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Clinical and hemodynamic bases of the roentgen findings in cyanotic congenital heart disease
Clinical and Hemodynamic Bases of the Roentgen Findings in Cyanotic Congenital Heart Disease By SAMUEL KAPLAN,
M.D.
I
N THE MAJORITY OF PATIENTS with cyanotic congenital heart disease, a presumptive diagnosis of the functional derangement can be made on the basis of clinical, electrocardiographic and roentgenographic features. However, the precise anatomic details and the physiologic consequences of specific anomalies generally require specialized studies, including selective angiocardiography as well as measurement of blood flow, direction of shunt, and intravascular pressures and resistance. The purpose of this paper is to suggest the clinical and electrocardiographic information that may be of value in the interpretation of roentgen findings. INC~ENCE
The incidence and type of cyanotic congenital heart disease vary in each age group, with the highest mortality occurring in the first year of life. In the neonatal period, transposition of the great vessels, hypoplastic left heart syndrome, and severe forms of Fallot’s tetralogy (with pulmonary arterial hypoplasia or atresia) comprise more than 75 per cent of all symptomatic patients. Prior to the widespread use of palliative therapy for transposition of the great vessels, the majority of these babies succumbed during the first 6 months of life. However, the success of, balloon septostomy’ or excision of the atria1 septum1 with or without pulmonary artery banding6 has increased the prevalence of arterial transposition in older infants and young children. In this age group most patients with cyanotic congenital heart disease now have either Fallot’s tetralogy or transposition of the great vessels. The more common types of cyanotic congenital, heart disease in adolescents and adults are the Eisenmenger’s physiology (bidirectional or right-to-left shunt across a VSD, ASD or PDA) and Fallot’s tetralogy, usually with a functioning surgical systemic-pulmonary artery anastomosis. Less frequent types of cyanotic congenital heart disease encountered in infancy include anomalies of pulmonary and systemic venous return, tricuspid atresia or stenosis with underdeveloped right ventricle, isolated pulmonic stenosis with right-to-left shunt across the atria1 septum, single ventricle with puhnonic stenosis or transposition,, endocardial cushion defect with pulmonic stenosis, double outlet right ventricle with pulmonic stenosis, and pulmonary atresia with intact ventricular septum. In this age group, cyanosis may be produced by pulmonary hypertension due to elevated pulmonary arteriolar From the Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio. Supported in part by USPHS Grants HE05728 and HE02427. SAMUEL KAPLAN, M.D.: Professor of Pediatrics and Associute Professor of Medicine, University of Cincinnati College of Medicine; Director, Division of Cardiology, Children’s Hospital, Cincinnati, Ohio. SEMINARSIN ROENTGENOLOGY, VOL. 3, No. 4 (OCTOBER), 1968
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KAPLAN
resistance or pulmonary venous hypertension. Ebstein’s anomaly, truncus arteriosus with decreased pulmonary blood flow and pulmonary arteriovenous fistula may be seen in any age group. CYANOSIS
Generally, at least 5 Gm. of reduced hemoglobin per 100 ml. of circulating blood must be present before cyanosis can be appreciated clinically. Therefore, if the cyanotic patient’s hemoglobin is 15 Gm. per cent, one third or more is in the form of reduced hemoglobin. The normal arterial oxygen saturation is about 95 per cent and mixed systemic venous blood at rest is about 70 to 75 per cent saturated. It is known that 1 ml. of oxygen is taken up by 0.75 Cm. hemoglobin or 1 Gm. of hemoglobin takes up 1.33 ml. of oxygen. Thus, in an individual with 15 Gm. per cent of hemoglobin the oxygen capacity is about 20 volumes per cent ( 15 x 1.33). Generally the more intense the cyanosis the more severe the polycythemia and digital clubbing. The volume of venoarterial or right-to-left shunt (central cyanosis) is the most important factor in determining the amount of reduced hemoglobin in arterial blood. Cyanosis is evident because arterial unsaturation results in a low capillary oxygen saturation and a further decrease in the oxygen content of venous blood. The greater the volume of right-to-left shunt, the more intense is the cyanosis. The volume of pulmonary blood flow and the adequacy of intracardiac mixing are also important factors in determining the degree of cyanosis. Severe pulmonic stenosis decreases pulmonary blood flow and the amount of hemoglobin available for oxygenation. This is particularly true in Fallot’s tetralogy in which the right-to-left shunt across the VSD is increased during exercise because of the relatively fixed right ventricular outflow obstruction and pulmonary blood flow. However, isolated pulmonic stenosis with intact ventricular and atria1 septum is not associated with cyanosis unless heart failure supervenes. Inadequacy of intracardiac mixing is seen especially in arterial transposition with intact ventricular septum. In spite of increased pulmonary blood flow in these patients, cyanosis is intense because a sufhcient amount of oxygenated blood is unable to reach the systemic circulation, However, when adequate intracardiac mixing of pulmonic and systemic venous blood occurs in the presence of a torrential pulmonary flow, cyanosis is absent or minimal. Examples of these circumstances include truncus arteriosus with large pulmonary arteries and excessive pulmonary flow, total anomalous pulmonary venous return without pulmonary venous obstruction, and Taussig-Bing anomaly in infants. In these patients, arterial unsaturation is mild and mixed venous blood is highly saturated so that the arteriovenous oxygen difference is small. Peripheral cyanosis is seen in patients whose tissue oxygen utilization is increased. Although the arterial saturation is normal, excessive extraction of oxygen by the tissues results in a large arteriovenous oxygen difference. This is seen in some patients with congestive heart failure and decreased cardiac output. Differential cyanosis is of great value in diagnosis and depends on perfusion of the lower thoracic and abdominal aorta with blood from the pulmonary
