Статті в журналах: "Catheter tip contact force"

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Shah, Dipen. "Evolution of Force Sensing Technologies." Arrhythmia & Electrophysiology Review 6, no. 2 (2017): 75. http://dx.doi.org/10.15420/aer.2017.8.2.

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In order to improve the procedural success and long-term outcomes of catheter ablation techniques for atrial fibrillation (AF), an important unfulfilled requirement is to create durable electrophysiologically complete lesions. Measurement of contact force (CF) between the catheter tip and the target tissue can guide physicians to optimise both mapping and ablation procedures. Contact force can affect lesion size and clinical outcomes following catheter ablation of AF. Force sensing technologies have matured since their advent several years ago, and now allow the direct measurement of CF between the catheter tip and the target myocardium in real time. In order to obtain complete durable lesions, catheter tip spatial stability and stable contact force are important. Suboptimal energy delivery, lesion density/contiguity and/or excessive wall thickness of the pulmonary vein-left atrial (PV-LA) junction may result in conduction recovery at these sites. Lesion assessment tools may help predict and localise electrical weak points resulting in conduction recovery during and after ablation. There is increasing clinical evidence to show that optimal use of CF sensing during ablation can reduce acute PV re-conduction, although prospective randomised studies are desirable to confirm long-term favourable clinical outcomes. In combination with optimised lesion assessment tools, contact force sensing technology has the potential to become the standard of care for all patients undergoing AF catheter ablation.

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Shah, Dipen. "Evolution of Force Sensing Technologies." Arrhythmia & Electrophysiology Review 6, no. 2 (2017): 75. http://dx.doi.org/10.15420/aer.2017:8:2.

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In order to improve the procedural success and long-term outcomes of catheter ablation techniques for atrial fibrillation (AF), an important unfulfilled requirement is to create durable electrophysiologically complete lesions. Measurement of contact force (CF) between the catheter tip and the target tissue can guide physicians to optimise both mapping and ablation procedures. Contact force can affect lesion size and clinical outcomes following catheter ablation of AF. Force sensing technologies have matured since their advent several years ago, and now allow the direct measurement of CF between the catheter tip and the target myocardium in real time. In order to obtain complete durable lesions, catheter tip spatial stability and stable contact force are important. Suboptimal energy delivery, lesion density/contiguity and/or excessive wall thickness of the pulmonary vein-left atrial (PV-LA) junction may result in conduction recovery at these sites. Lesion assessment tools may help predict and localise electrical weak points resulting in conduction recovery during and after ablation. There is increasing clinical evidence to show that optimal use of CF sensing during ablation can reduce acute PV re-conduction, although prospective randomised studies are desirable to confirm long-term favourable clinical outcomes. In combination with optimised lesion assessment tools, contact force sensing technology has the potential to become the standard of care for all patients undergoing AF catheter ablation.

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Bickel, Karen, Thorsten Lewalter, Johannes Fischer, Christine Baumgartner, Petra Hoppmann, Klaus Tiemann, and Clemens Jilek. "Value of Mini Electrodes for Mapping Myocardial Arrhythmogenic Substrate—The Influence of Tip-to-Tissue Angulation and Irrigation Flow on Signal Quality." Journal of Vascular Diseases 1, no. 1 (August 3, 2022): 3–12. http://dx.doi.org/10.3390/jvd1010002.

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Background: The use of mini electrodes with a small surface and narrow electrode-to-electrode spacing is believed to lead to a higher electrical resolution. Until now, the effects of tip-to-tissue contact, angulation, and irrigation on signal quality and morphology are unknown. Methods: The beating heart of an open-chest pig was examined while controlling the angulation and contact between the catheter tip and myocardial tissue, as well as the irrigation of the catheter tip. The mini electrodes were mounted onto commercially available 8 mm non-irrigated and 4 mm irrigated tip catheters. Different electrode interconnections, angulations, contact forces, and irrigation flow were analyzed and compared to signals recorded from conventional electrodes. Results: A total of 63 electrode samples of 21 defined, stable settings, each lasting 30 s, were analyzed. (1) Tissue contact of mini electrodes was given as soon as the conventional tip electrode showed tissue contact. (2) Angulation of the tip-to-tissue contact showed a trend towards changes in the integral of signals derived from mini electrodes, and no significant changes were seen in signals derived from conventional or mini electrodes. (3) Irrigation flow surrounding the mini electrodes did not influence signals derived from mini electrodes, whereas conventional electrodes showed signals with a longer duration under higher irrigation. Conclusion: Mini electrodes are robust to contact force and irrigation flow regarding signal quality, whereas signals of conventional electrodes are affected by irrigation flow, leading to substantial changes in signal duration and kurtosis. Signals of mini electrodes are sensitive to local electrical changes because of a high local resolution.

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Page, Stephen P., and Mehul Dhinoja. "SmartTouch™ – The Emerging Role of Contact Force Technology in Complex Catheter Ablation." Arrhythmia & Electrophysiology Review 1 (2012): 59. http://dx.doi.org/10.15420/aer.2012.1.59.

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Novel technologies have been developed recently to assess contact between the ablation catheter and the underlying tissue in an attempt to improve safe and effective lesion delivery. The most recently developed technology is the SmartTouch™ catheter which is an open irrigated-tip catheter integrated within the CARTO 3 3D mapping system. In this review we consider the role of contact force technology, evaluate the published data and discuss the potential applications of this novel technology.

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Deubner, N., H. Greiss, E. Akkaya, A. Berkowitsch, S. Zaltsberg, C. W. Hamm, M. Kuniss, and T. Neumann. "Clinical experience with contact-force and flexible-tip ablation catheter designs." Journal of Interventional Cardiac Electrophysiology 47, no. 1 (March 31, 2016): 75–82. http://dx.doi.org/10.1007/s10840-016-0128-3.

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Karkowski, Grzegorz, Marcin Kuniewicz, Andrzej Ząbek, Edward Koźluk, Maciej Dębski, Paweł T. Matusik, and Jacek Lelakowski. "Contact Force-Sensing versus Standard Catheters in Non-Fluoroscopic Radiofrequency Catheter Ablation of Idiopathic Outflow Tract Ventricular Arrhythmias." Journal of Clinical Medicine 11, no. 3 (January 25, 2022): 593. http://dx.doi.org/10.3390/jcm11030593.

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Background: Adequate contact between the catheter tip and tissue is important for optimal lesion formation and, in some procedures, it has been associated with improved effectiveness and safety. We evaluated the potential benefits of contact force-sensing (CFS) catheters during non-fluoroscopic radiofrequency catheter ablation (NF-RFCA) of idiopathic ventricular arrhythmias (VAs) originating from outflow tracts (OTs). Methods: A group of 102 patients who underwent NF-RFCA (CARTO, Biosense Webster Inc., Irvine, CA, USA) of VAs from OTs between 2014 to 2018 was retrospectively analyzed. Results: We included 52 (50.9%) patients in whom NF-RFCA was performed using CFS catheters and 50 (49.1%) who were ablated using standard catheters. Arrhythmias were localized in the right and left OT in 70 (68.6%) and 32 (31.4%) patients, respectively. The RFCA acute success rate was 96.1% (n = 98) and long-term success during a minimum 12-month follow-up (mean 51.3 ± 21.6 months) was 85.3% (n = 87), with no difference between CFS and standard catheters. There was no difference in complications rate between CFS (n = 1) and standard catheter (n = 2) ablations. Conclusions: There is no additional advantage of CFS catheters use over standard catheters during NF-RFCA of OT-VAs in terms of procedural effectiveness and safety.

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Paulsen, Benjamin Alexander, Hannes Schwenke, Jakob Seemann, Peter Schramm, Georg Männel, and Philipp Rostalski. "Towards Test Bench for Aspiration Catheters in Realistic Evaluation Scenarios." Current Directions in Biomedical Engineering 8, no. 2 (August 1, 2022): 185–88. http://dx.doi.org/10.1515/cdbme-2022-1048.

