[Clinical features of unexpected sudden death clustered in 7 families in Yunnan Province].

OBJECTIVE: To investigate the clinical features of unexpected sudden death (SUD) clustered in families in Yunnan province. METHODS: This retrospective study analyzed the clinical features of SUD occurred between July to September 2005 in 7 families in Yunnan province. RESULTS: All 16 SUD patients shared common clinical features such as fatigue and repeated syncope and one group of SUD patients (n = 8 from 4 families) presented with the gastric intestinal tract manifestations including nausea, vomiting, abdominal pain and diarrhea with suspected dietary history and abnormal laboratory enzyme findings (GOT/GPT, CK/CKMB, LDH/LDH1 etc.). In SUD patients without gastric intestinal tract manifestations (n = 8 from 3 families), there were no clear symptoms before death and repeated ventricular tachycardia and ventricular fibrillation were recorded in one survivor. There was no clear evidence for the involvements of hereditary and infectious factors for observed SUD. CONCLUSION: The reason for the unexpected sudden death clustered in 7 families in Yunnan remains unclear. Repeated syncope and fatigue served as the common clinical features in the presence or absence of gastric intestinal tract manifestations in all SUD cases. Further studies are needed to clarify the pathology and detailed clinical manifestations of SUD occurred in this area.

[Pathological study of unexpected sudden death clustered in family or village in Yunnan province: report of 29 cases of autopsy].

OBJECTIVE: To investigate the pathological features and causes of sudden death clustered in family or village in Yunnan province so as to provide the morphological basis for exploring its etiology and medical intervention. METHODS: Autopsy was performed on 29 cases of clustered in family or village in Yunnan province during the period 1991-2006, 16 males and 13 females, aged 32 (8-69), accounting for 10.2% of whole sudden unexpected deaths occurring in the same period. The heart, lung, liver, spleen, brain, kidney, intestinal tract, and other organs were examined macroscopically and histologically, including a study of cardiac conduction system in 5 cases. Pathological diagnosis of myocarditis was based on the Dallas Criteria and World Heart Federation's consensus while the histological evaluation of Keshan disease referred the China national guideline for pathological diagnosis of Keshan disease. RESULTS: Based on the main pathological changes and the causes of death, these cases were classified into seven groups (group A-G). Group A comprised 11 cases (38%) with lymphocytic myocarditis accompanied with focal myocardial necrosis or degeneration. Group B comprised 3 cases (10%) with neutrophil myocarditis accompanied with focal myocytolysis or coagulation necrosis. Group C comprised 4 cases (14%) with arrhythmogenic right ventricle cardiomyopathy in which fatty infiltration of myocardium was the only pathological finding. Group D comprised 2 cases (7%) with ischemic heart disease in which fresh or old foci of myocardial infarction were found but coronary stenosis was shown only in one case. Group E comprised 2 cases (7%) with left ventricle hypertrophy and obstructive muscle bundle in the outflow of left ventricle. Group F comprised 2 cases (7%) with allergic bronchitis or chronic bronchitis and pulmonary emphysema. Group G comprised the remaining 5 cases (17%) without any pathological finding that could explain sudden death. No cases suffered with Keshan disease and dilated cardiomyopathy. Focal but not diffuse inflammatory infiltration was the prominent histological feature of myocarditis in Yunnan cases. Among the five cases with histological examination of cardiac conduction system, 2 cases were detected to suffer from acute hemorrhage in His bundle and its left branching site, and the atrioventricular node of 1 case was involved. Different pathological changes coexisted in 4 pairs of family members as a cluster of sudden deaths. 3 of 4 first deaths had focal myocarditis and the other one had chronic infection. But 3 secondary deaths had myocardial ischemia and the other one had arrhythmogenic right ventricle cardiomyopathy. Pulmonary edema, acute respiratory infection and congestive or ischemic liver necrosis were found in some cases simultaneously. CONCLUSION: The pathological changes of the cases of clustered sudden death in Yunnan province are various, such as myocarditis, myocardial dysplasia and the other lethal heart-lung disorders. No case of Keshan disease has been found. Arrhythmogenic right ventricle cardiomyopathy and other foundational heart diseases might act as a background. It is very hard to contribute only one etiological factor to the clustering of sudden death in Yunnan. It was most likely that multiple factors cluster and trigger an outbreak of death in a definite time and space.

[Study on clustering of Yunnan unexplained sudden death in household and village].

OBJECTIVE: To discuss the clustering of Yunnan unexplained sudden death (YUSD) in household and village. METHODS: Fifty-two cases were found by YUSD surveillance system in 2005. Poisson distribution and beta-binomial distribution (BBD) were employed in studying the household distribution of the disease. Poisson distribution and negative binomial distribution (NBD) were employed in studying the village distribution of the disease. RESULTS: BBD were fitted household distribution of YUSD very well (chi(2) = 0.25, P = 0.62), while Poisson distribution was consistent with it (chi(2) = 46.01, P < 0.001). And NBD were fitted village distribution of YUSD very well (chi(2) = 0.05, P = 0.58), however the consistency in Poisson distribution was not observed (chi(2) = 110.57, P < 0.001). CONCLUSION: Household and village clustering of YUSD does exist.

[Morphologic features of sudden cardiac death in Yunnan province, with emphasis on myocarditis].

OBJECTIVES: To study the pathologic feature of sudden cardiac death in Yunnan province and to investigate the role of myocarditis. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

[Electrocardiogram analysis in high risk population of unexplained sudden death in Yunnan province].

OBJECTIVE: The purpose of this study was to analyze the electrocardiographic features of the people living in the area with high incidence of unexplained sudden deaths in Yunnan province. METHOD: The electrocardiograms of 338 residents from three villages (Dayao, Ninglang, Heqing) with high incidence of unexplained sudden deaths and one control village (Dali) were analyzed [averaged age was (33.4 +/- 11.7) years, 175 men and 163 women]. RESULTS: The incidence of cardiac arrhythmias was similar low in all groups. The left ventricular hypertrophy was observed in 34.6% of residents from Dayao. QTc significantly prolonged in the residents from all 3 high incidence areas compare the control area of Dali [control (386.8 +/- 27.22) ms, Ninglang (428.92 +/- 25.71) ms, Heqing (440.67 +/- 28.03) ms, Dayao (417.7 +/- 24.00) ms, P < 0.05 vs. control]. Incidence of U wave was significantly higher in Heqing village than that in control village (P < 0.05). The QUc of these 3 villages was: (613.67 +/- 37.34) ms, (597.19 +/- 46.47) ms, (608.59 +/- 39.59) ms respectively, and also significantly longer than the control village of Dali (589.33 +/- 41.27) ms (P < 0.05). The typical pattern of U wave presents as enlarged U wave and apparent T-U complex. In the 7 residents who have the family history of unexplained sudden death, 6 residents have U wave, and 4 of them present typical U wave pattern. CONCLUSION: The significant ECG changes in villages with high incidence of unexplained sudden death in Yunnan province were prolonged QTc, enlarged U wave and apparent T-U complex and these ECG features suggested the repolarization abnormalities of the heart in these subjects.

[Retrospective study on 116 unexpected sudden cardiac deaths in Yunnan, China].

OBJECTIVE: To identify the epidemiological and clinical features of unexpected sudden cardiac deaths (SUD) in Yunnan. METHODS: 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. RESULTS: 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, P < 0.01) 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. CONCLUSIONS: 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.