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(BQ) Part 1 book Electrocardiography of arrhythmias - A comprehensive review presents the following contents: Important concepts, sinus node dysfunction, atrioventricular conduction abnormalities, junctional rhythm, atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardias.
•c v e expeFtcons It.com Searchable Full Text Online ELECTROCARDIOGRAPHY OF ARRHYTHMIAS: A Comprehensive Review A Companion to CARDIAC ELECTROPHYSIOLOGY: From Cell to Bedside ELECTROCARDIOGRAPHY OF ARRHYTHMIAS: A Comprehensive Review A Companion to CARDIAC ELECTROPHYSIOLOGY: From Cell to Bedside MITHILESH K DAS, MD Associate Professor of Clinical Medicine Krannert Institute of Cardiology Indiana University School of Medicine Chief, Cardiac Arrhythmia Service Roudebush Veterans Affairs Medical Center Indianapolis, Indiana DOUGLAS P ZIPES, MD Distinguished Professor Professor Emeritus of Medicine, Pharmacology, and Toxicology Director Emeritus, Division of Cardiology and the Krannert Institute of Cardiology Indiana University School of Medicine Editor, HeartRhythm Indianapolis, Indiana Saunders An Imprint of Elsevier 1600 John F Kennedy Blvd Ste 1800 Philadelphia, PA 19103-2899 ELECTROCARDIOGRAPHY OF ARRHYTHMIAS: A COMPREHENSIVE REVIEW ISBN: 978-1-4377-2029-7 Copyright © 2012 by Saunders, an imprint of Elsevier Inc All rights reserved No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher Notices Knowledge and best practice in this field are constantly changing As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility With respect to any drug or pharmaceutical products identified, readers are advised to check the most current information provided (i) on procedures featured or (ii) by the manufacturer of each product to be administered, to verify the recommended dose or formula, the method and duration of administration, and contraindications It is the responsibility of practitioners, relying on their own experience and knowledge of their patients, to make diagnoses, to determine dosages and the best treatment for each individual patient, and to take all appropriate safety precautions To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein Library of Congress Cataloging-in-Publication Data Das, Mithilesh K Electrocardiography of arrhythmias : a comprehensive review / Mithilesh K Das, Douglas P Zipes – 1st ed p ; cm Includes bibliographical references and index ISBN 978-1-4377-2029-7 (pbk : alk paper) I. Zipes, Douglas P. II. Title [DNLM: 1. Arrhythmias, Cardiac–diagnosis. 2. Electrocardiography WG 330] 616.1′207547–dc23 2011053492 Executive Content Strategist: Dolores Meloni Content Development Specialist: Taylor Ball Publishing Services Manager: Anne Altepeter Project Manager: Louise King Design Manager: Louis Forgione Working together to grow libraries in developing countries Printed in China Last digit is the print number: 9 8 7 6 5 4 3 2 www.elsevier.com | www.bookaid.org | www.sabre.org To our wives and families, without whose support we could not have accomplished a fraction of what we have achieved To my parents, Ganpati Lal Das and Bimla Das; my wife, Rekha; and my children, Awaneesh and Mohineesh —MKD To my wife, Joan, and my children, Debra, Jeffrey, and David —DPZ PREFACE Many books, both clinical and basic, have been written about the field of cardiac electrophysiology Similarly, a multitude of texts have been published on the interpretation of the clinical electrocardiogram (ECG) In this text we have combined the two skill sets: the content is electrocardiography of arrhythmias, but we have approached the topic from an understanding of both clinical and basic electrophysiology As a result, this book should be useful to a broad spectrum of physicians, from internists with an interest in cardiology and trainees in cardiology and electrophysiology to experienced cardiologists This book is also the first companion to the well-known text, Cardiac Electrophysiology: From Cell to Bedside, now in its fifth edition We hope you find it a useful addition to help with your ECG reading skills We wish to thank John C Bailey, MD, who provided several key electrocardiographic images used in this book MITHILESH K DAS DOUGLAS P ZIPES vii ELECTROCARDIOGRAPHY OF ARRHYTHMIAS A Comprehensive Review By Mithilesh K Das and Douglas P Zipes CHAPTER 1 IMPORTANT CONCEPTS CHAPTER 2 SINUS NODE DYSFUNCTION CHAPTER 3 ATRIOVENTRICULAR CONDUCTION ABNORMALITIES CHAPTER 4 JUNCTIONAL RHYTHM CHAPTER 5 ATRIOVENTRICULAR NODAL REENTRANT TACHYCARDIA CHAPTER 6 ATRIOVENTRICULAR REENTRANT TACHYCARDIAS CHAPTER 7 ATRIAL TACHYCARDIA CHAPTER 8 ATRIAL FLUTTER CHAPTER 9 ATRIAL FIBRILLATION CHAPTER 10 WIDE COMPLEX TACHYCARDIA CHAPTER 11 VENTRICULAR TACHYCARDIA IN STRUCTURAL HEART DISEASE CHAPTER 12 VENTRICULAR TACHYCARDIA IN THE ABSENCE OF STRUCTURAL HEART DISEASE CHAPTER 13 POLYMORPHIC VENTRICULAR TACHYCARDIA AND VENTRICULAR FIBRILLATION IN THE ABSENCE OF STRUCTURAL HEART DISEASE ix 1 IMPORTANT CONCEPTS A normal 12-lead electrocardiogram (ECG) includes P, QRS, T, and sometimes the U waves (Figure 1-1) The P wave is generated by activation of the atria, the P-R segment represents the duration of atrioventricular (AV) conduction, the QRS complex is