Cong.heart_desiases.docx. Олена Костянтинівна Редько

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1 Cong.heart_desiases.docx Олена Костянтинівна Редько 2015

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3 Ключові терміни: 3 Зміст Ключові терміни: Acyanotic Congenital Heart Disease Heart and Main Vessels Atrioventricular Septal Defects (Ostium Primum and Atrioventricular Canal or Endocardial Cushion Defects) Cyanotic Congenital Heart Disease

4 Ключові терміни: 4 Acyanotic Congenital Heart Disease Heart and Main Vessels Atrioventricular Septal Defects (Ostium Primum and Atrioventricular Canal or Endocardial Cushion Defects) Cyanotic Congenital Heart Disease Ключові терміни: Atrial Septal Defect, Atrioventricular Septal Defects (Ostium Primum and Atrioventricular Canal or Endocardial Cushion Defects), Coarctation of the aorta, Ebstein anomaly, Hypoplastic left heart syndrome, PATHOPHYSIOLOGY, Questions, Teaching Points:, Tetralogy of Fallot, The EKG, The chest radiograph, The clinical features, Total anomalous pulmonary venous return (TAPVR), Transposition of the great vessels, Treatment, Tricuspid atresia, Truncus arteriosus, Ventricular septal defects (VSD), atrial septal defects (ASD), and patent ductus arteriosus (PDA), patent ductus arteriosus (PDA) Acyanotic Congenital Heart Disease Heart and Main Vessels A 4 year old male presents in the office for a preschool physical examination. In the course of the interview, his mother mentions that he seems to get short of breath with exercise recently. It is especially noticeable during his swimming lessons when he tires before the other children do in his class. He has otherwise been in good health since his last physical exam in the previous year. His records for the past year show 3 office visits for minor upper respiratory illnesses, and no emergency room visits. He has never had wheezing during his colds. Exam: T37.5, P92, R25, BP right arm 97/70, oxygen saturation 98% in room air. Height and weight are

5 Ключові терміни: 5 Exam: T37.5, P92, R25, BP right arm 97/70, oxygen saturation 98% in room air. Height and weight are at the 25th percentile. He is cooperative and well nourished in no distress. HEENT and neck exams are normal. His chest is symmetrical. Heart: No palpable thrill, normal 1st and 2nd heart sounds; no clicks or rubs; grade 1/6 ejection systolic murmur heard along the left sternal border with radiation to the back between the scapulae; no diastolic murmur. Lungs are clear to auscultation. Abdomen without no organomegaly or masses palpable. Genitalia: normal male. Extremities: Femoral pulses are slightly diminished to palpation; no peripheral edema, clubbing or cyanosis of the nail beds. His neurological is normal. He receives his immunizations, and tuberculin skin test, and because of the new onset heart murmur, a chest x-ray and EKG are ordered. He returns in 3 days to have his skin test read and to review his cardiac tests. Before entering the exam room the nurse remeasures his vital signs and records in his chart: BP left arm 127/86, P88, R24. His chest x-ray shows a cardiac/thoracic ratio of 0.55, normal cardiac configuration, and normal pulmonary vasculature. His EKG has tall R waves of 40 mm in lead V5, and 35 mm in lead V6. An echocardiogram is performed the following day and demonstrates a coarctation of the aorta, and bicuspid aortic valve. A MRI shows a discrete narrowing of the distal aortic arch just beyond the origin of the left subclavian artery and also reveals an aberrant right subclavian artery originating from the proximal descending aorta below the coarctation. Coarctation of the aorta Coarctation of the aorta is classified as an acyanotic congenital heart defect and belongs to that group of cardiac anomalies that is the result of abnormal fetal cardiac formation, that does NOT cause shunting of blood from the venous to the systemic side of the heart (i.e., it does NOT cause right to left shunting), and that may be manifested and clinically detectable some time after birth. With the advent of fetal echocardiography, these lesions are sometimes detected before birth. A list of the acyanotic lesions can be made by enumerating the structures encountered by the flow of blood through the different parts of the heart beginning with the venous side. The most common anomalies would thus include: tricuspid valve stenosis/regurgitation, Ebstein's anomaly of the tricuspid valve (can be cyanotic in infants), pulmonic valve stenosis/regurgitation, subvalvular and supravalvular pulmonic stenosis, partial anomalous pulmonary venous drainage to the right side of the heart, atrial septal defect (secundum, primum, sinus venosus), mitral valve stenosis/regurgitation, ventricular septal defect, aortic valve stenosis/regurgitation, subvalvular and supravalvular aortic stenosis, patent ductus arteriosus, and coarctation of the aorta. Acyanotic congenital lesions account for 70% of all congenital heart disease, the most common of which, as isolated lesions, are ventricular septal defects (most common), patent ductus arteriosus, atrial septal defect and pulmonic stenosis. Coarctation of the aorta accounts for (6%) of all congenital heart disease. Patients with Turner syndrome have coarctation more commonly than the general population. Coarctation of the aorta results from constriction of the tissue of the distal aortic arch at the junction with the descending aorta and near the insertion of the ductus arteriosus. Various theories have been proposed to explain this maldevelopment. One popular theory associates the presence of ductal tissue encircling the aorta at the site of the coarctation suggesting a constrictive effect of the ductile tissue. Although present at birth, coarctation of the aorta may not cause symptoms until early childhood and sometimes not until late childhood, depending on the severity of the coarctation, and the presence of associated cardiac lesions. If a ventricular septal defect is also present and is large, the coarctation of the aorta will cause increased left to right shunting across the defect, producing congestive heart failure within the first few months of life as the pulmonary resistance decreases after birth. A patent ductus arteriosus located proximal to the coarctation would likewise increase pulmonary shunting through the ductus resulting in congestive heart failure. If the ductus is located distal to the coarctation, signs and symptoms may be delayed. Other anomalies associated with aortic coarctation include a bicuspid aortic valve (85%) that may obstruct left ventricular output, and an aberrant origin of the right subclavian artery distal to the coarctation (1%). The latter will cause the blood pressure of the right arm to be equal to the leg, and may mislead one from the correct diagnosis. It is important to measure the blood pressure in both arms and at least one leg in order to detect the blood pressure differential caused by an aortic coarctation. If coarctation of the aorta is an isolated lesion, the typical symptoms may include: shortness of breath with exertion, leg pain with exercise, and rarely, chest pain with exercise. Physical findings include: upper extremity hypertension with a blood pressure differential between arm and leg (obtain BP in both arms and one leg), a systolic murmur heard along the left sternal border and especially well over the back between the scapulae, and diminished and delayed pulses in the lower extremities when compared with the upper extremities. A chest x-ray may display cardiomegaly with a left ventricular hypertrophy configuration. In long standing cases, rib notching due to erosion of the lower anterior portion of the rib by dilated collateral arteries can be appreciated. The echocardiogram demonstrates narrowing of the

6 Ключові терміни: 6 distal aortic arch with increased velocities on pulsed and color Doppler. The pulsed Doppler waveform has a typical prolonged systolic phase extending throughout systole. The MRI produces a static but clearer picture, than the echocardiogram, of the anatomy of the coarctation. An angiogram is sometimes necessary to clarify associated cardiac lesions. There are several surgical techniques used to repair a coarctation of the aorta. Each technique has had its own proponents at one time or another. If the coarcted segment is short and discrete, resection and end to end anastomosis of the proximal and distal ends is possible. If the coarctation is a long tubular obstruction, resection with interposition of a tube graft would be necessary. Some surgeons favor a longitudinal incision with insertion of a synthetic graft to enlarge the diameter. In the young infant, sacrificing the left subclavian artery, and using the transected blood vessel as a graft by turning it down and sewing it into the aortic wall was popular at one time. Catheter balloon dilatation of native coarctations has not been as successful as dilatation of postoperative restenosis of a coarctation. The former technique has resulted in late appearance of aneurysms. The use of stents to reinforce the arterial wall is now preferred to balloon dilation alone. Balloon Angioplasty A postoperative complication that is now rare is the syndrome of mesenteric arteritis, caused by reflex spasm of mesenteric arteries that are suddenly exposed to higher pressures after the coarctation is removed. The spasm can be severe enough to result in bowel ischemia. Patients are being operated on at a younger age now so that the mesenteric arteries do not have as long a period of exposure to low pressures and are therefore less reactive.