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artery via a PDA. The line of demarcation is at the level of the brim of the pelvis since the chest and abdominal wall are supplied by branches of the subclavian artery (internal mammary and superficial epigastric) which arise above the entry of the ductus into the aorta. In severe pulmonary hypertension associated with PDA, with or without aortic coarctation or interruption of the aortic isthmus, the lower extremities are blue since they are perfused with unsaturated blood from the pulmonary artery. In some patients, with pulmonary hypertension and PDA but without coarctation, pulmonary arterial blood may also enter the left subclavian artery, causing cyanosis of the left arm as well. Transposition of the great vessels and PDA, with or without aortic coarctation, may be associated with perfusion of the lower thoracic aorta with arterialized blood via the pulmonary artery, so that the lower extremities are pinker than the upper portion of the body. Some patients with hypoplastic left heart syndrome and a minute opening in the aortic valve have an unusual distribution of cyanosis.? Since left ventricular ejection is preferential to the innominate artery, the right upper quadrant of the body is relatively pink and the rest of the body is cyanotic. CLINICAL
Hypercyanotic
SIGNS
Attacks (Anoxic or Blue Spells)
Unpredictable attacks of paroxysmal dyspnea are a serious problem in infants and are of grave prognostic significance. They are seen most frequently with severe tetralogy of Fallot but are not pathognomonic of this disease. These spells have also been occasionally described in infants with pulmonary stenosis and intact ventricular septum, tricuspid atresia and underdeveloped right ventricle, and arterial transposition with intact ventricular septum. The disappearance or attenuation of the systolic murmur and the reduction of arterial oxygen saturation and pulmonary artery pressure during an episode suggest that the anoxic spells in Fallot’s tetralogy are associated with right ventricular outflow spasm. Guntheroth et al.’ suggested that hyperpnea precipitates the attacks. Systemic venous return is increased during hyperpnea. When the pulmonary blood flow is fixed or decreased, the right-to-left shunt is increased. The resultant arterial hypoxia, metabolic acidosis and increased carbon dioxide tension further stimulate respiration and the hyperpnea continues. Cerebral
Thrombosis
This occurs especially in the first 2 years of life. Since the viscosity of blood is increased by polycythemia, this complication is more frequent in malformations associated with severe cyanosis. Thus, cerebrovascular accidents are more often seen in patients with Fallot’s tetralogy, arterial transposition and tricuspid atresia. Brain Abscess
Although less than 1 per cent of patients with congenital heart disease suffer from this complication, about 10 per cent of patients with brain abscess have underlying congenital heart disease.” Since brain abscess rarely occurs before the age of 2, infants with cyanotic congenital heart disease and neurologic signs
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are usually suffering from cerebral thrombosis. Cerebral abscess is seen almost exclusively in patients with cyanotic congenital heart disease and right-to-left shunt, although there are isolated reports of its occurrence in the usual forms of ASD and VSD. Cerebral abscess has been recorded in patients with Fallot’s tetralogy, arterial transposition, Eisenmenger’s complex, tricuspid atresia, truncus arteriosus, Ebstein’s anomaly and single ventricle. Distant sites of infection are demonstrated in 40 per cent” so that the abscess is presumably seeded either by an infected “paradoxical” embolus or bacteremia. Bacterial
Endocarditis
At Children’s Hospital, the commonest underlying cardiovascular lesion which is complicated by bacterial endocarditis is Fallot’s tetralogy with a functioning systemic-pulmonary artery anastomosis. Bacterial endocarditis has been encountered on 11 occasions in 9 patients out of a group of 30 with Fallot’s tetralogy and Potts anastomosis. Since bacterial endocarditis occurs less frequently after a Blalock-Taussig operation, it is probable that the near normal arterial oxygen saturation produced by the larger pulmonary blood flow which occurs after the Potts operation plays an important role in the development of the bacterial endocarditis. VENOUS PULSE AND PRESSURE
Inspection of the venous pressure is accomplished by observing the pulsation of the internal jugular vein with the patient lying comfortably with his head and shoulders propped to an angle of about 45 degrees. Since valves are absent in the superior vena caval system, venous pulsations are produced by pressure fluctuations in the right atrium. These changes occur with tricuspid or pulmonic valve disease, decreased right ventricular compliance, increased right ventricular end-diastolic pressure and severe pulmonary hypertension. In patients with tricuspid atresia, the ease of right atria1 emptying depends on the size of the interatrial communication. Thus, in some patients with small atria1 defects, right atria1 systolic pressure is increased, resulting in presystolic “a” waves and hepatic pulsations, Similar presystolic “a” waves are seen in severe pulmonic stenosis and are produced by increased right ventricular end-diastolic pressure or decreased right ventricular compliance from severe hypertrophy. The same mechanisms produce presystolic jugular “a” waves in marked pulmonary hypertension. Tricuspid valve incompetence secondary to right ventricular dilatation from severe pulmonic stenosis or pulmonary hypertension results in systolic jugular pulsations. Systemic venous hypertension is rare in Fallot’s tetralogy SO that the combination of severe pulmonic stenosis, cyanosis and increased venous pressure generally indicates that the ventricular septum is intact. HEART SIZE
The size and configuration of the cardiac silhouette in patients with cyanotic congenital heart disease are affected by anemia ( Fig. 1) . Although encountered in any cardiac malformation with cyanosis, this problem is seen most frequently in infants and toddlers with severe Fallot’s tetralogy and iron deficiency anemia.
