Effectiveness Of Thermal Ablation Research Articles

Resection versus resection with ablation: Analysis from the colorectal liver operative metastasis international collaborative.

Thermal ablation has recently become a key therapy for the treatment of colorectal liver metastasis (CLM). However, the role of ablation in combination with resection has not yet been firmly established. We hypothesize that in patients with CLM, those who undergo liver resection with ablation (RA) have similar outcomes compared with those who undergo liver resection only. We reviewed a multicenter international database of 906 surgical procedures for CLM from 5 high volume hepatobiliary surgical units. Patients undergoing RA (n = 63) were matched based on the number of lesions and tumor size using a 1:1 balanced propensity score analysis with those having resection only (n = 63). Our primary outcomes were overall survival (OS) and disease-free survival (DFS). The mean age of our cohort was 58 ± 11 years, with 43% females. With a median follow-up of 70.8 months, patients in the resection and RA group had a median OS of 45.1 and 54.8 months (p = 0.71), respectively. The median DFS was 22.7 and 14.2 months (p = 0.045), respectively. Using a multivariate Cox proportional hazards regression model, the treatment approach was not associated with OS (p = 0.94) or DFS (p = 0.059). A higher number of lesions is independently associated with worse DFS (hazard ratio: 1.12, p < 0.01). When there was disease recurrence, the region of recurrence was similar between the RA versus resection only groups (p = 0.27), but there was a shorter time to recurrence in the RA group (p = 0.002). For CLM, the treatment approach was not significantly associated with OS or DFS, while tumor biology likely played an important role. Prospective research on the quality and effectiveness of thermal ablation combined with hepatic resection is warranted.

The effectiveness and safety of thermal ablation for thyroid carcinoma lymph node metastasis are affected by the diameter of metastatic lymph nodes: A meta-analysis

BackgroundTo explore the diameter of lymph nodes with metastatic thyroid carcinoma and the effectiveness and safety of thermal ablation. MethodsSeveral databases were searched for literature on the treatment of thyroid carcinoma metastatic lymph nodes by thermal ablation. A subgroup analysis was performed according to the diameter of the metastatic lymph nodes. The measures included pooled estimates of mean volume reduction, pooled proportions of total disappearance and recurrence, and the pooled proportions of overall complications. ResultsThere were 20 studies with 372 patients and 620 metastatic lymph nodes included. Based on the average maximum diameter of the metastatic lymph nodes, they were divided into three groups: A (≤ 10 mm), B (10 < diameter ≤ 20 mm), and C (> 20 mm). The study results indicated a significant decrease in the average volume only in groups A and B. The ratio of tumor disappearance showed that group A had the highest percentage, followed by group B and then group C. The recurrence rates were comparable between groups A and B, but slightly lower than in group C. Moreover, the overall complication rates for the three groups were ranked as follows: group A > group C > group B. ConclusionOverall, thermal ablation is an effective and safe treatment for thyroid cancer metastatic lymph nodes with diameters of 10-20mm.

Design of the multicentre randomised controlled BENTO trial to demonstrate patient-relevant benefit of bronchoscopic lung volume reduction using thermal vapour ablation in the German healthcare system for patients with upper lobe emphysema: a study protocol

IntroductionApplication of vapour ablation as a novel approach to lung volume reduction has positive effects in patients with severe emphysema. The BENTO study is a randomised, controlled, open, multicentre trial,...

Spatially modulated ablation driven by chaotic attractors in human lung epithelial cancer cells

A significant modification in photoinduced energy transfer in cancer cells is reported by the assistance of a dynamic modulation of the beam size of laser irradiation. Human lung epithelial cancer cells in monolayer form were studied. In contrast to the quantum and thermal ablation effect promoted by a standard focused Gaussian beam, a spatially modulated beam can caused around 15% of decrease in the ablation threshold and formation of a ring-shaped distribution of the photothermal transfer effect. Optical irradiation was conducted in A549 cells by a 532 nm single-beam emerging from a Nd:YVO4 system. Ablation effects derived from spatially modulated convergent waves were controlled by an electrically focus-tunable lens. The proposed chaotic behavior of the spatial modulation followed an Arneodo chaotic oscillator. Fractional dynamic thermal transport was analyzed in order to describe photoenergy in propagation through the samples. Immediate applications of chaos theory for developing phototechnology devices driving biological functions or phototherapy treatments can be considered.

