Successful non-operative management of atrioesophageal fistula after combined therapy of catheter ablation and left atrial appendage closure for atrial fibrillation: A case report.

Atrioesophageal fistula (AEF) is a rare but devastating complication of radiofrequency ablation (RFCA) for atrial fibrillation (AF) and is associated with high mortality rates. Whereas most cases of AEF are treated by emergency surgical interventions, we report a case of paroxysmal AF with AEF after combined therapy of catheter ablation and percutaneous left atrial appendage closure (LAAC), which was treated successfuly without major surgery or esophageal stenting. He was presented 18 days after the procedure, suffering chest pain, fever, and a transient loss of consciousness. Computed tomography (CT) of the chest disclosed a small accumulation of air in the region of the left atrium adjacent to the esophagus, suggesting AEF. Supported by early aggressive antibiotic therapy, pericardial drainage and a fasting state with adequate parenteral nutrition, resulted in improvement of his condition with no recurrence of symptoms. Subsequent chest CT scans confirmed disappearance of the leaked air and the patient was discharged home 28 days after admission with no neurological compromise. Early detection, rapid treatment and constant awareness of potential fatal consequences are prerequisites for successful treatment of this complication and prevention of fatal outcome.

The value of postoperative HLA-DR expression and high mobility group box 1 level in predictive diagnosis of sepsis in percutaneous nephrolithotomy surgery.

OBJECTIVE: To analyze the value of postoperative human leukocyte antigen-DR (HLA-DR) expression and high mobility group box 1 (HMGB1) level in predictive diagnosis of postoperative sepsis for patients with percutaneous nephrolithotomy (PCNL) surgery. METHODS: The present prospective observational study included 387 patients with renal calculus who received PCNL surgery from January 2017 to October 2020 in our hospital. After exclusion criteria, 33 patients with sepsis and 78 patients with no sepsis remained. All patients received PCNL surgery. Sepsis definition is according to the third international consensus definitions for sepsis and septic shock (Sepsis-3). The data of the HMGB1, c-reactive protein (CRP), interleukin-6 (IL-6), procalcitonin (PCT) and HLA-DR expression were collected within admission and 24 h and 72 h after surgery. Postoperative HMGB1 levels and HLA-DR expression at 24 h and 72 h were respectively compared between the two groups using t test. ROC cure was used to analyze the value of postoperative HLA-DR expression and HMGB1 level in predictive diagnosis of sepsis. RESULTS: The positive rate of urine culture and the time of hospitalization time in patients with sepsis were significantly higher than those in patients with no sepsis. Sepsis group had higher levels of HMGB1 at post-24 h ((93.07 ± 11.37) ng/mL vs (75.41 ± 4.85) ng/mL), p < 0.05) and 72 h ((96.58 ± 12.12) ng/mL vs (81.16 ± 8.86) ng/mL), p < 0.05) than nosepsis group. Meanwhile, sepsis group had lower expression of HLA-DR at post-24 h ((50.01 ± 7.42) % vs (69.32 ± 10.58) %), p < 0.05) and 72 h ((54.85 ± 9.45) % vs (69.98 ± 11.00) %), p < 0.05) than non-sepsis group. ROC analysis showed that the HLA-DR expression at postoperative 24 h had highest predictive value in the diagnosis of sepsis, the AUC of HLA-DR was 0.934, cutoff value 56.19%, with sensitivity 89.7%, specificity 81.8%. CONCLUSION: Postoperative HLA-DR and HMGB1 can both be used as a predictive diagnosis of sepsis for patients with renal calculus received PCNL surgery. HighlightsSepsis group had higher levels of high mobility group box 1 at post-24 h and 72 h than nosepsis group.Sepsis group had lower expression of HLA-DR at post-24 h and 72 h than nosepsis group.Postoperative HLA-DR and HMGB1 can both be used as a predictive diagnosis of sepsis for patients with renal calculus received PCNL surgery.

