552 results match your criteria Electrical Alternans


Demonstrating the mechanism of electrical alternans in cardiac tamponade: "the swinging heart".

Med J Aust 2020 Jun 29. Epub 2020 Jun 29.

Government Medical College and Hospital, Chandigarh, India.

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http://dx.doi.org/10.5694/mja2.50687DOI Listing

Incessant accelerated idioventricular rhythm mimicking preexcitation.

J Electrocardiol 2020 Jun 11;61:137-140. Epub 2020 Jun 11.

Arrhythmia Unit, Cardiology Department, Hospital La Luz - Quironsalud, Madrid, Spain.

ECG of patients with Wolf Parkinson White (WPW) syndrome may simulate other entities such as myocardial infarction, ventricular premature complexes, ventricular bigeminy, accelerated idioventricular rhythm, intermittent bundle branch block or electrical alternans. On the other hand, the opposite can also occur where these other conditions may simulate WPW. We present the case of a young patient referred for WPW ablation showing an incessant accelerated idioventricular rhythm mimicking preexcitation. Read More

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http://dx.doi.org/10.1016/j.jelectrocard.2020.06.015DOI Listing

Simulation of the Effects of Extracellular Calcium Changes Leads to a Novel Computational Model of Human Ventricular Action Potential With a Revised Calcium Handling.

Front Physiol 2020 15;11:314. Epub 2020 Apr 15.

Computational Physiopathology Unit, Department of Electrical, Electronic and Information Engineering "Guglielmo Marconi", University of Bologna, Cesena, Italy.

The importance of electrolyte concentrations for cardiac function is well established. Electrolyte variations can lead to arrhythmias onset, due to their important role in the action potential (AP) genesis and in maintaining cell homeostasis. However, most of the human AP computer models available in literature were developed with constant electrolyte concentrations, and fail to simulate physiological changes induced by electrolyte variations. Read More

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http://dx.doi.org/10.3389/fphys.2020.00314DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7174690PMC

Knockout of MD1 contributes to sympathetic hyperactivity and exacerbates ventricular arrhythmias following heart failure with preserved ejection fraction via NLRP3 inflammasome activation.

Exp Physiol 2020 Jun 6;105(6):966-978. Epub 2020 May 6.

Department of Cardiology, Renmin Hospital of Wuhan University, Wuchang, Wuhan, China.

New Findings: What is the central question of this study? In this study, we investigated whether MD1 interacted with the sympathetic nerves in ventricular arrhythmia (VA) during heart failure with preserved ejection fraction (HFpEF). What is the main finding and its importance? Mice with HFpEF showed increased susceptibility to VA, adverse electrical remodelling, impaired heart rate variability, enhanced sympathetic hyperactivity, activation of the NLRP3 inflammasome and increased interleukin-1β release. These changes induced by HFpEF were exacerbated by MD1 deficiency. Read More

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http://dx.doi.org/10.1113/EP088390DOI Listing

The Epileptic Heart: Concept and clinical evidence.

Epilepsy Behav 2020 Apr 25;105:106946. Epub 2020 Feb 25.

Harvard Medical School, Beth Israel Deaconess Medical Center, Division of Cardiovascular Medicine and Department of Neurology, Boston, MA United States of America.

Sudden unexpected death in epilepsy (SUDEP) is generally considered to result from a seizure, typically convulsive and usually but not always occurring during sleep, followed by a sequence of events in the postictal period starting with respiratory distress and progressing to eventual cardiac asystole and death. Yet, recent community-based studies indicate a 3-fold greater incidence of sudden cardiac death in patients with chronic epilepsy than in the general population, and that in 66% of cases, the cardiac arrest occurred during routine daily activity and without a temporal relationship with a typical seizure. To distinguish a primarily cardiac cause of death in patients with epilepsy from the above description of SUDEP, we propose the concept of the "Epileptic Heart" as "a heart and coronary vasculature damaged by chronic epilepsy as a result of repeated surges in catecholamines and hypoxemia leading to electrical and mechanical dysfunction. Read More

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http://dx.doi.org/10.1016/j.yebeh.2020.106946DOI Listing

[T-wave alternans and atrial tachycardia].

Orv Hetil 2020 Feb;161(7):275-277

Kardiológiai Osztály, Budai Irgalmasrendi Kórház Budapest, Árpád fejedelem útja 7., 1027.

