26-28 Flashcards
- Congenital heart diseases
- etiology
- types
- Environmental and genetic factors contribute to the development of congenital heart disease.
- Congenital heart diseases are divided into two types; acyanotic and cyanotic.
- The left-to right shuts and obstructive stenotic lesions are acyanotic generally Oxygenated blood from the left heart (left atrium or left ventricle) or the aorta shunts to the right heart (right atrium or right ventricle) or the pulmonary artery through an opening or communication between the 2 sides.
- while right to left shunts are cyanotic.
Varying amounts of deoxygenated venous blood are shunted to the left heart (right-to-left shunt), reducing systemic arterial oxygen saturation.
Acynotic Congenital heart diseases include:
- ventricular septal defect
- Arterial septal defect
- patent ductus arteriosus
- Endocardial cushion defect
Cyanotic Congenital heart diseases include:
- Tetralogy of Fallot
- Transposition of the Great Arteries
- Tricuspid atresia
- Truncus Arteriosus
- Total anomalous pulmonary venous return
- Hypoplastic left heart syndrome
-Arterial septal defect
Atrial septal defect
ASDs represent 10% of all congenital heart defects, the most common being foramen ovale remaining open. Some flow through the foramen ovale is normal just after birth, however it should usually close within a week for birth. ASDs are very rarely symptomatic, even in large shunts. A soft systolic ejection murmur can sometimes be detected, as can a fixed split S2 sound.
Treatment is rarely needed, if a significant shunt still exists at the age of 3, then treatment may be indicated through surgery.
- An atrial septal defect (ASD) is an opening in one of several parts of the interatrial septum, causing a left-to-right shunt.
- Small atrial communications often close spontaneously, but larger ones do not, causing right atrial and ventricular overload and ultimately pulmonary artery hypertension, elevated pulmonary vascular resistance, and right ventricular hypertrophy; supraventricular tachycardia, atrial flutter, or atrial fibrillation may also occur.
- ASDs can allow emboli from the veins to enter the systemic circulation (paradoxical embolization), causing arterial occlusion (eg, stroke).
- Auscultation typically reveals a grade 2 to 3/6 midsystolic murmur and a widely split, fixed S2; these findings may be absent in infants.
- Moderate to large ASDs should be closed, typically between ages 2 years and 6 years, using a transcatheter device when possible.
-Patent ductus arteriosus
-patent ductus arteriosus: As with foramen ovale, the ductus arteriosus is part of the fetal vasculation. It connects the aorta to the pulmonary artery, allowing blood to bypass the non-functioning lungs in-utero.
Failure of the DA to close is known as patent ductus arteriosus, causing a left to right shunting of blood and increasing pulmonary blood flow. PDAs account for 5-10% of all congenital heart failures.
Symptoms as always depend on the size of the shunt, however the big risk here is an increase in pulmonary pressure, possibly leading to pulmonary hypertension and eventually heart failure.
Physical examination shows a widened pulse pressure, and a continuous machine-like murmur which can be heard in the left infraclavicular area. Ductus arteriosus should close within 2 days of birth.
Treatment is with diuretics initially, and then coil embolization or a PDA closure device later if required. Medication can also be used to induce constriction of a PDA, including indomethacin, ibuprofen and acetaminophen (paracetamol)
- Patent ductus arteriosus (PDA) is a persistence of the fetal connection (ductus arteriosus) between the aorta and pulmonary artery after birth. In the absence of other structural heart abnormalities or elevated pulmonary vascular resistance, shunting in the PDA will be left to right (from aorta to pulmonary artery). Symptoms may include failure to thrive, poor feeding, tachycardia, and tachypnea. A continuous murmur at the upper left sternal border and bounding pulses are common. Diagnosis is by echocardiography. Administration of a cyclo-oxygenase inhibitor (ibuprofen lysine or indomethacin) with or without fluid restriction may be tried in premature infants with a significant shunt, but this therapy is not effective in term infants or older children with PDA. If the connection persists, surgical or catheter-based correction is indicated.
