Congenital heart dz Flashcards
What are the major causes of congenital heart disease?
Sporadic genetic abnormalities
Ex: Turner syndrome (issues w/ blood vessels), & trisomies 13, 18, 21
What is the single most common genetic cause of congenital heart disease?
Trisomy 21 (Down’s)
40% of Down’s pts have at least 1 heart defect
In Down’s, where is the heart defect usually derived from?
The second heart field (arterioventricular septae)
Most commonly defects of the endocardial cushion:
- VSDs
- ASDs
- ostium primum
- AV valve malformations
What genes are associated with congenital heart defects?
Notch pathway associated with variety of congenital heart defects:
- NOTCH1 (bicuspid aortic valve)
- JAG1 & NOTCH2 (tetralogy of Fallot)
Fibrillin mutations underlie Marfan syndrome = associated with valvular defects & aortic aneurysms
Name some congenital heart diseases. Include the most frequent first.
Ventricular septal defects (VSD)
Atrial septal defects (ASD)
Patent Ductus Arteriosus (PDA)
Left-to-right shunts
Right-to-left shunts
Obstructive lesions
What is the most common congenital heart dz?
Left-to-right shunts :
- ASD
- VSD (most common)
- PDA
During ASD, VSD, & PDA, what happens to pulmonary volume and pressure?
ASD increases only RV & pulm outflow volumes
VSD & PDA increase pulm blood flow & pressure
What is a secundum ASD?
90% of all ASDs
Center of atrial septum; may be multiple or fenestrated
What is a primum anomalie?
5% of all ASDs
Adjacent to AV valves; often assoc w/ AV valve abnormalities &/or VSD
What are sinus venosa defects?
5% of all ASDs
Near entrance of SVD; can be assoc w/ anamalous pulmonary venous return to the R atrium
What is the result of left-to-right shunts? How can it be resolved?
Cause volume overload on right side; may lead to:
- Pulmonary HTN
- Right heart failure
- Paradoxical embolism (where it travels to brain & causes stroke)
May be closed surgically with normal survival
Describe what happens with a patent foramen ovate (PFO). Include Sx.
80% closes permanently by 2 yo
Remaining 20% - flap can open if there is increase in right side pressure
Even temporary increase in pressure produces brief periods of R-L shunting causing:
- Pulmonary HTN
- Bowel movement
- Coughing
- Sneezing
Can lead to a paradoxical embolus
Describe the types of VSDs
90% = membranous VSD = in membranous interventricular septum
Infundibular VSD = below pulmonary value, or within muscular septum
How do VSD effects differ from pt to Pt?
Effects depend on size, & presence of other heart defects
Those that manifest w/ Sx as children, often assoc w/ other cardiac anamolies
Many (50%) small VSDs close spontaneously
Large VSDs may cause significant shunting. What does this lead to?
Right ventricular hypertrophy
Pulmonary HTN
Unclosed large VSD can ultimately result in shunt reversal, leading to cyanosis & death
When may a patent ductus arteriosus (PDA) fail to close?
Infants are hypoxic, and/or have defects assoc w/ increased pulmonary vascular pressure (VSD)
Describe how a PDA appears clinically.
Produces a harsh, machinery-like murmur
- usually asymptomatic at birth
- initially left-to-right, so no cyanosis
How is the effect of a PDA determined?
Shunt’s diameter
Large shunts can increase pulmonary prisolated PDA should be closed as early as possible
Isolated PDA should be closed as early as possible
When can a PDA be beneficial? How can it be preserved?
Preservation of patency can be lifesaving in infants w/ obstruction of pulmonary or systemic outflow
Can be preserved w/ prostaglandin E
What is the main Sx you see with right-to-left Shunts? What is the most common right-to-left shunt? What are some others?
Sx: cyanosis early in postnatal life (cyanotic congenital heart dz)
Tetralogy of Fallot (TOF) = most common
Transposition of great arteries
persistent truncus arteriosus
Tricuspid atresia
Total anomalous pulmonary venous connection
What are the 4 cardinal features of Tetralogy of Fallot?
VSD
Obstruction of RV outflow tract
Aorta overrides the VSD
RV hypertrophy
How does tetralogy of Fallot appear on imaging?
Heart is enlarged a “boot-shaped” b/c of the right ventricular hypertrophy
What does clinical severity of Tetralogy of Fallot depend on?
Degree of subpulmonary stenosis
Mild stenosis = L-to-R shunt
Classic TOF = R-L shunt with cyanosis
Most infants cyanotic form birth, or soon thereafter
Describe the transpostion of the great vessels (TGA). What other conditions do you see with this? What does survival look like?
Results in 2 separate systemic and pulmonary circulations
Incompatible with life after birth unless a shunt is present for mixing of blood b/w 2 circulations
- approx 1/3 have VSD
- 2/3 have patent foramen ovale or PDA
- Right ventricle becomes hypertrophic (supports systemic circulation) and the left ventricle atrophies
Without surgery, pts will die within a few months
