CHRM3 and cardiac arrhythmia: Since the CAST trial in 1989, more and more people realized that single ion channels cannot be effective in the treatment of arrhythmia, the proteins, the genes, and the ion channels in combination would be a new direction for the treatment of cardiac arrhythmias, and more and more genes and proteins related antiarrhythmias were found, including M3 muscarinic acetylcholine receptor (M3-mAChR), the connexin 43 (Cx43), miR-1, miR-133, miR-590, and the calcium/calmodulin-dependent protein kinase II (CaMKII).