Contents
© 2008 Amal Mattu & William Brady
Published by Blackwell Publishing
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First published 2008 1 2008
Library of Congress Cataloging-in-Publication Data Mattu, Amal.
ECGs for the emergency physician 2 /Amal Mattu, William Brady, p. ; cm.
“BMJ Books.”
Includes index.
ISBN 978-1-4051-5701-8 (pbk. : alk. paper) 1. Electrocardiography. 2. Emergency physicians. I. Brady, William, 1960- II. Title.
[DNLM: 1. Electrocardiography—methods. 2. Emergency Medical Services. 3. Heart Diseases—diagnosis. WG 140 M444e 2007]
RC683.5.E5M344 2007
616.1’207547—dc22
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Foreword
Do you remember that patient you sent home? It is said that nothing good ever follows that question. One of the most dreaded scenarios is the case where an ECG was misinterpreted, or where the diagnosis, now evident on the ECG, was missed, and the patient was inadvertently (and inappropriately), sent home. How has the ECG become so important to the practice of medicine in the emergency department?
An electrocardiogram (ECG or EKG, abbreviated from the German Elektrokardiogramm) is a graphic produced by an electrocardiograph, which records the electrical activity of the heart over time. In 1902, Willem Einthoven, working in Leiden, The Netherlands, used a galvanometer to record the electrical activity of the heart over time.1 Einthoven assigned the letters P, Q, R, S and T to the various deflections, and described the electrocardiographic findings for a number of disease states. In 1924, he was awarded the Nobel Prize in Medicine for his discovery.2
The ECG has become a fundamental adjunct to the physical exam, owing to its utility in the diagnosis of cardiac arrhythmias, acute myocardial infarction (MI), electrolyte imbalances such as hyperkalemia and hypokalemia, conduction abnormalities, ischemic heart disease and select non-cardiac diseases such as pulmonary embolism, hyperthyroidism and hypothermia.3–5 While not considered a modern discovery, understanding of the clinical correlation of the ECG to a variety of disease states is undergoing continuous refinement. The ECG has become so familiar to the general population and is a prominent icon for the technology of medicine having been incorporated into the logos of many medical organizations.
Every medical student has personal reflections on how interpretation of the ECG was first learned. ECG and rhythm interpretation is one of the fundamental skills that are learned during clinical clerkships in medical school. For emergency physicians, ECGs are interpreted countless times per day, with these interpretations forming the basis for life saving decision-making. In emergency medicine, the ECG is emblematic of the potential for missed diagnosis, if, for example, the ECG is misinterpreted or simply not done.
ECGs have become such an essential part of emergency medicine that they are often performed before the patient can be fully evaluated by the physician. Further, the ECG is often performed even before the patient is transported to the hospital. With the emphasis of reduced time to reperfusion for patients with ST elevation MI, or STEMI, delays in ECG acquisition can have disastrous consequences; conversely, the early use of the ECG in the prehospital setting can markedly reduce the time to hospital-based reperfusion in STEMI.6
The authors, Drs. Mattu and Brady, are widely known for their work in the science and clinical application of ECGs in the emergency setting. Given the realities of the practice of emergency medicine, the authors of ECGs for the Emergency Physician, Volume 2, have chosen to recreate the clinical setting by presenting the tracing with the brief clinical history. The reader is asked to interpret the tracing in the first half of each section, and answers are given in the second half of the section, for readers to check accuracy and thoroughness. The tracings in this text thus become the essential teaching file for clinicians to use in acquiring the in-depth understanding needed by emergency physicians. This book contains a vast array of ECG tracings that duplicates the experience of clinical work by demonstrating the commonly encountered ECG abnormalities. Whether this text is used as a reference or a challenging exercise, the reader will be exposed to 200 classic ECGs with extensive descriptions of the salient clinical points associated with each. Much as the ECG interpretation is an essential skill in emergency medicine, this text is essential reading for the emergency physician.
Robert E. O’Connor, MD, MPH
Professor and Chair
Department of Emergency Medicine
University of Virginia Health System
Charlottesville, Virginia
References
1. Einthoven W. Un nouveau galvanometre. Arch NeerlSc Ex Nat 1901;6:625.
2. Cooper JK. Electrocardiography 100 years ago. Origins, pioneers, and contributors. NewEnglJMed1986;315(7):461–4.
3. Braunwald E. (Ed) Heart Disease: A Textbook of Cardiovascular Medicine, 5th edn. Philadelphia: W.B. SaundersCo., 1997.
4. 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care—Part 8: Stabilization of the Patient With Acute Coronary Syndromes. Circulation 2005;112: IV-89–IV-110.
5. Van Mieghem C, Sabbe M, Knockaert D. The clinical value of the ECG in noncardiac conditions. Chest 2004; 125(4): 1561–76.
