Atrial septal defect

Atrial septal defect

Atrial septal defect

Asd is an abnormal communication between two atria .  Congenital heart disease wth lt to rt shunt
  *TYPES
1. Ostium secondum type - located at fossa ovalis.Ten times more common
2. Ostium primum type - inf. to fossa ovalis
   *HEMODYNAMICS
-There is leak of oxygenated blood from lt to rt atrium
- pressure diff. betwn 2 atria is small hence shunt is silent on auscultation
-rt. atrium enlarges in size to accomodate extra volume of blood from left atrium
-large volume of blood passes through normal sized tricuspid valve resulting in delayed diastolic murmur audible at lower lt. sternal border.
-pulm. ejection murmur. Pulmn. valve closes late resulting in delayed P2 .Second sound is widely split & fixed P2 is also accentuated
-cardiac apex formed by rt. ventricle



-lung fields are plethoric
    *CLINICAL Features
-most asyptomatic
-mild effort intolerance
-frequent chest infectios
- Physical examination
    1 parasternal impulse
   2 cardiac enlargement
   3 first sound - normal or may be enlarged
   4 second sound - widely split & fixed wth P2 accentuated
   5 ejection systolic murmur at 2nd & 3rd lt interspace
   6 shunt murmur abs
   7 flow murmur (a) tricuspid - delayed diastolic (b) pulmonary   -  ejection systolic

   *INVESTIGATIONS
    1 ECG
  1 ostium secundum asd  - rt. axis deviation & rt. Ventricular hypertrophy
  2 ostium primum asd - lt. Axis deviation beyond  -30 degree
    2 CXR
  mild to moderate cardiomegaly ,rt. Atrial & yentricular enlargement ,prominent main pulmonary artery ,small aortic shadow & plethoric lung fields
    3 ECHOCARDIOGRAM
    increased size of rt. ventricle
    *COMPLICATIONS
  1. Pulmn. arterial Htn
     *Rx
 -size of lt. to rt. shunt directly proportional to intensity of the two murmur & heart size
- Rx chest infection
-prophylaxis for IE
-definitive cure by operation.  Most surgeon prefers heart lung bypass. Ideal age for operations 2-5yrs.