A 70-year-old male patient presented with acute respiratory failure. ECG at admission showed atrial tachycardia with macro T-wave alternans that disappeared as soon as normal sinus rhythm had returned. This ECG shape was not accompanied by either QT-prolongation or acute ischaemia. Read More

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http://dx.doi.org/10.1556/650.2019.31644DOI Listing
February 2020

Pressure-impedance analysis: Assist the diagnosis and classification of ineffective esophageal motility disorder.

J Gastroenterol Hepatol 2020 Jan 12. Epub 2020 Jan 12.

Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.

Background And Aim: We elucidated the clinical significance of distal contractile integral-to-esophageal impedance integral (EII) ratio (DCIIR) in ineffective esophageal motility (IEM) adult patients.

Methods: We recruited 101 patients with IEM (48.38 ± 1. Read More

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http://dx.doi.org/10.1111/jgh.14981DOI Listing
January 2020

Delay differential equation-based models of cardiac tissue: Efficient implementation and effects on spiral-wave dynamics.

Chaos 2019 Dec;29(12):123128

School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.

Delay differential equations (DDEs) recently have been used in models of cardiac electrophysiology, particularly in studies focusing on electrical alternans, instabilities, and chaos. A number of processes within cardiac cells involve delays, and DDEs can potentially represent mechanisms that result in complex dynamics both at the cellular level and at the tissue level, including cardiac arrhythmias. However, DDE-based formulations introduce new computational challenges due to the need for storing and retrieving past values of variables at each spatial location. Read More

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http://dx.doi.org/10.1063/1.5128240DOI Listing
December 2019

Examining Cardiomyocyte Dysfunction Using Acute Chemical Induction of an Ageing Phenotype.

Int J Mol Sci 2019 Dec 27;21(1). Epub 2019 Dec 27.

School of Life, Health and Chemical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK.

Much effort is focussed on understanding the structural and functional changes in the heart that underlie age-dependent deterioration of cardiac performance. Longitudinal studies, using aged animals, have pinpointed changes occurring to the contractile myocytes within the heart. However, whilst longitudinal studies are important, other experimental approaches are being advanced that can recapitulate the phenotypic changes seen during ageing. Read More

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http://dx.doi.org/10.3390/ijms21010197DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6982016PMC
December 2019

Clinical significance of 12 lead ECG changes in patients undergoing pericardiocentesis for cardiac tamponade.

Acta Cardiol 2019 Dec 27:1-4. Epub 2019 Dec 27.

Division of Cardiology, Thomas Jefferson University Hospital, Philadelphia, PA, USA.

The electrocardiogram (ECG) is one of the initial tests done in patients suspected of having a cardiac Tamponade. Historically the emphasis has been on low QRS voltage and electrical alternans, which lacks specificity and sensitivity respectively. Majority of these studies included patients with pericardial effusions without tamponade. Read More

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http://dx.doi.org/10.1080/00015385.2019.1700336DOI Listing
December 2019

Lights, camera, path splitter: a new approach for truly simultaneous dual optical mapping of the heart with a single camera.

BMC Biomed Eng 2019 27;1. Epub 2019 Sep 27.

Sheikh Zayed Institute for Pediatric and Surgical Innovation: Children's National Health System, 6th floor, M7708, 111 Michigan Avenue NW, Washington, DC 20010, USA.

Background: Optical mapping of transmembrane voltage and intracellular calcium is a powerful tool for investigating cardiac physiology and pathophysiology. However, simultaneous dual mapping of two fluorescent probes remains technically challenging. We introduce a novel, easy-to-use approach that requires a path splitter, single camera and excitation light to simultaneously acquire voltage and calcium signals from whole heart preparations, which can be applied to other physiological models - including neurons and isolated cardiomyocytes. Read More

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http://dx.doi.org/10.1186/s42490-019-0024-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6876868PMC
September 2019

Microvolt T-wave alternans at the end of surgery is associated with postoperative mortality in cardiac surgery patients.

Sci Rep 2019 11 22;9(1):17351. Epub 2019 Nov 22.

Department of Anaesthesiology and Pain medicine, Seoul National University College of Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea.

Microvolt T-wave alternans (MTWA), which reflects electrical dispersion of repolarization, is known to be associated with arrhythmia or sudden cardiac death in high risk patients. In this study we investigated the relationship between MTWA and postoperative mortality in 330 cardiac surgery patients. Electrocardiogram, official national data and electric chart were analysed to provide in-hospital and mid-term outcome. Read More

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http://dx.doi.org/10.1038/s41598-019-53760-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6874567PMC
November 2019

Images of the month 2: Electrocardiographic QRS alternans caused by gastric volvulus.

