardiac actions of this neuropeptide are still under intense studies. Using control (+|+) and mice lacking (-|-) either R-type (Cav2.3) or T-type (Cav3.2) Ca(2+) channels, we investigated the effects of PACAP-27 on cardiac activity of spontaneously beating isolated perfused hearts. Superfusion of PACAP-27 (20nM) caused a significant increase of baseline heart frequency in Cav2.3(+|+) (156.9±10.8 to 239.4±23.4 bpm; p<0.01) and Cav2.3(-|-) (190.3±26.4 to 270.5±25.8 bpm; p<0.05) hearts. For Cav3.2, the heart rate was significantly increased in Cav3.2(-|-) (133.1±8.5 bpm to 204.6±27.9 bpm; p<0.05) compared to Cav3.2(+|+) hearts (185.7±11.2 bpm to 209.3±22.7 bpm). While the P wave duration and QTc interval were significantly increased in Cav2.3(+|+) and Cav2.3(-|-) hearts following PACAP-27 superfusion, there was no effect in Cav3.2(+|+) and Cav3.2(-|-) hearts. The positive chronotropic effects observed in the four study groups, as well as the effect on P wave duration and QTc interval were abolished in the presence of Ni(2+) (50μM) and PACAP-27 (20nM) in hearts from Cav2.3(+|+) and Cav2.3(-|-) mice. In addition to suppressing PACAP's response, Ni(2+) also induced conduction disturbances in investigated hearts. In conclusion, the most Ni(2+)-sensitive Ca(2+) channels (R- and T-type) may modulate the PACAP signaling cascade during cardiac excitation in isolated mouse hearts, albeit to a lesser extent than other Ni(2+)-sensitive targets.

  17. Levels of circulating anti-muscarinic and anti-adrenergic antibodies and their effect on cardiac arrhythmias and dysautonomia in murine models of Chagas disease.

    PubMed

    Daliry, Anissa; Pereira, Isabela Resende; Pereira-Junior, Pedro Paulo; Ramos, Isalira Peroba; Vilar-Pereira, Glaucia; Silvares, Raquel Rangel; Lannes-Vieira, Joseli; Campos De Carvalho, Antônio Carlos

    2014-11-01

    SUMMARY Antibodies (Ab) recognizing G-protein coupled receptors, such as β 1 and β 2 adrenergic (anti-β 1-AR and anti-β 2-AR, respectively) and muscarinic cholinergic receptors (anti-M2-CR) may contribute to cardiac damage, however their role in chronic chagasic cardiomyopathy is still controversial. We describe that Trypanosoma cruzi-infected C3H/He mice show increased P and QRS wave duration, and PR and QTc intervals, while the most significant ECG alterations in C57BL/6 are prolonged P wave and PR interval. Echocardiogram analyses show right ventricle dilation in infected animals of both mouse lineages. Analyses of heart rate variability (HRV) in chronically infected C3H/He mice show no alteration of the evaluated parameters, while C57BL/6 infected mice display significantly lower values of HRV components, suggesting autonomic dysfunction. The time-course analysis of anti-β 1-AR, anti-β 2-AR and anti-M2-CR Ab titres in C3H/He infected mice indicate that anti-β 1-AR Ab are detected only in the chronic phase, while anti-β 2-AR and anti-M2-CR are observed in the acute phase, diminish at 60 dpi and increase again in the chronic phase. Chronically infected C57BL/6 mice presented a significant increase in only anti-M2-CR Ab titres. Furthermore, anti-β 1-AR, anti-β 2-AR and anti-M2-CR, exhibit significantly higher prevalence in chronically T. cruzi-infected C3H/He mice when compared with C57BL/6. These observations suggest that T. cruzi infection leads to host-specific cardiac electric alterations.

  18. Recent advances in genetic testing and counseling for inherited arrhythmias.

    PubMed

    Mizusawa, Yuka

    2016-10-01

    Inherited arrhythmias, such as cardiomyopathies and cardiac ion channelopathies, along with coronary heart disease (CHD) are three most common disorders that predispose adults to sudden cardiac death. In the last three decades, causal genes in inherited arrhythmias have been successfully identified. At the same time, it has become evident that the genetic architectures are more complex than previously known. Recent advancements in DNA sequencing technology (next generation sequencing) have enabled us to study such complex genetic traits. This article discusses indications for genetic testing of patients with inherited arrhythmias. Further, it describes the benefits and challenges that we face in the era of next generation sequencing. Finally, it briefly discusses genetic counseling, in which a multidisciplinary approach is required due to the increased complexity of the genetic information related to inherited arrhythmias.

  19. Diagnosis and Treatment of Fetal Arrhythmia

    PubMed Central

    Wacker-Gussmann, Annette; Strasburger, Janette F.; Cuneo, Bettina F.; Wakai, Ronald T.

    2014-01-01

    Detection and careful stratification of fetal heart rate (FHR) is extremely important in all pregnancies. The most lethal cardiac rhythm disturbances occur during apparently normal pregnancies where FHR and rhythmare regular and within normal or low-normal ranges. These hidden depolarization and repolarization abnormalities, associated with genetic ion channelopathies cannot be detected by echocardiography, and may be responsible for up to 10% of unexplained fetal demise, prompting a need for newer and better fetal diagnostic techniques. Other manifest fetal arrhythmias such as premature beats, tachycardia, and bradycardia are commonly recognized. Heart rhythm diagnosis in obstetrical practice is usually made by M-mode and pulsed Doppler fetal echocardiography, but not all fetal cardiac time intervals are captured by echocardiographic methods. This article reviews different types of fetal arrhythmias, their presentation and treatment strategies, and gives an overview of the present and future diagnostic techniques. PMID:24858320

  20. Overview of fetal arrhythmias

    PubMed Central

    Srinivasan, Shardha; Strasburger, Janette

    2012-01-01

    Purpose of review Though fetal arrhythmias account for a small proportion of referrals to a fetal cardiologist, they may be associated with significant morbidity and mortality. The present review outlines the current literature with regard to the diagnosis and, in brief, some management strategies in fetal arrhythmias. Recent findings Advances in echocardiography have resulted in significant improvements in our ability to elucidate the mechanism of arrhythmia at the bedside. At the same time, fetal magnetocardiography is broadening our understanding of mechanisms of arrhythmia especially as it pertains to ventricular arrhythmias and congenital heart block. It provides a unique window to study electrical properties of the fetal heart, unlike what has been available to date. Recent reports of bedside use of fetal ECG make it a promising new technology. The underlying mechanisms resulting in immune-mediated complete heart block in a small subset of ‘at-risk’ fetuses is under investigation. Summary There have been great strides in noninvasive diagnosis of fetal arrhythmias. However, we still need to improve our knowledge of the electromechanical properties of the fetal heart as well as the mechanisms of arrhythmia to further improve outcomes. Multiinstitutional collaborative studies are needed to help answer some of the questions regarding patient, drug selection and management algorithms. PMID:18781114

  1. Subcutaneous Nerve Activity and Spontaneous Ventricular Arrhythmias in Ambulatory Dogs

    PubMed Central

    Doytchinova, Anisiia; Patel, Jheel; Zhou, Shengmei; Chen, Lan S.; Lin, Hongbo; Shen, Changyu; Everett, Thomas H; Lin, Shien-Fong; Chen, Peng-Sheng

    2014-01-01

    Background Stellate ganglion nerve activity (SGNA) is important in ventricular arrhythmogenesis. However, because thoracotomy is needed to access the stellate ganglion, it is difficult to use SGNA for risk stratification. Objective To test the hypothesis that subcutaneous nerve activity (SCNA) in canines can be used to estimate SGNA and predict ventricular arrhythmia. Methods We implanted radio transmitters to continuously monitor left stellate ganglion and subcutaneous electrical activities in 7 ambulatory dogs with myocardial infarction, complete heart block and nerve growth factor infusion to the left stellate ganglion. Results Spontaneous ventricular tachycardia (VT) or ventricular fibrillation (VF) was documented in each dog. SCNA preceded a combined 61 episodes of VT and VF, 61 frequent bigeminy or couplets and 61 premature ventricular contractions within 15 s in 70%, 59% and 61% of arrhythmias, respectively. Similar incidence of 75%, 69% and 62% was noted for SGNA. Progressive increase in SCNA (48.9 (95% CI 39.3–58.5) vs. 61.8 (95% CI 45.9–77.6) vs. 75.1 (95% CI 57.5–92.7) mV-s) and SGNA (48.6 (95% CI 40.9–56.3) vs. 58.5 (95% CI 47.5–69.4) vs. 69.0 (95% CI 53.8–84.2) mV-s) integrated over 20 s intervals was demonstrated 60 s, 40 s and 20 s prior to VT/VF (p<0.05). The Pearson’s correlation coefficient for integrated SCNA and SGNA was 0.73±0.18 (p<0.0001 for all dogs, n=5). Both SCNA and SGNA exhibited circadian variation. Conclusions SCNA can be used as an estimate of SGNA to predict susceptibility to VT and VF in a canine model of ventricular arrhythmia and sudden cardiac death. PMID:25460171

  2. Carbon monoxide and lethal arrhythmias

    SciTech Connect

    Farber, J.P.; Schwartz, P.J.; Vanoli, E.; Stramba-Badiale, M.; De Ferrari, G.M. )

    1990-12-01

    The effect of acute exposure to carbon monoxide on ventricular arrhythmias was studied in a previously described chronically maintained animal model of sudden cardiac death. In 60 percent of dogs with a healed anterior myocardial infarction, the combination of mild exercise and acute myocardial ischemia induces ventricular fibrillation. The events in this model are highly reproducible, thus allowing study by internal control analysis. Dogs that develop ventricular fibrillation during the test of exercise and acute myocardial ischemia are considered at high risk for sudden death and are defined as 'susceptible'; dogs that survive the test without a fatal arrhythmia are considered at low risk for sudden death and are defined as 'resistant.' In the current study, the effects of carboxyhemoglobin levels ranging from 5 to 15 percent were tested in resistant and susceptible dogs. A trend toward higher heart rates was observed at all levels of carboxyhemoglobin, although significant differences were observed only with 15 percent carboxyhemoglobin. This trend was observed at rest and during exercise in both resistant and susceptible dogs. In resistant animals, in which acute myocardial ischemia is typically associated with bradycardia even under the control condition, this reflex response occurred earlier and was augmented after exposure to carbon monoxide. This effect may depend on the increased hypoxic challenge caused by carbon monoxide, and thus on an augmentation of the neural reflex activation or a sensitization of the sinus node to acetylcholine induced by hypoxia. In both resistant and susceptible dogs, carbon monoxide exposure induced a worsening of ventricular arrhythmias in a minority of cases. This worsening was not reproducible in subsequent trials. These data indicate that acute exposure to carbon monoxide is seldom arrhythmogenic in dogs that have survived myocardial infarction. (Abstract Truncated)

  3. The role of M cells and the long QT syndrome in cardiac arrhythmias: Simulation studies of reentrant excitations using a detailed electrophysiological model

    NASA Astrophysics Data System (ADS)

    Henry, Hervé; Rappel, Wouter-Jan

    2004-03-01

    In this numerical study, we investigate the role of intrinsic heterogeneities of cardiac tissue due to M cells in the generation and maintenance of reentrant excitations using the detailed Luo-Rudy dynamic model. This model has been extended to include a description of the long QT 3 syndrome, and is studied in both one dimension, corresponding to a cable traversing the ventricular wall, and two dimensions, representing a transmural slice. We focus on two possible mechanisms for the generation of reentrant events. We first investigate if early-after-depolarizations occurring in M cells can initiate reentry. We find that, even for large values of the long QT strength, the electrotonic coupling between neighboring cells prevents early-after-depolarizations from creating a reentry. We then study whether M cell domains, with their slow repolarization, can function as wave blocks for premature stimuli. We find that the inclusion of an M cell domain can result in some cases in reentrant excitations and we determine the lifetime of the reentry as a function of the size and geometry of the domain and of the strength of the long QT syndrome.

  4. High-efficiency multiplex capillary electrophoresis single strand conformation polymorphism (multi-CE-SSCP) mutation screening of SCN5A: a rapid genetic approach to cardiac arrhythmia.

    PubMed

    Hofman-Bang, J; Behr, E R; Hedley, P; Tfelt-Hansen, J; Kanters, J K; Haunsøe, S; McKenna, W J; Christiansen, M

    2006-06-01

    Mutations in the SCN5A gene coding for the alpha-subunit of the cardiac Na(+) ion channel cause long QT syndrome, Brugada syndrome, idiopathic ventricular fibrillation, sick sinus node syndrome, progressive conduction disease, dilated cardiomyopathy and atrial standstill. These diseases exhibit variable expressivity, and identification of gene carriers is clinically important, particularly in sudden infant and adult death syndromes. The SCN5A gene comprises 28 exons distributed over 100 kbp of genomic sequence at chromosome 3p21. Disease-causing mutations are private and scattered over the DNA sequence, making it difficult to screen for specific mutations. We developed a multiplex capillary-electrophoresis single-strand conformation polymorphism (Multi-CE-SSCP) mutation screening protocol on the ABI 3100 platform and applied it to 10 previously slab-gel SSCP identified mutations and SNPs and used it to identify one novel deletion. The method is highly efficient, with a turnover of 23 patients per 24 h and a false positive rate of 0.5% of the analyzed amplicons. Each variant has a particular elution pattern, and all 20 carriers of the H558R polymorphism out of 57 persons were correctly identified. We suggest that the method could become part of routine work-up of patients with suspicious syncope and of members of families with sudden unexplained death.

  5. [Arrhythmia and sport].

    PubMed

    Saoudi, N; Yaici, K; Zarkane, N; Darmon, J P; Rinaldi, J P; Brunner, P; Ricard, P; Mourou, M Y

    2005-12-01

    Sports arrhythmia has gained wide attention with the mediatization of the death of famous sports stars. Sport strongly modifies the structure of the heart with the development of left ventricular hypertrophy which may be difficult to differentiate from that due to doping. Intense training modifies also the resting electrocardiogram with appearance of signs of left ventricular hypertrophy whereas resting sinus bradycardia and atrioventricular conduction disturbances usually reverts upon exertion. Accordingly, arrhythmia may develop ranging from extrasystoles to atrial fibrillation and even sudden death. Recent data suggest that if benign arrhythmia may be the result of the sole intense training and are reversible, malignant ventricular arrhythmia and sudden death mostly occur in unknown structural heart disease. Hypertrophic cardiomyopathy is amongst the most frequent post mortem diagnosis in this situation. Doping is now present in many sports and further threatens the athlete in the safe practice of sport.

  6. Perspective: a dynamics-based classification of ventricular arrhythmias.

    PubMed

    Weiss, James N; Garfinkel, Alan; Karagueuzian, Hrayr S; Nguyen, Thao P; Olcese, Riccardo; Chen, Peng-Sheng; Qu, Zhilin

    2015-05-01

    Despite key advances in the clinical management of life-threatening ventricular arrhythmias, culminating with the development of implantable cardioverter-defibrillators and catheter ablation techniques, pharmacologic/biologic therapeutics have lagged behind. The fundamental issue is that biological targets are molecular factors. Diseases, however, represent emergent properties at the scale of the organism that result from dynamic interactions between multiple constantly changing molecular factors. For a pharmacologic/biologic therapy to be effective, it must target the dynamic processes that underlie the disease. Here we propose a classification of ventricular arrhythmias that is based on our current understanding of the dynamics occurring at the subcellular, cellular, tissue and organism scales, which cause arrhythmias by simultaneously generating arrhythmia triggers and exacerbating tissue vulnerability. The goal is to create a framework that systematically links these key dynamic factors together with fixed factors (structural and electrophysiological heterogeneity) synergistically promoting electrical dispersion and increased arrhythmia risk to molecular factors that can serve as biological targets. We classify ventricular arrhythmias into three primary dynamic categories related generally to unstable Ca cycling, reduced repolarization, and excess repolarization, respectively. The clinical syndromes, arrhythmia mechanisms, dynamic factors and what is known about their molecular counterparts are discussed. Based on this framework, we propose a computational-experimental strategy for exploring the links between molecular factors, fixed factors and dynamic factors that underlie life-threatening ventricular arrhythmias. The ultimate objective is to facilitate drug development by creating an in silico platform to evaluate and predict comprehensively how molecular interventions affect not only a single targeted arrhythmia, but all primary arrhythmia dynamics

  7. Perioperative management of antiplatelet therapy in patients with coronary stents undergoing cardiac and non-cardiac surgery: a consensus document from Italian cardiological, surgical and anaesthesiological societies.

    PubMed

    Rossini, Roberta; Musumeci, Giuseppe; Visconti, Luigi Oltrona; Bramucci, Ezio; Castiglioni, Battistina; De Servi, Stefano; Lettieri, Corrado; Lettino, Maddalena; Piccaluga, Emanuela; Savonitto, Stefano; Trabattoni, Daniela; Capodanno, Davide; Buffoli, Francesca; Parolari, Alessandro; Dionigi, Gianlorenzo; Boni, Luigi; Biglioli, Federico; Valdatta, Luigi; Droghetti, Andrea; Bozzani, Antonio; Setacci, Carlo; Ravelli, Paolo; Crescini, Claudio; Staurenghi, Giovanni; Scarone, Pietro; Francetti, Luca; D'Angelo, Fabio; Gadda, Franco; Comel, Andrea; Salvi, Luca; Lorini, Luca; Antonelli, Massimo; Bovenzi, Francesco; Cremonesi, Alberto; Angiolillo, Dominick J; Guagliumi, Giulio

    2014-05-01

    Optimal perioperative antiplatelet therapy in patients with coronary stents undergoing surgery still remains poorly defined and a matter of debate among cardiologists, surgeons and anaesthesiologists. Surgery represents one of the most common reasons for premature antiplatelet therapy discontinuation, which is associated with a significant increase in mortality and major adverse cardiac events, in particular stent thrombosis. Clinical practice guidelines provide little support with regard to managing antiplatelet therapy in the perioperative phase in the case of patients with non-deferrable surgical interventions and/or high haemorrhagic risk. Moreover, a standard definition of ischaemic and haemorrhagic risk has never been determined. Finally, recommendations shared by cardiologists, surgeons and anaesthesiologists are lacking. The present consensus document provides practical recommendations on the perioperative management of antiplatelet therapy in patients with coronary stents undergoing surgery. Cardiologists, surgeons and anaesthesiologists have contributed equally to its creation. On the basis of clinical and angiographic data, the individual thrombotic risk has been defined. All surgical interventions have been classified according to their inherent haemorrhagic risk. A consensus on the optimal antiplatelet regimen in the perioperative phase has been reached on the basis of the ischaemic and haemorrhagic risk. Aspirin should be continued perioperatively in the majority of surgical operations, whereas dual antiplatelet therapy should not be withdrawn for surgery in the case of low bleeding risk. In selected patients at high risk for both bleeding and ischaemic events, when oral antiplatelet therapy withdrawal is required, perioperative treatment with short-acting intravenous glycoprotein IIb/IIIa inhibitors (tirofiban or eptifibatide) should be taken into consideration.

  8. Types of Arrhythmia in Children

    MedlinePlus

    ... Disease Venous Thromboembolism Aortic Aneurysm More Types of Arrhythmia in Children Updated:Dec 21,2016 There are ... put in. Checklist for Parents of Children with Arrhythmias Learn CPR and emergency procedures Parents of all ...

  9. Human cardiac systems electrophysiology and arrhythmogenesis: iteration of experiment and computation.

    PubMed

    Holzem, Katherine M; Madden, Eli J; Efimov, Igor R

    2014-11-01

    Human cardiac electrophysiology (EP) is a unique system for computational modelling at multiple scales. Due to the complexity of the cardiac excitation sequence, coordinated activity must occur from the single channel to the entire myocardial syncytium. Thus, sophisticated computational algorithms have been developed to investigate cardiac EP at the level of ion channels, cardiomyocytes, multicellular tissues, and the whole heart. Although understanding of each functional level will ultimately be important to thoroughly understand mechanisms of physiology and disease, cardiac arrhythmias are expressly the product of cardiac tissue-containing enough cardiomyocytes to sustain a reentrant loop of activation. In addition, several properties of cardiac cellular EP, that are critical for arrhythmogenesis, are significantly altered by cell-to-cell coupling. However, relevant human cardiac EP data, upon which to develop or validate models at all scales, has been lacking. Thus, over several years, we have developed a paradigm for multiscale human heart physiology investigation and have recovered and studied over 300 human hearts. We have generated a rich experimental dataset, from which we better understand mechanisms of arrhythmia in human and can improve models of human cardiac EP. In addition, in collaboration with computational physiologists, we are developing a database for the deposition of human heart experimental data, including thorough experimental documentation. We anticipate that accessibility to this human heart dataset will further human EP computational investigations, as well as encourage greater data transparency within the field of cardiac EP.

  10. Human cardiac systems electrophysiology and arrhythmogenesis: iteration of experiment and computation

    PubMed Central

    Holzem, Katherine M.; Madden, Eli J.; Efimov, Igor R.

    2014-01-01

    Human cardiac electrophysiology (EP) is a unique system for computational modelling at multiple scales. Due to the complexity of the cardiac excitation sequence, coordinated activity must occur from the single channel to the entire myocardial syncytium. Thus, sophisticated computational algorithms have been developed to investigate cardiac EP at the level of ion channels, cardiomyocytes, multicellular tissues, and the whole heart. Although understanding of each functional level will ultimately be important to thoroughly understand mechanisms of physiology and disease, cardiac arrhythmias are expressly the product of cardiac tissue—containing enough cardiomyocytes to sustain a reentrant loop of activation. In addition, several properties of cardiac cellular EP, that are critical for arrhythmogenesis, are significantly altered by cell-to-cell coupling. However, relevant human cardiac EP data, upon which to develop or validate models at all scales, has been lacking. Thus, over several years, we have developed a paradigm for multiscale human heart physiology investigation and have recovered and studied over 300 human hearts. We have generated a rich experimental dataset, from which we better understand mechanisms of arrhythmia in human and can improve models of human cardiac EP. In addition, in collaboration with computational physiologists, we are developing a database for the deposition of human heart experimental data, including thorough experimental documentation. We anticipate that accessibility to this human heart dataset will further human EP computational investigations, as well as encourage greater data transparency within the field of cardiac EP. PMID:25362174

  11. Effects of Heterogeneous Diffuse Fibrosis on Arrhythmia Dynamics and Mechanism

    NASA Astrophysics Data System (ADS)

    Kazbanov, Ivan V.; Ten Tusscher, Kirsten H. W. J.; Panfilov, Alexander V.

    2016-02-01

    Myocardial fibrosis is an important risk factor for cardiac arrhythmias. Previous experimental and numerical studies have shown that the texture and spatial distribution of fibrosis may play an important role in arrhythmia onset. Here, we investigate how spatial heterogeneity of fibrosis affects arrhythmia onset using numerical methods. We generate various tissue textures that differ by the mean amount of fibrosis, the degree of heterogeneity and the characteristic size of heterogeneity. We study the onset of arrhythmias using a burst pacing protocol. We confirm that spatial heterogeneity of fibrosis increases the probability of arrhythmia induction. This effect is more pronounced with the increase of both the spatial size and the degree of heterogeneity. The induced arrhythmias have a regular structure with the period being mostly determined by the maximal local fibrosis level. We perform ablations of the induced fibrillatory patterns to classify their type. We show that in fibrotic tissue fibrillation is usually of the mother rotor type but becomes of the multiple wavelet type with increase in tissue size. Overall, we conclude that the most important factor determining the formation and dynamics of arrhythmia in heterogeneous fibrotic tissue is the value of maximal local fibrosis.

  12. Cardiac Medications

    MedlinePlus

    ... Giving for Heart.org Media for Heart.org Arrhythmia About Arrhythmia Why Arrhythmia Matters Understand Your Risk for Arrhythmia Symptoms, Diagnosis & Monitoring of Arrhythmia Prevention & Treatment of ...

  13. Iron does not cause arrhythmias in the guinea pig model of transfusional iron overload.

    PubMed

    Kaiser, Lana; Davis, John; Patterson, Jon; Boyd, Ryan F; Olivier, N Bari; Bohart, George; Schwartz, Kenneth A

    2007-08-01

    Cardiac events, including heart failure and arrhythmias, are the leading cause of death in patients with beta thalassemia. Although cardiac arrhythmias in humans are believed to result from iron overload, excluding confounding factors in the human population is difficult. The goal of the current study was to determine whether cardiac arrhythmias occurred in the guinea pig model of secondary iron overload. Electrocardiograms were recorded by using surgically implanted telemetry devices in guinea pigs loaded intraperitoneally with iron dextran (test animals) or dextran alone (controls). Loading occurred over approximately 6 wk. Electrocardiograms were recorded for 1 wk prior to loading, throughout loading, and for approximately 4 wk after loading was complete. Cardiac and liver iron concentrations were significantly increased in the iron-loaded animals compared with controls and were in the range of those reported for humans with thalassemia. Arrhythmias were rare in both iron-loaded and control guinea pigs. No life-threatening arrhythmias were detected in either group. These data suggest that iron alone may be insufficient to cause cardiac arrhythmias in the iron-loaded guinea pig model and that arrhythmias detected in human patients with iron overload may be the result of a complex interplay of factors.