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10 Ключові терміни: 10 Ventricular septal defects (VSD), atrial septal defects (ASD), and patent ductus arteriosus (PDA) account for a large percentage of all congenital heart defects. They share common physiologic hemodynamics and will be discussed together. Ventricular septal defects (VSD)

11 Ключові терміни: 11 These defects represent abnormal communications between the high pressure left side of the heart and the low pressure right side of the heart. The pressure differential results in a left-to-right shunting of blood through the defect. The consequences of this shunting of blood are: turbulence of abnormal blood flow producing a heart murmur in systole and sometimes in diastole; excessive blood flow into the lungs causing shortness of breath and increased pulmonary vascularity on a chest x-ray; and increased volume overload of the myocardium resulting in hypertrophy of myocardium and chamber dilatation. The murmur of a VSD is located at the lower left sternal border and is dictated by the anatomic location of the defect in relation to the chest wall. Since flow across the VSD occurs as long as there is a pressure differential between left and right ventricles, the timing of the murmur in this lesion is pansystolic. The high pressure turbulence of the shunted blood produces a harsh quality to the murmur. When the pulmonic flow exceeds the systemic flow by a ratio of 2:1, an apical diastolic murmur is produced due to excessive flow during recirculation across the mitral valve. Frequently, a VSD murmur is not heard at birth (day 1 of life) since pulmonary vascular resistance and pulmonary pressure may still be high, limiting left to right shunting through the VSD. As pulmonary vascular resistance drops further, more left to right shunting through the VSD occurs, making the murmur audible on day 2 or day 3 of life. The murmur of an ASD is produced by excessive flow across the pulmonic and tricuspid valves resulting in a systolic murmur at the second left intercostal space and a mid-diastolic murmur over the lower right sternal area. Note that this is a flow murmur and NOT a murmur due to turbulent flow across the ASD. Flow across the ASD is low velocity and not turbulent and therefore produces no audible murmur itself. The flow through a PDA is continuous due to the existence of a constant pressure differential between aorta and pulmonary artery in both systole and diastole. The machinery quality of the murmur results from the rhythmic variation of the pressure differentiation during the cardiac cycle. The location of the murmur is at the upper left sternal border. A small shunt produces only a murmur but no symptoms. With increasing defect size and pulmonary flow, signs and symptoms of congestive heart failure occur: shortness of breath with exertion and in severe cases, also at rest; cough and susceptibility to pulmonary infections; hepatomegaly, splenomegaly, and lower extremity edema result from retrograde extension of the systemic venous congestion into the liver, spleen and legs.

12 Ключові терміни: 12 The chest x-ray in a left-to-right shunt lesion will demonstrate congested pulmonary vessels. Enlargement of specific cardiac chambers is due to excessive volume overload. The left atrium and ventricle are dilated in VSD and PDA, and the right heart chamber is dilated in ASD. The EKG reveals hypertrophy of the corresponding cardiac chambers. patent ductus arteriosus (PDA) Untreated defects with large shunts will eventually result in injury to the pulmonary arterioles, vascular obstruction, and pulmonary hypertension. The development of permanent injury to the pulmonary vessels is a function of the duration of the exposure to excessive blood flow and the anatomy, occurring more rapidly in VSD and PDA than in ASD. If this process is not reversed, Eisenmenger's complex of right to left shunting may occur as the right sided pressures (pulmonary hypertension) exceeds left sided pressures. Intracardiac repair of a VSD and ASD require cardiopulmonary bypass. Repair of a PDA is extracardiac and is achieved without cardiopulmonary bypass. The intracardiac defects can be closed by primary suturing of the edges of the defect if small, or by covering with a patch material if large. The PDA is usually tied off and divided. Complete heart block secondary to injury to the conduction system during repair of a VSD may require a pacemaker in the postoperative period. The knowledge of the location of the conduction system in relationship to the defect now makes this a rare complication. The mortality rate in experienced hands should be less than 5% if all ages are considered, with infants carrying a higher mortality rate especially if pulmonary hypertension is present. Questions True/False: Congenital heart disease is always detectable at birth True/False: Equal blood pressures in the right arm and left leg rule out the diagnosis of coarctation of the aorta Which are the three most common acyanotic congenital heart lesions? True/False: The presence of palpable femoral pulses rules out the diagnosis of aortic coarctation True/False: Surgical repair of PDA does not require cardiopulmonary bypass Explain how a child with an isolated VSD (classified as an acyanotic lesion) could become cyanotic?

13 Ключові терміни: True/False: Medical students and residents will typically not hear the murmur of a VSD during the initial newborn assessment in the nursery because the murmur of a VSD is subtle and low pitched. Answers to questions False. The physiologic pulmonary hypertension present in a newborn can prevent blood flow across a septal defect or PDA. These can be detected several hours after birth or several days after birth. Other congenital heart disease lesions may remain occult for longer period of time False. An aberrant right subclavian artery originating below a coarctation will produce equal pressures in the right arm and leg VSD, ASD, PDA. Of these, VSD is the most common False. Development of collateral vessels to the lower body can produce palpable femoral pulses True Congestive heart failure and pulmonary edema may cause hypoxia. If the hypoxia is severe enough, visible cyanosis will result, although this can be overcome with oxygen and other treatments for pulmonary edema and congestive heart failure. Long standing excessive pulmonary blood flow leads to pulmonary hypertension and Eisenmenger's complex, right to left shunting and cyanosis False. They cannot hear the murmur of a VSD on day 1 because on day 1, pulmonary vascular resistance is still high, which restricts left to right flow through the VSD. On day 2, pulmonary vascular resistance is lower, so left to right shunting through the VSD increases making the murmur louder. This is a 7 week old term female infant who presented with wheezing, coughing, and two episodes of nonbilious emesis. She was seen by her pediatrician, who suspected that she had bronchiolitis, and she was treated with oral albuterol syrup. An RSV (Respiratory Syncytial Virus) nasal prep was done, and this was negative; however, the patient's condition worsened, and she was brought to the Emergency Department later that evening. Exam: VS T37.2R, P168, R70, BP126/86, oxygen saturation 96% on room air. The infant was fussy, though consolable, with moderate respiratory distress. She was non-toxic in appearance. The anterior fontanelle was soft and flat. The pupils were equal and reactive and the mucus membranes were moist. The neck was supple. The lungs had diffuse wheezes and crackles bilaterally with intercostal retractions. Heart sounds were difficult to auscultate due to the noisy breathing, but no obvious loud pathologic murmur was heard. The abdomen was soft and nontender with active bowel sounds. The liver edge was palpated 3-4 cm below the right costal margin. Capillary refill time in the extremities was 3 seconds. The patient was placed on supplemental oxygen and a CXR was obtained. View CXR image. The CXR showed cardiomegaly and possibly increased pulmonary vascular markings consistent with congestive heart failure (CHF). The femoral pulses were difficult to palpate. Measurement of blood pressures in the four extremities showed 126/86 (left arm), 132/92 (right arm), 69/41 (left leg), and 63/59 (right leg). An EKG was done. View EKG.

