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Sample records for 2-french radiofrequency catheter

  1. Basic aspects of radiofrequency catheter ablation.

    PubMed

    Nath, S; DiMarco, J P; Haines, D E

    1994-10-01

    Radiofrequency (RF) catheter ablation has become the treatment of choice for many symptomatic cardiac arrhythmias. It is presumed that the primary cause of tissue injury by RF ablation is thermally mediated, resulting in a relatively discrete homogeneous lesion. The mechanism by which RF current heats tissue is resistive heating of a narrow rim (< 1 mm) of tissue that is in direct contact with the ablation electrode. Deeper tissue heating occurs as a result of passive heat conduction from this small region of volume heating. Lesion size is proportional to the temperature at the electrode-tissue interface and the size of the ablation electrode. Temperatures above 50 degrees C are required for irreversible myocardial injury, but temperatures above 100 degrees C result in coagulum formation on the ablation electrode, a rapid rise in electrical impedance, and loss of effective tissue heating. Lesion formation is also dependent on optimal electrode-tissue contact and duration of RF delivery. Newer developments in RF ablation include temperature monitoring, longer ablation electrodes coupled to high-powered RF generators, and novel ablation electrode designs.

  2. Anesthetic Management in Radiofrequency Catheter Ablation of Ventricular Tachycardia.

    PubMed

    Deng, Yi; Naeini, Payam S; Razavi, Mehdi; Collard, Charles D; Tolpin, Daniel A; Anton, James M

    2016-12-01

    Radiofrequency catheter ablation is increasingly being used to treat patients who have ventricular tachycardia, and anesthesiologists frequently manage their perioperative care. This narrative review is intended to familiarize anesthesiologists with preprocedural, intraprocedural, and postprocedural implications of this ablation. Ventricular tachycardia typically arises from structural heart disease, most often from scar tissue after myocardial infarction. Many patients thus affected will benefit from radiofrequency catheter ablation in the electrophysiology laboratory to ablate the foci of arrhythmogenesis. The pathophysiology of ventricular tachycardia is complex, as are the technical aspects of mapping and ablating these arrhythmias. Patients often have substantial comorbidities and tenuous hemodynamic status, necessitating pharmacologic and mechanical cardiopulmonary support. General anesthesia and monitored anesthesia care, when used for sedation during ablation, can lead to drug interactions and side effects in the presence of ventricular tachycardia, so anesthesiologists should also be aware of potential perioperative complications. We discuss variables that can help anesthesiologists safely guide patients through the challenges of radiofrequency catheter ablation of ventricular tachycardia.

  3. Radiofrequency catheter ablation for the management of cardiac tachyarrhythmias.

    PubMed

    Wood, M; Ellenbogen, K; Stambler, B

    1993-10-01

    Radiofrequency catheter ablation techniques allow for safe and highly effective curative therapy of a variety of cardiac dysrhythmias. The technique involves the delivery of a high-frequency, alternating electrical current through an intravascular catheter to sites of arrhythmogenic myocardium. This current induces resistive electrical heating of the tissue, resulting in discrete areas of myocardial destruction through coagulation and desiccation. Dysrhythmias most commonly treated with these techniques are atrioventricular nodal reentry and tachycardias related to accessory atrioventricular bypass tracts. For these dysrhythmias, success rates of 90% to 95% are achievable with a low (2% to 4%) risk of complications. Radiofrequency catheter ablation techniques also have been used to treat ventricular tachycardias, atrial flutter, ectopic atrial tachycardia, and sinus node reentry, albeit with lower success rates. These techniques are still evolving, alternate energy sources (such as microwave and laser) and improved catheter technology should enhance the technique's safety and efficacy for a wider range of dysrhythmias.

  4. Factors influencing lesion formation during radiofrequency catheter ablation.

    PubMed

    Eick, Olaf J

    2003-07-01

    In radiofrequency (RF) ablation, the heating of cardiac tissue is mainly resistive. RF current heats cardiac tissue and in turn the catheter electrode is being heated. Consequently, the catheter tip temperature is always lower--or ideally equal--than the superficial tissue temperature. The lesion size is influenced by many parameters such as delivered RF power, electrode length, electrode orientation, blood flow and tissue contact. This review describes the influence of these different parameters on lesion formation and provides recommendations for different catheter types on selectable parameters such as target temperatures, power limits and RF durations.

  5. Factors Influencing Lesion Formation During Radiofrequency Catheter Ablation

    PubMed Central

    Eick, Olaf J

    2003-01-01

    In radiofrequency (RF) ablation, the heating of cardiac tissue is mainly resistive. RF current heats cardiac tissue and in turn the catheter electrode is being heated. Consequently, the catheter tip temperature is always lower - or ideally equal - than the superficial tissue temperature. The lesion size is influenced by many parameters such as delivered RF power, electrode length, electrode orientation, blood flow and tissue contact. This review describes the influence of these different parameters on lesion formation and provides recommendations for different catheter types on selectable parameters such as target temperatures, power limits and RF durations. PMID:16943910

  6. [Thrombus visualisation during radiofrequency catheter ablation. A case report].

    PubMed

    Maciag, Aleksander; Szwed, Hanna; Pytkowski, Mariusz; Kraska, Alicja; Sterliński, Maciej

    2005-10-01

    We report two patients in whom thrombus formation during radiofrequency catheter ablation was detected by echocardiography. Resolution of thrombus after intravenous use of heparin was observed in both patients. Transesophageal and intracardiac echocardiography may be useful in management of this complication.

  7. Pulmonary vein stenosis after catheter ablation: electroporation versus radiofrequency.

    PubMed

    van Driel, Vincent J H M; Neven, Kars G E J; van Wessel, Harry; du Pré, Bastiaan C; Vink, Aryan; Doevendans, Pieter A F M; Wittkampf, Fred H M

    2014-08-01

    Radiofrequency ablation inside pulmonary vein (PV) ostia can cause PV stenosis. A novel alternative method of ablation is irreversible electroporation, but the long-term response of PVs to electroporation ablation is unknown. In ten 6-month-old pigs (60-75 kg), the response of PVs to circular electroporation and radiofrequency ablation was compared. Ten consecutive, nonarcing, electroporation applications of 200 J were delivered 5 to 10 mm inside 1 of the 2 main PVs, using a custom-deflectable, 18-mm circular decapolar catheter. Inside the other PV, circular radiofrequency ablation was performed using 30 W radiofrequency applications via an irrigated 4-mm ablation catheter. PV angiograms were made before ablation, immediately after ablation, and after 3-month survival. PV diameters and heart size were measured. With electroporation ablation, PV ostial diameter decreased 11±10% directly after ablation, but had increased 19±11% after 3 months. With radiofrequency ablation, PV ostial diameter decreased 23±15% directly after ablation and remained 7±17% smaller after 3 months compared with preablation diameter despite a 21±7% increase in heart size during aging from 6 to 9 months. In this porcine model, multiple circumferential 200-J electroporation applications inside the PV ostia do not affect PV diameter at 3-month follow-up. Radiofrequency ablation inside PV ostia causes considerable PV stenosis directly after ablation, which persists after 3 months. © 2014 American Heart Association, Inc.

  8. Irrigated Tip Catheters for Radiofrequency Ablation in Ventricular Tachycardia

    PubMed Central

    Grothoff, Matthias; Dinov, Borislav; Kosiuk, Jedrzej; Richter, Sergio; Sommer, Philipp; Breithardt, Ole A.; Bollmann, Andreas; Arya, Arash; Hindricks, Gerhard

    2015-01-01

    Radiofrequency (RF) ablation with irrigated tip catheters decreases the likelihood of thrombus and char formation and enables the creation of larger lesions. Due to the potential dramatic consequences, the prevention of thromboembolic events is of particular importance for left-sided procedures. Although acute success rates of ventricular tachycardia (VT) ablation are satisfactory, recurrence rate is high. Apart from the progress of the underlying disease, reconduction and the lack of effective transmural lesions play a major role for VT recurrences. This paper reviews principles of lesion formation with radiofrequency and the effect of tip irrigation as well as recent advances in new technology. Potential areas of further development of catheter technology might be the improvement of mapping by better substrate definition and resolution, the introduction of bipolar and multipolar ablation techniques into clinical routine, and the use of alternative sources of energy. PMID:25705659

  9. Anesthetic Management in Radiofrequency Catheter Ablation of Ventricular Tachycardia

    PubMed Central

    Naeini, Payam S.; Razavi, Mehdi; Collard, Charles D.; Tolpin, Daniel A.; Anton, James M.

    2016-01-01

    Radiofrequency catheter ablation is increasingly being used to treat patients who have ventricular tachycardia, and anesthesiologists frequently manage their perioperative care. This narrative review is intended to familiarize anesthesiologists with preprocedural, intraprocedural, and postprocedural implications of this ablation. Ventricular tachycardia typically arises from structural heart disease, most often from scar tissue after myocardial infarction. Many patients thus affected will benefit from radiofrequency catheter ablation in the electrophysiology laboratory to ablate the foci of arrhythmogenesis. The pathophysiology of ventricular tachycardia is complex, as are the technical aspects of mapping and ablating these arrhythmias. Patients often have substantial comorbidities and tenuous hemodynamic status, necessitating pharmacologic and mechanical cardiopulmonary support. General anesthesia and monitored anesthesia care, when used for sedation during ablation, can lead to drug interactions and side effects in the presence of ventricular tachycardia, so anesthesiologists should also be aware of potential perioperative complications. We discuss variables that can help anesthesiologists safely guide patients through the challenges of radiofrequency catheter ablation of ventricular tachycardia. PMID:28100967

  10. Atrial fibrillation ablation using a closed irrigation radiofrequency ablation catheter.

    PubMed

    Golden, Keith; Mounsey, John Paul; Chung, Eugene; Roomiani, Pahresah; Morse, Michael Andew; Patel, Ankit; Gehi, Anil

    2012-05-01

    Catheter ablation is an effective therapy for symptomatic, medically refractory atrial fibrillation (AF). Open-irrigated radiofrequency (RF) ablation catheters produce transmural lesions at the cost of increased fluid delivery. In vivo models suggest closed-irrigated RF catheters create equivalent lesions, but clinical outcomes are limited. A cohort of 195 sequential patients with symptomatic AF underwent stepwise AF ablation (AFA) using a closed-irrigation ablation catheter. Recurrence of AF was monitored and outcomes were evaluated using Kaplan-Meier survival analysis and Cox proportional hazards models. Mean age was 59.0 years, 74.9% were male, 56.4% of patients were paroxysmal and mean duration of AF was 5.4 years. Patients had multiple comorbidities including hypertension (76.4%), tobacco abuse (42.1%), diabetes (17.4%), and obesity (mean body mass index 30.8). The median follow-up was 55.8 weeks. Overall event-free survival was 73.6% with one ablation and 77.4% after reablation (reablation rate was 8.7%). Median time to recurrence was 26.9 weeks. AF was more likely to recur in patients being treated with antiarrhythmic therapy at the time of last follow-up (recurrence rate 30.3% with antiarrhythmic drugs, 13.2% without antiarrhythmic drugs; hazard ratio [HR] 2.2, 95% confidence interval [CI] 1.1-4.4, P = 0.024) and in those with a history of AF greater than 2 years duration (HR 2.7, 95% CI 1.1-6.9, P = 0.038). Our study represents the largest cohort of patients receiving AFA with closed-irrigation ablation catheters. We demonstrate comparable outcomes to those previously reported in studies of open-irrigation ablation catheters. Given the theoretical benefits of a closed-irrigation system, a large head-to-head comparison using this catheter is warranted. ©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.

  11. Cost analysis of radiofrequency catheter ablation for atrial fibrillation.

    PubMed

    Gorenek, Bulent; Kudaiberdieva, Gulmira

    2013-09-10

    Atrial fibrillation is the most common arrhythmia associated with increased mortality and morbidity. Its management requires high healthcare expenditures; 52%-70% of expenses for AF care are constituted by hospitalization costs. The current management strategies of pharmacological rhythm control and pharmacological or invasive rate control show no difference in impact on major outcomes in patients with AF. Radiofrequency catheter ablation (RFA) has been shown to reduce the risk of AF recurrence, improve quality of life and reduce hospitalization rate as compared to pharmacological rhythm control and rate control strategies. This review summarizes current knowledge on cost and cost-effectiveness analysis of RFA for patients with atrial fibrillation.

  12. Temperature-Guided Radiofrequency Catheter Ablation of Accessory Pathway

    PubMed Central

    Choi, Yun Shik; Nam, Gi Byoung; Kim, Hyo Soo; Sohn, Dae Won; Oh, Byung Hee; Lee, Myung Mook; Park, Young Bae; Seo, Jung Don; Lee, Young Woo

    1997-01-01

    Objectives This study was performed to evaluate the usefulness of temperature-guided radiofrequency catheter ablation for the elimination of accessory pathway conduction in patients with Wolff-Parkinson-White syndrome. Methods Temperature-guided radiofrequency catheter ablation was attempted in 138 patients with 144 accessory pathways (88 pathways along the left free wall, 5 in the anteroseptal region, 2 in the midseptal region, 19 in the posteroseptal region and 30 along the right free wall). The energy source was a HAT 200S which regulated the power automatically to the set temperature of 70°C. Radiofrequency current was delivered through a thermocatheter to the atrial or ventricular side of mitral or tricuspid annulus. Results Accessory pathway conduction was eliminated in 130 of 144 pathways (90.3%). The mean power outputs of the successful ablations at the atrial side of the annulus were higher than those at the ventricular side (34.0±8.9W versus 20.0±7.6W, p<0.01). but the maximum temperatures were lower at the atrial side of the annulus than those at the ventricular side (66.4±14.0°C versus 77.2±6.4°C, p<0.01). There were 3 non-fatal complications (2.1%), 2 patients with hemopericardium and 1 with femoral artery thrombus, during or after ablation procedures. Recurrences of AV re-entrant tachycardia or delta wave on the electrocardiogram occured in 4 patients (2.8%) who had successful second procedures. There were no late complications during a mean follow-up period of 41±25 months (range, 3 to 55). Conclusion We conclude that 1) temperature-guided radiofrequency catheter ablation can be performed reliably and safely in eliminating accessory pathway conduction in patients with WPW syndrome, and 2) temperature monitoring and adjustment of the power to the set temperature during ablation would be useful for the avoidance of impedance rises and coagulum formation. PMID:9439158

  13. Chronic incomplete atrioventricular block induced by radiofrequency catheter ablation

    SciTech Connect

    Huang, S.K.; Bharati, S.; Graham, A.R.; Gorman, G.; Lev, M. )

    1989-10-01

    To determine if catheter ablation of the atrioventricular (AV) junction with radiofrequency energy can induce chronic incomplete (first- and second-degree) AV block to avoid the need for a permanent pacemaker, 20 closed-chest dogs were studied. Group 1 (10 dogs) received radiofrequency energy (750 kHz) with a fixed power setting (5 or 10 W) while increasing the pulse duration from 10 to 50 seconds for each application. Group 2 (10 dogs) received energy with a fixed pulse duration (20 or 30 seconds) while increasing the power setting from 5 to 10 W or from 10 to 20 W during each energy delivery. Radiofrequency energy was delivered between a chest-patch electrode and the distal electrode of a regular 7F tripolar His bundle catheter. For each application, the energy delivery was interrupted when (1) the PR interval prolonged (greater than 50%) or (2) second-degree or complete AV block occurred and persisted up to 5 seconds. The ablation procedure ended when there was (1) persistent PR prolongation (greater than 50%) or persistent second-degree AV block (lasting greater than 30 minutes) after ablation, (2) occurrence of two consecutive transient (less than 1 minute) complete AV blocks after each energy delivery, or (3) complete AV block (lasting greater than 2 minutes) after ablation. Of seven dogs in group 1 and five dogs in group 2 in which incomplete AV block was achieved 1 hour after the procedure, six in group 1 and five in group 2 remained in incomplete AV block 2-3 months after ablation. One dog in group 1 progressed into complete AV block. Of the remaining three dogs in group 1 and five dogs in group 2 in which complete AV block was initially achieved 1 hour after ablation, two in group 1 and four in group 2 continued to have complete AV block, whereas one in each group had AV conduction returned to incomplete at 1-2 months of follow-up.

  14. Radiofrequency catheter ablation of ventricular tachycardia in a military parachuter.

    PubMed

    Ozturk, Cengiz; Cakmak, Tolga; Aparci, Mustafa; Metin, Suleyman; Yildirim, Ali Osman

    2013-10-01

    Premature ventricular contractions (PVCs) presenting as isolated complexes are insignificant, but if they present as salvos they are considered indicators of high risk for potentially fatal arrhythmias. We present the case of a 39-yr-old male military parachuter with PVCs and ventricular tachycardia that were incidentally detected on ECG and treated with radiofrequency catheter ablation (RFCA). He had no significant past medical history. Physical examination and biochemical tests were normal. Transthoracic echocardiography showed no structural heart disease. Due to frequent ventricular extrasystoles (VES) detected on his ECG, 24-h Holter monitoring was conducted and revealed VES, including 13,351 isolated PVCs, 1427 episodes of bigeminy, 397 of trigeminy, 30 couplets, and 4 salvo periods. After beta-blocker and calcium channel blocker treatment for 1 mo, his repeat 24-h Holter monitoring showed 18,414 isolated PVCs, 819 episodes of bigeminy, 181 of trigeminy, and 6 couplet VES, but no episodes of salvos. Electrophysiological studies (EPS) were performed and the baseline measurements were: basic cycle length: 890 ms; atrium His interval: 78 ms; and ventricular His interval: 54 ms. VES were found to orginate from the right ventricular outflow tract and were terminated by RFCA. Medical treatment was stopped. Repeat Holter showed no VES. The parachuter was qualified for full duties. As the patient is an aircrew member and further usage of antiarrhythmic agents will interfere with his flying status, instead of initiating a drug therapy again, we performed EPS and RFCA as an effective and dependable method in order to treat and to determine his fitness.

  15. In Vivo Evaluation and Proof of Radiofrequency Safety of a Novel Diagnostic MR-Electrophysiology Catheter

    PubMed Central

    Weiss, Steffen; Wirtz, Daniel; David, Bernd; Krueger, Sascha; Lips, Oliver; Caulfield, Dennis; Pedersen, Steen Fjord; Bostock, Julian; Razavi, Reza; Schaeffter, Tobias

    2013-01-01

    An MR-electrophysiology (EP) catheter is presented that provides full diagnostic EP functionality and a high level of radiofrequency safety achieved by custom-designed transmission lines. Highly resistive wires transmit intracardiac electrograms and currents for intracardiac pacing. A transformer cable transmits the localization signal of a tip coil. Specific absorption rate simulations and temperature measurements at 1.5 T demonstrate that a wire resistance > 3 kΩ/m limits dielectric heating to a physiologically irrelevant level. Additional wires do not increase tip specific absorption rate significantly, which is important because some clinical catheters require up to 20 electrodes. It is further demonstrated that radiofrequency-induced and pacing-induced resistive heating of the wires is negligible under clinical conditions. The MR-EP catheters provided uncompromised recording of electrograms and cardiac pacing in combination with a standard EP recorder in MR-guided in vivo EP studies, and the tip coil enabled fast and robust catheter localization. In vivo temperature measurements during such a study did not detect any device-related heating, which confirms the high level of safety of the catheter, whereas unacceptable heating was found with a standard EP catheter. The presented concept for the first time enables catheters with full diagnostic EP functionality and active tracking and at the same time a sufficient level of radiofrequency safety for MRI without specific absorption rate-related limitations. PMID:21337409

  16. In vivo evaluation and proof of radiofrequency safety of a novel diagnostic MR-electrophysiology catheter.

    PubMed

    Weiss, Steffen; Wirtz, Daniel; David, Bernd; Krueger, Sascha; Lips, Oliver; Caulfield, Dennis; Pedersen, Steen Fjord; Bostock, Julian; Razavi, Reza; Schaeffter, Tobias

    2011-03-01

    An MR-electrophysiology (EP) catheter is presented that provides full diagnostic EP functionality and a high level of radiofrequency safety achieved by custom-designed transmission lines. Highly resistive wires transmit intracardiac electrograms and currents for intracardiac pacing. A transformer cable transmits the localization signal of a tip coil. Specific absorption rate simulations and temperature measurements at 1.5 T demonstrate that a wire resistance > 3 kΩ/m limits dielectric heating to a physiologically irrelevant level. Additional wires do not increase tip specific absorption rate significantly, which is important because some clinical catheters require up to 20 electrodes. It is further demonstrated that radiofrequency-induced and pacing-induced resistive heating of the wires is negligible under clinical conditions. The MR-EP catheters provided uncompromised recording of electrograms and cardiac pacing in combination with a standard EP recorder in MR-guided in vivo EP studies, and the tip coil enabled fast and robust catheter localization. In vivo temperature measurements during such a study did not detect any device-related heating, which confirms the high level of safety of the catheter, whereas unacceptable heating was found with a standard EP catheter. The presented concept for the first time enables catheters with full diagnostic EP functionality and active tracking and at the same time a sufficient level of radiofrequency safety for MRI without specific absorption rate-related limitations.

  17. Radiofrequency catheter ablation of the atrioventricular junction from the left ventricle

    SciTech Connect

    Sousa, J.; el-Atassi, R.; Rosenheck, S.; Calkins, H.; Langberg, J.; Morady, F. )

    1991-08-01

    The purpose of this study was to describe a new technique for catheter ablation of the atrioventricular junction using radiofrequency energy delivered in the left ventricle. Catheter ablation of the atrioventricular (AV) junction using a catheter positioned across the tricuspid annulus was unsuccessful in eight patients with a mean {plus minus} SD age of 51 {plus minus} 19 years who had AV nodal reentry tachycardia (three patients), orthodromic tachycardia using a concealed midseptal accessory pathway, atrial tachycardia, atrial flutter (two patients), or atrial fibrillation. Before attempts at catheter ablation of the AV junction, each patient had been refractory to pharmacological therapy, and four had failed attempts at either catheter modification of the AV node using radiofrequency energy or surgical and catheter ablation of the accessory pathway. Conventional right-sided catheter ablation of the AV junction using radiofrequency energy in six patients and both radiofrequency energy and direct current shocks in two patients was ineffective. The mean amplitude of the His bundle potential recorded at the tricuspid annulus at the sites of unsuccessful AV junction ablation was 0.1 {plus minus} 0.08 mV, with a maximum His amplitude of 0.03-0.28 mV. A 7F deflectable-tip quadripolar electrode catheter with a 4-mm distal electrode was positioned against the upper left ventricular septum using a retrograde aortic approach from the femoral artery. Third-degree AV block was induced in each of the eight patients with 20-36 W applied for 15-30 seconds. The His bundle potential at the sites of successful AV junction ablation ranged from 0.06 to 0.99 mV, with a mean of 0.27 {plus minus} 0.32 mV. There was no rise in the creatine kinase-MB fraction and no complications occurred. An intrinsic escape rhythm of 30-60 beats/min was present in seven of the eight patients.

  18. Microembolism and catheter ablation I: a comparison of irrigated radiofrequency and multielectrode-phased radiofrequency catheter ablation of pulmonary vein ostia.

    PubMed

    Haines, David E; Stewart, Mark T; Dahlberg, Sarah; Barka, Noah D; Condie, Cathy; Fiedler, Gary R; Kirchhof, Nicole A; Halimi, Franck; Deneke, Thomas

    2013-02-01

    Cerebral diffusion-weighted MRI lesions have been observed after catheter ablation of atrial fibrillation. We hypothesized that conditions predisposing to microembolization could be identified using a porcine model of pulmonary vein ablation and an extracorporeal circulation loop. Ablations of the pulmonary veins were performed in 18 swine with echo monitoring. The femoral artery and vein were cannulated and an extracorporeal circulation loop with 2 ultrasonic bubble detectors and a 73-μm filter were placed in series. Microemboli and microbubbles were compared between ablation with an irrigated radiofrequency system (Biosense-Webster) and a phased radiofrequency multielectrode system (pulmonary vein ablation catheter [PVAC], Medtronic, Inc, Carlsbad, CA) in unipolar and 3 blended unipolar/bipolar modes. Animal pathology was examined. The size and number of microbubbles observed during ablation ranged from 30 to 180 μm and 0 to 3253 bubbles per ablation. Microbubble volumes with PVAC (29.1 nL) were greater than with irrigated radiofrequency (0.4 nL; P=0.045), and greatest with type II or III microbubbles on transesophageal echocardiography. Ablation with the PVAC showed fewest microbubbles in the unipolar mode (P=0.012 versus bipolar). The most occurred during bipolar energy delivery with overlap of proximal and distal electrodes (median microbubble volume, 1744 nL; interquartile range, 737-4082 nL; maximum, 19 516 nL). No cerebral MRI lesions were seen, but 2 animals had renal embolization. Left atrial ablation with irrigated radiofrequency and PVAC catheters in swine is associated with microbubble and microembolus production. Avoiding overlap of electrodes 1 and 10 on PVAC should reduce the microembolic burden associated with this procedure.

  19. The effect of radiofrequency catheter ablation on permanent pacemakers: an experimental study.

    PubMed

    Chin, M C; Rosenqvist, M; Lee, M A; Griffin, J C; Langberg, J J

    1990-01-01

    Radiofrequency current is being investigated as an alternative to direct current shock for transcatheter ablation of cardiac arrhythmias. Permanent pacemakers are known to be susceptible to high frequency electromagnetic interference. This study was performed to examine the effects of transcatheter radiofrequency ablation on permanent pacemakers in a worst-case scenario. Nineteen pulse generators representing 16 models from seven manufacturers were acutely implanted in 12 dogs to assess their function during and after ablation. Pulse generators were implanted subcutaneously in the neck and connected to a transvenous permanent pacing lead positioned in the right ventricular apex. A 6F quadripolar electrode catheter was positioned approximately 1 cm from the tip of the permanent pacing lead. Radiofrequency current from an electrosurgical unit was applied between the distal electrode of the catheter and a large diameter skin electrode placed below the left scapula. Three additional ablation sessions were performed with the catheter situated 4-5 cm from the permanent pacing lead. Each ablation consisted of 15 W of radiofrequency power, delivered for up to 30 seconds. Twelve pulse generators were falsely inhibited during radiofrequency ablation while programmed to the VVI or DDD mode, nine of which continued to be inhibited while programmed to the VOO or DOO mode. Five pulse generators paced at abnormal rates, including three examples of one pulse generator model that displayed pacemaker runaway. Runaway was observed during eight ablations, resulting in two episodes of ventricular fibrillation. Eleven pulse generators reverted to noise mode behavior during ablation. Only three pulse generators were unaffected during ablation. No reprogramming or pacing system malfunctions were observed after cessation of radiofrequency current application or during ablations greater than 4 cm from the permanent lead.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Initial impedance decrease as an indicator of good catheter contact: insights from radiofrequency ablation with force sensing catheters.

    PubMed

    Reichlin, Tobias; Knecht, Sven; Lane, Christopher; Kühne, Michael; Nof, Eyal; Chopra, Nagesh; Tadros, Thomas M; Reddy, Vivek Y; Schaer, Beat; John, Roy M; Osswald, Stefan; Stevenson, William G; Sticherling, Christian; Michaud, Gregory F

    2014-02-01

    Good catheter-tissue contact force (CF) is critical for transmural and durable lesion formation during radiofrequency (RF) ablation but is difficult to assess in clinical practice. Tissue heating during RF application results in an impedance decrease at the catheter tip. The purpose of this study was to correlate achieved CF and initial impedance decreases during atrial fibrillation (AF) ablation. We correlated achieved CF and initial impedance decreases in patients undergoing ablation for AF with two novel open-irrigated CF-sensing RF catheters (Biosense Webster SmartTouch, n = 647 RF applications; and Endosense TactiCath, n = 637 RF applications). We then compared those impedance decreases to 691 RF applications with a standard open-irrigated RF catheter (Biosense Webster ThermoCool). When RF applications with the CF-sensing catheters were analyzed according to an achieved average CF <5 g, 5-10 g, 10-20 g, and >20 g, the initial impedance decreases during ablation were larger with greater CF. Corresponding median values at 20 seconds were 5 Ω (interquartile range [IQR] 2-7), 8 Ω (4-11), 10 Ω (7-16), and 14 Ω (10-19) with the SmartTouch and n/a, 4 Ω (0-10), 8 Ω (5-12), and 13 Ω (8-18) with the TactiCath (P <.001 between categories for both catheters). When RF applications with the SmartTouch (CF-sensing catheter, median achieved CF 12 g) and ThermoCool (standard catheter) were compared, the initial impedance decrease was significantly greater in the CF-sensing group with median decreases of 10 Ω (6-14 Ω) vs 5 Ω (2-10 Ω) at 20 seconds (P <.001 between catheters). The initial impedance decrease during RF applications in AF ablations is larger when greater catheter contact is achieved. Monitoring of the initial impedance decrease is a widely available indicator of catheter contact and may help to improve formation of durable ablation lesions. © 2013 Heart Rhythm Society Published by Heart Rhythm Society All rights reserved.

  1. Endovascular radiofrequency ablation. Effect on the vein diameter using the ClosureFast(®) catheter.

    PubMed

    Bauzá Moreno, Hernán; Dotta, Mariana; Katsini, Roxana; Marquez Fosser, Carolina; Rochet, Sofía; Pared, Carlos; Martinez, Hugo

    2016-01-01

    Endovascular radiofrequency with first generation catheters was not successful due to its technical difficulty and restrictions in veins with diameters larger than 12mm. However, using the new catheter there is not enough scientific evidence to affirm that the diameter represents a technical limitation. The aim of this study was to evaluate and compare pre and post-operative venous trunks diameter, aiming at the reduction of size after 6 months with last generation catheters. Retrospective observational and descriptive study on a cohort of patients with insufficiency of the great saphenous vein, small saphenous vein and anterior accessory vein operated on with last generation radiofrequency catheters. The diameters were evaluated in the pre and post-operative period with ultrasound. Between 2007 and 2014 a total of 365 ablations were performed in veins with an average diameter of 9±3.1mm showing a reduction of it after 6 months with a mean value of 5.2±0.8mm (P<.0001). Total occlusion was also observed in 100% of cases and complications such as deep vein thrombosis in 0.5% and heat-induced thrombosis in 1.1%. A significant reduction in venous diameter after endovascular treatment with the new ClosureFast(®) catheters was checked, even in veins with diameters greater than 12mm. Copyright © 2016 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

  2. Radiofrequency catheter ablation versus balloon cryoablation of atrial fibrillation: markers of myocardial damage, inflammation, and thrombogenesis.

    PubMed

    Antolič, Bor; Pernat, Andrej; Cvijić, Marta; Žižek, David; Jan, Matevž; Šinkovec, Matjaž

    2016-07-01

    Evidence from animal and human studies suggests that cryoablation might be associated with a lesser inflammatory response and activation of coagulation compared with radiofrequency ablation. The study was aimed at comparing the effect of cryoballoon and radiofrequency catheter ablation of paroxysmal atrial fibrillation on markers of myocardial damage, inflammation, and activation of coagulation. Forty-one patients received either cryoballoon (n = 23) or radiofrequency (n = 18) ablation of atrial fibrillation. We measured troponin I, high-sensitivity CRP, and interleukin 6 at baseline from the cubital vein, and from the right and left atrium before and after ablation, and from the cubital vein the following day. Prothrombin fragments 1 + 2, soluble P‑selectin, and D‑dimer were measured before and after ablation from both atria. We observed higher troponin I release in the cryoballoon than in the radiofrequency group (7.01 mcg/l (interquartile range [IQR]: 5.30-9.09) vs 2.32 mcg/l (IQR: 1.45-2.98), p < 0.001). The levels of inflammatory markers (high-sensitivity CRP and interleukin 6) in the two groups were comparable, as were the levels of markers of coagulation activation. Procedure duration, fluoroscopy times, and mid-term success (23 months, IQR 7-32) of the two groups were also comparable. Cryoballoon ablation of atrial fibrillation causes more significant myocardial damage, that is, more extensive ablation lesions, compared with radiofrequency catheter ablation. However, no major differences between these two ablation techniques with regard to the inflammatory response and activation of the coagulation system were observed.

  3. Robust classification of contact orientation between tissue and an integrated spectroscopy and radiofrequency ablation catheter

    NASA Astrophysics Data System (ADS)

    Zaryab, Mohammad; Singh-Moon, Rajinder P.; Hendon, Christine P.

    2017-02-01

    Using light-based catheters for radiofrequency ablation (RFA) therapies grants the ability to accurately derive tissue properties such as lesion depth and overtreatment from spectroscopic information. However, this information is heavily reliant on contact quality with the treatment area and the orientation of the catheter. Thus to improve assessments of tissue properties, this work utilizes Bayesian modelling to classify whether the catheter is indeed in proper contact with the tissue. Initially in-laboratory experiments were conducted with ten fresh swine hearts submerged in blood. A total of 1555 unique near infrared spectra were collected from a spectrometer using a light-based catheter and manually tagged as "full perpendicular contact," "angled contact," and "no contact," between the catheter and heart tissue. Three features were prominent in all spectra for distinguishing purposes: area underneath the spectra, an intensity "valley" between 730 nm and 800 nm, along with the slope between 850 nm and 1150 nm. A classifier featuring bootstrapping, adaboost, and k-means techniques was thus created and achieved a 96.05% accuracy in classifying full contact, 98.33% accuracy in classifying angled contact, and 100% accuracy in classifying no contact.

  4. In vitro assessment of a combined radiofrequency ablation and cryo-anchoring catheter for treatment of mitral valve prolapse.

    PubMed

    Boronyak, Steven M; Merryman, W David

    2014-03-21

    Percutaneous approaches to mitral valve repair are an attractive alternative to surgical repair or replacement. Radiofrequency ablation has the potential to approximate surgical leaflet resection by using resistive heating to reduce leaflet size, and cryogenic temperatures on a percutaneous catheter can potentially be used to reversibly adhere to moving mitral valve leaflets for reliable application of radiofrequency energy. We tested a combined cryo-anchoring and radiofrequency ablation catheter using excised porcine mitral valves placed in a left heart flow loop capable of reproducing physiologic pressure and flow waveforms. Transmitral flow and pressure were monitored during the cryo-anchoring procedure and compared to baseline flow conditions, and the extent of radiofrequency energy delivery to the mitral valve was assessed post-treatment. Long term durability of radiofrequency ablation treatment was assessed using statically treated leaflets placed in a stretch bioreactor for four weeks. Transmitral flow and pressure waveforms were largely unaltered during cryo-anchoring. Parameter fitting to mechanical data from leaflets treated with radiofrequency ablation and cryo-anchoring revealed significant mechanical differences from untreated leaflets, demonstrating successful ablation of mitral valves in a hemodynamic environment. Picrosirius red staining showed clear differences in morphology and collagen birefringence between treated and untreated leaflets. The durability study indicated that statically treated leaflets did not significantly change size or mechanics over four weeks. A cryo-anchoring and radiofrequency ablation catheter can adhere to and ablate mitral valve leaflets in a physiologic hemodynamic environment, providing a possible percutaneous alternative to surgical leaflet resection of mitral valve tissue.

  5. [Successful radiofrequency catheter ablation of the symptomatic ventricular tachycardia in structurally normal heart. Case report].

    PubMed

    Maciag, Aleksander; Sterliński, Maciej; Pytkowski, Mariusz; Jankowska, Agnieszka; Szwed, Hanna

    2003-12-01

    Radiofrequency catheter ablation (RFA) in structurally normal heart ventricular arrhythmias has been found to be promising direction of develop. Authors presented the case of successful RFA of symptomatic ventricular tachycardia originating from right ventricle outflow tract (RVOT). Arrhythmogenic locus was localised basing on ECG pattern, analyze of endocardial potentials and pace mapping method. In two-year follow up she was free of symptoms and ventricular arrhythmia, no medication needed. RFA is an effective and safe therapy in ventricular tachycardia in structurally normal heart.

  6. Fiber-optic catheter-based polarization-sensitive OCT for radio-frequency ablation monitoring

    PubMed Central

    Fu, Xiaoyong; Wang, Zhao; Wang, Hui; Wang, Yves T; Jenkins, Michael W; Rollins, Andrew M

    2015-01-01

    An all-fiber optic catheter-based polarization-sensitive optical coherence tomography system is demonstrated. A novel multiplexing method was used to illuminate the sample, splitting the light from a 58.5kHz Fourier-domain mode-locked laser such that two different polarization states, alternated in time, are generated by two semiconductor optical amplifiers. A 2.3mm forward-view cone-scanning catheter probe was designed, fabricated, and used to acquire sample scattering intensity and phase retardation images. The system was first verified with a quarter-wave plate and then by obtaining intensity and phase retardation images of high-birefringence plastic, human skin in vivo, and untreated and thermally ablated porcine myocardium ex vivo. The system can potentially in vivo image of the cardiac wall to aid radio-frequency ablation therapy for cardiac arrhythmias. PMID:25166075

  7. [Infectious mitral endocarditis after radiofrequency catheter ablation of a left lateral accessory pathway].

    PubMed

    Benito Bartolomé, F; Sánchez Fernández-Bernal, C

    2001-08-01

    A 2-years-old child with Wolff-Parkinson-White syndrome associated with life-threatening symptoms underwent radiofrequency ablation of a left lateral accessory pathway. A deflectable 5F bipolar electrode catheter positioned above the atrioventricular groove by transeptal approach was used for ablation. The catheters were repeatedly used after ethylene oxide sterilisation. Although immediate post-ablation echocardiography demonstrated no complications, the patient was readmitted two days later with fever and a new mitral murmur. Penicillin-susceptible Staphylococcus aureus was isolated and intravenous antibiotics were administered. In the following weeks, the patient developed constrictive pericarditis requiring surgical treatment and acute hemiplegia caused by brain embolism arising from valvular vegetation. At 5 years of follow-up the patient presents residual hemiparesia and grade II/IV mitral insufficiency.

  8. Towards patient-specific modelling of lesion formation during radiofrequency catheter ablation for atrial fibrillation

    PubMed Central

    Soor, Navjeevan; Morgan, Ross; Varela, Marta; Aslanidi, Oleg V.

    2017-01-01

    Radiofrequency catheter ablation procedures are a first-line method of clinical treatment for atrial fibrillation. However, they suffer from suboptimal success rates and are also prone to potentially serious adverse effects. These limitations can be at least partially attributed to the inter- and intra- patient variations in atrial wall thickness, and could be mitigated by patient-specific approaches to the procedure. In this study, a modelling approach to optimising ablation procedures in subject-specific 3D atrial geometries was applied. The approach enabled the evaluation of optimal ablation times to create lesions for a given wall thickness measured from MRI. A nonliner relationship was revealed between the thickness and catheter contact time required for fully transmural lesions. Hence, our approach based on MRI reconstruction of the atrial wall combined with subject-specific modelling of ablation can provide useful information for improving clinical procedures.

  9. An efficient cardiac mapping strategy for radiofrequency catheter ablation with active learning.

    PubMed

    Feng, Yingjing; Guo, Ziyan; Dong, Ziyang; Zhou, Xiao-Yun; Kwok, Ka-Wai; Ernst, Sabine; Lee, Su-Lin

    2017-07-01

    A major challenge in radiofrequency catheter ablation procedures is the voltage and activation mapping of the endocardium, given a limited mapping time. By learning from expert interventional electrophysiologists (operators), while also making use of an active-learning framework, guidance on performing cardiac voltage mapping can be provided to novice operators or even directly to catheter robots. A learning from demonstration (LfD) framework, based upon previous cardiac mapping procedures performed by an expert operator, in conjunction with Gaussian process (GP) model-based active learning, was developed to efficiently perform voltage mapping over right ventricles (RV). The GP model was used to output the next best mapping point, while getting updated towards the underlying voltage data pattern as more mapping points are taken. A regularized particle filter was used to keep track of the kernel hyperparameter used by GP. The travel cost of the catheter tip was incorporated to produce time-efficient mapping sequences. The proposed strategy was validated on a simulated 2D grid mapping task, with leave-one-out experiments on 25 retrospective datasets, in an RV phantom using the Stereotaxis Niobe(®) remote magnetic navigation system, and on a tele-operated catheter robot. In comparison with an existing geometry-based method, regression error was reduced and was minimized at a faster rate over retrospective procedure data. A new method of catheter mapping guidance has been proposed based on LfD and active learning. The proposed method provides real-time guidance for the procedure, as well as a live evaluation of mapping sufficiency.

  10. Pacemakers implantation and radiofrequency catheter ablation procedures during medical missions in Morocco: an 8-year experience.

    PubMed

    Bun, Sok-Sithikun; Latcu, Decebal Gabriel; Errahmouni, Abdelkarim; Zarqane, Naïma; Yaïci, Khelil; Moustaghfir, Abdelhamid; Tazi-Mezalek, Amale; Saoudi, Nadir

    2016-07-01

    Radiofrequency catheter ablation (RFCA) for arrhythmias in the context of short-term medical missions (MM) in a developing country has not been reported so far. We describe here our experience with RFCA and pacemaker implantation in Morocco with a fully portable electrophysiological (EP) system under the auspice of the Monaco-Morocco Cardiology Association. Since November 2007, two to three MM (mean duration 4 days including transportation) per year were conducted (including two physicians and one nurse from Monaco) and were alternately located in Marrakech, Fes, Agadir, Casablanca, Rabat, Essaouira, and Oujda. All patients' files were sent by local teams and/or referring Moroccan cardiologists before MM. Each case was discussed with the Monaco EP team before the MM. Pacemakers and leads were donated by companies (Sorin Group, Medtronic, Saint-Jude Medical). The EP system (EP Tracer, CardioTek) as well as diagnostic/ablation catheters were brought for RFCA procedures. After the procedures, follow-up was performed by local teams. Procedures took place in gynaecological or orthopaedic operating room, or, when available, in the interventional cardiology cathlab. Thirty-one RFCA were performed during 11 MM (atrioventricular node re-entrant tachycardia = 12; atrioventricular re-entrant tachycardia/Mahaïm fibre = 15; typical atrial flutter = 3; ventricular ectopy = 1). Acute success was 93.5% for RFCA. Two major RFCA-related complications occurred (air embolism and complete atrioventricular block). No complication was related to pacemaker implantations (n = 44; mean 4 pacemakers per mission). Radiofrequency catheter ablation for arrhythmias in developing countries is technically challenging but feasible, despite technical and cultural difficulties. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

  11. Simplified method for esophagus protection during radiofrequency catheter ablation of atrial fibrillation--prospective study of 704 cases.

    PubMed

    Mateos, José Carlos Pachón; Mateos, Enrique I Pachón; Peña, Tomas G Santillana; Lobo, Tasso Julio; Mateos, Juán Carlos Pachón; Vargas, Remy Nelson A; Pachón, Carlos Thiene C; Acosta, Juán Carlos Zerpa

    2015-01-01

    Although rare, the atrioesophageal fistula is one of the most feared complications in radiofrequency catheter ablation of atrial fibrillation due to the high risk of mortality. This is a prospective controlled study, performed during regular radiofrequency catheter ablation of atrial fibrillation, to test whether esophageal displacement by handling the transesophageal echocardiography transducer could be used for esophageal protection. Seven hundred and four patients (158 F/546M [22.4%/77.6%]; 52.8 ± 14 [17-84] years old), with mean EF of 0.66 ± 0.8 and drug-refractory atrial fibrillation were submitted to hybrid radiofrequency catheter ablation (conventional pulmonary vein isolation plus AF-Nests and background tachycardia ablation) with displacement of the esophagus as far as possible from the radiofrequency target by transesophageal echocardiography transducer handling. The esophageal luminal temperature was monitored without and with displacement in 25 patients. The mean esophageal displacement was 4 to 9.1cm (5.9 ± 0.8 cm). In 680 of the 704 patients (96.6%), it was enough to allow complete and safe radiofrequency delivery (30W/40ºC/irrigated catheter or 50W/60ºC/8 mm catheter) without esophagus overlapping. The mean esophageal luminal temperature changes with versus without esophageal displacement were 0.11 ± 0.13ºC versus 1.1 ± 0.4ºC respectively, P<0.01. The radiofrequency had to be halted in 68% of the patients without esophageal displacement because of esophageal luminal temperature increase. There was no incidence of atrioesophageal fistula suspected or confirmed. Only two superficial bleeding caused by transesophageal echocardiography transducer insertion were observed. Mechanical esophageal displacement by transesophageal echocardiography transducer during radiofrequency catheter ablation was able to prevent a rise in esophageal luminal temperature, helping to avoid esophageal thermal lesion. In most cases, the esophageal displacement was

  12. Simplified method for esophagus protection during radiofrequency catheter ablation of atrial fibrillation - prospective study of 704 cases

    PubMed Central

    Mateos, José Carlos Pachón; Mateos, Enrique I Pachón; Peña, Tomas G Santillana; Lobo, Tasso Julio; Mateos, Juán Carlos Pachón; Vargas, Remy Nelson A; Pachón, Carlos Thiene C; Acosta, Juán Carlos Zerpa

    2015-01-01

    Introduction Although rare, the atrioesophageal fistula is one of the most feared complications in radiofrequency catheter ablation of atrial fibrillation due to the high risk of mortality. Objective This is a prospective controlled study, performed during regular radiofrequency catheter ablation of atrial fibrillation, to test whether esophageal displacement by handling the transesophageal echocardiography transducer could be used for esophageal protection. Methods Seven hundred and four patients (158 F/546M [22.4%/77.6%]; 52.8±14 [17-84] years old), with mean EF of 0.66±0.8 and drug-refractory atrial fibrillation were submitted to hybrid radiofrequency catheter ablation (conventional pulmonary vein isolation plus AF-Nests and background tachycardia ablation) with displacement of the esophagus as far as possible from the radiofrequency target by transesophageal echocardiography transducer handling. The esophageal luminal temperature was monitored without and with displacement in 25 patients. Results The mean esophageal displacement was 4 to 9.1cm (5.9±0.8 cm). In 680 of the 704 patients (96.6%), it was enough to allow complete and safe radiofrequency delivery (30W/40ºC/irrigated catheter or 50W/60ºC/8 mm catheter) without esophagus overlapping. The mean esophageal luminal temperature changes with versus without esophageal displacement were 0.11±0.13ºC versus 1.1±0.4ºC respectively, P<0.01. The radiofrequency had to be halted in 68% of the patients without esophageal displacement because of esophageal luminal temperature increase. There was no incidence of atrioesophageal fistula suspected or confirmed. Only two superficial bleeding caused by transesophageal echocardiography transducer insertion were observed. Conclusion Mechanical esophageal displacement by transesophageal echocardiography transducer during radiofrequency catheter ablation was able to prevent a rise in esophageal luminal temperature, helping to avoid esophageal thermal lesion. In most

  13. Irrigated-tip catheters for radiofrequency ablation of right-sided accessory pathways in adolescents.

    PubMed

    Telishevska, Marta; Faelchle, Johannes; Buiatti, Allessandra; Busch, Sonia; Reents, Tilko; Bourier, Felix; Semmler, Verena; Kaess, Bernhardt; Horndasch, Michaela; Kornmayer, Marielouise; Kottmaier, Marc; Deisenhofer, Isabel; Hessling, Gabriele

    2017-09-01

    Catheter ablation of right sided accessory pathways (AP) has lower success and higher recurrence rates compared to left-sided substrates. Irrigated-tip catheter (ITC) ablation might offer an advantage in this setting but data about its use in patients below 18 years is scarce. Aim of this study was to compare an ITC approach to conventional catheter ablation. A retrospective analysis of all patients < 18 years undergoing radiofrequency ablation (RFA) for right-sided APs from 2004 to 2014 at our institution was performed. Patients either underwent an ITC approach in combination with 3-D mapping (Group 1; n = 53) or a conventional non-ITC approach (Group 2; n = 52). Study endpoints were acute procedural success, safety and recurrence rate. A total of 105 mostly adolescent patients (56.2% male; median age 14 years) with 107 right sided- APs were included. The prevailing anatomic AP locations were right posteroseptal (44.9%), right anterior/anterolateral (24.3%) and right lateral (13.1%). Acute success (94.3% vs 94.2%) did not differ between the groups. One major complication (pericardial effusion) occurred in the non-ITC group. Overall, freedom from AP recurrence was 94% at 4 year in the ITC group, and 81% at 4 year in the non-ITC group (p = 0.04). The use of irrigated tip catheters in combination with 3-D mapping system for ablation of right- sided APs in adolescents has a high acute success rate, is safe and associated with a significantly reduced recurrence rate compared to a non-ITC/conventional approach. It might be considered as alternative approach in this age group. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  14. Teflon-buttressed sutures plus pericardium patch repair left ventricular rupture caused by radiofrequency catheter ablation

    PubMed Central

    Cao, Hao; Zhang, Qi; He, Yanzhong; Feng, Xiaodong; Liu, Zhongmin

    2016-01-01

    Abstract Background: Cardiac rupture often occurs after myocardial infarction or chest trauma with a high mortality rate. However, left ventricular rupture caused by radiofrequency catheter ablation (RFCA) is extremely rare. Methods: We describe a case of a 61-year-old male who survived from left ventricular rupture caused by a RFCA procedure for frequent ventricular premature contractions. Surgical exploration with cardiopulmonary bypass (CPB) was performed when the signs of cardiac tamponade developed 7 hours after the ablation surgery. Results: Teflon-buttressed sutures of the tear in the left ventricular posterolateral wall and pericardium patch applied to the contusion region on the wall repaired the rupture safely and effectively. Conclusion: Timely surgical intervention under CPB facilitated the survival of the patient. Teflon-buttressed sutures plus pericardium patch achieved the successful repair of the rupture. PMID:27661047

  15. Inappropriate Sinus Tachycardia Diagnosed and Treated as Depression Successfully Treated by Radiofrequency Catheter Ablation.

    PubMed

    Masumoto, Akihiro; Takemoto, Masao; Mito, Takahiro; Tanaka, Atsushi; Kawano, Yuki; Kumeda, Hiroshi; Kang, Honsa; Matsuo, Atsutoshi; Hida, Satoru; Okazaki, Teiji; Tayama, Kei-Ichiro; Yoshitake, Kiyonobu; Kosuga, Kenichi

    2017-01-01

    We experienced a man in his 20s with inappropriate sinus tachycardia (IST) initially diagnosed and treated as depression who was steadily treated with radiofrequency catheter ablation (RFCA) using an EnSite™ system. The patient has remained well without any symptoms or medications, including antidepressants, for two years since the RFCA. To avoid missing IST and treating it as an emotional problem and/or mental illness such as depression, physicians - including cardiologists - should be aware of these conditions when examining patients with multiple and incapacitating complaints including palpitations and general fatigue and/or tachycardia, especially characterized by an elevated resting heart rate or a disproportionate increase in the heart rate with minimal exertion.

