新生儿心电图解释指南(英).pdf
新生儿心电图解释指南(英).pdf
European Heart Journal (2002) 23, 1329–1344
doi:10.1053/euhj.2002.3274, available online at http://www.idealibrary.com on
Task Force ReportGuidelines for the interpretation of the neonatal
electrocardiogram
A Task Force of the European Society of Cardiology
P. J. Schwartz1 (Chair), A. Garson, Jr2, T. Paul3, M. Stramba-Badiale4,
V. L. Vetter5, E. Villain6 and C. Wren7
1Department of Cardiology, University of Pavia and IRCCS Policlinico S. Matteo, Pavia, Italy; 2University of
Virginia, Charlottesville, VA, U.S.A.; 3The Children’s Heart Program of South Carolina, Medical University of
South Carolina, Charleston, SC, U.S.A.; 4Pediatric Arrhythmias Center, IRCCS Istituto Auxologico Italiano,
Milan, Italy; 5Division of Pediatric Cardiology, Department of Pediatrics, Children’s Hospital of Philadelphia,
University of Pennsylvania School of Medicine, Philadelphia, PA, U.S.A.; 6Division of Pediatric Cardiology,
Department of Pediatrics, Hôpital Necker Enfants Malades, Paris, France; 7Department of Paediatric Cardiology,
Freeman Hospital, Newcastle upon Tyne, U.K.Correspondence: Peter J. Schwartz, MD, FESC, FACC,, FAHA,
Professor & Chairman, Department of Cardiology, Policlinico S.
Matteo IRCCS, Viale Golgi, 19-27100 Pavia, Italy.0195-668X/02/$35.00 2002 Published byIntroduction
Most cardiologists who care for adults have no
or minimal experience with electrocardiograms
(ECGs) recorded in infants. So far, this has had no
practical implications because only seldom are they
requested to examine a neonatal ECG. This situation,
however, may change as some European countries
have begun to consider the possibility of introduc-
ing in their National Health Services the performance
of an ECG during the first month of life in all
newborns, as part of a cardiovascular screening
programme.Introduction.............................................................1329
Normal electrocardiogram in the newborn .............1330
Normal values......................................................1330
Technology ..........................................................1330
Artefacts...............................................................1332
Electrocardiographic measurements ....................1332
Heart rate.............................................................1332
P wave..................................................................1332
QRS complex.......................................................1332
QT interval ..........................................................1333
ST segment and T wave ......................................1333
Abnormal electrocardiogram in the newborn .........1333
Heart rate.............................................................1333
Sinus arrhythmia..............................................1333
Sinus tachycardia .............................................1333
Sinus bradycardia.............................................1335
Other bradycardias...........................................1335
P wave..................................................................1335
Atrioventricular conduction.................................1335
Complete (3rd) atrioventricular block .............1335
1st and 2nd atrioventricular block...................1336
Intraventricular conduction .................................1336
Bundle branch block ........................................1336
Non-specific intraventricular conduction
abnormalities....................................................1336
Wolff–Parkinson–White syndrome ..................1336
QRS axis and amplitude......................................1338
Right ventricular hypertrophy .........................1338E
Left ventricular hypertrophy............................1338
Low QRS voltage.............................................1338
Ventricular repolarization....................................1338
QT prolongation: differential diagnosis ...........1339
Long QT syndrome..........................................1339
ST segment elevation .......................................1341
Atrial and ventricular arrhythmias......................1341
Atrial/junctional ...............................................1341
Premature atrial beats ..................................1341
Supraventricular tachycardia........................1342
Atrial flutter .................................................1342
Ventricular arrhythmias ...................................1342
Premature ventricular beats..........................1342
Ventricular tachycardia ................................1343
Accelerated ventricular rhythm ....................1343
Conclusion...............................................................1343
Acknowledgements ..................................................1343
References................................................................1343lsevier Science Ltd on behalf of The European Society of Cardiology
1330 Task Force ReportThe background of this evolution is multiple, but it
lies largely in the realization that early identification
of life-threatening arrhythmogenic disorders, which
often manifest in infancy, childhood or even later,
may allow initiation of effective preventive therapy. A
large prospective study has indicated that some in-
fants with prolonged QT interval in the first week of
life had sudden death, and would have previously
been labelled as victims of the Sudden Infant Death
Syndrome[1]. Furthermore, in infants with this diag-
nosis, post-mortem molecular screening may reveal
the presence of the long QT syndrome (LQTS)[2]. As
with most screening tests, a single ECG must be put
into context (e.g. family history, etc.). Additionally, it
is traditional to examine neonatal ECGs looking for
those with parameters below the 2nd or exceeding
the 98th percentile. While it is true that these
values are ‘abnormal’ in a strict statistical sense, very
often ‘abnormality’ does not imply the presence of a
disease, or of a risk for clinically relevant events. This
depends largely on the parameter under examination.
