Objectives:To explore the association between the r'wave amplitude in lead V1 and impedance changes with left bundle branch pacing electrode implantation depth. Methods:A total of 78 patients with normal heart structure and underwent left bundle branch area pacing(LBBAP)in the Second Affiliated Hospital of Nanchang University from January 1,2019 to December 31,2021 were included in this retrospective analysis.Baseline data,intraoperative and imaging data,and 3,6,9 and 12 months of follow-up results were collected.Correlation and regression analysis were performed to define the feasibility using the r'wave in lead V1 during pacing and impedance changes to estimate the electrode depth. Results:r'waves at the end of the QRS complex in lead V1 during pacing were found in 70 cases(89.7%),and 8 cases(10.3%)showed rS,RS type QRS waves,or no r'wave at the end.Correlation analysis showed that r'wave amplitude was positively correlated with electrode depth(r=0.424,P<0.01),negatively correlated with impedance(r=-0.256,P=0.03).There was no significant statistical correlation between electrode implantation depth and impedance(r=-0.132,P=0.27).Regression analysis found that electrode depth was an important factor affecting r'wave amplitude(regression coefficient=0.056,P=0.000).Combined with the established regression model and impedance,it was found that the amplitude of the r'wave in lead V1 is at the range of 0.24-0.69 mV,and the impedance ranges from 648.30 to 828.90 Ω,and the electrode implantation depth is 6-11 mm,which is most suitable.The risk of perforation is low,and the left bundle branch can be successfully captured with a high probability.The pacing parameters are satisfactory,and the pacing QRS wave duration is narrow.During the intraoperative,postoperative 48 hours,and 12-month follow-up period,the patient did not experience complications such as electrode perforation,thromboembolism,cardiac tamponade,infection,or wire dislocation. Conclusions:Left bundle branch region pacing is a safe and feasible pacing method.During LBBAP,the amplitude of the r'wave in lead V1 at the range of 0.24-0.69 mV,and the impedance ranges from 648.30 to 828.90 Ω can be used to guide the pacing in the left bundle branch region and reduce the risk of electrode perforation.

Objective: To discuss the prevalence and influential factors of stroke among population in Jiangxi Province. Methods: Four cities in urban areas and four counties in rural areas were selected firstly, in which two districts or townships were selected; and then three communities or villages were chosen from each district and township, respectively, using the simple random sampling (SRS) method. Finally 15 269 subjects aging 15 years old or above, living in Jiangxi Province ≥6 months were randomly selected to participate in this survey from November 2013 to August 2014. Information of population characteristics, life behavior way, individual disease history were collected through questionnaire survey, and height, weight, waist circumference, blood pressure, body fat rate, visceral fat index and so on were measured by instruments. Risk factors of stroke prevalence were analyzed by the unconditioned logistic regression analysis. Results: A total of 15 269 participants (6 267 males) from 15 364 eligible participants were included in the statistical analysis. Out of which, 7 793 participants came from urban areas, and their average age was (53.04±17.91) years old. In this study, 226 stroke patients (117 males) were found among15 269 participants, including 122 urban participants and 104 rural participants, whose average age was (67.76±9.74) years old. The prevalence of stroke was 1 480.12/100 000 in 2014, which was separately 1 866.92/100 000 and 1 210.84/100 000 among males and females. The prevalence of people aging (45-49) years old was 413.79/100 000 (6/1 450) , while which among people aging 75 years old and above was 3 311.62/100 000 (61/1 842) . The prevalence of stroke among residents in Jiangxi presented an uprising tendency with age increasing (linear-by-linear association χ²=62.23, P<0.01). The research showed that when other influencing factors including gender, BMI, waist circumference, pulse-pressure difference, VAI, and sleeping time in non-working days were controlled, hypertensive patients had a higher risk of stroke than people without hypertension (OR=6.88, 95%CI: 4.90-9.67), drinkers had a higher risk of stroke than non-drinkers (OR=1.56, 95%CI: 1.17-2.08), compared with people <65 years old, people aged 65-74 years old and ≥75 years old had a higher risk of stroke, the value of OR (95%CI) were 1.88 (1.36-2.59) and 1.97 (1.39-2.80), respectively, compared with people with normal body fat percentage, people whose body fat percentage on high side and people who with high body fat percentage had a higher risk of stroke, the value of OR (95%CI) were 1.71 (1.18-2.48) and 1.74 (1.18-2.56), respectively, people with sleep time >8 h had a higher risk of stroke than those with sleep time of 6-8 h. Conclusion There was a high stroke prevalence among residents in Jiangxi province. Hypertension, drinking, age, BFP and sleep duration were associated with stroke prevalence. Corresponding measures for high-risk population and risk factors should be strengthened to prevent and control the stroke.