Lesion Formation Research Articles

IgG4-related Disease: Recent Topics on Immunological Aspects of This Disorder and Their Application in New Treatment Strategies.

IgG4-related disease (IgG4-RD) is a systemic and chronic inflammatory disorder that can affect every part of the body. The formation of tertiary lymphoid tissues (TLT) in the affected organs may be a key phenomenon in understanding the pathogenesis of this disease because T follicular helper (Tfh) 2 cells play an important role in IgG4 class switching within TLT in the affected organs or tissues. TLT formation leads to the formation of masses or swelling of the affected organs. Interleukin (IL)-4 and IL-10 are critical cytokines for IgG4-class switching and are produced in TLT. Other factors, such as CD4-positive (CD4+) cytotoxic T cells, M2 macrophages, and LAG3+ Tfh cells, have been identified as disease-specific contributors to lesion formation. In this review, I describe the current knowledge necessary to understand the pathogenesis of this disease and recent developments in treatment strategies beyond B-cell depletion therapy.

Best practices in robotic magnetic navigation-guided catheter ablation of cardiac arrhythmias, a position paper of the Society for Cardiac Robotic Navigation.

Robotic magnetic navigation (RMN)-guided catheter ablation (CA) technology has been used for the treatment of cardiac arrhythmias for almost 20 years. Various studies reported that RMN allows for high catheter stability, improved lesion formation and a superior safety profile. So far, no guidelines or recommendations on RMN-guided CA have been published. The aim of this consensus paper was to summarize knowledge and provide recommendations on management of arrhythmias using RMN-guided CA as treatment of atrial fibrillation (AF) and ventricular arrhythmias (VA). An expert writing group, performed a detailed review of available literature, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Recommendations on RMN-guided CA are presented in a guideline format with three levels of recommendations to serve as a reference for best practices in RMN procedures. Each recommendation is accompanied by supportive text and references. The various sections cover the practical spectrum from system and patient set-up, EP laboratory staffing, combination of RMN with fluoroscopy and mapping systems, use of automation features and ablation settings and targets, for different cardiac arrhythmias. This manuscript, presenting the combined experience of expert robotic users and knowledge from the available literature, offers a unique resource for providers interested in the use of RMN in the treatment of cardiac arrhythmias.

Molar Incisor Hypomineralisation as a Dental Caries Risk Factor - Is It True?

The development of the human dentition is susceptible to disruption owing to its intricate and delicate nature, encompassing variations in tooth number, anatomical configuration, and the characteristics of enamel, dentine, and cementum. This chapter will specifically address the prevalent defect of molar incisor hypomineralisation (MIH), which can impose a significant treatment burden on individuals. MIH is linked to deleterious alterations in the properties of affected enamel, which can lead to rapid enamel breakdown and carious lesion formation in those at a heightened caries risk. In addition, MIH is associated with tooth sensitivity, dental anxiety, difficulty eating, aesthetic concerns, and negative influence during the child's psychological growth, especially when the MIH is severe. Regarding dental caries, it is essential to note that MIH does not directly increase the risk of caries. However, MIH can alter the way the caries process manifests by creating niches where biofilm can accumulate, complicating oral cleaning efforts. Additionally, MIH adversely modifies the physicochemical properties of enamel, influencing how this "hardest of tissues" responds to cariogenic challenges.

TRIM65 promotes vascular smooth muscle cell phenotypic transformation by activating PI3K/Akt/mTOR signaling during atherogenesis

