TTN and atrial fibrillation: In the domain of electrical remodeling, previous studies have shown that mutations or functional abnormalities in ion channel genes are closely linked to AF, including sodium channel genes (SCN5A), potassium channel genes (KCNQ1, KCNH2, KCNE1, KCNE2), calcium channel genes, hyperpolarization-activated cyclic nucleotide-gated channel genes (HCN), sodium–calcium exchanger genes (NCX1), and the titin gene (TTN) (24–29).