- At birth, the rise in PaO2 and decline in prostaglandin concentration cause closure of the ductus arteriosus, typically beginning within the first 10 to 15 hours of life. If this normal process does not occur, the ductus arteriosus will remain patent
- Patent ductus arteriosus (PDA) is a persistence after birth of the normal fetal connection (ductus arteriosus) between the aorta and pulmonary artery, resulting in a left-to-right shunt.
- Manifestations depend on the size of the PDA and the age of the child, but a continuous murmur is characteristic and, if loud, has a “machinery sounding” quality.
- Premature infants may have respiratory distress or other serious complications (eg, necrotizing enterocolitis).
- Over time, a large shunt causes left heart enlargement, pulmonary artery hypertension, and elevated pulmonary vascular resistance, ultimately leading to Eisenmenger syndrome if untreated.
- For premature infants with hemodynamically significant PDA, give a cyclo-oxygenase (COX) inhibitor (eg, ibuprofen lysine or indomethacin).
- Surgical closure may benefit patients with a hemodynamically significant PDA in whom medical therapy has failed.
- For full-term infants and older children, COX inhibitors are usually ineffective, but a catheter-delivered occlusion device or surgery typically provides long-term correction of this anomaly.
-Tetralogy of Fallot
Tetralogy of Fallot consists of 4 features: a large ventricular septal defect, right ventricular outflow tract obstruction and pulmonic valve stenosis, right ventricular hypertrophy, and over-riding of the aorta. Symptoms include cyanosis, dyspnea with feeding, poor growth, and hypercyanotic “tet” spells (sudden, potentially lethal episodes of severe cyanosis). A harsh systolic murmur at the left upper sternal border with a single 2nd heart sound (S2) is common. Diagnosis is by echocardiography. Definitive treatment is surgical repair.
- Tetralogy of Fallot involves a large ventricular septal defect (VSD), right ventricular outflow tract and pulmonary valve obstruction, and over-riding of the aorta.
- Pulmonary blood flow is decreased, the right ventricle hypertrophies, and unoxygenated blood enters the aorta via the VSD.
- Manifestations depend on the degree of right ventricle outflow obstruction; severely affected neonates have marked cyanosis, dyspnea with feeding, poor weight gain, and a harsh grade 3 to 5/6 systolic ejection murmur.
- The murmur comes from the pulmonary stenosis; the VSD shunt is silent.
- Hypercyanotic spells are sudden episodes of profound cyanosis and hypoxia that may be triggered by a fall in oxygen saturation (eg, during crying, defecating), decreased systemic vascular resistance (eg, during playing, kicking legs), or sudden tachycardia or hypovolemia. The murmur diminishes or disappears during a spell.
- Give neonates with severe cyanosis an infusion of prostaglandin E1 to open the ductus arteriosus.
- Place infants with hypercyanotic spells in the knee-chest position and give oxygen; sometimes, opioids (morphine or fentanyl), volume expansion, sodium bicarbonate, beta-blockers (propranolol or esmolol), or phenylephrine may help.
- Repair surgically at 2 to 6 months or earlier if symptoms are severe.
-Tricuspid atresia
Tricuspid atresia is absence of the tricuspid valve accompanied by a hypoplastic right ventricle. Associated anomalies are common and include atrial septal defect, ventricular septal defect, patent ductus arteriosus, pulmonic valve stenosis, and transposition of the great arteries. Presenting signs include cyanosis or signs of heart failure. The first heart sound (S1)is single and may be accentuated. The 2nd heart sound (S2) is usually single. Most infants have a murmur, the nature of which depends on the presence of associated anomalies. Diagnosis is by echocardiography. Cardiac catheterization may be needed. Definitive treatment is surgical repair.
- The tricuspid valve is absent, and the right ventricle is hypoplastic; these defects are fatal unless there is an opening between the atria along with a ventricular septal defect and/or patent ductus arteriosus.
- Infants with decreased pulmonary blood flow have progressively worsening cyanosis; infants with increased pulmonary blood flow usually have heart failure (eg, tachypnea, dyspnea with feeding, poor weight gain, diaphoresis).
