The methods for improving the biodegradability of oily sludge: a critical review.

Biological degradation method, as an environmentally friendly, low-carbon, and clean pollution treatment technology, is widely used for the harmless disposal of oily sludge. The biodegradability of oily sludge with stable emulsification system, high oil, and water content is poor. Therefore, it is necessary to pre-treat the oily sludge to improve its biodegradability, including recover the petroleum resources and remove heavy metals and bio-toxic organic matters. This review systematically summarizes five oily sludge treatment methods and their influences on sludge biodegradability, including pyrolysis, chemical hot washing, solvent extraction, chemical oxidation, and hydrothermal. Pyrolysis at temperatures above 750 °C produces high molecular weight polycyclic aromatic hydrocarbons, chemical hot washing and chemical oxidation would cause secondary pollution, solvent extraction method could not be applied due to the high cost and high toxicity of the extractant, and the oil removal of hydrothermal method is inefficient. Additionally, the principles, advantages, and disadvantages of those treatments and the factors affecting microbial degradation were analyzed, which provide the development direction of pretreatment technology to improve the biodegradability of oily sludge.

Methods and clinical biomarker discovery for targeted proteomics using Olink technology.

PURPOSE: This paper is to offer insights for designing research utilizing Olink technology to identify biomarkers and potential therapeutic targets for disease treatment. EXPERIMENTAL DESIGN: We discusses the application of Olink technology in oncology, cardiovascular, respiratory and immune-related diseases, and Outlines the advantages and limitations of Olink technology. RESULTS: Olink technology simplifies the search for therapeutic targets, advances proteomics research, reveals the pathogenesis of diseases, and ultimately helps patients develop precision treatments. CONCLUSIONS: Although proteomics technology has been rapidly developed in recent years, each method has its own disadvantages, so in the future research, more methods should be selected for combined application to verify each other.

Research on the Cold Rolling Process, Microstructure and Properties of 305 Austenitic Stainless Steel Thin Strips.

Austenitic stainless steel has high toughness and plasticity; however, it tends to exhibit low yield strength, which severely limits the widespread application of this steel. It can be strengthened by cold working; however, this will cause many defects in the structure. Therefore, annealing treatment must be carried out before use. In this paper, the effects of annealing treatment at different temperatures and times on the microstructure and mechanical properties of cold-rolled 305 stainless steel sheet were studied and the theoretical mechanism was further analyzed to provide better theoretical guidance for production and application. It was found that the microstructure grains obtained by annealing at 850 °C for 30 s were finer and more uniform, and the mechanical properties were also the best, which met the requirements of strong plasticity. Therefore, the rolling and annealing experiments could be carried out again under this annealing condition, and the requirements of the finished product could be finally obtained. At this time, the thickness of the plate was about 0.15 mm, the yield strength was 1238 MPa, and the permeability was below 1.02, which met the production requirements of the metal mask plate.

CISD2 promotes lung squamous carcinoma cell migration and invasion via the TGF-B1-induced Smad2/3 signaling pathway

Background Although aberrant expression of CDGSH iron sulfur domain 2 (CISD2) contributes to the tumorigenesis and progression of numerous human cancers, the biological function of CISD2 and its specific prognostic value in lung squamous cell carcinoma (LUSC) have yet to be comprehensively explored. The current study aimed to elucidate the role of CISD2 in LUSC as well as the underlying molecular mechanisms. Methods Immunohistochemistry was conducted to detect the protein expression of CISD2 and analyze whether high expression of CISD2 affects the overall survival (OS) of LUSC patients. Cell proliferation, colony formation, wound healing and Transwell invasion assays were performed to clarify whether CISD2 contributes to LUSC cell proliferation and disease progression. Quantitative real-time reverse transcription-PCR and western blot assays were used to detect the levels of transcription factors and key epithelial-mesenchymal transition (EMT)-related markers in LUSC cells after CISD2 knockdown and overexpression to determine whether CISD2 regulates transforming growth factor-beta (TGF-β)-induced EMT in LUSC. Results Immunohistochemistry of human tissue microarrays containing 90 pairs of adjacent and cancerous tissues revealed that CISD2 is considerably overexpressed in LUSC and strongly linked to poor OS. Functional experiments suggested that silencing endogenous CISD2 inhibited the growth, colony formation, migration, and invasion of H2170 and H226 cell lines. Exogenous overexpression of CISD2 facilitated these phenotypes in SK-MES-1 and H2170 cells. Furthermore, CISD2 promoted EMT progression by increasing the expression of mesenchymal markers (N-cadherin, vimentin, Snail, and Slug) as well as SMAD2/3 and reducing the expression of the epithelial marker E-cadherin. Mechanistically, our studies provide the first evidence that CISD2 can promote EMT by enhancing TGF-β1-induced Smad2/3 expression in LUSC cells (AU)

Proteomic advance of ischemic stroke: preclinical, clinical, and intervention.

