Moreover, FGF and GM‐CSF levels were significantly increased in AF when compared with healthy fat as was the level of chemokines involved in macrophage recruitment (CCL2, CCL3, CCL4) (p = 0.015, 0.019, 0.001, 0.005 and 0.001, respectively; Figure 3). Here, CCL4 is linked to atrial fibrillation.