TEXTBOOK OF CLINICAL ELECTROCARDIOGRAPHY TEXTBOOK OF CLINICAL ELECTROCARDIOGRAPHY by A. BAYES DE LUNA Professor of Cardiology, Faculty of Medicine, University Autonoma of Barcelona, and Head of Electrocardiology, Cardiology Department, Hospital San Pablo, Barcelona, Spain 1987 MARTIN US NIJHOFF PUBLISHERS ~. a member of the KLUWER ACADEMIC PUBLISHERS GROUP ., DORDRECHT I BOSTON I LANCASTER • Distributors for the United States and Canada: K1uwer Academic Publishers, P.O. Box 358, Accord Station, Hingham, MA 02018-0358, USA for the UK and Ireland: Kluwer Academic Publishers, MTP Press Limited, Falcon House, Queen Square, Lancaster LAIIRN, UK for all other countries: Kluwer Academic Publishers Group, Distribution Center, P.O. Box 322, 3300 AH Dordrecht, The Netherlands Library of Congress Cataloging in Publication Data Bayes de Luna, Antonio. Textbook of clinical electrocardiography. Includes bibliographies and index. 1. Electrocardiography. 2. Heart - Diseases - Diagnosis. I. Title. [DNLM: 1. Electrocardiography. WG 140 B357tJ RC683.5.E5B326 1987 616.1'207'547 86-17956 ISBN-13: 978-0-89838-835-0 e-ISBN-13: 978-94-009-4299-8 001: 10.1007/978-94-009-4299-8 Copyright © 1987 by Martinus Nijhoff Publishers, Dordrecht. Softcover reprint of the hardcover 1st edition 1987 All rights reserved. No part of this publication may be re produced, stored in a retrieval system, or transmitted in any form or by any means, mechanical, photocopying, recording, or otherwise, without the prior written permission of the pub lishers. Martinus Nijhoff Publishers, P.O. Box 163, 3300 AD Dordrecht, The Netherlands. Table of contents Prologue by H.J.J. Wellens XIX Preface XXI Introduction XXV 1 Cardiac electrophysiology 1 1.1 Heart cells 1 1.1.1 Types 1 1.1.2 Properties 2 1.2 Cellular activation 2 1.2.1 Diastolic polarization phase 2 1.2.2 Systolic cellular depolarization phase 6 1.2.3 Systolic cellular repolarization phase 8 1.2.4 TAP morphology in different heart structures 9 1.3 Cell electrogram 9 1.4 Concept of dipole 10 1.4.1 Depolarization dipole 11 1.4.2 Repolarization dipole 11 1.4.3 Depolarization and repolarization dipole in an ischemic cell 12 1.5 Concept of hemifield 12 1.6 Cardiac activation 14 1.6.1 Atrial activation: P loop 14 1.6.1.1 Atrial depolarization: P loop 15 1.6.1.2 Atrial repolarization 16 1.6.2 Ventricular activation: QRS and T loops 17 1.6.2.1 Ventricular depolarization: QRS loop 18 1.6.2.2 Ventricular repolarization: T loop 23 1.6.3 The domino theory 25 1.7 Correlation between the TAP curve and ECG curve 27 2 The normal electrocardiogram 2.1 Wave nomenclature 30 2.2 Inscription system 30 VI 2.3 Leads 32 2.3.1 Frontal plane leads 33 2.3.1.1 Bipolar limb leads: triaxial system of Bailey 33 2.3.1.2 Unipolar limb leads: hexaxial system of Bailey 36 2.3.2 Horizontal plane leads 37 2.4 Hemifields 38 2.4.1 Positive and negative hemifields of the frontal and horizontal plane leads 38 2.4.2 Loop-electrocardiographic morphology correlation 38 2.5 Interpretation routine 41 2.5.1 Heart rate 41 2.5.2 Rhythm 41 2.5.3 PR interval and segment 43 2.5.4 QT interval 43 2.5.5 Calculation of the electrical axis of the heart 47 2.5.5.1 Indeterminate electrical axis 51 2.5.6 The normal P wave 53 2.5.6.1 Axis in the frontal plane (Ap) 54 2.5.6.2 Polarity and morphology 54 1 Polarity 54 2 Morphology 55 2.5.6.3 Duration