Background and aimsTripartite motif (TRIM65) is an important member of the TRIM protein family, which is a newly discovered E3 ligase that interacts with and ubiquitinates various substrates and is involved in diverse pathological processes. However, the function of TRIM65 in atherosclerosis remains unarticulated. In this study, we investigated the role of TRIM65 in the pathogenesis of atherosclerosis, specifically in vascular smooth muscle cells (VSMCs) phenotype transformation, which plays a crucial role in formation of atherosclerotic lesions. Methods and ResultsBoth non-atherosclerotic and atherosclerotic lesions during autopsy were collected singly or pairwise from each individual (n = 16) to investigate the relationship between TRIM65 and the development of atherosclerosis. In vivo, Western diet-fed ApoE−/− mice overexpressing or lacking TRIM65 were used to assess the physiological function of TRIM65 on VSMCs phenotype, proliferation and atherosclerotic lesion formation. In vitro, VSMCs phenotypic transformation was induced by platelet-derived growth factor-BB (PDGF-BB). TRIM65-overexpressing or TRIM65-abrogated primary mouse aortic smooth muscle cells (MOASMCs) and human aortic smooth muscle cells (HASMCs) were used to investigate the mechanisms underlying the progression of VSMCs phenotypic transformation, proliferation and migration. Increased TRIM65 expression was detected in α-SMA-positive cells in the medial and atherosclerotic lesions of autopsy specimens. TRIM65 overexpression increased, whereas genetic knockdown of TRIM65 remarkably inhibited, atherosclerotic plaque development. Mechanistically, TRIM65 overexpression activated PI3K/Akt/mTOR signaling, resulting in the loss of the VSMCs contractile phenotype, including calponin, α-SMA, and SM22α, as well as cell proliferation and migration. However, opposite phenomena were observed when TRIM65 was deficient in vivo or in vitro. Moreover, in cultured PDGF-BB-induced TRIM65-overexpressing VSMCs, inhibition of PI3K by treatment with the inhibitor LY-294002 for 24 h markedly attenuated PI3K/Akt/mTOR activation, regained the VSMCs contractile phenotype, and blocked the progression of cell proliferation and migration. ConclusionsTRIM65 overexpression enhances atherosclerosis development by promoting phenotypic transformation of VSMCs from contractile to synthetic state through activation of the PI3K/Akt/mTOR signal pathway.

Effects of Contact Force on Lesion Size During Pulsed Field Catheter Ablation: Histochemical Characterization of Ventricular Lesion Boundaries.

Effects of contact force (CF) on lesion formation during pulsed field ablation (PFA) have not been well validated. The purpose of this study was to determine the relationship between average CF and lesion size during PFA using a swine-beating heart model. A 7F catheter with a 3.5-mm ablation electrode and CF sensor (TactiCath SE, Abbott) was connected to a PFA system (CENTAURI, Galvanize Therapeutics). In 5 closed-chest swine, biphasic PFA current was delivered between the ablation electrode and a skin patch at 40 separate sites in right ventricle (28 Amp) and 55 separate sites in left ventricle (35 Amp) with 4 different levels of CF: (1) low (CF range of 4-13 g; median, 9.5 g); (2) moderate (15-30 g; median, 21.5 g); (3) high (34-55 g; median, 40 g); and (4) no electrode contact, 2 mm away from the endocardium. Swine were sacrificed at 2 hours after ablation, and lesion size was measured using triphenyl tetrazolium chloride staining. In 1 additional swine, COX (cytochrome c oxidase) staining was performed to examine mitochondrial activity to delineate reversible and irreversible lesion boundaries. Histological examination was performed with hematoxylin and eosin and Masson trichrome staining. Ablation lesions were well demarcated with triphenyl tetrazolium chloride staining, showing (1) a dark central zone (contraction band necrosis and hemorrhage); (2) a pale zone (no mitochondrial activity and nuclear pyknosis, indicating apoptosis zone); and a hyperstained zone by triphenyl tetrazolium chloride and COX staining (unaffected normal myocardium with preserved mitochondrial activity, consistent with reversible zone). At constant PFA current intensity, lesion depth increased significantly with increasing CF. There were no detectable lesions resulting from ablation without electrode contact. Acute PFA ventricular lesions show irreversible and reversible lesion boundaries by triphenyl tetrazolium chloride staining. Electrode-tissue contact is required for effective lesion formation during PFA. At the same PFA dose, lesion depth increases significantly with increasing CF.

Multidisciplinary experts consensus on diagnosis and treatment of precancerous lesions of hepatocellular carcinoma (2023 version)

According to the latest statistical data, the incidence and mortality rate of hepatocellular carcinoma in China are still on the rise, posing a major threat to the health of the Chinese population. The occurrence is closely related to the formation of precancerous lesions in the liver. The clinical and basic research on precancerous lesions of hepatocellular carcinoma has developed rapidly, and the concepts and specific techniques for diagnosis and treatment have also undergone new changes and advancements. Therefore, based on the first version in 2020, this consensus has organized multidisciplinary experts to compile and improve a new version by integrating the latest progress in their respective professional fields at home and abroad. It aims to enhance clinicians' understanding of precancerous lesions of hepatocellular carcinoma standardize the pathology, imaging, and molecular diagnostic criteria, broaden early screening methods, formulate scientifically rational treatment plans, and help promote the advancement of diagnosis and treatment strategies and to enhance the overall 5-year survival rate of patients with hepatocellular carcinoma.

