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Implantable Cardiac Devices in the Elderly-How Risky Is It?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Despite the efficacy of implantable cardiac devices in elderly patients, a bias against their use seems to persist. A major concern about placing these devices in elderly patients is the complication rate. The incidence of complications in the elderly are not well recorded from the general population and most randomized trials excluded elderly patients. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Senthil Thambidorai, Manu Kaushik, Aimin Chen, Nazih Kadri Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

NPPA Gain-of-Function Mutation Associated with Familial Atrial FibrillationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Studies have increasingly identified genetics as an important predisposing factor for developing atrial fibrillation (AF). Mutations in NPPA, encoding the circulating hormone atrial natriuretic peptide (ANP) as well as other functional proteins, have recently been implicated in familial AF. The mechanisms underlying AF susceptibility with mutant NPPA however remain uncertain. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Robert L. Abraham, Tao Yang, Marcia Blair, Dan M. Roden, Dawood Darbar Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Cardiac Resynchronization Therapy in Patients with Recurrent Heart Failure and Intermittent LBBBEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Indications for cardiac resynchronization therapy (CRT) include prolonged QRS duration (typically LBBB), advanced heart failure (HF, NYHA III/IV), and severe left ventricular (LV) dysfunction. The role of CRT in patients with intermittent LBBB associated with acute HF is unknown. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Rehan Mahmud, Alawi A. Alsheikh-Ali, Salem Alkaabi, Arshad Rasheed Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Patients with Increasing Over Time Intracardiac Repolarization Lability Experience a Greater Increase in Their Probability of Having Ventricular TachyarrhythmiaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
It is known that elevated at baseline intracardiac repolarization lability increases the risk of life-threatening ventricular tachyarrhythmias (VT/VF) in patients with structural heart disease. We hypothesize that patients with increasing over 6 months period beat-to-beat QT variability experience a greater increase in their probability of having VT/VF than those with decreasing or stable low intracardiac repolarization lability. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Larisa Tereshchenko, Barry Fetics, Ronald Berger Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

ANP and PAI-1 Levels Predict Successful DC-Cardioversion for Persistent Atrial FibrillationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Atrial Fibrillation (AF), the most common sustained arrhythmia in clinical practice. Despite improvement in treatment, most patients suffer from symptoms and recurrences of arrhythmia. Studies on the neurohormonal remodeling in AF have become increasingly important in AF. The aim of this study was to measure plasma biomarkers in patients with AF, before and after electrical cardioversion. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Juan-Carlos Estrada, Rachel Richardson, Cindy Chen, Dawood Darbar Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

The Effect of Open - Irrigated Radiofrequency Catheter Ablation of Atrial Fibrillation on Left Atrial Pressure and B-Type Natriuretic PeptideEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Open-irrigated radiofrequency catheter ablation (oiRFA) of atrial fibrillation (AF) imposes a volume load and risk of cardiac decompensation. We sought to assess the effect of volume administration during ablation on left atrial (LA) pressure and B-type natriuretic peptide (BNP). (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Jens Seiler, Daniel Steven, Kurt C. Roberts-Thomson, Keiichi Inada, Usha B. Tedrow, Gregory F. Michaud, William G. Stevenson Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