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Abstract Aspiration catheters play an important role in mechanical thrombectomy in interventional neuroradiology as they provide support for stent retrievers or are increasingly used separately for contact aspiration. To evaluate the performance of different aspiration catheters in terms of suction force, most current studies rely on manual measurement methods or the suction force is not measured close to the aspiration catheter tip. Moreover, there is currently no standardized method that records measurements digitally and with high temporal resolution. To overcome these challenges, we propose a new test bench that simulates a dedicated aspiration scenario and takes measurements close to the aspiration catheter tip. To meet the requirements, a simplified vascular phantom, a pressure sensor and a simplified clot model were implemented in the prototype. To demonstrate the applicability of the prototype, two commonly used aspiration catheters were evaluated. The obtained measurements show that it is possible to perform standardized comparisons between aspiration catheters from different manufacturers as well as different aspiration pumps and aspiration tubings and their combinations. The developed prototype overcomes the still widely used manual and semimanual and thus error prone measurement methods for the evaluation of vacuum based thrombectomy systems.

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Bunch, T. Jared. "Excessive contact force can overcome irrigated tip catheter benefits during atrial fibrillation ablation." Journal of Cardiovascular Electrophysiology 29, no. 2 (December 14, 2017): 236–38. http://dx.doi.org/10.1111/jce.13391.

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Perna, Francesco, E. Kevin Heist, Stephan B. Danik, Conor D. Barrett, Jeremy N. Ruskin, and Moussa Mansour. "Assessment of Catheter Tip Contact Force Resulting in Cardiac Perforation in Swine Atria Using Force Sensing Technology." Circulation: Arrhythmia and Electrophysiology 4, no. 2 (April 2011): 218–24. http://dx.doi.org/10.1161/circep.110.959429.

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Kluzik, Anna, Hanna Tomczak, Marek Nowicki, Tomasz Koszel, Alicja Bartkowska-Śniatkowska, Krzysztof Kusza, and Małgorzata Grześkowiak. "Atomic force microscopy and scanning electron microscopy as alternative methods of early identification of pathogens causing catheter-related bloodstream infections of patients in ICU." Postępy Higieny i Medycyny Doświadczalnej 76, no. 1 (January 1, 2022): 157–64. http://dx.doi.org/10.2478/ahem-2022-0010.

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Abstract Introduction Vascular catheters are an indispensable element of the therapy of patients in intensive care. Their use is associated with the possibility of complications, including infectious. According to various sources, the incidence of catheter-related bloodstream infections (CRBSIs) ranges from 0.1 to 22.7 per 1,000 catheter days. Materials and Methods The central venous catheter tip culture samples were collected from 24 patients with suspected catheter-related bloodstream infection, from three intensive care units (ICUs). The results of microscopic examinations: atomic force microscope (AFM) and scanning electron microscope (SEM) were compared with the results of microbiological analysis of the central venous catheter tip and blood collected from the catheter. Results The microscopic examination and microbiological analysis of both the blood and central venous catheter samples confirmed the presence of microorganisms in 16 cases (double positive result). Our study was conducted in a short period of time (up to 6 hours) and it gave an initial answer to the question about the type of microorganisms colonising the central venous catheter. In one patient the infection was not caused by removal of the central venous catheter. However, not all results were fully consistent within the two diagnostic methods. The colonisation of the central venous catheter with Pseudomonas aeruginosa and Staphylococcus epidermidis was microbiologically confirmed, but it was not confirmed by the microscopic examination of the sample collected from patient No. 20. However, the examination enabled preliminary assessment of the microorganism colonising the catheter, which may have caused the blood infection. It cannot be ruled out that Pseudomonas aeruginosa bacilli were grown on the catheter that came into contact with blood from another source of infection, e.g. the respiratory, nervous or urinary systems. Information on the presence of cocci-shaped bacteria forming characteristic clusters or rods may enable initial diagnosis of catheter-related bloodstream infection if it is accompanied by typical clinical symptoms. Alternative diagnostics also provides valuable information on the presence of biofilm, which is a factor hindering the body’s response to infection and penetration of antibiotics. Conclusions Our pilot study presents new diagnostic possibilities of microscopic imaging with the atomic force microscope (AFM) and scanning electron microscope (SEM) to identify pathogens on routinely used disposable medical devices, such as the central venous catheter. On the other hand, this range of diagnostics reveals the potential to constantly improve medical materials which come into direct contact with patients’ tissues. It is important to create a database of microscopic images, which would be a repeatable diagnostic pattern and fully correlated with the results of microbiological analysis, because it would facilitate initial quick diagnosis of a potential CRBSI.

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Cercenelli, Laura, Barbara Bortolani, and Emanuela Marcelli. "CathROB: A Highly Compact and Versatile Remote Catheter Navigation System." Applied Bionics and Biomechanics 2017 (2017): 1–13. http://dx.doi.org/10.1155/2017/2712453.

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Several remote catheter navigation systems have been developed and are now commercially available. However, these systems typically require specialized catheters or equipment, as well as time-consuming operations for the system set-up. In this paper, we present CathROB, a highly compact and versatile robotic system for remote navigation of standard tip-steerable electrophysiology (EP) catheters. Key features of CathROB include an extremely compact design that minimizes encumbrance and time for system set-up in a standard cath lab, a force-sensing mechanism, an intuitive command interface, and functions for automatic catheter navigation and repositioning. We report in vitro and in vivo animal evaluation of CathROB. In vitro results showed good accuracy in remote catheter navigation and automatic repositioning (1.5 ± 0.6 mm for the left-side targets, 1.7 ± 0.4 mm for the right-side targets). Adequate tissue contact was achieved with remote navigation in vivo. There were no adverse events, including absence of cardiac perforation or cardiac damage, indicative of the safety profile of CathROB. Although further preclinical and clinical studies are required, the presented CathROB system seems to be a promising solution for an affordable and easy-to-use remote catheter navigation.

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Khoshnam, Mahta, Allan C. Skanes, and Rajni V. Patel. "Modeling and Estimation of Tip Contact Force for Steerable Ablation Catheters." IEEE Transactions on Biomedical Engineering 62, no. 5 (May 2015): 1404–15. http://dx.doi.org/10.1109/tbme.2015.2389615.

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Yip, Michael C., Jake A. Sganga, and David B. Camarillo. "Autonomous Control of Continuum Robot Manipulators for Complex Cardiac Ablation Tasks." Journal of Medical Robotics Research 02, no. 01 (February 26, 2017): 1750002. http://dx.doi.org/10.1142/s2424905x17500027.

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Continuum manipulators enable minimally-invasive surgery on the beating heart, but the challenges involved in manually controlling the manipulator’s tip position and contact force with the tissue result in failed procedures and complications. The objective of this work is to achieve autonomous robotic control of a continuum manipulator’s position and force in a beating heart model. We present a model-less hybrid control approach that regulates the tip position/force of manipulators with unknown kinematics/mechanics, under unknown constraints along the manipulator’s body. The algorithms estimate the Jacobian in the presence of heartbeat disturbances and sensor noise in real time, enabling closed-loop control. Using this model-less control approach, a robotic catheter autonomously traced clinically relevant paths on a simulated beating heart environment while regulating contact force. A gating procedure is used to tighten the treatment margins and improve precision. Experimental results demonstrate the capabilities of the robot ([Formula: see text][Formula: see text]mm–[Formula: see text][Formula: see text]mm tracking error) while user demonstrations show the difficulty of manually performing the same task ([Formula: see text][Formula: see text]mm–[Formula: see text][Formula: see text]mm tracking error). This new, robotically-enabled contiguous ablation method could reduce ablation path discontinuities, improve consistency of treatment, and therefore improve clinical outcomes.

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Pak, Hui‐Nam, Je‐Wook Park, Song‐Yi Yang, Hee Tae Yu, Jae‐Sun Uhm, Boyoung Joung, Moon‐Hyoung Lee, and Tae‐Hoon Kim. "A mesh‐type flexible tip catheter vs a contact force catheter for catheter ablation of atrial fibrillation: A prospective nonrandomized 1:1 matched study." Journal of Cardiovascular Electrophysiology 31, no. 6 (April 22, 2020): 1279–88. http://dx.doi.org/10.1111/jce.14484.

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MORI, Koji, Kazuto TAKASHIMA, Shinji KANEMURA, Hirokazu MURATA, Naoki TOMA, Takanori SANO, Yasuyuki UMEDA, Hidenori SUZUKI, and Takashi SAITO. "2F47 Study on catheter and guidewire simulation for intravacular surgery : Estimation for contact force of guidewire tip." Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 2014.26 (2014): 519–20. http://dx.doi.org/10.1299/jsmebio.2014.26.519.