  14. Addictive drugs, arrhythmias, and cardiac inward rectifiers.

    PubMed

    Bébarová, Markéta; Hořáková, Zuzana; Kula, Roman

    2016-06-14

    In many addictive drugs including alcohol and nicotine, proarrhythmic effects were reported. This review provides an overview of the current knowledge in this field (with a focus on the inward rectifier potassium currents) to promote the lacking data and appeal for their completion, thus, to improve understanding of the proarrhythmic potential of addictive drugs.

  15. Recording signs of deterioration in acute patients: The documentation of vital signs within electronic health records in patients who suffered in-hospital cardiac arrest.

    PubMed

    Stevenson, Jean E; Israelsson, Johan; Nilsson, Gunilla C; Petersson, Göran I; Bath, Peter A

    2016-03-01

    Vital sign documentation is crucial to detecting patient deterioration. Little is known about the documentation of vital signs in electronic health records. This study aimed to examine documentation of vital signs in electronic health records. We examined the vital signs documented in the electronic health records of patients who had suffered an in-hospital cardiac arrest and on whom cardiopulmonary resuscitation was attempted between 2007 and 2011 (n = 228), in a 372-bed district general hospital. We assessed the completeness of vital sign data compared to VitalPAC™ Early Warning Score and the location of vital signs within the electronic health records. There was a noticeable lack of completeness of vital signs. Vital signs were fragmented through various sections of the electronic health records. The study identified serious shortfalls in the representation of vital signs in the electronic health records, with consequential threats to patient safety.

  16. Discriminative sparse coding of ECG during ventricular arrhythmias using LC-K-SVD approach.

    PubMed

    Kalaji, I; Balasundaram, K; Umapathy, K

    2015-01-01

    Ventricular tachycardia (VT) and ventricular fibrillation (VF) are two major types of ventricular arrhythmias that results due to abnormalities in the electrical activation in the ventricles of the heart. VF is the lethal of the two arrhythmias, which may lead to sudden cardiac death. The treatment options for the two arrhythmias are different. Therefore, detection and characterization of the two arrhythmias is critical to choose appropriate therapy options. Due to the time-varying nature of the signal content during cardiac arrhythmias, modeling and extracting information from them using time and frequency localized functions would be ideal. To this effect, in this work, we perform discriminative sparse coding of the ECG during ventricular arrhythmia with hybrid time-frequency dictionaries using the recently introduced Label consistent K-SVD (LC-K-SVD) approach. Using 944 segments of ventricular arrhythmias extracted from 23 patients in the Malignant Ventricular Ectopy and Creighton University Tachy-Arrhythmia databases, an overall classification accuracy of 71.55% was attained with a hybrid dictionary of Gabor and symlet4 atoms. In comparison, for the same database and non-trained dictionary (i.e the original dictionary) the classification accuracy was found to be 62.71%. In addition, the modeling error using the trained dictionary from LC-K-SVD approach was found to be significantly lower to the one using the non-trained dictionary.

  17. Who Is at Risk for Arrhythmia?

    MedlinePlus

    ... on Twitter. Who Is at Risk for an Arrhythmia? Arrhythmias are very common in older adults. Atrial fibrillation (a common type of arrhythmia that can cause problems) affects millions of people, ...

  18. Arrhythmias in newborn thoroughbred foals.

    PubMed

    Yamamoto, K; Yasuda, J; Too, K

    1992-05-01

    Foetal electrocardiograms (ECG) were obtained from 39 of 50 Thoroughbred foaling mares close to delivery. The 50 newborn foals were studied electrocardiographically during their adaptive period, immediately after birth. In 48 foals there were paroxysmal arrhythmias or mixed arrhythmias. The most common arrhythmias were sinus arrhythmias including wandering pacemaker (32/50) and atrial premature contraction (30/50). The others observed were atrial fibrillation (15/50), ventricular premature contraction (10/50), partial atrioventricular block (7/50), ventricular tachycardia (4/50), atrial tachycardia (3/50) and idioventricular rhythm (1/50). The duration of the arrhythmias was approximately 5 min, and in all cases the arrhythmia disappeared within 15 min of birth. From foetal ECG recordings, no indication of the likelihood of neonatal arrhythmias was detected. With the exception of 2 cases, all foals have continued to grow and develop normally. These arrhythmias are considered normal physiological processes in newborn Thoroughbred foals during the adaptive period to extra-uterine life. High vagal tone and hypoxaemia at birth are probably the main contributing factors.

  19. Sudden Cardiac Death As a Result of Neglected Hypopituitarism

    PubMed Central

    Hajsheikholeslami, Farhad; Yazdani, Shahrooz

    2013-01-01

    Cardiac involvement infrequently occurs in hypopituitarism, and lethal cardiac arrhythmias are rarely reported. We present a middle age female who died as a consequence of refractory ventricular arrhythmia whose medical history and previous laboratory investigation were consistent with hypopituitarism. We conclude that hypopituitarism may lead to electrocardiographic changes and malignant ventricular arrhythmia and should be included in laboratory investigation and differential diagnosis of patients presenting with long QT syndrome PMID:23825983

  20. Ventricular arrhythmia incidence in the rat is reduced by naloxone.

    PubMed

    Pugsley, M K; Hayes, E S; Wang, W Q; Walker, M J A

    2015-07-01

    This study characterized the antiarrhythmic effects of the opioid receptor antagonist naloxone in rats subject to electrically induced and ischemic arrhythmias. Naloxone (2, 8 and 32 μmol/kg/min) was examined on heart rate, blood pressure, and the electrocardiogram (EKG) as well as for effectiveness against arrhythmias produced by occlusion of the left anterior descending coronary artery or electrical stimulation of the left ventricle. Naloxone reduced blood pressure at the highest dose tested while heart rate was dose-dependently reduced. Naloxone dose-dependently prolonged the P-R and QRS intervals and increased the RSh amplitude indicative of effects on cardiac sodium (Na) channels. Naloxone prolonged the Q-T interval suggesting a delay in repolarization. Naloxone effects were comparable to the comparator quinidine. Naloxone (32 μmol/kg/min) reduced ventricular fibrillation (VF) incidence to 38% (from 100% in controls). This same dose significantly increased the threshold for induction of ventricular fibrillation (VFt), prolonged the effective refractory period (ERP) and reduced the maximal following frequency (MFF). The patterns of ECG changes, reduction in ischemic arrhythmia (VF) incidence and changes in electrically induced arrhythmia parameters at high doses of naloxone suggest that it directly blocks cardiac Na and potassium (K) ion channels.

  1. Stabilisation of medically refractory ventricular arrhythmia by intra-aortic balloon counterpulsation

    PubMed Central

    Fotopoulos, G; Mason, M; Walker, S; Jepson, N; Patel, D; Mitchell, A; Ilsley, C; Paul, V

    1999-01-01

    OBJECTIVE—To review the efficacy of intra-aortic balloon counterpulsation (IABCP) in medically refractory ventricular arrhythmia.
DESIGN—Retrospective analysis of the outcome of patients with ventricular arrhythmia treated with IABCP after transfer between 1992 and 1997.
SETTING—Tertiary cardiac referral centre.
PATIENTS—21 patients (mean age 58 years) who underwent IABCP for control of ventricular arrhythmia. All had significant left ventricular impairment (mean ejection fraction 28.6%); 18 had coronary artery disease.
RESULTS—Before IABCP, 10 patients had incessant monomorphic ventricular tachycardia and 11 had paroxysmal ventricular tachycardia and/or ventricular fibrillation (VT/VF). IABCP resulted in suppression of ventricular arrhythmia in 18 patients, of whom 13 were weaned from IABCP. After stabilisation of ventricular arrhythmia, 10 patients were maintained on medical treatment alone and one underwent endocardial resection. IABCP was maintained until cardiac transplantation in five patients. One patient had a fatal arrest before discharge and one died from progressive heart failure. IABCP failed to control ventricular arrhythmia in three patients and was subsequently discontinued. A cardiac assist device was employed in one of these until cardiac transplantation; the other two were eventually stabilised on medical treatment. Nineteen patients were discharged from hospital. Overall survival was 95% at mean follow up of 25.7 months.
CONCLUSIONS—IABCP can be an effective means of controlling refractory ventricular arrhythmia, allowing time for the institution of more definitive treatment.


Keywords: ventricular arrhythmia; intra-aortic balloon counterpulsation PMID:10377318

  2. Low vagally-mediated heart rate variability and increased susceptibility to ventricular arrhythmias in rats bred for high anxiety.

    PubMed

    Carnevali, Luca; Trombini, Mimosa; Graiani, Gallia; Madeddu, Denise; Quaini, Federico; Landgraf, Rainer; Neumann, Inga D; Nalivaiko, Eugene; Sgoifo, Andrea

    2014-04-10

    In humans, there is a documented association between anxiety disorders and cardiovascular disease. Putative underlying mechanisms may include an impairment of the autonomic nervous system control of cardiac function. The primary objective of the present study was to characterize cardiac autonomic modulation and susceptibility to arrhythmias in genetic lines of rats that differ largely in their anxiety level. To reach this goal, electrocardiographic recordings were performed in high-anxiety behavior (HAB, n=10) and low-anxiety behavior (LAB, n=10) rats at rest, during stressful stimuli and under autonomic pharmacological manipulations, and analyzed by means of time- and frequency-domain indexes of heart rate variability. During resting conditions, HAB rats displayed a reduced heart rate variability, mostly in terms of lower parasympathetic (vagal) modulation compared to LAB rats. In HAB rats, this relatively low cardiac vagal control was associated with smaller heart rate responsiveness to acute stressors compared to LAB counterparts. In addition, beta-adrenergic pharmacological stimulation induced a larger incidence of ventricular tachyarrhythmias in HABs compared to LABs. At sacrifice, a moderate increase in heart-body weight ratio was observed in HAB rats. We conclude that high levels of anxiety-related behavior in rats are associated with signs of i) impaired autonomic modulation of heart rate (low vagally-mediated heart rate variability), ii) poor adaptive heart rate responsiveness to stressful stimuli, iii) increased arrhythmia susceptibility, and iv) cardiac hypertrophy. These results highlight the utility of the HAB/LAB model for investigating the mechanistic basis of the comorbidity between anxiety disorders and cardiovascular disease.

  3. [Prevalence of supraventricular tachycardia and tachyarrhythmias in resuscitated cardiac arrest].

    PubMed

    Brembilla-Perrot, B; Marcon, O; Blangy, H; Terrier de la Chaise, A; Louis, P; Sadoul, N; Claudon, O; Nippert, M; Popovic, B; Belhakem, H

    2006-01-01

    Supraventricular arrhythmias are considered to be benign when the ventricular rate is slowed and treated by anticoagulants. The aim of this study was to determine the possible influence of these arrhythmias in resuscitated cardiac arrest. Between 1980 and 2002, 151 patients were admitted after a cardiac arrest. Supraventricular arrhythrmias were identified as a possible cause of the cardiac arrest in 21 patients. They underwent echocardiography, exercise stress test, Holter ECG monitoring , coronary angiography and electrophysiological investigation. After these investigations, three patients had a malignant form of the Wolff-Parkinson-White syndrome, two were asymptomatic and, in the third patient, ventricular fibrillation was induced by treatment with diltiazem. In 8 patients, a rapid supraventricular arrhythmia was considered to be the cause of cardiac arrest by cardiogenic shock; 2 patients had hypertrophic cardiomyopathy, 5 had severe dilated cardiomyopathy which regressed in one patient. In ten patients, cardiac arrest due to ventricular tachycardia or fibrillation was provoked by a rapid (> 220 beats/min) supraventricular arrhythmia; two patients had no apparent underlying cardiac pathology. In the others, myocardial ischaemia or acute cardiac failure were considered to be the cause of the cardiac arrest. The authors conclude that rapid supraventricular arrhythmias may cause cardiac arrest either by cardiogenic shock or degenerescence to ventricular tachycardia or fibrillation. Usually, this event occurs in patients with severe cardiac disease but it may occur in subjects without cardiac disease or by an arrhythmia-induced cardiomyopathy.

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

    PubMed

    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.

  5. Ventricular repolarization markers for predicting malignant arrhythmias in clinical practice

    PubMed Central

    Castro-Torres, Yaniel; Carmona-Puerta, Raimundo; Katholi, Richard E

    2015-01-01

    Malignant cardiac arrhythmias which result in sudden cardiac death may be present in individuals apparently healthy or be associated with other medical conditions. The way to predict their appearance represents a challenge for the medical community due to the tragic outcomes in most cases. In the last two decades some ventricular repolarization (VR) markers have been found to be useful to predict malignant cardiac arrhythmias in several clinical conditions. The corrected QT, QT dispersion, Tpeak-Tend, Tpeak-Tend dispersion and Tp-e/QT have been studied and implemented in clinical practice for this purpose. These markers are obtained from 12 lead surface electrocardiogram. In this review we discuss how these markers have demonstrated to be effective to predict malignant arrhythmias in medical conditions such as long and short QT syndromes, Brugada syndrome, early repolarization syndrome, acute myocardial ischemia, heart failure, hypertension, diabetes mellitus, obesity and highly trained athletes. Also the main pathophysiological mechanisms that explain the arrhythmogenic predisposition in these diseases and the basis for the VR markers are discussed. However, the same results have not been found in all conditions. Further studies are needed to reach a global consensus in order to incorporate these VR parameters in risk stratification of these patients. PMID:26301231

  6. [Ryanodine receptor, calcium leak and arrhythmias].

    PubMed

    Rueda, Angélica; de Alba-Aguayo, David R; Valdivia, Héctor H

    2014-01-01

    The participation of the ionic Ca(2+) release channel/ryanodine receptor in cardiac excitation-contraction coupling is well known since the late '80s, when various seminal papers communicated its purification for the first time and its identity with the "foot" structures located at the terminal cisternae of the sarcoplasmic reticulum. In addition to its main role as the Ca(2+) channel responsible for the transient Ca(2+) increase that activates the contractile machinery of the cardiomyocytes, the ryanodine receptor releases Ca(2+) during the relaxation phase of the cardiac cycle, giving rise to a diastolic Ca(2+) leak. In normal physiological conditions, diastolic Ca(2+) leak regulates the proper level of luminal Ca(2+), but in pathological conditions it participates in the generation of both, acquired and hereditary arrhythmias. Very recently, several groups have focused their efforts into the development of pharmacological tools to control the altered diastolic Ca(2+) leak via ryanodine receptors. In this review, we focus our interest on describing the participation of cardiac ryanodine receptor in the diastolic Ca(2+) leak under physiological or pathological conditions and also on the therapeutic approaches to control its undesired exacerbated activity during diastole.

  7. Atrial flutter a manifestation of cardiac tamponade.

    PubMed

    Pabón, Guillermo Mora; Ramírez, John A

    2012-04-01

    Atrial flutter (AFL) is a common arrhythmia that is associated with postpericardiotomy and pericarditis. The relationship of AFL with tamponade has rarely been reported. A case of AFL with acute pericarditis and cardiac tamponade is thus presented here.

  8. Mechanisms of Sudden Cardiac Death: Oxidants and Metabolism

    PubMed Central

    Yang, Kai-Chien; Kyle, John W.; Makielski, Jonathan C.; Dudley, Samuel C.

    2015-01-01

    Ventricular arrhythmia is the leading cause of sudden cardiac death (SCD). Deranged cardiac metabolism and abnormal redox state during cardiac diseases foment arrhythmogenic substrates through direct or indirect modulation of cardiac ion channel/transporter function. This review presents current evidence on the mechanisms linking metabolic derangement and excessive oxidative stress to ion channel/transporter dysfunction that predisposes to ventricular arrhythmias and SCD. As conventional anti-arrhythmic agents aiming at ion channels have proven challenging to use, targeting arrhythmogenic metabolic changes and redox imbalance may provide novel therapeutics to treat or prevent life-threatening arrhythmias and SCD. PMID:26044249

  9. Nonlinear-dynamical arrhythmia control in humans

    PubMed Central

    Christini, David J.; Stein, Kenneth M.; Markowitz, Steven M.; Mittal, Suneet; Slotwiner, David J.; Scheiner, Marc A.; Iwai, Sei; Lerman, Bruce B.

    2001-01-01

    Nonlinear-dynamical control techniques, also known as chaos control, have been used with great success to control a wide range of physical systems. Such techniques have been used to control the behavior of in vitro excitable biological tissue, suggesting their potential for clinical utility. However, the feasibility of using such techniques to control physiological processes has not been demonstrated in humans. Here we show that nonlinear-dynamical control can modulate human cardiac electrophysiological dynamics by rapidly stabilizing an unstable target rhythm. Specifically, in 52/54 control attempts in five patients, we successfully terminated pacing-induced period-2 atrioventricular-nodal conduction alternans by stabilizing the underlying unstable steady-state conduction. This proof-of-concept demonstration shows that nonlinear-dynamical control techniques are clinically feasible and provides a foundation for developing such techniques for more complex forms of clinical arrhythmia. PMID:11320216

  10. Nonlinear-dynamical arrhythmia control in humans.

    PubMed

    Christini, D J; Stein, K M; Markowitz, S M; Mittal, S; Slotwiner, D J; Scheiner, M A; Iwai, S; Lerman, B B

    2001-05-08

    Nonlinear-dynamical control techniques, also known as chaos control, have been used with great success to control a wide range of physical systems. Such techniques have been used to control the behavior of in vitro excitable biological tissue, suggesting their potential for clinical utility. However, the feasibility of using such techniques to control physiological processes has not been demonstrated in humans. Here we show that nonlinear-dynamical control can modulate human cardiac electrophysiological dynamics by rapidly stabilizing an unstable target rhythm. Specifically, in 52/54 control attempts in five patients, we successfully terminated pacing-induced period-2 atrioventricular-nodal conduction alternans by stabilizing the underlying unstable steady-state conduction. This proof-of-concept demonstration shows that nonlinear-dynamical control techniques are clinically feasible and provides a foundation for developing such techniques for more complex forms of clinical arrhythmia.

  11. Cardiac spinal deafferentation reduces the susceptibility to sustained ventricular tachycardia in conscious rats

    PubMed Central

    Lujan, Heidi L.; Krishnan, Sandhya

    2011-01-01

    The response to myocardial ischemia is complex and involves the cardio-cardiac sympathetic reflex. Specifically, cardiac spinal (sympathetic) afferents are excited by ischemic metabolites and elicit an excitatory sympathetic reflex, which plays a major role in the genesis of ventricular arrhythmias. For example, brief myocardial ischemia leads to ATP release, which activates cardiac spinal afferents through stimulation of P2 receptors. Clinical work with patients and preclinical work with animals document that disruption of this reflex protects against ischemia-induced ventricular arrhythmias. However, the role of afferent signals in the initiation of sustained ventricular tachycardia has not been investigated. Therefore, we tested the hypothesis that cardiac spinal deafferentation reduces the susceptibility to sustained ventricular tachycardia in adult (12–15 wk of age), conscious, male Sprague-Dawley rats. To test this hypothesis, the susceptibility to ventricular tachyarrhythmias produced by occlusion of the left main coronary artery was determined in two groups of conscious rats: 1) deafferentation (bilateral excision of the T1-T5 dorsal root ganglia) and 2) control (sham deafferentation). The ventricular arrhythmia threshold (VAT) was defined as the time from coronary occlusion to sustained ventricular tachycardia resulting in a reduction in arterial pressure. Results document a significantly higher VAT in the deafferentation group (7.0 ± 0.7 min) relative to control (4.3 ± 0.3 min) rats. The decreased susceptibility to tachyarrhythmias with deafferentation was associated with a reduced cardiac metabolic demand (lower rate-pressure product and ST segment elevation) during ischemia. PMID:21677267

  12. The effect of fiberoptic bronchoscopy on cardiac rhythm.

    PubMed

    Shrader, D L; Lakshminarayan, S

    1978-06-01

    Cardiac rhythm was monitored in 70 patients prior to, during, and following fiberoptic bronchoscopic procedures. Minor abnormalities in rhythm were frequent. Major cardiac arrhythmias occurred in 11% (8/70) of the patients during the bronchoscopic procedure. All arrhythmias were self-limited and had no hemodynamic consequence. Patients with evidence of coronary arterial disease, chronic obstructive pulmonary disease, or previously known premature ventricular contractions were at no higher risk for developing major arrhythmias. Hypoxemia (arterial oxygen pressure less than 60 mm Hg) at the end of the procedure correlated significantly with the development of new major arrhythmias.

  13. Channelopathies - Emerging Trends in The Management of Inherited Arrhythmias

    PubMed Central

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

    2016-01-01

    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 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. PMID:25852242

  14. An ECG analysis interactive training system for understanding arrhythmias.

    PubMed

    Lessard, Yvon; Sinteff, Jean-Paul; Siregar, Pridi; Julen, Nathalie; Hannouche, Frédéric; Rio, Stéphane; Le Beux, Pierre

    2009-01-01

    The ECG remains a daily diagnostic tool for the detection of numerous cardiovascular diseases. Our goal was to use a computerized qualitative model (QM) of heart in order to build cases of simple arrhythmias dedicated to initial and more advanced medical teaching. The original QM is able to generate videograms of many cardiac disturbances. A Flash player is used to view ECG, synchronous Lewis diagram and chromatic 2D cardiac animation of a specific case. OAAT is a standardized 18 yes/no answers questionnaire which allows the learner to diagnose five main types of arrhythmias that can be compared with normal sinus rhythm (NSR) analysis. This new tool has been recently used by medical students during practical sessions. Based on medical reasoning learning on NSR video and upon trying to recognize an abnormal cardiac rhythm, all users can reach the 100% winning score since they can perform as many attempts as they like. We believe that unlimited case review with questionnaire answering, ECG and Lewis diagram replay and step-by-step visualization of the abnormal propagation of the cardiac impulse on the 2D heart videos are a highly efficient means to help students understand even complex arrhythmic mechanisms.

  15. A single exposure to particulate or gaseous air pollution increases the risk of aconitine-induced cardiac arrythmia in hypertensive rats

    EPA Science Inventory

    Epidemiological studies demonstrate a significant association between arrhythmias and air pollution exposure. Sensitivity to aconitine-induced arrhythmia has been used repeatedly to examine the factors that increase the risk of such cardiac electrical dysfunction. In this study, ...

  16. Diesel exhaust worsens cardiac conduction instability in dobutamine-challenged spontaneously hypertensive rats

    EPA Science Inventory

    This study demonstrated that diesel exhaust worsened arrhythmia and cardiac function during dobutamine (simulated exercise) challenge in normotensive and hypertensive rats. The data presented here are a mathematically-derived indicator of cardiac risk, which can be used for risk ...

  17. Sudden Arrhythmia Death Syndromes (SADS) Foundation

    MedlinePlus

    ... Family Seminar 04/29/17 Update on Inherited Arrhythmias: Recent Advancements in Therapies and Diagnosis--From 8: ... Legal Notice Privacy Policy COPYRIGHT ©2011-2016 Sudden Arrhythmia Death Syndromes Foundation 4527 South 2300 East, Suite ...

  18. Cardioverter-Defibrillator: A Treatment for Arrhythmia

    MedlinePlus

    ... life-threatening arrhythmias, including ventricular tachycardia and ventricular fibrillation.Ventricular tachycardia (say: "tack-ee-card-ee-ya") ... type of arrhythmia can be life threatening.Ventricular fibrillation is when the bottom chambers of your heart ( ...

  19. Induced pluripotent stem cell-derived cardiomyocytes: boutique science or valuable arrhythmia model?

    PubMed

    Knollmann, Björn C

    2013-03-15

    This article reviews the strengths and limitations of induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM) as models of cardiac arrhythmias. Specifically, the article attempts to answer the following questions: Which clinical arrhythmias can be modeled by iPSC-CM? How well can iPSC-CM model adult ventricular myocytes? What are the strengths and limitations of published iPSC-CM arrhythmia models? What new mechanistic insight has been gained? What is the evidence that would support using iPSC-CM to personalize antiarrhythmic drug therapy? The review also discusses the pros and cons of using the iPSC-CM technology for modeling specific genetic arrhythmia disorders, such as long QT syndrome, Brugada Syndrome, or Catecholaminergic Polymorphic Ventricular Tachycardia.

  20. [Treatment of bradycardiac arrhythmias with depot-orciprenaline (author's transl)].

