Non-Abelian Braiding of Topological Edge Bands.

Braiding is a geometric concept that manifests itself in a variety of scientific contexts from biology to physics, and has been employed to classify bulk band topology in topological materials. Topological edge states can also form braiding structures, as demonstrated recently in a type of topological insulators known as Möbius insulators, whose topological edge states form two braided bands exhibiting a Möbius twist. While the formation of Möbius twist is inspiring, it belongs to the simple Abelian braid group B_{2}. The most fascinating features about topological braids rely on the non-Abelianness in the higher-order braid group B_{N} (N≥3), which necessitates multiple edge bands, but so far it has not been discussed. Here, based on the gauge enriched symmetry, we develop a scheme to realize non-Abelian braiding of multiple topological edge bands. We propose tight-binding models of topological insulators that are able to generate topological edge states forming non-Abelian braiding structures. Experimental demonstrations are conducted in two acoustic crystals, which carry three and four braided acoustic edge bands, respectively. The observed braiding structure can correspond to the topological winding in the complex eigenvalue space of projective translation operator, akin to the previously established point-gap winding topology in the bulk of the Hatano-Nelson model. Our Letter also constitutes the realization of non-Abelian braiding topology on an actual crystal platform, but not based on the "virtual" synthetic dimensions.

[Evaluation of disinfection effect of high-energy pulse ultraviolet disinfection equipment in medical institution settings].

Objective: To evaluate the disinfection effect of high-energy pulse ultraviolet disinfection equipment in medical institution settings. Methods: The disinfection effect was evaluated through field tests and laboratory tests. Among them, 135 high-frequency contact points were selected from nine departments in the field test. Samples were collected before and after disinfection, and the disinfection effects of 75% alcohol wipes wiping disinfection, high-energy pulse ultraviolet disinfection robot disinfection and high-energy pulse ultraviolet handheld disinfection instrument were compared. In the laboratory test, 30 infected areas of the simulated test table were exposed to vertical ultraviolet irradiation and the bacterial-killing rate before and after disinfection was calculated. Results: In the field test, the bacteria-killing rates of 75% alcohol wipes, high-energy pulse ultraviolet disinfection robot and high-energy pulse ultraviolet handheld disinfection instrument were 94.99%, 91.53% and 95.94%, respectively, and the difference was statistically significant. The disinfection effect of the high-energy pulse ultraviolet handheld disinfection instrument was better than that of the high-energy pulse ultraviolet disinfection robot (P values <0.05). In the laboratory test, the killing log value of Staphylococcus aureus and Escherichia coli on the carrier were both greater than 3.00. In the simulated field test, the killing log value of Staphylococcus aureus on the surface samples were 4.99. Conclusion: Both the high-energy pulse ultraviolet handheld disinfection instrument and the high-energy pulse ultraviolet disinfection robot have good disinfection effects, which are similar to the disinfection effects of conventional 75% alcohol wipes.

[Clinical characteristics and follow-up analysis of 63 cases of silicosis complicated with cavity-pulmonary tuberculosis].

Objective: To investigate the clinical characteristics and prognosis of silicosis complicated with cavity-pulmonary tuberculosis. Methods: The clinical data of 63 patients with silicosis complicated with cavity-pulmonary tuberculosis (group A) and silicosis patients (group B) admitted to Yantaishan Hospital from July 2018 to July 2022 were collected and analyzed. Results: Patients in group A were all male, and the common symptoms were cough, expectoration, chest tightness, shortness of breath, and hemoptysis. CT cavity lesions involving the lung, often occurs in the lung after the tip section, after the back section and basal segment, thick-walled cavity, may be accompanied by satellite lesions, endobronchial spread focal, pneumothorax, pleural effusion, etc. 1225 cases of group B patients haemoptysis of 59 patients, cavity in 3 patients, haemoptysis and/or cavity rate was lower than that in group A, the difference was statistically significant (P<0.05) . In group A, CT reexamination 6-24 months after anti-tuberculosis treatment showed that 52 cases (82.5%) had cavity reduction/healing, 8 cases (12.7%) had recurrence, and 3 cases (4.8%) had damaged lung (2 died) . Conclusion: Silicosis patients with hemoptysis and/or CT in cavity should be more vigilant about combined tuberculosis, anti-tuberculosis treatment and/or dynamic CT follow-up helps laboratory diagnosis negative patients.

