Additional Information
Book Details
Abstract
Huzar's ECG and 12-Lead Interpretation, 5th Edition, by Keith Wesley, M.D., helps you correlate ECG interpretation with clinical findings to identify and address selected heart rhythms. The text is structured to match the order in which you learn specific skills: ECG components are presented first, followed by rhythm interpretation and clinical implications. Take-Home Points, key definitions, chapter review questions, and practice strips help you understand and retain complex information
- NEW! Discusses the difference between sinus arrest and SA block to help clarify concepts that learners often find confusing.
- UPDATED! STEMI and NSTEMI treatment guidelines updated to the latest standards.
- Coverage of both basic and advanced concepts incorporates the latest research developments and provides material pertinent to both beginning and experienced prehospital care providers.
- UPDATED and EXPANDED! Key characteristics of each heart rhythm are summarized to allow you to learn or review each rhythm at a glance.
- Patient care algorithms outline step-by-step management and treatment, correlating ECG interpretation with history and exam findings.
- Advanced treatment content, such as complete coverage of thrombus formation, treatment, and management, offers critical information for both hospital and prehospital settings.
- UPDATED AND EXPANDED! Key definitions define important terms right on the page, near relevant content, making it unnecessary to flip to the back-of-book glossary while reading or studying.
- Key definitions, chapter review questions, and glossary updated to reflect new content.
- Chapter review questions (with answers in an appendix) test your understanding of key topics.
- Appendix with 200+ practice strips, questions, and answer keys reinforces major concepts and ties information together.
- UPDATED! Glossary defines key terms, supplementing the on-page Key Definitions.
- Expert authorship from Dr. Keith Wesley, who has been involved in EMS since 1989 and is a board-certified emergency medicine physician.
- Self-assessment answer key allows you to check their own work for self-evaluation.
- Chapter outlines offer a quick overview of each chapter’s content.
Table of Contents
| Section Title | Page | Action | Price |
|---|---|---|---|
| Front Cover | Cover | ||
| HUSZAR’S ECG AND 12-LEAD INTERPRETATION | i | ||
| HUSZAR’S ECG AND 12-LEAD INTERPRETATION | iii | ||
| Copyright | iv | ||
| Dedication | v | ||
| ABOUT THE AUTHOR | vi | ||
| FOREWORD | vii | ||
| PUBLISHER’S NOTE | viii | ||
| PREFACE | ix | ||
| ECG KEYS BOXES | ix | ||
| AUTHOR’S NOTES | ix | ||
| KEY DEFINITIONS | ix | ||
| TAKE-HOME POINTS | ix | ||
| CHAPTER REVIEW QUESTIONS | ix | ||
| ACKNOWLEDGMENTS | x | ||
| PUBLISHER’S ACKNOWLEDGMENTS | x | ||
| CONTENTS | xi | ||
| 1 - Anatomy and Physiology of the Heart | 1 | ||
| CARDIAC ANATOMY AND PHYSIOLOGY | 1 | ||
| Composition | 1 | ||
| Protection | 1 | ||
| Circulation | 2 | ||
| RIGHT HEART | 2 | ||
| LEFT HEART | 3 | ||
| ATRIAL AND VENTRICULAR DIASTOLE AND SYSTOLE | 3 | ||
| ELECTRICAL CONDUCTION SYSTEM OF THE HEART | 3 | ||
| CARDIAC CELLS | 6 | ||
| Myocardial Cells | 6 | ||
| Pacemaker Cells | 6 | ||
| ELECTROPHYSIOLOGY OF THE HEART | 6 | ||
| Resting State of the Cardiac Cell | 7 | ||
| Depolarization and Repolarization | 7 | ||
| Threshold Potential | 8 | ||
| Action Potential | 8 | ||
| REFRACTORY PERIODS | 9 | ||
| Automaticity | 9 | ||
| Dominant and Escape Pacemakers of the Heart | 10 | ||
| ENHANCED AUTOMATICITY | 10 | ||
| REENTRY | 11 | ||
| TRIGGERED ACTIVITY | 11 | ||
| AUTONOMIC NERVOUS SYSTEM CONTROL OF THE HEART | 11 | ||
| TAKE-HOME POINTS | 13 | ||
| 2 - ECG Leads and Cardiac Monitoring | 16 | ||
| BASIC ECG CONCEPTS | 16 | ||
| Electrical Basis of the ECG | 16 | ||
| ECG Paper | 16 | ||
| BASIC COMPONENTS OF A NORMAL ECG | 17 | ||
| ECG LEADS | 17 | ||
| Lead Basics | 17 | ||
| Bipolar Leads | 18 | ||
| MONITORING LEAD II | 18 | ||
| MONITORING LEADS I AND III | 19 | ||
| MODIFIED CHEST LEADS | 19 | ||
| Unipolar Leads | 21 | ||
| ACQUIRING A QUALITY ECG | 22 | ||
| Artifacts | 22 | ||
| QRS Size and Wandering Baseline | 23 | ||
| TAKE-HOME POINTS | 23 | ||
| 3 - Components of the ECG Waveform | 25 | ||
| WAVES | 25 | ||
| P WAVE | 25 | ||
| Normal Sinus P Wave | 25 | ||
| CHARACTERISTICS | 25 | ||
| Origin\r | 25 | ||
| Relationship to cardiac anatomy and physiology\r | 25 | ||
| 4 - Step-by-Step ECG Interpretation | 51 | ||
| SYSTEMATIC APPROACH TO ECG ANALYSIS | 51 | ||
| STEP ONE: DETERMINE THE RATE | 51 | ||
| Six-Second Method | 52 | ||
| Example. You count eight QRS complexes in a 6-second interval. A minute can be divided into ten 6-second intervals, so we’ll mul... | 52 | ||
| Rate Calculator Ruler Method | 52 | ||
