1
Pediatric ECG Cases: Benign Variants or
Life-Threatening Abnormalities?
Although most physicians are familiar with the normal limits of ECG intervals for adults, it may not be
immediately apparent that children have different normal values. Population studies have helped to
formulate generally accepted normal values for children at various ages,[1] which should be referenced
when interpreting an ECG. However, even with these values, it may be difficult to make a diagnosis.
Variation occurs in children depending on age and sex, but most pathologic conditions fall well outside
the range of normal. See whether you can determine whether the ECGs in the following cases are
benign variants from the norm or cause for concern. Image courtesy of Wikimedia Commons.
2
A 16-year-old male is brought to the emergency department (ED) with chest pressure and mild
dyspnea. His 12-lead ECG is shown. This is not the first occurrence, but it is the first time he has
brought it to the attention of his parents. There has been slight exercise intolerance. On
examination, his blood pressure is 108/50 mm Hg and his heart rate is approximately 60
beats/min and regular. He has a nontender chest wall.
What is the next step in the patient’s management?
A. Prepare for possible transcutaneous pacing
B. Administer intravenous atropine at 0.02 mg/kg
C. Do nothing, because this is a benign pediatric ECG finding
D. Begin amiodarone therapy
E. Admit for electrophysiology study
3
Answer: C. Do nothing, because this is a benign pediatric ECG finding
This ECG shows an ectopic junctional rhythm. Note the regular rhythm with an absence of P
waves (purple arrows). Retrograde P waves can sometimes be found just after the QRS complex
or slightly buried in the T waves. In children, a junctional rhythm is most often a benign finding.
It may be caused by acute stressors, such as infection, oxygen desaturation, and stimulation of
the vagus nerve. This patient’s rate increased appropriately with a short trial of exercise in the
ED. Despite some prominent precordial QRS complexes, this patient does not have left
ventricular hypertrophy. It would be reasonable to arrange for outpatient follow-up with a
pediatric cardiologist.[2]
4
A 15-year-old male experienced a syncopal episode during his first high school basketball game.
He was brought to the ED by ambulance for evaluation. His ECG is shown. Recognizing the
potential abnormality, you advise the patient to avoid participating in any strenuous activity until
he receives a full evaluation from a cardiologist.
What structural abnormality is suggested by the ECG shown?
A. Accessory pathway
B. Ventricular septal defect
C. Ebstein anomaly
D. Hypertrophic cardiomyopathy
E. Anomalous coronary artery
5
Answer: D. Hypertrophic cardiomyopathy
The ECG shows prominent septal R waves in V1 (blue arrows) and septal Q waves in anterior
leads (red arrows) and lateral leads (V3-V6), which are consistent with hypertrophic
cardiomyopathy with characteristic septal hypertrophy. On examination, a characteristic systolic
murmur that decreases with squatting and increases with the Valsalva maneuver or tight hand
grip, is expected. Definitive diagnosis is made by echocardiography, which should be obtained in
anticipation of pediatric cardiology evaluation. Initial medical management is often focused on
maintaining adequate hydration and beta-blockade. With syncope, it is important to discern
outflow obstruction from ventricular arrhythmia, often by exercise echocardiography.
Amiodarone can reduce the incidence of sudden cardiac death.[3-5]
6
An 11-year-old girl from Martha’s Vineyard is being evaluated at an outpatient pediatric clinic
for low-grade fever and exercise intolerance on the soccer field, which manifests as easy fatigue
and generalized weakness. Her 12-lead ECG and magnified rhythm strip are shown. Until
recently, she has been completely healthy and developing normally and has had no palpitations,
chest pain, syncope, or exercise intolerance. There are no cardiac medications in the household.
What is the next step in management?
A. Do nothing, because this is a benign pediatric ECG finding
B. Obtain an echocardiogram to evaluate for congenital heart disease
C. Begin transcutaneous pacing immediately
D. Obtain Lyme disease serologies
E. Begin isoproterenol therapy
7
Answer: D. Obtain Lyme disease serologies
This child has presented with first-degree atrioventricular (AV) block, as evidenced by the
markedly prolonged PR interval of approximately 310 ms. This is most often a normal variant in
the pediatric population as a result of increased vagal tone, particularly in runners.
Asymptomatic first-degree AV block often requires no further workup or treatment; however,
many congenital, infectious, immunologic, or toxicologic conditions may also cause prolonged
PR intervals. This patient comes from an area where Lyme disease is endemic. Lyme disease can
present with heart block ranging from first-degree to complete. In this patient, Lyme titers were
positive, and she was treated with a course of doxycycline. Repeated ECG several weeks later
demonstrated a return of the PR interval to a normal value.[6]
8
A 12-year-old male athlete is brought to the ED by his parents after he experienced chest pain.
Upon arrival, he has reproducible chest-wall tenderness. The parents insist that he receive an
ECG because a local middle-school athlete recently died during a sporting event. The ECG is