General Theory of Momentum-Space Nonsymmorphic Symmetry.

As a fundamental concept of all crystals, space groups are partitioned into symmorphic groups and nonsymmorphic groups. Each nonsymmorphic group contains glide reflections or screw rotations with fractional lattice translations, which are absent in symmorphic groups. Although nonsymmorphic groups ubiquitously exist on real-space lattices, on the reciprocal lattices in momentum space, the ordinary theory only allows symmorphic groups. In this work, we develop a novel theory for momentum-space nonsymmorphic space groups (k-NSGs), utilizing the projective representations of space groups. The theory is quite general: Given any k-NSGs in any dimensions, it can identify the real-space symmorphic space groups (r-SSGs) and construct the corresponding projective representation of the r-SSG that leads to the k-NSG. To demonstrate the broad applicability of our theory, we show these projective representations and therefore all k-NSGs can be realized by gauge fluxes over real-space lattices. Our work fundamentally extends the framework of crystal symmetry, and therefore can accordingly extend any theory based on crystal symmetry, for instance, the classification crystalline topological phases.

Making Topologically Trivial Non-Hermitian Systems Nontrivial via Gauge Fields.

Non-Hermiticity significantly enriches the concepts of symmetry and topology in physics. Particularly, non-Hermiticity gives rise to the ramified symmetries, where the non-Hermitian Hamiltonian H is transformed to H^{†}. For time-reversal (T) and sublattice symmetries, there are six ramified symmetry classes leading to novel topological classifications with various non-Hermitian skin effects. As artificial crystals are the main experimental platforms for non-Hermitian physics, there exists the symmetry barrier for realizing topological physics in the six ramified symmetry classes: while artificial crystals are in spinless classes with T^{2}=1, nontrivial classifications dominantly appear in spinful classes with T^{2}=-1. Here, we present a general mechanism to cross the symmetry barrier. With an internal parity symmetry P, the square of the combination T[over ˜]=PT can be modified by appropriate gauge fluxes. Using the general mechanism, we systematically construct spinless models for all non-Hermitian spinful topological phases in one and two dimensions, which are experimentally realizable. Our Letter suggests that gauge structures may significantly enrich non-Hermitian physics at the fundamental level.

Second-Order Real Nodal-Line Semimetal in Three-Dimensional Graphdiyne.

Real topological phases featuring real Chern numbers and second-order boundary modes have been a focus of current research, but finding their material realization remains a challenge. Here, based on first-principles calculations and theoretical analysis, we reveal the already experimentally synthesized three-dimensional (3D) graphdiyne as the first realistic example of the recently proposed second-order real nodal-line semimetal. We show that the material hosts a pair of real nodal rings, each protected by two topological charges: a real Chern number and a 1D winding number. The two charges generate distinct topological boundary modes at distinct boundaries. The real Chern number leads to a pair of hinge Fermi arcs, whereas the winding number protects a double drumhead surface bands. We develop a low-energy model for 3D graphdiyne which captures the essential topological physics. Experimental aspects and possible topological transition to a 3D real Chern insulator phase are discussed.

Projectively Enriched Symmetry and Topology in Acoustic Crystals.

Symmetry plays a key role in modern physics, as manifested in the revolutionary topological classification of matter in the past decade. So far, we seem to have a complete theory of topological phases from internal symmetries as well as crystallographic symmetry groups. However, an intrinsic element, i.e., the gauge symmetry in physical systems, has been overlooked in the current framework. Here, we show that the algebraic structure of crystal symmetries can be projectively enriched due to the gauge symmetry, which subsequently gives rise to new topological physics never witnessed under ordinary symmetries. We demonstrate the idea by theoretical analysis, numerical simulation, and experimental realization of a topological acoustic lattice with projective translation symmetries under a Z_{2} gauge field, which exhibits unique features of rich topologies, including a single Dirac point, Möbius topological insulator, and graphenelike semimetal phases on a rectangular lattice. Our work reveals the impact when gauge and crystal symmetries meet together with topology and opens the door to a vast unexplored land of topological states by projective symmetries.

