Types of Septic Cardiomyopathy: Prognosis and Influencing Factors - A Clinical Study.

Objective: To explore the prognostic outcomes associated with different types of septic cardiomyopathy and analyze the factors that exert an influence on these outcomes. Methods: The data collected within 24 hours of ICU admission included cardiac troponin I (cTnI), N-terminal pro-Brain Natriuretic Peptide (NT-proBNP); SOFA (sequential organ failure assessment) scores, and the proportion of vasopressor use. Based on echocardiographic outcomes, septic cardiomyopathy was categorized into left ventricular (LV) systolic dysfunction, LV diastolic dysfunction, and right ventricular (RV) systolic dysfunction. Differences between the mortality and survival groups, as well as between each cardiomyopathy subgroup and the non-cardiomyopathy group were compared, to explore the influencing factors of cardiomyopathy. Results: A cohort of 184 patients were included in this study, with LV diastolic dysfunction having the highest incidence rate (43.5%). The mortality group had significantly higher SOFA scores, vasopressor use, and cTnI levels compared to the survival group; the survival group had better LV diastolic function than the mortality group (p < 0.05 for all). In contrast to the non-cardiomyopathy group, each subgroup within the cardiomyopathy category exhibited elevated levels of cTnI. The subgroup with left ventricular diastolic dysfunction demonstrated a higher prevalence of advanced age, hypertension, diabetes mellitus, coronary artery disease, and an increased mortality rate; the RV systolic dysfunction subgroup had higher SOFA scores and NT-proBNP levels, and a higher mortality rate (P < 0.05 for all); the LV systolic dysfunction subgroup had a similar mortality rate (P > 0.05). Conclusion: Patients with advanced age, hypertension, diabetes mellitus, or coronary artery disease are more prone to develop LV diastolic dysfunction type of cardiomyopathy; cardiomyopathy subgroups had higher levels of cTnI. The RV systolic dysfunction cardiomyopathy subgroup had higher SOFA scores and NT-proBNP levels. The occurrence of RV systolic dysfunction in patients with sepsis significantly increased the mortality rate.

Implication of geriatric nutritional risk index on treatment response and long-term prognosis in patients with cardiac resynchronization therapy.

PURPOSE: Geriatric Nutritional Risk Index (GNRI) is a simple tool for assessing the nutritional status of the aging population. This study aims to explore the clinical implication of GNRI on treatment response and long-term clinical outcomes in heart failure (HF) patients receiving cardiac resynchronization therapy (CRT). METHODS: Patients who underwent CRT implantation or upgrade at our hospital were retrospectively included. The association of GNRI and its tertiles with the echocardiographic response, all-cause mortality or heart transplantation, and the first hospitalization due to HF were investigated. RESULTS: Totally, 647 patients were enrolled, with a median age of 60 [Interquartile Range (IQR): 52-67] years and mean score of GNRI at 107.9 ± 23.7. Super-response rates increased significantly among the GNRI T1, T2, and T3 groups (25.1%, 29.8% vs. 41.1%, P = 0.002). Patients with higher GNRI were more likely to have better LVEF improvement after multiple adjustments (OR = 1.13, 95% CI: 1.04-1.23, P = 0.010). Higher GNRI was independently associated with a lower risk of all-cause mortality or heart implantation (HR = 0.95, 95% CI: 0.93-0.96, P < 0.001) and HF hospitalization (HR = 0.96, 95% CI: 0.95-0.98, P < 0.001). The inclusion of GNRI enhanced the predictability of all-cause mortality based on traditional model, including sex, New York Heart Association functional class, left bundle branch block, QRS reduction, and N-terminal pro-B-type natriuretic peptide level (C statistics improved from 0.785 to 0.813, P = 0.007). CONCLUSION: Higher GNRI was associated with better treatment response and long-term prognosis in HF patients with CRT. Evaluation of nutritional status among CRT population is necessary for individualized choice of potential responders.

Rapamycin improves the long-term T-cell memory and protective efficacy of tuberculosis subunit vaccine.