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Duytschaever, Mattias, Mark O’Neill, and Martin Martinek. "Increasing the Single-Procedure Success Rate of Pulmonary Vein Isolation." Arrhythmia & Electrophysiology Review 6, no. 4 (2017): 217. http://dx.doi.org/10.15420/aer.2017.38/1.

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To improve the single-procedural success and long-term outcomes of catheter ablation techniques for AF, there is a need for durable, contiguous and transmural lesions encircling the pulmonary veins (PV). Measurement of contact force (CF) between the catheter tip and the target tissue can optimise ablation procedures. A new approach to obtain single-procedure durable PV isolation (PVI) using the latest CF technology combined with the CARTO VISITAG™ Module with Ablation Index (Biosense Webster) has been shown in small studies to almost eliminate recurrence of paroxysmal AF at 1-year follow up and to make PVI procedures more reproducible. The use of a standardised workflow is expected to increase the reproducibility of results and to increase the efficiency of PVI procedures.

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Zaltieri, Martina, Greta Allegretti, Carlo Massaroni, Emiliano Schena, and Filippo Maria Cauti. "Fiber Bragg Grating Sensors for Millimetric-Scale Temperature Monitoring of Cardiac Tissue Undergoing Radiofrequency Ablation: A Feasibility Assessment." Sensors 20, no. 22 (November 13, 2020): 6490. http://dx.doi.org/10.3390/s20226490.

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Radiofrequency ablation (RFA) is the most widely used technique for the treatment of cardiac arrhythmias. A variety of factors, such as the electrode tip shape, the force exerted on the tissue by the catheter and the delivered power, combine to determine the temperature distribution, and as consequence, the lesion shape and size. In this context, being able to know the temperature reached in the myocardium during the RFA can be helpful for predicting the lesion dimensions to prevent the occurrence of undesired tissue damage. The catheters used so far in such procedures provide single-point temperature measurements within the probe (by means of embedded thermocouples or thermistors), so no information regarding the temperature changes occurring in myocardial tissues can be retrieved. The aim of this study was to assess the feasibility of fiber Bragg grating sensors (FBGs) to perform multi-point and millimetric-scale temperature measurements within myocardium subjected to RFA. The assessment has been performed on ex vivo porcine myocardium specimens undergoing RFA. Data show the feasibility of the proposed solution in providing spatial temperature distribution within the myocardial tissue during the entire RFA. These high-resolved measurements may allow reconstructing the temperature distribution in the tissue. This study lays the foundations for the implementation of 3D thermal maps to investigate how the supplied power, treatment time, force of contact and irrigation flow of the catheter influence the thermal effects within the tissue.

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Meshkova, M., and A. Doronin. "Analysis of Complications in 1000 Consecutive Radiofrequency Catheter Ablations of Atrial Fibrillation." Ukrainian Journal of Cardiovascular Surgery, no. 2 (43) (June 18, 2021): 67–71. http://dx.doi.org/10.30702/ujcvs/21.4306/m009067-071/844-037-08.

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Introduction. In patients with drug-refractory symptomatic atrial fibrillation (AF), radiofrequency catheter ablation has become the main treatment option. Despite advances in technology and experience, the incidence of complications for this procedure reported by researchers still varies. In the USA, irrigated catheters are used nearly always, mostly with contact force sensing. We used conventional catheters. The aim. To analyze the complications in 1000 consecutive radiofrequency catheter ablations of atrial fibrillation. Results and discussion. Non-irrigated 4 mm tip ablation catheters and two venous punctures were used. In total, 32 (3.2%) complications were observed. Pericardial tamponade was observed in 6 cases (0.6%), pericardial effusion in 7 (0.7%), pericardial puncture without effusion in 1 (0.1%), pericarditis in 1 (0.1%), complete atrioventricular (AV) block in 2 (0.2%), transient AV block in 1 (0.1%), stroke in 2 (0.2%), diaphragm paresis with pneumonia in 1 (0.1%), femoral artery aneurysm in 6 (0.6%), femoral hematoma requiring blood transfusion in 2 (0.2%), arteriovenous fistula in 2 (0.2%), hematuria in 1 (0.1%). Similar frequency of iatrogenic AV block was reported in the literature. There were 26 (3.4%) complications during 794 primary procedures. After 206 repeated procedures, we observed 2 femoral hematomas, 2 femoral artery aneurysms, 1 arteriovenous fistula and 1 complete AV block – a total of 6 (2.9%) complications. In several reports the incidence of life-threatening complications was lower than that in our study. However, the total number of complications in our group is at the level of the best results, despite the fact that we do not use irrigated catheters, esophageal temperature probes and endovascular ultrasound probes. Conclusions. The technique that we use is as safe as other methods of AF radiofrequency catheter ablation.

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Costea, Alexandru, Laura Goldstein, Sonia Maccioni, Iftekhar Kalsekar, and Rahul Khanna. "Real-world outcomes comparison among adults with atrial fibrillation undergoing catheter ablation with a contact force porous tip catheter versus a second-generation cryoballoon catheter: a retrospective analysis of multihospital US database." BMJ Open 10, no. 8 (August 2020): e035499. http://dx.doi.org/10.1136/bmjopen-2019-035499.

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ObjectiveTo compare real-world clinical and economic outcomes among atrial fibrillation (AF) patients undergoing cardiac ablation with the contact force-sensing porous tip THERMOCOOL SMARTTOUCH SF (STSF) catheter versus the Arctic Front Advance Cryoballoon (AFA-CB) catheter.DesignRetrospective, observational cohort study.SettingPremier Healthcare Database (PHD), between 1 September 2016 and 30 June 2018.ParticipantsPatients with AF (≥18 years) were included if they had an index ablation procedure performed using the STSF catheter or AFA-CB catheter at a US hospital that consistently provided inpatient and outpatient data to PHD in the 12-month preindex period. Using 1:1 propensity score matching, patient groups were matched on study covariates.Primary and secondary outcome measuresCost, length of stay (LOS), readmissions, direct current cardioversion (DCCV) and reablation outcomes were compared between matched cohorts of STSF and AFA-CB patients.ResultsA total of 3015 patients with AF met the study criteria, of which 1720 had ablation using the STSF catheter and 1295 had ablation using the AFA-CB catheter. In the propensity-matched sample, patients receiving ablation with the STSF catheter had ~17% lower total costs (US$23 096 vs US$27 682, p≤0.0001) and ~27% lower supply costs (US$10 208 vs US$13 816, p≤0.0001) versus patients receiving ablation with the AFA-CB catheter. A significantly lower likelihood of 4-month to 6-month cardiovascular-related readmission (OR 0.460, 95% CI 0.220 to 0.959) was associated with the STSF catheter versus the AFA-CB catheter. No significant differences in LOS, room and board cost, 4-month to 6-month all-cause and AF-related readmissions, DCCV and reablation were observed among technologies. Sensitivity analysis restricting patient sample by provider ablation volume demonstrated similar results.ConclusionLower index ablation total and supply costs were observed among patients with AF undergoing cardiac catheter ablation using the STSF catheter versus the AFA-CB catheter.

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Cha, Hyo-Jeong, Byung-Ju Yi, and Jong Yun Won. "An assembly-type master–slave catheter and guidewire driving system for vascular intervention." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 231, no. 1 (December 22, 2016): 69–79. http://dx.doi.org/10.1177/0954411916679328.

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Current vascular intervention inevitably exposes a large amount of X-ray to both an operator and a patient during the procedure. The purpose of this study is to propose a new catheter driving system which assists the operator in aspects of less X-ray exposure and convenient user interface. For this, an assembly-type 4-degree-of-freedom master–slave system was designed and tested to verify the efficiency. First, current vascular intervention procedures are analyzed to develop a new robotic procedure that enables us to use conventional vascular intervention devices such as catheter and guidewire which are commercially available in the market. Some parts of the slave robot which contact the devices were designed to be easily assembled and dissembled from the main body of the slave robot for sterilization. A master robot is compactly designed to conduct insertion and rotational motion and is able to switch from the guidewire driving mode to the catheter driving mode or vice versa. A phantom resembling the human arteries was developed, and the master–slave robotic system is tested using the phantom. The contact force of the guidewire tip according to the shape of the arteries is measured and reflected to the user through the master robot during the phantom experiment. This system can drastically reduce radiation exposure by replacing human effort by a robotic system for high radiation exposure procedures. Also, benefits of the proposed robot system are low cost by employing currently available devices and easy human interface.

