A site for medical students - Practical,Theory,Osce Notes

What is the Hemodynamics in ASD ?

The essential hemodynamic feature of ASD is right ventricular volume overload.
When there is RV volume overload it produces the following effect.
  • Right ventricle compress on the let ventricle producing reverse Bernheim effect on the interventricular septum.
  • Right ventricle compress on the coronary arteries.
What are the main fectors that determine the shunt in ASD
Shunt in ASD is determined by
  • Size of septal defect
  • Relative distensibility of the left and right ventricle.
  • Pulmonary as well as systemic vascular resistance.
Large septal defect produce the following effects
  • Cardiomegaly 
  • Load ejection systolic murmur with thrill in the pulmonary area
  • Tricuspid midiastolic murmur
These three factors are used to access the size of ASD
Describe about ASP with bidirectional shunt
This is ASD with shunt occurring in either direction, based on pulmonary and systemic vascular resistance.