ECG INTERPRETATION: FROM PATHOPHYSIOLOGY TO CLINICAL APPLICATION

ECG INTERPRETATION: FROM PATHOPHYSIOLOGY TO CLINICAL APPLICATION

ECG INTERPRETATION: FROM PATHOPHYSIOLOGY TO CLINICAL APPLICATION by Fred Kusumoto, MD Electrophysiology and Pacing Service Division of Cardiovascular Diseases Department of Medicine Mayo Clinic Jacksonville, Florida, USA 123

Fred Kusumoto, MD Division of Cardiovascular Diseases Department of Medicine Mayo Clinic Jacksonville, Florida, USA Kusumoto.Fred@mayo.edu ISBN 978-0-387-88879-8 e-isbn 978-0-387-88880-4 DOI 10.1007/978-0-387-88880-4 Library of Congress Control Number: 2008937757 c Springer Science+Business Media, LLC 2009 All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer Science+Business Media, LLC, 233 Spring Street, New York, NY 10013, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use in this publication of trade names, trademarks, service marks, and similar terms, even if they are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights. While the advice and information in this book are believed to be true and accurate at the date of going to press, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. Printed on acid-free paper springer.com

To Laura, Miya, Hana, and Aya for their patience and understanding, and to my parents for putting up with a very inquisitive child.

Preface Why write another book on ECG analysis and interpretation? Although there are a number of superb introductory and comprehensive books on ECG interpretation, there are very few books that provide the reader information beyond the basics, other than encyclopedic texts. In addition, ECG reading has been traditionally taught using pattern recognition. However, over the past two decades there has been a tremendous explosion of basic research that has transformed our understanding of the basis of the ECG. Finally, teaching ECGs has often been done by stand-alone lectures that have little clinical context; or worse, no organized teaching of ECGs is available because of the tremendous demands of the increasing depth and breadth of medical knowledge that must be mastered during medical school, training, and beyond to become a consumate clinician. This book has been written to fill these gaps. Although this book provides basic information on ECG analysis it also attempts to explain the electrophysiologic underpinnings for the ECG. Traditional findings such as ST segment elevation are explained with a framing case for each chapter with a series of clinically based questions at the end designed to help the student understand the importance of the ECG in clinical medicine. Finally, the book ends with a discussion and series of clinical problems that will help the reader develop a personal style for ECG analysis. In the end I hope the reader finds this text useful for learning how to interpret ECGs in the context of patient care. This book grew out of a series of lectures on ECG analysis I have given at the University of California, San Francisco; the University of New Mexico; and the Mayo Clinic, Jacksonville. I would like to thank the many students, residents, and colleagues that contributed to this project. I would also like to thank my three mentors that taught me ECG analysis over the years: Nora Goldschlager, Mel Scheinman, and Tom Evans. I appreciate the patience of Melissa Ramondetta for letting this project evolve over a very long time. Finally I would like to thank my family for putting up with the constant typing and the missed soccer games and school plays that a task like this inevitably requires. vii

Table of contents Part I: Basic electrophysiology and electrocardiography... 1 1. Cardiac anatomy and electrophysiology.... 3 2. Physics of electrocardiography.... 11 3. The normal electrocardiogram.... 21 Part II: Abnormal depolarization... 35 4. Chamberenlargement... 37 5. Conduction abnormalities in the His-Purkinje tissue... 49 Part III: Abnormal repolarization... 63 6. Ventricular repolarization: T waves and U waves...... 65 7. ST segment elevation and other ECG findings in myocardial infarction.... 81 8. ST segment elevation not associated with myocardial infarction......111 Part IV: Arrhythmias...127 9. Premature beats...129 10. Bradycardia.... 139 11. Supraventricular tachycardia....... 155 12. Wide complex tachycardia....183 13. Pacemakers... 205 ix

x Table of contents Part V: Putting it all together... 215 14. Analyzing ECGs: Methods, techniques, and identifying abnormalities....217 15. Analyzing ECGs: Putting it together with case studies...225 16.Electrolytedisorders... 249 17. Orphans....259 Appendix....277 Extra practice So you re a glutton for punishment....283 Index... 293