The formation of long-lived T-cell memory is a critical goal of vaccines against intracellular pathogens like Mycobacterium tuberculosis (M. tuberculosis). In this study, to access the adjuvant effect of rapamycin on tuberculosis subunit vaccine, we treated mice with rapamycin during the course of vaccination and then monitored the vaccine-specific long-term memory T cell recall responses and protective ability against mycobacterial organisms. Compared with the mice that received vaccine alone, rapamycin treatment enhanced the vaccine induced long-term IFN-γ and IL-2 recall responses, promoted the development of TCM (central memory) like cells and improved the long-term proliferative ability of lymphocytes. Long-duration (total 53 days) of low-dose rapamycin (75 µg/kg/day) treatment generated stronger vaccine-specific memory T cell responses than short-duration treatment (total 25 days). Moreover, rapamycin improved the vaccine's long-term protective efficacy, which resulted in a better reduction of 0.89-log10 CFU of mycobacterial organisms in the lungs compared with control without rapamycin treatment. These findings suggest that rapamycin may be considered in designing TB subunit vaccine regimens or as potential adjuvant to enhance vaccine-induced T cell memory response and to prolong the longevity of vaccine's protective efficacy.

Dyssynchronous heart failure models in canines: New insights into electrocardiographic, echocardiographic and histological features.

BACKGROUND: We investigated the similarities and differences between two experimental approaches using tachy-pacing technology to induce desynchronized heart failure in canines. METHODS: A total of eight dogs were included in the experiment, four were tachy-paced in right ventricle apex (RVAP) and 4 were paced in right atrium after the ablation of left bundle branch to achieve left bundle branch block (RAP+LBBB). Three weeks of follow-up were conducted to observe the changes in cardiac function and myocardial staining was performed at the end of the experiment. RESULTS: Both experimental approaches successfully established heart failure with reduced ejection fraction models, with similar trends in declining cardiac function. The RAP+LBBB group exhibited a prolonged overall ventricular activation time, delayed left ventricular activation, and lesser impact on the right ventricle. The RVAP approach led to a reduction in overall right ventricular compliance and right ventricular enlargement. The RAP+LBBB group exhibited significant reductions in left heart compliance (LVGLS, %: RAP+LBBB -12.60 ± 0.12 to -5.93 ± 1.25; RVAP -13.28 ± 0.62 to -8.05 ± 0.63, p = 0.023; LASct, %: RAP+LBBB -15.75 ± 6.85 to -1.50 ± 1.00; RVAP -15.75 ± 2.87 to -10.05 ± 6.16, p = 0.035). Histological examination revealed more pronounced fibrosis in the left ventricular wall and left atrium in the RAP+LBBB group while the RVAP group showed more prominent fibrosis in the right ventricular myocardium. CONCLUSION: Both approaches establish HFrEF models with comparable trends. The RVAP group shows impaired right ventricular function, while the RAP+LBBB group exhibits more severe decreased compliance and fibrosis in left ventricle.

Effect of short-term cardiac function changes after cardiac resynchronization therapy on long-term prognosis in heart failure patients with and without diabetes.

Background: The relationship between short-term cardiac function changes and long-term outcomes in heart failure (HF) patients undergoing cardiac resynchronization therapy (CRT) remains uncertain, especially when stratified by diabetes status. Objectives: This study aims to assess the association between short-term cardiac function changes and outcomes such as all-cause mortality and HF hospitalization in patients undergoing CRT, stratified by diabetes status. Design: This is a cohort longitudinal retrospective study. Methods: A total of 666 HF patients, treated with CRT between March 2007 and March 2019, were included in this study. Among them, 166 patients (24.9%) were diagnosed with diabetes. Cardiac function was assessed at baseline and again at 6 months, incorporating evaluations of left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVEDD), left atrial diameter (LAD), N-terminal prohormone of brain natriuretic peptide (NT-proBNP), and QRS duration. The QRS duration represents the time required for a stimulus to spread through the ventricles (ventricular depolarization). The primary endpoints of the study were all-cause mortality and HF-related hospitalization. Results: During a median follow-up of 2.51 years, 172 (25.8%) patients died and 197 (29.6%) were hospitalized for HF. Changes in LVEF, LVEDD, and LAD within 6 months had similar effects on adverse outcomes in both diabetic and nondiabetic patients. However, the presence of diabetes significantly modified the association between changes in NT-proBNP and QRS duration and adverse outcomes. Short-term changes in NT-proBNP and QRS duration were positively associated with all-cause mortality and HF hospitalization in patients without diabetes. However, the relationship between short-term changes in NT-proBNP and QRS duration and adverse outcomes was non-linear in diabetic patients. Conclusion: Improvement of cardiac function after CRT implantation can reduce long-term risk of all-cause mortality and HF hospitalization in HF patients. However, the presence of diabetes may affect the association between short-term changes in NT-proBNP and QRS duration and adverse outcomes.