noted to be “abnormal” by the machine (and the concerned parents).
What is the next step in management?
A. Obtain at least 2 sets of cardiac enzyme values
B. Obtain cardiology consult in the ED
C. Refer for 2-dimensional echocardiography
D. Reassure the patient and his parents
E. Admit for observation
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Answer: D. Reassure the patient and his parents
The 12-lead ECG shows T-wave inversions in the right precordial leads (red arrows); these are
normal findings. The T-wave morphology in V1-V3 is dynamic throughout childhood.
Newborns up to 3 days of life will have upright T waves in V1, but this lead will invert within
the first week of life. T waves in leads V2 and V3 also invert in early childhood; in fact, upright
T waves at a young age may be abnormal. They will progressively become upright in most
children in the order of V3, V2, and V1 by the teenage years. This conversion is already
becoming evident in the preteen patient, as V3 has a nearly flat to biphasic T wave.[3,7]
10
6-year-old girl is found to have a systolic murmur on routine examination at the pediatrician’s
office. Her 12-lead ECG and magnified rhythm strip is shown. The family just moved to the
area, so this is the first time the child has been examined by this physician. There is no
documentation of a murmur in the records transferred from her previous pediatrician. Thus, the
child is referred for a routine cardiologic evaluation.
What is the most appropriate interpretation?
A. Atrial fibrillation
B. Sick sinus syndrome
C. Second-degree Mobitz type I AV block
D. Premature atrial contractions
E. Sinus arrhythmia
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Answer: E. Sinus arrhythmia
The child has sinus arrhythmia, which is particularly impressive in this ECG. Sinus arrhythmia is
an exaggerated but normal variation of the sinus rhythm that occurs with respiration. On
examination, this may be prominent enough to manifest as an irregular pulse. Sinus arrhythmia is
almost universal in the pediatric population, but it may not be as dramatic as the example shown.
No further testing is needed on the basis of this ECG, but depending on the quality of the
probably innocent flow murmur, echocardiography may be warranted.[3]
12
A 16-year-old male is being evaluated in the ED for a syncopal episode. As part of the workup, a
12-lead ECG is obtained (shown). He is an athlete, but the syncopal episode occurred while
standing at home. He has not been feeling well over the past 24-48 hours, with worsening fever,
headaches, myalgia, and arthralgia. He is experiencing chest pain but is unsure whether it differs
from the aches and pains he has felt all over his body during this time.
What is the most appropriate interpretation?
A. Normal variant pediatric ECG
B. Sinus tachycardia
C. Pericarditis
D. Sinus rhythm with left ventricular hypertrophy
E. Acute ST-segment elevation myocardial infarction
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Answer: A. Normal variant pediatric ECG
The ST-segment elevations seen in the precordial leads are benign early repolarization with
elevated J points (purple arrows), which are normal variants in the pediatric population. The
morphology of the segments is concave (curving upward) and thus reassuring. Convex segments
(curving downward) are more concerning for acute myocardial infarction. The diffuse STsegment elevations typical of pericarditis are not present in this ECG; PR-segment depressions
are also absent. Although the lateral leads have elevated R-wave voltages, this finding is quite
common in young, thin athletes and carries no adverse prognosis.[3]
14
A 16-year-old male athlete is being seen for a physical examination before sports participation.
The patient’s ECG is shown. A focused history reveals that the patient has had palpitations in the
past and an episode of near-syncope, which he thought was due to overexerting himself. As a
result, he never went to the physician for it and has never had a workup.
In the event of acute supraventricular tachycardia, all of the following medications should be
avoided except:
A. Digoxin
B. Procainamide
C. Adenosine
D. Metoprolol
E. Verapamil
15
Answer: B. Procainamide
The patient has Wolff-Parkinson-White (WPW) syndrome (pre-excitation), as evidenced by the
characteristic delta waves, the shortened PR interval, and the widened QRS complex (better
appreciated in the limb leads). During atrial arrhythmias, drugs that block the AV node may
augment conduction down the accessory pathway, which lacks the normal decremental
conduction of the AV node. In atrial fibrillation or flutter, 1:1 conduction of atrial rates may
precipitate fatal ventricular fibrillation. In stable supraventricular tachycardia, adenosine may
precipitate atrial fibrillation and is best avoided. Of the drugs listed, procainamide has the least
action on the AV node; however, if procainamide is not readily available and the patient’s
hemodynamic stability is in question, amiodarone is a reasonable alternative.[3,8]
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A 15-year-old Asian male is brought in by paramedics after experiencing a seizure during gym
class. His 12-lead ECG is shown. The child has no history of seizure disorder, and he states that
he had palpitations before the seizure. The paramedics report that their 12-lead ECG in the field