6. HenryTD, Sharkey SW, Burke MN, Chavez IJ, Graham KJ, Henry CR, Lips DL, Madison JD, Menssen KM, Mooney MR, Newell MC, Pedersen WR, Poulose AK, Traverse JH, Unger BT, Wang YL, Larson DM. A regional system to provide timely access to percuta neous coronary intervention for ST-elevation myocardial infarction. Circulation 2007;116(7):721–8.
Preface
The adult male with chest pain and diaphoresis ultimately diagnosed with STEMI. The fussy infant with a very rapid pulse found to have Wolff-Parkinson-White syndrome-related PSVT. The young adult female with altered mental status and a wide QRS complex demonstrating significant cardiovascular end-organ toxicity due to tricyclic antidepressant poisoning. The elderly female “found down,” pulseless and apneic presenting with a bradycardic PEA cardiac arrest rhythm. The hypothermic patient with bradycardia as well as significant J waves.
These clinical scenarios are quite familiar to the practicing emergency physician. In each presentation, the electrocardiogram (ECG) is a primary diagnostic tool used by the emergency physician in the early evaluation of these very ill patients. A significant number of the millions of patients cared for each year in emergency departments present with cardiovascular syndromes and/or issues related to the cardiovascular system. The widely recognized benefits of early diagnosis and rapid treatment of cardiovascular emergencies have only emphasized the importance of emergency physician competency in electrocardiographic interpretation. The emergency physician, frequently the first–if not the only-physician to evaluate such patients, is charged with the responsibility of rapid, accurate diagnosis followed by appropriate therapy delivered expeditiously. Emergency physicians are immediately available at all times of the day and night to care for patients with time-sensitive cardiovascular emergencies. This evaluation frequently involves the performance of and interpretation of the ECG. These interpretations often occur without the benefit of past knowledge of the patient, without the results of exhaustive prior evaluations, and without prior electrocardiograms for comparison –and usually in the midst of a busy, or even chaotic, emergency department environment.
Further emphasizing the importance of electrocardiography is the fact that it remains one of the most cost-effective and useful tests in medicine. It is inexpensive, rapid, and reliable. It can be performed at the bedside in the sickest of patients – by anyone with minimal training –often providing information that will make the difference between life and death. The knowledge to master this electrocardiography interpretation doesn’t require any special type of residency or fellowship training, and it doesn’t require thousands of dollars to be paid for travel and tuition at continuing medical education courses. It can be learned from books.
This text, ECGs for the Emergency Physician 2, continues with the case-based instruction and electrocardiographic experience that was so well-received in ECGs for the Emergency Physician 1. Like Volume 1, this Volume contains two hundred ECGs accompanied by brief, focused case histories. However, in response to the enthusiastic feedback from Volume 1, we have further increased the overall level of difficulty of the ECGs but without relying on esoterica–all cases are real emergency department presentations, the type that emergency physicians must always be ready to face. We’ve also added greater emphasis on dysrhythmias, including an initial section purely focused on dysrhythmia interpretation primarily from rhythms strips. Readers of Volume 1 enjoyed the pearls, pitfalls, and patient outcomes so we’ve added more. Readers expressed appreciation for the repetition of key points in the Commentary sections which helped emphasize important points, so we’ve maintained this. Readers also gave positive feedback regarding the use of illustrations in the Commentary section, so we’ve increased the use of explanatory illustrations as well. As with Volume 1, we continue to focus on teaching the intermediate and advanced-level practitioner, and thus there is no “basic” section or “introduction to ECG interpretation.” Those readers that are new to the art of ECG interpretation are referred to the multitude of ECG books on the market that focus on beginners’ skills.
Lastly, we’d like to emphasize that Volume 2 was not written as a replacement to, or alternative, to Volume 1 but rather as an extension of Volume 1. We strongly believe that although these two texts may be used individually, when used in combination they represent one of the most comprehensive and educational ECG collections ever assembled for emergency physicians and other acute health care providers. Our sincerest hope is that these books will help emergency physicians around the world to continue to save lives every day.
Amal Mattu and William Brady
Dedications
For my father, William J Brady, Sr, a good man.
William Brady
I would like to thank my wife, Sejal, for her constant support and patience; to my children Nikhil, Eleena, and Kamran for helping me keep balance in my life; to the faculty and residents of the University of Maryland Emergency Medicine Residency Program for their inspiration and for their ECG contributions; to Lauren Brindley and BMJ Books/Blackwell Publishing for supporting our work; to Dr. Bill Brady for his friendship, mentorship, and for being a true academic role model; and to emergency physicians around the world –your dedication to patient care and commitment to education are a constant source of inspiration and reminder of why I am so proud to be a member of this profession.
AmalMattu
Part 1
Focus on dysrhythmias
Case histories