NOS1AP Is a Genetic Modifier of Congenital Long-QT SyndromeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In the long-QT syndrome (LQTS), genetic factors other than the primary mutation may modify the probability of life-threatening events. Genome-wide association studies did show that polymorphisms in NOS1AP, a regulator of neuronal nitric oxide synthase, are associated not only with baseline QT interval but also with the risk of SCD in white adults. We tested the hypothesis that common variants in NOS1AP might modify the risk of clinical manifestations and the degree of QT interval prolongation in a South African LQTS population segregating a founder mutation in KCNQ1 (A341V), and thus having an identical arrhythmogenic subs...
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Lia Crotti, Roberto Insolia, Maria Cristina Monti, Matteo Pedrazzini, Erika Taravelli, Anna Peljto, Althea Goosen, Paul A. Brink, David A. Greenberg, Peter J. Schwartz, Alfred L. George Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Efficacy and Safety of Catheter Ablation of Ventricular Tachycardia in Elderly Patients with Coronary Heart DiseaseEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Control of recurrent ventricular tachycardia (VT) is an important determinant of quality of life in patients with implantable defibrillators. The role of invasive catheter ablation for this purpose in elderly patients with ischemic heart disease has not been defined. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Keiichi Inada, Kurt C. Roberts-Thomson, Daniel Steven, Jens Seiler, Bruce A. Koplan, Usha B. Tedrow, William G. Stevenson Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Discrepancy Between Acute and Long-Term Effects of the Calmodulin-Camkii-Calcineurin Pathway on Arrhythmogenesis in the CAVB DogEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Activation of calcium/calmodulin-dependent protein kinase II (CaMKII) has been linked to arrhythmias and heart failure. Through calcineurin, CaMKII has also been implicated in inducing electrical remodeling. Enhanced susceptibility to arrhythmias based on electrical remodeling is also present in the chronic AV block (CAVB) dog, although in the setting of physiologic hypertrophy. Because the stimuli involved (increased angiotensin II, norepinephrine, and intracellular calcium) are known CaMKII activators, this study addressed the involvement of the CaMKII-calcineurin pathway at different time points (0, 2, and 9 weeks) in t...
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Vincent J.A. Bourgonje, Marieke Schoenmakers, Jet D.M. Beekman, Roel van der Nagel, Leon J. de Windt, Toon A.B. van Veen, Marc A. Vos Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Coupling of Isolated Adult Rabbit Ventricular Myocytes to Fibroblasts Under Stress Induces AfterdepolarizationsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Ventricular fibrillation (VF) is the most lethal cardiac arrhythmia, yet the underlying mechanisms are poorly understood. VF occurs most commonly in the presence of markedly increased tissue fibrosis, as seen in aging or heart disease. We hypothesize that electrotonic coupling of ventricular myocytes to fibroblasts under stress can augment stress effects to impair myocyte repolarization reserve and promote the emergence of known VF triggers such as early afterdepolarizations (EADs) and triggered activity. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Thao P. Nguyen, James N. Weiss Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Overexpression of Dipeptidyl-Aminopeptidase-Like Protein 6 (DPP6) Alters Action Potential Characteristics through Effects on Ito1Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Through genetic studies in multiple linked families, we previously identified dipeptidyl-aminopeptidase-like protein 6 (DPP6) as a gene for idiopathic ventricular fibrillation and proposed increased expression of this gene as a likely pathogenic mechanism in this disorder. Co-expression studies in heterologous expression systems point to DPP6 as a putative β-subunit of human cardiac Kv4.3 transient outward current, but the function of DPP6 in native cardiac myocytes is unknown. Here we studied the effects of DPP6 overexpression on action potential and transient outward current characteristics in adult ventricular myocytes...