produced by the activation of the two ventricles, and the ST-T wave reflects ventricular recovery Normal values for the various intervals and waveforms of the ECG are shown in Table 1-1 The range of normal values of these measurements reflects the sub stantial interindividual variability related to (among other factors) differences in age, gender, body habitus, heart orientation, and physiology In addition, significant differences in electrocardiographic patterns can occur in an individual’s ECGs recorded days, hours, or even minutes apart These intraindividual variations may be caused by technical issues (e.g., changes in electrode position) or the biologic effects of changes in posture, temperature, autonomics, or eating habits and may be sufficiently large to alter diagnostic evidence for conditions such as chamber hypertrophy P WAVE Normal P waves (duration = 0.06 mm-sec Increased duration and depth of terminal-negative portion of P wave in lead V1 (P terminal force) so that area subtended by >0.04 mm-sec Rightward shift of mean P wave axis to more than +75° Leftward shift of mean P wave axis to between −30° and −45° through the ventricular wall to the epicardial surface The normal Q wave is the first negative deflection of the QRS, which is not preceded by any R wave and represents interventricular depolarization The R wave is the first positive deflection in the QRS complex Subsequent positive deflection in the QRS above the baseline represents a bundle branch delay or block (BBB) called R′ (R prime) The S wave is the first negative deflection (below the baseline) after an R wave The QS wave is a QRS complex that is entirely a negative wave without any positive deflection (R wave) above the baseline The larger waves that form a major deflection in QRS complexes are usually identified by uppercase letters (QS, R, S), whereas smaller waves with amplitude less than the half of the major positive (R wave) or negative (S wave) deflection are denoted by lowercase letters (q, r, s) Therefore notches in R, S, or QS waves can be defined as qR, Rs, RSR, QrS, or rS patterns The QRS morphology on a particular ECG lead depends on the sum vector of depolarization toward or away from that lead Usually, the R waves are upright in limb leads and augmented limb leads except for lead aVR A QS pattern in lead V1-V2 may represent normal myocardial depolarization, but a Q wave in lead V3 represents myocardial scarring, usually caused by a septal myocardial infarction QRS transition is seen in lead V3-V4 with R wave amplitude larger than S wave amplitude R waves are upright in lead V5-V6 because of a positive net vector toward these precordial leads Poor progression of R wave amplitude across the precordial leads represents severe myocardial disease It is seen in severe nonischemic and ischemic cardiomyopathy with severely reduced left ventricular ejection fraction Q WAVES The normal Q wave duration is 40 ms may be due to scarring from a myocardial infarction Noninfarction Q waves (pseudoinfarction pattern) are also encountered in ventricular hypertrophy, fascicular blocks, preexcitation, cardiomyopathy, pneumothorax, pulmonary embolus, amyloid heart disease, primary and metastatic tumors of the heart, traumatic heart disease, intracranial hemorrhage, hyperkalemia, pericarditis, early repolarization, and cardiac sarcoidosis INTRAVENTRICULAR CONDUCTION ABNORMALITIES QRS prolongation can be due to the conduction system abnormality resulting from a right bundle branch block (RBBB) or a left bundle branch block (LBBB) When the QRS duration is prolonged, often called wide (>120 ms), and its morphology does not qualify for a BBB, then it is called an interventricular conduction defect (IVCD) IVCD can result from myocardial disease such as coronary artery disease or cardiomyopathy IVCD can also result from electrolyte abnormalities such as hypokalemia or antiarrhy thmic drug therapy, mainly with the use of class I drugs (sodium channel blockers), which prolong the conduction velocity of the myocardial depolarizing waves (Figure 1-10) IVCD can represent a substrate for ventricular arrhythmias Other causes of a wide QRS include premature ventricular complexes, ventricular preexcitation, or a paced ventricular rhythm FRAGMENTED QRS COMPLEXES Fragmented QRS (fQRS) is defined as the presence of one or more notches in the R wave or S wave without any BBB in two contiguous leads Fragmented wide QRS (f-WQRS) is defined as QRS duration >120 ms with >2 notches in the R wave or the S wave in two contiguous leads QRS fragmentation and Q waves represent myocardial infarction ... wandering atrial pacemakers (Figure 1- 4 ) Frequent premature atrial complexes can provoke atrial tachyarrhythmia (atrial tachycardia, atrial fibrillation, and atrial flutter) Paroxysmal atrial fibrillation... Reentrant Tachycardias Atypical and Rare Accessory Pathway Location Atriofasciular Atrioventricular Nodoventricular Atriohisian Nodofascicular Fasciculoventricular FIGURE 6-2 8 ▶ Atypical accessory... lead V1 and negative delta wave in lead III and aVF AP was mapped at the posteroseptal mitral annulus 17 3 17 4 CHAPTER 6 Atrioventricular Reentrant Tachycardias FIGURE 6-2 1? ?? ▶ Electrocardiogram