Influence of the Hollowness and Size Distribution on the Magnetic Properties of Fe3O4 Nanospheres.

In this study, Fe3O4 nanospheres with different levels of hollowness were successfully prepared by the solvent thermal method. The synthesized Fe3O4 nanospheres were characterized by transmission electron microscopy, X-ray diffraction, and vibrating sample magnetometry, and Image-Pro software was used to analyze the hollowness of the Fe3O4 nanospheres for the first time. It was found that excess reactants could lead to the disappearance of the hollow structure of the Fe3O4 nanospheres, and the reason for this phenomenon was discussed as due to entropy increase theory. Furthermore, the influence of the hollowness and size distribution on the magnetic properties of the Fe3O4 nanospheres was evaluated. The magnetic properties of a Fe3O4 nanosphere with a hollowness of 10.48% showed a relatively high saturation magnetization of 103 emu/g and a rather low coercivity (54 Oe). The as-prepared Fe3O4 nanospheres are expected to be useful in a wide range of fields such as drug-delivery and energy applications.

Relationship among adiponectin, insulin resistance and atherosclerosis in non-diabetic hypertensive patients and healthy adults.

Adiponectin, which is secreted specifically by adipose tissue, has been shown to have anti-atherogenic and anti-inflammatory effects and to improve insulin resistance (IR). The aim of this study was to determine the correlations among adiponectin, IR and atherosclerosis in non-diabetic hypertensive patients and healthy volunteers. In this case control study, we collected complete demographic data from and measured several laboratory parameters in all enrolled subjects. The homeostasis model of assessment for insulin resistance (HOMA-IR) was calculated as an insulin sensitivity index. The atherogenic index of plasma (AIP), which is calculated as log (triglyceride (TG)/high-density lipoprotein cholesterol (HDL-C)), was a significant predictor of atherosclerosis and was a better predictor of atherosclerosis than low-density lipoprotein cholesterol (LDL-C). Plasma adiponectin, interleukin (IL)-6, monocyte chemoattractant protein-1 (MCP-1) and matrix metalloprotein-9 (MMP-9) concentrations were determined using enzyme-linked immunosorbent assay (ELISA). All data were analyzed using Statistical Product and Service Solutions for Windows (SPSS) 13.0 software. A total of 309 participants were enrolled in the study. Hypertensive patients with IR (n = 93) displayed significantly higher HOMA-IR values and AIPs and lower adiponectin levels than hypertensive patients without IR (n = 121) and healthy adults (n = 95) (P < 0.05). Furthermore, circulating IL-6, MCP-1 and MMP-9 concentrations differed significantly between hypertensive patients and healthy adults (P < 0.05). Additionally, adiponectin levels were found to be inversely correlated with IL-6, MCP-1, and MMP-9 levels; HOMA-IR values; and AIPs in the clinical study. HOMA-IR values and adiponectin and creatinine (Cr) concentrations remained independently associated with AIPs in all participants after adjustment for confounders via multivariate linear regression. Low adiponectin levels are positively correlated with decreased insulin sensitivity, increased pro-inflammatory cytokine production and worsening atherosclerosis in hypertensive patients and healthy adults.

Encapsulating Fe3O4 into calcium alginate coated chitosan hydrochloride hydrogel beads for removal of Cu (II) and U (VI) from aqueous solutions.