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Plenge, Tobias, Jan-Hendrik van den Bruck, Jakob Lüker, Arian Sultan, and Daniel Steven. "Porous tip contact force–sensing catheters for pulmonary vein isolation: performance in a clinical routine setting." Journal of Interventional Cardiac Electrophysiology 57, no. 2 (July 19, 2019): 251–59. http://dx.doi.org/10.1007/s10840-019-00591-2.

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Takigawa, Masateru, Masahiko Goya, Junji Yamaguchi, MIHO NEGISHI, Takashi Ikenouchi, Tasuku Yamamoto, Takatoshi Shigeta, et al. "PO-04-199 CHARACTERISTICS AND SAFETY OF A NOVEL CONTACT-FORCE SENSING IRRIGATED CATHETER WITH A FLEXIBLE TIP WITH LASER-CUT KERFS." Heart Rhythm 20, no. 5 (May 2023): S572—S573. http://dx.doi.org/10.1016/j.hrthm.2023.03.1215.

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Chinitz, Larry A., Daniel P. Melby, Francis E. Marchlinski, Craig Delaughter, Robert S. Fishel, George Monir, Anshul M. Patel, et al. "Safety and efficiency of porous-tip contact-force catheter for drug-refractory symptomatic paroxysmal atrial fibrillation ablation: results from the SMART SF trial." EP Europace 20, FI_3 (August 9, 2017): f392—f400. http://dx.doi.org/10.1093/europace/eux264.

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Nair, Devi G., Martin Martinek, Byron J. Colley, Sri Sundaram, Saumya Sharma, Gustavo X. Morales, Philipp Sommer, et al. "MP-453081-1 PAROXYSMAL ATRIAL FIBRILLATION ABLATION WITH THE FIRST FLEXIBLE TIP RADIOFREQUENCY CATHETER INCORPORATING CONTACT FORCE SENSING: TACTIFLEX AF IDE TRIAL RESULTS." Heart Rhythm 20, no. 5 (May 2023): S126. http://dx.doi.org/10.1016/j.hrthm.2023.03.459.

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OKUMURA, YASUO, SUSAN B. JOHNSON, T. JARED BUNCH, BENHUR D. HENZ, CHRISTINE J. O'BRIEN, and DOUGLAS L. PACKER. "A Systematical Analysis ofIn VivoContact Forces on Virtual Catheter Tip/Tissue Surface Contact during Cardiac Mapping and Intervention." Journal of Cardiovascular Electrophysiology 19, no. 6 (June 2008): 632–40. http://dx.doi.org/10.1111/j.1540-8167.2008.01135.x.

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Maurer, Tilman, Laura Rottner, Hisaki Makimoto, Bruno Reissmann, Christian-H. Heeger, Christine Lemes, Thomas Fink, et al. "The best of two worlds? Pulmonary vein isolation using a novel radiofrequency ablation catheter incorporating contact force sensing technology and 56-hole porous tip irrigation." Clinical Research in Cardiology 107, no. 11 (May 8, 2018): 1003–12. http://dx.doi.org/10.1007/s00392-018-1270-y.

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Anjo, Naofumi, Shiro Nakahara, Yasuo Okumura, Yuichi Hori, Koichi Nagashima, Takaaki Komatsu, Akiko Hayashi, Sayuki Kobayashi, Yoshihiko Sakai, and Isao Taguchi. "Impact of catheter tip-tissue contact on three-dimensional left atrial geometries: Relationship between the external structures and anatomic distortion of 3D fast anatomical mapping and high contact force guided images." International Journal of Cardiology 222 (November 2016): 202–8. http://dx.doi.org/10.1016/j.ijcard.2016.07.186.

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Fichtner, Stephanie, Tilko Reents, Sonia Ammar, Verena Semmler, Susanne Kathan, Roger Dillier, Alexandra Buiatti, Gabriele Hessling, and Isabel Deisenhofer. "Pulmonary vein isolation using new technologies to improve ablation lesion formation: Initial results comparing enhanced catheter tip irrigation (Surround Flow®) with contact force measurement (Smarttouch®)." Indian Pacing and Electrophysiology Journal 15, no. 3 (May 2015): 152–57. http://dx.doi.org/10.1016/j.ipej.2015.07.004.

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Shuang, Tian, Lingcong Kong, Fuyu Cheng, and Xinhua Wang. "Prevalence, Predictors and Mechanisms of Steam Pops in Ablation Index-Guided High-Power Pulmonary Vein Isolation." Journal of Cardiovascular Development and Disease 9, no. 12 (December 7, 2022): 441. http://dx.doi.org/10.3390/jcdd9120441.

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Despite the good cooling effect of the contact-force porous catheter, the risk of steam pops (SP) remains one of the major concerns in high-power circumferential pulmonary vein isolation (CPVI). This study aimed to investigate the prevalence, predictors and possible mechanisms of SPs in CPVI. Patients experiencing SPs in de novo high-power CPVI were 1:3 matched by non-SP patients with gender, age (±5 years) and left atrial diameter (LAD) (±5 mm) to compare the ablation parameters of SP and non-SP lesions. Catheter tip displacement (Tipdisp) was compared between “edge-of-ridge” and “PV-side-of-ridge” placement at anterior and roof segments of the left pulmonary vein (PV). SPs occurred in 11 (1.57%) of 701 patients, including 6 at the antero-superior left PV, 2 at the roof, 1 at the postero-superior left PV, 1 at the bottom left PV and 1 at the antero-superior aspect of the right PV. There was significantly shorter RF delivery duration (13.9 ± 6.3 vs. 23.3 ± 6.0 s), greater Δimpedance (17.6 ± 6.7 vs. 6.7 ± 4.1 Ω) and lower ablation index (357.7 ± 68.8 vs. 430.2 ± 30.7) in SP patients than those in non-SP patients. Δimpedance >12 Ω during ablation could predict SP occurrence. Tipdisp was greater in “PV-side-of-ridge” than that in “edge-of -ridge” placement (3.2 ± 1.6 mm vs. 2.0 ± 0.8 mm) at antero-superior and roof segments of the left PV. The prevalence of SP was 1.57% in high-power CPVI procedures, with the most common site at the antero-superior segment of the left PV. Δimpedance was a significant predictor of SP occurrence. “PV-side-of-ridge” ablation at antero-superior and roof segments of left PV might predispose to SP occurrence due to excessive tissue coverage.

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Masnok, Kriengsak, and Nobuo Watanabe. "Relationship of Catheter Contact Angle and Contact Force with Contact Area on the Surface of Heart Muscle Tissue in Cardiac Catheter Ablation." Cardiovascular Engineering and Technology 12, no. 4 (March 15, 2021): 407–17. http://dx.doi.org/10.1007/s13239-021-00529-8.

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Abstract Purpose The aims of this study were to develop an experimental procedure for setting the catheter angle with respect to the surface of the heart muscle and the catheter contact force and to investigate the catheter contact area on the heart muscle as a function of catheter contact angle and force. Methods Visualization tests were performed for 5 contact angles (0°, 30°, 45°, 60°, and 90°) and 8 contact forces (2, 4, 6, 10, 15, 20, 30, and 40 gf). Each experiment was repeated 6 times with 2 different commercially available catheter tips. Results The morphology of the contact area was classified into rectangular, circular, ellipsoidal, and semi-ellipsoidal. The correlation between contact force and contact area was a logarithmic function; increasing contact force was associated with increased contact area. At the same contact force, the correlation between contact angle and contact area was inverse; decreasing contact angle was associated with a corresponding increase in contact area. Conclusion Both the catheter contact angle and contact force substantially impact the contact area and morphology in catheter ablation procedures.

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Cheng, Guo Dong, and Xiao Jing Yang. "Nano-Contact Force Calculation Method of Different Tip Radius of Curvature and the Specimen Surface of AFM." Applied Mechanics and Materials 723 (January 2015): 952–57. http://dx.doi.org/10.4028/www.scientific.net/amm.723.952.

