Overview Of Congenital Heart Disease

Runal Shah

MEM-PGY1

KDAH, Mumbai

Fetal Cardio-vascular circulation

• Congenital heart disease (CHD) is the most common congenital

disorder in newborns.

• Critical CHD, defined as lesions requiring surgery or catheter based

intervention in the first year of life,

• One of the leading causes of infant mortality.

• Urgent consultation/referral to a pediatric cardiologist

• In patients with ductal-dependent cardiac lesions and profound

cyanosis, Prostaglandin E1 (Alprostadil) Infusion To Maintain Patency

of Ductus Arteriosus

Neonates <28 days old: 0.05-0.1 mcg/kg/min IV initially; usual

maintenance ranges from 0.01-0.4 mcg/kg/min

Preferably administer via large vein; alternatively, administer through

umbilical artery catheter (S/E Apnea)

Duct – dependent lesions

• The affected neonate may not be symptomatic during the birth

hospitalization because the Ductus Arteriosus has not yet closed

prior to discharge.

• The lesions that were not diagnosed prior to discharge were primarily

ductal dependent and included :

Coarctation of the aorta (COA)

Interrupted aortic arch

Aortic stenosis

Hypoplastic left heart syndrome (HLHS)

Transposition of the great arteries

• with ductal-dependent lesion, may appear normal with either

no or very subtle signs and symptoms during the birth

hospitalization.

• As a result, the diagnosis of critical CHD may be missed prior

to discharge.

• In these infants, closure of the Ductus arteriosus may

precipitate rapid clinical deterioration that may be life-

threatening.

Duct Dependent Circulation

To Supply Systemic Circulation :

• Interrupted Aortic Arch

• CoA

• HLHS

To Supply Pulmonic Circulation :

• Critical PS

• Pulmonary Atresia

• Severe Ebstein Anomaly

For Mixing of Circulation :

• TGA with Intact IVS

Shock

• In Left heart obstructive lesions (e.g., HLHS, Critical AS, CoA, and

Interrupted AA), systemic perfusion is lost.

• In Right-sided obstructive lesions (e.g., TAPVC, TA, and Mitral Atresia),

restricted pulmonary blood flow results in reduced systemic blood

flow, which may result in shock.

• In lesions with parallel pulmonary and systemic circulations (e.g.,

TGA with intact ventricular septum), mixing between the two

circulations is decreased, leading to hypoxia and metabolic acidosis,

which results in failure and shock.

Cyanosis

• Cyanosis is the bluish discoloration of the skin that occurs from the presence of deoxygenated hemoglobin (which is blue) in capillary beds.

• For cyanosis to be clinically apparent, 3 to 5 milligrams/dL of Deoxyhemoglobin must be present, corresponding to an oxygen saturation of 70% to 80% on room air.

• Congenital heart defects that present with cyanosis include TGA, TOF, TA, Truncus arteriosus, and TAPVR.

• These lesions have in common the mixing of Oxygenated and Deoxygenated blood, circulation of Desaturated hemoglobin, and a cardinal manifestation as Cyanotic heart disease.

• Another condition resulting in cyanosis is persistent fetal circulation, which can be caused by structural heart disease or Noncardiacdisease, including Meconium aspiration, pneumonia, sepsis, and pulmonary hypertension.

Cyanosis in Nonductal-dependent congenital

heart defects :

Total anomalous pulmonary venous connection (TAPVC).

Truncus arteriosus.

• Lesions may or may not be ductal dependent depending upon the

degree of outflow tract obstruction including tetralogy of Fallot and

tricuspid atresia.

• Other lesions may exhibit differential cyanosis, such as critical

Coarctation of the aorta or interrupted arch, where the deoxygenated

flow through the ductus supplies the lower half of the body's

circulation, but oxygenated blood flow from the left heart supplies

the upper body via the vessels proximal to the site of arch

obstruction.

Cyanosis

Severe Pulmonary Edema

• Pulmonary edema, resulting in tachypnea and increased work of

breathing, can occur when there is a massive, rapid increase in

pulmonary blood flow associated with a fall in pulmonary vascular

resistance at delivery.

• In conditions such as Truncus arteriosus or PDA in premature infants,

or pulmonary venous circulation obstruction in total anomalous

pulmonary venous connection with obstruction.

Vitals

• Pulse : Abnormal heart rate — In infants with heart rates that are

higher or lower than the normal range of 90 to 160 beats per minute

for neonates up to six days of age, electrocardiography is initially

performed to determine whether there is an arrhythmia.

• Respiratory rate : Tachypnea (>40/min)

Screening according to AAP,AHA,ACCF (1 out of 3) :

1) SpO2 measurement <90 percent

2) SpO2 measurement <95 percent in both upper and lower extremities

on three measurements, each separated by one hour

3) SpO2 difference >3 percent between the upper and lower extremities

On Examination

CVS Auscultation

• Split S2

• Early systolic clicks

• Mid-systolic clicks

• S3 gallop

• Pericardial friction rubs

• Murmurs Innocent / Pathologic/ Absent

Peripheral Pulses Examination & BP diff > 10 mm of Hg

Coughing & Wheezing : Pulm. Vs. Cardiac involvement

History

• Maternal and prenatal history

Preterm infants (gestational age <37 weeks): CHD is two to three

times that found in term infants

• Maternal conditions that increase the risk of neonatal CHD

include the following:

Diabetes, obesity, hypertension, CHD – refer to family history, Thyroid

conditions

Epilepsy and mood disorders

Maternal fever or influenza

Smoking in the first trimester

Congenital complete heart block in offspring of mothers with

connective tissue disorders and anti-Ro/SSA and anti-

La/SSB antibodies.

Congenital infections such as cytomegalovirus, herpesvirus, rubella,

or coxsackie virus.

• Drugs taken in pregnancy such as

Hydantoin PS, AS

Lithium Ebstein's anomaly

Alcohol ASD, VSD

• Assisted reproductive technology (ART) increases the risk for

congenital heart disease, particularly for malformations of the

outflow tracts and ventriculo-arterial connections. It is unclear if this

risk is related to the underlying etiology of infertility in the couple or

the ART per se.

• Family history — There is an overall threefold increased risk for CHD

when a first degree relative has CHD. The familial risk of specific

malformations is even greater, suggesting a stronger genetic effect

in these conditions

Reference:

http://www.uptodate.com/contents/congenital-heart-disease-chd-in-

the-newborn-presentation-and-screening-for-critical-chd#H3215187

Tintinalli’s Emergency Medicine A Comprehensive Study Guide, 7th

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