Clinical Updates of Interest to Providers
COARCTATION OF THE AORTA - TIPS FOR EARLY DETECTION
Coarctation of the aorta (CoA), which has a male predominance, accounts for 8-10% of all
congenital heart disease. Over 50% of patients with CoA have a bicuspid aortic valve (the
most common congenital heart defect, occurring in 1 - 2% of people). Early detection of
coarctation is essential for effective treatment, as persistent systemic hypertension after
repair (even in the absence of persistent arch obstruction) is increasingly common the later in
life the treatment occurs.
Anatomy and Physiology. CoA usually results from an obstructing ridge in the lateral wall of
the descending thoracic aorta, across from the insertion of the patent ductus arteriosus (PDA)
(Figure 1). When the PDA is open, the obstruction is decompressed. When the PDA closes,
typically within several days to weeks, the degree of obstruction increases (Figure 2). When
the obstruction is severe, congestive heart failure occurs and infants may present in shock. In
this setting, echocardiography establishes the diagnosis early in life. When the obstruction is
less severe in infancy, CoA may not precipitate symptoms and remains clinically silent.
Diagnosis of CoA.
Femoral pulses: Even with significant aortic coarctation, femoral pulses will be palpable as
long as the aortic end pole of the PDA remains open (since the ductus closes from the
pulmonic to the aortic end, this process may take days or weeks after birth). This means a
neonate may have normal pulses during the early days of life (and during the hospital
discharge examination). Since femoral pulse patterns may change postnatally in patients with
CoA, examination of the femoral pulse should be an integral part of every pediatric
examination. Reduction in femoral pulse amplitude, delay of femoral pulse appearance
relative to the right radial pulse or absence of femoral pulses all are strong evidence of aortic
arch obstruction.
Tip #1: Include femoral pulse evaluation in every pediatric physical examination.
Blood pressure: Elevated blood pressure in the pre-coarctation branches of the aorta occurs
with significant arch obstruction. This means upper extremity (and carotid) blood pressure is
high, and lower extremity blood pressure is low and reduced in pulsatility. In many cases, the
origin of the left subclavian artery is narrowed by the coarctation, so pressure is obtained
best in the right arm. The American Academy of Pediatrics recommends routine blood
pressure measurement beginning at 3 years old.
Tip #2: Measure right arm blood pressure with the routine examination starting at 3 years of age.
Bicuspid aortic valve: Most patients with CoA have bicuspid aortic valves. The clinical hallmark
of the bicuspid aortic valve is a systolic ejection click, a distinct and snapping sound occurring
just after the 1st heart sound. The click is heard best over the cardiac apex and at the right
upper sternal border. The murmur associated with a CoA is often not prominent and, if
present, is often heard better over the back than the anterior chest.
Tip #3: If coarctation is suspected, listen carefully over the back and for an apical ejection click.
Chest X-ray: Occasionally, the configuration of the aortic arch on PA chest X-ray suggests
CoA. In older children, with ossified ribs, collateral vessels from the pre- to the post-coarcted
aorta run under the ribs, causing notching of their inferior borders.
Tip #4: Obtain a chest X-ray, alerting the radiologist to the possible presence of CoA.
Summary. Coarctation of the aorta must be suspected to be diagnosed. It is one of the
most “missed” congenital heart defects and can be difficult to diagnose. Pulse abnormalities
or hypertension should alert the physician to its possible presence. Listening for an aortic
ejection click or obtaining a chest X-ray may provide confirmatory information. With any
suspicion of this condition, referral for cardiac evaluation and echocardiography should be
made promptly, as early diagnosis is essential for optimal treatment. The adverse health
consequences of life long hypertension can sometimes be avoided by early diagnosis and
treatment.
POPULATION-BASED SUDDEN DEATH IN CHILDREN
Sudden death (SD) in children is a relatively uncommon but devastating problem. There are
few prospective population-based studies, and the annual incidence is poorly defined.
