Congenital Heart Disease Flashcards
(26 cards)
The most common form of ASD
Ostium secundum defect
- Sinus venosus defect - 5 to 10%
- Ostium primum - partial atrioventricular canal defects
- ostium secundum - which are the most prevalent (80%)
The most common age to close asymptomatic ASD is_______
4-5 years
- patients who are symptomatic may require earlier intervention
- **paradoxical embolism during pregnancy
Acceptable treatment for aortic valve stenosis with a hypoplastic ventricle
- Intubation
- inotropic support
- prostaglandin to maintain ducrtal patency for systemic blood flow
- Norwood procedure
- first part of the staged single ventricle pathway
- In the presence of hypoplastic LV
- isolated aortic valvotomy should NOT be performed
The most common location for a coarctation of the aorta?
Distal to the left subclavian
- defined as a luminal narrowing in the aorta that causes obstruction to blood flow
The treatment of choice for recurrent COA (after surgical repair) in a preschool aged child
Balloon dilatation
- Children tounger than 6 months with native COA should be treated with surgical repair, while those requiring intervention at later stages may be ideal for balloon dilatation or primary stent implantation
- Catheter based therapy - for those cases of restenosis following either surgical or primary endovascualr manangement
Which of the following is true surgical emergency in a newborn?
Total anomalous pulmonary venous connection
- occurs in 1 to 2% of all cardiac malformations
- abnormal drainage of the pulmonary veins into the right heart, whether through connections into the atrium or into its triubutaries
- The only mechanism by which oxygenated blood can return to the left heart is through an ASD
The bidirectional Glenn procedure is used to correct
Tricuspid atresia
- cavopulmonary anastomosis
- end to side right pulmonary artery to superior vena cava
- first stage to final fontan repair
- essentially bypassed the right heart and allowed separation of the pulmonary and systemic circulations
Hypoplastic left heart syndrome is surgically treated with
-
Norwood procedure with a right ventricle (RV) to pulmonary artery conduit (Sano shunt)
- diminishes the diastolic flow created by BT shunt and may augment coronary perfusion
-
Bilateral pulmonary artery banding and stent placement in the patent ductus arteriosus
- Hybrid (does not require cardiopulmonary bypass)
-
Norwood procedure with a Balock-Taussig (B-T) shunt
- bypasses the LV by creating a single outflow vessel, the neoarta, which arises from the RV
The arterial switch operation for transposition of the great vessels is best performed
Within 2 weeks of birth
- The most important consideration is the timing of surgical repair. (before the LV loses its ability to pump angainst systemic load)
- LV can be retrained
- preliminary pulmonary artery banding and aortopulmonary shunt
- Mechanical assist device for a few days while it recovers ability to manage systemic pressures
- Echocardiography can be used to assess left ventricular performance and guide operative planning in these circumstances
Tetralogy of fallot
- malalignment ventricular septal defect
- dextroposition of the aorta
- right ventricular outflow tract obstruction
- Right ventricular hypertrophy
The most commonly recommended age for correction of a TOF is
Neonate younger than 3 months
- generally a B-T shunt, may still be preferred with an unstable neonate younger than 3 months, when an extracardiac conduit is required because of an anomalous left anterior descending coronary artery or severe pulmonary atresia, significant branch pulmonary artery hypoplasia or severe noncardiac anomalies coexist with TOF
Most common type of VSD to require surgical correction
Perimembranous
- 80% of cases
- these defects involve the membranous septum and include the malalignment defects in TOF
The best predictor of spontaneous closure of a VSD?
Age at diagnosis
- inversely related to the age at which the defect is observed
- infants at 1 month have an 80% incidence of psontaneous closure
- 12 months of age has only 25% chance
- Large defects and those in severly symptomatic neonates should be repaired during infancy to relieve symptoms
Cardiac abnormality, that becomes a serious problem at birth
Tricuspid atresia
- Pulmonary circulation becomes important at birth.
- Septal defects and the ductus arteriosus can be tolerated by the newborn child, but tricuspid atresia, pulmonic valve stenosis or other right ventricular outflow obstruction forces a right to left shunt
Cor triatriatum is ____________
Three atria where the left atrium is divided by a diaphragm separating the chamber receiving pulmonary return from the chamber draining through the mitral valve into the LV
- if the communication between the superior and inferior chmabers is less than 3mm, patients are symptomatic during the first year life
Flow across a VSD id dependent upon
Pulmonary and sytemic vascular resistance and defect size
- The size od the VSD determines the initial pathophysiology of the disease
- Small restrictive VSDs offer significant resistance to the passage of blood across the defect
- RV pressure is either normal or minimally elevated
A child with a large VSD and no cardiac lesion can be expected to develop
- Cyanosis
- Failure thrive
- Increased susceptibility to lower respiratory tract infection
- large vebtricular defects result in dilation but minimal hypertrophy due to decreased afterload
- VSD produces left to right shunt because systemic vascular resistance is greater than pulmonary vascular resistance
Beyond early childhood, high pulmonary blood flow is most apt to produce
Diminished exercise tolerance
- High pulmonary blood flow beyond infancy may produce little disability for a period of time
- diminished exercise tolerance may be subtle
- With the volume overloading in the RV, ventricular dilatation is more common than ventricular hypertrophy
The most important diagnostic assessment modality for evaluating infants and children with congenital heart disease
Transthoracic echocardiogram
- Chest Xray may define heart size and electrocardiograms indicate cardiac rhythm
- transthoracic and subcostal echocardiograms provide information on cardiac structure and function\
- transesophageal is not required for children
- Good acoustic window
The major determinant of operatibility in patients who have a VSD is ________________
The pulmonary vascular resistance
- When pulmonary vascular resistance exceeds 1/2 of the systemic resistance = INOPERABLE
- those patients who have severe pulmonary vascular resistance increase their cardiac output by right to left shunting across the defect
- If the defect is closed, they have no mechanism to increase cardiac output with exercise
Transplant free survival after norwood with B-T shunt (system to pulmonary) versus Sano shunt (RV to pulmonary shunt) in patients with hypoplastic left heart syndrome
Worse at 12 months bor B-T shunt, but equal at longer term follow up
A premature infant is discovered to have a patent ductur arteriosus with moderate respiratory distress. The Infant does not improve after 48 hours of medical manangement with fluid restriction, diuretics, and respiratory. The next step in management is
Indomethacin
- Prostaglandins oppose contraction of smooth muscle that obliterates the ductus
- Indomethacin is a prostaglandin inhibitor, and given IV, leads to closure of the ducts
Type of VSD
Types of VSD
- perimembranous
- atrioventricular canal
- outlet or suprecristal
- muscular
VSD refers to a hole between the left and RVs. these defects are common, comprising 20 to 30% of all cases
VAry in sizr from 3mm to 4mm to more than 3 cm
During left thoracotomy for repair of PDA the BP is 70/22. Immediately after the placement of a clip across the duct the blood pressure will
Closure of the duct immediately increases diastolic systemic blood pressurem while leaving systolic pressure unchanged