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Considerable cardiomegaly occurs in these patients and distorts the “classica .Y configuration and normal heart size usually associated with Fallot’s tetralog YThe heart size returns to normal after correction of the anemia. Since 2u-r elevated hemoglobin and hematocrit are the rule with right-to-left shunts, a significant iron deficiency anemia may be present with a “normal” hemoglobi n.
Fig. I.-Effect of iron deficiency anemia on heart size in Fsllot’s tetralogy. Hemoglobin 11 Gm. per cent. B. Hemoglobin 17 Cm. per cent.
A.
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SAMUEL KAPLAN
Thus, 11 Gm. per cent hemoglobin is within normal limits for a healthy toddler but may indicate severe iron deficiency anemia in Fallot’s tetralogy. The heart size and configuration may change dramatically because of cornplications of corrective surgery. Cardiomegaly and unusual cardiac shape are sometimes seen after surgery for Fallot’s tetralogy. Contributing factors include: ( 1) inadequate relief of right ventricular outflow obstruction; ( 2) persistence of the VSD with left-to-right shunt; (3) inadequate coronary blood flow during cardiotomy because of prolonged periods of occlusion of the ascending aorta; and (4) aneurysm of the right ventricular outflow at the site of ventriculotomy or prosthesis. Palliation for arterial transposition (Rashkind or Blalock-Hanlon operation with or without pulmonary arteri$ banding) resulti in decrease in heart size and pulmonary overcirculation. Recurrence of cardiomegaly and inpalliation. creased pulmonary blood flow generally indicate inadequate AUSCULTATION
An estimate of the severity of the obstruction of valvuh pulmonic stenosis u;!th intact ventricular septum can be made from the auscultatory findings (Fig. 2A ) . These depend on prolongation of right ventricular systole, limited mobility
Fig. B.-Idealized diagrams of auscultatory findings In right ventricular outflow obstruction.
VALVULAR PULMONIC STENOSIS
FALLOTk TSTRALOGY
Valvular pulmonic stenosis with
intact
ventricular septum. [ncreasing severity of obstruction is associated with proof right longation
I
!I
ventricular systole SO Moderate that the systolic murmur (SM) is louder in late systale. Clicks are audible in milder lesions. Pulmonary valve closure is softer and more delayed in severe obstruction. R R Cyanotic Fallot’s tetralogy. The systolic murmur is m -+ @,, T either short (A), ansystolic with mi Bsysa ‘s 0’ ‘s tolic accentuation (B), or ejection with late systolic accentuation (C). The second heart sound is usually single but sometimes a delayed pulmonary valve closure is audible. lzfirst heart sound, -ejection click, Azaortic valve closure, P=pulmonic valve closure, 4= atria1 or fourth heart sound. P, QRS and T refer to the electrocardiographic waves.
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HEMODYNAMIC
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of the deformed pulmonary valve and low pressure in a dilated pulmonary artery. The character of the ejection systolic murmur is contingent upon the degree of obstruction. When the lesion is mild, the murmur is loudest in midsystole, ends before the aortic component of the second sound and is frequently preceded by a pulmonic ejection sound. The duration of right ventricular systole is increased when obstruction is so severe that blood continues to be ejected in late systole. This produces an ejection systolic murmur which starts well after the first heart sound, is loudest at the end of systole, and encroaches on or ends after the aortic component of the second sound. The character of the second sound is also of value in determining the severity of the obstruction. The second heart sound is split and the interval between the aortic and the delayed pulmonic component increases as right ventricular pressure rises (Fig. 3). This time interval is of value in estimating right ventricular pressure. The intensity of the pulmonary component of the second sound is inversely proportionate to the severity of the lesion and may be absent when right ventricular hypertension is extreme. Frequently an atria1 sound is audible when right atria1 pressure is increased. The auscultatory findings in Fallot’s tetralogy are also dependent upon the abnormal hemodynamics (Fig. 2B). In an intensely cyanotic patient with a large right-to-left shunt and minimal or absent left-to-right shunt, the murmur is generated by blood flow through the right ventricular outflow obstruction. This results in an ejection systolic murmur of varying duration. The murmur may be preceded by an aortic ejection click from the large aorta which carries a considerable proportion of the blood ejected from the heart. Generally, the second heart sound is single and is produced by closure of the aortic valve. When pulmonary valve closure is audible, it is delayed and diminished. In a mildly or moderately cyanotic patient with a significant left-to-right shunt and 140
1
. . . .
