The normal pediatric ECG
There are many systematic techniques for interpreting ECGs and no one
method is particularly better than another. A caveat to the electronic interpretation
that many ECG machines conduct is that they are manufactured
and calibrated with adult values in the software package; hence, the machine
interpretation is frequently inaccurate with children. On the other hand,
they are reasonably accurate in calculating intervals that are averaged
over the entire recording period. The settings of the ECG, however, must
be full standard, defined as 10 mm/mV with a standard paper speed of 25
mm/sec. These settings can be changed on the machine to elucidate certain
features, but a standard ECG is the only one that should be referenced to
normal values. Frequently, additional right ventricular and posterior left
ventricular precordial leads (V3R, V4R, and V7) are included with pediatric
ECGs to provide additional information on patients who have complex congenital
abnormalities. In most pediatric patients, these leads can be ignored.
Table 1 lists the normal pediatric ECG values seen in the newborn,
infant, child, and adolescent [3–5]. This table lists normal ranges for heart
rate, QRS axis, PR and QRS complex intervals, and R- and S-wave amplitudes,
all of which significantly change with age. Rapid changes occur over
the first year of life as a result of the dramatic changes in circulation and
cardiac physiology. After infancy, subsequent changes are more gradual
until late adolescence and adulthood.
Heart rate
In children, cardiac output is determined primarily by heart rate as
opposed to stroke volume. With age, the heart rate decreases as the ventricles
mature and stroke volume plays a larger role in cardiac output.
Age and activity-appropriate heart rates thus must be recognized. Average
resting heart rate varies with age; newborns can range from 90–160 beats per
minute (bpm) and adolescents from 50–120 bpm. The average heart rate
peaks about the second month of life and thereafter gradually decreases until
adolescence (Fig. 1). Heart rates grossly outside the normal range for age
should be scrutinized closely for dysrhythmias
QRS axis
In utero, blood is shunted away from the lungs by the patent ductus
arteriosus, and the right ventricle provides most of the systemic blood
flow. As a result, the right ventricle is the dominant chamber in the newborn
infant. In the neonate and young infant (up to 2 months), the ECG shows
right ventricular dominance and right QRS axis deviation (Fig. 1). Most
of the QRS complex is reflective of right ventricular mass. Across the precordium,
the QRS complex demonstrates a large amplitude R wave (increased
R-/S-wave ratio) in leads V1 and V2, and small amplitude R wave
(decreased R-/S-wave ratio) in leads V5 and V6. As the cardiac and circulatory
physiology matures, the left ventricle becomes increasingly dominant.
Over time, the QRS axis shifts from rightward to a more normal position,
and the R-wave amplitude decreases in leads V1 and V2 and increases in
leads V5 and V6
PR interval
Similarly, the PR interval also varies with age, gradually increasing with
cardiac maturity and increased muscle mass. In neonates, it ranges from
0.08–0.15 sec and in adolescents from 0.120–0.20 sec [3]. The normal shorter
PR interval in children must be taken into account when considering the
diagnosis of conduction and atrioventricular (AV) block.
QRS complex duration
The QRS complex duration varies with age. In children, the QRS complex
duration is shorter, possibly because of decreased muscle mass, and
gradually increases with age. In neonates it measures 0.030–0.08 sec and
in adolescents 0.05–0.10 sec. A QRS complex duration exceeding 0.08 sec
in young children (younger than 8 years of age) or exceeding 0.10 sec in
older children may be pathologic. As a result, slight prolongation of what
may appear as a normal QRS complex can indicate a conduction abnormality
or bundle branch block in children.
QT interval
Because the QT interval varies greatly with heart rate, it is usually corrected
(QTc), most commonly using Bazett’s formula: QTc ¼ QT/ORR interval.
During the first half of infancy, the normal QTc is longer than in
older children and adults. In the first 6 months of life, the QTc is considered
normal at less than 0.49 sec. After infancy, this cutoff is generally 0.44 sec.
