ASD/TOF Flashcards
What are the most important clinically important examples of L to R shunts?
- Atrial septal defect (ASD)
- Ventricular septal defect (VSD)
- Atrioventricular Septal Defect (AV canal)
- Patent ductus arteriosus (PDA)
What is the most common form of congenital heart dz seen in adults?
ASD
What is ASD?
• Abnormal, fixed opening in the atrial septum due to incomplete tissue formation. Usually asymptomatic until adulthood.
What can ASD be confused with?
• PFO (patent foramen ovale) – failure to close foramen ovale.
What does ASD affect?
• Increase RV and pulmonary outflow volumes
What are the 3 major types of ASD?
- Secundum ASD – at the Fossa Ovalis (most common); OS ASD
- Primum ASD – lower in position and is a form of ASVD, can be associated with cleft mitral valve. OP ASD
- Sinus Venosus ASD – high in the atrial septum, associated w/ partial anomalous venous return (least common) SV ASD
What are the clinical signs and symptoms for ASD?
- Rarely, pts present with signs of CHF or other cardiovascular symptoms
- Most are asymptomatic, easy fatigue, mild growth failure
- Cyanosis does NOT occur unless pulmonary htn is present.
What are PE findings of ASD?
Hyperactive precordium
RV heave
What causes the systolic and diastolic murmurs of ASD?
• Systolic murmur
o Caused by increased flow across the pulmonary valve NOT the ASD
• Diastolic murmur is caused by increased flow across the tricuspid valve.
What are the tx options for secundum ASD?
• Surgical or catheterization laboratory closure
When is surgical intevention performed electively for ASD?
- Between ages 2 and 5 yrs to avoid late complications
* Done earlier in children with CHF or significant pulmonary htn.
When is it too late for surgical intervention with ASD?
• Once pulmonary htn with shunt reversal occurs.
What are the dzs that cause early cyanosis?
- Tetralogy of Fallot
- Transposition of great arteries
- Persistent truncus arteriosus
- Tricuspid atresia
- Total anomalous pulmonary venous connection
what are the 4 cardinal features of TOF?
- Narrowing of pulmonary valve
- Displacement of aorta over ventricular septal defect
- Thickening of RV
- Ventricular septal defect – opening between the L and R ventricles
What are the key sxs of TOF?
Cyanosis “Tet spells”: cyanosis after feeding, bowel movement, upon awakening
SOB, tachypnea, respiratory distress (crying baby)
What is the characteristic heart murmur for TOF?
harsh systolic ejection murmur @LSB
What is the CXR finding of TOF?
BOOT SHAPED HEART
What is the compensatory mechanism in pts with TOF?
squatting or knee to chest position in order to increase PVR and thus decreases the magnitude of the R to L shunt across the VSD
What would EKG of TOF show
RVH
What is the characteristic murmur for ASD?
- Fixed widely split S2
- 2-3/6systolic ejection murmur @ L sternal border
- Mid-diastolic murmur heard over LLSB
what kind of shunt is ASD?
L to R shunt
what technique can be used as a screening tool for ASD?
Valsalva maneuver
What happens when ASD pts do valsalva maneuver?
results in increased intrathoracic blood volume, allowing adequate cardiac output to continue despite temporary obstruction of venous return
What is valsalva maneuver?
forceful “exhalation” with mouth closed (nose pinched).