Fig. 3.-Relationship betwben width of split of the second heart sound and right ventricular peak systolic pressure. The split
.
. l
l
l *e
.
.
. l
l .
l .
l
.
.
.
increases as right ventricular pressure rises,
20 40 60 80 100 120 140 0 Width of Split of Second Sound (m.sec)
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KAPLAN
a small right-to-left shunt, the above auscultatory findings are supplemented by a pansystolic murmur at the lower left sternal edge, produced by turbulence of blood across the ventricular defect. Severe pulmonary hypertension (e.g., Eisenmenger’s syndrome) also produces easily recognizable auscultatory findings. The first heart sound is usually followed by a pulmonic ejection click generated by the dilated, hypertensive pulmonary artery. An ejection systolic murmur of varying intensity and duration is usual. The second heart sound is booming in character because of the loud pulmonary valve closure. This sound is closely split or single in patients with VSD but can remain widely split if the pulmonary hypertension is due to an ASD. Functional incompetence of the pulmonary valve produces an early blowing diastolic murmur at the left sternal edge (Graham Steel1 murmur). THE ELECTROCARDIOGRAM The easiest and most accurate way to determine the presence of ventricular hypertrophy is with the electrocardiogram. A diagnosis of cyanotic tetralogy of Fallot is unlikely if EKG evidence of right ventricular hypertrophy is absent. Eisenmenger’s syndrome is also associated with EKG signs of marked right ventricular hypertrophy. In both of these conditions, right atria1 hypertrophy may be present as determined by prominent, spiked P waves. The EKG pattern is variable in arterial transposition. Generally the findings are right axis deviation and right ventricular hypertrophy with or without prominent P waves. In patients with a large pulmonary blood flow, the axis is either to the right or normal, but occasionally left axis deviation is present.3 These findings are associated with isolated right ventricular hypertrophy, biventricular hypertrophy or occasionally, isolated dominance of the left ventricle. Isolated right ventricular hypertrophy is usual when pulmonary vascular obstruction is present. In the newborn, the EKG may be normal or show right ventricular hypertrophy. Tricuspid valve disease as a part of cardiovascular malformations with cyanosis is frequently suggested by the EKG. The classical findings in tricuspid atresia with underdeveloped right ventricle are left axis deviation, left ventricular hypertrophy and abnormally tall, spiked P waves. These EKG patterns may also be seen in arterial transposition with tricuspid atresia, although these patients may show right axis deviation, and the signs of left ventricular hypertrophy may be inconspicuous. Pulmonary atresia with an intact ventricular septum is usually associated with a hypoplastic thick-walled right ventricle and a small tricuspid orifice. However, in 15 to 20 per cent the right ventricle is normal or large when the tricuspid valve is functionally incompetent. Intermediate forms between these two extremes are common. The EKG is very helpful in establishing a diagnosis in patients beyond the newborn period because there is good correlation between right ventricular size and the electrocardiogram. If the right ventricle is small, signs of left ventricular hypertrophy are usual, and the frontal QRS axis is either normal or to the right. This helps to exclude tricuspid atresia. In patients with a normal or large right ventricle, signs of right ventricular hypertrophy are common.
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AM) ~MODYNAMIC
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SUMMARY
Routine clinical, radiographic and electrocardiographic examinations in patients with cyanotic congenital heart disease usually lead to a presumptive diagnosis of the functional derangement. The clinical and electrocardiographic information that enhance the diagnostic accuracy of roentgenographic findings are detailed. Generally, definitive anatomic diagnosis requires selective angiocardiography. Physiologic consequences of the anomalies are determined by measurement of intravascular pressures and resistances, blood flow and direction of shunt. REFERENCES 1. Blalock, A., and Hanlon, C. R.: The surgical treatment of complete transposition of the aorta and pulmonary artery. Surg. Gynec. Obstet. 90:1, 1950. 2. Currarino, G., Edwards, F. K., and Kaplan, 8: Hypoplasia of the left heart complex: Report of two cases showing premature obliteration of the foramen ovale and differential cyanosis. Amer. J. Dis. Child. 979339, 1959. 3. Gasul, B. M., Arcilla, R. A., and Lev, M.: Heart Disease in Children. Philadelphia, J. B. Lippincott Company, 1966, pp. 531535. 4. Cuntheroth, W. G., Morgan, B. C., and Mullins, G. L.: Physiologic studies of
paroxysmal hyperpnea in cyanotic congenital heart disease. Circulation 31:70, 1965. 5. Keith, J. D., Rowe, R. D., and Vlad, P.: Heart Disease in Infancy and Childhood, ed. 2. New York, Macmillan Co., 1967, pp. 882887. 6. Plauth, W. H., Jr., Nadas, A. 8, Bernhard, W. F., and Gross, R. E.: Transposition of the great arteries: Clinical and physiological observations on 74 patients treated by palliative surgery. Circulation 37:316, 1968. 7. Rashkind, W. J., and Miller, W. W.: Creation of an atial septal defect without thoracotomy: A palliative approach to complete transposition of the great arteries. J.A.M.A. 196:991, 1966.
