Atrial septal defect (ASD) is the second most
common congenital heart disease in adults.
Approximately 10% of all congenital heart lesions.
Isolated ASD results from abnormal development
of the septa that partition the common atrium of
the developing heart into right and left chambers.
70% of ASDs are of the ostium secundum variety.
The incidence of ASD is approximately 3 per
10,000 live births.
The interatrial septum forms during the
first and second months of fetal
Stage I is the formation of the septum
The septum primum walls off a crescent-
shaped portion of the hole between the
right and left atria.
Foramen primum (also called the ostium
primum) stays open
The remaining part of the opening
between the right and left atria is closed
by the septum secundum.
The 2 tissue layers overlap like a flap,
allowing blood flow to continue during
Changes in circulation at birth, closes
the flap permanently.
Anatomy and Physiology
Extends from cavo-
atrial junction with
superior and inferior
Ends near the atrio-
near the tricuspid
Next most common type
Located in the lower
portion of the atrial
Will often have a mitral
valve defect associated
with it called a mitral valve
A mitral valve cleft is a slit-
like or elongated hole
usually involves the
Least common type of ASD
Located in the upper portion of
the atrial septum.
Association with an abnormal
pulmonary vein connection
Four pulmonary veins, two from
the right lung and two from the
left lung, normally return red
blood to the left atrium.
Usually with a sinus venosus
ASD, a pulmonary vein from the
right lung will be abnormally
connected to the right atrium
instead of the left atrium.
This is called an anomalous
Remnant of fetal
Behaves like flap
WHEN TO SUSPECT IN 2D
RIGHT VENTRICULAR DILATION
ABNORMAL MOTION OF IVS- brisk anterior
movement in early systole or flattened
movement throughout diastole
? IAS DROP OUT IN APICAL 4C VIEW
RELATIVE ATRIAL INDEX
RELATIVE ATRIAL INDEX
Standard apical 4C views- right atrial area divided by
left atrial area
Cutoff value of >0.92 predicted patients with ASDs
v/s matched controls with 99.1% sensitivity and 90.5%
After closure, significant atrial remodeling occurred
immediately, with a reduction in the mean RAI at day
1 to 0.93 ± 0.16 (P < .0001) and complete
normalization at early follow-up to 0.81 ± 0.12.
The Relative Atrial Index (RAI)—A Novel, Simple,
Reliable, and Robust Transthoracic Echocardiographic
Indicator of Atrial Defects
Natalie A Kelly -Journal of the American Society of
The role of echocardiography
Indication – RV – volume load (TTE)
Screening for feasibility of intervention
Native ASD size – septal size on LV aspect
Number of ASD`s
Position of ASD – rims (aorta, AV-valve,
SVC/IVC, right pulmonary veins)
Monitoring of the procedure
Accurate measurement of the defect size plays a key
role in closing ASD using a percutaneous occluder
It is possible to determine the size of the defect by
transesophageal echocardiography (TEE), which is a
In the literature, it has been emphasized that TEE is a
gold standard in transcatheter closure of ASD and
thus should be used in analyzing septal defect and
rims during the process.
Therefore, using echocardiographic parameters
affecting success of closure may prevent possible
complications in percutaneous closure of ASDs.
In terms of success, there is no definite ASD size or
predictor as the size of ASD differs from 1 patient to
Determining other predictors along with the measured
ASD size and evaluating the closure together with
such predictors would increase the chance of
Conventionally, the rims of a secundum ASD are
atrioventricular (AV) valve (mitral or
superior venacaval (SVC or superoposterior),
inferior venacaval (IVC or inferoposterior), and
posterior (from the posterior free wall of the atria,
coronary sinus rim).
By conventional definition, a margin 5 mm is considered to be adequate.
Podnar et al. defined 10 morphological variations of defects,
the most common type being the defect with deficient aortic rim (42.1%).
The other variants included
central defects (24.2%),
deficient inferoposterior rim (12.1%),
perforated aneurysm of the septum (7.9%),
multiple defects (7.3%),
combined deficiency of mitral and aortic rims (4.1%),
Deficient SVC rim (1%), and
deficient coronary sinus rim (1%).
SUB COSTAL 4C VIEW
To go for the subcostal 4C – Keeps the atrial
septum perpendicular to the ultrasound
Distinguishes OS , OP & SV ASDs
Measurements of the septum can be taken
Anomalous drainage of pulmonary veins
Atrial septal aneurysm
TTE -views for ASD
PSAX- IAS separates Rt &Lt atrium and runs
posteriorly from NCC of aortic valve.
Not seen in entirety as a result of drop out artefact
APICAL 4C- Posterior aspect of Interatrial septum is
clearly delineated in this view but drop out artefact is
seen in region of fossa ovalis.
Pulmonary venous drainage- 3 veins draining to LA
APICAL 5C VIEW- Anterior aspect of interatrial
IAS AGAINST NCC
APICAL 4C VIEW
SHOWING THE IAS AND 3
VEINS DRAINING TO LA, RT
LOWER PULMONARY VEIN
IS USUALLY NOT SEEN
SUB COSTAL 4C VIEW- Useful in patients with COPD and
Viewed with breath held in inspiration- index marker in 3o`
No IAS drop outs
SUB COSTAL SHORT AXIS- Index marker at 12o`clock
position and sweeping the transducer from midline to Rt side
Other important views
To visualise SVC- Suprasternal short axis –index
marker in 4 o`clock position
L-SVC is seen from left supraclvicular fossa or
suprasternal short axis
Suprasternal short axis to visualise the the pulmonary
veins draining into left atrium
Cleft mitral valve in AVCD in 12o`clock position in
En face view in 2D
First the apical 4c view was taken.
