cardiovascular

• Congenital heart diseases


  About 8% of term newborns are born with a congenital cardiovascular abnormality. This rate is even higher in preterm infants. Overall, these disorders affect equal numbers of male and female infants, but specific defects show a tendency toward sex differences. The usual cause is failure of a heart structure to progress beyond an early stage of embryonic development.
• Maternal rubella is an example of an infection known to lead to disorders such as patent ductus arteriosus, pulmonary or aortic stenosis, atrial or ventricular septal defects, or pulmonary stenosis
• Atrial and ventricular septal defects can also be familial. If a parent has an aortic stenosis, atrial septal defect, ventricular septal defect, or pulmonic stenosis, the incidence of this occurring also in the child is about 10% to 15%.
• Cyanotic and acyanotic disorders


  Formerly, congenital heart disorders were classified based on the physical sign of cyanosis
• Disorders with increased pulmonary blood flow


  • Involve blood flow from the left side of the heart, which is under greater pressure, to the right side of the heart, which is under less pressure, through some abnormal opening or connection between the two systems or the great arteries.
• Ventricular septal defect (VSD)


  An opening is present in the septum between the two ventricles. Because pressure in the left ventricle is greater than that in the right ventricle, blood shunts from left to right across the septum. This impairs the effort of the heart because blood that should go into the aorta and out to the body is shunted back into the pulmonary circulation, resulting in right ventricular hypertrophy/enlargement and increased pressure in the pulmonary artery.
• Ventricular septal defect


  • May not be evident at birth. With incomplete opening of the alveoli, there is still high pulmonary artery resistance, so little blood is shunted through the defect. At about 4 to 8 weeks, as shunting begins, the infant demonstrates easy fatigue, and a loud, harsh pansystolic murmur becomes evident along the left sternal border at the third or fourth interspace.
• Diagnosis of VSD


  Based on examination by echocardiography with color flow Doppler or MRI, which reveals right ventricular hypertrophy and possibly pulmonary artery dilatation from the increased blood flow. An ECG will also reveal right ventricular hypertrophy.
• Ventricular septal defect


  Up to 85% of VSDs are so small they close spontaneously. Those that are moderate in size may be closed during cardiac catheterization. Larger ones (>3 mm) require open heart surgery. This is usually scheduled before 2 y/o to prevent pulmonary artery hypertension. Closure is important because if the defect is left open, cardiac failure from the artery hypertension can result.
• Children may receive prophylactic antibiotics to prevent bacterial endocarditis for 6 months afterward. If there are no complications, children can expect to participate in normal activities after the repair.
• Atrial septal defect (ASD)


  An abnormal communication between the two atria, allowing blood to shift from the left to the right atrium. It is more common in girls. Blood flow is from left to right (oxygenated to deoxygenated) because of the stronger contraction of the left side of the heart. This causes an increase in the ventricular hypertrophy and increased pulmonary artery blood flow.
• Atrial septal defect


  • There are two types: ostium primum (ASD1), where the opening is at the lower end of the septum, and ostium secundum (ASD2), where the opening is near the center of the septum. ASD2 defects may be asymptomatic and not discovered until infection from recirculating blood occurs.
• Diagnosis of ASD


  A harsh systolic murmur is heard over the second or third interspace (the pulmonic area) because of the extra amount of shunted blood that crosses the pulmonic valve. As the volume of blood crossing it causes the pulmonic valve to close consistently later than the aortic valve, the second heart sound will be auscultated as split (fixed splitting).
• Surgery to close the ASD is done electively between 1 and 3 years of age. Closure is important because without it, a child is at risk for infectious endocarditis and eventual heart failure. It is particularly important that ASDs be repaired in girls, because they can cause emboli during pregnancy.
• With uncomplicated surgery, children can expect a normal quality and length of life.
• Patent ductus arteriosus (PDA)


  The ductus arteriosus is an accessory fetal structure that connects the pulmonary artery to the aorta. If it fails to close at birth, blood will shunt from the aorta (oxygenated blood) to the pulmonary artery (deoxygenated blood) because of the increased pressure in the aorta. This causes increased pressure in the pulmonary circulation from the extra shunted blood, leading to right ventricle hypertrophy and ineffective heart action.
• Patent ductus arteriosus


  • PDAs are twice as common in girls as boys and occur at a higher incidence at higher altitudes. In preterm infants, the incidence may be as high as 20% to 60% and accounts for about 10% of all heart disease.
• Diagnosis of PDA


  On physical examination, the child usually has a wide pulse pressure. A typical continuous (systolic and diastolic) "machinery" murmur can be heard at the upper left sternal border or under the left clavicle in older children. In newborns, the murmur may not be quite so characteristic, perhaps a short grade II or III harsh systolic sound. An ECG is generally normal, although it may show ventricle enlargement if the shunt is large. Echocardiography provides good visualization of the patent ductus.
• Treatment of PDA