T waves
In pediatric patients, T-wave changes on the ECG tend to be nonspecific
and are often a source of controversy. What is agreed on is that flat or inverted
T waves are normal in the newborn. In fact, the T waves in leads V1
through V3 usually are inverted after the first week of life through the age of
8 years as the so-called ‘‘juvenile’’ T-wave pattern (see Fig. 1). In addition,
this pattern can persist into early adolescence (Fig. 2). Upright T waves in
V1 after 3 days of age can be a sign of right ventricular hypertrophy (RVH).
Chamber size
An assessment of chamber size is important when analyzing the pediatric
ECG for underlying clues to congenital heart abnormalities. P waves greater
than 2 mV (2 small boxes) in infants and greater than 3 mV (3 small boxes)
in adolescents may indicate right atrial enlargement (RAE). Because the
right atrium depolarizes before the left atrium, P-wave duration greater
than 0.08 sec (2 small boxes) in infants and 0.12 sec (3 small boxes) in adolescents
indicates left atrial enlargement (LAE).
RVH is best seen in leads V1 and V2 with an rSR#, QR (no S), or a pure R
(no Q or S) wave. RVH also may be suggested by the presence of a large S
wave in lead V6, upright T waves in leads V1–V3 after the first week of life,
or persistence of the right ventricular dominance pattern of the neonate.
Similarly, left ventricular hypertrophy (LVH) is suggested with the presence
of tall R waves in lead V6, large S wave in lead V1, left ventricular ‘‘strain’’
pattern in leads V5 and V6, and a mature precordial R-wave progression in
the newborn period. Biventricular hypertrophy is seen when ECG criteria
for enlargement of both ventricles is seen
source:
Pediatric ECG
Ghazala Q. Sharieff, MDa,b,*, Sri O. Rao, MDc
aChildren’s Hospital and Health Center/University of California–San Diego,
3020 Children’s Way, San Diego, CA 92123
bPediatric Emergency Medicine, Palomar-Pomerado Hospitals/California
Emergency Physicians, 555 East Valley Parkway, Escondido, CA 92025, USA
cDivision of Pediatric Cardiology, Children’s Hospital and Health Center,
3020 Children’s Way, San Diego, CA 92123, USA
There are many systematic techniques for interpreting ECGs and no one
method is particularly better than another. A caveat to the electronic interpretation
that many ECG machines conduct is that they are manufactured
and calibrated with adult values in the software package; hence, the machine
interpretation is frequently inaccurate with children. On the other hand,
they are reasonably accurate in calculating intervals that are averaged
over the entire recording period. The settings of the ECG, however, must
be full standard, defined as 10 mm/mV with a standard paper speed of 25
mm/sec. These settings can be changed on the machine to elucidate certain
features, but a standard ECG is the only one that should be referenced to
normal values. Frequently, additional right ventricular and posterior left
ventricular precordial leads (V3R, V4R, and V7) are included with pediatric
ECGs to provide additional information on patients who have complex congenital
abnormalities. In most pediatric patients, these leads can be ignored.
Table 1 lists the normal pediatric ECG values seen in the newborn,
infant, child, and adolescent [3–5]. This table lists normal ranges for heart
rate, QRS axis, PR and QRS complex intervals, and R- and S-wave amplitudes,
all of which significantly change with age. Rapid changes occur over
the first year of life as a result of the dramatic changes in circulation and
cardiac physiology. After infancy, subsequent changes are more gradual
until late adolescence and adulthood.
Heart rate
In children, cardiac output is determined primarily by heart rate as
opposed to stroke volume. With age, the heart rate decreases as the ventricles
mature and stroke volume plays a larger role in cardiac output.
Age and activity-appropriate heart rates thus must be recognized. Average
resting heart rate varies with age; newborns can range from 90–160 beats per
minute (bpm) and adolescents from 50–120 bpm. The average heart rate
peaks about the second month of life and thereafter gradually decreases until
adolescence (Fig. 1). Heart rates grossly outside the normal range for age
should be scrutinized closely for dysrhythmias
QRS axis
In utero, blood is shunted away from the lungs by the patent ductus
arteriosus, and the right ventricle provides most of the systemic blood
flow. As a result, the right ventricle is the dominant chamber in the newborn
infant. In the neonate and young infant (up to 2 months), the ECG shows
right ventricular dominance and right QRS axis deviation (Fig. 1). Most
of the QRS complex is reflective of right ventricular mass. Across the precordium,
the QRS complex demonstrates a large amplitude R wave (increased
R-/S-wave ratio) in leads V1 and V2, and small amplitude R wave
(decreased R-/S-wave ratio) in leads V5 and V6. As the cardiac and circulatory
physiology matures, the left ventricle becomes increasingly dominant.