The role of microcomedones in acne: Moving from a description to treatment target?

A major factor in the pathogenesis of acne is ductal hyperproliferation in the pilosebaceous glands. This takes the form of invisible microcomedones and leads to the subsequent formation of both inflammatory and non-inflammatory clinical lesions. Microcomedones are the initial stage in the cyclical development of acne, so called comedogenesis. Microcomedones can be detected using cyanoacrylate skin surface stripping, electron microscopy, reflection confocal microscopy and other techniques. It has been proposed that the density and the size of microcomedones are positively correlated with acne severity. Thus, the purpose of this review is to summarize the root causes of acne, and suggest that treatment of microcomedones could, at least in part, resolve acne lesions and prevent relapse.

Complete genome sequence of eight LEE-negative Shiga toxin-producing Escherichia coli strains isolated from patients with hemolytic-uremic syndrome.

Major serotypes of Shiga toxin-producing Escherichia coli (STEC) carry a locus of enterocyte effacement (LEE), which is required for attaching and effacing lesion formation. Genome information of LEE-negative STEC is scarce despite their virulence potential. We present the complete genome sequences of eight LEE-negative STEC isolates from hemolytic-uremic syndrome patients.

TIM-3 regulates the proliferation by BDNF-mediated PI3K/AKT axis in the process of endometriosis

BackgroundT cell immunoglobulin and mucin domain-containing molecule-3 (TIM-3) initially discovered on the surface of Th1 cells, negatively regulates immune responses and mediates apoptosis of Th1 cells. An increasing number of studies have since shown that TIM-3 is crucial in the genesis and development of immune diseases, cancers, and chronic infectious illnesses. However, the effect of TIM-3 on endometriosis is still unknown.MethodsQuantitative real-time polymerase chain reaction, western blotting, and immunohistochemistry were used to measure TIM-3 levels in endometriosis. Cell Counting Kit-8, 5-ethynyl-2’-deoxyuridine, colony-forming, Transwell® migration, Matrigel® invasion, and flow cytometry assays were used to explore the function of TIM-3 in vitro, and xenograft experiments in nude mice were used to assess its role in vivo. According to the RNA seq, brain-derived neurotrophic factor (BDNF) was screened. The involvement of specific proliferation-related signaling molecules was determined by transfecting a plasmid and adding an inhibitor in vivo and in vitro.ResultsTIM-3 mRNA and protein expression levels were significantly higher in eutopic and ectopic endometrial tissues than in normal endometrial tissues. By examining the effects of TIM-3 overexpression and knockdown on cell proliferation, migration, and invasion in vitro, and lesions formation in vivo, we found that the expression of TIM-3 was positively correlated with cell proliferation and clone formation in vitro, as well as lesions growth in nude mice. By adding the phosphatidylinositol 3 kinase/protein kinase B(PI3K/AKT) pathway inhibitor LY294002 and knocking down PI3K, we further verified that TIM-3 promotes proliferation in vivo and in vitro via the PI3K pathway. By transfecting the plasmid into ESC cells and gave inhibitors to endometriotic rats models, we tested that TIM-3 regulates the proliferation by BDNF-mediated PI3K/AKT axis.ConclusionTIM-3 can promote the proliferation of endometriosis by BDNF-mediated PI3K/AKT axis in vivo and in vitro, which may provide a new therapeutic target for the treatment of endometriosis.

