Download Congenital Heart Defects

CHD
ASD
PDA
VSD
Tetrology
of Fallot
Tricuspid Artesia
Transposition of great vessels
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Fetal Circulation
Oxygenated blood from Umb.
Vein bypasses liver and joins
deoxygenated blood via DV. >
Then it joins SVC and empties
in Rt atrium. > through PFO it
enters LA.
Blood enters aorta through DA
and bypasses pulm. Trunk
Some blood goes to RV but
through DA it again enters
aorta to bypass pulm. Trunk.
Deoxygenated blood returns
via umbilical arteries..
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Postnatal transition
With first breath, Increased
Alv. Pressure causes
vasodilation in pul. Vessels.
Obs. Clamping induces
constriction and changes UV
to Ligamentum teres and UA
to Medial umbilical ligaments.
DA becomes Ligamentum
arteriosum ( 10-15 minutes)
Foramen ovale closes and
becomes fossa ovalis
Causes of central cyanosis in the neonate
 Right-to-left shunt
1) Intracardiac level: cyanotic disease, anomalous systemic
venous connection to left atrium
2) Great vessel level: persistent pulmonary hypertension of
the newborn
3) Intrapulmonary level: pulmonary arteriovenous
malformation
Ventilation/perfusion mismatch
1) Airway disease: pneumonia, aspiration, cystic
adenomatoid malformation, diaphragmatic hernia,
pulmonary hypoplasia, labor emphysema, atelectasis,
pulmonary hemorrhage, hyaline membrane disease,
transient tachypnea of the newborn
2) Extrinsic compression of lungs: pneumothorax, pleural
effusion, chylothorax, hemothorax, thoracic dystrophy
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Alveolar hypoventilation
 Central nervous system depression: asphyxia, maternal sedation,
intraventricular hemorrhage, seizure, meningitis, encephalitis
 Neuromuscular disease: Werdnig-Hoffman disease, neonatal
myasthenia gravis, phrenic nerve injury
 Airway obstruction: choanal atresia, laryngotracheomalacia,
macroglossia, Pierre Robin syndrome
Hemoglobinopathy: Methemoglobinemia: congenital or secondary to
toxic exposure Other hemoglobinopathies
Diffusion impairment
 Pulmonary edema: left-sided obstructive cardiac disease,
cardiomyopathy, Pulmonary fibrosis, Congenital lymphangiectasia
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More than 32,000 infants (one out of every 125 to 150) are born
with heart defects each year in the United States
1% of newborn affected by CHD
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The development of the cardiovascular system … Begins to develop toward the end of the third week
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The critical period of heart development is from day 20 to day 50
after fertilization.
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Three shunts in the fetal circulation
1)Ductus arteriosus
2) Ductus Venosus
3) Foramen Ovale
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Signs and symptoms suspicious for neonatal congenital
heart disease
Poor feeding: bottle feedings longer than 20 to 30
minutes, taking too little volume, resting frequently during
feeds, or otherwise unexplained choking, gagging and/or
frequent vomiting with feeds
Breathing too fast or hard, particularly increasing with
feeds
Persistent unexplained cough or wheeze
Color changes: central cyanosis, persistent pallor, grey,
Excessive sweating, even while sleeping, increasing with
feeds and other exertion
Excessive, unexplained irritability
Decreased activity; increased or excessive sleepingPoor
weight gain
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Most frequent Congenital heart
anomalies
Patent Ductus arterious
Transposition of great vessels
Hypoplastic left heart syndrome
Tetrology of Fallots
Pulmonary atresia
Classification
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Cyanotic CHD
Infants unable to achieve
PaO2 of 100 % after inspiring
of 100 % O2.
Cyanosis
Murmur
CXR and ECG
If PaO2 is low start PGE1
infusion.
TOF, TA, Transposition,
Truncus Arteriorus,
TAPVR,HLHS
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Acyanotic CHD
Infants will able to achieve
PaO2 of > 100 % in same
condition
Murmur
Symptoms of CHF
Treatment vary from
observation, PGE1 infusion to
treatment of arrythmia
ASD, VSD, PDA, HLHS, Coarc
of aorta, av canal
Transposition of great vessles
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Most common, M:F> 2: 1
P/E
CXR- Egg on stick appearance
Echo
Catheterization- diagnostic and often therapeutic
Treatment: if sever hypoxia of acidosis occurs, urgent
atrial balloon septostomy and subsequent arterial switch
operation is done
Tetrology of Fallots
( PS, RVH, Overriding aorta, VSD)
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Male predominance
P/E
CXR- boot shaped heart with decreased pul.
Vascular markings.