[Clinicopathological features and BRAF V600E and MYD88 L265P mutation status of nodal marginal zone lymphoma].

Objective: To investigate the clinicopathological features as well as BRAF V600E and MYD88 L265P mutation status of nodal marginal zone B cell lymphoma (NMZL). Methods: Thirty-two cases of NMZL were diagnosed from September 2009 to February 2021 at the Henan Provincial People's Hospital and Peking University School of Basic Medical Sciences. The clinicopathologic characteristics were obtained and analyzed. BRAF V600E and MYD88 L265P mutation status were identified using PCR and Sanger sequencing, respectively. Results: There were 20 males and 12 females patients with a median age of 69 years (ranging 36-82 years). The most prevalent clinical manifestation was multiple lymph nodes enlargement in head and neck (22/32, 68.8%), followed by inguinal (12/32, 37.5%), axillary (11/32, 34.4%), mediastinum (5/32, 15.6%) and retroperitoneal lymph nodes (4/32, 12.5%). Most of the patients were in Ann Arbor stage Ⅰ/Ⅱ (21 cases). The morphologic features included diffuse (24/32, 75.0%), nodular (5/32, 15.6%), interfollicular (2/32,6.3%) and perifollicular (1/32,3.1%) types. The tumor cells showed monocyte-like, centrocyte-like, small lymphocyte-like and plasma cell-like differentiation. Immunophenotyping revealed diffuse expression of CD20 in all tumor cells, whereas CD43 (11/32, 34.4%), bcl-2 (20/32, 62.5%), MNDA (13/32, 40.6%) and CD5 (2/32, 6.3%) were partially expressed. Ki-67 proliferation index varied from 10% to 40%. BRAF V600E mutation was found in two cases (2/32, 6.3%), but MYD88 L265P mutation was not detected. Eighteen patients survived and three died at the end of follow-up period which ranged 6 to 110 months. Conclusions: The morphologic features of NMZL varies across individuals, it should be differentiated from various B-cell lymphomas; however immunological biomarkers with high specificity for NMZL are still lacking. No MYD88 L265P mutation is found in NMZL. Some cases may harbor BRAF V600E mutation and yet the prevalence remains indeterminate; further researches are warranted.

Index Theorem on Chiral Landau Bands for Topological Fermions.

Topological fermions as excitations from multidegenerate Fermi points have been attracting increasing interest in condensed matter physics. They are characterized by topological charges, and magnetic fields are usually applied in experiments for their detection. Here we present an index theorem that reveals the intrinsic connection between the topological charge of a Fermi point and the in-gap modes in the Landau band structure. The proof is based on mapping fermions under magnetic fields to a topological insulator whose topological number is exactly the topological charge of the Fermi point. Our Letter lays a solid foundation for the study of intriguing magnetoresponse effects of topological fermions.

Emergent Kondo Behavior from Gauge Fluctuations in Spin Liquids.

The Kondo effect is a prominent quantum phenomenon describing the many-body screening of a local magnetic impurity. Here, we reveal a new type of nonmagnetic Kondo behavior generated by gauge fluctuations in strongly correlated baths. We show that a nonmagnetic bond defect not only introduces the potential scattering but also locally enhances the gauge fluctuations. The local gauge fluctuations further mediate a pseudospin exchange interaction that produces an asymmetric Kondo fixed point in low energy. The gauge-fluctuation-induced Kondo phenomena do not exhibit the characteristic resistivity behavior of the conventional Kondo effect, but display a nonmonotonous temperature dependence of thermal conductivity as well as an anisotropic pseudospin correlation. Moreover, with its origin from gauge fluctuations, the Kondo features can be regarded as promising indicators for identifying quantum spin liquids. Our work advances fundamental knowledge of novel Kondo phenomena in strongly correlated systems, which have no counterparts in thermal baths within the single-particle description.

