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(BQ) Part 1 book ECG rounds presents the following contents: 47-year-old man presenting for preoperative evaluation prior to knee arthroscopy, 43-year-old asymptomatic man, 65-year-old woman complaining of 3 hours of severe epigastric “bloating.”,...
ECG ROUNDS Notice Medicine is an ever-changing science As new research and clinical experience broaden our knowledge, changes in treatment and drug therapy are required The authors and the publisher of this work have checked with sources believed to be reliable in their efforts to provide information that is complete and generally in accord with the standards accepted at the time of publication However, in view of the possibility of human error or changes in medical sciences, neither the authors nor the publisher nor any other party who has been involved in the preparation or publication of this work warrants that the information contained herein is in every respect accurate or complete, and they disclaim all responsibility for any errors or omissions or for the results obtained from use of the information contained in this work Readers are encouraged to confirm the information contained herein with other sources For example and in particular, readers are advised to check the product information sheet included in the package of each drug they plan to administer to be certain that the information contained in this work is accurate and that changes have not been made in the recommended dose or in the contraindications for administration This recommendation is of particular importance in connection with new or infrequently used drugs ECG ROUNDS Thomas S Metkus New York Chicago San Francisco Athens London Madrid Mexico City Milan New Delhi Singapore Sydney Toronto Copyright © 2014 by McGraw-Hill Education All rights reserved Except as permitted under the United States Copyright Act of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written permission of the publisher ISBN: 978-0-07-180764-7 MHID: 0-07-180764-0 The material in this eBook also appears in the print version of this title: ISBN: 978-0-07-180763-0, MHID: 0-07-180763-2 E-book conversion by codeMantra 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transmit, distribute, disseminate, sell, publish or sublicense the work or any part of it without McGraw-Hill Education’s prior consent You may use the work for your own noncommercial and personal use; any other use of the work is strictly prohibited Your right to use the work may be terminated if you fail to comply with these terms THE WORK IS PROVIDED “AS IS.” McGRAW-HILL EDUCATION AND ITS LICENSORS MAKE NO GUARANTEES OR WARRANTIES AS TO THE ACCURACY, ADEQUACY OR COMPLETENESS OF OR RESULTS TO BE OBTAINED FROM USING THE WORK, INCLUDING ANY INFORMATION THAT CAN BE ACCESSED THROUGH THE WORK VIA HYPERLINK OR OTHERWISE, AND EXPRESSLY DISCLAIM ANY WARRANTY, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE McGraw-Hill Education and its licensors not warrant or guarantee that the functions contained in the work will meet your requirements or that its operation will be uninterrupted or error free Neither McGraw-Hill Education nor its licensors shall be liable to you or anyone else for any inaccuracy, error or omission, regardless of cause, in the work or for any damages resulting therefrom McGraw-Hill Education has no responsibility for the content of any information accessed through the work Under no circumstances shall McGraw-Hill Education and/or its licensors be liable for any indirect, incidental, special, punitive, consequential or similar damages that result from the use of or inability to use the work, even if any of them has been advised of the possibility of such damages This limitation of liability shall apply to any claim or cause whatsoever whether such claim or cause arises in contract, tort or otherwise CONTENTS BY DIFFICULTY LEVEL Contributors, vii Dedication, ix Foreword, xi Preface, xiii Introduction: A focused step-wise guide to ECG interpretation, Level I (Cases 1-50), Level II (Cases 51-100), 209 Level III (Cases 101-150), 419 Index, 641 v vi n CONTENTS CONTENTS BY SUBJECT MATTER Tracings arranged by subject matter Contributors, vii Dedication, ix Foreword, xi Preface, xiii Normals, normal variants and artifacts Thomas S Metkus, MD and Sammy Zakaria, MD, MPH 4, 12, 60, 68, 254, 308, 388, 466 Chamber enlargement and hypertrophy Ramon A Partida, MD and Dipan A Desai, DO 52, 88, 140, 166, 336, 452, 518, 544 Ischemia Thomas S Metkus, MD 16, 24, 48, 112, 128, 144, 148, 174, 186, 194, 204, 226, 246, 264, 280, 316, 348, 376, 414, 436, 478, 484, 526, 556, 572, 614, 624, 636 Myocardium, pericardium, and pulmonary artery Narrow complex tachycardias Samuel C Volo, MD and Sammy Zakaria, MD, MPH 32, 100, 124, 132, 178, 198, 258, 290, 360, 400, 420, 448, 536, 584, 600 Thomas S Metkus, MD and Glenn A Hirsch, MD, MHS, FACC 36, 80, 116, 182, 190, 234, 324, 368, 424, 462, 492 Pacemakers Wide complex tachycardias Yee-Ping Sun, MD and Dipan