Clin Med (Lond) 2019 Nov;19(6):528-529

South West Acute Hospital, Enniskillen, UK and School of Medicine, Dentistry, and Biomedical Sciences, Belfast, UK

QRS electrical alternans is characterised by alternating amplitude of the QRS complexes, and is well-documented in cardiac conditions such as pericardial effusion. We describe a case of QRS alternans in a patient with gastric volvulus. Read More

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http://dx.doi.org/10.7861/clinmed.2019-0259DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6899249PMC
November 2019

Assessment of ventricular repolarization instability in terms of T-wave alternans induced by head-down bed-rest immobilization.

Physiol Meas 2019 10 30;40(10):104001. Epub 2019 Oct 30.

Department of Biomedical Engineering, Lund University, Lund, Sweden. BSICoS Group, Instituto de Investigación en Ingeniería de Aragón (I3A), IIS Aragón, Universidad de Zaragoza, Zaragoza, Spain.

Objective: To assess the effects of different durations of simulated microgravity exposure on ventricular repolarization (VR) in terms of T-wave alternans (TWA) as well as to test whether an increase in VR heterogeneity could be detected once normal gravity was restored.

Approach: A total of 63 healthy volunteers were recruited in several head-down bed-rest (HDBR) experiments in the context of the European Space Agency bed-rest strategy. TWA is evaluated during the night period using ambulatory ECG recordings, before, during and after long- (60 d), mid- (21 d) and short- (5 d) duration HDBR by the long-term averaging technique. Read More

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http://dx.doi.org/10.1088/1361-6579/ab4c18DOI Listing
October 2019
2 Reads

Restitution and Stability of Human Ventricular Action Potential at High and Variable Pacing Rate.

Biophys J 2019 12 26;117(12):2382-2395. Epub 2019 Aug 26.

University of Parma, Department of Chemistry, Life Sciences and Environmental Sustainability, Parma, Italy. Electronic address:

Despite the key role of beat-to-beat action potential (AP) variability in the onset of ventricular arrhythmias at high pacing rate, the knowledge of the involved dynamics and of effective prognostic parameters is largely incomplete. Electrical restitution (ER), the way AP duration (APD) senses changes in preceding cycle length (CL), has been used to monitor transition to arrhythmias. The use of standard ER (sER), though, is controversial, not always suitable for in vivo and only rarely for clinical applications. Read More

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http://dx.doi.org/10.1016/j.bpj.2019.08.020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6990376PMC
December 2019
2 Reads

Cardiac electrical instability in newly diagnosed/chronic epilepsy tracked by Holter and ECG patch.

Neurology 2019 09;93(10):450-458

From Beth Israel Deaconess Medical Center (T.D.P., B.D.N., K.B.K., S.C.S., R.L.V.), Harvard Medical School, Boston, MA; and LivaNova PLC (B.O.), London, UK.

Objective: We hypothesized that cardiac electrical instability and abnormal autonomic tone result from cumulative cardiac injury sustained in recurrent seizures. We tested this hypothesis by comparing T-wave alternans (TWA) and heart rate variability (HRV), both established markers of sudden cardiac death (SCD) risk, in patients with chronic as compared to newly diagnosed epilepsy.

Methods: In this prospective, observational cohort study, patients (newly diagnosed epilepsy, n = 6, age 41. Read More

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http://dx.doi.org/10.1212/WNL.0000000000008077DOI Listing
September 2019
4 Reads

Understanding AF Mechanisms Through Computational Modelling and Simulations.

Arrhythm Electrophysiol Rev 2019 Jul;8(3):210-219

Department of Biomedical Engineering and the Institute for Computational Medicine, Johns Hopkins University Baltimore, MD, US.

AF is a progressive disease of the atria, involving complex mechanisms related to its initiation, maintenance and progression. Computational modelling provides a framework for integration of experimental and clinical findings, and has emerged as an essential part of mechanistic research in AF. The authors summarise recent advancements in development of multi-scale AF models and focus on the mechanistic links between alternations in atrial structure and electrophysiology with AF. Read More

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http://dx.doi.org/10.15420/aer.2019.28.2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6702471PMC
July 2019
2 Reads

A Protocol for Transverse Cardiac Slicing and Optical Mapping in Murine Heart.

Front Physiol 2019 25;10:755. Epub 2019 Jun 25.

Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China.