and voltage 56 2.5.7 The normal QRS complex 56 2.5.7.1 Axis on the frontal plane (AQRS) 58 2.5.7.2 Polarity and morphology: modifications with different rotations 58 1 Heart rotations 58 La Rotation on the anteroposterior axis 58 1.b Rotation on the longitudinal axis 61 1.c Rotation on the transversal axis 62 1.d Combined rotations 63 2 Normal notches and slurrings 66 3 Normal 'Q' wave 67 2.5.7.3 QRS duration and voltage 68 2.5.8 ST segment and T wave 69 2.5.8.1 ST segment 71 2.5.8.2 T wave 73 1 Axis on the frontal plane (AT) 73 2 Normal polarity and morphology 73 3 Voltage 74 2.5.9 U wave 75 2.6 Electrocardiographic variations with age 75 2.6.1 Infants, children and adolescents 75 2.6.2 Elderly people 76 2.7 Other normal variants 77 2.7.1 P wave and atrial repolarization wave (ST-Ta) 77 2.7.2 Ventricular depolarization 77 2.7.2.1 Hyperdeviation of AQRS in the frontal plane 77 2.7.2.2 Morphology of first degree right or left ventricular block 79 VII 1 Morphology with r' in VI with QRS <0.12sec 79 2 Morphology of first degree left ventricular block 80 2.7.3 Repolarization alterations 80 2.7.4 Arrhythmias 82 2.8 Sensitivity and specificity of the ECG 82 3 Other electrocardiological techniques 3.1 Vectorcardiography: x,y,z leads 86 3.1.1 Methodology 86 3.1.2 Clinical utility of vectorcardiography and the orthogonal leads 88 3.2 Exercise ECG test 90 3.2.1 Methodology 90 3.2.2 Utility 92 3.2.3 Interpretation 93 3.2.3.1 Physiologic responses to exercise 93 3.2.3.2 Abnormal responses to exercise 93 1 Alterations of the ST segment 93 La Normal basal ECG 94 1.b Altered basal ECG 98 2 Other repolarization alterations 98 3 Increase in R wave voltage 98 4 Appearance of ventricular block 98 5 Arrhythmias 98 3.2.4 Comparison with other tests 99 3.2.5 Limitations 99 3.3 Holter ECG and allied techniques 99 3.3.1 Methodology 100 3.3.2 Utility 104 3.3.2.1 Arrhythmias 104 1 Evaluation of the electrophysiologic mechanism of the arrhythmias 104 2 Arrhythmia-symptom correlation 104 3 Investigation of the prevalence of arrhythmias 104 4 Frequency and duration of supraventricular or ventricular tachycardia crises 104 5 Noninvasive evaluation of antiarrhythmic therapy 104 6 Control of pacemaker function 104 7 Patients with syncope or near-syncope 106 3.3.2.2 Repolarization alterations 106 1 Repolarization alterations other than in coronary heart disease 106 2 Repolarization alterations due to coronary heart disease 106 2.a Secondary versus primary angina 106 2.b Sensitivity and specificity of the Holter ECG for the diagnosis of coronary disease 108 2.c Control of antianginal treatment 109 3.3.3 Limitations 109 3.3.4 Allied techniques 109 3.3.4.1 Alteration analyzer 109 VIII 3.3.4.2 Transtelephonic ECG: SAMTI system 110 3.4 Intracavitary electrocardiography 110 3.4.1 Methodology 111 3.4.2 Utility 113 3.4.2. 1 To measure functional and effective refractory period 113 3.4.2. 2 Topographic localization of A V block 113 1 Suprahisian A V blocks 113 La Intraatrial block 113 1.b Intranodal block 114 2 Intrahisian blocks 114 3 Infrahisian blocks 114 3.4.2. 3 Study of the characteristics of A V conduction 114 3.4.2. 4 Study of the sinus function 115 3.4.2. 5 Study of the characteristics of the accessory bundles 116 3.4.2. 6 Study of the characteristics of a tachycardia 117 3.4.2. 7 Topographic localization of right ventricular block 118 3.4.2. 