adenosine

Adenosine induced atrial fibrillation

Adenosine may initiate AF through 3 possible means:

sympathoexcitatory effects
- baroreflex activation
- chemoreceptor stimulation
shortening the wavelength of atrial activation → potentiating AF
- adenosine shorten atrial action potential duration & refractoriness
- little effect on atrial conduction velocity
- by activation of inward rectifying K+ current IKAdo
direct stimulatory effects on pulmonary vein tissue
- adenosine hyperpolarise dormant pulmonary vein myocytes
- ↑ excitability
- trigger pulmonary vein ectopy

Adenosine and acetylcholine’s cellular electrophysiological effects are mediated by an identical signal transduction cascade. Each ligand binds to its specific G protein–coupled receptor (adenosine A1 and muscarinic M2, respectively) and activates the heterotrimeric protein Gi/o, which then activates the inward rectifying K+ current, IKAdo,ACh. Therefore, adenosine and acetylcholine’s direct electrophysiological effects are one and the same. Because adenosine can trigger AF through its effects within the pulmonary vein, the same is likely true for vagal activation.

References

Adenosine-Induced Atrial Fibrillation Insights Into Mechanism