Thin living tissue slices have recently emerged as a new tissue model for cardiac electrophysiological research. Slices can be produced from human cardiac tissue, in addition to small and large mammalian hearts, representing a powerful model system for preclinical and translational heart research. In the present protocol, we describe a detailed mouse heart transverse slicing and optical imaging methodology. Read More

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http://dx.doi.org/10.3389/fphys.2019.00755DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6603341PMC
June 2019
4 Reads

Effects of mechano-electrical feedback on the onset of alternans: A computational study.

Chaos 2019 Jun;29(6):063126

Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada.

Cardiac alternans is a heart rhythm instability that is associated with cardiac arrhythmias and may lead to sudden cardiac death. The onset of this instability, which is linked to period-doubling bifurcation and may be a route to chaos, is of particular interest. Mechano-electric feedback depicts the effects of tissue deformation on cardiac excitation. Read More

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http://dx.doi.org/10.1063/1.5095778DOI Listing
June 2019
4 Reads

Prediction of the mechanical response of cardiac alternans by using an electromechanical model of human ventricular myocytes.

Biomed Eng Online 2019 Jun 7;18(1):72. Epub 2019 Jun 7.

Department of IT Convergence Engineering, Kumoh National Institute of Technology, 61 Daehak-ro, Gumi, Gyeongbuk, 39177, Republic of Korea.

Purpose: Although the quantitative analysis of electromechanical alternans is important, previous studies have focused on electrical alternans, and there is a lack quantitative analysis of mechanical alternans at the subcellular level according to various basic cycle lengths (BCLs). Therefore, we used the excitation-contraction (E-C) coupling model of human ventricular cells to quantitatively analyze the mechanical alternans of ventricular cells according to various BCLs.

Methods: To implement E-C coupling, we used calcium transient data, which is the output data of electrical simulation using the electrophysiological model of human ventricular myocytes, as the input data of mechanical simulation using the contractile myofilament dynamics model. Read More

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http://dx.doi.org/10.1186/s12938-019-0690-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6555982PMC
June 2019
8 Reads

Dynamic clamping human and rabbit atrial calcium current: narrowing I window abolishes early afterdepolarizations.

J Physiol 2019 07 12;597(14):3619-3638. Epub 2019 Jun 12.

Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow, UK.

Key Points: Early-afterdepolarizations (EADs) are abnormal action potential oscillations and a known cause of cardiac arrhythmias. Ventricular EADs involve reactivation of a Ca current (I ) in its 'window region' voltage range. However, electrical mechanisms of atrial EADs, a potential cause of atrial fibrillation, are poorly understood. Read More

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http://dx.doi.org/10.1113/JP277827DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6767690PMC
July 2019
11 Reads

Body surface distribution of T wave alternans is modulated by heart rate and ventricular activation sequence in patients with cardiomyopathy.

PLoS One 2019 10;14(4):e0214729. Epub 2019 Apr 10.

Division of Cardiology, University Health Network, Toronto, Canada.

Background: T wave alternans (TWA) is an electrocardiographic marker of heightened sudden death risk from ventricular tachyarrhythmias in patients with cardiomyopathy. TWA is evaluated from the 12-lead electrocardiogram, Frank lead, or Holter lead recordings, however these clinical lead configurations will not record TWA from adjacent regions of the body torso.

Objective: We tested the hypothesis that changing heart rate or ventricular activation may alter the body surface distribution of TWA such that the clinical ECG leads fail to detect TWA in some patients; thereby producing a false-negative test. Read More

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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0214729PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6457562PMC
December 2019
23 Reads

Isostable reduction of oscillators with piecewise smooth dynamics and complex Floquet multipliers.

Authors:
Dan Wilson

Phys Rev E 2019 Feb;99(2-1):022210

Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville, Tennessee 37996, USA.

Phase-amplitude reduction is a widely applied technique in the study of limit cycle oscillators with the ability to represent a complicated and high-dimensional dynamical system in a more analytically tractable set of coordinates. Recent work has focused on the use of isostable coordinates, which characterize the transient decay of solutions toward a periodic orbit, and can ultimately be used to increase the accuracy of these reduced models. The breadth of systems to which this phase-amplitude reduction strategy can be applied, however, is still rather limited. Read More

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http://dx.doi.org/10.1103/PhysRevE.99.022210DOI Listing
February 2019
8 Reads

Diagnostic value of electrocardiogram in cardiac tamponade.

Med J Malaysia 2019 02;74(1):51-56

Sultanah Aminah Hospital, Department of Cardiology, Johor Bahru, Johor, Malaysia.