    PubMed

    So, C S; Volger, E

    1976-07-02

    24 patients with bradycardiac arrhythmias of various origin were treated with a new depot preparation of orciprenaline. The special galenical preparation guarantees effectiveness ofr 8-10 hours. In 21 patients (87%), therefore, one dragee morning and evening was sufficient to obtain a mean rise in frequency of 57%. The preparation had to be discontinued in 3 cases because of side effects such as increase in ventricular extrasystoles, anginal complaints and critical rise of blood pressure in hypertension. Because of its trouble-free administration in a depot form the preparation not only offers a practical advantage over the short-acting commercial preparations, but also shows a reliable efficacy. It can therefore be given under regular supervision in all forms of bradycardiac arrhythmias with stable ventricular frequency and satisfactory cardiac output.

  1. A Novel Alpha Cardiac Actin (ACTC1) Mutation Mapping to a Domain in Close Contact with Myosin Heavy Chain Leads to a Variety of Congenital Heart Defects, Arrhythmia and Possibly Midline Defects

    PubMed Central

    Augière, Céline; Mégy, Simon; El Malti, Rajae; Boland, Anne; El Zein, Loubna; Verrier, Bernard; Mégarbané, André; Deleuze, Jean-François; Bouvagnet, Patrice

    2015-01-01

    Background A Lebanese Maronite family presented with 13 relatives affected by various congenital heart defects (mainly atrial septal defects), conduction tissue anomalies and midline defects. No mutations were found in GATA4 and NKX2-5. Methods and Results A set of 399 poly(AC) markers was used to perform a linkage analysis which peaked at a 2.98 lod score on the long arm of chromosome 15. The haplotype analysis delineated a 7.7 meganucleotides genomic interval which included the alpha-cardiac actin gene (ACTC1) among 36 other protein coding genes. A heterozygous missense mutation was found (c.251T>C, p.(Met84Thr)) in the ACTC1 gene which changed a methionine residue conserved up to yeast. This mutation was absent from 1000 genomes and exome variant server database but segregated perfectly in this family with the affection status. This mutation and 2 other ACTC1 mutations (p.(Glu101Lys) and p.(Met125Val)) which result also in congenital heart defects are located in a region in close apposition to a myosin heavy chain head region by contrast to 3 other alpha-cardiac actin mutations (p.(Ala297Ser),p.(Asp313His) and p.(Arg314His)) which result in diverse cardiomyopathies and are located in a totally different interaction surface. Conclusions Alpha-cardiac actin mutations lead to congenital heart defects, cardiomyopathies and eventually midline defects. The consequence of an ACTC1 mutation may in part be dependent on the interaction surface between actin and myosin. PMID:26061005

  2. Atrial Arrhythmias in Astronauts - Summary of a NASA Summit

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

    Background and Problem Definition: To evaluate NASA s current standards and practices related to atrial arrhythmias in astronauts, Space Medicine s Advanced Projects Section at the Johnson Space Center was tasked with organizing a summit to discuss the approach to atrial arrhythmias in the astronaut cohort. Since 1959, 11 cases of atrial fibrillation, atrial flutter, or supraventricular tachycardia have been recorded among active corps crewmembers. Most of the cases were paroxysmal, although a few were sustained. While most of the affected crewmembers were asymptomatic, those slated for long-duration space flight underwent radiofrequency ablation treatment to prevent further episodes of the arrhythmia. The summit was convened to solicit expert opinion on screening, diagnosis, and treatment options, to identify gaps in knowledge, and to propose relevant research initiatives. Summit Meeting Objectives: The Atrial Arrhythmia Summit brought together a panel of six cardiologists, including nationally and internationally renowned leaders in cardiac electrophysiology, exercise physiology, and space flight cardiovascular physiology. The primary objectives of the summit discussions were to evaluate cases of atrial arrhythmia in the astronaut population, to understand the factors that may predispose an individual to this condition, to understand NASA s current capabilities for screening, diagnosis, and treatment, to discuss the risks associated with treatment of crewmembers assigned to long-duration missions or extravehicular activities, and to discuss recommendations for prevention or management of future cases. Summary of Recommendations: The summit panel s recommendations were grouped into seven categories: Epidemiology, Screening, Standards and Selection, Treatment of Atrial Fibrillation Manifesting Preflight, Atrial Fibrillation during Flight, Prevention of Atrial Fibrillation, and Future Research

  3. Return of Viable Cardiac Function After Sonographic Cardiac Standstill in Pediatric Cardiac Arrest.

    PubMed

    Steffen, Katherine; Thompson, W Reid; Pustavoitau, Aliaksei; Su, Erik

    2017-01-01

    Sonographic cardiac standstill during adult cardiac arrest is associated with failure to get return to spontaneous circulation. This report documents 3 children whose cardiac function returned after standstill with extracorporeal membranous oxygenation. Sonographic cardiac standstill may not predict cardiac death in children.

  4. Method and apparatus for the guided ablative therapy of fast ventricular arrhythmia

    NASA Technical Reports Server (NTRS)

    Cohen, Richard J. (Inventor); Barley, Maya (Inventor)

    2010-01-01

    Method and apparatus for guiding ablative therapy of abnormal biological electrical excitation. The excitation from the previous excitatory wave is significant at the beginning of the next excitation. In particular, it is designed for treatment of fast cardiac arrhythmias. Electrical signals are acquired from recording electrodes, and an inverse dipole method is used to identify the site of origin of an arrhythmia. The location of the tip of an ablation catheter is similarly localized from signals acquired from the recording electrodes while electrical pacing energy is delivered to the tip of the catheter close to or in contact with the cardiac tissue. The catheter tip is then guided to the site of origin of the arrhythmia, and ablative radio frequency energy is delivered to its tip to ablate the site.

  5. The Alberta Cardiac Access Collaborative: improving the cardiac patient journey.

    PubMed

    Blackadar, Robyn; Houle, Mishaela

    2009-01-01

    The Alberta Cardiac Access Collaborative (ACAC) is a joint initiative of Alberta's health system to improve access to adult cardiac services across the patient journey. ACAC has created new care delivery models and implemented best practices across Alberta in four streams across the continuum: heart attack, patient navigation, heart failure and arrhythmia. Emergency medical providers, nurses, primary care physicians, hospitals, cardiac specialists and clinicians are all working together to integrate services, bridge jurisdictions and geography with one aim--improving the patient journey for adults in need of cardiac care.

  6. Sudden cardiac death secondary to antidepressant and antipsychotic drugs.

    PubMed

    Sicouri, Serge; Antzelevitch, Charles

    2008-03-01

    A number of antipsychotic and antidepressant drugs are known to increase the risk of ventricular arrhythmias and sudden cardiac death. Based largely on a concern over QT prolongation and the development of life-threatening arrhythmias, a number of antipsychotic drugs have been temporarily or permanently withdrawn from the market or their use restricted. Some antidepressants and antipsychotics have been linked to QT prolongation and the development of Torsade de pointes arrhythmias, whereas others have been associated with a Brugada syndrome phenotype and the development of polymorphic ventricular arrhythmias. This review examines the mechanisms and predisposing factors underlying the development of cardiac arrhythmias, and sudden cardiac death, associated with antidepressant and antipsychotic drugs in clinical use.

  7. Melanocyte-like cells in the heart and pulmonary veins contribute to atrial arrhythmia triggers

    PubMed Central

    Levin, Mark D.; Lu, Min Min; Petrenko, Nataliya B.; Hawkins, Brian J.; Gupta, Tara H.; Lang, Deborah; Buckley, Peter T.; Jochems, Jeanine; Liu, Fang; Spurney, Christopher F.; Yuan, Li J.; Jacobson, Jason T.; Brown, Christopher B.; Huang, Li; Beermann, Friedrich; Margulies, Kenneth B.; Madesh, Muniswamy; Eberwine, James H.; Epstein, Jonathan A.; Patel, Vickas V.

    2009-01-01

    Atrial fibrillation is the most common clinical cardiac arrhythmia. It is often initiated by ectopic beats arising from the pulmonary veins and atrium, but the source and mechanism of these beats remains unclear. The melanin synthesis enzyme dopachrome tautomerase (DCT) is involved in intracellular calcium and reactive species regulation in melanocytes. Given that dysregulation of intracellular calcium and reactive species has been described in patients with atrial fibrillation, we investigated the role of DCT in this process. Here, we characterize a unique DCT-expressing cell population within murine and human hearts that populated the pulmonary veins, atria, and atrioventricular canal. Expression profiling demonstrated that this population expressed adrenergic and muscarinic receptors and displayed transcriptional profiles distinct from dermal melanocytes. Adult mice lacking DCT displayed normal cardiac development but an increased susceptibility to atrial arrhythmias. Cultured primary cardiac melanocyte-like cells were excitable, and those lacking DCT displayed prolonged repolarization with early afterdepolarizations. Furthermore, mice with mutations in the tyrosine kinase receptor Kit lacked cardiac melanocyte-like cells and did not develop atrial arrhythmias in the absence of DCT. These data suggest that dysfunction of melanocyte-like cells in the atrium and pulmonary veins may contribute to atrial arrhythmias. PMID:19855129

  8. Behavioral Inhibition, Heart Period, and Respiratory Sinus Arrhythmia: An Attachment Perspective.

    ERIC Educational Resources Information Center

    Stevenson-Hinde, Joan; Marshall, Peter J.

    1999-01-01

    Examined interrelations among behavioral inhibition (BI), cardiac activity, and attachment status in 4.5-year olds. Found that only Secure children showed predicted relationship between low BI and high heart period (HP) or respiratory sinus arrhythmia. Increases in HP from assessment during separation from mother to assessment three minutes after…

  9. Relationship of ventricular arrhythmias to the angiographically and scintigraphically estimated extent of ventricular damage late after myocardial infarction

    SciTech Connect

    Huikuri, H.V.; Korhonen, U.R.; Linnaluoto, M.K.; Takkunen, J.T.

    1987-03-01

    In order to study the quantitative relationship of ventricular arrhythmias to myocardial damage and ischemia, 61 patients with a previous myocardial infarction (at least 6 months previously) were studied by 24-hour ambulatory ECG monitoring, cardiac catheterization, and thallium-201 scintigraphy. Thirty-five patients (57%) had no ectopic beats or only infrequent, unifocal ones and 26 patients (43%) had complex ventricular arrhythmias. Left ventricular function was lower in the latter, but the number of diseased vessels did not differ in the two groups. The reduction of thallium activity in the infarct area was more marked in patients with complex arrhythmias. Multiple thallium defects were not more common in arrhythmia patients, however. These data support the view that complex ventricular arrhythmias are more closely related to the severity of ventricular damage than the presence of myocardial ischemia remote to the area of previous infarction.

  10. Cardiac Vagal Regulation and Early Peer Status

    ERIC Educational Resources Information Center

    Graziano, Paulo A.; Keane, Susan P.; Calkins, Susan D.

    2007-01-01

    A sample of 341 5 1/2-year-old children participating in an ongoing longitudinal study was the focus of a study on the relation between cardiac vagal regulation and peer status. To assess cardiac vagal regulation, resting measures of respiratory sinus arrhythmia (RSA) and RSA change (suppression) to 3 cognitively and emotionally challenging tasks…

  11. Diagnosis of traumatic cardiac contusion

    SciTech Connect

    Waxman, K.; Soliman, M.H.; Braunstein, P.; Formosa, P.; Cohen, A.J.; Matsuura, P.; Mason, G.R.

    1986-06-01

    Cardiac contusion following blunt chest trauma remains a diagnostic problem because of a lack of sensitive diagnostic tests. This study evaluated thallous chloride Tl 201 single-photon-emission computed tomography in a series of 48 patients following blunt chest trauma. Of the 48 patients, 23 had normal scans. None of these patients proved to have serious arrhythmias during three days of continuous monitoring. Of 25 patients with abnormal or ambiguous studies, five (20%) developed serious arrhythmias requiring therapy. Single-photon-emission computed tomography scanning thus was sensitive in indicating that group of patients at risk of serious arrhythmias, and may therefore prove to be a useful screening test to determine the need for hospitalization and arrhythmia monitoring following blunt chest trauma.

  12. Increased dispersion of refractoriness in the absence of QT prolongation in patients with mitral valve prolapse and ventricular arrhythmias.

    PubMed Central

    Tieleman, R. G.; Crijns, H. J.; Wiesfeld, A. C.; Posma, J.; Hamer, H. P.; Lie, K. I.

    1995-01-01

    BACKGROUND--The mechanism responsible for the reported high incidence of ventricular arrhythmias in mitral valve prolapse is not clear. Electrocardiographic studies show an increased occurrence of repolarisation abnormalities on the 12 lead surface electrocardiogram, indicating regional differences in ventricular recovery. The purpose of this study was to investigate whether dispersion of refractoriness was an arrhythmogenic mechanism. METHODS--QT dispersion was measured in 32 patients with echocardiographically documented mitral valve prolapse and ventricular arrhythmias on 24 hour Holter recordings. QT dispersion was defined as the difference between the maximum and minimum average QT interval in any of the 12 leads of the surface electrocardiogram. QT dispersion corrected for heart rate was calculated by Bazett's formula. The results were compared with the data from 32 matched controls without a history of cardiac disease. Patients taking drugs that influence the QT interval and patients with a QRS duration > 120 ms were excluded. RESULTS--QT dispersion was greater in patients with mitral valve prolapse than in matched controls (60 (20) v 39 (11 ms) respectively, P < or = 0.001) as was corrected QT (64 (20 ms) v 43 (12 ms) respectively, P < or = 0.001). There was no significant difference in minimum or maximum QT intervals between the two groups. CONCLUSIONS--QT dispersion on the 12 lead surface electrocardiogram was greater in patients with mitral valve prolapse with ventricular arrhythmias than in normal controls, but the maximum QT interval was not increased. The results accord with the hypothesis that regional shortening and lengthening of repolarisation times in patients with mitral valve prolapse may account for the increased dispersion of refractoriness. PMID:7888258

  13. Proposition of novel classification approach and features for improved real-time arrhythmia monitoring.

    PubMed

    Kim, Yoon Jae; Heo, Jeong; Park, Kwang Suk; Kim, Sungwan

    2016-08-01

    Arrhythmia refers to a group of conditions in which the heartbeat is irregular, fast, or slow due to abnormal electrical activity in the heart. Some types of arrhythmia such as ventricular fibrillation may result in cardiac arrest or death. Thus, arrhythmia detection becomes an important issue, and various studies have been conducted. Additionally, an arrhythmia detection algorithm for portable devices such as mobile phones has recently been developed because of increasing interest in e-health care. This paper proposes a novel classification approach and features, which are validated for improved real-time arrhythmia monitoring. The classification approach that was employed for arrhythmia detection is based on the concept of ensemble learning and the Taguchi method and has the advantage of being accurate and computationally efficient. The electrocardiography (ECG) data for arrhythmia detection was obtained from the MIT-BIH Arrhythmia Database (n=48). A novel feature, namely the heart rate variability calculated from 5s segments of ECG, which was not considered previously, was used. The novel classification approach and feature demonstrated arrhythmia detection accuracy of 89.13%. When the same data was classified using the conventional support vector machine (SVM), the obtained accuracy was 91.69%, 88.14%, and 88.74% for Gaussian, linear, and polynomial kernels, respectively. In terms of computation time, the proposed classifier was 5821.7 times faster than conventional SVM. In conclusion, the proposed classifier and feature showed performance comparable to those of previous studies, while the computational complexity and update interval were highly reduced.

  14. Cardiac Resynchronization Therapy (CRT)

    MedlinePlus

    ... Giving for Heart.org Media for Heart.org Arrhythmia About Arrhythmia Why Arrhythmia Matters Understand Your Risk for Arrhythmia Symptoms, Diagnosis & Monitoring of Arrhythmia Prevention & Treatment of ...

  15. A Case of Cardiac Amyloidosis Initially Misdiagnosed as Syndrome X

    PubMed Central

    Sohn, Hyung Rae; Song, Bong Gun; Jeong, Seong Yeon; Hong, Su-Min; Jung, Hyun Gul; Jung, Hye-Jin; Cho, Wook-Hyun; Choi, Suk-Koo

    2011-01-01

    Cardiac infiltration of amyloid fibril results in progressive cardiomyopathy with a grave prognosis and results in cardiac diseases such as congestive heart disease, cardiomyopathy, valvular heart disease, and arrhythmias. We present a rare case of cardiac amyloidosis initially misdiagnosed as syndrome X in which recurrent chest pain and progressive heart failure could be managed finally by heart transplantation.

  16. Relation of burden of myocardial fibrosis to malignant ventricular arrhythmias and outcomes in Fabry disease.

    PubMed

    Krämer, Johannes; Niemann, Markus; Störk, Stefan; Frantz, Stefan; Beer, Meinrad; Ertl, Georg; Wanner, Christoph; Weidemann, Frank

    2014-09-15

    The aim of this study was to investigate the impact of myocardial fibrosis in Fabry disease. Seventy-three patients with genetically confirmed Fabry disease were followed for 4.8 ± 2.4 years. In accordance with current guidelines, 57 patients received enzyme replacement therapy (ERT) after study inclusion, whereas 16 did not. At baseline and latest possible follow-up, myocardial fibrosis was assessed noninvasively by cardiac magnetic resonance, and biomarkers of collagen metabolism were determined. Holter electrocardiography and clinical follow-up at yearly intervals were used to monitor malignant ventricular arrhythmias (MVAs; nonsustained and sustained ventricular tachycardia and sudden cardiac death). In total, 48 patients (66%) showed fibrosis assessed by late enhancement (LE) at baseline, and 4 patients developed new LE during follow-up, 2 of them despite ERT. The 2 patients receiving ERT (1.4 ± 1.9% vs 2.5 ± 2.6%, p <0.001) and the patients not receiving ERT (0.5 ± 0.8% vs 0.7 ± 1.0%, p = 0.035) showed a progression of LE during follow-up. None of the patients displayed reductions of LE during follow-up. Collagen biomarkers were elevated in patients with and without LE but did not correlate with LE amount. Thirteen LE-positive patients at the baseline examination had documented MVAs (including 5 sudden cardiac deaths), whereas none of the patients without LE had MVAs. The yearly increase in fibrosis was 0.9 ± 0.6% in patients with MVAs and 0.2 ± 0.3% in patients without MVAs (p <0.001). Logistic multivariate regression analysis revealed that the annual increase in fibrosis during follow-up was the only independent predictor of MVAs. In conclusion, myocardial fibrosis in Fabry disease is progressive, apparently not modified by ERT, and a crucial outcome determinant.

  17. Novel Calmodulin (CALM2) Mutations Associated with Congenital Arrhythmia Susceptibility

    PubMed Central

    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

  18. Effect of fish oil on arrhythmias and mortality: systematic review

    PubMed Central

    León, Hernando; Shibata, Marcelo C; Sivakumaran, Soori; Dorgan, Marlene; Chatterley, Trish

    2008-01-01

    Objective To synthesise the literature on the effects of fish oil—docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA)—on mortality and arrhythmias and to explore dose response and formulation effects. Design Systematic review and meta-analysis. Data sources Medline, Embase, the Cochrane Library, PubMed, CINAHL, IPA, Web of Science, Scopus, Pascal, Allied and Complementary Medicine, Academic OneFile, ProQuest Dissertations and Theses, Evidence-Based Complementary Medicine, and LILACS. Studies reviewed Randomised controlled trials of fish oil as dietary supplements in humans. Data extraction The primary outcomes of interest were the arrhythmic end points of appropriate implantable cardiac defibrillator intervention and sudden cardiac death. The secondary outcomes were all cause mortality and death from cardiac causes. Subgroup analyses included the effect of formulations of EPA and DHA on death from cardiac causes and effects of fish oil in patients with coronary artery disease or myocardial infarction. Data synthesis 12 studies totalling 32 779 patients met the inclusion criteria. A neutral effect was reported in three studies (n=1148) for appropriate implantable cardiac defibrillator intervention (odds ratio 0.90, 95% confidence interval 0.55 to 1.46) and in six studies (n=31 111) for sudden cardiac death (0.81, 0.52 to 1.25). 11 studies (n=32 439 and n=32 519) provided data on the effects of fish oil on all cause mortality (0.92, 0.82 to 1.03) and a reduction in deaths from cardiac causes (0.80, 0.69 to 0.92). The dose-response relation for DHA and EPA on reduction in deaths from cardiac causes was not significant. Conclusions Fish oil supplementation was associated with a significant reduction in deaths from cardiac causes but had no effect on arrhythmias or all cause mortality. Evidence to recommend an optimal formulation of EPA or DHA to reduce these outcomes is insufficient. Fish oils are a heterogeneous product, and the optimal formulations

  19. Cardiac autonomic nerve distribution and arrhythmia☆

    PubMed Central

    Liu, Quan; Chen, Dongmei; Wang, Yonggang; Zhao, Xin; Zheng, Yang

    2012-01-01

    OBJECTIVE: To analyze the distribution characteristics of cardiac autonomic nerves and to explore the correlation between cardiac autonomic nerve distribution and arrhythmia. DATA RETRIEVAL: A computer-based retrieval was performed for papers examining the distribution of cardiac autonomic nerves, using heart, autonomic nerve, sympathetic nerve, vagus nerve, nerve distribution, rhythm and atrial fibrillation as the key words. SELECTION CRITERIA: A total of 165 studies examining the distribution of cardiac autonomic nerve were screened, and 46 of them were eventually included. MAIN OUTCOME MEASURES: The distribution and characteristics of cardiac autonomic nerves were observed, and immunohistochemical staining was applied to determine the levels of tyrosine hydroxylase and acetylcholine transferase (main markers of cardiac autonomic nerve distribution). In addition, the correlation between cardiac autonomic nerve distribution and cardiac arrhythmia was investigated. RESULTS: Cardiac autonomic nerves were reported to exhibit a disordered distribution in different sites, mainly at the surface of the cardiac atrium and pulmonary vein, forming a ganglia plexus. The distribution of the pulmonary vein autonomic nerve was prominent at the proximal end rather than the distal end, at the upper left rather than the lower right, at the epicardial membrane rather than the endocardial membrane, at the left atrium rather than the right atrium, and at the posterior wall rather than the anterior wall. The main markers used for cardiac autonomic nerves were tyrosine hydroxylase and acetylcholine transferase. Protein gene product 9.5 was used to label the immunoreactive nerve distribution, and the distribution density of autonomic nerves was determined using a computer-aided morphometric analysis system. CONCLUSION: The uneven distribution of the cardiac autonomic nerves is the leading cause of the occurrence of arrhythmia, and the cardiac autonomic nerves play an important role in

  20. Cardiac arrest during dipyridamole imaging

    SciTech Connect

    Blumenthal, M.S.; McCauley, C.S.

    1988-05-01

    A case of cardiac arrest and subsequent acute myocardial infarction occurring during thallium-201 imaging with oral dipyridamole augmentation is presented. Previous reports emphasizing the safety of this procedure are briefly reviewed and a recommendation for close hemodynamic and arrhythmia monitoring during the study is made. Large doses of oral dipyridamole may be contraindicated in patients with unstable angina.

  1. Catheter Ablation for Ventricular Arrhythmias

    PubMed Central

    Nof, Eyal; Stevenson, William G; John, Roy M

    2013-01-01

    Catheter ablation has emerged as an important and effective treatment option for many recurrent ventricular arrhythmias. The approach to ablation and the risks and outcomes are largely determined by the nature of the severity and type of underlying heart disease. In patients with structural heart disease, catheter ablation can effectively reduce ventricular tachycardia (VT) episodes and implantable cardioverter defibrillator (ICD) shocks. For VT and symptomatic premature ventricular beats that occur in the absence of structural heart disease, catheter ablation is often effective as the sole therapy. Advances in catheter technology, imaging and mapping techniques have improved success rates for ablation. This review discusses current approaches to mapping and ablation for ventricular arrhythmias. PMID:26835040

  2. Cardiac catheterization

    MedlinePlus

    Catheterization - cardiac; Heart catheterization; Angina - cardiac catheterization; CAD - cardiac catheterization; Coronary artery disease - cardiac catheterization; Heart valve - cardiac catheterization; Heart failure - ...

  3. Cardiac Dysautonomia in Huntington's Disease.

    PubMed

    Abildtrup, Mads; Shattock, Michael

    2013-01-01

    Huntington's disease is a fatal, hereditary, neurodegenerative disorder best known for its clinical triad of progressive motor impairment, cognitive deficits and psychiatric disturbances. Although a disease of the central nervous system, mortality surveys indicate that heart disease is a leading cause of death. The nature of such cardiac abnormalities remains unknown. Clinical findings indicate a high prevalence of autonomic nervous system dysfunction - dysautonomia - which may be a result of pathology of the central autonomic network. Dysautonomia can have profound effects on cardiac health, and pronounced autonomic dysfunction can be associated with neurogenic arrhythmias and sudden cardiac death. Significant advances in the knowledge of neural mechanisms in cardiac disease have recently been made which further aid our understanding of cardiac mortality in Huntington's disease. Even so, despite the evidence of aberrant autonomic activity the potential cardiac consequences of autonomic dysfunction have been somewhat ignored. In fact, underlying cardiac abnormalities such as arrhythmias have been part of the exclusion criteria in clinical autonomic Huntington's disease research. A comprehensive analysis of cardiac function in Huntington's disease patients is warranted. Further experimental and clinical studies are needed to clarify how the autonomic nervous system is controlled and regulated in higher, central areas of the brain - and how these regions may be altered in neurological pathology, such as Huntington's disease. Ultimately, research will hopefully result in an improvement of management with the aim of preventing early death in Huntington's disease from cardiac causes.