Ischemic stroke (IS) is the most common type of stroke and is characterized by high rates of mortality and long-term injury. The prediction and early diagnosis of IS are therefore crucial for optimal clinical intervention. Proteomics has provided important techniques for exploring protein markers associated with IS, but there has been no systematic evaluation and review of research that has used these techniques. Here, we review the differential proteins that have been found in cell- and animal- based studies and clinical trials of IS in the past 10 years; determine the key pathological proteins that have been identified in clinical trials; summarize the target proteins affected by interventions aimed at treating IS, with a focus on traditional Chinese medicine treatments. Overall, we clarify findings and problems that have been identified in recent proteomics research on IS and provide suggestions for improvements in this area. We also suggest areas that could be explored for determining the pathogenesis and developing interventions for IS.

CISD2 promotes lung squamous carcinoma cell migration and invasion via the TGF-ß1-induced Smad2/3 signaling pathway.

BACKGROUND: Although aberrant expression of CDGSH iron sulfur domain 2 (CISD2) contributes to the tumorigenesis and progression of numerous human cancers, the biological function of CISD2 and its specific prognostic value in lung squamous cell carcinoma (LUSC) have yet to be comprehensively explored. The current study aimed to elucidate the role of CISD2 in LUSC as well as the underlying molecular mechanisms. METHODS: Immunohistochemistry was conducted to detect the protein expression of CISD2 and analyze whether high expression of CISD2 affects the overall survival (OS) of LUSC patients. Cell proliferation, colony formation, wound healing and Transwell invasion assays were performed to clarify whether CISD2 contributes to LUSC cell proliferation and disease progression. Quantitative real-time reverse transcription-PCR and western blot assays were used to detect the levels of transcription factors and key epithelial-mesenchymal transition (EMT)-related markers in LUSC cells after CISD2 knockdown and overexpression to determine whether CISD2 regulates transforming growth factor-beta (TGF-ß)-induced EMT in LUSC. RESULTS: Immunohistochemistry of human tissue microarrays containing 90 pairs of adjacent and cancerous tissues revealed that CISD2 is considerably overexpressed in LUSC and strongly linked to poor OS. Functional experiments suggested that silencing endogenous CISD2 inhibited the growth, colony formation, migration, and invasion of H2170 and H226 cell lines. Exogenous overexpression of CISD2 facilitated these phenotypes in SK-MES-1 and H2170 cells. Furthermore, CISD2 promoted EMT progression by increasing the expression of mesenchymal markers (N-cadherin, vimentin, Snail, and Slug) as well as SMAD2/3 and reducing the expression of the epithelial marker E-cadherin. Mechanistically, our studies provide the first evidence that CISD2 can promote EMT by enhancing TGF-ß1-induced Smad2/3 expression in LUSC cells. CONCLUSION: In conclusion, our research illustrates that CISD2 is highly expressed in LUSC and may facilitate LUSC proliferation and metastasis. Thus, CISD2 may serve as an independent prognostic marker and possible treatment target for LUSC.

Characterization and mechanisms of radioresistant lung squamous cell carcinoma cell lines.