A Desai, DO 104, 242, 304, 320, 332, 404, 456, 500, 514, 596, 628 Thomas S Metkus, MD and Sammy Zakaria, MD, MPH 64, 136, 272, 352, 380, 408, 476, 548, 564, 620 Ingestions, electrolyte abnormalities, and exposures Bradycardias and blocks Jonathan W Waks, MD and Dipan A Desai, DO 8, 20, 72, 84, 92, 96, 120, 162, 218, 276, 294, 340, 364, 384, 428, 440, 470, 496, 510, 530, 560, 588, 610 Matthew I Tomey, MD and Thomas S Metkus, MD 56, 76, 108, 152, 170, 222, 230, 268, 284, 372, 392, 396, 432, 504, 552, 568, 604 Syndromes, riddles, and miscellaneous arrhythmia Thomas S Metkus, MD and Sammy Zakaria, MD, MPH 28, 40, 44, 158, 210, 214, 238, 250, 298, 312, 328, 344, 356, 444, 488, 522, 540, 580, 592 CONTRIBUTORS Dipan A Desai, DO Clinical Associate Division of Cardiology Johns Hopkins University School of Medicine Johns Hopkins Bayview Medical Center Baltimore, Maryland Glenn A Hirsch, MD, MHS, FACC Adjunct Assistant Professor of Medicine Division of Cardiology Johns Hopkins University School of Medicine Associate Professor of Medicine Division of Cardiovascular Medicine Department of Medicine University of Louisville Louisville, Kentucky Thomas S Metkus, Jr, MD Fellow in Cardiovascular Medicine Division of Cardiology The Johns Hopkins Hospital Baltimore, Maryland Ramon A Partida, MD Fellow in Cardiovascular Medicine Division of Cardiology Massachusetts General Hospital Harvard Medical School Boston, Massachusetts Yee-Ping Sun, MD Clinical Cardiology Fellow Division of Cardiology Department of Medicine Columbia University Medical Center New York-Presbyterian Hospital New York, New York Matthew I Tomey, MD Chief Fellow Department of Cardiology The Mount Sinai Hospital New York, New York Samuel C Volo, MD Cardiology Fellow Division of Cardiology New York-Presbyterian Hospital Weill Cornell Medical Center New York, New York Jonathan W Waks, MD Clinical Cardiology Fellow Division of Cardiovascular Disease Beth Israel Deaconess Medical Center Clinical Fellow in Medicine Harvard Medical School Boston, Massachusetts Sammy Zakaria, MD, MPH Assistant Professor of Medicine Division of Cardiology Johns Hopkins University School of Medicine Baltimore, Maryland vii This page intentionally left blank Dedication To my parents: you are my first role models both as physicians and as people To mentors too numerous to list here, in particular Drs Joseph Loscalzo, Steve Schulman, and the late Ken Baughman: thank you!! For Kate and for Hailey: it’s all for you, always ix 194 n DIFFICULTY LEVEL Case #48 A 78-year-old man presents with substernal chest pain at rest DIFFICULTY LEVEL n 195 QUESTION 48-1 What abnormality is present? 196 n DIFFICULTY LEVEL DIFFICULTY LEVEL n 197 ANSWER 48-1 What abnormality is present? There is sinus tachycardia at a rate slightly higher than 100 beats/min Examining the rhythm strip, the final (17th) QRS complex and its associated P wave represent a premature atrial contraction The axis and intervals are normal Prominent ST-segment depressions are present in the anterior leads of V2 through V4, with ST-segment abnormalities present to a lesser degree in the lateral leads I, V5, and V6 as well as the inferior leads II and aVF There are no pathologic Q waves The ST-segment depressions are consistent with subendocardial ischemia Causes of subendocardial ischemia include primary acute coronary syndromes as well as clinical syndromes that globally decrease myocardial oxygen supply such as aortic stenosis or severe anemia, or conditions that increase myocardial oxygen demand such as severe sepsis or highoutput heart failure This patient underwent coronary angiography that revealed severe 3-vessel coronary disease with greater than 90% stenoses in the left anterior descending, left circumflex, and right coronary arteries He was referred for coronary artery bypass grafting When considering the ECG findings in a patient with myocardial infarction, it is important to note that, unlike the distribution of ST-segment elevations that can suggest the specific coronary artery involved, the distribution of ST-segment depressions cannot be used to localize the ischemia to a particular coronary territory 198 n DIFFICULTY LEVEL Case #49 An 83-year-old woman with severe chronic obstructive pulmonary disease is admitted to the hospital with communityacquired pneumonia DIFFICULTY LEVEL n 199 QUESTIONS 49-1 Interpret this ECG: what is the rhythm? 49-2 Why is QRS complex 18 wider than the others? 49-3 What are risk factors for development of this arrhythmia, and how is it managed? 