Objective To evaluate peak rotation in the endocardium(endo)and epicardium(epi)and peak mural torsion in patients with anterior wall acute myocardial infarction(AMI)before and after revascularization by speckle tracking imaging(STI).Methods The study comprised 20 normal controls and 21 consecutive xpatients with a first-episode anterior wall AMI with stenosis of the left anterior descending artery.All patients underwent Successful percutaneous coronary intervention within 12h onset of AMI.During one month, two patients were ruled OUt because one died of heart failure and the other suffered from persistent atrial fibrillation.Conventional echocardiography and STI were performed in normal controls and AMI patients before and one month after revascularization.Results In the left ventricle(LV)apical and basal level,peak endo-and epi-rotation and peak mural torsion in AMI patients were significantly reduced relative to those of normal control group(all P<0.01).One month after revascularization,there were significant changes in these three variables,especially in peak endorotation(P<0.01).Peak apical endo-rotation positively correlated with LV ejection fraction(LVEF)(r=0.717,P<0.01)and inversely correlated with LV end-diastolic volume(EDV)(r=-0.694,P<0.05).However,tight relations were not found among other variables at the two planes.Conclusions Peak endo-and epi-rotation and peak mural torsion can make the sensitive assessment of abnormal myocardial contractile performancein AMI patients using STI.

Purpose　The aim is to study the preventing effect and me chanism of chitosan on fatty liver rats.Methods　The rats give n a lo w dose of carbon tetrachloride(CCl4) and fed a high-fat diet to induce fatty liver model were treated with chitosan in different concentrations.The extensio n of steatosis area and changes in mitochondrial ultrastructure in liver were es timated by a computer color image analysis system and a quantitative analysis(st ereology).Results　When rats were treated with a mid dose of c hitosan [4g/(kg*d)],the degree of hepatocytic steatosis was markedly diminished, and the injured mitochondrial structure was improved compared with model group.Co nclusion　It was suggested that chitosan might enhance the oxidative catabolism of lipid in fatty liver.

Aim: To study the effects of chitosan on hepatic lipids in fatty liver rats. Methods: The rats given a low does of carbon tetrachloride (CCl4) and fed a high-fat diet were treated with chitosan in different doses. Results: When rats were treated with mid dose of chitosan (4mg? g~-1?d~-1), the contents of triglycerde (TG). total cholesterol (TC) in liver decreased significantly, the level of mitochondria malonal-dialdehyde (MDA) was markedly attenuated and the mitochondria membrane fluidity was restored, which compared with model group. Conclusion: Chitosan may decrease the hepatic lipids by reduced the lipid peroxida- tion and restored mitochondria membrane fluidity to improve the mitochondrial beta-oxida- tion.

ObjectiveTo evaluate the alternations of left ventricular (LV) torsion of myocardial ischemia before and after reperfusion using speckle tracking imaging (STI).MethodsFourteen open-chest pigs underwent randomizedly 1 minute (group A) or 15 minutes (group B) of left anterior descending (LAD) ligation and followed up for 1 week.Torsion of LV in both groups were quantified by STI before LAD occlusion,LAD occlusion immediately,and 1-,5-,30-,60-,90-minute and 1-week after reperfusion.ResultsOne minute after reflow,decreased peak apical rotation and peak LV torsion fully recovered in the inner layer in group A.In contrast,there was a brief resumption in group B during 30min after reflow from (6.5 ± 0.8)° to (3.4 ± 1.2)°( P ＜0.01 ) and from (7.8 ± 1.0)° to (6.1 ± 1.1 ) ° ( P ＜0.01 ),respectively.Peak LV subepicardial torsion increased gradually after reperfusion.Conclusions As a result of various durations of ischemia,peak torsion in subendocardium and subepicardium change differently before and after reflow.STI may be suitable for evaluation of the extent of ischemia by noninvasive quantification of torsion in subendocardium and subepicardium.Therefore,duration of assessment of myocardial ischemia can be prolonged.

Objective To investigate the most sensitive markers of left ventricular(LV) torsion which can reflect infarct size by assessing the relationship between routine markers of LV torsion and infarct size using speckle tracking imaging (STI).Methods Fifteen open-chest pigs underwent 120 minutes of left anterior descending (LAD) ligation followed by 12 hours of reperfusion.Rotation and torsion of LV were obtained by STI before LAD occlusion,LAD occlusion immediately,and 30,60,90 minutes and 12 hours after reperfusion.Infarct size was measured by nitrotetrazolium blue chloride staining.Results LAD ligation resulted in a dramatic decrease in both subepicardial and subendocardial peak apical rotation or peak LV torsion.Twelve hours after reperfusion,all of the peak rotation and torsion remained significantly reduced (P ＜ 0.01 versus AMI).At AMI,peak bulk LV torsion and peak bulk apical rotation inversely correlated with infarct size (r = - 0.81,P ＜0.01; r = - 0.69,P ＜0.01).There existed the good relationship at 12-hour follow-up after reperfusion.The relationship was superior to that of other torsion markers.Conclusions Peak bulk LV torsion and peak bulk apical rotation are the most sensitive markers of LV torsion which can reflect infarct size.

