[Past histories of sudden death without specific underlying disease]

To study past histories of patients who died suddenly, we selected cases from all the summary death certificates in which death occurred within 24 hours from the onset of symptoms spanning 1984 to 1986 in Niigata prefecture with a population of 2.5 million. We then re-examined all information on the death certificates to determine the underlying causes. Sudden deaths due to cardiovascular diseases other than acute myocardial infarction and cerebrovascular accident (OCD) accounted for the largest proportion (51.4%). The proportion of death of unknown etiology increased with the decrease in age in both sexes aged 15 to 54 years, accounting for 67.8% in males and 51.1% in females. The number of cases with histories of diseases related to atherosclerosis (e.g. hypertension, old cerebrovascular accident, etc) increased with age in both sexes, accounting for 38.5% in males and 36.4% in females, both aged 75 years old and over. Except diseases related to atherosclerosis, the past histories accounted for 2.5% or greater were as follows: alcoholism (4.1%), psychiatric disorder (PSY, 2.9%) and valvular heart diseases (VD, 2.6%) in 15-54-year-old males; ischemic heart diseases (IHD, 9.4%), arrhythmia without organic heart diseases (ARR, 2.5%) and VD (2.5%) in 55-74-year-old male; IHD (11.4%), bronchial asthma (3.7%), common cold within one month (CC, 3.6%), cor pulmonale or its related diseases (3.0%) and ARR (2.6%) in male of 75 years old and over; PSY (8.7%), IHD (5.8%), VD (5.1%), pregnancy, delivery or related diseases (4.4%), chronic renal failure (3.6%) and CC (2.9%) in 15-54-year-old females; IHD (10.2%), VD (3.2%) and ARR (2.6%) in 55-74-year-old females; and IHD (11.8%) in females of 75 years old and over. When diseases related to atherosclerosis were included, half of the sudden death cases due to OCD had past histories of underlying cause. As descriptions of past histories are often incomplete, there were probably more cases with past histories. The results of this study indicate that investigation of past histories may aid in elucidating and preventing sudden death.