M.D.
I
N THE MAJORITY OF PATIENTS with cyanotic congenital heart disease, a presumptive diagnosis of the functional derangement can be made on the basis of clinical, electrocardiographic and roentgenographic features. However, the precise anatomic details and the physiologic consequences of specific anomalies generally require specialized studies, including selective angiocardiography as well as measurement of blood flow, direction of shunt, and intravascular pressures and resistance. The purpose of this paper is to suggest the clinical and electrocardiographic information that may be of value in the interpretation of roentgen findings. INC~ENCE
The incidence and type of cyanotic congenital heart disease vary in each age group, with the highest mortality occurring in the first year of life. In the neonatal period, transposition of the great vessels, hypoplastic left heart syndrome, and severe forms of Fallot’s tetralogy (with pulmonary arterial hypoplasia or atresia) comprise more than 75 per cent of all symptomatic patients. Prior to the widespread use of palliative therapy for transposition of the great vessels, the majority of these babies succumbed during the first 6 months of life. However, the success of, balloon septostomy’ or excision of the atria1 septum1 with or without pulmonary artery banding6 has increased the prevalence of arterial transposition in older infants and young children. In this age group most patients with cyanotic congenital heart disease now have either Fallot’s tetralogy or transposition of the great vessels. The more common types of cyanotic congenital, heart disease in adolescents and adults are the Eisenmenger’s physiology (bidirectional or right-to-left shunt across a VSD, ASD or PDA) and Fallot’s tetralogy, usually with a functioning surgical systemic-pulmonary artery anastomosis. Less frequent types of cyanotic congenital heart disease encountered in infancy include anomalies of pulmonary and systemic venous return, tricuspid atresia or stenosis with underdeveloped right ventricle, isolated pulmonic stenosis with right-to-left shunt across the atria1 septum, single ventricle with puhnonic stenosis or transposition,, endocardial cushion defect with pulmonic stenosis, double outlet right ventricle with pulmonic stenosis, and pulmonary atresia with intact ventricular septum. In this age group, cyanosis may be produced by pulmonary hypertension due to elevated pulmonary arteriolar From the Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio. Supported in part by USPHS Grants HE05728 and HE02427. SAMUEL KAPLAN, M.D.: Professor of Pediatrics and Associute Professor of Medicine, University of Cincinnati College of Medicine; Director, Division of Cardiology, Children’s Hospital, Cincinnati, Ohio. SEMINARSIN ROENTGENOLOGY, VOL. 3, No. 4 (OCTOBER), 1968
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KAPLAN
resistance or pulmonary venous hypertension. Ebstein’s anomaly, truncus arteriosus with decreased pulmonary blood flow and pulmonary arteriovenous fistula may be seen in any age group. CYANOSIS
Generally, at least 5 Gm. of reduced hemoglobin per 100 ml. of circulating blood must be present before cyanosis can be appreciated clinically. Therefore, if the cyanotic patient’s hemoglobin is 15 Gm. per cent, one third or more is in the form of reduced hemoglobin. The normal arterial oxygen saturation is about 95 per cent and mixed systemic venous blood at rest is about 70 to 75 per cent saturated. It is known that 1 ml. of oxygen is taken up by 0.75 Cm. hemoglobin or 1 Gm. of hemoglobin takes up 1.33 ml. of oxygen. Thus, in an individual with 15 Gm. per cent of hemoglobin the oxygen capacity is about 20 volumes per cent ( 15 x 1.33). Generally the more intense the cyanosis the more severe the polycythemia and digital clubbing. The volume of venoarterial or right-to-left shunt (central cyanosis) is the most important factor in determining the amount of reduced hemoglobin in arterial blood. Cyanosis is evident because arterial unsaturation results in a low capillary oxygen saturation and a further decrease in the oxygen content of venous blood. The greater the volume of right-to-left shunt, the more intense is the cyanosis. The volume of pulmonary blood flow and the adequacy of intracardiac mixing are also important factors in determining the degree of cyanosis. Severe pulmonic stenosis decreases pulmonary blood flow and the amount of hemoglobin available for oxygenation. This is particularly true in Fallot’s tetralogy in which the right-to-left shunt across the VSD is increased during exercise because of the relatively fixed right ventricular outflow obstruction and pulmonary blood flow. However, isolated pulmonic stenosis with intact ventricular and atria1 septum is not associated with cyanosis unless heart failure supervenes. Inadequacy of intracardiac mixing is seen especially in arterial transposition with intact ventricular septum. In spite of increased pulmonary blood flow in these patients, cyanosis is intense because a sufhcient amount of oxygenated blood is unable to reach the systemic circulation, However, when adequate intracardiac mixing of pulmonic and systemic venous blood occurs in the presence of a torrential pulmonary flow, cyanosis is absent or minimal. Examples of these circumstances include truncus arteriosus with large pulmonary arteries and excessive pulmonary flow, total anomalous pulmonary venous return without pulmonary venous obstruction, and Taussig-Bing anomaly in infants. In these patients, arterial unsaturation is mild and mixed venous blood is highly saturated so that the arteriovenous oxygen difference is small. Peripheral cyanosis is seen in patients whose tissue oxygen utilization is increased. Although the arterial saturation is normal, excessive extraction of oxygen by the tissues results in a large arteriovenous oxygen difference. This is seen in some patients with congestive heart failure and decreased cardiac output. Differential cyanosis is of great value in diagnosis and depends on perfusion of the lower thoracic and abdominal aorta with blood from the pulmonary
