MAPK14 and atrial fibrillation: The p38 MAP kinase α and β isoforms (p38α and p38β) phosphorylation levels were examined in the atrial tissues of four groups, and the results showed that p‐p38α and p‐p38β levels were increased in the AF‐control and AF‐AdNull groups, and this increase was reduced in the AF‐Adc‐Ski group (Figure S2A‐C).