Circulating biomarkers in familial cerebral cavernous malformation

BackgroundCerebral Cavernous Malformation (CCM) is a rare cerebrovascular disease, characterized by the presence of multiple vascular malformations that may result in intracerebral hemorrhages (ICH), seizure(s), or focal neurological deficits (FND). Familial CCM (fCCM) is due to loss of function mutations in one of the three independent genes KRIT1 (CCM1), Malcavernin (CCM2), or Programmed Cell death 10 (PCDC10/CCM3). The aim of this study was to identify plasma protein biomarkers of fCCM to assess the severity of the disease and predict its progression. MethodsHere, we have investigated plasma samples derived from n=71 symptomatic fCCM patients (40 female/31 male) and n=17 healthy donors (HD) (9 female/8 male) of the Phase 1/2 Treat_CCM trial, using multiplexed protein profiling approaches. FindingsBiomarkers as sCD14 (p= 0.00409), LBP (p= 0.02911), CXCL4 (p= 0.038), ICAM-1 (p= 0.02013), ANG2 (p= 0.026), CCL5 (p= 0.00403), THBS1 (p= 0.0043), CRP (p= 0.0092), and HDL (p= 0.027), were significantly different in fCCM compared to HDs. Of note, sENG (p= 0.011), THBS1 (p= 0.011) and CXCL4 (p= 0.011), were correlated to CCM genotype. sROBO4 (p=0.014), TM (p=0.026) and CRP (p=0.040) were able to predict incident adverse clinical events, such as ICH, FND or seizure. GDF-15, FLT3L, CXCL9, FGF-21 and CDCP1, were identified as predictors of the formation of new MRI-detectable lesions over 2-year follow-up. Furthermore, the functional relevance of ang2, thbs1, robo4 and cdcp1 markers was validated by zebrafish pre-clinical model of fCCM. InterpretationOverall, our study identifies a set of biochemical parameters to predict CCM progression, suggesting biological interpretations and potential therapeutic approaches to CCM disease. FundingItalian Medicines Agency, Associazione Italiana per la Ricerca sul Cancro (AIRC), ERC, Leducq Transatlantic Network of Excellence, Swedish Research Council.

Dynamics of functional impairments during focal transient ischemia in three-dimensional cortical space

Ischemic injury in the cerebral cortex results in decreased electrical activity across all frequency bands and the emergence of abnormal electrophysiological patterns, including spreading depolarization (SD) and negative ultraslow potential (NUP) [1, 2]. Despite this, the specific dynamics of these changes in electrical activity within the three-dimensional cortical space during ischemia remain incompletely described and poorly understood. To simultaneously investigate changes in electrical activity across the layers of the cerebral cortex and in the horizontal cortical space, we used two linear 16-channel silicone probes (Neuronexus, USA) in combination with a flexible transparent 60-channel matrix of subdural electrodes (MIPT, Russia) and intrinsic optical signal imaging (IOS, 665 nm, transillumination mode) during focal ischemia induced by intracortical injection of the potent vasoconstrictor endothelin-1 (ET-1, 1 μL, 1 μM). These experiments were carried out in head-restrained rats under urethane anesthesia (1.5 g/kg). Formation of the ischemic lesion following ET-1 administration was correlated with clusters of SDs that demonstrated considerable variability in their propagation patterns within both vertical and horizontal planes. The initial SDs originated from the injection site of ET-1 and diffused across all cortical layers. Subsequently, the initiation point of the ensuing SDs gradually shifted towards the deeper layers while the electrical activity showed inadequate recovery between SDs within the injection site. SDs originating in the surrounding cortex did not invade the area near the injection point. Instead, they tended to spread around, often compartmentalizing in the superficial layers of the cortex. Some SDs were observed deep in the cortex, while others were detected on the surface via superficial electrodes and IOS, without leaving typical intracortical electrode traces. Electrographic activity was significantly depressed, especially in the superficial layers around the injection site, three hours after ET-1 administration. However, it returned to pre-ET-1 levels at the remote site, with a spatial gradient observed in subdural electrodes. Functional impairments corresponded to the histological lesion observed in coronal brain sections. Recently discovered NUPs were initiated by SD and were most prominent in the electrodes closest to the ET-1 injection site. These NUPs reached their maximal amplitude at one hour and subsided three hours after ET-1 injection. Our research indicates intricate dynamics in the creation of an ischemic focal point. The data gathered suggest that the emergence of cerebral harm during focal ischemia is associated with the growth of a focus extending both horizontally and vertically across cortical dimensions. This growth is fueled by the generation of SDs within the ischemic penumbra.

Local Effects of Steroid Hormones within the Bone Microenvironment.