200 n DIFFICULTY LEVEL DIFFICULTY LEVEL n 201 ANSWERS 49-1 Interpret this ECG: what is the rhythm? The heart rate is rapid and the QRS complexes are narrow with the exception of the 18th QRS complex The average ventricular rate can be estimated by counting the 24 QRS complexes across the 10-second rhythm strip, then multiplying by to arrive at 144 beats/min The RR intervals are irregular, and the irregularity lacks a pattern Thus, this is an “irregularly irregular” narrow-complex tachycardia, which implies that the rhythm is either atrial fibrillation or multifocal atrial tachycardia In this case, there are visible P waves present before each QRS; however, the P waves have varying morphology In the V1 rhythm strip, there are at least three different morphologies of P wave: the first, “P1,” is tall and peaked, is associated with a slightly longer PR interval (approximately 120 milliseconds), and can be found preceding the first, third, fifth, seventh, ninth, twelfth, and fourteenth QRS complexes The second P wave “P2,” has a tiny initial negative deflection and then a smaller positive peak and a shorter PR interval (approximately 100 milliseconds), and can be found preceding the second, fourth, sixth, eighth, tenth, eleventh, and thirteenth QRS complexes The third P-wave morphology can be seen prior to the final QRS complex on the strip, with a smooth positive deflection and an even longer PR interval of approximately 160 milliseconds This makes the diagnosis of multifocal atrial tachycardia (MAT) most likely Within the ST segment of the 16th QRS complex is a nonconducted, or blocked, P wave Otherwise, the axis is normal, and there is no evidence of ischemia or hypertrophy 202 n DIFFICULTY LEVEL ANSWERS (Cont.) 49-2 Why is QRS complex 18 wider than the others? This finding is secondary to Ashman’s phenomenon, which is sometimes associated with irregular narrow-complex tachycardias Ashman’s phenomenon occurs when a long RR interval is followed by a short RR interval, as is the case with the RR interval between QRS complexes 16 and 17 (500 milliseconds), and the interval between QRS complexes 17 and 18 (340 milliseconds) The longer the RR interval, the longer the refractory period When a short RR interval abruptly follows a long RR interval, the supraventricular impulse is conducted with aberrancy—right bundle branch block aberrancy in this case The first and fifth QRS complexes demonstrate incomplete right bundle branch block also consistent with Ashman’s phenomenon 49-3 What are risk factors for development of this arrhythmia, and how is it managed? MAT is an arrhythmia that is often seen in patients with intrinsic lung disease It is associated with COPD, asthma, pneumonia, pulmonary embolism, hypokalemia, and hypomagnesemia The mainstay of treatment for MAT is to treat the underlying cause AV nodal agents including calcium channel blockers and β-blockers can be used Electrolytes including calcium, potassium, and magnesium should be aggressively repleted This page intentionally left blank 204 n DIFFICULTY LEVEL Case #50 A 48-year-old woman with diabetes and smoking history presents with nausea, diaphoresis, and upper epigastric discomfort DIFFICULTY LEVEL n 205 QUESTIONS 50-1 What is the diagnosis? 50-2 Which coronary artery might be causing the symptoms? 206 n DIFFICULTY LEVEL DIFFICULTY LEVEL n 207 ANSWERS 50-1 What is the diagnosis? Sinus rhythm is present at a rate of 75 beats/min Axis is normal The QRS complex is narrow but has an RSR′ configuration in lead V1 consistent with incomplete right bundle branch block, sometimes called right ventricular conduction delay There are ST-segment elevations with small Q waves in the inferior leads II, III, and aVF with slight and subtle ST-segment elevation in leads V5 and V6 There is 0.5 mm of ST-segment depression in lead aVL with ST-segment depression also seen in leads V2 and V3 In the setting of inferior infarction, ST-segment depression anteriorly often connotes posterior infarction; that is, posterior ST-segment elevation typically manifests as ST-segment depression in the anterior leads The overall diagnosis, therefore, is inferoposterolateral myocardial ischemia with inferior infarction 50-2 Which coronary artery might be causing the symptoms? Inferior infarction is usually due to occlusion of the right coronary artery and less commonly due to occlusion of a dominant left circumflex artery In this patient, the fact that the magnitude of ST-segment elevation is greater in lead II (which is oriented leftward) than lead III (which is oriented rightward), and the presence of ST-segment elevations in the lateral precordial leads suggests the possibility that the left circumflex is the infarct-related artery At coronary angiography, a large, dominant left circumflex coronary was occluded in the mid portion and was successfully stented This page intentionally left blank ... Introduction: A focused step-wise guide to ECG interpretation, Level I (Cases 1- 50), Level II (Cases 51- 100), 209 Level III (Cases 10 1 -15 0), 419 Index, 6 41 v vi n CONTENTS CONTENTS BY SUBJECT MATTER... Ischemia Thomas S Metkus, MD 16 , 24, 48, 11 2, 12 8, 14 4, 14 8, 17 4, 18 6, 19 4, 204, 226, 246, 264, 280, 316 , 348, 376, 414 , 436, 478, 484, 526, 556, 572, 614 , 624, 636 Myocardium, pericardium, and pulmonary... Sammy Zakaria, MD, MPH 32, 10 0, 12 4, 13 2, 17 8, 19 8, 258, 290, 360, 400, 420, 448, 536, 584, 600 Thomas S Metkus, MD and Glenn A Hirsch, MD, MHS, FACC 36, 80, 11 6, 18 2, 19 0, 234, 324, 368, 424,