P P P P P P
Supraventricular RhythmsSinus Rhythms Conduction Defects
Cardiac Conduction System
Sinoatrial
Node
Right Bundle
Branch
LEFT
ATRIUM
HIS Bundle
Left Bundle
Branch
RIGHT ATRI-
UM
RIGHT
VENTRICLE
LEFT
VENTRICLE
ECG Components Electrical and Mechanical Events
HORIZONTAL
AXIS
1 Small Square = .04 sec (40 msec)
1 Large Square = .2 sec (200 msec)
5 Large Squares = 1 sec (1000 msec)
VERTICAL
AXIS
1 Small Square = 1 mm (0.1 mV)
1 Large Square = 5 mm (0.5 mV)
2 Large Squares = 1 mV
This is part one of two posters to assist healthcare professionals in
recognizing basic arrhythmias. According to the Practice Standards
for Electrocardiographic Monitoring in Hospital Settings (Circulation.
2004;110:2721-2746) in general, the mechanisms of arrhythmias are
the same in both adults and children. However, the ECG appearance of
the arrhythmias may differ due to developmental issues such as heart
size, baseline heart rate, sinus and AV node function, and automatic
innervation.
ECG terminology and diagnostic criteria often vary from text to text and
from one teacher to another. There are often several terms describing
similar findings (for example: Premature Atrial Contraction, Atrial
Premature Complex, Atrial Extrasystole, Supraventricular Ectopic Beat,
etc.) It is important to correlate the ECG interpretation with the clinical
observation of the patient.
Arrhythmia Recognition (poster 1 of 2) This poster includes Premature Ventricular Conduction, Pacemaker Lead
Placement, ST Segment Depression, Ventricular Rhythms, Pacemaker
Rhythms, Full Compensatory Pause and ECG Artifact. The ECG rhythm
strips display lead II as the top waveform and lead V1 as the bottom
waveform. Classic examples are shown for each rhythm to provide basic
visualization and avoid complexities. The intended use of this poster is
to compliment a text and/or course — in addition to a reference guide for
arrhythmia recognition
The most common ECG rate, interval, and duration measurements are from the following publications:
• Clinical Electrocardiography (Post Graduate Institute for Medicine).
• Understanding Electrocardiography (Mary Boudreau Conover).
• How to Quickly and Accurately Master Arrhythmia Interpretation (Dale Davis).
• Principles of Clinical Electrocardiography (M. J. Goldman).
• Basic Dysrhythmias Interpretation and Management (Robert Huszar).
• An Introduction to Electrocardiography (Leo Shamroth).
• Interpretation of Arrhythmias (Emanual Stein).
All values 2nd – 98th percentile; numbers in parentheses, means. Adapted from Pediatr Cardiol. 1979;1:123.
Normal ECG Standards for Children by Age
0 – 1 d 1 – 3 d 3 – 7 d 7 – 30 d 1 – 3 mo 3 – 6 mo 6 – 12 mo 1 – 3 y 3 – 5 y 5 – 8 y 8 – 12 y 12 – 16 y
Heart 94 -155 91 - 158 90 - 166 106 - 182 120 - 179 105 - 185 108 - 169 89 - 152 73 - 137 65 - 133 62 - 130 60 - 120
Rate/Min (122) (122) (128) (149) (149) (141) (131) (119) (109) (100) (91) (80)
PR Interval 0.08 - 0.16 0.08 - 0.14 0.07 - 0.15 0.07 - 0.14 0.07 - 0.13 0.07 - 0.15 0.07 - 0.16 0.08 - 0.15 0.08 - 0.16 0.09 - 0.16 0.09 - 0.17 0.09 - 0.18
Lead II (0.107) (0.108) (0.102) (0.100) (0.098) (0.105) (0.106) (0.113) (0.119) (0.123) (0.128) (0.135)
(Seconds)
QRS Interval 0.02 - 0.07 0.02 - 0.07 0.02 - 0.07 0.02 - 0.08 0.02 - 0.08 0.02 - 0.08 0.03 - 0.08 0.03 - 0.08 0.03 - 0.07 0.03 - 0.08 0.04 - 0.09 0.04 - 0.09
Lead V5 (0.05) (0.05) (0.05) (0.05) (0.05) (0.05) (0.05) (0.06) (0.06) (0.06) (0.06) (0.07)
(Seconds)
Arrhythmia Recognition
Normal Sinus Rhythm
QRS
(in seconds)
P WaveRhythmHeart Rate PR Interval
(in seconds)
Before each QRS,
identical
Regular60 – 100 bpm 0.12 to 0.20 < 0.12
Sinus Arrhythmia
QRS
(in seconds)
P WaveRhythmHeart Rate PR Interval
(in seconds)
Before each QRS,
identical
IrregularUsually
60 – 100 bpm
0.12 to 0.20 < 0.12
Sinus Tachycardia
QRS
(in seconds)
P WaveRhythmHeart Rate PR Interval
(in seconds)
Before each QRS,
identical
Regular> 100 bpm 0.12 to 0.20 < 0.12
Sinus Bradycardia
QRS
(in seconds)
P WaveRhythmHeart Rate PR Interval
(in seconds)
Before each QRS,
identical
Regular< 60 bpm 0.12 to 0.20 < 0.12
Sinus Arrest or SA Block
QRS
(in seconds)
P WaveRhythmHeart Rate PR Interval
(in seconds)
Identical before
each QRS.