A self-powered intracardiac pacemaker in swine model.

Harvesting biomechanical energy from cardiac motion is an attractive power source for implantable bioelectronic devices. Here, we report a battery-free, transcatheter, self-powered intracardiac pacemaker based on the coupled effect of triboelectrification and electrostatic induction for the treatment of arrhythmia in large animal models. We show that the capsule-shaped device (1.75 g, 1.52 cc) can be integrated with a delivery catheter for implanting in the right ventricle of a swine through the intravenous route, which effectively converts cardiac motion energy to electricity and maintains endocardial pacing function during the three-week follow-up period. We measure in vivo open circuit voltage and short circuit current of the self-powered intracardiac pacemaker of about 6.0 V and 0.2 µA, respectively. This approach exhibits up-to-date progress in self-powered medical devices and it may overcome the inherent energy shortcomings of implantable pacemakers and other bioelectronic devices for therapy and sensing.

Metabolomics Profiling Predicts Ventricular Arrhythmia in Patients with an Implantable Cardioverter Defibrillator.

Implantable cardioverter defibrillators (ICDs) reduce sudden cardiac death (SCD) when patients experience life-threatening ventricular arrhythmias (LTVA). However, current strategies determining ICD patient selection and risk stratification are inefficient. We used metabolomics to assess whether dysregulated metabolites are associated with LTVA and identify potential biomarkers. Baseline plasma samples were collected from 72 patients receiving ICDs. Over a median follow-up of 524.0 days (range 239.0-705.5), LTVA occurred in 23 (31.9%) patients (22 effective ICD treatments and 1 SCD). After confounding risk factors adjustment for age, smoking, secondary prevention, and creatine kinase MB, 23 metabolites were significantly associated with LTVA. Pathway analysis revealed LTVA associations with disrupted metabolism of glycine, serine, threonine, and branched chain amino acids. Pathway enrichment analysis identified a panel of 6 metabolites that potentially predicted LTVA, with an area under the receiver operating characteristic curve of 0.8. Future studies are necessary on biological mechanisms and potential clinical use.

Joint association of sedentary behavior and vitamin D status with mortality among cancer survivors.

BACKGROUND: Sedentary behavior and vitamin D deficiency are independent risk factors for mortality in cancer survivors, but their joint association with mortality has not been investigated. METHODS: We analyzed data from 2914 cancer survivors who participated in the National Health and Nutrition Examination Survey (2007-2018) and followed up with them until December 31, 2019. Sedentary behavior was assessed by self-reported daily hours of sitting, and vitamin D status was measured by serum total 25-hydroxyvitamin D (25(OH)D) levels. RESULTS: Among 2914 cancer survivors, vitamin D deficiency was more prevalent in those with prolonged daily sitting time. During up to 13.2 years (median, 5.6 years) of follow-up, there were 676 deaths (cancer, 226; cardiovascular disease, 142; other causes, 308). The prolonged sitting time was associated with a higher risk of all-cause and noncancer mortality, and vitamin D deficiency was associated with a higher risk of all-cause and cancer mortality. Furthermore, cancer survivors with both prolonged sitting time (≥ 6 h/day) and vitamin D deficiency had a significantly higher risk of all-cause (HR, 2.05; 95% CI: 1.54-2.72), cancer (HR, 2.33; 95% CI, 1.47-3.70), and noncancer mortality (HR, 1.91; 95% CI, 1.33-2.74) than those with neither risk factor after adjustment for potential confounders. CONCLUSIONS: In a nationally representative sample of U.S. cancer survivors, the joint presence of sedentary behavior and vitamin D deficiency was significantly associated with an increased risk of all-cause and cancer-specific mortality.

Construction and evaluation of a novel multi-antigenic Mycobacterium tuberculosis subunit vaccine candidate BfrB-GrpE/DPC.