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Tamara T. Koopmann, Arie O. Verkerk, Geert J. Boink, Carol A. Remme, Maaike Buskermolen, Hanno L. Tan, Arthur A. Wilde, Connie R. Bezzina Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Epicardium-Derived Cells as Progenitors of Cardiac Fibroblasts: A Possible Role in Arrhythmogenic Right Ventricular Cardiomyopathy?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC) is an inherited disease characterized by replacement of healthy myocardium with fibrous and fatty tissue, cardiac arrhythmias, and sudden death. ARVC has been associated with mutations in desmosomal proteins, most prominently in the gene coding for plakophilin-2 (PKP2). How disruption of desmosomal proteins in cardiac myocytes leads to the disproportionate extent of fibrosis, and fat accumulation, observed in ARVC-afflicted hearts is unclear. Here, we propose that fibrofatty infiltration has its origins (at least in part) in nonmyocyte cardiac cells. Our atte...
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Stephanie Matthes, Steven Taffet, Mario Delmar Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Efficacy of Atrial Selective Strategies in Terminating Acute AF in PigsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Developing strategies that selectively target the atrium are of great clinical interest to avoid ventricular arrhythmias during treatment of atrial fibrillation (AF). Our goal was to exploit inherent differences between the atrium and the ventricle in terminating acute AF. We targeted differences in (1) ion channel makeup, i.e., the presence of an atrial-specific ion channel, the ultrarapid delayed rectifier K+ current (IKur), and (2) biophysical properties, i.e., the more negative steady-state half-inactivation membrane voltage value for the Na+ current (INa) in the atrium. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Sandeep V. Pandit, Sharon Zlochiver, Masatoshi Yamazaki, Steve R. Ennis, Sergey Mironov, Anthony J. Workman, Jerome Kalifa, Jose Jalife Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Engineering Excitable Tissues: Induction of Membrane Excitability and Impulse Conduction in Unexcitable CellsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Electrical impulses in the heart propagate via the coordinated action of membrane ion channels and gap junctions. We demonstrate for the first time an approach to convert unexcitable cells into autonomous, electrically excitable and conductive living tissue. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Robert D. Kirkton, Nenad Bursac Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Presence of Left-to-Right Atrial Inward Rectifier Potassium Current Gradient in Patients with Paroxysmal but Not Chronic Atrial FibrillationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we compared the expression and function of IK1 and IK,ACh in right atrium (RA) and LA from patients with sinus rhythm (SR), pAF, and chronic AF (cAF). (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Niels Voigt, Anne Trausch, Klaus Matschke, Ursula Ravens, Dobromir Dobrev Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Contributions of Ion Currents to Action Potential Changes and Induction of Early Afterdepolarizations and Sustained Triggered Activity During Acute Hypoxia in Ventricular MyocytesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we explored the effects of hypoxia on action potential (AP) morphology in the presence or absence of β-adrenergic stimulation. We sought to determine whether there are conditions that lead to arrhythmic disturbances in the form of greatly prolonged AP duration (APD), early afterdepolarizations (EADs) and/or triggered activity (TA). (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Namit Gaur, Will McDonald, Livia Hool, Yoram Rudy Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Inhibition of PKA Phosphorylation of RyR2 Improves Excitation-Contraction Coupling in Dystrophic CardiomyopathyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Impaired excitation-contraction coupling manifested in dystrophic cardiomyopathy is attributed to aberrant intracellular Ca2+ regulation. Increased phosphorylation of serine 2808 (S2808) of ryanodine receptors (RyR2) has been implicated in augmented sarcoplasmic reticulum (SR) Ca2+ release and cardiac dysfunction. The aim of this study was to assess whether inhibition of protein kinase A (PKA) phosphorylation of RyR2 may prevent dystrophic cardiomyopathy in mice by improving excitation-contraction coupling functions. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Na Li, Satyam Sarma, Ralph J. van Oort, Darlene Skapura, Xander H.T. Wehrens Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

