Arrhythmia Essentials

431 Pages·2016·11.919 MB·English

by  Brian Olshansky, Mina K Chung, Steven M Pogwizd and Nora Goldschlager (Auth.)

ES2
SECOND EDITION
ARRHYTHMIA
ESSENTIALS
Brian Olshansky, MD
Professor Emeritus of Medicine
University of Iowa Hospitals
Iowa City, Iowa
Cardiac Electrophysiologist
Mercy Hospital, North Iowa
Mason City, Iowa
Mina K. Chung, MD
Professor of Medicine
Cleveland Clinic Lerner College of Medicine
Case Western Reserve University
Cardiac Electrophysiology and Pacing
Department of Cardiovascular Medicine, Heart and Vascular Institute
Department of Molecular Cardiology, Lerner Research Institute
Cleveland Clinic
Cleveland, Ohio
Steven M. Pogwizd, MD
Featheringill Endowed Professor
in Cardiac Arrhythmia Research
Professor of Medicine, Physiology and Biophysics, and
Biomedical Engineering
Director, Center for Cardiovascular Biology
Associate Director, Cardiac Rhythm Management Laboratory
University of Alabama at Birmingham
Birmingham, Alabama
Nora Goldschlager, MD
Professor of Clinical Medicine
University of California, San Francisco
Chief, Clinical Cardiology
Director, Coronary Care Unit
ECG Laboratory and Pacemaker Clinic
San Francisco General Hospital
San Francisco, California
1600 John F. Kennedy Blvd.
Ste 1800
Philadelphia, PA 19103-2899
ARRHYTHMIA ESSENTIALS, SECOND EDITION ISBN: 978-0-323-39968-5
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Notices
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Previous edition copyrighted 2012 by Jones & Bartlett Learning, LLC.
Library of Congress Cataloging-in-Publication Data
Names: Olshansky, Brian, author. | Chung, Mina K., author. | Pogwizd, Steven
M., 1955- author. | Goldschlager, Nora, author.
Title: Arrhythmia essentials / Brian Olshansky, Mina K. Chung, Steven M.
Pogwizd, Nora Goldschlager.
Description: Second edition. | Philadelphia, PA : Elsevier, [2017] | Preceded
by: Arrhythmia essentials / Brian Olshansky … [et al.]. c2012. |
Includes bibliographical references and index.
Identifiers: LCCN 2016038912 | ISBN 9780323399685 (alk. paper)
Subjects: | MESH: Arrhythmias, Cardiac
Classification: LCC RC685.A65 | NLM WG 330 | DDC 616.1/28–dc23 LC record
available at https://lccn.loc.gov/2016038912
Content Strategist: Maureen Iannuzzi
Content Development Specialist: Stacy Eastman
Publishing Services Manager: Patricia Tannian
Senior Project Manager: Cindy Thoms
Designer: Miles Hitchen
Printed in United States of America
Last digit is the print number: 9 8 7 6 5 4 3 2 1
Foreword
I very much enjoyed reading this text as it represents a tour de force by a
group of eminent clinicians and scientists focused on the diagnoses and
treatment of cardiac rhythm disorders. The strong points are the beautiful
and clear illustrative ECG material together with a methodical and yet
practical approach to diagnoses and treatment. The authors are to be
applauded for very up-to-date treatment algorithms for a wide variety of
arrhythmic disorders, including the genetic arrhythmia syndromes.
This book is easily portable and is of great value for the busy clinician
called upon to treat these patients, as well as students and nurses
interested in learning more about this rapidly expanding area in medicine.
It should also prove of great value to seasoned clinicians eager to gain an
authoritative review of the management and treatment of patients with
cardiac rhythm disorders.
Melvin Scheinman, MD, FACC
Professor of Medicine
Walter H. Shorenstein Endowed Chair in Cardiology
Chief of Cardiology Genetics Arrhythmia Program
University of California, San Francisco
San Francisco, California
iii
Preface
Arrhythmia Essentials is a comprehensive, yet practical handbook that
provides an approach to patients who have cardiac arrhythmias, including
those arrhythmias that occur in specific clinical settings. The book is
meant to be used to help assess and manage patients with virtually all
arrhythmias and related symptoms and includes treatment strategies
that may be considered. To this end, we have focused on a step-by-step
approach for ease of use. The book is divided into chapters that include
sinus node function, bradycardias, tachycardias, heart block, normal and
abnormal pacemaker and implantable defibrillator function, and special
arrhythmia-related topics such as syncope, palpitations, arrhythmias in
the athlete, and other clinical conditions of importance. Also provided is
a section that summarizes available drugs useful to treat patients with
cardiac arrhythmias. The second edition includes a brand new chapter
on managing arrhythmias in pregnancy. Each chapter is accompanied by
illustrative electrocardiograms and, where thought to be useful, practical
algorithms that help delineate an organized approach to arrhythmia
diagnosis and management.
This is the first practical handbook written on this topic that is aimed
at practicing clinicians of all specialties, that is based on a contemporary
approach, and that focuses on new and advanced therapeutic options and
technologies. We believe that the reader will refer to this book often and
find it to be compelling, concise, comprehensive, and relevant. It is hoped
that this book (in print or on a smartphone or tablet) will find its way to a
lab coat pocket, and be available on patient care units rather than sit on
the library bookshelf.
Brian Olshansky, MD
Mina K. Chung, MD
Steven M. Pogwizd, MD
Nora Goldschlager, MD
iv
Chapter 1
Sinus Node: Normal and
Abnormal Rhythms
NORMAL SINUS NODE
Description
Normal sinus rhythm (NSR) is an atrial rhythm caused by electrical
activation that originates from the sinus node, a structure located in the
