Congenital Heart Disease

Question 1

The most common form of ASD

Answer 1

Ostium secundum defect

• Sinus venosus defect - 5 to 10%
• Ostium primum - partial atrioventricular canal defects
• ostium secundum - which are the most prevalent (80%)

Question 2

The most common age to close asymptomatic ASD is_______

Answer 2

4-5 years

• patients who are symptomatic may require earlier intervention
• **paradoxical embolism during pregnancy

Question 3

Acceptable treatment for aortic valve stenosis with a hypoplastic ventricle

Answer 3

• 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

Question 4

The most common location for a coarctation of the aorta?

Answer 4

Distal to the left subclavian

• defined as a luminal narrowing in the aorta that causes obstruction to blood flow

Question 5

The treatment of choice for recurrent COA (after surgical repair) in a preschool aged child

Answer 5

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

Question 6

Which of the following is true surgical emergency in a newborn?

Answer 6

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

Question 7

The bidirectional Glenn procedure is used to correct

Answer 7

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

Question 8

Hypoplastic left heart syndrome is surgically treated with

Answer 8

• 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

Question 9

The arterial switch operation for transposition of the great vessels is best performed

Answer 9

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

Question 10

Tetralogy of fallot

Answer 10

• malalignment ventricular septal defect
• dextroposition of the aorta
• right ventricular outflow tract obstruction
• Right ventricular hypertrophy

Question 11

The most commonly recommended age for correction of a TOF is

Answer 11

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

Question 12

Most common type of VSD to require surgical correction

Answer 12

Perimembranous

• 80% of cases
• these defects involve the membranous septum and include the malalignment defects in TOF

Question 13

The best predictor of spontaneous closure of a VSD?

Answer 13

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

Question 14

Cardiac abnormality, that becomes a serious problem at birth

Answer 14

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

Question 15

Cor triatriatum is ____________

Answer 15

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

Question 16

Flow across a VSD id dependent upon

Answer 16

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

Question 17

A child with a large VSD and no cardiac lesion can be expected to develop

Answer 17

• 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

Question 18

Beyond early childhood, high pulmonary blood flow is most apt to produce

Answer 18

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

Question 19

The most important diagnostic assessment modality for evaluating infants and children with congenital heart disease

Answer 19

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

Question 20

The major determinant of operatibility in patients who have a VSD is ________________

Answer 20

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

Question 21

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

Answer 21

Worse at 12 months bor B-T shunt, but equal at longer term follow up

Question 22

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

Answer 22

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

Question 23

Type of VSD

Answer 23

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

Question 24

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

Answer 24

Closure of the duct immediately increases diastolic systemic blood pressurem while leaving systolic pressure unchanged

Question 25

Truncus arteriosus

Answer 25

• Truncal valves most commyly have three leaflets (60%) but occassionally, bicuspid and rare
• Patients usual;ly present with mild to moderate cyanosis and congestive heart failure in the neonnatal period
• There is a continuous left to right shunt
• A pansystolic murmur may be noted at the left sternal border and occasionally a diastolic murmur
• Repair should be undertaken in the neonatal period or as soon as the diagnosis is established to prevent the development of pulmonary hypertension due to pulmonary circulation
• The presence of eisenmegerization is the only absolute contraindication to correction

Question 26

Closure of ASD in adults

Answer 26

• Atrial arrythmias are common postoperatively
• Postopertaive mortality is significantly higher with increasing age
• Secundum ASD closure is more commonly performed using transcatheter approach compared with surgical approaches
  *