Clinical characteristics of unexplained sudden cardiac death in Korea

In Western countries, sudden cardiac death (SCD) is closely related to coro nary artery disease, but in Korea the clinical characteristics of SCD are n ot well determined. Over a 4-year period (June 1995 to May 1999), 186 cases of SCD, ranging in age from 16 to 75 years, were admitted to the Chonnam N ational University Hospital. In 82 (44.1%) of these, neither symptoms nor e vidence of structural heart disease was found and so their clinical charact eristics were investigated. There were 66 (80.5%) men and 16 (19.5%) women (male/female ratio = 4.1: 1). The mean age was 50+/-14 years: 19 (23.2%) we re in their 40s, 21 (25.6%) in their 50s, and 17 (20.7%) in their 60s. The time of circulatory collapse witnessed in 68 cases of SCD showed 2 peaks: b etween midnight and 03.00h (n=16, 23.5%) and between 09.00 h and midday (n= 15, 22.1%). Unexplained SCD occurred at home in 48 (64.9%) cases and on the street in 12 (16.2%); it occurred during normal daily routine activity in 23 (39.6%) and during sleep in 15 (25.9%). Thirty-three patients (40.2%) ex perienced various prodromal symptoms, including chest discomfort (n=13, 15. 9%) and dyspnea (n=8, 9.8%). The electrocardiogram taken on arrival recorde d asystole in 65 (79.3%) and ventricular fibrillation in 17 (20.7%). Idiopa thic ventricular fibrillation was diagnosed in 14 (10 men, 4 women; 45+/-11 years) of 21 patients who recovered spontaneous circulation. Five (6.1%) p atients were discharged alive, and an implantable cardioverter-defibrillato r was implanted in 2. Unexplained SCD is common in Korea and develops predo minantly in middle-aged males around midnight or in the late morning usuall y with no prodromal symptoms (59.8%). Idiopathic ventricular fibrillation i s thought to be one of the important causes.