Switching Spinless and Spinful Topological Phases with Projective PT Symmetry.

A fundamental dichotomous classification for all physical systems is according to whether they are spinless or spinful. This is especially crucial for the study of symmetry-protected topological phases, as the two classes have distinct symmetry algebra. As a prominent example, the spacetime inversion symmetry PT satisfies (PT)^{2}=±1 for spinless/spinful systems, and each class features unique topological phases. Here, we reveal a possibility to switch the two fundamental classes via Z_{2} projective representations. For PT symmetry, this occurs when P inverses the gauge transformation needed to recover the original Z_{2} gauge connections under P. As a result, we can achieve topological phases originally unique for spinful systems in a spinless system, and vice versa. We explicitly demonstrate the claimed mechanism with several concrete models, such as Kramers degenerate bands and Kramers Majorana boundary modes in spinless systems, and real topological phases in spinful systems. Possible experimental realization of these models is discussed. Our work breaks a fundamental limitation on topological phases and opens an unprecedented possibility to realize intriguing topological phases in previously impossible systems.

Gauge-Field Extended k·p Method and Novel Topological Phases.

Although topological artificial systems, like acoustic and photonic crystals and cold atoms in optical lattices were initially motivated by simulating topological phases of electronic systems, they have their own unique features such as the spinless time-reversal symmetry and tunable Z_{2} gauge fields. Hence, it is fundamentally important to explore new topological phases based on these features. Here, we point out that the Z_{2} gauge field leads to two fundamental modifications of the conventional k·p method: (i) The little co-group must include the translations with nontrivial algebraic relations. (ii) The algebraic relations of the little co-group are projectively represented. These give rise to higher-dimensional irreducible representations and therefore highly degenerate Fermi points. Breaking the primitive translations can transform the Fermi points to interesting topological phases. We demonstrate our theory by two models: a rectangular π-flux model exhibiting graphenelike semimetal phases, and a graphite model with interlayer π flux that realizes the real second-order nodal-line semimetal phase with hinge helical modes. Their physical realizations with a general bright-dark mechanism are discussed. Our finding opens a new direction to explore novel topological phases unique to crystalline systems with gauge fields and establishes the approach to analyze these phases.

[Breast ultrasound optimization process analysis based on breast cancer screening for 1 501 753 rural women in China].

Objective: To evaluate the effectiveness and quality of ultrasound-based (BUS) process optimization in breast cancer screening. Methods: The program collected the first to fourth quarterly breast cancer screening statistic data and case report data from 30 provinces, autonomous regions and municipalities in 2015 by the online report system of national key service program of women and children's public health. The call rate, mammography (MG) subsequent screen rate, biopsy rate, detection rate, early diagnosis rate, carcinoma in situ rate, missing detection rate, false positive rate and positive predictive value (PPV) of breast cancer were calculated. Results: A total of 1 501 753 rural women attended the BUS process optimization screening. The nationwide recall rate was 3.01%(45 156/1 501 753), and in the eastern and central area were 3.41%(17 173/503 130) and 3.56%(14 499/407 739), respectively, higher than 2.28% (13 484/590 884) of western area (P<0.05). The nationwide MG subsequent screen rate was 2.78%(41 694/1 501 753), and in the eastern and central area were 3.19%(16 036/503 130) and 3.29% (13 421/407 739), respectively, higher than 2.07%(12 237/590 884) of western area (P<0.05). The nationwide biopsy rate was 0.23%(3 462/1 501 753), and in the central area were 0.26%(1 078/407 739), respectively, higher than 0.21%(1 247/590 884) of western area and 0.23% (1 137/503 130) of eastern area (P<0.05). The nationwide biopsy PPV was 37.00%(1 281/3 462). The biopsy PPV of eastern area was (34.30%, 390/1 137), lower than 39.33% (424/1 078) of central area (P<0.05). A total of 1 281 cases of breast cancer were detected, the detection rate was 0.85‰(1 281/1 501 753), and the detection rates of central area was 1.04‰ (424/407 739), higher than 0.79‰(467/590 884) of western area and 0.78‰(390/503 130) of eastern area (P<0.05). The BUS initiate screening positive rate from detected breast cancer cases was 96.96%(1 242/1 281), the MG subsequent screening positive rate was 2.42%(31/1 281). The nationwide early diagnosis rate was 85.25%(1 092/1 281), and in the eastern and central areas were 87.95%(343/390) and 88.21%(374/424), higher than 80.30%(375/467) of western area (P<0.05). The screening rate of on or above stage Ⅱ breast cancer in eastern area was 55.64%(217/390), lower than 64.62%(374/424) of central area and 62.31%(291/467) of western area. The missing detection rate was 0.62%(8/1 281) and false positive rate was 1.20%(17 528/1 464 149). Conclusions: The BUS process optimization of breast cancer screening scheme is reasonable and applicable to China rural women. The effectiveness and quality of eastern area are superior to those of central and western area.

