**6.3.3.1 Chest x-ray**

Chest film appearance is, by and large, dependent upon the total pulmonary blood flow. In patients with diminished pulmonary blood flow (the majority of infants fall into this group), the heart size is either normal or minimally enlarged. Several patterns of cardiac configuration have been described but in the author's experience and that of others, there is no consistent pattern that would be diagnostic of TA. There may be concavity in the region of pulmonary artery segment in patients with pulmonary oligemia and small pulmonary artery. The right atrial shadow may be prominent. In patients with increased pulmonary blood flow, cardiomegaly and prominent pulmonary vasculature are seen.

#### **6.3.3.2 Electrocardiogram**

The ECG can be virtually diagnostic of tricuspid atresia in an infant with cyanotic CHD. The characteristic features include right atrial enlargement, an abnormal, superiorly oriented major QRS vector (so called left axis deviation) in the frontal plane, left ventricular hypertrophy and diminished right ventricular forces. Abnormally superior vector (left axis deviation) is present in excess of 80% of patients with type I (normally related great vessels) anatomy while only less than 50% of patients with type II (transposition) anatomy show such a typical electrocardiographic pattern.

#### **6.3.3.3 Echocardiogram**

38 Congenital Heart Disease – Selected Aspects

Infants with pulmonary plethora usually present with signs of heart failure within the first few weeks of life although an occasional infant may present within the first few days of life. They are only minimally cyanotic, but present with symptoms of dyspnea, fatigue, difficulty to feed, and perspiration. Recurrent respiratory tract infections and failure to thrive are other modes of presentation. The majority of these patients belong to type II (transposition with a large VSD) although a small number of patients may be of type Ic (no transposition but a large VSD). The association of aortic coarctation with type II patients has already been mentioned and coarctation, when present, makes them vulnerable to early cardiac failure.

In infants (and children) with pulmonary oligemia, physical examination reveals central cyanosis, clubbing (in older infants and children), tachypnea or hyperpnea, normal pulses, prominent "a" wave in the jugular venous pulse (if there is inter-atrial obstruction), and no hepatic enlargement. Quiet precordium, and absence of thrills are usual. The second heart sound is usually single. A holosystolic murmur suggestive of VSD may be heard at the left lower or mid sternal border. No diastolic murmurs are heard. In patients with associated pulmonary atresia, no murmurs are usually heard, although in an occasional patient a continuous murmur of PDA may be heard. Signs of clinical congestive heart failure are

In the group with pulmonary plethora, examination reveals tachypnea, tachycardia, decreased femoral pulses (if associated with CoA), minimal cyanosis and hepatomegaly. Prominent "a" waves in the jugular veins and/or presystolic hepatic pulsations may be observed with associated inter-atrial obstruction. The second heart sound may be single or split. A holosystolic murmur of VSD is usually heard at the left lower sternal border. An apical mid-diastolic flow murmur may be heard. Clear-cut signs of congestive heart failure

Chest film appearance is, by and large, dependent upon the total pulmonary blood flow. In patients with diminished pulmonary blood flow (the majority of infants fall into this group), the heart size is either normal or minimally enlarged. Several patterns of cardiac configuration have been described but in the author's experience and that of others, there is no consistent pattern that would be diagnostic of TA. There may be concavity in the region of pulmonary artery segment in patients with pulmonary oligemia and small pulmonary artery. The right atrial shadow may be prominent. In patients with increased pulmonary

The ECG can be virtually diagnostic of tricuspid atresia in an infant with cyanotic CHD. The characteristic features include right atrial enlargement, an abnormal, superiorly oriented major QRS vector (so called left axis deviation) in the frontal plane, left ventricular hypertrophy and diminished right ventricular forces. Abnormally superior vector (left axis deviation) is present in excess of 80% of patients with type I (normally related great vessels) anatomy while only less than 50% of patients with type II (transposition) anatomy show

blood flow, cardiomegaly and prominent pulmonary vasculature are seen.

**6.3.2 Physical findings** 

notably absent.

are usually present.

**6.3.3.1 Chest x-ray** 

**6.3.3.2 Electrocardiogram** 

such a typical electrocardiographic pattern.

**6.3.3 Non-invasive evaluation** 

The echo is reasonably characteristic for TA. Two-dimensional echocardiography, apart from showing enlarged right atrium, left atrium, and left ventricle and a small right ventricle, will demonstrate the atretic tricuspid valve directly. In the most common muscular type, a dense band of echoes is seen at the site where the tricuspid valve should be and the anterior leaflet of the detectable atrioventricular valve is attached to the left side of the inter-atrial septum. Apical and subcostal four-chambered views are best to demonstrate the anatomy. Atrial and ventricular septal defects can also be demonstrated by 2-D echocardiography and shunting across these defects can be demonstrated by Doppler echocardiography. Semilunar valves can be identified as pulmonary or aortic by following the great vessel until the bifurcation of the pulmonary artery or arch of the aorta is seen, this will help decide whether there is associated transposition of the great arteries. Measurement of peak Doppler flow velocities across the VSD and right ventricular outflow tract will not only reveal if obstruction is present at these sites but will also allow estimation of pulmonary artery pressures. Suprasternal notch imaging will be of use in demonstrating CoA, which is often seen in type II (transposition) patients. Contrast echocardiography with two-dimensional imaging will clearly demonstrate sequential opacification of the right atrium, left atrium, left ventricle and then the right ventricle. However, such a study is not always necessary for diagnosis.

