Relationship Between Two Arrhythmias: Sinus Node Dysfunction and Atrial Fibrillation

We reviewed recent advancements in the relationship between sinus node dysfunction (SND) and atrial fibrillation (AF) and propose some underlying mechanisms in regard to ion and molecular aspects. The amount of clinical and animal experiments have proven the structural and electrophysiological remodeling of sinoatrial node (SAN) and atrium may be related significantly between SND and AF. Atrial remodeling was often related to RAS activation. RAS inhibitors and statin, which resist in atrial fibrosis, may be novel strategies to prevent or treat both SND and AF. Besides, funny current (If) and Ca2+ clock mainly contributing to the SAN automaticity may be another link between SND and AF. Gap junctions such as Cx40, Cx43 and Cx45 were proven to participate in both automaticity and conductivity of electrical impulses in SAN and atrial tissue, which was accepted as another link between SND and AF. Common genetic mutations such as the emerin gene, SCN5A gene and HCN4 gene mutation were also the mechanism for the correlation between SND and AF.