Introduction: We aim to study the diagnostic value of electrocardiogram (ECG) in cardiac tamponade.

Methods: This study was a single centre, retrospective casecontrol study. We recruited 42 patients diagnosed with cardiac tamponade of various aetiologies confirmed by transthoracic echocardiography and 100 controls between January 2011 and December 2015. Read More

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February 2019
9 Reads

Neutrophil-lymphocyte ratio: A prognostic tool in patients with in-hospital cardiac arrest.

World J Crit Care Med 2019 Feb 21;8(2):9-17. Epub 2019 Feb 21.

Department of Cardiovascular Medicine, Ascension-St John Hospital and Medical Center, Detroit, MI 48236, United States.

Background: In-hospital cardiac arrest (IHCA) portends a poor prognosis and survival to discharge rate. Prognostic markers such as interleukin-6, S-100 protein and high sensitivity C reactive protein have been studied as predictors of adverse outcomes after return of spontaneous circulation (ROSC); however; these variables are not routine laboratory tests and incur additional cost making them difficult to incorporate and less attractive in assessing patient's prognosis. The neutrophil-lymphocyte ratio (NLR) is a marker of adverse prognosis for many cardiovascular conditions and certain types of cancers and sepsis. Read More

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https://www.wjgnet.com/2220-3141/full/v8/i2/9.htm
Publisher Site
http://dx.doi.org/10.5492/wjccm.v8.i2.9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6388309PMC
February 2019
35 Reads

Pulse Arrival Time and Pulse Interval as Accurate Markers to Detect Mechanical Alternans.

Ann Biomed Eng 2019 May 12;47(5):1291-1299. Epub 2019 Feb 12.

Department of Mechanical Engineering, University College London, London, UK.

Mechanical alternans (MA) is a powerful predictor of adverse prognosis in patients with heart failure and cardiomyopathy, but its use remains limited due to the need of invasive continuous arterial pressure recordings. This study aims to assess novel cardiovascular correlates of MA in the intact human heart to facilitate affordable and non-invasive detection of MA and advance our understanding of the underlying pathophysiology. Arterial pressure, respiration, and ECG were recorded in 12 subjects with healthy ventricles during voluntarily controlled breathing at different respiratory rate, before and after administration of beta-blockers. Read More

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http://dx.doi.org/10.1007/s10439-019-02221-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6453876PMC
May 2019
20 Reads

Mechanistic insights from targeted molecular profiling of repolarization alternans in the intact human heart.

Europace 2019 Jun;21(6):981-989

Institute of Cardiovascular Science, University College London, London, UK.

Aims: Action potential duration (APD) alternans is an established precursor or arrhythmia and sudden cardiac death. Important differences in fundamental electrophysiological properties relevant to arrhythmia exist between experimental models and the diseased in vivo human heart. To investigate mechanisms of APD alternans using a novel approach combining intact heart and cellular cardiac electrophysiology in human in vivo. Read More

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http://dx.doi.org/10.1093/europace/euz007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6545501PMC
June 2019
29 Reads

Supraventricular tachycardia with QRS and cycle length alternans. What is the diagnosis?

Hellenic J Cardiol 2019 Sep - Oct;60(5):331-333. Epub 2019 Jan 23.

2(nd) Department of Cardiology, General Hospital of Nikea-Piraeus "Agios Panteleimon", D. Mantouvalou 3, 18454, Piraeus, Greece.

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http://dx.doi.org/10.1016/j.hjc.2019.01.006DOI Listing
January 2019
9 Reads

Acute Influenza Infection Presenting with Cardiac Tamponade: A Case Report and Review of Literature.

Perm J 2019 ;23:18-104

Department of Pulmonary and Critical Care, University of Arkansas for Medical Sciences Medical Center, Little Rock.

Introduction: Cardiac complications associated with influenza infection can occur either via a direct effect of the virus on the heart or through exacerbation of preexisting cardiovascular disease. We present a case of a 57-year-old man with acute influenza infection complicated by pericardial effusion and cardiac tamponade.

Case Presentation: A 57-year-old white man presented to the Emergency Department with sudden onset of severe, nonexertional, retrosternal, pressure-like chest pain for a few hours and with fever and muscle aches for 2 days. Read More

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http://dx.doi.org/10.7812/TPP/18-104DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6326557PMC
June 2019
9 Reads

Mechanistic insight into spontaneous transition from cellular alternans to arrhythmia-A simulation study.