The aim of this work was to study the removal of Cu (II) and U (VI) ions from aqueous solutions by encapsulating magnetic Fe3O4 nanoparticles into calcium alginate coated chitosan hydrochloride (CCM) hydrogel beads. ATR-FTIR and XRD analysis data indicated that the CCM composites were successfully prepared. SEM images and EDX spectra showed that Cu2+ and UO22+ ions were adhered onto sorbents. Adsorption properties for removal of both copper and uranium ions under various experimental conditions were investigated. Kinetic data and sorption equilibrium isotherms were also conducted in batch process. The sorption kinetic analysis revealed that sorption of Cu (II) and U (VI) followed the pseudo-second-order model well and exhibited 3-stage intraparticle diffusion model during the whole sorption process. Equilibrium data were best described by Langmuir model, and the CCM composite hydrogel beads showed the estimated maximum adsorption capacity 143.276mg/g and 392.692mg/g for Cu (II) and U (VI), respectively. The CCM adsorbent exhibited excellent reusability for five cycles use without significant changes in the adsorption capacity and structural stability. The results demonstrated that CCM can be an effective and promising sorbent for Cu (II) and U (VI) ions in wastewater.

Graphene oxide encapsulated polyvinyl alcohol/sodium alginate hydrogel microspheres for Cu (II) and U (VI) removal.

In this work, a novel sodium alginate (SA)/polyvinyl alcohol (PVA)/graphene oxide (GO) hydrogel microspheres were prepared by a simple method. Sodium alginate was physically crosslinked by Ca2+; GO was encapsulated into the composite to strengthen the hydrogels; PVA played a significant role in well dispersing of GO in SA. The SA/PVA/GO (SPG) hydrogels were employed as an efficient adsorbent for removal of Cu (II) and U (VI) from aqueous solution. Batch experiments with the subject of the pH, initial metal ion concentration, competing ions and contact time were investigated. Structure characterization was successfully conducted by FTIR, SEM, EDX, BET and XPS. Furthermore, the sorption kinetics of Cu2+ and UO22+ followed pseudo-second order model and exhibited 3-stage intraparticle diffusion model. Equilibrium data were best described by Langmuir model and the obtained maximum adsorption capacities of SPG hydrogel microspheres for Cu2+ and UO22+ were 247.16 and 403.78 mg/g, respectively. The difference in adsorption capacity can be confirmed by the percentage of elements in EDX spectra and the intension of peak of elements in XPS spectra. The SPG sorbent exhibited excellent reusability after 5 adsorption-desorption cycles. All results suggested that the prepared adsorbents could be considered as effective and promising materials for removal of Cu (II) and U (VI) in wastewater.

Online Streaming Video Super-Resolution With Convolutional Look-Up Table.

Online video streaming has fundamental limitations on the transmission bandwidth and computational capacity and super-resolution is a promising potential solution. However, applying existing video super-resolution methods to online streaming is non-trivial. Existing video codecs and streaming protocols (e.g., WebRTC) dynamically change the video quality both spatially and temporally, which leads to diverse and dynamic degradations. Furthermore, online streaming has a strict requirement for latency that most existing methods are less applicable. As a result, this paper focuses on the rarely exploited problem setting of online streaming video super resolution. To facilitate the research on this problem, a new benchmark dataset named LDV-WebRTC is constructed based on a real-world online streaming system. Leveraging the new benchmark dataset, we propose a novel method specifically for online video streaming, which contains a convolution and Look-Up Table (LUT) hybrid model to achieve better performance-latency trade-off. To tackle the changing degradations, we propose a mixture-of-expert-LUT module, where a set of LUT specialized in different degradations are built and adaptively combined to handle different degradations. Experiments show our method achieves 720P video SR around 100 FPS, while significantly outperforms existing LUT-based methods and offers competitive performance compared to efficient CNN-based methods. Code is available at https://github.com/quzefan/ConvLUT.

Evaluation of teaching method for fluid mechanics course in engineering education.

The professional technology training of student is the important objective of engineering education, which could present the specialized ability in the future. This task is conducted to evaluation of teaching methods for fluid mechanics course in the mechanical engineering. With the teaching practice, the advantage of teaching method is found, and the teaching quality can be revealed by the scores of integrated test. The improvement of teaching quality is contribute the development of social. According to the self-assessment, the effects of teaching method on the professional course is revealed.•The diversified teaching method is advantage to the understanding of theory and knowledge of application.•The practical training is suitable to develop the inner potential and innovation of different students.•The method allows the investigation of teaching method evaluation for the other courses with practicality.