P to P interval
may be fixed before
and after the pause
Irregular40 – 100 bpm 0.12 to 0.20 < 0.12
Premature Atrial Complexes — PACs
QRS
(in seconds)
P WaveRhythmHeart Rate PR Interval
(in seconds)
Premature and
abnormal.
May be hidden
IrregularN/A 0.12 to 0.20 < 0.12
Premature Atrial Complex — Isolated PAC
QRS
(in seconds)
P WaveRhythmHeart Rate PR Interval
(in seconds)
Premature and
abnormal.
May be hidden
IrregularN/A 0.12 to 0.20 < 0.12
Premature Atrial Complexes (Atrial Bigeminy)
Every other beat is a PAC
QRS
(in seconds)
P WaveRhythmHeart Rate PR Interval
(in seconds)
Premature and
abnormal.
May be hidden
IrregularN/A 0.12 to 0.20 < 0.12
Premature Atrial Complex with Aberrancy
QRS
(in seconds)
P WaveRhythmHeart Rate PR Interval
(in seconds)
Premature and
abnormal.
May be hidden
IrregularN/A 0.12 to 0.20 < 0.12
Abnormal shape
Atrial Tachycardia
QRS
(in seconds)
P WaveRhythmHeart Rate PR Interval
(in seconds)
Abnormal P before
each QRS
(difficult to see)
Regular140 – 250 bpm 0.12 to 0.20 < 0.12
Atrial Flutter
QRS
(in seconds)
P WaveRhythmHeart Rate PR Interval
(in seconds)
Flutter (F) waves usu-
ally the negative com-
ponent of the flutter
wave in II, III, aVF and
positive in V1
A: Regular
V: Regular,
group beating
or variable
A: 240 – 350 bpm
V: Varies with
conduction ratio
N/A < 0.12
Atrial Fibrillation
QRS
(in seconds)
P WaveRhythmHeart Rate PR Interval
(in seconds)
Absent
Fibrillatory (f) waves
IrregularA: 350 – 650 bpm
V: Slow to rapid
N/A < 0.12
Junctional Rhythm
QRS
(in seconds)
P WaveRhythmHeart Rate PR Interval
(in seconds)
Inverted in inferior
leads; before, during
or after the QRS;
may be absent
Regular40 – 60 bpm < 0.12 < 0.12
Accelerated Junctional Rhythm
QRS
(in seconds)
P WaveRhythmHeart Rate PR Interval
(in seconds)
May be sinus P wave
(AV dissociation)
Usually AV
dissociation be-
cause of digitalis
toxicity
60 – 100 bpm < 0.12 < 0.12
Junctional Tachycardia
QRS
(in seconds)
P WaveRhythmHeart Rate PR Interval
(in seconds)
Inverted, absent or
after QRS
RegularUsually
<140 bpm
< 0.12 < 0.12
Right Bundle Branch Block
QRS
(in seconds)
PR Interval
(in seconds)
P Wave Characteristics
≥ 0.120.12 to 0.20Before each QRS,
identical
RSR’ in V1
Left Bundle Branch Block
QRS
(in seconds)
PR Interval
(in seconds)
P Wave Characteristics
≥ 0.120.12 to 0.20Before each QRS,
identical
QS or rS in V1 and V2
ST elevation
Pre-excitation Syndrome
QRS
(in seconds)
PR Interval
(in seconds)
P Wave Characteristics
Usually > 0.10< 0.12Before each QRS,
identical
Delta wave
distorts initial QRS
First-Degree AV Block
QRS
(in seconds)
PR Interval
(in seconds)
P Wave Characteristics
< 0.12> 0.20Before each QRS,
identical
Regular rhythm
QRS
(in seconds)
PR Interval
(in seconds)
P Wave Characteristics
< 0.12Increasingly
prolonged
Conduction
intermittent
QRS dropped in a
repeating pattern
Second-Degree AV Block — Type I
(AV Wenckebach or Mobitz type I)
Second-Degree AV Block — Type II
(Mobitz type II)
QRS
(in seconds)
PR Interval
(in seconds)
P Wave Characteristics
Broad
≥ 0.12
Usually normal
and identical
(before and after a
blocked impulse)
Sinus Some P waves
are not conducted
Second-Degree AV Block — 2:1 AV Block
QRS
(in seconds)
PR Interval
(in seconds)
P Wave Characteristics
Narrow or broadNormal or prolongedSinus 2:1 AV conduction
Third-Degree (Complete) AV Block
QRS
(in seconds)
PR Interval
(in seconds)
P Wave Characteristics
Narrow or broadN/ANormal but not related
to QRS
AV dissociation
P Wave is buried in the T Wave.
NOTE: Notch is not present in other T Waves
Nonconducted Premature Atrial Complex
P Wave is buried in the T Wave.
NOTE: Notch is not present in other T Waves
QRS
(in seconds)
P WaveRhythmHeart Rate PR Interval
(in seconds)
Premature and
abnormal.
May be hidden
IrregularN/A None Absent
P P P P P P
Mid
Diastole Atrial
Contraction Isovolumic
Ventricular
Contraction
Ventricular
Ejection Isovolumic
Ventricular
Relaxation