  4. Arrhythmia Management in the Elderly-Implanted Cardioverter Defibrillators and Prevention of Sudden Death.

    PubMed

    Manian, Usha; Gula, Lorne J

    2016-09-01

    We present an overview of arrhythmia management in elderly patients as it pertains to implantable cardioverter defibrillator (ICD) therapy and prevention of sudden death. Treatment of arrhythmia in elderly patients is fraught with challenges pertaining to goals of care and patient frailty. With an ever increasing amount of technology available, realistic expectations of therapy need to balance quality and quantity of life. The ICD is an important treatment option for selected patients at risk of ventricular arrhythmia and sudden cardiac death. However, the incidence of sudden death as a percentage of all-cause mortality decreases with age. Studies have reported that 20% of elderly patients might die within 1 year of an episode of life-threatening ventricular arrhythmia, but most because of nonarrhythmic causes. This illustrates the 'sudden cardiac death paradox,' with a great proportion of death in elderly patients, even those at risk for ventricular arrhythmias, attributable to medical conditions that cannot be addressed by an ICD. We discuss current practices in ICD therapy in elderly patients, existing evidence from registries and clinical trials, approaches to risk stratification, and important ethical considerations. Although the decision on whether ICD insertion is appropriate in the elderly population remains an area of uncertainty from an evidence-based and ethical perspective, we offer insight on potential clinical and research strategies for this growing population.

  5. How Can Death Due to Sudden Cardiac Arrest Be Prevented?

    MedlinePlus

    ... Trials Links Related Topics Arrhythmia Automated External Defibrillator Coronary Heart Disease Heart Failure Long QT Syndrome Send a link ... First Sudden Cardiac Arrest If you have severe coronary heart disease (CHD), you're at increased risk for SCA. ...

  6. The Association between Arrhythmia and Helicobacter pylori Infection: A Meta-Analysis of Case-Control Studies

    PubMed Central

    Yan, Jin; She, Qiang; Zhang, Yifeng; Cui, Chang; Zhang, Guoxin

    2016-01-01

    Arrhythmia is a common disease around the world and Helicobacter pylori (H. pylori) is a bacterium infecting 28% to 84% of subjects, depending on the population tested. However, the implication of H. pylori in cardiac arrhythmia is poorly understood. We performed this meta-analysis with an aim to identify the association between arrhythmia and H. pylori. We searched PubMed, Embase, Web of Science, and the Cochrane library databases to select studies on the association between arrhythmia and H. pylori. In the arrhythmia group, 392 (58.1%) were H. pylori-positive and in the control group 640 (47.8%) were H. pylori-positive. Compared to the controls, the infection rate of H. pylori was higher in patients with arrhythmia than in controls (odds ratio (OR) = 1.797, 95% confidence interval (CI): 1.081–2.988, p < 0.05). Subgroup analysis indicated that H. pylori infection was a risk factor for atrial fibrillation in Asia and Africa. Therefore, a correlation between H. pylori infection and arrhythmia may exist and H. pylori eradication may decrease the occurrence of arrhythmia, especially in Asia and Africa. PMID:27854353

  7. The Association between Arrhythmia and Helicobacter pylori Infection: A Meta-Analysis of Case-Control Studies.

    PubMed

    Yan, Jin; She, Qiang; Zhang, Yifeng; Cui, Chang; Zhang, Guoxin

    2016-11-16

    Arrhythmia is a common disease around the world and Helicobacter pylori (H. pylori) is a bacterium infecting 28% to 84% of subjects, depending on the population tested. However, the implication of H. pylori in cardiac arrhythmia is poorly understood. We performed this meta-analysis with an aim to identify the association between arrhythmia and H. pylori. We searched PubMed, Embase, Web of Science, and the Cochrane library databases to select studies on the association between arrhythmia and H. pylori. In the arrhythmia group, 392 (58.1%) were H. pylori-positive and in the control group 640 (47.8%) were H. pylori-positive. Compared to the controls, the infection rate of H. pylori was higher in patients with arrhythmia than in controls (odds ratio (OR) = 1.797, 95% confidence interval (CI): 1.081-2.988, p < 0.05). Subgroup analysis indicated that H. pylori infection was a risk factor for atrial fibrillation in Asia and Africa. Therefore, a correlation between H. pylori infection and arrhythmia may exist and H. pylori eradication may decrease the occurrence of arrhythmia, especially in Asia and Africa.

  8. Emergency therapy of maternal and fetal arrhythmias during pregnancy

    PubMed Central

    Trappe, Hans-Joachim

    2010-01-01

    Atrial premature beats are frequently diagnosed during pregnancy (PR); supraventricular tachycardia (SVT) (atrial tachycardia, AV-nodal reentrant tachycardia, circus movement tachycardia) is less frequently diagnosed. For acute therapy, electrical cardioversion with 50–100 J is indicated in all unstable patients (pts). In stable SVT, the initial therapy includes vagal maneuvers to terminate tachycardias. For short-term management, when vagal maneuvers fail, intravenous adenosine is the first choice drug and may safely terminate the arrhythmia. Ventricular premature beats are also frequently present during PR and benign in most of the pts; however, malignant ventricular tachyarrhythmias (sustained ventricular tachycardia [VT], ventricular flutter [VFlut] or ventricular fibrillation [VF]) may occur. Electrical cardioversion is necessary in all pts who are in hemodynamically unstable situation with life-threatening ventricular tachyarrhythmias. In hemodynamically stable pts, initial therapy with ajmaline, procainamide or lidocaine is indicated. In pts with syncopal VT, VF, VFlut or aborted sudden death, an implantable cardioverter-defibrillator is indicated. In pts with symptomatic bradycardia, a pacemaker can be implanted using echocardiography at any stage of PR. The treatment of the pregnant patient with cardiac arrhythmias requires important modifications of the standard practice of arrhythmia management. The goal of therapy is to protect the patient and fetus through delivery, after which chronic or definitive therapy can be administered. PMID:20606792

  9. Intraoperative MRI electrical noise and monitor ECG filters affect arrhythmia detection and identification.

    PubMed

    Bailey, Melissa; Kirchen, Gwynne; Bonaventura, Bridget; Rosborough, Kelly; Abdel-Rasoul, Mahmoud; Dzwonczyk, Roger

    2012-06-01

    Most electrical equipment in the modern operating room (OR) radiates electrical noise (EN) that can interfere with patient monitors. We have described the EN that an intraoperative magnetic resonance imaging (iMRI) system emits and have shown that this high-energy EN diminishes the quality of the ECG waveform during iMRI scans in our neurosurgical OR. We have also shown that the ECG signal filters in our iMRI-compatible patient monitor reduce this interference but, in the process, disturb the true morphology of the displayed waveform. This simulation study evaluates how iMRI-generated EN affects the ability of the anesthetist to detect and identify ECG arrhythmias and whether the patient monitor's ECG signal filters can improve arrhythmia recognition. Using an ECG simulator, we generated Lead II and V5 ECG signal segments that contained either no arrhythmia or one of four common cardiac arrhythmias. We filtered the ECG segments with four filters available on our iMRI-compatible monitor (Veris MR, MEDRAD Inc., Indianola, PA USA). We then digitized the segments and mixed simulated iMRI EN into the resultant tracings. With institutional approval and written informed consent, board-certified anesthesiologists reviewed the tracings, determined if an arrhythmia was present and identified the arrhythmia. We conducted the study anonymously. We reported the data as percent correct arrhythmia detection and correct arrhythmia identification. Thirty-one anesthesiologists completed the study. Overall, the participants correctly detected 79.5% (95% CI: 77.2, 81.7%) of the arrhythmias and correctly identified 62.5% (95% CI: 59.8, 65.3%) of the arrhythmias, regardless of EN presence. Although the proportions among monitor noise filters studied were not significant, the manufacturer-designated MR5 Veris MR filter optimized arrhythmia detection and arrhythmia identification for our participants, regardless if EN was present in the ECG tracings. In the neurosurgical OR, the

  10. Cardiorenal axis and arrhythmias: Will renal sympathetic denervation provide additive value to the therapeutic arsenal?

    PubMed

    van Brussel, Peter M; Lieve, Krystien V V; de Winter, Robbert J; Wilde, Arthur A M

    2015-05-01

    Disruption of sympathetic tone may result in the occurrence or maintenance of cardiac arrhythmias. Multiple arrhythmic therapies that intervene by influencing cardiac sympathetic tone are common in clinical practice. These vary from pharmaceutical (β-blockers, angiotensin-converting enzyme inhibitors, and calcium antagonists) to percutaneous/surgical (cardiac sympathetic denervation) interventions. In some patients, however, these therapies have insufficient prophylactic and therapeutic capabilities. A safe and effective additional therapy wherein sympathetic drive is further attenuated would be expedient. Recently, renal sympathetic denervation (RSD) has been subject of research for various sympathetic nervous system-related diseases. By its presumed afferent and efferent sympatholytic effects, RSD might indirectly attenuate sympathetic outflow via the brain to the heart but might also reduce systemic catecholamine excretion and might therefore reduce catecholamine-sensitive arrhythmias. RSD is subject of research for various sympathetically driven arrhythmias, both supraventricular and ventricular. In this review, we give an overview of the rationale behind RSD as potential therapy in mediating arrhythmias that are triggered by a disrupted sympathetic nervous system and discuss the presently available results from animal and human studies.

  11. Redox Control of Cardiac Excitability

    PubMed Central

    Aggarwal, Nitin T.

    2013-01-01

    Abstract Reactive oxygen species (ROS) have been associated with various human diseases, and considerable attention has been paid to investigate their physiological effects. Various ROS are synthesized in the mitochondria and accumulate in the cytoplasm if the cellular antioxidant defense mechanism fails. The critical balance of this ROS synthesis and antioxidant defense systems is termed the redox system of the cell. Various cardiovascular diseases have also been affected by redox to different degrees. ROS have been indicated as both detrimental and protective, via different cellular pathways, for cardiac myocyte functions, electrophysiology, and pharmacology. Mostly, the ROS functions depend on the type and amount of ROS synthesized. While the literature clearly indicates ROS effects on cardiac contractility, their effects on cardiac excitability are relatively under appreciated. Cardiac excitability depends on the functions of various cardiac sarcolemal or mitochondrial ion channels carrying various depolarizing or repolarizing currents that also maintain cellular ionic homeostasis. ROS alter the functions of these ion channels to various degrees to determine excitability by affecting the cellular resting potential and the morphology of the cardiac action potential. Thus, redox balance regulates cardiac excitability, and under pathological regulation, may alter action potential propagation to cause arrhythmia. Understanding how redox affects cellular excitability may lead to potential prophylaxis or treatment for various arrhythmias. This review will focus on the studies of redox and cardiac excitation. Antioxid. Redox Signal. 18, 432–468. PMID:22897788

  12. Terlipressin-induced ventricular arrhythmia.

    PubMed

    Urge, Ján; Sincl, Frantisek; Procházka, Vlastimil; Urbánek, Karel

    2008-01-01

    During intravenous treatment with terlipressin for recurrent gastrointestinal (GI) bleeding, a 50-year-old male with no history of heart disease developed a newly prolonged QT interval and torsade de pointes. Risk factors present for acquired long QT syndrome were mineral dysbalance and a history of alcohol abuse with hepatic impairment. The patient was brought back to a normal sinus rhythm after a single 300-J counter-shock. Terlipressin was discontinued, and the patient's QTc interval subsequently returned to baseline. During 6 weeks of monitoring, arrhythmia did not recur.

  13. Arrhythmias

    MedlinePlus

    ... the doctor. Pacemakers. A pacemaker is a small battery-operated device implanted into the body (near the ... to speed up the heartbeat. Defibrillators. A small battery-operated implantable cardioverter defibrillator (ICD) is surgically placed ...

  14. Arrhythmias

    MedlinePlus

    Abnormal heart rhythms; Bradycardia; Tachycardia; Fibrillation ... the more common abnormal heart rhythms are: Atrial fibrillation or flutter Atrioventricular nodal reentry tachycardia (AVNRT) Heart ...

  15. The use of external event monitoring (web-loop) in the elucidation of symptoms associated with arrhythmias in a general population

    PubMed Central

    Epifanio, Hindalis Ballesteros; Katz, Marcelo; Borges, Melania Aparecida; Corrêa, Alessandra da Graça; Cintra, Fátima Dumas; Grinberg, Rodrigo Leandro; Ludovice, Ana Cristina Pinotti Pedro; Valdigem, Bruno Pereira; da Silva, Nilton José Carneiro; Fenelon, Guilherme

    2014-01-01

    Objective To correlate arrhythmic symptoms with the presence of significant arrhythmias through the external event monitoring (web-loop). Methods Between January and December 2011, the web-loop was connected to 112 patients (46% of them were women, mean age 52±21 years old). Specific arrhythmic symptoms were defined as palpitations, pre-syncope and syncope observed during the monitoring. Supraventricular tachycardia, atrial flutter or fibrillation, ventricular tachycardia, pauses greater than 2 seconds or advanced atrioventricular block were classified as significant arrhythmia. The association between symptoms and significant arrhythmias were analyzed. Results The web-loop recorded arrhythmic symptoms in 74 (66%) patients. Of these, in only 14 (19%) patients the association between symptoms and significant cardiac arrhythmia was detected. Moreover, significant arrhythmia was found in 11 (9.8%) asymptomatic patients. There was no association between presence of major symptoms and significant cardiac arrhythmia (OR=0.57, CI95%: 0.21-1.57; p=0.23). Conclusion We found no association between major symptoms and significant cardiac arrhythmia in patients submitted to event recorder monitoring. Event loop recorder was useful to elucidate cases of palpitations and syncope in symptomatic patients. PMID:25295448

  16. Cardiac advanced life support-surgical guideline: overview and implementation.

    PubMed

    Herrmann, Cheryl

    2014-01-01

    Cardiac arrest in the immediate postoperative recovery period in a patient who underwent cardiac surgery is typically related to reversible causes-tamponade, bleeding, ventricular arrhythmias, or heart blocks associated with conduction problems. When treated promptly, 17% to 79% of patients who experience cardiac arrest after cardiac surgery survive to discharge. The Cardiac Advanced Life Support-Surgical (CALS-S) guideline provides a standardized algorithm approach to resuscitation of patients who experience cardiac arrest after cardiac surgery. The purpose of this article is to discuss the CALS-S guideline and how to implement it.

  17. Molecular Aspects of Exercise-induced Cardiac Remodeling.

    PubMed

    Bernardo, Bianca C; McMullen, Julie R

    2016-11-01

    Exercise-induced cardiac remodeling is typically an adaptive response associated with cardiac myocyte hypertrophy and renewal, increased cardiac myocyte contractility, sarcomeric remodeling, cell survival, metabolic and mitochondrial adaptations, electrical remodeling, and angiogenesis. Initiating stimuli/triggers of cardiac remodeling include increased hemodynamic load, increased sympathetic activity, and the release of hormones and growth factors. Prolonged and strenuous exercise may lead to maladaptive exercise-induced cardiac remodeling including cardiac dysfunction and arrhythmia. In addition, this article describes novel therapeutic approaches for the treatment of heart failure that target mechanisms responsible for adaptive exercise-induced cardiac remodeling, which are being developed and tested in preclinical models.

  18. Alterations in cardiac autonomic control in spinal cord injury.

    PubMed

    Biering-Sørensen, Fin; Biering-Sørensen, Tor; Liu, Nan; Malmqvist, Lasse; Wecht, Jill Maria; Krassioukov, Andrei

    2017-02-15

    A spinal cord injury (SCI) interferes with the autonomic nervous system (ANS). The effect on the cardiovascular system will depend on the extent of damage to the spinal/central component of ANS. The cardiac changes are caused by loss of supraspinal sympathetic control and relatively increased parasympathetic cardiac control. Decreases in sympathetic activity result in heart rate and the arterial blood pressure changes, and may cause arrhythmias, in particular bradycardia, with the risk of cardiac arrest in those with cervical or high thoracic injuries. The objective of this review is to give an update of the current knowledge related to the alterations in cardiac autonomic control following SCI. With this purpose the review includes the following subheadings: 2. Neuro-anatomical plasticity and cardiac control 2.1 Autonomic nervous system and the heart 2.2 Alteration in autonomic control of the heart following spinal cord injury 3. Spinal shock and neurogenic shock 3.1 Pathophysiology of spinal shock 3.2 Pathophysiology of neurogenic shock 4. Autonomic dysreflexia 4.1 Pathophysiology of autonomic dysreflexia 4.2 Diagnosis of autonomic dysreflexia 5. Heart rate/electrocardiography following spinal cord injury 5.1 Acute phase 5.2 Chronic phase 6. Heart rate variability 6.1 Time domain analysis 6.2 Frequency domain analysis 6.3 QT-variability index 6.4 Nonlinear (fractal) indexes 7. Echocardiography 7.1 Changes in cardiac structure following spinal cord injury 7.2 Changes in cardiac function following spinal cord injury 8. International spinal cord injury cardiovascular basic data set and international standards to document the remaining autonomic function in spinal cord injury.

  19. Arrhythmia Associated with Buprenorphine and Methadone Reported to the Food and Drug Administration

    PubMed Central

    Kao, David P; Haigney, Mark CP; Mehler, Philip S; Krantz, Mori J

    2015-01-01

    Aim To assess the relative frequency of reporting of adverse events involving ventricular arrhythmia, cardiac arrest, QTc prolongation, or torsade de pointes to the US Food and Drug Administration (FDA) between buprenorphine and methadone. Design Retrospective pharmacoepidemiologic study Setting Adverse drug events spontaneously reported to the FDA between 1969-June 2011 originating in 196 countries (71% events from the US). Cases Adverse event cases mentioning methadone (n=14,915) or buprenorphine (n=7,283) were evaluated against all other adverse event cases (n= 4,796,141). Measurements The primary outcome was the composite of ventricular arrhythmia or cardiac arrest. The secondary outcome was the composite of QTc prolongation or torsade de pointes. The proportional reporting ratio (PRR) was used to identify disproportionate reporting defined as a PRR>2, χ2 error>4, with ≥3 cases. Findings There were 132 (1.8%) ventricular arrhythmia/cardiac arrest and 19 (0.3%) QTc prolongation/torsade de pointes cases associated with buprenorphine compared with 1729 (11.6%) ventricular arrhythmia/cardiac arrest and 390 (2.6%) QTc prolongation/torsade de pointes cases involving methadone. PRRs associated with buprenorphine were not significant for ventricular arrhythmia/cardiac arrest (1.1 95% confidence interval (CI) 0.9–1.3, χ2=1.2) or QTc prolongation/torsade de pointes (1.0 95% CI 0.7–1.9, χ2=0.0006), but were for methadone (7.2 95% CI 6.9–7.5, χ2=9160; 10.6 95% CI 9.7–11.8, χ2=3305, respectively). Conclusion In spontaneously reported adverse events, methadone is associated with disproportionate reporting of cardiac arrhythmias, whereas buprenorphine is not. Although these findings probably reflect clinically relevant differences, a causal connection cannot be presumed and disproportionality analysis cannot quantify absolute risk per treatment episode. Population-based studies to definitively quantify differential incidence rates are warranted. PMID:26075588

  20. Effect of Global Cardiac Ischemia on Human Ventricular Fibrillation: Insights from a Multi-scale Mechanistic Model of the Human Heart

    PubMed Central

    Kazbanov, Ivan V.; Clayton, Richard H.; Nash, Martyn P.; Bradley, Chris P.; Paterson, David J.; Hayward, Martin P.; Taggart, Peter; Panfilov, Alexander V.

    2014-01-01

    Acute regional ischemia in the heart can lead to cardiac arrhythmias such as ventricular fibrillation (VF), which in turn compromise cardiac output and result in secondary global cardiac ischemia. The secondary ischemia may influence the underlying arrhythmia mechanism. A recent clinical study documents the effect of global cardiac ischaemia on the mechanisms of VF. During 150 seconds of global ischemia the dominant frequency of activation decreased, while after reperfusion it increased rapidly. At the same time the complexity of epicardial excitation, measured as the number of epicardical phase singularity points, remained approximately constant during ischemia. Here we perform numerical studies based on these clinical data and propose explanations for the observed dynamics of the period and complexity of activation patterns. In particular, we study the effects on ischemia in pseudo-1D and 2D cardiac tissue models as well as in an anatomically accurate model of human heart ventricles. We demonstrate that the fall of dominant frequency in VF during secondary ischemia can be explained by an increase in extracellular potassium, while the increase during reperfusion is consistent with washout of potassium and continued activation of the ATP-dependent potassium channels. We also suggest that memory effects are responsible for the observed complexity dynamics. In addition, we present unpublished clinical results of individual patient recordings and propose a way of estimating extracellular potassium and activation of ATP-dependent potassium channels from these measurements. PMID:25375999

  1. Right Ventricular Outflow Tract Arrhythmias: Benign Or Early Stage Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia?

    PubMed

    Lin Md, Tina; Conti Md, Sergio; Cipolletta Md, Laura; Marino Md, Vittoria; Zucchetti Md, Martina; Russo Md, Eleonora; Pizzamiglio Md, Francesca; Al-Mohani Md, Ghaliah; Pala Be, Salvatore; Catto Be PhD, Valentina; Di Biase Md PhD, Luigi; Natale Md, Andrea; Tondo Md PhD Fesc, Claudio; Carbucicchio Md, Corrado

    2014-12-01

    Ventricular arrhythmias (VAs) arising from the right ventricular outflow tract (RVOT) are a common and heterogeneous entity. Idiopathic right ventricular arrhythmias (IdioVAs) are generally benign, with excellent ablation outcomes and long-term arrhythmia-free survival, and must be distinguished from other conditions associated with VAs arising from the right ventricle: the differential diagnosis with arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is therefore crucial because VAs are one of the most important causes of sudden cardiac death (SCD) in young individuals even with early stage of the disease. Radiofrequency catheter ablation (RFCA) is a current option for the treatment of VAs but important differences must be considered in terms of indication, purposes and procedural strategies in the treatment of the two conditions. In this review, we comprehensively discuss clinical and electrophysiological features, diagnostic and therapeutic techniques in a compared analysis of these two entities.

  2. The developmental basis of adult arrhythmia: atrial fibrillation as a paradigm

    PubMed Central

    Kapur, Sunil; MacRae, Calum A.

    2013-01-01

    Normal cardiac rhythm is one of the most fundamental physiologic phenomena, emerging early in the establishment of the vertebrate body plan. The developmental pathways underlying the patterning and maintenance of stable cardiac electrophysiology must be extremely robust, but are only now beginning to be unraveled. The step-wise emergence of automaticity, AV delay and sequential conduction are each tightly regulated and perturbations of these patterning events is now known to play an integral role in pediatric and adult cardiac arrhythmias. Electrophysiologic patterning within individual cardiac chambers is subject to exquisite control and is influenced by early physiology superimposed on the underlying gene networks that regulate cardiogenesis. As additional cell populations migrate to the developing heart these too bring further complexity to the organ, as it adapts to the dynamic requirements of a growing organism. A comprehensive understanding of the developmental basis of normal rhythm will inform not only the mechanisms of inherited arrhythmias, but also the differential regional propensities of the adult heart to acquired arrhythmias. In this review we use atrial fibrillation as a generalizable example where the various factors are perhaps best understood. PMID:24062689

  3. Atrial Fibrillation and Ventricular Arrhythmias: Sex Differences in Electrophysiology, Epidemiology, Clinical Presentation, and Clinical Outcomes.