Steroid hormone production via the adrenal cortex, gonads, and placenta (so-called glandular steroidogenesis) is responsible for the endocrine control of the body's homeostasis and is organized by a feedback regulatory mechanism based on the hypothalamus-pituitary-steroidogenic gland axis. On the other hand, recently discovered extraglandular steroidogenesis occurring locally in different tissues is instead linked to paracrine or autocrine signaling, and it is independent of the control by the hypothalamus and pituitary glands. Bone cells, such as bone-forming osteoblasts, osteoblast-derived osteocytes, and bone-resorbing osteoclasts, respond to steroid hormones produced by both glandular and extraglandular steroidogenesis. Recently, new techniques to identify steroid hormones, as well as synthetic steroids and steroidogenesis inhibitors, have been introduced, which greatly empowered steroid hormone research. Based on recent literature and new advances in the field, here we review the local role of steroid hormones in regulating bone homeostasis and skeletal lesion formation. The novel idea of extraglandular steroidogenesis occurring within the skeletal system raises the possibility of the development of new therapies for the treatment of bone diseases.

Control of skin damages caused by oxidative stress using mangiferin and naringin co-loaded in phospholipid vesicles

Mangiferin and naringin, two naturally occurring antioxidant molecules, were co-loaded in phospholipid vesicles designed for skin delivery. Ultradeformable-liposomes containing tween 80 as edge activator, were used as basic formulation, which was modified adding glycerol (glycerosomes) or a mixture of glycerol and ethanol (et-glycerosomes) and further enriched with a polymer, sodium hyaluronate (glycerohyalurosomes and et-glycerohyalurosomes), to evaluate the role of vesicle composition on their features and performances. Mean dimeter, polydispersity index and zeta potential of prepared vesicles were measured along with their stabilitcay on storage for 90 days, rheological behavior and suitability as systems for the delivery of these active molecules into and through the skin. Vesicles enriched with sodium hyaluronate were the most stable and the smallest and favored the deposition of both mangiferin and naringin in the whole skin, in a better extent than those without polymer. All the vesicles were highly biocompatible and capable of protecting fibroblasts against hydrogen peroxide-induced oxidative damages in vitro. Once more, glycerohyalurosomes and et-glycerohyalurosomes where those which improved the most the beneficial effect of mangiferin and naringin, as they were capable of effectively counteracting the formation of skin lesion, or even promoting the wound healing, thanks to their greater ability to inhibit both myeloperoxydase activity and oedema formation in vivo in a model mouse in which wound was induced using phorbol acetate.

PREVALENCE OF GASTRIC PRECANCEROUS CONDITIONS : A SYSTEMATIC REVIEW

Background: Gastric carcinoma is a common malignant disease associated with an unfavorable prognosis in the case of late dia-gnosis. The most significant precancerous condition is chronic atrophic gastritis and intestinal metaplasia caused by Helicobacter pylori infection. These longlasting changes may lead to formation of dysplastic precancerous lesions. Methods: By comparing itself to the standards set by the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) 2020, this study was able to show that it met all of the requirements. So, the experts were able to make sure that the study was as up-to-date as it was possible to be. For this search approach, publications that came out between 2013 and 2023 were taken into account. Several different online reference sources, like Pubmed and SagePub, were used to do this. It was decided not to take into account review pieces, works that had already been published, or works that were only half done. Result: In the PubMed database, the results of our search brought up 1.045 articles, whereas the results of our search on SagePub brought up 701 articles. The results of the search conducted for the last year of 2013 yielded a total 12 articles for PubMed and 8 articles for SagePub. In the end, we compiled a total of 4 papers, 3 of which came from PubMed and 1 of which came from SagePub. We included five research that met the criteria. Conclusion: Precancerous conditions including chronic atrophic gastritis gastritis, metaplasia, foveolar hyperplasia and gastric hyperplastic polyps derived from the gastric epithelium have been concluded, based on the overview of gastric epithelial histological organization and its renewal.

