AV nodal tissue is a not compact structure as we would be believe . But it is a fact , AV node do attempt to compact after birth.
It is never complete.
All specialised cells should coalesce to form the compact zone .This fails to happen in many . Failure of AV nodal compaction results in islands of slow conducting cells in around AV node . Some of them can mutate , and acquire fast conducting properties as well . (Accessory pathway )
This failure of AV nodal compaction is termed as persistent fetal dispersion of AV node .
In the his bundle same phenomenon is called as his bundle de-fragmentation .These abnormalities are noted in pathological specimens of Pokkuri sudden death in Asians .
Unexplained sudden deaths and instant bradycardias and complete heart blocks are related to these dispersion of AV nodal cells downstream . This also explains some of patients with infra hisian escape show junctional characteristics.
Many cardiac pathologists have observed this . Still there is a missing link .
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