The HCN4 gene was closely related to various arrhythmias, and deletions or substitution mutations in exon bases of the HCN4 gene in patients with hereditary arrhythmias such as familial sinus bradycardia leading to alterations in the HCN4 channel protein, causing a significant reduction in the initiates the funny current and leading to a decrease in cardiac pacing function (40). The gene discussed is HCN4; the disease is Arrhythmia.