    PubMed

    Gillis, Anne M

    2017-02-07

    Sex-specific differences in the epidemiology, pathophysiology, clinical presentation, clinical treatment, and clinical outcomes of atrial fibrillation (AF), sustained ventricular arrhythmias, and sudden cardiac death are recognized. Sex hormones cause differences in cardiac electrophysiological parameters between men and women that may affect the risk for arrhythmias. The incidence and prevalence of AF is lower in women than in men. However, because women live longer and AF prevalence increases with age, the absolute number of women with AF exceeds that of men. Women with AF are more symptomatic, present with more atypical symptoms, and report worse quality of life in comparison with men. Female sex is an independent risk factor for death or stroke attributable to AF. Oral anticoagulation therapy for stroke prevention has similar efficacy for men and women, but older women treated with warfarin have a higher residual risk of stroke in comparison with men. Women with AF are less likely to receive rhythm control antiarrhythmic drug therapy, electric cardioversion, or catheter ablation in comparison with men. The incidence and prevalence of sustained ventricular arrhythmias and sudden cardiac death are lower in women than in men. Women receiving implantable cardioverter defibrillators for primary prevention of sudden cardiac death are less likely to experience sustained ventricular arrhythmias in comparison with men. In contrast, women receiving a cardiac resynchronization therapy implantable cardioverter defibrillator for the treatment of heart failure are more likely to benefit than men. Women are less likely to be referred for implantable cardioverter defibrillator therapy despite current guideline recommendations. Women are more likely to experience a significant complication related to implantable cardioverter defibrillator implantation in comparison with men. Whether sex differences in treatment decisions reflect patient preferences or treatment biases requires

  4. Atrial Arrhythmia Summit: Post Summit Report

    NASA Technical Reports Server (NTRS)

    Barr, Yael

    2010-01-01

    The Atrial Arrhythmia Summit brought together nationally and internationally recognized experts in cardiology, electrophysiology, exercise physiology, and space medicine in an effort to elucidate the mechanisms, risk factors, and management of atrial arrhythmias in the unique occupational cohort of the U.S. astronaut corps.

  5. Evaluation of cardiac emboli source

    PubMed Central

    Michels, M.; Meijboom, F.J.; ten Cate, F.J.

    2005-01-01

    Background Evaluating the source of cardiac embolism is one of the most frequent reasons for cardiac consultation. Methods In 2003, 99 patients were referred for the evaluation of the source of cardiac emboli. Evaluation included history, physical examination, ECG, transoesophageal echocardiography (TOE) with contrast and 24-hour Holter electrocardiography. Results Altogether, 58 men and 41 women were studied. In 32 patients a possible source of the cardiac emboli was found. Two patients were in atrial fibrillation. Of the patients, 16 had a patent foramen ovale (PFO) and six patients a PFO and atrial septum aneurysm (ASA). Two patients had a thrombus in the left atrial appendage and 14 had severe atherosclerosis in the aortic arch. In eight patients we found two possible cardiac sources of embolism. 24-hour Holter recording did not detect any emboligenic arrhythmias. Conclusion A possible cardiac source of embolism was found in 32% of the patients referred. TOE is the ideal tool to visualise the interatrial septum, left atrial appendage and aortic arch. We advise performing a TOE with contrast in young stroke patients and in older patients with a stroke likely to be caused by an embolism of cardiac origin. 24-hour Holter recording did not detect any emboligenic arrhythmias and should only be done in selected cases. ImagesFigure 1Figure 2 PMID:25696441

  6. Resolution of abnormal cardiac MRI T2 signal following immune suppression for cardiac sarcoidosis.

    PubMed

    Crouser, Elliott D; Ruden, Emily; Julian, Mark W; Raman, Subha V

    2016-08-01

    Cardiac MR (CMR) with late gadolinium enhancement is commonly used to detect cardiac damage in the setting of cardiac sarcoidosis. The addition of T2 mapping to CMR was recently shown to enhance cardiac sarcoidosis detection and correlates with increased cardiac arrhythmia risk. This study was conducted to determine if CMR T2 abnormalities and related arrhythmias are reversible following immune suppression therapy. A retrospective study of subjects with cardiac sarcoidosis with abnormal T2 signal on baseline CMR and a follow-up CMR study at least 4 months later was conducted at The Ohio State University from 2011 to 2015. Immune suppression treated participants had a significant reduction in peak myocardial T2 value (70.0±5.5 vs 59.2±6.1 ms, pretreatment vs post-treatment; p=0.017), and 83% of immune suppression treated subjects had objective improvement in cardiac arrhythmias. Two subjects who had received inadequate immune suppression treatment experienced progression of cardiac sarcoidosis. This report indicates that abnormal CMR T2 signal represents an acute inflammatory manifestation of cardiac sarcoidosis that is potentially reversible with adequate immune suppression therapy.

  7. Effect of prophylaxis of magnesium sulfate for reduction of postcardiac surgery arrhythmia: Randomized clinical trial

    PubMed Central

    Naghipour, Bahman; Faridaalaee, Gholamreza; Shadvar, Kamran; Bilehjani, Eissa; Khabaz, Ashkan Heyat; Fakhari, Solmaz

    2016-01-01

    Background: Arrhythmia is a common complication after heart surgery and is a major source of morbidity and mortality. Aims: This study aimed to study the effect of magnesium sulfate (MgSO4) for reduction of postcardiac surgery arrhythmia. Setting and Design: This study is performed in the cardiac operating room and Intensive Care Unit (ICU) of Shahid Madani Hospital of Tabriz (Iran) between January 1, 2014, and September 30, 2014. This study is a double-blind, randomized controlled trial. Materials and Methods: In Group 1 (group magnesium [Mg]), eighty patients received 30 mg/kg MgSO4 in 500 cc normal saline and in Group 2 (group control), eighty patients received 500 cc normal saline alone. Statistical Analysis: The occurrence of arrhythmia was compared between groups by Chi-square and Fisher's exact test. In addition, surgical time, length of ICU stay, and length of hospital stay were compared by independent t-test. P < 0.05 was considered as significant. Results: There was a significant difference in the incidence of arrhythmia between two groups (P = 0.037). The length of ICU stay was 3.4 ± 1.4 and 3.73 ± 1.77 days in group MgSO4 and control group, respectively, and there was no statistically significant difference between two groups (P = 0.2). Conclusion: Mg significantly decreases the incidence of all type of postcardiac surgery arrhythmia and hospital length of stay at patients undergo cardiac surgery. We offer prophylactic administration of Mg at patients undergo cardiac surgery. PMID:27716697

  8. Irreversible Electroporation Near the Heart: Ventricular Arrhythmias Can Be Prevented With ECG Synchronization

    PubMed Central

    Deodhar, Ajita; Dickfeld, Timm; Single, Gordon W.; Hamilton, William C.; Thornton, Raymond H.; Sofocleous, Constantinos T.; Maybody, Majid; Gónen, Mithat; Rubinsky, Boris; Solomon, Stephen B.

    2013-01-01

    OBJECTIVE Irreversible electroporation is a nonthermal ablative tool that uses direct electrical pulses to create irreversible membrane pores and cell death. The ablation zone is surrounded by a zone of reversibly increased permeability; either zone can cause cardiac arrhythmias. Our purpose was to establish a safety profile for the use of irreversible electroporation close to the heart. MATERIALS and METHODS The effect of unsynchronized and synchronized (with the R wave on ECG) irreversible electroporation in swine lung and myocardium was studied in 11 pigs. Twelve lead ECG recordings were analyzed by an electrophysiologist for the presence of arrhythmia. Ventricular arrhythmias were categorized as major events. Minor events included all other dysrhythmias or ECG changes. Cardiac and lung tissue was submitted for histopathologic analysis. Electrical field modeling was performed to predict the distance from the applicators over which cells show electroporation-induced increased permeability. RESULTS At less than or equal to 1.7 cm from the heart, fatal (major) events occurred with all unsynchronized irreversible electroporation. No major and three minor events were seen with synchronized irreversible electroporation. At more than 1.7 cm from the heart, two minor events occurred with only unsynchronized irreversible electroporation. Electrical field modeling correlates well with the clinical results, revealing increased cell membrane permeability up to 1.7 cm away from the applicators. Complete lung ablation without intervening live cells was seen. No myocardial injury was seen. CONCLUSION Unsynchronized irreversible electroporation close to the heart can cause fatal ventricular arrhythmias. Synchronizing irreversible electroporation pulse delivery with absolute refractory period avoids significant cardiac arrhythmias. PMID:21343484

  9. Optogenetic defibrillation terminates ventricular arrhythmia in mouse hearts and human simulations

    PubMed Central

    Boyle, Patrick M.; Vogt, Christoph C.; Karathanos, Thomas V.; Arevalo, Hermenegild J.; Fleischmann, Bernd K.; Trayanova, Natalia A.

    2016-01-01

    Ventricular arrhythmias are among the most severe complications of heart disease and can result in sudden cardiac death. Patients at risk currently receive implantable defibrillators that deliver electrical shocks to terminate arrhythmias on demand. However, strong electrical shocks can damage the heart and cause severe pain. Therefore, we have tested optogenetic defibrillation using expression of the light-sensitive channel channelrhodopsin-2 (ChR2) in cardiac tissue. Epicardial illumination effectively terminated ventricular arrhythmias in hearts from transgenic mice and from WT mice after adeno-associated virus–based gene transfer of ChR2. We also explored optogenetic defibrillation for human hearts, taking advantage of a recently developed, clinically validated in silico approach for simulating infarct-related ventricular tachycardia (VT). Our analysis revealed that illumination with red light effectively terminates VT in diseased, ChR2-expressing human hearts. Mechanistically, we determined that the observed VT termination is due to ChR2-mediated transmural depolarization of the myocardium, which causes a block of voltage-dependent Na+ channels throughout the myocardial wall and interrupts wavefront propagation into illuminated tissue. Thus, our results demonstrate that optogenetic defibrillation is highly effective in the mouse heart and could potentially be translated into humans to achieve nondamaging and pain-free termination of ventricular arrhythmia. PMID:27617859

  10. Characterization of fetal arrhythmias by means of fetal magnetocardiography in three cases of difficult ultrasonographic imaging.

    PubMed

    Comani, Silvia; Liberati, Marco; Mantini, Dante; Gabriele, Elisabetta; Brisinda, Donatella; Di Luzio, Silvano; Fenici, Riccardo; Romani, Gian Luca

    2004-12-01

    Characterization of ultrasound detected fetal arrhythmias is generally performed by means of M-mode and pulsed Doppler echocardiography (fECHO), sonographic techniques that allow only indirect and approximate reconstruction of the true electrophysiological events that occur in the fetal heart. Several studies demonstrated the ability of fetal magnetocardiography (fMCG) to identify fetal arrhythmias. We report on three women, studied after the 32nd gestational week, who were referred for fMCG because of unsatisfying fetal cardiac visualization with fECHO due to maternal obesity, fetus in constant dorsal position hiding the fetal heart, intrauterine growth retardation, and oligohydramnios. Minor pericardial effusion was present in the third patient and digoxin therapy was given. FMCG were recorded with a 77-channel MCG system working in a shielded room. Independent Component Analysis (FastICA algorithm) was used to reconstruct fetal signals. The good quality of the retrieved fetal signals allowed real-time detection of arrhythmias and their classification as supraventricular extrasystoles (SVE), with/without aberrant ventricular conduction and/or atrioventricular block. The time course of the fetal cardiac rhythm was reconstructed for the entire recording duration; hence, fetal heart rate variability could be studied in time and frequency. Since isolated extrasystoles may progress to more hazardous supraventricular tachycardias, the noninvasive antenatal characterization of, even transient, fetal arrhythmias and their monitoring during pregnancy can be of great clinical impact.

  11. Prolonged Oral Administration of Oleuropein Might Protect Heart against Aconitine-induced Arrhythmia

    PubMed Central

    Esmailidehaj, Mansour; Mirhosseini, Seyed-Jalil; Rezvani, Mohammad Ebrahim; Rasoulian, Bahram; Mosaddeghmehrjardi, Mohammad Hossein; Haghshenas, Damoon

    2012-01-01

    In this study, it was surveyed to know whether an oral single dose of oleuropein could mimic the cardiac preconditioning in rats’ hearts or whether its prolonged oral administration could protect the heart against the aconitine-induced arrhythmia in rats. Eighty male Wistar rats were divided into two series (n = 8 in each group). In the first series, all groups (except the control (Con) group) were given a single oral dose of oleuropein (20 mg/Kg) 1, 3, 24 and 48 h before the infusion of aconitine. In the second series, except the Con group, the other four groups were given oral oleuropein (20 mg/Kg/day) for 3, 7, 14 and 28 days, before the infusion of aconitine. Electrocardiogram was recorded to monitor arrhythmia. Data of the first series showed that the initiation time of arrhythmia, the initiation of ventricular tachycardia (VT), the numbers of reversible ventricular fibrillation (VF) and the death time had no significant difference compared with Con group. In the second series, a significant protection was occurred only in the 28 days group that was evident with increased initiation time of arrhythmia, increased initiation time of VT, and increased the number of reversible VF and death time in compared to the Con group. The findings of this study show that the oral administration of a single dose of oleuropein could not mimic the preconditioning effects in rat hearts, but the prolonged administration of oleuropein for about four weeks could protect the heart against aconitine-induced arrhythmia. PMID:24250560

  12. Postoperative atrial fibrillation in non-cardiac and cardiac surgery: an overview.

    PubMed

    Bessissow, A; Khan, J; Devereaux, P J; Alvarez-Garcia, J; Alonso-Coello, P

    2015-06-01

    Postoperative atrial fibrillation (POAF) is the most common perioperative cardiac arrhythmia. A major risk factor for POAF is advanced age, both in non-cardiac and cardiac surgery. Following non-cardiac surgery, it is important to correct reversible conditions such as electrolytes imbalances to prevent the occurrence of POAF. Management of POAF consists of rate control and therapeutic anticoagulation if POAF persists for > 48 h and CHADS2 score > 2. After cardiac surgery, POAF affects a larger amount of patients. In addition to age, valve surgery carries the greatest risk for new AF. Rate control is the mainstay therapy in these patients. Prediction, prevention, and management of POAF should be further studied.

  13. Selective Kv1.5 blockers: development of (R)-1-(methylsulfonylamino)-3-[2-(4-methoxyphenyl)ethyl]-4-(4-methoxyphenyl)-2-imidazolidinone (KVI-020/WYE-160020) as a potential treatment for atrial arrhythmia.

    PubMed

    Blass, Benjamin E; Fensome, Andrew; Trybulski, Eugene; Magolda, Ronald; Gardell, Stephen J; Liu, Kun; Samuel, Manoj; Feingold, Irene; Huselton, Christine; Jackson, Chris M; Djandjighian, Laurent; Ho, Douglas; Hennan, James; Janusz, John M

    2009-11-12

    Atrial fibrillation is the most prevalent form of cardiac arrhythmia. Current treatments extend the atrial effective refractory period by nonselective blockade of cardiac ion channels. An alternative approach selectively targeting the Kv1.5 ion channel offers the opportunity for therapeutic benefit with decreased risk of adverse cardiovascular events. KVI-020 (4g) successfully demonstrated antiarrhythmic efficacy in a canine arrhythmia model, and these findings support its utility as an antiarrhythmic agent.

  14. Computer simulation of the reentrant cardiac arrhythmias in ischemic myocardium.

    PubMed

    Zhang, Hong; Yang, Lin; Jin, Yin-bin; Zhang, Zhen-xi; Huang, Yi-zhuo

    2005-09-30

    Computer simulation was performed to determine how reentrant activity could occur due to the spatial heterogeneity in refractoriness induced by the regional ischemia. Two regional ischemic models were developed by decreasing the intracellular ATP concentration, reducing conductance of the inward Na+ current and increasing the extracellular K+ concentration on the two-dimensional sheet. Operator splitting method was used to integrate the models. The vulnerability to reentry was estimated from the timings of premature stimuli on the constructed models, which could result in unidirectionally propagating action potentials. Two kinds of sustained spiral waves and their Pseudo-Electroscardiograms were observed in numerical simulation. The results showed that the dispersion of refractory period increased with ischemic aggravation, and led to augment of the vulnerable window. A permature stimulation within the vulnerable window could easily induce spiral reentry. The Pseudo-Electrocardiograms of the spiral waves exhibited monomorphic tachycardiac waveforms. Thus, the spatial heterogeneity in refractoriness could be a substrate for reentrant ventricular tachyarrhythmias on the regional ischemic tissue.

  15. [Intrinsic cardiac ganglia].

    PubMed

    Birand, Ahmet

    2008-12-01

    Heart has been considered as the source and the seat of emotions, passion and love. But from the dawn of XIXth century, scientists have emphasized that the heart, though life depends on its ceaseless activity, is merely a electromechanical pump, pumping oxygenated blood. Nowadays, we all know that heart pumps blood commensurate with the needs of the body and this unending toil, and its regulation depends on the intrinsic properties of the myocardium, Frank-Starling Law and neurohumoral contribution. It has been understood, though not clearly enough, that these time-tensions may cause structural or functional cardiac impairments and arrhythmias are related to the autonomic nervous system. Less well known and less taken in account in daily cardiology practice is the fact that heart has an intrinsic cardiac nervous system, or "heart brain" consisting of complex ganglia, intrinsic cardiac ganglia containing afferent (receiving), local circuit (interneurons) and efferent (transmitting) sympathetic and parasympathetic neurons. This review enlightens structural and functional aspects of intrinsic cardiac ganglia as the very first step in the regulation of cardiac function. This issue is important for targets of pharmacological treatment and techniques of cardiac surgery interventions as repair of septal defects, valvular interventions and congenital corrections.

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

    SciTech Connect

    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{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

  17. Convulsive Syncope Induced by Ventricular Arrhythmia Masquerading as Epileptic Seizures: Case Report and Literature Review

    PubMed Central

    Sabu, John; Regeti, Kalyani; Mallappallil, Mary; Kassotis, John; Islam, Hamidul; Zafar, Shoaib; Khan, Rafay; Ibrahim, Hiyam; Kanta, Romana; Sen, Shuvendu; Yousif, Abdalla; Nai, Qiang

    2016-01-01

    It is important but difficult to distinguish convulsive syncope from epileptic seizure in many patients. We report a case of a man who presented to emergency department after several witnessed seizure-like episodes. He had a previous medical history of systolic heart failure and automated implantable converter defibrillator (AICD) in situ. The differential diagnoses raised were epileptic seizures and convulsive syncope secondary to cardiac arrhythmia. Subsequent AICD interrogation revealed ventricular tachycardia and fibrillation (v-tach/fib). Since convulsive syncope and epileptic seizure share many similar clinical features, early diagnosis is critical for choosing the appropriate management and preventing sudden cardiac death in patients with presumed epileptic seizure. PMID:27429683

  18. Flecainide: Current status and perspectives in arrhythmia management

    PubMed Central

    Andrikopoulos, George K; Pastromas, Sokratis; Tzeis, Stylianos

    2015-01-01

    Flecainide acetate is a class IC antiarrhythmic agent and its clinical efficacy has been confirmed by the results of several clinical trials. Nowadays, flecainide is recommended as one of the first line therapies for pharmacological conversion as well as maintenance of sinus rhythm in patients with atrial fibrillation and/or supraventricular tachycardias. Based on the Cardiac Arrhythmia Suppression Trial study results, flecainide is not recommended in patients with structural heart disease due to high proarrhythmic risk. Recent data support the role of flecainide in preventing ventricular tachyarrhythmias in patients with catecholaminergic polymorphic ventricular tachycardia associated both with ryanodine receptor and calsequestrin mutations. We herein review the current clinical data related to flecainide use in clinical practice and some concerns about its role in the management of patients with coronary artery disease. PMID:25717355

  19. The effects of dilazep on reperfusion arrhythmias.

    PubMed

    Sugiyama, S; Kondo, T; Ajioka, M; Hattori, M; Nagai, S; Ozawa, T

    1985-01-01

    The effects of 3,3'-(perhydro-1,4-diazepine-1,4-diyl) (propyl-3,4,5-trimethoxybenzoate (dilazep, Comelian) on reperfusion arrhythmias were investigated. 49 adult mongrel dogs were divided into 2 groups; the control group (n = 38) and the dilazep group (n = 11). 15 min after premedication with physiological saline or dilazep (2 mg/kg), the left anterior descending coronary artery was occluded for 15 min and then reperfused for 5 min. 12 dogs (32%) of the control developed "reperfusion arrhythmias" (arrhythmias cases) but 26 did not (non-arrhythmias cases). None of the 11 dogs pretreated with dilazep developed arrhythmias (dilazep group). Immediately after 5 min of reperfusion, plasma membrane and microsomes were prepared from the normal and reperfused myocardium. In the arrhythmias cases of the control group, an increase in free fatty acids and a decrease in phospholipids of plasma membrane obtained from the reperfused myocardium were observed. The endogenous phospholipase activity in the heart microsomes obtained from reperfused myocardium increased significantly compared with that from the normal myocardium. In the non-arrhythmias cases of the control group and in the dilazep group, there was no significant difference in the contents of free fatty acids and phospholipids in plasma membrane between normal and reperfused area. Phospholipase activity in the microsomes prepared from the reperfused myocardium did not change significantly compared with that in the microsomes from normal area in these groups. These results suggest that the activation of phospholipases associated with coronary reperfusion is closely related to the development of reperfusion arrhythmias.

  20. Pharmacological inhibition of FAAH activity in rodents: A promising pharmacological approach for psychological-cardiac comorbidity?

    PubMed

    Carnevali, Luca; Rivara, Silvia; Nalivaiko, Eugene; Thayer, Julian F; Vacondio, Federica; Mor, Marco; Sgoifo, Andrea

    2017-03-01

    Numerous studies have documented a link between psychological disorders and cardiac disease. Yet, no systematic attempts have been made to develop pharmacological approaches for mood and anxiety disorders that could also be beneficial for cardiac health. The endocannabinoid system has been implicated in the regulation of stress, emotional behavior and cardiovascular function. General preclinical findings indicate that the endocannabinoid anandamide modulates physiological and behavioral stress responses and may also protect the heart from arrhythmias. Moreover, recent experimental studies suggest that pharmacological enhancement of anandamide signaling via inhibition of its degrading enzyme fatty acid amide hydrolase (FAAH) exerts anxiolytic- and antidepressive-like effects and improves cardiac autonomic function and the electrical stability of the myocardium in rodent models that reproduce aspects of human psychological/cardiac comorbidity. Here we summarize and discuss such experimental findings, which might guide future preclinical studies towards a systematic evaluation of the therapeutic potential of pharmacological approaches that target FAAH activity for the treatment of the comorbidity between psychological disorders and cardiac disease.

  1. Prevalence of arrhythmias during exercise stress testing in patients with congenital heart disease and severe right ventricular conduit dysfunction.

    PubMed

    Priromprintr, Bryant; Rhodes, Jonathan; Silka, Michael J; Batra, Anjan S

    2014-08-01

    The utility of cardiopulmonary exercise testing (CPET) to define the risks of arrhythmia and sudden death in postoperative patients with congenital heart disease (CHD) remains uncertain. As part of the US Melody valve trial, prospective standardized CPET, along with echocardiography, cardiac magnetic resonance imaging, and cardiac catheterization, were performed in 170 CHD patients with right ventricular outflow tract conduit dysfunction before Melody valve implantation. Ventricular premature complexes (VPC) occurred in 75 patients (44%) and were common during all phases of CPET (13% baseline, 24% exercise, and 23% recovery). Although no subjects had sustained arrhythmias, 2 had nonsustained ventricular tachycardia and 3 had nonsustained supraventricular tachycardia during recovery. There were no statistically significant differences between patients with or without VPCs in echocardiographic, cardiac magnetic resonance imaging, or catheterization measures of cardiac function. However, clinical parameters of age, New York Heart Association functional class ≥II, and ≥3 cardiac surgical procedures were correlated with VPCs. Persistent ventricular ectopy during all exercise stages was present in 11 patients (6.5%), including 3 of the 4 patients who died during follow-up. In conclusion, VPCs were common during CPET, although they were not correlated with various measures of hemodynamic impairment; conversely, increased age, functional class, and number of surgeries were correlated with an increased prevalence of VPCs. CPET appears to be of minimal risk for sustained arrhythmia provocation in CHD patients with right ventricular outflow tract conduits and various degrees of advanced subpulmonary ventricular dysfunction.

  2. Testing the burden of rare variation in arrhythmia-susceptibility genes provides new insights into molecular diagnosis for Brugada syndrome.

    PubMed

    Le Scouarnec, Solena; Karakachoff, Matilde; Gourraud, Jean-Baptiste; Lindenbaum, Pierre; Bonnaud, Stéphanie; Portero, Vincent; Duboscq-Bidot, Laëtitia; Daumy, Xavier; Simonet, Floriane; Teusan, Raluca; Baron, Estelle; Violleau, Jade; Persyn, Elodie; Bellanger, Lise; Barc, Julien; Chatel, Stéphanie; Martins, Raphaël; Mabo, Philippe; Sacher, Frédéric; Haïssaguerre, Michel; Kyndt, Florence; Schmitt, Sébastien; Bézieau, Stéphane; Le Marec, Hervé; Dina, Christian; Schott, Jean-Jacques; Probst, Vincent; Redon, Richard

    2015-05-15

    The Brugada syndrome (BrS) is a rare heritable cardiac arrhythmia disorder associated with ventricular fibrillation and sudden cardiac death. Mutations in the SCN5A gene have been causally related to BrS in 20-30% of cases. Twenty other genes have been described as involved in BrS, but their overall contribution to disease prevalence is still unclear. This study aims to estimate the burden of rare coding variation in arrhythmia-susceptibility genes among a large group of patients with BrS. We have developed a custom kit to capture and sequence the coding regions of 45 previously reported arrhythmia-susceptibility genes and applied this kit to 167 index cases presenting with a Brugada pattern on the electrocardiogram as well as 167 individuals aged over 65-year old and showing no history of cardiac arrhythmia. By applying burden tests, a significant enrichment in rare coding variation (with a minor allele frequency below 0.1%) was observed only for SCN5A, with rare coding variants carried by 20.4% of cases with BrS versus 2.4% of control individuals (P = 1.4 × 10(-7)). No significant enrichment was observed for any other arrhythmia-susceptibility gene, including SCN10A and CACNA1C. These results indicate that, except for SCN5A, rare coding variation in previously reported arrhythmia-susceptibility genes do not contribute significantly to the occurrence of BrS in a population with European ancestry. Extreme caution should thus be taken when interpreting genetic variation in molecular diagnostic setting, since rare coding variants were observed in a similar extent among cases versus controls, for most previously reported BrS-susceptibility genes.

