Background: Many cases of sudden natural non-traumatic deaths (SNND) occur in individuals without known medical diseases. Many systems, more commonly cardiovascular and respiratory, are known to be involved in such deaths. This prospective autopsy based study was decided to determine the frequency of system involvement & survival period in sudden natural non-traumatic deaths. Material and Methods: During the study period from 1st October 2010 to 31st August 2012 total 1711 consecutive medico-legal autopsies were performed by the Department of Forensic Medicine and Toxicology, S.V.N. Government Medical College, Yavatmal, of which 125 (7.3%) cases were turned out to be of SNND, which were studied to determine the frequency of system involvement & survival period. Results: Maximum i.e. 41 (32.8%) cases were related to cardiovascular system causes followed by 32 (25.6%) to respiratory system causes. 17 (13.6%) cases related to central nervous system causes, 20 (16%) were related to gastrointestinal system causes, 05 (04%) due to genitourinary system causes and 10 (08%) were of miscellaneous causes. Out of cardiovascular causes, coronary artery disease contributed for 80.4% of cases. Out of total 125 cases, 71 (56.8%) cases survived less than 6 hours, 22 (17.6%) survived between 06 to 12 hours, 23 (18.4%) survived between 12 to 18 hours and 09 (7.2%) survived between 18 to 24 hours. It is pertinent to note that the primary system involved has had direct correlation with survival period. Out of cardiovascular cases, 37 (90.2%) survived less than 6:00 hours and 17 (41.5%) survived less than 1:00 hour. The system wise difference in period of survival was found to be statistically significant in hours (2= 46.91, p= 0.00003801). Average survival period for SNND cases was 06:56±0.26 hours and lowest i.e. 02:37±0.14 hours for deaths due to cardiovascular causes. Conclusion: Cardiovascular system pathologies remain the leading cause of sudden natural non-traumatic deaths with lowest survival period in this study. The people should undergo regular medical check-ups for early detection and proper management of cardiovascular diseases. Importance of survival period is for the assessment of suddenness of death, vulnerability of system and for future planning and providing of transport facilities and emergency medical service depots to cope with immediate events prior to death.

Keywords: Sudden Natural Non-Traumatic; Deaths; Autopsy; System Involvement; Survival Period.