[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.

[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.