  16. Novel use of epidural catheter: Air injection for neuroprotection during radiofrequency ablation of spinal osteoid osteoma

    PubMed Central

    Doctor, JR; Solanki, SL; Patil, VP; Divatia, JV

    2016-01-01

    Osteoid osteoma (OO) is a benign bone tumor, with a male-female ratio of approximately 2:1 and mainly affecting long bones. Ten percent of the lesions occur in the spine, mostly within the posterior elements. Treatment options for OO include surgical excision and percutaneous imaging-guided radiofrequency ablation (RFA). Lesions within the spine have an inherent risk of thermal damage to the vital structure because of proximity to the neural elements. We report a novel use of the epidural catheter for air injection for the neuroprotection of nerves close to the OO of the spine. A 12-year-old and 30 kg male child with an OO of the L3 vertebra was taken up for RFA. His preoperative examinations were within normal limits. The OO was very close to the L3 nerve root. Under general anesthesia, lumbar epidural catheter was placed in the L3-L4 space under imaging guidance. Ten ml of aliquots of air was injected under imaging guidance to avoid injury to the neural structures due to RFA. The air created a gap between neural elements and the tumor and served as an insulating material thereby protecting the neural elements from damage due to the RFA. Postoperatively, the patient did not develop any neurological deficit. PMID:27375396

  17. The biophysics of radiofrequency catheter ablation in the heart: the importance of temperature monitoring.

    PubMed

    Haines, D E

    1993-03-01

    Radiofrequency (RF) catheter ablation is a technique whereby high frequency alternating electrical current with frequencies of 350 kHz to 1 MHz is delivered through electrode catheters to myocardial tissue creating a thermal lesion. The mechanism by which RF current heats tissue is resistive (or ohmic) heating of a narrow rim (< 1 mm) of tissue that is in direct contact with the electrode. Deeper tissue planes are then heated by conduction from the small region of volume heating. Heat is dissipated from the region by further heat conduction into normothermic tissue, and by heat convection via the circulating blood pool and larger coronary vessels. The lesion size is proportional to the temperature at the electrode-tissue interface (which is also a function of power level if electrical factors remain constant), and to the size of the electrode. At temperatures above 100 degrees C, boiling occurs at the electrode-tissue contact point resulting in a rapid rise in electrical impedance. Therefore, a theoretical maximum lesion size exists for any given electrode geometry. Other factors that are important for RF lesion formation include electrode-tissue contact pressure and duration of RF delivery. Temperature rises monoexponentially, and duration of energy delivery should be at least 35 to 45 seconds to approach steady state.

  18. Radiation exposure to operator and patients during cardiac electrophysiology study, radiofrequency catheter ablation and cardiac device implantation procedures

    NASA Astrophysics Data System (ADS)

    Lee, C. H.; Cho, J. H.; Park, S. J.; Kim, J. S.; On, Y. K.; Huh, J.

    2015-10-01

    The purpose of this study was to measure the radiation exposure to operator and patient during cardiac electrophysiology study, radiofrequency catheter ablation and cardiac device implantation procedures and to calculate the allowable number of cases per year. We carried out 9 electrophysiology studies, 40 radiofrequency catheter ablation and 11 cardiac device implantation procedures. To measure occupational radiation dose and dose-area product (DAP), 13 photoluminescence glass dosimeters were placed at eyes (inside and outside lead glass), thyroids (inside and outside thyroid collar), chest (inside and outside lead apron), wrists, genital of the operator (inside lead apron), and 6 of photoluminescence glass dosimeters were placed at eyes, thyroids, chest and genital of the patient. Exposure time and DAP values were 11.7 ± 11.8 min and 23.2 ± 26.2 Gy cm2 for electrophysiology study; 36.5 ± 42.1 min and 822.4 ± 125.5 Gy cm2 for radiofrequency catheter ablation; 16.2 ± 9.3 min and 27.8 ± 16.5 Gy cm2 for cardiac device implantation procedure, prospectively. 4591 electrophysiology studies can be conducted within the occupational exposure limit for the eyes (150 mSv), and 658-electrophysiology studies with radiofrequency catheter ablation can be carried out within the occupational exposure limit for the hands (500 mSv). 1654 cardiac device implantation procedure can be conducted within the occupational exposure limit for the eyes (150 mSv). The amounts of the operator and patient's radiation exposure were comparatively small. So, electrophysiology study, radio frequency catheter ablation and cardiac device implantation procedures are safe when performed with modern equipment and optimized protective radiation protect equipment.

  19. Intracardiac rhabdomyomas producing symptoms in infancy: the role of radiofrequency catheter ablation

    PubMed Central

    Emmel, M.; Brockmeier, K.; Sreeram, N.

    2006-01-01

    Background Cardiac rhabdomyomas, although benign, may produce symptoms related to arrhythmia or mechanical obstruction. Surgical excision is the therapy of choice for symptomatic rhabdomyomas in infancy. Patients and Methods Two infants with intracardiac rhabdomyomas producing symptoms underwent radiofrequency catheter ablation of the tumour. In patient 1 the diagnosis of multiple rhabdomyomas associated with recurrent supraventricular tachyarrhythmias and foetal hydrops was made in utero. After birth, several antiarrhythmic agents were administered, without successful suppression of the tachyarrhythmia. At seven months of age, the infant had one large residual tumour on the left atrial aspect of the anterior mitral valve leaflet with associated pre-excitation and re-entrant supraventricular tachyarrhythmia suggestive of a left-sided pathway. Catheter ablation of the accessory pathway was performed via a retrograde femoral arterial approach, targeting the earliest site of ventricular activation. Patient 2 presented as a neonate with multiple rhabdomyomas, one of which, measuring 15 mm × 15 mm, was producing severe mitral valve inflow obstruction resulting in symptoms of heart failure due to a large left-to-right shunt at atrial level and persistent pulmonary hypertension. Via the femoral vein, a 5F ablation catheter was advanced across the atrial septum, and the tumour directly ablated. Results Echocardiography performed 24 hours later demonstrated alteration in tumour morphology, with the development of a large central echolucent area, followed by progressive tumour shrinkage in both infants. Patient 1 was discharged at 24 hours, and patient 2 at seven days post-ablation, without symptoms. Follow-up at four weeks confirmed further tumour shrinkage. Conclusion Transcatheter tumour ablation may be beneficial in selected infants and children. ImagesFigure 2AFigure 2BFigure 2CFigure 3AFigure 3BFigure 3C PMID:25696636

  20. The results of electrophysiological study and radio-frequency catheter ablation in pediatric patients with tachyarrhythmia.

    PubMed

    Celiker, Alpay; Kafali, Gülden; Karagöz, Tevfik; Ceviz, Naci; Ozer, Sema

    2003-01-01

    A total of 135 consecutive pediatric patients (pts) with tachyarrhythmia ranging from two to 21 years of age (median age 11 years) underwent electrophysiological study (EPS) between January 1994 and July 2001. Tachycardia could not be induced in 38 of 135 pts (28%) and studies in these patients were accepted as the normal EPS. Supraventricular tachyarrhythmia mechanisms were atrioventricular (AV) accessory pathways in 47 patients (manifest accessory pathways in 23 patients, concealed accessory pathways in 17 patients, permanent junctional reciprocating tachycardia in 7 patients), re-entry without accessory pathway in 26 patients (AV nodal reentry tachycardia in 20 patients, atrial flutter in 5 patients, sinus node re-entry tachycardia in 1 patient) and atrial ectopic tachycardia in eight patients. The diagnosis of ventricular tachycardia (VT) was made in 16 patients. Seventy-three of the 97 patients with the diagnosis of tachyarrhythmia as a result of EPS underwent radiofrequency (RF) catheter ablation. The indications, early results, complications, safety and efficacy of RF catheter ablation were reviewed in these patients. Among the 73 patients who underwent RF ablation (85 procedures), the overall final success rate for all the diagnoses was 82% (60 of 73 patients). The median follow-up period for all patients was 16 months (range 2 to 60 months). Total recurrence rate in 73 patients was 4% (3 patients). Re-ablation was performed in only one of them and was successful. Procedure-related complications occurred in eight patients (11%): transient third-degree AV block in one patient, transient second-degree AV block in one patient, atrial flutter in two patients (1 needed direct current cardioversion), and atrial fibrillation in three patients (2 needed defibrillation and transient pacemaker implantation). In one patient with permanent third-degree AV block a transvenous pacemaker implantation was required. These midterm results suggest that RF catheter ablation

  1. Ablation with an internally irrigated radiofrequency catheter: learning how to avoid steam pops.

    PubMed

    Cooper, Joshua M; Sapp, John L; Tedrow, Usha; Pellegrini, Christine P; Robinson, David; Epstein, Laurence M; Stevenson, William G

    2004-09-01

    The aim of this study was to assess the feasibility of using electrode temperature, impedance, and power to predict and thereby potentially prevent steam pops during cooled radiofrequency (RF) ablation. When myocardial temperature reaches 100 degrees C during RF catheter ablation, steam explosions are seen. Saline-cooled RF ablation reduces temperatures at the electrode-tissue interface, but excessive intramyocardial heating still may occur. In anesthetized swine, 26 cooled RF applications were made in the right and left atria while observing with intracardiac echocardiography (ICE). Power delivery was increased gradually until a steam explosion was seen or a maximum output of 50 W was reached. ICE identified steam explosions in 21 RF applications. Steam explosions were associated with a large impedance increase, >25 Omega in only three cases, whereas small increases <10 Omega (mean 5.3 +/- 2.6 Omega) occurred in 18 cases. Mean electrode temperature at the time of steam explosion was 43.6 degrees C +/- 5.3; 18 of 21 explosions occurred when temperature reached >/=40 degrees C. Mean power and impedance drop were similar for applications with and without steam explosions. Five steam explosions were associated with a sudden drop in electrode temperature. Steam explosions are common when cooled electrode temperature exceeds 40 degrees C and are not predictable from power or impedance drop. Small impedance rises and sudden drops in measured electrode temperature indicate possible steam formation. Maintaining cooled electrode temperature <40 degrees C during RF likely will reduce the risk of steam explosions.

  2. Delayed efficacy of radiofrequency catheter ablation on ventricular arrhythmias originating from the left ventricular anterobasal wall.

    PubMed

    Ding, Ligang; Hou, Bingbo; Wu, Lingmin; Qiao, Yu; Sun, Wei; Guo, Jinrui; Zheng, Lihui; Chen, Gang; Zhang, Linfeng; Zhang, Shu; Yao, Yan

    2017-03-01

    Ventricular arrhythmias (VAs) originating from the left ventricular anterobasal wall (LV-ABW) may represent a therapeutic challenge. The purpose of this study was to investigate the delayed efficacy of radiofrequency catheter (RFCA) ablation without an epicardial approach on VAs originating from the LV-ABW. Eighty patients (mean age 46.9 ± 14.9 years; 47 male) with VAs originating from the LV-ABW were enrolled. After systematic mapping of the right ventricular outflow tract, aortic root, adjacent LV endocardium, and coronary venous system, 3-4 ablation attempts were made at the earliest activation sites and/or best pace-mapping sites. Delayed efficacy was evaluated in patients with acute failure. During mean follow-up of 23.8 ± 21.9 months (range 3-72 months), complete elimination of all VAs was achieved in 47 patients (59%) and partial success in 19 (24%), for an overall success rate of 83%. In 25 of 37 patients (68%) with acute failure, VAs were eliminated or significantly reduced (>80% VA burden) by the delayed effect of RFCA during follow-up. Logistic regression analysis revealed that response time to ablation was a predictor of occurrence of delayed efficacy. No complications occurred during follow-up. Instead of extensive ablation, waiting for delayed efficacy of RFCA may be a reasonable choice for patients with VAs arising from the LV-ABW. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  3. Radiofrequency catheter ablation of intractable ventricular tachycardia in an infant following arterial switch operation.

    PubMed

    Costello, John P; He, Dingchao; Greene, Elizabeth A; Berul, Charles I; Moak, Jeffrey P; Nath, Dilip S

    2014-01-01

    A full-term male neonate presented with cyanosis upon delivery and was subsequently diagnosed with d-transposition of the great arteries, ventricular septal defect, and restrictive atrial septal defect. Following initiation of intravenous prostaglandins and balloon atrial septostomy, an arterial switch operation was performed on day 3 of life. The postoperative course was complicated by intractable ventricular tachycardia that was refractory to lidocaine, amiodarone, esmolol, fosphenytoin, and mexiletine drug therapy. Ventricular tachycardia was suppressed with overdrive atrial pacing but recurred upon discontinuation. Seven weeks postoperatively, radiofrequency catheter ablation was performed due to hemodynamically compromising persistent ventricular tachycardia refractory to medical therapy. The ventricular tachycardia was localized to the inferior-lateral right ventricular outlet septum. The procedure was successful without complications or recurrence. Antiarrhythmics were discontinued after the ablation procedure. Seven days after the ablation, a different, slower fascicular rhythm was noted to compete with the infant's sinus rhythm. This was consistent with the preablation amiodarone having reached subtherapeutic levels given its very long half-life. The patient was restarted on oral beta blockers and amiodarone. The patient was subsequently discharged home in predominantly sinus rhythm with intermittent fascicular rhythm.

  4. Tachycardiomyopathy Induced by Ventricular Premature Complexes: Complete Recovery after Radiofrequency Catheter Ablation

    PubMed Central

    Rhee, Kyoung-Hoon; Jung, Ju-Young; Kim, Hyun-Sook; Chae, Jei-Keon; Kim, Won-Ho; Ko, Jae-Ki

    2006-01-01

    Ventricular premature complexes (VPCs) are known to be one of the most benign cardiac arrhythmias when they occur in structurally normal hearts. We experienced a 32-year old man who presented with dyspnea, palpitations and very frequent VPCs (31% of the total heart beats). Echocardiography revealed a dilated left ventricle (LV 66 mm at end-diastole and 57 mm at end-systole) and a decreased ejection fraction (34%). Very frequent VPCs had been detected 10 years previously and he underwent a failed radiofrequency catheter ablation (RFCA) procedure at that time. The patient had been treated with heart failure medications including betablockers, ACE inhibitors and spironolactone for the two most recent years. Six months after we eliminated these VPCs with a second RFCA procedure, the heart returned to normal function and size. Long standing and very frequent VPCs could be the cause of left ventricular dysfunction in a subset of patients who suffer with dilated cardiomyopathy, and RFCA should be the choice of therapy for these patients. PMID:17017676

  5. Cryoablation versus radiofrequency ablation for treatment of atrioventricular nodal reentrant tachycardia: cryoablation with 6-mm-tip catheters is still less effective than radiofrequency ablation.

    PubMed

    Opel, Aaisha; Murray, Sam; Kamath, Nikhil; Dhinoja, Mehul; Abrams, Dominic; Sporton, Simon; Schilling, Richard; Earley, Mark

    2010-03-01

    The treatment of choice for atrioventricular nodal reentrant tachycardia (AVNRT) is catheter ablation of the atrioventricular nodal slow pathway. The purpose of this study was to ascertain whether cryoablation (Cryo) with 6-mm-tip catheters is as effective as radiofrequency ablation (RF). Patients who had catheter ablation for AVNRT between 2005 and 2008 were identified. The main outcome measure was overall success without the use of an alternative energy source and no recurrence. Two hundred eighty-eight procedures in 272 patients were identified; 184 were female (68%), and the mean age was 53 +/- 14 (17-88) years. There were 123 Cryo and 149 RF procedures. Cryo had a lower overall success rate (83% vs. 93%; P = .02). Mean procedure times were similar in both groups (90 minutes; P = .5). Fluoroscopy time was longer with Cryo: 16 (7-48) versus 14 (5-50) minutes (P = .04). Only one case of atrioventricular block was observed in the RF group (0.7%). Cryo was more expensive than RF ( pounds sterling 3141 vs. pounds sterling 2153). Even when delivering multiple lesions with 6-mm-tip catheters, Cryo is less effective than RF. RF is recommended as a first-line treatment, although the only major complication occurred in the RF group. Copyright 2010 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  6. Safety and feasibility of transcatheter renal sympathetic denervation using different types of catheter and various radiofrequency settings.

    PubMed

    Andrea, Bruno Rustum; Atié, Jacob; Desh, Steffen; Lurz, Phillip; Hindricks, Gerhard

    2016-06-01

    To evaluate in vivo the feasibility and safety of renal sympathetic denervation (RSD) with different catheters and various radiofrequency protocols. Twenty-two pigs were included. First 2 pigs were enrolled in a feasibility protocol using one catheter and power from 5 W to 20 W. The next 10 pigs underwent RSD with three different catheters and four different RF-power settings of 5 W, 8 W, 10 W and 12 W in one minute per lesion (Protocol 1). The following 10 (Pigs 13 to 22) underwent RSD with five types of catheters (including the Symplicity® catheter), powers of 8 W and 10 W and two minutes RF-application (Protocol 2). Angiographic data were obtained at baseline, during and after RSD. At last, renal arteries were excised and analyzed macroscopically. The first pig developed severe renal stenoses with lesions of 15 to 20 W correlated with macroscopic alterations. The second feasibility pig did not develop renal stenosis with 5 and 8 W. In Protocol 1 from 60 RF-lesions, we observed 7 stenoses (≥ 30%). Three were severe (one of 80% with 10 W and two of 80% with 12 W). In Protocol 2 from 57 lesions we observed only 1 stenosis of 50% with 8 W with Symplicity® catheter. Severe stenosis was not observed. In this study, renal sympathetic denervation showed safety using five types of catheters when applying RF-energy less than 10 W, within main stems of arteries larger than 3.0 mm diameter and a distance between lesions of at least 1 time catheter tip length.

  7. Radiofrequency Ablation with an Enhanced-Irrigation Flexible-Tip Catheter versus a Standard-Irrigation Rigid-Tip Catheter.

    PubMed

    Hussein, Ayman A; Oberti, Carlos; Wazni, Oussama M; Hegrenes, Jami A; Sral, John A; Lopez, John; Kowalewski, William; Kattar, Jacqueline; Kanj, Mohamed; Lindsay, Bruce; Saliba, Walid

    2015-10-01

    The flexible-tip irrigated ablation catheter Cool Flex™ (St. Jude Medical, St. Paul, MN, USA) was introduced to enhance cooling of the catheter-tissue interface and to conform to endocardial surface with better contact. Little is known about the performance of such catheter design compared to the widely used rigid-tip catheters. In a thigh muscle preparation, ablation using the flexible-tip and rigid-tip catheters was performed in seven pigs across a range of ablation settings and catheter orientation. Postprocedure, the thigh muscle was stained with 2,3,5-triphenyltetrazolium-chloride injected into the femoral artery. The muscle was excised, fixed with formalin, and examined grossly. A total of 196 lesions (95 flexible tip, 101 rigid tip) were evaluated. The flexible-tip catheter was associated with enhanced cooling of catheter-tissue interface (31.1 ± 3.3°C vs 36.3 ± 3.7°C, P = 0.0001) in both perpendicular and nonperpendicular catheter orientations. This allowed more energy delivery (37.3 ± 8.9 W vs 33.7 ± 8.1 W, P = 0.004) to targeted tissue and resulted in larger lesions (median 194.7 [interquartile range: 113.1-333.8] mm(3) vs 170.9 [88.7-261.6] mm(3) , P = 0.03) than the rigid-tip catheter with larger maximum diameter (11.1 ± 2.6 mm vs 10.3 ± 2.1 mm, P = 0.03) and larger diameter at tissue surface (10.3 ± 2.4 mm vs 9.6 ± 1.7 mm, P = 0.01). Catheter orientation during ablation affected the efficiency of rigid-tip but not the flexible-tip catheter. The use of the flexible-tip catheter was associated with significantly less char formation on tissue (none vs 5.1% with rigid tip, P = 0.009). The Cool Flex™ catheter performed better than a rigid-tip catheter with enhanced cooling, larger ablation lesions, and no charring of targeted tissue. © 2015 Wiley Periodicals, Inc.

  8. Radiofrequency catheter ablation: different cooled and noncooled electrode systems induce specific lesion geometries and adverse effects profiles.

    PubMed

    Dorwarth, Uwe; Fiek, Michael; Remp, Thomas; Reithmann, Cristopher; Dugas, Martin; Steinbeck, Gerhard; Hoffmann, Ellen

    2003-07-01

    The success and safety of standard catheter radiofrequency ablation may be limited for ablation of atrial fibrillation and ventricular tachycardia. The aim of this study was to characterize and compare different cooled and noncooled catheter systems in terms of their specific lesion geometry, incidence of impedance rise, and crater and coagulum formation to facilitate appropriate catheter selection for special indications. The study investigated myocardial lesion generation of three cooled catheter systems (7 Fr, 4-mm tip): two saline irrigation catheters with a showerhead-type electrode tip (sprinkler) and a porous metal tip and an internally cooled catheter. Noncooled catheters (7 Fr) had a large tip electrode (8 mm) and a standard tip electrode (4 mm). RF energy was delivered on isolated porcine myocardium superfused with heparinized pig blood (37 degrees C) at power settings of 10-40 W. Both irrigated systems were characterized by a large lesion depth (8.1 +/- 1.6 mm) and a large lesion diameter (13.8 +/- 1.6 mm). In comparison, internally cooled lesions showed a similar lesion depth (8.0 +/- 1.0 mm), but a significantly smaller lesion diameter (12.3 +/- 1.2 mm,P = 0.04). Large tip lesions had a similar lesion diameter (14.5 +/- 1.6 mm), but a significantly smaller lesion depth (6.3 +/- 1.0 mm,P = 0.002) compared to irrigated lesions. However, lesion volume was not significantly different between the three cooled and the large tip catheter. To induce maximum lesion size, power requirements were three times higher for the irrigation systems and two times higher for the internally cooled and the large tip catheter compared to the standard catheter. Impedance rise was rarest with irrigated and large tip ablation. In case of impedance rise crater formation was a frequent observation (61-93%). Irrigated catheters prevented coagulum formation most effectively. Irrigated rather than internally cooled ablation appears to be most adequate for the induction of deep and

  9. In vitro evaluation of ice-cold saline irrigation during catheter radiofrequency ablation.

    PubMed

    Squara, Fabien; Maeda, Shingo; Aldhoon, Bashar; Marginiere, Julie; Santangeli, Pasquale; Chik, William W; Michele, John; Zado, Erica; Marchlinski, Francis E

    2014-10-01

    Irrigated radiofrequency (RF) catheters allow tissue-electrode interface cooling, decreasing thrombus risk while enabling higher RF power delivery. The impact of irrigation with ice-cold saline (ICS) instead of conventional ambient-temperature saline (ATS) on lesion formation is unknown. We performed 120 RF ablations in vitro on porcine left ventricles, using ICS (<5 °C) or ATS (21 °C) irrigation. For ICS irrigation, the irrigation circuit was cooled externally to maintain delivery of cooled saline at the catheter's tip. We applied 20 g of contact force, and delivered 20 W (irrigation 8 or 17 mL/min) or 30 W (irrigation 17 or 30 mL/min) RF power. Temperatures at tissue-electrode interface and 3-mm depth were assessed by fluoroptic probes. Lesion dimensions were assessed. ICS irrigation cooled the tissue-electrode interface better than ATS (53.9 ± 9.6 °C vs. 63 ± 11.4 °C, P < 0.001). Temperatures at 3-mm depth were similar at 30 W using ICS and ATS (104.2 ± 9.3 °C vs. 105.8 ± 7.3 °C, P = 0.5), but were cooler at 20 W using ICS (71.3 ± 11.6 °C vs. 100.2 ± 11.9 °C, P < 0.001). This translated into smaller lesions at 20 W with ICS versus ATS. At 30 W with 17 mL/min flow rate, lesions had the same depth with ICS and ATS (4.9 ± 0.8 mm vs. 5.4 ± 0.7 mm, P = 0.13) but were narrower with ICS (7.7 ± 0.8 mm vs. 9.3 ± 1.2 mm, P = 0.001). At 30 mL/min, lesions had the same dimensions. Steam pop rate was similar using ICS or ATS irrigation. ICS irrigation more effectively cools tissue-electrode interface than ATS. This may improve RF safety by potentially decreasing thrombus formation, thus facilitating safe ablation at a low saline volume load. However at lower RF power, ICS reduced lesion size compared to ATS. © 2014 Wiley Periodicals, Inc.

  10. Non-fluoroscopic navigation systems for radiofrequency catheter ablation for supraventricular tachycardia reduce ionising radiation exposure

    PubMed Central

    See, Jason; Amora, Jonah L; Lee, Sheldon; Lim, Paul; Teo, Wee Siong; Tan, Boon Yew; Ho, Kah Leng; Lee, Chee Wan; Ching, Chi Keong

    2016-01-01

    INTRODUCTION The use of non-fluoroscopic systems (NFS) to guide radiofrequency catheter ablation (RFCA) for the treatment of supraventricular tachycardia (SVT) is associated with lower radiation exposure. This study aimed to determine if NFS reduces fluoroscopy time, radiation dose and procedure time. METHODS We prospectively enrolled patients undergoing RFCA for SVT. NFS included EnSite™ NavX™ or CARTO® mapping. We compared procedure and fluoroscopy times, and radiation exposure between NFS and conventional fluoroscopy (CF) cohorts. Procedural success, complications and one-year success rates were reported. RESULTS A total of 200 patients over 27 months were included and RFCA was guided by NFS for 79 patients; those with atrioventricular nodal reentrant tachycardia (AVNRT), left-sided atrioventricular reentrant tachycardia (AVRT) and right-sided AVRT were included (n = 101, 63 and 36, respectively). Fluoroscopy times were significantly lower with NFS than with CF (10.8 ± 11.1 minutes vs. 32.0 ± 27.5 minutes; p < 0.001). The mean fluoroscopic dose area product was also significantly reduced with NFS (NSF: 5,382 ± 5,768 mGy*cm2 vs. CF: 21,070 ± 23,311 mGy*cm2; p < 0.001); for all SVT subtypes. There was no significant reduction in procedure time, except for left-sided AVRT ablation (NFS: 79.2 minutes vs. CF: 116.4 minutes; p = 0.001). Procedural success rates were comparable (NFS: 97.5% vs. CF: 98.3%) and at one-year follow-up, there was no significant difference in the recurrence rates (NFS: 5.2% vs. CF: 4.2%). No clinically significant complications were observed in both groups. CONCLUSION The use of NFS for RFCA for SVT is safe, with significantly reduced radiation dose and fluoroscopy time. PMID:26805664

  11. Non-fluoroscopic navigation systems for radiofrequency catheter ablation for supraventricular tachycardia reduce ionising radiation exposure.

    PubMed

    See, Jason; Amora, Jonah L; Lee, Sheldon; Lim, Paul; Teo, Wee Siong; Tan, Boon Yew; Ho, Kah Leng; Lee, Chee Wan; Ching, Chi-Keong

    2016-07-01

    The use of non-fluoroscopic systems (NFS) to guide radiofrequency catheter ablation (RFCA) for the treatment of supraventricular tachycardia (SVT) is associated with lower radiation exposure. This study aimed to determine if NFS reduces fluoroscopy time, radiation dose and procedure time. We prospectively enrolled patients undergoing RFCA for SVT. NFS included EnSiteTM NavXTM or CARTO® mapping. We compared procedure and fluoroscopy times, and radiation exposure between NFS and conventional fluoroscopy (CF) cohorts. Procedural success, complications and one-year success rates were reported. A total of 200 patients over 27 months were included and RFCA was guided by NFS for 79 patients; those with atrioventricular nodal reentrant tachycardia (AVNRT), left-sided atrioventricular reentrant tachycardia (AVRT) and right-sided AVRT were included (n = 101, 63 and 36, respectively). Fluoroscopy times were significantly lower with NFS than with CF (10.8 ± 11.1 minutes vs. 32.0 ± 27.5 minutes; p < 0.001). The mean fluoroscopic dose area product was also significantly reduced with NFS (NSF: 5,382 ± 5,768 mGy*cm2 vs. CF: 21,070 ± 23,311 mGy*cm2; p < 0.001); for all SVT subtypes. There was no significant reduction in procedure time, except for left-sided AVRT ablation (NFS: 79.2 minutes vs. CF: 116.4 minutes; p = 0.001). Procedural success rates were comparable (NFS: 97.5% vs. CF: 98.3%) and at one-year follow-up, there was no significant difference in the recurrence rates (NFS: 5.2% vs. CF: 4.2%). No clinically significant complications were observed in both groups. The use of NFS for RFCA for SVT is safe, with significantly reduced radiation dose and fluoroscopy time. Copyright © Singapore Medical Association.

  12. New-onset ventricular arrhythmias post radiofrequency catheter ablation for atrial fibrillation

    PubMed Central

    Wu, Lingmin; Lu, Yanlai; Yao, Yan; Zheng, Lihui; Chen, Gang; Ding, Ligang; Hou, Bingbo; Qiao, Yu; Sun, Wei; Zhang, Shu

    2016-01-01

    Abstract As a new complication, new-onset ventricular arrhythmias (VAs) post atrial fibrillation (AF) ablation have not been well defined. This prospective study aimed to describe the details of new-onset VAs post AF ablation in a large study cohort. One thousand fifty-three consecutive patients who underwent the first radiofrequency catheter ablation for AF were enrolled. All patients had no evidence of pre-ablation VAs. New-onset VAs were defined as new-onset ventricular tachycardia (VT) or premature ventricular contractions (PVC) ≥1000/24 h within 1 month post ablation. There were 46 patients (4.4%) who had 62 different new-onset VAs, among whom 42 were PVC alone, and 4 were PVC coexisting with nonsustained VT. Multivariate analysis showed that increased serum leukocyte counts ≥50% post ablation were independently associated with new-onset VAs (OR: 1.9; 95% CI: 1.0–3.5; P = 0.043). The median number of PVC was 3161 (1001–27,407) times/24 h. Outflow tract VAs were recorded in 35 (76.1%) patients. No significant differences were found in origin of VAs (P = 0.187). VAs disappeared without any treatment in 6 patients (13.0%). No VAs-related adverse cardiac event occurred. The study revealed a noticeable prevalence but relatively benign prognosis of new-onset VAs post AF ablation. Increased serum leukocyte counts ≥50% post ablation appeared to be associated with new-onset VAs, implying that inflammatory response caused by ablation might be the mechanism. PMID:27603357

  13. Cost comparison of radiofrequency catheter ablation versus cryoablation for atrial fibrillation in hospitals using both technologies.

    PubMed

    Hunter, Tina D; Palli, Swetha R; Rizzo, John A

    2016-10-01

    The objective of this study was to compare the cost of radiofrequency (RF) ablation vs cryoablation (Cryo) for atrial fibrillation (AF). This retrospective cohort study used 2013-2014 records from the Premier Healthcare Database for adults with AF catheter ablation. Exclusions included non-AF ablation, surgical ablation, valve replacement or repair, or cardiac implant. Hospitals were required to perform ≥20 procedures using each technology, with the technology identifiable in at least 90% of cases. The primary endpoint was total variable visit cost, modeled separately for inpatient and outpatient visits, and adjusted for patient and hospital characteristics. Technology was categorized as RF or Cryo, with dual-technology procedures classified as Cryo. The Cryo cohort was further divided into Cryo only and Cryo with RF for sensitivity analyses. A composite adverse event endpoint was also compared. A total of 1261 RF procedures and 1276 Cryo procedures, of which 500 also used RF, met study criteria. RF patients were slightly older and sicker, and had more cardiovascular disease and additional arrhythmias. Adjusted inpatient costs were $2803 (30.0%) higher for Cryo, and adjusted outpatient costs were $2215 (19.5%) higher. Sensitivity models showed higher costs in both Cryo sub-groups compared with RF. Procedural complication rates were not significantly different between cohorts (p-values: 0.4888 inpatient, 0.5072 outpatient). AF ablation using RF results in significantly lower costs compared with Cryo, despite an RF population with more cardiovascular disease. This saving cannot be attributed to a difference in complication rates.

  14. Atrial conduction delay predicts atrial fibrillation in paroxysmal supraventricular tachycardia patients after radiofrequency catheter ablation.

    PubMed

    Xu, Zhen-Xing; Zhong, Jing-Quan; Zhang, Wei; Yue, Xin; Rong, Bing; Zhu, Qing; Zheng, Zhaotong; Zhang, Yun

    2014-06-01

    This study aimed to assess whether intra- and inter-atrial conduction delay could predict atrial fibrillation (AF) for paroxysmal supraventricular tachycardia (PSVT) patients after successful treatment by radiofrequency catheter ablation (RFCA). Echocardiography examination was performed on 524 consecutive PSVT patients (15 patients were excluded). Left atrial dimension, right atrial diameter and intra- and inter-atrial conduction delay were measured before ablation. Patients were divided into group A (n = 32): occurrence of AF after the ablation and group B (n = 477): remained in sinus rhythm during follow-up. Receiver operating characteristic (ROC) curve analysis was performed to estimate the predictive value of intra- and inter-atrial conduction delay. Both intra- and inter-atrial conduction delay were higher in group A than in group B (4.79 ± 0.30 msec vs. 4.56 ± 0.32 msec; 21.98 ± 1.32 msec vs. 20.01 ± 1.33; p < 0.05). Binary logistic regression analysis showed that intra- and inter-atrial conduction were significant influential factors for the occurrence of AF (odds ratio [OR] = 13.577, 95% confidence interval [CI], 3.469-48.914; OR = 2.569, 95% CI, 1.909-3.459, p < 0.05). The ROC cure analysis revealed that intra-atrial conduction delay ≥ 4.45 msec and inter-atrial conduction delay ≥ 20.65 were the most optimal cut-off value for predicting AF in PSVT patients after RFCA. In conclusion, this is the first study to show that the intra- and inter-atrial conduction delay could effectively predict AF in post-ablation PSVT patients.

  15. Pain perception during esophageal warming due to radiofrequency catheter ablation in the left atrium.

    PubMed

    Galeazzi, Marco; Ficili, Sabina; Dottori, Serena; Elian, Mohamed Abdelkader; Pasceri, Vincenzo; Venditti, Franco; Russo, Maurizio; Lavalle, Carlo; Pandozi, Angela; Pandozi, Claudio; Santini, Massimo

    2010-03-01

    We investigated the relationship among esophageal warming, pain perception, and the site of radiofrequency (RF) delivery in the left atrium (LA) during the course of catheter ablation of atrial fibrillation. Such a procedure in awake patients is often linked to the development of visceral pain and esophageal warming. As a consequence, potentially dangerous complications have been described. Twenty patients undergoing RF ablation in the LA were studied. An esophageal probe (EP) capable of measuring endoesophageal temperature (ET) was positioned before starting the procedure. The relative position of the EP and the tip of the ablator were evaluated through fluoroscopy imaging before starting each RF delivery, during which the highest value of the temperature was collected. After RF withdrawal, the patients were asked to define the intensity of the experienced pain by using a score index ranging from 0 (no pain) to 4 (pain requiring immediate RF interruption). The mean ET value during ablation was 39.59 +/- 4.71 degrees C. The EP proximity to the ablator's tip showed a high correlation with the development of the highest ET values (Spearman's rank correlation coefficient r = 0.49, confidence interval (CI) 0.55-0.41). Moreover, the highest values of pain intensity were reported when the RF was delivered to the atrial zones close to the EP projection (r = 0.50, CI 0.55-0.42) and when the highest ET levels were reached (r = 0.38, CI 0.30-0.45). Pain perception in LA ablation is significantly related to esophageal warming and is higher when the RF is delivered near the esophagus. It seems advisable to perform ET monitoring in sedated patients to avoid short- and long-term jeopardizing of the esophageal wall.

  16. [Clinical analysis of 19 cases of pregnant women with rapid arrhythmia in the treatment of radiofrequency catheter ablation].

    PubMed

    Chu, L; Zhang, J; Li, Y N; Long, D Y

    2016-10-25

    Objective: To investigate the risk of radiofrequency catheter ablation and maternal and infant in pregnant women with rapid arrhythmia during pregnancy. Methods: The clinical data of the 19 cases of pregnancy complicated with rapid arrhythmia were retrospectively analyzed and followed up, including the gestational week, the type of arrhythmia, the treatment, and the outcome of the mother and child in Beijing Anzhen Hospital of Capital Medical University from January 2002 to March 2016. Results: (1)Clinical characteristics: the ages of the 19 cases were(31±4)years old(ranged from 26 to 35 years old), the onset gestational ages were(21±4)weeks(ranged from 15 to 32 weeks).

  17. Near-infrared spectroscopy integrated catheter for characterization of myocardial tissues: preliminary demonstrations to radiofrequency ablation therapy for atrial fibrillation

    PubMed Central

    Singh-Moon, Rajinder P.; Marboe, Charles C.; Hendon, Christine P.

    2015-01-01

    Effects of radiofrequency ablation (RFA) treatment of atrial fibrillation can be limited by the ability to characterize the tissue in contact. Parameters obtained by conventional catheters, such as impedance and temperature can be insufficient in providing physiological information pertaining to effective treatment. In this report, we present a near-infrared spectroscopy (NIRS)-integrated catheter capable of extracting tissue optical properties. Validation experiments were first performed in tissue phantoms with known optical properties. We then apply the technique for characterization of myocardial tissues in swine and human hearts, ex vivo. Additionally, we demonstrate the recovery of critical parameters relevant to RFA therapy including contact verification, and lesion transmurality. These findings support the application of NIRS for improved guidance in RFA therapeutic interventions. PMID:26203376

  18. Long-Term Success of Irrigated Radiofrequency Catheter Ablation of Sustained Ventricular Tachycardia: Post-Approval THERMOCOOL VT Trial.

    PubMed

    Marchlinski, Francis E; Haffajee, Charles I; Beshai, John F; Dickfeld, Timm-Michael L; Gonzalez, Mario D; Hsia, Henry H; Schuger, Claudio D; Beckman, Karen J; Bogun, Frank M; Pollak, Scott J; Bhandari, Anil K

    2016-02-16

    Radiofrequency catheter ablation is used to treat recurrent ventricular tachycardia (VT). This study evaluated long-term safety and effectiveness of radiofrequency catheter ablation using an open-irrigated catheter. Patients with sustained monomorphic ventricular tachycardia associated with coronary disease were analyzed for cardiovascular-specific adverse events within 7 days of treatment, hospitalization duration, 6-month sustained monomorphic ventricular tachycardia recurrence, quality of life measured by the Hospital Anxiety and Depression Scale, long-term (1-, 2-, and 3-year) survival, symptomatic VT control, and amiodarone use. Overall, 249 patients, mean age 67.4 years, were enrolled. The cardiovascular-specific adverse events rate was 3.9% (9 of 233) with no strokes. Noninducibility of targeted VT was achieved in 75.9% of patients. Post-ablation median hospitalization was 2 days. At 6 months, 62.0% (114 of 184) of patients had no sustained monomorphic ventricular tachycardia recurrence; the proportion of patients with implantable cardioverter-defibrillator shocks decreased from 81.2% to 26.8% (p < 0.0001); the frequency of VT in implantable cardioverter-defibrillator patients with recurrences was reduced by ≥50% in 63.8% of patients; and the proportion with normal Hospital Anxiety and Depression Scale scores increased from 48.8% to 69.1% (p < 0.001). Patient-reported VT remained steady for 1, 2, and 3 years at 22.7%, 29.8%, and 24.1%, respectively. Amiodarone use and hospitalization decreased from 55% and 77.2% pre-ablation to 23.3% and 30.7%, 18.5% and 36.7%, 17.7% and 31.3% at 1, 2, and 3 years, respectively. Radiofrequency catheter ablation reduced implantable cardioverter-defibrillator shocks and VT episodes and improved quality of life at 6 months. A steady 3-year nonrecurrence rate with reduced amiodarone use and hospitalizations indicate improved long-term outcomes. (NaviStar ThermoCool Catheter for Endocardial RF Ablation in Patients With

  19. Novel contact force sensor incorporated in irrigated radiofrequency ablation catheter predicts lesion size and incidence of steam pop and thrombus.

    PubMed

    Yokoyama, Katsuaki; Nakagawa, Hiroshi; Shah, Dipen C; Lambert, Hendrik; Leo, Giovanni; Aeby, Nicolas; Ikeda, Atsushi; Pitha, Jan V; Sharma, Tushar; Lazzara, Ralph; Jackman, Warren M

    2008-12-01

    An open-irrigated radiofrequency (RF) ablation catheter was developed to measure contact force (CF). Three optical fibers measure microdeformation of the catheter tip. The purpose of this study was to (1) validate the accuracy of CF sensor (CFS) (bench test); and (2) determine the relationship between CF and tissue temperatures, lesion size, steam pop, and thrombus during RF ablation using a canine thigh muscle preparation. CFS measurements (total 1409) from 2 catheters in 3 angles (perpendicular, parallel, and 45 degrees ) were compared with a certified balance (range, 0 to 50 g). CFS measurements correlated highly (R(2) > or =0.988; mean error, < or =1.0 g). In 10 anesthetized dogs, a skin cradle over the thigh muscle was superfused with heparinized blood at 37 degrees C. A 7F catheter with 3.5-mm saline-irrigated electrode and CFS (Endosense) was held perpendicular to the muscle at CF of 2, 10, 20, 30, and 40 g. RF was delivered (n=100) for 60 seconds at 30 or 50 W (irrigation 17 or 30 mL/min). Tissue temperature (3 and 7 mm depths), lesion size, thrombus, and steam pop increased significantly with increasing CF at each RF power. Lesion size was greater with applications of lower power (30 W) and greater CF (30 to 40 g) than at high power (50 W) with lower CF (2 to 10 g). This novel ablation catheter, which accurately measures CF, confirmed CF is a major determinant of RF lesion size. Steam pop and thrombus incidence also increases with CF. CFS in an open-irrigated ablation catheter that may optimize the selection of RF power and application time to maximize lesion formation and reduce the risk of steam pop and thrombus.

  20. Efficacy of an Anatomical Approach in Radiofrequency Catheter Ablation of Idiopathic Ventricular Arrhythmias Originating From the Left Ventricular Outflow Tract.

    PubMed

    Yamada, Takumi; Yoshida, Naoki; Doppalapudi, Harish; Litovsky, Silvio H; McElderry, H Thomas; Kay, G Neal

    2017-05-01

    When anatomic obstacles preclude radiofrequency catheter ablation of idiopathic ventricular arrhythmias (VAs) originating from the left ventricular outflow tract (LVOT), an alternative approach from the anatomically opposite side (endocardial versus epicardial or above versus below the aortic valve) may be considered (anatomic ablation). The purpose of this study was to investigate the efficacy of an anatomic ablation in idiopathic LVOT VAs. We studied 229 consecutive patients with idiopathic LVOT VAs. Radiofrequency ablation from the first suitable site was successful in 190 patients, and in the remaining 39 patients, it was unsuccessful or had to be abandoned because of anatomic obstacles. In 22 of these 39 patients, an anatomic ablation was successful, and the VA origins were located in the intramural LVOT in 17 patients, basal left ventricular summit in 4, and LVOT septum near the His bundle in 1. The anatomic ablation was highly successful for idiopathic VAs originating from the intramural LVOT (>75%) and lateral LVOT, whereas it was unlikely to be successful for idiopathic VAs originating from the basal left ventricular summit (25%) and sepal LVOT. When a standard catheter ablation targeting the best electrophysiological measure of idiopathic LVOT VAs was unsuccessful or had to be abandoned because of anatomic obstacles, an anatomic ablation was moderately successful. These idiopathic LVOT VAs with a successful anatomic ablation commonly arose from the intramural LVOT among the left coronary cusp, aortomitral continuity, and epicardium, occasionally the basal left ventricular summit, and rarely the LVOT septum near the His bundle. © 2017 American Heart Association, Inc.

  1. [Radiofrequency catheter ablation in children with Wolff-Parkinson-White syndrome and sudden cardiac death who had been resuscitated].

    PubMed

    Benito Bartolomé, F; Sánchez Fernández-Bernal, C

    2001-04-01

    Sudden death may be the first manifestation of the Wolff-Parkinson-White syndrome, especially in children and adolescents. The aim of this study was to evaluate the usefulness of radiofrequency catheter ablation in children with Wolff-Parkinson-White syndrome with aborted sudden death. We report four patients with Wolff-Parkinson-White syndrome who survived cardiac arrest. The patients were aged from 2.5 months to 16 years. The two first patients were lactating infants; in the first sudden death occurred during digoxin treatment for supraventricular tachycardia secondary to Wolff-Parkinson-White syndrome and in the second the syndrome was diagnosed after an episode of sudden death. In these patients a free wall accessory pathway (left posterior and left lateral, respectively) was successfully ablated using a transseptal approach. The third patient was diagnosed with asymptomatic Wolff-Parkinson-White syndrome; sudden death occurred during exercise. In the fourth patient, sudden death occurred after intravenous therapy with adenosine triphosphate and amiodarone for rapid atrial fibrillation. In both patients, one accessory pathway, located in right posteroseptal and right anterior free wall, respectively, was ablated. After a mean follow-up of 43.5 26.4 months, no recurrence of sudden death had occurred and electrocardiogram showed sinus rhythm without delta wave. The third patient presented severe sequelae of hypoxemic encephalopathy, which persisted during the follow-up. Radiofrequency catheter ablation is the treatment of choice in Wolff-Parkinson-White syndrome with episodes of aborted sudden death.

  2. Effect of Irrigant Characteristics on Lesion Formation After Radiofrequency Energy Delivery Using Ablation Catheters with Actively Cooled Tips.

    PubMed

    Nguyen, Duy T; Olson, Matthew; Zheng, Lijun; Barham, Waseem; Moss, Joshua D; Sauer, William H

    2015-07-01

    The delivery of radiofrequency (RF) energy through irrigated ablation catheters may be affected by irrigant osmolarity and by catheter position. We sought to characterize lesion formation characteristics using different irrigants in both open and closed irrigated catheter. An ex vivo model consisting of viable bovine myocardium and a submersible load cell was assembled in a circulating saline bath at 37°C. An externally irrigated ablation catheter and a closed irrigated catheter were positioned with 10 g of force in both perpendicular and parallel positions. A series of ablation lesions using different irrigants were delivered using a constant rate of irrigation (30 cc/min) at 50 W. Potential clinical applicability was evaluated in vivo by targeting porcine epicardium with different irrigants during open irrigation ablation and assessing lesion sizes. Ablation in the perpendicular position produced significantly larger lesions for all irrigants, compared to their respective parallel position ablation. For both open and closed irrigated ablation, half normal saline (HNS) ablation created larger lesions than normal saline (NS), and dextrose water (D5W) lesions were significantly larger than both HNS and NS lesions. Steam pops were mostly observed in the perpendicular position, and the rate of steam pops was statistically higher only for open irrigated D5W, but not for HNS, when compared to NS. Both open and closed irrigated ablation with D5W and HNS in the parallel position created larger lesions than parallel NS ablation without causing more steam pops. In an in vivo porcine model, open irrigated ablation with D5W created larger lesions compared to standard NS irrigation. In ex vivo and in vivo models, decreased osmolarity and charge density increased RF energy delivery to tissue, resulting in larger lesions for both open and closed irrigated ablations. A perpendicular catheter position created larger lesions across all irrigants for both open and closed irrigation

  3. Results of Cryoenergy and Radiofrequency-Based Catheter Ablation for Treating Ventricular Arrhythmias Arising From the Papillary Muscles of the Left Ventricle, Guided by Intracardiac Echocardiography and Image Integration.

    PubMed

    Rivera, Santiago; Ricapito, Maria de la Paz; Tomas, Leandro; Parodi, Josefina; Bardera Molina, Guillermo; Banega, Rodrigo; Bueti, Pablo; Orosco, Agustin; Reinoso, Marcelo; Caro, Milagros; Belardi, Diego; Albina, Gaston; Giniger, Alberto; Scazzuso, Fernando

    2016-04-01

    Catheter radiofrequency ablation of ventricular arrhythmias (VAs) arising from the left ventricle's papillary muscles has been associated with inconsistent results. The use of cryoenergy versus radiofrequency has not been compared yet. This study compares outcomes and complications of catheter ablation of VA from the papillary muscles of the left ventricle with either cryoenergy or radiofrequency. Twenty-one patients (40±12 years old; 47% males; median ejection fraction 59±7.3%) with drug refractory premature ventricular contractions or ventricular tachycardia underwent catheter cryoablation or radiofrequency ablation. VAs were localized using 3-dimensional mapping, multidetector computed tomography, and intracardiac echocardiography, with arrhythmia foci being mapped at either the anterolateral papillary muscle or posteromedial papillary muscles of the left ventricle. Focal ablation was performed using an 8-mm cryoablation catheter or a 4-mm open-irrigated radiofrequency catheter, via transmitral approach. Acute success rate was 100% for cryoenergy (n=12) and 78% for radiofrequency (n=9; P=0.08). Catheter stability was achieved in all patients (100%) treated with cryoenergy, and only in 2 (25%) patients treated with radiofrequency (P=0.001). Incidence of multiple VA morphologies was observed in 7 patients treated with radiofrequency (77.7%), whereas none was observed in those treated with cryoenergy (P=0.001). VA recurrence at 6 months follow-up was 0% for cryoablation and 44% for radiofrequency (P=0.03). Cryoablation was associated with higher success rates and lower recurrence rates than radiofrequency catheter ablation, better catheter stability, and lesser incidence of polymorphic arrhythmias. © 2016 American Heart Association, Inc.

  4. Development of a simultaneous cryo-anchoring and radiofrequency ablation catheter for percutaneous treatment of mitral valve prolapse.

    PubMed

    Boronyak, Steven M; Merryman, W David

    2012-09-01

    Mitral valve prolapse (MVP) is one subtype of mitral valve (MV) disease and is often characterized by enlarged leaflets that are thickened and have disrupted collagen architecture. The increased surface area of myxomatous leaflets with MVP leads to mitral regurgitation, and there is need for percutaneous treatment options that avoid open-chest surgery. Radiofrequency (RF) ablation is one potential therapy in which resistive heating can be used to reduce leaflet size via collagen contracture. One challenge of using RF ablation to percutaneously treat MVP is maintaining contact between the RF ablation catheter tip and a functioning MV leaflet. To meet this challenge, we have developed a RF ablation catheter with a cryogenic anchor for attachment to leaflets in order to apply RF ablation. We demonstrate the effectiveness of the dual-energy catheter in vitro by examining changes in leaflet biaxial compliance, thermal distribution with infrared (IR) imaging, and cryogenic anchor strength. We report that 1250 J of RF energy with cryo-anchoring reduced the determinant of the deformation gradient tensor at systolic loading by 23%. IR imaging revealed distinct regions of cryo-anchoring and tissue ablation, demonstrating that the two modalities do not counteract one another. Finally, cryogenic anchor strength to the leaflet was reduced but still robust during the application of RF energy. These results indicate that a catheter having combined RF ablation and cryo-anchoring provides a novel percutaneous treatment strategy for MVP and may also be useful for other percutaneous procedures where anchored ablation would provide more precise spatial control.

  5. Radiofrequency delivery through a cooled catheter tip allows the creation of larger endomyocardial lesions in the ovine heart.