ST Elevation by Sodium Channel Blockade in Structurally Discontinuous Myocardium: Excitation Failure by Current-to-Load MismatchEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Right precordial ST elevation after sodium channel blockade has been associated with right ventricular structural discontinuities and sudden cardiac death. The mechanism of ST elevation is debated. We hypothesized that sodium channel blockade causes ST elevation by current-to-load mismatch and excitation failure in structurally discontinuous myocardium. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Mark G. Hoogendijk, Mark Potse, Bas J. Boukens, Jan W. Fiolet, Jacques M.T. de Bakker, Ruben Coronel Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Central Role for Mitochondria in Regulation of Sodium CurrentEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A mutant glycerol-3-phosphate dehydrogenase 1-like A280V (A280V GPD1-L) reduces cardiac Na+ current (INa) and causes Brugada syndrome. Recent data suggest that this effect is dependent on alterations in nicotinamide adenine dinucleotide (NADH), reactive oxygen species (ROS), and protein kinase C (PKC) activation. Because NADH and PKC can activate ROS production from mitochondria, we investigated the role of this organelle in mediating the effects of mutant GPD1-L and NADH on INa. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Man Liu, Georgia Gaconnet, Barry London, Samuel C. Dudley Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Chronic Single Nephrectomy Prolongs Action Potential Duration by Inhibiting Transient Outward Currents in Left Ventricular MyocytesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Chronic kidney disease (CKD) may contribute to left ventricular hypertrophy, fibrosis, diastolic dysfunction, and impaired coronary flow reserve, which ultimately lead to an increased risk for adverse cardiovascular events. We hypothesized that cardiovascular remodeling is a continuous process starting from the early stage of CKD and sought to explore the cellular electrophysiologic changes in left ventricular myocytes after single nephrectomy (SNx) in rats. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Kuan-Cheng Chang, Shih-Sheng Chang, Hsin-Yueh Liang, An-Sheng Lee, Ming-Jai Su Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Antiarrhythmic Peptide Analogue AAP10 Prevents Cell Stress-Induced Uncoupling by Affecting Cx43 Gap Junction Channel ActivityEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Antiarrhythmic peptide (AAP) analogues are promising new antiarrhythmic drugs that target the gap junction protein connexin43 (Cx43). Their exact molecular effect is still unknown. Previous data show that one analogue prevents phosphorylation on one (serine 297 [S297]) of three new phosphorylation sites on Cx43 (S296, S297, S306) during myocardial ischemia. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Kristina Procida, Niels-Henrik Holstein-Rathlou, Thomas Hartig Braunstein, Morten Schak-Nielsen Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Mechanisms of Vascular Endothelial Growth Factor-B Up-Regulation of Cx43 in Cardiac MyocytesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In primary cultures of neonatal rat ventricular myocytes, exogenous vascular endothelial growth factor (VEGF) has been shown to rapidly increase the amount of connexin43 (Cx43), the major ventricular electrical coupling protein in gap junctions. This has led to the interesting hypothesis that VEGF, generally thought to regulate angiogenesis, may also regulate cardiac conduction by modulating expression of Cx43. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Karen O. Yee Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Ranolazine Improves Diastolic Dysfunction through Modulation of the Late Sodium CurrentEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Congestive heart failure with preserved ejection fraction (diastolic dysfunction) is an increasingly prevalent health burden and has no approved therapeutic options. We previously demonstrated that a deoxycorticosterone acetate (DOCA)-salt mouse model produces cardiac oxidative stress and diastolic dysfunction with preserved systolic function. Oxidative stress modulates inward sodium current (INa) by increasing late INa, reducing net cytosolic Ca2+ efflux, and impairing myocyte relaxation. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Joshua D. Lovelock, Harvey A. Lardin, Hong Liu, Praveen Kumar, Narayan Pokhrel, Dewan Zeng, Luiz Belardinelli, Samuel C. Dudley Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Electrogram Fractionation due to Subepicardial Fibrosis is Undetectable on Endocardial MappingEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The right ventricular subepicardium is the primary location of fibrofatty replacement in arrhythmogenic right ventricular cardiomyopathy and is thought to be the source of right precordial ST-segment elevation in Brugada syndrome. Although structural heart disease is an exclusion criterion for Brugada syndrome, clinically undetectable structural abnormalities have been suggested to play a role in a subset of Brugada patients. Fractionation of local electrograms is then expected but has only rarely been observed in endocardial mapping studies of Brugada patients. We hypothesized that structural changes limited to subepicard...
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Jacques M.T. de Bakker, Mark G. Hoogendijk, André C. Linnenbank, Ruben Coronel, Alain Vinet, Mark Potse Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