BACKGROUND: Radiotherapy is an important clinical treatment for patients with lung squamous cell carcinoma (LUSC), and resistance to radiotherapy is an important cause of recurrence and metastasis in LUSC. The aim of this study was to establish and explore the biological characteristics of radioresistant LUSC cells. MATERIALS AND METHODS: The LUSC cell lines NCI-H2170 and NCI-H520 were irradiated (4 Gy × 15Fraction). Radiosensitivity, cell apoptosis, cell cycle, and DNA damage repair were measured by clonogenic survival assay, flow cytometry, immunofluorescence for γ-H2AX foci, and Comet assay, respectively. Activation of p-ATM(Ser1981), p-CHK2(Th68), p-DNA-PKcs (Ser2056), and Ku70/Ku80 was measured by western blot. Proteomics was used to explore the differential genes and enriched signaling pathways between radioresistant cell lines and parental lines. In vivo nude mouse xenograft experiments further verified the feasibility of the radioresistant LUSC cell lines. RESULTS: After fractionated irradiation (total dose of 60 Gy), radioresistant cells had decreased radiosensitivity, increased G0/G1 phase arrest, enhanced DNA damage repair ability, and through the ATM/CHK2 and DNA-PKcs/Ku70 pathways regulated double strands break. The upregulated differential genes in radioresistant cell lines were mainly enriched in biological pathways such as cell migration and extracellular matrix (ECM)-receptor interaction. In vivo verification of decreased radiosensitivity of radioresistant cells CONCLUSIONS: Radioresistant LUSC cell lines were established by fractional radiotherapy, which regulates IR-induced DNA damage repair through ATM/CHK2 and DNA-PKcs/Ku70. Tandem Mass Tags (TMT) quantitative proteomics found that the biological process pathway of cell migration and ECM-receptor interaction are upregulated in LUSC radioresistant cells.

MFN2 deficiency affects calcium homeostasis in lung adenocarcinoma cells via downregulation of UCP4.

Mitofusin-2 (MFN2) is a transmembrane GTPase that regulates mitochondrial fusion and thereby modulates mitochondrial function. However, the role of MFN2 in lung adenocarcinoma remains controversial. Here, we investigated the effect of MFN2 regulation on mitochondria in lung adenocarcinoma. We found that MFN2 deficiency resulted in decreased UCP4 expression and mitochondrial dysfunction in A549 and H1975 cells. UCP4 overexpression restored ATP and intracellular calcium concentration, but not mtDNA copy number, mitochondrial membrane potential or reactive oxygen species level. Furthermore, mass spectrometry analysis identified 460 overlapping proteins after independent overexpression of MFN2 and UCP4; these proteins were significantly enriched in the cytoskeleton, energy production, and calponin homology (CH) domains. Moreover, the calcium signaling pathway was confirmed to be enriched in KEGG pathway analysis. We also found by protein-protein interaction network analysis that PINK1 may be a key regulator of MFN2- and UCP4-mediated calcium homeostasis. Furthermore, PINK1 increased MFN2/UCP4-mediated intracellular Ca2+ concentration in A549 and H1975 cells. Finally, we demonstrated that low expression levels of MFN2 and UCP4 in lung adenocarcinoma are associated with poor clinical prognosis. In conclusion, our data suggest not only a potential role of MFN2 and UCP4 in co-regulating calcium homeostasis in lung adenocarcinoma but also their potential use as therapeutic targets in lung cancer.

Dynamic Regulation Genes at Microtubule Plus Ends: A Novel Class of Glioma Biomarkers.

Glioma is the most prevalent and aggressive primary nervous system tumor with an unfavorable prognosis. Microtubule plus-end-related genes (MPERGs) play critical biological roles in the cell cycle, cell movement, ciliogenesis, and neuronal development by coordinating microtubule assembly and dynamics. This research seeks to systematically explore the oncological characteristics of these genes in microtubule-enriched glioma, focusing on developing a novel MPERG-based prognostic signature to improve the prognosis and provide more treatment options for glioma patients. First, we thoroughly analyzed and identified 45 differentially expressed MPERGs in glioma. Based on these genes, glioma patients were well distinguished into two subgroups with survival and tumor microenvironment infiltration differences. Next, we further screened the independent prognostic genes (CTTNBP2, KIF18A, NAV1, SLAIN2, SRCIN1, TRIO, and TTBK2) using 36 prognostic-related differentially expressed MPERGs to construct a signature with risk stratification and prognostic prediction ability. An increased risk score was related to the malignant progression of glioma. Therefore, we also designed a nomogram model containing clinical factors to facilitate the clinical use of the risk signature. The prediction accuracy of the signature and nomogram model was verified using The Cancer Genome Atlas and Chinese Glioma Genome Atlas datasets. Finally, we examined the connection between the signature and tumor microenvironment. The signature positively correlated with tumor microenvironment infiltration, especially immunoinhibitors and the tumor mutation load, and negatively correlated with microsatellite instability and cancer stemness. More importantly, immune checkpoint blockade treatment and drug sensitivity analyses confirmed that this prognostic signature was helpful in anticipating the effect of immunotherapy and chemotherapy. In conclusion, this research is the first study to define and validate an MPERG-based signature closely associated with the tumor microenvironment as a reliable and independent prognostic biomarker to guide personalized choices of immunotherapy and chemotherapy for glioma patients.