Objectives:To evaluate the strategy and clinical outcomes of reimplanting biventricular cardiac resynchronization therapy (Biv-CRT) devices after transvenous removal of coronary sinus left ventricular leads due to device-related infections. Methods:A retrospective analysis was conducted on the clinical data and surgical outcomes of all patients who underwent transvenous removal of infectious coronary sinus left ventricular leads and subsequent reimplantation of Biv-CRT devices at Peking University People's Hospital from January 2013 to December 2022.Follow-up was performed to assess the incidence of complications and all-cause mortality. Results:A total of 167 patients underwent coronary sinus left ventricular lead removal due to infection,removal was successful in 161 cases (96.4％) and failed in 6 cases (3.6％).Among the patients with successful removal,109 cases (67.7％) were scheduled for Biv-CRT device reimplantation.After a median time of 7 (5,7) days,6 cases (5.5％) of reimplantation failed,while 103 reimplantations (94.5％) were successful.Among these successful reimplantation cases,102 patients (99.0％) were through the right-side approach,and 1 case (1.0％) through the left-side approach due to bilateral pocket infections.Of the 161 patients with successful removal,58 cases (36.0％) did not undergo left ventricular lead reimplantation,including 39 cases (24.2％) where the initial indications for Biv-CRT were questionable or had resolved.During the one-year postoperative follow-up,among the 103 patients who had undergone Biv-CRT device reimplantation,7 patients (6.8％) died,1 patient (1.0％) experienced pocket infection,and 1 patient (1.0％) had right atrial lead dislodgment. Conclusions:Reimplantation of Biv-CRT devices after removal of coronary sinus left ventricular leads due to infections is feasible,with a high success rate,low complication rate,and low mortality rate for right-side approach implantation.Therefore,for patients re-evaluated to have indications for repeated Biv-CRT after lead removal,right-side reimplantation of the coronary sinus left ventricular lead should be recommended.

Objective: To investigate the action and antioxidant effects of CB2 agonist AM-1241 on rat hepatic stellate cell line (HSC-T6). Methods: HSC-T6 was randomly divided into four groups: control group, oxidative stress group, AM-1241 intervention group and AM-1241+AM-630 antagonist group. Survival rate of HSC-T6 was detected by thiazolyl blue assay under 24 h interventions with 0, 20, 50, 80 μmol/L AM-1241 and 0, 10, 20, 30, 40 μmol/L AM-630, respectively. Besides control group, the remaining groups were well cultured in low-glucose DMEM containing 100 mU/L glucose oxidase (GO) for 12 h to prepare the oxidative stress model. Then, AM-1241 intervention group was treated with 50 μmol/L low-glucose DMEM medium. After incubation for 12 h, the AM-1241+AM-630 antagonist group was treated with CB2 antagonist AM-630 (20 μmol/L) for 2 h, and cultured with 50 μmol/L AM-1241 in complete low-glucose medium for 12 h. The optimal drug concentration was selected according to the cell viability considered by the experiment results. Type III collagen (C III) content in the HSC-T6 supernatant was detected by enzyme-linked immunosorbent assay. Glutathione (GSH) content in HSC-T6 was detected by spectrophotometry. CB2 and heme oxygenase-1(HO-1) in each group of HSC-T6 were detected by western blotting. Results: HSC-T6 proliferation was inhibited in each group of AM-1241 in a concentration-dependent manner (P < 0.05). The inhibition was highest at 80μmol/L, and the cell survival rate was (41.61% ± 3.13%) (P < 0.05). AM-630 concentration group had no significant inhibitory effect on the proliferation of HSC-T6 (P > 0.05). HSC-T6 expressed CB2 receptor in each group. The expression level of CB2 in the AM-1241 intervention group was higher compare with control group (P < 0.05).The expression of Col III were significantly higher in oxidative stress group (P < 0.05) than in control group, and the expression of Col III of AM-1241 intervention group was significantly lower than that in oxidative stress group (P < 0.05). Col III level in AM-1241+AM-630 antagonistic group was significantly higher than that in AM-1241 intervention group (P < 0.05). There was no significant difference between AM-1241+AM-630 antagonistic group and oxidative stress group (P > 0.05). The content of GSH and HO-1 in oxidative stress group was higher (P < 0.05) than control group. The content of GSH and HO-1 in the AM-1241 intervention group was higher compared with oxidative stress group, while content of AM-1241 + AM-630 antagonist group was lower compared to AM-1241 intervention group (P < 0.05), and the differences were not statistically significant for oxidative stress group. Conclusion CB2 agonist AM-1241 can inhibit the proliferation and activation of HSC-T6 and its mechanism may activate the nuclear translocation of Nrf2 binding to HSC-T6, initiating the up-regulation of antioxidant enzymes HO-1 and GSH protein expression, and thus increase the antioxidant effect of HSC-T6.