    PubMed

    Ruffy, R; Imran, M A; Santel, D J; Wharton, J M

    1995-12-01

    The delivery of radiofrequency (RF) energy through conventional catheter electrodes is often associated with coagulation necrosis at the tissue-electrode interface, with resultant impedance rise and limited lesion size. This study was performed to examine the effects of catheter tip cooling during RF delivery, to test the hypothesis that such cooling would decrease the likelihood if impedance rise and allow the creation of larger endomyocardial lesions. The experiments were performed in eight open chest, anesthetized sheep. RF lesions were created within both ventricular chambers of each animal through a catheter tip that could be cooled with a saline perfusate. Assignment of cooled versus noncooled RF delivery to either ventricle was alternated from one animal to the next. In each set of experiments, lesion volumes relative to the mode of RF delivery were compared. The mean power delivered via the cooled electrode (22.04 +/- 4.51 W) was significantly higher than that delivered via the noncooled electrode (6.10 +/- 2.47 W; P < 0.001). The mean duration of RF delivery was 42.7 +/- 11.2 sec for noncooled lesions versus 49.2 +/- 6.8 sec for cooled lesions (P < 0.01). Mean lesion volume was 436.07 +/- 177.00 mm3 for noncooled RF delivery versus 1247.78 +/- 520.51 mm3 for cooled RF delivery (P < 0.001). This significantly larger lesion size with cooled RF delivery was associated with no instance of impedance rise in 27 attempts versus 11 impedance rises in 28 attempts with noncooled RF (P < 0.001). Delivery of RF energy through a cooled catheter tip allows the creation of larger endomyocardial lesions by limiting the occurrence of impedance rise despite the delivery of greater energy. These observations suggest that, under certain conditions, resistive tissue heating at a distance from the site of current delivery may play an important role in RF ablation therapy.

  6. Optoacoustic monitoring of real-time lesion formation during radiofrequency catheter ablation

    NASA Astrophysics Data System (ADS)

    Pang, Genny A.; Bay, Erwin; Deán-Ben, Xosé L.; Razansky, Daniel

    2015-03-01

    Current radiofrequency cardiac ablation procedures lack real-time lesion monitoring guidance, limiting the reliability and efficacy of the treatment. The objective of this work is to demonstrate that optoacoustic imaging can be applied to develop a diagnostic technique applicable to radiofrequency ablation for cardiac arrhythmia treatment with the capabilities of real-time monitoring of ablated lesion size and geometry. We demonstrate an optoacoustic imaging method using a 256-detector optoacoustic imaging probe and pulsed-laser illumination in the infrared wavelength range that is applied during radiofrequency ablation in excised porcine myocardial tissue samples. This technique results in images with high contrast between the lesion volume and unablated tissue, and is also capable of capturing time-resolved image sequences that provide information on the lesion development process. The size and geometry of the imaged lesion were shown to be in excellent agreement with the histological examinations. This study demonstrates the first deep-lesion real-time monitoring for radiofrequency ablation generated lesions, and the technique presented here has the potential for providing critical feedback that can significantly impact the outcome of clinical radiofrequency ablation procedures.

  7. [Catheter ablation for paroxysmal atrial fibrillation: new generation cryoballoon or contact force sensing radiofrequency ablation?].

    PubMed

    Nagy, Zsófia; Kis, Zsuzsanna; Som, Zoltán; Földesi, Csaba; Kardos, Attila

    2016-05-29

    Contact force sensing radiofrequency ablation and the new generation cryoballoon ablation are prevalent techniques for the treatment of paroxysmal atrial fibrillation. The authors aimed to compare the procedural and 1-year outcome of patients after radiofrequency and cryoballoon ablation. 96 patients with paroxysmal atrial fibrillation (radiofrequency ablation: 58, cryoballoon: 38 patients; 65 men and 31 women aged 28-70 years) were enrolled. At postprocedural 1, 3, 6 and 12 months ECG, Holter monitoring and telephone interviews were performed. Procedure and fluorosocopy time were: radiofrequency ablation, 118.5 ± 15 min and 15.8 ± 6 min; cryoballoon, 73.5 ± 16 min (p<0.05) and 13.8 ± 4.,1 min (p = 0.09), respectively. One year later freedom from atrial fibrillation was achieved in 76.5% of patients who underwent radiofrequency ablation and in 81% of patients treated with cryoballoon. Temporary phrenic nerve palsy occurred in two patients and pericardial tamponade developed in one patient. In this single center study freedom from paroxysmal atrial fibrillation was similar in the two groups with significant shorter procedure time in the cryoballoon group.

  8. Teflon-buttressed sutures plus pericardium patch repair left ventricular rupture caused by radiofrequency catheter ablation: A case report.

    PubMed

    Cao, Hao; Zhang, Qi; He, Yanzhong; Feng, Xiaodong; Liu, Zhongmin

    2016-09-01

    Cardiac rupture often occurs after myocardial infarction or chest trauma with a high mortality rate. However, left ventricular rupture caused by radiofrequency catheter ablation (RFCA) is extremely rare. We describe a case of a 61-year-old male who survived from left ventricular rupture caused by a RFCA procedure for frequent ventricular premature contractions. Surgical exploration with cardiopulmonary bypass (CPB) was performed when the signs of cardiac tamponade developed 7 hours after the ablation surgery. Teflon-buttressed sutures of the tear in the left ventricular posterolateral wall and pericardium patch applied to the contusion region on the wall repaired the rupture safely and effectively. Timely surgical intervention under CPB facilitated the survival of the patient. Teflon-buttressed sutures plus pericardium patch achieved the successful repair of the rupture.

  9. Contact Geometry Affects Lesion Formation in Radio-Frequency Cardiac Catheter Ablation

    PubMed Central

    Gallagher, Neal; Fear, Elise C.; Byrd, Israel A.; Vigmond, Edward J.

    2013-01-01

    One factor which may be important for determining proper lesion creation during atrial ablation is catheter-endocardial contact. Little information is available that relates geometric contact, depth and angle, to ablation lesion formation. We present an electrothermal computer model of ablation that calculated lesion volume and temperature development over time. The Pennes bioheat equation was coupled to a quasistatic electrical problem to investigate the effect of catheter penetration depth, as well as incident catheter angle as may occur in practice. Biological experiments were performed to verify the modelling of electrical phenomena. Results show that for deeply penetrating tips, acute catheter angles reduced the rate of temperature buildup, allowing larger lesions to form before temperatures elevated excessively. It was also found that greater penetration did not lead to greater transmurality of lesions. We conclude that catheter contact angle plays a significant role in lesion formation, and the time course must be considered. This is clinically relevant because proper identification and prediction of geometric contact variables could improve ablation efficacy. PMID:24086275

  10. Radiofrequency Catheter Ablation Targeting the Vein of Marshall in Difficult Mitral Isthmus Ablation or Pulmonary Vein Isolation.

    PubMed

    Lee, Ji Hyun; Nam, Gi-Byoung; Kim, Minsu; Hwang, You Mi; Hwang, Jongmin; Kim, Jun; Choi, Kee-Joon; Kim, You-Ho

    2017-04-01

    The ligament of Marshall may hinder the creation of mitral isthmus (MI) block or pulmonary vein (PV) isolation (PVI) in radiofrequency (RF) catheter ablation of atrial fibrillation (AF). We aimed to assess the benefit of RF ablation targeting the vein of Marshall (VOM) in failed cases of MI block or PVI. We reviewed the medical records of patients who underwent RF ablation targeting the VOM after failed MI ablation or left PVI using the conventional method, which included circumferential point-by-point ablation around the PV antrum and carina for PVI, and endocardial MI and epicardial distal coronary sinus (CS) ablation for MI block. The VOM was identified by using selective VOM venography with an external irrigation RF ablation catheter. RF ablation targeting the VOM was performed with RF application at the ostium of the VOM inside the CS or at the endocardial region facing the VOM course. During the set period, CS venography was performed in 42 patients after failure of left PVI (n = 5) or MI block (n = 37). Under CS venography, the VOM was visualized in 22 of 42 patients (MI = 19 and PVI = 3). During selective venography of the VOM, no procedure-related complication was observed. RF application targeting the VOM successfully achieved MI block in 13 patients (68.4%) and PVI in 2 patients (66.7%). Selective VOM venography using an irrigated ablation catheter is feasible and safe. RF ablation targeting the VOM may provide additional benefit in failed cases of MI block or PVI. © 2017 Wiley Periodicals, Inc.

  11. PATH OPTIMIZATION AND CONTROL OF A SHAPE MEMORY ALLOY ACTUATED CATHETER FOR ENDOCARDIAL RADIOFREQUENCY ABLATION

    PubMed Central

    Wiest, Jennifer H.; Buckner, Gregory D.

    2014-01-01

    This paper introduces a real-time path optimization and control strategy for shape memory alloy (SMA) actuated cardiac ablation catheters, potentially enabling the creation of more precise lesions with reduced procedure times and improved patient outcomes. Catheter tip locations and orientations are optimized using parallel genetic algorithms to produce continuous ablation paths with near normal tissue contact through physician-specified points. A nonlinear multivariable control strategy is presented to compensate for SMA hysteresis, bandwidth limitations, and coupling between system inputs. Simulated and experimental results demonstrate efficient generation of ablation paths and optimal reference trajectories. Closed-loop control of the SMA-actuated catheter along optimized ablation paths is validated experimentally. PMID:25684857

  12. Heat distribution and heat transport in bone during radiofrequency catheter ablation.

    PubMed

    Rachbauer, F; Mangat, J; Bodner, G; Eichberger, P; Krismer, M

    2003-04-01

    To assess the feasibility of percutaneous radiofrequency ablation in large bone tumours, the heat distribution in cortical bone and marrow around inserted electrodes was measured. Fresh bovine cadaver tibial bones were locally heated through drill holes for a maximum of half an hour using water-cooled single radiofrequency electrodes (Radionics Instruments Inc) by pulsed energy. Temperatures were measured in the marrow canal as well as in cortical bone by thermocouples at various distances from the inserted probes. Perpendicular to the probe, hyperthermia of more than 50 degrees C could be created in bone marrow in a sphere of approximately 3 cm, and of approximately 1 cm in cortical bone. As irreversible cellular damage can be expected when increasing the temperature to 50 degrees C for a duration of 6 min, this method may be effective for the minimal invasive ablation of neoplasms within human bone in cigar-shaped regions of approximately 3-cm diameter.

  13. Acute myocardial infarction after radiofrequency catheter ablation of typical atrial flutter.

    PubMed

    Yune, Sehyo; Lee, Woo Joo; Hwang, Ji-won; Kim, Eun; Ha, Jung Min; Kim, June Soo

    2014-02-01

    A 53-yr-old man underwent radiofrequency ablation to treat persistent atrial flutter. After the procedure, the chest pain was getting worse, and the electrocardiogram showed ST-segment elevation in inferior leads with reciprocal changes. Immediate coronary angiography showed total occlusion with thrombi at the distal portion of the right coronary artery, which was very close to the ablation site. Intervention with thrombus aspiration and balloon dilatation was successful, and the patient recovered without any kind of sequelae. Although the exact mechanism is obscure, the most likely explanation is a thermal injury to the vascular wall that ruptured into the lumen and formed thrombus. Vasospasm and thromboembolism can also be other possibilities. This case raise the alarm to cardiologists who perform radiofrequency ablation to treat various kinds of cardiac arrhythmias, in that myocardial infarction has been rarely considered one of the complications.

  14. Renal sympathetic denervation using an externally irrigated radiofrequency ablation catheter for treatment of resistant hypertension – Acute safety and short term efficacy

    PubMed Central

    Yalagudri, Sachin; Raju, Narayana; Das, Bharati; Daware, Ashwin; Maiya, Shreesha; Jothiraj, Kannan; Ravikishore, A.G.

    2015-01-01

    Objectives This study was conducted to assess the acute safety and short term efficacy of renal sympathetic denervation (RSDN) using solid tip radiofrequency ablation (RFA) catheter and saline irrigation through the renal guiding catheter to achieve effective denervation. Background RSDN using a specialized solid-tip RFA catheter has recently been demonstrated to safely reduce systemic blood pressure in patients with refractory hypertension, the limitation being inadequate power delivery in renal arteries. So, we used solid-tip RFA catheter along with saline irrigation for RSDN. Methods Nine patients with resistant hypertension underwent CT and conventional renal angiography, followed by bilateral or unilateral RSDN using 5F RFA catheter with saline irrigation through renal guiding catheter. Repeat renal angiography was performed at the end of the procedure. In all patients, pre- and post-procedure serum creatinine was measured. Results Over 1-month period: 1) the systolic/diastolic blood pressure decreased by −57 ± 20/−25 ± 7.5 mm Hg; 2) all patients experienced a decrease in systolic blood pressure of at least −36 mm Hg (range 36–98 mm Hg); 3) there was no evidence of renal artery injury immediate post-procedure. There was no significant change in serum creatinine level. Conclusions This data shows the acute procedural safety and short term efficacy of RSDN using modified externally irrigated solid tip RFA catheter. PMID:26138176

  15. Restoration of Atrial Mechanical Function after Successful Radio-Frequency Catheter Ablation of Atrial Flutter

    PubMed Central

    Rhee, Kyoung-Suk; Kang, Duk-Hyun; Song, Jae-Kwan; Nam, Gi-Byoung; Choi, Kee-Joon; Kim, You-Ho

    2001-01-01

    Background: Atrial mechanical dysfunction and its recovery time course after successful radiofrequency ablation of chronic atrial flutter (AFL) has been largely unknown. We serially evaluated left atrial function by echocardiography after successful ablation of chronic atrial flutter. Methods: In 13 patients with chronic AFL, mitral E wave A wave, and the ratio of A/E velocity were measured at 1 day, 1 month, 3 months and 6–12 months after successful radiofrequency (RF) ablation. Doppler tissue imaging (DTI) technique was also used to avoid load-dependent variation in the flow velocity pattern. Results: Left atrial mechanical function, assessed by A wave velocity and the annular motion, was depressed at 1 day, but improved significantly at 1 month and maintained through 6–12 months after the ablation. Left atrial size did not change significantly. Conclusion: Left atrial mechanical function was depressed immediately after successful RF ablation of chronic AFL, but it improved significantly after 1 month and was maintained over one year. PMID:11590904

  16. Clinical course of arrhythmogenic right ventricular cardiomyopathy in the era of implantable cardioverter-defibrillators and radiofrequency catheter ablation.

    PubMed

    Komura, Masatoshi; Suzuki, Jun-Ichi; Adachi, Susumu; Takahashi, Atsushi; Otomo, Kenichiro; Nitta, Junichi; Nishizaki, Mitsuhiro; Obayashi, Tohru; Nogami, Akihiko; Satoh, Yasuhiro; Okishige, Kaoru; Hachiya, Hitoshi; Hirao, Kenzo; Isobe, Mitsuaki

    2010-01-01

    This study investigated the clinical course of arrhythmogenic right ventricular cardiomyopathy (ARVC) patients and in particular evaluated the contribution of radiofrequency catheter ablation (RFCA) and an implantable cardioverter-defibrillator (ICD) to the treatment of ARVC. ARVC is a myocardial disorder and a cause of sudden cardiac death due to ventricular tachycardia (VT). Little is known about its prognosis in Japanese ARVC patients. Thirty-five ARVC patients were studied. Mean age of patients whose onset of ARVC was congestive heart failure (CHF) (66.0 +/- 4.0 years) was significantly higher than those whose onset was VT (44.5 +/- 14.8 years, P < 0.05). ARVC patients with CHF onset showed significantly higher death rates compared to those with VT onset. ICD treatment significantly reduced episodes of hospitalization due to VT (0.1 +/- 0.4 episodes) in comparison to treatment by RFCA (1.7 +/- 2.2 episodes, P < 0.03). RFCA treatment did not reduce recurrence of VT in the follow-up period. ICD therapy showed comparable mortality to RFCA treatment. The prognosis of ARVC with CHF onset is poor. ICD therapy significantly reduced hospitalization due to VT compared with RFCA treatment. ICD implantation in combination with medication may be a better treatment for ARVC.

  17. Incidence and Factors Predicting Skin Burns at the Site of Indifferent Electrode during Radiofrequency Catheter Ablation of Cardiac Arrhythmias

    PubMed Central

    Ibrahim, Hussain; Finta, Bohuslav; Rind, Jubran

    2016-01-01

    Radiofrequency catheter ablation (RFA) has become a mainstay for treatment of cardiac arrhythmias. Skin burns at the site of an indifferent electrode patch have been a rare, serious, and likely an underreported complication of RFA. The purpose of this study was to determine the incidence of skin burns in cardiac RFA procedures performed at one institution. Also, we wanted to determine the factors predicting skin burns after cardiac RFA procedures at the indifferent electrode skin pad site. Methods. A retrospective case control study was performed to compare the characteristics in patients who developed skin burns in a 2-year period. Results. Incidence of significant skin burns after RFA was 0.28% (6/2167). Four of the six patients were female and all were Caucasians. Four controls for every case were age and sex matched. Burn patients had significantly higher BMI, procedure time, and postprocedure pain, relative to control subjects (p < 0.05, one-tailed testing). No one in either group had evidence of dispersive pad malattachment. Conclusions. Our results indicate that burn patients had higher BMI and longer procedure times compared to control subjects. These findings warrant further larger studies on this topic. PMID:27213077

  18. Prevention and Treatment of Lower Limb Deep Vein Thrombosis after Radiofrequency Catheter Ablation: Results of a Prospective active controlled Study

    PubMed Central

    Li, Lan; Zhang, Bao-jian; Zhang, Bao-ku; Ma, Jun; Liu, Xu-zheng; Jiang, Shu-bin

    2016-01-01

    We conducted a prospective, single-center, active controlled study from July 2013 to January 2015, in Chinese patients with rapid ventricular arrhythmia who had received radiofrequency catheter ablation (RFCA) treatment to determine formation of lower extremity deep vein thrombosis (LDVT) post RFCA procedure, and evaluated the effect of rivaroxaban on LDVT. Patients with asymptomatic pulmonary thromboembolism who had not received any other anticoagulant and had received no more than 36 hours of treatment with unfractionated heparin were included. Post RFCA procedure, patients received either rivaroxaban (10 mg/d for 14 days beginning 2–3 hours post-operation; n = 86) or aspirin (100 mg/d for 3 months beginning 2–3 hours post-operation; n = 90). The primary outcome was a composite of LDVT occurrence, change in diameter of femoral veins, and safety outcomes that were analyzed based on major or minor bleeding events. In addition, blood flow velocity was determined. No complete occlusive thrombus or bleeding events were reported with either of the group. The lower incidence rate of non-occluded thrombus in rivaroxaban (5.8%) compared to the aspirin group (16.7%) indicates rivaroxaban may be administered post-RFCA to prevent and treat femoral venous thrombosis in a secure and effective way with a faster inset of action than standard aspirin therapy. PMID:27329582

  19. Unintended Thermal Injuries from Radiofrequency Ablation: Organ Protection with an Angioplasty Balloon Catheter in an Animal Model

    PubMed Central

    Knuttinen, Martha-Grace; Van Ha, Thuong G.; Reilly, Christopher; Montag, Anthony; Straus, Christopher

    2014-01-01

    Objectives: The aim of this study was to investigate a novel approach of using a balloon catheter as a protective device to separate liver from the diaphragm or nearby bowel during radiofrequency ablation (RFA) of hepatic dome tumors in an animal model. Materials and Methods: All experimental procedures were approved by animal Institutional Review Board. Using a 3 cm RF needle electrode, 70 hepatic ablation zones were created using ultrasound in 7 pigs. 50 lesions were created using balloon interposition between liver and diaphragm; 20 lesions were created using the balloon device interposed posteriorly between liver and bowel. Additional 21 control lesions were performed. Animals were sacrificed immediately; diaphragm and bowel were then visually inspected and sectioned. Diaphragmatic and bowel injury was then classified according to the depth of thickness. Results: Control lesions caused full thickness injury, either to diaphragm or bowel. During ablation of lesions with balloon interposition, there was significantly less diaphragmatic injury, P < 0.001 and less bowel injury, P < 0.01. Conclusion: Using balloon interposition as a protective device has advantages over previous saline infusion or CO2 insufflation, providing a safe way to expand percutaneous RFA of liver tumors located on the undersurface of the diaphragm. In addition, this method may be used in protection of other organs adjacent to areas being ablated. PMID:24678433

  20. Force-Sensing Catheters During Pediatric Radiofrequency Ablation: The FEDERATION Study.

    PubMed

    Dalal, Aarti S; Nguyen, Hoang H; Bowman, Tammy; Van Hare, George F; Avari Silva, Jennifer N

    2017-05-17

    Based on data from studies of atrial fibrillation ablations, optimal parameters for the TactiCath (TC; St. Jude Medical, Inc) force-sensing ablation catheter are a contact force of 20 g and a force-time integral of 400 g·s for the creation of transmural lesions. We aimed to evaluate TC in pediatric and congenital heart disease patients undergoing ablation. Comprehensive chart and case reviews were performed from June 2015 to March 2016. Of the 102 patients undergoing electrophysiology study plus ablation, 58 (57%) underwent ablation initially with a force-sensing catheter. Patients had an average age of 14 (2.4-23) years and weight of 58 (18-195) kg with 15 patients having abnormal cardiac anatomy. Electrophysiology diagnoses for the +TC group included 30 accessory pathway-mediated tachycardia, 24 atrioventricular nodal reentrant tachycardia, and 7 other. Baseline generator settings included a power of 20 W, temperature of 40°, and 6 cc/min flow during lesion creation with 11 patients (19%) having alterations to parameters. Seventeen patients (30%) converted to an alternate ablation source. A total of 516 lesions were performed using the TC with a median contact force of 6 g, force-time integral of 149 g·s, and lesion size index of 3.3. Median-term follow-up demonstrated 5 (10%) recurrences with no acute or median-term complications. TactiCath can be effectively employed in the treatment of pediatric patients with congenital heart disease with lower forces than previously described in the atrial fibrillation literature. Patients with atrioventricular nodal reentrant tachycardia or atrioventricular reciprocating tachycardia may not require transmural lesions and the TC may provide surrogate markers for success during slow pathway ablation. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

  1. Visualizing intramyocardial steam formation with a radiofrequency ablation catheter incorporating near-field ultrasound.

    PubMed

    Wright, Matthew; Harks, Erik; Deladi, Szabolcs; Fokkenrood, Steven; Zuo, Fei; Van Dusschoten, Anneke; Kolen, Alexander F; Belt, Harm; Sacher, Frederic; Hocini, Mélèze; Haïssaguerre, Michel; Jaïs, Pierre

    2013-12-01

    Steam pops are a risk of irrigated RF ablation even when limiting power delivery. There is currently no way to predict gas formation during ablation. It would be useful to visualize intramyocardial gas formation prior to a steam pop occurring using near-field ultrasound integrated into a RF ablation catheter. In an in vivo open-chest ovine model (n = 9), 86 lesions were delivered to the epicardial surface of the ventricles. Energy was delivered for 15-60 seconds, to achieve lesions with and without steam pops, based on modeling data. The ultrasound image was compared to a digital audio recording from within the pericardium by a blinded observer. Of 86 lesions, 28 resulted in an audible steam pop. For lesions that resulted in a steam pop compared to those that did not (n = 58), the mean power delivered was 8.0 ± 1.8 W versus 6.7 ± 2.0 W, P = 0.006. A change in US contrast due to gas formation in the tissue occurred in all lesions that resulted in a steam pop. In 4 ablations, a similar change in US contrast was observed in the tissue and RF delivery was stopped; in these cases, no pop occurred. The mean depth of gas formation was 0.9 ± 0.8 mm, which correlated with maximal temperature predicted by modeling. Changes in US contrast occurred 7.6 ± 7.2 seconds before the impedance rise and 7.9 ± 6.2 seconds (0.1-17.0) before an audible pop. Integrated US in an RF ablation catheter is able to visualize gas formation intramyocardially several seconds prior to a steam pop occurring. This technology may help prevent complications arising from steam pops. © 2013 Wiley Periodicals, Inc.

  2. Catheter ablation.

    PubMed

    Fromer, M; Shenasa, M

    1991-02-01

    Catheter ablation is gaining increasing interest for the therapy of symptomatic, sustained arrhythmias of various origins. The scope of this review is to give an overview of the biophysical aspects and major characteristics of some of the most widely used energy sources in catheter ablation, e.g., the discharge of conventional defibrillators, modified defibrillators, laser light, and radiofrequency current application. Results from animal studies are considered to explain the basic mechanisms of catheter ablation. The recent achievements with the use of radiofrequency current to modify or ablate cardiac conduction properties are outlined in more detail.

  3. Catheter-Based Radiofrequency Renal Denervation: Location Effects on Renal Norepinephrine

    PubMed Central

    Zhang, Yongxing; Hata, Cary; Narciso, Irvin; Hall, Michael E.; Hall, John E.

    2015-01-01

    BACKGROUND Clinical studies indicate that blood pressure (BP)-lowering effects of radiofrequency (RF) renal denervation (RD) are sustained for up to 2 years, although a recent clinical trial failed to find a major effect compared to sham treatment. In most previous studies, the efficacy of RD has not been assessed. The current study determined whether RD in different regions of the renal artery causes different degrees of RD as assessed with renal norepinephrine (NE) levels. METHODS AND RESULTS Unilateral RD was performed on 14 pigs divided into 3 groups: RD near the ostium, in the main renal artery near the bifurcation, and in extrarenal branches of the renal artery. After 2 weeks post-RD, the pigs were euthanized, renal cortex tissue was collected for NE measurement, and renal arteries were prepared for histological analysis. Renal NE decreased by 12% with RD at the ostium, 45% with RD near the bifurcation in the main renal artery, and 74% when RD was performed in extrarenal artery branches. The number of renal nerves was greatest in extrarenal branches and in the main artery compared to the ostium and the average distance from the lumen was greatest for nerves at the ostium and least at the branches. CONCLUSIONS RF RD lowers renal NE more significantly when performed in branches of the renal artery closer to the kidney. Increased efficacy of RF RD in extrarenal arterial branches may be due to the greater number of nerves in close proximity to the artery lumen in the branches. PMID:25576624

  4. Idiopathic ventricular arrhythmias originating from the papillary muscles in the left ventricle: prevalence, electrocardiographic and electrophysiological characteristics, and results of the radiofrequency catheter ablation.

    PubMed

    Yamada, Takumi; Doppalapudi, Harish; McElderry, Hugh T; Okada, Taro; Murakami, Yoshimasa; Inden, Yasuya; Yoshida, Yukihiko; Kaneko, Shinji; Yoshida, Naoki; Murohara, Toyoaki; Epstein, Andrew E; Plumb, Vance J; Kay, G Neal

    2010-01-01

    Idiopathic ventricular arrhythmias (VAs) can originate from the left ventricular (LV) papillary muscles (PAMs). This study investigated the prevalence, electrocardiographic and electrophysiological characteristics, and results of catheter ablation of these VAs, and compared them with other LV VAs. We studied 71 patients with VAs originating from the LV anterolateral and posteroseptal regions among 159 patients undergoing successful catheter ablation of idiopathic LV VAs. PAM VAs were uncommon, rare in a sustained form, and more common from the posterior papillary muscle (PPM) than anterior papillary muscle (APM). A younger age was a good predictor for differentiating left posterior fascicular VAs from PPM VAs. There were several electrocardiographic features that accurately differentiated PAM and LV fascicular VAs from mitral annular VAs. However, an R/S ratio < or =1 in lead V6 in the LV anterolateral region and a QRS duration >160 ms in the LV posteroseptal region were the only reliable predictors for differentiating PAM VAs from LV fascicular VAs. A sharp ventricular prepotential was recorded at the successful ablation site during 42% of the PAM VAs. Radiofrequency current with an irrigated or conventional 8-mm tip ablation catheter was required to achieve a lasting ablation of the PAM VA origins whereas that with a nonirrigated 4-mm tip ablation catheter produced excellent results in LV fascicular and mitral annular VAs. There are differences in the electrocardiographic and electrophysiological features among VAs originating from these regions that are helpful for their diagnosis and effective catheter ablation.

  5. Predictors of sick sinus syndrome in patients after successful radiofrequency catheter ablation of atrial flutter.

    PubMed

    Song, Changho; Jin, Moo-Nyun; Lee, Jung-Hee; Kim, In-Soo; Uhm, Jae-Sun; Pak, Hui-Nam; Lee, Moon-Hyoung; Joung, Boyoung

    2015-01-01

    The identification of sick sinus syndrome (SSS) in patients with atrial flutter (AFL) is difficult before the termination of AFL. This study investigated the patient characteristics used in predicting a high risk of SSS after AFL ablation. Out of 339 consecutive patients who had undergone radiofrequency ablation for AFL from 1991 to 2012, 27 (8%) had SSS (SSS group). We compared the clinical characteristics of patients with and without SSS (n=312, no-SSS group). The SSS group was more likely to have a lower body mass index (SSS: 22.5±3.2; no-SSS: 24.0±3.0 kg/m²; p=0.02), a history of atrial septal defects (ASD; SSS: 19%; no-SSS: 6%; p=0.01), a history of coronary artery bypass graft surgery (CABG; SSS: 11%; no-SSS: 2%; p=0.002), and a longer flutter cycle length (CL; SSS: 262.3±39.2; no-SSS: 243.0±40; p=0.02) than the no-SSS group. In multivariate analysis, a history of ASD [odds ratio (OR) 3.7, 95% confidence interval (CI) 1.2-11.4, p=0.02] and CABG (7.1, 95% CI 1.5-32.8, p=0.01) as well as longer flutter CL (1.1, 95% CI 1.0-1.2, p=0.04) were independent risk factors for SSS. A history of ASD and CABG as well as longer flutter CL increased the risk of SSS after AFL ablation. While half of the patients with SSS after AFL ablation experienced transient SSS, heart failure was associated with irreversible SSS.

  6. Acute success and short-term follow-up of catheter ablation of isthmus-dependent atrial flutter; a comparison of 8 mm tip radiofrequency and cryothermy catheters

    PubMed Central

    Janse, P.; Alings, M.; Scholten, M. F.; Mekel, J. M.; Miltenburg, M.; Jessurun, E.; Jordaens, L.

    2008-01-01

    Objectives To compare the acute success and short-term follow-up of ablation of atrial flutter using 8 mm tip radiofrequency (RF) and cryocatheters. Methods Sixty-two patients with atrial flutter were randomized to RF or cryocatheter (cryo) ablation. Right atrial angiography was performed to assess the isthmus. End point was bidirectional isthmus block on multiple criteria. A pain score was used and the analgesics were recorded. Patients were followed for at least 3 months. Results The acute success rate for RF was 83% vs 69% for cryo (NS). Procedure times were similar (mean 144 ± 48 min for RF, vs 158 ± 49 min for cryo). More applications were given with RF than with cryo (26 ± 17 vs. 18 ± 10, p < 0.05). Fluoroscopy time was longer with RF (29 ± 15 vs. 19 ± 12 min, p < 0.02). Peak CK, CK-MB and CK-MB mass were higher, also after 24 h in the cryo group. Troponin T did not differ. Repeated transient block during application (usually with cryoablation) seemed to predict failure. Cryothermy required significantly less analgesia (p < 0.01), and no use of long sheaths (p < 0.005). The isthmus tended to be longer in the failed procedures (p = 0.117). This was similar for both groups, as was the distribution of anatomic variations. Recurrences and complaints in the successful patients were similar for both groups, with a very low recurrence of atrial flutter after initial success. Conclusions In this randomized study there was no statistical difference but a trend to less favorable outcome with 8 mm tip cryocatheters compared to RF catheters for atrial flutter ablation. Cryoablation was associated with less discomfort, fewer applications, shorter fluoroscopy times and similar procedure times. The recurrence rate was very low. Cryotherapy can be considered for atrial flutter ablation under certain circumstances especially when it has been used previously in the same patient, such as in an AF ablation. PMID:18363087

  7. The optimal range of international normalized ratio for radiofrequency catheter ablation of atrial fibrillation during therapeutic anticoagulation with warfarin.

    PubMed

    Kim, Jin-Seok; Jongnarangsin, Krit; Latchamsetty, Rakesh; Chugh, Aman; Ghanbari, Hamid; Crawford, Thomas; Yokokawa, Miki; Good, Eric; Bogun, Frank; Pelosi, Frank; Morady, Fred; Oral, Hakan

    2013-04-01

    Uninterrupted anticoagulation with warfarin during radiofrequency catheter ablation (RFA) of atrial fibrillation is associated with a lower risk of periprocedural complications than when warfarin is temporarily discontinued. However, the optimal international normalized ratio (INR) levels during RFA have not been defined. In this retrospective analysis, RFA was performed in 1133 consecutive patients (mean age, 61±10 years) with paroxysmal (550) or persistent atrial fibrillation (583). Patients were grouped based on the INR on the day of RFA. There was a quadratic relationship between the INR and bleeding and vascular complications (P<0.001). Complications were less prevalent when INR was ≥2.0 and ≤3.0 (5% [31/572]) than when INR was <2.0 (10% [49/485]; P=0.004) and >3.0 (12% [9/76]; P=0.03). The prevalence of pericardial tamponade (1%) was similar at all INRs. From the quadratic model, the optimal range of INR was calculated as 2.1 to 2.5. INRs<2.0 and >3.0 were associated with a >2-fold increase in complications, with a further steep rise beyond an INR>3.5. Concomitant clopidogrel use was associated with a significant increase in complications at all INRs (odds ratio=3.1; ±95% confidence interval, 1.4-7.4). Unfractionated heparin requirements to maintain a therapeutic activated clotting time during RFA was reduced by 50% in patients with an INR>2.0. The optimal INR range during uninterrupted periprocedural anticoagulation using warfarin is narrow. Therefore, INR levels should be carefully monitored in preparation for RFA of atrial fibrillation.

  8. Prediction of very late arrhythmia recurrence after radiofrequency catheter ablation of atrial fibrillation: The MB-LATER clinical score.

    PubMed

    Mujović, Nebojša; Marinković, Milan; Marković, Nebojša; Shantsila, Alena; Lip, Gregory Y H; Potpara, Tatjana S

    2017-01-20

    Reliable prediction of very late recurrence of atrial fibrillation (VLRAF) occuring >12 months after catheter ablation (CA) in apparently "cured" patients could optimize long-term follow-up and modify decision-making regarding the discontinuation of oral anticoagulant therapy. In a single-centre cohort of consecutive patients post radiofrequency AFCA, we retrospectively derived a novel score for VLRAF prediction. Of 133 consecutive post AFCA patients (mean age 56.9 ± 11.8 years, 63.9% male, 69.2% with paroxysmal AF) who were arrhythmia-free at 12 months (excluding 3-month "blanking period"), 20 patients expirienced a VLRAF during a 29.1 ± 10.1-month follow-up, with a 3-year cumulative VLRAF rate of 31.1%. The MB-LATER score (Male, Bundle brunch block, Left atrium ≥47 mm, Type of AF [paroxysmal, persistent or long-standing persistent], and ER-AF = early recurrent AF), had better predictive ability for VLRAF (AUC 0.782) than the APPLE, ALARMc, BASE-AF2, CHADS2, CHA2DS2VASc or HATCH score (AUC 0.716, 0.671, 0.648, 0.552, 0.519 and 0.583, respectively), resulted in an improved net reclassification index (NRI) of 48.6-95.1% and better identified patients with subsequent VLRAF using decision-curve analysis (DCA). The MB-LATER score provides a readily available VLRAF risk assessment, and performs better than other scores. Validation of the MB-LATER score in other cohorts is underway.

  9. Prediction of very late arrhythmia recurrence after radiofrequency catheter ablation of atrial fibrillation: The MB-LATER clinical score

    PubMed Central

    Mujović, Nebojša; Marinković, Milan; Marković, Nebojša; Shantsila, Alena; Lip, Gregory Y. H.; Potpara, Tatjana S.

    2017-01-01

    Reliable prediction of very late recurrence of atrial fibrillation (VLRAF) occuring >12 months after catheter ablation (CA) in apparently “cured” patients could optimize long-term follow-up and modify decision-making regarding the discontinuation of oral anticoagulant therapy. In a single-centre cohort of consecutive patients post radiofrequency AFCA, we retrospectively derived a novel score for VLRAF prediction. Of 133 consecutive post AFCA patients (mean age 56.9 ± 11.8 years, 63.9% male, 69.2% with paroxysmal AF) who were arrhythmia-free at 12 months (excluding 3-month “blanking period”), 20 patients expirienced a VLRAF during a 29.1 ± 10.1-month follow-up, with a 3-year cumulative VLRAF rate of 31.1%. The MB-LATER score (Male, Bundle brunch block, Left atrium ≥47 mm, Type of AF [paroxysmal, persistent or long-standing persistent], and ER-AF = early recurrent AF), had better predictive ability for VLRAF (AUC 0.782) than the APPLE, ALARMc, BASE-AF2, CHADS2, CHA2DS2VASc or HATCH score (AUC 0.716, 0.671, 0.648, 0.552, 0.519 and 0.583, respectively), resulted in an improved net reclassification index (NRI) of 48.6–95.1% and better identified patients with subsequent VLRAF using decision-curve analysis (DCA). The MB-LATER score provides a readily available VLRAF risk assessment, and performs better than other scores. Validation of the MB-LATER score in other cohorts is underway. PMID:28106147

  10. Efficacy and Safety of Radiofrequency Catheter Ablation of Tachyarrhythmias in 123 Children Under 3 Years of Age.

    PubMed

    Jiang, H E; Li, Xiao-Mei; Li, Yan-Hui; Zhang, Yan; Liu, Hai-Ju

    2016-08-01

    The risk-benefit ratio of radiofrequency catheter ablation (RFCA) in infants and toddlers remains controversial. Experience with RFCA in these patients is limited. This work is intended to describe the efficacy and safety of RFCA in children under 3 years of age with tachycardia complicated by drug resistance, drug intolerance, or tachycardia-induced cardiomyopathy. We retrospectively reviewed data from 123 consecutive children under 3 years of age (mean, 2.3 ± 0.8 years; weight, 13.6 ± 2.8 kg) with tachycardia complicated by drug resistance, drug intolerance, or tachycardia-induced cardiomyopathy; the children underwent an electrophysiology study between 1994 and 2014 at our center. Fifteen children had congenital heart disease, and 27 children were under 1 year of age. Among the 109 children who underwent RFCA, acute success rate (no inducible arrhythmia before procedure completion), 2-year rate of symptomatic tachyarrhythmia recurrence, and complication rate were assessed. Among the 123 children studied, 76.4% had atrioventricular reentrant tachycardia, 5.7% had atrioventricular nodal reentrant tachycardia, 2.4% had focal atrial tachycardia, 6.5% had atrial flutter, and 4.1% had idiopathic left ventricular tachycardia. For RFCA, the acute success rate was 94.5%, and the 2-year recurrence rate was 6.8%, without any major complications. RFCA appears to be an effective and safe therapeutic option in selected small children with tachycardia resistant to conventional medical management, tachycardia complicated by drug intolerance, or tachycardia-induced cardiomyopathy. © 2016 Wiley Periodicals, Inc.

  11. Safety and Efficacy of Switching Anticoagulation to Aspirin Three Months after Successful Radiofrequency Catheter Ablation of Atrial Fibrillation

    PubMed Central

    Uhm, Jae-Sun; Won, Hoyoun; Joung, Boyoung; Nam, Gi-Byoung; Choi, Kee-Joon; Lee, Moon-Hyoung; Kim, You-Ho

    2014-01-01

    Purpose Although current guidelines recommend continuing the same antithrombotic strategy regardless of rhythm control after radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF), anticoagulation has a risk of major bleeding. We evaluated the safety of switching warfarin to aspirin in patients with successful AF ablation. Materials and Methods Among 721 patients who underwent RFCA of AF, 608 patients (age, 57.3±10.9 years; 77.0% male, 75.5% paroxysmal AF) who had no evidence of AF recurrence at 3 months post-RFCA were included. We compared the thromboembolic and hemorrhagic events in patients for whom warfarin was switched to aspirin (ASA group; n=296) and patients who were kept on warfarin therapy (W group; n=312). Results There were no significant differences in CHA2DS2-VASc or HAS-BLED scores between the groups. In 30 patients in the ASA group and 37 patients in W group, AF recurred and warfarin was restarted or maintained during the 18.0±12.2 months of follow-up. There were no significant differences in thromboembolic (0.3% vs. 1.0%, p=0.342) and major bleeding incidences (0.7% vs. 0.6%, p=0.958) between ASA and W groups during the follow-up period. In the 259 patients with a CHA2DS2-VASc score ≥2, there were no significant differences in thromboembolism (0.8% and 2.2%, p=0.380) or major bleeding incidences (0.8% and 1.4%, p=0.640) between ASA and W groups. Conclusion Switching warfarin to aspirin 3 months after successful RFCA of AF could be as safe and efficacious as long-term anticoagulation even in patients with CHA2DS2-VASc score ≥2. However, strict rhythm monitoring cannot be overemphasized. PMID:25048480

  12. The Role of Intravenous Dopamine on Hemodynamic Support during Radiofrequency Catheter Ablation of Poorly Tolerated Idiopathic Ventricular Tachycardia

    PubMed Central

    Ahn, Jinhee; Kim, Dong-Hyeok; Roh, Seung-Young; Lee, Kwang No; Lee, Dae-In; Shim, Jaemin; Choi, Jong-Il

    2017-01-01

    Background and Objectives Hemodynamically unstable idiopathic ventricular tachycardias (VTs) are a challenge for activation or entrainment mapping technique. Mechanical circulatory support is an option, but is not always readily available. In this study, we investigated the safety and efficacy of hemodynamic support using intravenous (IV) dopamine solely during radiofrequency catheter ablation (RFCA) of hemodynamically unstable VT. Subjects and Methods Seven out of 86 patients with hemodynamically unstable idiopathic VT underwent de novo RFCA using dopamine in our single center. They were included in the study and reviewed retrospectively to investigate the procedural characteristics and outcomes. Results All patients were male, and the mean age was 50.7±5.3 years. One patient had implantable cardioverter-defibrillator for the secondary prevention. No evidence of myocardial ischemia was found in all patients. During the procedure, the mean blood pressure during VT without dopamine was 52.3±4.1 mmHg and increased to 82.6±3.8 mmHg after administering dopamine (Δ28.8±3.2 mmHg; total average dopamine dosage was 1266.1±389.6 mcg/kg). In all patients, activation mapping was safely applied, and VTs were terminated during energy delivery. Non-inducibility of clinical VT was achieved in all cases. There was no evidence of deterioration due to hypoperfusion during the peri-procedural period. No recurrence of ventricular tachyarrhythmias was observed in any of the patients, during a median follow-up of 23.0±6.1 months. Conclusion Hemodynamic support using IV dopamine during RFCA of hemodynamically unstable idiopathic VT facilitated detailed mapping to guide successful ablation. PMID:28154593

  13. [Radiofrequency catheter ablation for ventricular premature beats of left coronary cusp under the guidance of 3-dimensional mapping system].

    PubMed

    Wang, Hong; Hong, Lang; Zhou, Yuan-feng; Lai, Heng-li; Chen, Zai-hua; Qiu, Yun

    2012-04-10

    To explore the efficacy and safety of radiofrequency catheter ablation (RCA) for ventricular premature beats originating from left coronary sinus under the guidance of 3-dimensional mapping system (CARTO). A total of 15 patients with premature ventricular contractions (PVCs) originating from left coronary sinus underwent CARTO-guided RCA. Anatomical structures were constructed and three-dimension (3D) electrical activation sequence was plotted for left ventricle and aortic sinus. The distance of earliest activation point of PVCs and origin of left coronary artery were surveyed after left coronary arteriography. The electrocardiogram (ECG) results showed that R-wave was upward in leads II, III and avF, QRS waves in lead I was mainly of rS, rs and rsr types, QS type in lead avL, RS, Rs and rS type in lead V(1), RS type in lead V(3) and absence of S wave in lead V(5)/V(6). Intraoperative mapping detected the earliest activation point on the posterior-inferior origin of left coronary artery (LMCA) ostium (n = 7), on the anterio-inferior of LMCA ostium (n = 3) and on the inferior of LMCA ostium (n = 5). The earliest activation point (local activation time) was shorter 86 - 120 ms than surface electrocardiogram QRS wave, discharge melting on the earliest activation point and nearby succeeded. PVCs disappeared, PVCs failed to be induced under similar preoperative conditions (aleudrin intravenous) and no complication occurred intraoperatively and postoperatively. The CARTO-guided RCA is a safe and effective in the treatment of PVCs originating from left coronary sinus.

  14. Pulmonary vein reconnection following catheter ablation of atrial fibrillation using the second-generation cryoballoon versus open-irrigated radiofrequency: results of a multicenter analysis.

    PubMed

    Aryana, Arash; Singh, Sheldon M; Mugnai, Giacomo; de Asmundis, Carlo; Kowalski, Marcin; Pujara, Deep K; Cohen, Andrew I; Singh, Steve K; Fuenzalida, Charles E; Prager, Nelson; Bowers, Mark R; O'Neill, Padraig Gearoid; Brugada, Pedro; d'Avila, André; Chierchia, Gian-Battista

    2016-12-01

    Catheter ablation of atrial fibrillation (CAAF) using the cryoballoon has emerged as an alternate strategy to point-by-point radiofrequency. However, there is little comparative data on long-term durability of pulmonary vein (PV) isolation comparing these two modalities. In this multicenter, retrospective analysis, the incidences/patterns of late PV reconnection following an index CAAF using the second-generation cryoballoon versus open-irrigated, non-force-sensing radiofrequency were examined. Of the 2002 patients who underwent a first-time CAAF, 186/1126 patients (16.5 %) ablated using cryoballoon and 174/876 patients (19.9 %) with non-contact force-guided radiofrequency required a repeat procedure at 11 ± 5 months. During follow-up, the incidence of atrial flutters/tachycardias was lower (19.9 vs. 32.8 %; p = 0.005) and fewer patients exhibited PV reconnection (47.3 vs. 60.9 %; p = 0.007) with cryoballoon versus radiofrequency. Additionally, fewer PVs had reconnected with cryoballoon versus radiofrequency (18.8 vs. 34.6 %; p < 0.001). With cryoballoon, the right inferior (p < 0.001) and left common (p = 0.039) PVs were more likely to exhibit late reconnection, versus the left superior PV with radiofrequency (p = 0.012). However, when comparing the two strategies, the left common PV was more likely to exhibit reconnection with cryoballoon, whereas all other PVs with the exception of the right inferior PV demonstrated a lower reconnection rate with cryoballoon versus radiofrequency. Lastly, in a logistic regression multivariate analysis, cryoballoon ablation and PV ablation time emerged as significant predictors of durable PV isolation at repeat procedure. In this large multicenter, retrospective analysis, CAAF using the second-generation cryoballoon was associated with improved durability of PV isolation compared to open-irrigated, non-force-sensing radiofrequency.

  15. Does diffuse irrigation result in improved radiofrequency catheter ablation? A prospective randomized study of right atrial typical flutter ablation.

    PubMed

    Ramoul, Khaled; Wright, Matthew; Sohal, Manav; Shah, Ashok; Castro-Rodriguez, Jose; Verbeet, Thierry; Knecht, Sébastien

    2015-02-01

    Recent developments of open irrigated catheters have sought to create uniform cooling of the entire ablating electrode. The aim of this randomized study was to assess whether the diffuse irrigation of the Coolflex(®) (CF) catheter results in improved short-term procedural benefits in patients undergoing ablation of right atrial typical flutter. Sixty consecutive patients (age 62 ± 13) with typical atrial flutter were prospectively randomized to ablation of the cavotricuspid isthmus (CTI) using either a standard 3.5 mm tip ablation catheter with six distal irrigation channels (6C) (30 patients) or a 4 mm tip fully irrigated ablation catheter (CF) (30 patients). There were no significant differences seen between procedures performed with the diffusely irrigated CF catheter and the standard six-channel irrigated-tip catheter. This concerned the total procedural duration RF duration, fluoroscopic duration, the total amount of irrigation fluid, and the occurrence of steam pop. The use of a diffuse irrigation at the ablation catheter tip does neither facilitate lesion formation nor reduce the amount of irrigation during RF ablation for typical right atrial flutter using recommended flow and power settings. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

  16. Comparison of antiarrhythmic drug therapy and radiofrequency catheter ablation in patients with paroxysmal atrial fibrillation: a randomized controlled trial.

    PubMed

    Wilber, David J; Pappone, Carlo; Neuzil, Petr; De Paola, Angelo; Marchlinski, Frank; Natale, Andrea; Macle, Laurent; Daoud, Emile G; Calkins, Hugh; Hall, Burr; Reddy, Vivek; Augello, Giuseppe; Reynolds, Matthew R; Vinekar, Chandan; Liu, Christine Y; Berry, Scott M; Berry, Donald A

    2010-01-27

    Antiarrhythmic drugs are commonly used for prevention of recurrent atrial fibrillation (AF) despite inconsistent efficacy and frequent adverse effects. Catheter ablation has been proposed as an alternative treatment for paroxysmal AF. To determine the efficacy of catheter ablation compared with antiarrhythmic drug therapy (ADT) in treating symptomatic paroxysmal AF. A prospective, multicenter, randomized (2:1), unblinded, Bayesian-designed study conducted at 19 hospitals of 167 patients who did not respond to at least 1 antiarrhythmic drug and who experienced at least 3 AF episodes within 6 months before randomization. Enrollment occurred between October 25, 2004, and October 11, 2007, with the last follow-up on January 19, 2009. Catheter ablation (n = 106) or ADT (n = 61), with assessment for effectiveness in a comparable 9-month follow-up period. Time to protocol-defined treatment failure. The proportion of patients who experienced major treatment-related adverse events within 30 days of catheter ablation or ADT was also reported. At the end of the 9-month effectiveness evaluation period, 66% of patients in the catheter ablation group remained free from protocol-defined treatment failure compared with 16% of patients treated with ADT. The hazard ratio of catheter ablation to ADT was 0.30 (95% confidence interval, 0.19-0.47; P < .001). Major 30-day treatment-related adverse events occurred in 5 of 57 patients (8.8%) treated with ADT and 5 of 103 patients (4.9%) treated with catheter ablation. Mean quality of life scores improved significantly in patients treated by catheter ablation compared with ADT at 3 months; improvement was maintained during the course of the study. Among patients with paroxysmal AF who had not responded to at least 1 antiarrhythmic drug, the use of catheter ablation compared with ADT resulted in a longer time to treatment failure during the 9-month follow-up period. clinicaltrials.gov Identifier: NCT00116428.

  17. Successful radiofrequency ablation of atrial tachycardias in surgically repaired Ebstein's anomaly using the Carto XP system and the QwikStar catheter.