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

    PubMed

    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

  4. Cardiac Involvement in Peripheral Neuropathies.

    PubMed

    Burakgazi, Ahmet Z; AlMahameed, Soufian

    2016-03-01

    Cardiac autonomic neuropathy (CAN) is the least recognized and understood complication of peripheral neuropathy. However, because of its potential adverse effects including sudden death, CAN is one of the most important forms of autonomic neuropathies. CAN presents with different clinical manifestations including postural hypotension, exercise intolerance, fluctuation of blood pressure and heart rate, arrhythmia, and increased risk of myocardial infarction. In this article, the prevalence, clinical presentations, and management of cardiac involvement in certain peripheral neuropathies, including diabetic neuropathy, Guillain-Barré syndrome, chronic inflammatory polyneuropathy, human immunodeficiency virus-associated neuropathy, hereditary neuropathies, and amyloid neuropathy are examined in detail.

  5. VANADIUM EXPOSURE ALTERS SPONTANEOUS BEAT RATE AND GENE EXPRESSION OF CULTURED CARDIAC MYOCYTES

    EPA Science Inventory

    Ambient air pollution particulate matter (PM) exposure is associated with increased morbidity and mortality. Recent toxicological studies report PM-induced changes in a number of cardiac parameters, including heart rate variability, arrhythmias, repolarization, and internal defib...

  6. Noninvasive low-frequency electromagnetic stimulation of the left stellate ganglion reduces myocardial infarction-induced ventricular arrhythmia

    PubMed Central

    Wang, Songyun; Zhou, Xiaoya; Huang, Bing; Wang, Zhuo; Zhou, Liping; Wang, Menglong; Yu, Lilei; Jiang, Hong

    2016-01-01

    Noninvasive magnetic stimulation has been widely used in autonomic disorders in the past few decades, but few studies has been done in cardiac diseases. Recently, studies showed that low-frequency electromagnetic field (LF-EMF) might suppress atrial fibrillation by mediating the cardiac autonomic nervous system. In the present study, the effect of LF-EMF stimulation of left stellate ganglion (LSG) on LSG neural activity and ventricular arrhythmia has been studied in an acute myocardium infarction canine model. It is shown that LF-EMF stimulation leads to a reduction both in the neural activity of LSG and in the incidence of ventricular arrhythmia. The obtained results suggested that inhibition of the LSG neural activity might be the causal of the reduction of ventricular arrhythmia since previous studies have shown that LSG hyperactivity may facilitate the incidence of ventricular arrhythmia. LF-EMF stimulation might be a novel noninvasive substitute for the existing implant device-based electrical stimulation or sympathectomy in the treatment of cardiac disorders. PMID:27470078

  7. Localization of the site of origin of reentrant arrhythmia from body surface potential maps: a model study

    NASA Astrophysics Data System (ADS)

    Liu, Chenguang; Li, Guanglin; He, Bin

    2005-04-01

    We have developed a model-based imaging approach to estimate the site of origin of reentrant arrhythmia from body surface potential maps (BSPMs), with the aid of a cardiac arrhythmia model. The reentry was successfully simulated and maintained in the cardiac model, and the simulated ECG waveforms over the body surface corresponding to a maintained reentry have evident characteristics of ventricular tachycardia. The performance of the inverse imaging approach was evaluated by computer simulations. The present simulation results show that an averaged localization error of about 1.5 mm, when 5% Gaussian white noise was added to the BSPMs, was detected. The effects of the heart-torso geometry uncertainty on the localization were also initially assessed and the simulation results suggest that no significant influence was observed when 10% torso geometry uncertainty or 10 mm heart position shifting was considered. The present simulation study suggests the feasibility of localizing the site of origin of reentrant arrhythmia from non-invasive BSPMs, with the aid of a cardiac arrhythmia model.

  8. Canadian Cardiovascular Society 2009 Consensus Conference on the management of adults with congenital heart disease: complex congenital cardiac lesions.

    PubMed

    Silversides, Candice K; Salehian, Omid; Oechslin, Erwin; Schwerzmann, Markus; Vonder Muhll, Isabelle; Khairy, Paul; Horlick, Eric; Landzberg, Mike; Meijboom, Folkert; Warnes, Carole; Therrien, Judith

    2010-03-01

    With advances in pediatric cardiology and cardiac surgery, the population of adults with congenital heart disease (CHD) has increased. In the current era, there are more adults with CHD than children. This population has many unique issues and needs. They have distinctive forms of heart failure and their cardiac disease can be associated with pulmonary hypertension, thromboemboli, complex arrhythmias and sudden death. Medical aspects that need to be considered relate to the long-term and multisystemic effects of single ventricle physiology, cyanosis, systemic right ventricles, complex intracardiac baffles and failing subpulmonary right ventricles. Since the 2001 Canadian Cardiovascular Society Consensus Conference report on the management of adults with CHD, there have been significant advances in the field of adult CHD. Therefore, new clinical guidelines have been written by Canadian adult CHD physicians in collaboration with an international panel of experts in the field. Part III of the guidelines includes recommendations for the care of patients with complete transposition of the great arteries, congenitally corrected transposition of the great arteries, Fontan operations and single ventricles, Eisenmenger's syndrome, and cyanotic heart disease. Topics addressed include genetics, clinical outcomes, recommended diagnostic workup, surgical and interventional options, treatment of arrhythmias, assessment of pregnancy risk and follow-up requirements. The complete document consists of four manuscripts, which are published online in the present issue of The Canadian Journal of Cardiology. The complete document and references can also be found at www.ccs.ca or www.cachnet.org.

  9. Cardiac surgery for a patient with Andersen-Tawil syndrome.

    PubMed

    Nagashima, Mitsugi; Higaki, Takashi; Seike, Yoshimasa; Yokoyama, Yuichiro

    2010-07-01

    Andersen-Tawil syndrome is an uncommon inherited autosomal disorder characterized by a prolonged QT interval, periodic paralysis, and dysmorphic features. The deleterious effects of cardioplegia on periodic paralysis and cardiac arrhythmia are unknown, and no studies have reported the performance of cardiac surgery in patients with Andersen-Tawil syndrome. We present a case of successful cardiac surgery in a patient with Andersen-Tawil syndrome, without using cardioplegia.

  10. [Antithrombotic therapy in atrial arrhythmia].

    PubMed

    Cohen, Ariel

    2004-02-15

    The principal complication of the atrial arrythmias is the thrombo-embolic accident, notably the cerebro-vascular accident. The efficacity of the oral anticoagulants in reducing cerebro-vascular accidents has been demonstrated in numerous studies. This is significantly superior to that obtained with the anti-platelet drugs. However, the anti-vitamin K drugs (warfarin) carry a risk of serious haemorrhage of around 5% per year. This restricts the proposal of this treatment to patients with an elevated risk of vascular accidents: age, diabetes, previous cerebro-vascular accidents, and cardiac failure are the risk factors. Nevertheless, the risk of haemorrhage is responsible for an under prescription of the anticoagulants in the elderly. This explains the interest aroused by alternative therapeutics: the results of trials on ximelagatran, a direct anti-thrombin, are promising. In patients with an arrythmia, cardioversion carries a thrombo-embolic risk of around 1%. This risk is reduced by prior anticoagulant treatment. The procedure for this treatment is orientated by a trans-oesophageal echocardiogram. The incertitude of the duration of anticoagulant therapy without cardioversion calls for respect of the arrythmia. The treatment of this is limited to control of the cardiac rhythm and anticoagulant treatment.

  11. Effectiveness of Telemetry Guidelines in Predicting Clinically Significant Arrhythmias in Hospitalized Patients

    PubMed Central

    Dhillon, Sandeep K.; JosephTawil; Goldstein, Baruch; Eslava-Manchego, Dayana; Singh, Jagdeep; Hanon, Sam; Schweitzer, Paul; Bergmann, Steven R.

    2012-01-01

    Background Cardiac rhythm monitoring is widely applied on hospitalized patients. However, its value has not been evaluated systematically. Methods This study considered the utility of our institutional telemetry guidelines in predicting clinically significant arrhythmias. A retrospective analysis was performed of 562 patients admitted to the telemetry unit. A total of 1932 monitoring days were evaluated. Patients were divided into 2 groups based on telemetry guidelines: “telemetry indicated” and “telemetry not indicated”. Results Differences in arrhythmia event rates and pre-defined clinical significance were determined. One hundred and forty-four (34%) vs. 16 (11%) patients had at least one arrhythmic event in the “telemetry indicated” group compared with the “telemetry not indicated” group, respectively (P = 0.001). No patient in the “telemetry not indicated” group had a clinically significant arrhythmia. In contrast, of patients in the “telemetry indicated” group who had at least one arrhythmic event, 36% were considered clinically significant (P < 0.05). Conclusion In conclusion, this study validates and supports the use of our institutional telemetry guidelines to allocate this resource appropriately and predict clinically significant arrhythmias.

  12. Use of Whole Exome Sequencing for the Identification of Ito-Based Arrhythmia Mechanism and Therapy

    PubMed Central

    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

    2015-01-01

    Background 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. Methods and Results 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. Conclusions 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. PMID:26015324

  13. Potassium currents in the heart: functional roles in repolarization, arrhythmia and therapeutics.

    PubMed

    Chiamvimonvat, Nipavan; Chen-Izu, Ye; Clancy, Colleen E; Deschenes, Isabelle; Dobrev, Dobromir; Heijman, Jordi; Izu, Leighton; Qu, Zhilin; Ripplinger, Crystal M; Vandenberg, Jamie I; Weiss, James N; Koren, Gideon; Banyasz, Tamas; Grandi, Eleonora; Sanguinetti, Michael C; Bers, Donald M; Nerbonne, Jeanne M

    2017-04-01

    This is the second of the two White Papers from the fourth UC Davis Cardiovascular Symposium Systems Approach to Understanding Cardiac Excitation-Contraction Coupling and Arrhythmias (3-4 March 2016), a biennial event that brings together leading experts in different fields of cardiovascular research. The theme of the 2016 symposium was 'K(+) channels and regulation', and the objectives of the conference were severalfold: (1) to identify current knowledge gaps; (2) to understand what may go wrong in the diseased heart and why; (3) to identify possible novel therapeutic targets; and (4) to further the development of systems biology approaches to decipher the molecular mechanisms and treatment of cardiac arrhythmias. The sessions of the Symposium focusing on the functional roles of the cardiac K(+) channel in health and disease, as well as K(+) channels as therapeutic targets, were contributed by Ye Chen-Izu, Gideon Koren, James Weiss, David Paterson, David Christini, Dobromir Dobrev, Jordi Heijman, Thomas O'Hara, Crystal Ripplinger, Zhilin Qu, Jamie Vandenberg, Colleen Clancy, Isabelle Deschenes, Leighton Izu, Tamas Banyasz, Andras Varro, Heike Wulff, Eleonora Grandi, Michael Sanguinetti, Donald Bers, Jeanne Nerbonne and Nipavan Chiamvimonvat as speakers and panel discussants. This article summarizes state-of-the-art knowledge and controversies on the functional roles of cardiac K(+) channels in normal and diseased heart. We endeavour to integrate current knowledge at multiple scales, from the single cell to the whole organ levels, and from both experimental and computational studies.

  14. Modulation of respiratory sinus arrhythmia in rats with central pattern generator hardware.

    PubMed

    Nogaret, Alain; Zhao, Le; Moraes, Davi J A; Paton, Julian F R

    2013-01-15

    We report on the modulation of respiratory sinus arrhythmia in rats with central pattern generator (CPG) hardware made of silicon neurons. The neurons are made to compete through mutually inhibitory synapses to provide timed electrical oscillations that stimulate the peripheral end of vagus nerve at specific points of the respiratory cycle: the inspiratory phase (φ(1)), the early expiratory phase (φ(2)) and the late expiratory phase (φ(3)). In this way the CPG hardware mimics the neuron populations in the brainstem which through connections with cardiac vagal motoneurones control respiratory sinus arrhythmia (RSA). Here, we time the output of the CPG hardware from the phrenic nerve activity recorded from rats while monitoring heart rate changes evoked by vagal nerve stimulation (derived from ECG) controlled by the CPG. This neuroelectric stimulation has the effect of reducing the heart rate and increasing the arterial pressure. The artificially induced RSA strongly depends on the timing of pulses within the breathing cycle. It is strongest when the vagus nerve is stimulated during the inspiratory phase (φ(1)) or the early expiratory phase (φ(2)) in which case the heart rate slows by 50% of the normal rate. Heart rate modulation is less when the same exact stimulus is applied during the late expiratory phase (φ(3)). These trials show that neurostimulation by CPG hardware can augment respiratory sinus arrhythmia. The CPG hardware technology opens a new line of therapeutic possibilities for prosthetic devices that restore RSA in patients where respiratory-cardiac coupling has been lost.

  15. Benchmarking ventricular arrhythmias in the mouse--revisiting the 'Lambeth Conventions' 20 years on.

    PubMed

    Huggins, Catherine E; Bell, James R; Pepe, Salvatore; Delbridge, Lea M D

    2008-12-01

    The isolated Langendorff-mode perfused heart has become a valuable experimental model, used extensively to examine cardiac function, pathophysiology and pharmacology. For the clinical cardiologist an ECG is often a simple practicality, however in experimental circumstances, particularly with ex vivo murine hearts it is not always possible to obtain an ECG due to experimental recording constraints. However, the mechanical record of ventricular contractile function can be highly informative in relation to electrical state. It is difficult though to achieve consistency in these evaluations of arrhythmia as a validated common reference framework is lacking. In 1988, a group of investigators developed the 'Lambeth Conventions'--a standardised reference for the definition and classification of arrhythmias in animal experimental models of ischaemia, infarction and reperfusion in vivo. Now, two decades later it is timely to revisit the Lambeth Conventions, and to update the guidelines in the context of the marked increase in murine heart study in experimental cardiac pathophysiology. Here we describe an adjunct to the Lambeth Conventions for the reporting of ventricular arrhythmias post-ischaemia in ex vivo mouse hearts when ECG recordings are not employed. Of seven discrete and identifiable patterns of mechanical dysrhythmia observed in reperfusion, five could be classified using conventional ECG terminology: ventricular premature beat, bigeminy, trigeminy, ventricular tachycardia and ventricular fibrillation. Two additional rhythm variations detected from the pressure record are described (potentiated contraction and alternans).

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

    PubMed

    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.

  17. [Effect of anti-arrhythmia drugs on mouse arrhythmia induced by Bufonis Venenum].

    PubMed

    Lu, Wen-juan; Zhou, Jing; Ma, Hong-yue; Lü, Gao-hong; You, Fen-qiang; Ding, An-wei; Duan, Jin-ao

    2011-10-01

    This study is to investigate the effects of phenytoin sodium, lidocaine (sodium channel blockers), propranolol (beta-adrenergic receptor antagonist), amiodarone (drugs prolonging the action potential duration) and verapamil (calcium channel blockers) on arrhythmia of mice induced by Bufonis Venenum (Chansu) and isolated mouse hearts lethal dose of Chansu. Arrhythmia of mice were induced by Chansu and then electrocardiograms (ECGs) were recorded. The changes of P-R interval, QRS complex, Q-T interval, T wave amplitude, heart rate (HR) were observed. Moreover, arrhythmia rate, survival rate and arrhythmia score were counted. Isolated mouse hearts were prefused, and the lethal dose of Chansu was recorded. Compared with control group, after pretreatment with phenytoin sodium, broadening of QRS complex and HR were inhibited, and the incidence of ventricular arrhythmia was reduced dramatically, while survival rate was improved; the isolated mouse hearts lethal dose of Chansu was increased significantly. After pretreatment with lidocaine, the prolongation of P-R interval and broadening of QRS complex were inhibited, and the incidences of ventricular arrhythmia were reduced dramatically, while survival rate was improved; the isolated mouse hearts lethal dose of Chansu was increased significantly. After pretreatment with propranolol, prolongation of P-R interval, broadening of QRS complex, prolongation of Q-T interval and HR were inhibited, and the incidences of both supraventricular and ventricular arrhythmias were reduced dramatically, while survival rate was improved. After pretreatment with amiodarone, HR was inhibited, the incidences of ventricular tachycardia were reduced dramatically. Lastly, after pretreatment with verapamil, the prolongation of P-R interval and Q-T interval were inhibited and the incidences of both supraventricular and ventricular arrhythmias were reduced dramatically; the isolated mouse hearts lethal dose of Chansu was reduced significantly. In in

  18. Is there a synergic effect of propafenone associated with atrial overdrive pacing for atrial arrhythmia prevention? A randomised crossover study

    PubMed Central

    Garrigue, S; Barold, S; Cazeau, S; Hocini, M; Jais, P; Haissaguerre, M; Clementy, J

    2000-01-01

    with atrial overdrive alone.
CONCLUSIONS—In DDD paced patients, the overall effect of propafenone during atrial overdrive is variable. Propafenone may increase the proportion of asymptomatic atrial arrhythmia episodes. A proarrhythmic effect of propafenone was documented (aggravation of atrial arrhythmias). These results need to be confirmed by further larger randomised studies.


Keywords: dual chamber pacing; atrial overdrive pacing; atrial arrhythmia; propafenone PMID:10648490

  19. [Sudden cardiac death in individuals with normal hearts: an update].

    PubMed

    González-Melchor, Laila; Villarreal-Molina, Teresa; Iturralde-Torres, Pedro; Medeiros-Domingo, Argelia

    2014-01-01

    Sudden death (SD) is a tragic event and a world-wide health problem. Every year, near 4-5 million people experience SD. SD is defined as the death occurred in 1h after the onset of symptoms in a person without previous signs of fatality. It can be named "recovered SD" when the case received medical attention, cardiac reanimation effective defibrillation or both, surviving the fatal arrhythmia. Cardiac channelopathies are a group of diseases characterized by abnormal ion channel function due to genetic mutations in ion channel genes, providing increased susceptibility to develop cardiac arrhythmias and SD. Usually the death occurs before 40 years of age and in the autopsy the heart is normal. In this review we discuss the main cardiac channelopathies involved in sudden cardiac death along with current management of cases and family members that have experienced such tragic event.

  20. Determining conduction patterns on a sparse electrode grid: Implications for the analysis of clinical arrhythmias

    NASA Astrophysics Data System (ADS)

    Vidmar, David; Narayan, Sanjiv M.; Krummen, David E.; Rappel, Wouter-Jan

    2016-11-01

    We present a general method of utilizing bioelectric recordings from a spatially sparse electrode grid to compute a dynamic vector field describing the underlying propagation of electrical activity. This vector field, termed the wave-front flow field, permits quantitative analysis of the magnitude of rotational activity (vorticity) and focal activity (divergence) at each spatial point. We apply this method to signals recorded during arrhythmias in human atria and ventricles using a multipolar contact catheter and show that the flow fields correlate with corresponding activation maps. Further, regions of elevated vorticity and divergence correspond to sites identified as clinically significant rotors and focal sources where therapeutic intervention can be effective. These flow fields can provide quantitative insights into the dynamics of normal and abnormal conduction in humans and could potentially be used to enhance therapies for cardiac arrhythmias.

  1. Enhanced self-termination of re-entrant arrhythmias as a pharmacological strategy for antiarrhythmic action

    NASA Astrophysics Data System (ADS)

    Aslanidi, O. V.; Bailey, A.; Biktashev, V. N.; Clayton, R. H.; Holden, A. V.

    2002-09-01

    Ventricular tachycardia and fibrillation are potentially lethal cardiac arrhythmias generated by high frequency, irregular spatio-temporal electrical activity. Re-entrant propagation has been demonstrated as a mechanism generating these arrhythmias in computational and in vitro animal models of these arrhythmias. Re-entry can be idealised in homogenous isotropic virtual cardiac tissues as spiral and scroll wave solutions of reaction-diffusion equations. A spiral wave in a bounded medium can be terminated if its core reaches a boundary. Ventricular tachyarrhythmias in patients are sometimes observed to spontaneously self-terminate. One possible mechanism for self-termination of a spiral wave is meander of its core to an inexcitable boundary. We have previously proposed the hypothesis that the spatial extent of meander of a re-entrant wave in the heart can be directly related to its probability of self-termination, and so inversely related to its lethality. Meander in two-dimensional virtual ventricular tissues based on the Oxsoft family of cell models, with membrane excitation parameters simulating the inherited long Q-T syndromes has been shown to be consistent with this hypothesis: the largest meander is seen in the syndrome with the lowest probability of death per arrhythmic episode. Here we extend our previous results to virtual tissues based on the Luo-Rudy family of models. Consistent with our hypothesis, for both families of models, whose different ionic mechanisms produce different patterns of meander, the LQT virtual tissue with the larger meander simulates the syndrome with the lower probability of death per episode. Further, we search the parameter space of the repolarizing currents to find their conductance parameter values that give increased meander of spiral waves. These parameters may provide targets for antiarrhythmic drugs designed to act by increasing the likelihood of self-termination of re-entrant arrhythmias.

  2. Role of angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, and aldosterone antagonists in the prevention of atrial and ventricular arrhythmias.

    PubMed

    Makkar, Kathy M; Sanoski, Cynthia A; Spinler, Sarah A

    2009-01-01

    Atrial arrhythmias, ventricular arrhythmias, and sudden cardiac death (SCD) are significant health problems and an economic burden to society. The renin-angiotensin-aldosterone system (RAAS) may play a key role in the occurrence of structural and electrical remodeling, potentially explaining the development of atrial and ventricular arrhythmias. Angiotensin II has been shown to regulate cardiac cell proliferation and to modulate cardiac myocyte ion channels. Results of post hoc analyses from prospective clinical trials appear to show that angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) are most effective in the prevention of new-onset atrial fibrillation in patients with heart failure. It is difficult to determine if these agents are useful in the prevention of new-onset atrial fibrillation after myocardial infarction, and available evidence suggests that the benefit of ACE inhibitors and ARBs for prevention of new-onset atrial fibrillation in patients with hypertension appears limited to those with left ventricular hypertrophy. Patients with structural changes in cardiac muscle, such as those with heart failure and left ventricular hypertrophy, appear to benefit the most from RAAS blockade, possibly due to the theory of reversal of cardiac remodeling. There is no evidence, to our knowledge, that either ACE inhibitors or ARBs facilitate direct electrical current cardioversion in patients with atrial fibrillation; however, it appears that RAAS blockade may be useful in the prevention of recurrent atrial fibrillation after direct electrical current cardioversion. Whether ACE inhibitors may prevent life-threatening ventricular arrhythmias or SCD is unclear. Aldosterone antagonists appear to be useful for the prevention of SCD in patients with left ventricular systolic dysfunction. Results from ongoing clinical trials are anticipated to provide further insight on the potential roles of RAAS inhibitors for the prevention of

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

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

    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.

  4. Exploring susceptibility to atrial and ventricular arrhythmias resulting from remodeling of the passive electrical properties in the heart: a simulation approach

    PubMed Central

    Trayanova, Natalia A.; Boyle, Patrick M.; Arevalo, Hermenegild J.; Zahid, Sohail

    2014-01-01

    Under diseased conditions, remodeling of the cardiac tissue properties (“passive properties”) takes place; these are aspects of electrophysiological behavior that are not associated with active ion transport across cell membranes. Remodeling of the passive electrophysiological properties most often results from structural remodeling, such as gap junction down-regulation and lateralization, fibrotic growth infiltrating the myocardium, or the development of an infarct scar. Such structural remodeling renders atrial or ventricular tissue as a major substrate for arrhythmias. The current review focuses on these aspects of cardiac arrhythmogenesis. Due to the inherent complexity of cardiac arrhythmias, computer simulations have provided means to elucidate interactions pertinent to this spatial scale. Here we review the current state-of-the-art in modeling atrial and ventricular arrhythmogenesis as arising from the disease-induced changes in the passive tissue properties, as well as the contributions these modeling studies have made to our understanding of the mechanisms of arrhythmias in the heart. Because of the rapid advance of structural imaging methodologies in cardiac electrophysiology, we chose to present studies that have used such imaging methodologies to construct geometrically realistic models of cardiac tissue, or the organ itself, where the regional remodeling properties of the myocardium can be represented in a realistic way. We emphasize how the acquired knowledge can be used to pave the way for clinical applications of cardiac organ modeling under the conditions of structural remodeling. PMID:25429272

  5. Hemodynamic effects of encainide in patients with ventricular arrhythmia and poor ventricular function

    SciTech Connect

    Sami, M.H.; Derbekyan, V.A.; Lisbona, R.