TBX3 Overexpression Reprograms Neonatal Cardiac Myocytes Toward Pacemaker CellsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we investigated the phenotype of lentivirally delivered TBX3 in myocytes and the usefulness of TBX3 gene transfer in biopacemaker engineering. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Gerard J.J. Boink, Martijn L. Bakker, Arie O. Verkerk, Diane Bakker, Shirley C.M. van Amersfoorth, Jurgen Seppen, Jacques M.T. de Bakker, Vincent M. Christoffels, Hanno L. Tan Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Image-Based Estimation of Myocardial Fiber Orientations for Patient-Specific Models of Cardiac ElectrophysiologyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study aimed to develop a pipeline that uses in vivo patient images to estimate fiber orientations for heart simulations. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Fijoy Vadakkumpadan, Hermenegild Arevalo, Can Ceritoglu, Michael Miller, Natalia Trayanova Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Complex Interactions Between Sinoatrial Node and Atrium During Atrial ArrhythmiasEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Both canine and human sinoatrial nodes (SANs) are functionally connected to the surrounding atrium by several discrete sinoatrial exit pathways (SEPs). These SEPs not only are important in maintaining pacemaking function but also participate in atrial reentrant arrhythmias such as atrial flutter (AFl) and atrial fibrillation (AF). (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Vadim V. Fedorov, Alexey V. Glukhov, Roger Chang, Geran Kostecki, Deborah L. Janks, Nader Moazami, Richard B. Schuessler, Igor R. Efimov Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Diminished Contractile Reserve in Ventricle from Hypoplastic Left Heart Syndrome is not Due to Reduced Response of Calcium CurrentEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
As pediatric cardiac surgery is increasingly performed in the first year of life, the need for understanding calcium regulation in this age group is becoming more important. Thus, we examined the effect of sympathetic stimulation on contractility and calcium current (ICa) in ventricular biopsies from hypoplastic left heart syndrome (HLHS, age (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Guoliang Ding, Rob F. Wiegerinck, Carlo M. Zeidenweber, Ming Shen, Kirk R. Kanter, Paul M. Kirshbom, Brian E. Kogon, Ronald W. Joyner, Mary B. Wagner Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Electromechanical Delay is Heterogeneous in the Failing Canine Ventricles Both during Left Bundle Branch Block and Following Biventricular PacingEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The three-dimensional (3-D) distribution of electromechanical delay (EMD), the time interval between onset of myofiber shortening and that of electrical activation, has not been characterized in the failing heart. The aim of this study was to quantify this EMD distribution during left bundle branch block (LBBB) and biventricular pacing (BiV). We hypothesized that heterogeneity in EMD distribution arises from myofiber prestretch in the different regions of the failing heart and depends on the electrical activation sequence. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Jason L. Constantino, Viatcheslav Gurev, Natalia A. Trayanova Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Multiple Low-Energy Shock Therapy Terminates Atrial Flutter and Fibrillation More Effectively than ATPEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Implantable cardioverter-defibrillator (ICD) therapy for atrial fibrillation (AF) and flutter (AFl) currently is limited by pain induced by defibrillation shocks. Antitachycardia pacing (ATP) is a painless therapy but is not 100% effective in terminating AF/AFl. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Christina M. Ambrosi, Crystal M. Ripplinger, Igor R. Efimov, Vadim V. Fedorov Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Intrinsic Cardiac Nerve Activities and Spontaneous Onset of Atrial TachyarrhythmiaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Intrinsic cardiac ganglionated plexuses are known to play important roles in cardiac arrhythmogenesis. We sought to directly record intrinsic cardiac nerve activity (ICNA) and extrinsic cardiac nerve activity (ECNA) simultaneously and to test the hypothesis that ICNA always precedes the onset of spontaneous atrial tachyarrhythmia. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Eue-Keun Choi, Seong-Wook Han, Dae-Hyeok Kim, Samuel Hwang, Sameh Sayfo, Mark J. Shen, Gianfranco Piccirillo, Chun Hwang, Shien-Fong Lin, Peng-Sheng Chen Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Genetic Background Determines Magnitude of Late Sodium Current, Extent of Intracellular Na+ and Ca2+ Dysregulation, and Severity of Cardiomyopathy in Murine Sodium ChannelopathyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Mutations in SCN5A may be associated with the development of myocardial structural abnormalities with increasing age, likely caused by intracellular sodium ([Na+]i) and calcium ([Ca2+]i) dysregulation secondary to increased sodium influx due to enhanced late sodium current (INa,late). We previously showed that Scn5a-1798insD+/- transgenic mice of two distinct inbred strains display variable conduction disease severity. Here, we hypothesized that genetic background determines magnitude of INa,late, extent of [Na+]i and [Ca2+]i dysregulation, and severity of cardiomyopathy in this mouse model. (Source: Heart Rhythm)
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Carol Ann Remme, Antonius Baartscheer, Arie O. Verkerk, Markus A. Engelen, Arthur A.M. Wilde, Harold V. van Rijen, Jacques M.T. de Bakker, Connie R. Bezzina Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Reduction in Cardiac Kir3.4 Channel Expression Causes Congenital Long QT Syndrome: A Functional Role of Girk Currents in Ventricular RepolarizationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Ventricular repolarization is promoted by delayed rectifier potassium currents. Mutations in the genes underlying these currents, primarily IKr, IKs, and IK1, have been found to cause congenital long QT syndrome (LQTS), which is an inherited disorder leading to sudden cardiac death from fatal cardiac arrhythmias. Kir3.1/3.4 channels have been ascribed a prominent role in atrial and nodal parasympathetic regulation, where acetylcholine-mediated muscarinic stimulation leads to activation of this channel complex, thereby generating G-protein-coupled inward rectifier potassium channel current (IK,ACh). However, a functional ro...
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Bo Liang, Yanzong Yang, Yiqing Yang, Jinqiu Liu, Morten Grunnet, Søren-Peter Olesen, Yi-Han Chen, Thomas Jespersen Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