Premature beat of selective left bundle branch: a novel marker for reaching and capturing the left bundle branch.

BACKGROUND: It was recently shown that template beats and fixation beats of the premature ventricular contractions (PVCs) were generated during lead deployment. These could be exploited to guide the left bundle branch (LBB) pacing (LBBP) procedure. However, lack of a revolving connector that can continuously record and pace during lead rotations has been a limitation when using the traditional implant technique. Here, we report ten cases in which a revolving connector was used and showed that the premature beats of selective left bundle branch (SLBB-PBs) were generated as the lead was reached and the electrical stimulus selectively captured the LBB. METHODS AND RESULTS: Ten patients who underwent the transseptal placement of the pacing lead using a revolving connector were included in the study. We aimed to examine whether the SLBB-PB was a marker of LBB capture during LBBP and the clinical significance of SLBB-PB. LBBP was performed and data of these cases were analyzed to show the characteristics of the electrocardiogram and the intracardiac electrogram of SLBB-PBs. CONCLUSIONS: This is the first case series on SLBB-PBs in LBBP. The presence of SLBB-PBs suggested that the LBB was reached and selectively captured and possibly increased the safety of lead implantation.

Comorbidity and healthcare utilization in patients with treatment resistant depression: A large-scale retrospective cohort analysis using electronic health records.

BACKGROUND: Medical comorbidity and healthcare utilization in patients with treatment resistant depression (TRD) is usually reported in convenience samples, making estimates unreliable. There is only limited large-scale clinical research on comorbidities and healthcare utilization in TRD patients. METHODS: Electronic Health Record data from over 3.3 million patients from the INSIGHT Clinical Research Network in New York City was used to define TRD as initiation of a third antidepressant regimen in a 12-month period among patients diagnosed with major depressive disorder (MDD). Age and sex matched TRD and non-TRD MDD patients were compared for anxiety disorder, 27 comorbid medical conditions, and healthcare utilization. RESULTS: Out of 30,218 individuals diagnosed with MDD, 15.2 % of patients met the criteria for TRD (n = 4605). Compared to MDD patients without TRD, the TRD patients had higher rates of anxiety disorder and physical comorbidities. They also had higher odds of ischemic heart disease (OR = 1.38), stroke/transient ischemic attack (OR = 1.57), chronic kidney diseases (OR = 1.53), arthritis (OR = 1.52), hip/pelvic fractures (OR = 2.14), and cancers (OR = 1.41). As compared to non-TRD MDD, TRD patients had higher rates of emergency room visits, and inpatient stays. In relation to patients without MDD, both TRD and non-TRD MDD patients had significantly higher levels of anxiety disorder and physical comorbidities. LIMITATIONS: The INSIGHT-CRN data lack information on depression severity and medication adherence. CONCLUSIONS: TRD patients compared to non-TRD MDD patients have a substantially higher prevalence of various psychiatric and medical comorbidities and higher health care utilization. These findings highlight the challenges of developing interventions and care coordination strategies to meet the complex clinical needs of TRD patients.

A Continuous Pacing and Recording Technique for Differentiating Left Bundle Branch Pacing From Left Ventricular Septal Pacing: Electrophysiologic Evidence From an Intrapatient-Controlled Study.