The image index marker was at approximately
kept at 1 o'clock.
Keeping the atrial septum and ASD in the region
of interest, the transducer was rotated
counterclockwise approximately 45° to 60°.
Xinseng et al Journal of the American Society of Echocardiography Volume 23, Issue 7 , Pages 714-
721, July 2010
Ostium primum ASD
Defect in lower part of IAS
Associated sometimes with inlet VSD
Cleft mitral valve
AV Valve regurgitation
Partial attachment of mitral valve to IVS
Apical four chamber view demonstrating
a primum atrial septal defect
Colour Doppler flow image from same view
illustrating left-to-right shunt across the primum
atrial septal defect
ATRIAL SEPTAL ANEURYSM
A- PROTRUSION OF
ANEURYSM ATLEAST 15MM
OF PLANE OF IAS
IAS SHOWING 15MM OF
B- BASE WIDTH≥ 15MM
Shows the direction of the shunt
Caveat- False Positive results due to improper gain and caval
flow streaming near septum can be misdiagnosed as ASD.
PULSED DOPPLER- demonstrates the flow from L to R in
mid systole to mid diastole with second phase in atrial
systole. Some R to L shunting occurs in early systole
QUANTIFICATION OF SHUNT – Qp /Qs
• ARROW SHOWS NEGATIVE
• DIRECT EVIDENCE OF SHUNT-
CONTRAST BLOOD IN RA
•Extent of shunting tend to focus on
numbers of bubbles seen in a single
still frame in the left atrium.
Shunt grading incorporates :
Grade 1: 5 bubbles;
Grade 2: 5 to 25 bubbles;
Grade 3: >25 bubbles;
Grade 4: Opacification of chamber
Echocardiographic Evaluation of Patent Foramen Ovale Prior to Device
Bushra et al JACC 2010 VOL. 3, NO. 7, 2010
RIMS OF ASD
Aortic - Superoanterior
Atrioventricular (AV) valve -mitral or inferoanterior
Superior Vena Caval SVC – Superoposterior
Inferior venacaval (IVC or Inferoposterior) Posterior
(from the posterior free wall of the atria).
The transesophageal echocardiography (TEE) probe is at the
mid-lower esophageal level.
The posterior and the mitral rims are best evaluated in
Rotating the probe to 30° to 40° towards the left will best
profile the aortic (Ao) rim.
The margins are evaluated by carefully moving the probe in
and out and obtaining sections at various levels.
At the level of the
atrioventricular valves (C), the septum forms once again. This
suggests that the ASD is likely to have adequate margins for
In the highest plane (A), the superior venacaval (SVC)-right
atrial junction and the ascending (Asc) aorta are seen; the
atrial septum is visualized as intact.
At the mid-level (B), the septum breaks and the
margins(posterior and anterior) of the atrial septal
defects (ASD) (arrows) are clearly seen.
At the level of the atrioventricular valves (C), the septum
forms once again.
This suggests that the ASD is likely to have adequate
margins for catheter closure.
TEE at 90° to Evaluate the SVC
and IVC Rims
AORTIC RIM IS SEEN
TEE 45 DEGREES
This view is best for evaluating the SVC and IVC
The margins are evaluated by rotating the probe
while keeping it at more or less the same level.
Here the defect is seen with the probe rotated
leftward (B, margins of the ASD shown by the
arrows), while septum is seen to form when the
probe is rotated to the right (A).
The 45°-view is helpful in assessing the posterior
and the aortic rims and often helps to determine
the maximum size of the defect.
Echocardiography plays a critical role for patient
selection, guidance, and post-deployment evaluation
for transcatheter closure of ASDs.
Understanding the echoanatomic corelation by
transesophageal echocardiography is perhaps the
most essential requisite to ensure a successful
3D echocardiography and ICE (intra-cardiac echo) are
likely to further this understanding in the future
especially in difficult cases like multiple defects and
defects with deficient margins.
Natural history of ASD
Natural history of ASD diagnosed in childhood is that the ASD
diameter when untreated increases in 65% of cases, and
30% will have more than a 50% increase in diameter.
Only 4% of ASDs close spontaneously .
A patient with isolated secundum ASD is often asymptomatic
until the third and fourth decade of life.
Typical symptoms that ensue include decreased exercise
capacity, fatigue, syncope and palpitations.
Patients with significant shunting may develop right
ventricular failure, atrial tachycardia, pulmonary hypertension
and embolic events all of which can lead to significant
morbidity and potential mortality.
The age at which a patient becomes symptomatic is highly variable
and does not correlate well with shunt size .
The pressure gradient between the two atria and the amount of
shunt flow depend upon both the size of the defect, and the
compliance of the right and left sides of the heart.
Left untreated over time, even small ASDs can develop increased
left-toright shunting due to progressive increase in left ventricular
(LV) diastolic pressure with aging, which causes increased left atrial
In patients who develop pulmonary hypertension (PHTN) from their
ASD, approximately 10% will progress to Eisenmenger’s syndrome.
Due to the chronic nature of the disease and patient compensation
over time many patients remain unaware of their decreased
exercise capacity and only realize their symptom improvement post
Special tee views for
No Infero posterior rim with probe in normal position
K.S. Remadevi, MD, FNB, Edwin Francis, DM, and Raman Krishna
Kumar, DM, FACC . Catheterization and Cardiovascular Interventions
Retroflexed probe in the stomach and bought towards the esophagus and viewed
In the 70-90o view
Notas do Editor
OSTIUM SECUNDUM- MIDDLE OF ATRIAL SEPTUM
OSTIUM PRIMUM – LOWER PART OF ATRIAL SEPTUM