area of the junction of the right atrium and superior vena cava. NSR
P waves, representing atrial depolarization (but not sinus node activity
itself), are upright in leads I and aVL and the inferior leads (II, III, aVF),
indicating the high to low atrial activation pattern (Fig. 1.1). The P wave
in leads V -V may be upright, biphasic, or slightly inverted, whereas
1 2
the P waves in leads V -V tend to be upright, indicating right to left
3 6
atrial activation. The P-wave morphology may change with alterations in
autonomic tone, heart rate, and atrial abnormalities such as hypertrophy.
High vagal tone can be associated with a more inferior exit of the impulse
from the sinus node, whereas high sympathetic tone can be associated
with a more superior exit from the node.
Clinical Symptoms and Presentations
NSR is generally considered to have a rate of 60 to 100 beats per minute
(bpm), although 50 bpm is still normal. Rate changes with alterations in
autonomic tone; at rest, most individuals have their heart rate regulated by
the vagus nerve.
Individuals with high vagal tone (such as those who are in excellent
physical condition) may exhibit sinus arrhythmia, a normal rhythm in which
the rate varies with respiration (Fig. 1.2). In sinus arrhythmia, inspiration
increases the rate and expiration decreases the rate. Sinus arrhythmia
is common during sleep and in patients with obstructive sleep apnea, in
which the decrease in rate can be substantial.
Various forms of sinus arrhythmia exist, including a non–respiration-
dependent form that may indicate sinus node dysfunction (SND).
Ventriculophasic sinus arrhythmia is present when alterations in the
sinus rate are due to atrioventricular (AV) block: The P-P intervals enclosing
a QRS complex are shorter than P-P intervals not enclosing a QRS
complex.
A change in sinus rate can be gradual or abrupt and can occur with
change in body position and exercise. Patients who are in good physical
condition generally have more gradual acceleration in sinus rate with
exercise and a rapid slowing of the sinus rate at the end of exercise,
1
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FIGURE 1.1
Normal sinus rhythm. Normal sinus rhythm is characterized by P waves that are usually upright in leads I, aVL, II, III, aVF, and V3-V6
at a rate between 60 and 100 bpm.
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Normal sinus rhythm with sinus arrhythmia. This lead V1 and II rhythm strip shows normal sinus rhythm with sinus arrhythmia, in which the P-P intervals Ab
vary by greater than 0.16 seconds. Sinus arrhythmia is often related to respiratory cycles. n
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4 Chapter 1 Sinus Node: Normal and Abnormal Rhythms
compared with less physically fit individuals or individuals with heart
disease. Higher resting sinus rates have been associated with increased
risk for overall mortality.
Wandering atrial pacemaker (WAP) (Fig. 1.3) occurs in association with
high vagal tone and is a benign rhythm. In WAP, there are varying exit
points of the sinus impulse from the sinus node or impulses that originate
from the sinus node and wander from the node to the low atrium and back.
WAP is often seen in patients with sinus arrhythmia. WAP should not be
confused with “multifocal atrial rhythm” (see Fig. 3.13).
Approach to Management
Although sinus rhythm generally does not require any treatment, an
inability to increase the sinus rate appropriately in response to increases in
metabolic needs (“chronotropic incompetence”) may require permanent
rate responsive cardiac pacing when it is documented to cause symptoms.
Definitions of chronotropic incompetence are many and varied, and there
is no general agreement as to its parameters.
SINUS NODE DYSFUNCTION, INCLUDING SINUS BRADYCARDIA
AND TACHYCARDIA-BRADYCARDIA SYNDROME
Description
Sinus bradycardia (SB) (Fig. 1.4) is generally defined as sinus rates of less
than 60 bpm, although 50 bpm is likely within the normal range of rate.
SB is often a normal finding in young, healthy adults, especially in athletes
with high vagal tone. SB frequently occurs at rest and during sleep. In
trained athletes or individuals with high vagal tone, sinus rates in the 40s
and even at times in the 30s, especially during sleep, are not uncommon.
SB may be associated with a narrow QRS complex or, in the presence of
bundle branch block (BBB) or intraventricular conduction delay, with a
wide QRS complex (Fig. 1.5).
The sinus rate normally slows with age. SND from sinus node
degeneration is more frequent in older persons. SND, sometimes termed
“sick sinus syndrome,” is a very common arrhythmia and includes sinus
pauses, sinus arrest, inappropriate SB, chronotropic incompetence,
sinoatrial (SA) exit block, combinations of SA and AV conduction
abnormalities, and tachycardia-bradycardia (tachy-brady) syndrome
(e.g., paroxysmal or persistent atrial tachyarrhythmias with periods of
bradycardia or postconversion sinus pauses) (Fig. 1.6).
Associated Conditions
SB is often associated with sinus arrhythmia, escape rhythms (junctional
and ventricular), accelerated rhythms (junctional and ventricular), atrial
arrhythmias, WAP, or SA or AV Wenckebach-like periods. SB is usually
benign but can be associated with certain conditions and diseases,
including hypothyroidism, vagal stimulation, carotid sinus hypersensitivity,
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FIGURE 1.3 b
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mWaonrpdheorilnogg iaetsr.ial pacemaker. This lead V1 II, and V5 rhythm strip shows wandering atrial pacemaker. There are at least three P wave orm
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5