However, also the reverse may be true and, in the
neonate, a completely normal ECG may be seen with
multiple types of congenital heart defects and with the
entire spectrum of arrhythmias. This call for caution
does not detract from the valid concept that the
identification of ECG abnormalities in the newborn
can be the first step toward a meaningful act of
preventive medicine.
Should this neonatal screening indeed be intro-
duced as part of National Health Services, then hos-
pital cardiologists — most of whom are unfamiliar
with neonatal ECGs — would be asked to read these
tracings. The European Society of Cardiology (ESC)
has realized the potential implications for European
cardiologists and for health care, and has acted ac-
cordingly. Through the Committee for Practice
Guidelines and Policy Conferences, chaired by
Werner Klein, it has instituted this Task Force. The
experts were designated by the Guidelines Committee
and approved by the Board of the ESC. The panel
was composed of physicians and scientists involved in
clinical practice in University and non-University hos-
pitals. Members were selected to represent experts of
different European countries; in addition, two non-
European members were included for their worldwide
recognized expertise in the field of pediatric electro-
cardiography.
The ESC considers medical education and the
improvement of clinical practice among its major
obligations. The main objective of the present report
is to present adult cardiologists with a consensus
document designed to provide guidelines for the
interpretation of the neonatal ECG, focusing on
the most clinically relevant abnormalities and on the
ensuing management and referral options. This
document aims also at providing paediatricians and
neonatologists with updated information of clinical
relevance that can be detected from a neonatal
ECG.Eur Heart J, Vol. 23, issue 17, September 2002The procedure used for developing and issuing these
guidelines was in accordance with the recently issued
‘Recommendations for Task Force creation and report
writing’, (http://www.escardio.org/scinfo/guidelines_
recommendations.htm) which is a position document of
the ESC Committee for Practice Guidelines and Policy
Conferences.
This document was reviewed and approved by the
Commitee for Practice Guidelines and Policy Confer-
ences. It was endorsed by the Board of the ESC and
represents the official position of the ESC with regard to
this subject. These guidelines will be reviewed two years
after publication and considered as current unless the
‘Guidelines’ Committee revises or withdraws them from
circulation.
This Task Force was financed by the budget of the
Committee for Practice Guidelines and Policy Confer-
ences of the ESC and was independent of any commer-
cial, health or governmental authorities.Normal electrocardiogram in the
newbornNormal values
Changes occur in the normal ECG from birth to adult
life. They relate to developmental changes in physiology,
body size, the position and size of the heart relative to
the body, and variations in the size and position of the
cardiac chambers relative to each other. The major
changes in the paediatric ECG occur in the first year of
life with the majority of normal adult values being
abnormal in the newborn. Likewise, many normal new-
born values and patterns would be abnormal in the
adult. Normal electrocardiographic values in the paedi-
atric population traditionally derive from those pub-
lished in 1979 by Davignon et al.[3]. From the ECGs of
1027 infants less than 1 year of age and among these, 668
in the first month of life, the percentile distribution of
electrocardiographic variables was calculated. It is im-
portant to refer to tables of normal values as shown in
Table 1. A recent large study by Rijnbeek et al.[4]
included an extremely low number of neonates (n=44)
but no one below 3 weeks of age. Thus, the percentile
tables published by Davignon are recommended for use
in clinical practice. Other references on the reading of
ECGs in neonates and children are available[5,6].Technology
The normal newborn ECG should include 12 leads.
Other leads, V3R, V4R and V7, may provide additional
information to evaluate possible congenital heart
lesions.
