12-Lead ECG: The Art Of Interpretation

2013·34.87 MB·English

by  Tomas B. Garcia

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Library of Congress Cataloging-in-Publication Data
Garcia, Tomas B., 1952- author.
12-lead ECG: the art of interpretation / Tomas Garcia. – Second edition.
p. ; cm.
Twelve lead electrocardiography
Includes index.
ISBN-13: 978-0-7637-7351-9 (pbk.)
ISBN-10: 0-7637-7351-4 (pbk.)
Title. II. Title: Twelve lead electrocardiography.
[DNLM: 1. Electrocardiography—Programmed Instruction. WG 18.2]
RC683.5.E5
616.1′207547—dc23 2013029723
6048
Printed in the United States of America
17 16 15 14 13 10 9 8 7 6 5 4 3 2 1
Welcome
12-Lead ECG: The Art of Interpretation
Welcome to the comprehensive resource on 12-lead ECG! This all-encompassing text is
designed to bring you from having little or no electrocardiographic knowledge to the
level of a fully advanced interpreter of ECGs. Whether you are a paramedic, nurse,
nurse practitioner, physician assistant, medical student, or physician wanting to learn or
brush up on your knowledge of electrocardiography, this book will meet your needs.
This text contains over 250 full-size, real-life ECGs. Each chapter introduces
background information that is followed by ECG strips, analyses, and interpretations.
The final chapter allows you to put together everything you have learned, and a new
final section provides 50 full-size, real-life 12-lead ECGs with which to practice your
interpretation skills.
Unlike other texts, this book is set up to be accessed by three different levels of
readers:
• Level 1, indicated in blue, provides basic information for the beginning student
who has minimal experience interpreting ECGs. This level addresses basic
information that you will need to understand ECGs. They are the foundation
concepts upon which we will build.
• Level 2, indicated in green, provides intermediate information applicable to
those with a basic understanding of the principles of electrocardiography, but
who want to solidify and begin to expand that knowledge. If you have
completed Level 1 of this book or have read some basic books on rhythms or
12-leads, then you are probably at this level. If you are already at this level, you
can skip Part 1 and start at Part 2.
• Level 3, indicated in red, provides advanced information. This is a level for
those who have some mastery of electrocardiography, such as advanced
practitioners. This level requires a solid understanding of the ECG and the
disease complexes that can cause the changes shown on the ECG.
12-Lead ECG: The Art of Interpretation is designed to grow with you as your
knowledge of electrocardiography progresses. Your journey into electrocardiography
begins when you establish your level (see How to Pick Your Starting Level, on p. 2 at
the beginning of Part 1). As a Level 1 or Level 2 student, read the text that pertains only
to your level. Once you have mastered this material, return to the beginning of the book
and read the text in the next level. You always have the previous levels’ information
available for reference, only a few pages away. The entire text, regardless of the level, is
written in a friendly, easy-to-read tone that is clear and understandable, maximizing
your comfort.
Read on to learn how to pick your starting level and to begin learning how to read
an ECG. Before long, you will become an advanced ECG interpreter and better
equipped to save lives.
How to Use This Book
General Overview
Most electrocardiography textbooks were created for either beginners or advanced
students, but leave the intermediate student, or person with some knowledge of 12-lead
and arrhythmia recognition, out of the picture. This text was written for beginner,
intermediate, and advanced students alike.
The format allows you to move at your own speed by providing information in bite-
sized chunks. It is written in an easy-to-read, friendly tone so that you can feel
comfortable while you are reading. There is plenty humor throughout, because life is
short and you have to have fun. We hope this approach enhances your reading
experience and facilitates learning.
The book is broken down into three parts:
• Part 1 presents basic information about the complexes, waves, and intervals, as
well as the ECG and calibration. You will learn about the basic beat or complex
and review the basic anatomy of the heart and the electrical conduction system.
You will also learn how to use some tools that can be very helpful in interpreting
the ECG.
• Part 2 focuses on each wave and interval of the complex, the axis, and the 12-
lead presentation of some rhythm disturbances. This book is not intended to
cover all of the rhythms and you are referred to the reference section for some
suggested reading on this material. Part 2 will cover the electrocardiographic
criteria for the various types of acute myocardial infarctions and provides
examples of each. Finally, Part 2 includes a chapter on putting it all together.
