Moreover, we have found a significant increase in LA (p-value = 0.001) and peripheral vein (p-value = 0.017) relaxin-2 plasma levels of AF patients with sinus rhythm compared to AF rhythm (Supplementary Fig. S1 online); together with a significant correlation between cardiac and/or peripheral relaxin-2 plasma levels with Gal-3, DEFA3 and IL-6 in AF patients with sinus rhythm, while these correlations were absent in AF patients with AF rhythm (Supplementary Table S9 online). Here, RLN2 is linked to atrial fibrillation.