Existing retrospective death certificate–based studies suggest that the annual incidence of SD
in U.S. children ranges between 0.8 and 6.2 per 100,000 population. As part of the ongoing
Oregon Sudden Unexpected Death Study, the Oregon Health Sciences Center performed a
prospective, 3-year, community-wide, multiple-source evaluation of pediatric (0 – 17 years) SD
among the 660,486 residents of Multnomah County, Oregon (Heart Rhythm, Vol.6, Nov, 2009).
SD was defined as sudden unexpected collapse within 1 hour of symptom onset (witnessed),
or within 24 hours of being observed alive and symptom-free (unwitnessed). Subjects with a
non-cardiac terminal illness or SD associated with trauma, violent death, overdose, drowning,
or suicide were excluded. Thirty-three children (2.8% of the entire population) met criteria for
SD. The median age was 0.37 years, with an age range of 0.03–12.3 years. The pediatric SD
annual incidence was 1.7 per 100,000 total population or 7.5 per 100,000 children (ages 0 –
17). This compares to 60/100,000 for overall SCD among all ages. Of the SD victims, 25/33
were <1 year old and 23/25 met the criteria for SIDS. The other 2 were found to have
congenital heart disease (CHD) (interrupted aortic arch and VSD with LV noncompaction). Both
should have been detected by routine physical examination. Of the 8 children > 1 year old, 4
had a seizure disorder and 2 were found to have CHD (Ebstein’s + WPW and hypertrophic
cardiomyopathy). Information regarding the presenting rhythm was available in 22/33 (67%);
20/22 were found to be in asystole. In all likelihood, this does not represent the initial
malignant rhythm since SIDS cases, which represented the majority in this study, occurs at
times which result in a delay in emergency response. The authors concluded that SD in the
pediatric population is low (<3% of all SD), that the majority of cases are related to SIDS.
Children with CHD make up a significant proportion of this population.
TRICYCLIC ANTIDEPRESSANT (TCA) TOXICITY: STILL COMMON AFTER
ALL THESE YEARS
Case Presentation: A 16 year old girl presented to the emergency department with
somnolence, respiratory depression, hypotension, poor perfusion and tachycardia. A portion
of her ECG is shown. Although she was originally thought to be in ventricular tachycardia, a
history of purposeful TCA (nortryptyline) overdose was obtained from a parent and the
patient was appropriately managed with ventilatory support, intravenous hydration and
intravenous alkalinization with sodium bicarbonate. Within a few hours, her ECG started to
normalize and she made a full recovery.
Discussion: TCAs inhibit the reuptake of serotonin and epinephrine, block cardiac sodium
channels and phase 3 cardiac potassium channels, increase anticholinergic activity and
produce peripheral vascular α-adrenergic blockade. In toxic concentrations, the effects include
sinus tachycardia, significant cardiac conduction abnormalities (increased PR and QRS
durations), prolonged QT interval, ST segment and T-wave changes, hypotension, altered
mentation, seizures and the possibility of malignant and potentially fatal cardiac arrhythmias.
The classic electrocardiogram shows sinus tachycardia with long PR interval, wide QRS
duration, prolonged QT interval (which is what the above ECG shows; this is not ventricular
tachycardia) and a ‘classic’ large R wave in AVR (see above). A QRS duration >100ms predicts
a higher risk for ventricular arrhythmias and seizures and demands immediate attention.
There is no antidote for TCA overdose. Treatment includes rapid alkalinization of the serum to
a pH > 7.45, which counteracts the sodium channel blocking effects and quickly normalizes the
ECG. Fluid resuscitation, assisted ventilation and sedation to prevent seizures are utilized as
needed. Correct ECG interpretation is essential, since inappropriate use of antiarrhythmics
can easily increase sodium channel blockade (worsen conduction) and further prolong the QT
interval, thereby facilitating severe ventricular arrhythmias.