#### **6.3.4 Cardiac catheterization and selective cineangiography**

The diagnosis of TA based on clinical, electrocardiographic, and echocardiographic features is relatively simple, and cardiac catheterization and selective cineangiography, rarely, if ever, are essential for arriving at the diagnosis. However, these procedures are useful and should be undertaken to resolve issues not clarified by non-invasive studies and to evaluate multiple physiologic and anatomic features prior to planned Fontan-Kreutzer operation (Rao 1992).

Oxygen saturation data reveal diminished systemic venous saturation; the extent of decrease is related to the systemic arterial desaturation and the severity of congestive heart failure. The pulmonary venous saturation is usually in the normal range. A significant decrease in left atrial saturation is expected because of obligatory right-to-left shunting across the patent foramen ovale. Falsely high or falsely low saturations may be measured in the left atrium because of streaming. The left ventricular saturations are usually well mixed and are more reliable. The saturations in the left atrium, left ventricle and aorta as well as those in the right ventricle and pulmonary artery are nearly equal. Systemic arterial (aortic) desaturation is always present and the extent of desaturation is proportional to the Qp:Qs.

The right atrial pressure may be mildly increased. If the foramen ovale is restrictive the pressure in the right atrium is markedly elevated; a mean pressure gradient of 5 mmHg across the patent foramen ovale in favor of the right atrium and giant "a" waves in the right atrium are indicative of an obstructive foramen ovale. The left atrial mean and left ventricular end-diastolic pressures are usually normal, but may be elevated if there is increased pulmonary blood flow, poor left ventricular function or significant mitral insufficiency. The right ventricular pressure is proportional to the size of the VSD in type I (normally related great arteries) patients while it is at systemic level in type II (transposition) patients. Systolic pressure gradient across the VSD may be seen if it is restrictive. The pulmonary artery pressure may be normal or increased depending upon the size of the VSD

Congenital Heart Defects – A Review 41

symptoms, pulmonary artery banding should then be considered. Alternatively, an absorbable band may be used (Rao 2001). By contrast, in type II (transposition) patients, banding of the pulmonary artery should be performed once the infant is stabilized with

In infants with evidence for interatrial obstruction, balloon and/or blade atrial septostomy

Following initial palliation, the children should be followed under close cardiologic supervision. Currently, preferred "corrective" procedure is staged total cavopulmonary anastomosis. A bi-directional Glenn procedure (superior vena cava to pulmonary artery anastomois) may be performed around the age of six months. Preoperative catheter evaluation to define the pulmonary artery pressure and anatomy and to exclude a persistent left superior vena cava (because it may divert blood away from the pulmonary arteries) prior to bidirectional Glenn surgery should be undertaken. At the time of bidirectional Glenn procedure, stenoses, if any, of the pulmonary artery should be repaired. Issues related

When the patients reach the age and size (approximately 15 Kg) suitable for Fontan-Kreutzer operation, diversion of inferior vena caval blood into the pulmonary artery either by a lateral tunnel or extracardiac conduit is recommended. At the present time extracardiac conduit diversion of inferior vena caval blood into the pulmonary artery) is preferred by most surgeons.. Immediately prior to Fontan conversion, cardiac catheterization should be undertaken to ensure normal anatomy and pressure of the pulmonary artery as well as normal left ventricular end-diastolic pressure. At the same time, aortopulmonary collaterals should be evaluated by means of selective subclavian artery and descending thoracic aortic angiography. If collateral vessels are present, they should be occluded with coils or devices,

In patients with transposition of the great arteries, early pulmonary artery banding, treatment of aortic coarctation, and relieving or bypassing subaortic obstruction should also

If the patient has risk factors for poor outcome (for e.g., elevated pulmonary pressure/resistance, pulmonary artery distortion, and left ventricular dysfunction) for the corrective procedure, a fenestrated Fontan procedure should be considered. Some surgeons prefer fenestration for all patients. Six to twelve months later, transcatheter closure of the

Close follow-up after correction is indicated. While most of these patients will do well, some may develop arrhythmia (atrial flutter or fibrillation, paroxysmal supraventricular tachycardia), obstructed Fontan pathways, branch pulmonary artery stenosis, thromboembolism, persistent right to left shunts (Fontan fenestrations or atrial septal defects), systemic venous to pulmonary venous collateral vessels and protein-losing enteropathy.