    1983-09-01

    Gated cardiac scanning was used to evaluate the hemodynamic effects of encainide in 19 patients (1 woman) with complex ventricular arrhythmia and depressed left ventricular (LV) function (ejection fraction less than 45%). Patients were 36 to 80 years old (average 61). All were candidates for long-term encainide therapy after having failed with currently available antiarrhythmics. Sixty-three percent had congestive heart failure before they received encainide. All were evaluated in the hospital before encainide therapy by a gated cardiac scan performed at least 3 days after discontinuing all antiarrhythmic drugs. Patients received oral encainide in doses of 75 to 200 mg. Gated cardiac scans were repeated 1 to 2 weeks later when an 80% reduction in frequency of premature ventricular complexes was observed on a 24-hour Holter recording. No patient had worsening of congestive heart failure during encainide therapy. Encainide did not significantly affect ejection fraction, which averaged 22 +/- 10% before and 25 +/- 14% (SD) after encainide (difference not significant (NS)). Other hemodynamic variables, including heart rate, blood pressure, stroke volume and end-diastolic volume, remained unchanged during encainide therapy. Digoxin blood levels in 10 patients averaged 1.04 +/- 0.43 before and 1.22 +/- 0.47 mg/ml (NS) during encainide therapy. Thus, encainide given orally in clinically effective doses does not appear to have significant hemodynamic effects in patients with ventricular arrhythmia and depressed LV function.

  6. Zebrafish heart as a model for human cardiac electrophysiology.

    PubMed

    Vornanen, Matti; Hassinen, Minna

    2016-01-01

    The zebrafish (Danio rerio) has become a popular model for human cardiac diseases and pharmacology including cardiac arrhythmias and its electrophysiological basis. Notably, the phenotype of zebrafish cardiac action potential is similar to the human cardiac action potential in that both have a long plateau phase. Also the major inward and outward current systems are qualitatively similar in zebrafish and human hearts. However, there are also significant differences in ionic current composition between human and zebrafish hearts, and the molecular basis and pharmacological properties of human and zebrafish cardiac ionic currents differ in several ways. Cardiac ionic currents may be produced by non-orthologous genes in zebrafish and humans, and paralogous gene products of some ion channels are expressed in the zebrafish heart. More research on molecular basis of cardiac ion channels, and regulation and drug sensitivity of the cardiac ionic currents are needed to enable rational use of the zebrafish heart as an electrophysiological model for the human heart.

  7. Robotic magnetic navigation for ablation of human arrhythmias

    PubMed Central

    Da Costa, Antoine; Guichard, Jean Baptiste; Roméyer-Bouchard, Cécile; Gerbay, Antoine; Isaaz, Karl

    2016-01-01

    Radiofrequency treatment represents the first choice of treatment for arrhythmias, in particular complex arrhythmias and especially atrial fibrillation, due to the greater benefit/risk ratio compared to antiarrhythmic drugs. However, complex arrhythmias such as atrial fibrillation require long procedures with additional risks such as X-ray exposure or serious complications such as tamponade. Given this context, the treatment of arrhythmias using robotic magnetic navigation entails a technique well suited to complex arrhythmias on account of its efficacy, reliability, significant reduction in X-ray exposure for both patient and operator, as well as a very low risk of perforation. As ongoing developments will likely improve results and procedure times, this technology will become one of the most modern technologies for treating arrhythmias. Based on the literature, this review summarizes the advantages and limitations of robotic magnetic navigation for ablation of human arrhythmias. PMID:27698569

  8. The U-shaped relationship between exercise and cardiac morbidity.

    PubMed

    Merghani, Ahmed; Malhotra, Aneil; Sharma, Sanjay

    2016-04-01

    Exercise confers a plethora of health benefits that are well documented, whereas physical inactivity is a leading risk factor for cardiovascular morbidity and mortality. The dose of physical activity required to achieve these benefits is relatively modest and equates to jogging at a pace of 15min per mile for 20-30min daily. In the current era, most athletes engage in a volume and intensity of exercise that is at least 5-10-fold greater than the general recommendations for physical activity. Such practice is evidenced by the fact that many sportsmen have achieved athletic feats that were considered impossible only 2 decades ago. Numerous studies in retired athletes have consistently shown a reduced incidence of heart disease and an increased longevity of life. Occasionally, however, intense exercise is associated with sudden deaths in athletes harboring quiescent yet potentially sinister cardiac diseases. Despite the visibility afforded by such catastrophes, the reputation of exercise remains unscathed because most deaths can be accounted for by an underlying cardiac abnormality where exercise is a mere trigger for a fatal arrhythmia rather than the actual cause of death. More recently, there have been an emerging number of reports suggesting that intense exercise may have an adverse impact on an otherwise normal heart. This article will review the morbidity and mortality associated with sport and pose the question whether one can have "too much of a good thing."

  9. Increased Nonconducted P-Wave Arrhythmias after a Single Oil Fly Ash Inhalation Exposure in Hypertensive Rats

    PubMed Central

    Farraj, Aimen K.; Haykal-Coates, Najwa; Winsett, Darrell W.; Hazari, Mehdi S.; Carll, Alex P.; Rowan, William H.; Ledbetter, Allen D.; Cascio, Wayne E.; Costa, Daniel L.

    2009-01-01

    Background Exposure to combustion-derived fine particulate matter (PM) is associated with increased cardiovascular morbidity and mortality especially in individuals with cardiovascular disease, including hypertension. PM inhalation causes several adverse changes in cardiac function that are reflected in the electrocardiogram (ECG), including altered cardiac rhythm, myocardial ischemia, and reduced heart rate variability (HRV). The sensitivity and reliability of ECG-derived parameters as indicators of the cardiovascular toxicity of PM in rats are unclear. Objective We hypothesized that spontaneously hypertensive (SH) rats are more susceptible to the development of PM-induced arrhythmia, altered ECG morphology, and reduced HRV than are Wistar Kyoto (WKY) rats, a related strain with normal blood pressure. Methods We exposed rats once by nose-only inhalation for 4 hr to residual oil fly ash (ROFA), an emission source particle rich in transition metals, or to air and then sacrificed them 1 or 48 hr later. Results ROFA-exposed SH rats developed nonconducted P-wave arrhythmias but no changes in ECG morphology or HRV. We found no ECG effects in ROFA-exposed WKY rats. ROFA-exposed SH rats also had greater pulmonary injury, neutrophil infiltration, and serum C-reactive protein than did ROFA-exposed WKY rats. Conclusions These results suggest that cardiac arrhythmias may be an early sensitive indicator of the propensity for PM inhalation to modify cardiovascular function. PMID:19479011

  10. POPDC1S201F causes muscular dystrophy and arrhythmia by affecting protein trafficking

    PubMed Central

    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

  11. Role of Genetic Testing in Patients with Ventricular Arrhythmias in Apparently Normal Hearts.

    PubMed

    Hofman, Nynke; Wilde, Arthur A M

    2016-09-01

    Ventricular arrhythmias without structural heart disease are responsible for ∼35% of patients who have sudden cardiac death before the age of 40 years. Molecular autopsy and/or cardiological investigation of nearby family members often reveals the diagnosis and genetic testing can be helpful in family screening and risk stratification in disease carriers. Extended gene panels can be screened in a short period of time at low cost. A multidisciplinary team of (genetically) specialized clinicians is necessary to judge all the available details and to decide on the significance of the variant and further strategies.

  12. Effectiveness of morphological and spectral heartbeat characterization on arrhythmia clustering for Holter recordings

    NASA Astrophysics Data System (ADS)

    Castro-Hoyos, Cristian; Peluffo-Ordóñez, Diego Hernán.; Rodríguez-Sotelo, Jose Luis; Castellanos-Domínguez, Germán.

    2015-01-01

    Heartbeat characterization is an important issue in cardiac assistance diagnosis systems. In particular, wide sets of features are commonly used in long term electrocardiographic signals. Then, if such a feature space does not represent properly the arrhythmias to be grouped, classification or clustering process may fail. In this work a suitable feature set for different heartbeat types is studied, involving morphology, representation and time-frequency features. To determine what kind of features generate better clusters, feature selection procedure is used and assessed by means clustering validity measures. Then the feature subset is shown to produce fine clustering that yields into high sensitivity and specificity values for a broad range of heartbeat types.

  13. Haemodynamic assessment of fetal heart arrhythmias.

    PubMed

    Lingman, G; Dahlström, J A; Eik-Nes, S H; Marsál, K; Ohlin, P; Ohrlander, S

    1984-07-01

    The effects of fetal heart arrhythmias were examined serially in two pregnancies by three non-invasive methods: fetal ECG, fetal phonocardiography and ultrasonic measurement of fetal blood flow. In a case of supraventricular arrhythmia, there was evidence suggesting that the stroke volume varied with ventricular filling according to the Frank-Starling law. In a case of total atrioventricular block the mean blood flow in the fetal descending aorta and in the umbilical vein was within the normal range. Blood flow velocity in the inferior vena cava of the fetus reflected atrial contractions. In the phonocardiogram, a phenomenon similar to 'bruit de canon' was found. Both pregnancies had good outcomes and subsequent development of the infants was normal except for the persisting dysrhythmias. The two cases exemplify how fetal heart function can be assessed in utero.

  14. [Compromized myocardial perfusion in arrhythmias (author's transl)].

    PubMed

    Simon, H; Neumann, G; Felix, R; Hedde, H; Schaede, A; Thurn, P; Winkler, C

    1977-09-15

    In 7 patients with arrhythmias of various origin the myocardial scintigram displayed either a diffuse or circumscript defect of the perfusion. The coronary arteriogram was normal in all patients. The localized defect of the perfusion in 2 patients was in the region of the upper part of the interventricular septum. Both had a left bundle brunch block. A correlation between the perfusion defect and the electrophysiological abnormality seems probable. The perfusion defect in one of the patients is most probably caused by a previous myocarditis followed by fibrous changes. In the other 6 patients the cause for the perfusion defect is not obvious. A history of myocarditis is missing. The presence of "small vessel disease" in those patients has however to be considered. Our results point to the relation between an abnormality of the microcirculation and arrhythmias in younger patients.

  15. Progressive interatrial block and supraventricular arrhythmias.

    PubMed

    Enriquez, Andres; Conde, Diego; Redfearn, Damian P; Baranchuk, Adrian

    2015-07-01

    Interatrial conduction disorders are frequent in patients with structural heart diseases, including hypertension, coronary disease, and hypertrophic cardiomyopathy, and they are strongly associated with atrial tachyarrhythmias, especially atrial fibrillation and flutter. Conduction delays lead to dispersion of refractory periods and participate in initiating and maintaining reentry circuits, facilitating atrial arrhythmias. In this case, the changing pattern over time is a manifestation of progressive atrial remodeling and conduction delay. The terminal negative component of the P wave in the inferior leads suggests block of the electrical impulse in the Bachman bundle zone, with retrograde activation of the left atria via muscular connections at the coronary sinus. This has been reproduced in experimental models and confirmed by endocardial mapping. Physicians should be aware of the association between advanced interatrial block and development of atrial arrhythmias as its recognition could prompt early and aggressive antiarrhythmic treatment.

  16. Asymptomatic cardiac rhabdomyoma in neonates: is surgery indicated?

    PubMed Central

    Etuwewe, B; John, CM; Abdelaziz, M

    2009-01-01

    Background Neonatal Tuberose sclerosis complex may be associated with symptomatic cardiac rhabdomyomas. Cardiac rhabdomyomas are the most common cardiac tumours. The symptoms include haemodynamic instability and life threatening arrhythmias usually requiring early surgical intervention. Results We report a case of a 32 week gestation newborn diagnosed with a right ventricular outflow tract mass and subsequently diagnosed with tuberose sclerosis that needed early surgical intervention. Conclusion While this case needed early intervention, the need for surgical intervention in otherwise asymptomatic cases is debatable as neonatal cardiac rhabdomyomas can spontaneously regress. PMID:22368553

  17. Ultrasound in cardiac trauma.

    PubMed

    Saranteas, Theodosios; Mavrogenis, Andreas F; Mandila, Christina; Poularas, John; Panou, Fotios

    2017-04-01

    In the perioperative period, the emergency department or the intensive care unit accurate assessment of variable chest pain requires meticulous knowledge, diagnostic skills, and suitable usage of various diagnostic modalities. In addition, in polytrauma patients, cardiac injury including aortic dissection, pulmonary embolism, acute myocardial infarction, and pericardial effusion should be immediately revealed and treated. In these patients, arrhythmias, mainly tachycardia, cardiac murmurs, or hypotension must alert physicians to suspect cardiovascular trauma, which would potentially be life threatening. Ultrasound of the heart using transthoracic and transesophageal echocardiography are valuable diagnostic tools that can be used interchangeably in conjunction with other modalities such as the electrocardiogram and computed tomography for the diagnosis of cardiovascular abnormalities in trauma patients. Although ultrasound of the heart is often underused in the setting of trauma, it does have the advantages of being easily accessible, noninvasive, and rapid bedside assessment tool. This review article aims to analyze the potential cardiac injuries in trauma patients, and to provide an elaborate description of the role of echocardiography for their accurate diagnosis.

  18. Malignant ventricular arrhythmias in chronic chagasic myocarditis.

    PubMed

    Chiale, P A; Halpern, M S; Nau, G J; Przybylski, J; Tambussi, A M; Lázzari, J O; Elizari, M V; Rosenbaum, M B

    1982-03-01

    We studied 28 cases of chronic chagasic myocarditis (CCM) with frequent ventricular arrhythmias. Two-hundred and three conventional ECGs recorded during 3 months showed ventricular extrasystoles (VE) ranging between 0.2 and 6 per ten beats in 100%; multiform VE in 97.04%; couplets in 79.31%; ventricular tachycardia (VT) in 42.85%; and R on T in 21.67%. A 24-hour continuous recording showed that VE ranged between 3780 and 61733 (mean 16618 +/- 2627); multiform VE and couplets were present in 100% of patients, and VT was present in 78.5%. In 16 patients (group I) the frequency of VE was persistently high, without diurnal variation; 11 patients showed sustained reduction during sleeping hours and only one showed an increase during night sleep (group II). Even in group II, VE never disappeared for periods longer than 10 minutes. In five patients, four 24-hour recordings were obtained at weekly intervals, and in five other patients a second 24-hour recording was performed 10 to 24 months later. The remarkable frequency, persistence and low variability of ventricular arrhythmias in CCM suggest that such arrhythmias can be used as a most stable, reliable, but highly demanding model for testing the efficacy of antiarrhythmic drugs.

  19. e-Health prototype system for cardiac telemonitoring.

    PubMed

    Vargas Escobar, Laura Juliana; Salinas, Sergio Alexander

    2016-08-01

    This paper presents the approach of an e-health system for cardiac telemonitoring which uses the development board LinkIt ONE as a monitoring system. Such board was adapted to measure the cardiac pulse, analyze it and determine whether a person is having a cardiac arrhythmia or not. When an arrhythmia appears, the prototype activates an alarm in order to report the patient's condition and its location to a caregiver or a close healthcare center. The data of the cardiac pulse is originated in an e-health sensor platform connected to an Arduino. Location data comes from a GPS module in the aforementioned board which is connected by WiFi with the virtual platform UBIDOTS. It provides visual information about the variables measured, the patient's location and the alarms; keeping the patient's caregiver or the healthcare center constantly informed.

  20. Understand Your Risk for Cardiac Arrest

    MedlinePlus

    ... Giving for Heart.org Media for Heart.org Arrhythmia About Arrhythmia Why Arrhythmia Matters Understand Your Risk for Arrhythmia Symptoms, Diagnosis & Monitoring of Arrhythmia Prevention & Treatment of ...

  1. Pharmacology of cardiac potassium channels.

    PubMed

    Tamargo, Juan; Caballero, Ricardo; Gómez, Ricardo; Valenzuela, Carmen; Delpón, Eva

    2004-04-01

    Cardiac K+ channels are membrane-spanning proteins that allow the passive movement of K+ ions across the cell membrane along its electrochemical gradient. They regulate the resting membrane potential, the frequency of pacemaker cells and the shape and duration of the cardiac action potential. Additionally, they have been recognized as potential targets for the actions of neurotransmitters and hormones and class III antiarrhythmic drugs that prolong the action potential duration (APD) and refractoriness and have been found effective to prevent/suppress cardiac arrhythmias. In the human heart, K+ channels include voltage-gated channels, such as the rapidly activating and inactivating transient outward current (Ito1), the ultrarapid (IKur), rapid (IKr) and slow (IKs) components of the delayed rectifier current and the inward rectifier current (IK1), the ligand-gated channels, including the adenosine triphosphate-sensitive (IKATP) and the acetylcholine-activated (IKAch) currents and the leak channels. Changes in the expression of K+ channels explain the regional variations in the morphology and duration of the cardiac action potential among different cardiac regions and are influenced by heart rate, intracellular signalling pathways, drugs and cardiovascular disorders. A progressive number of cardiac and noncardiac drugs block cardiac K+ channels and can cause a marked prolongation of the action potential duration (i.e. an acquired long QT syndrome, LQTS) and a distinct polymorphic ventricular tachycardia termed torsades de pointes. In addition, mutations in the genes encoding IKr (KCNH2/KCNE2) and IKs (KCNQ1/KCNE1) channels have been identified in some types of the congenital long QT syndrome. This review concentrates on the function, molecular determinants, regulation and, particularly, on the mechanism of action of drugs modulating the K+ channels present in the sarcolemma of human cardiac myocytes that contribute to the different phases of the cardiac action

  2. Reversible cardiac conduction block and defibrillation with high-frequency electric field.

    PubMed

    Tandri, Harikrishna; Weinberg, Seth H; Chang, Kelly C; Zhu, Renjun; Trayanova, Natalia A; Tung, Leslie; Berger, Ronald D

    2011-09-28

    Electrical impulse propagation is an essential function in cardiac, skeletal muscle, and nervous tissue. Abnormalities in cardiac impulse propagation underlie lethal reentrant arrhythmias, including ventricular fibrillation. Temporary propagation block throughout the ventricular myocardium could possibly terminate these arrhythmias. Electrical stimulation has been applied to nervous tissue to cause reversible conduction block, but has not been explored sufficiently in cardiac tissue. We show that reversible propagation block can be achieved in cardiac tissue by holding myocardial cells in a refractory state for a designated period of time by applying a sustained sinusoidal high-frequency alternating current (HFAC); in doing so, reentrant arrhythmias are terminated. We demonstrate proof of concept using several models, including optically mapped monolayers of neonatal rat ventricular cardiomyocytes, Langendorff-perfused guinea pig and rabbit hearts, intact anesthetized adult rabbits, and computer simulations of whole-heart impulse propagation. HFAC may be an effective and potentially safer alternative to direct current application, currently used to treat ventricular fibrillation.

  3. Mechanism of escape, extrasystolic, and parasystolic arrhythmias. Study on an electrical analogue.

    PubMed

    Sideris, D A

    1976-01-01

    A simple analogue of the heart consisting of a system of neon relaxation oscillators is presented. The analogue may display rhythm patterns similar to sinus rhythm, escape rhythm, isorrhythmic dissociation with synchronization, atrial extrasystoles, ventricular extrasystoles, and parasystole. The strict rules followed by these arrhythmias, as well as the deviations from the rules commonly followed by the equivalent heart arrhythmias, may be easily reproduced on the analogue. Such features are the Treppe phenomenon and captured beats in escape rhythm, fixed coupling intervals in extrasystoles, partial or complete atrioventricular block in very premature atrial extrasystoles, prolongation of the period following an atrial extrasystole, interpolated premature beats, complete compensatory pause and the rule of bigeminy in ventricular extrasystoles, slight instability of the parasystolic period, multiple length parasystolic periods slightly different from the exact multiples of the parasystolic idioperiod, preference of the parasystoles for certain phase in the sinus cycle, synchronization at a phase difference and fluctuation repeatedly and without interruption from a parasystolic to an extrasystolic rhythm and synchronization in escape rhythm with isorrhythmic dissociation. The mechanisms involved in these phenomena are discussed in detail. The striking similarity between the properties of the cardiac pacemakers and those of the relaxation oscillators on the one hand and betwen the rhythm patterns of the heart and those of the analogue on the other may permit the hypothesis that the mechanisms operating in the analogue may be used in analyzing and understanding heart arrhythmias.

  4. Arrhythmias in athletes: evidence-based strategies and challenges for diagnosis, management, and sports eligibility.

    PubMed

    Fragakis, Nikolaos; Pagourelias, Efstathios D; Koskinas, Konstantinos C; Vassilikos, Vassilios

    2013-01-01

    Assessment and management of cardiac rhythm disorders in athletes is particularly challenging. An accurate diagnosis and optimal risk-stratification are often limited because of substantial phenotypic overlap between pathological entities and adaptive cardiovascular responses that normally occur in athletes. An accurate diagnosis, however, is particularly important in this population, as 2 competing risks need to be cautiously balanced: the risk of under-diagnosis of an arrhythmogenic substrate that may trigger life-threatening events versus the risk of over-diagnosis that may result in an athlete's improper disqualification. Accordingly, the management of arrhythmias in athletes may pose therapeutic dilemmas, and often differs substantially compared with the general population. In this review, we present the most frequently observed arrhythmias in athletes and briefly discuss their pathophysiologic substrate. We further propose diagnostic and therapeutic strategies based upon current guidelines, official recommendations, and emerging evidence from relevant clinical investigations. We focus particularly on disparities in current guidelines regarding the management of certain rhythm disorders, as these areas of uncertainty may reflect the challenging nature of these disorders and may indicate the need for individualized approaches in every-day clinical practice. A better understanding of the normal electrophysiological responses to chronic exercise, and of the pathophysiological basis and the true clinical significance of arrhythmias in athletes, may enhance decision-making, and may allow for management strategies which more prudently weigh the risk-to-benefit ratio of each approach.

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

    PubMed Central

    Li, Hongqiang; Yuan, Danyang; Wang, Youxi; Cui, Dianyin; Cao, Lu

    2016-01-01

    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. PMID:27775596

  6. A novel algorithm for ventricular arrhythmia classification using a fuzzy logic approach.

    PubMed

    Weixin, Nong

    2016-12-01

    In the present study, it has been shown that an unnecessary implantable cardioverter-defibrillator (ICD) shock is often delivered to patients with an ambiguous ECG rhythm in the overlap zone between ventricular tachycardia (VT) and ventricular fibrillation (VF); these shocks significantly increase mortality. Therefore, accurate classification of the arrhythmia into VT, organized VF (OVF) or disorganized VF (DVF) is crucial to assist ICDs to deliver appropriate therapy. A classification algorithm using a fuzzy logic classifier was developed for accurately classifying the arrhythmias into VT, OVF or DVF. Compared with other studies, our method aims to combine ten ECG detectors that are calculated in the time domain and the frequency domain in addition to different levels of complexity for detecting subtle structure differences between VT, OVF and DVF. The classification in the overlap zone between VT and VF is refined by this study to avoid ambiguous identification. The present method was trained and tested using public ECG signal databases. A two-level classification was performed to first detect VT with an accuracy of 92.6 %, and then the discrimination between OVF and DVF was detected with an accuracy of 84.5 %. The validation results indicate that the proposed method has superior performance in identifying the organization level between the three types of arrhythmias (VT, OVF and DVF) and is promising for improving the appropriate therapy choice and decreasing the possibility of sudden cardiac death.

  7. The Brugada Syndrome: A Rare Arrhythmia Disorder with Complex Inheritance.

    PubMed

    Gourraud, Jean-Baptiste; Barc, Julien; Thollet, Aurélie; Le Scouarnec, Solena; Le Marec, Hervé; Schott, Jean-Jacques; Redon, Richard; Probst, Vincent

    2016-01-01

    For the last 10 years, applying new sequencing technologies to thousands of whole exomes has revealed the high variability of the human genome. Extreme caution should thus be taken to avoid misinterpretation when associating rare genetic variants to disease susceptibility. The Brugada syndrome (BrS) is a rare inherited arrhythmia disease associated with high risk of sudden cardiac death in the young adult. Familial inheritance has long been described as Mendelian, with autosomal dominant mode of transmission and incomplete penetrance. However, all except 1 of the 23 genes previously associated with the disease have been identified through a candidate gene approach. To date, only rare coding variants in the SCN5A gene have been significantly associated with the syndrome. However, the genotype/phenotype studies conducted in families with SCN5A mutations illustrate the complex mode of inheritance of BrS. This genetic complexity has recently been confirmed by the identification of common polymorphic alleles strongly associated with disease risk. The implication of both rare and common variants in BrS susceptibility implies that one should first define a proper genetic model for BrS predisposition prior to applying molecular diagnosis. Although long remains the way to personalized medicine against BrS, the high phenotype variability encountered in familial forms of the disease may partly find an explanation into this specific genetic architecture.