- Relieve severe cyanosis by giving prostaglandin E1 infusion to keep the ductus arteriosus open.
- Definitive treatment requires staged operations.
-Total anomalous pulmonary venous return
In total anomalous pulmonary venous return, the pulmonary veins do not connect to the left atrium. Instead, the entire pulmonary venous return enters the systemic venous circulation through one or more persistent embryologic connections. If there is no obstruction to pulmonary venous return, cyanosis is mild and patients may be minimally symptomatic. Severe obstruction of the pulmonary venous return may occur, resulting in severe neonatal cyanosis, pulmonary edema, and pulmonary hypertension. Diagnosis is by echocardiography. Surgical repair is required.
- treatment:
- Surgical repair
- Medical treatment of heart failure (eg, diuretics, digoxin, angiotensin-converting enzyme inhibitors) before surgery
Neonates with total anomalous pulmonary venous return with obstruction require emergent surgical repair. In older infants, heart failure should be treated, followed by surgical repair as soon as the infant is stabilized.
Surgical repair consists of creating a wide anastomosis between the pulmonary venous confluence and the posterior wall of the left atrium. Ligation of the vein decompressing the confluence into the systemic venous circulation is important to prevent a postoperative left-to-right shunt. The repair is different for return to the coronary sinus, in which case the coronary sinus is unroofed into the left atrium and its opening to the right atrium is closed.
- Congenital heart failure
- Newborn screening
Newborn screening
Manifestations of congenital heart disease may be subtle or absent in neonates, and failure or delay in detecting critical congenital heart disease, particularly in the 10 to 15% of neonates who require surgical or inpatient medical treatment in the first hours or days of life, may lead to neonatal mortality or significant morbidity.
-Universal screening for critical congenital heart disease using pulse oximetry is recommended for all neonates before hospital discharge. The screening is done when infants are ≥ 24 hours old and is considered positive if ≥ 1 of the following is present:
-Any oxygen saturation measurement is < 90%.
The oxygen saturation measurements in both the right hand and foot are < 95% on 3 separate measurements taken 1 hour apart.
-There is > 3% absolute difference between the oxygen saturation in the right hand (preductal) and foot (postductal) on 3 separate, paired measurements taken 1 hour apart.
All neonates with a positive screening result should undergo a comprehensive evaluation for congenital heart disease and other causes of hypoxemia (eg, various respiratory disorders, central nervous system depression, sepsis) typically including a chest x-ray, ECG, echocardiography, and often blood testing. Sensitivity of pulse oximetry screening is slightly
- Congenital heart failure
- Newborn screening
Newborn screening
Manifestations of congenital heart disease may be subtle or absent in neonates, and failure or delay in detecting critical congenital heart disease, particularly in the 10 to 15% of neonates who require surgical or inpatient medical treatment in the first hours or days of life, may lead to neonatal mortality or significant morbidity.
-Universal screening for critical congenital heart disease using pulse oximetry is recommended for all neonates before hospital discharge. The screening is done when infants are ≥ 24 hours old and is considered positive if ≥ 1 of the following is present:
-Any oxygen saturation measurement is < 90%.
The oxygen saturation measurements in both the right hand and foot are < 95% on 3 separate measurements taken 1 hour apart.
-There is > 3% absolute difference between the oxygen saturation in the right hand (preductal) and foot (postductal) on 3 separate, paired measurements taken 1 hour apart.
All neonates with a positive screening result should undergo a comprehensive evaluation for congenital heart disease and other causes of hypoxemia (eg, various respiratory disorders, central nervous system depression, sepsis) typically including a chest x-ray, ECG, echocardiography, and often blood testing. Sensitivity of pulse oximetry screening is slightly
-Ventricular septal defect
-Ventricular septal defect
This is a hole between the left and right ventricle, through the ventricular septum. As the left side of the heart is always under greater pressure than the right side, blood is pushed from the left to the right. Small VSDs can be asymptomatic, but the typical finding is a pansystolic murmur, heard best at the lower left sternal border, sometimes with a thrill. There may also be a splitting of S2 depending on the size of the shunt.