EKG
Echo-diagnostic
Tt: If Pul. Flow is ductal dependent will benefit
from PGE1 infusion
Acyanotic Heart Diseases
100 % O2 test
 Murmur
 Signs of CHF
 VSD, ASD, PDA, HLHS
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VSD
Most common
 Spontaneous closure in Half of the
patients
 M:F > 1:1
 Takes upto 4 wks to develop CHF
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ASD
Mostly closes
spontaneously
May develop CHF but not
in neonatal period
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PDA
Large vessel connects
pul. Trunk with
descending aorta.
Persistent patency of fetal
channel after birth
Closure in utero may lead
to fetal demise of PHT
Factors associated with PDA
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Associated with Increased
incidence
Prematurity
45 % in BW < 1750 gms
80 % in BW < 1000 gms
RDS and surfactant treatment
Fluid administration: Increased
iv fluid load in first few days of
life > increased incidence of
PDA
Asphyxia
Congenital syndromes
High altitude
As a part of CHD
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Associated with
Decreased
incidence
Antenatal steroid
administration
IUGR
PROM
Clinical signs and presentation of
PDA
Murmur
 Bounding pulses and increased pulse
pressure
 Hypotension
 Respi deterioration
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Diagnosis
and Mx
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Diagnosis
Echo
Radiologic signs
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Mx
Ventilatory support
Fluid Restriction
Increase HCt
Indomethacin
Ibuprofen
Surgery
Cx and C/I of Indomethacin
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Cx
Renal Defects(
transient decrease in
GFR)
GI bleeding
Platelet function
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C/I of indomethacin
S. Creatinine> 1.7
Frank GI or renal
Bleeding
NEC
Sepsis
Arterial blood gas
• A blood gas measurement on an arterial sample should be obtained in any
newborn with cyanosis.
•An arterial PO2 value provides more specific data than oxygen saturation.
•Because of the increased affinity of fetal hemoglobin for oxygen, PO2 values
at a given level of oxygen saturation are often lower in newborns than adults.
•An elevated arterial PCO2 value often indicates the presence of pulmonary
disease. PCO2 may also be increased in heart failure.
•A reduced pH level raises concern about poor cardiac output. The
combination of severe hypoxemia, metabolic acidosis, and marked
hypercarbia may occur in patients with d-transposition of the great arteries
when there is inadequate mixing at the levels of the atria, ventricles, and great
vessels.
•Patients with methemoglobinemia typically have low oxygen saturation and
normal oxygen tension., the blood has a chocolate-brown color
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Hyperoxia test
The hyperoxia test is useful in distinguishing cardiac from pulmonary
causes of cyanosis.
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In CHD associated with intracardiac right-to-left shunting, blood in
the pulmonary veins is fully saturated with oxygen in ambient air.
Administering higher concentrations of inspired oxygen increases
the amount of dissolved oxygen but has minimal effect on oxygen
tension levels. In contrast, patients with pulmonary disease have
pulmonary venous desaturation. Supplemental oxygen
administration in pulmonary disease typically increases pulmonary
venous oxygen levels and improves systemic oxygenation.
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The preductal oxygen tension while breathing 100 percent oxygen
concentration rarely exceeds 150 mmHg in cyanotic heart disease,
and usually exceeds this value in pulmonary disease
Mx
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General approach — The initial approach includes cardiorespiratory support and
monitoring. If there is respiratory compromise, an adequate airway should be
established immediately and supportive therapy (eg, oxygen, mechanical ventilation)
instituted as needed. Patients with hypotension or poor perfusion require
cardiopulmonary resuscitation.
Antibiotics — Sepsis can lead to cyanosis and left ventricular dysfunction or
pulmonary disease. As a result, unless another specific etiology is promptly identified,
broad spectrum antibiotics should be initiated (ampicillin and gentamicin) after
obtaining a complete blood count, urinalysis, and blood and urine cultures.
Prostaglandin E1 — An infant who fails the hyperoxia test and does not have
persistent pulmonary hypertension of the newborn or a chest radiograph consistent
with lung disease is likely to have a congenital heart defect that is dependent upon
the ductus arteriosus for pulmonary or systemic blood flow. If metabolic acidosis is
present or if timely echocardiography is not available, prostaglandin E1 should be
administered until a definitive diagnosis is established. This is usually started as an
intravenous infusion in a dose of 0.05 µg/kg per minute
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DEFINITION — Cyanosis is a bluish discoloration of the
tissues that results when the absolute level of reduced
hemoglobin in the capillary bed exceeds 3 g/dL [6-8].
The appearance of cyanosis depends upon the total
amount of reduced hemoglobin rather than the ratio of
reduced to oxygenated hemoglobin.
Two mechanisms result in an increased concentration of
reduced hemoglobin in the capillary bed that in turn
leads to cyanosis: increased oxygen extraction by the
tissues and systemic arterial oxygen desaturation. Based
upon these mechanisms, two types of cyanosis are
described, peripheral and central.