Congenital heart defect is an anatomic malformation of the heart and/or great vessel, which occurs during intrauterine development. The incidence of CHD is 0.6 to 0.8% of live-births. The exact etiology of CHD is not known and the majority of cardiac defects can be explained by multifactorial inheritance hypothesis. The CHD may be classified as acyanotic and cyanotic defects and the former is further divided into obstructive and left-to-right shunt

fenestration may be undertaken if the fenestration did not spontaneously close.

Detailed evaluation of these problems and appropriate treatment is mandatory

anticongestive measures. If there is associated CoA, it should also be relieved.

to subaortic obstruction and mitral valve regurgitation should also be addressed.

may be necessary.

as appropriate.

**7. Conclusions** 

be incorporated into the treatment plan.

(and associated PS) in type I patients and upon the presence or absence of subvalvar or valvar PS in type II patients. Aortic pressures are usually normal. If CoA is present, systolic hypertension and pressure gradient across the coarctation will be present.

Of all the calculated values, Qp:Qs and pulmonary vascular resistance are most useful. The Qp:Qs is diminished in type I hypoxemic patients with small or no VSD while it is markedly increased in type I patients with moderate to large VSDs and in most patients with type II anatomy. Pulmonary vascular resistance is an important factor to be taken into consideration for deciding to go ahead with Fontan-Kreutzer operation; elevated resistance adversely affects the outcome of the operation.

Selective right atrial angiography will confirm the diagnosis. Following right atrial injection, successive opacification of the left atrium and left ventricle without direct opacification of the right ventricle occurs and this negative shadow of the unopacified right ventricle, the so called right ventricular window is considered characteristic for TA. Selective left ventricular angiography is also recommended and is useful in evaluating its size and function, size and type of VSD, anatomy and size of the right ventricle, relationship of the great arteries and the source of pulmonary blood flow. Selective right ventricular and pulmonary arterial angiograms are possible with the currently available catheter/guide wire technology and may be necessary in some cases for better definition prior to considering "corrective" surgical procedures.

#### **6.3.5 Management**

Physiologically "corrective" operation for TA, namely, Fontan-Kreutzer procedure and its modifications, have improved the prognosis of patients with tricuspid atresia. Such physiologic correction is usually performed in patients older than 2 years. As stated above, most patients with TA present with symptoms in the neonatal period and should be effectively palliated to enable them to reach the age at which surgical correction could be undertaken. The objective of any management plan, apart from providing symptomatic relief and increased survival rate, should be to preserve, protect, and restore anatomy (good sized and undistorted pulmonary arteries) and physiology (normal pulmonary artery pressures and preserved left ventricular function) to normal such that a "corrective" procedure could later be performed safely.

Medical management of the neonate, just as for TGA patients, includes maintenance of neutral thermal environment, normal acid-base status, normoglycemia and normocalcemia by appropriate monitoring and correction, if needed. No more than 0.4 FI02 is necessary unless there is associated pulmonary pathology.

In neonates with low arterial PO2 and O2 saturation with ductal dependent pulmonary blood flow, the ductus should be kept open by intravenous infusion of PGE1, in doses similar to that described in TOF and TGA sections. Once the infant is stabilized and appropriate diagnostic studies are performed, a Blalock-Taussig type of shunt is performed in the group with pulmonary oligemia.

In neonates and infants with pulmonary plethora and congestive heart failure, aggressive anticongestive therapy must be instituted. In type I (normally related great arteries) patients, the natural history of the VSD is such that it closes spontaneously and the infants will go on to develop pulmonary origemia (Rao 1977b). Because of these reasons, it is recommended that banding of the pulmonary artery not be routinely performed in this group of patients. If optimal anticongestive therapy with some delay does not produce adequate relief of

(and associated PS) in type I patients and upon the presence or absence of subvalvar or valvar PS in type II patients. Aortic pressures are usually normal. If CoA is present, systolic

Of all the calculated values, Qp:Qs and pulmonary vascular resistance are most useful. The Qp:Qs is diminished in type I hypoxemic patients with small or no VSD while it is markedly increased in type I patients with moderate to large VSDs and in most patients with type II anatomy. Pulmonary vascular resistance is an important factor to be taken into consideration for deciding to go ahead with Fontan-Kreutzer operation; elevated resistance

Selective right atrial angiography will confirm the diagnosis. Following right atrial injection, successive opacification of the left atrium and left ventricle without direct opacification of the right ventricle occurs and this negative shadow of the unopacified right ventricle, the so called right ventricular window is considered characteristic for TA. Selective left ventricular angiography is also recommended and is useful in evaluating its size and function, size and type of VSD, anatomy and size of the right ventricle, relationship of the great arteries and the source of pulmonary blood flow. Selective right ventricular and pulmonary arterial angiograms are possible with the currently available catheter/guide wire technology and may be necessary in some cases for better definition prior to considering "corrective"