Tuberculosis poses a significant threat to human health due to the lack of an effective vaccine. Although promising progress has been made in the development of tuberculosis vaccines, new vaccines that broaden the antigenic repertoire need to be developed to eradicate this illness. In this study, we used Mycobacterium tuberculosis ferritin BfrB and heat-shock protein GrpE to construct a novel multi-antigenic fusion protein, BfrB-GrpE (BG). BG protein was stably overexpressed in the soluble form in Escherichia coli at a high yield and purified via sequential salt fractionation and hydrophobic chromatography. Purified BG was emulsified in an adjuvant containing N, N'-dimethyl-N, N'-dioctadecylammonium bromide, polyinosinic-polycytidylic acid, and cholesterol (DPC) to construct the BG/DPC vaccine, which stimulated strong cellular and humoral immune responses in mice. Moreover, combination of BG with our previously developed vaccine, Mtb10.4-HspX (MH), containing antigens from both the proliferating and dormant stages, significantly reduced the bacterial counts in the lungs and spleens of M. tuberculosis-infected mice. Importantly, mice that received BG + MH/DPC after M. tuberculosis H37Rv infection survived slightly better (100% survival) than those that received the BCG vaccine (80% survival), although the difference was not statistically significant. Our findings can aid in the selection of antigens and optimization of vaccination regimens to improve the efficacy of tuberculosis vaccines.

High antipersister activity of a promising new quinolone drug candidate in eradicating uropathogenic Escherichia coli persisters and persistent infection in mice.

AIMS: To develop more potent drugs that eradicate persister bacteria and cure persistent urinary tract infections (rUTIs). METHODS AND RESULTS: We synthesized eight novel clinifloxacin analogs and measured minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), the time-kill curves in uropathogenic Escherichia coli (UPEC) UTI89, and applied the candidate drugs and combinations against biofilm bacteria in vitro and in mice. Transcriptomic analysis was performed for UPEC after candidate drug treatment to shed light on potential mechanism of action. We identified Compound 2, named Qingdafloxacin (QDF), which was more potent than clinafloxacin and clinically used levofloxacin and moxifloxacin, with an MIC of < 0.04 µg ml-1 and an MBC of 0.08∼0.16 µg ml-1. In drug combination studies, QDF + gentamicin + nitrofuran combination but not single drugs completely eradicated all stationary phase bacteria containing persisters and biofilm bacteria, and all bacteria in a persistent UTI mouse model. Transcriptome analysis revealed that the unique antipersister activity of QDF was associated with downregulation of genes involved in bacterial stress response, DNA repair, protein misfolding repair, pyrimidine metabolism, glutamate, and glutathione metabolism, and efflux. CONCLUSIONS: QDF has high antipersister activity and its drug combinations proved highly effective against biofilm bacteria in vitro and persistent UTIs in mice, which may have implications for treating rUTIs.

Effectiveness of adding a defibrillator with cardiac resynchronization therapy in heart failure according to the modified Model for End-stage Liver Disease-Albumin score.

Current guidelines lack clear recommendations between the implantation of cardiac resynchronization therapy (CRT) with defibrillator (CRT-D) and CRT with pacemaker (CRT-P). We hypothesized that modified model for end-stage liver disease score including albumin (MELD-Albumin score), could be used to select patients who may not benefit from CRT-D. We consecutively included patients with CRT-P or CRT-D implantation between 2010 and 2022. The primary endpoint was the composite of all-cause mortality or worsening heart failure. We performed multivariable-adjusted Cox proportional hazard regression. We assessed the interaction between the MELD-Albumin score and the effect of adding a defibrillator with CRT.A total of 752 patients were included in this study, with 291 implanted CRT-P. During a median follow-up of 880 days, 205 patients reached the primary endpoint. MELD-Albumin score was significantly associated with the primary endpoint in the CRT-D group [HR 1.16 (1.09-1.24); P < 0.001] but not in the CRT-P group [HR 1.03 (0.95-1.12); P = 0.49]. There was a significant interaction between the MELD-Albumin score and the effect of CRTD (P = 0.013). The optimal cut-off value of the MELD-Albumin score was 12. For patients with MELD-Albumin ≥ 12, CRT-D was associated with a higher occurrence of the primary endpoint [HR 1.99 (1.10-3.58); P = 0.02], whereas not in patients with MELD-Albumin < 12 [HR 1.19 (0.83-1.70); P = 0.35). Our findings suggest that CRT-D is associated with an excess risk of composite clinical endpoints in HF patients with higher MELD-Albumin score.