14 Ключові терміни: 14 It is not easy to see the tracing of some of the precordial leads ecause they are very large. R2 (R wave of V2) extends into the tracing of V1. R4 is off the scale. Suffice it to say that all the R and S waves in V1-V6 are large. The axis of QRS is 90 degrees (roughly isoelectric in I and positive in AVF). This is a rightward axis. The large QRS's in V1-V6 meet voltage criteria for both LVH and RVH. This EKG shows biventricular hypertrophy. The patient was treated with furosemide, 1 mg/kg IV, and dobutamine, 5 mcg/kg/min as a continuous infusion, with marked improvement in respiratory status. The infant was admitted to the Pediatric Intensive Care Unit, and a cardiology consultation was obtained. An echocardiogram showed severe coarctation of the aorta, with a tight posterior shelf distal to the left subclavian artery. The left ventricle was dilated with markedly decreased function. The patient subsequently underwent operative repair of the coarctation, with an uneventful postoperative course. Teaching Points: 1. Wheezing and respiratory distress are a common presentation of CHF in infants. Tachypnea alone may be the earliest sign. Even in the midst of the busy winter bronchiolitis season, the clinician must be careful to consider that the infant with wheezing and tachypnea may be a presentation of CHF, rather than bronchiolitis. Physical exam findings of hepatomegaly or a gallop rhythm may aid in making the proper diagnosis. Parents may also give a history of poor feeding, slow weight gain, and increased sweating. A CXR showing cardiomegaly and increased pulmonary vascular markings will help to confirm the diagnosis. 2. Coarctation of the aorta may present at an early age, as in this case, with progressive CHF. More than 80% of infants with preductal COA develop CHF by 3 months of age. Coarctation of the aorta may also present in the first one or two weeks of life with a sudden state of shock with CHF and cardiovascular collapse when the ductus arteriosus closes (duct-dependent lesion). This is also the typical presentation of the hypoplastic left heart syndrome. Other types of congenital heart disease which may present early in infancy with CHF include large ventricular septal defects, a large patent ductus arteriosus, anomalous left coronary artery, and critical aortic or pulmonary stenosis. Acquired causes of CHF in young infants include viral myocarditis and supraventricular tachycardia. 3. COA can range in severity from very slight with minimal physiologic consequence to severe aortic coarctation or hypoplasia. More severe COA tends to present in infancy while less severe COA may present in later childhood or adolescence. The CXR of the young infant presenting with severe COA typically demonstrates cardiomegaly and increased pulmonary vascular markings (CHF). This is in contrast to the CXR of COA presenting later in childhood, which typically shows a normal or only slightly enlarged heart, and normal pulmonary vascular markings. Rib notching, although pathognomonic for COA, is rarely seen in children younger than 9 years of age. The aorta may develop dilation pre and post coarctation resembling a "3" (3 sign) when viewing the right side of the aorta on an overpenetrated film. If a barium swallow is performed the pre and post coarctation dilation of the aorta impinges upon the esophagus to it giving an "E" appearance to this area of the esophagus (E sign). These signs are not generally seen on routine views that would be ordered in the E.D. 4. Treatment of CHF in infancy requires attention to the cardinal ABCs of emergency medicine (Airway, Breathing, Circulation). Administration of supplemental oxygen should be considered as a firstline therapy. If the patient is unstable, intubation with positive-pressure ventilation may be required. To improve

15 Ключові терміни: 15 the patient is unstable, intubation with positive-pressure ventilation may be required. To improve cardiac contractility, inotropes such as digoxin or dobutamine may be needed. Dobutamine also has the advantage of decreasing afterload. Diuretics such as furosemide aid by decreasing preload. In severe cases, other vasoactive or inotropic agents such as sodium nitroprusside and amrinone may be considered. These agents should be used in the intensive care unit, using invasive hemodynamic monitoring. If a duct-dependent lesion is suspected, prostaglandin E1 should be started as a continuous infusion at 0.1 mcg/kg/min. This is 2-month old male who presents to the emergency department with a five day history of funny breathing. He was well until 5 days prior when his mother noted noisy, rapid breathing and a tactile temperature. Four days prior, he was taken to his private physician and was started on amoxicillin for otitis media. His lung exam at that time was normal. Two days prior he was taken to the emergency department and was noted to be wheezing. He was given an albuterol aerosol and was discharged on oral albuterol. He continued to have breathing problems at home and now returns to the emergency department since his condition has not improved. His birth history is unremarkable, and he has shown adequate weight gain since birth. There are no reported feeding problems according to his mother. His family history is significant for two siblings with asthma. Exam: T36.9, P168, BP 98/60. His respiratory rate varies between 60 and 80 per minute. His oxygen saturation is 97% in room air. His oxygen saturation improves to 100% on oxygen by nasal cannula at 2 liters per minute. He is a fussy infant with modest achypnea. Despite this, he does not appear to be in significant distress. He is not toxic. He is noted to have mild retractions when crying, with bilaterally coarse breath sounds without wheezes. Heart regular without murmurs or gallops. Abdomen: Liver edge palpable 3 cm below the right costal margin. A chest X-ray was obtained. View CXR: AP view. View CXR: Lateral view.

16 Ключові терміни: 16 Do you think this represents a pneumonia? The emergency department physician reads this as mild perihilar infiltrates. A diagnostic impression of a viral pneumonia is made, and the infant is hospitalized because of his young age and persistent tachypnea. The following morning, the radiologist reads the chest radiograph as showing borderline cardiomegaly with prominence of the right atrium and increased pulmonary vascularity. The right heart border appears to be prominent, but this initially was thought to be due to rotational artifact. The diffuse reticular markings fanning out from the hilum suggest pulmonary venous congestion but are difficult to distinguish from perihilar infiltrates. These findings are suggestive of congenital heart disease. This radiographic information prompts a cardiac work-up. The most important point here is to realize that a cardiac defect may be responsible for the infant's respiratory symptoms. Scrutinizing the chest radiograph for subtle signs of cardiac disease is important since, once cardiac disease is suspected, it is a simple matter of obtaining an echocardiogram. After admission to the wards, the infant develops worsening respiratory distress. A blood gas is obtained. On room air, an arterial blood gas shows ph 7.27, pco2 35, po2 76, HCO3 of 16. With 100% O2, the po2 increases to 138. An EKG shows right atrial enlargement with right axis deviation and right ventricular hypertrophy. An echocardiogram shows a membranous structure in the left atrium, a high atrial septal defect, and dilation of the right atrium and right ventricle. The right ventricular systolic pressure is elevated to 103 mm Hg. The diagnosis of cor triatriatum with secondary congestive heart failure is made, and the infant is started on digoxin and diuretics. He is referred to a cardiac surgeon for corrective surgery and does well postoperatively. A follow up chest radiograph taken a few months later shows a decrease in heart size and decreased pulmonary congestion. View follow-up CXR.

17 Ключові терміни: 17 Also present are surgical wires and metal clips in the area of the left atrium. There is some residual prominence of the pulmonary vasculature. Cor triatriatum is a rare congenital cardiac anomaly where the pulmonary veins enter an accessory chamber that joins the left atrium through a narrow opening. This accessory chamber may also directly communicate with the right atrium. In classical cor triatriatum, a membranous partition exists in the left atrium in the shape of a wind sock. View Cor Triatriatum diagram. The upper chamber (XC) of this partition receives blood from the pulmonary veins, and the distal chamber communicates with the mitral valve. The orifice diameter of the windsock ranges from less than 3 mm to about 1 cm. In a minority of cases, a patent foramen ovale or an atrial septal defect allows communication with the right atrium. Right ventricular hypertrophy and dilation are almost always present, and right atrial dilation occurs 25% of the time. Current theories suggest that the defect occurs because the common pulmonary vein fails to incorporate into the left atrium during cardiac embryogenesis. The clinical features of this anomaly are related to the pulmonary congestion and hypertension created by the membranous left atrial structure. When pulmonary venous blood flow becomes obstructed, the lungs reflect varying degrees of pulmonary edema and intraalveolar hemorrhage. Patients usually present within the first few years of life with a history of shortness of breath and frequent pulmonary infections and audible rales. Signs of pulmonary