| R-R Interval Method | 52 | ||
| METHOD 1 | 52 | ||
| METHOD 2 | 56 | ||
| METHOD 3 | 56 | ||
| METHOD 4 | 58 | ||
| Rule of 300 | 58 | ||
| Example. If B is halfway between the dark lines labeled 150 and 100, the rate is about 125 beats/min | 59 | ||
| STEP TWO: DETERMINE REGULARITY | 59 | ||
| Regular | 60 | ||
| Irregular | 60 | ||
| STEP THREE: IDENTIFY AND ANALYZE THE P, P’, F, OR F WAVES | 63 | ||
| STEP FIVE: IDENTIFY AND ANALYZE THE QRS COMPLEXES | 68 | ||
| STEP SIX: DETERMINE THE ORIGIN OF THE RHYTHM | 72 | ||
| STEP SEVEN: IDENTIFY THE RHYTHM | 72 | ||
| STEP EIGHT: ASSESS CLINICAL SIGNIFICANCE | 72 | ||
| TAKE-HOME POINTS | 75 | ||
| 5 - Sinus Rhythms\r | 77 | ||
| NORMAL SINUS RHYTHM | 77 | ||
| Characteristics | 77 | ||
| Rate. 60 to 100 beats/min. This is the normal resting rate in a healthy adult | 77 | ||
| Regularity. Regular pattern with equal R-R and P-P intervals. There are no dropped or blocked QRS complexes | 77 | ||
| P wave. P waves are identical, precede each QRS complex, and are positive (upright) in lead II, indicating that they originated ... | 77 | ||
| PR interval. Normal (less than 0.20 second) and constant, but may vary slightly with the rate | 77 | ||
| R-R and P-P intervals. May be equal or vary slightly. The difference between the longest and shortest R-R (or P-P) interval is u... | 77 | ||
| Conduction ratio. A P wave appears before every QRS complex, and a QRS complex follows each P wave. This is a 1:1 ratio, indicat... | 77 | ||
| QRS complex. Follows each P wave. Duration is normally 0.12 second or less, but it may be prolonged (longer than 0.12 second) if... | 77 | ||
| Origin. SA node | 77 | ||
| Clinical Significance | 77 | ||
| SINUS ARRHYTHMIA | 79 | ||
| Characteristics | 79 | ||
| Rate. 60 to 100 beats/min. Occasionally, the rate may slow to slightly less than 60 or increase to slightly more than 100 beats/... | 79 | ||
| Regularity. Sinus arrhythmia is regularly irregular as the rate gradually rises and falls. These rate changes occur in cycles | 79 | ||
| P wave. P waves are identical, precede each QRS complex, and are positive (upright) in lead II, indicating normal depolarization... | 79 | ||
| PR interval. Normal and constant | 79 | ||
| R-R interval. Unequal. In sinus arrhythmia, the difference between the longest and shortest R-R intervals is greater than 0.04 s... | 79 | ||
| Conduction ratio. A P wave appears before every QRS complex, and a QRS complex follows each P wave. This is a 1:1 ratio, indicat... | 79 | ||
| QRS complex. Usually follows each P wave and has a normal duration unless an intraventricular conduction disturbance, such as a ... | 79 | ||
| Origin. SA node | 79 | ||
| 6 - Atrial Rhythms | 88 | ||
| PREMATURE ATRIAL COMPLEXES\r | 88 | ||
| Characteristics | 88 | ||
| Rate. Same as that of the underlying rhythm | 88 | ||
| Regularity. Irregular at the period of time surrounding the PAC | 88 | ||
| P wave. A PAC is diagnosed when a P wave accompanied by a QRS complex occurs earlier than the next expected sinus P wave. The pr... | 88 | ||
| PR interval. May be normal but is usually different from that of the underlying rhythm. Variable length | 88 | ||
| R-R interval. The P-P′ interval of the PAC is shorter than the P-P interval of the underlying rhythm because the PAC occurs earl... | 89 | ||
| QRS complex. Usually resembles that of the underlying rhythm because conduction of the electrical impulse through the bundle bra... | 89 | ||
| Conduction ratio. 1:1 when the PAC is conducted, and 1:0 when nonconducted or blocked | 89 | ||
| Patterns. The following are the various forms in which PACs may appear | 90 | ||
| Origin. PACs originate at an ectopic site in the atria outside the SA node, such as the AV junction. They may originate from a s... | 90 | ||
| Causes | 90 | ||
| Clinical Significance | 90 | ||
| WANDERING ATRIAL PACEMAKER | 91 | ||
| Characteristics | 91 | ||
| Rate. Sixty to 100 beats/min but may be slower. Usually, the rate gradually slows as the pacemaker site shifts from the SA node ... | 91 | ||
| Regularity. Slightly irregular | 91 | ||
| P wave. The P wave changes in size, shape, and direction over the course of several beats. It varies in lead II from positive (u... | 91 | ||
| PR interval. Decreases gradually from about 0.20 second to 0.12 second or less as the pacemaker site shifts from the SA node to ... | 91 | ||
| P-P and R-R intervals. The P-P′ (or P′-P) and R-R intervals are usually unequal but may become nearly equal if the rate is fast.... | 91 | ||
| Conduction ratio. A P or P′ wave appears before every QRS complex, and a QRS complex occurs after each P wave. This is a 1:1 rat... | 91 | ||
| QRS complex. Normal unless a preexisting intraventricular conduction disturbance (such as a bundle branch block) is present. A Q... | 91 | ||
