Abstract: Sudden unexplained nocturnal death syndrome （SUNDS） is always a difficulty in forensic medicine researches. Although the development of molecular genetics promotes the etiologic study of SUNDS, the pathogenesis of most such cases is still unclear. Sleep apnea syndrome （SAS） is one of the common forms of sleep disorders, and obstructive sleep apnea hypopnea syndrome （OSAHS） is the most common. In recent years, some domestic and international researches show that OSAHS is related to the development of cardiovascular disease, which may cause cardiac arrhythmia, even sudden death. This article reviews the relationship between SUNDS and OSAHS and aims to provide new ideas for the pathogenesis of SUNDS.

Key words: forensic pathology, sleep apnea, obstructive, review, arrhythmia, cardiac, sudden unexplained nocturnal death syndrome