Table Of ContentABC OF
CLINICAL ELECTRO-
CARDIOGRAPHY
FRANCIS MORRIS
JUNE EDHOUSE
WILLIAM J BRADY
JOHN CAMM
BMJ Books
ABC OF
CLINICAL ELECTROCARDIOGRAPHY
ABC OF
CLINICAL ELECTROCARDIOGRAPHY
Edited by
FRANCIS MORRIS
Consultant in Emergency Medicine, Northern General Hospital, Sheffield
JUNE EDHOUSE
Consultant in Emergency Medicine, Stepping Hill Hospital, Stockport
WILLIAM J BRADY
Associate Professor, Programme Director, and Vice Chair, Department of Emergency
Medicine, University of Virginia, Charlottesville, VA, USA
and
JOHN CAMM
Professor of Clinical Cardiology, St George’s Hospital Medical School, London
© BMJ Publishing Group 2003
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system,
or transmitted, in any form or by any means, electronic, mechanical, photocopying,
recording and/or otherwise, without the prior written permission of the publishers.
First published in 2003
by BMJ Books, BMA House, Tavistock Square,
London WC1H 9JR
www.bmjbooks.com
British Library Cataloguing in Publication Data
A catalogue record for this book is available from the British Library
ISBN 0 7279 1536 3
Typeset by BMJ Electronic Production
Printed and bound in Spain by GraphyCems, Navarra
Cover image depicts a chest x ray and electrocardiogram trace
Composite image of an electrocardiogram trace showing termination of atrioventricular nodal
re-entrant tachycardia, overlaid onto a false-coloured chest x ray
With permission from Sheila Terry/Science Photo Library
v
Contents
Contributors
vi
Preface
vii
1
Introduction. I—Leads, rate, rhythm, and cardiac axis
1
Steve Meek, Francis Morris
2
Introduction. II—Basic terminology
5
Steve Meek, Francis Morris
3
Bradycardias and atrioventricular conduction block
9
David Da Costa, William J Brady, June Edhouse
4
Atrial arrhythmias
13
Steve Goodacre, Richard Irons
5
Junctional tachycardias
17
Demas Esberger, Sallyann Jones, Francis Morris
6
Broad complex tachycardia—Part I
21
June Edhouse, Francis Morris
7
Broad complex tachycardia—Part II
25
June Edhouse, Francis Morris
8
Acute myocardial infarction—Part I
29
Francis Morris, William J Brady
9
Acute myocardial infarction—Part II
33
June Edhouse, William J Brady, Francis Morris
10
Myocardial ischaemia
37
Kevin Channer, Francis Morris
11
Exercise tolerance testing
41
Jonathan Hill, Adam Timmis
12
Conditions affecting the right side of the heart
45
Richard A Harrigan, Kevin Jones
13
Conditions affecting the left side of the heart
49
June Edhouse, R K Thakur, Jihad M Khalil
14
Conditions not primarily affecting the heart
53
Corey Slovis, Richard Jenkins
15
Paediatric electrocardiography
57
Steve Goodacre, Karen McLeod
16
Cardiac arrest rhythms
61
Robert French, Daniel DeBehnke, Stephen Hawes
17
Pacemakers and electrocardiography
66
Richard Harper, Francis Morris
18
Pericarditis, myocarditis, drug effects, and congenital heart disease
70
Chris A Ghammaghami, Jennifer H Lindsey
Index
75
William J Brady
Associate Professor, Programme Director, and Vice Chair,
Department of Emergency Medicine, University of Virginia,
Charlottesville, VA, USA
Kevin Channer
Consultant Cardiologist, Royal Hallamshire Hospital, Sheffield
David Da Costa
Consultant Physician, Northern General Hospital, Sheffield
Daniel De Behnke
Department of Emergency Medicine, Medical College of
Wisconsin, Milwaukee, WI, USA
June Edhouse
Consultant in Emergency Medicine, Stepping Hill Hospital,
Stockport
Demas Esberger
Consultant in Accident and Emergency Medicine, Queen’s
Medical Centre, Nottingham
Robert French
Department of Emergency Medicine, Medical College of
Wisconsin, Milwaukee, WI, USA
Chris A Ghammaghami
Assistant Professor of Emergency and Internal Medicine,
Director, Chest Pain Centre, Department of Emergency
Medicine, University of Virginia Health System, Charlottesville,
VA, USA
Steve Goodacre
Health Services Research Fellow, Accident and Emergency
Department, Northern General Hospital, Sheffield
Richard Harper
Assistant Professor, Department of Emergency Medicine,
Oregon Health and Science University, Portland,
Oregon, USA
Richard A Harrigan
Associate Professor of Emergency Medicine, Temple University
School of Medicine, Associate Research Director, Division of
Emergency Medicine, Temple University Hospital,
Philadelphia, PA, USA
Stephen Hawes
Department of Emergency Medicine, Wythenshaw Hospital,
Manchester
Jonathan Hill
Specialist Registrar in Cardiology, Barts and the London
NHS Trust
Richard Irons
Consultant in Accident and Emergency Medicine, Princess of
Wales Hospital, Bridgend
Richard Jenkins
Specialist Registrar in General Medicine and Endocrinology,
Northern General Hospital, Sheffield
Kevin Jones
Consultant Chest Physician, Bolton Royal Hospital
Sallyann Jones