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Atomic Force Microscope (AFM) works by the force between the probe tip and specimen surface. The nanocontact force between the probe tip and specimen surface has an important influence on the detection surface. Base on the analysis of the working principle of the AFM and nanocontact force calculation model, according to Hamaker assumptions, using continuum method established the theoretical contact force model of the AFM tip. the contact force calculation methods of contact pressure in process has been obtained. The variation of the force between the probe tip and specimen surface has been found by calculation model and programming calculation of Matlab. Provide the basis for improving the accuracy of an atomic force microscope surface inspection and error analysis

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Yaeger, Kurt, Annabelle Iserson, Paul Singh, Jacob Wolf, Ester Vidal, Thomas Oxley, Anthony B. Costa, and Johanna T. Fifi. "A technical comparison of thrombectomy vacuum aspiration systems." Journal of NeuroInterventional Surgery 12, no. 1 (July 4, 2019): 72–76. http://dx.doi.org/10.1136/neurintsurg-2019-014929.

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IntroductionImproved functional outcomes after mechanical thrombectomy for emergent large vessel occlusion depend on expedient reperfusion after clinical presentation. Device technology has improved substantially over the years, and several commercial options exist for both large-bore aspiration catheters and suction pump systems.ObjectiveTo compare various vacuum pumps and examine the aspiration forces they generate as well as the force of catheter tip detachment from an artificial thrombus.MethodsUsing an artificial thrombus made from polyvinyl alcohol gel, we tested various mechanical characteristics of commercially available suction pumps, including the Penumbra Jet Engine, Penumbra Max, Stryker Medela AXS, Microvention Gomco, and a 60 cc syringe. Both aspiration pressure and tip force generated were analyzed. Subsequently, a cohort of thrombectomy catheters were assessed using the Penumbra Jet Engine to determine tip forces generated on an artificial thrombus. One-way analysis of variance was used to assess statistical significance.ResultsThe Penumbra Jet Engine system generated both the highest maximum aspiration pressures (28.8 inches Hg) and the highest tip force (23.68 grams force (gf)) on an artificial thrombus, with statistical significance compared with the other pump systems. Using the Jet Engine, the largest-bore catheter was associated with the highest tip force (32.12 gf). The overall correlation coefficient between catheter inner diameter and tip force was 0.98.ConclusionsThe Penumbra Jet Engine pump generates significantly higher vacuum pressures and tip forces than the other commercially available aspiration pump systems. Furthermore, catheters with a larger inner diameter generate higher tip suction forces on aspiration. Whether these mechanical features lead to improved clinical outcomes is yet to be determined.

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Lally, Frank, Mitra Soorani, Timothy Woo, Sanjeev Nayak, Changez Jadun, Ying Yang, John McCrudden, Shailesh Naire, Iris Grunwald, and Christine Roffe. "In vitro experiments of cerebral blood flow during aspiration thrombectomy: potential effects on cerebral perfusion pressure and collateral flow." Journal of NeuroInterventional Surgery 8, no. 9 (August 28, 2015): 969–72. http://dx.doi.org/10.1136/neurintsurg-2015-011909.

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BackgroundMechanical thrombectomy with stent retriever devices is associated with significantly better outcomes than thrombolysis alone in the treatment of acute ischemic stroke. Thrombus aspiration achieves high patency rates, but clinical outcomes are variable. The aim of this study was to examine the effect of different suction conditions on perfusate flow during aspiration thrombectomy.MethodsA computational fluid dynamics model of an aspiration device within a patent and occluded blood vessel was used to simulate flow characteristics using fluid flow solver software. A physical particulate flow model of a patent vessel and a vessel occluded by thrombus was then used to visualize flow direction and measure flow rates with the aspiration catheter placed 1–10 mm proximal of the thrombus, and recorded on video.ResultsThe mathematical model predicted that, in a patent vessel, perfusate is drawn from upstream of the catheter tip while, in an occluded system, perfusate is drawn from the vessel proximal to the device tip with no traction on the occlusion distal of the tip. The in vitro experiments confirmed the predictions of this model. In the occluded vessel aspiration had no effect on the thrombus unless the tip of the catheter was in direct contact with the thrombus.ConclusionsThese experiments suggest that aspiration is only effective if the catheter tip is in direct contact with the thrombus. If the catheter tip is not in contact with the thrombus, aspirate is drawn from the vessels proximal of the occlusion. This could affect collateral flow in vivo.

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Natale, Andrea, Vivek Y. Reddy, George Monir, David J. Wilber, Bruce D. Lindsay, H. Thomas McElderry, Charan Kantipudi, et al. "Paroxysmal AF Catheter Ablation With a Contact Force Sensing Catheter." Journal of the American College of Cardiology 64, no. 7 (August 2014): 647–56. http://dx.doi.org/10.1016/j.jacc.2014.04.072.

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Froehler, Michael T. "Comparison of Vacuum Pressures and Forces Generated by Different Catheters and Pumps for Aspiration Thrombectomy in Acute Ischemic Stroke." Interventional Neurology 6, no. 3-4 (2017): 199–206. http://dx.doi.org/10.1159/000475478.

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Background: Direct aspiration thrombectomy is an increasingly utilized technique in endovascular stroke treatment that relies on vacuum and suction force to remove the clot. This report assesses the pressures and forces generated by different catheters and pumps. Methods: Vacuum pressures were measured using a vacuum gauge for several catheters (Stryker Catalyst6, Penumbra Ace 064, Medtronic Arc 061, and Penumbra 041) and pumps (Penumbra pump, 60-mL syringe, and the ASPIRE device). Suction forces were calculated based on pressure and catheter tip size (force = area × pressure). Vacuum pressures and forces were also assessed with a coaxial microcatheter (Rebar 18; inner diameter = 0.021 inches), mimicking a combined aspiration and stent retriever approach. Results: All catheters transmitted similar vacuum pressures, but suction force was proportionate to catheter tip area. Pump vacuum pressures were also similar, although the Penumbra pump (mean -25.63 inches Hg [inHg]) was slightly weaker than the syringe and the ASPIRE device (-27.04 and -27.58 inHg, respectively; p < 0.001, two-way ANOVA). A coaxial microcatheter lowered the mean vacuum pressure by only 1.2 inHg (p = 0.005), though it would theoretically create a very significant reduction in suction force if partially blocking the aspiration catheter tip area. Conclusions: All catheters transmit similar vacuum pressure, but the suction force on the clot is stronger with larger catheter tips. Coaxial microcatheters will have a minimal impact on suction force as long as they are proximal to the aspiration catheter tip. Currently available thrombectomy suction devices, including the Penumbra pump, the ASPIRE handheld pump, and the 60-mL syringe, all develop similar vacuum pressures.

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Bessière, Francis, Christopher Zikry, Lena Rivard, Katia Dyrda, and Paul Khairy. "Contact force with magnetic-guided catheter ablation." EP Europace 20, suppl_2 (May 1, 2018): ii1—ii4. http://dx.doi.org/10.1093/europace/euy006.

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Sweetman, Adam, Nicolas Goubet, Ioannis Lekkas, Marie Paule Pileni, and Philip Moriarty. "Nano-contact microscopy of supracrystals." Beilstein Journal of Nanotechnology 6 (May 29, 2015): 1229–36. http://dx.doi.org/10.3762/bjnano.6.126.

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Background: Highly ordered three-dimensional colloidal crystals (supracrystals) comprised of 7.4 nm diameter Au nanocrystals (with a 5% size dispersion) have been imaged and analysed using a combination of scanning tunnelling microscopy and dynamic force microscopy. Results: By exploring the evolution of both the force and tunnel current with respect to tip–sample separation, we arrive at the surprising finding that single nanocrystal resolution is readily obtained in tunnelling microscopy images acquired more than 1 nm into the repulsive (i.e., positive force) regime of the probe–nanocrystal interaction potential. Constant height force microscopy has been used to map tip–sample interactions in this regime, revealing inhomogeneities which arise from the convolution of the tip structure with the ligand distribution at the nanocrystal surface. Conclusion: Our combined STM–AFM measurements show that the contrast mechanism underpinning high resolution imaging of nanoparticle supracrystals involves a form of nanoscale contact imaging, rather than the through-vacuum tunnelling which underpins traditional tunnelling microscopy and spectroscopy.

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Beltrán, F. J. Espinoza, J. Muñoz-Saldaña, D. Torres-Torres, R. Torres-Martínez, and G. A. Schneider. "Atomic force microscopy cantilever simulation by finite element methods for quantitative atomic force acoustic microscopy measurements." Journal of Materials Research 21, no. 12 (December 2006): 3072–79. http://dx.doi.org/10.1557/jmr.2006.0379.