The current use of computerized digital ECG systems
affects newborn ECGs to a greater extent than those of
older children or adults[7]. The newborn ECG may have
Task Force Report 1331T
ab
le
1
N
or
m
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ne
on
at
al
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C
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st
an
da
rd
s*
A
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ra
te
(b
ea
ts
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in
1
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F
ro
nt
al
pl
an
e
Q
R
S
ax
is
a
(d
eg
re
es
)
P
w
av
e
am
pl
it
ud
e
(m
m
)
P
-R
in
te
rv
al
a
(s
)
Q
R
S
du
ra
ti
on
a
V
5
Q
II
Ic
(m
m
)
Q
V
6
c
(m
m
)
R
V
1
b
(m
m
)
SV
1
b
(m
m
)
R
/S
V
1
c
R
V
6
b
(m
m
)
SV
6
b
(m
m
)
R
/S
V
6
c
SV
1
+
R
V
6
c
(m
m
)
R
+
SV
4
c
(m
m
)
0–
1
da
ys
93
–1
54
(1
23
)
+
59
to
+
19
2
(1
35
)
2·
8
0·
08
–0
·1
6
(0
·1
1)
0·
02
–0
·0
8
(0
·0
5)
5·
2
1·
7
5–
26
0–
22
·5
9·
8
0–
11
0–
9·
8
10
28
52
1–
3
da
ys
91
–1
59
(1
23
)
+
64
to
+
19
7
(1
34
)
2·
8
0·
08
–0
·1
4
(0
·1
1)
0·
02
–0
·0
7
(0
·0
5)
5·
2
2·
1
5–
27
0–
21
6
0–
12
0–
9·
5
11
29
52
3–
7
da
ys
90
–1
66
(1
29
)
+
77
to
+
18
7
(1
32
)
2·
9
0·
08
–0
·1
4
(0
·1
0)
0·
02
–0
·0
7
(0
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5)
4·
8
2·
8
3–
24
0–
17
9·
7
0·
5–
12
0–
9·
8
10
25
48
7–
30
da
ys
10
7–
18
2
(1
49
)
+
65
to
+
16
0
(1
10
)
3·
0
0·
07
–0
·1
4
(0
·1
0)
0·
02
–0
·0
8
(0
·0
5)
5·
6
2·
8
3–
21
·5
0–
11
7
2·
5–
16
0–
9·
8
12
22
47
1–
3
m
on
th
s
12
1–
17
9
(1
50
)
+
31
to
+
11
4
(7
5)
2·
6
0·
07
–0
·1
3
(0
·1
0)
0·
02
–0
·0
8
(0
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5)
5·
4
2·
7
3–
18
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0–
12
·5
7·
4
5–
21
0–
7·
2
12
29
53
F
ro
m
re
f.
[3
].
a
2n
d–
98
th
pe
rc
en
ti
le
(m
ea
n)
b
2n
d–
98
th
pe
rc
en
ti
le
(1
m
m
=
10
0
V
)
c 9
8t
h
pe
rc
en
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le
(1
m
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=
10
0
V
)
Eur Heart J, Vol. 23, issue 17, September 2002
1332 Task Force Reporta higher voltage and shorter duration QRS complexes
resulting in a higher percentage of high frequency com-
ponents. The recommendations of a number of groups
vary as to the best bandwidth cutoffs and sampling
frequency to reduce error[8,9]. Higher bandwidth cutoffs
may alter amplitude of signals by as much as 46%[10].
This would make standards determined from analogue
signals or digitized signals at lower sampling rates and
lower frequency cutoffs different from those at higher
settings. The current American Heart Association rec-
ommendation for paediatric ECGs is 150 Hz as a mini-
mum bandwidth cutoff and 500 Hz as a minimum
sampling rate[11]. The Rijnbeek study reported normals
using a higher sampling rate of 1200 Hz. Compared to
Davignon’s study, which used a sampling rate of 333 Hz,
the newborn upper limits in Rijnbeek’s study were
12–25% higher than in Davignon’s[3,4].Artefacts
Artefacts are common in newborn ECGs and include
limb lead reversal and incorrect chest lead positioning.