Development and Validation of an Algorithm Model for Predicting Heat Sink Effects during Pulmonary Thermal Ablation

The aim of this study was to develop an algorithm model to predict the heat sink effect during thermal ablation of lung tumors and to assist doctors in the formulation and adjustment of surgical protocols. The heat sink effect is an important factor affecting the therapeutic effect of tumor thermal ablation. At present, there is no algorithm model to predict the intraoperative heat sink effect automatically, which needs to be measured manually, which lacks accuracy and consumes time. To construct a segmentation model based on a convolutional neural network that can automatically identify and segment pulmonary nodules and vascular structure and measure the distance between the nodule and vascular. First, the classical Faster RCNN model was used as the nodule detection network. After obtaining the bounding box of pulmonary nodules, the VSPP-NET model was used to segment nodules in the bounding box. The distance from the nodule to the vasculature was measured after the surrounding vasculature was segmented by the VSPP-NET model. The lung CT images of 392 patients with pulmonary nodules were used as the training data for the algorithm. 68 cases were used as algorithm validation data, 29 as nodule algorithm test data, and 80 as vascular algorithm test data. We compared the heat sink effect of 29 cases of data with the results of the algorithm model and expert segmentation and compared the difference between the two results. In pulmonary CT image vasculature segmentation, the recall and precision of the algorithm model reached >0.88 and >0.78, respectively. The average time for automatic segmentation of each image model is 29 seconds, and the average time for manual segmentation is 158 seconds. The output image of the model shows that the results of nodule segmentation and nodule distance measurement are satisfactory. In terms of heat sink effect prediction, the positive rate of the algorithm group was 28.3%, and that of the expert group was 32.1%, with no significant difference between the two groups (p=0.687). The algorithm model developed in this study shows good performance in predicting the heat sink effect during pulmonary thermal ablation. It can improve the speed and accuracy of nodule and vessel segmentation, save ablation planning time, reduce the interference of human factors, and provide more reference information for surgeons to make ablation plans to improve the ablation effect.

Immunostimulatory effects of thermal ablation: Challenges and future prospects.

This literature explores the immunostimulatory effects of thermal ablation in the tumor microenvironment, elucidating the mechanisms such as immunogenic cell death, tumor-specific antigens, and damage-associated molecular patterns. Furthermore, it outlines critical issues associated with thermal ablation-induced immunostimulatory challenges and offers insights into future research avenues and potential therapeutic strategies.

Dual-Frequency Impedance Matching Network Design Using Genetic Algorithm for Power Ultrasound Transducer.

Dual-frequency ultrasounds have demonstrated significant potential in augmenting thermal ablation efficiency for tumor treatment. Ensuring proper impedance matching between the dual-frequency transducer and the power amplifier system is imperative for equipment safety. This paper introduces a novel dual-frequency impedance matching network utilizing L-shaped topology and employing a genetic algorithm to compute component values. Implementation involved an adjustable capacitor and inductor network to achieve dual-frequency matching. Subsequently, the acoustic parameters of the dual-frequency HIFU transducer were evaluated before and after matching, and the effects of ultrasound thermal ablation with and without matching were compared. The proposed dual-frequency impedance matching system effectively reduced the standing wave ratio at the two resonance points while enhancing transmission efficiency. Thermal ablation experiments with matching circuits showed improved temperature rise efficiencies at both frequencies, resulting in an expanded ablation zone. The dual-frequency impedance matching method significantly enhances the transmission efficiency of the dual-frequency ultrasound system at two operational frequencies, thereby ensuring equipment safety. It holds promising prospects for application in dual-frequency ultrasound treatment.