Role of tenascin C in lesion formation in early peritoneal endometriosis

To identify cytokines or extracellular matrix components that contribute to adhesion to, and invasion of, the peritoneum, proximal to lesions in the early phase of endometriosis. Laboratory-based study. University Hospital and Laboratory of Animal Science. Five women with ovarian endometrioma, 138 wild-type (WT) C57BL/6N mice, and 48 Tenascin C (Tnc) knockout (TncKO) mice. To establish a murine endometriosis model, 20 pieces of minced uterine tissue fragments from each horn were administered intraperitoneally to syngeneic mice. Three days later, endometriotic lesions and peritoneal tissues were collected. Separately, we transfected human peritoneal mesothelial cells (HMrSV5) or human endometrial stromal cells (hESCs) with Tnc small interfering ribonucleic acid. We employed a polymerase chain reaction array to profile gene expression in the murine peritoneum, in both peritoneum distal to lesions and peritoneum surrounding lesions (PSL). The expression of upregulated genes in the PSL was verified in the peritoneal samples by real-time reverse transcription-polymerase chain reaction. TncKO mice were used to investigate the role of Tnc in the development of endometriosis. We evaluated the proliferative activity or inflammatory state of lesions by Ki67 or CD3 immunostaining. Intraperitoneal distribution of macrophages was assessed by fluorescence-activated cell sorting. Using Tnc small interfering ribonucleic acid, we examined the invasive capacity of hESCs in a coculture system with HMrSV5. Tnc gene expression was significantly higher in PSL than in peritoneum distal to lesions. The weight and number of TncKO lesions in TncKO hosts were lower than those of WT lesions in WT hosts. In contrast, the weight and number of nonattached TncKO lesions in TncKO hosts were higher than those of nonattached WT lesions in WT hosts. We observed decreased Ki67-positive cells or H-scores for CD3, a lower proportion of M1 macrophages, and a higher proportion of M2 macrophages in TncKO lesions in TncKO recipients. Silencing of Tnc expression in hESCs and HMrSV5 diminished the invasivity of hESCs. Tnc may be a crucial factor in the development of early peritoneal endometriosis.

Reinke's Edema and Risk Factors, A Case-Control Study.

Reinke's edema (RE) is a benign pathological non-inflammatory disorder of the vocal folds with a wide range of clinical manifestations. We aim to investigate the relationship between Reinke's edema and some common inhalant abuse. In this case-control study, subjective consisted of 23 patients with RE (the cases), and 50 patients with sinusitis (control) who underwent surgery in the Department of Otolaryngology, between 2015 and 2020. Demographic characteristics, history of some related disease, methods, and the duration of cigarette, and opium consumption were collected through the patients' files. The chi-square (χ²) test was run to analyze the differences in the categorical and, and the Independent Sample T-test was used to compare two sample means from unrelated groups. A significant level (p-value) was considered less than 0.05. The mean age was 54 ± 12 years, and 42 ± 11 years, respectively for Reinke's edema and sinusitis. More women had been recorded in the RE group, compared to men. Allergy, unprincipled use of voice and talkativeness, history of laryngeal surgery, and type of disease were correlated to RE (p < 0.05). Also, cigarette smoking was significantly correlated with Reinke's edema. The average number of cigarettes per day, the duration of smoking, and opium consumption were more frequent in RE (P < 0.05). 90% of the RE and 4% of sinusitis patients were opium consumers. There was a statistically significant difference in the methods of substance use in the two groups of cases and control (p < 0.0001). Among the different methods, the poker and stone method was the most common (69.6%), and the opium smoking pipe was the second most common method. This study also confirmed the hazardous effects of smoking and inhaling opiates in the formation of lesions of the pharynx and larynx. In particular, longer use of these substances will be associated with more serious side effects. Therefore, it seems that people who are addicted to opiates should undergo periodic visits and counseling to reduce and stop their use.

Squalene Peroxidation and Biophysical Parameters in Acne-Prone Skin: A Pilot "In Vivo" Study.

Nowadays, acne vulgaris therapies are often unsuccessful. One of the responsible factors for the formation of comedones and inflammatory lesions could be the peroxidation of squalene, a hydrocarbon representing one of the major components of human sebum. This peroxidation is increased by solar irradiation. The purpose of this work was to set up an in vivo method for the extraction and quantification of squalene from acne skin and to correlate the results with biophysical skin parameters such as sebum amount, protein content and TEWL. Healthy volunteers were used as control. The results obtained demonstrated that acne-prone skin had a major quantity of squalene, and, in the stratum corneum area, its peroxide form is present. Moreover, Spearman's rank correlation showed a positive correlation between sebum content and peroxide squalene and between porphyrin intensity and peroxide squalene.

The effect of ablation settings on lesion characteristics with DiamondTemp ablation system: An exvivo experiment.