PLoS Comput Biol 2018 11 30;14(11):e1006594. Epub 2018 Nov 30.

Biological Physics Group, School of Physics & Astronomy, The University of Manchester, Manchester, United Kingdom.

Cardiac electrical alternans (CEA), manifested as T-wave alternans in ECG, is a clinical biomarker for predicting cardiac arrhythmias and sudden death. However, the mechanism underlying the spontaneous transition from CEA to arrhythmias remains incompletely elucidated. In this study, multiscale rabbit ventricular models were used to study the transition and a potential role of INa in perpetuating such a transition. Read More

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http://dx.doi.org/10.1371/journal.pcbi.1006594DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6291170PMC
November 2018
11 Reads

Concomitant SK current activation and sodium current inhibition cause J wave syndrome.

JCI Insight 2018 11 15;3(22). Epub 2018 Nov 15.

Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA.

The mechanisms of J wave syndrome (JWS) are incompletely understood. Here, we showed that the concomitant activation of small-conductance calcium-activated potassium (SK) current (IKAS) and inhibition of sodium current by cyclohexyl-[2-(3,5-dimethyl-pyrazol-1-yl)-6-methyl-pyrimidin-4-yl]-amine (CyPPA) recapitulate the phenotypes of JWS in Langendorff-perfused rabbit hearts. CyPPA induced significant J wave elevation and frequent spontaneous ventricular fibrillation (SVF), as well as sinus bradycardia, atrioventricular block, and intraventricular conduction delay. Read More

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https://insight.jci.org/articles/view/122329
Publisher Site
http://dx.doi.org/10.1172/jci.insight.122329DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6302939PMC
November 2018
43 Reads

Electrical Alternans in Disguise-A Curious Case of Atrial Flutter.

JAMA Intern Med 2018 Dec;178(12):1704-1705

Department of Medicine, University of California, San Francisco, San Francisco.

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http://dx.doi.org/10.1001/jamainternmed.2018.5291DOI Listing
December 2018
11 Reads

Calcium in the Pathophysiology of Atrial Fibrillation and Heart Failure.

Front Physiol 2018 4;9:1380. Epub 2018 Oct 4.

Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.

Atrial fibrillation (AF) is commonly associated with heart failure. A bidirectional relationship exists between the two-AF exacerbates heart failure causing a significant increase in heart failure symptoms, admissions to hospital and cardiovascular death, while pathological remodeling of the atria as a result of heart failure increases the risk of AF. A comprehensive understanding of the pathophysiology of AF is essential if we are to break this vicious circle. Read More

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https://www.frontiersin.org/article/10.3389/fphys.2018.01380
Publisher Site
http://dx.doi.org/10.3389/fphys.2018.01380DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6180171PMC
October 2018
55 Reads

Geometry-Dependent Arrhythmias in Electrically Excitable Tissues.

Cell Syst 2018 10 3;7(4):359-370.e6. Epub 2018 Oct 3.

Department of Physics, Harvard University, Cambridge, MA 02138, USA; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute, Cambridge, MA 02138, USA. Electronic address:

Little is known about how individual cells sense the macroscopic geometry of their tissue environment. Here, we explore whether long-range electrical signaling can convey information on tissue geometry to individual cells. First, we studied an engineered electrically excitable cell line. Read More

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http://dx.doi.org/10.1016/j.cels.2018.08.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6204347PMC
October 2018
15 Reads

Synchronization of Triggered Waves in Atrial Tissue.

Biophys J 2018 09 18;115(6):1130-1141. Epub 2018 Aug 18.

Department of Medicine (Cardiology) and The Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois.

When an atrial cell is paced rapidly, calcium (Ca) waves can form on the cell boundary and propagate to the cell interior. These waves are referred to as "triggered waves" because they are initiated by Ca influx from the L-type Ca channel and occur during the action potential. However, the consequences of triggered waves in atrial tissue are not known. Read More

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http://dx.doi.org/10.1016/j.bpj.2018.08.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6139957PMC
September 2018
43 Reads

Pericardial effusion and electrical alternans.

QJM 2019 Feb;112(2):135-136

Department of Internal Medicine, Post Graduate Institute of Medical Education and Research, 4th floor, F block, Chandigarh, India.

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http://dx.doi.org/10.1093/qjmed/hcy191DOI Listing
February 2019
11 Reads

Clinical Outcomes and Modes of Death in Timothy Syndrome: A Multicenter International Study of a Rare Disorder.