Vapor-Liquid-Solid Growth of Site-Controlled Monolayer MoS2 Films Via Pressure-Induc ed Supercritical Phase Nucleation.

In this study, a novel pressure-induced supercritical phase nucleation method is proposed to synthesize monolayer MoS2 films, which is promoter free and can avoid contamination of films derived from these heterogeneous promoters in most of the existing techniques. The low-crystallinity and size-controlled MoO2(acac)2 particles are recrystallized on the substrate via the pressure-sensitive solvent capacity of supercritical CO2 and these particles are used as growth sites. The size of single-crystal MoS2 on the substrate is found to be dependent on the wetting area of the pyrolyzed precursor droplets (MoO2) on the surface, and the formation of continuous films with high coverage is mainly controlled by the coalescence of MoO2 droplets. It is enhanced by the increase of the nucleation site density, which can be adjusted by the supersaturation of the supercritical fluid solution. Our findings pave a new way for the controllable growth of MoS2 and other two-dimensional materials and provide sufficient and valuable evidence for vapor-liquid-solid growth.

Systemic therapies for metastatic renal cell carcinoma in the second-line setting: A systematic review and network meta-analysis.

OBJECTIVES: To perform a systematic review and network meta-analysis to compare the survival benefit and safety profile of current available second-line treatment options of metastatic renal cell carcinomav. METHODS: PubMed, EMBASE, Web of Science, and Cochrane Library were systematically researched for eligible articles which were published before July 20, 2021. Studies comparing overall/progression free survival (OS/PFS), objective response rate (ORR), and/or adverse events (AEs) in patients with metastatic renal cell carcinomav were included. RESULTS: Nine trials (with 4911 patients) were finally included for final network meta-analysis. Cabozantinib, lenvatinib, and lenvatinib plus everolimus were associated with significantly better PFS, OS, and ORR compared with everolimus, and lenvatinib plus everolimus emerged as the best option. As for grade 3 to 4 AEs, nivolumab showed significantly lower risk of AEs compared with everolimus. Other included treatments were associated with significantly increased risk of AEs. When comprehensively assessed the efficacy and safety of included treatments based on the ranking analysis of PFS, ORR, and grade 3 to 4 AEs, lenvatinib plus everolimus, cabozantinib, and nivolumab showed superior efficacy over other treatments, with relatively lower risk of grade 3 to 4 AEs. CONCLUSIONS: Among all included therapies, Lenvatinib plus everolimus was identified as the most effective treatment approach, with the best PFS, OS, and ORR. nivolumab was associated with decreased incidence of grade 3 to 4 AEs among included treatment therapies. When comprehensively evaluated the efficacy and safety of included treatment options, lenvatinib plus everolimus, cabozantinb, and nivolumab were associated with better survival benefits and lower risk of AEs. Future studies should focus on the direct comparison of different second-line treatment in real-world populations.

Predictive values of the SOFA score and procalcitonin for septic shock after percutaneous nephrolithotomy.

To investigate the value of combination of the Sequential Organ Failure Assessment (SOFA) score and procalcitonin (PCT) for prediction of septic shock after percutaneous nephrolithotomy (PCNL). A total of 1328 patients receiving PCNL for renal calculi were allocated into control group (without septic shock) and septic shock group, and related data were retrospectively collected. Univariate analysis was firstly performed, and the variables with two sided P < 0.10 were then included in logistic regression analysis to determine independent risk factors. Receiver operating characteristic (ROC) curve was utilized to evaluate the predictive values. Area under curve (AUC) was compared using Z test. Postoperative septic shock was developed in 61 patients (4.6%) and not developed in 1267 patients (95.3%). Multivariate analysis demonstrated that SOFA score (OR: 1.316, 95% CI 1.125-1.922), PCT (OR: 1.205, 95% CI 1.071-1.696) and operative time (OR: 1.108, 95% CI 1.032-1.441) were independent risk factors for septic shock with adjustment for sex, history of urolithiasis surgery, positive history of urine culture and history of PCNL. The ROC curves demonstrated that the AUCs of SOFA score and PCT for predicting septic shock after PCNL were 0.896 (95% CI 0.866-0.927) and 0.792 (95% CI 0.744-0.839), respectively. The AUC of their combination was 0.971 (95% CI 0.949-0.990), which was higher than those of individual predictions (vs 0.896, Z = 4.086, P < 0.001; vs 0.792, Z = 6.983, P < 0.001). Both the SOFA score and PCT could be applied in predicting septic shock after PCNL, and their combination could further elevate the diagnostic ability.