Physiologically "corrective" operation for TA, namely, Fontan-Kreutzer procedure and its modifications, have improved the prognosis of patients with tricuspid atresia. Such physiologic correction is usually performed in patients older than 2 years. As stated above, most patients with TA present with symptoms in the neonatal period and should be effectively palliated to enable them to reach the age at which surgical correction could be undertaken. The objective of any management plan, apart from providing symptomatic relief and increased survival rate, should be to preserve, protect, and restore anatomy (good sized and undistorted pulmonary arteries) and physiology (normal pulmonary artery pressures and preserved left ventricular function) to normal such that a "corrective"

Medical management of the neonate, just as for TGA patients, includes maintenance of neutral thermal environment, normal acid-base status, normoglycemia and normocalcemia by appropriate monitoring and correction, if needed. No more than 0.4 FI02 is necessary

In neonates with low arterial PO2 and O2 saturation with ductal dependent pulmonary blood flow, the ductus should be kept open by intravenous infusion of PGE1, in doses similar to that described in TOF and TGA sections. Once the infant is stabilized and appropriate diagnostic studies are performed, a Blalock-Taussig type of shunt is performed

In neonates and infants with pulmonary plethora and congestive heart failure, aggressive anticongestive therapy must be instituted. In type I (normally related great arteries) patients, the natural history of the VSD is such that it closes spontaneously and the infants will go on to develop pulmonary origemia (Rao 1977b). Because of these reasons, it is recommended that banding of the pulmonary artery not be routinely performed in this group of patients. If optimal anticongestive therapy with some delay does not produce adequate relief of

hypertension and pressure gradient across the coarctation will be present.

adversely affects the outcome of the operation.

procedure could later be performed safely.

in the group with pulmonary oligemia.

unless there is associated pulmonary pathology.

surgical procedures.

**6.3.5 Management** 

symptoms, pulmonary artery banding should then be considered. Alternatively, an absorbable band may be used (Rao 2001). By contrast, in type II (transposition) patients, banding of the pulmonary artery should be performed once the infant is stabilized with anticongestive measures. If there is associated CoA, it should also be relieved.

In infants with evidence for interatrial obstruction, balloon and/or blade atrial septostomy may be necessary.

Following initial palliation, the children should be followed under close cardiologic supervision. Currently, preferred "corrective" procedure is staged total cavopulmonary anastomosis. A bi-directional Glenn procedure (superior vena cava to pulmonary artery anastomois) may be performed around the age of six months. Preoperative catheter evaluation to define the pulmonary artery pressure and anatomy and to exclude a persistent left superior vena cava (because it may divert blood away from the pulmonary arteries) prior to bidirectional Glenn surgery should be undertaken. At the time of bidirectional Glenn procedure, stenoses, if any, of the pulmonary artery should be repaired. Issues related to subaortic obstruction and mitral valve regurgitation should also be addressed.

When the patients reach the age and size (approximately 15 Kg) suitable for Fontan-Kreutzer operation, diversion of inferior vena caval blood into the pulmonary artery either by a lateral tunnel or extracardiac conduit is recommended. At the present time extracardiac conduit diversion of inferior vena caval blood into the pulmonary artery) is preferred by most surgeons.. Immediately prior to Fontan conversion, cardiac catheterization should be undertaken to ensure normal anatomy and pressure of the pulmonary artery as well as normal left ventricular end-diastolic pressure. At the same time, aortopulmonary collaterals should be evaluated by means of selective subclavian artery and descending thoracic aortic angiography. If collateral vessels are present, they should be occluded with coils or devices, as appropriate.

In patients with transposition of the great arteries, early pulmonary artery banding, treatment of aortic coarctation, and relieving or bypassing subaortic obstruction should also be incorporated into the treatment plan.

If the patient has risk factors for poor outcome (for e.g., elevated pulmonary pressure/resistance, pulmonary artery distortion, and left ventricular dysfunction) for the corrective procedure, a fenestrated Fontan procedure should be considered. Some surgeons prefer fenestration for all patients. Six to twelve months later, transcatheter closure of the fenestration may be undertaken if the fenestration did not spontaneously close.

Close follow-up after correction is indicated. While most of these patients will do well, some may develop arrhythmia (atrial flutter or fibrillation, paroxysmal supraventricular tachycardia), obstructed Fontan pathways, branch pulmonary artery stenosis, thromboembolism, persistent right to left shunts (Fontan fenestrations or atrial septal defects), systemic venous to pulmonary venous collateral vessels and protein-losing enteropathy. Detailed evaluation of these problems and appropriate treatment is mandatory
