·
Often diagnosis in adult
·
Women 3:1 Men
CLINICAL FEATURES
Symptoms
· Asymptomatic for many years
· Dysnoea, cardiac failure and atrial fibrillation are possible
modes of presentation
On CVS examination
· Mid-systolic ejection in pulmonary area
· Loud P2 , wide fixed splitting of S2
· Diastolic flow murmur
PATHOPHYSIOLOGY
Communicating at level atria (interatrial
septum) allows LEFT-to-RIGHT shunting of the blood. Because the pulmonary
vascular resistance is low and the right ventricle easily distended, there is a
considerable increase in right heart output. Murmur is produce by increase flow
across pulmonary valve and increase stroke volume.
Above the age 30 years there may be
an increase in pulmonary vascular resistance which can lead to pulmonary HPT.
AF is common at this stage.
TYPES of ASD
1)Foramen secundum defect
Commonest
- Excessive resorption of septum primum or inadequate
development of septum secundum
2)Foramen primum defect:
- Septum primum fails to fuse with septum intermedium
(endocardial cushion)
3)Sinus venosus defect:
- Incomplete absorption of the sinus venosus into right
atrium
4)Common atrium
- The septum primum and secundum fail to develop
- The whole interatrial septum is absent.
INVESTIGATIONS
1. 1. Chest X-ray
Prominent pulmonary arteryPulmonary plethora [fullness]
Right ventricular hyperthrophy
2 2. ECG
Usually shows
some degree of RBBB due to right ventricle hyperthrophy
Right axis
deviation
3 3. Enchocardiogram:
shows RVH and pulmonary arterial dilatation
TREATMENT
Surgical repair of the large defect before the age of 10
years or as soon as possible if first diagnosed in adulthood.
REFERENCES
1. Kumar P, Clark M, editors. Kumar and Clark Clinical Medicine, 7th ed.
2. Mohammad Inam Danish, editor. "Medical Diagnosis and Management"