[Effects of orlistat and metformin on metabolism and gonadal function in overweight or obese patients with polycystic ovary syndrome].

The aim of this study was to assess the effects of orlistat or metformin treatment on lipid and glucose metabolism, and gonadal function in obese/overweight women with polycystic ovary syndrome (PCOS). A total of 39 patients diagnosed with PCOS were randomly (digital table method) divided into orlistat treatment group (20 cases) and metformin treatment group (19 cases). Compared with those before, treatment with either orlistat or metformin significantly reduced body weight, body mass index (BMI), hip circumferences, and serum insulin levels of the PCOS patients both at the end of 3 months and 6 months (P<0.05). No significant differences could be viewed between orlistat and metformin treated subjects. Moreover, orlistat treatment significantly lowered the levels of low-density lipoprotein cholesterol, total cholesterol, fasting blood glucose, and homeostasis model assessment-insulin resistance (HOMA-IR) (P<0.05), while there were no significant changes in above parameters with metformin treatment. The improvement of menstrual cycle was observed after 6-month treatment in both groups (P<0.05). However, changes in polycystic ovarian morphology by ultrasound were only observed in orlistat treated group. In conclusion, orlistat is comparable with metformin in weight loss and improvement of insulin resistance and menstrual cycle, and is superior to metformin in improvement of lipid metabolism in overweight/obese PCOS patients.

[Changes in platelet related parameters in obese patients after sleeve gastrectomy].

To compare changes in platelet related parameters in obese patients before and after sleeve gastrectomy (SG), we retrospectively analyzed the clinical data of 31 obese patients who underwent SG in Peking Union Medical College Hospital from December 2012 to September 2020. Results showed that compared with those before surgery, platelet count (PLT) decreased significantly at 2-12 weeks of follow-up (P=0.009), while platelet distribution width (PDW), mean platelet volume (MPV), and large platelet ratio (P-LCR) increased significantly at the same periods of follow-up after operation (P<0.001). However, the levels of PDW, MPV, and P-LCR began to decrease at 16-55 weeks when compared with those at 2-12 weeks of follow-up (P<0.01). PLT was positively correlated with white blood cells and neutrophils at 2-12 weeks of follow-up and positively correlated with high sensitivity C-reactive protein at 16-55 weeks of follow-up after operation (P<0.05).

[Analysis of the reported data of National Cervical Cancer Screening Program in Rural Areas in China from 2009 to 2018].

