89: Congenital Heart Disease

INTRODUCTION

The diagnostic dilemma of the newborn with congenital heart disease must be resolved quickly because therapy may prove lifesaving for some of these infants. Congenital heart disease occurs in ∼1% of live-born infants. Nearly half of all cases of congenital heart disease are diagnosed during the first week of life. In patients with complex congenital heart disease, neonatal hospital mortality can be as high as 7%. These patients have a high frequency of multiple congenital anomalies, syndromes, low birthweight, and prolonged length of stay. The most frequently occurring anomalies seen during this first week are patent ductus arteriosus (PDA), D-transposition of the great arteries, hypoplastic left heart syndrome (HLHS), tetralogy of Fallot (TOF), and pulmonary atresia.

I. CLASSIFICATION

Symptoms and signs in newborns with heart disease permit grouping according to levels of arterial oxygen saturation based on the 100% oxygen test (see the following). Further classification (based on other physical findings, laboratory testing) facilitates delineation of the exact cardiac lesion present.

1. Cyanotic heart disease. Infants with cyanotic heart disease are usually unable to achieve a Pao₂ of >100 mm Hg after breathing 100% inspired oxygen for 10–20 minutes (hyperoxia test).

2. Acyanotic heart disease. Infants with acyanotic heart disease achieve Pao₂ levels of >100 mm Hg under the same conditions as noted in Section I.A.

II. CYANOTIC HEART DISEASE

See Figure 89–1. (See Chapter 51.)

1. Hyperoxia test. Because of intracardiac right-to-left shunting, the newborn with cyanotic congenital heart disease (in contrast to the infant with pulmonary disease) is unable to raise the arterial saturation, even in the presence of increased ambient oxygen.

   1. Determine Pao₂ while the infant is on room air.

   2. Give 100% oxygen for 10–20 minutes by mask, hood, or endotracheal tube.

   3. Obtain an arterial blood gas level while the infant is breathing 100% oxygen.

   4. Interpret results based on Section I.

2. Cyanosis. Care must be taken in evaluating cyanosis by skin color because polycythemia, jaundice, racial pigmentation, or anemia may make clinical recognition of cyanosis difficult. See Infectious.

3. Murmur. The infant with cyanotic congenital heart disease often does not have a distinctive murmur. The most serious of these anomalies may not be associated with a murmur at all.

4. Other studies. Cyanotic infants may be further classified on the basis of pulmonary circulation on chest radiograph and electrocardiographic findings.

5. Diagnosis and treatment. Figure 89–1 outlines the diagnosis and treatment of cyanotic heart disease.

6. Specific cyanotic heart disease abnormalities

   1. D-transposition of the great arteries (D-TGA). This is the most common cardiac cause of cyanosis in the first year of life, with a male-to-female ratio of 2:1. The aorta comes from the right ventricle and the pulmonary artery from the left ventricle, with resultant separate systemic and pulmonary circuits. With modern newborn care, the 1-year survival rate is ∼90%.

      1. Physical examination. Typical infant ...