**4.2.3 Noninvasive evaluation**

#### **4.2.3.1 Chest roentgenogram**

In most cases, the chest X-ray shows a normal sized heart and a dilated ascending aorta; the latter is a sign of post-stenotic dilatation. In neonates and those with very severe heart failure cardiomegaly is seen.

#### **4.2.3.2 Electrocardiogram**

The ECG may be normal or may show varying degrees of left ventricular hypertrophy. Inverted T waves in the left chest leads indicate that aortic valve obstruction is severe. However, not all severe AS patients show T wave inversion.

None of the above described clinical and laboratory data have any predictive value in determining the severity of aortic valve obstruction.

#### **4.2.3.3 Echocardiogram**

The echocardiogram may show thickened and domed aortic valve leaflets. The aortic valve is usually bicuspid (Figure 5), with eccentric opening.

The left ventricular muscle may be thickened and its shortening fraction may be increased, depending upon the severity of AS. Doppler flow velocity across the aortic valve is increased and can be used to quantitate peak instantaneous gradient across the aortic valve in a manner similar to that described for the pulmonary valve. However, Doppler-derived mean systolic gradient appears to reflect peak-to-peak catheter gradient (see below) more accurately than peak instantaneous Doppler gradient. Mild degree of aortic insufficiency

the aortic valve leaflets so frequent in the elderly is uncommon during childhood. Dilatation of ascending aorta, post-stenotic dilatation, is seen in most cases, and the extent of aortic dilatation is independent of the severity of aortic obstruction. Hypertrophy of the left ventricular muscle is concentric in nature and is largely proportional to the degree of

The majority of children with valvar AS are asymptomatic and the AS is detected because of a cardiac murmur heard on routine auscultation. When symptoms are exhibited, dyspnea, easy fatigability or chest pain is presenting complaint. Syncope may be a presenting complaint in some children with severe AS. In contradistinction to children, neonates and

The left ventricular impulse is increased (left ventricular heave) in all but mild cases. A thrill may be felt at the right upper sternal border and/or in the supra-sternal notch. The first heart sound is usually normal. The second heart sound is also normal unless the aortic stenosis is extremely severe when there may be a paradoxical splitting of the second heart sound. An ejection systolic click is heard best at the apex and left mid and right upper sternal borders and the click does not vary with respiration. An ejection systolic murmur of grade II-V/VI intensity is usually heard best at the right upper sternal border with radiation

In most cases, the chest X-ray shows a normal sized heart and a dilated ascending aorta; the latter is a sign of post-stenotic dilatation. In neonates and those with very severe heart

The ECG may be normal or may show varying degrees of left ventricular hypertrophy. Inverted T waves in the left chest leads indicate that aortic valve obstruction is severe.

None of the above described clinical and laboratory data have any predictive value in

The echocardiogram may show thickened and domed aortic valve leaflets. The aortic valve

The left ventricular muscle may be thickened and its shortening fraction may be increased, depending upon the severity of AS. Doppler flow velocity across the aortic valve is increased and can be used to quantitate peak instantaneous gradient across the aortic valve in a manner similar to that described for the pulmonary valve. However, Doppler-derived mean systolic gradient appears to reflect peak-to-peak catheter gradient (see below) more accurately than peak instantaneous Doppler gradient. Mild degree of aortic insufficiency

young infants usually present with dyspnea and signs of heart failure.

into both carotid arteries. The arterial pulses are usually normal.

However, not all severe AS patients show T wave inversion.

determining the severity of aortic valve obstruction.

is usually bicuspid (Figure 5), with eccentric opening.

obstruction.

**4.2.1 Symptoms** 

**4.2.2 Physical findings** 

**4.2.3 Noninvasive evaluation 4.2.3.1 Chest roentgenogram** 

failure cardiomegaly is seen. **4.2.3.2 Electrocardiogram** 

**4.2.3.3 Echocardiogram** 

may be seen by color Doppler, even in patients without auscultatory evidence for aortic regurgitation.

Fig. 5. Short axis views of the aorta showing aortic valve leaflets in closed (a) and open position (b) in children with tricuspid aortic valves (a and b). Bicuspid aortic valve (large arrows) is shown in c, which is commonly associated with aortic stenosis. Three aortic valve cusps and commissures ( in a) are clearly seen and contrast with two valve cusps and single horizontal commissure (in c). Arrow heads in b point to open aortic valve leaflets. Neither of the children showed clinical or echo-Doppler evidence for aortic stenosis and are shown here only to demonstrate the bicuspid and tricuspid valve leaflets. LA, left atrium; RA, right atrium; RV, right ventricle.

### **4.2.4 Cardiac catheterization and angiography**

The data show elevated left ventricular peak systolic pressure with a peak-to-peak pressure gradient across the aortic valve indicative of the severity of obstruction. Angiography will confirm thickened domed aortic valve leaflets and exclude any other abnormalities.