  8. Beyond pure parasystole: promises and problems in modeling complex arrhythmias.

    PubMed

    Courtemanche, M; Glass, L; Rosengarten, M D; Goldberger, A L

    1989-08-01

    The dynamics of pure parasystole, a cardiac arrhythmia in which two competing pacemakers fire independently, have recently been fully characterized. This model is now extended in an attempt to account for the more complex dynamics occurring with modulated parasystole, in which there exists nonlinear interaction between the sinus node and the ectopic ventricular focus. Theoretical analysis of modulated parasystole reveals three types of dynamics: entrainment, quasiperiodicity, and chaos. Rhythms associated with quasiperiodicity obey a set of rules derived from pure parasystole. This model is applied to the interpretation of continuous electrocardiographic data sets from three patients with complicated patterns of ventricular ectopic activity. We describe several new statistical properties of these records, related to the number of intervening sinus beats between ectopic events, that are essential in characterizing the dynamics and testing mathematical models. Detailed comparison between data and theory in these cases show substantial areas of agreement as well as potentially important discrepancies. These findings have implications for understanding the dynamics of the heartbeat in normal and pathological conditions.

  9. Use of cardiac glycosides and risk of glioma.

    PubMed

    Seliger, Corinna; Meier, Christoph R; Jick, Susan S; Uhl, Martin; Bogdahn, Ulrich; Hau, Peter; Leitzmann, M F

    2016-04-01

    Cardiac glycosides induce apoptotic effects on glioma cells, but whether cardiac glycosides protect against risk for glioma is unknown. We therefore explored the relation between glycoside use and glioma risk using a large and validated database. We performed a case-control analysis using the Clinical Practice Research Datalink involving 2005 glioma cases diagnosed between 1995 and 2012 that were individually matched to 20,050 controls on age, gender, general practice, and number of years of active history in the database. Conditional logistic regression analysis was used to evaluate the association between cardiac glycosides and the risk of glioma adjusting for body mass index and smoking. We also examined use of common heart failure and arrhythmia medications to differentiate between a specific glycoside effect and a generic effect of treatment for congestive heart failure or arrhythmia. Cardiac glycoside use was inversely related to glioma incidence. After adjustment for congestive heart failure, arrhythmia, diabetes, and common medications used to treat those conditions, the OR of glioma was 0.47 (95% CI 0.27-0.81, Bonferroni-corrected p value = 0.024) for use versus non-use of cardiac glycosides, based on 17 exposed cases. In contrast, no associations were noted for other medications used to treat congestive heart failure or arrhythmias. The OR of glioma in people with congestive heart failure was 0.65 (95% CI 0.40-1.04), and for arrhythmia it was 1.01 (95% CI 0.78-1.31). These data indicate that cardiac glycoside use is independently associated with reduced glioma risk.

  10. Physics of Cardiac Arrhythmogenesis

    NASA Astrophysics Data System (ADS)

    Karma, Alain

    2013-04-01

    A normal heartbeat is orchestrated by the stable propagation of an excitation wave that produces an orderly contraction. In contrast, wave turbulence in the ventricles, clinically known as ventricular fibrillation (VF), stops the heart from pumping and is lethal without prompt defibrillation. I review experimental, computational, and theoretical studies that have shed light on complex dynamical phenomena linked to the initiation, maintenance, and control of wave turbulence. I first discuss advances made to understand the precursor state to a reentrant arrhythmia where the refractory period of cardiac tissue becomes spatiotemporally disordered; this is known as an arrhythmogenic tissue substrate. I describe observed patterns of transmembrane voltage and intracellular calcium signaling that can contribute to this substrate, and symmetry breaking instabilities to explain their formation. I then survey mechanisms of wave turbulence and discuss novel methods that exploit electrical pacing stimuli to control precursor patterns and low-energy pulsed electric fields to control turbulence.

  11. Deficiency of cyclase-associated protein 2 promotes arrhythmias associated with connexin43 maldistribution and fibrosis

    PubMed Central

    Peche, Vivek Shahaji; Linhart, Markus; Nickenig, Georg; Noegel, Angelika Anna; Schrickel, Jan Wilko

    2016-01-01

    Introduction Cyclase-associated protein 2 (CAP2) plays a major role in regulating the actin cytoskeleton. Since inactivation of CAP2 in a mouse model by a gene trap approach (Cap2gt/gt) results in cardiomyopathy and increased mortality, we hypothesized that CAP2 has a major impact on arrhythmias and electrophysiological parameters. Material and methods We performed long-term-ECG recordings in transgenic CAP2 deficient mice (C57BL/6) to detect spontaneous arrhythmias. In vivo electrophysiological studies by right heart catheterization and ex vivo epicardial mapping were used to analyze electrophysiological parameters, the inducibility of arrhythmias, and conduction velocities. Expression and distribution of cardiac connexins and the amount of cardiac fibrosis were evaluated. Results Spontaneous ventricular arrhythmias could be detected in Cap2gt/gt during the long-term-ECG recording. Cap2gt/gt showed marked conduction delays at atrial and ventricular levels, including a reduced heart rate (421.0 ±40.6 bpm vs. 450.8 ±27.9 bpm; p < 0.01), and prolongations of PQ (46.3 ±4.1 ms vs. 38.6 ±6.5 ms; p < 0.01), QRS (16.2 ±2.6 ms vs. 12.6 ±1.4 ms; p < 0.01), and QTc interval (55.8 ±6.0 ms vs. 45.2 ±3.3 ms; p = 0.02) in comparison to wild type mice. The PQ prolongation was due to an infra-Hisian conduction delay (HV: 9.7 ±2.1 ms vs. 6.5 ±3.1 ms; p = 0.02). The inducibility of ventricular tachycardias during the electrophysiological studies was significantly elevated in the mutant mice (inducible animals: 88% vs. 33%; p = 0.04). Cap2gt/gt showed more abnormal distribution of connexin43 compared to WT (23.0 ±4.7% vs. 2.9 ±0.8%; p < 0.01). Myocardial fibrosis was elevated in Cap2gt/gt hearts (9.1 ±6.7% vs. 5.5 ±3.3%; p < 0.01). Conclusions Loss of CAP2 results in marked electrophysiological disturbances including impaired sinus node function, conduction delays, and susceptibility to malignant arrhythmias. Structural changes in Cap2gt/gt are associated with

  12. Arrhythmia Caused by a Drosophila Tropomyosin Mutation Is Revealed Using a Novel Optical Coherence Tomography Instrument

    PubMed Central

    Ma, Lisha; Bradu, Adrian; Podoleanu, Adrian Gh.; Bloor, James W.

    2010-01-01

    Background Dilated cardiomyopathy (DCM) is a severe cardiac condition that causes high mortality. Many genes have been confirmed to be involved in this disease. An ideal system with which to uncover disease mechanisms would be one that can measure the changes in a wide range of cardiac activities associated with mutations in specific, diversely functional cardiac genes. Such a system needs a genetically manipulable model organism that allows in vivo measurement of cardiac phenotypes and a detecting instrument capable of recording multiple phenotype parameters. Methodology and Principal Findings With a simple heart, a transparent body surface at larval stages and available genetic tools we chose Drosophila melanogaster as our model organism and developed for it a dual en-face/Doppler optical coherence tomography (OCT) instrument capable of recording multiple aspects of heart activity, including heart contraction cycle dynamics, ostia dynamics, heartbeat rate and rhythm, speed of heart wall movement and light reflectivity of cardiomyocytes in situ. We applied this OCT instrument to a model of Tropomyosin-associated DCM established in adult Drosophila. We show that DCM pre-exists in the larval stage and is accompanied by an arrhythmia previously unidentified in this model. We also detect reduced mobility and light reflectivity of cardiomyocytes in mutants. Conclusion These results demonstrate the capability of our OCT instrument to characterize in detail cardiac activity in genetic models for heart disease in Drosophila. PMID:21179409

  13. Interactive effects of social adversity and respiratory sinus arrhythmia activity on reactive and proactive aggression.

    PubMed

    Zhang, Wei; Gao, Yu

    2015-10-01

    Abnormal parasympathetic nervous system (PNS)-related cardiac activity has been linked to aggression. However, little is known about how it interacts with psychosocial adversity in predisposing to reactive-proactive aggression. In the current study, 84 male and female college students self-reported reactive and proactive aggression, and were assessed for respiratory sinus arrhythmia (RSA), a measure of PNS-related cardiac activity, during rest and when they contemplated an emotion-evoking decision-making task. Regression analyses showed that (a) resting RSA was positively linked to reactive aggression in conditions of high social adversity, and (b) RSA reactivity was positively associated with reactive but negatively associated with proactive aggression, in conditions of low social adversity. Main effects were not found for psychophysiological functioning or psychosocial adversity, suggesting the importance of their interaction. Findings support a biosocial basis for aggression and add additional support for the distinctions between reactive and proactive aggression.

  14. Prophylactic arrhythmia surgery in association with congenital heart disease.

    PubMed

    Mavroudis, Constantine; Deal, Barbara J

    2016-07-01

    Certain congenital heart anomalies make patients more susceptible to arrhythmia development throughout their lives. This poses the question whether prophylactic arrhythmia surgery should be incorporated into reparative open heart procedures for congenital heart disease. There is currently no consensus on what constitutes a standard prophylactic procedure, owing to the questions that remain regarding lesions to be performed; energy sources to use; proximity of energy source or incisions to coronary arteries, sinoatrial node, atrioventricular node; circumstances for right atrial, left atrial, or biatrial appendectomy; and whether to perform a right, left, or biatrial maze procedure. These considerations are important because prophylactic arrhythmia procedures are performed without knowing if the patient will actually develop an arrhythmia in his or her lifetime. By reviewing and summarizing the literature, congenital heart disease patients who are at risk for developing atrial arrhythmias can be identified and lesion sets can be suggested in an effort to standardize experimental protocols for prophylactic arrhythmia surgery.

  15. Prophylactic arrhythmia surgery in association with congenital heart disease

    PubMed Central

    Deal, Barbara J.

    2016-01-01

    Certain congenital heart anomalies make patients more susceptible to arrhythmia development throughout their lives. This poses the question whether prophylactic arrhythmia surgery should be incorporated into reparative open heart procedures for congenital heart disease. There is currently no consensus on what constitutes a standard prophylactic procedure, owing to the questions that remain regarding lesions to be performed; energy sources to use; proximity of energy source or incisions to coronary arteries, sinoatrial node, atrioventricular node; circumstances for right atrial, left atrial, or biatrial appendectomy; and whether to perform a right, left, or biatrial maze procedure. These considerations are important because prophylactic arrhythmia procedures are performed without knowing if the patient will actually develop an arrhythmia in his or her lifetime. By reviewing and summarizing the literature, congenital heart disease patients who are at risk for developing atrial arrhythmias can be identified and lesion sets can be suggested in an effort to standardize experimental protocols for prophylactic arrhythmia surgery. PMID:27709096

  16. Cardiac catheterization - discharge

    MedlinePlus

    Catheterization - cardiac - discharge; Heart catheterization - discharge: Catheterization - cardiac; Heart catheterization; Angina - cardiac catheterization discharge; CAD - cardiac catheterization discharge; Coronary artery disease - cardiac catheterization ...

  17. Over-expression of microRNA-1 causes arrhythmia by disturbing intracellular trafficking system

    PubMed Central

    Su, Xiaomin; Liang, Haihai; Wang, He; Chen, Guizhi; Jiang, Hua; Wu, Qiuxia; Liu, Tianyi; Liu, Qiushuang; Yu, Tong; Gu, Yunyan; Yang, Baofeng; Shan, Hongli

    2017-01-01

    Dysregulation of intracellular trafficking system plays a fundamental role in the progression of cardiovascular disease. Up-regulation of miR-1 contributes to arrhythmia, we sought to elucidate whether intracellular trafficking contributes to miR-1-driven arrhythmia. By performing microarray analyses of the transcriptome in the cardiomyocytes-specific over-expression of microRNA-1 (miR-1 Tg) mice and the WT mice, we found that these differentially expressed genes in miR-1 Tg mice were significantly enrichment with the trafficking-related biological processes, such as regulation of calcium ion transport. Also, the qRT-PCR and western blot results validated that Stx6, Braf, Ube3a, Mapk8ip3, Ap1s1, Ccz1 and Gja1, which are the trafficking-related genes, were significantly down-regulated in the miR-1 Tg mice. Moreover, we found that Stx6 was decreased in the heart of mice after myocardial infarction and in the hypoxic cardiomyocytes, and further confirmed that Stx6 is a target of miR-1. Meanwhile, knockdown of Stx6 in cardiomyocytes resulted in the impairments of PLM and L-type calcium channel, which leads to the increased resting ([Ca2+]i). On the contrary, overexpression of Stx6 attenuated the impairments of miR-1 or hypoxia on PLM and L-type calcium channel. Thus, our studies reveals that trafficking-related gene Stx6 may regulate intracellular calcium and is involved in the occurrence of cardiac arrhythmia, which provides new insights in that miR-1 participates in arrhythmia by regulating the trafficking-related genes and pathway.

  18. Venturing into ventricular arrhythmia storm: a systematic review and meta-analysis.

    PubMed

    Nayyar, Sachin; Ganesan, Anand N; Brooks, Anthony G; Sullivan, Thomas; Roberts-Thomson, Kurt C; Sanders, Prashanthan

    2013-02-01

    Ablation has substantial evidence base in the management of ventricular arrhythmia (VA). It can be a 'lifesaving' procedure in the acute setting of VA storm. Current reports on ablation in VA storm are in the form of small series and have relative small representation in a large observational series. The purpose of this study was to systematically synthesize the available literature to appreciate the efficacy and safety of ablation in the setting of VA storm. The medical electronic databases through 31 January 2012 were searched. Ventricular arrhythmia storm was defined as recurrent (≥ 3 episodes or defibrillator therapies in 24 h) or incessant (continuous >12 h) VA. Studies reporting data on VA storm patients at the individual or study level were included. A total of 471 VA storm patients from 39 publications were collated for the analysis. All VAs were successfully ablated in 72% [95% confidence interval (CI) 71-89%] and 9% (95% CI: 3-10%) had a failed procedure. Procedure-related mortality occurred in three patients (0.6%). Only 6% patients had a recurrence of VA storm. The recurrence of VA was significantly higher after ablation for arrhythmic storm of monomorphic ventricular tachycardia (VT) relative to ventricular fibrillation or polymorphic VT with underlying cardiomyopathy (odds ratio 3.76; 95% CI: 1.65-8.57; P = 0.002). During the follow-up (61 ± 37 weeks), 17% of patients died (heart failure 62%, arrhythmias 23%, and non-cardiac 15%) with 55% deaths occurring within 12 weeks of intervention. The odds of death were four times higher after a failed procedure compared with those with a successful procedure (95% CI: 2.04-8.01, P < 0.001). Ventricular arrhythmia storm ablation has high-acute success rates, with a low rate of recurrent storms. Heart failure is the dominant cause of death in the long term. Failure of the acute procedure carries a high mortality.

  19. Mutations in Calmodulin Cause Ventricular Tachycardia and Sudden Cardiac Death

    PubMed Central

    Nyegaard, Mette; Overgaard, Michael T.; Søndergaard, Mads T.; Vranas, Marta; Behr, Elijah R.; Hildebrandt, Lasse L.; Lund, Jacob; Hedley, Paula L.; Camm, A. John; Wettrell, Göran; Fosdal, Inger; Christiansen, Michael; Børglum, Anders D.

    2012-01-01

    Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a devastating inherited disorder characterized by episodic syncope and/or sudden cardiac arrest during exercise or acute emotion in individuals without structural cardiac abnormalities. Although rare, CPVT is suspected to cause a substantial part of sudden cardiac deaths in young individuals. Mutations in RYR2, encoding the cardiac sarcoplasmic calcium channel, have been identified as causative in approximately half of all dominantly inherited CPVT cases. Applying a genome-wide linkage analysis in a large Swedish family with a severe dominantly inherited form of CPVT-like arrhythmias, we mapped the disease locus to chromosome 14q31-32. Sequencing CALM1 encoding calmodulin revealed a heterozygous missense mutation (c.161A>T [p.Asn53Ile]) segregating with the disease. A second, de novo, missense mutation (c.293A>G [p.Asn97Ser]) was subsequently identified in an individual of Iraqi origin; this individual was diagnosed with CPVT from a screening of 61 arrhythmia samples with no identified RYR2 mutations. Both CALM1 substitutions demonstrated compromised calcium binding, and p.Asn97Ser displayed an aberrant interaction with the RYR2 calmodulin-binding-domain peptide at low calcium concentrations. We conclude that calmodulin mutations can cause severe cardiac arrhythmia and that the calmodulin genes are candidates for genetic screening of individual cases and families with idiopathic ventricular tachycardia and unexplained sudden cardiac death. PMID:23040497

  20. Arrhythmias in the setting of hematopoietic cell transplants.

    PubMed

    Tonorezos, E S; Stillwell, E E; Calloway, J J; Glew, T; Wessler, J D; Rebolledo, B J; Pham, A; Steingart, R M; Lazarus, H; Gale, R P; Jakubowski, A A; Schaffer, W L

    2015-09-01

    Prior studies report that 9-27% of persons receiving a hematopoietic cell transplant develop arrhythmias, but the effect on outcomes is largely unknown. We reviewed data from 1177 consecutive patients ⩾40 years old receiving a hematopoietic cell transplant at one center during 1999-2009. Transplant indication was predominately leukemia, lymphoma and multiple myeloma. Overall, 104 patients were found to have clinically significant arrhythmia: 43 before and 61 after transplant. Post-transplant arrhythmias were most frequently atrial fibrillation (N=30), atrial flutter (N=7) and supraventricular tachycardia (N=11). Subjects with an arrhythmia post transplant were more likely to have longer median hospital stays (32 days vs 23, P=<0.001), a greater probability of an intensive care unit admission (52% vs 7%; P<0.001), greater probability of in-hospital deaths (28% vs 3%, P<0.001), and greater probability of death within 1 year of transplant (41% vs 15%; P<0.001) compared with patients without arrhythmia at any time. In a multivariate model including age at transplant, diagnosis, history of pretransplant arrhythmia, and transplant-related variables, post-transplant arrhythmia was associated with a greater risk for death within a year of transplant (odds ratio 3.5, 95% confidence interval: 2.1, 5.9; P<0.001). Our data suggest that arrhythmias after transplants are associated with significant morbidity and mortality. A prospective study of arrhythmia in the transplant setting is warranted.

  1. Current treatment of ventricular arrhythmias: state of the art.

    PubMed

    Stevenson, William G

    2013-12-01

    Ventricular arrhythmias may be benign, requiring only evaluation for associated risks and then reassurance, or associated with a risk of sudden death or significant morbidity. Therapies for these arrhythmias have evolved considerably over the past 20 years. For some, a definitive, curative therapy is available in the form of catheter ablation. Others are best managed with an implantable cardioverter-defibrillator that provides effective arrhythmia termination and protection from sudden death, with antiarrhythmic drugs or ablation to control recurrent arrhythmias. Although progress has been substantial, many challenges remain.

  2. Sudden cardiac death: A reappraisal.

    PubMed

    Steinberg, Christian; Laksman, Zachary W M; Krahn, Andrew D

    2016-11-01

    Sudden cardiac death (SCD) is still among the leading causes of death in women and men, accounting for over 50% of all fatal cardiovascular events in the United States. Two arrhythmia mechanisms of SCD can be distinguished as follows: shockable rhythms (ventricular fibrillation and pulseless ventricular tachycardia) and non-shockable rhythms including asystole or pulseless electrical activity. The overall prognosis of cardiac arrest due to shockable rhythms is significantly better. While the majority of SCDs is attributed to coronary artery disease or other structural heart disease, no obvious cause can be identified in 5% of all events, and those events are labeled as sudden unexplained deaths (SUD). Those unexplained events are typically caused by rare hereditary electrical disorders or arrhythmogenic cardiomyopathies. A systematic approach to the diagnosis of cardiac arrest followed by tailored therapy based on etiology has emerged in the last 10-15 years, with significant changes of medical practice and risk management of cardiac arrest victims. The aim of this review is to summarize our contemporary understanding of SCD/SUD in adults and to discuss current concepts of management and secondary prevention in cardiac arrest victims. A full discussion of the topic of primary prevention of SCD is beyond the scope of this article.

  3. Pharmacology of cardiac potassium channels.

    PubMed

    Li, Gui-Rong; Dong, Ming-Qing

    2010-01-01

    Cardiac K(+) channels are cardiomyocyte membrane proteins that regulate K(+) ion flow across the cell membrane on the electrochemical gradient and determine the resting membrane potential and the cardiac action potential morphology and duration. Several K(+) channels have been well studied in the human heart. They include the transient outward K(+) current I(to1), the ultra-rapidly activating delayed rectifier current I(Kur), the rapidly and slowly activating delayed rectifier currents I(Kr) and I(Ks), the inward rectifier K(+) current I(K1), and ligand-gated K(+) channels, including adenosine-5'-triphosphate (ATP)-sensitive K(+) current (I(KATP)) and acetylcholine-activated current (I(KACh)). Regional differences of K(+) channel expression contribute to the variable morphologies and durations of cardiac action potentials from sinus node and atrial to ventricular myocytes, and different ventricular layers from endocardium and midmyocardium to epicardium. They also show different responses to endogenous regulators and/or pharmacological agents. K(+) channels are well-known targets for developing novel anti-arrhythmic drugs that can effectively prevent/inhibit cardiac arrhythmias. Especially, atrial-specific K(+) channel currents (I(Kur) and I(KACh)) are the targets for developing atrial-selective anti-atrial fibrillation drugs, which has been greatly progressed in recent years. This chapter concentrates on recent advances in intracellular signaling regulation and pharmacology of cardiac K(+) channels under physiological and pathophysiological conditions.

  4. Nanomaterials for Cardiac Myocyte Tissue Engineering

    PubMed Central

    Amezcua, Rodolfo; Shirolkar, Ajay; Fraze, Carolyn; Stout, David A.

    2016-01-01

    Since their synthesizing introduction to the research community, nanomaterials have infiltrated almost every corner of science and engineering. Over the last decade, one such field has begun to look at using nanomaterials for beneficial applications in tissue engineering, specifically, cardiac tissue engineering. During a myocardial infarction, part of the cardiac muscle, or myocardium, is deprived of blood. Therefore, the lack of oxygen destroys cardiomyocytes, leaving dead tissue and possibly resulting in the development of arrhythmia, ventricular remodeling, and eventual heart failure. Scarred cardiac muscle results in heart failure for millions of heart attack survivors worldwide. Modern cardiac tissue engineering research has developed nanomaterial applications to combat heart failure, preserve normal heart tissue, and grow healthy myocardium around the infarcted area. This review will discuss the recent progress of nanomaterials for cardiovascular tissue engineering applications through three main nanomaterial approaches: scaffold designs, patches, and injectable materials. PMID:28335261

  5. TRPM4 in cardiac electrical activity.

    PubMed

    Guinamard, Romain; Bouvagnet, Patrice; Hof, Thomas; Liu, Hui; Simard, Christophe; Sallé, Laurent

    2015-10-01

    TRPM4 forms a non-selective cation channel activated by internal Ca(2+). Its functional expression was demonstrated in cardiomyocytes of several mammalian species including humans, but the channel is also present in many other tissues. The recent characterization of the TRPM4 inhibitor 9-phenanthrol, and the availability of transgenic mice have helped to clarify the role of TRPM4 in cardiac electrical activity, including diastolic depolarization from the sino-atrial node cells in mouse, rat, and rabbit, as well as action potential duration in mouse cardiomyocytes. In rat and mouse, pharmacological inhibition of TRPM4 prevents cardiac ischaemia-reperfusion injuries and decreases the occurrence of arrhythmias. Several studies have identified TRPM4 mutations in patients with inherited cardiac diseases including conduction blocks and Brugada syndrome. This review identifies TRPM4 as a significant actor in cardiac electrophysiology.

  6. Cardiac Hydatid Cyst: A Case Report

    PubMed Central

    SHOJAEI, Esfandiar; YASSIN, Zeynab; REZAHOSSEINI, Omid

    2016-01-01

    Hydatid disease commonly involves liver but in rare cases, it can involve cardiac structures. A 75-yr-old farmer from Parsabad-Moghan, northwestern Iran was presented to the Emergency Room of Tehran Imam Khomeini Hospital, Tehran, Iran with dyspnea and without chest pain in 2014. A lesion compatible with hydatid cyst was found in echocardiography and confirmed by serology and MRI. Surgical treatment was done but the patient was died in recovery roo