    PubMed

    Drago, Fabrizio; Brancaccio, Gianluca; Grutter, Giorgia; De Santis, Antonella; Fazio, Giovanni; Silvetti, Massimo Stefano

    2007-06-01

    We describe the case of a child with three different atrial tachyarrhythmias originating from the right atrium, in whom a limited modified maze procedure was performed during surgical repair of an Ebstein's anomaly. Successful radiofrequency transcatheter ablation of all atrial tachyarrhythmias, one re-entrant and two focal, was obtained using the Carto XP EP three-dimensional navigation and ablation system, the new QwikMap software technology and the new mapping/ablation QwikStar multipolar catheter. No conventional mapping was used in addition to the three-dimensional system. Total procedural time was about 3 h and fluoroscopy time was 40 min. There were neither recurrences of the tachycardias nor complications during the follow-up (15 months).

  18. Impact of Additional Transthoracic Electrical Cardioversion on Cardiac Function and Atrial Fibrillation Recurrence in Patients with Persistent Atrial Fibrillation Who Underwent Radiofrequency Catheter Ablation.

    PubMed

    Wang, Deguo; Zhang, Fengxiang; Wang, Ancai

    2016-01-01

    Backgrounds and Objective. During the procession of radiofrequency catheter ablation (RFCA) in persistent atrial fibrillation (AF), transthoracic electrical cardioversion (ECV) is required to terminate AF. The purpose of this study was to determine the impact of additional ECV on cardiac function and recurrence of AF. Methods and Results. Persistent AF patients received extensive encircling pulmonary vein isolation (PVI) and additional line ablation. Patients were divided into two groups based on whether they need transthoracic electrical cardioversion to terminate AF: electrical cardioversion (ECV group) and nonelectrical cardioversion (NECV group). Among 111 subjects, 35 patients were returned to sinus rhythm after ablation by ECV (ECV group) and 76 patients had AF termination after the ablation processions (NECV group). During the 12-month follow-ups, the recurrence ratio of patients was comparable in ECV group (15/35) and NECV group (34/76) (44.14% versus 44.74%, P = 0.853). Although left atrial diameters (LAD) decreased significantly in both groups, there were no significant differences in LAD and left ventricular cardiac function between ECV group and NECV group. Conclusions. This study revealed that ECV has no significant impact on the maintenance of SR and the recovery of cardiac function. Therefore, ECV could be applied safely to recover SR during the procedure of catheter ablation of persistent atrial fibrillation.

  19. Induction of ventricular tachycardia during radiofrequency ablation via pulmonary vein ablation catheter in a patient with an implanted pacemaker.

    PubMed

    Hammwöhner, Matthias; Stachowitz, Jörg; Willich, Tobias; Goette, Andreas

    2012-02-01

    Pulmonary vein isolation in a dual-chamber pacemaker patient using the pulmonary vein ablation catheter (PVAC) system resulted in perpetual induction of ventricular tachycardia (VT) during radio frequency energy application. Induction of VT was abolished by programming the PVAC-system to a pure bipolar ablation mode. Patients with implanted devices should be closely monitored when using the PVAC system in unipolar modes.

  20. Minimal Use of Fluoroscopy to Reduce Fetal Radiation Exposure during Radiofrequency Catheter Ablation of Maternal Supraventricular Tachycardia

    PubMed Central

    Raman, Ajay Sundara; Hariharan, Ramesh

    2015-01-01

    Electrophysiologic procedures in the young engender concern about the potential long-term effects of radiation exposure. This concern is manifold if such procedures are contemplated during pregnancy. Catheter ablations in pregnancy are indicated only in the presence of an unstable tachycardia that cannot be controlled by antiarrhythmic agents. This report describes the case of an 18-year-old pregnant woman and our stratagem to minimize irradiation of the mother and the fetus. PMID:25873828

  1. Prevalence, risk, and benefits of radiofrequency catheter ablation at the aortic cusp for the treatment of mid- to anteroseptal supra-ventricular tachyarrhythmias.

    PubMed

    Park, Junbeom; Wi, Jin; Joung, Boyoung; Lee, Moon Hyoung; Kim, Young-Hoon; Hwang, Chun; Pak, Hui-Nam

    2013-08-10

    Some outflow tract ventricular tachycardias (VTs) are known to be successfully ablated from the aortic cusp (AC). However, radiofrequency catheter ablation (RFCA) at the AC for the treatment of supraventricular tachyarrhythmia (SVT) has limited experience. We performed RFCA at the AC in 19 patients (male 64.7%, 46.9 ± 21.9 years old) with mid- to anteroseptal SVTs (12 atrial tachycardias [AT], 7 atrioventricular reciprocating tachycardia [AVRT]), and analyzed the prevalence, electrophysiologic findings, clinical outcome, and compilation risk. 1. Among 113 patients with AT, 13 patients had mid- to anteroseptal AT and 12 patients (8.8%, 53.4 ± 19.8 years old, 58.3% female) underwent successful ablation from the non-coronary cusp (NCC; n=10), right CC (RCC; n=1) or left CC (LCC; n=1) without complication (3.1 ± 2.3 times RF delivery, 6.15 ± 3.08 s for termination). During 19.7 ± 9.8 months of follow-up, AT recurred in a patient with multiple foci. 2. Among 580 patients with AVRT, 27 patients had a mid- to anteroseptal bypass tract (4.7%), and 7 of them (1.1%, 2 pre-excitation syndrome, 5 concealed bypass tract) were successfully ablated at the NCC (n=2) or RCC (n=5) (7.0 ± 7.1 times RF delivery, 9.1 ± 4.4s for termination). Among 5 patients with AVRT successfully ablated at the RCC, one patient developed complete heart block 48 h after procedure, and 2 patients recurred AVRT or delta-wave in ECG during 13.9 ± 11.7 month follow-up. Catheter ablation within the AC is an effective procedure to eliminate mid- to anteroseptal SVTs. However, RFCA on RCC requires a caution for heart block in our limited experience. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  2. Long-term follow-up after catheter ablation for atrioventricular nodal reentrant tachycardia: a comparison of cryothermal and radiofrequency energy in a large series of patients

    PubMed Central

    Knops, Paul; Janse, Petter; Kimman, Geert; Van Belle, Yves; Szili-Torok, Tamas; Jordaens, Luc

    2010-01-01

    Background Radiofrequency (RF) catheter ablation for atrioventricular nodal reentrant tachycardia (AVNRT) is highly successful but carries a risk for inadvertent atrioventricular block. Cryoablation (cryo) has the potential to assess the safety of a site before the energy is applied. Purpose The aim of this study was to evaluate the long-term efficacy and safety of cryothermal ablation in a large series of patients and compare it to RF. Methods All consecutive routinely performed AVNRT ablations from our centre between 1999 and 2007 were retrospectively analysed. Results In total, 274 patients were elegible: 150 cryoablations and 124 RF. Overall procedural success was 96% (262/274), and equal in both groups, but nine patients were crossed to another arm. Mean fluoroscopy time was longer in the group treated with RF (27 ± 22 min vs. cryo 19 ± 15 min; p = 0.002). Mean procedure time was not different (RF 138 ± 71 min vs. cryo 146 ± 60 min). A permanent pacemaker was necessary in two RF patients. The questionnaire revealed a high incidence of late arrhythmia related symptoms (48%), similar in both groups, with improved perceived quality of life. The number of redo procedures for AVNRT over 4.3 ± 2.5-years follow-up was not statistically different (11% after cryo and 5% after RF). Conclusions Our data confirm that cryo and RF ablation with 4-mm tip catheters for AVNRT are equally effective, even after long-term follow-up. PMID:21153914

  3. Long-term results of radiofrequency catheter ablation in non-ischemic sustained ventricular tachycardia with underlying heart disease. Nonuniform arrhythmogenic substrate and mode of ablation.

    PubMed

    Chinushi, M; Aizawa, Y; Ohhira, K; Abe, A; Shibata, A

    1996-03-01

    This study examined 12 VTs in 8 patients who underwent radiofrequency (RF) catheter ablation for ventricular tachycardia (VT) associated with non-ischemic underlying heart diseases, and who were followed-up for more than 24 months after ablation. The site of VT origin was determined to be within a narrow site (within 1.0 x 1.0 cm) in 5 VTs (4 patients), but VT originated from a wide origin (more than 1.0 x 1.0 cm) in the other 5 VTs (3 patients). The remaining patient had two macroreentrant VTs revolving around an anatomical obstacle in both the clockwise and counterclockwise directions. Two of 5 VTs originating from a narrow site were successfully ablated by 2-3 RF applications. In VT associated with a wide origin, two perpendicular linear RF lesions with 6.0 +/- 1.8 RF applications were required to ablate the VT. Eight of the 12 VTs (66.7%) were finally ablated by RF current (30-50 watts), and they did not recur during the follow-up period of 31.2 +/- 6.5 months. An excellent long-term outcome is expected, even in VT associated with non-ischemic underlying heart disease, if VT is successfully treated by RF ablation.

  4. Characterization of Pulmonary Vein Dimensions Using High-Definition 64-Slice Computed Tomography prior to Radiofrequency Catheter Ablation for Atrial Fibrillation.

    PubMed

    Gebhard, Catherine; Krasniqi, Nazmi; Stähli, Barbara E; Klaeser, Bernd; Fuchs, Tobias A; Ghadri, Jelena R; Haegeli, Laurent; Lüscher, Thomas F; Kaufmann, Philipp A; Duru, Firat

    2014-01-01

    Background. Contrast-enhanced computed tomography is commonly acquired before radiofrequency catheter ablation (RFCA) for atrial fibrillation (AFib) to guide the procedure. We analyzed pulmonary vein (PV) ostial diameter and volumes on a high-definition 64-slice CT (HDCT) scanner in patients with AFib prior to RFCA. Methods and Results. This retrospective study included 50 patients (mean age 60.2 ± 11.4 years, 30 males) undergoing cardiac HDCT scanning before RFCA for drug refractory AFib and 50 age-, BMI-, and sex-matched controls with normal sinus rhythm undergoing HDCT. PV ostial diameter and volume were measured and calculated using a semiautomatic calliper tool. Total ostial PV volume was significantly increased in patients with AFib as compared to controls (P < 0.005). Similarly, total ostial PV diameter was significantly increased in AFib compared to controls (P < 0.001). In AFib, the largest PV volume and diameters were measured in right superior PV (P < 0.05 versus controls). The difference in PV volume between patients and controls was most pronounced in right superior PVs (P = 0.015). Right middle PVs were found more often in patients with AFib (16/50; 32%) than in normal subjects (7/50; 14%). Conclusion. Enlargement of PV ostial area and enlargement of volume are frequent findings in patients with drug refractory AFib. These parameters may add to the risk stratification for AFib recurrence following RFCA.

  5. Multi-detector row CT of the left atrium and pulmonary veins before radio-frequency catheter ablation for atrial fibrillation.

    PubMed

    Lacomis, Joan M; Wigginton, William; Fuhrman, Carl; Schwartzman, David; Armfield, Derek R; Pealer, Karen M

    2003-10-01

    Radio-frequency catheter ablation (RFCA) of the distal pulmonary veins and posterior left atrium is increasingly being used to treat recurrent or refractory atrial fibrillation that resists pharmacologic therapy or cardioversion. Successful RFCA of atrial fibrillation requires resolution of abnormal rhythms while minimizing complications and can be achieved with precise, preprocedural, three-dimensional (3D) anatomic delineation of the target, the atriopulmonary venous junction. Three-dimensional multi-detector row computed tomography (CT) of the pulmonary veins and left atrium provides the necessary anatomic information for successful RFCA, including (a) the number, location, and angulation of pulmonary veins and their ostial branches unobscured by adjacent cardiac and vascular anatomy, and (b) left atrial volume. The 3D multi-detector row CT scanning and postprocessing techniques used for pre-RFCA planning are straightforward. Radiologists must not only understand these techniques but must also be familiar with atrial fibrillation and the technical considerations and complications associated with RFCA of this condition. In addition, radiologists must be familiar with anatomic variants of the left atrium and distal pulmonary veins and understand the importance of these variants to the referring cardiac interventional electrophysiologist. Copyright RSNA, 2003

  6. Prognostic value of total atrial conduction time estimated with tissue Doppler imaging to predict the recurrence of atrial fibrillation after radiofrequency catheter ablation.

    PubMed

    den Uijl, Dennis W; Gawrysiak, Marcin; Tops, Laurens F; Trines, Serge A; Zeppenfeld, Katja; Schalij, Martin J; Bax, Jeroen J; Delgado, Victoria

    2011-11-01

    Total atrial activation time has been identified as an independent predictor of new-onset atrial fibrillation (AF). Echocardiographic assessment of PA-TDI duration provides an estimation of total atrial conduction time. The aim of this study was to investigate the prognostic value of total atrial conduction time to predict AF recurrence after radiofrequency catheter ablation (RFCA). In 213 patients undergoing RFCA for symptomatic drug-refractory paroxysmal AF, the total atrial conduction time was estimated by measuring the time delay between the onset of the P-wave in lead II of the surface electrocardiogram and the peak A'-wave on the tissue Doppler tracing of the left atrial (LA) lateral wall (PA-TDI duration). After RFCA, all patients were evaluated on a systematic basis at the outpatient clinic. After a mean follow-up of 13 ± 3 months, 74 patients (35%) had recurrent AF whereas 139 patients (65%) maintained sinus rhythm. Left atrial maximum volume index and PA-TDI duration were identified as independent predictors of AF recurrence after RFCA. However, receiver operator characteristics curve analyses demonstrated that PA-TDI duration had a superior accuracy to predict AF recurrence compared with LA maximum volume index (area under the curve 0.765 vs. 0.561, respectively). Assessment of total atrial conduction time using tissue Doppler imaging can be used to predict AF recurrence after RFCA.

  7. Electrocardiogram features of premature ventricular contractions/ventricular tachycardia originating from the left ventricular outflow tract and the treatment outcome of radiofrequency catheter ablation

    PubMed Central

    2012-01-01

    Background Radiofrequency catheter ablation (RFCA) has been used for the ablation of premature ventricular contractions (PVCs) or ventricular tachycardia (VT). To date, the mapping and catheter ablation of the arrhythmias originating from the left ventricular outflow tract (LVOT) has not been specified. This study investigates the electrocardiogram (ECG) feature of PVCs or VT originating from the LVOT. Moreover, the treatment outcome of RFCA is analyzed. Methods Mapping and ablation were performed on the supravalvular or subvalvular aorta in 52 cases with PVCs/VT originating from the LVOT. The data were compared with those from 104 patients with PVCs/VT originating from the right ventricular outflow tract (RVOT). A differential procedure was prepared based on the comparison of the ECG features of PVCs/VT originating from the RVOT, LVOT, and their different parts. Results Among 52 cases with PVCs originating from the LVOT, 47 were successfully treated by RFCA, with a success rate of 90.38%. Several differences among the 12-lead ECG features were observed from the RVOT and LVOT in the left and right coronary sinus groups, as well as under the left coronary sinus group (left fibrous trigone): (1) If the precordial leads transition 0 are considered as the diagnostic parameters of PVCs/VT originating from the LVOT, then the sensitivity, specificity, as well as positive and negative predictive values are 94.12%, 93.00%, 87.27%, and 96.88%, respectively; (2) The analysis of different subgroups of the LVOT are as follows: (a) A mainly positive wave of r or m pattern was recorded in the lead I in 72.73% of patients in the right coronary sinus group, versus 12.90% of patients in the left coronary sinus group, and 0% in the under left coronary sinus group. (b) All patients in the right coronary sinus group presented waves of RII>RIII and QSaVR>QSaVL, whereas most patients in the other two groups showed waves of RIII>RII and

  8. Relationship between catheter contact force and radiofrequency lesion size and incidence of steam pop in the beating canine heart: electrogram amplitude, impedance, and electrode temperature are poor predictors of electrode-tissue contact force and lesion size.

    PubMed

    Ikeda, Atsushi; Nakagawa, Hiroshi; Lambert, Hendrik; Shah, Dipen C; Fonck, Edouard; Yulzari, Aude; Sharma, Tushar; Pitha, Jan V; Lazzara, Ralph; Jackman, Warren M

    2014-12-01

    Electrode-tissue contact force (CF) is believed to be a major factor in radiofrequency lesion size. The purpose of this study was to determine, in the beating canine heart, the relationship between CF and radiofrequency lesion size and the accuracy of predicting CF and lesion size by measuring electrogram amplitude, impedance, and electrode temperature. Eight dogs were studied closed chest. Using a 7F catheter with a 3.5 mm irrigated electrode and CF sensor (TactiCath, St. Jude Medical), radiofrequency applications were delivered to 3 separate sites in the right ventricle (30 W, 60 seconds, 17 mL/min irrigation) and 3 sites in the left ventricle (40 W, 60 seconds, 30 mL/min irrigation) at (1) low CF (median 8 g); (2) moderate CF (median 21 g); and (3) high CF (median 60 g). Dogs were euthanized and lesion size was measured. At constant radiofrequency and time, lesion size increased significantly with increasing CF (P<0.01). The incidence of a steam pop increased with both increasing CF and higher power. Peak electrode temperature correlated poorly with lesion size. The decrease in impedance during the radiofrequency application correlated well with lesion size for lesions in the left ventricle but less well for lesions in the right ventricle. There was a poor relationship between CF and the amplitude of the bipolar or unipolar ventricular electrogram, unipolar injury current, and impedance. Radiofrequencylesion size and the incidence of steam pop increase strikingly with increasing CF. Electrogram parameters and initial impedance are poor predictors of CF for radiofrequency ablation. © 2014 American Heart Association, Inc.

  9. Radiofrequency Catheter Ablation Improves the Quality of Life Measured with a Short Form-36 Questionnaire in Atrial Fibrillation Patients: A Systematic Review and Meta-Analysis

    PubMed Central

    Choi, Jong-Il; Kim, Young-Hoon

    2016-01-01

    Background The main purpose of performing radiofrequency catheter ablation (RFCA) in atrial fibrillation (AF) patients is to improve the quality of life (QoL) and alleviate AF-related symptoms. We aimed to determine the qualitative and quantitative effects of RFCA on the QoL in AF patients. Methods We performed a systemic review and meta-analysis using a random effects model. We searched for the studies that reported the physical component summary score (PCS) and mental component summary score (MCS) of the short form-36, a validated system to assess and quantify the QoL, before and after RFCA in AF patients. PCS and MCS are T-scores with a mean of 50 and standard deviation of 10. Results Of the 470 studies identified through systematic search, we included 13 studies for pre-RFCA vs. the post-RFCA analysis and 5 studies for treatment success vs. AF recurrence analyses. In the pre-RFCA vs. post-RFCA analysis, RFCA was associated with a significant increase in both the PCS (weighted mean difference [WMD] = 6.33 [4.81–7.84]; p < 0.001) and MCS (WMD = 7.80 [6.15–9.44]; p < 0.001). The ΔPCS (post-RFCA PCS–pre-RFCA PCS) and ΔMCS values were used for the treatment success vs. AF recurrence analysis. Patients with successful ablation had a higher ΔPCS (WMD = 7.46 [4.44–10.49]; p < 0.001) and ΔMCS (WMD = 7.59 [4.94–10.24]; p < 0.001). Conclusions RFCA is associated with a significant increase in the PCS and MCS in AF patients. Patients without AF recurrence after RFCA had a better improvement in the PCS and MCS than patients who had AF recurrence. PMID:27681507

  10. Feasibility, efficacy, and safety of radiofrequency ablation of atrial fibrillation guided by monitoring of the initial impedance decrease as a surrogate of catheter contact.

    PubMed

    Reichlin, Tobias; Lane, Christopher; Nagashima, Koichi; Nof, Eyal; Chopra, Nagesh; Ng, Justin; Barbhaiya, Chirag; Tadros, Tomas; John, Roy M; Stevenson, William G; Michaud, Gregory F

    2015-04-01

    The initial impedance decrease during radiofrequency (RF) ablation is an indirect marker of catheter contact and lesion formation. We aimed to assess feasibility, efficacy, and safety of an ablation approach guided by initial impedance decrease. A total of 25 patients with paroxysmal AF had point-by-point, wide antral pulmonary vein (PV) isolation. RF applications were aborted if a decrease of at least 5 Ω did not occur in the first 10 seconds; otherwise, ablation was continued for at least 20 seconds. Power was 30 Watts and reduced to 15-25 Watts on the posterior wall. A total of 28% of RF applications were terminated because of inadequate impedance decrease. The remaining lesions showed a median decrease of 7.6 Ω (IQR 5.0-10.7) at 10 seconds and median duration of RF lesions was 38 seconds. Note that, 100 PVs were isolated with 49 rings. PVI occurred before anatomic completion of the ablation ring of adequate lesions in 39/49 (80%) and concurrent with ring completion in 7/49 (14%). Additional lesions were required in 3/49 (6%) rings. After PVI, additional lesions were required to eliminate dormant conduction in 2/47 (4%) and pace-capture on the ablation line in 24/49 vein pairs (49%). During short-term follow-up, 3 nonfatal esophageal injuries and 2 late pericardial effusions occurred. During a mean follow-up of 431 ± 87 days, 21/25 patients (84%) remained free of recurrent symptomatic atrial arrhythmias. PVI guided by initial impedance decrease is feasible and results in PVI concurrent with or before completion of the ablation ring in 94% of patients. Single procedure efficacy after one year of follow-up was 84%. Near-term complications suggest that deeper lesions are created, indicating that further reduction of RF-power and duration is warranted. © 2015 Wiley Periodicals, Inc.

  11. [Variations of pulmonary venous drainage and venous ostium index detection in atrial fibrillation patients prior to radiofrequency catheter ablation by MDCT pulmonary venography].

    PubMed

    Shan, Fei; Zhang, Zhi-Yong; Chen, Gang; Miao, Xi-Yin; Liu, Hao; Zhang, Li-Jun; Zeng, Liang-Bin

    2007-04-01

    To evaluate variations of pulmonary venous drainage and venous ostium index (VOI) in patients with atrial fibrillation (AF) prior to radio-frequency catheter ablation (RFCA) by MDCT pulmonary venography. 16-detector row CT pulmonary venography was performed in 64 AF patients referred to RFCA from June, 2005 to May, 2006. Variations in pulmonary venous drainage were observed in volume render imagines. Anterior-posterior and superior-inferior diameters of pulmonary venous ostium were measured on maximum intensity projection images. VOI derived from left superior, left inferior, right superior, right inferior pulmonary veins and variations in pulmonary venous drainage were calculated. Classic pulmonary veins anatomy was found in 11 patients (17.18%), early branching veins in 45 patients (70.31%), left common ostium in 5 patients (7.81%), right common ostia in 1 patient, right accessory (middle) pulmonary vein in 5 patients (7.81%) and left accessory (middle) pulmonary vein in 1 patient (1.56%). VOI of homolateral pulmonary veins and bilateral superior pulmonary veins were similar (P > 0.05) while there was a significant difference on VOIs derived from left superior and right inferior; two inferior, left inferior versus right superior veins (P < 0.05). Right inferior pulmonary venous ostium was most rounded and had the highest index (0.88) and left inferior pulmonary venous ostium was most oval and had the lowest index (0.72). Multidetector row CT pulmonary venography (MDCT-PV) could provide valuable informations on pulmonary venous anatomy in AF patients referred to RFCA and should be used as a routine examination prior to the operation.

  12. Long-Term Outcomes of Radio-Frequency Catheter Ablation on Ventricular Tachycardias Due to Arrhythmogenic Right Ventricular Cardiomyopathy: A Single Center Experience

    PubMed Central

    Xue, Yumei; Fang, Xianhong; Huang, Jun; Liu, Yang; Deng, Hai; Liang, Yuanhong; Liao, Zili; Liu, Fangzhou; Lin, Weidong; Zhan, Xianzhang; Wu, Shulin

    2017-01-01

    Aims To summarize our experience of radiofrequency catheter ablation (RFCA) for recurrent drug-refractory ventricular tachycardias (VTs) due to arrhythmogenic right ventricular cardiomyopathy (ARVC) in our center over the past 11 years and its related factors. Methods and Results We reviewed 48 adults (mean age 39.9 ± 12.9 years, range: 14 to 65) who met the present ARVC diagnostic criteria and accepted RFCA for VTs from December 2004 to April 2016. The patients received a total of 70 procedures using two ablation approaches, the endocardial approach in 52 RFCAs, and the combined epicardial and endocardial approach (the combined approach) in 18 RFCAs. Kaplan-Meier survival analysis showed that the combined approach achieved better acute procedural success (p = 0.003) and better long-term outcomes (p = 0.028) than the endocardial approach. Patients who obtained acute procedural success with non-inducibility had better long-term outcomes (p < 0.001). COX regression of multivariate analysis showed that procedural success was the only factor that benefited long-term outcome, irrespective of the endocardial or the combined approach (p = 0.001). The rate of sudden cardiac death (SCD) in patients without procedural success was significantly higher than that in patients with procedural success (p = 0.005). All patients without implantable cardioverter defibrillator (ICD) implantation who had successful final RFCA survived. Conclusions The combined approach resulted in better procedural success and long-term VT-free survival compared with the endocardial approach in ARVC patients with recurrent VTs. Acute procedural success with non-inducibility was strongly related to better long-term VT-free survival and reduced SCD, irrespective of whether this was achieved by the endocardial approach or the combined approach. PMID:28122031

  13. Left atrial appendage flow velocity and time from P-wave onset to tissue Doppler-derived A' predict atrial fibrillation recurrence after radiofrequency catheter ablation.

    PubMed

    Fukushima, Keiko; Fukushima, Noritoshi; Ejima, Koichiro; Kato, Ken; Sato, Yasuto; Uematsu, Shoko; Arai, Kotaro; Manaka, Tetsuyuki; Takagi, Atsushi; Ashihara, Kyomi; Shoda, Morio; Hagiwara, Nobuhisa

    2015-07-01

    Atrial fibrillation (AF) is associated with atrial remodeling. We investigate the abilities of preprocedural echocardiographic parameters reflecting atrial remodeling to predict AF recurrence after radiofrequency catheter ablation (RFCA) for paroxysmal AF (PAF). Preprocedural echocardiographic parameters were measured during sinus rhythm in 105 patients with PAF undergoing RFCA. Electrical remodeling was assessed by the time from the onset of the P-wave to the peak A'-wave on the tissue Doppler imaging (PA-TDI), functional remodeling was assessed by the left atrial appendage flow velocity (LAAFV), and structural remodeling was assessed by the left atrial volume index (LAVI). PA-TDI, LAAFV, and LAVI values were divided into tertiles, and their abilities to predict AF recurrence were assessed using Cox regression analysis. AF recurrence occurred in 39/105 (37.1%) patients. After adjustment for confounders, the rate of AF recurrence was significantly higher in the highest tertile of PA-TDI compared with the lowest tertile (≥151.3 msec vs. <131.0 msec; hazard ratio [HR]: 2.477, 95% confidence interval [CI]: 1.031-5.950; P = 0.042), and in the lowest tertile of LAAFV compared with the highest tertile (<48.5 cm/sec vs. ≥64.9 cm/sec; HR: 2.680, 95% CI: 1.136-6.318; P = 0.024). The risk of AF recurrence was also higher in the highest tertile of LAVI (≥34.2 mL/m(2) ) compared with the lowest tertile, but this difference was not significant (HR: 2.146, 95% CI: 0.834-5.523; P = 0.113). LAAFV (reflecting functional remodeling) and PA-TDI (reflecting electrical remodeling) are independent predictors of AF recurrence after RFCA for PAF. © 2014, Wiley Periodicals, Inc.

  14. Radiofrequency catheter ablation of atrial fibrillation guided by spectral mapping of atrial fibrillation nests in sinus rhythm.

    PubMed

    Mateos, José Carlos Pachón; Mateos, Enrique I Pachón; Lobo, Tasso J; Pachón, Maria Zélia C; Mateos, Juán Carlos Pachón; Pachón, Denilda Queiroz V; Vargas, Remy Nelson A; Piegas, Leopoldo S; Jatene, Adib D

    2007-09-01

    Two types of myocardia can be observed through the endocardial spectral mapping (SM) in sinus rhythm: the compact type with a smooth spectrum and the fibrillar type with a segmented spectrum (atrial fibrillation nests). During the atrial fibrillation (AF), the compact type has an organized activation and low frequency (passive), whereas the fibrillar type has a rather disorganized activation and high frequency (active/resonant), with both being activated by high-frequency sustained tachycardia--the background tachycardia (BT). To describe the treatment of AF by the ablation of the AF nests and BT. 1) Catheter ablation of the AF nests with RF [4/8 mm-60 masculine/30-40 J/30s] guided by SM in sinus rhythm, outside the pulmonary vein; 2) atrial stimulation -300 ppm; 3) Additional ablation of the AF nests if AF is induced; 4) Focal ablation if BT and/or Flutter is induced; 5) Clinical follow-up+ ECG+ Holter. A total of 50+/-18 AF nests/patient were treated. After 11.3+/-8 m, 81 patients (88%) did not present AF (28.3% with antiarrhythmic drugs). After the ablation of the AF nests, AF was not reinduced in 61 patients (71%) and BT was induced and treated in 24 patients (26%). There were two episodes of pericardial bleeding (1 treated clinically and 1 surgically), caused by sheaths that are no longer used The SM in sinus rhythm can be used in the ablation of AF nests. During the AF, the AF nests present a reactive-resonant pattern and the compact myocardium is passive, stimulated by the high frequency of the BT. After the ablation of the AF nests and the BT, it was not possible to reinduce the sustained AF. The Ablation of AF nests outside the pulmonary veins showed to be safe and highly effective in the cure and/or clinical control of the AF.

  15. The role of multidetector CT in the evaluation of the left atrium and pulmonary veins anatomy before and after radio-frequency catheter ablation for atrial fibrillation. Preliminary results and work in progress. Technical note.

    PubMed

    Centonze, Maurizio; Del Greco, Maurizio; Nollo, Giandomenico; Ravelli, Flavia; Marini, Massimiliano; Della Sala, Sabino Walter; Dalla Palma, Francesco

    2005-01-01

    Radio-frequency catheter ablation (RFCA) of the distal pulmonary veins is increasingly being used to treat recurrent or refractory atrial fibrillation that doesn't respond to pharmacologic therapy or cardioversion. Successful RFCA of atrial fibrillation depends on the pre-procedural understanding of the complex anatomy of the distal pulmonary veins and the left atrium. Aim of this paper is to describe the technical main features that characterise the multidetector helical computed tomography in the evaluation of this anatomic region before and after RFCA procedure. The 3D post-processing techniques useful for pre-RFCA planning are straightforward.

  16. Using Conventional Sequences in L2 French

    ERIC Educational Resources Information Center

    Forsberg, Fanny

    2010-01-01

    By means of a phraseological identification method, this study provides a general description of the use of conventional sequences (CSs) in interviews at four different levels of spoken L2 French as well as in interviews with native speakers. Use of conventional sequences is studied with regard to overall quantity, category distribution and type…

  17. Urinary catheters

    MedlinePlus

    ... provider's office. An indwelling catheter has a small balloon inflated on the end of it. This prevents ... When the catheter needs to be removed, the balloon is deflated. CONDOM CATHETERS Condom catheters can be ...

  18. Reinnervation of renal afferent and efferent nerves at 5.5 and 11 months after catheter-based radiofrequency renal denervation in sheep.

    PubMed

    Booth, Lindsea C; Nishi, Erika E; Yao, Song T; Ramchandra, Rohit; Lambert, Gavin W; Schlaich, Markus P; May, Clive N

    2015-02-01

    Previous studies indicate that catheter-based renal denervation reduces blood pressure and renal norepinephrine spillover in human resistant hypertension. The effects of this procedure on afferent sensory and efferent sympathetic renal nerves, and the subsequent degree of reinnervation, have not been investigated. We therefore examined the level of functional and anatomic reinnervation at 5.5 and 11 months after renal denervation using the Symplicity Flex catheter. In normotensive anesthetized sheep (n=6), electric stimulation of intact renal nerves increased arterial pressure from 99±3 to 107±3 mm Hg (afferent response) and reduced renal blood flow from 198±16 to 85±20 mL/min (efferent response). In a further group (n=6), immediately after denervation, renal sympathetic nerve activity was absent and the responses to electric stimulation were abolished. At 11 months after denervation (n=5), renal sympathetic nerve activity and the responses to electric stimulation were at normal levels. Immunohistochemical staining for renal efferent (tyrosine hydroxylase) and renal afferent nerves (calcitonin gene-related peptide), as well as renal norepinephrine levels, was normal 11 months after denervation. Findings at 5.5 months after denervation were similar (n=5). In summary, catheter-based renal denervation effectively ablated the renal afferent and efferent nerves in normotensive sheep. By 11 months after denervation the functional afferent and efferent responses to electric stimulation were normal. Reinnervation at 11 months after denervation was supported by normal anatomic distribution of afferent and efferent renal nerves. In view of this evidence, the mechanisms underlying the prolonged hypotensive effect of catheter-based renal denervation in human resistant hypertension need to be reassessed.

  19. Biophysical parameters during radiofrequency catheter ablation of scar-mediated ventricular tachycardia: epicardial and endocardial applications via manual and magnetic navigation.

    PubMed

    Bourke, Tara; Buch, Eric; Mathuria, Nilesh; Michowitz, Yoav; Yu, Ricky; Mandapati, Ravi; Shivkumar, Kalyanam; Tung, Roderick

    2014-11-01

    There is a paucity of data on biophysical parameters during radiofrequency ablation of scar-mediated ventricular tachycardia (VT). Data were collected from consecutive patients undergoing VT ablation with open-irrigation. Complete data were available for 372 lesions in 21 patients. The frequency of biophysical parameter changes were: >10Ω reduction (80%), bipolar EGM reduction (69%), while loss of capture was uncommon (32%). Unipolar injury current was seen in 72% of radiofrequency applications. Both EGM reduction and impedance drop were seen in 57% and a change in all 3 parameters was seen in only 20% of lesions. Late potentials were eliminated in 33%, reduced/modified in 56%, and remained after ablation in 11%. Epicardial lesions exhibited an impedance drop (90% vs. 76%, P = 0.002) and loss of capture (46% vs. 27%, P < 0.001) more frequently than endocardial lesions. Lesions delivered manually exhibited a >10Ω impedance drop (83% vs. 71%, P = 0.02) and an EGM reduction (71% vs. 40%, P < 0.001) more frequently than lesions applied using magnetic navigation, although loss of capture, elimination of LPs, and a change in all 3 parameters were similarly observed. VT ablation is inefficient as the majority of radiofrequency lesions do not achieve more than one targeted biophysical parameter. Only one-third of RF applications targeted at LPs result in complete elimination. Epicardial ablation within scar may be more effective than endocardial lesions, and lesions applied manually may be more effective than lesions applied using magnetic navigation. New technologies directed at identifying and optimizing ablation effectiveness in scar are clinically warranted. © 2014 Wiley Periodicals, Inc.

  20. BIOPHYSICAL PARAMETERS DURING RADIOFREQUENCY CATHETER ABLATION OF SCAR-MEDIATED VENTRICULAR TACHYCARDIA: EPICARDIAL AND ENDOCARDIAL APPLICATIONS VIA MANUAL AND MAGNETIC NAVIGATION

    PubMed Central

    Bourke, Tara; Buch, Eric; Mathuria, Nilesh; Michowitz, Yoav; Yu, Ricky; Mandapati, Ravi; Shivkumar, Kalyanam; Tung, Roderick

    2014-01-01

    Background There is a paucity of data on biophysical parameters during radiofrequency ablation of scar-mediated ventricular tachycardia (VT). Methods and Results Data was collected from consecutive patients undergoing VT ablation with open-irrigation. Complete data was available for 372 lesions in 21 patients. The frequency of biophysical parameter changes were: >10Ω reduction (80%), bipolar EGM reduction (69%), while loss of capture was uncommon (32%). Unipolar injury current was seen in 72% of radiofrequency applications. Both EGM reduction and impedance drop were seen in 57% and a change in all 3 parameters was seen in only 20% of lesions. Late potentials were eliminated in 33%, reduced/modified in 56%, and remained after ablation in 11%. Epicardial lesions exhibited an impedance drop (90% vs 76%, p=0.002) and loss of capture (46% vs 27%, p<0.001) more frequently than endocardial lesions. Lesions delivered manually exhibited a >10Ω impedance drop (83% vs 71%, p=0.02) and an EGM reduction (71% vs 40%, p< 0.001) more frequently than lesions applied using magnetic navigation, although loss of capture, elimination of LPs, and a change in all 3 parameters were similarly observed. Conclusions VT ablation is inefficient as the majority of radiofrequency lesions do not achieve more than one targeted biophysical parameter. Only one-third of RF applications targeted at LPs result in complete elimination. Epicardial ablation within scar may be more effective than endocardial lesions and lesions applied manually may be more effective than lesions applied using magnetic navigation. New technologies directed at identifying and optimizing ablation effectiveness in scar are clinically warranted. PMID:24946895

  1. Dual-enhancement cardiac computed tomography for assessing left atrial thrombus and pulmonary veins before radiofrequency catheter ablation for atrial fibrillation.

    PubMed

    Hur, Jin; Pak, Hui-Nam; Kim, Young Jin; Lee, Hye-Jeong; Chang, Hyuk-Jae; Hong, Yoo Jin; Choi, Byoung Wook

    2013-07-15

    Noninvasive imaging that provides anatomic information while excluding intracardiac thrombus would be of significant clinical value for patients referred for catheter ablation of atrial fibrillation (AF). This study assessed the diagnostic performance of a dual-enhancement single-phase cardiac computed tomography (CT) protocol for thrombus and circulatory stasis detection in AF patients before catheter ablation. We studied 101 consecutive symptomatic AF patients (71 men and 30 women; mean age, 61.8 years) who were scheduled to have catheter ablation. All patients had undergone pre-AF ablation CT imaging and transesophageal echocardiography on the same day. CT was performed with prospective electrocardiographic gating, and scanning began 180 seconds after the test bolus. Mean left atrial appendage (LAA)/ascending aorta Hounsfield unit (HU) ratios were measured on CT images. Among the 101 patients, 9 thrombi and 18 spontaneous echo contrasts were detected by transesophageal echocardiography. The overall sensitivity, specificity, positive predictive value, and negative predictive value of CT for the detection of thrombi in the LAA were 89%, 100%, 100%, and 99%, respectively. The mean LAA/ascending aorta HU ratios were significantly different between thrombus and circulatory stasis (0.17 vs 0.33, p = 0.002). Dual-enhancement single-scan cardiac CT is a sensitive modality for detecting and differentiating LAA thrombus and circulatory stasis.

  2. [Catheter ablation of atrial flutter and paroxysmal atrial fibrillation].

    PubMed

    Márquez, Manlio F

    2003-01-01

    Radiofrequency catheter ablation has emerged as a curative therapy for atrial flutter based on studies demonstrating the role of the cavotricuspid isthmus. With a high rate of success and minimal complications, catheter ablation is the therapy of choice for patients with the common type of atrial flutter. Left atrial flutter, non-cavotricuspid isthmus dependent, and those associated with heart disease have a worst outcome with catheter ablation. Radiofrequency catheter ablation has also emerged as a curative therapy for paroxysmal atrial fibrillation based on studies demonstrating the role of triggering foci in the pulmonary veins for the initiation of atrial fibrillation. Catheter ablation is performed by a transseptal approach using radiofrequency energy at the ostium of each pulmonary vein. Mapping is guided by special catheters. Sequential radiofrequency applications eliminates or dissociates pulmonary vein muscle activity. Although complications exists, this is the only curative method for these patients.

  3. Polymorphism rs2200733 at chromosome 4q25 is associated with atrial fibrillation recurrence after radiofrequency catheter ablation in the Chinese Han population

    PubMed Central

    Chen, Feifei; Yang, Yanzong; Zhang, Rongfeng; Zhang, Shulong; Dong, Yingxue; Yin, Xiaomeng; Chang, Dong; Yang, Zhiqiang; Wang, Kejing; Gao, Lianjun; Xia, Yunlong

    2016-01-01

    To test polymorphisms rs2200733 (chromosome 4q25) and rs2106261 (ZFHX3) were associated with AF recurrence after catheter ablation in a Chinese Han cohort. A total of 235 AF patients who underwent catheter ablation were recruited consecutively. Two polymorphisms were amplified by polymerase chain reaction and genotyped using high resolution melting analysis. Primary endpoints for AF recurrence were defined as the time to the first recurrence of atrial tachycardia/flutter/fibrillation (AT/AF). AT/AF recurrence was observed in 76 patients (35%). Allelic analysis demonstrated that rs2200733 was strongly associated with AF recurrence after ablation (P = 0.011) and the minor allele T increased the risk for recurrence (OR = 1.715). Diameters of the right atrium as well as the left and right superior pulmonary veins (PVs) were associated with rs2200733 in different genetic models (P = 0.040, 0.047 and 0.028, respectively). No significant association was detected between rs2106261 and AT/AF recurrence after ablation or atrial/PV diameters in any models. On multivariate Cox regression analysis, only rs2200733 was an independent factor of AF recurrence after ablation (HR = 0.532, P = 0.022). In Chinese Han population, rs2200733 but not rs2106261 is associated with AT/AF recurrence after ablation. The patients with genotype TT have larger size of right atrium and superior PVs than those of CC genotype. The findings suggest that rs2200733 may play a key role in regulating proper development and differentiation of atria/PVs. PMID:27158361

  4. Efficacy and effects on cardiac function of radiofrequency catheter ablation vs. direct current cardioversion of persistent atrial fibrillation with left ventricular systolic dysfunction

    PubMed Central

    Wang, Maojing; Cai, Shanglang; Ding, Wei; Deng, Yujie; Zhao, Qing

    2017-01-01

    Objective To evaluate the effect of catheter ablation vs. direct current synchronized cardioversion (DCC) in patients with persistent atrial fibrillation (AF) and left ventricular systolic dysfunction, and to define baseline features of patients that will get more benefit from ablation. Methods From July 2013 to October 2014, 97 consecutive single-center patients with persistent AF and symptomatic heart failure (left ventricular ejection fraction (LVEF) <50%) underwent DCC followed by amiodarone (n = 40) or circumferential pulmonary vein isolation (PVI; n = 57) according to patient’s preference were recruited in the study. Post-ablation recurrence was treated with atrial roof and mitral isthmus lines ablation with or without PVI based on restoration or not of pulmonary vein (PV) potential conduction. Study outcomes were 12-month rate of sustained sinus rhythm (SR) and cardiac function. Baseline characteristics were compared between patients with and without cardiac function improvement post ablation. Results With similarly distributed characteristics at baseline, ablation (mean 1.8 procedures) relative to DCC yielded significantly higher level of 12-month SR maintenance rate (68.42% vs. 35%, P = 0.001); and better LVEF and New York Heart Association class. with significant effect for DCC only in maintained SR cases. Post ablation LVEF increased (>20% or to over 55%) in 31 (54.39%) patients with worse baseline cardiac function and ventricular rate control. Conclusions Catheter ablation relative to cardioversion of persistent AF with symptomatic heart failure yielded better 12-month SR maintenance and cardiac function. Compared with non-responders, patients with improved LVEF post-ablation had poorer ventricular rate control and cardiac function at baseline, suggesting a significant component of tachycardia-induced cardiomyopathy in this group. PMID:28350861

  5. Comparison of radiofrequency catheter ablation of drivers and circumferential pulmonary vein isolation in atrial fibrillation: a noninferiority randomized multicenter RADAR-AF trial.

    PubMed

    Atienza, Felipe; Almendral, Jesús; Ormaetxe, José Miguel; Moya, Angel; Martínez-Alday, Jesús Daniel; Hernández-Madrid, Antonio; Castellanos, Eduardo; Arribas, Fernando; Arias, Miguel Ángel; Tercedor, Luis; Peinado, Rafael; Arcocha, Maria Fe; Ortiz, Mercedes; Martínez-Alzamora, Nieves; Arenal, Angel; Fernández-Avilés, Francisco; Jalife, José

    2014-12-16

    Empiric circumferential pulmonary vein isolation (CPVI) has become the therapy of choice for drug-refractory atrial fibrillation (AF). Although results are suboptimal, it is unknown whether mechanistically-based strategies targeting AF drivers are superior. This study sought to determine the efficacy and safety of localized high-frequency source ablation (HFSA) compared with CPVI in patients with drug-refractory AF. This prospective, multicenter, single-blinded study of 232 patients (age 53 ± 10 years, 186 males) randomized those with paroxysmal AF (n = 115) to CPVI or HFSA-only (noninferiority design) and those with persistent AF (n = 117) to CPVI or a combined ablation approach (CPVI + HFSA, superiority design). The primary endpoint was freedom from AF at 6 months post-first ablation procedure. Secondary endpoints included freedom from atrial tachyarrhythmias (AT) at 6 and 12 months, periprocedural complications, overall adverse events, and quality of life. In paroxysmal AF, HFSA failed to achieve noninferiority at 6 months after a single procedure but, after redo procedures, was noninferior to CPVI at 12 months for freedom from AF and AF/AT. Serious adverse events were significantly reduced in the HFSA group versus CPVI patients (p = 0.02). In persistent AF, there were no significant differences between treatment groups for primary and secondary endpoints, but CPVI + HFSA trended toward more serious adverse events. In paroxysmal AF, HFSA failed to achieve noninferiority at 6 months but was noninferior to CPVI at 1 year in achieving freedom of AF/AT and a lower incidence of severe adverse events. In persistent AF, CPVI + HFSA offered no incremental value. (Radiofrequency Ablation of Drivers of Atrial Fibrillation [RADAR-AF]; NCT00674401). Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  6. Management and Outcome of Periprocedural Cardiac Perforation and Tamponade with Radiofrequency Catheter Ablation of Cardiac Arrhythmias: A Single Medium-Volume Center Experience.

    PubMed

    Mujović, Nebojša; Marinković, Milan; Marković, Nebojša; Kocijančić, Aleksandar; Kovačević, Vladan; Simić, Dragan; Ristić, Arsen; Stanković, Goran; Miličić, Biljana; Putnik, Svetozar; Vujisić-Tešić, Bosiljka; Potpara, Tatjana S

    2016-10-01

    Cardiac tamponade (CT) is a life-threatening complication of radiofrequency ablation (RFA). The course and outcome of CT in low-to-medium volume electrophysiology centers are underreported. We analyzed the incidence, management and outcomes of CT in 1500 consecutive RFAs performed in our center during 2011-2016. Of 1500 RFAs performed in 1352 patients (age 55 years, interquartile range: 41-63), 569 were left-sided procedures (n = 406 with transseptal access). Conventional RFA or irrigated RFA was performed in 40.9% and 59.1% of procedures, respectively. Ablation was performed mostly for atrioventricular nodal reentrant tachycardia (25.4%), atrial fibrillation (AF; 18.5%), atrial flutter (18.4%), accessory pathway (16.5%) or idiopathic ventricular arrhythmia (VA; 12.3%), and rarely for structural VA (2.1%). CT occurred in 12 procedures (0.8%): 10 AF ablations, 1 idiopathic VA and 1 typical atrial flutter ablation. Factors significantly associated with CT were older age, pre-procedural oral anticoagulation, left-sided procedures, transseptal access, AF ablation, irrigated RFA and longer fluoroscopy time (on univariate analysis), and AF ablation (on multivariable analysis). The perforation site was located in the left atrium (n = 7), right atrium (n = 3), or in the left ventricle or coronary sinus (n = 1 each). Upon pericardiocentesis, two patients underwent urgent cardiac surgery because of continued bleeding. There was no fatal outcome. During the follow-up of 19 ± 14 months, eight patients were arrhythmia free. Incidence of RFA-related CT in our medium-volume center was low and significantly associated with AF ablation. The outcome of CT was mostly favorable after pericardiocentesis, but readily accessible cardiothoracic surgery back-up should be mandatory in RFA centers.

  7. Low P-wave amplitude (<0.1 mV) in lead I is associated with displaced inter-atrial conduction and clinical recurrence of paroxysmal atrial fibrillation after radiofrequency catheter ablation.

    PubMed

    Park, Jin-Kyu; Park, Junbeom; Uhm, Jae-Sun; Joung, Boyoung; Lee, Moon-Hyoung; Pak, Hui-Nam

    2016-03-01

    We hypothesized that P-wave amplitude in lead I is related to left atrial (LA) remodelling and inter-atrial conduction pattern, and has a predictive value for recurrence after radiofrequency catheter ablation (RFCA) among patients with paroxysmal atrial fibrillation (PAF). A total of 525 consecutive patients with PAF (76% male, 56 ± 12 years old) who underwent RFCA were included. We compared pre-procedural sinus rhythm electrocardiograms without antiarrhythmic drug effect with LA volume (CT), LA voltage (NavX), the earliest activation site (EAS) conduction pattern of LA, and clinical recurrence rate. P-wave amplitude in lead I was significantly lower in patients with recurrence than in those that remained in sinus rhythm (P < 0.001) during 21 ± 10-month follow-up. P-wave amplitude in lead I was linearly correlated with LA voltage (β = 2.52, 95% CI 0.606-4.425, P = 0.010), LA conduction velocity (β = 1.91, 95% CI 0.941-2.876, P < 0.001), and low septal displacement of EAS (β = -1.67, 95% CI -2.352 to -0.996, P < 0.001). P-wave amplitudes <0.1 mV in lead I were independently associated with clinical recurrence of AF on multivariate Cox regression analysis (adjusted HR 2.163, 95% CI 1.307-3.581, P = 0.003). The integrated area under the curves was 0.705 (95% CI 0.655-0.755). Low P-wave amplitude (<0.1 mV) in lead I is related to LA remodelling and displaced inter-atrial conduction pattern to low septum, and independently predicts clinical recurrence after RFCA in patients with PAF. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

  8. Radiofrequency Neurotomy

    MedlinePlus

    ... 24 hours after your procedure. Avoid using a heating pad on the injection sites. Avoid baths for ... Smith AD, et al. Cervical radiofrequency neurotomy reduces central hyperexcitability and improves neck movement in individuals with ...