Rate-Dependent Action Potential Alternans in Human Heart Failure Implicate Abnormalities in Intracellular Calcium HandlingEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cellular, tissue, and clinical studies link action potential (AP) alternans to ventricular tachycardia (VT) and fibrillation (VF). We recently that alternans in AP voltage (APV-ALT) can predict VT/VF in patients with heart failure (HF) and that APV-ALT implicate reduced calcium uptake (Iup) into the sarcoplasmic reticulum. However, the rate-dependent mechanisms for APV-ALT in failing versus nonfailing human myocardium are poorly understood. Using a combined clinical and modeling approach, we sought to test the hypothesis that reduced Iup leads to unique rate-dependent APV-ALT that distinguish patients en route to VT/VF fro...
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Jason D. Bayer, Sanjiv M. Narayan, Gautam G. Lalani, Natalia A. Trayanova Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

AZD1305 has Atrial-Predominant Electrophysiologic Actions and is Effective in Suppressing Atrial Fibrillation in the DogEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We examined the electrophysiologic effects of the combined ion channel blocker AZD1305 in the right atrium (RA) and ventricle in anesthetized dogs in vivo (n = 8) and in the dog arterially perfused RA and left ventricular wedge preparation in vitro (n = 5-9). Action potentials (APs) and a pseudo-ECG were recorded in vitro and monophasic AP and surface ECG in vivo. AZD1305 did not change heart rate or blood pressure in vivo but prolonged AP duration (APD90) and increased effective refractory period (ERP) and diastolic threshold of excitation (DTE) predominantly in atria both in vitro and in vivo. Furthermore, in vitro AZD13...
Source: Heart Rhythm - November 1, 2009 Category: Cardiology Authors: Alexander Burashnikov, Jose M. Di Diego, Gunilla Linhardt, Leif Carlsson, Charles Antzelevitch Tags: Cardiac Electrophysiology Society Abstracts Source Type: journals

ErratumEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In the article titled, “National ICD Registry Annual Report 2008: Review of the ICD Registry's Third Year, Expansion to include Lead Data and Pediatric ICD Procedures, and Role for Measuring Performance,” which appears in the September 2009 edition of the Journal (2009;6:1397-1401), the name of Charles Berul, MD was inadvertently omitted. (Source: Heart Rhythm)
Source: Heart Rhythm - October 13, 2009 Category: Cardiology Tags: Errata Source Type: journals

ErratumEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In the article titled “Free radical scavenger specifically prevents ischemic focal ventricular tachycardia” by Dezhi Xing, MD, Ashok K. Chaudhary, PhD, Francis J. Miller, Jr., MD, James B. Martins, MD, that published in the April 2009 issue of the Journal (Heart Rhythm 2009;6:530-6), was incorrect. (Source: Heart Rhythm)
Source: Heart Rhythm - October 5, 2009 Category: Cardiology Tags: Errata Source Type: journals

ClinicalEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Moss and colleagues (N Engl J Med 2009 Sep 1; Epub, PMID 19723701) evaluated whether cardiac resynchronization therapy (CRT) reduces mortality and heart failure in patients with mild cardiac symptoms, reduced ejection fraction (EF), and wide QRS complex. Over 4.5 years, 1,820 patients with ischemic or nonischemic cardiomyopathy, EF ≤0.30, QRS ≥130 ms, and New York Heart Association class I or II symptoms were randomized in a 3:2 ratio to CRT with defibrillator (1,089 patients) or an implanted defibrillator (731 patients). The primary end-point was all-cause mortality or heart failure event, whichever occurred first. Du...
Source: Heart Rhythm - September 24, 2009 Category: Cardiology Authors: N.A. Mark Estes Tags: EP News--Associate Editors: Peng-Sheng Chen and Mark Estes III Source Type: journals