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Central cyanosis — Central cyanosis, the focus of this topic review,
is a pathologic condition caused by reduced arterial oxygen
saturation. It involves highly vascularized tissues, such as the lips
and mucous membranes, through which blood flow is brisk and the
arteriovenous difference is minimal. Cardiac output typically is
normal, and patients have warm extremities.
Peripheral cyanosis — Patients with peripheral cyanosis have a
normal systemic arterial oxygen saturation and increased oxygen
extraction, resulting in a wide systemic arteriovenous oxygen
difference. The increased extraction of oxygen results from sluggish
movement of blood through the capillary circulation. Causes include
vasomotor instability, vasoconstriction caused by exposure to cold,
venous obstruction, elevated venous pressure, polycythemia, and
low cardiac output.
Peripheral cyanosis affects the distal extremities and circumoral or
periorbital areas [6]. The extremities are often cool or clammy.
Peripheral cyanosis may be associated with sepsis but is also seen
in normal newborns, especially those with fair complexions.
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ETIOLOGY — Hypoxemia, with decreased arterial
oxygen saturation leading to central cyanosis, results
from the following mechanisms (show table 1) [6]:
Right-to-left shunting at the intracardiac, great vessel, or
intrapulmonary level
Ventilation-perfusion mismatch
Alveolar hypoventilation
Hemoglobinopathy (including methemoglobinemia) that
limits oxygen transport (show figure 3) [11]
Diffusion impairment
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Noncardiac causes — Many noncardiac abnormalities can lead to
cyanosis. (See "Suspected heart disease in the newborn: Criteria for
referral").
Pulmonary disorders are the most common causes and include structural
abnormalities of the lung, ventilation-perfusion mismatching, congenital or
acquired airway obstruction, pneumothorax, and hypoventilation.
Abnormal forms of hemoglobin (eg, methemoglobin, show table 2) can
result in cyanosis, and polycythemic infants may appear cyanotic even if
they are adequately oxygenated. (See "Genetic disorders of hemoglobin
oxygen affinity" and see "Neonatal polycythemia").
Poor peripheral perfusion may result from sepsis, hypoglycemia,
dehydration, and hypoadrenalism.
Right-to-left shunting through the ductus arteriosus, resulting in a differential
between SaO2 measured in the arm (preductal) and leg (postductal), can
occur with primary or persistent pulmonary hypertension
Cardiac causes — Cardiac causes of central cyanosis
have been classified using different systems
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A frequently used mnemonic is the "five Ts" of cyanotic CHD:
Transposition of the great arteries
Tetralogy of Fallot
Truncus arteriosus
Total anomalous pulmonary venous connection
Tricuspid valve abnormalities.
A sixth "T" is often added for "tons" of other diseases, such as double outlet
right ventricle, pulmonary atresia, multiple variations of single ventricle,
hypoplastic left heart syndrome, complex conditions associated with
heterotaxy syndromes, or anomalous systemic venous connection (left
superior vena cava connected to the left atrium).
We find that a more useful classification of cyanosis separates the defects
into physiologic categories based upon decreased pulmonary blood flow,
increased pulmonary blood flow, or severe heart failure.
Autosomal dominant
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Albright hereditary osteodystrophyCardiomyopathy
Ehlers-DanlosRupture of large vessels
Holt-OramASD, VSD
LeopardPS, prolonged PR interval
MarfanAortic aneurysm, AI, MVP
Myotonic dystrophyCardiomyopathy
NeurofibromatosisCOA, renal artery stenosis
Osler-Weber-RenduMultiple telangiectasis, pulmonary AVF
Treacher CollinsASD, VSD, PDA
Tuberous sclerosisMyocardial rhabdomyoma, WPW
NoonanPS, ASD, AS, subaortic stenosis
Autosomal recessive inheritance
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CarpenterPDA
CockayneAtherosclerosis
Cutis laxaPulmonary hypertension
Cystic fibrosisCor pulmonale
Ellis-van CreveldASDFriedreich ataxiaCardiomyopathy
HomocystinuriaThromboses
MPS type I H (Hurler)Coronary artery disease,
AI,
MIMPS type I S (Scheie)Aortic valve disease
MPS type IV (Morquio)Aortic valve disease
MPS type VI (Maroteaux-LamyAortic valve diseasePompe disease
(acid maltase deficiency, GSD type 2)Cardiomyopathy
Pseudoxanthoma elasticumCoronary artery disease, MIRefsum
diseaseArrhythmiaSmith-Lemli-OpitzVSD,PDAThrombocytopenia
absent radii (TAR)ASD, TOF
X-linked inheritence
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(Hunter)Coronary artery disease, valvular
diseaseDuchenne muscular
dystrophyCardiomyopathyEmery-Dreifuss
muscular dystrophy
CardiomyopathyIncontinentia
pigmentiPDA, hypertensionFabry
diseaseCoronary artery disease