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To study the pathologic feature of sudden cardiac death in Yunnan province and to investigate the role of myocarditis.During the period from 1991 to 2006, there were 29 cases of sudden cardiac death with autopsy performed. Fourteen of these cases were diagnosed to have myocarditis based on Dallas criteria and World Heart Federation's consensus. The clinical and pathologic findings were reviewed. The cardiac conduction system was examined in details by serial sectioning in 3 cases.Fourteen cases suffered with myocarditis, which accounted for 48% of all cases of sudden cardiac death studied. The age of the deceased ranged from 8 to 68 years (mean = 30 years), with male-to-female ratio equaled to 9:5. Lymphocytic myocarditis and neutrophil myocarditis were the two major types, affecting 11 and 3 cases, respectively. The inflammatory infiltrates were often patchy rather than diffuse. The inflammatory foci were detected only in 8% to 42% (average = 20%) of the paraffin sections of the heart tissue. These lesions were usually located in the lateral wall of left ventricle and occasionally in interventricular septum and right ventricular wall. Myocardial injury was mild in most cases while patchy myocytolysis or coagulation necrosis was observed only in a few cases. Most of the lesions were relatively new and histologic evidence of myocardial repairing sometimes coexisted. Pericarditis and subacute endocarditis were also identified in 4 and 1 cases, respectively. Atrioventricular node was involved by myocarditis in 1 of the 3 cases examined for cardiac conduction system. Two cases showed gross evidence of cardiac dilatation (either left ventricle or biventricular). Respiratory tract and pulmonary infection was present in 5 cases.Myocarditis represents one of the major pathologic changes of sudden cardiac death occurring in Yunnan province. The inflammation is usually focal. Further studies are required for delineation of possible etiologies which may include virus, bacteria or exogenous toxin.

To understand the epidemiologic and clinical characteristics of the "Yunnan unknown-cause sudden cardiac death (YUSCD)".Cases of YUSCD occurred in 2002-2004 were investigated with cross-sectional study. Clinical manifestation was observed and analyzed.The YUSCD areas were mountainous and most of the YUSCD cases appeared between June and August. Most of the YUSCD cases were young farmers and showed family/village clustering nature. Most of the patients died quickly with only few recovered. The overall incidence of YUSCD was 1.83% with mortality as 1.51%. The fatality rate of YUSCD appeared to be 78.1%.The YUSCD cases had a clustering feature along with time and area. The clinical manifestation of YUSCD could not be specifically identified, making the clinical diagnosis and treatment difficult when practicing in the fields that called for further studies on epidemiology, clinical work and etiology.

To identify the epidemiological and clinical features of unexpected sudden cardiac deaths (SUD) in Yunnan.Choosing the old SUD cases from Xiangyun, Heqing, Nanjian and Dayao counties and using the standardized verbal autopsy Form, we interviewed the family members of the cases, witnesses and doctors as well as reviewing their medical files to get relative information.We identified 116 SUDs in 21 villages from 1984 to 2004. The village-specific annually standardized incidence rates were ranged from 0.2/1000 to 8.9/1000 (median = 0.8/1000). 66% and 29% of the SUDs occurred in July and August respectively. The incidence rates of SUD were higher (1.6/1000, chi(2) = 16, P0.01) in 10 - 39 year-olds, and higher in females than in males (RR = 1.6, 95% CI: 1.1 - 2.3). Seventy percent of SUD occurred in families having clustering nature and 60% of the additional cases in the family were occurred within 24 hours (median = 20 hours) after the first SUD identified in the family. SUD occurred in 23 families followed the first affected family in a village during the same season. In these 23 families, 61% of the first SUD occurred within 8 days after the first SUD in the first affected family. 68% and 66% of the SUDs did not have any complaints or signs during the last 3 weeks or from 3 weeks to 2 days prior to the onset of the disease. 63% of the SUDs had cardiac symptoms within the last 2 days prior to the onset with major symptoms as dizziness, nausea, faintness, unconsciousness, weakness and palpitation. The median duration from acute onset to death was 2 hours.The extreme time-space clustering of SUD in families and in villages suggested that the risk factors occurred in specific time and location. Familial clustered SUD cases had common exposure pattern. Sudden onset of acute cardiac symptoms often followed by sudden death. Epidemiological study on new cases was necessary to identify risk factors and to develop hypothesis for causation. In July 2005, we instituted a special SUD surveillance system for all the affected counties together with 10 counties which had no reported cases.