Qinghai Tibetans have lived under low oxygen pressure (hypoxia) conditions, which may alter the occurrence and development of certain diseases when compared with those of the lowland population.[17–19] However, in our study, the genotype and allele frequencies of SCN5A-H558R did not differ significantly between the AF and NAF groups at different altitudes; this finding should be verified using a larger cohort in the future. The gene discussed is SCN5A; the disease is atrial fibrillation.