Creating large lesion in ablations using the DiamondTemp (DTA) ablation system may reduce the frequency of arrhythmia recurrence and allow the treatment of ventricular arrhythmias. Therefore, this study aimed to investigate whether power, application time, contact force (CF), and contact angle affect lesion formation in the ventricles. Ablations were delivered to porcine myocardial preps to evaluate the lesion characteristics. Ablations were conducted with a maximum power of 50 W, target temperature of 58°C, CF of 10, 20, or 30 g, and contact angle between the catheter tip and tissue. The ablation durations were 15, 30, 60 s, 15 s × 2, or 30 s × 2. Steam pops occurred only in cases with perpendicular contact. The lesion depth was larger in all settings in the perpendicular orientation than in the parallel orientation. The temperatures were lower in all settings in the perpendicular orientation than in the parallel orientation. The lesions became larger as CF increased with perpendicular contact and duration of ≥30 s. The longer application time resulted in larger surface area, depth, and volume of the lesion. Lesion depth was greater with single application of 30 and 60 s than with 15 s × 2 and 30 s × 2, respectively. It is important to perform a single prolonged application as much as possible to create deeper lesions. Parallel contact with the tissue should be maintained to take advantage of the temperature sensor's capabilities to avoid pop phenomenon.

Evaluation and comparison of impedance and amplitude changes in lesion index-guided pulmonary vein isolation.

The lesion index (LSI) has been used to estimate lesion formation after radiofrequency catheter ablation. However, the impedance drop and decrease in bipolar amplitude of intracardiac electrograms, which are parameters that are traditionally used to predict effective ablation lesions, are not used to calculate LSI. Therefore, we aimed to investigate the association between LSI and traditional parameters. We retrospectively investigated 1355 ablation points from 31 patients who underwent LSI-guided pulmonary vein isolation (PVI) using TactiCath. All points were classified into 3 groups based on the impedance drop: (i) <10 Ω (n = 67), (ii) 10-20 Ω (n = 909), and (iii) >20 Ω (n = 379). The LSI targets were 4.5 for the posterior left atrium and 5.2 for the anterior left atrium. After excluding 583 points at which it was difficult to measure the amplitude, 772 ablation points during sinus rhythm were included in the analysis of bipolar amplitude. The target LSI was achieved at 1177 points (86.9%). The median total impedance drop and amplitude just after ablation were 16.0 [13.0-20.0] Ω and 0.21 [0.14-0.30] mV, respectively. There were significant differences among the 3 groups in the impedance and amplitude before ablation, power, target LSI, final LSI, contact force, and interlesion distance. An impedance drop of >10 Ω or an amplitude reduction of >50% was achieved at 95% and 82% of the study points, respectively. There were no major complications at any of the ablation points. LSI-guided PVI seemed to be useful for making sufficient ablation lesions, as assessed by the conventional parameters of impedance and amplitude change.

Catheter Ablation of Persistent AF-Where are We Now?

Persistent atrial fibrillation (AF) is a diverse condition that includes various subtypes and underlying causes of arrhythmia. Progress made in catheter ablation technology in recent years has significantly enhanced the durability of ablation. Despite these advances however, the effectiveness of ablation in treating persistent AF is still relatively modest. Studies exploring the mechanisms behind persistent AF have identified substrate-driven focal and re-entrant sources within the atrial body as crucial in sustaining AF among individuals with persistent AF. Furthermore, the widespread adoption of atrial late gadolinium enhancement cardiac magnetic resonance (CMR) imaging and the ongoing refinement of invasive voltage mapping techniques have allowed for detailed assessment of fibrotic remodelling prior to or at the time of procedure. Translation into clinical practice, however, has yielded overall disappointing results. The clinical application of AF mapping in ablation procedures has not shown any substantial advantages beyond the use of pulmonary vein isolation (PVI) alone and adjunct ablation of fibrotic areas has yielded conflicting results in recent randomized trials. The emergence of pulsed field ablation represents a welcome development in the field and several studies have demonstrated an enhanced safety profile and increased procedural efficiency with this non-thermal energy modality. Pulsed field ablation also holds promise for safe and efficient substrate ablation beyond the pulmonary veins, but further trials are needed to assess its impact on longer term success rates. Continued advancements in our comprehension of AF mechanisms, alongside ongoing developments in catheter technology aimed at safe formation of transmural lesions, are essential for achieving better clinical outcomes for patients with persistent AF.