scholarly journals Comparing the Safety and Effectiveness of Dedicated Radiofrequency Transseptal Wires to Electrified Metal Guidewires

2021 ◽  
Author(s):  
Jeremiah Wasserlauf ◽  
Bradley Knight
Keyword(s):  
Thermal Imaging ◽  
Thermal Damage ◽  
Tissue Temperature ◽  
Transseptal Puncture ◽  
Rf Power ◽  
Output Level ◽  
Energy Delivery ◽  
Tissue Heating ◽  
Consistency Effect ◽  
Secondary Endpoints

Application of electrocautery to a metal guidewire can be used to perform transseptal puncture (TSP). Dedicated radiofrequency guidewires (RF) may represent a better alternative. This study compares safety and effectiveness of electrified guidewires to a dedicated RF wire. TSP was performed on porcine hearts using an electrified 0.014” or 0.032” guidewire under various power settings compared to TSP using a dedicated RF wire with 5W power. The primary endpoint was the number of attempts required to achieve TSP. Secondary endpoints included the rate of TSP failure, TSP consistency, effect of the distance between tip of the guidewire and the tip of the dilator, and effect of RF power output level. Qualitative secondary endpoints included tissue puncture defect appearance, thermal damage to the TSP guidewire or dilator, and tissue temperature using thermal imaging. The RF wire required 1.10 ± 0.47 attempts to cross the septum. The 0.014” electrified guidewire required 2.17 ± 2.36 attempts (2.0x higher than the RF wire; p<0.01), and the 0.032” electrified guidewire required 3.90 ± 2.93 attempts (3.5x higher than the RF wire; p<0.01). Electrified guidewires had a higher rate of TSP failure, larger defects, more tissue charring, higher temperatures, and greater tissue heating. Fewer RF applications were required to achieve TSP using a dedicated RF wire compared to an electrified guidewire. Smaller defects and lower tissue temperatures were also observed using the RF wire. Electrified guidewires required greater energy delivery and were associated with equipment damage and tissue charring.

Ocular surface temperature differences in glaucoma

2021 ◽  
pp. 112067212110237
Author(s):  
Ari Leshno ◽  
Ori Stern ◽  
Yaniv Barkana ◽  
Noa Kapelushnik ◽  
Reut Singer ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Thermal Imaging ◽  
Ocular Surface ◽  
Open Angle Glaucoma ◽  
Tissue Temperature ◽  
Body Temperatures ◽  
Current Thinking ◽  
Imaging Camera ◽  
The Mean ◽  
The Difference

Purpose: Accumulating evidence suggests that neuroinflammation and immune response are part of the sequence of pathological events leading to optic nerve damage in glaucoma. Changes in tissue temperature due to inflammation can be measured by thermographic imaging. We investigated the ocular surface temperature (OST) profile of glaucomatous eyes to better understand the pathophysiology of these conditions. Methods: Subjects diagnosed with glaucoma (primary open angle glaucoma [POAG] or pseudo exfoliation glaucoma [PXFG]) treated at the Sam Rothberg Glaucoma Center (11/2019–11/2020.) were recruited. Healthy subjects with no ocular disease served as controls. The Therm-App thermal imaging camera was used for OST acquisition. Room and body temperatures were recorded, and the mean temperatures of the medial cantus, lateral cantus, and cornea were calculated with image processing software. Results: Thermographic images were obtained from 52 subjects (52 eyes: 25 POAG and 27 PXFG) and 66 controls (66 eyes). Eyes with glaucoma had a significantly higher OST compared to controls (mean 0.9 ± 0.3°C, p < 0.005). The difference between the two groups remained significant after adjustment for age, sex, intraocular pressure (IOP) and room and body temperatures. Lens status and topical IOP-lowering medication did not significantly affect OST. A subgroup analysis revealed that the OST was higher among eyes with POAG compared to eyes with PXFG, but not significantly. Conclusions: Differences in the OST between glaucomatous and normal eyes strengthens current thinking that inflammation affects the pathophysiology of glaucoma. Longitudinal studies are warranted to establish the prognostic value of thermographic evaluations in these patients.

scholarly journals The Effect of Conductivity Changes on Temperature Rise During Irreversible Electroporation

2020 ◽  
Author(s):  
Amir Khorasani
Keyword(s):  
Electrical Conductivity ◽  
Cell Death ◽  
Electric Field ◽  
Electric Field Intensity ◽  
Thermal Damage ◽  
Pulse Sequence ◽  
Irreversible Electroporation ◽  
Tissue Temperature ◽  
Comsol Multiphysics ◽  
Simulation Results

Purpose: Irreversible electroporation is a physical process which is used for killing the cancer cells. The process that leads to cell death in this method is a unique process. Thermal damage does not exist in this process. However, the temperature of the tissue also increases during the electroporation. In this study, we aim to investigate the effect of conductivity changes on tissue temperature increase during the irreversible electroporation process. Materials and Methods: To perform simulations and solve equations, COMSOL MultiPhysics has been used. Standard electroporation pulse sequence (8 pulses with different electric field intensities) was used as a pulse sequence in the simulation. Results: During the electroporation process, the electrical conductivity and the temperature of the tissue were increased. Changes in the tissue temperature in the simulation with variable electrical conductivity are more than in the simulation with constant electrical conductivity during the electroporation process. This difference for pulses with more vigorous electric field intensity and points closer to the electrodes has been achieved more. Conclusion: To more accurately estimate and calculate the temperature and thermal damage inside the tissue during the irreversible electroporation process, it is suggested to consider the effect of conductivity changes during this process.