BACKGROUND: Left bundle branch pacing (LBBP) is a promising approach for achieving near-physiologic pacing. However, differentiating LBBP from left ventricular septal endocardial pacing (LVS(e)P) remains a challenge. This study aimed to establish a simple and effective method for differentiating LBBP from LVS(e)P and to evaluate their electrophysiologic characteristics. METHODS: LBBP, using continuous uninterrupted pacing and real-time monitoring of electrocardiograms along with intracardiac electrograms, was performed in 97 consecutive patients. We evaluated the electrophysiologic characteristics observed during LBBP using 6 modalities: right ventricular septal pacing (RVSP), intraventricular septal pacing (IVSP 1 and 2), LVS(e)P, nonselective LBBP (NSLBBP), and selective LBBP (SLBBP). RESULTS: Of the 97 patients, 87 (89.7%) met the criteria (abrupt change in paced QRS morphology with a transition from Qr to QR/qR in lead V1 and shortening of stimulus to V6 R-wave peak time [Stim-V6RWPT] of ≥ 10 ms with constant output while rather than after lead screwing) for nonselective left bundle branch (LBB) capture. Selective LBB capture was observed in 82 patients (84.5%). The Stim-V6RWPT of NSLBBP and SLBBP were significantly shorter than LVS(e)P (respectively, 67.1 ± 8.7 ms, 67.0 ± 9.3 ms, and 82.1 ± 10.9 ms). Stim-QRSend was the narrowest in IVSP2 (136.6 ± 15.2 ms) instead of NSLBBP (140.0 ± 17.1 ms). CONCLUSIONS: The uninterrupted pacing technique for differentiating LBBP from LVS(e)P in the same group of patients is feasible. Electrophysiologic evidence from our intrapatient-controlled study shows that LBBP and LVS(e)P differ in ventricular electrical synchronization.

Interesting phenomena during threshold testing of conduction system pacing: What is the mechanism?

BACKGROUND: Although the interest in conduction system pacing is increasing, the data on longitudinal dissociation in the literature is still limited. METHODS AND RESULTS: We performed left bundle branch (LBB) pacing on a patient with sick sinus syndrome and atrioventricular block. The transition of QRS morphology can be observed during the threshold testing. The main findings were different left ventricular activation times when selective LBB capture was performed at different outputs. CONCLUSIONS: This phenomenon may be due to the anatomical basis of longitudinal dissociation of the His-Purkinje system, which allows pacing stimulation at different thresholds to excite different portions of the conduction system.

Case report: Left bundle branch pacing guided by real-time monitoring of current of injury and electrocardiography.

Background: Left bundle branch (LBB) pacing (LBBP) has recently emerged as a physiological pacing mode. Current of injury (COI) can be used as the basis for electrode fixation position and detection of perforation. However, because the intermittent pacing method cannot monitor the changes in COI in real time, it cannot obtain information about the entire COI change process during implantation. Case summary: Left bundle branch pacing was achieved for treatment of atrioventricular block in a 76-year-old female. Uninterrupted electrocardiogram and electrogram were recorded on an electrophysiology system. In contrast to the interrupted pacing method, this continuous pacing and recording technique enables real-time monitoring of the change in ventricular COI and the paced QRS complex as the lead advances into the interventricular septum. During the entire screw-in process, the COI amplitude increased and then decreased gradually after reaching the peak, followed by a small but significant, rather than dramatic, decrease. Conclusion: This case report aims to demonstrate the clinical significance of changes in COI and QRS morphology for LBBP using real-time electrocardiographic monitoring and filtered and unfiltered electrograms when the lead is deployed using a continuous pacing technique. The technique could be used to confirm LBB capture and avoid perforation.

Epidemiological Trends in Alopecia Areata at the Global, Regional, and National Levels.

Background: No comprehensive studies have been published on the global burden of alopecia areata since 2010. Objective: We aimed to measure the global, regional, and national incidence of alopecia areata and disability-adjusted life-years (DALYs) by age, sex, and socio-demographic index (SDI) value from 1990 to 2019. Methods: Data were extracted from the Global Burden of Disease Study 2019. Estimated annual percentage changes (EAPCs) were calculated to quantify temporal trends in the age-standardized rates of alopecia areata incidence and DALYs. The correlations between EAPCs in the age-standardized rates and SDI values were also analyzed. Results: From 1990 to 2019, the alopecia areata incidence number and the associated number of DALYs increased globally by 49.14%, and 49.51%, respectively. The global age-standardized incidence rate decreased (EAPC, -0.13; 95% confidence interval [CI], -0.13 to -0.12) and the age-standardized DALY rate showed a downward trend (EAPC, -0.12; 95% CI, -0.13 to -0.11). The largest increases in the age-standardized incidence rate and age-standardized DALY rate were observed in Low SDI quintile and Western Sub-Saharan Africa regions. The regions with the greatest changes in the incidence of alopecia areata were Central Sub-Saharan Africa and Western Sub-Saharan Africa. The three countries with the largest increases in alopecia areata incidence from 1990 to 2019 were Kuwait (EAPC, 0.15), South Sudan (EAPC, 0.12), and Nigeria (EAPC, 0.11). The age-standardized incidence rate was higher in females than in males. Conclusion: Globally, both the age-standardized incidence rate and age-standardized DALY rate of alopecia areata showed decreasing trends. Future preventive strategies should focus on low-income countries, Central Sub-Saharan Africa, Western Sub-Saharan Africa, Kuwait, South Sudan, Nigeria.