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artery via a PDA. The line of demarcation is at the level of the brim of the pelvis since the chest and abdominal wall are supplied by branches of the subclavian artery (internal mammary and superficial epigastric) which arise above the entry of the ductus into the aorta. In severe pulmonary hypertension associated with PDA, with or without aortic coarctation or interruption of the aortic isthmus, the lower extremities are blue since they are perfused with unsaturated blood from the pulmonary artery. In some patients, with pulmonary hypertension and PDA but without coarctation, pulmonary arterial blood may also enter the left subclavian artery, causing cyanosis of the left arm as well. Transposition of the great vessels and PDA, with or without aortic coarctation, may be associated with perfusion of the lower thoracic aorta with arterialized blood via the pulmonary artery, so that the lower extremities are pinker than the upper portion of the body. Some patients with hypoplastic left heart syndrome and a minute opening in the aortic valve have an unusual distribution of cyanosis.? Since left ventricular ejection is preferential to the innominate artery, the right upper quadrant of the body is relatively pink and the rest of the body is cyanotic. CLINICAL
Hypercyanotic
SIGNS
Attacks (Anoxic or Blue Spells)
Unpredictable attacks of paroxysmal dyspnea are a serious problem in infants and are of grave prognostic significance. They are seen most frequently with severe tetralogy of Fallot but are not pathognomonic of this disease. These spells have also been occasionally described in infants with pulmonary stenosis and intact ventricular septum, tricuspid atresia and underdeveloped right ventricle, and arterial transposition with intact ventricular septum. The disappearance or attenuation of the systolic murmur and the reduction of arterial oxygen saturation and pulmonary artery pressure during an episode suggest that the anoxic spells in Fallot’s tetralogy are associated with right ventricular outflow spasm. Guntheroth et al.’ suggested that hyperpnea precipitates the attacks. Systemic venous return is increased during hyperpnea. When the pulmonary blood flow is fixed or decreased, the right-to-left shunt is increased. The resultant arterial hypoxia, metabolic acidosis and increased carbon dioxide tension further stimulate respiration and the hyperpnea continues. Cerebral
Thrombosis
This occurs especially in the first 2 years of life. Since the viscosity of blood is increased by polycythemia, this complication is more frequent in malformations associated with severe cyanosis. Thus, cerebrovascular accidents are more often seen in patients with Fallot’s tetralogy, arterial transposition and tricuspid atresia. Brain Abscess
Although less than 1 per cent of patients with congenital heart disease suffer from this complication, about 10 per cent of patients with brain abscess have underlying congenital heart disease.” Since brain abscess rarely occurs before the age of 2, infants with cyanotic congenital heart disease and neurologic signs
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are usually suffering from cerebral thrombosis. Cerebral abscess is seen almost exclusively in patients with cyanotic congenital heart disease and right-to-left shunt, although there are isolated reports of its occurrence in the usual forms of ASD and VSD. Cerebral abscess has been recorded in patients with Fallot’s tetralogy, arterial transposition, Eisenmenger’s complex, tricuspid atresia, truncus arteriosus, Ebstein’s anomaly and single ventricle. Distant sites of infection are demonstrated in 40 per cent” so that the abscess is presumably seeded either by an infected “paradoxical” embolus or bacteremia. Bacterial
Endocarditis
At Children’s Hospital, the commonest underlying cardiovascular lesion which is complicated by bacterial endocarditis is Fallot’s tetralogy with a functioning systemic-pulmonary artery anastomosis. Bacterial endocarditis has been encountered on 11 occasions in 9 patients out of a group of 30 with Fallot’s tetralogy and Potts anastomosis. Since bacterial endocarditis occurs less frequently after a Blalock-Taussig operation, it is probable that the near normal arterial oxygen saturation produced by the larger pulmonary blood flow which occurs after the Potts operation plays an important role in the development of the bacterial endocarditis. VENOUS PULSE AND PRESSURE
Inspection of the venous pressure is accomplished by observing the pulsation of the internal jugular vein with the patient lying comfortably with his head and shoulders propped to an angle of about 45 degrees. Since valves are absent in the superior vena caval system, venous pulsations are produced by pressure fluctuations in the right atrium. These changes occur with tricuspid or pulmonic valve disease, decreased right ventricular compliance, increased right ventricular end-diastolic pressure and severe pulmonary hypertension. In patients with tricuspid atresia, the ease of right atria1 emptying depends on the size of the interatrial communication. Thus, in some patients with small atria1 defects, right atria1 systolic pressure is increased, resulting in presystolic “a” waves and hepatic pulsations, Similar presystolic “a” waves are seen in severe pulmonic stenosis and are produced by increased right ventricular end-diastolic pressure or decreased right ventricular compliance from severe hypertrophy. The same mechanisms produce presystolic jugular “a” waves in marked pulmonary hypertension. Tricuspid valve incompetence secondary to right ventricular dilatation from severe pulmonic stenosis or pulmonary hypertension results in systolic jugular pulsations. Systemic venous hypertension is rare in Fallot’s tetralogy SO that the combination of severe pulmonic stenosis, cyanosis and increased venous pressure generally indicates that the ventricular septum is intact. HEART SIZE
The size and configuration of the cardiac silhouette in patients with cyanotic congenital heart disease are affected by anemia ( Fig. 1) . Although encountered in any cardiac malformation with cyanosis, this problem is seen most frequently in infants and toddlers with severe Fallot’s tetralogy and iron deficiency anemia.