18 Ключові терміни: 18 hypertension, including a loud pulmonic component of the second heart sound, right ventricular heave and pulmonary systolic ejection clicks are often present. The usual heart murmur is a soft, blowing,systolic murmur heard best at the left sternal border. The EKG usually reveals signs of right-sided heart overload such as right ventricular hypertrophy and right atrial enlargement. The chest radiograph often reveals pulmonary venous obstruction. Diffuse reticular pulmonary markings fan out from the hilum to involve the lower lung fields. Kerley B lines may also be present. The right heart border may reveal a double density suggestive of left atrial enlargement. Other findings include enlargement of the main pulmonary artery and right ventricular hypertrophy. Treatment of this disease involves management of congestive heart failure. Once patients reach this stage, they usually deteriorate fairly quickly despite medical management. Surgical intervention should be planned as soon as possible in symptomatic patients once the diagnosis is made. The operation of choice is usually correction under direct vision with cardiopulmonary bypass. The prognosis of cor triatriatum is related to the size of the orifice in the obstructing membrane. Without surgical correction, the average survival is about 3 months when the opening is less than 3 mm, and 16 years when the opening is greater than 3 mm. In those patients surviving operative correction, the prognosis is excellent. Acyanotic Congenital Heart Disease The Left-to-Right Shunt Lesions Atrial Septal Defect Atrial septal defects (ASDs) can occur in any portion of the atrial septum (secundum, primum, or sinus venosus), depending on which embryonic septal structure has failed to develop normally. Less commonly, the atrial septum may be nearly absent, with the creation of a functional single atrium. Isolated secundum ASDs account for 7% of congenital heart defects. The majority of cases of ASD are sporadic; autosomal dominant inheritance does occur as part of the Holt-Oram syndrome (hypoplastic or absent radii, 1st-degree heart block, ASD) or in families with secundum ASD and heart block. An isolated valve-incompetent patent foramen ovale (PFO) is a common echocardiographic finding during infancy. It is usually of no hemodynamic significance and is not considered an ASD; a PFO may play an important role if other structural heart defects are present. If another cardiac anomaly is causing increased right atrial pressure (pulmonary stenosis or atresia, tricuspid valve abnormalities, right ventricular dysfunction), venous blood may shunt across the PFO into the left atrium with resultant cyanosis. Because of the anatomic structure of the PFO, left-to-right shunting is unusual outside the immediate newborn period. In the presence of a large volume load or a hypertensive left atrium (secondary to mitral stenosis), the foramen ovale may be sufficiently dilated to result in a significant atrial left-to-right shunt. A valve-competent but probe-patent foramen ovale may be present in 15 30% of adults. An isolated PFO does not require surgical treatment, although it may be a risk for paradoxical (right to left) systemic embolization. Device closure of these defects is considered in adults with a history of thromboembolic stroke.

19 Ключові терміни: 19 Ostium Secundum Defect An ostium secundum defect in the region of the fossa ovalis is the most common form of ASD and is associated with structurally normal atrioventricular (AV) valves. Mitral valve prolapse has been described in association with this defect but is rarely an important clinical consideration. Secundum ASDs may be single or multiple (fenestrated atrial septum), and openings 2 cm in diameter are common in symptomatic older children. Large defects may extend inferiorly toward the inferior vena cava and ostium of the coronary sinus, superiorly toward the superior vena cava, or posteriorly. Females outnumber males 3:1 in incidence. Partial anomalous pulmonary venous return, most commonly of the right upper pulmonary vein, may be an associated lesion. PATHOPHYSIOLOGY The degree of left-to-right shunting is dependent on the size of the defect, the relative compliance of the right and left ventricles, and the relative vascular resistance in the pulmonary and systemic circulations. In large defects, a considerable shunt of oxygenated blood flows from the left to the right atrium. This blood is added to the usual venous return to the right atrium and is pumped by the right ventricle to the lungs. With large defects, the ratio of pulmonary to systemic blood flow (Qp : Qs) is usually between 2 : 1 and 4 : 1. The paucity of symptoms in infants with ASDs is related to the structure of the right ventricle in early life when its muscular wall is thick and less compliant, thus limiting the left-to-right shunt. As the infant becomes older and pulmonary vascular resistance drops, the right ventricular wall becomes thinner and the left-to-right shunt across the ASD increases. The large blood flow through the right side of the heart results in enlargement of the right atrium and ventricle and dilatation of the pulmonary artery. The left atrium may be enlarged, the left ventricle and aorta normal in size. Despite the large pulmonary blood flow, pulmonary arterial pressure is usually normal because of the absence of a high-pressure communication between the pulmonary and systemic circulations. Pulmonary vascular resistance remains low throughout childhood, although it may begin to increase in adulthood and may eventually result in reversal of the shunt and clinical cyanosis.

20 Atrioventricular Septal Defects (Ostium Primum and Atrioventricular Canal or Endocardial Cushion Defects) 20 CLINICAL MANIFESTATIONS. A child with an ostium secundum ASD is most often asymptomatic; the lesion may be discovered inadvertently during physical examination. Even an extremely large secundum ASD rarely produces clinically evident heart failure in childhood. In younger children, subtle failure to thrive may be present; in older children, varying degrees of exercise intolerance may be noted. Often, the degree of limitation may go unnoticed by the family until after surgical repair, when the child's growth or activity level increases markedly. The physical findings of an ASD are usually characteristic but fairly subtle and require careful examination of the heart, with special attention to the heart sounds. Examination of the chest may reveal a mild left precordial bulge. A right ventricular systolic lift is generally palpable at the left sternal border. A loud 1st heart sound and sometimes a pulmonic ejection click can be heard. In most patients, the 2nd heart sound is characteristically widely split and fixed in its splitting in all phases of respiration. Normally, the duration of right ventricular ejection varies with respiration, with inspiration increasing right ventricular volume and delaying closure of the pulmonary valve. With an ASD, right ventricular diastolic volume is constantly increased and the ejection time is prolonged throughout all phases of respiration. A systolic ejection murmur is heard; it is medium pitched, without harsh qualities, seldom accompanied by a thrill, and best heard at the left middle and upper sternal border. It is produced by the increased flow across the right ventricular outflow tract into the pulmonary artery, not by low-pressure flow across the ASD. A short, rumbling mid-diastolic murmur produced by the increased volume of blood flow across the tricuspid valve is often audible at the lower left sternal border. This finding, which may be subtle and is heard best with the bell of the stethoscope, usually indicates a Qp : Qs ratio of at least 2 : 1. DIAGNOSIS. The chest roentgenogram shows varying degrees of enlargement of the right ventricle and atrium, depending on the size of the shunt. The pulmonary artery is large, and pulmonary vascularity is increased. These signs vary and may not be conspicuous in mild cases. Cardiac enlargement is often best appreciated on the lateral view because the right ventricle protrudes anteriorly as its volume increases. The electrocardiogram shows volume overload of the right ventricle; the QRS axis may be normal or exhibit right axis deviation, and a minor right ventricular conduction delay (rsr pattern in the right precordial leads) may be present. The echocardiogram shows findings characteristic of right ventricular volume overload, including an increased right ventricular end-diastolic dimension and flattening and abnormal motion of the ventricular septum. A normal septum moves posteriorly during systole and anteriorly during diastole. With right ventricular overload and normal pulmonary vascular resistance, septal motion is reversed that is, anterior movement in systole or the motion may be intermediate so that the septum remains straight. The location and size of the atrial defect are readily appreciated by two-dimensional scanning, with a characteristic brightening of the echo image seen at the edge of the defect (T-artifact). The shunt is confirmed by pulsed and color flow Doppler. Patients with the classic features of a hemodynamically significant ASD on physical examination and chest radiography, in whom echocardiographic identification of an isolated secundum ASD is made, need not be catheterized before surgical closure, with the exception of an older patient, in whom pulmonary vascular resistance may be a concern. If pulmonary vascular disease is suspected, cardiac catheterization confirms the presence of the defect and allows measurement of the shunt ratio and pulmonary pressure. At catheterization, the oxygen content of blood from the right atrium will be much higher than that from the superior vena cava. This feature is not specifically diagnostic because it may occur with partial anomalous pulmonary venous return to the right atrium, with a ventricular septal defect (VSD) in the

