Congenital Heart Defects (acyanotic)

Atrial Septal Defect (ASD)

Associated with fetal etOH syndrome
Ostium primum defect (ASD 1): Associated with Down syndrome & other defects
Ostium secundum defect (ASD 2): MC and usually an isolated defect
If septum doesn't close all the way ➔ minor L ➔ R shunting
- ↑ right sided volume leads to pulmonary HTN, RVH, RAE ➔ atrial arrhythmia
- ↑ risk of paradoxical embolization (thrombi crosses defect and goes into circulation)
  - Can land in brain ➔ cryptogenic stroke, GI ➔ mesenteric ischemia, heart, or extremities

Atrial septum
- One side of the septum - septum primum has a hole (ositum secundum)
  - Septum primum grows down. If it doesn't make it all the way down ➔ ASD 1
    - Defect at lower part of septum ➔ mitral valve problems
- Other side of the septum - septum secundum covers ositum secundum and has a hole (foramen ovale)
  - Together they form a pseudo-valve allowing for blood to flow R ➔ L (only)
- Septum primum and secundum fuse after birth and close off foramen ovale
Patent Foramen Ovale: means the ASD has some kind of tissue (flap) over hole

As an adult (by 40yo) undx pts will have sx from pulmonary congestion/HTN
- Dyspnea, frequent respiratory infxns
Systolic ejection murmur at pulmonic valve
Wide & fixed split S2
- Fixed = doesn't change with respiration
- Mid-diastolic rumble from ↑ flow through tricuspid valve (Relative stenosis)
RAE ➔ arrhythmia, RV heave (left sternal border/subxiphoid)
Platypnea-orthodeoxia (rare): dyspnea and arterial desaturation in upright position that improves when supine

↑ RA volume ➔ ↑ RV volume ➔
- ↑ flow across pulmonic valve ➔ systolic ejection murmur
- Prolonged RV emptying ➔ delayed pulmonic valve closure ➔ split S2
EKG may show Crochetage pattern: notched R-wave peak in inferior leads
- ↓ sensitivity but ↑ specificity for ASD
ASD rarely ➔ Eisenmenger syndrome

TTE good enough for DX but TEE better for sizing and position of defect
MRI if inconclusive echo
Cardiac cath is gold standard for measuring pulmonary to systemic flow ratio (Qp/Qs)

In children: Small 3-6mm ASD without clinically significant right side overload get monitored
- Symptomatic or significant shunt ratio ➔ patch repair after age 2 (in hopes of spontaneous closure)
In adults: Generally want to close in adults with impairment or asx with RA/RV enlargement as long as no pulmonary HTN
- Generally avoid closing when pulmonary HTN is present

Next: COA

Google Sites

Report abuse