Basic and TranslationalEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Lalani et al (J Med Genet 2009;46:168, PMID 18812404) studied the relationship between bone morphogenetic protein (BMP) and Wolff-Parkinson-White syndrome (WPW). BMP is important in the development of annulus fibrosus in mice. The authors identified five individuals with nonrecurrent deletions of 20p12.3. Four of these individuals had WPW syndrome with variable dysmorphisms and neurocognitive delay. With the exception of one maternally inherited deletion, all occurred de novo, and the smallest of these harbored a single gene, BMP2. In two individuals with additional features of Alagille syndrome, deletion of both JAG1 and ...
Source: Heart Rhythm - September 24, 2009 Category: Cardiology Authors: Peng-Sheng Chen Tags: EP News--Associate Editors: Peng-Sheng Chen and Mark Estes III Source Type: journals

Actively rethinking the reentrant circuitEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Common atrial flutter (AFL), a macrorentrant circuit involving the right atrium (RA), is characterized by its dependence on the cavotricuspid isthmus (CTI), the latter demonstrated by concealed entrainment and successful termination of AFL during its ablation. Most components of the AFL reentrant circuit have been well described. Using various forms of activation sequence mapping, including the techniques of entrainment mapping and postpacing intervals (PPIs), the anterior and the posterior boundaries of AFL have been well defined. From these prior observations, it has been considered that the tricuspid annulus serves as t...
Source: Heart Rhythm - September 16, 2009 Category: Cardiology Authors: Jayakumar Sahadevan, Albert L. Waldo Tags: Editorial Commentary Source Type: journals

To the EditorEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We wish to thank Dr. Thomas for his interest and recognition that our recently published article on arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) filled a need to provide a comprehensive profile on patients newly diagnosed with this disease. Dr. Thomas expressed puzzlement by the omission of data regarding the right ventricular outflow tract (RVOT) in our cohort. From a historic point of view, in 1992, Ricci et al. reported that the maximal diameter of the RVOT by magnetic resonance imaging (MRI) in 15 patients with ARVC/D was 34 ± 6 mm compared with 21 ± 7 mm in patients with dilated cardiomyopathy ...
Source: Heart Rhythm - September 7, 2009 Category: Cardiology Authors: Frank Marcus, Duane Sherrill, Kathleen Gear, Harikrishna Tandri Tags: Letters to the Editor Source Type: journals

To the EditorEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Marcus et al are to be congratulated for filling in a gap in our knowledge of arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). Until now, the clinical features and results of diagnostic tests were known for patients with overt manifestations who often fulfilled the task force criteria. A similar strategy has been applied to describe familial disease among individuals who may or may not eventually be diagnosed with ARVC/D based on either task force criteria or modified task force criteria adapted to describe familial disease. What has been missing are data on newly diagnosed disease, a particularly vexing...
Source: Heart Rhythm - September 7, 2009 Category: Cardiology Authors: Boban Thomas, Ruben Ramos, Nuno Jalles Tavares Tags: Letters to the Editor Source Type: journals

Frequency-domain versus time-domain analysis: Optimizing complex fractionated atrial electrogram identification for atrial fibrillation ablationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Since the landmark paper of Michel Haïssaguerre and colleagues, ablation methods have been applied increasingly in the treatment of atrial fibrillation (AF). A variety of procedures have been developed, none of which are uniformly effective, and improving their therapeutic efficacy is a significant challenge in clinical electrophysiology. (Source: Heart Rhythm)
Source: Heart Rhythm - September 2, 2009 Category: Cardiology Authors: Stanley Nattel Tags: Basic/Clinical Implications--Associate Editor: Stanley Nattel Source Type: journals

Myocyte-fibroblast interactions—Risky connectionsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The role of fibroblasts in the induction of conductance disturbances and arrhythmia has received an increasing amount of attention in recent years. Research into the interactions between fibroblasts and myocytes shows that conduction velocity (CV) can be both accelerated and slowed depending on the density, coupling, and electrical properties of the fibroblasts. In the present issue of Heart Rhythm, Xie et al unravel further complexities in the consequences of mixing fibroblasts and myocytes using computer modeling. The study explores not only the effect of density and degree of coupling of fibroblasts but also the effect ...
Source: Heart Rhythm - August 25, 2009 Category: Cardiology Authors: Morten Schak Nielsen Tags: Editorial Commentary Source Type: journals

