Objective To study the feasibility,effectiveness and safety of temporary pacing at the right ventricular outflow tract area in patients with inferior acute myocardial infarction(AMI)and two or three degree atrioventricular block(AVB). Methods Ninety-five patients with inferior AMI and two or three degree AVB admitted into Cangzhou People's Hospital were randomly divided into right ventricular apex pacing group(47 cases) and right ventricular outflow tract region pacing group(48 cases). Seldinger method was used to perform the right femoral vein puncture in which a 6F sheath tube was placed,and a diode temporary pacing electrode was introduced into it in the two groups. Under the X-ray guidance,in the right ventricular apex pacing group,the electrode was pushed from the inferior vena cava to enter into the right atrium,then cross the tricuspid and finally reach the right ventricular apical portion pacing. In the right ventricular outflow tract region pacing group,under the X-ray guidance, after the electrode was withdrawn and rotated slightly clockwise,it was sent forward to the right ventricular outflow tract region pacing. The duration from the puncture at the right femoral vein to the implanted electrode reaching the pacing region,the pacing threshold,the un-favorable pacing,the incidence of ventricular arrhythmia and prognosis were observed in the two groups. Results The pacing time and pacing threshold in right ventricular apex pacing group were obviously higher than those in the right ventricular outflow tract region pacing group〔pacing time(s):336±150 vs. 354±152,pacing threshold(V):0.9±0.4 vs. 0.7±0.3,both P<0.05〕. The mortality in intensive care unit (ICU)〔0(0/48)vs. 2.13%(1/47)〕,the incidence of bad pacing〔10.42%(5/48)vs. 17.02%(8/47)〕and ventricular fibrillation(VF),sustained ventricular tachycardia,contraction of non-sustained ventricular tachycardia or frequent ventricular premature beat(VPB)and other arrhythmia incidence of complications〔10.42%(5/48)vs. 12.77%(6/47)〕in the right ventricular outflow tract region pacing group were all lower than those in the right ventricular apex pacing group. Conclusion The application of right ventricular outflow tract pacing in patients with inferior AMI and two or three degree AVB is safe and effective,and its stability is fine.

Objective:To compare the clinical efficacy of robot-assisted percutaneous screw implantation and free-hand open screw implantation by Wiltse approach in the treatment of thoracolumbar fracture.Methods:A retrospective cohort study was performed to analyze the clinical data of 71 patients with thoracolumbar fracture admitted to Second Affiliated Hospital of Soochow University from May 2018 to May 2020. There were 52 males and 19 females, with age range of 22-54 years［(41.0±7.8)years］. Of all, 33 patients were treated with robot-assisted percutaneous screw implantation (Group A) and 38 patients were treated with free-hand open screw implantation by Wiltse approach (Group B). Following parameters were measured, including frequency of radiation exposure, operation time, intraoperative blood loss, length of hospital stay, incidence of complications, rate of fracture healing at 3 months and 6 months postoperatively, visual analogue scale (VAS) and Oswestry dysfunction index (ODI) at 3 days, 3 months, 6 months postoperatively and at the last follow-up, anterior vertebral body height ratio and sagittal Cobb angle preoperatively, at 3 days postoperatively and at the last follow-up, and rate of screw implantation of grade A and B and rate of facet joint violation at 3 days postoperatively.Results:All patients were followed up for 10-24 months［(15.2±4.4)months］. Frequency of radiation exposure and operation time showed no statistical differences between the two groups (both P>0.05). Intraoperative blood loss was 100(100, 135)ml in Group A, less than 160(120, 200)ml in Group B ( P<0.01). Length of hospital stay was 8(7, 11) days in Group A, shorter than 12(10, 16)days in Group B ( P<0.01). There were no complications such as infection, spinal nerve injury or cerebrospinal fluid leakage in both group. There were no significant differences between the two groups in the rate of fracture healing at 3 and 6 months postoperatively (all P>0.05). VAS and ODI in Group A was 3(2, 4)points and 21(18, 23)points at 3 days postoperatively, lower than 4 (3, 5)points and 27(20, 32)points in Group B ( P<0.05 or 0.01), and the two groups showed no significant differences in VAS and ODI at other time points (all P>0.05). There were no significant difference in the anterior vertebral body height ratio or sagittal Cobb angle between the two groups at 3 days postoperatively and at the last follow-up (all P>0.05). Rate of screw implantation of grade A and B was 96.5% (191/198) in Group A, higher than 90.4% (206/228) in Group B ( P<0.05). Rate of facet joint violation was 4.0%(8/198) in Group A, lower than 11.8% (27/228) in Group B ( P<0.01). Conclusion:For thoracolumbar fracture, robot-assisted percutaneous screw implantation is superior to free-hand open screw implantation by Wiltse approach in terms of less bleeding, shorter hospitalization, earlier pain alleviation, higher accuracy of screw implantation and lower risk of facet joint violation.

Objective: To understand the current situation and associated factors of myopia in junior middle school students, and to provide scientific basis for prevention and control of myopia in junior middle school students. Methods: A total of 5 393 junior middle school students were selected from middle schools in Guangdong, Guangxi, Guizhou, Liaoning, Shandong, Shanxi provinces. The visual acuity of middle school students was examined, and the data of general population, economy, sociology and natural environment were obtained through statistical yearbook of each province. The influencing factors of myopia of middle school students were analyzed by univariate and multivariate Logistic regression. Results: The results of single factor analysis showed that the myopia rate of junior high school students was different by gender, grades, parents average wage, sunshine duration, temperature, altitude, longitude and latitude(χ2=47.76，59.05，10.79，106.19，53.56，85.02，76.23，107.07，P<0.05). The results of multi factor analysis showed that gender, grade, average wage, temperature and latitude was positively associated with myopia vision; sunshine duration and longitude were negatively associated with the risk for myopia(OR=1.54，1.34，1.62，7.58，27.10，0.42，0.39，P<0.05). Conclusion The myopia of junior high school students is affected by a variety of factors, economic and social factors and natural environmental factors have an impact on the screening of sexual myopia in junior high school students. Economic and social factors and natural environmental factors should be taken into account in the formulation of myopia prevention and control measures.

Objective: To understand the current situation and associated factors of myopia among primary school students, and to provide scientific basis for prevention and control of myopia among primary school students. Methods: In Gansu, Guangdong, Guangxi, Guizhou, Liaoning, Shandong, Shanxi and other provinces, 1 prefecture was selected, and a number of primary schools were selected from each region. All the students in the class were selected as the object of this survey. A total of 8 365 middle school students were examined for their eyesight, and the data of general population economic indicators and natural environment indicators were obtained through the statistical yearbook of various provinces and cities. The influencing factors of primary school students myopia were analyzed by chi-square test and multivariate Logistic regression. Results: Univariate analysis showed that different provinces and different sex, different nationalities, different grade, parents average salary, sunshine duration, air temperature, altitude, longitude, latitude, different economic zone(χ2=116.22, 18.08, 26.33, 1 059.04, 14.86, 10.28, 16.95, 10.01, 23.15, 29.43, 88.14, P<0.05). Multivariate analysis results showed that gender, grade, sunshine duration, longitude were risk factor for poor vision(OR=1.31, 1.71, 1.45, 1.54, P<0.05); Economic zone and parents salary were protective factors for poor eyesight of students (OR=0.65, 0.86, P<0.05). Conclusion Myopia of primary school students is affected by a variety of factors, economic and social factors and natural environmental factors have an impact on the screening.