Congenital Heart Disease in the Emergency Department

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Context and Definition

Congenital heart disease (CHD) accounts for 10% of all congenital anomalies. In the developed world, it is one of the most common causes of death in the first year of life. Usually, CHD is diagnosed in utero or in the newborn nursery, however, some critical lesions do not manifest until 1 to 2 weeks of life, when the ductus arteriosus closes.

Many of these conditions require immediate intervention. About 25% of children are born with critical and potentially fatal forms of congenital heart disease.

It should be notedthat even those who have undergone surgical corrections may have residual deficits making them susceptible to acute illness.

Typically, infants with previously undiagnosed structural CHD initially present in the emergency department (ED) with the following;

A ) Cyanosis

B ) Congestive heart failure (CHF)

C ) Cardiogenic shock or circulatory collapse

A) Cyanotic or blue baby

These are referred to as the terrible T’s or the horrible H’s. Cyanosis results from decreased pulmonary perfusion, or from complete mixing of systemic and pulmonary venous return in the heart.

  • Tetralogy of Fallot
  • Transposition of great arteries (TGA)
  • Total anomalous pulmonary venous return (TAPVR)
  • Truncus arteriosus
  • Tricuspid atresia
  • Hypoplastic left heart syndrome
  • Hypoplastic right heart conditions

B ) Congestive heart failure (CHF):

Usually, left-sided obstructive lesions present with shock as the ductus arteriosus closes and the blood supply to the systemic circulation diminishes. The examples are as follows:

  • Coarctation of the aorta
  • Congenital aortic stenosis
  • Hypoplastic left heart syndrome
  • Total anomalous pulmonary venous return with obstruction (resulting in volume overload of the right ventricle)

C) Cardiogenic shock or circulatory collapse

  • Critical coarctation of the aorta
  • Interrupted aortic arch
  • Congenital aortic stenosis
  • Hypoplastic left heart syndrome

For clinical purposes cyanotic lesions can be classified based on the pulmonary blood flow

I ) Decreased Pulmonary blood flow (Right to Left Shunting): associated with obstruction to pulmonary blood flow

  • Tetralogy of Fallot
  • Tricuspid Atresia
  • Pulmonary Atresia

II) Increased Pulmonary blood flow (Intracardiac mixing): not associated with obstruction to pulmonary blood flow

  • Total Anomalous Pulmonary Venous Return
  • Truncus arteriosus
  • Transposition of the Great Arteries
  • Hypoplastic Left Heart Syndrome

Definition

CHD is defined as structural heart disease present at birth. It is relatively common and affects around 1% of all newborns (actual incidence of 8 per 1000 live births).

Potential outcome

The outcome for an infant with CHD depends on the type and severity of the defect as well as the presence of extra-cardiac malformations which are common in this group of children. The more complex, cyanotic defects generally have a worse prognosis. Without surgical intervention, many of these are associated with death in infancy without surgical treatment. Those who have successfully undergone surgery usually remain well through childhood; but the prognosis in adult life depends on the type and severity of the condition, as well as the magnitude of any residual lesions.

The role of the clinician

  • Rapid and thorough assessment
  • Consider alternate diagnoses: excluding non-cardiac causes such as sepsis, congenital adrenal hyperplasia etc.
  • The first step in the evaluation is to determine whether the cyanosis is central or peripheral.
  • If cyanosis is central perform hyperoxia test; since it helpsto distinguish cardiac from pulmonary causes of cyanosis
  • Administer 100% oxygen for 10 minutes (hyperoxia), and then obtain a post-ductal blood sample for arterial blood gas analysis.
  • Pa O2 > 150 mm Hg is suggestive of a pulmonary cause
  • Pa O2 < 150 mm Hg then suspect a cardiac cause
  • Chest Radiograph: Provides assessment of heart size, pulmonary vascular markings, and aortic arch-sidedness

Heart Size

  • Increased heart size: left-sided obstructive lesions
  • Congenital aortic stenosis
  • Interrupted aortic arch
  • Critical coarctation of the aorta

Pulmonary vascular marking

  • “Black out” appearance: Decreased Pulmonary blood flow
  • Tetralogy of Fallot
  • Tricuspid Atresia
  • Pulmonary Atresia
  • “White out” appearance: Increased pulmonary blood flow or pulmonary venous obstruction
  • Total Anomalous Pulmonary Venous Return
  • Truncus arteriosus
  • Transposition of the Great Arteries
  • Hypoplastic Left Heart Syndrome

 

  • TGA: egg-on-a-string appearance
  • Tetralogy of Fallot: Boot-shaped heart
  • Snowman appearance: TAPVR

Aortic arch sidedness

  • Left-sided aortic arch: Normal
  • Right-sided aortic arch: tetralogy of Fallot, TGA, and truncus arteriosus