8 Pharmaco-electrophysiology 118 3.4.2. 9 Other therapeutic uses 119 3.4.2.10 Differentiating patients with high risk of sudden death (SD) 119 3.4.2.11 Enhancing the diagnostic precision of the conventional ECG 119 3.4.2.12 When intracavitary electrophysiologic study should be realized 119 3.4.3 Limitations 120 3.5 Unified ECG interpretation 120 3.5.1 Minnesota Code 120 3.5.2 Interpretation by computer 120 3.6 Other electrocardiologic techniques 123 3.6.1 Spatial velocity technique 123 3.6.2 Cardiac mapping 123 3.6.3 External techniques to record late potentials 124 3.6.4 Other techniques 124 4 Alterations in the atrial electrocardiogram 4.1 Alterations in the P wave 130 4.1.1 Atrial enlargement 130 4.1.1.1 Right atrial enlargement (RAE) (dilation) 130 1 Changes in the P wave 130 2 Changes in the QRS complex 133 3 Diagnostic criteria: ECG and VCG 135 4.1.1.2 Left atrial enlargement (LAE) (dilation) 135 1 Changes in the P wave 135 2 Diagnostic criteria: ECG and VCG 137 4.1.1.3 Biatrial enlargement 138 1 Electrocardiogram 138 2 Vectorcardiogram 138 4.1.2 Atrial block 138 4.1.2.1 Sinoatrial block 139 4.1.2.2 Interatrial block 139 IX 4.1.2.3 Intraatrial block 140 4.2 Alterations in atrial repolarization 143 4.2.1 Depressed ST-Ta 143 4.2.2 Elevated ST- Ta 143 5 Ventricular enlargement 5.1 Preliminary considerations: definition of terms 145 5.2 Left ventricular enlargement (LVE) 146 5.2.1 Left ventricular hypertrophy (L VH) 146 5.2.1.1 Electrocardiographic alterations 147 1 Changes in the QRS complex 147 2 Changes in ST segment and T wave 150 5.2.1.2 Diagnostic ECG criteria 153 1 Limitations of the diagnostic criteria 155 La Methodological considerations 155 I.b Limitations conditioned by constitutional factors 155 5.2.1.3 Diagnostic VCG criteria 157 5.2.1.4 Value of the echocardiogram in the diagnosis of left ventricular enlargement (L VE) 157 5.2.1.5 Value of other electrocardiologic techniques 159 5.2.1.6 Special characteristics of some types of left ventricular enlargement (LVE) 159 1 L VE in children 159 2 Left ventricular dilation associated with L VH 159 3 Indirect signs of L VE 159 5.2.1.7 Differential diagnosis 160 1 Left ventricular enlargement versus left ventricular block 160 2 WPW preexcitation Type 1 160 3 Ischemic heart disease 161 3.a Lateral ischemia vs. left ventricular enlargement 161 3.b QS morphology in right precordial leads in patients with L VE 161 5.2.1.8 Final considerations 161 5.3 Right ventricular enlargement (RVE) 161 5.3.1 Right ventricular hypertrophy (R VH) 162 5.3.1.1 Electrocardiographic alterations 164 1 Electrocardiographic changes due to progressively anterior and right QRS loop situation 164 2 Electrocardiographic changes due to progressively posterior and right QRS loop 168 5.3.1.2 Electrocardiographic diagnostic criteria 168 5.3.1.3 Vectorcardiographic diagnostic criteria 170 5.3.1.4 Value of other techniques for the diagnosis of right ventricular enlargement 171 5.3.1.5 Special characteristics of some types of right ventricular enlargement 172 1 Right ventricular dilation 172 2 R VE in children 174 3 Indirect signs of R VE 174 5.3.1.6 Differential diagnosis 174 1 Differential diagnosis of RVH with dominant R morphology in VI 174 2 Differential diagnosis of RVH with rS pr QS morphology in VI 176 X 5.4 Biventricular enlargement 177 5.5 