IL4 and atrial fibrillation: The percentage of IL‐4R, IL‐4, and IL‐10 immunopositivity was quantified in human NP/AF and CEP tissue samples (Table 1) obtaining 44.8% IL‐4R, 10.8% IL‐4, 30.6% IL‐10R in NP/AF, 58.9% IL‐4R, 14.3% IL‐4, and 27.5% IL‐10R in CEP regions (Figure 1A–C).