Over time, the QRS axis shifts from rightward to a more normal position,
and the R-wave amplitude decreases in leads V1 and V2 and increases in
leads V5 and V6
PR interval
Similarly, the PR interval also varies with age, gradually increasing with
cardiac maturity and increased muscle mass. In neonates, it ranges from
0.08–0.15 sec and in adolescents from 0.120–0.20 sec [3]. The normal shorter
PR interval in children must be taken into account when considering the
diagnosis of conduction and atrioventricular (AV) block.
QRS complex duration
The QRS complex duration varies with age. In children, the QRS complex
duration is shorter, possibly because of decreased muscle mass, and
gradually increases with age. In neonates it measures 0.030–0.08 sec and
in adolescents 0.05–0.10 sec. A QRS complex duration exceeding 0.08 sec
in young children (younger than 8 years of age) or exceeding 0.10 sec in
older children may be pathologic. As a result, slight prolongation of what
may appear as a normal QRS complex can indicate a conduction abnormality
or bundle branch block in children.
QT interval
Because the QT interval varies greatly with heart rate, it is usually corrected
(QTc), most commonly using Bazett’s formula: QTc ¼ QT/ORR interval.
During the first half of infancy, the normal QTc is longer than in
older children and adults. In the first 6 months of life, the QTc is considered
normal at less than 0.49 sec. After infancy, this cutoff is generally 0.44 sec.
T waves
In pediatric patients, T-wave changes on the ECG tend to be nonspecific
and are often a source of controversy. What is agreed on is that flat or inverted
T waves are normal in the newborn. In fact, the T waves in leads V1
through V3 usually are inverted after the first week of life through the age of
8 years as the so-called ‘‘juvenile’’ T-wave pattern (see Fig. 1). In addition,
this pattern can persist into early adolescence (Fig. 2). Upright T waves in
V1 after 3 days of age can be a sign of right ventricular hypertrophy (RVH).
Chamber size
An assessment of chamber size is important when analyzing the pediatric
ECG for underlying clues to congenital heart abnormalities. P waves greater
than 2 mV (2 small boxes) in infants and greater than 3 mV (3 small boxes)
in adolescents may indicate right atrial enlargement (RAE). Because the
right atrium depolarizes before the left atrium, P-wave duration greater
than 0.08 sec (2 small boxes) in infants and 0.12 sec (3 small boxes) in adolescents
indicates left atrial enlargement (LAE).
RVH is best seen in leads V1 and V2 with an rSR#, QR (no S), or a pure R
(no Q or S) wave. RVH also may be suggested by the presence of a large S
wave in lead V6, upright T waves in leads V1–V3 after the first week of life,
or persistence of the right ventricular dominance pattern of the neonate.
Similarly, left ventricular hypertrophy (LVH) is suggested with the presence
of tall R waves in lead V6, large S wave in lead V1, left ventricular ‘‘strain’’
pattern in leads V5 and V6, and a mature precordial R-wave progression in
the newborn period. Biventricular hypertrophy is seen when ECG criteria
for enlargement of both ventricles is seen
source:
Pediatric ECG
Ghazala Q. Sharieff, MDa,b,*, Sri O. Rao, MDc
aChildren’s Hospital and Health Center/University of California–San Diego,
3020 Children’s Way, San Diego, CA 92123
bPediatric Emergency Medicine, Palomar-Pomerado Hospitals/California
Emergency Physicians, 555 East Valley Parkway, Escondido, CA 92025, USA
cDivision of Pediatric Cardiology, Children’s Hospital and Health Center,
3020 Children’s Way, San Diego, CA 92123, USA
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thanks admin about this topic
we hope to write more about ECG in children
thanks again