| Origin. The pacemaker site shifts back and forth between the SA node and one or more ectopic pacemaker sites in the atria | 91 | ||
| Causes | 91 | ||
| Clinical Significance | 91 | ||
| ATRIAL TACHYCARDIA AND MULTIFOCAL ATRIAL TACHYCARDIA | 93 | ||
| Characteristics | 93 | ||
| Rate. One hundred sixty to 240 beats/min for atrial tachycardia and 100 to 150 beats/min for MAT. The ventricular rate is usuall... | 93 | ||
| Regularity. Regular if the AV conduction ratio is constant but variable if the AV conduction ratio changes | 93 | ||
| P wave. There are no normal P waves in atrial tachycardia because the ectopic P wave suppresses the normal automaticity of the S... | 93 | ||
| PR interval. The PR interval is usually normal and constant in ectopic atrial tachycardia. In MAT, the PR interval usually varie... | 93 | ||
| P′-P′ and R-R intervals. P′-P′ and R-R intervals are equal if the AV conduction ratio is constant. But if the ratio varies (for ... | 93 | ||
| Conduction ratio. In most patients with untreated atrial tachycardia not caused by digitalis intoxication, and in which the atri... | 93 | ||
| QRS complex. The QRS complex is normal unless a preexisting intraventricular conduction disturbance (such as a bundle branch blo... | 93 | ||
| Origin. Atrial tachycardia originates from an ectopic site in the atria—that is, any atrial site outside the SA node. When it or... | 93 | ||
| Causes | 93 | ||
| Clinical Significance | 95 | ||
| ATRIAL FLUTTER | 95 | ||
| Characteristics | 95 | ||
| Rate. The rate of atrial flutter depends on the conduction ratio between the atria and ventricles. With a 1:1 conduction ratio, ... | 95 | ||
| Regularity. Regular when the AV conduction is constant. Irregularly irregular when the AV conduction is variable | 95 | ||
| P wave. As discussed in Chapter 4, the P wave can assume many shapes. In atrial flutter, the ectopic atrial pacemaker fires rapi... | 95 | ||
| F wave. The F wave represents depolarization of the atria in an abnormal direction, followed by atrial repolarization. Atrial de... | 95 | ||
| R-R interval. Equal if the AV conduction ratio is constant. Unequal if the AV conduction ratio varies | 98 | ||
| Conduction ratio. Usually 2:1. This ratio indicates that every other F wave is followed by a QRS complex. The conduction ratio i... | 98 | ||
| QRS complex. Normal except in the presence of a preexisting intraventricular conduction disturbance (such as a bundle branch blo... | 98 | ||
| Origin. Atrial flutter originates in an atrial site outside the SA node, usually located low in the atria near the AV node. Atri... | 98 | ||
| Causes | 98 | ||
| Clinical Significance | 98 | ||
| ATRIAL FIBRILLATION | 98 | ||
| Characteristics | 99 | ||
| Rate. Typically, the atrial rate is 350 to 600 (average 400) beats/min, but it can be as high as 700. The ventricular rate is us... | 99 | ||
| Regularity. Irregularly irregular | 100 | ||
| P wave. As discussed in Chapter 4 there are no normal P waves in atrial fibrillation. Instead, the chaotic rapid firing of the m... | 100 | ||
| f wave. The f waves seen in atrial fibrillation represent abnormal, chaotic (disorganized), incomplete depolarization of small i... | 100 | ||
| R-R interval. The R-R intervals are typically unequal. When no impulse is transmitted through the AV node, complete AV dissociat... | 101 | ||
| Conduction ratio. In atrial fibrillation, less than one-half, and often less than one-third, of the atrial electrical impulses a... | 101 | ||
| QRS complex. The QRS complexes are normal unless a preexisting intraventricular conduction disturbance (such as a bundle branch ... | 101 | ||
| Origin. Atrial fibrillation originates from multiple ectopic sites in the atria, generating electrical impulses chaotically | 101 | ||
| Causes | 101 | ||
| Clinical Significance | 101 | ||
| TAKE-HOME POINTS | 101 | ||
| 7 - Junctional Rhythms | 104 | ||
| PREMATURE JUNCTIONAL COMPLEX | 104 | ||
| Characteristics | 104 | ||
| Rate. That of the underlying rhythm | 104 | ||
| Regularity. Irregular over the period of time encompassing the PJC | 104 | ||
| P wave. May or may not be associated with the PJC. If present, it is a P′ wave, varying in size, shape, and direction from a no... | 104 | ||
| PR interval. A P′R interval exists if the P′ precedes the QRS. An RP′ interval exists if the P′ follows the QRS in less than 0.1... | 104 | ||
| R-R interval. The R-R interval is unequal when PJCs are present. The interval between the PJC and the preceding QRS complex is s... | 104 | ||
| Conduction ratio. The impulse causing the PJC originates above the ventricles. It is conducted down the bundle of His, resulting... | 104 | ||
| QRS complex. Usually resembles that of the underlying rhythm. If the site within the AV junction discharges too soon after the p... | 106 | ||
