Dr.S.Venkatesan MD

Spontaneous closure of VSD is  a well recognised  phenomenon, than ASD  though both happen in equal frequency.The simple reason being VSD is a noisy disease , ironically the smaller the size of VSD  more noisy it is . Hence  it is rarely  missed  while ASD is largely silent in children. For this reason  it is  possible ASD may be the most common congenital disease .

Natural history of ASD(OS) closure

• ASDs of size 3-4 mm 100 % will close by 3  years
• Bulk of the ASD < 8  mm close spontaneously by 5 years.
• ASD> 10mm is unlikely to close

Factors that determine spontaneous closure

• Apart from size and location
• Closure  is accelerated by remnant of flap of foramen  ovale
• Fenestrations and  Septal  aneurysms also  favor spontaneous closure.
• Margins  of the defect if rough  triggers fibrotic reactions

Why SVC and primum defect do not close easily ?

Plane of ASD  secundum is single and  bridging of tissue is possible .

Sinus venous and  primum defects exhibit  holes which run in multiple planes hence approximation not possible . They also do not  have a valve mechanism.

Un-natural history of ASD

In the current era, one more  force interferes  with spontaneous closure of ASD . It  comes from the  hyper trained aggressive Interventional cardiologists who compete with the nature and easily prevail over it !

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