scholarly journals Evaluation of potential tissue heating during percutaneous drill-assisted bone sampling in an in vivo porcine study

2021 ◽  
Author(s):  
Stefan M. Niehues ◽  
Sefer Elezkurtaj ◽  
Keno K. Bresssem ◽  
Bernd Hamm ◽  
Christoph Erxleben ◽  
...  
Keyword(s):  
Thermal Damage ◽  
Critical Threshold ◽  
In Vivo Model ◽  
Bone Lesions ◽  
Bone Drilling ◽  
Tissue Quality ◽  
Tissue Heating ◽  
Bone Biopsies ◽  
Median Change

Abstract Background Minimally invasive, battery-powered drilling systems have become the preferred tool for obtaining representative samples from bone lesions. However, the heat generated during battery-powered bone drilling for bone biopsies has not yet been sufficiently investigated. Thermal necrosis can occur if the bone temperature exceeds a critical threshold for a certain period of time. Purpose To investigate heat production as a function of femur temperature during and after battery-powered percutaneous bone drilling in a porcine in vivo model. Methods We performed 16 femur drillings in 13 domestic pigs with an average age of 22 weeks and an average body temperature of 39.7 °C, using a battery-powered drilling system and an intraosseous temperature monitoring device. The standardized duration of the drilling procedure was 20 s. The bone core specimens obtained were embedded in 4% formalin, stained with haematoxylin and eosin (H&E) and sent for pathological analysis of tissue quality and signs of thermal damage. Results No significant changes in the pigs’ local temperature were observed after bone drilling with a battery-powered drill device. Across all measurements, the median change in temperature between the initial measurement and the temperature measured after drilling (at 20 s) was 0.1 °C. Histological examination of the bone core specimens revealed no signs of mechanical or thermal damage. Conclusion Overall, this preliminary study shows that battery-powered, drill-assisted harvesting of bone core specimens does not appear to cause mechanical or thermal damage.

Technological Advances in Minimally Invasive Radiofrequency Ablation of Cardiac Tissues

2010 ◽  
Vol 5 (2) ◽  
pp. e138-e146 ◽  
Author(s):  
Mark DiFrancesco ◽  
Chris Park ◽  
Keith E. Martin ◽  
Jason Glithero ◽  
Salvatore Privitera ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
Surgical Resection ◽  
Surgical Techniques ◽  
Low Complexity ◽  
Target Tissue ◽  
Tissue Impedance ◽  
Cardiac Tissues ◽  
Energy Delivery ◽  
Tissue Heating ◽  
Ablative Techniques

Ablative techniques have been sought in many circumstances as alternatives to surgical resection/incision. Besides being minimally invasive, potential benefits of ablation include greater speed and improved access to target tissue compared with other surgical techniques. There is a wide variety of ablation technologies currently in use for medical treatment. These include but are not limited to tissue heating by radiofrequency (RF) current, microwaves, laser, and high intensity ultrasound. RF is among the most heavily used because of its relatively low complexity and cost. Ablative techniques have proven to be viable alternatives to surgical resection/incision of tissue. Although there are other means of tissue heating besides RF, RF is the most commonly used technique in operating rooms because of the reliability of transmural lesions and the low complexity of the system. Optimal systems account for the heterogeneous nature of tissue and variations in tissue property through the ablation cycle. It is important to monitor and assure adequate energy delivery by selecting the appropriate configuration of devices. Energy delivery varies between the various generators and systems, some more responsive than others with relative to changes in tissue impedance that will affect the end results of the operation.

scholarly journals Modified Transseptal Puncture Technique in Challenging Septa: A Randomized Comparison to Conventional Technique

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Vikas Kataria ◽  
Benjamin Berte ◽  
Yves Vandekerckhove ◽  
Rene Tavernier ◽  
Mattias Duytschaever
Keyword(s):  
Primary Endpoint ◽  
Left Atrial ◽  
Median Number ◽  
Conventional Technique ◽  
Transseptal Puncture ◽  
Safety And Efficacy ◽  
Dose Area Product ◽  
Secondary Endpoints ◽  
Area Product ◽  
Pressure Failure

Background. Transseptal puncture (TSP) can be challenging. We compared safety and efficacy of a modified TSP technique (“mosquito” technique, MOSQ-TSP) to conventional TSP (CONV-TSP). Method. Patients undergoing AF ablation in whom first attempt of TSP did not result in left atrial (LA) pressure (failure to cross, FTC) were randomized to MOSQ-TSP (i.e., puncture of the fossa via a wafer-thin inner stylet) or CONV-TSP (i.e., additional punctures at different positions). Primary endpoint was LA access. Secondary endpoints were safety, time, fluoroscopic dose (dose-area product, DAP), and number of additional punctures from FTC to final LA access. Result. Of 384 patients, 68 had FTC (MOSQ-TSP, n=34 versus CONV-TSP, n=34). No complications were reported. In MOSQ-TSP, primary endpoint was 100% (versus 73.5%, p<0.002), median time to LA access was 72 s [from 37 to 384 s] (versus 326 s [from 75 s to 1936 s], p<0.002), mean DAP to LA access was 1778±2315 mGy/cm2 (versus 9347±10690 mGy/cm2, p<0.002), and median number of additional punctures was 2 [1 to 3] (versus 0, p<0.002). Conclusion. In AF patients in whom the first attempt of TSP fails, the “mosquito” technique allows effective, safe, and time sparing LA access. This approach might facilitate TSP in elastic, aneurysmatic, or fibrosed septa.

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