Connexin, connection, conductance: Towards understanding induction of arrhythmias?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Myocardial ischemia can result in three different forms of injury to the heart: arrhythmia, contractile dysfunction, and myocardial infarction. Arrhythmia and contractile dysfunction are reversible conditions that appear early (within few minutes) when ischemia occurs in a beating heart. (Source: Heart Rhythm)
Source: Heart Rhythm - August 25, 2009 Category: Cardiology Authors: R. Sundset, K. Ytrehus, S.-O. Mikalsen Tags: Editorial Commentary Source Type: journals

CCEP fellowship training requirements: Flexibility should be an advantageEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this issue of Heart Rhythm, Chugh et al report the results of a survey of clinical cardiac electrophysiology (CCEP) fellowship program directors and make several proposals for changes in the structure of CCEP fellowships. This thoughtful article raises several important questions related to the content and duration of CCEP fellowships and should be of interest to electrophysiologists in both academic and practice settings. (Source: Heart Rhythm)
Source: Heart Rhythm - August 25, 2009 Category: Cardiology Authors: Bruce D. Lindsay, John P. DiMarco Tags: Editorial Commentary Source Type: journals

Training in clinical cardiac electrophysiology at the crossroadsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The content of training programs in clinical cardiac electrophysiology (CCEP) is based on the convergence of three forces: (1) the historical underpinnings of the basic and clinical sciences of cardiac electrophysiology (EP), (2) the rapid accumulation of new clinical knowledge and dramatic evolution of clinically oriented technologies, and (3) the construction of formal training programs in CCEP. Recognizing possible problems in CCEP training programs, a working group from among the program directors surveyed their colleagues, and a report and analysis of the responses is presented in this issue of Heart Rhythm. The repor...
Source: Heart Rhythm - August 25, 2009 Category: Cardiology Authors: Robert J. Myerburg Tags: Editorial Commentary Source Type: journals

Complications from implantable cardioverter defibrillator implantation: Do the risks outweigh the benefits?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Utilization of implantable cardioverter defibrillators (ICDs) has exploded in the last decade because of the implantation of these devices for primary prophylactic indications. The life-saving benefit of ICDs for both primary and secondary indications has been well demonstrated, with a >30% relative risk reduction in mortality in the case of primary prophylactic indications and a 50% RRR in secondary indications. These data are derived from clinical trials that provide invaluable data on the effects of such therapy, yet these trials include highly selected populations, the outcomes of which may not accurately reflect eithe...
Source: Heart Rhythm - August 25, 2009 Category: Cardiology Authors: Ratika Parkash Tags: Editorial Commentary Source Type: journals

Treatment of PVCs post-myocardial infarction: Will we get fooled again?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In the 1980s, electrophysiologists learned an important lesson about premature ventricular complexes (PVCs) in post-myocardial infarction (post-MI) patients. PVCs were associated with an increased risk for death, so it seemed reasonable that drug suppression of PVCs would decrease the risk. Not so. Drug suppression of PVCs could be dangerous even if left ventricular ejection fraction (EF) improved. Attempts at PVC suppression were abandoned only to resurface now as methods for quantitation of myocardial scarring and ablation of PVCs have advanced sufficiently. (Source: Heart Rhythm)
Source: Heart Rhythm - August 25, 2009 Category: Cardiology Authors: Renee M. Sullivan, Brian Olshansky Tags: Editorial Commentary Source Type: journals

The antiarrhythmic blow to the sternum: ThumpversionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
It has long been known that a blow to the chest can restore a heartbeat in patients with Adams-Stokes syncope. A chest thump can also terminate ventricular tachycardia (VT) or ventricular fibrillation (VF). Although counterintuitive, this simple maneuver has proved life saving. Few know when this maneuver was introduced, how its effectiveness was discovered, and what, if any, are its clinical possibilities. Like much in clinical medicine, the introduction of chest thumping resulted from an unplanned and serendipitous observation. (Source: Heart Rhythm)
Source: Heart Rhythm - August 24, 2009 Category: Cardiology Authors: Bernard Lown Tags: Historical Review Source Type: journals