| Frequency of occurrence and pattern. The following are the various forms in which PJCs may appear | 106 | ||
| Causes | 107 | ||
| Clinical Significance | 107 | ||
| JUNCTIONAL ESCAPE RHYTHM | 107 | ||
| 8 - Ventricular Rhythms | 114 | ||
| PREMATURE VENTRICULAR COMPLEX | 114 | ||
| Characteristics | 114 | ||
| Rate. Same as the underlying rhythm | 114 | ||
| Regularity. Irregular | 114 | ||
| P wave. If present, it is generated by the underlying rhythm and has no relation to the PVC. Typically, a PVC does not disturb t... | 114 | ||
| PR interval. Not associated with this complex | 114 | ||
| R-R interval. Intervals are unequal. The R-R interval between the PVC and the preceding QRS complex of the underlying rhythm is ... | 114 | ||
| QRS complex. The QRS complex of the PVC typically appears prematurely, without an ectopic P wave preceding the next expected QRS... | 114 | ||
| Frequency and pattern. The following are the various forms in which PVCs may appear | 117 | ||
| Causes | 117 | ||
| Clinical Significance | 118 | ||
| VENTRICULAR TACHYCARDIA | 118 | ||
| Characteristics | 118 | ||
| Rate. More than 100 beats/min. Usually between 150 and 200 beats/min | 118 | ||
| Regularity. Regular | 118 | ||
| P wave. A normal atrial P wave is absent | 118 | ||
| PR interval. Because the ectopic pacemaker originates below the AV node, there is no PR interval associated with this rhythm | 118 | ||
| R-R interval. Intervals are equal to one another but may vary slightly if the rate changes | 118 | ||
| Conduction ratio. Impulse originates below the AV node; therefore there is AV dissociation | 118 | ||
| QRS complex. Exceeds 0.12 second and is usually distorted and bizarre—often notched. Followed by a large, discordant T wave. Usu... | 118 | ||
| Origin. Begins in an ectopic pacemaker in the bundle branches, Purkinje network, or ventricular myocardium | 118 | ||
| Forms of Ventricular Tachycardias | 118 | ||
| Monomorphic V-tach. V-tach with QRS complexes that are of the same or almost the same shape, size, and direction | 118 | ||
| Bidirectional V-tach. V-tach with two distinctly different, alternating QRS complexes. These complexes originate in two differen... | 118 | ||
| Polymorphic V-tach. V-tach in which the QRS complexes differ markedly in shape, size, and direction from beat to beat. (Recall t... | 118 | ||
| Torsades de pointes (TdP). A form of polymorphic V-tach characterized by QRS complexes that gradually change back and forth from... | 120 | ||
| Causes | 120 | ||
| Clinical Significance | 121 | ||
| VENTRICULAR FIBRILLATION | 121 | ||
| Characteristics | 122 | ||
| Rate. No coordinated ventricular beats are present. The ventricles contract from 300 to 500 times a minute in an unsynchronized,... | 122 | ||
| Regularity. Totally irregular | 122 | ||
| PR interval. Absent | 122 | ||
| R-R interval. Absent | 122 | ||
| Conduction ratio. VF originates below the AV node. As a result, there is AV dissociation | 122 | ||
| QRS complex. Absent | 122 | ||
| Characteristics of ventricular fibrillatory waves | 122 | ||
| Relationship to cardiac anatomy and physiology. Ventricular fibrillatory waves represent abnormal, chaotic, incomplete ventricul... | 122 | ||
| Onset and end. Often cannot be determined with certainty | 122 | ||
| Direction. Varies randomly from positive (upright) to negative (inverted) | 122 | ||
| Duration. Cannot be measured with certainty | 122 | ||
| Amplitude. Varies from less than 1 mm to about 10 mm. Generally, if the fibrillatory waves are small (less than 3 mm), the rhyth... | 122 | ||
| Shape. Markedly dissimilar, bizarre waves that vary from rounded to pointed | 124 | ||
| Origin. Multiple ectopic sites in the Purkinje network and ventricular myocardium | 124 | ||
| Causes | 124 | ||
| Clinical Significance | 124 | ||
| VENTRICULAR ESCAPE RHYTHM (IDIOVENTRICULAR RHYTHM) | 124 | ||
| Characteristics | 124 | ||
| Rate. Less than 40 beats/min; usually between 20 and 40 beats/min, but it may be less | 124 | ||
| Regularity. Regular | 124 | ||
| P wave. If present, it has no set relation to the QRS complex of the ventricular escape rhythm and appears independently at a ra... | 124 | ||
| PR interval. Absent | 124 | ||
| R-R interval. Intervals are equal to one another | 124 | ||
| Conduction ratio. The pacemaker is below the AV node. Therefore there is AV dissociation | 124 | ||
| QRS complex. The QRS complex exceeds 0.12 second and appears bizarre. Sometimes the shape of the QRS complex varies as the site ... | 124 | ||
| Origin. Originates in an escape pacemaker in the bundle branches, Purkinje network, or ventricular myocardium | 124 | ||
| 9 - Atrioventricular Blocks | 131 | ||
| FIRST-DEGREE AV BLOCK | 131 | ||
| Characteristics | 131 | ||