[Relationship of histidine auxotrophy of Acidovorax citrulli with pathogenicity].

UNLABELLED: Acidovorax citrulli (Ac) is an important bacterium that occurs in watermelon, melon and other cucurbits. It mainly damages watermelon and melon, and can cause leaf blight, fruit rot, and even mortality. OBJECTIVE: To verify the relationship between defects in the synthesis of histidine and the pathogenicity of Ac. METHODS: We generated a transposon (Tn5) mutant library on the background of strain xjl12 of Ac. Then we used subclone technology to identify the gene. RESULTS: The mutant could not elicit the hypersensitive response (HR) in nonhost tobacco, and its virulence was reduced. It is impaired in hisC, which encodes the protein histidinolphosphate aminotransferase. The other three genes (hisA, hisB and hisD) involved in the process of histidine synthesis were also studied. These mutants could not elicit the hypersensitive response (HR) in nonhost tobacco; their virulence was reduced significantly and disease symptoms caused by mutants were delayed for 48 hours when compared to the wild type strain. By adding exogenous histidine, pathogenicity of the mutants was restored. CONCLUSION: The change of the characteristics of the mutants was directly related to the synthesis of histidine.

[Electrophysiologic characteristics of Ito in myocytes from cardiac Koch triangle].

OBJECTIVE: To explore the electrophysiologic characteristics of Ito in myocytes from cardiac Koch triangle. METHODS: Patch clamp technique was employed to investigate the I-V and D-V relation, steady-state activation and inactivation kinetics of Ito from myocytes in Koch triangle of rabbit hearts. RESULTS: (1) The maximum peak current (pA) and peak current density (pA/pF) at +20 mV in PC (pacing cell), TC (transitonal cell) alpha,beta, AC (atrial cell) and PL (purkinje-like cell) cells were different from each other (P < 0. 05); The cells also had different current density (P < 0.05) except between TCalpha, TCbeta and PL cells (P > 0.05). (2) The half activation potential (V(mIto1/2), mV) of steady state activation among PC, TCalpha, TCbeta, AC and PL were significantly different (P < 0.05); The paired comparison between TCalpha and TCbeta, AC and PL, and TCbeta and PC showed significant difference (P < 0.05); but the differences between TCa and PC, TCbeta and AC, and TCbeta and PL were not significant (P > 0.05). (3) The half inactivation potential (V5(hIto1/2), mV) of steady state inactivation between TCalpha and PC, TCa and PL, TCbeta and PC, and TCbeta and PL demonstrated significant differences(P < 0.05). The differences of K(hIto) between TCalpha and TCbeta, PC and PL, TCbeta and PC, and AC and PL were significant (P < 0.05). CONCLUSIONS: Ito of cardiac cells from Koch triangle in rabbit hearts are heterogeneous, but relatively specified and distributed in different groups.

NLRP3 inflammasome promotes diabetes-induced endothelial inflammation and atherosclerosis.