Objective:To evaluate the safety of leadless pacemaker implantation in super-elderly patients.Methods:Eleven patients with average age of 90 (86, 92) years who underwent leadless pacemaker implantation in the Department of Cardiology, Peking University People′s Hospital from March 2021 to May 2022 were included. The clinical data and implantation information were collected. The complications (cardiac tamponade, myocardial infarction, cerebral infarction, pulmonary embolism, pacemaker reinfection, femoral vein hematoma) and death of patients were documented at 24 h, 3 d, and 1, 3, 6 months after pacemaker implantation.Results:There were 9 males and 2 females with the body mass index of 21(19, 23)kg/m 2. The underlying diseases were hypertension, diabetes, coronary heart disease, chronic kidney disease, chronic obstructive pulmonary disease, previous cerebral infarction and moderate to severe tricuspid regurgitation in 9, 9, 9, 6, 4, 4, 4 patients, respectively. The left ventricular ejection fraction was 49% (45%, 52%), the hemoglobin concentration was 118 (114, 122)g/L, 4 patients were taking anticoagulant drugs, and 6 patients were taking antiplatelet drugs. Eight patients were newly implanted with a leadless pacemaker, 2 patients were implanted after removal the old ones, and 1 case was implanted at the same time as removal. The implantation time was 45(40, 47) minutes, the X-ray exposure time was 14 (13, 15) minutes, the release time was 1 (1, 2), the threshold value was 0.50(0.38, 0.75)V/0.24 ms, the impedance was 730 (700, 770) Ω, and the perceived R-wave amplitude 8.2(6.7, 12.8) mV. During the follow-up period of 8 (6, 10) months, no patient had pacemaker dysfunction; and the threshold, R wave sensing, and impedance were stable and maintained within the normal range. No cardiac tamponade, myocardial infarction, cerebral infarction, pulmonary embolism, pacemaker reinfection or death occurred perioperatively and during the follow-up period; 1 patient had hematoma after femoral vein puncture, which improved after compression treatment. Conclusion:This single-center and small-sample study shows that leadless pacemaker implantation is safe for super-elderly patients.

Objectives:To evaluate the safety and efficacy of implantation of subcutaneous implantable cardioverter defibrillator(S-ICD)after transvenous lead extraction(TLE)in ICD patients without pacing indications. Methods:All patients who underwent TLE at Peking University People's Hospital from June 2018 to October 2023 were consecutively included.TLE indication,S-ICD implantation indication,defibrillation threshold(DFT)test,complications and postoperative follow-up were collected and analyzed. Results:A total of 11 patients with TV-ICD underwent S-ICD implantation after TLE,eight patients were males and median age were 56(44,65)years.The indications for TLE were infection and lead dysfunction.Nine patients were implanted with S-ICD for secondary prevention,and the most common cause of implantation was ion channelopathies(5 cases).The operative time for S-ICD was 51(48,58)minutes and no perioperative complications were noted.Eight patients underwent DFT testing,and 100%were successful.During a median follow up of 30(9,39)months,a total of six appropriate treatments occurred in two patients,and no complications occurred,including inappropriate treatment,ineffective treatment,infection,lead malfunction and death. Conclusions:Our study provides evidence for S-ICD implantation as a replacement after TV-ICD removal.The S-ICD implantation after TLE is safe and effective.

0.05 ). After once injection both observers considered the number of clearly recognized endocardial border segments increased significantly. The number evaluated by observers A increased from 2.68 ? 0.95 to 5.99 ? 0.10 while from 2.82 ? 1.03 to 5.99 ? 0.11 by observers B( P 0.05 ). The average contrast enhancement rate of LV endocardial border was 99.7 %. Perfluoropropane-albumin microsphere injection had no significant effection on vital signs such as blood prssure, heart rate and respiration. Electrocardiogram didn′t change markedly and the variance of the laboratory findings like blood and urine routine examination, hepatic and renal function was in normal range. Only one case( 0.33 %) had slight side-effects who suffered from mild nausea and diarrhea, which suggested the clinical safety of this contrast agent. Conclusions Perfluoropropane-albumin microsphere injection could enhance the resolution of LV endocardial borders and make the judgement of regional myocardial movement easier. It has little side-effects and will be appropriate for clinical use.