Immune remodeling involving macrophage recruitment and activation in atrial fibrillation is characterized by the release of proinflammatory factors, including tumor necrosis factor-α (TNF-α), macrophage migration inhibitory factor (MIF), interleukin-1-beta (IL-1β), IL-6, and galectin-3, which can induce atrial electrical remodeling [34]. Here, MIF is linked to atrial fibrillation.