1⁄3 of VSDs will spontaneously close, initial treatment is diuretics with or without digoxin to reduce heart load. If the infant continues to fail to develop, surgery may be required to close the VSD.
- A ventricular septal defect (VSD) is an opening in the interventricular septum, causing a shunt between ventricles. Large defects result in a significant left-to-right shunt and cause dyspnea with feeding and poor growth during infancy. A loud, harsh, holosystolic murmur at the lower left sternal border is common. Recurrent respiratory infections and heart failure may develop. Diagnosis is by echocardiography. Defects may close spontaneously during infancy or require surgical repair.
- Ventricular septal defect (VSD) is an opening in the interventricular septum, causing a left-to-right shunt.
- Over time, large left-to-right shunts cause pulmonary artery hypertension, elevated pulmonary artery vascular resistance, right ventricular pressure overload, and right ventricular hypertrophy, which ultimately cause shunt direction to reverse, leading to Eisenmenger syndrome.
- Larger defects cause symptoms of heart failure at age 4 to 6 weeks.
-Typically, a grade 3 to 4/6 holosystolic murmur at the lower left sternal border is audible shortly after birth.
Infants who do not respond to medical treatment of heart failure or have poor growth should have surgical repair during the first few months of life; even asymptomatic children with large VSDs should have repair during the first year of life.
Atrioventricular Septal Defect
-Endocardial cushion defect
Also known as atrioventricular canal defects, this is a complete or partial failure of the septum to fuse with the endocardial cushion causing abnormal atrioventricular valves, a ventricular septal defect and an atrial septal defect. In effect, you end up with almost two chambers instead of the four, connected by a pathological common valve.
This is a very severe congenital malformation, and symptoms of heart failure develop due to the increased pulmonary vascular resistance within the first two months. Treatment is diuretics (with or without digoxin) and then surgical repair which is almost always required. This defect is common in children with Down Syndrome.
- Atrioventricular (AV) septal defect consists of an ostium primum type atrial septal defect and a common AV valve, with or without an associated inlet (AV septal type) ventricular septal defect (VSD). These defects result from maldevelopment of the endocardial cushions. Patients with no VSD component or a small VSD and good AV valve function may be asymptomatic. If there is a large VSD component or significant AV valve regurgitation, patients often have signs of heart failure, including dyspnea with feeding, poor growth, tachypnea, and diaphoresis. Heart murmurs, tachypnea, tachycardia, and hepatomegaly are common. Diagnosis is by echocardiography. Treatment is surgical repair for all but the smallest defects.
- An atrioventricular (AV) septal defect may be complete, transitional, or partial; the majority of patients with the complete form have Down syndrome.
- A complete AV septal defect involves a large ostium primum atrial septal defect (ASD), a ventricular septal defect (VSD), and a common AV valve (often with significant regurgitation), all resulting in a large left-to-right shunt at both atrial and ventricular levels and enlargement of all 4 cardiac chambers.
- A partial AV septal defect also involves an ASD, but the common AV valve is partitioned into 2 separate AV orifices and there is no VSD, resulting in enlargement of the right heart chambers because of a large atrial shunt but no ventricular shunt.
- A transitional AV septal defect involves an ostium primum ASD, a common AV valve, and a small- or moderate-size VSD.
- Complete AV septal defect with a large left-to-right shunt causes signs of heart failure by age 4 to 6 weeks.
- Symptoms in partial AV septal defects vary with the degree of mitral regurgitation; if mild or absent, symptoms may develop during adolescence or early adulthood, but infants with moderate or severe mitral regurgitation often have manifestations of heart failure.
-Symptoms in transitional AV septal defect fall on a spectrum, depending on the size of the VSD.
Defects are repaired surgically between age 2 to 4 months or 1 to 3 years, depending on the specific defect and severity of symptoms.