Objective: To analyze the effectiveness of the National Cervical Cancer Screening Program in Rural Areas (NCCSPRA) in China. Methods: Data were collected in the form of quarterly statistical tables reported by NCCSPRA counties in 30 provinces (Hong Kong, Macao and Taiwan province of China were not included into the NCCSPRA, and Tibet Autonomous Region carried out the program but did not reported the data) from 2009 to 2018. The women aged 35-64 years with sexual behavior and the identity (Hukou) of rural area in these project counties were included into the NCCSPRA, and women receiving hysterectomy for non-cervical cancer or non-cervical lesions were excluded. The following indicators were analyzed: the positive rates of different screening methods, the abnormality rates of colposcopy and histopathology, the detection rate of precancerous lesions, the detection rate of cervical cancer and the rate of early diagnosis. Results: A total of 85 041 490 women aged 35-64 in rural areas received free cervical cancer screening and diagnosis if necessary. On the whole, the abnormality rate of cytology, HPV testing, VIA/VILI, colposcopy and histopathology was 3.71%(2 567 610), 9.91%(331 158), 10.10%(1 167 930), 28.85%(1 420 847), and 21.20%(303 068) respectively. The detection rate of cervical precancerous lesions was 153.88/100 000, and increased from 106.85/100 000 in 2012 to 223.89/100 000 in 2018 (P<0.001). Regionally, the east (207.37/100 000) reached higher rate than the middle (177.65/100 000), and the middle higher than the west (108.65/100 000) (P<0.001). The detection rate of invasive cervical cancer was 21.58/100 000, and increased from 18.02/100 000 in 2012 to 26.54/100 000 in 2018 (P<0.001). Regionally, the middle of China (25.46/100 000) reached the higher rate than the east (19.62/100 000) and the west (19.30/100 000) (P<0.001). The rate of early detection was 91.24%(136 140), which increased from 89.60% (11 883)in 2012 to 92.80%(26 962) in 2018 (P<0.001). Regionally, the east of China (94.02%, 37 600) reached the higher rate than the middle(91.06%, 56 488), and the middle higher than the west (89.12%, 42 052) (P<0.001). Conclusions: There are obvious difference in terms of the detection rate of cervical precancerous lesions and the rate of early diagnosis reflecting cervical cancer screening capacity among the eastern, middle and western regions,which showed service inequity among different areas indirectly. The middle and western regions, especially the western regions, are still the focus of future works.

[A case of acute copper sulphate poisoning and literature review].

Objective: To analyze the clinical data of acute copper sulphate poisoning, and discuss the timing and prognosis of the treatment. Methods: The clinical data of a case of acute copper sulphate poisoning treated in Yantaishan Hospital in May 2020 were analyzed, and CNKI, Weipu database and Wanfang database were retrieved with "copper sulfate""poisoning" and "blood purification" as search terms respectively. Such as "copper sulphate/cupric sulfate""poisoning" and "blood purification " were respectively tested in the PubMed database and reviewed the literatures. Results: The patient was admitted to hospital due to "oral copper pentahydrate for 14 h". Plasma exchange and continuous venous hemofiltration were performed on the 2nd day of poisoning, and the liver enzymes and creatinine indexes were normal. The patient recovered and left the hospital after 10 days. After literature retrieval, 13 literatures were screened out, a total of 14 cases were reported. All recovered after blood purification, copper displacement and liver protection. Conclusion: When acute copper sulphate poisoning occurs with multiple organ function damage mainly caused by hemolysis and kidney injury, the treatment with blood purification has a good prognosis while removing copper and organ support.

[Changes of neuron specific enolase in serum of patients with silicosis].

Objective: To explore the changes of neuron specific enolase (NSE) concentration in serum samples of patients with silicosis. Methods: In January 2020, 455 cases of silicosis diagnosed in Yantaishan Hospital from January 2018 to December 2019 were collected, and 60 healthy cases and 120 cases of lung cancer were selected as the healthy group and the lung cancer group. The serum levels of NSE were detected by chemical immunofluorescence assay and compared. Results: The serum NSE level of silicosis patients was [(22.88±7.86) ng/ml], higher than that of healthy group [(17.96±4.42) ng/ml] (P<0.05) . Serum NSE levels in the first, second and third stage silicosis groups were higher than those in the healthy group (P<0.05) , but there was no statistically significant difference between the silicosis groups at different periods (P>0.05) . The serum NSE level of silicosis patients was lower than that of the small cell lung cancer group (P<0.05) , but there was no statistically significant difference between silicosis group and non-small cell lung cancer group (P>0.05) . The area under curve of silicosis NSE was 0.718 (P<0.01) when the cut-off was 17.49 ng/ml, the sensitivity and specificity of NSE was 78% and 57% respectively. Conclusion: The serum NSE level of patients with silicosis is significantly increased, which can be used as an important reference index for the diagnosis and the differential diagnosis of silicosis.