JACC Clin Electrophysiol 2018 04 6;4(4):459-466. Epub 2017 Nov 6.

Department of Pediatrics, Division of Pediatric Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania. Electronic address:

Objectives: The objective of this study was to evaluate contemporary clinical outcomes and identify triggers for arrhythmias or sudden death in an international cohort of Timothy Syndrome (TS) patients including those with novel TS-associated CACNA1C mutations.

Background: TS is an extremely rare genetic disorder of the L-type cardiac channel Ca1.2 encoded by CACNA1C. Read More

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http://dx.doi.org/10.1016/j.jacep.2017.08.007DOI Listing
April 2018
26 Reads

Rapid Fire: Pericardial Effusion and Tamponade.

Emerg Med Clin North Am 2018 Aug 11;36(3):557-565. Epub 2018 Jun 11.

Department of Emergency Medicine, University of Maryland Medical Center, 110 South Paca Street, 6th Floor, Suite 200, Baltimore, MD 21201, USA. Electronic address:

One of the most common causes of pericardial effusion in the Western world is malignancy. Emergency physicians must maintain vigilance in suspecting pericardial effusion and tamponade in patients with known or suspected malignancy who present with tachycardia, dyspnea, and hypotension. Diagnosis can be expedited by key physical examination, electrocardiogram, and sonographic findings. Read More

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http://dx.doi.org/10.1016/j.emc.2018.04.004DOI Listing
August 2018
14 Reads

Massive pericardial effusion: A rare and easily missed finding in myocardial perfusion scintigraphy.

World J Nucl Med 2018 Jul-Sep;17(3):198-200

Nuclear Medicine Unit, Queen Elizabeth Hospital, Kowloon, Hong Kong, China.

A 72-year-old gentleman underwent myocardial perfusion scintigraphy (MPS) for sinus tachycardia of unknown cause. Baseline electrocardiography (ECG) showed sinus tachycardia and electrical alternans. Thallium-201 stress-redistribution MPS was performed with dipyridamole stress. Read More

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http://dx.doi.org/10.4103/wjnm.WJNM_39_17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6034550PMC
July 2018
10 Reads

Total electrical alternans in a patient with malignant pericardial tamponade.

BMJ Case Rep 2018 Jul 19;2018. Epub 2018 Jul 19.

Internal Medicine, Academic Medical Center, Amsterdam, The Netherlands.

We present a case of a 59-year-old man with acute abdominal pain and progressive shortness of breath. A focused assessment with sonography for trauma scan showed free fluid in the hepatorenal recess and in the recto-uterine recess. Later, due to clinical deterioration and the differential possibility of a pulmonary embolism or aortic dissection, a CT scan was performed which revealed large pericardial effusion. Read More

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http://casereports.bmj.com/lookup/doi/10.1136/bcr-2018-22477
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http://dx.doi.org/10.1136/bcr-2018-224771DOI Listing
July 2018
31 Reads

Reduced T wave alternans in heart failure responders to cardiac resynchronization therapy: Evidence of electrical remodeling.

PLoS One 2018 28;13(6):e0199637. Epub 2018 Jun 28.

Peter Munk Cardiac Center, Division of Cardiology, University Health Network, Toronto, ON, Canada.

Background: T-wave alternans (TWA), a marker of electrical instability, can be modulated by cardiac resynchronization therapy (CRT). The relationship between TWA and heart failure response to CRT has not been clearly defined.

Methods And Results: In 40-patients (age 65±11 years, left ventricular ejection-fraction [LVEF] 23±7%), TWA was evaluated prospectively at median of 2 months (baseline) and 8 months (follow-up) post-CRT implant. Read More

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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0199637PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6023131PMC
December 2018
14 Reads

Mechanical perturbation control of cardiac alternans.

Phys Rev E 2018 May;97(5-1):052407

Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, Canada T6G 2V4.

Cardiac alternans is a disturbance in heart rhythm that is linked to the onset of lethal cardiac arrhythmias. Mechanical perturbation control has been recently used to suppress alternans in cardiac tissue of relevant size. In this control strategy, cardiac tissue mechanics are perturbed via active tension generated by the heart's electrical activity, which alters the tissue's electric wave profile through mechanoelectric coupling. Read More

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http://dx.doi.org/10.1103/PhysRevE.97.052407DOI Listing
May 2018
9 Reads

Targeted ablation of cardiac sympathetic neurons improves ventricular electrical remodelling in a canine model of chronic myocardial infarction.