BACKGROUND: NLRP3 inflammasome can be activated by high glucose and links inflammation and metabolic disease. This study aimed to investigate the role of NLRP3 inflammasome in hyperglycemia-induced endothelial inflammation and diabetic atherosclerosis. METHODS: NLRP3 levels in peripheral blood mononuclear cell (PBMC) and plasma IL-1ß level were measured in diabetes patients. The activation of NLPR3 was detected in diabetic ApoE-/- mice and human umbilical vein endothelial cells (HUVECs). RESULTS: Compared with healthy controls, NLRP3 expression levels in PBMC and plasma IL-1ß level were significantly higher in diabetes patients but considerably decreased after lifestyle interventions and medicine. Moreover, carotid atherosclerosis was significantly related to plasma IL-1ß level in diabetes patients. In diabetic atherosclerosis mouse model, NLRP3 knockdown suppressed NLRP3 inflammasome activation, inhibited the expression of adhesion molecules ICAM-1 and VCAM-1 in intima, reduced atherosclerosis and stabilized atherosclerotic plaque. In vitro, the expression of NLRP3 inflammasome components and the secretion of IL-1ß were augmented by high glucose in HUVECs. Moreover, either high glucose or IL-1ß promoted the expression of adhesion molecules, which were suppressed by NLRP3 knockdown or IL-1ß receptor antagonist. CONCLUSION: These findings provide novel insights into pathological mechanisms of diabetic atherosclerosis and have potential therapeutic implications for cardiovascular complications in diabetes.

A facile soft template method to synthesize hollow carbon and MnO x composite particles for effective methylene blue degradation.

Hollow carbon and MnO x composite particles (HC-Mn) were fabricated by using polyacrylic acid (PAA) and Mn ion co-assembled colloids as the soft template and resorcinol formaldehyde resin (RF) as the carbon source. The formation process was well studied and a plausible formation mechanism was proposed. The Mn ions played two key roles in the synthesis: first, they promoted the aggregation of the PAA molecules, thus forming the PAA-Mn colloids in solution with high water content, which were suitable for the subsequent RF coating. Secondly, considerable Mn ions were retained after template removal, which were transformed into MnO x particles simultaneously during carbonization. This approach was facile and effective and the as-prepared HC-Mn showed superior catalytic activity toward methylene blue (MB) degradation.

3-Bromo-4,5-Dihydroxybenzaldehyde Protects Against Myocardial Ischemia and Reperfusion Injury Through the Akt-PGC1α-Sirt3 Pathway.

Natural marine products are useful candidates for the treatment of oxidative and inflammatory diseases, including myocardial ischemia. 3-bromo-4,5 - dihydroxybenzaldehyde (BDB), a natural bromophenol isolated from marine red algae, has been shown to display anti-microbial, anti-oxidative, anti-cancer, anti-inflammatory, and free radical scavenging activities. In this study, the potential protective effects of BDB against myocardial ischemia and reperfusion (IR) injury was investigated in an in vitro model mimicked by oxygen and glucose deprivation (OGD) in cardiomyocytes and in an in vivo model induced by coronary artery ligation in rats. The results showed that BDB attenuated the OGD-induced cytotoxicity in a dose-dependent manner, with no toxic effect when treated alone. BDB significantly decreased apoptosis and the cleavage of caspase-3 after OGD. We found that OGD-induced oxidative stress, as evidenced by increases of reactive oxygen species (ROS) and lipid peroxidation, as well as mitochondrial dysfunction, as measured by mitochondrial reporter gene, cytochrome c release and ATP synthesis, were markedly attenuated by BDB treatment. In addition, BDB increased the enzymatic activities of mitochondrial antioxidant enzymes, including IDH2, GSH-Px and SOD2. Western blot analysis showed that BDB increased Akt phosphorylation and upregulated the expression of Sirt3 and PGC1α after OGD. Furthermore, BDB-induced protection in cardiomyocytes was partially reversed by the Akt inhibitor and downregulation of PGC1α. BDB also attenuated myocardial contractile dysfunction and activated the Akt-PGC1α-Sirt3 pathway in vivo. All these data suggest that BDB protects against myocardial IR injury through activating the Akt-PGC1α-Sirt3 pathway.

