Congenital Heart Disease - Jarzembowski Flashcards
What is the most common etiology of congenital heart defects?
idiopathic (90%)
DiGeorge Syndrome (22q11) is associated with what congenital heart defects?
What is the mutated gene?
ASD, VSD, and outflow tract obstruction
Name the four major categories of CHD classification
- Late cyanotic (L->R shunt)
- Acyanotic (obstruction)
- Cyanotic (R->L shunt)
- Valvular regurgitation
Name the 4 late cyanotic disorders. What is the direction of the shunt?
- ASD
- VSD
- AVSD
- PDA
Left-to-right shunt
Name 3 acyanotic (obstruction) CHDs
- Pulmonary stenosis
- Aortic stenosis
- Coarctation
Name 5 cyanotic disorders.
What is the direction of the shunt?
- Tetralogy of Fallot
- Transposition of the great vessels
- Truncus
- TV Atresia
- TAPVR
right-to-left shunt
What type of defect is an Ebstein anomaly?
valvular regurgitation
Explain the process of late cyanosis
- Initial L->R shunt results in no cyanosis
- However, shunt increases pulmonary circulation beyond its normal capacity
- result is pulmonary hypertension and right ventricular hypertrophy
- Increased right-sided pressure (due to PHT and RVH) reverses the direction of shunt flow
- L->R shunting results in (late) cyanosis
What is plexogenic pulmonary hypertension?
What is its relative prevalance in: PDA, ASD, and VSD?
Pathology of pulmonary vasculature due to increased flow and pressure in pulmonary circulation, resulting in:
- medial hypertrophy
- intimal proliferation
- plexiform lesions (irreversible damage)
VSD > PDA >> ASD
What is an atrial setpal defect?
Where is the defect usually located?
Interatrial opening, present thoughout the cardiac cycle (distint from PDA). May be asymptomatic until adulthood, often responsible for paradoxial embolism. ~10% lead to pulmonary hypertension.
Most common: secundum @ fossa ovalis (90%)
primum adjacent to AV valves (5%)
sinus venosus near SVC entrance (5%)
Compare ASD and PFO in terms of the following:
- Prevalence
- Structure
- Shunting
- Complications
- Prevalence
- ASD: rare
- PFO: present in 1/3 of people
- Structure
- ASD: fenestrated or deficient fossa ovale
- PFO: remnant opening of FO
- Shunting
- ASD: L->R
- PFO: no shunting (back pressure closes opening)
- Complications
- ASD: pulmonary HT, right-sided heart failure
- PFO: paradoxical emboli, decompression sickness, migraines (?)
What is a ventricular septal defect? Where does it commonly occur?
What is the treatment?
Most common congenital heart anomaly
Interventricular opening between LV and RV
90% occur at the membranous VS, but 70% are associated with other anomalies
Treatment: surgery by 1 y.o.. May spontaneously (10%) close
Compare: membranous vs. muscular VSD
Membranous
- defect usually large
- requires surgical closure before 1 y.o.
Muscular
- defect is usually small
- >60% spontaneously close - therefore most do not need surgery
- may have multiple muscular VSD (so-called “swiss cheese septum”)
A harsh, continuous, “machinery-like” murmur is a classic physical exam finding of what?
Patent ductus artiosus (PDA)
Is PDA usually seen alone or with other defects?
How might this be functionally useful?
Usually seen in isolation (90%)
Often necessary for survival with other defects (AV or PV atresia, other defects)
When does the DA functionally close? When is it structurally closed? What might be used to delay its closure?
Functional close: ~12 hours after birth
Structureal: ~3 months after birth
PGE2 delays closure
What is an atrioventricular septal defect? What two types are seen and where do they occur?
What is the treatment?
Deficient AV septum, associated with MV and TV anomalies
Partial: ASD and cleft MV with MR
Complete: AVSD and common AV valve
Early surgical correction is required
What underlying condition presents with complete AVSD in approximately 40% of cases?
Down syndrome
How many valve leaflets are typically seen in a complete AVSD?
five (5)
Explain why R->L shunts cause early cyanosis
Why do we also typically see paradoxical emboli and increased incidence of decompression sickness?
R->L shunt dumps deoxygenated blood into systemic circulation and decreases pulmonary blood flow
R->L shunt bypasses the lungs, where emboli and gas bubbles are normally filtered out
What is the most common form of cyanotic congenital heart disease?
Tetraolgy of Fallot
What is Tetralogy of Fallot?
Anteriosuperior displacement of the infundibular septum, leading to:
- ventricular septal defect
- subpulmonary stenosis
- overriding aorta
- right ventricular hypertophy
Explain the differences between the following (think shunt direction). What accounts for the differences?
- pink tetralogy
- classic tetralogy
- PA-VSD
- Pink tetralogy: L->R shunt, moderate subpulmonary stenosis
- classic: R->L, severe subpulmonary stenosis
- RA-VSD: R->L, complete subpulmonary stenosis
Difference: severity of subpumonary stenosis
What congential heart defect typically shows a boot-shaped heart on CXR?
Tetralogy of Fallot
Why is pulmonary congestion not typically seen with Tetralogy of Fallot?