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Measurements of vibrational spectra of atomic force microscopy (AFM) microprobes in contact with a sample allow a good correlation between resonance frequencies shifts and the effective elastic modulus of the tip-sample system. In this work we use finite element methods for modeling the AFM microprobe vibration considering actual features of the cantilever geometry. This allowed us to predict the behavior of the cantilevers in contact with any sample for a wide range of effective tip-sample stiffness. Experimental spectra for glass and chromium were well reproduced for the numerical model, and stiffness values were obtained. We present a method to correlate the experimental resonance spectrum to the effective stiffness using realistic geometry of the cantilever to numerically model the vibration of the cantilever in contact with a sample surface. Thus, supported in a reliable finite element method (FEM) model, atomic force acoustic microscopy can be a quantitative technique for elastic-modulus measurements. Considering the possibility of tip-apex wear during atomic force acoustic microscopy measurements, it is necessary to perform a calibration procedure to obtain the tip-sample contact areas before and after each measurement.

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Dong, Mei, Mei Li, and Yan Zhang. "The Effect of Tip Materials on the Nanotribology with Atomic Force Microscope Technique." Applied Mechanics and Materials 723 (January 2015): 763–68. http://dx.doi.org/10.4028/www.scientific.net/amm.723.763.

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The effect of tip materials on the friction properties of silicon substrate was investigated by using atomic force microcopy (AFM). The roughness of the silicon wafer surface was characterized with silicon tip at tapping mode, and then the relationship between the friction force and normal force was obtained by silicon tip and silicon nitride tip at contact mode. The experimental results show that when the load exceeds a critical value, the friction coefficient with silicon tip increases from 0.17 to 0.37, which is due to the wear of the silicon tip; the friction coefficient with a hard silicon nitride tip increases from 0.25 to 0.5, which can only be attributed to the plastic deformation of silicon substrate. And the roughness of the silicon substrate can lead to an incomplete contact, which can influence the real contact area between the silicon nitride tip and silicon substrate.

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Al-Ahmad, Omar, Mouloud Ourak, Johan Vlekken, Eric Lindner, and Emmanuel Vander Poorten. "Three-dimensional catheter tip force sensing using multi-core fiber Bragg gratings." Frontiers in Robotics and AI 10 (March 9, 2023). http://dx.doi.org/10.3389/frobt.2023.1154494.

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Awareness of catheter tip interaction forces is a crucial aspect during cardiac ablation procedures. The most important contact forces are the ones that originate between the catheter tip and the beating cardiac tissue. Clinical studies have shown that effective ablation occurs when contact forces are in the proximity of 0.2 N. Lower contact forces lead to ineffective ablation, while higher contact forces may result in complications such as cardiac perforation. Accurate and high resolution force sensing is therefore indispensable in such critical situations. Accordingly, this work presents the development of a unique and novel catheter tip force sensor utilizing a multi-core fiber with inscribed fiber Bragg gratings. A customizable helical compression spring is designed to serve as the flexural component relaying external forces to the multi-core fiber. The limited number of components, simple construction, and compact nature of the sensor makes it an appealing solution towards clinical translation. An elaborated approach is proposed for the design and dimensioning of the necessary sensor components. The approach also presents a unique method to decouple longitudinal and lateral force measurements. A force sensor prototype and a dedicated calibration setup are developed to experimentally validate the theoretical performance. Results show that the proposed force sensor exhibits 7.4 mN longitudinal resolution, 0.8 mN lateral resolution, 0.72 mN mean longitudinal error, 0.96 mN mean lateral error, a high repeatability, and excellent decoupling between longitudinal and lateral forces.

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Blumfield, Amit, Jay Chudow, John D. Fisher, Luigi DiBiase, Kevin J. Ferrick, and andrew krumerman. "Abstract 15612: Force, Power, and Temperature Settings in Slow Pathway Modification Utilizing an Irrigated Force Sensing Ablation Catheter." Circulation 142, Suppl_3 (November 17, 2020). http://dx.doi.org/10.1161/circ.142.suppl_3.15612.

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Introduction: Atrioventricular node reentry tachycardia (AVNRT) ablation is typically performed with solid tip catheters set to temperature control (TC) mode. Radiofrequency (RF) output, tip temperature (T), and junctional rhythm response (JRR) during RF application have been well defined. JRR in an intermittent burst, sinus-junction-junction, or sinus-junction-sinus pattern is associated with successful modification of the AV nodal slow pathway (SP). Irrigated force-sensing catheters (IFSC) are often utilized for mapping and ablation of the SP. Despite this, parameters for IFSC used in TC mode resulting in JRR have not been well described. Hypothesis: Parameters predicting JRR and successful SP modification with IFSC include power (P), force (F), impedance drop (I), and target temperature (T). Methods: Consecutive patients that underwent electrophysiologic study and successful ablation of typical AVNRT with an IFSC were studied. Lesion parameters including P, T, F, time and I change were analyzed. Lesions producing JRR were considered efficacious. Independent T-Test and ANOVA were used to determine significance between the two groups (efficacious and non-efficacious lesions). Results: 296 lesions in 39 patients (age 52+/-14) were analyzed. All patients had successful SP modification without complication. Average F producing JRR was 8g, average T producing JRR was 41 o C, average I drop producing JRR was 9 Ohms, and average P producing JRR was 28W. Only RF lesion time was a significant predictor of JRR (p=0.009). (Table 1). Conclusions: Successful SP modification with IFSC was accomplished with catheter contact force as low as 2g. Lower average tip T, and lower average P settings compared to parameters typically used with solid tip catheters were observed. Parameters including P, F, T, and I change were not predictive of JRR. Additional studies controlling for catheter location while varying parameters are indicated.

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Gorantla, A., M. Alsaiqali, S. Sivakumar, J. Francois, L. Freytes-Santiago, A. Jallad, and A. Budzikowski. "Effectiveness of various radiofrequency ablation catheters in the treatment of typical atrial flutter." European Heart Journal 43, Supplement_2 (October 1, 2022). http://dx.doi.org/10.1093/eurheartj/ehac544.458.

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Abstract Introduction Although ablation of typical atrial flutter (AFL) can be easily achieved with radiofrequency energy (RF), there are no studies that compare effectiveness of different ablation catheters. Our study aimed to compare the effectiveness of various types of ablation catheters in the treatment of AFL. Methods We analysed patients with AFL who underwent RF ablation by a single operator at our institution. Successful ablation was evidenced by presence of bidirectional conduction block (trans-isthmus conduction time ≥130 ms, or doubling of baseline conduction time, or presence of double potentials ≥90ms). Logistic regression was used to compare success rate and linear regression to compare lesion time. Results Out of the 222 patients, only 6 patients did not meet success criteria (2.7%). Catheters used were 8 mm tip in 16 patients, internally irrigated (Chili II Boston Scientific) in 47 patients, externally irrigated (non-force sensing) catheters (CoolPath, Abbott) in 40 patients. Externally irrigated force sensing catheter (Tacticath, Abbott) was used with >10 gm of force and (LPLD) setting (30W-45°C-60 sec) in 50 patients, and high-power short duration (HPSD) setting (50W-43°C −12 sec,) in 70 patients. No complications were encountered. Catheter type had no statistically significant association with ablation success. In terms of lesion time, HPSD catheter statistically significantly shortened lesion time by 758.3s, [CI −1128.29, −388.35s] followed by LPLD by 419.0s [CI −808.49, −29.47s]. Table 1 shows the lesion time difference for the catheters used as compared with 8 mm tip. Conclusions Typical atrial flutter radiofrequency ablation procedure had a high success rate, not influenced by type of ablation catheter. Contact force ablation catheter on HPSD is associated with shorter total lesion time. Funding Acknowledgement Type of funding sources: None.

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Petras, A., M. Echeverria Ferrero, M. Leoni, J. M. Guerra, J. Jansson, and L. Gerardo-Giorda. "P2431Stay on the safe side: in-silico assessment of ablation protocols to prevent steam pops during radiofrequency ablation." European Heart Journal 40, Supplement_1 (October 1, 2019). http://dx.doi.org/10.1093/eurheartj/ehz748.0764.