Putamen Structure and Function in Familial Risk for Depression: A Multimodal Imaging Study.

BACKGROUND: The putamen has been implicated in depressive disorders, but how its structure and function increase depression risk is not clearly understood. Here, we examined how putamen volume, neuronal density, and mood-modulated functional activity relate to family history and prospective course of depression. METHODS: The study includes 115 second- and third-generation offspring at high or low risk for depression based on the presence or absence of major depressive disorder in the first generation. Offspring were followed longitudinally using semistructured clinical interviews blinded to their familial risk; putamen structure, neuronal integrity, and functional activation were indexed by structural magnetic resonance imaging (MRI), proton magnetic resonance spectroscopy (N-acetylaspartate/creatine ratio), and functional MRI activity modulated by valence and arousal components of a mood induction task, respectively. RESULTS: After adjusting for covariates, the high-risk individuals had lower putamen volume (standardized betas, ß-left = -0.17, ß-right = -0.15, ps = .002), N-acetylaspartate/creatine ratio (ß-left= -0.40, ß-right= -0.37, ps < .0001), and activation modulated by valence (ß-left = -0.22, ß-right = -0.27, ps < .05) than low-risk individuals. Volume differences were greater at younger ages, and N-acetylaspartate/creatine ratio differences were greater at older ages. Lower putamen volume also predicted major depressive disorder episodes up to 8 years after the scan (ß-left = -0.72, p = .013; ß-right = -0.83, p = .037). Magnetic resonance spectroscopy and task functional MRI measures were modestly correlated (0.27 ≤ r ≤ 0.33). CONCLUSIONS: Findings demonstrate abnormalities in putamen structure and function in individuals at high risk for major depressive disorder. Future studies should focus on this region as a potential biomarker for depressive illness, noting meanwhile that differences attributable to family history may peak at different ages based on which MRI modality is being used to assay them.

Interesting electrophysiological phenomenon during positioning of the lead deep inside the septum.

Left bundle branch pacing (LBBP) is a developing physiological pacing technique. Wu et al. proposed that direct LBB capture could be confirmed by recording retrograde His potential (PoReHis ) and mapping of the left conduction system potential. The transventricular-septal electrophysiological phenomena deserve further study. Here, we used a continuous uninterrupted pacing technique to confirm the LBB capture by dynamically observing changes in PoReHis and stimulus to left ventricular activation time.

High-pass filter settings and the role and mechanism of discrete ventricular electrograms in left bundle branch pacing.

Objective: The characteristics of discrete intracardiac electrogram (EGM) in selective left bundle branch (SLBB) pacing (SLBBP) have not been described in detail previously. This study aimed to examine the effect of different high-pass filter (HPF) settings on discrete local ventricular components in an intracardiac EGM and to analyze its possible mechanisms. Methods: This study included 144 patients with indications of permanent cardiac pacing. EGMs were collected at four different HPF settings (30, 60, 100, and 200 Hz) with a low-pass filter at 500 Hz, and their possible mechanisms were analyzed. Results: LBBP was successfully achieved in 91.0% (131/144) of patients. SLBBP was achieved in 123 patients. The occurrence rates of discrete local ventricular EGM were 16.7, 33.3, 72.9, and 85.4% for HPF settings of 30, 60, 100, and 200 Hz, respectively. The analysis of discrete EGM detection showed significant differences between the different HPF settings. By using the discrete local ventricular component and isoelectric interval as the SLBB capture golden standard, the results of EGMs revealed that the 30 Hz HPF has a sensitivity of 19% and specificity of 100%. The 60 Hz HPF had a sensitivity of 39% and a specificity of 100%. The 100 Hz HPF had a sensitivity of 85% and a specificity of 100%. The 200 Hz HPF had a sensitivity of 100% and specificity of 100%. Conclusion: An optimal HPF setting of 200 Hz is recommended for discrete local ventricular EGM detection. A discrete local ventricular EGM should exhibit an isoelectric interval. A steep deflection and high-frequency ventricular EGM morphology nearly identify an intrinsic EGM morphology.