What is the treament for ToF?
The R->L shunt does not typically damage or congest the lungs because the lungs are protected by the subpulmonary stenosis.
Surgery - pulmonary outlet does not grow with the child, therefore the condition will get worse over time.
Transposition of the great arteries:
Describe
What are its major sequelae?
How is it managed?
- Aorta arising from the RV, pulmonary artery arising from the LV - systemic and pulmonary circulations are separate.
- Results in right ventricular hypertrophy and pulmonary hypertension (unless pulmonary stenosis also present)
- Management:
- If VSD also present, usually stable (35%, no intervention required)
- If VS intact (65%) prompt surgical intervention (de-transpose vessels or introduce VSD
Truncus Arteriosus:
Define
What is its etiology?
Describe the clinical sequelae?
What genetic defect is TA often associated with?
The aorta and pulmonary artery originate from a common truncal artery. Outflow to both tracts consists of mixed blood from both the LV and RV
Results from an incomplete separation of the embryologic truncus into two distinct outflow tracts (aorta and pulmonary artery)
Increased pulmonary blood pressure and flow may lead to pulmonary hypertension
Often associated with DiGeorge Syndrome (22q11DS)
What is Tricuspid Atresia?
How does it come about?
What is the resulting effect on the structure of the heart?
What is its general prognosis?
Complete occlusion of the tricuspid orifice
Due to unequal division of the AV canal -> tricuspid valve is absent, the mitral valve is large. Causes RV hypoplasia.
Survival depends on coexisting ASD/PFO and VSD. Symptomatic patients tend to have a very high mortality rate. Surgery often not an option due to lack of enough RV tissue to work with. Heart transplant is a more appealing option.
What is Total Anomalous Venous Return?
Give some anatomical variations that are typically seen.
What is the etiology?
Pulmonary veins do not directly drain into the LA -> leads to LA hypoplasia. Requires ASD/PFO for oxygenated blood to reach systemic circulation.
Examples:
- Connect back to SVC via anomalous vertical vein
- Single vein connecting to the LA (instead of the usual 4)
- Anomalous vein connects to system venous circulation inferiorly (below the diaphragm)
Aortic coarctation
Define, including the two major types
What is the typical clinical presentation (including details for each type), and treatment options
Constriction or narrowing of the aorta
Two types:
- Preductal/infantile: tubular hypoplasia with PDA
- Postductal/adult: ridgelike infoldin of the aorta at the remnant ligamentum arteriosum (no PDA present)
Clinical presentation and treatment:
- preductal/infantile: lower body cyanosis
- requires surgery during neonatal period
- postductal/adult: rib notching (seen on CXR) due to increased flow through vertebral collaterals, symptoms more or less severe depending on degree of narrowing and location
- surgical correction necessity based on location: upper > lower
Define pulmonary stenosis
What sequelae are seen in isolated PV stenosis?
What sequelae are seen in PV stenosis with intact VS?
Pulmonary valve obstruction due to hypoplasia, dysplasia, or an abnormal number of cusps.
Isolated PV stenosis: RV dilation and hypertrophy, post-stenotic injury to pulmonary artery (due to turbulance/pressure). May be asymptomatic until adulthood.
PV stenosis with intact VS: hypoplastic RV and TV. PDA required to get blood to the lungs.
What long-term changes to the heart are seen with pulmonary stenosis?
- pulmonary artery dilation
- RVH
- RA dilation
Define aortic stenosis (AS)
Describe the results of an isolated AS
Aortic valve obstruction due to hypoplasia, dysplasia, or an abnormal number of cusps (similar to PS)
Isolated: LV hypertrophy and LA dilation. Symptoms vary with severity of stenosis. A systolic murmur can be heard.
What is aortic stenosis with an intact VS called?
Describe.
hypoplastic left heart syndrome
hypoplastic mitral valve and left ventricle -> depends on PDA for survival
Multiple staged surgeries required (often >3 surgeries over 5 years)
Ebstein Anomaly (of tricuspid valve)
Define
What are its typical secondary effects?
What named arrhythmia is this associated with?
Inferiorly displaced and adherent septal and posterior tricuspid valve leaflets. May include a redundant anterior leaflet and a dilated annulus (leading to tricuspid regurgitation). May be asymptomatic until adulthood.
Secondary effects: RV and RA dilation
Associated with arrhythmias, including WPW Syndrome
What are some typical risks in cardiac surgery? What about transplantation?
Cardiac surgery risks:
- bleeding
- infection
- death
- stroke
- long-term arteriosclerosis (due to endothelial damage during surgery)
- fibrosis
Transplant risks:
- Same as cardiac surgery plus…
- rejection
- infection
- post-transplant lymphoproliferative disease (and other malignancies)
What late-presenting effects or risks might be seen with CHD?
Endocarditis
hyperviscosity (polycythemia, etc)
Pulmonary hypertension and shunt reversal
Childbearing risk
Post-surgical patholgies
What is the Eisenmeiger Complex?
Gradual development of pulmonary hypertension resulting in reversal of a shunt from L->R to R->L
What is the most common congenital heart defect (CHD)?
What is the least worrisome (clinically) CHD?
VSD
ASD