  9. Radiofrequency: Thermage.

    PubMed

    Polder, Kristel D; Bruce, Suzanne

    2011-05-01

    Nonablative procedures for facial rejuvenation have become increasingly popular. One such method to improve laxity and diminish rhytids is monopolar capacitively coupled radiofrequency (MRF). The authors discuss clinical studies using MRF. The authors also discuss their clinical experiences as well as recommendations for optimal results. MRF using the Thermage CPT system (Solta Medical, Hayward, California) offers minimal downtime with a favorable side-effect profile. Although there are many radiofrequency devices on the market for aesthetic use, MRF has the most clinical trials to date to support its use as an effective, evidence-based modality to improve rhytids and tighten the skin. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Esophageal papilloma: Flexible endoscopic ablation by radiofrequency

    PubMed Central

    del Genio, Gianmattia; del Genio, Federica; Schettino, Pietro; Limongelli, Paolo; Tolone, Salvatore; Brusciano, Luigi; Avellino, Manuela; Vitiello, Chiara; Docimo, Giovanni; Pezzullo, Angelo; Docimo, Ludovico

    2015-01-01

    Squamous papilloma of the esophagus is a rare benign lesion of the esophagus. Radiofrequency ablation is an established endoscopic technique for the eradication of Barrett esophagus. No cases of endoscopic ablation of esophageal papilloma by radiofrequency ablation (RFA) have been reported. We report a case of esophageal papilloma successfully treated with a single session of radiofrequency ablation. Endoscopic ablation of the lesion was achieved by radiofrequency using a new catheter inserted through the working channel of endoscope. The esophageal ablated tissue was removed by a specifically designed cup. Complete ablation was confirmed at 3 mo by endoscopy with biopsies. This case supports feasibility and safety of as a new potential indication for BarrxTM RFA in patients with esophageal papilloma. PMID:25789102

  11. Video assisted thoracoscopic and cardioscopic radiofrequency Maze ablation.

    PubMed

    Inoue, Y; Yozu, R; Mitsumaru, A; Ueda, T; Hiraki, O; Sano, Y; Kawada, S

    1997-01-01

    The authors examined the feasibility of transthoracic radio frequency Maze ablation of atrial fibrillation using video assisted thoracoscopy and cardioscopy in the experimental setting of a beating porcine heart. In six pigs under general anesthesia, the left atrium was viewed using a video assisted thoracoscopy system (VATS), and radiofrequency linear ablation of the left atrial wall was carried out using a radiofrequency ablation catheter (HAT200S:OSYPKA) inserted through a trocar port. The right atrium was also ablated in the same manner under VATS. In six other pigs, intravenous radiofrequency ablation by cardioscopic catheter device was carried out. Atrial fibrillation was provoked by acetylcholine injection plus rapid atrial pacing. The thoracoscopic visual field created for radiofrequency catheter ablation from a transthoracic approach and the cardioscopic visual field from an intravenous approach were sufficient, and safe positioning of the ablation catheter device on the atrial epicardium and endocardium, which enabled linear ablation of the atrium, was obtained. The Optimal setting for ablation was 70-80 degrees C/ 30 sec duration per each ablation. This process was monitored and documented by a video system through the thoracoscope and cardioscope, and results were confirmed by postmortem macrohistologic examination. In conclusion, the authors' results suggest the potential usefulness of the combination of transthoracic radiofrequency catheter ablation with video assisted thoracoscopic and cardioscopic linear ablation of atrial fibrillation, and the possibility that use of this system might eliminate the need for open heart Maze surgery.

  12. Radiofrequency Identification

    PubMed Central

    Jones, Terry L.

    2017-01-01

    A national campaign is underway to increase the amount of time staff nurses spend at the bedside of hospitalized patients through redesign of the work environment. This kind of work redesign requires robust data depicting what nurses do and how they spend their time. Historically, these kinds of data have been difficult, costly, and time consuming to collect. Wireless capture of data on the movement of humans within the work environment (ie, time and motion) is now possible through radiofrequency identification technology. When small tracking devices the size of a quarter are affixed to their clothing, the movement of nurses throughout a patient care unit can be monitored. The duration and frequency of patient interaction are captured along with the duration of time spent in other locations of interest to include nurses’ station, supply room, medication room, doctors’ station, electronic documentation stations, family waiting rooms, and the hallway. Patterns of nurse movement and time allocation can be efficiently identified, and the effects of staffing practices, workflows, and unit layout evaluated. Integration of radiofrequency identification time and motion data with other databases enables nurse leaders to link nursing time to important cost and quality outcomes. Nurse leaders should explore the usefulness of radiofrequency identification technology in addressing data needs for nurse time and motion. PMID:22592451

  13. Catheter Ablation

    MedlinePlus

    ... you during the procedure. Machines will measure your heart’s activity. All types of ablation require cardiac catheterization to place flexible tubes, or catheters, inside your heart to make the scars. Your doctor will clean ...

  14. Umbilical catheters

    MedlinePlus

    ... arteries and one umbilical vein in the umbilical cord. After the umbilical cord is cut off, the health care provider can find these blood vessels. The catheters are placed into the blood vessel, ... Complications include: Interruption of the blood flow ...

  15. Catheter Embolization

    MedlinePlus

    ... the scrotum that may be a cause of infertility. Catheter embolization may be used alone or combined ... in patients with diabetes or other pre-existing kidney disease. top of page What are the limitations of ...

  16. Endovenous radiofrequency ablation of superficial and perforator veins.

    PubMed

    Roth, Steven M

    2007-10-01

    Radiofrequency ablation of superficial and perforator veins for venous insufficiency has emerged as a leading alternative to traditional vein stripping operations. This percutaneous technique can be performed in less than an hour using local anesthetic or sedation. The VNUS Closure catheters (VNUS Medical Technologies, San Jose, California) work by resistive heating in the vein wall that is constantly monitored through a feedback loop to the VNUS Closure generator. Side effects are less than with other endovenous ablation techniques and patients resume normal activity immediately. The new ClosureFAST catheter is an important advancement that combines the speed of endovenous laser ablation with the expected fewer side effects of radiofrequency ablation.

  17. Urinary catheter - infants

    MedlinePlus

    Bladder catheter - infants; Foley catheter - infants; Urinary catheter - neonatal ... Fanaroff AA, Walsh MC, eds. Fanaroff and Martin's Neonatal-Perinatal Medicine . 10th ed. Philadelphia, PA: Elsevier Saunders; ...

  18. [Cosmetic radiofrequency].

    PubMed

    Huth, J

    2010-01-01

    Cosmetic radio frequency uses an electric current of high frequency that generates heat through the subcutaneous tissues enough to break the collagen fibers and allow synthesis of a neo-collagen. It permits cutaneous resurfacing, improving the tone and quality of the skin (wrinkles and enlarged pores), and delicately reshaping facial volumes. The principle of a type Ellman monopolar radiofrequency at a rate of 4 MHz Pellevé, Surgitron Dual RF S 5 is described. Its use inclines more towards anti-aging and natural rejuvenation of the face, neck and neckline. It may be associated with other rejuvenation techniques such as fillers and botulinum toxin within certain time limits.

  19. Thermal compression and molding of atherosclerotic vascular tissue with use of radiofrequency energy: implications for radiofrequency balloon angioplasty

    SciTech Connect

    Lee, B.I.; Becker, G.J.; Waller, B.F.; Barry, K.J.; Connolly, R.J.; Kaplan, J.; Shapiro, A.R.; Nardella, P.C.

    1989-04-01

    The combined delivery of pressure and thermal energy may effectively remodel intraluminal atherosclerotic plaque and fuse intimal tears. To test these hypotheses with use of a non-laser thermal energy source, radiofrequency energy was delivered to postmortem human atherosclerotic vessels from a metal hot-tip catheter, block-mounted bipolar electrodes and from a prototype radiofrequency balloon catheter. Sixty-two radiofrequency doses delivered from a metal electrode tip produced dose-dependent ablation of atherosclerotic plaque, ranging from clean and shallow craters with histologic evidence of thermal compression at doses less than 40 J to tissue charring and vaporization at higher (greater than 80 J) doses. Lesion dimensions ranged between 3.14 and 3.79 mm in diameter and 0.20 and 0.47 mm in depth. Tissue perforation was not observed. To test the potential for radiofrequency fusion of intimal tears, 5 atm of pressure and 200 J radiofrequency energy were delivered from block-mounted bipolar electrodes to 48 segments of human atherosclerotic aorta, which had been manually separated into intima-media and media-adventitial layers. Significantly stronger tissue fusion resulted (28.5 +/- 3.3 g) with radiofrequency compared with that with pressure alone (4.8 +/- 0.26 g; p less than 0.0001). A prototype radiofrequency balloon catheter was used to deliver 3 atm of balloon pressure with or without 200 J radiofrequency energy to 20 postmortem human atherosclerotic arterial segments. In 10 of 10 radiofrequency-treated vessels, thermal molding of both normal and atherosclerotic vessel wall segments resulted with increased luminal diameter and histologic evidence of medial myocyte damage.

  20. Thermal compression and molding of atherosclerotic vascular tissue with use of radiofrequency energy: implications for radiofrequency balloon angioplasty.

    PubMed

    Lee, B I; Becker, G J; Waller, B F; Barry, K J; Connolly, R J; Kaplan, J; Shapiro, A R; Nardella, P C

    1989-04-01

    The combined delivery of pressure and thermal energy may effectively remodel intraluminal atherosclerotic plaque and fuse intimal tears. To test these hypotheses with use of a non-laser thermal energy source, radiofrequency energy was delivered to postmortem human atherosclerotic vessels from a metal "hot-tip" catheter, block-mounted bipolar electrodes and from a prototype radiofrequency balloon catheter. Sixty-two radiofrequency doses delivered from a metal electrode tip produced dose-dependent ablation of atherosclerotic plaque, ranging from clean and shallow craters with histologic evidence of thermal compression at doses less than 40 J to tissue charring and vaporization at higher (greater than 80 J) doses. Lesion dimensions ranged between 3.14 and 3.79 mm in diameter and 0.20 and 0.47 mm in depth. Tissue perforation was not observed. To test the potential for radiofrequency fusion of intimal tears, 5 atm of pressure and 200 J radiofrequency energy were delivered from block-mounted bipolar electrodes to 48 segments of human atherosclerotic aorta, which had been manually separated into intima-media and media-adventitial layers. Significantly stronger tissue fusion resulted (28.5 +/- 3.3 g) with radiofrequency compared with that with pressure alone (4.8 +/- 0.26 g; p less than 0.0001). A prototype radiofrequency balloon catheter was used to deliver 3 atm of balloon pressure with or without 200 J radiofrequency energy to 20 postmortem human atherosclerotic arterial segments. In 10 of 10 radiofrequency-treated vessels, thermal "molding" of both normal and atherosclerotic vessel wall segments resulted with increased luminal diameter and histologic evidence of medial myocyte damage.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Catheter Ablation for Ventricular Tachycardia in Patients with Nonischemic Cardiomyopathy.

    PubMed

    Thompson, Nathaniel; Frontera, Antonio; Takigawa, Masateru; Cheniti, Ghassen; Massoullie, Gregoire; Cochet, Hubert; Denis, Arnaud; Chaumeil, Arnaud; Derval, Nicolas; Hocini, Meleze; Haissaguerre, Michel; Jais, Pierre; Sacher, Frederic

    2017-03-01

    Although catheter ablation has been successful in reducing the recurrence of ventricular tachycardia in patients with ischemic disease, outcomes in patients with nonischemic cardiomyopathy (NICM) have not met with the same results. Success is predicated on a methodical approach to diagnosis of disease type and identification of critical substrate, and the ablation strategies used. Cardiac MRI with delayed enhancement is able to identify areas of substrate involvement, particularly in situations when conventional catheter mapping is not able to do so. Radiofrequency needle, irrigated bipolar radiofrequency, and transcoronary alcohol ablation are effective and alternative techniques to endocardial and epicardial ablation. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. An Update on the Energy Sources and Catheter Technology for the Ablation of Atrial Fibrillation.

    PubMed

    Arora, Pawan K; Hansen, James C; Price, Adam D; Koblish, Josef; Avitall, Boaz

    2010-01-01

    The ablation of atrial fibrillation (AF) is an area of intense research in cardiac electrophysiology. In this review, we discuss the development of catheter-based interventions for AF ablation. We outline the pathophysiologic and anatomic bases for ablative lesion sets and the evolution of various catheter designs for the delivery of radiofrequency (RF), cryothermal, and other ablative energy sources. The strengths and weaknesses of various specialized RF catheters and alternative energy systems are delineated, with respect to efficacy and patient safety.

  3. Biophysics and pathology of catheter energy delivery systems.

    PubMed

    Nath, S; Haines, D E

    1995-01-01

    Catheter ablation has rapidly emerged as the treatment of choice for many symptomatic cardiac arrhythmias. The initial experience with catheter ablation used high-energy DC as the energy source. However, over the last several years radiofrequency (RF) catheter ablation has become the dominant mode of energy delivery. Currently, a major limitation of RF ablation is the small lesion size created by this technique that has reduced its success rate in ablation of larger arrhythmogenic substrates such as coronary artery disease-related ventricular tachycardia. Alternate energy sources such as microwave or ultrasound catheter ablation are being developed that have the potential for producing larger lesions than RF ablation. This review will discuss the biophysics and pathophysiology of the various energy modalities used in catheter ablation.

  4. Radiofrequency Ablation of Liver Tumors

    MedlinePlus

    ... Other equipment such as needle electrodes, an electrical generator and grounding pads may also be used. Radiofrequency ... retractable electrodes that extend when needed. The radiofrequency generator produces electrical currents in the range of radiofrequency ...

  5. Hemodialysis Tunneled Catheter Noninfectious Complications

    PubMed Central

    Miller, Lisa M.; MacRae, Jennifer M.; Kiaii, Mercedeh; Clark, Edward; Dipchand, Christine; Kappel, Joanne; Lok, Charmaine; Luscombe, Rick; Moist, Louise; Oliver, Matthew; Pike, Pamela; Hiremath, Swapnil

    2016-01-01

    Noninfectious hemodialysis catheter complications include catheter dysfunction, catheter-related thrombus, and central vein stenosis. The definitions, causes, and treatment strategies for catheter dysfunction are reviewed below. Catheter-related thrombus is a less common but serious complication of catheters, requiring catheter removal and systemic anticoagulation. In addition, the risk factors, clinical manifestation, and treatment options for central vein stenosis are outlined. PMID:28270922

  6. Radiofrequency ablation of fast ventricular tachycardia causing an ICD storm in an infant with hypertrophic cardiomyopathy.

    PubMed

    Ergul, Yakup; Ozyilmaz, Isa; Bilici, Meki; Ozturk, Erkut; Haydin, Sertaç; Guzeltas, Alper

    2017-07-27

    An implantable cardioverter defibrillator (ICD) storm involves very frequent arrhythmia episodes and ICD shocks, and it is associated with poor short-term and long-term prognosis. Radiofrequency catheter ablation can be used as an effective rescue treatment for patients with an ICD storm. To our knowledge, this is the first report of an infant with hypertrophic cardiomyopathy presenting with an ICD storm and undergoing successful radiofrequency catheter ablation salvage treatment for the fast left posterior fascicular ventricular tachycardia. © 2017 Wiley Periodicals, Inc.

  7. Catheter-Associated Infections

    PubMed Central

    Trautner, Barbara W.; Darouiche, Rabih O.

    2010-01-01

    Intravascular catheters and urinary catheters are the 2 most commonly inserted medical devices in the United States, and they are likewise the two most common causes of nosocomially acquired bloodstream infection. Biofilm formation on the surfaces of indwelling catheters is central to the pathogenesis of infection of both types of catheters. The cornerstone to any preventive strategy of intravascular catheter infections is strict attention to infection control practices. Antimicrobial-impregnated intravascular catheters are a useful adjunction to infection control measures. Prevention of urinary catheter–associated infection is hindered by the numbers and types of organisms present in the periurethral area as well as by the typically longer duration of catheter placement. Antimicrobial agents in general have not been effective in preventing catheter-associated urinary tract infection in persons with long-term, indwelling urethral catheters. Preventive strategies that avoid the use of antimicrobial agents may be necessary in this population. PMID:15111369

  8. Advances in irrigated tip catheter technology for treatment of cardiac arrhythmias.

    PubMed

    Peichl, Petr; Kautzner, Josef

    2013-04-01

    Radiofrequency catheter ablation without active cooling of the catheter tip is associated with significantly increased risk of thrombus formation and thromboembolism, especially when multiple and high-energy deliveries are considered. Therefore, irrigation of the distal electrode has become obligatory for catheter ablation of complex cardiac arrhythmias. The advancement in the cooling catheter technology is aimed to further reduce the risk of steam pop as well as coagulum formation on both electrode and tissue, and to maximize energy transfer to the tissue. Whether novel catheter designs will translate into better success rates of catheter ablation and lower risk of complications remains to be evaluated by upcoming studies. In future, a combination with novel sensors that enable online monitoring of lesion creation is expected. Such technology should allow optimization of radiofrequency delivery without risk of deep tissue overheating and steam pop creation. Recent patents in the field of irrigated ablation catheter focus mainly on novel porous materials that would enable diffuse irrigation around the catheter tip and alternative layout of irrigation holes. Additionally, some patents deal with combination of irrigation fluid tubing and different sensors located within the catheter tip.

  9. Mapping and ablation of ventricular arrhythmias with magnetic navigation: comparison between 4- and 8-mm catheter tips.

    PubMed

    Di Biase, Luigi; Burkhardt, J David; Lakkireddy, Dhanunjaya; Pillarisetti, Jayasree; Baryun, Esam Nuri; Biria, Mazda; Horton, Rodney; Sanchez, Javier; Gallinghouse, G Joseph; Bailey, Shane; Beheiry, Salwa; Hongo, Richard; Hao, Steven; Tomassoni, Gery; Natale, Andrea

    2009-11-01

    Remote magnetic navigation (RMN) has been reported as an effective and safe tool to overcome the need for advanced operator skill in the treatment of complex arrhythmias. We report a series of patients undergoing radiofrequency catheter ablation of ventricular arrhythmias (VAs) using RMN with either a 4-mm catheter tip or an 8-mm catheter tip at four different centers. Sixty-five patients with clinical and symptomatic history of Vas were included. Two different magnetic catheters were used to deliver radiofrequency applications remotely. When ablation with the RMN catheters failed, a manual irrigated catheter was used to eliminate the VAs. Post-ablation pacing maneuvers were utilized to verify the inducibility of Vas. Twenty-eight patients (43%) had ischemic cardiomyopathy [coronary artery disease (CAD)], 16 patients (25%) had non-ischemic cardiomyopathy [idiopathic dilated cardiomyopathy (IDC)], and 21 patients (32%) had structurally normal hearts (SNH) or right ventricle outflow tract tachycardia (RVOT). In patients with structural heart disease (CAD, IDC), success was achieved in 22% with the 4-mm catheter tip and in 59% with the 8-mm catheter tip (p = 0.014). In patients with SNH/RVOT, success was achieved in 85% with the 4-mm catheter tip and in 87% with the 8-mm catheter tip (p = 1.00). Our findings showed that, with RMN, there is an increased success related to the catheter tip utilized. However, in patients with right ventricular outflow origin, the standard 4-mm tip provided adequate lesions for successful ablation in most patients.

  10. Effects of multipolar electrode radiofrequency energy delivery on ventricular endocardium

    SciTech Connect

    Oeff, M.; Langberg, J.J.; Franklin, J.O.; Chin, M.C.; Sharkey, H.; Finkbeiner, W.; Herre, J.M.; Scheinman, M.M. )

    1990-03-01

    This study examined the effects of radiofrequency energy applied in a bipolar fashion with single as compared with multiple sequential applications at the canine endocardium. In this closed-chest model, radiofrequency energy (750 kHz) was delivered between two adjacent poles of an electrode catheter. Single applications were performed at distinct sites in the left (n = 30) and right ventricles (n = 29) of 13 normal dogs. A multiple sequential technique, which enlarges the ablated endocardial surface, was applied in the left (n = 13) and right ventricles (n = 4) of seven normal dogs and six dogs with remote myocardial infarction. Single applications (199 +/- 200 joules) resulted in lesions with a volume of 0.12 +/- 0.06 cm3 (range 0.03 to 0.31 cm3) and an endocardial surface area of 0.29 +/- 0.15 cm2 (range 0.06 to 0.63 cm2). Changes at the catheter/tissue interface led to a rise in impedance, restricting further enlargement of the necrosis. Sequential delivery of radiofrequency energy between poles 1 and 2, 2 and 3, and 3 and 4 of a quadripolar electrode catheter repeated 9 to 11 times in slightly different positions allowed a cumulative energy of 6571 +/- 3857 joules to be applied to the endocardium, resulting in a lesion volume of 0.84 +/- 0.38 cm3, with an endocardial lesion surface area of 3.7 +/- 1.2 cm2 (range 2.9 to 5.1 cm2). Histologically, all radiofrequency lesions were restricted to the endocardium/subendocardium with a small border zone of injury. Aggressive stimulation techniques did not induce ventricular tachycardia in any of the dogs before and 19 +/- 11.4 days after multiple sequential ablations.

  11. 21 CFR 876.5130 - Urological catheter and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... generic type of device includes radiopaque urological catheters, ureteral catheters, urethral catheters, coude catheters, balloon retention type catheters, straight catheters, upper urinary tract...

  12. 21 CFR 876.5130 - Urological catheter and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... generic type of device includes radiopaque urological catheters, ureteral catheters, urethral catheters, coudé catheters, balloon retention type catheters, straight catheters, upper urinary tract...

  13. 21 CFR 876.5130 - Urological catheter and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... generic type of device includes radiopaque urological catheters, ureteral catheters, urethral catheters, coudé catheters, balloon retention type catheters, straight catheters, upper urinary tract...

  14. Steerable catheter microcoils for interventional MRI reducing resistive heating.

    PubMed

    Bernhardt, Anthony; Wilson, Mark W; Settecase, Fabio; Evans, Leland; Malba, Vincent; Martin, Alastair J; Saeed, Maythem; Roberts, Timothy P L; Arenson, Ronald L; Hetts, Steven W

    2011-03-01

    The aims of this study were to assess resistive heating of microwires used for remote catheter steering in interventional magnetic resonance imaging and to investigate the use of alumina to facilitate heat transfer to saline flowing in the catheter lumen. A microcoil was fabricated using a laser lathe onto polyimide-tipped or alumina-tipped endovascular catheters. In vitro testing was performed on a 1.5-T magnetic resonance system using a vessel phantom, body radiofrequency coil, and steady-state pulse sequence. Resistive heating was measured with water flowing over a polyimide-tip catheter or saline flowing through the lumen of an alumina-tip catheter. Preliminary in vivo testing in porcine common carotid arteries was conducted with normal blood flow or after arterial ligation when current was applied to an alumina-tip catheter for up to 5 minutes. After application of up to 1 W of direct current power, clinically significant temperature increases were noted with the polyimide-tip catheter: 23°C/W at zero flow, 13°C/W at 0.28 cm(3)/s, and 7.9°C/W at 1 cm(3)/s. Using the alumina-tip catheter, the effluent temperature rise using the lowest flow rate (0.12 cm(3)/s) was 2.3°C/W. In vivo testing demonstrated no thermal injury to vessel walls at normal and zero arterial flow. Resistive heating in current carrying wire pairs can be dissipated by saline coolant flowing within the lumen of a catheter tip composed of material that facilitates heat transfer. Copyright © 2011 AUR. Published by Elsevier Inc. All rights reserved.

  15. Novel Percutaneous Radiofrequency Ablation of Portal Vein Tumor Thrombus: Safety and Feasibility

    SciTech Connect

    Mizandari, Malkhaz; Ao, Guokun; Zhang Yaojun; Feng Xi; Shen Qiang; Chen Minshan; Lau, Wan Yee; Nicholls, Joanna; Jiao Long; Habib, Nagy

    2013-02-15

    We report our experience of the safety of partial recanalization of the portal vein using a novel endovascular radiofrequency (RF) catheter for portal vein tumor thrombosis. Six patients with liver cancer and tumor thrombus in the portal vein underwent percutaneous intravascular radiofrequency ablation (RFA) using an endovascular bipolar RF device. A 0.035-inch guidewire was introduced into a tributary of the portal vein and through which a 5G guide catheter was introduced into the main portal vein. After manipulation of the guide catheter over the thrombus under digital subtraction angiography, the endovascular RF device was inserted and activated around the thrombus. There were no observed technique specific complications, such as hemorrhage, vessel perforation, or infection. Post-RFA portography showed partial recanalization of portal vein. RFA of portal vein tumor thrombus in patients with hepatocellular carcinoma is technically feasible and warrants further investigation to assess efficacy compared with current recanalization techniques.

  16. Insights into energy delivery to myocardial tissue during radiofrequency ablation through application of the first law of thermodynamics.

    PubMed

    Bunch, T Jared; Day, John D; Packer, Douglas L

    2009-04-01

    The approach to catheter-based radiofrequency ablation of atrial fibrillation has evolved, and as a consequence, more energy is delivered in the posterior left atrium, exposing neighboring tissue to untoward thermal injury. Simultaneously, catheter technology has advanced to allow more efficient energy delivery into the myocardium, which compounds the likelihood of collateral injury. This review focuses on the basic principles of thermodynamics as they apply to energy delivery during radiofrequency ablation. These principles can be used to titrate energy delivery and plan ablative approaches in an effort to minimize complications during the procedure.

  17. L1 (English) to L2 (French) Transfer: The Question of Nasalization

    ERIC Educational Resources Information Center

    Garrott, Carl L.

    2006-01-01

    The purpose of this investigation was to answer the following questions: (1) Do transfer and developmental errors decrease or increase during informal and formal tasks? (2) What nasal vowels present greater markedness for L2 French learners? and (3) Using recall as the dependent variable, will French nasals continue to be produced over a time…

  18. The Development of Complexity, Accuracy and Fluency in the Written Production of L2 French

    ERIC Educational Resources Information Center

    Gunnarsson, Cecilia

    2012-01-01

    The present longitudinal case study investigated the development of fluency, complexity and accuracy--and the possible relationships between them--in the written production of L2 French. We assessed fluency and complexity in five intermediate learners by means of conventional indicators for written L2 (cf. Wolfe-Quintero et al. 1998), while…

  19. Cryo-balloon catheter localization in fluoroscopic images

    NASA Astrophysics Data System (ADS)

    Kurzendorfer, Tanja; Brost, Alexander; Jakob, Carolin; Mewes, Philip W.; Bourier, Felix; Koch, Martin; Kurzidim, Klaus; Hornegger, Joachim; Strobel, Norbert

    2013-03-01

    Minimally invasive catheter ablation has become the preferred treatment option for atrial fibrillation. Although the standard ablation procedure involves ablation points set by radio-frequency catheters, cryo-balloon catheters have even been reported to be more advantageous in certain cases. As electro-anatomical mapping systems do not support cryo-balloon ablation procedures, X-ray guidance is needed. However, current methods to provide support for cryo-balloon catheters in fluoroscopically guided ablation procedures rely heavily on manual user interaction. To improve this, we propose a first method for automatic cryo-balloon catheter localization in fluoroscopic images based on a blob detection algorithm. Our method is evaluated on 24 clinical images from 17 patients. The method successfully detected the cryoballoon in 22 out of 24 images, yielding a success rate of 91.6 %. The successful localization achieved an accuracy of 1.00 mm +/- 0.44 mm. Even though our methods currently fails in 8.4 % of the images available, it still offers a significant improvement over manual methods. Furthermore, detecting a landmark point along the cryo-balloon catheter can be a very important step for additional post-processing operations.

  20. Central venous catheters - ports

    MedlinePlus

    ... of Intravascular Catheter-Related Infections. Centers For Disease Control and Prevention. April 2011. ... MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine, Atlanta, GA. ...

  1. Assessment of reused catheters.

    PubMed

    Mussivand, T; Duguay, D G; Valadares, M J; Rajagopalan, K; Mackenzie, A M; Blohon, R; Marquis, J F; Beanlands, D S; Keon, W J

    1995-01-01

    Demands for health care cost containment have prompted the assessment of recycling medical devices, including catheters. The investigation of catheter reuse for effectiveness and safety began at the University of Ottawa Heart Institute in early 1994. This report provides the preliminary results from this ongoing assessment on the feasibility of catheter reuse. Burst tests were conducted to detect changes in catheter mechanical integrity. Scanning electron microscopy (SEM) was performed to assess surface changes and protein deposition after use and the subsequent cleaning process. Results of burst testing showed no significant difference in burst patterns or burst pressures between single use and unused catheters. Surface differences were observed between used and unused catheters. SEM studies detected physical changes such as scratches, gouges, cuts, and deposits on the used catheters. Unused balloon surfaces appeared to be clean and uniform compared to used ones. Residue and cracking were identified on other used devices. In conclusion, the methods used can assess various effects of recycling. A blind study of large samples of used catheters is planned to establish statistically the level and variance of structural damage to catheters during typical use.

  2. The Growth of Complexity and Accuracy in L2 French: Past Observations and Recent Applications of Developmental Stages

    ERIC Educational Resources Information Center

    Agren, Malin; Granfeldt, Jonas; Schlyter, Suzanne

    2012-01-01

    This chapter addresses the question of the growth of accuracy and complexity in L2 French from the perspective of developmental sequences of morphosyntax, developmental stages and linguistic profiling. The six developmental stages for L2 French proposed by Bartning and Schlyter (2004) are presented and exemplified and new results are added to the…

  3. The Growth of Complexity and Accuracy in L2 French: Past Observations and Recent Applications of Developmental Stages

    ERIC Educational Resources Information Center

    Agren, Malin; Granfeldt, Jonas; Schlyter, Suzanne

    2012-01-01

    This chapter addresses the question of the growth of accuracy and complexity in L2 French from the perspective of developmental sequences of morphosyntax, developmental stages and linguistic profiling. The six developmental stages for L2 French proposed by Bartning and Schlyter (2004) are presented and exemplified and new results are added to the…

  4. [The bladder catheter].

    PubMed

    Pestalozzi, D M

    1996-09-01

    The benefit of the transurethral catheter to protect or measure renal function is well accepted. Urethral stricture and infection of the lower urinary tract as the complications should lead to a cautious use of catheters. A careful placement, the choice of the best material and a correct management help to avoid complications. Alternatives are discussed.

  5. [Current treatment of Wolff-Parkinson-White syndrome and ventricular tachycardia: surgical ablation versus catheter ablation?].

    PubMed

    Misaki, T; Watanabe, G; Iwa, T; Watanabe, Y

    1992-09-01

    From November 1973, 454 patients with Wolff-Parkinson-White syndrome underwent surgical ablation of accessory pathways. Overall curative rate was 94% in our series including 65 cases of simultaneous surgical repair for combined heart diseases. In recent months, radiofrequency catheter ablation was applied in 7 cases. There has been 2 failures, which have taken more than 2 hours of radiation exposure and have required surgery. There has been 47 patients who underwent surgical ablation for non-ischemic ventricular tachycardia. Forty cases (85%) had a successful outcome of surgical ablation and another 2 cases required DC catheter ablation postoperatively to eliminate ventricular tachycardias. In conclusion, radiofrequency ablation of WPW syndrome in patients without combined heart disease or multiple accessory pathways is feasible. Surgical ablation is effective and safe technique compared with catheter ablation in patients with ventricular tachycardia.

  6. A simple and safe technique for positioning a bipolar radio-frequency device for pulmonary vein isolation.

    PubMed

    Shimamura, Yoshiei; Hayashi, Ichiro

    2009-08-01

    We describe a simple and safe technique to position a bipolar radio-frequency ablation device around the pulmonary veins when performing pulmonary vein isolation. The technique consists of insertion of a rubber catheter with stylet, originally an introducer from a left vent catheter, behind the pulmonary veins, and subsequent placement of the lower jaw of the ablation clamp using a rubber catheter to guide the device into position. This novel method avoids excessive compression or displacement of the heart and enables easy and safe positioning of the ablation device around the pulmonary veins.

  7. Cryoablation Versus Radiofrequency Ablation in AVNRT: Same Goal, Different Strategy.

    PubMed

    Leila, Riahi; Raluca, Prisecaru; Yves, De Greef; Dirk, Stockman; Bruno, Schwagten

    2015-01-01

    Catheter ablation is nowadays the first therapeutic option for AVNRT, the most common benign supraventricular tachycardia. Both cryotherapy and radiofrequency energy may be used to ablate the slow pathway. This paper compares both techniques, evaluates results published in literature and gives feedback on some typical aspects of cryo- and RF ablation. Although both techniques have satisfying success rates in AVNRT ablation, with a higher safety profile of cryoablation towards creation of inadvertent atrioventricular block, it remains paramount that the operator respects the distinctive traits of each technique in order to obtain an optimal result in every patient.

  8. Radiofrequency Ablation of Cancer

    SciTech Connect

    Friedman, Marc; Mikityansky, Igor; Kam, Anthony; Libutti, Steven K.; Walther, McClellan M.; Neeman, Ziv; Locklin, Julia K.; Wood, Bradford J.

    2004-09-15

    Radiofrequency ablation (RFA) has been used for over 18 years for treatment of nerve-related chronic pain and cardiac arrhythmias. In the last 10 years, technical developments have increased ablation volumes in a controllable, versatile, and relatively inexpensive manner. The host of clinical applications for RFA have similarly expanded. Current RFA equipment, techniques, applications, results, complications, and research avenues for local tumor ablation are summarized.

  9. Radiofrequency Ablation of Cancer

    PubMed Central

    Friedman, Marc; Mikityansky, Igor; Kam, Anthony; Libutti, Steven K.; Walther, McClellan M.; Neeman, Ziv; Locklin, Julia K.; Wood, Bradford J.

    2008-01-01

    Radiofrequency ablation (RFA) has been used for over 18 years for treatment of nerve-related chronic pain and cardiac arrhythmias. In the last 10 years, technical developments have increased ablation volumes in a controllable, versatile, and relatively inexpensive manner. The host of clinical applications for RFA have similarly expanded. Current RFA equipment, techniques, applications, results, complications, and research avenues for local tumor ablation are summarized. PMID:15383844

  10. Suprapubic catheter care

    MedlinePlus

    ... urine bag only a few times a day. Caring for Your Skin Near your Catheter Follow these ... Bethesda, MD 20894 U.S. Department of Health and Human Services National Institutes of Health Page last updated: ...

  11. Sinuplasty (Balloon Catheter Dilation)

    MedlinePlus

    ... development of the balloon dilating catheter and its adaptation to sinus surgery. In the 1980s, the field ... used in endoscopic sinus surgery. It is the adaptation or application of minimally-invasive balloon technology to ...

  12. Indwelling catheter care

    MedlinePlus

    ... skin care part of your daily routine. Avoid physical activity for a week or two after your catheter is placed in your bladder. Cleaning Your Skin You will need these supplies for cleaning your ...

  13. Central venous catheter - flushing

    MedlinePlus

    ... To flush your catheter, you will need: Clean paper towels Saline syringes (clear), and maybe heparin syringes (yellow) ... your fingers before washing. Dry with a clean paper towel. Set up your supplies on a clean surface ...

  14. MR-Guided Percutaneous Angioplasty: Assessment of Tracking Safety, Catheter Handling and Functionality

    SciTech Connect

    Wildermuth, Simon; Dumoulin, Charles L.; Pfammatter, Thomas; Maier, Stephan E.; Hofmann, Eugen; Debatin, Joerg F.

    1998-09-15

    Purpose: Magnetic resonance (MR)-guided percutaneous vascular interventions have evolved to a practical possibility with the advent of open-configuration MR systems and real-time tracking techniques. The purpose of this study was to assess an MR-tracking percutaneous transluminal angioplasty (PTA) catheter with regard to its safety profile and functionality. Methods: Real-time, biplanar tracking of the PTA catheter was made possible by incorporating a small radiofrequency (RF) coil in the catheter tip and connecting it to a coaxial cable embedded in the catheter wall. To evaluate potentially hazardous thermal effects due to the incorporation of the coil, temperature measurements were performed within and around the coil under various scanning and tracking conditions at 1.5 Tesla (T). Catheter force transmission and balloon-burst pressure of the MR-tracking PTA catheter were compared with those of a standard PTA catheter. The dilatative capability of the angioplasty balloon was assessed in vitro as well as in vivo, in an isolated femoral artery segment in a swine. Results: The degree of heating at the RF coil was directly proportional to the power of the RF pulses. Heating was negligible with MR tracking, conventional spin-echo and low-flip gradient-echo sequences. Sequences with higher duty cycles, such as fast spin echo, produced harmful heating effects. Force transmission of the MR-tracking PTA catheter was slightly inferior to that of the standard PTA catheter, while balloon-burst pressures were similar to those of conventional catheters. The MR-tracking PTA catheter functioned well both in vitro and in vivo. Conclusion: The in vivo use of an MR-tracking PTA catheter is safe under most scanning conditions.

  15. Cryo-balloon catheter position planning using AFiT

    NASA Astrophysics Data System (ADS)

    Kleinoeder, Andreas; Brost, Alexander; Bourier, Felix; Koch, Martin; Kurzidim, Klaus; Hornegger, Joachim; Strobel, Norbert

    2012-02-01

    Atrial fibrillation (AFib) is the most common heart arrhythmia. In certain situations, it can result in life-threatening complications such as stroke and heart failure. For paroxsysmal AFib, pulmonary vein isolation (PVI) by catheter ablation is the recommended choice of treatment if drug therapy fails. During minimally invasive procedures, electrically active tissue around the pulmonary veins is destroyed by either applying heat or cryothermal energy to the tissue. The procedure is usually performed in electrophysiology labs under fluoroscopic guidance. Besides radio-frequency catheter ablation devices, so-called single-shot devices, e.g., the cryothermal balloon catheters, are receiving more and more interest in the electrophysiology (EP) community. Single-shot devices may be advantageous for certain cases, since they can simplify the creation of contiguous (gapless) lesion sets around the pulmonary vein which is needed to achieve PVI. In many cases, a 3-D (CT, MRI, or C-arm CT) image of a patient's left atrium is available. This data can then be used for planning purposes and for supporting catheter navigation during the procedure. Cryo-thermal balloon catheters are commercially available in two different sizes. We propose the Atrial Fibrillation Planning Tool (AFiT), which visualizes the segmented left atrium as well as multiple cryo-balloon catheters within a virtual reality, to find out how well cryo-balloons fit to the anatomy of a patient's left atrium. First evaluations have shown that AFiT helps physicians in two ways. First, they can better assess whether cryoballoon ablation or RF ablation is the treatment of choice at all. Second, they can select the proper-size cryo-balloon catheter with more confidence.

  16. [Urinary catheter biofilm infections].

    PubMed

    Holá, V; Růzicka, F

    2008-04-01

    Urinary tract infections, most of which are biofilm infections in catheterized patients, account for more than 40% of hospital infections. Bacterial colonization of the urinary tract and catheters causes not only infection but also other complications such as catheter blockage by bacterial encrustation, urolithiasis and pyelonephritis. About 50% of long-term catheterized patients face urinary flow obstruction due to catheter encrustation, but no measure is currently available to prevent it. Encrustation has been known either to result from metabolic dysfunction or to be of microbial origin, with urease positive bacterial species implicated most often. Infectious calculi account for about 15-20% of all cases of urolithiasis and are often associated with biofilm colonization of a long-term indwelling urinary catheter or urethral stent. The use of closed catheter systems is helpful in reducing such problems; nevertheless, such a system only delays the inevitable, with infections emerging a little later. Various coatings intended to prevent the bacterial adhesion to the surface of catheters and implants and thus also the emergence of biofilm infections, unfortunately, do not inhibit the microbial adhesion completely and permanently and the only reliable method for biofilm eradication remains the removal of the foreign body from the patient.

  17. Optimization of the generator settings for endobiliary radiofrequency ablation.

    PubMed

    Barret, Maximilien; Leblanc, Sarah; Vienne, Ariane; Rouquette, Alexandre; Beuvon, Frederic; Chaussade, Stanislas; Prat, Frederic

    2015-11-10

    To determine the optimal generator settings for endobiliary radiofrequency ablation. Endobiliary radiofrequency ablation was performed in live swine on the ampulla of Vater, the common bile duct and in the hepatic parenchyma. Radiofrequency ablation time, "effect", and power were allowed to vary. The animals were sacrificed two hours after the procedure. Histopathological assessment of the depth of the thermal lesions was performed. Twenty-five radiofrequency bursts were applied in three swine. In the ampulla of Vater (n = 3), necrosis of the duodenal wall was observed starting with an effect set at 8, power output set at 10 W, and a 30 s shot duration, whereas superficial mucosal damage of up to 350 μm in depth was recorded for an effect set at 8, power output set at 6 W and a 30 s shot duration. In the common bile duct (n = 4), a 1070 μm, safe and efficient ablation was obtained for an effect set at 8, a power output of 8 W, and an ablation time of 30 s. Within the hepatic parenchyma (n = 18), the depth of tissue damage varied from 1620 μm (effect = 8, power = 10 W, ablation time = 15 s) to 4480 μm (effect = 8, power = 8 W, ablation time = 90 s). The duration of the catheter application appeared to be the most important parameter influencing the depth of the thermal injury during endobiliary radiofrequency ablation. In healthy swine, the currently recommended settings of the generator may induce severe, supratherapeutic tissue damage in the biliary tree, especially in the high-risk area of the ampulla of Vater.

  18. Paroxysmal atrial fibrillation ablation: Achieving permanent pulmonary vein isolation by point-by-point radiofrequency lesions

    PubMed Central

    Pedrote, Alonso; Acosta, Juan; Jáuregui-Garrido, Beatriz; Frutos-López, Manuel; Arana-Rueda, Eduardo

    2017-01-01

    Pulmonary vein isolation by point-by-point radiofrequency catheter ablation constitutes the cornerstone of catheter ablation strategies for the treatment of atrial fibrillation. However, despite advances in pulmonary vein isolation ablation strategies, long-term success rates after ablation remain suboptimal, which highlights the need to develop techniques to achieve more durable lesions. Strategies proposed to improve the durability of pulmonary vein isolation can be divided into two groups: Those addressed to improving the quality of the lesion and those that optimize the detection of acute PV reconnection during the ablation procedure. This manuscript reviews the role and potential benefits of these techniques according to current clinical evidence. PMID:28400919

  19. Peritoneal catheters and related infections.

    PubMed

    Thodis, Elias; Passadakis, Ploumis; Lyrantzopooulos, Nikolaos; Panagoutsos, Stelios; Vargemezis, Vassilis; Oreopoulos, Dimitrios

    2005-01-01

    Catheter related infectious complications (exit-site infections, tunnel infections, and peritonitis) remain the major reasons for technique failure during the three decades since, continuous ambulatory peritoneal dialysis (CAPD) treatment has been first established. Despite improvements in catheter's survival rates, catheter related complications result in an increase in the cumulative patients' morbidity and often leading to the catheter removal. The ideal catheter provides reliable and rapid dialysate flow rates without leaks or infections. Among several types, the double-cuff straight Tenckhoff catheter, developed in 1968, is still the most widely used, although its use is decreasing in favour of swanneck catheters. Although there are only few well-designed trials comparing catheters and catheters related infectious complications, controlling for all other important variables, no difference in these complications among the main types of catheters was seen. The single cuff catheters have been associated with a shorter survival rate and time to the first peritonitis episode than the double-cuff catheters. Also exit-site infections were found to be more frequent and significantly more resistant to treatment with single-cuff compared to double-cuff ones. Finally, better results have been reported with the latest developed presternal peritoneal dialysis catheter both regarding survival rates and exit-site infection and peritonitis rates. Recently a renewed interest in continuous flow peritoneal dialysis stimulated inventions of imaginative, double-lumen catheters since a suitable peritoneal access is a sine qua non condition for the development of this new technique of peritoneal dialysis.

  20. Comparison of microbubble presence in the right heart during mechanochemical and radiofrequency ablation for varicose veins.

    PubMed

    Moon, K H; Dharmarajah, B; Bootun, R; Lim, C S; Lane, Tra; Moore, H M; Sritharan, K; Davies, A H

    2017-07-01

    Objective Mechanochemical ablation is a novel technique for ablation of varicose veins utilising a rotating catheter and liquid sclerosant. Mechanochemical ablation and radiofrequency ablation have no reported neurological side-effect but the rotating mechanism of mechanochemical ablation may produce microbubbles. Air emboli have been implicated as a cause of cerebrovascular events during ultrasound-guided foam sclerotherapy and microbubbles in the heart during ultrasound-guided foam sclerotherapy have been demonstrated. This study investigated the presence of microbubbles in the right heart during varicose vein ablation by mechanochemical abaltion and radiofrequency abaltion. Methods Patients undergoing great saphenous vein ablation by mechanochemical abaltion or radiofrequency ablation were recruited. During the ablative procedure, the presence of microbubbles was assessed using transthoracic echocardiogram. Offline blinded image quantification was performed using International Consensus Criteria grading guidelines. Results From 32 recruited patients, 28 data sets were analysed. Eleven underwent mechanochemical abaltion and 17 underwent radiofrequency abaltion. There were no neurological complications. In total, 39% (11/28) of patients had grade 1 or 2 microbubbles detected. Thirty-six percent (4/11) of mechanochemical abaltion patients and 29% (5/17) of radiofrequency ablation patients had microbubbles with no significant difference between the groups ( p=0.8065). Conclusion A comparable prevalence of microbubbles between mechanochemical abaltion and radiofrequency ablation both of which are lower than that previously reported for ultrasound-guided foam sclerotherapy suggests that mechanochemical abaltion may not confer the same risk of neurological events as ultrasound-guided foam sclerotherapy for treatment of varicose veins.

  1. Epicardial catheter ablation of ventricular tachycardia in no entry left ventricle: mechanical aortic and mitral valves.

    PubMed

    Soejima, Kyoko; Nogami, Akihiko; Sekiguchi, Yukio; Harada, Tomoo; Satomi, Kazuhiro; Hirose, Takeshi; Ueda, Akiko; Miwa, Yousuke; Sato, Toshiaki; Nishio, Satoru; Shirai, Yasuhiro; Kowase, Shinya; Murakoshi, Nobuyuki; Kunugi, Shinobu; Murata, Hiroshige; Nitta, Takashi; Aonuma, Kazutaka; Yoshino, Hideaki

    2015-04-01

    In patients with mechanical aortic and mitral valves and left ventricular tachycardia, catheter ablation may be prevented by limited access to the left ventricle. In our series of 6 patients, 2 patients underwent direct surgical ablation and 4 underwent epicardial catheter ablation via a pericardial window. All patients had abnormal low voltage areas with fractionated or delayed isolated potentials on the apical epicardium. Most of the ventricular tachycardias were targeted by pace mapping. Sites with a good pace match or abnormal electrograms were ablated using an irrigated radiofrequency ablation catheter. A microscopic pathological evaluation of the resected tissue from 2 of the open-heart ablation patients revealed dense fibrosis on the epicardium compared with the endocardium, supporting the feasibility of an epicardial ablation for the ventricular tachycardia. Epicardial catheter ablation of ventricular tachycardia is a potentially useful therapy in patients who have mechanical aortic and mitral valves. © 2015 American Heart Association, Inc.

  2. RF transmit power limit for the barewire loopless catheter antenna.

    PubMed

    Yeung, C J; Atalar, E

    2000-07-01

    The safety of the barewire loopless catheter antenna in transmit mode is addressed with respect to radiofrequency (RF) heating. Analytical expressions for electric field and specific absorption rate (SAR) distributions surrounding the antenna are postulated and experimentally verified. Limiting RF transmit power to 40-70 mW time-averaged power, depending on the specific antenna design, will ensure that the current regulatory guideline of SAR of 8 W/kg in any gram of tissue is not exceeded. These limits can act as guidelines for the design of RF pulses for use with this device. Further study is required to examine the safety of the antenna in receive mode.

  3. Development of a Novel Shock Wave Catheter Ablation System

    NASA Astrophysics Data System (ADS)

    Yamamoto, H.; Hasebe, Yuhi; Kondo, Masateru; Fukuda, Koji; Takayama, Kazuyoshi; Shimokawa, Hiroaki

    Although radio-frequency catheter ablation (RFCA) is quite effective for the treatment tachyarrhythmias, it possesses two fundamental limitations, including limited efficacy for the treatment of ventricular tachyarrhythmias of epicardial origin and the risk of thromboembolism. Consequently, new method is required, which can eradicate arrhythmia source in deep part of cardiac muscle without heating. On the other hand, for a medical application of shock waves, extracorporeal shock wave lithotripter (ESWL) has been established [1]. It was demonstrated that the underwater shock focusing is one of most efficient method to generate a controlled high pressure in a small region [2]. In order to overcome limitations of existing methods, we aimed to develop a new catheter ablation system with underwater shock waves that can treat myocardium at arbitrary depth without causing heat.

  4. [Patient selection for catheter ablation of atrial fibrillation].

    PubMed

    Márquez, Manlio F

    2007-01-01

    The present report describes the program of radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) in patients referred to the AF Clinic of the National Institute of Cardiology. Specific inclusion criteria are required for RFCA of AF. If the patient fulfills it, then an electrophysiological study is performed. A transseptal approach and special mapping catheters are used to detect abnormal electrical activity (AEA). Pulmonary vein isolation is performed at the ostium/ antrum of those veins with AEA if the patient had paroxysmal AF. Global pulmonary vein isolation with some additional lines guided by electroanatomical mapping is performed in the case of chronic AF. Postoperative follow-up includes consultation, ECG and Holter monitoring at 1, 3, 6 and 12-month. RFCA is a useful and relatively safe procedure for the treatment of AF and the only one with curative potential.

  5. Bladder Morphology Using 2 Different Catheter Designs

    ClinicalTrials.gov

    2017-04-10

    Urologic Injuries; Urologic Diseases; Bladder Infection; Urinary Tract Infections; Mucosal Inflammation; Mucosal Infection; Bladder Injury; Catheter-Related Infections; Catheter Complications; Catheter; Infection (Indwelling Catheter); Pelvic Floor Disorders; Urinary Incontinence

  6. [Radiofrequency treatment of tachyarrhythmias in children and adolescents].

    PubMed

    Martínez, J L; Monedero, C M; Alvaro, E M; Prado, A P; Villacastín, J P; Fernández, E J; Maíz, A A; Argüelles, J I; Garrote, J A

    1995-12-01

    Radiofrequency ablation has been extensively used in adults to treat supraventricular and ventricular tachycardia. In children and adolescents few data are available on its safety and efficacy. 28 patients (mean age 12.8) with symptomatic tachyarrhythmias underwent catheter ablation; 21 children had atrioventricular accessory pathways (11 right connections, 9 lef connections and one midseptal pathway), 3 had intranodal tachycardia, 2 had ventricular tachycardia and 2 had atrial tachycardia. Only four patients had associated structural anomalies. Success rate was 71.4% (20 patients). The success per cents in each group were: in intranodal tachycardias 100%; we failed in the two patients with ventricular tachycardias; in accessory pathways 76.1% and 50% in atrial tachycardia. There were no recurrences of arrhythmia in a mean chase period of 24 months (12-46). Major complications were only observed in one patient who developed a Wallenberg syndrome after ablation. Radiofrequency catheter ablation appears to be a safe and effective method to treat arrhythmias in children and adolescents, which in most cases can supersede surgery. Alow incidence of complications is reported, although long term damage on endocardial structures remains yet to be determined.