Enlargement of the four cavities 180 6 Ventricular block 6.1 Concept of heart block 183 6.2 Ventricular block 183 6.2.1 Definition of terms 183 6.2.2 General considerations 184 6.2.3 Global right ventricular block (GRVB) 187 6.2.3.1 Third degree (advanced) block 187 1 Activation 187 2 ECG-VCG diagnosis 189 2.a QRS duration 189 2.b AQRS in the fontal plane 190 2.c ECG-VCG morphologies: Diagnostic criteria 191 3 Intracavitary ECG 193 4 Association with ventricular enlargement 194 5 Association with myocardial infarction 194 6 Clinical implications 194 6.2.3.2 Second degree block 196 6.2.3.3 First degree (not advanced) block 196 6.2.3.4 Dominant R morphology in VI not due to RVB 199 6.2.4 Zonal or divisional right ventricular blocks 200 6.2.5 Global left ventricular block (GLVB) 202 6.2.5.1 Third degree (advanced) block 202 1 Activation 202 2 ECG-VCG. diagnosis 205 2.a QRS duration 205 2.b AQRS in the frontal plane 205 2.c ECG-VCG morphologies: Diagnostic criteria 206 3 Intracavitary ECG 209 4 Association with ventricular enlargement 210 5 Association with myocardial infarction 210 6 Clinical implications 210 6.2.5.2 Second degree block 210 6.2.5.3 First degree (not advanced) block 211 6.2.5.4 Other causes of GLV B-like morphology 212 6.2.6 Left zonal (or divisional) block 212 6.2.6.1 Superoanterior hemiblock (SAH) 214 1 Activation 214 2 ECG-VCG diagnosis 214 2.a QRS duration 214 2.b AQRS in the frontal plane 214 2.c ECG-VCG morphologies: Diagnostic criteria 216 3 Differential diagnosis 217 4 Special characteristics 218 5 Clinical implications 218 Xl 6.2.6.2 Inferoposterior hemiblock (IPH) 219 1 Activation 219 2 ECG-VCG diagnosis 220 2.a QRS duration 220 2.b AQRS in the frontal plane 220 2.c ECG-VCG morphologies: Diagnostic criteria 221 3 Differential diagnosis 221 4 Special characteristics 221 5 Clinical implications 221 6.2.7 Anteroseptal medial fiber block 222 6.2.8 Combined blocks 223 6.2.8.1 Bifascicular blocks 223 1 Global right ventricular block + global left ventricular block (bitruncal block) 223 2 Superoanterior hemiblock with inferoposterior hemiblock 225 3 Global left ventricular block (trunk block)with superoanterior or infero- posterior hemiblock 225 4 Alternating block of two of the four fascicles 225 5 Global advanced right ventricular block (GARVB) with advanced supero- anterior hemiblock (SAH) 225 5.a Activation 225 5.b ECG-VCG diagnosis 225 5.c Masked blocks 226 6 Global advanced right ventricular block (GARVB) with advanced infero- posterior hemiblock (IPH) 227 6.a Activation 227 6.b ECG-VCG diagnosis 228 7 Clinical implications of the bifascicular block 228 6.2.8.2 Trifascicular block 230 7 Preexcitation 7.1 Definition of the term 234 7.2 Interest of the diagnosis 234 7.3 Types of preexcitation 234 7.4 Classic WPW type preexcitation 235 7.4.1 Accessory connections 236 7.4.1.1 Anatomic characteristics 236 7.4.1.2 Electrophysiologic characteristics 236 7.4.2 Electrocardiologic diagnosis 240 7.4.2.1 Alterations in the atriogram 240 7.4.2.2 PR interval 240 7.4.2.3 Alterations in the ventriculogram 240 1 Morphology of the QRS complex and loop 242 2 Localization of the accessory bundle by surface ECG 245 3 Repolarization alterations 245 7.4.3 Electrophysiologic techniques for differentiating types of preexcitation 248 7.4.4 Differential diagnosis of classic WPW type preexcitation 249