DOCSLIB.ORG

Atrioventricular Conduction in Patients with Clinical Indications for Transvenous Cardiac Pacing1

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Atrioventricular Conduction in Patients with Clinical Indications for Transvenous Cardiac Pacing1 British Heart Journal, 1975, 37, 583-592. Atrioventricular conduction in patients with clinical indications for transvenous cardiac pacing1 Stafford I. Cohen, L. Kent Smith, Julian M. Aoresty, Panagiotis Voukydis, and Eugene Morkin From the Cardiac Unit, Department of Medicine, Beth Israel Hospital and Harvard Medical School, Boston, Massachusetts, U.S.A. Eighty patients with clinical indications for cardiac pacing had atrioventricular conduction analysed by His bundle study. The indicationsfor cardiac pacing included high grade atrioventricular block, sick sinus node syndrome without tachycardia, bradycardia-tachycardia syndrome, unstable bilateral bundle-branch block, and uncontrolled ventricular irritability. Complete heart block, Wenckebach block (Mobitz I), and 2:i block were notedproximal and distal to the His bundle. Mobitz II block only occurred distal to the His bundle. Ofspecial interest were the high incidence ofdistal conduction abnormalities by His bundle analysis (40/80, 5o%), the re-establishment ofnormal atrio- ventricular conduction in acutely ill patients with recent evidence of heart block, and the high incidence of intraventricular conduction disturbances on standard electrocardiogram (48/8o, 60%). Intensive study of atrioventricular conduction by occurring electrophysiological data in this large His bundle analysis has been performed in a variety group of patients in clinical need of pacemakers of patient populations. In many instances studies constitutes the substance of this report. The data were electively undertaken in patients who had should be representative of the cardiac conduction never been threatened by a compromising cardiac abnormalities which present in a general hospital. arrhythmia. In addition, abnormalities of atrio- ventricular conduction were frequently achieved by Subjects and methods pacemaker-induced acceleration of the atrial rate. Atrioventricular conduction was studied in 8o patients The purpose of this study was to characterize atrio- referred for temporary or permanent cardiac pacing. ventricular conduction in a group of patients who Temporary transvenous pacing was performed via the had clinical indications for a cardiac pacemaker. transfemoral route with a No. 5 bipolar catheter. The ring electrodes were 2 mm in width and spaced I cm Atrioventricular conduction was analysed by His apart. His bundle electrograms were obtained by stan- bundle electrogram in 80 patients who were referred dard methods and were recorded on an 8-channel for transvenous cardiac pacing. The clinical indi- Electronics for Medicine oscilloscope recorder. Acutely cations for cardiac pacing included third degree ill patients had temporary pacemakers inserted and block, second degree block, sick sinus node syn- electrophysiological study conducted in the cardiac drome without tachycardia, bradycardia-tachycardia catheterization laboratory or the intensive care unit. syndrome, unstable bilateral bundle-branch block, Study in the latter area was facilitated by the use of a and uncontrolled ventricular irritability. Data per- fluoroscopic bed and image intensifier. All permanent taining to atrioventricular conduction were obtained pacemakers were implanted in the cardiac catheteriza- during the course of transfemoral venous pace- tion laboratory. Patients who required permanent pace- maker revision or replacement had a No. 5 bipolar maker insertion. The characteristics of atrioven- temporary transfemoral catheter positioned for electrical tricular conduction were noted as well as standard control during the procedure. electrocardiographic evidence of remote or current Bipolar electrograms were obtained by standard intraventricular conduction disturbances. methods which defined atrial excitation (A), His bundle The presentation of the analysis of the naturally excitation (H), and ventricular excitation (V) (Scherlag et al., I969, I970; Damato et al., I969; Damato and Received 28 October I974. Lau, 1970; Scherlag, Samet, and Helfant, I972). His ISupported in part by a training grant from the National bundle electrograms were validated either by an increase Heart and Lung Institute. in the AH interval during spontaneous or induced atrial 584 Cohen, Smith, Aoresty, Voukydis, and Morkin TABLE I TABLE I (Cont'd) Case Sex Age His bundle electrogram Case Sex Age His bundle electrogram No. AH (ms) HV (ms) No. AH (ms) HV (ms) Third degree block: absent at study Sick