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Abstract Background Steam pops (SP) are among the most serious complications of radiofrequency ablation (RFA) due to its potential to cause myocardial tear or tamponade. SP occur when the tissue overheats, causing its water content to transform into steam and explode. Ablation parameters are critical in order to obtain an optimal lesion size while avoiding the occurrence of SP. However, the interaction between ablation settings and the physical parameters that predispose to SP occurrence during irrigated RFA are not fully understood. Purpose To characterize regularly used ablation protocols by means of a computational model, in order to achieve optimal lesion size while avoiding SP occurrence. Methods The in-silico evaluation is performed using our previously developed computational irrigated RFA model. Our model takes into account the blood-saline interaction as well as the mechanical deformation of the tissue due to the contact with the catheter tip. We test the effects of applied power and contact force on two catheter tip designs (spherical and cylindrical) and two substrates, simulated human atrium and ventricle, during 30 sec applications. A fixed blood flow and catheter-tip saline irrigation (0.5m/s and 17mL/min, respectively) are considered. We simulate human tissue by using the biophysical, mechanical and physiological properties found in the literature. SP occurrence is predicted when the temperature within the tissue reaches 100°C. Results Based on the interaction of power and contact force, four risk maps are constructed encompassing the two catheter-tip designs and the two simulated tissues. The maps allow the identification of those ablation protocols (contact force and delivered power) that can potentially result on SP. They correspond to that area of critical temperature values where the temperature within the tissue reach the established criteria for SP occurrence. We also present the lesion size dimensions of ablation protocols that avoid the formation of steam pops. Conclusion Our results indicate that the applied power has a strong impact in the formation of SP for a cylindrical catheter, while a combination of contact force and power is important to avoid risks in the case of the spherical catheter tip. The tissue characteristics do not affect significantly the SP occurrence, in agreement with experimental literature. However, the resulting lesion size appears to be larger in the simulated human atrium in comparison to the simulated human ventricle. Acknowledgement/Funding BERC 2018-2021, SEV-2017-0718

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Nair, D., M. Martinek, J. Colley, S. Sundaram, S. Sharma, G. Morales, P. Sommer, et al. "Acute results of a novel flexible tip radiofrequency catheter incorporating contact force sensing." EP Europace 24, Supplement_1 (May 18, 2022). http://dx.doi.org/10.1093/europace/euac053.077.

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Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Abbott Background Catheter ablation is an established therapy for paroxysmal atrial fibrillation (PAF). The TactiFlex Ablation Catheter, Sensor-Enabled (TactiFlex SE) is a next-generation radiofrequency ablation catheter incorporating highly accurate fiber optics-based contact force sensing technology with a flexible, laser-cut tip. This is the first report of results from the TactiFlex IDE clinical study. Purpose To demonstrate that ablation with TactiFlex SE is safe and effective for the treatment of drug refractory, symptomatic PAF. Methods The TactiFlex IDE (NCT04356040) is a prospective, non-randomized, multi-center clinical study which enrolled 305 subjects worldwide in the main study. Enrollment in the main study began on June 26, 2020 and completed on June 8, 2021. Subjects underwent de novo Pulmonary Vein Isolation (PVI) and, if indicated, a Cavotricuspid Isthmus ablation (CTI line) for CTI-dependent atrial flutter. Results Acute procedural success was achieved in 98.6% (274/278) of the main study cohort who underwent an ablation procedure using the TactiFlex SE. First pass success, defined as isolation of all pulmonary veins (PVs) confirmed after a minimum 20 min waiting period was achieved in 89.6% (249/278) of subjects. This was a significant improvement versus the TactiSense IDE trial (TactiCath Ablation Catheter, Sensor-Enabled). Significant decreases were also seen in total procedure time (123 min [101.0, 163.5]), total PV ablation time (55.5 min [35.0, 81.0]), total fluoroscopy time (6.0 min [0.0, 13.0]) and irrigation fluid volume (450.0 mL [346.0, 636.0]) (values given as Median [Q1, Q3]), see FIGURE. All subjects have completed at least 90 days of follow-up. Only 2.6% (7/271) of subjects required a repeat procedure during the 90-day blanking period. The primary safety and effectiveness endpoints will be evaluated at 12-months. At 90 days, 4.3% (12/281) subjects had experienced a primary safety endpoint event. Conclusions The acute data from the TactiFlex IDE clinical study demonstrate safety and effectiveness of the TactiFlex SE catheter in the treatment of PAF. Ablation procedures performed using the next-generation TactiFlex SE catheter were shorter and had improved acute clinical effectiveness outcomes versus the TactiSense IDE. It is anticipated these results will also be reflected in the 12-month safety and effectiveness endpoints.

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Alfalahi, Hessa, Federico Renda, Conor Messer, and Cesare Stefanini. "Exploiting the instability of eccentric tube robots for distal force control in minimally invasive cardiac ablation." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, May 18, 2021, 095440622110075. http://dx.doi.org/10.1177/09544062211007524.

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While the dilemma of motion tracking and force control in beating-heart surgery is previously addressed using active control architectures and rigid robotic actuators, this work leverages the highly controllable mechanical properties of concentric tube robots for intelligent, design-based force control in minimally invasive cardiac ablation. Briefly, cardiac ablation is the conventional procedure for treating arrhythmia patients, by which exposing the diseased cardiac tissue to Radio-Frequency (RF) energy restores the normal heart rhythm. Yet, the procedure suffers low success rate due to the inability of existing flexible catheters to maintain a consistent, optimal contact force between the tip electrode and the tissue, imposing the need for future repeat surgeries upon disease recurrence. The novelty of our work lies in the development of a statically-balanced compliant mechanism composed of (1) distal bi-stable concentric tubes and (2) a compliant, torsional spring mechanism that provides torque at tubes proximal extremity, resulting in an energy-free catheter with a zero-stiffness tip. This catheter is expected to maintain surgical efficacy and safety despite the chaotic displacement of the heart, by naturally keeping the tip force at an optimal level, not less and not more than the surgical requirement. The presented experimental results of the physical prototype, reflect the feasibility of the proposed design, as well as the robustness of the formulated catheter mathematical models which were uniquely deployed in the selection of the optimal design parameters.

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Ramanna, H., J. L. Lloret, F. Zahwe, C. Porterfield, S. Trines, I. Djajadisastra, D. Gibson, et al. "P981Comparison of automark utilization and lesion metric target during paroxysmal atrial fibrillation ablation with a contact force-sensing ablation catheter: European and U.S. multicenter Experiences." EP Europace 22, Supplement_1 (June 1, 2020). http://dx.doi.org/10.1093/europace/euaa162.004.

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Abstract Background Accurate delivery of transmural lesion is associated with improved durability of pulmonary vein isolation and reduced reconduction. Lesion quality depends on multiple parameters such as radiofrequency power, tissue-catheter contact, duration of energy application, and catheter tip temperature. Consequently, energy delivery parameters vary based on individual operators’ preferences and procedural needs. Purpose To characterize and compare the utilization of automated lesion marking feature and lesion delivery parameters used during paroxysmal atrial fibrillation ablation performed with a magnetic sensor enabled contact force-sensing catheter across European and U.S. centers. Methods Procedural data were prospectively collected in clinical cases performed with a new magnetic sensor enabled, contact force ablation catheter within the first 6 months of use at participating centers in Europe and the U.S. Use of bidirectional CF catheters, steerable sheaths, automated lesion marking software and associated lesion delivery parameters during paroxysmal atrial fibrillation ablation were evaluated. Results A total of 149 cases across 37 centers in 11 European countries, and 112 cases across 31 U.S. centers were analyzed. A bidirectional contact force catheter (56.4% and 90.2%), a steerable sheath (65.8% and 69.6%), and the automated lesion marking module (77.9% and 90.2%) were used in most European and U.S. cases, respectively. The most commonly reported energy delivery parameters were: lesion index (LSI), Force-Time Integral (FTI), and time from European cases; LSI, average force, and FTI for U.S. cases (Table). Target LSI values were recorded for 126 cases in Europe and 34 in the U.S, ranging from 3 to 6. In anterior/roof segments, most common LSI target values for anterior/roof and posterior/inferior segments were 6 (42.9%) and 5 (51.2%) in Europe, and 5.5 (44.1%) and 5 (54.5%) in the U.S. PVI was confirmed with an average of 20.3 minutes waiting period (69.1%) for European cases and exit block (57.1%) in U.S. cases. First pass PVI were 67.1% and 74.4% for European and U.S. cases, respectively. Conclusion Energy delivery parameters and PVI confirmation method varied considerably by geography during paroxysmal atrial fibrillation ablation using the magnetic sensor enabled, contact force ablation catheter. Further study on efficacy implication on these differences in practice should be examined. Energy delivery parameters used Paroxysmal AF N LSI FTI Time Imp Drop Avg Force Other N/A Europe 149 44.0 % 13.4 % 7.0 % 6.0 % 2.4 % 1.0 % 26.2 % U.S. 112 31.2% 17.9 % 6.2 % 8.0 % 23.2 % 11.7 % 1.8 % Energy delivery parameters used in paroxysmal AF ablation in Europe and U.S.