Thermal ablation for multifocal papillary thyroid microcarcinoma: a systematic review and meta-analysis.

Clinical studies have indicated the potential safety and efficacy of thermal ablation (TA) in treating multifocal papillary thyroid microcarcinoma (MPTMC). However, a comprehensive systematic evaluation of its effectiveness was still lack. PubMed, EMBASE and Cochrane Library databases were systematically searched for studies published until October 23, 2023, that reported on the effectiveness of thermal ablation in the management of MPTMC. Data extraction and methodological quality assessment were independently conducted by two reviewers following the guidelines outlined in the PRISMA. This systematic review and meta-analysis identified 389 tumors in 169 patients from four studies. After treatment with different TA, the combined rate of complete disappearance of MPTMC was 92.8% [95% confidence interval (CI): 68.2-100] and the combined rate of overall complications was 4.4% [95% CI: 1.5-8.5]. During the follow-up period, local tumor recurrence was observed in only 2 patients with a combined rate of 0.2% [95% CI: 0.0-2.6]; lymph node metastasis (LNM) was observed in 3 patients with a combined rate of 1.2% [95% CI: 0-4.1]. Additionally, 6 patients developed new PTMC. It is noteworthy that no patients were observed to develop distant metastases during the follow-up period, and no patients had delayed surgery after underwent ablation. For patients grappling with MPTMC, TA emerges as an excellent approach for achieving localized tumor control. Nonetheless, achieving favorable outcomes necessitates stringent inclusion criteria and a profound level of expertize.

Novel nanoparticle CS-C60-Fe3O4 magnetically induces tissue-specific aggregation and enhances thermal ablation of hepatocellular carcinoma

Metallofullerenes are an important type of metallic nanomaterial with promising applications in several medical fields. Thermal ablation, including radiofrequency ablation (RFA) and microwave ablation (MWA), is an important treatment strategy for advanced hepatocellular carcinoma (HCC). The thermal expansion of fullerenes makes them good adjuncts to thermal ablation treatment of HCC. In this study, we used an innovative method of emulsification and cross-linking to produce CS-C60-Fe3O4 (Chitosan-C60-Fe3O4) nanoparticles, which have the advantages of uniform particle size and high bioavailability, as a kind of novel nano-pharmaceutical. The CS-C60-Fe3O4 nanoparticles were prepared by the cross-linking reaction from chitosan–acetic acid solution, Fe3O4 nanoparticles by Fe2SO4·7H2O and FeCl3·6H2O, and C60. The average particle size of CS-C60-Fe3O4 was 194.3 nm. Because CS-C60-Fe3O4 is magnetic, it can achieve specific and tissue aggregation in HCC tumor tissues. Moreover, compared with normal soluble C60 (EL35-C60), CS-C60-Fe3O4 prolonged the retention time of C60 in the blood of mice. CS-C60-Fe3O4 alone is not cytotoxic to cultured cells or tumor tissues, but when combined with thermal ablation strategies (RFA and MWA), it significantly upregulates the antitumor effects of thermal ablation on HCC tissues, that is, it acts as a sensitiser to thermal ablation. In the presence of thermal ablation, CS-C60-Fe3O4 interfered with iron metabolism in HCC cells and induced ferroptosis of HCC cells in the tumor tissues. These results not only expand our understanding of metallofullerenes but also provide additional options for the treatment of advanced HCC.

Effectiveness and advantages of ablative method of surgical removal of focies of verrucous leukoplakia of the oral mucosa with dental diode laser

The article presents clinical and diagnostic aspects of leukoplakia of the oral mucosa and red border of the lips and approaches to the treatment of the verrucous form of leukoplakia. The effectiveness of laser thermal ablation and adhesive balm with magnetic polymers, hexethidine, cytylpyridinium chloride and hyaluronic acid has been shown, which opens up new possibilities in the treatment of this pathology with minimal risk of complications.