sinus syndrome: without tachycardia-cont'd I M 55 55 95 55 F 79 II2 56 2 F 84 IIO 45 56 M 83 I50 55 3 F 84 I30 35 57 F 78 170 46 4 F 74 250 47 58 M 76 I85 47 5 M 8i 93 IOO, Mobitz I 59 M 8o II5 40 6 F 75 66 5i, Mobitz I 60 M 86 I26 43 7 F 7I I50 35 6i F 73 i60 58 8 M 63 I22 II4 62 F 8i I73 62 9 F 85 I25 40 63 M 70 88 45 IO M 56 62 47 II M 69 I50 38 Bradycardia-tachycardia syndrome 12 F 74 70 68 64 F 70 82 34 I3 M 65 I35 65 65 F 72 120 57 66 F 72 I60 38 Third degree block: present at study 67 M 8i 80 35 I4 F 8i 95 68 F 73 134 66 I5 F 84 100 i6 M 8i 200 Bilateral bundle-branch block 17 M 83 - 69 M 86 258 66 i8 M 74 87 70 M 78 I40 80 I9 F 75 66 7I M 75 I97 54 20 M 77 72 M 83 I05 42 2I M 80 I30 73 M 85 IOO 46 22 M 76 I27 74 F 63 94 35 23 M 73 II5 75 M 72 98 49 24 M 76 88 76 M 6i I06 40 25 F 77 130 77 M 6i 95 54 26 M 70 27 F 75 Control of ventricular ectopia 28 F 74 78 F 78 io8 58 29 M 68 92 79 M 76 i6o 35 30 M 86 80 M 78 I05 40 31 M 6i 145 Second degree block: absent at study 32 M 60 125 70 premature beats (Scherlag et al., I969) or by His bundle 33 F 86 I05 I40 pacing (Scherlag et al., 1972; Narula, Scherlag, and 34 F 79 120 40 Samet, 1970b). The AH interval generally delineated F 35 84 125 atrioventricular node conduction time, the normal range Second degree block: present at study of which is 50 to 120 ms. Measurements were made 36 M 68 ioi 67, 2:I from the onset of the A wave to the first clear deflection 37 M 86 253, Mobitz I 49 of the H wave. Prolongation of atrioventricular node 38 F 80 232, Mobitz I 45 conduction time was defined as first degree block of the 39 F 83 145,2:1 4I atrioventricular node. 40 M 77 102 75, 2:1 The HV interval delineated His-Purkinje conduction 41 F 80 87 87, 2:I time, the normal range of which was taken as 35 to 54 ms 42 F 8o 148 53, 2:I (Kuppersmith, Krongrad, and Waldo, I973). Measure- 43 F 79 I20,2:I 53 44 M 7I 62 57, Mobitz II ments were made from the first clear deflection of the H 45 M 6i 66 77, Mobitz I wave to the earliest onset of ventricular excitation pre- 46 F 84 88 75, Mobitz I senting in one of several sampled standard electro- 47 F 84 99 80, Mobitz I cardiographic leads or the bipolar electrograms (V 48 F 65 ioi IIO, Mobitz I wave). The HV interval is one measurement of con- 49 M 43 120, Mobitz I 58 duction through the distal specialized conduction system. 50 M 66 375, Mobitz I 47 Prolongation of the HV interval was defined as first Sick sinus syndrome: without tachycardia degree block of the intraventricular conduction system. were 5I M 64 87 34 All available electrocardiograms reviewed for 52 M 72 150 40 evidence of intraventricular conduction abnormality in 53 F 73 94 35 the bundle-branch system. Abnormal conduction in the 54 F 69 123 38 right bundle-branch, left bundle-branch, anterior divi- sion of the left bundle-branch, and posterior division of Atrioventricular conduction in patients with clinical indications for transvenous cardiac pacing 585 TABLE 2 Group No. of Normal I0 block 20 block 30 block patients atrioven- tricular AVN IVC AVN IVC AVN IVC conduction Mobitz I 30 block absent at study I3 2 5 2 2 2) (2 30 block present at study i8 6 7 5) (5 Sick sinus syndrome I3 4 5 I 3) (3 Bradycardia-tachycardia 5 2 I I syndrome Bilateral bundle-branch block 9 6 I 23 -(2 Suppression of ventricular 3 I I I ectopia Group No of Normal I° block 2° block 2:I block patients atrioven- tricular AVN IVC AVN IVC AVN IVC conduction Mobitz Mobitz Mobitz Mobitz I II I II 2° block absent at study 4 I I 2) (2 20 block present at study 15 3 4 I 2 3 I) ( )-( This symbol indicates more than one abnormality. The number of patients with the combined abnormality are noted by the number on the open ends of the symbol. AVN = Atrioventricular node, IVC = Intraventricular conduction. the left bundle-branch, respectively, result in right study (Fig. I and 2). First degree block of the atrio- bundle-branch block, left bundle-branch block, left axis ventricular node was present in 5 patients. First deviation, and right axis deviation (Rosenbaum, Elizari, degree block in the distal conduction system was and Lazzari, I970; Cohen et al., I968). Combined dis- present in 2 patients. Combined first degree block turbances in more than one conducting pathway can be in the atrioventricular node as well as in the distal recognized by combinations ofthese features. was 2 The 80 patients had an average age of 75 years, with specialized conduction system present in the 44 men averaging 72 years and the 36 women aver- patients. Wenckebach phenomenon (Mobitz I block) aging 77 years. The patients were grouped as follows: was present in the distal conducting system in 2 transient third degree block absent at study (I3), third patients.
