Sudden cardiac death (SC D ),m ostcom m only seen in coronary heart disease, is a kind of sud-den death caused by series of cardiac param eters, w hich usually com bines w ith m yocardial infarction. H ow ever, som e SC D s (including early m yocardial infarction) happen suddenly and cause death in a very short tim e. In these circum stances, typical m orphological changes are lack in m acroscopic or m icroscopic fields, w hich m ake such SC D s becom e the em phasis and difficulty in the present research. SC D caused by m yocardial infarction and abnorm alities of cardiac conduction system (C C S ) is related to atheroscle-rosis of coronary artery closely. T his paper review s cardiac dysfunction caused by m yocardial infarction and diseases of C C S from m orphology and m olecular biology, and explores potential relationship be-tw een them . T his paper aim s to provide clues to the m echanism of m yocardial infarction related sudden death and possible assistance for forensic diagnosis of SC D .

Objective To analyze the miss rates of colorectal adenomas during colonoscopy as well as risk factors influencing the adenoma miss rates and to take corresponding measures. Methods A total of 432 patients who underwent index and follow-up colonoscopy in 18 months were randomized and investigated. The results of two colonoscopies were compared and the missed adenomas were defined as the adenomas de-tected only during the second colonoscopy. Miss rates were calculated according to patient-based methods. Chi-square test was used to analyze the relative factors influencing the adenoma miss rate of per-patient. Then the meaningful factors were chosen into the logistic regression model for multiple factors analysis. Results Of 432 patients,116(26. 9%)had missed adenomas on first colonoscopy. Single factor analysis found that the size of adenoma( χ2 = 89. 686,P = 0. 000),the shape of adenoma( χ2 = 68. 488,P = 0. 000),the location of adenoma(χ2 = 77. 055,P = 0. 000)and adenoma tissue types(χ2 = 417. 000,P = 0. 000)were the risk factors for miss rates of colorectal adenomas. Number of polyps(χ2 = 8. 450,P= 0. 038),the organi-zation type of polyp(χ2 = 10. 718,P= 0. 013)and proficiency of colonoscopists(χ2 = 56. 069,P= 0. 000), the quality of bowel preparation(χ2 = 39. 195,P = 0. 000),insertion time(χ2 = 13. 133,P = 0. 001)were also the risk factors for miss rates of colorectal adenomas. Logistic regression analysis showed that the bigger the adenoma size,the less missed adenomas(OR= 0. 341,95%CI:0. 173-0. 671). Also,the longer insertion time took,the lower the adenoma miss rate(OR = 0. 987,95% CI:0. 981-0. 994). Per-patient miss rates were lower for high-risk adenomas compared with low-risk adenomas(OR = 0. 324,95%CI:0. 154-0. 680). Adenomas happening in multiple parts of bowel easily leads to missing(OR= 3. 791,95%CI:1. 505-9. 546). Conclusion The missed diagnosis of adenomas is not only significantly associated with features of missed adenomas,but also with skills of colonoscopists,insertion time,and bowel preparation. The key is high-quality index colonoscopy to avoid adenomas missing.