A Systematic Study on the Processing Strategy in Femtosecond Laser Scribing via a Two-Temperature Model.

Balancing quality and productivity, especially deciding on the optimal matching strategy for multiple process parameters, is challenging in ultrashort laser processing. In this paper, an economical and new processing strategy was studied based on the laser scribing case. To reveal the temperature evolution under the combination of multiple process parameters in the laser scribing process, a two-temperature model involving a moving laser source was developed. The results indicated that the peak thermal equilibrium temperature between the electron and lattice increased with the increase in the laser fluence, and the temperature evolution at the initial position, influenced by subsequent pulses, was strongly associated with the overlap ratio. The thermal ablation effect was strongly enhanced with the increase in laser fluence. The groove morphology was controllable by selecting the overlap ratio at the same laser fluence. The removal volume per joule (i.e., energy utilization efficiency) and the removal volume per second (i.e., ablation efficiency) were introduced to analyze the ablation characteristics influenced by multiple process parameters. The law derived from statistical analysis is as follows; at the same laser fluence with the same overlap ratio, the energy utilization efficiency is insensitive to changes in the repetition rate, and the ablation efficiency increases as the repetition rate increases. As a result, a decision-making strategy for balancing quality and productivity was created.

Effectiveness of Thermal Ablation for Renal Cell Carcinoma after Prior Partial Nephrectomy

BackgroundRepeat partial nephrectomy (PN) for tumors recurring in the ipsilateral kidney is associated with surgical complexity and a higher rate of complications. ObjectiveTo evaluate the local oncologic efficacy of thermal ablation (TA) for renal cell carcinoma (RCC) in the ipsilateral kidney following PN. Design, setting, participationWe included patients who underwent ablation for renal tumors in the ipsilateral kidney after PN between January 2005 and December 2019. Demographics, tumor size, procedural details, complications, pathology, local oncologic outcomes, and survival outcomes are described. Outcome measurements and statistical analysisThe procedural, pathologic, and oncologic outcomes are described. Survival rates were estimated using the Kaplan-Meier method. Results and limitationsA total of 66 patients (46 male and 20 female) with a median age of 62 yr (interquartile range [IQR] 52–69) met our inclusion criteria. In these patients, 74 TA procedures were performed for 86 lesions (median tumor size 1.9 cm, IQR 1.6–2.5). Radiofrequency ablation and cryoablation accounted for 60 (81%) and 14 (19%) procedures, respectively. Three patients (3.7%) had Clavien-Dindo grade III complications. Of 65 lesion biopsies, 62 (95.5%) were diagnostic. The most common subtype was clear cell RCC (n = 37). The median imaging follow-up duration was 60 mo (IQR 43–88). Recurrence in the ablation zone occurred for four lesions (4.6%) at a median of 6.9 mo (IQR 6.4–10.7). The rates of overall, recurrence-free, and disease-free survival were 93.1%, 94.4%, and 65.6% at 5 yr, and 71.6%, 94.4%, and 60.1% at 10 yr, respectively. Limitations include the retrospective design and the lack of a control group. ConclusionsTA is effective for the treatment of RCC in the ipsilateral kidney following PN. Patient summaryHeat treatment to remove tumor tissue is an effective option for small kidney masses recurring after partial kidney removal for cancer. Long-term follow-up data revealed that this treatment resulted in low recurrence and complication rates.