Load more

Recommended publications
  • 16 the Heart
    Physiology Unit 3 CARDIOVASCULAR PHYSIOLOGY: THE HEART Cardiac Muscle • Conducting system – Pacemaker cells – 1% of cells make up the conducting system – Specialized group of cells which initiate the electrical current which is then conducted throughout the heart • Myocardial cells (cardiomyocytes) • Autonomic Innervation – Heart Rate • Sympathetic and Parasympathetic regulation • �1 receptors (ADRB1), M-ACh receptors – Contractility • Sympathetic stimulus • Effects on stroke volume (SV) Electrical Synapse • Impulses travel from cell to cell • Gap junctions – Adjacent cells electrically coupled through a channel • Examples – Smooth and cardiac muscles, brain, and glial cells. Conducting System of the Heart • SA node is the pacemaker of the heart – Establishes heart rate – ANS regulation • Conduction Sequence: – SA node depolarizes – Atria depolarize – AV node depolarizes • Then a 0.1 sec delay – Bundle of His depolarizes – R/L bundle branches depolarize – Purkinje fibers depolarize Sinus Rhythm: – Ventricles depolarize Heartbeat Dance Conduction Sequence Electrical Events of the Heart • Electrocardiogram (ECG) – Measures the currents generated in the ECF by the changes in many cardiac cells • P wave – Atrial depolarization • QRS complex – Ventricular depolarization – Atrial repolarization • T wave – Ventricular repolarization • U Wave – Not always present – Repolarization of the Purkinje fibers AP in Myocardial Cells • Plateau Phase – Membrane remains depolarized – L-type Ca2+ channels – “Long opening” calcium channels – Voltage gated
    [Show full text]
  • View Pdf Copy of Original Document
    Phenotype definition for the Vanderbilt Genome-Electronic Records project Identifying genetics determinants of normal QRS duration (QRSd) Patient population: • Patients with DNA whose first electrocardiogram (ECG) is designated as “normal” and lacking an exclusion criteria. • For this study, case and control are drawn from the same population and analyzed via continuous trait analysis. The only difference will be the QRSd. Hypothetical timeline for a single patient: Notes: • The study ECG is the first normal ECG. • The “Mildly abnormal” ECG cannot be abnormal by presence of heart disease. It can have abnormal rate, be recorded in the presence of Na-channel blocking meds, etc. For instance, a HR >100 is OK but not a bundle branch block. • Y duration = from first entry in the electronic medical record (EMR) until one month following normal ECG • Z duration = most recent clinic visit or problem list (if present) to one week following the normal ECG. Labs values, though, must be +/- 48h from the ECG time Criteria to be included in the analysis: Criteria Source/Method “Normal” ECG must be: • QRSd between 65-120ms ECG calculations • ECG designed as “NORMAL” ECG classification • Heart Rate between 50-100 ECG calculations • ECG Impression must not contain Natural Language Processing (NLP) on evidence of heart disease concepts (see ECG impression. Will exclude all but list below) negated terms (e.g., exclude those with possible, probable, or asserted bundle branch blocks). Should also exclude normalization negations like “LBBB no longer present.”