| Rate. That of the underlying sinus or atrial rhythm. The atrial and ventricular rates are typically the same. The rate may be sl... | 131 | ||
| Regularity. Regular because it originates from the sinoatrial (SA) node or an atrial pacemaker | 131 | ||
| P wave. The P waves are identical to one another, and a P wave precedes each QRS complex. Waves are upright in lead II and have ... | 131 | ||
| PR interval. Prolonged (greater than 0.20 second) and of consistent duration | 131 | ||
| R-R interval. Regular and same as those of the underlying rhythm | 131 | ||
| Conduction ratio. There is a P wave for every QRS complex and a QRS complex for every P wave; therefore the conduction ratio is ... | 131 | ||
| QRS complex. Usually normal, but the QRS complex may be abnormal because of a preexisting intraventricular conduction disturbanc... | 131 | ||
| Origin. The SA node or an atrial pacemaker | 131 | ||
| Causes | 131 | ||
| SECOND-DEGREE TYPE I AV BLOCK (WENCKEBACH) | 133 | ||
| Characteristics | 133 | ||
| Rate. That of the underlying sinus or atrial rhythm. The ventricular rate is less than the atrial rate because there are absent ... | 133 | ||
| Regularity. Patterned irregularity, with a pattern of group beats. This occurs because the SA node impulse is slowed progressive... | 133 | ||
| P wave. P waves are identical to one another. When present, the P wave precedes the QRS complex. The P wave associated with the ... | 133 | ||
| PR interval. Initially normal but may be longer. They gradually lengthen until a QRS complex fails to appear after a P wave (non... | 133 | ||
| R-R interval. Unequal. As the PR interval gradually lengthens, the R-R interval gradually decreases until the P wave is no longe... | 133 | ||
| Conduction ratio. Usually 5:4, 4:3, or 3:2, but it may be 6:5, 7:6, etc. An AV conduction ratio of 5:4, for example, indicates t... | 133 | ||
| QRS complex. Usually normal in duration and shape, but it may be abnormal because of a preexisting intraventricular conduction d... | 133 | ||
| Origin. SA node or an atrial pacemaker | 133 | ||
| Causes | 133 | ||
| 10 - Implanted Pacemaker Rhythms | 143 | ||
| PACEMAKERS\r | 143 | ||
| TYPES OF PACEMAKERS | 143 | ||
| Fixed Rate or Demand | 143 | ||
| Single or Dual Chamber | 144 | ||
| SINGLE CHAMBER | 144 | ||
| Atrial Demand Pacemaker (AAI). An AAI pacemaker senses spontaneously occurring P waves and paces the atria when they do not appe... | 144 | ||
| DUAL CHAMBER | 145 | ||
| Atrial Synchronous Pacemaker (VDD). A VDD pacemaker paces only in the ventricle. This device senses spontaneously occurring P wa... | 145 | ||
| Atrioventricular Sequential Pacemaker (DDI). A DDI pacemaker senses spontaneously occurring QRS complexes and paces both the atr... | 146 | ||
| Optimal Sequential Pacemaker (DDD). A DDD pacemaker senses spontaneously occurring P waves and QRS complexes and responds as fol... | 146 | ||
| PACEMAKER RHYTHM | 147 | ||
| Characteristics | 147 | ||
| Rate. Usually 60 to 70 beats/min, depending on its preset rate of firing. If the pacemaker rate is greater than 90 beats/min, it... | 147 | ||
| Rhythm. Regular if the pacemaker is pacing continuously. The ventricular rate may be irregular when the pacemaker is pacing on d... | 147 | ||
| P wave. If present, they may occur spontaneously or be induced by a pacemaker lead positioned in one of the atria. When not foll... | 147 | ||
| PR interval. The PR interval in atrial synchronous and dual-paced AV sequential pacemakers is within normal limits | 147 | ||
| R-R interval. Intervals are equal if the pacemaker is pacing constantly. When the pacemaker-induced QRS complexes are interspers... | 147 | ||
| QRS complex. The pacemaker-induced QRS complex is typically longer than 0.12 seconds (Fig. 10.9) | 148 | ||
| Pacemaker site. The pacemaker site of a cardiac pacemaker is an electrode. It is usually located in the tip of the pacemaker lea... | 148 | ||
| Clinical Significance | 148 | ||
| PACEMAKER MALFUNCTION | 148 | ||
| Failure to Sense | 148 | ||
| Failure to Capture | 149 | ||
| IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR THERAPY | 149 | ||
| ICD Devices | 150 | ||
| ICD Malfunction | 150 | ||
| TAKE-HOME POINTS | 151 | ||
| 11 - Treatment of Rhythm Disturbances | 153 | ||
| ASSESSING THE PATIENT | 153 | ||
| Stable Versus Unstable | 153 | ||
| TREATING THE PATIENT | 154 | ||
| Cardioversion and Defibrillation | 154 | ||
| Transcutaneous Pacing | 154 | ||
| INDICATIONS | 154 | ||
| Pharmacologic Therapy | 155 | ||
| ATROPINE | 155 | ||
| Indications. Atropine is usually effective in treating the following symptomatic bradycardias and is indicated in their initial ... | 155 | ||
| Contraindications, end points, and adverse effects. Observe the following contraindications and cautions when administering atro... | 155 | ||
| Vasopressors | 155 | ||
| EPINEPHRINE | 155 | ||