Thermal/ultrasound-triggered release of liposomes loaded with Ganoderma applanatum polysaccharide from microbubbles for enhanced tumour ablation

The effectiveness of thermal ablation for the treatment of liver tumours is limited by the risk of incomplete ablation, which can result in residual tumours. Herein, an enhancement strategy is proposed based on the controlled release of Ganoderma applanatum polysaccharide (GAP) liposome–microbubble complexes (GLMCs) via ultrasound (US)-targeted microbubble destruction (UTMD) and sublethal hyperthermic (SH) field. GLMCs were prepared by conjugating GAP liposomes onto the surface of microbubbles via biotin–avidin linkage. In vitro, UTMD promotes the cellular uptake of liposomes and leads to apoptosis of M2-like macrophages. Secretion of arginase-1 (Arg-1) and transforming growth factor-beta (TGF-β) by M2-like macrophages decreased. In vivo, restriction of tumour volume was observed in rabbit VX2 liver tumours after treatment with GLMCs via UTMD in GLMCs + SH + US group. The expression levels of CD68 and CD163, as markers of tumour-associated macrophages (TAMs) in the GLMCs + SH + US group were reduced in liver tumour tissue. Decreased Arg-1, TGF-β, Ki67, and CD31 factors related to tumour cell proliferation and angiogenesis was evident on histological analysis. In conclusion, thermal/US-triggered drug release from GLMCs suppressed rabbit VX2 liver tumour growth in the SH field by inhibiting TAMs, which represents a potential approach to improve the effectiveness of thermal ablation.

Endovenous Thermal Ablation for Treatment of Symptomatic Saphenous Veins-Does the Body Weight Matter?

This study aimed to examine whether body weight may affect the effectiveness and safety of endovenous thermal ablation (ETA) for the treatment of symptomatic varicose veins. This retrospective single-center cohort study analyzed the outcomes and patient demographic data with a focus on the body weight of all patients who had ETA of symptomatic varicose veins between September 2017 and October 2020. A total of 1178 treated truncal veins from 636 patients were analyzed. The mean ± standard deviation body mass index (BMI) was 25.5 ± 4.9. In 2.3% of cases, the patients were underweight (BMI < 18.5), 31.0% were overweight (BMI > 25), and 16.6% were obese (BMI > 30). Complete truncal occlusion was observed 1 year post intervention in 97.6-100% and patients were satisfied or very satisfied in 96.2-100% across BMI groups. Pain was low but significantly higher in the patients with obesity 6 weeks post intervention (visual analog scale 0.84 ± 1.49) and a higher infection rate was observed in the patients with obesity (n = 4/132; 3.0%). No significant association was observed between BMI and bleeding or thromboembolic events. Patients with obesity experienced prolonged pain and more infections after ETA, but ETA for varicose vein treatment remains effective and safe, independent of the patient's BMI.

Effectiveness and Safety of Percutaneous Treatment in Lesions Suggestive of Thyroid Cancer (Bethesda V and VI-T1aN0M0) Compared to Surgical Treatment: Systematic Review and Meta-Analysis.

Thyroid nodules are common entities, with 5% malignancy. Differentiated thyroid cancer represents 90% of thyroid malignancies, with papillary carcinoma being the most common. Management is generally surgical; among its complications are injury to the recurrent laryngeal and superior laryngeal nerve, causing hoarseness, postsurgical hypoparathyroidism, hypothyroidism, and pain. Other noninvasive percutaneous interventions of thermal ablation such as microwave, radiofrequency, or laser incur lower costs and could be an option for treatment. To determine the effectiveness and safety of thermal ablation in lesions suspected of thyroid cancer (Bethesda V and VI/T1aN0M0) compared to surgical treatment. Systematic review/meta-analysis of observational studies and clinical trials. Database search includes MEDLINE/PUBMED, Embase, Scopus, Scielo, and BVS/LILACS. Studies on patients over 18 years of age with lesions suspicious of thyroid cancer were included. A total of 10 studies were obtained, with 2939 patients: 1468 subjected to thermal ablation and 1471 to surgery. Regarding effectiveness, no differences were found in local recurrence [relative risk (RR) 1.17 (95% CI 0.69-1.99)] and cervical lymph node metastasis [RR 0.76 (95% CI 0.43-1.36)]. Regarding safety, infection [RR 0.29 (95% CI 0.05-1.74)], hematoma [RR 0.57 (95% CI 0.17-1.94)], and transient hoarseness [RR 0.77 (95% CI 0.39-1.51)] were evaluated, without difference. However, permanent hoarseness had significant differences in favor of thermal ablation [RR 0.29 (95% CI 0.11-0.75)]. Thermal ablation for the treatment of T1aN0M0 papillary thyroid carcinoma is equally effective when compared to surgical techniques and offers a better safety profile, particularly in permanent hoarseness.