    [Show full text]
  • New Emergency Room Requirement for Hospital and Autopay List of Diagnosis Codes
    Provider update New emergency room requirement for hospitals Dell Children’s Health Plan reviewed our emergency room (ER) claims data and identified numerous reimbursements for services with diagnoses that are not indicative of urgent or emergent conditions. As a managed care organization, we promote the provision of services in the most appropriate setting and reinforce the need for members to coordinate care with their PCP unless the injury or sudden onset of illness requires immediate medical attention. Effective on or after August 1, 2020, for nonparticipating hospitals and on or after October 1, 2020, for participating hospitals, Dell Children’s Health Plan will only process an ER claim for a hospital as emergent and reimburse at the applicable contracted rate or valid out‐ of‐network Medicaid fee‐for‐service rate when a diagnosis from a designated auto‐pay list is billed as the primary diagnosis on the claim. If the primary diagnosis is not on the auto‐pay list, the provider must submit medical records with the claim. Upon receipt, the claim and records will be reviewed by a prudent layperson standard to determine if the presenting symptoms qualify the patient’s condition as emergent. If the reviewer confirms the visit was emergent, according to the prudent layperson criteria, the claim will pay at the applicable contracted rate or valid out‐of‐network Medicaid fee‐for‐service rate. If it is determined to be nonemergent, the claim will pay a triage fee. In the event a claim from a hospital is submitted without a diagnosis from the auto‐pay list as the primary diagnosis and no medical records are attached, the claim for the ER visit will automatically pay a triage fee.
    [Show full text]
  • Medicare National Coverage Determinations Manual, Part 1
    Medicare National Coverage Determinations Manual Chapter 1, Part 1 (Sections 10 – 80.12) Coverage Determinations Table of Contents (Rev. 10838, 06-08-21) Transmittals for Chapter 1, Part 1 Foreword - Purpose for National Coverage Determinations (NCD) Manual 10 - Anesthesia and Pain Management 10.1 - Use of Visual Tests Prior to and General Anesthesia During Cataract Surgery 10.2 - Transcutaneous Electrical Nerve Stimulation (TENS) for Acute Post- Operative Pain 10.3 - Inpatient Hospital Pain Rehabilitation Programs 10.4 - Outpatient Hospital Pain Rehabilitation Programs 10.5 - Autogenous Epidural Blood Graft 10.6 - Anesthesia in Cardiac Pacemaker Surgery 20 - Cardiovascular System 20.1 - Vertebral Artery Surgery 20.2 - Extracranial - Intracranial (EC-IC) Arterial Bypass Surgery 20.3 - Thoracic Duct Drainage (TDD) in Renal Transplants 20.4 – Implantable Cardioverter Defibrillators (ICDs) 20.5 - Extracorporeal Immunoadsorption (ECI) Using Protein A Columns 20.6 - Transmyocardial Revascularization (TMR) 20.7 - Percutaneous Transluminal Angioplasty (PTA) (Various Effective Dates Below) 20.8 - Cardiac Pacemakers (Various Effective Dates Below) 20.8.1 - Cardiac Pacemaker Evaluation Services 20.8.1.1 - Transtelephonic Monitoring of Cardiac Pacemakers 20.8.2 - Self-Contained Pacemaker Monitors 20.8.3 – Single Chamber and Dual Chamber Permanent Cardiac Pacemakers 20.8.4 Leadless Pacemakers 20.9 - Artificial Hearts And Related Devices – (Various Effective Dates Below) 20.9.1 - Ventricular Assist Devices (Various Effective Dates Below) 20.10 - Cardiac
    [Show full text]
  • Vectorcardiographic Study of Aberrant Conduction' of Intraventricular Block
    Br Heart J: first published as 10.1136/hrt.38.6.549 on 1 June 1976. Downloaded from British Heart journal, 1976, 38, 549-557. Vectorcardiographic study of aberrant conduction' Anterior displacement of QRS: another form of intraventricular block H. E. Kulbertus, F. de Leval-Rutten, and P. Casters From the Division of Cardiology, Institute of Medicine, University of Liege School of Medicine, Liege, Belgium Aberrant ventricular conduction was induced in 44 subjects by introduction of atrialpremature beats through a transvenous catheter-electrode. Multiple patterns of aberrant ventricular conduction were obtained in 32 patients and, in the whole group, 116 different configurations were recorded. Of these, 104 showed a classical pattern of mono- or biventricular conduction disturbance. The pattertn frequencies were as follows: right bundle-branch block, 28; left anterior hemiblock combined with right bundle-branch block, 21; left anterior hemiblock, 17; left posterior hemiblock combined with right bundle-branch block, 12; left posterior hemiblock, 10; complete left bundle-branch block, 10; and incomplete left bundle-branch block, 6. The remaining 12 configurations could not be classified into the usual categories of intraventricular blocks. In 7 of them, the alterations only consisted of trivial modifications of the QRS contour. In the other 5 instances, aberrant conduction manifested itself by a conspicuous anterior displacement of the QRS loop, with increased duration of anteriorforces. The latter observation is worthy of notice, as it indicates that, in the differential diagnosis of the vectorcardiographic pattern characterized by prominent anteriorforces, conduction disturbances should http://heart.bmj.com/ be considered a possible aetiological factor in addition to right ventricular hypertrophy, and true posterior wall myocardial infarction.
