3. DEFINITION
• An atrial septal
defect is an
opening in the
atrial septum, or
dividing wall
between the two
upper chambers
of the heart
known as the
right and left
atria..
5. EMBRYOLOGY
• The heart is forming during the
first 8 weeks of fetal
development.. Atrial septal
defects occur when the
partitioning process does not
occur completely, leaving an
opening in the atrial septum.
6. HEMODYNAMICS
• LARGE VOL OF
BLOOD FROM
RT.ATRIUM
PASSES THRU
NORMAL
TRICUSPID
VALVE &
PULMONARY
VALVE
• DELAYED
DIASTOLIC
MURMUR(LOW
LT STERNAL
BORDER)
• RT.VENTRICLE
ENLARGES
• PULMONARY
EJECTION
MURMUR