was abnormal because their machine was reading it as acute myocardial infarction, but they were
unable to identify typical ST-segment elevations.
This ECG is consistent with which of the following abnormalities?
A. WPW syndrome
B. Brugada syndrome
C. Ebstein anomaly
D. Arrhythmogenic right ventricular cardiomyopathy
E. Yamaguchi syndrome
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Answer: B. Brugada syndrome
This ECG shows characteristic changes of Brugada syndrome, a sodium channelopathy
associated with the gene SCN5A (also implicated in long QT syndrome) that is more prevalent in
Asia. The ECG shows 1 of 2 ST-segment morphologies in V1-V3. The “coved” QRS (shown)
consists of a right bundle branch block morphology with a slowly downsloping ST segment (red
arrow) and an inverted T wave (blue arrow). The ST segment may also take a saddleback
appearance in these leads with an upright T wave. Only automatic implantable cardiac
defibrillators have been shown to prevent death from arrhythmias in patients with Brugada
syndrome. Urgent cardiologic evaluation should be arranged.[9]
18
A 15-year-old female is brought to the emergency department after an episode of syncope during
a long-distance running event. Her ECG obtained in the ED is shown. She has no previous ECGs
for comparison. She has no prior episodes of syncope, and she is on no medications. The family
reports that the child is adopted and her family history is unknown.
Until additional cardiac and genetic tests are performed, the child may be at the risk for a cardiac
event from:
A. Loud noises
B. Exercise
C. Sleep
D. Swimming
E. All of the above
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Answer: E. All of the above
The teenager has long QT syndrome, which results from several different ion channelopathies
involving cardiac sodium and potassium channels. Depending on the exact genetic abnormality
and ion channel involved, many triggers have been identified. The QTc interval in this ECG is
approximately 600 ms, which is well above the upper limit of normal for an adult female of 460
ms (440 ms for a male). The 98th percentile for QTc intervals of females of this age is 457 ms.
The markedly increased QT interval is also apparent when it is compared with the R-R interval
(shown); typically, QT intervals greater than one half of the R-R interval are considered to be
prolonged. Immediate referral for cardiologic evaluation is important.[3,10]
20
A 16-year-old female is referred to a pediatric cardiologist for evaluation after episodes of
exertional dyspnea and cyanosis. Her initial ECG is shown. Upon questioning, the mother reports
a normal birth history but states that the child was very colicky and fed poorly. She remembers
having to feed frequently for short periods for much of the first year of life. The patient has been
otherwise developing well since then.
What is the most likely diagnosis?
A. Bicuspid aortic valve
B. Left bundle branch block
C. Ebstein anomaly
D. Exercise-induced asthma
E. Long QT syndrome
21
Answer: C. Ebstein anomaly
This scenario is consistent with Ebstein anomaly, a congenital abnormality resulting in
enlargement and malformation of the tricuspid valve. Valve leaflets are displaced towards the
apex of the heart, and part of the right ventricle may become atrialized. The ECG shows marked
right-axis deviation with giant P waves (blue arrows) due to the enlarged right atrium. An rSr'
complex in V1 (red arrow) is consistent with a right ventricular conduction delay. Although
Ebstein anomaly is often diagnosed in childhood, many patients remain asymptomatic until
adulthood. Heart failure and arrhythmias are the main concerns for these patients, who ultimately
may require surgical intervention. Regular cardiologic follow-up is critical to good care.[3,11]
22
A 17-year-old male is brought in by advanced life support after acute onset of palpitations. He
denies having chest pain or shortness of breath but is anxious and very uncomfortable. He had no
known cardiac history, and this has never happened before. His blood pressure is 106/48 mm Hg
and stable. Amiodarone injection and rapid intravenous push of adenosine have not terminated
the rhythm.
What is the next appropriate step in management?
A. Synchronized cardioversion
B. Intravenous diltiazem
C. Intravenous metoprolol
D. Immediate defibrillation
E. Intravenous verapamil
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Answer: E. Intravenous verapamil
This patient has an acute episode of verapamil-sensitive idiopathic left ventricular tachycardia,
which is a class of recurrent, monomorphic ventricular tachycardias that occurs in young males
who have no gross structural abnormalities of the heart. The cause is typically a reentrant circuit
in the ventricular septum, particularly the left posterior fascicle. It is characterized by left-axis
deviation or, in some cases (such as this patient), extreme right-axis deviation as shown in leads I
and aVF. A characteristic right bundle branch block morphology is also present. Termination of
an acute episode is accomplished with verapamil, but long-term therapy often requires ablation
of the reentrant circuit. Long-term prognosis is generally benign.[12,13]
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Related Slideshows
Are You Missing an MI?
Can't-Miss ECG Findings, Life-Threatening Conditions
Subtle EKG Syndromes in Children and Adults
Six Abnormal ECGs — Not All Are Cases of the Heart