BREATH-HOLDING SPELLS AND SYNCOPE
Breath-holding spells (BHS), which occurs in 0.1 – 4.6% of young children based on recent
studies, is an involuntary, nonvolitional, reflexic, nonepileptic paroxysmal phenomenon of
childhood. Mild BHS, cyanosis without loss of consciousness, occurs in the majority of affected
children while severe BHS with syncope, with or without convulsions (sometimes referred to
as ‘Reflex Anoxic Syncope) is less common. Diagnosis is based on a distinctive and
stereotyped sequence of clinical events beginning with a provocation resulting in crying or
emotional upset that leads to a noiseless state of expiration accompanied by color change
and ultimately loss of consciousness and postural tone. Two clinical types are recognized
based on the child's coloration; cyanotic or pallid. Most children typically experience 1
predominate type, more often cyanotic than pallid, but some children may experience both
types. The episodes occur during full expiration despite its misnomer. Current data support
underlying autonomic dysregulation as a common mediating pathway, with sympathetic
overactivity in the case of cyanotic BHS and parasympathetic overactivity in the case of pallid
BHS. The natural history of the 2 types is not very different. BHS frequently has its first
appearance during the first 12 months of life. In 2 recent studies, 80% and 87% of patients
had their first symptoms before 18 months of age. A majority of children will experience
multiple episodes per week and up to one third will experience >1 episode per day at peak
frequency. Boys seem to have an earlier age at peak frequency (13-18 months) than do girls
(19-24 months). The mean age at resolution of symptoms is 36 to 42 months old. Several
authors have identified a tendency for BHS spells within family members. 20% to 35% of all
patients will have an identified family member who had suffered BHS at some time during their
childhood. Individuals with BHS have a greater likelihood of having neurally mediated (vaso-
vagal) syncope later in life. There is no specific treatment for BHS. It is generally considered
to be benign. An important part of evaluating children with BHS is parental counseling.
Accurate knowledge of the expected natural history can be reassuring and allay parental
anxiety.
COARCTATION OF THE AORTA - TIPS FOR EARLY DETECTION
Coarctation of the aorta (CoA), which has a male predominance, accounts for 8-10% of all
congenital heart disease. Over 50% of patients with CoA have a bicuspid aortic valve (the
most common congenital heart defect, occurring in 1 - 2% of people). Early detection of
coarctation is essential for effective treatment, as persistent systemic hypertension after
repair (even in the absence of persistent arch obstruction) is increasingly common the later in
life the treatment occurs.
Anatomy and Physiology. CoA usually results from an obstructing ridge in the lateral wall of
the descending thoracic aorta, across from the insertion of the patent ductus arteriosus (PDA)
(Figure 1). When the PDA is open, the obstruction is decompressed. When the PDA closes,
typically within several days to weeks, the degree of obstruction increases (Figure 2). When
the obstruction is severe, congestive heart failure occurs and infants may present in shock. In
this setting, echocardiography establishes the diagnosis early in life. When the obstruction is
less severe in infancy, CoA may not precipitate symptoms and remains clinically silent.
Diagnosis of CoA.
Femoral pulses: Even with significant aortic coarctation, femoral pulses will be palpable as
long as the aortic end pole of the PDA remains open (since the ductus closes from the
pulmonic to the aortic end, this process may take days or weeks after birth). This means a
neonate may have normal pulses during the early days of life (and during the hospital
discharge examination). Since femoral pulse patterns may change postnatally in patients with
CoA, examination of the femoral pulse should be an integral part of every pediatric
examination. Reduction in femoral pulse amplitude, delay of femoral pulse appearance
relative to the right radial pulse or absence of femoral pulses all are strong evidence of aortic
arch obstruction.
Tip #1: Include femoral pulse evaluation in every pediatric physical examination.
Blood pressure: Elevated blood pressure in the pre-coarctation branches of the aorta occurs
with significant arch obstruction. This means upper extremity (and carotid) blood pressure is
high, and lower extremity blood pressure is low and reduced in pulsatility. In many cases, the
origin of the left subclavian artery is narrowed by the coarctation, so pressure is obtained
best in the right arm. The American Academy of Pediatrics recommends routine blood
pressure measurement beginning at 3 years old.