Boundary Criticality of PT-Invariant Topology and Second-Order Nodal-Line Semimetals.

For conventional topological phases, the boundary gapless modes are determined by bulk topological invariants. Based on developing an analytic method to solve higher-order boundary modes, we present PT-invariant 2D topological insulators and 3D topological semimetals that go beyond this bulk-boundary correspondence framework. With unchanged bulk topological invariants, their first-order boundaries undergo transitions separating different phases with second-order boundary zero modes. For the 2D topological insulator, the helical edge modes appear at the transition point for two second-order topological insulator phases with diagonal and off-diagonal corner zero modes, respectively. Accordingly, for the 3D topological semimetal, the criticality corresponds to surface helical Fermi arcs of a Dirac semimetal phase. Interestingly, we find that the 3D system generically belongs to a novel second-order nodal-line semimetal phase, possessing gapped surfaces but a pair of diagonal or off-diagonal hinge Fermi arcs.

[Initial implantation experience and short-term follow-up results of implanting leadless intracardiac transcatheter pacing system].

Objective: To explore the utility and safety of leadless intracardiac transcatheter pacing system. Methods: The study was a prospective observational study. Patients underwent Micra transcatheter pacing system in Beijing Anzhen hospital from December 2019 to January 2020 were enrolled. The baseline characteristics, platelet count, hemoglobin, anticoagulation and/or antiplatelet therapy, mean procedural time, average fluoroscopy time, number of deployment and electrical parameters (threshold, R-wave amplitude, impedance) were recorded. Ultrasonography of bilateral femoral and iliac veins was performed in all patients. Patients were followed including access site complication, adverse event and device evaluation at implant, hospital discharge, 1 and 3 months post-implant. R-wave≥5 mV, impedance between 400 and 1 500 Ω and threshold increase≤1.5 V than implant is considered a stable parameter. Femoral access site complications included hematoma, hemorrhage, pseudoaneurysm, and arteriovenous fistula. Adverse events included dislodgement, cardiac effusion/perforation and infection. Left ventricular end diastolic diameter and ejection fraction before and at 1 month after implant were reported. Results: Five patients were enrolled and pacemaker implantation was successful in all 5 patients. Patients were all males and the average age was (78.4±8.4) years. 2 patients received aspirin and clopidogrel therapy, 1 patient suffered from anemia and thrombocytopenia occurred in 1 patient. No stenosis, occlusion and vascular malformation of bilateral femoral and iliac veins was observed. The mean implant time was (39.6±1.7) minutes. The average fluoroscopy time was (9.2±1.3) minutes and the number of deployment was (1.40±0.55). Electrical parameters(threshold, R-Wave amplitude and impedance) were as follows: (0.40±0.10) V/0.24 ms, (10.80±3.72) mV and (822.00±162.23) Ω at implant; (0.45±0.07) V/0.24 ms, (13.04±2.41) mV, and (748.0±91.5) Ω at discharge, (0.40±0.06) V/0.24 ms, (14.26±4.11) mV, and (700.0±91.7) Ω at 1 month post-implant and (0.39±0.05) V/0.24 ms, 14.40±3.97 mV, and (682.0±96.0) Ω at 3 months post-implant, respectively. Threshold increase was ≤1.5 V compared to that during implantation, electrical parameters were acceptable and stable. There was no difference in LVEDD [(44.00±5.24) mm vs. (44.00±5.34) mm,P=1.000] and EF [(62.00±3.39)% vs. (62.20±3.56)%, P=0.861] before and 1 month post-implant. No incidence of access site complications, cardiac effusion/perforation, dislodgment or infections occurred during the 3 months. Conclusions: The leadless transcatheter pacemaker implantation performed in our study archived a high implant success rate and favorable safety profile as well as associated with low and stable pacing thresholds. The long-term safety and benefit of leadless pacemaker need to be evaluated in future clinical studies.