21 Atrioventricular Septal Defects (Ostium Primum and Atrioventricular Canal or Endocardial Cushion Defects) 21 presence of tricuspid insufficiency, with AV septal defects associated with left ventricular to right atrial shunts, and with aorta to right atrial communications (ruptured sinus of Valsalva aneurysm). Pressure in the right side of the heart is usually normal, but small to moderate pressure gradients (<25 mm Hg) may be measured across the right ventricular outflow tract because of functional stenosis related to excessive blood flow. In children and adolescents, the pulmonary vascular resistance is almost always normal. The shunt is variable and depends on the size of the defect, but it may be of considerable volume (as high as 20 L/min/m 2 ). Cineangiography, performed with the catheter through the defect and in the right upper pulmonary vein, demonstrates the defect and the location of the right upper pulmonary venous drainage. Alternatively, pulmonary angiography demonstrates the defect on the levophase (return of contrast to the left side of the heart after passing through the lungs). COMPLICATIONS. Secundum ASDs are usually isolated, although they may be associated with partial anomalous pulmonary venous return, pulmonary valvular stenosis, VSD, pulmonary artery branch stenosis, and persistent left superior vena cava, as well as mitral valve prolapse and insufficiency. Secundum ASDs are associated with the autosomal dominant Holt-Oram syndrome. The gene responsible for this syndrome, situated in the region 12q21 q22 of chromosome 12, is TBX5, a member of the T-box transcriptional family. A familial form of secundum ASD associated with AV conduction delay has been linked to mutations in another transcription factor, Nkx2.5. Patients with familial ASD without heart block may carry a mutation in the transcription factor GATA4, located on chromosome 8p TREATMENT. Surgical or transcatheter device closure is advised for all symptomatic patients and also for asymptomatic patients with a Qp : Qs ratio of at least 2 : 1. The timing for elective closure is usually after the 1st yr and before entry into school. Closure carried out at open heart surgery is associated with a mortality rate of <1%. Repair is preferred during early childhood because surgical mortality and morbidity are significantly greater in adulthood; the long-term risk of arrhythmia is also greater after ASD repair in adults. Atrial septal occlusion devices are implanted transvenously in the cardiac catheterization laboratory ( Fig ). The results are excellent and patients are discharged the following day. With the latest generation of devices, the incidence of serious complications such as device erosion is 0.1% and can be decreased by identifying high-risk patients such as those with a deficient rim of septum around the device. In patients with small secundum ASDs and minimal left-to-right shunts, the consensus is that closure is not required. It is unclear at present whether the persistence of a small ASD into adulthood increases the risk for stroke enough to warrant prophylactic closure of all these defects. PROGNOSIS. ASDs detected in term infants may close spontaneously. Secundum ASDs are well tolerated during childhood, and symptoms do not usually appear until the 3rd decade or later. Pulmonary hypertension, atrial dysrhythmias, tricuspid or mitral insufficiency, and heart failure are late manifestations; these symptoms may initially appear during the increased volume load of pregnancy. Infective endocarditis is extremely rare, and antibiotic prophylaxis for isolated secundum ASDs is not recommended. The results after surgical or device closure in children with moderate to large shunts are excellent. Symptoms disappear rapidly, and growth is frequently enhanced. Heart size decreases to normal, and the electrocardiogram shows decreased right ventricular forces. Late right heart failure and arrhythmias are less frequent in patients who have had early surgical repair, becoming more common in patients who undergo surgery after 20 yr of age. Although early and midterm results with device closure are excellent, the long-term effects are not yet known. Reports of resolution of migraine headaches in patients after device closure of ASD or PFO are intriguing, suggesting a possible thromboembolic etiology; however, there are also paradoxical reports of patients whose migraines began or worsened after placement of one of these devices. Atrioventricular Septal Defects (Ostium Primum and Atrioventricular Canal or

22 Cyanotic Congenital Heart Disease 22 Endocardial Cushion Defects) The abnormalities encompassed by AV septal defects are grouped together because they represent a spectrum of a basic embryologic abnormality, a deficiency of the AV septum. An ostium primum defect is situated in the lower portion of the atrial septum and overlies the mitral and tricuspid valves. In most instances, a cleft in the anterior leaflet of the mitral valve is also noted. The tricuspid valve is usually functionally normal, although some anatomic abnormality of the septal leaflet is generally present. The ventricular septum is intact. An AV septal defect, also known as an AV canal defect or an endocardial cushion defect, consists of contiguous atrial and ventricular septal defects with markedly abnormal AV valves. The severity of the valve abnormalities varies considerably; in the complete form of AV septal defect, a single AV valve is common to both ventricles and consists of an anterior and a posterior bridging leaflet related to the ventricular septum, with a lateral leaflet in each ventricle. The lesion is common in children with Down syndrome and may occasionally occur with pulmonary stenosis. Transitional varieties of these defects also occur and include ostium primum defects with clefts in the anterior mitral and septal tricuspid valve leaflets, minor ventricular septal deficiencies, and, less commonly, ostium primum defects with normal AV valves. In some patients, the atrial septum is intact, but the inlet VSD simulates that found in the full AV septal defect. These defects are also commonly associated with deformities of the AV valves. Sometimes AV septal defects are associated with varying degrees of hypoplasia of one of the ventricles, known as either left- or right-dominant AVSD. If the affected ventricular chamber is too small, then surgical palliation, aiming for an eventual Fontan procedure, is similar to that for hypoplastic left or right heart syndromes. PATHOPHYSIOLOGY. The basic abnormality in patients with ostium primum defects is the combination of a left-to-right shunt across the atrial defect and mitral (or occasionally tricuspid) insufficiency. The shunt is usually moderate to large, the degree of mitral insufficiency is generally mild to moderate, and pulmonary arterial pressure is typically normal or only mildly increased. The physiology of this lesion is therefore similar to that of an ostium secundum ASD. In AV septal defects, the left-to-right shunt occurs at both the atrial and ventricular levels. Additional shunting may occur directly from the left ventricle to the right atrium because of absence of the AV septum. Pulmonary hypertension and an early tendency to increase pulmonary vascular resistance are common. AV valvular insufficiency increases the volume load on one or both ventricles. Some right-toleft shunting may also occur at both the atrial and ventricular levels and lead to mild but significant arterial desaturation. With time, progressive pulmonary vascular disease increases the right-to-left shunt so that clinical cyanosis develops. CLINICAL MANIFESTATIONS. Many children with ostium primum defects are asymptomatic, and the anomaly is discovered during a general physical examination. In patients with moderate shunts and mild mitral insufficiency, the physical signs are similar to those of the secundum ASD, but with an additional apical murmur caused by mitral insufficiency. A history of exercise intolerance, easy fatigability, and recurrent pneumonia may be obtained, especially in infants with large left-to-right shunts and severe mitral insufficiency. In these patients, cardiac enlargement is moderate or marked, and the precordium is hyperdynamic. Auscultatory signs produced by the left-to-right shunt include a normal or accentuated 1st sound; wide, fixed splitting of the 2nd sound; a pulmonary systolic ejection murmur sometimes preceded by a click; and a low-pitched, mid-diastolic rumbling murmur at the lower left sternal edge or apex, or both, as a result of increased flow through the AV valves. Mitral insufficiency may be manifested by a harsh (occasionally very high pitched) apical holosystolic murmur that radiates to the left axilla. With complete AV septal defects, heart failure and intercurrent pulmonary infection usually appear in infancy. During these episodes, minimal cyanosis may be evident. The liver is enlarged and the infant shows signs of failure to thrive. Cardiac enlargement is moderate to marked, and a systolic thrill is frequently palpable at the lower left sternal border. A precordial bulge and lift may be present as well. The 1st heart sound is normal or accentuated. The 2nd heart sound is widely split if the pulmonary flow is massive. A low-pitched, mid-diastolic rumbling murmur is audible at the lower left sternal border, and a pulmonary systolic ejection murmur is produced by the large pulmonary flow. The harsh apical holosystolic murmur of mitral insufficiency may also be present. DIAGNOSIS. Chest radiographs of children with complete AV septal defects often show moderate to severe cardiac enlargement caused by the prominence of both ventricles and atria. The pulmonary artery is large, and pulmonary vascularity is increased. The electrocardiogram in patients with a complete AV septal defect is distinctive. The principal abnormalities are (1) superior orientation of the mean frontal QRS axis with left axis deviation to the left upper or right upper quadrant, (2) counterclockwise inscription of the superiorly oriented QRS vector loop, (3) signs of biventricular hypertrophy or isolated right ventricular hypertrophy, (4) right ventricular conduction delay (RSR pattern in leads V 3 R and V 1 ), (5) normal or tall P waves, and (6) occasional prolongation of the P-R interval. shows signs of right ventricular enlargement with encroachment of the mitral valve echo on the left ventricular outflow tract; the abnormally low position of the AV valves results in a gooseneck deformity of the left ventricular outflow tract on both echocardiography and angiography. In normal hearts, the tricuspid valve inserts slightly more toward the apex than the mitral valve does. In AV septal defects, both valves insert at the same level because of absence of the AV septum. In complete AV septal defects, the ventricular septal echo is also deficient and the common AV valve is readily appreciated. Pulsed and color flow Doppler echocardiography will demonstrate left-to-right shunting at the atrial, ventricular, or ventricular to atrial levels and semiquantitate the degree of AV valve