Tip #2: Measure right arm blood pressure with the routine examination starting at 3 years of age.
Bicuspid aortic valve: Most patients with CoA have bicuspid aortic valves. The clinical hallmark
of the bicuspid aortic valve is a systolic ejection click, a distinct and snapping sound occurring
just after the 1st heart sound. The click is heard best over the cardiac apex and at the right
upper sternal border. The murmur associated with a CoA is often not prominent and, if
present, is often heard better over the back than the anterior chest.
Tip #3: If coarctation is suspected, listen carefully over the back and for an apical ejection click.
Chest X-ray: Occasionally, the configuration of the aortic arch on PA chest X-ray suggests
CoA. In older children, with ossified ribs, collateral vessels from the pre- to the post-coarcted
aorta run under the ribs, causing notching of their inferior borders.
Tip #4: Obtain a chest X-ray, alerting the radiologist to the possible presence of CoA.
Summary. Coarctation of the aorta must be suspected to be diagnosed. It is one of the
most “missed” congenital heart defects and can be difficult to diagnose. Pulse abnormalities
or hypertension should alert the physician to its possible presence. Listening for an aortic
ejection click or obtaining a chest X-ray may provide confirmatory information. With any
suspicion of this condition, referral for cardiac evaluation and echocardiography should be
made promptly, as early diagnosis is essential for optimal treatment. The adverse health
consequences of life long hypertension can sometimes be avoided by early diagnosis and
treatment.
POPULATION-BASED SUDDEN DEATH IN CHILDREN
Sudden death (SD) in children is a relatively uncommon but devastating problem. There are
few prospective population-based studies, and the annual incidence is poorly defined.
Existing retrospective death certificate–based studies suggest that the annual incidence of SD
in U.S. children ranges between 0.8 and 6.2 per 100,000 population. As part of the ongoing
Oregon Sudden Unexpected Death Study, the Oregon Health Sciences Center performed a
prospective, 3-year, community-wide, multiple-source evaluation of pediatric (0 – 17 years) SD
among the 660,486 residents of Multnomah County, Oregon (Heart Rhythm, Vol.6, Nov, 2009).
SD was defined as sudden unexpected collapse within 1 hour of symptom onset (witnessed),
or within 24 hours of being observed alive and symptom-free (unwitnessed). Subjects with a
non-cardiac terminal illness or SD associated with trauma, violent death, overdose, drowning,
or suicide were excluded. Thirty-three children (2.8% of the entire population) met criteria for
SD. The median age was 0.37 years, with an age range of 0.03–12.3 years. The pediatric SD
annual incidence was 1.7 per 100,000 total population or 7.5 per 100,000 children (ages 0 –
17). This compares to 60/100,000 for overall SCD among all ages. Of the SD victims, 25/33
were <1 year old and 23/25 met the criteria for SIDS. The other 2 were found to have
congenital heart disease (CHD) (interrupted aortic arch and VSD with LV noncompaction). Both
should have been detected by routine physical examination. Of the 8 children > 1 year old, 4
had a seizure disorder and 2 were found to have CHD (Ebstein’s + WPW and hypertrophic
cardiomyopathy). Information regarding the presenting rhythm was available in 22/33 (67%);
20/22 were found to be in asystole. In all likelihood, this does not represent the initial
malignant rhythm since SIDS cases, which represented the majority in this study, occurs at
times which result in a delay in emergency response. The authors concluded that SD in the
pediatric population is low (<3% of all SD), that the majority of cases are related to SIDS.
Children with CHD make up a significant proportion of this population.
TRICYCLIC ANTIDEPRESSANT (TCA) TOXICITY: STILL COMMON AFTER
ALL THESE YEARS
Case Presentation: A 16 year old girl presented to the emergency department with
somnolence, respiratory depression, hypotension, poor perfusion and tachycardia. A portion
of her ECG is shown. Although she was originally thought to be in ventricular tachycardia, a
history of purposeful TCA (nortryptyline) overdose was obtained from a parent and the
patient was appropriately managed with ventilatory support, intravenous hydration and
intravenous alkalinization with sodium bicarbonate. Within a few hours, her ECG started to
normalize and she made a full recovery.