  If it does not close spontaneously, an infant may be prescribed IV indomethacin or ibuprofen, prostaglandin inhibitors. These lower the PGE1 level and encourage ductus closure. If medical management fails, the disorder can be closed by cardiac catheterization when the child is 6 months to 1 year of age. Exceptionally large defects can be closed surgically by ductal ligation.
• Increased oxygenation and increased calcium are important for closure of the ductus arteriosus.
• Pulmonary stenosis


  • Narrowing of the pulmonary valve or the pulmonary artery just distal to the valve. Inability of the right ventricle to evacuate blood by way of the pulmonary artery because of the obstruction leads to right ventricular hypertrophy.
• Diagnosis of pulmonary stenosis

  Infants may be asymptomatic or have signs of mild (right-sided) heart failure. If the narrowing is severe, cyanosis may be present. A typical systolic ejection murmur, grade IV or V crescendo-decrescendo in quality, can be heard, usually loudest at the upper left sternal border. An ECG or echocardiography will reveal right ventricular hypertrophy.
• Aortic stenosis


  • Stenosis or stricture of the aortic valve prevents blood from passing freely from the left ventricle of the heart into the aorta. Because the heart cannot force blood through the strictured valve, increased pressure and hypertrophy of the left ventricle occur. If the left ventricular pressure becomes acute, pressure in the left atrium also increases, resulting in back-pressure in pulmonary veins and possibly pulmonary edema.
• Diagnosis of aortic stenosis

  Most children are asymptomatic, but physical assessment generally reveals a typical murmur, a rough systolic sound heard loudest in the second right interspace (the aortic space). The murmur may be transmitted to the right shoulder, clavicle, and up the vessels of the neck. An ECG or echocardiography will reveal left ventricular hypertrophy.
• Treatment of aortic stenosis

  Stabilization with a beta-blocker or a calcium channel blocker may be necessary to reduce cardiac hypertrophy before the defect is corrected. Some children will need artificial valve replacement for correction. If a prosthetic valve is used, children generally continue to receive anticoagulation or antiplatelet therapy and antibiotic prophylaxis against endocarditis.
• Coarctation of the aorta


  • A narrowing of the lumen of the aorta due to a constricting band, accounts for about 6% of instances of congenital heart disease. It occurs more frequently in boys than in girls and is the leading cause of congestive heart failure in the first few months of life. There are two locations in which this commonly occurs: preductal, between the subclavian artery and the ductus arteriosus, and postductal, distal to the ductus arteriosus.
• Effects of coarctation of the aorta


  Because it is difficult for blood to pass through, blood pressure increases proximal to the coarctation and decreases distal to it. This results in increased blood pressure in the heart and upper portions of the body as pressure in the subclavian artery increases. Elevated upper body blood pressure produces headache and vertigo. Epistaxis (nosebleed) and cerebrovascular accident can occur from this dangerously elevated blood pressure.
• If the coarctation is slight, absence of palpable femoral pulses may be the only symptom. For this reason, always include evaluation of femoral pulses in all initial newborn assessments and admission inspections to newborn nurseries.
• Coarctation of the aorta

  Constriction occurs between the subclavian artery and the ductus arteriosus (preductal) or distal to the ductus arteriosus (postductal)
• Coarctation of the aorta

  Blood pressure increases proximal to the coarctation and decreases distal to it
• Increased upper body blood pressure


  Produces headache and vertigo
• Absence of palpable femoral pulses may be the only symptom of a slight coarctation
• Collateral arteries enlarge and may be seen on the ribs as obvious nodules as the child with coarctation of the aorta grows older
• Disorders with decreased pulmonary blood flow

  Involve some type of obstruction to blood flow in the pulmonary artery
• Tetralogy of Fallot (TOF)

  Four anomalies: pulmonary stenosis, VSD, dextroposition of the aorta, and hypertrophy of the right ventricle
• Tetralogy of Fallot


  1. Conal septum displaced to the right creating pulmonary stenosis

  2. Conal septum 'pulls' the aorta to the right causing dextroposition

  3. Incomplete ventricular septum leads to VSD

  4. Pulmonary stenosis causes pressure buildup in the right side of the heart, leading to right ventricular hypertrophy
• Newborns with Tetralogy of Fallot may not exhibit high degree of cyanosis immediately after birth, but cyanosis begins as they become more active
• Polycythemia occurs in Tetralogy of Fallot as the body attempts to provide enough red blood cells to supply oxygen
• Complications of polycythemia in Tetralogy of Fallot include thrombophlebitis, embolism, and cerebrovascular accident
• Management of coarctation of the aorta


  1. Interventional angiography (balloon catheter) or surgery

  2. Drug therapy (digoxin, diuretics) to reduce severity of congestive heart failure before surgery

  3. Surgical repair usually scheduled by 2 years of age