In addition, electrical interference, usually 60 cycles,
can occur in hospital settings from bedside monitors,
warmers or other equipment.
Other artefacts occur because of various types of
patient movement common in neonates. These artefacts
may be random as with hiccoughs or limb movement.
Normal complexes are seen along with the artefacts, and
the intrinsic rhythm of the patient is not affected. Other
common artefacts include a fine, often irregular undu-
lation of the baseline from muscle tremors or jitteriness.
Again, the intrinsic rhythm is not affected. The size of
the QRS complex and the baseline may wander in a
cyclic fashion with respirations. It should be noted that
the neonate breathes from 30–60 times per min.
The main clue in determining the presence of an
artefact is to evaluate whether it affects the intrinsic
rhythm and if it is timed such that it could be a true
depolarization. A signal within 80 ms from a true QRS
complex could not occur from an electrophysiologic
point of view.Electrocardiographic measurements
Because of the current limitations of electronic measure-
ments in newborn ECGs, intervals should be hand
measured as the computerized systems are often inaccu-
rate in the newborn. Intervals in children increase with
increasing age, reaching most of the adult normal values
by 7–8 years of age.Heart rate
Heart rate can be determined by a variety of methods. It
should be noted that normal neonates may have ratesEur Heart J, Vol. 23, issue 17, September 2002between 150–230 beats . min1, especially if they are
crying or agitated. Over 200 beats . min1, one-half
small box can make an appreciable difference in heart
rates.
Heart rates between the 2nd and 98th percentile in the
first year of life are shown in Table 1. The normal heart
rate increases from the first day of life, it reaches a peak
between the first and the second month and then de-
clines returning to the values recorded at birth by the
sixth month. During the following 6 months, it remains
rather stable and then slowly declines after 1 year due to
maturation of vagal innervation of the sinus node[12].
Clinically significant gender differences in heart rate are
not seen in the neonatal period.P wave
The P wave axis is a vector indicating the direction of
activation, which is away from the site of origin. By
identifying the quadrant location of the P wave axis one
can determine the site of origin of the rhythm. For
example, sinus rhythm originates in the high right
atrium transcribing a P wave with an axis in the quad-
rant bordered by 0 and +90. Measurements are avail-
able for P wave amplitude (Table 1). The P wave is
generally pointed in lead II and aVF and more rounded
in other leads. Lead V1 may be diphasic.
The PR interval is measured from the onset of the P
wave to the Q or R wave if no Q wave is present. The PR
interval, measured in lead II, increases with age and
decreases with heart rate. The normal neonatal PR
interval ranges from a minimum of 70 ms to a maximum
of 140 ms, with a mean of 100 ms.QRS complex
The normal full-term neonate has an axis between 55
and 200 but by 1 month, the normal upper limit has
fallen to 160 or less. Although one might identify an
axis of 120 as right axis deviation in an adult, it is a
normal finding in a newborn. The QRS axis in the
premature newborn ECG ranges between 65 and 174.
The duration of the QRS complex is measured from
the beginning to the end of the ventricular depolariz-
ation complex and it should be measured in a lead with
an initial Q wave[5]. QRS duration in the newborn and
infant is narrow (<80 ms). Normal QRS duration in-
creases with age. Normal values for QRS complex
duration in lead V5 are displayed in Table 1.
QRS morphology in the newborn may have more
notches and direction changes than seen in older chil-
dren or adults. The direction of the Q wave in the
precordial or horizontal plane indicates the direction of
septal depolarization. Normally, there is a Q wave in
leads V5–V6 indicating depolarization from left to right.
Normal values of Q wave amplitudes vary with the lead
and with age. Q wave amplitudes may be as high
Task Force Report 1333as 0·55 mV in lead III or 0·33 mV in aVF at 1 month.
Q wave duration >30 ms is abnormal. The appearance
of secondary r waves (r or R) in the right chest leads
is frequent in normal neonates.
Davignon et al.[3] provided ‘normal’ values in infants.