  7. Electrical storm in dilated cardiomyopathy treated using epicardial radiofrequency ablation as a first line therapy.

    PubMed

    Faustino, Massimiliano; Agricola, Tullio; Xyheri, Borejda; Di Girolamo, Enrico; Leonzio, Luigi; Pizzi, Carmine

    2016-09-01

    We report a patient with non-ischemic dilated cardiomyopathy and low left ventricular systolic function (28%) presenting with an electrical storm originated in epicardial scar and ablated by radiofrequency. This case report suggests that a strategy of epicardial catheter ablation is reasonable for the patient presenting with electrical storm related to structural disease with a low left ventricular ejection fraction. Copyright © 2016 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

  8. Radiofrequency Guide Wire Recanalization of Venous Occlusions in Patients with Malignant Superior Vena Cava Syndrome

    SciTech Connect

    Davis, Robert M.; David, Elizabeth; Pugash, Robyn A.; Annamalai, Ganesan

    2012-06-15

    Fibrotic central venous occlusions in patients with thoracic malignancy and prior radiotherapy can be impassable with standard catheters and wires, including the trailing or stiff end of a hydrophilic wire. We report two patients with superior vena cava syndrome in whom we successfully utilized a radiofrequency guide wire (PowerWire, Baylis Medical, Montreal, Quebec, Canada) to perforate through the occlusion and recanalize the occluded segment to alleviate symptoms.

  9. [A comparative study between surgical section and radiofrequency ablation of the anomalous pathways in the WPW syndrome].

    PubMed

    Iturralde, P; Colín, L; Kershenovich, S; Saucedo, J; de Micheli, A; Barragán, R; Martínez Rios, M A; González Hermosillo, J A

    1993-01-01

    Radiofrequency catheter ablation is an effective alternative to medical therapy to patient with Wolff Parkinson White syndrome (WPW). The purpose of this study is to compare our results in 70 patients with WPW that underwent either surgery or ablation procedure with radiofrequency energy. Of this number of patients the surgical procedure was successful in 82%; complications were present in 15% and mortality in 8%. Average hospitalization was 6 to 10 days and cost from 2 to 10 thousand of new pesos. On the other hand, of 44 patients that underwent radiofrequency ablation, in 80% the procedure was finally successful with recurrence of 9% and no mortality. The hospitalization period was one day, the cost run from 500 to 2 thousand of new pesos in our institution. These results demonstrate the efficacy of the radiofrequency energy ablation in the treatment of WPW. This procedure is safe and less expensive than surgery.

  10. Catheter-related bloodstream infections.

    PubMed

    Wilcox, Tracie A

    2009-06-01

    Tunneled, cuffed, double-lumen catheters are commonly used for long-term venous access in hemodialysis patients. Complications of these catheters, including catheter-related infection, are a major cause of morbidity and resource utilization in the hemodialysis population. Treatment of catheter-related bloodstream infections includes the use of antibiotics and evaluation of the need for catheter removal or exchange. Measures to prevent catheter-related infections include use of an aseptic technique and antiseptic cleaning solution, elimination of Staphylococcus aureus nasal carriage, topical exit site application of antibiotics, use of antibiotic lock solutions, and use of catheters and cuffs coated or impregnated with antimicrobial or antiseptic agents. This review article will provide an update on the prevalence, diagnosis, treatment, and prevention of catheter-related infections in the hemodialysis population.

  11. Balloon Catheter Prevents Contamination

    NASA Technical Reports Server (NTRS)

    Higginson, Gregory A.; Bouffard, Marc R.; Hoehicke, Beth S.; King, Bradley D.; Peterson, Sandra L.

    1994-01-01

    Balloon catheter similar to that used in such medical procedures as angioplasty and heart surgery protects small orifices against contamination and blockage by chips generated in machining operations. Includes small, inflatable balloon at end of thin, flexible tube. Contains additional features adapting it to anticontamination service: balloon larger to fit wider channel it must block; made of polyurethane (rather than latex), which does not fragment if bursts; material made thicker to resist abrasion better; and kink-resistant axial wire helps catheter negotiate tight bends.

  12. Balloon Catheter Prevents Contamination

    NASA Technical Reports Server (NTRS)

    Higginson, Gregory A.; Bouffard, Marc R.; Hoehicke, Beth S.; King, Bradley D.; Peterson, Sandra L.

    1994-01-01

    Balloon catheter similar to that used in such medical procedures as angioplasty and heart surgery protects small orifices against contamination and blockage by chips generated in machining operations. Includes small, inflatable balloon at end of thin, flexible tube. Contains additional features adapting it to anticontamination service: balloon larger to fit wider channel it must block; made of polyurethane (rather than latex), which does not fragment if bursts; material made thicker to resist abrasion better; and kink-resistant axial wire helps catheter negotiate tight bends.

  13. Catheter ablation of atrial fibrillation without the use of fluoroscopy.

    PubMed

    Reddy, Vivek Y; Morales, Gustavo; Ahmed, Humera; Neuzil, Petr; Dukkipati, Srinivas; Kim, Steve; Clemens, Janet; D'Avila, Andre

    2010-11-01

    In performing catheter ablation of paroxysmal atrial fibrillation (PAF), the advent of electroanatomical mapping (EAM) has significantly reduced fluoroscopy time. Recent advances in the ability of EAM systems to simultaneously visualize multiple catheters have allowed some operators to perform certain procedures, such as catheter ablation of supraventricular tachycardias, with zero fluoroscopy use. The purpose of this study was to evaluate the feasibility and safety of pulmonary vein (PV) isolation with zero fluoroscopy use, using a combination of three-dimensional EAM and intracardiac echocardiography (ICE). Using the NavX EAM system, the right atrial (RA) and coronary sinus (CS) geometries were created without fluoroscopy. Fluoroless transseptal puncture was performed under ICE guidance. Using a deflectable sheath and a multipolar catheter, the left atrial (LA) and PV anatomies were rendered and, in select cases, integrated with a three-dimensional computed tomography (CT) image. Irrigated radiofrequency ablation was performed to encircle each pair of ipsilateral PVs. This series included 20 consecutive PAF patients. RA/CS mapping required 5.5 ± 2.6 minutes. In all patients, single (n = 18) or dual (n = 2) transseptal access was successfully achieved. The LA-PV anatomy was rendered using either a circular (14 patients) or penta-array (six patients) catheter in 22 ± 10 minutes; CT image integration was used in 11 patients. Using 49 ± 18 ablation lesions/patient, electrical isolation was achieved in 38/39 ipsilateral PV isolating lesion sets (97%). The procedure time was 244 ± 75 minutes. There were no complications. Completely fluoroless catheter ablation of paroxysmal AF is safely feasible using a combination of ICE and EAM. Copyright © 2010 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  14. Perivascular radiofrequency renal denervation lowers blood pressure and ameliorates cardiorenal fibrosis in spontaneously hypertensive rats

    PubMed Central

    Zhang, Yan; Su, Linan; Zhang, Yunrong; Wang, Qiang; Yang, Dachun; Li, De; Yang, Yongjian; Ma, Shuangtao

    2017-01-01

    Background Catheter-based renal denervation (RDN) is a promising approach to treat hypertension, but innervation patterns limit the response to endovascular RDN and the post-procedural renal artery narrowing or stenosis questions the endovascular ablation strategy. This study was performed to investigate the anti-hypertensive and target organ protective effects of perivascular RDN in spontaneously hypertensive rats (SHR). Methods SHR and normotensive Wistar-Kyoto (WKY) rats were divided into sham group (n = 10), radiofrequency ablation group (n = 20) in which rats received bilateral perivascular ablation with radiofrequency energy (2 watts), and chemical (10% phenol in 95% ethanol) ablation group (n = 12). The tail-cuff blood pressure was measured before the ablation and on day 14 and day 28 after the procedure. The plasma levels of creatinine, urea nitrogen, and catecholamines, urinary excretion of electrolytes and protein, and myocardial and glomerular fibrosis were analyzed and compared among the groups on day 28 after the procedure. Results We identified that 2-watt is the optimal radiofrequency power for perivascular RDN in rats. Perivascular radiofrequency and chemical ablation achieved roughly comparable blood pressure reduction in SHR but not in WKY on day 14 and day 28 following the procedure. Radiofrequency-mediated ablation substantially destroyed the renal nerves surrounding the renal arteries of both SHR and WKY without damaging the renal arteries and diminished the expression of tyrosine hydroxylase, the enzyme marker for postganglionic sympathetic nerves. Additionally, perivascular radiofrequency ablation also decreased the plasma catecholamines of SHR. Interestingly, both radiofrequency and chemical ablation decreased the myocardial and glomerular fibrosis of SHR, while neither increased the plasma creatinine and blood urea nitrogen nor affected the urinary excretion of electrolytes and protein when compared to sham group. Conclusions Radiofrequency

  15. Perivascular radiofrequency renal denervation lowers blood pressure and ameliorates cardiorenal fibrosis in spontaneously hypertensive rats.

    PubMed

    Wei, Shujie; Li, Dan; Zhang, Yan; Su, Linan; Zhang, Yunrong; Wang, Qiang; Yang, Dachun; Li, De; Yang, Yongjian; Ma, Shuangtao

    2017-01-01

    Catheter-based renal denervation (RDN) is a promising approach to treat hypertension, but innervation patterns limit the response to endovascular RDN and the post-procedural renal artery narrowing or stenosis questions the endovascular ablation strategy. This study was performed to investigate the anti-hypertensive and target organ protective effects of perivascular RDN in spontaneously hypertensive rats (SHR). SHR and normotensive Wistar-Kyoto (WKY) rats were divided into sham group (n = 10), radiofrequency ablation group (n = 20) in which rats received bilateral perivascular ablation with radiofrequency energy (2 watts), and chemical (10% phenol in 95% ethanol) ablation group (n = 12). The tail-cuff blood pressure was measured before the ablation and on day 14 and day 28 after the procedure. The plasma levels of creatinine, urea nitrogen, and catecholamines, urinary excretion of electrolytes and protein, and myocardial and glomerular fibrosis were analyzed and compared among the groups on day 28 after the procedure. We identified that 2-watt is the optimal radiofrequency power for perivascular RDN in rats. Perivascular radiofrequency and chemical ablation achieved roughly comparable blood pressure reduction in SHR but not in WKY on day 14 and day 28 following the procedure. Radiofrequency-mediated ablation substantially destroyed the renal nerves surrounding the renal arteries of both SHR and WKY without damaging the renal arteries and diminished the expression of tyrosine hydroxylase, the enzyme marker for postganglionic sympathetic nerves. Additionally, perivascular radiofrequency ablation also decreased the plasma catecholamines of SHR. Interestingly, both radiofrequency and chemical ablation decreased the myocardial and glomerular fibrosis of SHR, while neither increased the plasma creatinine and blood urea nitrogen nor affected the urinary excretion of electrolytes and protein when compared to sham group. Radiofrequency-mediated perivascular RDN may become a

  16. [Radiofrequency ablation in tachycardias due to accessory pathways in a pediatric population].

    PubMed

    Iturralde, P; Saucedo, J; Colín, L; Kershenovich, S; Robledo, R; Garrido, A; González-Hermosillo, J A; Buendía, A

    1994-01-01

    Catheter ablation of accessory atrioventricular pathways using radiofrequency current was attempted in 61 children and young adolescents less than 18 years of age who were referred for treatment of symptomatic supraventricular tachycardia. Thirty-three children had the Wolff-Parkinson-White syndrome and 30 tachyarrhythmias related to an accessory pathway conducting only in retrograde fashion. Ablation of left sided accessory pathways was usually attempted utilizing an arterial approach to the annulus of the mitral valve, only in one case we used the transseptal approach, while the venous route to the atrial aspect of the tricuspid valvular annulus was chosen for right sided accessory connections. Ablation of 55 of 63 accessory connections was achieved (87% success) with a range of 1 to 42 applications of radiofrequency current. The sessions were completed within 19 to 180 minutes, and we used within 16 to 45 watts of radiofrequency current. Two patients had complications as a result of their ablation procedure. One patient had complete heart block but did not require pacemaker implantation, and other one had mitral regurgitation. A second session was necessary in three patients, two of three accessory pathways were ablated, giving a success rate of 90%. During a one year period of follow-up, we had 4 recurrences (7.2%). Catheter ablation using radiofrequency current is a highly effective and safe curative approach for treating young patients with supraventricular tachycardia mediated by accessory pathways.

  17. [Endocavitary ablation for arrhythmias. New modalities of radiofrequency applications. New energy types].

    PubMed

    Cauchemez, B; Lavergne, Th; Extramiana, F; Siliste, C; Leenhardt, A; Coumel, Ph

    2002-04-01

    Radiofrequency remains the reference energy type for catheter ablation of rhythm disorders. In the classic indications, which are atrial flutter or tachycardia, nodal re-entry and Wolff-Parkinson-White syndrome, this energy source has the best cost-efficiency-safety ratio, subject to strict conditions of use. Some new modalities of application have further improved performance, especially active irrigation of the electrode which allows induction of deeper lesions which is very useful for the ablation of difficult atrial flutters, epicardial fascicles of Kent and ischaemic ventricular tachycardias. The only emerging alternative energy type, in the framework of classical ablation, is cold, for which the principal advantages are the homogenous and slightly thrombogenic character for the lesion involved, and the possibility of reversible applications tests which are especially useful in the ablation of structures at risk. The situation is more open-ended concerning research on ablation for atrial fibrillation or the so-called new energy types, such as ultrasound and laser, whilst recognising a renewal in interest, especially for circumferential ablation of the pulmonary veins to isolate the ectopic venous foci. Mechanical energy such as luminous energy is emitted across a catheter balloon deployed at the orifice of the vein, perpendicular to its axis, aiming to reach a continuous circumferential lesion with a minimum of applications. Equally radiofrequency has been undergoing significant evolution for this application, such as by the development of porous catheter balloons with a liquid electrode, as well as by the development of deployable circumferential catheters. Ablation is use for atrial fibrillation, by endocavity atrial segmentation remains a field of research in which radiofrequency retains an important place. It is delivered via multi-electrode catheters according to the new application modalities, either pulsed or by phase interval, which secure better

  18. Contact force and impedance decrease during ablation depends on catheter location and orientation: insights from pulmonary vein isolation using a contact force-sensing catheter.

    PubMed

    Knecht, Sven; Reichlin, Tobias; Pavlovic, Nikola; Schaer, Beat; Osswald, Stefan; Sticherling, Christian; Kühne, Michael

    2015-09-01

    Contact force (CF) sensing during radiofrequency (RF) ablation allows controlling lesion size. The aim of this study was to analyze the impact of catheter tip location and orientation on the association of CF and impedance decrease. We retrospectively analyzed RF applications from 32 patients undergoing catheter ablation for paroxysmal atrial fibrillation using a force-sensing catheter and 3D mapping system. CF, catheter location and orientation relative to the tissue during ablation as well as the absolute impedance decrease during the first 20 s of ablation as a surrogate for lesion effectiveness were analyzed for 791 RF applications. While a higher CF was achieved around the right pulmonary veins (12.5 vs. 11.4 g, p = 0.045), a lower median absolute impedance decrease within the first 20 s was seen around the right veins compared to the left veins (9.3 vs. 10.2 Ω, p = 0.02). With different catheter orientations relative to the tissue, higher CF and impedance decrease was seen when the catheter was orientated parallel or oblique to the tissue (30°-145°) as compared perpendicularly (0-30°) with a median CF of 13.2 vs. 8.0 g (p < 0.001) and a median impedance decrease during the first 20 s of 11 vs. 7 Ω (p < 0.001). Importantly, achieved CF, baseline impedance, catheter orientation and location all independently predicted the initial absolute and relative impedance decrease in a multivariable linear regression model (p < 0.05). The effectiveness of RF ablation lesions, as assessed by the initial impedance decrease, is not only dependent on the achieved catheter CF but also on catheter orientation and location.

  19. Superconductive radiofrequency window assembly

    DOEpatents

    Phillips, H.L.; Elliott, T.S.

    1998-05-19

    The present invention is a superconducting radiofrequency window assembly for use in an electron beam accelerator. The SRF window assembly has a superconducting metal-ceramic design. The SRF window assembly comprises a superconducting frame, a ceramic plate having a superconducting metallized area, and a superconducting eyelet for sealing plate into frame. The plate is brazed to eyelet which is then electron beam welded to frame. A method for providing a ceramic object mounted in a metal member to withstand cryogenic temperatures is also provided. The method involves a new metallization process for coating a selected area of a ceramic object with a thin film of a superconducting material. Finally, a method for assembling an electron beam accelerator cavity utilizing the SRF window assembly is provided. The procedure is carried out within an ultra clean room to minimize exposure to particulates which adversely affect the performance of the cavity within the electron beam accelerator. 11 figs.

  20. Superconducting radiofrequency window assembly

    DOEpatents

    Phillips, H.L.; Elliott, T.S.

    1997-03-11

    The present invention is a superconducting radiofrequency window assembly for use in an electron beam accelerator. The srf window assembly has a superconducting metal-ceramic design. The srf window assembly comprises a superconducting frame, a ceramic plate having a superconducting metallized area, and a superconducting eyelet for sealing plate into frame. The plate is brazed to eyelet which is then electron beam welded to frame. A method for providing a ceramic object mounted in a metal member to withstand cryogenic temperatures is also provided. The method involves a new metallization process for coating a selected area of a ceramic object with a thin film of a superconducting material. Finally, a method for assembling an electron beam accelerator cavity utilizing the srf window assembly is provided. The procedure is carried out within an ultra clean room to minimize exposure to particulates which adversely affect the performance of the cavity within the electron beam accelerator. 11 figs.

  1. Radiofrequency attenuator and method

    DOEpatents

    Warner, Benjamin P.; McCleskey, T. Mark; Burrell, Anthony K.; Agrawal, Anoop; Hall, Simon B.

    2009-11-10

    Radiofrequency attenuator and method. The attenuator includes a pair of transparent windows. A chamber between the windows is filled with molten salt. Preferred molten salts include quarternary ammonium cations and fluorine-containing anions such as tetrafluoroborate (BF.sub.4.sup.-), hexafluorophosphate (PF.sub.6.sup.-), hexafluoroarsenate (AsF.sub.6.sup.-), trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3 C.sup.-). Radicals or radical cations may be added to or electrochemically generated in the molten salt to enhance the RF attenuation.

  2. Radiofrequency attenuator and method

    DOEpatents

    Warner, Benjamin P [Los Alamos, NM; McCleskey, T Mark [Los Alamos, NM; Burrell, Anthony K [Los Alamos, NM; Agrawal, Anoop [Tucson, AZ; Hall, Simon B [Palmerston North, NZ

    2009-01-20

    Radiofrequency attenuator and method. The attenuator includes a pair of transparent windows. A chamber between the windows is filled with molten salt. Preferred molten salts include quarternary ammonium cations and fluorine-containing anions such as tetrafluoroborate (BF.sub.4.sup.-), hexafluorophosphate (PF.sub.6.sup.-), hexafluoroarsenate (AsF.sub.6.sup.-), trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3C.sup.-). Radicals or radical cations may be added to or electrochemically generated in the molten salt to enhance the RF attenuation.

  3. [Percutaneous ablation of atrioventricular junction by radiofrequency current in resistant atrial arrhythmia. Results of a series of 24 patients].

    PubMed

    Sebag, C; Lavergne, T; Ollitrault, J; Cabanis, C; Le Heuzey, J Y; Slama, M; Motté, G; Guize, L

    1992-06-01

    Catheter ablation of the atrioventricular junction may be proposed for the treatment of certain atrial arrhythmias resistant to antiarrhythmic therapy. One of the methods currently being evaluated uses radio-frequency energy which has certain advantages compared with direct current ablation because of the progressive and limited lesions it produces. This technique was used in 24 patients with atrial arrhythmias resistant to antiarrhythmic therapy. The radio-frequency energy was delivered without general anaesthesia with HAT 100 and 200 (OSYPKA) generators in the unipolar mode (average 17.4 watts) for an average period of 22.3 +/- 8 seconds. The catheter (8F USCI suction catheter in the first 18 patients and a 7F Polaris Mansfield, deflectable catheter with a large distal electrode in the remainder) was positioned at the nodo-hisian junction at a point where the two distal electrodes recorded a large atrial deflection and the smallest possible hisian potential. The conduction defects induced during the acute phase generally remain stable in cases of complete atrioventricular block and tend to regress in cases of incomplete atrioventricular block despite initial control of atrioventricular conduction. During follow-up (21 +/- 16 months), 14 patients (58%) remained in complete atrioventricular block, 4 patients (17%) had controlled atrioventricular conduction with an acceptable ventricular rate with associated previously ineffective antiarrhythmic therapy. Radio-frequency ablation was a failure in 6 patients (25%). There were no haemodynamic, rhythmic or ischaemic complications during the acute phase or during follow-up. These results suggest radio-frequency energy is a seductive alternative to direct current ablation for percutaneous modification of atrioventricular conduction in patients with refractory atrial arrhythmias. However, simple modulation of atrioventricular conduction gives aleatory results due to the tendency to regression during follow-up. On the other

  4. Results of a comparative study of low energy direct current with radiofrequency ablation in patients with the Wolff-Parkinson-White syndrome.

    PubMed Central

    Lemery, R; Talajic, M; Roy, D; Lavoie, L; Coutu, B; Hii, J T; Radzik, D; Lavallee, E; Cartier, R

    1993-01-01

    OBJECTIVE--To compare two new power sources for catheter ablation in patients with the Wolff-Parkinson-White syndrome. DESIGN--120 consecutive patients with accessory pathways had catheter ablation. Low energy direct current (DC) was used in the first 60 patients and radio-frequency current in the next 60 patients. SETTING--Electrophysiological laboratory of a large heart institute. PATIENTS--72 men and 48 women (mean (SD) age 35 (14) years (range 9-75)). The accessory pathways were in the left free wall in 73 patients. They were posteroseptal in 35 patients, in the right free wall in five, and anteroseptal in seven. There was no significant difference in the clinical or electrophysiological variables between the two ablation groups. RESULTS--Catheter ablation with low energy direct current was successful in 55/60 patients (92%) and radiofrequency energy was successful in 52/60 patients (87%). Low energy direct current was also successful in four of the eight patients in whom radiofrequency ablation had failed. Radiofrequency ablation was successful in two of the five patients in whom low energy direct current ablation had failed. The mean (SD) procedure and fluoroscopy times for successful ablation were 3.2 (1.5) h and 61 (40) min respectively. These times were similar for both power sources. Accessory pathway conduction recurred in 17 patients (28%) who had low energy direct current and four patients (7%) who received radiofrequency energy (p < 0.004). All patients with recurrence of an accessory pathway had successful re-ablation. CONCLUSIONS--Both new power sources successfully ablated accessory pathways, (overall success rate 94% (113/120 patients)). Radiofrequency ablation, however, did not require general anaesthesia and was associated with a significantly lower rate of recurrence of accessory pathway conduction. Therefore radiofrequency should be used initially for ablation. Low energy direct current may be most useful as a back-up in patients in whom

  5. Radiofrequency Ablation of Lung Tumors

    MedlinePlus

    ... you may need to be admitted overnight for observation. What are Radiofrequency and Microwave Ablation of Lung ... performed on an outpatient basis or with overnight observation in the hospital with general anesthesia. For the ...

  6. Programmable infusion pump and catheter: evaluation using 3-tesla magnetic resonance imaging.

    PubMed

    Shellock, Frank G; Crivelli, Rocco; Venugopalan, Ramakrishna

    2008-07-01

    Objective.  This study assessed 3-Tesla magnetic resonance imaging (MRI) issues for a programmable infusion pump and associated catheters. Methods.  A programmable infusion pump and associated catheters (MedStream Programmable Infusion Pump, 40 mL; SureStream TI Coil-Reinforced Intraspinal Catheter; SureStream TI Connector; and SureStream Silicone Catheter; Codman and Shurtleff Inc., a Johnson & Johnson Company, Raynham, MA, USA) underwent evaluation for magnetic field interactions (deflection angle and torque), heating (transmit/receive body radiofrequency coil; whole-body averaged specific absorption rate, 3 W/kg for 15 min), functional changes (before and after MRI using eight different MRI conditions), and artifacts (T1-weighted spin-echo and gradient-echo pulse sequences) at 3-Tesla. Results.  The programmable infusion pump and associated catheters exhibited minor magnetic field interactions. Heating was not excessive (≤ 1.9°), especially considering the experimental conditions used for this evaluation (ie, relatively high radiofrequency power/specific absorption rate level and use of a nonperfused phantom). The function of three out of six pumps was temporarily altered by exposures to 3-Tesla MRI conditions. Reset was achieved in each case. Artifacts were relatively large for the pump and minor for the catheter. Conclusions.  The programmable infusion pump and catheters will not pose increased risk to a patient examined using 3-Tesla MRI as long as specific safety guidelines are followed, which includes interrogation of the pump post-MRI to ensure proper settings. Artifacts for the programmable infusion pump may impact the diagnostic use of MRI if the area of interest is in the same area or near the device.

  7. In vivo intracardiac OCT imaging through percutaneous access: towards image guided radio-frequency ablation

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Kang, Wei; Carrigan, Thomas; Bishop, Austin; Rosenthal, Noah; Arruda, Mauricio; Rollins, Andrew M.

    2012-01-01

    BACKGROUND Complete catheter-tissue contact and permanent tissue destruction are essential for efficient radio-frequency ablation (RFA) during cardiac arrhythmia treatment. Current methods of monitoring lesion formation are indirect and unreliable. We aim to develop optical coherence tomography (OCT) as an imaging guidance for RFA. OBJECTIVES The purpose of this study is to evaluate the feasibility of using OCT catheter to image endocardia wall in active beating hearts through percutaneous access. This is a critical step toward image guided RFA in a clinic setting. METHODS A cone-scanning forward-viewing OCT catheter was advanced into active beating hearts through percutaneous access in four swine. The OCT catheter was steered by an introducer to touch the endocardia wall. The images were then acquired at 10 frames per second at an axial resolution and lateral resolution of 15 μm. RESULTS We report the first in vivo intracardiac OCT imaging through percutaneous access with a thin and flexible OCT catheter. We are able to acquire high quality OCT images in active beating hearts, observe the polarization-related artifacts induced by the birefringence of myocardium and readily evaluate catheter-tissue contact. CONCLUSIONS It is feasible to acquire OCT images in beating hearts through percutaneous access. The observations indicate that OCT could be a promising technique for in vivo guidance of RFA.

  8. Transcatheter desiccation of the canine left ventricle using radiofrequency energy: a pilot study

    SciTech Connect

    Huang, S.K.; Graham, A.R.; Hoyt, R.H.; Odell, R.C.

    1987-07-01

    Catheter ablation of cardiac tissue by means of direct-current electrical energy is associated with several complications. We assessed the efficacy and safety of closed-chest catheter desiccation of the left ventricular myocardium with microbipolar radiofrequency (RF) energy (750 kHz) in five dogs. The unipolar configuration was used with RF energy delivered between the tip electrode of a standard No. 7F tripolar catheter in the left ventricle and an external patch electrode on the left lateral chest wall. A single application with different RF energy settings (100 J, 200 J, and 300 J) was delivered to three individual endocardial sites of the left ventricle. Ventricular tachycardia or fibrillation was not observed during energy application and 24 hours after ablation, as assessed by a Holter recording. There was no damage to the electrode catheter. Dogs were killed on the fifth day. Pathology showed well-delineated ovoid or round-shaped coagulation necrosis at the ablation sites. Microscopic findings consisted of circumscribed areas of necrosis surrounded by a zone of fibroblastic and mononuclear proliferation. In conclusion, catheter ablation of the ventricular myocardium with RF energy is an apparently safe procedure and can effectively produce discrete areas of injury without destruction of surrounding uninvolved myocardium. This method offers potential clinical utility for catheter ablation of refractory sustained ventricular tachycardia.

  9. Cryoballoon or Radiofrequency Ablation for Paroxysmal Atrial Fibrillation.

    PubMed

    Kuck, Karl-Heinz; Brugada, Josep; Fürnkranz, Alexander; Metzner, Andreas; Ouyang, Feifan; Chun, K R Julian; Elvan, Arif; Arentz, Thomas; Bestehorn, Kurt; Pocock, Stuart J; Albenque, Jean-Paul; Tondo, Claudio

    2016-06-09

    Current guidelines recommend pulmonary-vein isolation by means of catheter ablation as treatment for drug-refractory paroxysmal atrial fibrillation. Radiofrequency ablation is the most common method, and cryoballoon ablation is the second most frequently used technology. We conducted a multicenter, randomized trial to determine whether cryoballoon ablation was noninferior to radiofrequency ablation in symptomatic patients with drug-refractory paroxysmal atrial fibrillation. The primary efficacy end point in a time-to-event analysis was the first documented clinical failure (recurrence of atrial fibrillation, occurrence of atrial flutter or atrial tachycardia, use of antiarrhythmic drugs, or repeat ablation) following a 90-day period after the index ablation. The noninferiority margin was prespecified as a hazard ratio of 1.43. The primary safety end point was a composite of death, cerebrovascular events, or serious treatment-related adverse events. A total of 762 patients underwent randomization (378 assigned to cryoballoon ablation and 384 assigned to radiofrequency ablation). The mean duration of follow-up was 1.5 years. The primary efficacy end point occurred in 138 patients in the cryoballoon group and in 143 in the radiofrequency group (1-year Kaplan-Meier event rate estimates, 34.6% and 35.9%, respectively; hazard ratio, 0.96; 95% confidence interval [CI], 0.76 to 1.22; P<0.001 for noninferiority). The primary safety end point occurred in 40 patients in the cryoballoon group and in 51 patients in the radiofrequency group (1-year Kaplan-Meier event rate estimates, 10.2% and 12.8%, respectively; hazard ratio, 0.78; 95% CI, 0.52 to 1.18; P=0.24). In this randomized trial, cryoballoon ablation was noninferior to radiofrequency ablation with respect to efficacy for the treatment of patients with drug-refractory paroxysmal atrial fibrillation, and there was no significant difference between the two methods with regard to overall safety. (Funded by Medtronic; FIRE

  10. Noninvasive Assessment of Tissue Heating During Cardiac Radiofrequency Ablation Using MRI Thermography

    PubMed Central

    Kolandaivelu, Aravindan; Zviman, Menekhem M.; Castro, Valeria; Lardo, Albert C.; Berger, Ronald D.; Halperin, Henry R.

    2010-01-01

    Background Failure to achieve properly localized, permanent tissue destruction is a common cause of arrhythmia recurrence after cardiac ablation. Current methods of assessing lesion size and location during cardiac radiofrequency ablation are unreliable or not suited for repeated assessment during the procedure. MRI thermography could be used to delineate permanent ablation lesions because tissue heating above 50°C is the cause of permanent tissue destruction during radiofrequency ablation. However, image artifacts caused by cardiac motion, the ablation electrode, and radiofrequency ablation currently pose a challenge to MRI thermography in the heart. In the current study, we sought to demonstrate the feasibility of MRI thermography during cardiac ablation. Methods and Results An MRI-compatible electrophysiology catheter and filtered radiofrequency ablation system was used to perform ablation in the left ventricle of 6 mongrel dogs in a 1.5-T MRI system. Fast gradient-echo imaging was performed before and during radiofrequency ablation, and thermography images were derived from the preheating and postheating images. Lesion extent by thermography was within 20% of the gross pathology lesion. Conclusions MR thermography appears to be a promising technique for monitoring lesion formation and may allow for more accurate placement and titration of ablation, possibly reducing arrhythmia recurrences. PMID:20657028

  11. Catheter associated urinary tract infections

    PubMed Central

    2014-01-01

    Urinary tract infection attributed to the use of an indwelling urinary catheter is one of the most common infections acquired by patients in health care facilities. As biofilm ultimately develops on all of these devices, the major determinant for development of bacteriuria is duration of catheterization. While the proportion of bacteriuric subjects who develop symptomatic infection is low, the high frequency of use of indwelling urinary catheters means there is a substantial burden attributable to these infections. Catheter-acquired urinary infection is the source for about 20% of episodes of health-care acquired bacteremia in acute care facilities, and over 50% in long term care facilities. The most important interventions to prevent bacteriuria and infection are to limit indwelling catheter use and, when catheter use is necessary, to discontinue the catheter as soon as clinically feasible. Infection control programs in health care facilities must implement and monitor strategies to limit catheter-acquired urinary infection, including surveillance of catheter use, appropriateness of catheter indications, and complications. Ultimately, prevention of these infections will require technical advances in catheter materials which prevent biofilm formation. PMID:25075308

  12. Electrifying catheters with light.

    PubMed

    Pekař, Martin; van Rens, Jeannet; van der Mark, Martin B

    2017-04-17

    Smart minimally invasive devices face a connectivity challenge. An example is found in intracardiac echocardiography where the signal transmission and supply of power at the distal end require many thin and fragile wires in order to keep the catheter slim and flexible. We have built a fully functional bench-top prototype to demonstrate that electrical wires may be replaced by optical fibers. The prototype is immediately scalable to catheter dimensions. The absence of conductors will provide intrinsic galvanic isolation as well as radio frequency (RF) and magnetic resonance imaging (MRI) compatibility. Using optical fibers, we show signal transfer of synthetic aperture ultrasound images as well as photo-voltaic conversion to supply all electronics. The simple design utilizes only off the shelf components and holds a promise of cost effectiveness which may be pivotal for translation of these advanced devices into the clinic.

  13. [Rotational stability of angiography catheters].

    PubMed

    Schröder, J; Weber, M

    1992-10-01

    Rotatory stability is a parameter that reflects the ability of a catheter to transmit a rotation applied at the outer end to the catheter tip for the purpose of selective probing. A method for measuring the rotatory stability is described, and the results of rotatory stability measurements of 70 different commercially available catheters are reported. There is an almost linear correlation between the rotatory stability and the difference between the respective fourth power of the external and internal diameter or, approximately, to the fourth power of the external diameter for catheters without wire reinforcement. With the same cross-sectional dimensions, the rotatory stability of teflon, polyethylene, and nylon catheters has an approximate ratio of 1:2:4. Wire reinforcement increases rotatory stability by an average factor of about 3. For catheters of calibers 5 F and 6 F, a correlation between the rotatory stability and the weight of the reinforcing wire mesh is apparent.

  14. Superconductive radiofrequency window assembly

    DOEpatents

    Phillips, Harry Lawrence; Elliott, Thomas S.

    1998-01-01

    The present invention is a superconducting radiofrequency window assembly for use in an electron beam accelerator. The srf window assembly (20) has a superconducting metal-ceramic design. The srf window assembly (20) comprises a superconducting frame (30), a ceramic plate (40) having a superconducting metallized area, and a superconducting eyelet (50) for sealing plate (40) into frame (30). The plate (40) is brazed to eyelet (50) which is then electron beam welded to frame (30). A method for providing a ceramic object mounted in a metal member to withstand cryogenic temperatures is also provided. The method involves a new metallization process for coating a selected area of a ceramic object with a thin film of a superconducting material. Finally, a method for assembling an electron beam accelerator cavity utilizing the srf window assembly is provided. The procedure is carried out within an ultra clean room to minimize exposure to particulates which adversely affect the performance of the cavity within the electron beam accelerator.

  15. Superconducting radiofrequency window assembly

    DOEpatents

    Phillips, Harry L.; Elliott, Thomas S.

    1997-01-01

    The present invention is a superconducting radiofrequency window assembly for use in an electron beam accelerator. The srf window assembly (20) has a superconducting metal-ceramic design. The srf window assembly (20) comprises a superconducting frame (30), a ceramic plate (40) having a superconducting metallized area, and a superconducting eyelet (50) for sealing plate (40) into frame (30). The plate (40) is brazed to eyelet (50) which is then electron beam welded to frame (30). A method for providing a ceramic object mounted in a metal member to withstand cryogenic temperatures is also provided. The method involves a new metallization process for coating a selected area of a ceramic object with a thin film of a superconducting material. Finally, a method for assembling an electron beam accelerator cavity utilizing the srf window assembly is provided. The procedure is carried out within an ultra clean room to minimize exposure to particulates which adversely affect the performance of the cavity within the electron beam accelerator.

  16. Measurement of radiofrequency fields

    SciTech Connect

    Leonowich, J.A.

    1992-05-01

    We are literally surrounded by radiofrequency (RFR) and microwave radiation, from both natural and man-made sources. The identification and control of man-made sources of RFR has become a high priority of radiation safety professionals in recent years. For the purposes of this paper, we will consider RFR to cover the frequencies from 3 kHz to 300 MHz, and microwaves from 300 MHz to 300 GHz, and will use the term RFR interchangeably to describe both. Electromagnetic radiation and field below 3 kHz is considered Extremely Low Frequency (ELF) and will not be discussed in this paper. Unlike x- and gamma radiation, RFR is non-ionizing. The energy of any RFR photon is insufficient to produce ionizations in matter. The measurement and control of RFR hazards is therefore fundamentally different from ionizing radiation. The purpose of this paper is to acquaint the reader with the fundamental issues involved in measuring and safely using RFR fields. 23 refs.

  17. Switches to English during French Service Encounters: Relationships with L2 French Speakers' Willingness to Communicate and Motivation

    ERIC Educational Resources Information Center

    McNaughton, Stephanie; McDonough, Kim

    2015-01-01

    This exploratory study investigated second language (L2) French speakers' service encounters in the multilingual setting of Montreal, specifically whether switches to English during French service encounters were related to L2 speakers' willingness to communicate or motivation. Over a two-week period, 17 French L2 speakers in Montreal submitted…

  18. On the Role of Linguistic Contextual Factors for Morphosyntactic Stabilization in High-Level L2 French

    ERIC Educational Resources Information Center

    Bartning, Inge; Lundell, Fanny Forsberg; Hancock, Victorine

    2012-01-01

    The purpose of this article is to offer contextual linguistic explanations for morphosyntactic deviances (MSDs) in high-level second language (L2) French (30 nonnative speakers vs. 10 native speakers). It is hypothesized that the distribution of formulaic sequences (FSs) and the complexity of information structure will influence the occurrence of…

  19. Creation of transcatheter aortopulmonary and cavopulmonary shunts using magnetic catheters: feasibility study in swine.

    PubMed

    Levi, Daniel S; Danon, Saar; Gordon, Brent; Virdone, Nicky; Vinuela, Fernando; Shah, Sanjay; Carman, Greg; Moore, John W

    2009-05-01

    Surgical shunts are the basic form of palliation for many types of congenital heart disease. The Glenn shunt (superior cavopulmonary connection) and central shunt (aortopulmonary connection) represent surgical interventions that could potentially be accomplished by transcatheter techniques. We sought to investigate the efficacy of using neodymium iron boron (NdFeB) magnetic catheters to create transcatheter cavopulmonary and aortopulmonary shunts. NdFeB magnets were machined and integrated into catheters. "Target" catheters were placed in the pulmonary arteries (PAs), and radiofrequency "perforation" catheters were placed in either the descending aorta (DAo) for central shunts or the superior vena cava (SVC) for Glenn shunts. The magnet technique or "balloon target" method was used to pass wires from the DAo or the SVC into the PA. Aortopulmonary and cavopulmonary connections were then created using Atrium iCAST covered stents. Magnet catheters were used to perforate the left pulmonary artery from the DAo, thereby establishing a transcatheter central shunt. Given the orientation of the vasculature, magnetic catheters could not be used for SVC-to-PA connections; however, perforation from the SVC to the right pulmonary artery was accomplished with a trans-septal needle and balloon target. Transcatheter Glenn or central shunts were successfully created in four swine.

  20. [Intravenous catheters and nosocomial infection].

    PubMed

    Reingardiene, Dagmara

    2004-01-01

    Peripheral, especially central venous catheters, are used with increasing frequency in the intensive care unit and in general medical wards to administer intravenous fluids and blood products, drugs, parenteral nutrition, and to monitor hemodynamic status. Catheter infection is associated with increased morbidity, mortality, and duration of hospital stay. Risk factors in the development of catheter colonization and bloodstream infections include patient factors (increased risk associated with malignancy, neutropenia, and shock) and treatment-related factors (increased risk associated with total parenteral nutrition, intensive care unit admission for any reason, and endotracheal intubation). In this review article terms and definitions of catheter-related infections, pathophysiology and epidemiology of "catheter sepsis", factors determining risk of infection, catheter types and materials, insertion procedure, choice of insertion site, indwelling time, dressing and care of the insertion site, various preventive strategies and future developments, special situations and procedures, and treatment are discussed. Reducing catheter infections rates requires a multiple-strategy approach. Therefore, intensive care units and other locations where catheters are used should implement strict guidelines and protocols for catheter insertion, care, and maintenance.

  1. Light modulated electron beam driven radiofrequency emitter

    DOEpatents

    Wilson, M.T.; Tallerico, P.J.

    1979-10-10

    The disclosure relates to a light modulated electron beam-driven radiofrequency emitter. Pulses of light impinge on a photoemissive device which generates an electron beam having the pulse characteristics of the light. The electron beam is accelerated through a radiofrequency resonator which produces radiofrequency emission in accordance with the electron, hence, the light pulses.

  2. Radiofrequency power deposition near metallic wires during MR imaging: feasibility study using T1-weighted thermal imaging.

    PubMed

    Oulmane, F; Detti, V; Grenier, D; Perrin, E; Saint-Jalmes, H

    2007-01-01

    The presence of metallic conductors (implants, wires or catheters) is prohibited in MR imaging for safety purpose with respect to radiofrequency (RF) power deposition caused by RF excitation B1 field. This work describes the use of T1-weigthed MR imaging for estimating a thermal map around a metallic (copper) wire located in the center of a MR imaging unit during an imaging sequence. The experimental set up and the methodology used for capturing the elevation of temperature created by radiofrequency power deposition around the wire is presented. A proof of its efficiency to followup temperature elevation about 0,5 degrees C in a milimetric region of interest (pixel size: 1 x 1 mm2, slice thickness 5 mm) located around the wire is given, leading to further developments of MR imaging in presence of metallic implants, coils or catheters.

  3. The Incidence of Audible Steam Pops Is Increased and Unpredictable With the ThermoCool® Surround Flow Catheter During Left Atrial Catheter Ablation: A Prospective Observational Study.

    PubMed

    Theis, Cathrin; Rostock, Thomas; Mollnau, Hanke; Sonnenschein, Sebastian; Himmrich, Ewald; Kämpfner, Denise; Ocete, Blanca Quesada; Bock, Karsten; Münzel, Thomas; Konrad, Torsten

    2015-06-08

    Open irrigated radiofrequency (RF) ablation catheters with a porous tip (56 holes, TC-SF) permit delivering RF energy in a temperature-controlled mode without temperature rise. This prospective observational study investigated the association of different catheter parameters on the occurrence of audible steam pops during left atrial (LA) ablation. A total of 226 patients underwent TC-SF catheter ablation for atrial fibrillation. RF power delivery, impedance and catheter tip temperature were continually recorded throughout the ablation. Pulmonary vein isolation was performed with a maximum of 27 W and LA electrogram-guided or linear ablation with a maximum of 30 W. A total of 59 audible steam pops occurred, 2 of them resulting in pericardial tamponade. In the initial 89 patients, with an irrigation flow rate of 10 mL/min, 18 steam pops with one tamponade occurred in 12 (14%) patients. Subsequently, the irrigation flow rate was increased to 20 mL/min in the following 137 patients, resulting in the occurrence of 41 steam pops including one case of tamponade in a total of 30 (22%) patients. The maximal power was significantly higher in RF applications associated with a pop than those that did not. In only 12 (20%) steam pops, a significant impedance change occurred immediately before pop occurrence (4 [7%] impedance rise >10 ohm, 8 [13%] impedance drop >15 ohm). The TC-SF catheter does not provide sufficient feedback from the ablated tissue to prevent steam popping. © 2015 Wiley Periodicals, Inc.

  4. Radiofrequency fields and teratogenesis.

    PubMed

    Heynick, Louis N; Merritt, James H

    2003-01-01

    Experimental studies that sought teratologic effects or developmental abnormalities from exposure to radiofrequency electromagnetic fields (RFEMF) in the range 3 kHz-300 GHz are critically reviewed for their possible consequences on human health. Those studies were conducted on beetles, birds, rodents, and nonhuman primates. Collectively, those experimental studies indicate that teratologic effects can occur only from exposure levels that cause biologically detrimental increases in body temperature. No reliable experimental evidence was found for nonthermal teratologic effects; rodents, mouse fetuses, and perinatal mice are more susceptible to such effects than rats. The primary confirmed effect in rats at high RFEMF levels was initial weight deficits in fetuses and neonates that decreased with infant growth. More generally from findings with pregnant mammals, exposures at RFEMF levels far higher than those permitted under the IEEE human exposure guidelines are necessary to reach or exceed cited experimental thresholds for maternal temperature increases. Some results indicated that the levels necessary to cause such effects in pregnant mammals could exceed those lethal to the dams. In a behavioral study of squirrel monkeys, no effects were observed on usual dam-offspring interactions or EEGs, but unexpected deaths of a number of offspring had occurred. However, this finding was not confirmed in a study solely on infant death using a larger number of subjects for greater statistical validity. Also reviewed were epidemiologic studies of various human populations considered to have been chronically exposed to environmental levels of RFEMF. Early studies on the incidence of congenital anomalies yielded no credible evidence that chronic exposure of pregnant women or of fathers exposed to RFEMF from nearby sources at levels below those guidelines would cause any anomalies in their offspring. The findings of studies on pregnancy outcomes of female physiotherapists

  5. The biophysics of renal sympathetic denervation using radiofrequency energy.

    PubMed

    Patel, Hitesh C; Dhillon, Paramdeep S; Mahfoud, Felix; Lindsay, Alistair C; Hayward, Carl; Ernst, Sabine; Lyon, Alexander R; Rosen, Stuart D; di Mario, Carlo

    2014-05-01

    Renal sympathetic denervation is currently performed in the treatment of resistant hypertension by interventionists who otherwise do not typically use radiofrequency (RF) energy ablation in their clinical practice. Adequate RF lesion formation is dependent upon good electrode-tissue contact, power delivery, electrode-tissue interface temperature, target-tissue impedance and the size of the catheter's active electrode. There is significant interplay between these variables and hence an appreciation of the biophysical determinants of RF lesion formation is required to provide effective and safe clinical care to our patients. In this review article, we summarize the biophysics of RF ablation and explain why and how complications of renal sympathetic denervation may occur and discuss methods to minimise them.

  6. 5-F catheter in cerebral angiography

    SciTech Connect

    O'Reilly, G.V.; Naheedy, M.H.; Colucci, V.M.; Hammerschlag, S.B.

    1981-11-01

    Although the 5-F catheter is reputed to cause less vascular trauma than larger catheters, subintimal injections of contrast material have occurred following intimal damage by the catheter tip. Microscopic studies of the tips of two widely used 5-F polyethylene catheters have revealed a difference in configuration resulting in one of the catheters becoming markedly damaged during angiography. The authors make recommendations for finishing and protecting the catheter tip.

  7. Import catheter in erectile dysfunction.

    PubMed

    Kayigil, O; Atahan, O; Metin, A

    1997-08-01

    We propose an alternative technique for intracavernous self-injection of sodium nitroprusside for erectile dysfunction by inserting a Medtronic ImPort* catheter with a valved tip. A silicone catheter was implanted in 3 patients with psychogenic impotence. The reservoir, which is used for vasoactive agent injection, was implanted laterally to the anterosuperior iliac spine and the distal tip of the catheter was inserted into the corpora cavernosa via a subcutaneous tunnel. The injection technique was taught to the patient and the initial injection was performed 1 week later. All patients and partners were satisfied with the technique and quality of erections at a mean followup of 14 months. There were no major local complications due to catheter implantation and no systemic complications due to sodium nitroprusside injection. An alternative technique for intracavernous pharmacotherapy of inserting an ImPort catheter prevented the complications of intracavernous injections in patients with erectile dysfunction.

  8. Architecture of the pulmonary veins: relevance to radiofrequency ablation

    PubMed Central

    Ho, S; Cabrera, J; Tran, V; Farre, J; Anderson, R; Sanchez-Quintana, D

    2001-01-01

    BACKGROUND—Radiofrequency ablation of tissues in pulmonary veins can eliminate paroxysmal atrial fibrillation.
OBJECTIVE—To explore the characteristics of normal pulmonary veins so as to provide more information relevant to radiofrequency ablation.
METHODS—20 structurally normal heart specimens were examined grossly. Histological sections were made from 65 pulmonary veins.
RESULTS—The longest myocardial sleeves were found in the superior veins. The sleeves were thickest at the venoatrial junction in the left superior pulmonary veins. For the superior veins, the sleeves were thickest along the inferior walls and thinnest superiorly. The sleeves were composed mainly of circularly or spirally oriented bundles of myocytes with additional bundles that were longitudinally or obliquely oriented, sometimes forming mesh-like arrangements. Fibrotic changes estimated at between 5% and 70% across three transverse sections were seen in 17 veins that were from individuals aged 30 to 72 years.
CONCLUSIONS—The myocardial architecture in normal pulmonary veins is highly variable. The complex arrangement, stretch, and increase in fibrosis may produce greater non-uniform anisotropic properties.


Keywords: arrhythmias; catheter ablation; fibrillation; cardiac veins PMID:11514476

  9. Monoplane 3D reconstruction of mapping ablation catheters: a feasibility study.

    PubMed

    Fallavollita, P

    2010-01-01

    Radiofrequency (RF) catheter ablation has transformed treatment for arrhythmias and has become first-line therapy for some tachycardias. The precise localization of the arrhythmogenic site and the positioning of the RF catheter over that site are problematic: they can impair the efficiency of the procedure and are time consuming (several hours). This study evaluates the feasibility of using only single plane C-arm images in order to estimate the 3D coordinates of RF catheter electrodes in a cardiac phase. The method makes use of a priori 3D model of the RF mapping catheter assuming rigid body motion equations in order to estimate the 3D locations of the catheter tip-electrodes in single view C-arm fluoroscopy images. Validation is performed on both synthetic and clinical data using computer simulation models. The authors' monoplane reconstruction algorithm is applied to a 3D helix mimicking the shape of a catheter and undergoing solely rigid motion. Similarly, the authors test the feasibility of recovering nonrigid motion by applying their method on true 3D coordinates of 13 ventricular markers from a sheep's ventricle. The results of this study showed that the proposed monoplane algorithm recovers rigid motion adequately when using the spatial positions of a catheter in six consecutive C-arm image frames yielding maximum 3D root mean squares errors of 4.3 mm. On the other hand, the suggested algorithm did not recover nonrigid motion precisely as suggested by a maximum 3D root mean square value of 8 mm. Since RF catheter electrodes are rigid structures, the authors conclude that there is promise in recovering the 3D coordinates of the electrodes when making use of only single view images. Future work will involve adding nonrigid motion equations to their algorithm, which will then be applied to actual clinical data.