Effects of donepezil treatment on plasma and urine metabolites in amyloid beta-induced Alzheimer's disease rats.

Accumulated clinical and biomedical evidence suggests that abnormalities in systemic metabolic processes such as fatty acid and amino acid metabolism can affect the brain function and behavior of various central nervous system diseases such as Alzheimer's disease (AD). In this study, metabolic profiling was used to investigate changes in plasma and urine metabolites following stereotactic injection of amyloid ß (Aß) and treatment with donepezil in rats. Aß causes cognitive impairment, while donepezil treatment successfully improves memory impairment. Donepezil improves Aß-induced plasma fatty acid and bile acid metabolism disorders, as well as Aß-induced urine phenylalanine and tryptophan metabolism disorders in rats. More specifically, the plasma fatty acids improved by donepezil include alpha-linolenic acid, stearidonic acid, eicosapentaenoic acid, docosahexaenoic acid, linoleic acid, arachidonic acid, oleic acid, and palmitic acid, among others. Additionally, donepezil significantly restored the downregulation of bile acids such as ursodeoxycholic acid, cholic acid, and glycocholic acid caused by Aß. As for urine metabolites, phenylacetylglycine, epinephrine, and other phenylalanine metabolites, as well as kynurenic acid, xanthurenic acid, and other tryptophan metabolites, were worsened by Aß and improved by donepezil. These findings suggest that the cognitive impairment induced by Aß and the improvement by donepezil are associated with changes in metabolic disorders in rats. This study provides basic data for the effects of Aß and donepezil on plasma and urine metabolites in Aß-induced AD rat models.

Glutamate Transporters GltS, GltP and GltI Are Involved in Escherichia coli Tolerance In Vitro and Pathogenicity in Mouse Urinary Tract Infections.

To verify the roles of GltS, GltP, and GltI in E. coli tolerance and pathogenicity, we quantified and compared the relative abundance of gltS, gltP, and gltI in log-phase and stationary-phase E. coli and constructed their knockout mutant strains in E. coli BW25113 and uropathogenic E. coli (UPEC) separately, followed by analysis of their abilities to tolerate antibiotics and stressors, their capacity for adhesion to and invasion of human bladder epithelial cells, and their survival ability in mouse urinary tracts. Our results showed that gltS, gltP, and gltI transcripts were higher in stationary phase E. coli than in log-phase incubation. Furthermore, deletion of gltS, gltP, and gltI genes in E. coli BW25113 results in decreased tolerance to antibiotics (levofloxacin and ofloxacin) and stressors (acid pH, hyperosmosis, and heat), and loss of gltS, gltP, and gltI in uropathogenic E. coli UTI89 caused attenuated adhesion and invasion in human bladder epithelial cells and markedly reduced survival in mice. The results showed the important roles of the glutamate transporter genes gltI, gltP, and gltS in E. coli tolerance to antibiotics (levofloxacin and ofloxacin) and stressors (acid pH, hyperosmosis, and heat) in vitro and in pathogenicity in mouse urinary tracts and human bladder epithelial cells, as shown by reduced survival and colonization, which improves our understanding of the molecular mechanisms of bacterial tolerance and pathogenicity.

Sex differences in the nonlinear association of triglyceride glucose index with all-cause and cardiovascular mortality in the general population.

BACKGROUND: The evidence on the association between the triglyceride glucose (TyG) index and the risk of death in the general population remains controversial. This study aims to investigate the relationship between the TyG index and all-cause and cardiovascular mortality in the general population, with a focus on sex differences. METHODS: This prospective cohort study analyzed data from the National Health and Nutrition Examination Survey (1999-2002), comprising 7,851 US adults. The study employed multivariate Cox proportional hazards regression and two-segment Cox hazard regression models to evaluate the sex-specific differences in the relationship between the TyG index and all-cause and cardiovascular mortality. RESULTS: After 11,623 person-years of follow-up, there were 539 deaths, with 10.56% due to all-cause mortality and 2.87% due to cardiovascular mortality. After adjusting for multiple variables, our study found a U-shaped association of the TyG index with all-cause and cardiovascular mortality, with inflection points at 9.36 and 9.52. A significant sex difference was observed in the association between the TyG index and mortality. Below the inflection point, the relationship between the TyG index and mortality was consistent in males and females. However, above the inflection point, only males exhibited a positive association between the TyG index and all-cause mortality (adjusted hazard risk [HR], 1.62, 95% confidence interval [CI], 1.24-2.12) and cardiovascular mortality (adjusted HR, 2.28, 95% CI, 1.32-3.92). CONCLUSIONS: Our study showed a U-shaped association between the TyG index and all-cause and cardiovascular mortality in the general population. Furthermore, sex differences were observed in the association between the TyG index and mortality once it exceeded a certain threshold.