#### **4.2.5 Management**

The indications for intervention in valvar AS is a peak-to-peak gradient >50 mmHg with either symptoms or electrocardiographic ST-T wave changes or a peak gradient >70 mmHg irrespective of symptoms or ECG changes (Rao 1989b, Rao 1990). When pressure gradients are used as criteria for intervention (instead of valve area), it must be assured that the cardiac index is normal during pressure measurement. Until recently, surgical commissurotomy was the treatment of choice. Since the introduction of balloon valvuloplasty for valvar AS in 1983, increasing number of pediatric cardiologists, including the author of this chapter have been using balloon aortic valvuloplasty as a first therapeutic procedure for relief of aortic valve obstruction although, at this time, there is no consensus with regard to the choice of treatment mode. When surgical commissurotomy is chosen it is usually performed on cardiopulmonary bypass. When balloon valvuloplasty is performed, a

Congenital Heart Defects – A Review 13

subclavian artery) are present in the majority of patients with CoA; this hypoplasia may be significant in symptomatic CoA of the neonate and infant, whereas in older children there may be only a mild degree of narrowing. The most commonly associated defects are patent ductus arteriosus, ventricular septal defect and AS. The younger the infant presents, the more likely that there is a significant associated defect. Bicuspid aortic valve and abnormal mitral valve are also seen. Sometimes, CoA is a complicating feature of a more complex, cyanotic heart defects, such as transposition of the great arteries, Taussig-Bing anomaly, double-inlet left ventricle, tricuspid atresia with transposition of the great arteries, and hypoplastic left heart syndrome. In this section, I will discuss CoA in children older than 1

Children beyond infancy usually are asymptomatic; an occasional child will complain of pain or weakness in the legs. Most often, the coarctation is detected because of a murmur or

A clinical diagnosis of CoA is best made by simultaneous palpation of femoral and brachial pulses. The left ventricular impulse may be increased. A thrill is usually felt in the suprasternal notch. The first and second heart sounds are usually normal in isolated aortic coarctation. Since a large percentage (up to 60%) of patients with CoA have associated bicuspid aortic valves, an ejection systolic click may be heard at right upper and left mid sternal borders and apex; this click does not change with respiration. An ejection systolic murmur may be heard at left or right upper sternal borders, but is usually heard best over the back in the inter-scapular regions. Sometimes a continuous murmur may be heard in the left inter-scapular region secondary to continuous flow in the coarcted segment or on the back (secondary to flow in the collateral vessels). Palpation of the brachial and femoral artery pulses simultaneously will reveal delayed and decreased or absent femoral pulses. Blood pressure in both arms and one leg must be determined: a peak systolic pressure difference of more than 20 mmHg in favor of arms may be considered as evidence for coarctation of the aorta (Rao 1995). Involvement of the left subclavian artery in the coarctation or anomalous origin of the right subclavian artery (below the level of coarctation) may produce decreased or absent left or right brachial pulses, respectively, and therefore palpation of both brachial pulses and measurement of blood pressure in both arms

Chest roentgenogram may show a normal sized heart or the heart may be mildly enlarged. Other roentgenographic features include a "3" sign on a highly penetrated chest x-ray, inverted "3" sign of the barium filled esophagus and rib-notching (secondary to collateral

The ECG may be normal or may show left ventricular hypertrophy.

hypertension which is detected on a routine examination (Rao 1995).

year of age.

**4.3.1 Symptoms** 

are important.

vessels).

**4.3.3.1 Chest x-ray** 

**4.3.3 Noninvasive evaluation** 

**4.3.3.2 Electrocardiogram** 

**4.3.2 Physical findings** 

balloon diameter size 80% to 100% of the size of the aortic valve annulus is chosen for valvuloplasty (Rao 1990). Immediate, short-term and long-term results following balloon aortic valvuloplasty (Figure 6) are encouraging. Only limited long-term results are available to-date (Galal et al 1997, Rao 1999).

Fig. 6. Bar graph showing maximum peak instantaneous Doppler gradients, indicative of severity of aortic stenosis, prior to (Pre), one day following (Post) balloon aortic valvuloplasty and at intermediate-term (ITFU) and late (LTFU) follow-up. Note significant reduction (p 0.001) after valvuloplasty, which continues to be lower (p 0.001) at ITFU and LTFU.

For milder forms of AS, subacute bacterial endocarditis prophylaxis and periodic follow-up are necessary. Restriction from participation in competitive sports is recommended for all but mildest form of AS.

#### **4.3 Coarctation of the aorta**

The prevalence of coarctation of the aorta (CoA) was found to vary between 5% and 8% of CHDs; however, coarctation may be found more frequently in infants presenting with symptoms prior to one year of age. In the past, CoA was designated as preductal (or infantile) or postductal (or adult) type, depending on whether the coarctation segment was proximal or distal to the ductus arteriosus, respectively. However, a closer examination of the anatomy suggests that all coarctations are juxtaductal. The coarctation may be discrete, or a long segment of the aorta may be narrowed; the former is more common. Classic CoA is located in the thoracic aorta distal to the origin of the left subclavian artery, at about the level of the ductal structure. However, rarely, a coarcted segment may be present in the abdominal aorta. Varying degrees of hypoplasia of the isthmus of the aorta (the portion of the aorta between the origin of the left subclavian artery and the ductus arteriosus) and transverse aortic arch (the arch between the origin of the innominate artery and the left subclavian artery) are present in the majority of patients with CoA; this hypoplasia may be significant in symptomatic CoA of the neonate and infant, whereas in older children there may be only a mild degree of narrowing. The most commonly associated defects are patent ductus arteriosus, ventricular septal defect and AS. The younger the infant presents, the more likely that there is a significant associated defect. Bicuspid aortic valve and abnormal mitral valve are also seen. Sometimes, CoA is a complicating feature of a more complex, cyanotic heart defects, such as transposition of the great arteries, Taussig-Bing anomaly, double-inlet left ventricle, tricuspid atresia with transposition of the great arteries, and hypoplastic left heart syndrome. In this section, I will discuss CoA in children older than 1 year of age.