    [Show full text]
  • CMS Limitations Guide - Cardiovascular Services
    CMS Limitations Guide - Cardiovascular Services Starting October 1, 2015, CMS will update their It is the responsibility of the provider to code to the existing medical necessity limitations on tests and highest level specified in the ICD-10-CM. The correct procedures to correspond to ICD-10 codes. This use of an ICD-10-CM code listed below does not limitations guide provides you with the latest assure coverage of a service. The service must be changes. reasonable and necessary in the specific case and must meet the criteria specified in this This guide is not an all-inclusive list of National determination. Coverage Documents (NCD) and Local Coverage Documents (LCD). You can search by LCD or NCD or We will continue to update this list as new CMS keyword and region on the CMS website at: limitations are announced. You can always find the https://www.cms.gov/medicare-coverage- most current list at: database/overview-and-quick- www.munsonhealthcare.org/medicalnecessity. search.aspx?clickon=search. If you have any questions, please contact Kari Smith, CMS will deny payment if the correct diagnosis Office Coordinator, at (231) 935-2296, or Karen codes are not entered on the order form, and your Popa, Director, Patient Access Services, at (231) 935- 7493. patient’s test or procedure will not be covered. We compiled this information in one location to make it easier for you to find the proper codes for medically necessary diagnoses. CMS Limitations Guide – Cardiovascular Services (L34636) Electrocardiographic (EKG or ECG) Monitoring (Holter
    [Show full text]
  • The Miniaturization of Cardiac Implantable Electronic Devices: Advances in Diagnostic and Therapeutic Modalities
    micromachines Review The Miniaturization of Cardiac Implantable Electronic Devices: Advances in Diagnostic and Therapeutic Modalities Richard G. Trohman *, Henry D. Huang and Parikshit S. Sharma Section of Electrophysiology, Arrhythmia and Pacemaker Services, Division of Cardiology, Department of Internal Medicine, Rush University Medical Center, Chicago, IL 60612, USA; [email protected] (H.D.H.); [email protected] (P.S.S.) * Correspondence: [email protected]; Tel.: +1-312-942-2887 Received: 26 August 2019; Accepted: 17 September 2019; Published: 21 September 2019 Abstract: The Fourth Industrial Revolution, characterized by an unprecedented fusion of technologies that is blurring the lines between the physical, digital, and biological spheres, continues the trend to manufacture ever smaller mechanical, optical and electronic products and devices. In this manuscript, we outline the way cardiac implantable electronic devices (CIEDs) have evolved into remarkably smaller units with greatly enhanced applicability and capabilities. Keywords: implantable cardioverter defibrillators; cardiac pacing; cardiac resynchronization therapy; implantable heart failure sensor; implantable loop recorder 1. Introduction The Fourth Industrial Revolution [1], characterized by an unprecedented fusion of technologies that is blurring the lines between the physical, digital, and biological spheres, continues the trend to manufacture ever smaller mechanical, optical and electronic products and devices [2]. In this manuscript, we outline the way cardiac implantable electronic devices (CIEDs) have evolved into remarkably smaller units with greatly enhanced applicability and capabilities. 2. Prevention of Sudden Death The current annual incidence of sudden cardiac death in the United States is in the range of 180,000 to 450,000 per year [3,4]. Although the prevalence of malignant ventricular arrhythmias as the etiology has declined, they remain the most common cause of cardiac arrest [3].
