Congenital Heart Disease Flashcards
What is the most common congenital anomaly?
Congenital Heart Disease (CHD)
○ Occurs in almost 1% of live births (8 in 1000)
T/F not all Congenital Heart Diseases are
serious and many go undetected for years
T
Environmental Factors causing CHD
○ Maternal illness
■ Such as diabetes, rubella, systemic lupus
erythematosus (SLE)
○ Maternal intake of teratogenic agents
■ Such as Isotretinoin, anticonvulsants,
lithium, etc.
○ Some evidence to suggest paternal age may
be a risk factor
Genetic Factors for CHD:
○ Certain chromosomal abnormalities are strongly associated with CHD.
■ Trisomy 21, Trisomy 18, Trisomy 13, Monosomy X (Turner Syndrome, 45 X)
■ These abnormalities account for only about 5% of CHD patients
○ Other cases involve microscopic deletions on chromosomes or
single-gene mutations. These can affect other organs too, not just heart.
Congenital heart abnormalities can be classified as either
○ Cyanotic
○ Acyanotic
Acyanotic conditions can further be classified into
● Left-to-Right Shunts
● Obstructive Lesions
Cyanotic Heart Defects include:
○ Tetralogy of Fallot
○ Transposition of the Great Arteries
○ Tricuspid Atresia (rare)
○ Pulmonary Atresia (rare)
Pathophysiology of Cyanotic Heart Anomalies:
○ These anomalies allow for varying amounts of deoxygenated venous
blood to be shunted to the left heart (right-to-left shunt).
■ Results in reduced systemic arterial oxygen saturation
Complications of persistent cyanosis can include _____
polycythemia,
clubbing, thromboembolism (such as stroke), etc.
Left-to-Right Shunt (acyanotic) defects include:
■ Ventricular Septal Defect
■ Atrial Septal Defect (such as Patent Foramen Ovale)
■ Patent Ductus Arteriosus
■ Atrioventricular Septal Defect (Rare, usually a very low ASD)
Obstructive Lesions (acyanotic) include:
■ Pulmonic Stenosis
■ Bicuspid Aortic Stenosis (Discussed in Valvular Disorders unit)
■ Coarctation of the Aorta
■ Hypoplastic Left Heart Syndrome (can sometimes have mild cyanosis
Pathophysiology of Acyanotic anomalies with Left-to-Right Shunts:
○ Oxygenated blood from the left heart (or the aorta) shunts into the right
heart (or the pulmonary artery) through an opening or communication
between the two sides.
○ If the size of the shunt is significant, this left-to-right shunt can increase
pulmonary arterial pressure to the point where symptoms develop.
Pathophysiology of Obstructive Lesions
○ In obstructive acyanotic disorders, blood
flow is obstructed, causing a pressure
gradient across the obstruction.
○ The resulting pressure overload proximal to
the obstruction may cause ventricular
hypertrophy and heart failure.
○ Additionally, the most obvious
manifestation is a heart murmur.
T/F congenital cardiovascular abnormalities will always lead to heart failure
F - some will and some won’t
A ____ is considered the most common type
of congenital heart defect
VSD
_____ are the most common lesion in many
chromosomal abnormalities (like Trisomy 21).
VSDs
Pathophysiology of Ventricular Septal Defect
○ Because of the strength of LV contraction, a
left-to-right shunt occurs with a VSD.
○ This causes, however, increased blood flow to the lungs, increasing pulmonary pressure.
○ The smaller the defect, the greater the
gradient from LV to RV, and the louder the
murmur that is heard.
Eisenmenger Syndrome
○ Defined as the process in which a long-standing left-to-right shunt (caused by a
VSD, ASD, or less commonly a PDA) causes pulmonary hypertension, and
eventually, reversal of the shunt direction.
○ Over time, this increased pressure
causes damage to pulmonary
vasculature, increasing resistance.
○ The increased resistance eventually
reverses the shunt, resulting in a
cyanotic condition. CLUBBING!
Ventricular Septal Defect presentation
○ Clinical presentation of a VSD depends on the size of the defect
○ Small VSDs cause loud, harsh, holosystolic murmurs.
○ Larger shunts may create RV volume and pressure overload and are
more likely to cause Pulmonary Hypertension and Eisenmenger’s.
○ Right ventricular heart failure is a consequence of long-standing VSD,
often accompanied by cyanosis and clubbing (Eisenmenger’s).
Diagnostic Evaluation of Ventricular Septal Defects
○ Echocardiogram is the diagnostic study of choice
○ MRI and CT can often visualize the defect and describe any other
anatomic abnormalities as well.
○ EKG may be normal or may show evidence of ventricular hypertrophy
○ Chest X-ray
○ Cardiac catheterization is usually reserved for those with suspected
pulmonary hypertension and RV overload.
Ventricular Septal Defect treatment
○ Patients with a small VSD have a normal life expectancy, but a small risk
for infective endocarditis (Dental Abx prophylaxis recommended).
○ For large VSDs, heart failure develops early in life and survival beyond 40 years of age is unusual without treatment.
○ Surgical closure is recommended with larger shunts
○ Sometimes, cardiologist may choose medical management with Pulmonary Vasodilator therapy (treatment for Pulm Hypertension).
Atrial Septal Defect (and PFO)
● Atrial Septal Defects account for about 10%
of CHD, and as much as 20-40% of CHD
presenting in adulthood.
● The most common form of ASD (80%) is
persistence of the ostium secundum.
○ Usually arises from an enlarged
Foramen Ovale (PFO)
● ASDs occur about twice as commonly in
females
Atrial Septal Defect (and PFO) pathophysiology
○ Oxygenated blood from the higher-pressure LA shunts into the RA, which functionally increases RV output and pulmonary blood flow.
○ The pressures are less severe in ASD, so Eisenmenger’s is much less common than in VSD (even though shunt reversal can occur in some).
○ In children, the degree of shunting can be quite
large. As the RV compliance worsens from
chronic volume overload, the pressures may
switch, causing a right-to-left shunt.
ASDs predispose individuals to _____ due to RA enlargement,
Atrial Fibrillation
Atrial Septal Defect (and PFO) presentation
○ Patients with a small or moderate ASD or with a PFO are asymptomatic
unless a complication occurs. Like what?
○ With larger ASD shunts, exertional dyspnea or heart failure may develop, most commonly in the fourth decade of life or later
○ A moderately loud systolic ejection murmur can be heard in the 2nd and 3rd interspaces
○ Again, due to the increased RV and Pulmonary Artery volume, there
is also a widely split S2 that does not vary with respirations