23 Cyanotic Congenital Heart Disease 23 insufficiency. Echocardiography is useful for determining the insertion points of the chordae of the common AV valve and for evaluating the presence of associated lesions such as patent ductus arteriosus (PDA) or coarctation of the aorta. Selective left ventriculography will demonstrate deformity of the mitral or common AV valve and the distortion of the left ventricular outflow tract caused by this valve ( gooseneck deformity). The abnormal anterior leaflet of the mitral valve is serrated, and mitral insufficiency is noted, usually with regurgitation of blood into both the left and right atria. Direct shunting of blood from the left ventricle to the right atrium may also be demonstrated. TREATMENT. Ostium primum defects are approached surgically from an incision in the right atrium. The cleft in the mitral valve is located through the atrial defect and is repaired by direct suture. The defect in the atrial septum is usually closed by insertion of a patch prosthesis. The surgical mortality rate for ostium primum defects is very low. Surgical treatment of complete AV septal defects is more difficult, especially in infants with cardiac failure and pulmonary hypertension. Because of the risk of pulmonary vascular disease developing as early as 6 12 mo of age, surgical intervention must be performed during infancy. Correction of these defects can be accomplished in infancy, and palliation with pulmonary arterial banding is reserved for the subset of patients who have other associated lesions that make early corrective surgery too risky. The atrial and ventricular defects are patched and the AV valves reconstructed. Complications include surgically induced heart block requiring placement of a permanent pacemaker, excessive narrowing of the left ventricular outflow tract requiring surgical revision, and eventual worsening of mitral regurgitation requiring replacement with a prosthetic valve. PROGNOSIS. The prognosis for unrepaired complete AV septal defects depends on the magnitude of the left-toright shunt, the degree of elevation of pulmonary vascular resistance, and the severity of AV valve insufficiency. Death from cardiac failure during infancy used to be frequent before the advent of early corrective surgery. In patients who survived without surgery, pulmonary vascular obstructive disease or, more rarely, pulmonic stenosis usually developed. Most patients with ostium primum defects and minimal AV valve involvement are asymptomatic or have only minor, nonprogressive symptoms until they reach the 3rd 4th decade of life, similar to the course of patients with secundum ASDs. Late postoperative complications include atrial arrhythmias and heart block, progressive narrowing of the left ventricular outflow tract requiring surgical revision, and eventual worsening of atrioventricular valve regurgitation (usually on the left side) requiring replacement with a prosthetic valve. Cyanotic Congenital Heart Disease This is a 3 month old male infant who presents to the emergency department with a history of having episodes of excessive crying followed by limpness, cyanosis and fainting. He was born at 41 weeks of gestation by C-section because of failure to progress to a 23 year old mother G1P0. Apgar scores of 7 and 8 at 1 and 5 minutes, respectively. He had a two vessel cord and acrocyanosis. His cyanosis increased with crying and he had a grade 3/6 ejection systolic murmur along the upper left sternal border (ULSB). His oxygen saturations were 95% and stable. He was discharged from the hospital and followed in the office until this episode. He is now being hospitalized. Exam: VS T 37, P164, RR 64, oxygen saturation 83% on oxygen by nasal prongs. Weight 50th percentile. He is alert and active in mild respiratory distress, with visible cyanosis. HEENT exam is negative. His heart rhythm is tachycardic. He has a mild right precordial heave with a grade 3/6 ejection murmur at ULSB and a diminished 2nd heart sound. His lungs are clear. Liver and spleen are not enlarged. He has normal peripheral pulses with cyanotic nail beds and mucous membranes. An echocardiogram is obtained which identifies cyanotic congenital heart disease. This is confirmed at cardiac catheterization. He subsequently undergoes palliative surgery with improved oxygenation and appearance of a continuous murmur. He is discharged in stable condition to be followed on an outpatient basis and to undergo further corrective surgery at a later date.

24 Cyanotic Congenital Heart Disease 24 This diagram of the adult heart illustrates the structures that are affected by congenital heart diseases, with the estimated incidence of each disease per 1,000 live births indicated in parentheses. AC, aortic coarctation; AS, aortic stenosis; ASD, atrial septal defect; AVSD, atrioventricular septal defect; BAV, bicuspid aortic valve; DORV, double outlet right ventricle; Ebstein's, Ebstein's anomaly of the tricuspid valve; HLHS, hypoplastic left heart syndrome; HRHS, hypoplastic right heart; IAA, interrupted aortic arch; MA, mitral atresia; MS, mitral stenosis; PDA, patent ductus arteriosus; PS, pulmonary artery stenosis; PTA, persistent truncus arteriosus; TA, tricuspid atresia; TAPVR, total anomalous pulmonary venous return; TGA, transposition of the great arteries; TOF, tetralogy of Fallot; VSD, ventricular septal defect. (Image courtesy of F. Yeung, University of Toronto, Canada.) Cyanosis is a bluish discoloration of skin and mucous membranes. It results from reduced hemoglobin in blood of at least 3-5 gm/dl. Cyanosis can be secondary to cardiac, respiratory, hematologic and metabolic causes. Methemoglobinemia, decreased alveolar hypoventilation secondary to depressed respiratory center or obstruction of the respiratory passages, polycythemia, and hypoglycemia, shock, and sepsis may also cause cyanosis, or at least something that resembles cyanosis. It can be central or peripheral. Peripheral cyanosis is secondary to low cardiac output, in which acrocyanosis usually occurs with cool extremities and small pulse volume with bluish discoloration at the tip of the nose and fingers, and less in the mucous membranes. It is often difficult to differentiate pulmonary from cardiac causes of cyanosis in the newborn. A hyperoxy test may be helpful, whereby an arterial po2 is measured in room air, which is then compared to a arterial po2 measured in an FiO2 of about 90%-100% for about minutes. Respiratory problems with alveolar hypoventilation usually improve with pao2 measurements well above mmhg, whereas in right-to-left shunt cardiac lesions, the improvement in arterial po2 is very minimal. Echocardiogram and chest x-ray are useful in differentiating these causes. The above mentioned case represents a diagnostic and management problem. Classifying cyanotic congenital heart defects into those with increased vascularity with an accentuated second heart sound and those with decreased blood flow with a diminished second heart sound, can simplify the differential diagnosis to an extent. Chest x-ray findings and attention to the second heart sound may help. Lesions with increased or normal blood flow with accentuated second heart sounds include transposition of the great vessels, truncus arteriosis, total anomalous pulmonary venous return, single ventricle, single atrium, and hypoplastic left heart. Eisenmenger syndrome also falls into this category, but this is an acquired condition in which a patient with a left-to-right shunt and chronic CHF develops pulmonary hypertension and a subsequent right-to-left shunt. Those lesions with decreased blood flow and diminished second heart sound include tetralogy of Fallot or tetralogy of Fallot-like lesions, pulmonary atresia, tricuspid atresia, and Ebstein's malformation.