| VASOPRESSIN | 156 | ||
| DOPAMINE | 156 | ||
| NOREPINEPHRINE | 156 | ||
| DOBUTAMINE | 156 | ||
| ISOPROTERENOL | 156 | ||
| Antidysrhythmics | 156 | ||
| ADENOSINE | 156 | ||
| AMIODARONE | 156 | ||
| Indications. Amiodarone is indicated in the following conditions | 156 | ||
| Contraindications, end points, and adverse effects. The major adverse effects of amiodarone are hypotension and bradycardia, whi... | 156 | ||
| LIDOCAINE | 156 | ||
| Indications. The indications for the use of lidocaine include | 156 | ||
| Contraindications, end points, and adverse effects. Toxic reactions and side effects include slurred speech, altered consciousne... | 157 | ||
| PROCAINAMIDE | 157 | ||
| Indications. Procainamide may be considered in the following conditions | 157 | ||
| Contraindications, end points, and adverse effects. The administration of procainamide must be stopped when specific end points ... | 157 | ||
| MAGNESIUM | 157 | ||
| IBUTILIDE | 157 | ||
| Calcium-Channel Blockers | 157 | ||
| Indications. These medications are indicated in the following circumstances | 157 | ||
| Beta Blockers | 158 | ||
| Indications. For acute tachycardia, these agents are indicated for rate control under the following conditions | 158 | ||
| Oxygen | 158 | ||
| BRADYCARDIA (FIG. 11.1) | 158 | ||
| INDICATIONS FOR TREATMENT | 158 | ||
| CONTRAINDICATIONS FOR TREATMENT, END POINTS, AND ADVERSE EFFECTS | 158 | ||
| Symptomatic Bradycardia | 159 | ||
| 12 - The 12-Lead ECG: Leads and Axis | 174 | ||
| LEADS | 174 | ||
| Standard (Bipolar) Limb Leads | 174 | ||
| Lead Axis | 174 | ||
| Electrical Planes | 177 | ||
| FRONTAL PLANE | 177 | ||
| HORIZONTAL PLANE | 177 | ||
| Unipolar Leads | 177 | ||
| AUGMENTED (UNIPOLAR) LEADS | 177 | ||
| PRECORDIAL (UNIPOLAR) LEADS | 179 | ||
| Right-Sided Chest Leads | 179 | ||
| Facing Leads | 179 | ||
| ELECTRICAL CURRENT | 179 | ||
| ELECTRICAL AXIS AND VECTORS | 183 | ||
| HEXAXIAL REFERENCE FIGURE | 186 | ||
| The QRS Axis | 187 | ||
| DETERMINING THE QRS AXIS | 189 | ||
| Rapid Method | 189 | ||
| Accurate Measurement | 189 | ||
| Step 1 | 189 | ||
| Step 2 | 193 | ||
| Step 3 | 194 | ||
| TAKE-HOME POINTS | 195 | ||
| 13 - Bundle Branch and\rFascicular Blocks | 197 | ||
| ANATOMY AND PHYSIOLOGY OF THE BUNDLE BRANCH\rCONDUCTION SYSTEM | 197 | ||
| Anatomy | 197 | ||
| BLOOD SUPPLY | 197 | ||
| RIGHT BUNDLE BRANCH BLOCK | 199 | ||
| Characteristics | 201 | ||
| Duration. Greater than 0.12 second; 0.10 to 0.12 second in incomplete RBBB. VAT exceeds 0.035 second in leads V1 and V2 | 201 | ||
| Axis. May be normal or have a slight right axis deviation (between +90° and 110°). This shift to the right occurs because left v... | 201 | ||
| Ventricular activation time. Greater than 0.035 second (1 small box) in the precordial leads V1 and V2 | 201 | ||
| PATTERN | 201 | ||
| Q wave. Normal small septal q waves may be present in leads I, aVL, and V5 to V6, reflecting the normal depolarization of the in... | 201 | ||
| R wave. Small r waves are present in the right precordial leads V1 to V2, reflecting the normal depolarization of the interventr... | 201 | ||
| S wave. Deep and slurred S waves are present in leads I and aVL and the left precordial leads V5 to V6. This produces the typica... | 201 | ||
| ST SEGMENT | 201 | ||
| T WAVE | 201 | ||
| Causes | 202 | ||
| Clinical Significance | 202 | ||
| Treatment | 202 | ||
| LEFT BUNDLE BRANCH BLOCK | 203 | ||
| Characteristics | 203 | ||
| Duration. Greater than 0.12 second; 0.10 to 0.12 second in incomplete LBBB. VAT exceeds 0.035 second in leads V1 and V2 | 203 | ||
| Pattern. In LBBB, depolarization of the left ventricle occurs much later than the right ventricle. The impulses of depolarizatio... | 203 | ||
| Q wave. Septal q waves are absent in leads I and aVL and in the left precordial leads (V5 to V6), where they normally occur. The... | 203 | ||
| R wave. Small, narrow r (small r) waves are present in leads V1 to V3 when the interventricular septum depolarizes from right to... | 203 | ||
| S wave. Deep, wide S waves are present in leads V1 to V3, producing the typical rS or QS complexes. Because of these wide S wave... | 203 | ||
| ST SEGMENT | 203 | ||
| T WAVE | 203 | ||
| Causes | 203 | ||
| Clinical Significance | 204 | ||
| Treatment | 204 | ||
| HEMIBLOCK | 204 | ||
| LEFT ANTERIOR FASCICULAR BLOCK (LEFT ANTERIOR HEMIBLOCK) | 205 | ||
| Characteristics | 205 | ||
| Duration. Normal; less than 0.12 second in duration | 205 | ||
| Axis. Left axis deviation (–30° to –90°) caused by the delayed depolarization of the anterior and lateral walls of the left vent... | 205 | ||
| Pattern. Appears normal, without unusual notching or any delay in the VAT. The presence of an initial small q wave in lead I cou... | 205 | ||