This extremely useful chapter synthesizes all of the information you have
learned to this point. You should plan on spending some time in this chapter and
understanding the concepts thoroughly before you move on.
• Part 3, new to the second edition, includes 50 additional, unique 12-lead ECGs
for practicing your interpretation skills. Included after these ECGs are
discussions and analyses on each of them.
The book has been created to be continuously useful during your development and
is intended to be read and reread as you advance in your knowledge and comfort level
with the material. By rereading the material at increasingly advanced levels, you will
get more out of the material and retain it with greater use.
How to Pick Your Starting Level
The first and most important thing you need to do as you begin the process of using this
book is to establish your level of understanding. There are three levels of understanding
represented by Levels 1, 2, and 3.
Level 1: As a beginner, start in Chapter 1 by reading the Level 1 material. When
you get to Part 2, continue reading the Level 1 material and then look at the ECG
examples to see if you can pick up the information that relates to what you have just
read. Look only at the information on the ECG that pertains to the Level 1 material. Do
not focus on interpretation at this time; that will come later. You can look at the rest of
the waves and complexes, but only concentrate on learning the small amount of
information for that section. Afterward, move on to the next section or chapter. When
you have finished all of the book’s Level 1 material and analyzed all of the ECGs for
that pertinent information, restart the book in Part 2 using the Level 2 material.
Level 2: As an intermediate reader, you can either start with a review of the Level 1
material to refresh yourself, and then move on to Level 2, or simply start with the Level
2 material. Use the Quick Review questions to test your knowledge of the basic
concepts. If you get them wrong, go back to the corresponding Level 1 material and
review it. When you get to the ECGs, try to evaluate them without reading the
corresponding text. Once you have done this, read the text that corresponds with each
ECG and see if you had the concepts right. When you are done with all of the Level 2
material, go back and reread the book using the Level 3 material. To prevent gaps in
knowledge, do not try to read the Level 3 text until you have completed Level 2.
Level 3: The Level 3 material is advanced. This information can be quite complex,
but if you have finished all of the Level 2 material, you should be ready for this level.
Review the sections you do not understand and use other reference books to supplement
your knowledge at this level. Do not think that you need to have mastered the
information upon completion of this book; it takes quite a few years and quite a few
thousand ECGs to truly become a master.
Ready to start? If you are a beginner, start with Chapter 1. If you are unsure of your
level, try going back to Chapter 9 or 10 and see if you understand the material in Level
2. If you feel it is too elementary, then move up. If you feel it is too advanced, move
back. Be truthful with yourself or you will become frustrated. Remember—use this
book until you have gotten everything out of it that you can.
Contents
PART 1: THE BASICS
How to Read an ECG
Chapter 1: Anatomy
Gross Anatomy
Anterior View
The Heart in Cross Section
The Heart as a Pump
Pump Function Simplified
The Electrical Conduction System
Pacemaker Function
Pacemaker Settings
The Sinoatrial (SA) Node
The Internodal Pathways
The Atrioventricular (AV) Node
The Bundle of His
The Left Bundle Branch (LBB)
The Right Bundle Branch (RBB)
The Left Anterior Fascicle (LAF)
The Left Posterior Fascicle (LPF)
The Purkinje System
Chapter In Review
Chapter 2: Electrophysiology
Mechanics of Contraction
Ion Movement and Polarity
Membrane Channels and Action Potential Phases
Chapter In Review
Chapter 3: Individual Vectors
Adding and Subtracting Vectors
The Electrical Axis of the Heart
Electrodes and Waves
Leads Are Like Pictures of the Heart
Lead Placement (Where to Put the “Cameras”)
How the Machine Manipulates the Leads
The Two Lead Systems
The Hexaxial System
The Precordial System
The Heart in Three Dimensions
Localizing an Area: Inferior Wall
Localizing Other Areas
Chapter In Review
Chapter 4: The Actual ECG: Paper and Ink
Boxes and Sizes
Calibration
Where Is Each Lead Represented?
Temporal Relationship of the ECG
Why Is Temporal Spacing Important?
Chapter In Review
Chapter 5: ECG Tools
Calipers: The ECG Interpreter’s Best Friend
How to Use Your Calipers
Comparing Wave Heights
Adding Wave Heights
Comparing Widths
Axis-Wheel Ruler
ECG Rulers
Straight Edge
Chapter 6: The Basic Beat
Introduction to Basic Components
Wave Nomenclature
Individual Components of the ECG Complex
The P Wave
The Tp Wave
The PR Segment
The PR Interval
The QRS Complex
The ST Segment
The T Wave