@entity2917 ( @entity2917 ) requiring an accessory atrioventricular pathway (AP) is the most common type of @entity943 in the perinatal period. The etiology of these @entity943 is not fully understood as well as their capability to dissipate spontaneously in the first year of life. Temporary presence of APs during annulus fibrosus development might cause this specific type of @entity943 . To study the presence of APs, electrophysiological recordings of ventricular activation patterns and immunohistochemical analyses with antibodies specifically against @entity955 ( @entity13470 ), Periostin, @entity39756 , and @entity16899 were performed in embryonic @entity19 hearts ranging from 11.5 to 18.5 days post-conception (dpc). The electrophysiological recordings revealed the presence of functional APs in early (13.5-15.5 dpc) and late (16.5-18.5 dpc) postseptated stages of @entity19 heart development. These APs stained positive for @entity13470 and @entity39756 and negative for Periostin and @entity16899 . Longitudinal analyses showed that APs gradually decreased in number (p = 0.003) and size (p = 0.035) at subsequent developmental stages (13.5-18.5 dpc). Expression of periostin was observed in the developing annulus fibrosus, adjacent to APs and other locations where formation of fibrous tissue is essential. We conclude that functional APs are present during normal @entity19 heart development. These APs can serve as transient substrate for AVRTs in the perinatal period of development.

Accessory atrioventricular myocardial pathways in XXXX heart development: substrate for supraventricular tachycardias.

@entity16899 :: ('14609(Tax:10090)', 'Gene') :: ['Connexin-43'] @entity39756 :: ('18091(Tax:10090)', 'Gene') :: ['Nkx2.5'] @entity2917 :: ('MESH:D013611', 'Disease') :: ['AVRT', 'Atrioventricular reentry tachycardia'] @entity19 :: ('10090', 'Species') :: ['mouse'] @entity13470 :: ('17898(Tax:10090)', 'Gene') :: ['MLC-2a'] @entity955 :: ('MESH:D001281', 'Disease') :: ['atrial myosin light chain 2'] @entity943 :: ('MESH:D001145', 'Disease') :: ['arrhythmias', 'arrhythmia']
@entity19 :: (10090,Species) :: ['mouse']