| Q wave. Initial small q waves are present in leads I and aVL | 205 | ||
| R wave. Initial small r waves are present in leads II, III, and aVF | 205 | ||
| S wave. Usually deep; larger than the R waves in leads II, III, and aVF | 205 | ||
| ST SEGMENT | 205 | ||
| T WAVE | 205 | ||
| Causes | 205 | ||
| Characteristics | 206 | ||
| Duration. Normal (less than 0.12 second) | 206 | ||
| Axis. Right axis deviation (+90° to +180°) | 206 | ||
| Pattern. The QRS complexes appear normal without unusual notching or any delay in the VAT. The presence of an initial small q wa... | 206 | ||
| Q wave. Initial small q waves are present in leads II, III, and aVF and absent in leads I, aVL, and V5 to V6 | 206 | ||
| R wave. Initial small r waves are present in leads I and aVL, and tall R waves are present in leads II, III, and aVF | 206 | ||
| S wave. Deep S waves are present in leads I and aVL | 206 | ||
| ST SEGMENT | 206 | ||
| T WAVE | 206 | ||
| Causes | 206 | ||
| BIFASCICULAR BLOCK | 207 | ||
| NONSPECIFIC INTRAVENTRICULAR CONDUCTION DELAY | 209 | ||
| DIFFERENTIATING BETWEEN SVT AND VT | 209 | ||
| TAKE-HOME POINTS | 209 | ||
| 14 - Hypertrophy, Electrolytes, and Other ECG Findings | 212 | ||
| ART CHAMBER ENLARGEMENT | 212 | ||
| DISTENTION | 212 | ||
| HYPERTROPHY | 212 | ||
| RIGHT ATRIAL ENLARGEMENT | 213 | ||
| Characteristics (Fig. 14.1) | 213 | ||
| 15 - Coronary Heart Disease and the 12-Lead ECG | 233 | ||
| CORONARY CIRCULATION | 233 | ||
| Left Coronary Artery | 233 | ||
| CORONARY HEART DISEASE | 234 | ||
| Coronary Atherosclerosis and Thrombosis | 235 | ||
| Stable, Vulnerable, and Unstable Plaques | 236 | ||
| Plaque Erosion and Rupture | 237 | ||
| THROMBUS FORMATION AND LYSIS | 237 | ||
| Blood Components | 237 | ||
| PLATELETS | 237 | ||
| PROTHROMBIN | 238 | ||
| FIBRINOGEN | 238 | ||
| PLASMINOGEN | 238 | ||
| Tissue Components | 238 | ||
| VON WILLEBRAND FACTOR | 238 | ||
| COLLAGEN FIBERS | 238 | ||
| TISSUE FACTOR | 238 | ||
| TISSUE PLASMINOGEN ACTIVATOR | 239 | ||
| Phases of Thrombus Formation | 239 | ||
| PHASE 1: SUBENDOTHELIAL EXPOSURE AND VASOCONSTRICTION | 239 | ||
| PHASE 2: PLATELET ADHESION AND ACTIVATION | 239 | ||
| PHASE 3: PLATELET AGGREGATION | 239 | ||
| PHASE 4: THROMBUS FORMATION | 239 | ||
| Phases of Thrombolysis | 239 | ||
| PHASE 1: ACTIVATION OF INTRINSIC AND EXTRINSIC PATHWAYS | 239 | ||
| PHASE 2: PLASMIN FORMATION | 239 | ||
| PHASE 3: FIBRINOLYSIS | 239 | ||
| MYOCARDIAL ISCHEMIA, INJURY, AND INFARCTION | 239 | ||
| Ischemia | 239 | ||
| Injury | 239 | ||
| Infarction | 241 | ||
| Categorization of Causes | 241 | ||
| TYPE 1 | 241 | ||
| TYPE 2 | 241 | ||
| TYPE 3 | 241 | ||
| TYPES 4 AND 5 | 241 | ||
| PATHOPHYSIOLOGY OF MYOCARDIAL INFARCTION | 241 | ||
| PHASE 1 | 242 | ||
| PHASE 2 | 243 | ||
| PHASE 3 | 243 | ||
| PHASE 4 | 243 | ||
| Anatomic Locations of Myocardial Infarction | 243 | ||
| ECG Changes in Myocardial Infarction | 243 | ||
| T WAVE | 247 | ||
| ST SEGMENT | 248 | ||
| ST elevation. ST segment elevation is an ECG sign of severe, extensive, transmural, myocardial ischemia and injury in the evolut... | 248 | ||
| ST depression. ST segment depression is an ECG sign of subendocardial ischemia and injury. Similar to the criteria for ST elevat... | 248 | ||
| Q WAVE | 249 | ||
| Physiologic Q wave. A physiologic Q wave is the result of the normal depolarization of the interventricular septum from left to ... | 249 | ||
| Pathologic Q wave. A Q wave produced by irreversible myocardial necrosis after an MI is referred to as a pathologic Q wave. It i... | 249 | ||
| Determining the site of a Q wave myocardial infarction. The location of an acute Q wave MI is determined by the facing leads in ... | 250 | ||
| TAKE-HOME POINTS | 253 | ||
| 16 - ECG Diagnosis of Myocardial Infarction | 256 | ||
| SEPTAL MYOCARDIAL INFARCTION | 256 | ||
| Coronary Arteries Involved and Site of Occlusion | 256 | ||
| Location of Infarct | 256 | ||
| ECG Changes | 257 | ||
| 17 - Diagnosis and Treatment of Acute Coronary Syndrome | 276 | ||
| PRESENTATION OF MYOCARDIAL INFARCTION | 276 | ||
| Sex- and Age-Related Differences | 276 | ||
| Diabetes Mellitus | 276 | ||
| HISTORY TAKING IN SUSPECTED ACUTE CORONARY SYNDROME | 276 | ||
| Chief Complaint | 277 | ||
| Past Medical History | 277 | ||
| HYPERTENSION | 277 | ||
| POSSIBILITY OF AORTIC DISSECTION | 277 | ||
| RISK OF BLEEDING | 277 | ||
| SIGNS AND SYMPTOMS OF ACUTE CORONARY SYNDROME | 278 | ||
| Symptoms | 278 | ||
| GENERAL AND NEUROLOGIC SYMPTOMS | 278 | ||
| CARDIOVASCULAR SYMPTOMS | 278 | ||
| Stable Angina | 279 | ||
| Unstable Angina | 279 | ||
| Palpitations. A regular heartbeat interrupted by one or more premature contractions is a common cardiac irregularity present in ... | 280 | ||
| RESPIRATORY SYMPTOMS | 280 | ||