Other Slideshows
For More Information

Medscape Reference: Brugada Syndrome

Medscape Reference: Ebstein Anomaly

Medscape Reference: First-Degree Atrioventricular Block

Medscape Reference: Hypertrophic Cardiomyopathy

Medscape Reference: Junctional Rhythm

Medscape Reference: Long QT Syndrome
For More Information
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
Medscape Reference: Pediatric Hypertrophic Cardiomyopathy

Medscape Reference: Wolff-Parkinson-White Syndrome

Medscape Today: Electrocardiographic Manifestations: Pediatric ECG

ECG Wave Maven
Contributor Information
Authors
Michael S. Westrol, MD
House Staff
Department of Emergency Medicine
UMDNJ-Robert Wood Johnson Medical School
New Brunswick, New Jersey
Disclosure: Michael S. Westrol, MD, has disclosed no relevant financial relationships.
Raffi Kapitanyan, MD
Assistant Professor
Department of Emergency Medicine
UMDNJ-Robert Wood Johnson Medical School
New Brunswick, New Jersey
Disclosure: Raffi Kapitanyan, MD, has disclosed no relevant financial relationships.
Contributor Information
Editor
Lars Grimm, MD, MHS
House Staff
Department of Diagnostic Radiology
Duke University Medical Center
Durham, North Carolina
Disclosure: Lars Grimm, MD, MHS, has disclosed no relevant financial relationships.
Reviewer
Alan R. Morrison, MD/PhD
Cardiology Fellow
Yale-New Haven Hospital
New Haven, Connecticut
26
Disclosure: Alan R. Morrison, MD/PhD, has disclosed no relevant financial relationships.
Although most physicians are familiar with the normal limits of ECG intervals for adults, it may
not be immediately apparent that children have different normal values. Population studies have
helped to formulate generally accepted normal values for children at various ages,[1] which
should be referenced when interpreting an ECG. However, even with these values, it may be
difficult to make a diagnosis. Variation occurs in children depending on age and sex, but most
pathologic conditions fall well outside the range of normal. See whether you can determine
whether the ECGs in the following cases are benign variants from the norm or cause for concern.
Image courtesy of Wikimedia Commons.