    [Show full text]
  • An Interesting Case of Acute Asymptomatic Lead Perforation of a Permanent Cardiac Pacemaker
    Open Access Case Report DOI: 10.7759/cureus.13334 An Interesting Case of Acute Asymptomatic Lead Perforation of a Permanent Cardiac Pacemaker Anunay Gupta 1 , Sourabh Agstam 1 , Tushar Agarwal 1 , Sunil Verma 2 1. Cardiology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, IND 2. Cardiology, All India Institute of Medical Sciences, New Delhi, IND Corresponding author: Sunil Verma, [email protected] Abstract Acute complications of pacemaker implantation such as lead dislodgement, pneumothorax, and myocardial perforation are not uncommon. Management of these usually requires reintervention. We herein describe lead perforation after a single chamber pacemaker implantation, which was successfully managed conservatively. This case underscores that vigilant monitoring post lead perforation can avoid a redo procedure. Categories: Cardiac/Thoracic/Vascular Surgery, Cardiology, Radiology Keywords: impending pericardial effusion, pacemaker lead perforation, pacemaker lead displacement, pacemaker complication Introduction Acute complications such as lead dislodgement, pneumothorax, and myocardial perforation are not uncommon after pacemaker implantation. Lead perforation can be either early or late, and lead can perforate through the myocardium, into the epicardial space, pericardium, or chest wall [1]. Such perforations can sometimes be clinically occult and not accompanied by symptoms such as pain or pericardial effusion [2]. A chest X-ray in two different views is useful in demonstrating perforation but is limited by its inability to differentiate between the ventricular cavity, myocardium, and pericardium. A cardiac computed tomography (CT) is more reliable for lead tip identification. Such a case is usually managed by repositioning the leads at the desired position, at the risk of pericardial effusion, infection, and prolonged admission.
    [Show full text]
  • Cardiac Pacemaker
    Thorax: first published as 10.1136/thx.25.3.267 on 1 May 1970. Downloaded from Thorax (1970), 25, 267. Long-term evaluation of the General Electric cardiac pacemaker DONALD R. KAHN, MARVIN M. KIRSH, SATHAPORN VATHAYANON, PARK W. WILLIS, III, JOSEPH A. WALTON, KAREN McINTOSH, PAULINE W. FERGUSON, and HERBERT SLOAN Department of Surgeir and Medicine, University of Michigan Medical Center, Ann Arbor, MI 48104 A review of General Electric (G.E.) electronic cardiac pacemakers for symptomatic complete A-V heart 'block in two sequential three-year periods at the University of Michigan Medical Center indicates that there has been no increase in the useful life of these units. With G.E. epicardiall pacemakers failure occurred after an average of 12 months. In the early years the major cause of failure was wire breakage, and the later major cause was battery exhaustion or component failure. Exit block was a major complication. There was no improvement when G.E. catheter pacemakers were used instead of the epicardial type. The Medtronic catheter pace- makers lasted longer, with fewer battery and component failures and no instances of exit block. Although infection was more common with Medtronic pacemakers, secondary to erosion of the power unit or the catheter through the skin, it may be that this complication could be eliminated by locating the battery box beneath the latissimus dorsi muscle in the axilla and by careful catheter placement to avoid pressure necrosis and subsequent cutaneous perforation. http://thorax.bmj.com/ The treatment of complete atrioventricular heart pacemaker has been improved in design and con- block by the operative implantation of electronic struction enough to improve its function in the cardiac pacemakers has prolonged the life of many clinical setting.
    [Show full text]
  • Mechanisms Underlying the Cardiac Pacemaker: the Role of SK4 Calcium-Activated Potassium Channels
    npg Acta Pharmacologica Sinica (2016) 37: 82–97 © 2016 CPS and SIMM All rights reserved 1671-4083/16 www.nature.com/aps Review Mechanisms underlying the cardiac pacemaker: the role of SK4 calcium-activated potassium channels David WEISBROD, Shiraz Haron KHUN, Hanna BUENO, Asher PERETZ, Bernard ATTALI* Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel The proper expression and function of the cardiac pacemaker is a critical feature of heart physiology. The sinoatrial node (SAN) in human right atrium generates an electrical stimulation approximately 70 times per minute, which propagates from a conductive network to the myocardium leading to chamber contractions during the systoles. Although the SAN and other nodal conductive structures were identified more than a century ago, the mechanisms involved in the generation of cardiac automaticity remain highly debated. In this short review, we survey the current data related to the development of the human cardiac conduction system and the various mechanisms that have been proposed to underlie the pacemaker activity. We also present the human embryonic stem cell- derived cardiomyocyte system, which is used as a model for studying the pacemaker. Finally, we describe our latest characterization of the previously unrecognized role of the SK4 Ca2+-activated K+ channel conductance in pacemaker cells. By exquisitely balancing the inward currents during the diastolic depolarization, the SK4 channels appear to play a crucial role in human cardiac automaticity. Keywords: cardiac pacemaker; sinoatrial node; SK4 K+ channel; Ca2+ clock model; voltage clock model Acta Pharmacologica Sinica (2016) 37: 82−97; doi: 10.1038/aps.2015.135 Introduction studying the pacemaker, and the most recent characterization Normal cardiac function depends on the adequate timing of of the previously unrecognized role of the SK4 Ca2+-activated excitation and contraction in the various regions of the heart K+ channel conductance in pacemaker cells.
