Atrial Septal Defect

Arvin Raj061303507Group B2

• ASD is an acyanotic CHD characterized by defect in the interatrial septum

• Causing a left to right flow between the atria

• Severity depends on : - size of defect - size of shunt - associated anomalies• Resulting in spectrum from : - asymptomatic to - right sided overload, pulm. Art. HTN, and

even atrial arrhythmias

• ASD represents 10% of all CHD ( emed )

• 3 common types

- Ostium secundum ( 75% )

- Ostium Primum ( 15 – 20% )

- Sinus venosus ( 5 – 10% )

• Male : female = 1:2

• Most infant and children are

asymptomatic, but this again depends on

severity of defect

• Symptoms are more prevalent as patient

ages, usually around age of 40

• Magnitude of L – R shunt depends on :

- Defect size

- Compliance of ventricles

- Relative resistance in both pulmonary

and

systemic circulation

• Shunting occurs during late vent systole

and early diastole

• The volume overload is usually well

tolerated in children

• Even though the pulmonary flow may

be more than twice

• However if left untreated… reversal

of shunt can eventually occur at a

later age.

Presentation

Symptoms• Often asymptomatic• Easy fatigability• Recurrent chest infection• Exertional dyspnoea• Palpitations related to arryhthmias

Signs

• Wide fixed split of S2 ( mostly seen in large

defects )

• S1 may be split with the second component being

increased in intensity due to delayed tricuspid

closure and forceful contraction of right ventricle

• ESM - increase right sided flow ( 2nd IC space at

upper left sternal border )

• Large defects may have rumbling MDM at lower

left sternal border ( increase flow across tricuspid)

CXR

Enlarged pulmonary arteries and increased vascular markings

Enlarged right atrium along with dilatation of right ventricle

ECG

Enlarged ‘p’ wave indicating Right atrial hypertrophy

rSR’ seen and tall R waveIndicating RBBB and RVH

Also note that the aVF is predominantly upwards as compared to Lead I indicating Right Axis Deviation

LAD with rSR’ in V1 is suggestive of Ostium primum defect

Echocardiography

• Main diagnostic investigation

• Transthoracic 2D echocardiography especially

subcostal view is very helpful

• Transesophageal Echo used for sinus venosus defect

• Doppler echo is used to demonstrate the flow across

the septum

MRI

• Can be use to identify size and location of

defect

• A major advantage of MRI is the ability to

quantify right ventricular size, volume, and

function along with the ability to identify

the systemic and pulmonary venous

return.

Treatment

• No medical treatment

• Surgical

- Median sternotomy with direct closure of

small to moderate defect

- Larger defects closed with autologous

pericardium or syntethic patches like

polyester polymer

( Dacron )or polytetrafluoroethylene ( PTFE )

• Minimally invasive techniques with

hemisternotomy and limited thoracotomy

is to improve cosmetic outcome

• Percutaneous Transcatheter Closure

- via femoral vein

- success is as good as 96% in good hands