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Considerable cardiomegaly occurs in these patients and distorts the “classica .Y configuration and normal heart size usually associated with Fallot’s tetralog YThe heart size returns to normal after correction of the anemia. Since 2u-r elevated hemoglobin and hematocrit are the rule with right-to-left shunts, a significant iron deficiency anemia may be present with a “normal” hemoglobi n.
Fig. I.-Effect of iron deficiency anemia on heart size in Fsllot’s tetralogy. Hemoglobin 11 Gm. per cent. B. Hemoglobin 17 Cm. per cent.
A.
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SAMUEL KAPLAN
Thus, 11 Gm. per cent hemoglobin is within normal limits for a healthy toddler but may indicate severe iron deficiency anemia in Fallot’s tetralogy. The heart size and configuration may change dramatically because of cornplications of corrective surgery. Cardiomegaly and unusual cardiac shape are sometimes seen after surgery for Fallot’s tetralogy. Contributing factors include: ( 1) inadequate relief of right ventricular outflow obstruction; ( 2) persistence of the VSD with left-to-right shunt; (3) inadequate coronary blood flow during cardiotomy because of prolonged periods of occlusion of the ascending aorta; and (4) aneurysm of the right ventricular outflow at the site of ventriculotomy or prosthesis. Palliation for arterial transposition (Rashkind or Blalock-Hanlon operation with or without pulmonary arteri$ banding) resulti in decrease in heart size and pulmonary overcirculation. Recurrence of cardiomegaly and inpalliation. creased pulmonary blood flow generally indicate inadequate AUSCULTATION
An estimate of the severity of the obstruction of valvuh pulmonic stenosis u;!th intact ventricular septum can be made from the auscultatory findings (Fig. 2A ) . These depend on prolongation of right ventricular systole, limited mobility
Fig. B.-Idealized diagrams of auscultatory findings In right ventricular outflow obstruction.
VALVULAR PULMONIC STENOSIS
FALLOTk TSTRALOGY
Valvular pulmonic stenosis with
intact
ventricular septum. [ncreasing severity of obstruction is associated with proof right longation
I
!I
ventricular systole SO Moderate that the systolic murmur (SM) is louder in late systale. Clicks are audible in milder lesions. Pulmonary valve closure is softer and more delayed in severe obstruction. R R Cyanotic Fallot’s tetralogy. The systolic murmur is m -+ @,, T either short (A), ansystolic with mi Bsysa ‘s 0’ ‘s tolic accentuation (B), or ejection with late systolic accentuation (C). The second heart sound is usually single but sometimes a delayed pulmonary valve closure is audible. lzfirst heart sound, -ejection click, Azaortic valve closure, P=pulmonic valve closure, 4= atria1 or fourth heart sound. P, QRS and T refer to the electrocardiographic waves.
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of the deformed pulmonary valve and low pressure in a dilated pulmonary artery. The character of the ejection systolic murmur is contingent upon the degree of obstruction. When the lesion is mild, the murmur is loudest in midsystole, ends before the aortic component of the second sound and is frequently preceded by a pulmonic ejection sound. The duration of right ventricular systole is increased when obstruction is so severe that blood continues to be ejected in late systole. This produces an ejection systolic murmur which starts well after the first heart sound, is loudest at the end of systole, and encroaches on or ends after the aortic component of the second sound. The character of the second sound is also of value in determining the severity of the obstruction. The second heart sound is split and the interval between the aortic and the delayed pulmonic component increases as right ventricular pressure rises (Fig. 3). This time interval is of value in estimating right ventricular pressure. The intensity of the pulmonary component of the second sound is inversely proportionate to the severity of the lesion and may be absent when right ventricular hypertension is extreme. Frequently an atria1 sound is audible when right atria1 pressure is increased. The auscultatory findings in Fallot’s tetralogy are also dependent upon the abnormal hemodynamics (Fig. 2B). In an intensely cyanotic patient with a large right-to-left shunt and minimal or absent left-to-right shunt, the murmur is generated by blood flow through the right ventricular outflow obstruction. This results in an ejection systolic murmur of varying duration. The murmur may be preceded by an aortic ejection click from the large aorta which carries a considerable proportion of the blood ejected from the heart. Generally, the second heart sound is single and is produced by closure of the aortic valve. When pulmonary valve closure is audible, it is delayed and diminished. In a mildly or moderately cyanotic patient with a significant left-to-right shunt and 140
1
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Fig. 3.-Relationship betwben width of split of the second heart sound and right ventricular peak systolic pressure. The split
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l .