    [Show full text]
  • Symbiotic Cardiac Pacemaker
    ARTICLE https://doi.org/10.1038/s41467-019-09851-1 OPEN Symbiotic cardiac pacemaker Han Ouyang 1,2,6, Zhuo Liu1,3,6, Ning Li4,6, Bojing Shi1,3,6, Yang Zou1,2, Feng Xie4,YeMa4, Zhe Li1,2,HuLi1,3, Qiang Zheng 1,2, Xuecheng Qu1,2, Yubo Fan3, Zhong Lin Wang 1,2,5, Hao Zhang1,4 & Zhou Li 1,2 Self-powered implantable medical electronic devices that harvest biomechanical energy from cardiac motion, respiratory movement and blood flow are part of a paradigm shift that is on the horizon. Here, we demonstrate a fully implanted symbiotic pacemaker based on an implantable triboelectric nanogenerator, which achieves energy harvesting and storage as 1234567890():,; well as cardiac pacing on a large-animal scale. The symbiotic pacemaker successfully corrects sinus arrhythmia and prevents deterioration. The open circuit voltage of an implantable triboelectric nanogenerator reaches up to 65.2 V. The energy harvested from each cardiac motion cycle is 0.495 μJ, which is higher than the required endocardial pacing threshold energy (0.377 μJ). Implantable triboelectric nanogenerators for implantable medical devices offer advantages of excellent output performance, high power density, and good durability, and are expected to find application in fields of treatment and diagnosis as in vivo symbiotic bioelectronics. 1 CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Micro-Nano Energy and Sensor, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, 100083 Beijing, China. 2 School of Nanoscience and Technology, University of Chinese Academy of Sciences, 100049 Beijing, China. 3 Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, 100083 Beijing, China.
    [Show full text]
  • Preliminary Quantitative Proteomics Analysis in Chronic and Latent Keshan Disease by Itraq Labeling Approach
    www.impactjournals.com/oncotarget/ Oncotarget, 2017, Vol. 8, (No. 62), pp: 105761-105774 Research Paper Preliminary quantitative proteomics analysis in chronic and latent Keshan disease by iTRAQ labeling approach Yuxiao Sun1,2, Chuanyu Gao1,2, Xianqing Wang1,2 and Yuhao Liu1,2 1Department of Cardiology, Zhengzhou University, People’s Hospital, Zhengzhou, Henan 450003, PR China 2Department of Cardiology, Henan Provincial People’s Hospital, Zhengzhou, Henan 450003, PR China Correspondence to: Chuanyu Gao, email: [email protected] Keywords: Keshan disease; iTRAQ; proteomics; DEPs; biomarker Received: August 12, 2017 Accepted: October 05, 2017 Published: November 11, 2017 Copyright: Sun et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License 3.0 (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. ABSTRACT Keshan disease is a congestive cardiomyopathy. Dietary selenium deficiency combined with additional stressors are recognized to cause the cardiomyopathies. In this study, clinical condition of individuals with different subtypes including chronic and latent were analyzed. ECG abnormalities, chest radiography, echocardiography and blood selenium concentration were assessed. Subsequently, in effort to uncover proteins that were reliably changed in patients, isobaric tags for absolute and relative quantitation technology was applied. Bioinformatics analysis of the differentially expressed proteins were performed by means of Gene Ontology classification, KEGG pathway, and Ingenuity Pathway Analysis. ELISA experiment was used to detect the interesting proteins. As a result, chronic patients showed more EGC abnormalities compared to Latent. All patients had low blood selenium level. Proteomics data revealed 28 differentially expressed proteins.
    [Show full text]