Early Diastolic Peak Velocity of Mitral Valve Annulus and Right Ventricular Systolic Tricuspid Annular Velocity as Predictors in Assessing Prognosis of Patients with Sepsis.

Objective: To analyze the epidemiological data of patients with septic cardiomyopathy and investigate the relationship between ultrasonic parameters and prognosis of patients with sepsis. Methods: In this study, we enrolled patients with sepsis who were treated at the Department of Critical Care Medicine in the Beijing Electric Power Hospital (No.1 Taipingqiao Xili, Fengtai District, Beijing) from January 2020 to June 2022. All patients received standardized treatment. Their general medical status and 28-day prognosis were recorded. Transthoracic echocardiography was performed within 24 hours after admission. We compared the ultrasound indexes between the mortality group and the survival group at the end of 28 days. We included parameters with significant difference in the logistic regression model to identify the independent risk factors for prognosis and evaluated their predictive value using receiver operating characteristic (ROC) curve. Results: We included 100 patients with sepsis in this study; the mortality rate was 33% and the prevalence rate of septic cardiomyopathy was 49%. The peak e' velocity and right ventricular systolic tricuspid annulus velocity (RV-Sm) of the survival group were significantly higher than those of the mortality group (P < 0.05). Results of logistic regression analysis showed that the peak e' velocity and RV-Sm were independent risk factors for prognosis. The area under curve of the peak e' velocity and the RV-Sm was 0.657 and 0.668, respectively (P < 0.05). Conclusion: The prevalence rate of septic cardiomyopathy in septic patients is high. In this study, we found that the peak e' velocity and right ventricular systolic tricuspid annulus velocity were important predictors of short-term prognosis.

The impact of chronotropic incompetence on atrioventricular conduction times in heart failure patients.

BACKGROUND: Intrinsic atrioventricular (AV) conduction is used to optimize AV intervals with cardiac resynchronization therapy (CRT) in most device algorithms. Atrial pacing and heart rate affect conduction times, but little is known regarding differeces among chronotropic incompetent(CI) and competent(CC) patients to guide programming. METHODS: RAVE was a multicenter prospective trial of CRT patients. Heart rate was increased with incremental atrial pacing and with submaximal exercise. According to the maximal heart rate achieved during exercise, patients were classified as either CI or CC. For CI patients, an additional symptom-limited exercise with rate-adaptive pacing activated was performed. Intracardiac intervals were measured from the implantable lead electrograms in multiple postures. RESULTS: There were 12 subjects with CI and 24 with CC. With atrial pacing, AV interval immediately increased and gradually increased with incremental atrial pacing in all patients. However, the changes in the atrial to right ventricular (ARV) and atrial to left ventricular (ALV) intervals with increasing atrial pacing rates were about threefold greater in CI patients compared to CC patients (24.3 ± 28.9 vs. 7.2 ± 5.5 ms/10 bpm for ARV and 22.7 ± 25.6 vs. 7.1 ± 5.7 ms/10 bpm for ALV in the standing position, p < 0.05). In CI pacing with rate-adaptive pacing during exercise, AV interval changes with paced heart rate were variable. CONCLUSIONS: The AV response to overdrive atrial pacing at rest may provide a simple means of identifying chronotropic competence in CRT patients. For patients with CI, who often require rate-adaptive atrial pacing, rate-adaptive AV algorithms should be adjusted individually.

A novel approach for developing left bundle branch pacing and left bundle branch block in a canine model.