l
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increases as right ventricular pressure rises,
20 40 60 80 100 120 140 0 Width of Split of Second Sound (m.sec)
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a small right-to-left shunt, the above auscultatory findings are supplemented by a pansystolic murmur at the lower left sternal edge, produced by turbulence of blood across the ventricular defect. Severe pulmonary hypertension (e.g., Eisenmenger’s syndrome) also produces easily recognizable auscultatory findings. The first heart sound is usually followed by a pulmonic ejection click generated by the dilated, hypertensive pulmonary artery. An ejection systolic murmur of varying intensity and duration is usual. The second heart sound is booming in character because of the loud pulmonary valve closure. This sound is closely split or single in patients with VSD but can remain widely split if the pulmonary hypertension is due to an ASD. Functional incompetence of the pulmonary valve produces an early blowing diastolic murmur at the left sternal edge (Graham Steel1 murmur). THE ELECTROCARDIOGRAM The easiest and most accurate way to determine the presence of ventricular hypertrophy is with the electrocardiogram. A diagnosis of cyanotic tetralogy of Fallot is unlikely if EKG evidence of right ventricular hypertrophy is absent. Eisenmenger’s syndrome is also associated with EKG signs of marked right ventricular hypertrophy. In both of these conditions, right atria1 hypertrophy may be present as determined by prominent, spiked P waves. The EKG pattern is variable in arterial transposition. Generally the findings are right axis deviation and right ventricular hypertrophy with or without prominent P waves. In patients with a large pulmonary blood flow, the axis is either to the right or normal, but occasionally left axis deviation is present.3 These findings are associated with isolated right ventricular hypertrophy, biventricular hypertrophy or occasionally, isolated dominance of the left ventricle. Isolated right ventricular hypertrophy is usual when pulmonary vascular obstruction is present. In the newborn, the EKG may be normal or show right ventricular hypertrophy. Tricuspid valve disease as a part of cardiovascular malformations with cyanosis is frequently suggested by the EKG. The classical findings in tricuspid atresia with underdeveloped right ventricle are left axis deviation, left ventricular hypertrophy and abnormally tall, spiked P waves. These EKG patterns may also be seen in arterial transposition with tricuspid atresia, although these patients may show right axis deviation, and the signs of left ventricular hypertrophy may be inconspicuous. Pulmonary atresia with an intact ventricular septum is usually associated with a hypoplastic thick-walled right ventricle and a small tricuspid orifice. However, in 15 to 20 per cent the right ventricle is normal or large when the tricuspid valve is functionally incompetent. Intermediate forms between these two extremes are common. The EKG is very helpful in establishing a diagnosis in patients beyond the newborn period because there is good correlation between right ventricular size and the electrocardiogram. If the right ventricle is small, signs of left ventricular hypertrophy are usual, and the frontal QRS axis is either normal or to the right. This helps to exclude tricuspid atresia. In patients with a normal or large right ventricle, signs of right ventricular hypertrophy are common.
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SUMMARY
Routine clinical, radiographic and electrocardiographic examinations in patients with cyanotic congenital heart disease usually lead to a presumptive diagnosis of the functional derangement. The clinical and electrocardiographic information that enhance the diagnostic accuracy of roentgenographic findings are detailed. Generally, definitive anatomic diagnosis requires selective angiocardiography. Physiologic consequences of the anomalies are determined by measurement of intravascular pressures and resistances, blood flow and direction of shunt. REFERENCES 1. Blalock, A., and Hanlon, C. R.: The surgical treatment of complete transposition of the aorta and pulmonary artery. Surg. Gynec. Obstet. 90:1, 1950. 2. Currarino, G., Edwards, F. K., and Kaplan, 8: Hypoplasia of the left heart complex: Report of two cases showing premature obliteration of the foramen ovale and differential cyanosis. Amer. J. Dis. Child. 979339, 1959. 3. Gasul, B. M., Arcilla, R. A., and Lev, M.: Heart Disease in Children. Philadelphia, J. B. Lippincott Company, 1966, pp. 531535. 4. Cuntheroth, W. G., Morgan, B. C., and Mullins, G. L.: Physiologic studies of
paroxysmal hyperpnea in cyanotic congenital heart disease. Circulation 31:70, 1965. 5. Keith, J. D., Rowe, R. D., and Vlad, P.: Heart Disease in Infancy and Childhood, ed. 2. New York, Macmillan Co., 1967, pp. 882887. 6. Plauth, W. H., Jr., Nadas, A. 8, Bernhard, W. F., and Gross, R. E.: Transposition of the great arteries: Clinical and physiological observations on 74 patients treated by palliative surgery. Circulation 37:316, 1968. 7. Rashkind, W. J., and Miller, W. W.: Creation of an atial septal defect without thoracotomy: A palliative approach to complete transposition of the great arteries. J.A.M.A. 196:991, 1966.