Immunomodulatory Effects of Endoscopic Ultrasound-Guided Thermal Ablation in Patients with Pancreatic Ductal Adenocarcinoma.

Immunological consequences of endoscopic ultrasound (EUS)-local thermal ablation (LTA) for pancreatic ductal adenocarcinoma (PDAC) have not been extensively assessed. We aimed to explore EUS-LTA effects on the systemic immune response in PDAC. Peripheral blood was collected from 10 treatment-naïve patients with borderline resectable and locally advanced PDAC, randomly allocated to Nab-paclitaxel plus Gemcitabine chemotherapy (CT-arm, n = 5) or EUS-LTA with HybridTherm Probe plus CT (HTP + CT-arm, n = 5). Twenty healthy donors were included as controls. Flow-cytometry and multiplex assays were used to profile immune cell subsets and measure serum cytokines/chemokines, respectively. At baseline, PDAC patients showed increased circulating monocytes and lower circulating lymphocytes and CD19+ B cells counts compared to healthy controls. After 4 months, CT induced decrease of B regulatory cells, CD4+ cytotoxic T cells and IL-1β. The addition of EUS-HTP to CT selectively decreased the serum levels of APRIL/TNFSF13 as well as T regulatory cells, total, classic and inflammatory monocytes. Serum levels of APRIL/TNFSF13 and total, classic and inflammatory monocytes counts at baseline were associated with worse overall survival. EUS-HTP has the potential to selectively impact on immune cells and cytokines associated with poor outcomes in PDAC.

Non-contact bacterial identification and decontamination based on laser-induced breakdown spectroscopy.

As a new kind of modern military biological weapon, bacterial agents pose a serious threat to the public health security of human beings. Existing bacterial identification requires manual sampling and testing, which is time-consuming, and may also introduce secondary contamination or radioactive hazards during decontamination. In this paper, a non-contact, nondestructive and "green" bacterial identification and decontamination technology based on laser-induced breakdown spectroscopy (LIBS) is proposed. The principal component analysis (PCA) combined with support vector machine (SVM) based on radial basis kernel function is used to establish the classification model of bacteria, and the two-dimensional decontamination test of bacteria is carried out using laser-induced low-temperature plasma combined with a vibration mirror. The experimental results show that the average identification rate of the seven types of bacteria, including Escherichia coli, Bacillus subtilis, Pseudomonas fluorescens, Bacillus megatherium, Pseudomonas aeruginosa, Bacillus thuringiensis and Enterococcus faecalis reaches 98.93%, and the corresponding true positive rate, precision, recall and F1-score reaches 0.9714, 0.9718, 0.9714 and 0.9716, respectively. The optimal decontamination parameters are laser defocusing amount of -50mm, laser repetition rate of 15-20kHz, scanning speed of 150mm/s and number of scans of 10. In this way, the decontamination speed can reach 25.6mm2/min, and the inactivation rates for both Escherichia coli and Bacillus subtilis are higher than 98%. In addition, it is confirmed that the inactivation rate of plasma is 4 times higher than that of thermal ablation, meaning that the decontamination ability of LIBS mainly relies on the plasma rather than the thermal ablation effect. The new non-contact bacterial identification and decontamination technology does not require sample pretreatment, and can quickly identify bacteria in situ and decontaminate the surfaces of precision instruments, sensitive materials, etc., which has potential application value in modern military, medical and public health fields.

