IL6 and atrial fibrillation: Serval clinical and animal studies have reported that atrial tissues in AF can be infiltrated with neutrophils and lymphocytes, in contrast to those in the sinus rhythm such as TNF-α and IL-6 (Frustaci et al., 1997; Patel et al., 2010; Guo et al., 2012; Smit et al., 2012; Jacob et al., 2014).