25 Cyanotic Congenital Heart Disease 25 In the diagram above, transposition of the great vessels is shown. This occurs when the trunco-conal septum does not spiral down. Instead, it descends straight down. As a result, the outflow of right ventricle is into the aorta and the outflow from the left ventricle is into the pulmonic trunk.in order for this system to work, there must be a connection between the system and pulmonic circulations. Sometimes this is through a ventricular septal defect or an atrial septal defect. In the diagram at the left, this is through a patent ductus arteriosus. Transposition of the great vessels is the most common cyanotic congenital heart disease in the newborn infant (tetralogy of Fallot is more common overall, but many tetralogy of Fallot cases present after the newborn period). Transposition represents 4%-5% of all congenital heart defects. The aorta arises from the right ventricle and pulmonary artery from the left ventricle, with the aorta positioned anterior and to the right of the pulmonary artery. It is incompatible with life unless a communication exists between systemic and pulmonary circulation, as the two circulations are in parallel (and independent). During the newborn period, the PDA and patent foramen ovale (PFO) maintain this communication. As the PDA starts to close and the PFO by itself is inadequate in size, the patient develops intense cyanosis, and the patient becomes tachypneic. On auscultation, the second heart sound is greater in intensity, as the aortic valve is anterior. A heart murmur may not be present unless other associated lesions are present. An electrocardiogram may show right ventricular hypertrophy, but this is non-specific since RVH is present in normal newborns. Chest x-ray shows increased pulmonary vascular markings and a narrow mediastinal shadow secondary to a small thymus, sometimes giving the appearance of "egg on side" or "apple on a string" appearance. Echocardiography confirms the diagnosis and delineates the other associated lesions. Inadequate mixing between systemic and pulmonary circuits represents a medical emergency and a prostaglandin E1 infusion which maintains ductus arteriosus patency (to preserve mixing) may be lifesaving, followed by balloon atrial septostomy (Rashkind procedure). Surgical management consists of an arterial switch procedure (aorta and pulmonary artery are anastomosed to the correct ventricle), which is the operation of choice. The atrial switch (atrial baffling) such as Senning or Mustard procedures are no longer done because of the development of later complications. Survival without surgery is unlikely. The arterial switch procedure offers the best prognosis with a mortality of about 5%.

26 Cyanotic Congenital Heart Disease 26 This diagram depicts the features of Tetralogy of Fallot:1. Ventricular septal defect; 2. Overriding aorta; 3. Pulmonic stenosis; 4. Right ventricular hypertrophy. The obstruction to right ventricular outflow creates a right-to-left shunt that leads to cyanosis. Tetralogy of Fallot constitutes 4%-9% of congenital heart disease and is the most common cyanotic congenital heart disease when considering all age groups together. Tetralogy of Fallot and pulmonary atresia with ventricular septal defect consist of: a) ventricular septal defect, b) pulmonary stenosis, c) overriding of the aorta, and d) right ventricular hypertrophy. Approximately 25% have a right-sided aortic arch, and about 4% have a coronary artery anomaly. The degree of cyanosis depends on the degree of pulmonic outflow obstruction. This is quite variable, from a slight obstruction, to severe obstruction with pulmonary atresia. Pulmonary atresia constitutes about 18% of the children with tetralogy of Fallot. The major right ventricular outflow obstruction in tetralogy of Fallot is infundibular stenosis. With mild stenosis, there may be congestive heart failure in infancy, also known as "pink tetralogy of Fallot." As infundibular stenosis increases, progressive cyanosis develops (due to less pulmonary blood flow), and infants and children may develop cyanotic or hypoxic spells, which consist of sudden onset of increased cyanosis, excessive crying, hypoxemia, acidosis, dyspnea, fainting, rarely seizures, and occasionally death if untreated. During these episodes (called "Tet" spells), there is increased right-to-left shunting (with less pulmonary flow), and decreased systemic vascular resistance. Older infants and children may assume a squatting position during playtime or long walks which increases systemic vascular resistance and decreases right to left shunting, increasing their oxygenation. Clinical examination shows a loud systolic ejection murmur from the right ventricular outflow obstruction at the left sternal border conducted to the upper sternal border towards the suprasternal notch. The second pulmonary sound may be diminished, but the aortic component may be loud, as the aorta is anterior.

27 Cyanotic Congenital Heart Disease 27 The electrocardiogram shows the non-specific right ventricular hypertrophy. Chest x-ray shows decreased pulmonary vascular markings (reduced pulmonary perfusion) and right ventricular hypertrophy with a leftward apex. There is an absence or decreased main pulmonary artery segment, which may give the appearance of a "boot shaped heart." Echocardiography demonstrates a ventricular septal defect with an overriding of the aorta, pulmonic stenosis, right ventricular hypertrophy, and in about 25% of cases, a right aortic arch (i.e., the aorta goes over the right mainstem bronchus instead of the left) is also present. Cardiac catheterization is done in cases in which the anatomy of the defect is not clear on echocardiogram. Management during the newborn period consists of administration of prostaglandin E1 when the infant is markedly cyanotic and pulmonary blood flow is ductus dependent. This is followed by a systemic artery to pulmonary artery shunt (Blalock-Taussig shunt). Treatment of hypercyanotic spells is directed towards improving pulmonary blood flow. These include oxygen, knee/chest position, morphine, intravenous fluids, sodium bicarbonate, propranolol (beta-blocker), or increasing systemic vascular resistance by administration of drugs, such as phenylephrine. Total surgical correction of the defect is performed under cardiopulmonary bypass, and it can now be performed in young infants from 3-6 months of age or earlier. Prognosis is good with total correction. However, the majority of them still have residual defects and some of them may need reoperation and life long medical follow up. Truncus arteriosus consists of a single arterial vessel arising from the heart, positioned over a ventricular septal defect, supplying systemic, coronary and pulmonary circulations. It accounts for about 1%-4% of the congenital heart defects. Associated anomalies are common, such as DiGeorge syndrome. Symptomatology depends upon the amount of pulmonary blood flow. With increased blood flow, symptoms of congestive heart failure such as tachypnea, cyanosis, retractions, etc., develop. There may be a systolic murmur at the left sternal border or an apical aortic ejection click. A diastolic murmur of truncal insufficiency may be heard along the left sternal border. The electrocardiogram may show right or left or combined ventricular hypertrophy. Chest x-ray shows an enlarged heart and increased pulmonary vasculature. There may be a right aortic arch (25%). The echocardiogram shows a truncal root overriding VSD, and pulmonary arteries arising from the trunk. Cardiac catheterization may be indicated when the anatomic features are not clear on echocardiography. Management consists of treatment of congestive heart failure followed by surgery. Surgical correction consists of closure of the VSD, separation of the pulmonary arteries from the trunk and anastomosing them through a conduit from the right ventricle (Rastelli procedure). The prognosis is poor in untreated cases. After surgery, they will need long term follow up as they will eventually need to have the conduit graft replaced.

