IL6 and atrial fibrillation: The ability of cardiomyocytes, particularly cardiac fibroblasts, to produce IL-6 has already been demonstrated.24 In previous studies, higher levels of inflammatory markers, including IL-6, have been shown in blood samples from patients during AF in comparison to those with sinus rhythm.25 In line with this, IL-6 in our study appeared in a higher concentration in peripheral venous samples from patients with PeAF than PAF, which could be explained by the previously suggested mechanism by which AF promotes inflammation.