  10. a Radio-Frequency

    NASA Astrophysics Data System (ADS)

    Foo, Thomas Kwok-Fah

    Radio-frequency (RF) inhomogeneity encountered in magnetic resonance (MR) imaging poses a significant impediment to obtaining images of the highest diagnostic quality. This inhomogeneity arises from the conductivity effect, which attenuates the RF field with increasing depth, and the permittivity effect. The latter is the dominant effect at 1.5 Tesla (64 MHz), and contributes to standing waves within the body. A theoretical model has been developed which describes these effects for an infinitely long right circularly cylindrical object inside a concentric RF coil and RF shield. This model assumes that the RF field propagates as a travelling wave in the z direction, along the long axis of the cylinder. The resulting solutions adequately predict the field distribution for RF coils which have both a finite wavelength and an infinite wavelength in z. This corresponds to high-pass and low-pass birdcage resonators, respectively, that are in general used in MR imaging. Standing wave models are easily obtained from the superposition of solutions of two travelling waves in opposite directions. The results of this model indicate that the axial propagation constant k_{z} is a strong function of the dielectric present in the coil -to-shield space. The field distribution in the axial plane can be represented by the Bessel function J_1(k _{rho}r), where k _sp{rho}{2} = k^2-k_sp{z}{2} . By varying the dielectric material occupying the coil-to-shield space, an optimum value of k _{z} can be obtained for a particular coil and shield configuration which minimizes the amplitude variations in the axial plane. Experimental verification of the theoretical model has been obtained. These measurements were performed on a non-resonant, travelling wave test coil with a saline phantom as a load simulating the body. The measured field profiles in the axial plane agree with the predicted values, establishing the validity of the theoretical model. As expected, optimal RF homogeneity was obtained

  11. Outcomes after cryoablation vs. radiofrequency in patients with paroxysmal atrial fibrillation: impact of pulmonary veins anatomy.

    PubMed

    Khoueiry, Z; Albenque, J-P; Providencia, R; Combes, S; Combes, N; Jourda, F; Sousa, P A; Cardin, C; Pasquie, J-L; Cung, T T; Massin, F; Marijon, E; Boveda, S

    2016-09-01

    Pulmonary vein isolation is the mainstay of treatment in catheter ablation of paroxysmal atrial fibrillation (AF). Cryoballoon ablation has been introduced more recently than radiofrequency ablation, the standard technique in most centres. Pulmonary veins frequently display anatomical variants, which may compromise the results of cryoballoon ablation. We aimed to evaluate the mid-term outcomes of cryoballoon ablation in an unselected population with paroxysmal AF from an anatomical viewpoint. Consecutive patients with paroxysmal AF who underwent a first procedure of cryoballoon ablation or radiofrequency were enrolled in this single-centre study. All patients underwent systematic standardized follow-up. Comparisons between radiofrequency and cryoballoon ablation (Arctic Front™ or Arctic Front Advance™) were performed regarding safety and efficacy endpoints, according to pulmonary vein (PV) anatomical variants. A total of 687 patients were enrolled (376 radiofrequency and 311 cryoballoon ablation). Baseline characteristics and distribution of PV anatomical variants were generally similar in the groups. After a mean follow-up of 14 ± 8 months, there was no difference in the incidence of relapse (17.0% cryoballoon ablation vs. 14.1% radiofrequency, P = 0.25). We observed no interaction of PV anatomical variants on mid-term procedural success. Our findings suggest that mid-term outcomes of cryoballoon ablation for paroxysmal AF ablation are similar to those of radiofrequency, regardless of PV anatomy. The presence of anatomical variants of PVs should not discourage the referral of patients with paroxysmal AF for cryoballoon ablation. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

  12. Intralesional radiofrequency in venous malformations.

    PubMed

    Garg, S; Kumar, S; Singh, Y B

    2015-03-01

    Venous malformations are usually asymptomatic and managed conservatively. Treatment, in the form of laser, sclerotherapy, or resection, is needed only if lesions present with symptoms or cosmetic deformity. The aim of this study was to find out how effective radiofrequency ablation was in patients with incomplete or unsatisfactory resolution of a venous malformation after an intralesional injection of bleomycin. During the 5 year period 2008-2012, we organised a prospective, clinical study at a tertiary care centre. Patients were selected from the outpatient department of the Lady Hardinge Medical College and associated hospitals, New Delhi, India. Five patients with venous malformations were treated by intralesional injection of bleomycin in a dose of 0.5U/kg body weight, which was repeated every 2 weeks for a total of 8 injections. They then had multiple intralesional radiofrequency ablation every 2 months until a satisfactory outcome was achieved. After the initial 8 doses the reduction in the size of the lesions was minimal (less than 50%). After 2-4 applications of radiofrequency ablation there was appreciable reduction in the size of the lesions (about 80%) with good functional and cosmetic outcomes. Radiofrequency ablation is an effective adjunct for patients with venous malformations of the head and neck that have not responded satisfactorily to intralesional injection of bleomycin. To our knowledge radiofrequency ablation after intralesional injection of bleomycin has not previously been described as a treatment for venous malformations. Copyright © 2014 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  13. Precision test apparatus for evaluating the heating pattern of radiofrequency ablation devices.

    PubMed

    Chang, I; Beard, B

    2002-11-01

    Radiofrequency has established itself as a useful technique for managing cardiac arrhythmias and treating soft tissue tumors. However, despite its pervasive use, many of the biophysical principals needed to fully understand and optimize the radiofrequency ablation technique have not been explored. We have designed a test rig that is useful for studying the heat transfer mechanisms that affect the outcome of radiofrequency ablation devices. Using both solid and liquid phantom materials, which simulate body tissues and blood, the test rig is designed for systematic testing of the effects of predictable flow patterns on the temperature profiles generated within the solid phantom. The test rig consists of a custom built thermistor array, a linear test chamber, and a radiofrequency generator. We calibrate the flow of a liquid phantom material to demonstrate that predictable laminar flow profiles are generated. To demonstrate the performance of the ablation system, we present preliminary data attained using a commercially available cardiac ablation catheter. The advantages of this test system are its flexibility, its reproducibility, its precision, and its low cost. Thus, it is ideally suited for studying a variety of complex ablation problems involving multiple tissues types and complex blood flow geometries.

  14. [RADIOFREQUENCY ABLATION FOR THE TREATMENT OF VARICOSE VEINS].

    PubMed

    Sugiyama, Satoru; Miyade, Yoshio; Inaki, Yasuhiko

    2015-05-01

    Significant advances in the endovenous technique for treating incompetent saphenous veins could change the surgical strategy in patients with varicose veins. Radiofrequency ablation (RFA) was approved as a new technique for the treatment of varicose veins in Japan in June 2014. In RFA, the ablation temperature is controlled by a sensor at the upper end of the catheter. The vein wall is heated with stable conductive power of 120 degrees C, resulting in endothelial denudation. The RFA method was approved in 1998 in Europe and in 1999 in the USA. The ClosurePLUS catheter was developed in 2003 and ClosureFAST in 2006. High occlusion rates and lower postoperative complication rates were reported with ClosureFAST than with ClosurePLUS. It is expected that this new ablation technique will control saphenous vein reflux with less pain and less ecchymosis after surgery. The treatment of varicose veins is less invasive with RFA devices and will become widely accepted as an alternative to conventional surgery for varicose veins in Japan.

  15. Balloon catheter coronary angioplasty

    SciTech Connect

    Angelini, P.

    1987-01-01

    The author has produced a reference and teaching book on balloon angioplasty. Because it borders in surgery and is performed on an awake patient without circulatory assistance, it is a complex and demanding procedure that requires thorough knowledge before it is attempted. The text is divided into seven sections. The first section describes coronary anatomy and pathophysiology, defines the objectives and mechanisms of the procedure and lists four possible physiologic results. The next section describes equipment in the catheterization laboratory, catheters, guidewires and required personnel. The following section is on the procedure itself and includes a discussion of examination, testing, technique and follow-up. The fourth section details possible complications that can occur during the procedure, such as coronary spasms, occlusion, thrombosis, perforations and ruptures, and also discusses cardiac surgery after failed angioplasty. The fifth section details complex or unusual cases that can occur. The sixth and seventh sections discuss radiation, alternative procedures and the future of angioplasty.

  16. Successful catheter ablation of a left anterior accessory pathway from the non-coronary cusp of the aortic valve.

    PubMed

    Laranjo, Sérgio; Oliveira, Mário; Trigo, Conceição

    2015-08-01

    Left anterior accessory pathways are considered to be rare findings. Catheter ablation of accessory pathways in this location remains a challenging target, and few reports about successful ablation of these accessory pathways are available. We describe our experience regarding a case of a manifest left anterior accessory pathway ablation using radiofrequency energy at the junction of the left coronary cusp with the non-coronary cusp.

  17. Successful Treatment of Persistent Pain After Pectus Excavatum Repair Using Paravertebral Nerve Radiofrequency Thermoablation.

    PubMed

    Ladenhauf, Hannah Noemi; Stundner, Ottokar; Likar, Rudolf; Schnöll, Jörg; Metzger, Roman P

    2017-01-01

    We present a case of a 25-year-old male patient suffering from severe prolonged pain after uneventful pectus excavatum repair that could be treated successfully by paravertebral nerve radiofrequency thermoablation. The patient was scheduled for a minimally invasive Nuss pectus excavatum repair. Surgical correction was performed under general anesthesia in combination with a thoracic peridural catheter. The immediate postoperative course was uneventful; however, the patient developed severe prolonged bilateral chest wall pain across segments T8 and T9. After failure of conservative treatment options, a specialized interventional anesthesiologist performed paravertebral nerve radiofrequency thermoablation of segment T9 bilaterally, after which the patient was pain free until scheduled removal of the pectus bar 3 years after placement.

  18. What is behind radiofrequency delivery at the cavo-tricuspid isthmus?

    PubMed

    Filgueiras-Rama, David; Arceluz, Martín; Castrejón, Sergio; Estrada, Alejandro; Figueroa, Jorge; Ortega-Molina, Marta; Delgado, Reina; Merino, José L

    2014-01-01

    Catheter-based ablation of isthmus-dependent common atrial flutter results in very high success rates and almost no complications. However, bidirectional conduction block through the isthmus may be challenging in a small percentage of patients regarding the use of high power and high temperature settings during radiofrequency delivery. Anatomical and physiological circumstances may be the reason for such difficulties to achieve bidirectional block at the cavo-tricuspid isthmus. However, in the present case we show edema formation after multiple shots of radiofrequency delivery at the cavo-tricuspid isthmus, which complicates the achievement of bidirectional conduction block. Copyright © 2013 Instituto Nacional de Cardiología Ignacio Chávez. Published by Masson Doyma México S.A. All rights reserved.

  19. [Catheter-related infections: microbiology].

    PubMed

    Timsit, J F

    2005-03-01

    Coagulase negative staphylococci, Staphylococcus aureus and Pseudomonas sp. are the most frequent microorganisms responsible for catheter-related infections. A relative frequency of microorganisms varies according to the countries, microenvironment and outbreaks of multiresistant bacterias. Infections due to fungi, S. aureus and Pseudomonas sp. are associated with the more severe complications. Recent data suggest that chlorhexidine, either used for cutaneous antisepsis or for catheter impregnation decreases infections due to gram positive cocci. Ecological data should be taken into account when deciding a probabilistic treatment in case of suspicion of catheter-related infection.

  20. Incorporating a Gaussian model at the catheter tip for improved registration of preoperative surface models

    NASA Astrophysics Data System (ADS)

    Rettmann, M. E.; Holmes, D. R., III; Packer, D. L.; Robb, R. A.

    2011-03-01

    Atrial fibrillation is a common cardiac arrhythmia in which aberrant electrical activity cause the atria to quiver which results in irregular beating of the heart. Catheter ablation therapy is becoming increasingly popular in treating atrial fibrillation, a procedure in which an electrophysiologist guides a catheter into the left atrium and creates radiofrequency lesions to stop the arrhythmia. Typical visualization tools include bi-plane fluoroscopy, 2-D ultrasound, and electroanatomic maps, however, recently there has been increased interest in incorporating preoperative surface models into the procedure. Typical strategies for registration include landmark-based and surface-based methods. Drawbacks of these approaches include difficulty in accurately locating corresponding landmark pairs and the time required to sample surface points with a catheter. In this paper, we describe a new approach which models the catheter tip as a Gaussian kernel and eliminates the need to collect surface points by instead using the stream of continuosly tracked catheter points. We demonstrate the feasibility of this technique with a left atrial phantom model and compare the results with a standard surface based approach.

  1. Real-time circumferential mapping catheter tracking for motion compensation in atrial fibrillation ablation procedures

    NASA Astrophysics Data System (ADS)

    Brost, Alexander; Bourier, Felix; Wimmer, Andreas; Koch, Martin; Kiraly, Atilla; Liao, Rui; Kurzidim, Klaus; Hornegger, Joachim; Strobel, Norbert

    2012-02-01

    Atrial fibrillation (AFib) has been identified as a major cause of stroke. Radiofrequency catheter ablation has become an increasingly important treatment option, especially when drug therapy fails. Navigation under X-ray can be enhanced by using augmented fluoroscopy. It renders overlay images from pre-operative 3-D data sets which are then fused with X-ray images to provide more details about the underlying soft-tissue anatomy. Unfortunately, these fluoroscopic overlay images are compromised by respiratory and cardiac motion. Various methods to deal with motion have been proposed. To meet clinical demands, they have to be fast. Methods providing a processing frame rate of 3 frames-per-second (fps) are considered suitable for interventional electrophysiology catheter procedures if an acquisition frame rate of 2 fps is used. Unfortunately, when working at a processing rate of 3 fps, the delay until the actual motion compensated image can be displayed is about 300 ms. More recent algorithms can achieve frame rates of up to 20 fps, which reduces the lag to 50 ms. By using a novel approach involving a 3-D catheter model, catheter segmentation and a distance transform, we can speed up motion compensation to 25 fps which results in a display delay of only 40 ms on a standard workstation for medical applications. Our method uses a constrained 2-D/3-D registration to perform catheter tracking, and it obtained a 2-D tracking error of 0.61 mm.

  2. An integrated semicompliant balloon ultrasound catheter for quantitative feedback and image guidance during stent deployment.

    PubMed

    Choi, Charles D; Savage, James; Stephens, Douglas N; O'Donnell, Matthew

    2005-09-01

    An integrated balloon ultrasound catheter prototype was designed to image from inside the balloon for real-time guidance during stent deployment. It was fabricated using a semicompliant balloon material (polyethylene) and a 20 MHz, 64-element circumferential ultrasound array. A commercial stent, nominally 4.4 mm in diameter and 12 mm in length, was used for a phantom study and placed along the length of the integrated balloon ultrasound catheter. A rubber phantom was created with an elastic modulus of 175 kPa with a 4.36 mm diameter lumen. Real-time balloon pressure measurements were recorded using a digital pressure sensor, and real-time radio-frequency (RF) data were captured as the balloon was inflated. The slope of the area-pressure ratio (APR) was compared to a reference measure of the balloon and stent expanded in water to determine a measure for optimal stent deployment. The results clearly indicate stent deployment at 11.1 atm using this metric. The APR slope could serve as quantitative feedback parameter for guiding stent deployment to reduce arterial injury and subsequent restenosis. After the stent deployment experiment, RF data were captured as the balloon catheter was moved along the length of the stent in pullback mode to confirm successful stent deployment. Ultimately, an integrated balloon ultrasound catheter could serve as a single catheter intervention device by providing real-time intravascular ultrasound (IVUS) imaging and quantitative feedback during stent deployment.

  3. Myocardial injury during radiofrequency and cryoablation of typical atrial flutter.

    PubMed

    Saygi, Serkan; Drca, Nikola; Insulander, Per; Schwieler, Jonas; Jensen-Urstad, Mats; Bastani, Hamid

    2016-08-01

    Cardiac enzyme elevation after radiofrequency (RF) catheter ablation of atrial flutter (AFL) is common. Some studies found that cryoablation (CRYO) of AFL, compared to RF, is associated with higher levels of troponin, a finding that may indicate CRYO causes a greater amount of myocardial injury than RF. However, other investigations found no significant differences between troponin levels after CRYO versus RF. We have in a randomized study compared the post-procedural troponin I levels in RF and CRYO and the possible relation to procedural outcome and complications. We randomized 153 patients with cavotricuspid isthmus (CTI)-dependent AFL to CRYO or RF (78 CRYO; 75 RF). RF was performed with a 3.5-mm open-irrigated-tip catheter, and CRYO was performed with an 8-mm-tip catheter. Troponin I levels were measured before and 6 h after ablation. Acute procedural success was achieved in 71/75 patients in the RF and in 72/78 patients in the CRYO. Troponin I levels were significantly elevated in both groups (baseline 0.012, 6th hour 0.35 ng/ml; p < 0.001). Troponin I levels were similar for RF and CRYO. Troponin I levels were higher in patients with acute failure compared to patients with acute success (0.48 ± 0.4 and 0.34 ± 0.16 ng/ml, p = 0.029); however, there was no difference between patients with or without late recurrence. There were no major complications in any group. RF and CRYO for CTI-dependent AFL resulted in similar amounts of procedural myocardial injury. Troponin I levels had no prognostic value for late recurrence of AFL and there were no complications related to high troponin I levels.

  4. In vivo intracardiac optical coherence tomography imaging through percutaneous access: toward image-guided radio-frequency ablation

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Kang, Wei; Carrigan, Thomas; Bishop, Austin; Rosenthal, Noah; Arruda, Mauricio; Rollins, Andrew M.

    2011-11-01

    Complete catheter-tissue contact and permanent tissue destruction are essential for efficient radio-frequency ablation (RFA) during cardiac arrhythmia treatment. Current methods of monitoring lesion formation are indirect and unreliable. The purpose of this study is to evaluate the feasibility of using optical coherence tomography (OCT) catheter to image endocardial wall in actively beating hearts through percutaneous access. We reported the first in vivo intracardiac OCT imaging through percutaneous access with a thin and flexible OCT catheter. This is a critical step toward image-guided RFA in a clinical setting. A cone-scanning forward-viewing OCT catheter was advanced into beating hearts through percutaneous access in four swine. The OCT catheter was steered by an introducer to touch the endocardial wall. We are able to acquire high quality OCT images in beating hearts, observe the polarization-related artifacts induced by the birefringence of myocardium, and readily evaluate catheter-tissue contact. The observations indicate that OCT could be a promising technique for in vivo guidance of RFA.

  5. JAG Tearing Technique with Radiofrequency Guide Wire for Aortic Fenestration in Thoracic Endovascular Aneurysm Repair

    SciTech Connect

    Ricci, Carmelo; Ceccherini, Claudio Leonini, Sara; Cini, Marco; Vigni, Francesco; Neri, Eugenio; Tucci, Enrico; Benvenuti, Antonio; Tommasino, Giulio; Sassi, Carlo

    2012-02-15

    An innovative approach, the JAG tearing technique, was performed during thoracic endovascular aneurysm repair in a patient with previous surgical replacement of the ascending aorta with a residual uncomplicated type B aortic dissection who developed an aneurysm of the descending thoracic aorta with its lumen divided in two parts by an intimal flap. The proximal landing zone was suitable to place a thoracic stent graft. The distal landing zone was created by cutting the intimal flap in the distal third of the descending thoracic aorta with a radiofrequency guide wire and intravascular ultrasound catheter.

  6. Usefulness of CT During Renal Arteriography: A Case of Percutaneous Radiofrequency Ablation for Renal Cell Carcinoma

    SciTech Connect

    Tanigawa, Noboru Kariya, Shuji; Komemushi, Atsushi; Kojima, Hiroyuki; Sawada, Satoshi

    2004-11-15

    A 64-year-old man with a unilateral 15 mm diameter renal cell carcinoma underwent percutaneous radiofrequency ablation (RFA) assisted by CT during renal arteriography (angio-CT). Prior to placement of the needle electrode, a 5 Fr angio-catheter was placed in the right renal artery, and angio-CT was performed before, during and after the procedure. Since multiple angio-CT can be performed using a small amount of diluted contrast agent, RFA can be monitored without impairing renal function. As a result, this imaging combination was found to be useful for determining the end point of ablation.

  7. JAG tearing technique with radiofrequency guide wire for aortic fenestration in thoracic endovascular aneurysm repair.

    PubMed

    Ricci, Carmelo; Ceccherini, Claudio; Leonini, Sara; Cini, Marco; Vigni, Francesco; Neri, Eugenio; Tucci, Enrico; Benvenuti, Antonio; Tommasino, Giulio; Sassi, Carlo

    2012-02-01

    An innovative approach, the JAG tearing technique, was performed during thoracic endovascular aneurysm repair in a patient with previous surgical replacement of the ascending aorta with a residual uncomplicated type B aortic dissection who developed an aneurysm of the descending thoracic aorta with its lumen divided in two parts by an intimal flap. The proximal landing zone was suitable to place a thoracic stent graft. The distal landing zone was created by cutting the intimal flap in the distal third of the descending thoracic aorta with a radiofrequency guide wire and intravascular ultrasound catheter.

  8. Central Venous Catheter (Central Line)

    MedlinePlus

    ... ATS Patient Education Series © 2007 American Thoracic Society ■ ■ Infection— Any tube (catheter) entering the body can make it easier for bacteria from the skin to get into the bloodstream. ...

  9. Peripherally inserted central catheter - insertion

    MedlinePlus

    ... nontunneled central venous catheters. In: Mauro MA, Murphy KPJ, Thomson KR, et al., eds. Image-Guided Interventions . ... by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is ...

  10. Catheter Ablation for Ventricular Arrhythmias

    PubMed Central

    Nof, Eyal; Stevenson, William G; John, Roy M

    2013-01-01

    Catheter ablation has emerged as an important and effective treatment option for many recurrent ventricular arrhythmias. The approach to ablation and the risks and outcomes are largely determined by the nature of the severity and type of underlying heart disease. In patients with structural heart disease, catheter ablation can effectively reduce ventricular tachycardia (VT) episodes and implantable cardioverter defibrillator (ICD) shocks. For VT and symptomatic premature ventricular beats that occur in the absence of structural heart disease, catheter ablation is often effective as the sole therapy. Advances in catheter technology, imaging and mapping techniques have improved success rates for ablation. This review discusses current approaches to mapping and ablation for ventricular arrhythmias. PMID:26835040

  11. Central venous catheter - dressing change

    MedlinePlus

    ... will need: Sterile gloves Cleaning solution A special sponge A special patch, called a Biopatch A clear ... around the catheter. Clean the skin with the sponge and cleaning solution. Air dry after cleaning. Place ...

  12. Peripherally inserted central catheter - flushing

    MedlinePlus

    ... To flush your catheter, you will need: Clean paper towels Saline syringes (clear), and maybe heparin syringes (yellow) ... your fingers before washing. Dry with a clean paper towel. Set up your supplies on a clean surface ...

  13. 78 FR 33633 - Human Exposure to Radiofrequency Electromagnetic Fields

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-04

    ... to Radiofrequency Electromagnetic Fields; Reassessment of Exposure to Radiofrequency Electromagnetic..., and 95 Human Exposure to Radiofrequency Electromagnetic Fields AGENCY: Federal Communications... electromagnetic fields. More specifically, the Commission clarifies evaluation procedures and references...

  14. Comparison of cuffed tunneled hemodialysis catheter survival.

    PubMed

    Rocklin, M A; Dwight, C A; Callen, L J; Bispham, B Z; Spiegel, D M

    2001-03-01

    Despite efforts to have hemodialysis patients begin renal replacement therapy with a mature arteriovenous shunt, many patients begin dialysis with a cuffed tunneled catheter as their access. An increasing number of differently designed tunneled hemodialysis catheters have become available in the last decade. The primary aim of this study is to compare catheter survival for Hickman (Bard, Salt Lake City, UT) and Opti-flow (Bard) catheters. The 16-month experience with 182 catheters, totaling 13,861 catheter-days, is reported. The probability of Hickman catheter failure at 30, 60, and 90 days was 29%, 49%, and 67%. The probability of Opti-flow catheter failure was significantly less at 10%, 24%, and 38% for the same times, respectively (P: < 0.05 for all time points). The difference in catheter failure rates was caused by a greater malfunction rate of Hickman catheters; the two catheters had similar infection rates. We conclude that survival of Opti-flow catheters was significantly better than that of Hickman catheters from 30 to 90 days, which is a clinically relevant period when patients are waiting for maturation of a permanent access or replacement of a failed access. Since the conclusion of our study, we documented 10 episodes of Opti-flow catheter malfunction within 4 months secondary to hairline fracture of the arterial hub. The Opti-flow catheter was recalled and is now available with retooled hubs.

  15. Efficacy comparison between cryoablation and radiofrequency ablation for patients with cavotricuspid valve isthmus dependent atrial flutter: a meta-analysis

    NASA Astrophysics Data System (ADS)

    Chen, Yi-He; Lin, Hui; Xie, Cheng-Long; Zhang, Xiao-Ting; Li, Yi-Gang

    2015-06-01

    We perform this meta-analysis to compare the efficacy and safety of cryoablation versus radiofrequency ablation for patients with cavotricuspid valve isthmus dependent atrial flutter. By searching EMBASE, MEDLINE, PubMed and Cochrane electronic databases from March 1986 to September 2014, 7 randomized clinical trials were included. Acute (risk ratio[RR]: 0.93; P = 0.14) and long-term (RR: 0.94; P = 0.08) success rate were slightly lower in cryoablation group than in radiofrequency ablation group, but the difference was not statistically significant. Additionally, the fluoroscopy time was nonsignificantly reduced (weighted mean difference[WMD]: -2.83 P = 0.29), whereas procedure time was significantly longer (WMD: 25.95; P = 0.01) in cryoablation group compared with radiofrequency ablation group. Furthermore, Pain perception during the catheter ablation was substantially less in cryoabaltion group than in radiofrequency ablation group (standardized mean difference[SMD]: -2.36 P < 0.00001). Thus, our meta-analysis demonstrated that cryoablation and radiofrequency ablation produce comparable acute and long-term success rate for patients with cavotricuspid valve isthmus dependent atrial flutter. Meanwhile, cryoablation ablation tends to reduce the fluoroscopy time and significantly reduce pain perception in cost of significantly prolonged procedure time.

  16. Efficacy comparison between cryoablation and radiofrequency ablation for patients with cavotricuspid valve isthmus dependent atrial flutter: a meta-analysis

    PubMed Central

    Chen, Yi-He; Lin, Hui; Xie, Cheng-Long; Zhang, Xiao-Ting; Li, Yi-Gang

    2015-01-01

    We perform this meta-analysis to compare the efficacy and safety of cryoablation versus radiofrequency ablation for patients with cavotricuspid valve isthmus dependent atrial flutter. By searching EMBASE, MEDLINE, PubMed and Cochrane electronic databases from March 1986 to September 2014, 7 randomized clinical trials were included. Acute (risk ratio[RR]: 0.93; P = 0.14) and long-term (RR: 0.94; P = 0.08) success rate were slightly lower in cryoablation group than in radiofrequency ablation group, but the difference was not statistically significant. Additionally, the fluoroscopy time was nonsignificantly reduced (weighted mean difference[WMD]: −2.83; P = 0.29), whereas procedure time was significantly longer (WMD: 25.95; P = 0.01) in cryoablation group compared with radiofrequency ablation group. Furthermore, Pain perception during the catheter ablation was substantially less in cryoabaltion group than in radiofrequency ablation group (standardized mean difference[SMD]: −2.36; P < 0.00001). Thus, our meta-analysis demonstrated that cryoablation and radiofrequency ablation produce comparable acute and long-term success rate for patients with cavotricuspid valve isthmus dependent atrial flutter. Meanwhile, cryoablation ablation tends to reduce the fluoroscopy time and significantly reduce pain perception in cost of significantly prolonged procedure time. PMID:26039980

  17. Prospective study of peripheral arterial catheter infection and comparison with concurrently sited central venous catheters.

    PubMed

    Koh, David Boon Chai; Gowardman, John R; Rickard, Claire M; Robertson, Iain K; Brown, Andrew

    2008-02-01

    Peripheral arterial catheters are perceived as having low infective potential compared with other catheters and may be overlooked as a cause of catheter-related bloodstream infection. We aimed to measure colonization and rates of catheter-related bloodstream infection in arterial catheters, to investigate risk factors for arterial catheter colonization, and to compare arterial catheter infection rates with those in concurrently sited and managed central venous catheters. Prospective 24-month cohort study. Eight-bed combined general intensive care and high-dependency unit of a 350-bed Australian teaching hospital. Three hundred twenty-one arterial catheters in 252 adult and pediatric patients were observed for 1,082 catheter days, and 618 central venous catheters in 410 patients were observed for 4,040 catheter days. All catheters were inserted in, or presented to, the intensive care unit. Both arterial catheters and central venous catheters were inserted by trained personnel under aseptic conditions, and management was standardized. None. The incidence per 1,000 (95% confidence interval) catheter days of colonization (> or = 15 colonies) and catheter-related bloodstream infection was 15.7 (9.5-25.9) and 0.92 (0.13-6.44) for arterial catheters and 16.8 (13.3-21.3) and 2.23 (1.12-4.44) for central venous catheters. Arterial catheter colonization was not significantly different than that in central venous catheters (hazard ratio, 1.17; 95% confidence interval, 0.41-3.36; p = .77). Arterial catheter colonization increased with dwell time and was similar to central venous catheters over time. Femoral arterial catheters were colonized more often than radial arterial catheters (hazard ratio, 5.08; 95% confidence interval, 0.85, 30.3; p = .075), and colonization was significantly higher when the catheter was inserted in the operating theater or emergency department (hazard ratio, 4.45; 95% confidence interval, 1.42-13.9; p = .01) compared with the intensive care unit. The

  18. Intracorporeal knotting of a femoral nerve catheter.

    PubMed

    Ghanem, Mohamed; Schnoor, Jörg; Wiegel, Martin; Josten, Christoph; Reske, Andreas W

    2015-01-01

    Peripheral nerve catheters are effective and well-established tools to provide postoperative analgesia to patients undergoing orthopedic surgery. The performance of these techniques is usually considered safe. However, placement of nerve catheters may be associated with a considerable number of side effects and major complications have repeatedly been published. In this work, we report on a patient who underwent total knee replacement with spinal anesthesia and preoperative insertion of femoral and sciatic nerve catheters for postoperative analgesia. During insertion of the femoral catheter, significant resistance was encountered upon retracting the catheter. This occurred due to knotting of the catheter. The catheter had to be removed by operative intervention which has to be considered a major complication. The postoperative course was uneventful. The principles for removal of entrapped peripheral catheters are not well established, may differ from those for neuroaxial catheters, and range from cautious manipulation up to surgical intervention.

  19. Intracorporeal knotting of a femoral nerve catheter

    PubMed Central

    Ghanem, Mohamed; Schnoor, Jörg; Wiegel, Martin; Josten, Christoph; Reske, Andreas W.

    2015-01-01

    Peripheral nerve catheters are effective and well-established tools to provide postoperative analgesia to patients undergoing orthopedic surgery. The performance of these techniques is usually considered safe. However, placement of nerve catheters may be associated with a considerable number of side effects and major complications have repeatedly been published. In this work, we report on a patient who underwent total knee replacement with spinal anesthesia and preoperative insertion of femoral and sciatic nerve catheters for postoperative analgesia. During insertion of the femoral catheter, significant resistance was encountered upon retracting the catheter. This occurred due to knotting of the catheter. The catheter had to be removed by operative intervention which has to be considered a major complication. The postoperative course was uneventful. The principles for removal of entrapped peripheral catheters are not well established, may differ from those for neuroaxial catheters, and range from cautious manipulation up to surgical intervention. PMID:26504733

  20. Prevention and management of hemodialysis catheter infections.

    PubMed

    Ramanathan, Venkat; Darouiche, Rabih O

    2012-12-01

    Hemodialysis (HD) catheters are associated with blood stream infections, and catheter use continues to be high among incident and prevalent patients on maintenance HD. Migration of micro-organism along the external surface of the catheter is probably the most common route of infection, followed by the endoluminal route of contamination. Almost all HD catheters have biofilm formation on their surfaces and this serves as a good reservoir for micro-organisms. These active but protected microorganisms have been implicated in local and systemic infections associated with HD catheters. Good personal hygiene, exit-site care with topical antibiotics and antibiotic lock solution in the dialysis catheter reduce the incidence of catheter infection. In selected subgroup of patients, HD catheter is promptly removed after the diagnosis of blood stream infection. However, catheter guidewire exchange is an acceptable alternate strategy in some patients. The most important goal should be to increase the rate of incident arteriovenous fistula use in the HD population.

  1. Compensation for Unconstrained Catheter Shaft Motion in Cardiac Catheters

    PubMed Central

    Degirmenci, Alperen; Loschak, Paul M.; Tschabrunn, Cory M.; Anter, Elad; Howe, Robert D.

    2016-01-01

    Cardiac catheterization with ultrasound (US) imaging catheters provides real time US imaging from within the heart, but manually navigating a four degree of freedom (DOF) imaging catheter is difficult and requires extensive training. Existing work has demonstrated robotic catheter steering in constrained bench top environments. Closed-loop control in an unconstrained setting, such as patient vasculature, remains a significant challenge due to friction, backlash, and physiological disturbances. In this paper we present a new method for closed-loop control of the catheter tip that can accurately and robustly steer 4-DOF cardiac catheters and other flexible manipulators despite these effects. The performance of the system is demonstrated in a vasculature phantom and an in vivo porcine animal model. During bench top studies the robotic system converged to the desired US imager pose with sub-millimeter and sub-degree-level accuracy. During animal trials the system achieved 2.0 mm and 0.65° accuracy. Accurate and robust robotic navigation of flexible manipulators will enable enhanced visualization and treatment during procedures. PMID:27525170

  2. Model-based lasso catheter tracking in monoplane fluoroscopy for 3D breathing motion compensation during EP procedures

    NASA Astrophysics Data System (ADS)

    Liao, Rui

    2010-02-01

    Radio-frequency catheter ablation (RFCA) of the pulmonary veins (PVs) attached to the left atrium (LA) is usually carried out under fluoroscopy guidance. Overlay of detailed anatomical structures via 3-D CT and/or MR volumes onto the fluoroscopy helps visualization and navigation in electrophysiology procedures (EP). Unfortunately, respiratory motion may impair the utility of static overlay of the volume with fluoroscopy for catheter navigation. In this paper, we propose a B-spline based method for tracking the circumferential catheter (lasso catheter) in monoplane fluoroscopy. The tracked motion can be used for the estimation of the 3-D trajectory of breathing motion and for subsequent motion compensation. A lasso catheter is typically used during EP procedures and is pushed against the ostia of the PVs to be ablated. Hence this method does not require additional instruments, and achieves motion estimation right at the site of ablation. The performance of the proposed tracking algorithm was evaluated on 340 monoplane frames with an average error of 0.68 +/- 0.36 mms. Our contributions in this work are twofold. First and foremost, we show how to design an effective, practical, and workflow-friendly 3-D motion compensation scheme for EP procedures in a monoplane setup. In addition, we develop an efficient and accurate method for model-based tracking of the circumferential lasso catheter in the low-dose EP fluoroscopy.

  3. Endovascular Radiofrequency Ablation for Varicose Veins

    PubMed Central

    2011-01-01

    or worse as other chronic diseases such as back pain and arthritis. Lower limb VV is a very common disease affecting adults – estimated to be the 7th most common reason for physician referral in the US. There is a very strong familial predisposition to VV. The risk in offspring is 90% if both parents affected, 20% when neither affected and 45% (25% boys, 62% girls) if one parent affected. The prevalence of VV worldwide ranges from 5% to 15% among men and 3% to 29% among women varying by the age, gender and ethnicity of the study population, survey methods and disease definition and measurement. The annual incidence of VV estimated from the Framingham Study was reported to be 2.6% among women and 1.9% among men and did not vary within the age range (40-89 years) studied. Approximately 1% of the adult population has a stasis ulcer of venous origin at any one time with 4% at risk. The majority of leg ulcer patients are elderly with simple superficial vein reflux. Stasis ulcers are often lengthy medical problems and can last for several years and, despite effective compression therapy and multilayer bandaging are associated with high recurrence rates. Recent trials involving surgical treatment of superficial vein reflux have resulted in healing and significantly reduced recurrence rates. Endovascular Radiofrequency Ablation for Varicose Veins RFA is an image-guided minimally invasive treatment alternative to surgical stripping of superficial venous reflux. RFA does not require an operating room or general anaesthesia and has been performed in an outpatient setting by a variety of medical specialties including surgeons and interventional radiologists. Rather than surgically removing the vein, RFA works by destroying or ablating the refluxing vein segment using thermal energy delivered through a radiofrequency catheter. Prior to performing RFA, color-flow Doppler ultrasonography is used to confirm and map all areas of venous reflux to devise a safe and effective

  4. Ventricular Tachycardia Originating from Moderator Band: New Perspective on Catheter Ablation

    PubMed Central

    Li, Jin-yi; Jiang, Jing-bo; He, Yan; Luo, Jian-chun

    2017-01-01

    A 59-year-old woman was referred to the institution with burdens of idiopathic ventricular tachycardia (IVT). Electroanatomic mapping revealed a complex fractionated, high frequency potential with long duration preceding the QRS onset of the IVT. The real end point of ablation was the disappearance of the conduction block of Purkinje potential during the sinus rhythm besides the disappearance of the inducible tachycardia. Location of distal catheter was at the moderator band (MB) by transthoracic echocardiography (TTE). Only irrigated radiofrequency current was delivered at both insertions of the MB which can completely eliminate the IVT. PMID:28197345

  5. Predicting nurses' acceptance of radiofrequency identification technology.

    PubMed

    Norten, Adam

    2012-10-01

    The technology of radiofrequency identification allows for the scanning of radiofrequency identification-tagged objects and individuals without line-of-sight requirements. Healthcare organizations use radiofrequency identification to ensure the health and safety of patients and medical personnel and to uncover inefficiencies. Although the successful implementation of a system incorporating radiofrequency identification technologies requires acceptance and use of the technology, some nurses using radiofrequency identification in hospitals feel like "Big Brother" is watching them. This predictive study used a theoretical model assessing the effect of five independent variables: privacy concerns, attitudes, subjective norms, controllability, and self-efficacy, on a dependent variable, nurses' behavioral intention to use radiofrequency identification. A Web-based questionnaire containing previously validated questions was answered by 106 US RNs. Multiple linear regression showed that all constructs together accounted for 60% of the variance in nurses' intention to use radiofrequency identification. Of the predictors in the model, attitudes provided the largest unique contribution when the other predictors in the model were held constant; subjective norms also provided a unique contribution. Privacy concerns, controllability, and self-efficacy did not provide a significant contribution to nurses' behavioral intention to use radiofrequency identification.

  6. Evaluation of renal nerve morphological changes and norepinephrine levels following treatment with novel bipolar radiofrequency delivery systems in a porcine model

    PubMed Central

    Cohen-Mazor, Meital; Mathur, Prabodh; Stanley, James R.L.; Mendelsohn, Farrell O.; Lee, Henry; Baird, Rose; Zani, Brett G.; Markham, Peter M.; Rocha-Singh, Krishna

    2014-01-01

    Objective: To evaluate the safety and effectiveness of different bipolar radiofrequency system algorithms in interrupting the renal sympathetic nerves and reducing renal norepinephrine in a healthy porcine model. Methods: A porcine model (N = 46) was used to investigate renal norepinephrine levels and changes to renal artery tissues and nerves following percutaneous renal denervation with radiofrequency bipolar electrodes mounted on a balloon catheter. Parameters of the radiofrequency system (i.e. electrode length and energy delivery algorithm), and the effects of single and longitudinal treatments along the artery were studied with a 7-day model in which swine received unilateral radiofrequency treatments. Additional sets of animals were used to examine norepinephrine and histological changes 28 days following bilateral percutaneous radiofrequency treatment or surgical denervation; untreated swine were used for comparison of renal norepinephrine levels. Results: Seven days postprocedure, norepinephrine concentrations decreased proportionally to electrode length, with 81, 60 and 38% reductions (vs. contralateral control) using 16, 4 and 2-mm electrodes, respectively. Applying a temperature-control algorithm with the 4-mm electrodes increased efficacy, with a mean 89.5% norepinephrine reduction following a 30-s treatment at 68°C. Applying this treatment along the entire artery length affected more nerves vs. a single treatment, resulting in superior norepinephrine reduction 28 days following bilateral treatment. Conclusion: Percutaneous renal artery application of bipolar radiofrequency energy demonstrated safety and resulted in a significant renal norepinephrine content reduction and renal nerve injury compared with untreated controls in porcine models. PMID:24875181

  7. Reduction of Fluoroscopy Time and Radiation Dosage During Catheter Ablation for Atrial Fibrillation

    PubMed Central

    Aldhoon, Bashar; Kautzner, Josef

    2016-01-01

    Radiofrequency catheter ablation has become the treatment of choice for atrial fibrillation (AF) that does not respond to antiarrhythmic drug therapy. During the procedure, fluoroscopy imaging is still considered essential to visualise catheters in real-time. However, radiation is often ignored by physicians since it is invisible and the long-term risks are underestimated. In this respect, it must be emphasised that radiation exposure has various potentially harmful effects, such as acute skin injury, malignancies and genetic disease, both to patients and physicians. For this reason, every electrophysiologist should be aware of the problem and should learn how to decrease radiation exposure by both changing the setting of the system and using complementary imaging technologies. In this review, we aim to discuss the basics of X-ray exposure and suggest practical instructions for how to reduce radiation dosage during AF ablation procedures. PMID:27617094

  8. Materials for multifunctional balloon catheters with capabilities in cardiac electrophysiological mapping and ablation therapy

    NASA Astrophysics Data System (ADS)

    Kim, Dae-Hyeong; Lu, Nanshu; Ghaffari, Roozbeh; Kim, Yun-Soung; Lee, Stephen P.; Xu, Lizhi; Wu, Jian; Kim, Rak-Hwan; Song, Jizhou; Liu, Zhuangjian; Viventi, Jonathan; de Graff, Bassel; Elolampi, Brian; Mansour, Moussa; Slepian, Marvin J.; Hwang, Sukwon; Moss, Joshua D.; Won, Sang-Min; Huang, Younggang; Litt, Brian; Rogers, John A.

    2011-04-01

    Developing advanced surgical tools for minimally invasive procedures represents an activity of central importance to improving human health. A key challenge is in establishing biocompatible interfaces between the classes of semiconductor device and sensor technologies that might be most useful in this context and the soft, curvilinear surfaces of the body. This paper describes a solution based on materials that integrate directly with the thin elastic membranes of otherwise conventional balloon catheters, to provide diverse, multimodal functionality suitable for clinical use. As examples, we present sensors for measuring temperature, flow, tactile, optical and electrophysiological data, together with radiofrequency electrodes for controlled, local ablation of tissue. Use of such ‘instrumented’ balloon catheters in live animal models illustrates their operation, as well as their specific utility in cardiac ablation therapy. The same concepts can be applied to other substrates of interest, such as surgical gloves.

  9. Prevention of intravascular catheter-related infections.

    PubMed

    Mermel, L A

    2000-03-07

    To review the literature on prevention of intravascular catheter-related infections. The MEDLINE database, conference proceedings, and bibliographies of review articles and book chapters were searched for relevant articles. Primary authors were contacted directly if data were incomplete. Studies met the following criteria unless otherwise stated: Trials were prospective and randomized; catheters were inserted into new sites, not into old sites over guidewires; catheter cultures were done by using semi-quantitative or quantitative methods; and, for prospective studies, catheter-related bloodstream infection was confirmed by microbial growth from percutaneously drawn blood cultures that matched catheter cultures. Data on population, methods, preventive strategy, and outcome (measured as catheter-related bloodstream infections) were gathered. The quality of the data was graded by using preestablished criteria. The recommended preventive strategies with the strongest supportive evidence are full barrier precautions during central venous catheter insertion; subcutaneous tunneling short-term catheters inserted in the internal jugular or femoral veins when catheters are not used for drawing blood; contamination shields for pulmonary artery catheters; povidone-iodine ointment applied to insertion sites of hemodialysis catheters; specialized nursing teams caring for patients with short-term peripheral venous catheters, especially at institutions with a high incidence of catheter-related infection; no routine replacement of central venous catheters; antiseptic chamberfilled hub or hub-protective antiseptic sponge for central venous catheters; and use of chlorhexidine-silver sulfadiazine-impregnated or minocycline-rifampin-impregnated short-term central venous catheters if the rate of infection is high despite adherence to other strategies that do not incorporate antimicrobial agents (for example, maximal barrier precautions). Simple interventions can reduce the risk for

  10. Malfunctioning and infected tunneled infusion catheters: over-the-wire catheter exchange versus catheter removal and replacement.

    PubMed

    Guttmann, David M; Trerotola, Scott O; Clark, Timothy W; Dagli, Mandeep; Shlansky-Goldberg, Richard D; Itkin, Maxim; Soulen, Michael C; Mondschein, Jeffrey I; Stavropoulos, S William

    2011-05-01

    To compare the safety and effectiveness of over-the-wire catheter exchange (catheter-exchange) with catheter removal and replacement (removal-replacement) at a new site for infected or malfunctioning tunneled infusion catheters. Using a quality assurance database, 61 patients with tunneled infusion catheters placed during the period July 2001 to June 2009 were included in this study. Patients receiving hemodialysis catheters were excluded. Catheter-exchange was performed in 25 patients, and same-day removal-replacement was performed in 36 patients. Data collected included demographic information, indication for initial catheter placement and replacement, dwell time for the new catheter, and ultimate fate of the new device. Statistical comparisons between the two cohorts were analyzed using the Kaplan-Meier technique and Fisher exact test. Catheters exchanged over the wire remained functional without infection for a median of 102 days (range, 2-570 days), whereas catheters removed and replaced were functional for a median 238 days (range, 1-292 days, P = .12). After catheter replacement, there were 11 instances of subsequent infection in the catheter-exchange group and 7 instances in the removal-replacement cohort, accounting for infection rates of 4.4 and 2.3 per 1,000 catheter days (P = .049). Patients in the catheter-exchange group had 3.2 greater odds of infection compared with patients in the removal-replacement group. Five malfunction events occurred in each group, accounting for 2.0 and 1.7 malfunctions per 1,000 catheter days in the catheter-exchange and removal-replacement groups (P = .73). Catheter-exchange of tunneled infusion catheters results in a higher infection rate compared with removal-replacement at a new site. The rate of catheter malfunction is not significantly different between the two groups. Catheter-exchange is an alternative for patients with tunneled infusion catheters who have limited venous access, but this technique should not be

  11. Aesthetic Applications of Radiofrequency Devices.

    PubMed

    Sadick, Neil; Rothaus, Kenneth O

    2016-07-01

    Radiofrequency (RF)-based devices are used to improve face and neck laxity, a major feature of aging that until recently could only be addressed with surgery. Although these treatments are not meant to replace surgical procedures, patient satisfaction studies have been consistently high. For physicians offering these skin rejuvenation procedures, it is essential to have intimate knowledge of how the devices work, select appropriate candidates, set realistic expectations, and combine treatments to optimize outcomes. This article discusses the various noninvasive RF technologies currently in use and reviews pertinent clinical studies evaluating their efficacy and safety. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Lumbar and sacral radiofrequency neurotomy.

    PubMed

    Mazin, David A; Sullivan, Joseph P

    2010-11-01

    Radiofrequency (RF) neurotomy is an interventional procedure used to alleviate certain types of low back pain. RF energy is used to thermally coagulate the specific nerves that transmit pain signals. Recent evidence has shown that this procedure demonstrates significant efficacy in relieving low back pain in lumbar zygapophysial joints, and research is ongoing to determine if pain relief for the sacroiliac joint is also possible. This article provides an evidence-based background for performing RF neurotomy, discusses the relevant anatomy, and highlights the indications and technique for lumbar and sacral RF neurotomy. Copyright © 2010 Elsevier Inc. All rights reserved.

  13. Radio-Frequency Strain Monitor

    NASA Technical Reports Server (NTRS)

    Heyman, Joseph S.; Rogowski, Robert S.; Holben, Milford S., Jr.

    1988-01-01

    Radio-frequency (RF) strain monitor developed to measure lengths of objects. RF waveguide or cable bonded to structure monitored. Propagation of RF signal along waveguide results in phase shift proportional to length of path traveled. Impedance mismatches placed in RF cable at nodes of structure. Records mismatches and detects overall length of line and lengths of intervals between nodes. Used to detect changes in elements of large structure with single cable. Monitor has potential for many applications, including monitoring stability of such large structures as aircraft, bridges, and buildings in Earthquake zones.

  14. Laser Navigation for Radiofrequency Ablation

    SciTech Connect

    Varro, Zoltan; Locklin, Julia K. Wood, Bradford J.

    2004-09-15

    A 45-year-old male with renal cell carcinoma secondary to von-Hippel Lindau (VHL) disease presented for radiofrequency ablation (RFA) of kidney tumors. Due to his prior history of several partial nephrectomies and limited renal reserve, RFA was chosen because of its relatively nephron-sparing nature. A laser guidance device was used to help guide probe placement in an attempt to reduce procedure time and improve targeting accuracy. The device was successful at guiding needle placement, as both tumors were located with a single pass. Follow-up CT scan confirmed accurate needle placement, showing an area of coagulation necrosis covering the previously seen tumor.

  15. Radiofrequency Ablation for Liver Cancer.

    PubMed

    Jacobs, Amy

    2015-01-01

    Interventional ablative technologies aided by imaging techniques such as ultrasonography, computed tomography, and magnetic resonance imaging have been crucial in managing patients with primary liver cancer and liver metastases over the past 20 years. Several ablative technologies have been used to treat liver cancer; however, radiofrequency ablation (RFA) has emerged as the most common ablative therapy for hepatic lesions, both in the United States and globally. RFA is the treatment of choice for patients who cannot have surgical resection of the liver. This article focuses on the role of imaging in RFA treatment of primary and metastatic hepatic lesions.

  16. Catheter-based photoacoustic endoscope

    PubMed Central

    Yang, Joon-Mo; Li, Chiye; Chen, Ruimin; Zhou, Qifa; Shung, K. Kirk; Wang, Lihong V.

    2014-01-01

    Abstract. We report a flexible shaft-based mechanical scanning photoacoustic endoscopy (PAE) system that can be potentially used for imaging the human gastrointestinal tract via the instrument channel of a clinical video endoscope. The development of such a catheter endoscope has been an important challenge to realize the technique’s benefits in clinical settings. We successfully implemented a prototype PAE system that has a 3.2-mm diameter and 2.5-m long catheter section. As the instrument’s flexible shaft and scanning tip are fully encapsulated in a plastic catheter, it easily fits within the 3.7-mm diameter instrument channel of a clinical video endoscope. Here, we demonstrate the intra-instrument channel workability and in vivo animal imaging capability of the PAE system. PMID:24887743

  17. Catheter-based photoacoustic endoscope

    NASA Astrophysics Data System (ADS)

    Yang, Joon-Mo; Li, Chiye; Chen, Ruimin; Zhou, Qifa; Shung, K. Kirk; Wang, Lihong V.

