The research of molecular and ionic mechanisms in vagally mediated atrial fibrillation in canine

Background The reentrant mechanism of vagally mediated AF is not clearly elucidated. Methods and results After vagal stimulation, thirty dogs were divided AF group (AF could be induced) and control group (AF could not be induced). Western blot and patch clamp were used to determine M2 receptor and IK,ACh in left atrial appendage (LAA), right atrial appendage (RAA), left atrium (LA), right atrium (RA), pulmonary veins (PVs) and superior vena cava (SVC). In control group, the densities of M2 receptor and IK,ACh in LAA, RAA and LA were higher than that in RA, PVs and SVC. However, there was no significant difference in LAA, RAA and LA. In AF group, the densities of M2 receptor and IK,ACh in LAA, RAA and LA were higher than that in RA, PVs and SVC. Furthermore, the densities of the M2 and IK,ACh in LAA and RAA were higher than that in LA. Conclusions Atrial appendage perhaps play an important role in initiation of cholinergic AF. However, PVs and SVC less often play an important role in vagotonic paroxysmal AF.