Discussion: TCAs inhibit the reuptake of serotonin and epinephrine, block cardiac sodium
channels and phase 3 cardiac potassium channels, increase anticholinergic activity and
produce peripheral vascular α-adrenergic blockade. In toxic concentrations, the effects include
sinus tachycardia, significant cardiac conduction abnormalities (increased PR and QRS
durations), prolonged QT interval, ST segment and T-wave changes, hypotension, altered
mentation, seizures and the possibility of malignant and potentially fatal cardiac arrhythmias.
The classic electrocardiogram shows sinus tachycardia with long PR interval, wide QRS
duration, prolonged QT interval (which is what the above ECG shows; this is not ventricular
tachycardia) and a ‘classic’ large R wave in AVR (see above). A QRS duration >100ms predicts
a higher risk for ventricular arrhythmias and seizures and demands immediate attention.
There is no antidote for TCA overdose. Treatment includes rapid alkalinization of the serum to
a pH > 7.45, which counteracts the sodium channel blocking effects and quickly normalizes the
ECG. Fluid resuscitation, assisted ventilation and sedation to prevent seizures are utilized as
needed. Correct ECG interpretation is essential, since inappropriate use of antiarrhythmics
can easily increase sodium channel blockade (worsen conduction) and further prolong the QT
interval, thereby facilitating severe ventricular arrhythmias.
BREATH-HOLDING SPELLS AND SYNCOPE
Breath-holding spells (BHS), which occurs in 0.1 – 4.6% of young children based on recent
studies, is an involuntary, nonvolitional, reflexic, nonepileptic paroxysmal phenomenon of
childhood. Mild BHS, cyanosis without loss of consciousness, occurs in the majority of affected
children while severe BHS with syncope, with or without convulsions (sometimes referred to
as ‘Reflex Anoxic Syncope) is less common. Diagnosis is based on a distinctive and
stereotyped sequence of clinical events beginning with a provocation resulting in crying or
emotional upset that leads to a noiseless state of expiration accompanied by color change
and ultimately loss of consciousness and postural tone. Two clinical types are recognized
based on the child's coloration; cyanotic or pallid. Most children typically experience 1
predominate type, more often cyanotic than pallid, but some children may experience both
types. The episodes occur during full expiration despite its misnomer. Current data support
underlying autonomic dysregulation as a common mediating pathway, with sympathetic
overactivity in the case of cyanotic BHS and parasympathetic overactivity in the case of pallid
BHS. The natural history of the 2 types is not very different. BHS frequently has its first
appearance during the first 12 months of life. In 2 recent studies, 80% and 87% of patients
had their first symptoms before 18 months of age. A majority of children will experience
multiple episodes per week and up to one third will experience >1 episode per day at peak
frequency. Boys seem to have an earlier age at peak frequency (13-18 months) than do girls
(19-24 months). The mean age at resolution of symptoms is 36 to 42 months old. Several
authors have identified a tendency for BHS spells within family members. 20% to 35% of all
patients will have an identified family member who had suffered BHS at some time during their
childhood. Individuals with BHS have a greater likelihood of having neurally mediated (vaso-
vagal) syncope later in life. There is no specific treatment for BHS. It is generally considered
to be benign. An important part of evaluating children with BHS is parental counseling.
Accurate knowledge of the expected natural history can be reassuring and allay parental
anxiety.
 |
| |
 |
| |
 |
| |
 |
| |
 |
| |
 |
| |
 |
| |
 |
| |
 |
| |
 |
| PEDIATRIX CARDIOLOGY ASSOCIATES OF NEW MEXICO |
Figure 1. CoA with PDA
Figure 2. CoA with no PDA
Angiogram and CT of CoA