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Wintgens, Lisette I. S., Martijn N. Klaver, Moniek Maarse, Stefan G. Spitzer, Anke Langbein, Martin J. Swaans, Vincent F. Van Dijk, et al. "Efficacy and safety of the GOLD FORCE multicentre randomized clinical trial: multielectrode phased radiofrequency vs. irrigated radiofrequency single-tip catheter with contact force ablation for treatment of symptomatic paroxysmal atrial fibrillation." EP Europace, July 19, 2021. http://dx.doi.org/10.1093/europace/euab168.

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Abstract Aims Pulmonary vein isolation (PVI) for atrial fibrillation (AF) has become increasingly safe and effective with the evolution of single-tip ablation catheters aided by contact force sensing (ST-CF) and single-shot devices such as the second-generation pulmonary vein ablation catheter (PVAC) Gold multi-electrode array. The multicentre randomized GOLD FORCE trial was conducted to evaluate non-inferiority of safety and efficacy of PVAC Gold PVI compared to ST-CF ablation for paroxysmal AF. Methods and results The primary efficacy endpoint documented AF recurrence ≥30 s was assessed by time-to-first-event analysis after a 90-day blanking period using repeated 7-day Holters. Secondary endpoints include acute success and procedural characteristics. Safety endpoints included procedural complications, stroke/transient ischaemic attack (TIA), tamponade, bleeding, and access site complications. Two hundred and eight patients underwent randomization and PVI (103 assigned to PVAC Gold, 105 to ST-CF). Acute success rates were 95% and 97% for PVAC Gold and ST-CF, respectively. At 12 months, AF recurrence was observed in 46.6% of the PVAC Gold group and in 26.2% of the ST-CF group [absolute efficacy difference 20.4% (95% confidence interval, CI 7.5–33.2%), hazard ratio 2.05 (95% CI 1.28–3.29), P = 0.003]. PVAC Gold had significantly shorter procedure and ablation times. Complication rates were 5.7% and 4.9% for PVAC Gold and ST-CF, respectively (P = 0.782). Conclusion In this multicentre randomized clinical trial, ablation with ST-CF and PVAC Gold ablation catheters non-inferiority for efficacy was not met. AF recurrence was significantly more frequent in the PVAC Gold group compared to single-tip contact force group. Both groups had similarly low rates of adverse events. PVAC Gold ablation had significantly shorter procedure and ablation times.

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Alken, Fares-Alexander, Katharina Scherschel, Ann-Kathrin Kahle, Mustafa Masjedi, and Christian Meyer. "Combined contact force and local impedance dynamics during repeat atrial fibrillation catheter ablation." Frontiers in Physiology 13 (October 13, 2022). http://dx.doi.org/10.3389/fphys.2022.1001719.

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Background: Optimal lesion formation during catheter-based radiofrequency current (RFC) ablation depends on electro-mechanical tip-tissue coupling measurable via contact force (CF) and local impedance (LI) monitoring. We aimed to investigate CF and LI dynamics in patients with previous atrial fibrillation (AF) ablation who frequently present with heterogenous arrhythmia substrate.Methods: Data from consecutive patients presenting for repeat AF or atrial tachycardia ablation using a novel open-irrigated single-tip ablation catheter were studied. RFC applications were investigated regarding CF, LI and the maximum LI drop (∆LI) for evaluation of ablation efficacy. ∆LI > 20 Ω was defined as a successful RFC application.Results: A total of 730 RFC applications in 20 patients were analyzed. Baseline CF was not associated with baseline LI (R = 0.06, p = 0.17). A mean CF < 8 g during ablation resulted in lower ∆LI (<8 g: 13 Ω vs. ≥ 8 g: 16 Ω, p < 0.001). Baseline LI showed a better correlation with ∆LI (R = 0.35, p < 0.001) compared to mean CF (R = 0.17, p < 0.001). Mean CF correlated better with ∆LI in regions of low (R = 0.31, p < 0.001) compared to high (R = 0.21, p = 0.02) and intermediate voltage (R = 0.17, p = 0.004). Combined CF and baseline LI predicted ∆LI > 20 Ω (area under the receiver operating characteristic curve (AUC) 0.75) better compared to baseline LI (AUC 0.72), mean CF (AUC 0.60), force-time integral (AUC 0.59) and local bipolar voltage (0.55).Conclusion: Combination of CF and LI may aid monitoring real-time catheter-tissue electro-mechanical coupling and lesion formation within heterogenous atrial arrhythmia substrate in patients with repeat AF or atrial tachycardia ablation.

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Sairaku, Akinori, Yukiko Nakano, Kazuyoshi Suenari, and Yasuki Kihara. "Abstract 15618: Anatomy Does Matter: The Relationship Between Catheter-Tissue Contact Force and Anatomical Variations of Left Atrium." Circulation 132, suppl_3 (November 10, 2015). http://dx.doi.org/10.1161/circ.132.suppl_3.15618.

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Background: Adequate catheter-to-myocardial contact force (CF) and catheter stability are important to create transmural lesions during catheter ablation of atrial fibrillation (AF). It is known that there are anatomical variations in left atrium (LA) and it is related to the outcome after the ablation. We tested any relationship between the CF and LA anatomical variations. Methods: Consecutive patients undergoing radiofrequency-based extensive encircling pulmonary vein (PV) isolation for the treatment of paroxysmal AF were dichotomized according to the LA anatomical variations; patients who had a PV-bifurcation region of LA ridge that was steep enough to enable a stable catheter-tip contact or a left common PV (group 1, the red arrows in Figure 1), or those who had neither (group 2, the blue arrows in Figure 1). The blinded operators carried out the procedure with the use of CARTO system, and the following VisiTag™ module setting was applied; a minimum time spent in an area of 5 seconds, a maximum distance the catheter has moved of 4mm, a force over time of 25%, and a minimum force of 10g. Low-CF tags was defined as ablation tags on CARTO map located at anterior aspect of left PVs that did not fulfill the pre-determined VisiTag™ criteria. The endpoints were the number of low-CF tags and freedom from AF 1 year after the ablation. Results: Patients in group 1 (n=31) had a smaller number of low-CF tags than those in group 2 (n=55, 2.8±2.1 vs. 5.9±3.8; p=0.013). Freedom from AF was more common in group 1 compared to group 2 (80.6% vs. 60%; p=0.04), and was independently associated with the number of low-CF of <3 (hazard ratio 2.4, confidence interval 1.12-6.87; p=0.026). Conclusions: Contact of the catheter-tip with the tissue may predict outcome after AF ablation, and it may depend on LA anatomical variations.

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van de Sande, Werner W. P. J., Awaz Ali, and Giuseppe Radaelli. "Design and Evaluation of a Passive Constant Force Mechanism for a Cardiac Ablation Catheter." Journal of Medical Devices 15, no. 2 (December 18, 2020). http://dx.doi.org/10.1115/1.4048911.

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Abstract Contact force management has been proven to have a positive effect on the outcome of cardiac ablation procedures. However, no method exists that allows maintaining a constant contact force within a required and effective range. This work aims to develop and evaluate such a constant force mechanism for use in an ablation catheter. A passive constant force mechanism was designed based on a tape loop. The tape loop consists of two tapered springs that work in parallel. A finite element analysis was carried out to verify the behavior and performance of the design. A design based on requirements for a constant force ablation tip showed an average force of about 7.8×10−2 N±8×10−3 N over 20 mm in simulation. A scaled prototype was built and evaluated to prove the validity of the concept; this prototype provides an average force of 1.3×10−1 N±1.6×10−2 N over 35 mm. The mechanism allows for controlled delivery of contact force within a desired and effective range. Based on these findings, it can be concluded that the approach is successful but needs to be optimized for future applications. Being able to control the delivery of contact force in a constant range may increase the effectivity of cardiac ablation procedures and improve clinical outcomes.

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