Europace 2018 12;20(12):2036-2044

Department of Cardiology, Renmin Hospital of Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China.

Aims: The purpose of this study was to evaluate the cardiac electrophysiologic effects of targeted ablation of cardiac sympathetic neurons (TACSN) in a canine model of chronic myocardial infarction (MI).

Methods And Results: Thirty-eight anaesthetized dogs were randomly assigned into the sham-operated, MI, and MI-TACSN groups, respectively. Myocardial infarction-targeted ablation of cardiac sympathetic neuron was induced by injecting cholera toxin B subunit-saporin compound in the left stellate ganglion (LSG). Read More

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http://dx.doi.org/10.1093/europace/euy090DOI Listing
December 2018
23 Reads

True vs. pseudo-electrical ventricular alternans sustained by ventricular premature complexes.

Herzschrittmacherther Elektrophysiol 2018 Jun;29(2):233-235

Biotronik, Berlin, Germany.

This report describes a form of electrical ventricular alternans sustained by ventricular premature complexes (VPC). Alternans was associated with a constant heart rate (RR interval) and was therefore considered to be either a form of classic or true alternans or a mimic of the configuration seen in true alternans from other causes. In contrast, VPC-induced pseudo-alternans is characterized by an inconstant heart rate (RR interval). Read More

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http://dx.doi.org/10.1007/s00399-018-0572-0DOI Listing
June 2018
11 Reads

Utility of heart rate turbulence and T-wave alternans to assess risk for readmission and cardiac death in hospitalized heart failure patients.

J Cardiovasc Electrophysiol 2018 09 6;29(9):1257-1264. Epub 2018 Jun 6.

Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan.

Background: Heart failure (HF) patients have a higher risk of recurrent HF and cardiac death, and electrical remodeling is considered to be an important factor for HF progression. The present study aimed to validate the utility of electrocardiogram and Holter monitoring for the risk stratification of HF patients.

Methods: Our study comprised 215 patients (144 males, mean age 62 years) who had been hospitalized due to acute decompensated HF. Read More

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http://dx.doi.org/10.1111/jce.13639DOI Listing
September 2018
37 Reads

Disruption of neonatal cardiomyocyte physiology following exposure to bisphenol-a.

Sci Rep 2018 05 9;8(1):7356. Epub 2018 May 9.

Sheikh Zayed Institute for Pediatric and Surgical Innovation, Children's National Health System, Washington, USA.

Bisphenol chemicals are commonly used in the manufacturing of polycarbonate plastics, polyvinyl chloride plastics, resins, and thermal printing applications. Humans are inadvertently exposed to bisphenols through contact with consumer products and/or medical devices. Recent reports have shown a link between bisphenol-a (BPA) exposure and adverse cardiovascular outcomes; although these studies have been limited to adult subjects and models. Read More

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http://dx.doi.org/10.1038/s41598-018-25719-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5943481PMC
May 2018
11 Reads
5.080 Impact Factor

Electrical stimulation-based renal nerve mapping exacerbates ventricular arrhythmias during acute myocardial ischaemia.

J Hypertens 2018 06;36(6):1342-1350

Objective: Blood pressure elevation in response to transient renal nerve stimulation (RNS) has been used to determine the ablation target and endpoint of renal denervation. This study aimed to evaluate the safety of transient RNS in canines with normal or ischaemic hearts.

Methods: In ten normal (Group 1) and six healed myocardial infarction (HMI) (Group 2) canines, a large-tip catheter was inserted into the left or right renal artery to perform transient RNS. Read More

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http://dx.doi.org/10.1097/HJH.0000000000001712DOI Listing
June 2018
20 Reads
4.720 Impact Factor

Sympathetic Nervous Regulation of Calcium and Action Potential Alternans in the Intact Heart.

Front Physiol 2018 23;9:16. Epub 2018 Jan 23.

School of Cardiovascular Medicine and Sciences, King's College London, United Kingdom.

Arrhythmogenic cardiac alternans are thought to be an important determinant for the initiation of ventricular fibrillation. There is limited information on the effects of sympathetic nerve stimulation (SNS) on alternans in the intact heart and the conclusions of existing studies, focused on investigating electrical alternans, are conflicted. Meanwhile, several lines of evidence implicate instabilities in Ca handling, not electrical restitution, as the primary mechanism underpinning alternans. Read More

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http://dx.doi.org/10.3389/fphys.2018.00016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5787134PMC
January 2018
11 Reads