Effects of thermal ablation on thyroid function in patients with thyrotoxicosis.

Effects of thermal ablation on thyroid function in patients with thyrotoxicosis.

Enabling Chemo-Immunotherapy with HIFU in Canine Cancer Patients.

High intensity focused ultrasound (HIFU) is a promising non-invasive technique for treating solid tumors using thermal and histotripsy-based mechanical ablation. However, its clinical significance in different tumor types is not fully understood. To assess its therapeutic efficacy and immunomodulatory properties, we compared HIFU thermal ablation and histotripsy ablation in dogs with spontaneous tumors. We also evaluated the ability of non-ablative HIFU-based mild hyperthermia (40-45 ºC) to improve Doxorubicin delivery and immunomodulation. Our results showed that HIFU thermal ablation induced tumor remission in the majority of treated patients over 60days, while histotripsy achieved partial response to stable disease persistence. The adverse effects of thermal ablation were minor to moderate, while histotripsy exposures were relatively well-tolerated. Furthermore, we observed a correlation between HIFU-therapeutic response and serum anti-tumor cytokine profiles and the presence of functionally active cytotoxic immune cells in patients. Similarly, Doxorubicin-treated patients showed improved drug delivery, efficacy, and anti-tumor immune responses with HIFU hyperthermia. In conclusion, our study demonstrates that depending on the tumor type and treatment parameters, HIFU treatments can enable tumor growth control, immune activation, and chemotherapy in veterinary patient. These findings have significant clinical implications and highlight the potential of HIFU as a promising cancer treatment approach.

AB-452672-3 PRE-CLINICAL PULSED-FIELD ABLATION (PFA) USING A SINGLE-SHOT CIRCULAR LINEAR ABLATION CATHETER FOR PV ISOLATION

Pulsed field ablation (PFA) is becoming the preferred energy treatment for pulmonary vein (PV) isolation. PFA application appears safe and effective and shortens procedure time. A circular linear ablation catheter may have advantages for single-shot delivery of PFA for PV isolation. To evaluate the feasibility of pusled field ablation for PV isolation with a circular linear ablation catheter. The Fiore™ catheter (EP Frontiers S.p.A., Italy; Figure) has two unique features: (1) an over the wire anchor and (2) an ablation element with linear electrodes. The anchor is positioned in the PV and guides the Circular Linear Ablation (CLA). The CLA can deliver PFA from a customized generator. Optimization of PFA parameters was conducted with a potato model in a saline bath by testing various energy pulses with bipolar and biphasic energy (500-1000 volts, pulse duration of 10-100 μs, interpulse pause of 10-400 μs, with a changing number of repetitions). The goal was to create circular ablations with a minimal depth of 3-4 mm. Following energy application images were acquired acutely and 18-24 hours after. Porcine in vivo testing (n=5 swine under general anaesthesia) with a deflectable sheath, evaluated PFA application at the left and right superior pulmonary vein, superior vena cava, and lateral wall of the right atrium with histopathology. In vitro ablations with three separate pulse trains demonstrated circular lesions with a diameter of up to 40 mm that were visible hours after the energy delivery. Average cross section of the circular lesions revealed an average depth of 3.2 mm with a surface width of 36 mm (Figure). Four applications (vs eight), from linear electrodes resulted in the most optimal and controlled circular lesions with central sparing and no off-target tissue destruction. Under fluoroscopic guidance, all positions in left and right atria, were easily accessed in all 5 animals (Figure). During PFA delivery, minimal skeletal muscle contraction was observed, without thermal ablation effect. Histopathology examination revealed acute changes in the atrial muscle structure. Chronic animal testing is ongoing to provide optimization of pulse trains and electrode to electrode sequencing to allow precise measurements of the PFA lesions depth. Following lesion optimization in an in vitro model, we demonstrate feasibility of delivering reproducible single-shot circumferential PFA lesions using a unique designed circular linear ablation catheter.