Brundel et al. [22] investigated the changes in the expression of potassium channel in AF patients, and results showed the mRNA and protein expression of potassium channel in persistent AF patients had a reducing trend, while only the protein expression of potassium channel reduced in the paroxysmal AF patients which suggests the presence of post-transcriptional regulation. The gene discussed is KCNA3; the disease is atrial fibrillation.