The use of 2nd and 98th percentiles to define normality
implies that 4% of the population are ‘abnormal’ for any
given single measurement, so ‘normal’ ranges have to be
interpreted with caution (Table 1). Thomaidis et al.
published normal voltages from healthy term and
premature neonates[13].QT interval
The QT interval is the interval between the beginning of
the QRS complex and the end of the T wave. The QT
measurement should be made in leads II, V5, and V6
with the longest value being used. The main difficulty lies
in identifying correctly the point where the descending
limb of the T wave intersects the isoelectric line. Due to
the fast heart rate of infants the P wave may be
superimposed on the T wave, particularly when the QT
interval is prolonged. In this case, the end of the T wave
should be extrapolated by drawing a tangent to the
downslope of the T wave and considering its intersection
with the isoelectric line.
The QT interval duration changes with rate and it is
usually corrected (QTc) by using Bazett’s formula. Cor-
rection of the QT interval requires a stable sinus rhythm
without sudden changes in the RR interval. QTc is equal
to QT interval in seconds divided by the square root of
the preceding RR interval in seconds. To avoid time-
consuming calculations, a simple chart (Fig. 1) where
the value of QTc is easily obtained by matching QT and
RR interval in millimetres (given the paper speed at
25 mm . s1) has been produced. When heart rate is
particularly slow or fast the Bazett’s formula may not be
accurate in the correction but it remains the standard for
clinical use.
The mean QTc on the 4th day of life is 40020 ms[1]
and, at variance with the adult, no gender differences are
present[14]. Therefore, the upper normal limit of QTc (2
standard deviations above the mean, corresponding to
the 97·5 percentile) is 440 ms. By definition, 2·5% of
normal newborns are expected to have a QTc greater
than 440 ms. In healthy infants there is a physiological
prolongation of QTc by the second month (mean
410 ms) followed by a progressive decline[15], so that by
the sixth month QTc returns to the values recorded in
the first week.Pitfalls with QT measurement. Despite its apparent
simplicity the measurement of the QT interval is fraught
with errors. The simple fact that a small square on the
ECG paper is equivalent to 40 ms explains why healthy
scepticism should accompany claims of clinical impor-
tance attached to very small degrees of ‘QT prolon-
gation’. An attempt should be made to measure with10 ms (1/4 of a mm) while we recognize that this may be
within measurement error.ST segment and T wave
ST segment elevations >1 mm above the isoelectric line
are uncommon in the newborn. In neonates and infants
it is better to consider as the isoelectric line the TP
segment instead of the PQ segment. T waves are nor-
mally quite variable in the first week of life. After
1 week, the T wave is negative in lead V1 and positive
in V5–V6.Abnormal electrocardiogram in the
newbornHeart rateSinus arrhythmia
Since sinus arrhythmia is less pronounced at fast heart
rate, neonates show a more regular rhythm than young
children and adolescents, particularly in the first week of
life. Sinus arrhythmia should be differentiated from
wandering pacemaker, which manifests itself with a
gradual change of P wave axis and morphology and that
is due to a shift of the pacemaker from the sinus node
to the atrium and the atrioventricular (AV) junction.
Although wandering pacemaker may accompany other
types of bradyarrhythmia, it has no pathologic meaning.
Work-up
No work-up should be necessary unless significant
bradycardia coexists.Sinus tachycardia
Sinus tachycardia is a sinus rhythm with a heart rate
above the normal limit for age. In the newborn the
upper normal limit (98th percentile) is 166 beats . min1
in the first week and 179 beats . min1 in the first
month. After the sixth month the upper normal limit
declines to approximately 160 beats . min1 and at
1 year is 151 beats . min1. These values have been
measured from ECGs recorded when infants were awake
and quiet. It has to be noted that newborn infants may
transiently reach a heart rate up to 230 beats . min1.
Causes. Sinus tachycardia may be a sign of any con-
dition associated with an increase of cardiac output. The
most frequent causes of sinus tachycardia in the neo-
natal period are represented by fever, infection, anae-
mia, pain, and dehydration (hypovolaemia). Other
causes of sinus tachycardia include neonatal hyper-
thyroidism and myocarditis, particularly when it is not
proportionate to the level of fever. Myocarditis is
usually, but not necessarily, associated with other clini-
cal signs, such as gallop rhythm, or ECG abnormalities,
including T wave changes and conduction disturbances.Eur Heart J, Vol. 23, issue 17, September 2002
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