BACKGROUND AND OBJECTIVE: Left bundle branch pacing (LBBP) has shown the benefits in the treatment of dyssynchronous heart failure (HF). The purpose of this study was to develop a novel approach for LBBP and left bundle branch block (LBBB) in a canine model. METHODS: A "triangle-center" method by tricuspid valve annulus angiography for LBBP implantation was performed in 6 canines. A catheter was then applied for retrograde His potential recording and left bundle branch (LBB) ablation simultaneously. The conduction system was stained to verify the "triangle-center" method for LBBP and assess the locations of the LBB ablation site in relation to the left septal fascicle (LSF). RESULTS: The mean LBB potential to ventricular interval and stimulus-peak left ventricular activation time were 11.8 ± 1.2 and 35.7 ± 3.1 ms, respectively. The average intrinsic QRS duration was 44.7 ± 4.7 ms. LBB ablation significantly prolonged the QRS duration (106.3 ± 8.3 ms, p < .001) while LBBP significantly shortened the LBBB-QRS duration to 62.5 ± 5.3 ms (p < .001). After 6 weeks of follow-up, both paced QRS duration (63.0 ± 5.4 ms; p = .203) and LBBB-QRS duration (107.3 ± 7.4 ms; p = .144) were unchanged when comparing to the acute phase, respectively. Anatomical analysis of 6 canine hearts showed that the LBBP lead-tip was all placed in LSF area. CONCLUSION: The new approach for LBBP and LBBB canine model was stable and feasible to simulate the clinical dyssynchrony and resynchronization. It provided a useful tool to investigate the basic mechanisms of underlying physiological pacing benefits.

Clinical outcome of lesion size index-guided high-power radiofrequency catheter ablation for pulmonary vein isolation in patients with atrial fibrillation: 2-year follow-up.

INTRODUCTION: The long-term efficacy of high-power (50 W) ablation guided by lesion size index (LSI-guided HP) for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF) remains undetermined. Our study sought to assess the clinical efficacy of LSI-guided HP ablation for PVI in patients with AF and explore the potential predictors associated with clinical outcomes. METHODS: We consecutively included 186 patients with AF who underwent LSI-guided HP (50 W) ablation at Fuwai Hospital from June 2019 to October 2021. The target LSI values of 4.5-5.5 and 4.0-4.5 at the anterior and posterior walls, respectively, were used in our study. The baseline clinical characteristics, procedural and ablation data, and clinical outcomes were evaluated. The independent potential predictors associated with AF recurrence were further evaluated. RESULTS: The incidence rate of first-pass PVI was 83.9% (156/186). A total of 11 883 lesions were analyzed, and compared with posterior walls of pulmonary veins, anterior walls had significantly lower mean contact force (8.2 ± 3.0 vs. 8.3 ± 2.3 g, p = .015), longer mean radiofrequency duration (16.9 ± 7.2 vs. 12.9 ± 4.5 s, p < .001) and higher mean LSI (4.8 ± 0.2 vs. 4.4 ± 0.2, p < .001). The overall incidence of periprocedural complications was 3.7%, and steam pops without pericardial effusion occurred in three patients (1.6%). During a mean follow-up of 24.0 ± 8.4 months, the overall AF recurrence-free survival was 87.1% after a single procedure. Patients with paroxysmal AF had a higher incidence of freedom from AF recurrence than those with persistent AF (91.2% vs. 80.8%, log-rank p = .034). Higher LSI (HR 0.50, p < .001) and paroxysmal AF (HR 0.39, p = .029) were significantly associated with decreased AF recurrence. By receiver operating characteristic analysis, the LSI of 4.7 and 4.3 for the anterior and posterior walls of the PVs had the highest predictive value for AF recurrence, respectively. CONCLUSION: LSI-guided HP (50 W) ablation for PVI was an efficient and safe strategy and led to favorable single-procedure 2-year AF recurrence-free survival in patients with AF. Higher LSI and paroxysmal AF were independent predictors of decreased 2-year AF recurrence. The LSI of 4.7 for the anterior wall and 4.3 for the posterior wall of the PVs were the best cutoff values for predicting AF recurrence after LSI-guided HP ablation.

Advances of Implantation Techniques for Conduction System Pacing.

Conduction system pacing (CSP), including His bundle and left bundle branch pacing are physiological pacing modalities, but lead deployment is often difficult mainly due to a lack of anatomical landmark for lead tip location. Several implantation techniques for CSP implantation have been developed including 3-dimensional electroanatomical mapping, placing a second lead as a reference (dual-lead method technique), and using fluoroscopic imaging (9-partition and visualization techniques). In this review, the authors summarize the implantation techniques for CSP and compare the different methods.