Specialist Registrar in Accident and Emergency Medicine,
Queen’s Medical Centre, Nottingham
Jihad M Khalil
Thoracic and Cardiovascular Institute, Michigan State
University, Lancing, MI, USA
Jennifer H Lindsey
Fellow, Division of Cardiology, Department of Pediatrics,
University of Virginia Health System, Charlottesville, VA, USA
Karen McLeod
Consultant Paediatric Cardiologist, Royal Hospital for
Sick Children, Glasgow
Steve Meek
Consultant in Emergency Medicine, Royal United Hospitals,
Bath
Francis Morris
Consultant in Emergency Medicine, Northern General
Hospital, Sheffield
Corey Slovis
Professor of Emergency Medicine and Medicine, Vanderbilt
University Medical Center, Department of Emergency
Medicine, Nashville, TN, USA
R K Thakur
Professor of Medicine, Thoracic and Cardiovascular Institute,
Michigan State University, Lancing, MI, USA
Adam Timmis
Consultant Cardiologist, London Chest Hospital, Barts and the
London NHS Trust
vi
Contributors
vii
Preface
To my mind electrocardiogram interpretation is all about pattern recognition. This collection of 18 articles covers all the important
patterns encountered in emergency medicine. Whether you are a novice or an experienced clinician, I hope that you find this book
enjoyable and clinically relevant.
Francis Morris
Sheffield 2002
1
Introduction. I—Leads, rate, rhythm, and cardiac axis
Steve Meek, Francis Morris
Electrocardiography is a fundamental part of cardiovascular
assessment. It is an essential tool for investigating cardiac
arrhythmias and is also useful in diagnosing cardiac disorders
such as myocardial infarction. Familiarity with the wide range of
patterns seen in the electrocardiograms of normal subjects and
an understanding of the effects of non-cardiac disorders on the
trace are prerequisites to accurate interpretation.
The contraction and relaxation of cardiac muscle results
from the depolarisation and repolarisation of myocardial cells.
These electrical changes are recorded via electrodes placed on
the limbs and chest wall and are transcribed on to graph paper
to produce an electrocardiogram (commonly known as an
ECG).
The sinoatrial node acts as a natural pacemaker and initiates
atrial depolarisation. The impulse is propagated to the
ventricles by the atrioventricular node and spreads in a
coordinated fashion throughout the ventricles via the
specialised conducting tissue of the His-Purkinje system. Thus,
after delay in the atrioventricular mode, atrial contraction is
followed by rapid and coordinated contraction of the ventricles.
The electrocardiogram is recorded on to standard paper
travelling at a rate of 25 mm/s. The paper is divided into large
squares, each measuring 5 mm wide and equivalent to 0.2 s.
Each large square is five small squares in width, and each small
square is 1 mm wide and equivalent to 0.04 s.
The electrical activity detected by the electrocardiogram
machine is measured in millivolts. Machines are calibrated so
that a signal with an amplitude of 1 mV moves the recording
stylus vertically 1 cm. Throughout this text, the amplitude of
waveforms will be expressed as: 0.1 mV = 1 mm = 1 small
square.
The amplitude of the waveform recorded in any lead may
be influenced by the myocardial mass, the net vector of
depolarisation, the thickness and properties of the intervening
tissues, and the distance between the electrode and the
myocardium. Patients with ventricular hypertrophy have a
relatively large myocardial mass and are therefore likely to have
high amplitude waveforms. In the presence of pericardial fluid,
pulmonary emphysema, or obesity, there is increased resistance
to current flow, and thus waveform amplitude is reduced.
The direction of the deflection on the electrocardiogram
depends on whether the electrical impulse is travelling towards
or away from a detecting electrode. By convention, an electrical
impulse travelling directly towards the electrode produces an
upright (“positive”) deflection relative to the isoelectric baseline,
whereas an impulse moving directly away from an electrode
produces a downward (“negative”) deflection relative to the
Throughout this article the duration of
waveforms will be expressed as
0.04 s = 1 mm = 1 small square
Sinoatrial node
Electrically inert
atrioventricular
region
Left bundle branch
Left anterior
hemifascicle
Left posterior
hemifascicle
Right
atrium
Left
atrium
Right
ventricle
Left
ventricle
Atrioventricular node
Right bundle branch
The His-Purkinje conduction system
V5
V5
Role of body habitus and disease on the amplitude of the QRS complex.
Top: Low amplitude complexes in an obese woman with hypothyroidism.
Bottom: High amplitude complexes in a hypertensive man
Speed : 25 mm/s
Gain : 10 mm/mV
Standard calibration signal
1