28 Cyanotic Congenital Heart Disease 28 Total anomalous pulmonary venous return (TAPVR) occurs in about 1%-2% of patients with congential heart disease. There are four types of TAPVR causing left-to-right shunt: Supracardiac, cardiac, infracardiac, and mixed. In the supracardiac type, pulmonary veins join to form a common vein which drains into the SVC. In the cardiac type, the common pulmonary veins drain into the right atrium directly or via the coronary sinus. In the infracardiac type, the common pulmonary vein courses downward through the diaphragm into the portal vein, which then drains via hepatic veins into the inferior vena cava. Total Anomalous Pulmonary Venous Return TAPVR and PAPVR Must have ASD for survival All have anatomical L to R shunt at atrial level All have functional R to L shunt of oxygenated blood to right side of heart Two Types l Partial (PAPVR) l Mild physiologic abnormality l Usually asymptomatic l Total (TAPVR) l Serious physiologic abnormalities Partial Anomalous Pulmonary Venous Drainage (PAPVR) General l One of the four pulmonary veins may drain into right atrium l Mild or no physiologic consequence l Associated with ASD l Sinus venosus or ostium secundum types Total Anomalous Pulmonary Venous Drainage (TAPVR) l All have shunt through lungs to R side of heart l All must also have R to L shunt for survival l Obligatory ASD to return blood to the systemic side l All are cyanotic l Identical oxygenation in all four chambers l Types l Supracardiac l Cardiac l Infracardiac l Mixed l Supracardiac Type Type I l Most common (52%) l Pulmonary veins drain into vertical vein (behind left pulmonary artery) to left brachiocephalic vein to SVC l DDx: VSD with large thymus l Supracardiac Type 1 X-ray Findings l Snowman heart = dilated SVC+ left vertical vein l Shunt vasculature 2 increased return to right heart

29 Cyanotic Congenital Heart Disease 29 l Enlargement of right heart 2 volume overload l Cardiac Type Type II l Second most common: 30% l Drains into coronary sinus or RA l Coronary sinus more common l Increased pulmonary vasculature l Overload of RV leads to CHF after birth l 20% of I s and II s survive to adulthood l Remainder expire in first year l Infracardiac Type Type III l Percent of total: 12% l Long pulmonary veins course down along esophagus l Empty into IVC or portal vein (more common) l Vein constricted by diaphragm as it passes through esophageal hiatus l Severe CHF (90%) 2 obstruction to venous return l Cyanotic 2 right to left shunt through ASD l Associated with asplenia (80%), or polysplenia l Prognosis = death within a few days l Mixed Type Type IV l Percent of total: 6% l Mixtures of types I III Anomalous pulmonary venous return could be total or partial. An atrial septal defect is necessary for survival, since the oxygenated blood (from the pulmonary veins) must somehow reach the left side of the heart. Symptomatology depends on the amount of mixing and whether or not the pulmonary veins are obstructed. Cyanosis and signs and symptoms of congestive heart failure develop and progress rapidly. There may be a grade 2/6 systolic ejection flow murmur heard along the left sternal border, or it may be absent. The electrocardiogram shows right ventricular hypertrophy and right atrial hypertrophy. Chest x- ray shows increased pulmonary vascular markings or even edema, and the heart may be normal in size or minimally enlarged. The echocardiogram may show right ventricular volume overload, and a color-flow Doppler study may help in locating the common pulmonary venous channel and its drainage. If the resolution is poor, cardiac catheterization and angiocardiography may help in delineating the anomaly further. Treatment consists of correction of the defect by surgery. If surgery is delayed and there is inadequate mixing, palliative balloon septostomy may be performed. Prognosis is good after surgery. Prognosis is poor in neonates with obstructive TAPVR. Long term follow up is needed to assess restenosis and late arrhythmias.

30 Cyanotic Congenital Heart Disease 30 Tricuspid atresia consists of an absence or atretic tricuspid valve and a hypoplastic right ventricle. Blood from the right atrium enters the left atrium through an atrial septal defect or foramen ovale. They may have associated lesions such as TGA, VSD, PDA, right aortic arch, pulmonic stenosis or atresia. Communication between right and left circulation is essential to sustain life. Symptomatology depends on the amount of pulmonary blood flow. In the absence of a VSD, as the PDA closes, patients may develop intense cyanosis, tachypnea and tachycardia. The electrocardiogram usually shows left axis deviation (very unlike the RVH seen in normal newborns) and right atrial hypertrophy and left-ventricular hypertrophy. Chest x-ray may show increased or decreased pulmonary blood flow depending on the shunt and a normal or mildly increased heart size. Echocardiography usually delineates these abnormalities and very rarely a cardiac catheterization may be needed. Prostaglandin E1 may be life saving in infants with low oxygen saturation with duct dependent pulmonary blood flow. This is followed by a modified Blalock Taussig anastomosis. If the interatrial communication is narrow (small PFO/ASD) then a balloon or blade atrial septostomy is performed. Surgical correction initially consists of a bilateral Glenn procedure (superior vena cava to right pulmonary artery shunt) followed by an inferior vena cava anastomosis to the right pulmonary artery through an intra or extra cardiac baffle (modified Fontan procedure). Prognosis is good after surgery but patients will need multiple surgeries with associated morbidity such as pleural effusion, ascites, arrhythmia and mortality. Ebstein anomaly is characterized by downward displacement of the septal and posterior leaflets of the tricuspid valve which are attached to the right ventricular septum. The anterior leaflet is elongated and is displaced downward within the right ventricular cavity causing "atrialization of the right ventricle" (i.e., the

31 Cyanotic Congenital Heart Disease 31 displaced downward within the right ventricular cavity causing "atrialization of the right ventricle" (i.e., the right ventricle is small). There is usually a PFO or an ASD or PS (pulmonic stenosis). Cyanosis depends up on the right to left shunt. Auscultation may reveal a triple or quadruple gallop rhythm and a split second heart sound. A pansystolic murmur of tricuspid insufficiency or an ejection murmur of PS may be heard. The electrocardiogram shows a right bundle branch block pattern, giant P waves and sometimes first degree AV block or WPW syndrome (delta wave). Chest x-ray shows a huge right atrium and gross cardiomegaly. Echocardiography reveals the lesions of Ebstein anomaly and only rarely is cardiac catheterization needed. Treatment is mainly palliative and there are no good surgical options. In older patients, tricuspid annuloplasty and rarely tricuspid valve replacement may be performed. Prognosis depends on the severity of the lesion. Prognosis is good with mild lesions and poor with severe lesions with other associated anomalies/malformations. Hypoplastic left heart syndrome consists of a combination of mitral stenosis or atresia, severe aortic stenosis or atresia, and a small left ventricle. Systemic circulation depends on the patency of the ductus. These infants may appear reasonably well at birth until either the pulmonary vascular resistance drops or the PDA closes. They then present with shock, variable cyanosis, poor pulses, poor perfusion and CHF. A systolic murmur may or may not be present. Chest x-ray shows increase vascularity and EKG may show RV hypertrophy. Echocardiography is diagnostic. Early management consists of administration of PGE1 and treatment of CHF. Surgery consists the Norwood surgical procedure and a few centers perform cardiac transplantation for this lesion. Prognosis is guarded. Questions 1. A two day old cyanotic infant with a grade 3/6 ejection systolic murmur is noted to have decreased pulmonary vascular markings on chest x-ray and left axis deviation on EKG. The most likely diagnosis is: a. Tetralogy of Fallot b. Transposition of Great Vessels c. Truncus Arteriosus d. Tricuspid Atresia 2. A 2 year old infant is noted to have mild cyanosis who assumes a squatting position during long walking. He is noted to have increasing fussiness followed by increasing cyanosis, limpness and unresponsiveness. The most likely underlying lesion is: a. Hypoplastic left heart b. Transposition of the Great Vessels c. Anomalous Pulmonary Venous Return d. Tetralogy of Fallot e. Aspiration with obstruction to air passages 3. An infant with a marked cyanotic congenital heart defect with decreased pulmonary vascularity should be treated with: a. Digoxin b. Indomethacin c. Prostaglandin E1 d. Epinephrine

32 Cyanotic Congenital Heart Disease Cyanosis is produced by the presence of deoxygenated hemoglobin of at least: 2. a. 1-2 gm/dl 3. b. 3-5 gm/dl 4. c. 6-8 gm/dl 5. d gm/dl 5. A "tet spell" or "blue" spell of tetralogy of Fallot is treated with all of the following except: a. oxygen b. knee chest position c. morphine d. digoxin e. propranolol f. phenylephrine g. sodium bicarbonate 6. Pulmonary vascularity is increased in all of the following except: a. TAPVR b. Tricuspid atresia c. TGV d. Hypoplastic left heart 7. Pulmonary vascularity is decreased in all of the following except: a. Tetralogy of Fallot b. Pulmonary atresia c. TAPVR d. Tricuspid atresia Answers to questions 1.d, 2.d, 3.c, 4.b, 5.d, 6.b, 7.c