Coarctation of the Aorta
- Coarctation of the aorta is a localized narrowing of the aortic lumen that results in upper-extremity hypertension, left ventricular hypertrophy, and malperfusion of the abdominal organs and lower extremities. Symptoms vary with the anomaly’s severity and range from headache, chest pain, cold extremities, fatigue, and leg claudication to fulminant heart failure and shock. A soft bruit may be heard over the coarctation site. Diagnosis is by echocardiography or by CT or MR angiography. Treatment is balloon angioplasty with stent placement, or surgical correction.
- Coarctation of the aorta is a localized narrowing of the lumen, typically in the proximal thoracic aorta just beyond the left subclavian artery and before the opening of the ductus arteriosus.
- Manifestations depend on severity of coarctation but typically involve pressure overload proximal to the coarctation, leading to heart failure, and hypoperfusion distal to the coarctation.
- Severe coarctation can manifest in the neonatal period with acidosis, renal insufficiency, and shock, but mild coarctation may not be apparent until an adolescent or adult is evaluated for hypertension or diminished femoral pulses.
- There is typically a blood pressure gradient between upper and lower extremities, an easily distinguished amplitude differential between the upper and lower extremity pulses, and a grade 2 to 3/6 ejection systolic murmur, sometimes most prominent in the left interscapular area.
- For symptomatic neonates, infuse prostaglandin E1 to reopen the constricted ductus arteriosus.
- Correct coarctation surgically or using balloon angioplasty with or without stent placement.
Bicuspid Aortic Valve
- Bicuspid aortic valve is the presence of only two (rather than the normal three) valve cusps.
- Patients with bicuspid aortic valve are predisposed to developing infective endocarditis, aortic regurgitation, and/or aortic stenosis. Bicuspid aortic valve can also be associated with dilation of the aortic root or ascending aorta and coarctation of the aorta.
- Treatment is by surgical repair of stenotic valves. Regurgitant valves are treated with surgery.
Eisenmenger Syndrome
-Pulmonary vascular resistance
Eisenmenger syndrome is a complication of uncorrected large intra-cardiac or aortic to pulmonary artery left-to-right shunts.
-Increased pulmonary resistance may develop over time, eventually leading to severe pulmonary hypertension, bidirectional shunting with progressively increasing right-to-left shunting. Cyanosis and hypoxia inevitably lead to multiple complications discussed below. Physical findings vary depending on the underlying defect and the stage of the pathophysiologic abnormalities. Diagnosis is based on echocardiography or advanced imaging and cardiac catheterization. Once Eisenmenger syndrome occurs, the increased pulmonary vascular resistance and pulmonary hypertension are irreversible, precluding primary correction of the original defect. Therefore, treatment is generally supportive, but heart and lung transplantation may be an option when symptoms are severe. Endocarditis prophylaxis is recommended.
- Cardiac anomalies that involve large intracardiac left-to-right shunts often eventually cause increased pulmonary resistance, which first causes bidirectional shunting and ultimately right-to-left shunting (shunt reversal).
- With shunt reversal, deoxygenated blood enters the systemic circulation, causing hypoxia and its complications (eg, clubbing of fingers and toes, secondary polycythemia); polycythemia may cause hyperviscosity, stroke, or other thromboembolic disorders, and/or hyperuricemia.
- Symptoms usually do not occur until age 20 to 40 years in patients with pre-tricuspid shunting; in patients with a post-tricuspid shunt, symptoms can occur during the first few years of life.
- Symptoms include cyanosis, syncope, dyspnea during exertion, fatigue, chest pain, palpitations, atrial and ventricular arrhythmias, hemoptysis and right heart failure.
- Doing a corrective operation for the underlying cardiac anomaly at the appropriate age should prevent Eisenmenger syndrome.
- There is no specific treatment once the syndrome develops, other than heart and lung transplantation, but drugs that may lower pulmonary vascular resistance (eg, prostacyclin analogs, endothelin antagonists, phosphodiesterase-5 inhibitors) are useful.
Pulmonary vascular resistance is the resistance against blood flow from the pulmonary artery to the left atrium