| Dyspnea. Dyspnea—that is, shortness of breath or difficulty breathing—is often seen in ACS. It may appear gradually or suddenly.... | 280 | ||
| Cough. Cough accompanied by sputum, a productive cough, is a symptom in patients with pulmonary edema associated with left heart... | 280 | ||
| Wheezing. Wheezing may accompany a patient’s cough. This is particularly true in those with a coexisting history of chronic obst... | 280 | ||
| GASTROINTESTINAL SYMPTOMS | 280 | ||
| Signs | 280 | ||
| GENERAL APPEARANCE AND NEUROLOGIC SIGNS | 280 | ||
| VITAL SIGNS | 280 | ||
| Pulse rate. The pulse rate is usually normal (60 to 100 beats/min), but may be rapid (>100 beats/min [tachycardia]) because of t... | 280 | ||
| Pulse rhythm. The rhythm of the pulse may be regular or irregular. In a small percentage of patients, an irregular pulse caused ... | 281 | ||
| Respiration. Respiration in ACS may vary, depending on the presence or absence of anxiety, heart failure, hypoxia, hypotension, ... | 281 | ||
| APPEARANCE OF THE SKIN | 281 | ||
| APPEARANCE OF THE VEINS | 281 | ||
| CARDIOVASCULAR SIGNS | 281 | ||
| Breath sounds. The breath sounds produced by the flow of air through the air passages may be normal, labored and noisy, decrease... | 281 | ||
| Rales, rhonchi, and wheezes. The passage of air through bronchi and bronchioles narrowed by edema and spasm and filled with flui... | 282 | ||
| Consolidation and pleural effusion. When a segment of the lung becomes completely filled with fluid, preventing air from enterin... | 282 | ||
| APPEARANCE OF BODY TISSUES | 282 | ||
| MANAGEMENT OF ACUTE CORONARY SYNDROME | 282 | ||
| GOALS OF MANAGEMENT | 282 | ||
| Emergency Department Management | 286 | ||
| RISK ASSESSMENT | 286 | ||
| DIAGNOSIS | 286 | ||
| 12-Lead ECG. Patients whose complaints suggest ACS should be taken immediately into an examining room for evaluation. The goal i... | 286 | ||
| Cardiac biomarkers. Upon admission to the ED, blood studies are routinely performed to determine whether certain proteins and en... | 288 | ||
| Creatinine Kinase | 288 | ||
| Cardiac Troponin T and Troponin I (cTnT, cTnl) | 288 | ||
| DETERMINATION OF APPROPRIATE THERAPY | 288 | ||
| MANAGEMENT OF SPECIFIC\rCONDITIONS | 289 | ||
| Step One | 290 | ||
| Step Two | 291 | ||
| OPTION 1 | 291 | ||
| OPTION 2 | 291 | ||
| TAKE-HOME POINTS | 292 | ||
| A - Methods of Determining the QRS Axis | 295 | ||
| METHOD A: THE TWO-LEAD METHOD | 295 | ||
| METHOD B: THE THREE-LEAD METHOD | 296 | ||
| METHOD C: THE FOUR-LEAD METHOD | 298 | ||
| METHOD D: THE SIX-LEAD METHOD | 300 | ||
| Step 1. Determine the quadrant in which the QRS axis lies | 300 | ||
| Step 2. Determine the placement of the QRS axis in the quadrant in which it lies to within a 30° arc | 302 | ||
| METHOD E: THE “PERPENDICULAR” METHOD | 306 | ||
| Step 1 | 306 | ||
| Step 2 | 307 | ||
| Step 3 | 307 | ||
| Step 4 | 307 | ||
| B - ANSWERS TO CHAPTER REVIEW QUESTIONS | 308 | ||
| CHAPTER 1 | 308 | ||
| CHAPTER 2 | 308 | ||
| CHAPTER 3 | 309 | ||
| CHAPTER 4 | 309 | ||
| CHAPTER 5 | 309 | ||
| CHAPTER 6 | 310 | ||
| CHAPTER 7 | 310 | ||
| CHAPTER 8 | 310 | ||
| CHAPTER 9 | 311 | ||
| CHAPTER 10 | 311 | ||
| CHAPTER 11 | 312 | ||
| CHAPTER 12 | 312 | ||
| CHAPTER 13 | 313 | ||
| CHAPTER 14 | 313 | ||
| CHAPTER 15 | 313 | ||
| CHAPTER 16 | 314 | ||
| CHAPTER 17 | 314 | ||
| C - RHYTHM INTERPRETATION: SELF-ASSESSMENT | 315 | ||
| DYSRHYTHMIAS | 315 | ||
| II. BUNDLE BRANCH AND FASCICULAR BLOCKS | 359 | ||
| III. MYOCARDIAL INFARCTIONS | 361 | ||
| IV. QRS AXES | 370 | ||
| V. ECG CHANGES: DRUG AND ELECTROLYTE | 371 | ||
| VI. ECG CHANGES: MISCELLANEOUS | 372 | ||
| VII. SCENARIOS | 376 | ||
| Scenario 1 | 376 | ||
| Scenario 2 | 377 | ||
| Scenario 3 | 377 | ||
| Scenario 4 | 378 | ||
| Scenario 5 | 378 | ||
| Scenario 6 | 379 | ||
| Scenario 7 | 379 | ||
| Scenario 8 | 380 | ||
| Scenario 9 | 381 | ||
| Scenario 10 | 382 | ||
| D - SELF-ASSESSMENT ANSWER KEY* | 383 | ||
| I. DYSRHYTHMIAS | 383 | ||
| II. BUNDLE BRANCH AND\rFASCICULAR BLOCKS | 398 | ||
| III. MYOCARDIAL INFARCTIONS | 398 | ||
| IV. QRS AXES | 398 | ||
| V. ECG CHANGES: DRUG AND ELECTROLYTE | 398 | ||
| VI. ECG CHANGES: MISCELLANEOUS | 398 | ||
| VII. SCENARIOS | 398 | ||
| Scenario 1 | 398 | ||
| Scenario 2 | 398 | ||
| Scenario 3 | 399 | ||
| Scenario 4 | 399 | ||
| Scenario 5 | 399 | ||
| Scenario 6 | 399 | ||
| Scenario 7 | 399 | ||
| Scenario 8 | 400 | ||
| Scenario 9 | 400 | ||
| Scenario 10 | 400 | ||
| GLOSSARY | 401 | ||
| INDEX | 427 | ||
| A | 427 | ||
| B | 429 | ||
| C | 430 | ||
| D | 431 | ||
| E | 432 | ||
| F | 433 | ||
| G | 433 | ||
| H | 433 | ||
| I | 434 | ||
| J | 434 | ||
| L | 435 | ||
| M | 435 | ||
| N | 436 | ||
| O | 436 | ||
| P | 436 | ||
| Q | 438 | ||
| R | 439 | ||
| S | 440 | ||
| T | 442 | ||
| U | 443 | ||
| V | 443 | ||
| W | 443 | ||
| Z | 444 |