Investigation of the Quasi-Brittle Failure of Alashan Granite Viewed from Laboratory Experiments and Grain-Based Discrete Element Modeling.

Granite is a typical crystalline material, often used as a building material, but also a candidate host rock for the repository of high-level radioactive waste. The petrographic texture-including mineral constituents, grain shape, size, and distribution-controls the fracture initiation, propagation, and coalescence within granitic rocks. In this paper, experimental laboratory tests and numerical simulations of a grain-based approach in two-dimensional Particle Flow Code (PFC2D) were conducted on the mechanical strength and failure behavior of Alashan granite, in which the grain-like structure of granitic rock was considered. The microparameters for simulating Alashan granite were calibrated based on real laboratory strength values and strain-stress curves. The unconfined uniaxial compressive test and Brazilian indirect tensile test were performed using a grain-based approach to examine and discuss the influence of mineral grain size and distribution on the strength and patterns of microcracks in granitic rocks. The results show it is possible to reproduce the uniaxial compressive strength (UCS) and uniaxial tensile strength (UTS) of Alashan granite using the grain-based approach in PFC2D, and the average mineral size has a positive relationship with the UCS and UTS. During the modeling, most of the generated microcracks were tensile cracks. Moreover, the ratio of the different types of generated microcracks is related to the average grain size. When the average grain size in numerical models is increased, the ratio of the number of intragrain tensile cracks to the number of intergrain tensile cracks increases, and the UCS of rock samples also increases with this ratio. However, the variation in grain size distribution does not have a significant influence on the likelihood of generated microcracks.

Morphological and electrophysiological properties of single myocardial cells from Koch triangle of rabbit heart.

BACKGROUND: The morphological and electrophysiological characteristics of cardiac cells in Koch triangle are still disputed. We studied the appearance and electrical properties of these diverse myocytes to elucidate their complex electrophysiological phenomena. METHODS: Experiments were conducted using cooled charge coupling device (CCD) system and whole cell, patch clamp technique to determine the morphology, action potential and sodium current density of single viable myocytes enzymatically isolated from the Koch triangle of rabbit hearts. RESULTS: Morphologically, cardiac cells in shape of spider, tiny spindle, slender spindle, rod and strip were observed in percentage of 3.0 +/- 0.3, 35.0 +/- 5.0, 15.0 +/- 2.0, 40.0 +/- 5.0 and 6.0 +/- 0.7 respectively. The cellular dimensions and capacitance gradually increased in the above order (all P < 0.05). Electrophysiologically, action potential configurations recorded from them were similar respectively to nodal (N), atrial nodal (AN), nodal Hisian (NH), atrial (A) and Hisian like potentials obtained from the intact atrioventricular nodal preparations. Diastolic depolarization appeared in all myocytes except for rod cells. Sodium current density increased in the order of tiny spindle, strip, rod, slender spindle cell (all P < 0.05), but could not be detected in spider-shaped cells. Linear regression analysis revealed that membrane capacitance was correlated negatively to the rate of diastolic depolarization r = -0.70, P < 0.001, but positively to maximum depolarization potential, amplitude of action potential, upstroke velocity and maximum peak value of sodium current density r = 0.84, 0.80, 0.87 and 0.75, respectively; all P < 0.001. CONCLUSIONS: The results demonstrated that spider-shaped, spindle, rod and strip cells in Koch triangle might correspond to pacemaking, transitional, atrial and Purkinje like cells, respectively. Furthermore, tiny spindle and slender spindle cells were referred to transitional cell alpha (TCalpha) and beta (TCbeta) accordingly considering their distinctive electrical properties. Different myocytes with diverse electrical properties constituted the infrastructure of sophisticated electrophysiological phenomena in Koch triangle. In view of the prominent percentage and electrical properties, tiny spindle and slender spindle cells were presumed to play important roles.