    2014-06-01

    We report a flexible shaft-based mechanical scanning photoacoustic endoscopy (PAE) system that can be potentially used for imaging the human gastrointestinal tract via the instrument channel of a clinical video endoscope. The development of such a catheter endoscope has been an important challenge to realize the technique's benefits in clinical settings. We successfully implemented a prototype PAE system that has a 3.2-mm diameter and 2.5-m long catheter section. As the instrument's flexible shaft and scanning tip are fully encapsulated in a plastic catheter, it easily fits within the 3.7-mm diameter instrument channel of a clinical video endoscope. Here, we demonstrate the intra-instrument channel workability and in vivo animal imaging capability of the PAE system.

  18. Steam pops during irrigated radiofrequency ablation: feasibility of impedance monitoring for prevention.

    PubMed

    Seiler, Jens; Roberts-Thomson, Kurt C; Raymond, Jean-Marc; Vest, John; Delacretaz, Etienne; Stevenson, William G

    2008-10-01

    Steam pops are a risk of irrigated radiofrequency catheter ablation (RFA) and may cause cardiac perforation. Data to guide radiofrequency (RF) energy titration to avoid steam pops are limited. This study sought to assess the frequency and consequence of audible pops and to determine the feasibility of using the magnitude of impedance change to predict pops. We reviewed consecutive endocardial open-irrigated RFA for ventricular tachycardia (VT) with continuously recorded ablation data in 142 patients with structural heart disease. Steam pops were defined as an audible pop associated with a sudden spike in impedance. Ablation lesions before or after pops served as controls. From a total of 4,107 ablation lesions, 62 (1.5%) steam pops occurred in 42 procedures in 38 patients. Perforation with tamponade occurred with 1 of 62 (2%) pops. Applications with pops had a greater impedance decrease (22 +/- 7 Omega vs. 18 +/- 8 Omega, P = .001) and a higher maximum power (45 +/- 5 W vs. 43 +/- 6 W, P = .011), but did not differ in maximum catheter tip temperature (40 degrees C +/- 4 degrees C vs. 40 degrees C +/- 4 degrees C, P = .180) from applications without pops. Eighty percent of pops occurred after impedance decreased by at least 18 Omega. During VT ablation with open irrigation, audible pops are infrequent and do not usually cause perforation. Limiting RF power to achieve an impedance decrease of <18 Omega is a feasible method of reducing the likelihood of a pop when perforation risk is of concern.

  19. [The radiofrequency ablation of accessory pathways in 100 consecutive patients with supraventricular tachycardias].

    PubMed

    Colín, L; Kershenovich, S; Iturralde, P; Dan, L; Martínez Ríos, M A; Casanova, M; González Hermosillo, J A

    1993-01-01

    The purpose of this study is to describe the results and the complications of radiofrequency catheter ablation, of accessory pathways in 100 consecutive patients. We had one patient with two pathways. Of the 101 accessory pathways, 56 were overt and 45 concealed. Only 19 patients have had a previous electrophysiology study, in the others, the study and the ablation were performed simultaneously. The location of the accessory pathways were as follows: 61 pathways in the free wall of the left ventricle, 4 in the free wall of the right ventricle, 25 in the left posteroseptal region, 9 in the right posteroseptal region and 2 in the right anteroseptal area. The time required for the diagnostic component of the electrophysiology study, the ablation procedure and the fluoroscopic time was recorded for each patient. Ninety-one of 101 accessory AV connections were successfully ablated (90%). Our success rate for the initial attempt was 87%. We had the opportunity to do a second attempt in only 4 out of 14 patients. The mean time of the procedure, including the electrophysiology test and the ablation was 95.6 %/-55.3 minutes. We have had a recurrence of 9% and 4% of non fatal complications. Radiofrequency catheter ablation can be performed safely and with a high success rate.

  20. Safeguards May Be Reducing Serious Catheter Infections

    MedlinePlus

    ... They include using sterile gloves, covering catheters with antimicrobial dressings and checking catheters daily for signs of movement or infection. Many hospitals have also added extra training, equipment and supplies. For this study, Nuckols and her colleagues analyzed ...

  1. Cardiac ablation catheter guidance by means of a single equivalent moving dipole inverse algorithm.

    PubMed

    Lee, Kichang; Lv, Wener; Ter-Ovanesyan, Evgeny; Barley, Maya E; Voysey, Graham E; Galea, Anna M; Hirschman, Gordon B; Leroy, Kristen; Marini, Robert P; Barrett, Conor; Armoundas, Antonis A; Cohen, Richard J

    2013-07-01

    We developed and evaluated a novel system for guiding radiofrequency catheter ablation therapy of ventricular tachycardia. This guidance system employs an inverse solution guidance algorithm (ISGA) using a single equivalent moving dipole (SEMD) localization method. The method and system were evaluated in both a saline tank phantom model and in vivo animal (swine) experiments. A catheter with two platinum electrodes spaced 3 mm apart was used as the dipole source in the phantom study. A 40-Hz sinusoidal signal was applied to the electrode pair. In the animal study, four to eight electrodes were sutured onto the right ventricle. These electrodes were connected to a stimulus generator delivering 1-ms duration pacing pulses. Signals were recorded from 64 electrodes, located either on the inner surface of the saline tank or on the body surface of the pig, and then processed by the ISGA to localize the physical or bioelectrical SEMD. In the phantom studies, the guidance algorithm was used to advance a catheter tip to the location of the source dipole. The distance from the final position of the catheter tip to the position of the target dipole was 2.22 ± 0.78 mm in real space and 1.38 ± 0.78 mm in image space (computational space). The ISGA successfully tracked the locations of electrodes sutured on the ventricular myocardium and the movement of an endocardial catheter placed in the animal's right ventricle. In conclusion, we successfully demonstrated the feasibility of using an SEMD inverse algorithm to guide a cardiac ablation catheter. ©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.

  2. MEMS-Based Flexible Force Sensor for Tri-Axial Catheter Contact Force Measurement.

    PubMed

    Pandya, Hardik J; Sheng, Jun; Desai, Jaydev P

    2017-02-01

    Atrial fibrillation (AFib) is a significant healthcare problem caused by the uneven and rapid discharge of electrical signals from pulmonary veins (PVs). The technique of radiofrequency (RF) ablation can block these abnormal electrical signals by ablating myocardial sleeves inside PVs. Catheter contact force measurement during RF ablation can reduce the rate of AFib recurrence, since it helps to determine effective contact of the catheter with the tissue, thereby resulting in effective power delivery for ablation. This paper presents the development of a three-dimensional (3D) force sensor to provide the real-time measurement of tri-axial catheter contact force. The 3D force sensor consists of a plastic cubic bead and five flexible force sensors. Each flexible force sensor was made of a PEDOT:PSS strain gauge and a PDMS bump on a flexible PDMS substrate. Calibration results show that the fabricated sensor has a linear response in the force range required for RF ablation. To evaluate its working performance, the fabricated sensor was pressed against gelatin tissue by a micromanipulator and also integrated on a catheter tip to test it within deionized water flow. Both experiments simulated the ventricular environment and proved the validity of applying the 3D force sensor in RF ablation.

  3. Left atrial function and scar after catheter ablation of atrial fibrillation.

    PubMed

    Wylie, John V; Peters, Dana C; Essebag, Vidal; Manning, Warren J; Josephson, Mark E; Hauser, Thomas H

    2008-05-01

    Catheter ablation of atrial fibrillation (AF) involves extensive radiofrequency ablation (RFA) of the left atrium (LA) around the pulmonary veins. The effect of this therapy on LA function is not fully characterized. The purpose of this study was to determine whether catheter ablation of AF is associated with a change in LA function. LA and right atrial (RA) systolic function was assessed in 33 consecutive patients with paroxysmal or persistent AF referred for ablation using cardiovascular magnetic resonance (CMR) imaging. Steady-state free precession ECG cine CMR imaging was performed before and after (mean 48 days) AF ablation. All patients underwent circumferential pulmonary vein isolation using an 8-mm tip RFA catheter. High spatial resolution late gadolinium enhancement CMR images of LA scar were obtained in 16 patients. Maximum LA volume decreased by 15% (P <.001), and LA ejection fraction decreased by 14% (P <.001) after AF ablation. Maximum RA volume decreased by 13% (P = .018), but RA ejection fraction increased by 5% (P = .008). Mean LA scar volume was 8.1 +/- 3.7 mL. A linear correlation was observed between change in LA ejection fraction and scar volume (r = -0.75, P <.001). Catheter ablation of AF is associated with decreased LA size and reduced atrial systolic function. This change strongly correlates with the volume of LA scar. This finding may have implications for postprocedural thromboembolic risk and for procedures involving more extensive RFA.

  4. Respiratory motion influence on catheter contact force during radio frequency ablation procedures

    NASA Astrophysics Data System (ADS)

    Koch, Martin; Brost, Alexander; Hornegger, Joachim; Strobel, Norbert

    2013-03-01

    Minimally invasive catheter ablation is a common treatment option for atrial fibrillation. A common treatment strategy is pulmonary vein isolation. In this case, individual ablation points need to be placed around the ostia of the pulmonary veins attached to the left atrium to generate transmural lesions and thereby block electric signals. To achieve a durable transmural lesion, the tip of the catheter has to be stable with a sufficient tissue contact during radio-frequency ablation. Besides the steerable interface operated by the physician, the movement of the catheter is also influenced by the heart and breathing motion - particularly during ablation. In this paper we investigate the influence of breathing motion on different areas of the endocardium during radio frequency ablation. To this end, we analyze the frequency spectrum of the continuous catheter contact force to identify areas with increased breathing motion using a classification method. This approach has been applied to clinical patient data acquired during three pulmonary vein isolation procedures. Initial findings show that motion due to respiration is more pronounced at the roof and around the right pulmonary veins.

  5. Catheter-based cryoablation of atrial fibrillation: state of the art.

    PubMed

    Klein, G; Gardiwal, A; Oswald, H

    2008-12-01

    Catheter-based ablation has been adopted as second-line therapy for both paroxysmal and persistent atrial fibrillation (AF) and is currently investigated as a primary approach. Reported success rates of catheter-based radiofrequency (RF) ablation vary between 65% and 85% depending on the technique used, patient selection and experience of the center. However, catheter ablation of AF is not without risk. In a worldwide survey major complications were reported in up to 6% of the procedures. Also, in high volume centers a complication rate of 5% is reported, which declined after excluding the learning curve during the first 100 procedures to 4.3%. These complications and the observation that AF-ablation using RF-energy is a demanding procedure in terms of operator competency and dexterity limiting the world-wide availability of this therapy lead to an extensive search for alternative energy and delivery sources. In four studies from Europe the new cryoballoon approach is effective and safe and appears to have a similar success rate than RF-ablation at least in paroxysmal AF and normally sized left atria. Changes in catheter design and additional equipment will probably improve this technique. Further clinical studies should focus on a head-to-head comparison between cryoablation and RF-ablation in AF. The favou-rable risk profile of cryoenergy might pave the way for cryoballoon ablation as a first-line treatment option in patients with paroxysmal AF.

  6. Interventional magnetic resonance angiography with no strings attached: wireless active catheter visualization.

    PubMed

    Quick, Harald H; Zenge, Michael O; Kuehl, Hilmar; Kaiser, Gernot; Aker, Stephanie; Massing, Sandra; Bosk, Silke; Ladd, Mark E

    2005-02-01

    Active instrument visualization strategies for interventional MR angiography (MRA) require vascular instruments to be equipped with some type of radiofrequency (RF) coil or dipole RF antenna for MR signal detection. Such visualization strategies traditionally necessitate a connection to the scanner with either coaxial cable or laser fibers. In order to eliminate any wire connection, RF resonators that inductively couple their signal to MR surface coils were implemented into catheters to enable wireless active instrument visualization. Instrument background to contrast-to-noise ratio was systematically investigated as a function of the excitation flip angle. Signal coupling between the catheter RF coil and surface RF coils was evaluated qualitatively and quantitatively as a function of the catheter position and orientation with regard to the static magnetic field B0 and to the surface coils. In vivo evaluation of the instruments was performed in interventional MRA procedures on five pigs under MR guidance. Cartesian and projection reconstruction TrueFISP imaging enabled simultaneous visualization of the instruments and vascular morphology in real time. The implementation of RF resonators enabled robust visualization of the catheter curvature to the very tip. Additionally, the active visualization strategy does not require any wire connection to the scanner and thus does not hamper the interventionalist during the course of an intervention.

  7. First In Vivo Use of a Capacitive Micromachined Ultrasound Transducer Array–Based Imaging and Ablation Catheter

    PubMed Central

    Stephens, Douglas N.; Truong, Uyen T.; Nikoozadeh, Amin; Oralkan, Ömer; Seo, Chi Hyung; Cannata, Jonathan; Dentinger, Aaron; Thomenius, Kai; de la Rama, Alan; Nguyen, Tho; Lin, Feng; Khuri-Yakub, Pierre; Mahajan, Aman; Shivkumar, Kalyanam; O’Donnell, Matt; Sahn, David J.

    2012-01-01

    Objectives The primary objective was to test in vivo for the first time the general operation of a new multifunctional intracardiac echocardiography (ICE) catheter constructed with a microlinear capacitive micromachined ultrasound transducer (ML-CMUT) imaging array. Secondarily, we examined the compatibility of this catheter with electroanatomic mapping (EAM) guidance and also as a radiofrequency ablation (RFA) catheter. Preliminary thermal strain imaging (TSI)-derived temperature data were obtained from within the endocardium simultaneously during RFA to show the feasibility of direct ablation guidance procedures. Methods The new 9F forward-looking ICE catheter was constructed with 3 complementary technologies: a CMUT imaging array with a custom electronic array buffer, catheter surface electrodes for EAM guidance, and a special ablation tip, that permits simultaneous TSI and RFA. In vivo imaging studies of 5 anesthetized porcine models with 5 CMUT catheters were performed. Results The ML-CMUT ICE catheter provided high-resolution real-time wideband 2-dimensional (2D) images at greater than 8 MHz and is capable of both RFA and EAM guidance. Although the 24-element array aperture dimension is only 1.5 mm, the imaging depth of penetration is greater than 30 mm. The specially designed ultrasound-compatible metalized plastic tip allowed simultaneous imaging during ablation and direct acquisition of TSI data for tissue ablation temperatures. Postprocessing analysis showed a first-order correlation between TSI and temperature, permitting early development temperature-time relationships at specific myocardial ablation sites. Conclusions Multifunctional forward-looking ML-CMUT ICE catheters, with simultaneous intracardiac guidance, ultrasound imaging, and RFA, may offer a new means to improve interventional ablation procedures. PMID:22298868

  8. First in vivo use of a capacitive micromachined ultrasound transducer array-based imaging and ablation catheter.

    PubMed

    Stephens, Douglas N; Truong, Uyen T; Nikoozadeh, Amin; Oralkan, Omer; Seo, Chi Hyung; Cannata, Jonathan; Dentinger, Aaron; Thomenius, Kai; de la Rama, Alan; Nguyen, Tho; Lin, Feng; Khuri-Yakub, Pierre; Mahajan, Aman; Shivkumar, Kalyanam; O'Donnell, Matt; Sahn, David J

    2012-02-01

    The primary objective was to test in vivo for the first time the general operation of a new multifunctional intracardiac echocardiography (ICE) catheter constructed with a microlinear capacitive micromachined ultrasound transducer (ML-CMUT) imaging array. Secondarily, we examined the compatibility of this catheter with electroanatomic mapping (EAM) guidance and also as a radiofrequency ablation (RFA) catheter. Preliminary thermal strain imaging (TSI)-derived temperature data were obtained from within the endocardium simultaneously during RFA to show the feasibility of direct ablation guidance procedures. The new 9F forward-looking ICE catheter was constructed with 3 complementary technologies: a CMUT imaging array with a custom electronic array buffer, catheter surface electrodes for EAM guidance, and a special ablation tip, that permits simultaneous TSI and RFA. In vivo imaging studies of 5 anesthetized porcine models with 5 CMUT catheters were performed. The ML-CMUT ICE catheter provided high-resolution real-time wideband 2-dimensional (2D) images at greater than 8 MHz and is capable of both RFA and EAM guidance. Although the 24-element array aperture dimension is only 1.5 mm, the imaging depth of penetration is greater than 30 mm. The specially designed ultrasound-compatible metalized plastic tip allowed simultaneous imaging during ablation and direct acquisition of TSI data for tissue ablation temperatures. Postprocessing analysis showed a first-order correlation between TSI and temperature, permitting early development temperature-time relationships at specific myocardial ablation sites. Multifunctional forward-looking ML-CMUT ICE catheters, with simultaneous intracardiac guidance, ultrasound imaging, and RFA, may offer a new means to improve interventional ablation procedures.

  9. Hemodialysis Tunneled Catheter-Related Infections

    PubMed Central

    Miller, Lisa M.; Clark, Edward; Dipchand, Christine; Hiremath, Swapnil; Kappel, Joanne; Kiaii, Mercedeh; Lok, Charmaine; Luscombe, Rick; Moist, Louise; Oliver, Matthew; MacRae, Jennifer

    2016-01-01

    Catheter-related bloodstream infections, exit-site infections, and tunnel infections are common complications related to hemodialysis central venous catheter use. The various definitions of catheter-related infections are reviewed, and various preventive strategies are discussed. Treatment options, for both empiric and definitive infections, including antibiotic locks and systemic antibiotics, are reviewed. PMID:28270921

  10. 21 CFR 870.1280 - Steerable catheter.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Steerable catheter. 870.1280 Section 870.1280 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1280 Steerable catheter. (a) Identification. A steerable catheter is...

  11. 21 CFR 874.4175 - Nasopharyngeal catheter.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Surgical Devices § 874.4175 Nasopharyngeal catheter. (a) Identification. A nasopharyngeal catheter is a device consisting of a bougie or filiform catheter that is intended for use in probing or dilating the eustachian tube. This generic type of device...

  12. 21 CFR 874.4175 - Nasopharyngeal catheter.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Surgical Devices § 874.4175 Nasopharyngeal catheter. (a) Identification. A nasopharyngeal catheter is a device consisting of a bougie or filiform catheter that is intended for use in probing or dilating the eustachian tube. This generic type of device...

  13. Short- and long-term effects of transcatheter ablation of the coronary sinus by radiofrequency energy

    SciTech Connect

    Huang, S.K.; Graham, A.R.; Bharati, S.; Lee, M.A.; Gorman, G.; Lev, M.

    1988-08-01

    Catheter ablation of left-sided atrioventricular accessory pathways through the coronary sinus by direct-current shock may be complicated by rupture and thrombosis of the coronary sinus and injury to the coronary arteries. This study examined short and long-term effects of radiofrequency catheter ablation of the coronary sinus in 20 closed-chest dogs to determine whether this technique is feasible for potential interruption of left-sided accessory pathways. Single-pulsed radiofrequency energy (750 kHz, 85-293 J) was delivered to three sites in the distal and middle coronary sinus between the distal (1) or the proximal electrodes (2 or 3) of a standard 6 French quadripolar catheter and a chest-wall patch electrode. Single-pulsed radiofrequency energy (78-293 J) was also applied to two sites near the ostium of the coronary sinus with the proximal (4) or the distal (1) electrode of the same catheter. Coronary artery and levophase coronary sinus angiograms obtained before and immediately after ablation, as well as before killing, showed intact vascular structures in all dogs. Right atrial, pulmonary arterial, and aortic pressures measured in three dogs did not change significantly at the time of energy delivery. No significant changes were found in atrioventricular nodal refractoriness and conduction. None of the dogs had significant rhythm disturbances during and after ablation as evaluated by ambulatory electrocardiographic monitoring and periodic rhythm strips at follow-up. Ten dogs were killed 1-7 days after ablation, three dogs were killed at 4 weeks, three dogs at 6 weeks, two dogs at 8 weeks, and two dogs at 12 weeks. Discrete lesions ranging in size from 3 x 3 to 8 x 10 mm2 in surface area and 0.5-4.5 mm in depth were found in the coronary sinus with most of the lesions extending to the left atrial and left ventricular myocardium. There was neither rupture of the coronary sinus nor occlusion of the coronary arteries.

  14. Percutaneous Intraductal Radiofrequency Ablation is a Safe Treatment for Malignant Biliary Obstruction: Feasibility and Early Results

    SciTech Connect

    Mizandari, Malkhaz; Pai, Madhava Xi Feng; Valek, Vlastimil; Tomas, Andrasina; Quaretti, Pietro; Golfieri, Rita; Mosconi, Cristina; Ao Guokun; Kyriakides, Charis; Dickinson, Robert; Nicholls, Joanna; Habib, Nagy

    2013-06-15

    Purpose. Previous clinical studies have shown the safety and efficacy of this novel radiofrequency ablation catheter when used for endoscopic palliative procedures. We report a retrospective study with the results of first in man percutaneous intraductal radiofrequency ablation in patients with malignant biliary obstruction. Methods. Thirty-nine patients with inoperable malignant biliary obstruction were included. These patients underwent intraductal biliary radiofrequency ablation of their malignant biliary strictures following external biliary decompression with an internal-external biliary drainage. Following ablation, they had a metal stent inserted. Results. Following this intervention, there were no 30-day mortality, hemorrhage, bile duct perforation, bile leak, or pancreatitis. Of the 39 patients, 28 are alive and 10 patients are dead with a median survival of 89.5 (range 14-260) days and median stent patency of 84.5 (range 14-260) days. One patient was lost to follow-up. All but one patient had their stent patent at the time of last follow-up or death. One patient with stent blockage at 42 days postprocedure underwent percutaneous transhepatic drain insertion and restenting. Among the patients who are alive (n = 28) the median stent patency was 92 (range 14-260) days, whereas the patients who died (n = 10) had a median stent patency of 62.5 (range 38-210) days. Conclusions. In this group of patients, it appears that this new approach is feasible and safe. Efficacy remains to be proven in future, randomized, prospective studies.

  15. Effectiveness of different central venous catheters for catheter-related infections: a network meta-analysis.

    PubMed

    Wang, H; Huang, T; Jing, J; Jin, J; Wang, P; Yang, M; Cui, W; Zheng, Y; Shen, H

    2010-09-01

    We aimed to compare the effectiveness of various catheters for prevention of catheter-related infection and to evaluate whether specific catheters are superior to others for reducing catheter-related infections. We identified randomised, controlled trials that compared different types of central venous catheter (CVC), evaluating catheter-related infections in a systematic search of articles published from January 1996 to November 2009 via Medline, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials. Network meta-analysis with a mixed treatment comparison method using Bayesian Markov Chain Monte Carlo simulation was used to combine direct within-trial, between-treatment comparisons with indirect trial evidence. Forty-eight clinical trials (12 828 CVCs) investigating 10 intervention catheters contributed to the analyses. For prevention of CVC colonisation, adjusted silver iontophoretic catheters (odds ratio: 0.58; 95% confidence interval: 0.33-0.95), chlorhexidine and silver sulfadiazine catheters (0.49; 0.36-0.64), chlorhexidine and silver sulfadiazine blue plus catheters (0.37; 0.17-0.69), minocycline-rifampicin catheters (0.28; 0.17-0.43) and miconazole-rifampicin catheters (0.11; 0.02-0.33) were associated with a significantly lower rate of catheter colonisation compared with standard catheters. For prevention of CRBSI, adjusted heparin-bonded catheters (0.20; 0.06-0.44) and minocycline-rifampicin catheters (0.18; 0.08-0.34) were associated with a significantly lower rate of CRBSI with standard catheters. Rifampicin-based impregnated catheters seem to be better for prevention of catheter-related infection compared with the other catheters.

  16. Cytometric Catheter for Neurosurgical Applications

    SciTech Connect

    Evans III, Boyd Mccutchen; Allison, Stephen W; Fillmore, Helen; Broaddus, William C; Dyer, Rachel L; Gillies, George

    2010-01-01

    Implantation of neural progenitor cells into the central nervous system has attracted strong interest for treatment of a variety of pathologies. For example, the replacement of dopamine-producing (DA) neural cells in the brain appears promising for the treatment of patients affected by Parkinson's disease. Previous studies of cell-replacement strategies have shown that less than 90% of implanted cells survive longer than 24 - 48 hours following the implantation procedure. However, it is unknown if these cells were viable upon delivery, or if they were affected by other factors such as brain pathology or an immune response. An instrumented cell-delivery catheter has been developed to assist in answering these questions by facilitating quantification and monitoring of the viability of the cells delivered. The catheter uses a fiber optic probe to perform flourescence-based cytometric measurments on cells exiting the port at the catheter tip. The current implementation of this design is on a 3.2 mm diameter catheter with 245 micrometer diameter optical fibers. Results of fluorescence testing data are presented and show that the device can characterize the quantity of cell densities ranging from 60,000 cells/ml to 600,000 cells/ml with a coefficient of determination of 0.93.

  17. Catheter-related bloodstream infections

    PubMed Central

    Gahlot, Rupam; Nigam, Chaitanya; Kumar, Vikas; Yadav, Ghanshyam; Anupurba, Shampa

    2014-01-01

    Central-venous-catheter-related bloodstream infections (CRBSIs) are an important cause of hospital-acquired infection associated with morbidity, mortality, and cost. Consequences depend on associated organisms, underlying pre-morbid conditions, timeliness, and appropriateness of the treatment/interventions received. We have summarized risk factors, pathogenesis, etiology, diagnosis, and management of CRBSI in this review. PMID:25024944

  18. Patency and complications of translumbar dialysis catheters

    PubMed Central

    Liu, Fanna; Bennett, Stacy; Arrigain, Susana; Schold, Jesse; Heyka, Robert; McLennan, Gordon; Navaneethan, Sankar D.

    2016-01-01

    Background Translumbar tunneled dialysis catheter (TLDC) is a temporary dialysis access for patients exhausted traditional access for dialysis. While few small studies reported successes with TLDC, additional studies are warranted to understand the short and long-term patency and safety of TLDC. Methods We conducted a retrospective analysis of adult patients who received TLDC for hemodialysis access from June 2006 to June 2013. Patient demographics, comorbid conditions, dialysis details, catheter insertion procedures and associated complications, catheter patency, and patient survival data were collected. Catheter patency was studied using Kaplan-Meier curve; catheter functionality was assessed with catheter intervals and catheter related complications were used to estimate catheter safety. Results There were 84 TLDCs inserted in 28 patients with 28 primary insertions and 56 exchanges. All TLDC insertions were technically successful with good blood flow during dialysis (>300 ml/min) and no immediate complications (major bleeding or clotting) were noted. The median number of days in place for initial catheter, secondary catheter and total catheter were 65, 84 and 244 respectively. The catheter patency rate at 3, 6 and 12 months were 43%, 25% and 7% respectively. The main complications were poor blood flow (40%) and catheter related infection (36%), which led to 30.8% and 35.9% catheter removal respectively. After translumbar catheter, 42.8% of the patients were successfully converted to another vascular access or peritoneal dialysis. Conclusion This study data suggests that TLDC might serve as a safe, alternate access for dialysis patients in short-term who have exhausted conventional vascular access. PMID:25800550

  19. Patency and Complications of Translumbar Dialysis Catheters.

    PubMed

    Liu, Fanna; Bennett, Stacy; Arrigain, Susana; Schold, Jesse; Heyka, Robert; McLennan, Gordon; Navaneethan, Sankar D

    2015-01-01

    Translumbar tunneled dialysis catheter (TLDC) is a temporary dialysis access for patients exhausted traditional access for dialysis. While few small studies reported successes with TLDC, additional studies are warranted to understand the short- and long-term patency and safety of TLDC. We conducted a retrospective analysis of adult patients who received TLDC for hemodialysis access from June 2006 to June 2013. Patient demographics, comorbid conditions, dialysis details, catheter insertion procedures and associated complications, catheter patency, and patient survival data were collected. Catheter patency was studied using Kaplan-Meier curve; catheter functionality was assessed with catheter intervals and catheter-related complications were used to estimate catheter safety. There were 84 TLDCs inserted in 28 patients with 28 primary insertions and 56 exchanges. All TLDC insertions were technically successful with good blood flow during dialysis (>300 ml/minute) and no immediate complications (major bleeding or clotting) were noted. The median number of days in place for initial catheter, secondary catheter, and total catheter were 65, 84, and 244 respectively. The catheter patency rate at 3, 6, and 12 months were 43%, 25%, and 7% respectively. The main complications were poor blood flow (40%) and catheter-related infection (36%), which led to 30.8% and 35.9% catheter removal, respectively. After translumbar catheter, 42.8% of the patients were successfully converted to another vascular access or peritoneal dialysis. This study data suggest that TLDC might serve as a safe, alternate access for dialysis patients in short-term who have exhausted conventional vascular access. © 2015 Wiley Periodicals, Inc.

  20. Peripherally Inserted Central Catheters and Hemodialysis Outcomes.

    PubMed

    McGill, Rita L; Ruthazer, Robin; Meyer, Klemens B; Miskulin, Dana C; Weiner, Daniel E

    2016-08-08

    Use of peripherally inserted central catheters has expanded rapidly, but the consequences for patients who eventually require hemodialysis are undefined. Our national, population-based analysis included 33,918 adult Medicare beneficiaries from the US Renal Data System who initiated hemodialysis with central venous catheters as their sole vascular access in 2010 and 2011. We used linked Medicare claims to identify peripherally inserted central catheter exposures and evaluate the associations of peripherally inserted central catheter placement with transition to working arteriovenous fistulas or grafts and patient survival using a Cox model with time-dependent variables. Among 33,918 individuals initiating hemodialysis with a catheter as sole access, 12.6% had received at least one peripherally inserted central catheter. Median follow-up was 404 days (interquartile range, 103-680 days). Among 6487 peripherally inserted central catheters placed, 3435 (53%) were placed within the 2 years before hemodialysis initiation, and 3052 (47%) were placed afterward. Multiple peripherally inserted central catheters were placed in 30% of patients exposed to peripherally inserted central catheters. Recipients of peripherally inserted central catheters were more likely to be women and have comorbid diagnoses and less likely to have received predialysis nephrology care. After adjustment for clinical and demographic factors, peripherally inserted central catheters placed before or after hemodialysis initiation were independently associated with lower likelihoods of transition to any working fistula or graft (hazard ratio for prehemodialysis peripherally inserted central catheter, 0.85; 95% confidence interval, 0.79 to 0.91; hazard ratio for posthemodialysis peripherally inserted central catheter, 0.81; 95% confidence interval, 0.73 to 0.89). Peripherally inserted central catheter placement was common and associated with adverse vascular access outcomes. Recognition of potential long

  1. Button self-retaining drainage catheter

    SciTech Connect

    Caridi, James G.; Hawkins, Irvin F.; Akins, E. William; Young, Ronald S.

    1997-07-15

    To help improve patient acceptance of long-term internal/external catheter access to the biliary tract in those with benign biliary obstruction, a simple design allows the catheter end to remain flush with the skin. It consists of a clothes button affixed to the drainage catheter with a wood screw after the catheter has been cut off at the skin exit. This button/screw device has been used successfully in 22 patients over the last 10 years; catheter exchanges were easily accomplished.

  2. Robotic positioning of standard electrophysiology catheters: a novel approach to catheter robotics.

    PubMed

    Knight, Bradley; Ayers, Gregory M; Cohen, Todd J

    2008-05-01

    Robotic systems have been developed to manipulate and position electrophysiology (EP) catheters remotely. One limitation of existing systems is their requirement for specialized catheters or sheaths. We evaluated a system (Catheter Robotics Remote Catheter Manipulation System [RCMS], Catheter Robotics, Inc., Budd Lake, New Jersey) that manipulates conventional EP catheters placed through standard introducer sheaths. The remote controller functions much like the EP catheter handle, and the system permits repeated catheter disengagement for manual manipulation without requiring removal of the catheter from the body. This study tested the hypothesis that the RCMS would be able to safely and effectively position catheters at various intracardiac sites and obtain thresholds and electrograms similar to those obtained with manual catheter manipulation. Two identical 7 Fr catheters (Blazer II; Boston Scientific Corp., Natick, Massachusetts) were inserted into the right femoral veins of 6 mongrel dogs through separate, standard 7 Fr sheaths. The first catheter was manually placed at a right ventricular endocardial site. The second catheter handle was placed in the mating holder of the RCMS and moved to approximately the same site as the first catheter using the Catheter Robotics RCMS. The pacing threshold was determined for each catheter. This sequence was performed at 2 right atrial and 2 right ventricular sites. The distance between the manually and robotically placed catheters tips was measured, and pacing thresholds and His-bundle recordings were compared. The heart was inspected at necropsy for signs of cardiac perforation or injury. Compared to manual positioning, remote catheter placement produced the same pacing threshold at 7/24 sites, a lower threshold at 11/24 sites, and a higher threshold at only 6/24 sites (p > 0.05). The average distance between catheter tips was 0.46 +/- 0.32 cm (median 0.32, range 0.13-1.16 cm). There was no difference between right atrial

  3. Ablation of hypertrophic septum using radiofrequency energy: an alternative for gradient reduction in patient with hypertrophic obstructive cardiomyopathy?

    PubMed

    Riedlbauchová, Lucie; Janoušek, Jan; Veselka, Josef

    2013-06-01

    Alcohol septal ablation and surgical myectomy represent accepted therapeutic options for treatment of symptomatic patients with hypertrophic obstructive cardiomyopathy. Long-term experience with radiofrequency ablation of arrhythmogenic substrates raised a question if this technique might be effective for left ventricular outflow tract (LVOT) gradient reduction. We report on a 63-year-old patient with recurrence of symptoms 1 year after alcohol septal ablation (ASA) leading originally to a significant reduction of both symptoms and gradient. Due to a new increase of gradient in the LVOT up to 200 mm Hg with corresponding worsening of symptoms and due to refusal of surgical myectomy by the patient, endocardial radiofrequency ablation of the septal hypertrophy (ERASH) was indicated. Radiofrequency ablation was performed in the LVOT using irrigated-tip ablation catheter; the target site was identified using intracardiac echocardiography and electroanatomical CARTO mapping. ERASH caused an immediate gradient reduction due to hypokinesis of the ablated septum. At 2-month follow-up exam, significant clinical improvement was observed, together with persistent gradient reduction assessed with Doppler echocardiography. Echocardiography and magnetic resonance revealed persistent septal hypokinesis and slight thinning of the ablated region. Septal ablation using radiofrequency energy may be a promising alternative or adjunct to the treatment of hypertrophic obstructive cardiomyopathy. Intracardiac echocardiography and electroanatomical CARTO mapping enable exact lesion placement and preservation of atrioventricular conduction.

  4. Totally implantable catheter embolism: two related cases.

    PubMed

    Ribeiro, Rodrigo Chaves; Monteiro, Aurea Cristina Ferreira; Menezes, Quirino Cavalcante; Schettini, Sérgio Tomaz; Vianna, Sonia Maria Rossi

    2008-11-01

    Long-term totally implantable catheters (e.g. Port-a-Cath) are frequently used for long-term venous access in children with cancer. The use of this type of catheter is associated with complications such as infection, extrusion, extravasation and thrombosis. Embolism of catheter fragments is a rare complication, but has potential for morbidity. The aim here was to report on two cases in which embolism of fragments of a long-term totally implantable catheter occurred. Case series study at Hospital do Servidor Público Estadual, São Paulo. Retrospective review of catheter embolism in oncological pediatric patients with long-term totally implantable catheters. The first patient was a 3-year-old girl diagnosed with stage IV Wilms' tumor. Treatment was started with the introduction of a totally implantable catheter through the subclavian vein. At the time of removal, it was realized that the catheter had fractured inside the heart. An endovascular procedure was necessary to remove the fragment. The second case was a boy diagnosed with stage II Wilms' tumor at the age of two years. At the time of removal, it was noticed that the catheter had disconnected from the reservoir and an endovascular procedure was also necessary to remove the embolized catheter. Embolism of fragments of totally implantable catheters is a rare complication that needs to be recognized even in asymptomatic patients.

  5. Radiofrequency Ablation of Metastatic Pheochromocytoma

    PubMed Central

    Venkatesan, Aradhana M.; Locklin, Julia; Lai, Edwin W.; Adams, Karen T.; Fojo, Antonio Tito; Pacak, Karel; Wood, Bradford J.

    2013-01-01

    In the present report on the preliminary safety and effectiveness of radiofrequency (RF) ablation for pheochromocytoma metastases, seven metastases were treated in six patients (mean size, 3.4 cm; range, 2.2–6 cm). α- and β-adrenergic and catecholamine synthesis inhibition and intraprocedural anesthesia monitoring were used. Safety was assessed by recording ablation-related complications. Complete ablation was defined as a lack of enhancement within the ablation zone on follow-up computed tomography. No serious adverse sequelae were observed. Complete ablation was achieved in six of seven metastases (mean follow-up, 12.3 months; range, 2.5–28 months). In conclusion, RF ablation may be safely performed for metastatic pheochromocytoma given careful attention to peri-procedural management. PMID:19875067

  6. Radiofrequency Ablation: A Nursing Perspective

    PubMed Central

    Locklin, Julia K.; Wood, Bradford J.

    2008-01-01

    Radiofrequency ablation (RFA) has emerged as a safe and predictable technology for treating certain patients with cancer who otherwise have few treatment options. Nurses need to be familiar with all phases of the RFA procedure to create an optimal environment for patients. This article offers a brief review of the RFA procedure and nurses' responsibilities in caring for these patients. Before RFA, nurses should focus on patient education and aggressive hydration. During the procedure, nurses can prevent injury by placing grounding pads appropriately, monitoring vital signs, and medicating patients as needed. After RFA, nurses should assess the skin puncture site, provide adequate pain relief, and, again, hydrate patients. Nurses who care appropriately for RFA recipients may help to improve patient outcomes and make an otherwise frightening procedure more comfortable. PMID:15973845

  7. Evaluation of left ventricular scar identification from contrast enhanced magnetic resonance imaging for guidance of ventricular catheter ablation therapy

    NASA Astrophysics Data System (ADS)

    Rettmann, M. E.; Lehmann, H. I.; Johnson, S. B.; Packer, D. L.

    2016-03-01

    Patients with ventricular arrhythmias typically exhibit myocardial scarring, which is believed to be an important anatomic substrate for reentrant circuits, thereby making these regions a key target in catheter ablation therapy. In ablation therapy, a catheter is guided into the left ventricle and radiofrequency energy is delivered into the tissue to interrupt arrhythmic electrical pathways. Low bipolar voltage regions are typically localized during the procedure through point-by-point construction of an electroanatomic map by sampling the endocardial surface with the ablation catheter and are used as a surrogate for myocardial scar. This process is time consuming, requires significant skill, and has the potential to miss low voltage sites. This has led to efforts to quantify myocardial scar preoperatively using delayed, contrast-enhanced MRI. In this paper, we evaluate the utility of left ventricular scar identification from delayed contrast enhanced magnetic resonance imaging for guidance of catheter ablation of ventricular arrhythmias. Myocardial infarcts were created in three canines followed by a delayed, contrast enhanced MRI scan and electroanatomic mapping. The left ventricle and myocardial scar is segmented from preoperative MRI images and sampled points from the procedural electroanatomical map are registered to the segmented endocardial surface. Sampled points with low bipolar voltage points visually align with the segmented scar regions. This work demonstrates the potential utility of using preoperative delayed, enhanced MRI to identify myocardial scarring for guidance of ventricular catheter ablation therapy.

  8. [Radiofrequency for the treatment of liver tumors].

    PubMed

    Elias, D; De Baere, T

    2001-04-01

    Radiofrequency is performed with thin electrodes that are placed in the center of a tumor under ultrasonographic guidance. Radiofrequency waves induce ionic agitation which destroys neighboring tissues by heat. The most recent equipment can produce necrosis of 4-cm diameter areas. Efficacy is enhanced by blocking intrahepatic blood flow which naturally refreshes the liver parenchyma. The technique has the advantage of minimal invasion and of sparing liver parenchymal tissue. radiofrequency can be performed percutaneously or by laparoscopi or laparotomy. results in most reported series have been good with low morbidity. rapid improvment of material and of new associated procedures (vascular clamping, cooling infusion of the bile ducts, transplaeurodiaphragmatic approach, combination with other new approaches in liver surgery) are continuously modifying performance levels and potential indications curently under validation. radiofrequency, like other tools for local tumor destruction, will greatly change our therapeutic strategies in the neat future.

  9. Toward guidance of epicardial cardiac radiofrequency ablation therapy using optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Fleming, Christine P.; Quan, Kara J.; Rollins, Andrew M.

    2010-07-01

    Radiofrequency ablation (RFA) is the standard of care to cure many cardiac arrhythmias. Epicardial ablation for the treatment of ventricular tachycardia has limited success rates due in part to the presence of epicardial fat, which prevents proper rf energy delivery, inadequate contact of ablation catheter with tissue, and increased likelihood of complications with energy delivery in close proximity to coronary vessels. A method to directly visualize the epicardial surface during RFA could potentially provide feedback to reduce complications and titrate rf energy dose by detecting critical structures, assessing probe contact, and confirming energy delivery by visualizing lesion formation. Currently, there is no technology available for direct visualization of the heart surface during epicardial RFA therapy. We demonstrate that optical coherence tomography (OCT) imaging has the potential to fill this unmet need. Spectral domain OCT at 1310 nm is employed to image the epicardial surface of freshly excised swine hearts using a microscope integrated bench-top scanner and a forward imaging catheter probe. OCT image features are observed that clearly distinguish untreated myocardium, ablation lesions, epicardial fat, and coronary vessels, and assess tissue contact with catheter-based imaging. These results support the potential for real-time guidance of epicardial RFA therapy using OCT imaging.

  10. [Ablation using radiofrequency in the treatment of ventricular tachycardia].

    PubMed

    Cordero Cabra, J A; Iturralde Torres, P; Lara Vaca, S; Colín Lizalde, L; Kershenovich, S; Carvajal, A; González Hermosillo, J A

    1996-01-01

    We performed radiofrequency catheter ablation in 14 consecutive patients with Ventricular Tachycardia (VT) 10 of which had healthy hearts, one patient with ischemic heart disease, one with arrhythmogenic dysplasia, one with dilated cardiomyopathy, and one with congenital heart disease. The localization of the VT was: 10 in the left posterior fascicular region, 3 in the right ventricular outflow tract (RVOT), and one patient with ischemic heart disease with the substrate in the left ventricular apex. All of them with VT refractory to pharmacological management, using an average of 2.7 drugs per patient. After all patients underwent Electrophysiological Study (EPS), an intracavitary mapping was performed, in order to locate the arrhythmogenic substrate. Later on, the RF ablation was performed, delivering an average of 15 pulses, using 40 Watts, and an average time of 25 sec. per pulse. The procedure was successful in 60% of the fascicular VT, with a 16% of recurrence; 100% of success with those originated in the RVOT with no recurrence; in the ischemic patient we achieved primary success, but with recurrence, a second session was successful with no recurrence up to date. No major complications occurred in this group. Those patients which showed no success required the use of antiarrhythmic drugs. The total success of the series is 71.4% with 10% recurrence, and no mortality.

  11. Integrated RFA/OCT catheter for real-time guidance of cardiac RFA therapy (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Fu, Xiaoyong; Blumenthal, Colin; Dosluoglu, Deniz; Wang, Yves T.; Jenkins, Michael W.; Souza, Rakesh; Snyder, Christopher; Arruda, Mauricio; Rollins, Andrew M.

    2016-03-01

    Currently, cardiac radiofrequency ablation is guided by indirect signals. We demonstrate an integrated radiofrequency ablation (RFA) and optical coherence tomography (OCT) probe for directly monitoring of the RFA procedure with OCT images in real time. The integrated RFA/OCT probe is modified from a standard commercial RFA catheter, and a newly designed and fabricated miniature forward-viewing cone-scanning OCT probe is integrated into the modified probe. The OCT system is verified with the human finger images, and the results show the integrated RFA/OCT probe can acquire high quality OCT images. The radiofrequency energy delivering function of the integrated probe is verified by comparing the RFA lesion sizes with standard commercial RFA probe. For the standard commercial probe, the average width and depth of the 10 lesions were 3.5 mm and 1.8 mm respectively. For the integrated RFA/OCT probe, the average width and depth of the 10 lesions were 3.6 mm and 1.7 mm respectively. The lesions created by the two probes are indistinguishable in size. This demonstrates that our glass window in the integrated probe has little effect on the RF energy delivery. And the integrated probe is used to monitoring the cardiac RFA procedure in real time. The results show that the RFA lesion formation can be confirmed by the loss of birefringence in the heart tissue. The system can potentially in vivo image of the cardiac wall to aid RFA therapy for cardiac arrhythmias.

  12. Outcome of radiologically placed tunneled haemodialysis catheters.

    PubMed

    Sayani, Raza; Anwar, Muhammad; Tanveer-ul-Haq; Al-Qamari, Nauman; Bilal, Muhammad Asif

    2013-12-01

    To study the outcome of radiologically placed double lumen tunneled haemodialysis catheters for the management of renal failure. Case series. Interventional Suite of Radiology Department at the Aga Khan University Hospital, Karachi, from April 2010 to June 2011. All consecutive patients who were referred to the department of radiology by the nephrologists for double lumen tunneled haemodialysis catheter (Permacath) placement during the study period were included. Patients with septicemia, those for whom follow-up was not available, those coming for catheter exchange or who died due to a noncatheter related condition were excluded. A radio-opaque, soft silicone double lumen catheter was inserted through a subcutaneous tunnel created over the anterior chest wall. The catheter tip was placed in the right atrium via the internal jugular vein. Ultrasound guidance was used for initial venous puncture. The rest of the procedure was carried out under fluoroscopic guidance. Technical success, catheter related bacteremia rates, adequacy of dialysis, patency, and adverse events were analyzed. Overall 88 tunneled haemodialysis catheters were placed in 87 patients. Patients were followed-up for duration of 1 - 307 days with mean follow-up period of 4 months. Immediate technical success was 100%. The procedural complication rate was 5.6% (5 catheters). Eight patients died during the study period, seven from causes unrelated to the procedure. One patient died due to septicemia secondary to catheter related infection. Of the remaining 69 patients, 50 (72.4%) predominantly had uneventful course during the study period. Twelve patients developed infection (17.3%); two were successfully treated conservatively while in 10 patients catheter had to be removed. Seven catheters (10.1%) failed due to mechanical problems. In 3 patients the internal jugular veins got partially thrombosed. One catheter was accidentally damaged in the ward and had to be removed. Radiological guided tunneled

  13. Untangling of knotted urethral catheters.

    PubMed

    Sambrook, Andrew J; Todd, Alistair

    2007-04-01

    Intravesical catheter knotting during micturating cystourethrography is a rare but recognized complication of the procedure. We were able to untangle a knot utilizing a fluoroscopically guided vascular guidewire. Following this success, a small study was performed using a model. Various types of guidewires and techniques were tested for different diameters of knots in order to predict the likelihood of success in this type of situation.

  14. Hospital-wide survey of the adequacy in the number of vascular catheters and catheter lumens.

    PubMed

    Fernández-Ruiz, Mario; Carretero, Alberto; Díaz, David; Fuentes, Cristina; González, José Ignacio; García-Reyne, Ana; Aguado, José María; López-Medrano, Francisco

    2014-01-01

    Removal of unnecessary catheters has been proposed as an important measure to reduce catheter-related morbidity. Nevertheless, there is scarce information about the potential magnitude of such intervention. The present study was aimed at analyzing the appropriateness of use of vascular catheters and catheter lumens in the inpatient setting. Cross-sectional survey. The entire population of adult inpatients admitted to a 1368-bed tertiary-care hospital in a single day. We used a set of preestablished criteria to evaluate the appropriateness of use of vascular catheters and catheter lumens according to the number and administration regimen of intravenous drugs. Out of 834 patients, 575 (68.9%) had ≥1 vascular catheters in place on the day of the survey. The type and distribution of the 703 surveyed catheters were peripheral venous catheter, 80.6%; central venous catheter, 15.8%; and arterial catheter, 3.6%. We found an overall mean of 2.06 ± 0.82 lumens per catheter, with significant differences between intensive care units and conventional wards (P < 0.0001). Based on our criteria, 126 out of 575 patients (21.9%) had an inappropriate number of catheters (medical wards, 20.0%; surgical wards, 23.9%; intensive care units, 26.3%), and 631 out of 14248 nonarterial catheter lumens (43.6%) were considered unnecessary. Significant room exists for improving the adequacy of the number of vascular catheters and catheter lumens as a potentially useful tool for decreasing the incidence of catheter-related bloodstream infection. © 2013 Society of Hospital Medicine.

  15. Initial human feasibility of infusion needle catheter ablation for refractory ventricular tachycardia.

    PubMed

    Sapp, John L; Beeckler, Christopher; Pike, Robert; Parkash, Ratika; Gray, Christopher J; Zeppenfeld, Katja; Kuriachan, Vikas; Stevenson, William G

    2013-11-19

    Ablation of ventricular tachycardia (VT) is sometimes unsuccessful when ablation lesions are of insufficient depth to reach arrhythmogenic substrate. We report the initial experience with the use of a catheter with an extendable/retractable irrigated needle at the tip capable of intramyocardial mapping and ablation. Sequential consenting patients with recurrent VT underwent ablation with the use of a needle-tipped catheter. At target sites, the needle was advanced 7 to 9 mm into the myocardium, permitting pacing and recording. Infusion of saline/iodinated contrast mixture excluded perforation and ensured intramyocardial deployment. Further infusion was delivered before and during temperature-controlled radiofrequency energy delivery through the needle. All 8 patients included (6 male; mean age, 54) with a mean left ventricular ejection fraction of 29% were refractory to multiple antiarrhythmic drugs, and 1 to 4 previous catheter ablation attempts (epicardial in 4) had failed. Patients had 1 to 7 (median, 2) VTs present or inducible; 2 were incessant. Some intramyocardial VT mapping was possible in 7 patients. A mean of 22 (limits, 3-48) needle ablation lesions were applied in 8 patients. All patients had at least 1 VT terminated or rendered noninducible. During a median of 12 months follow-up, 4 patients were free of recurrent VT, and 3 patients were improved, but had new VTs occur at some point during follow-up. Two died of the progression of preexisting heart failure without recurrent VT. Complications included tamponade in 1 patient and heart block in 2 patients. Intramyocardial infusion-needle catheter ablation is feasible and permits control of some VTs that have been refractory to conventional catheter ablation therapy, warranting further study.

  16. Orthogonal electrode catheter array for mapping of endocardial focal site of ventricular activation

    SciTech Connect

    Desai, J.M.; Nyo, H.; Vera, Z.; Seibert, J.A.; Vogelsang, P.J. )

    1991-04-01

    Precise location of the endocardial site of origin of ventricular tachycardia may facilitate surgical and catheter ablation of this arrhythmia. The endocardial catheter mapping technique can locate the site of ventricular tachycardia within 4-8 cm2 of the earliest site recorded by the catheter. This report describes an orthogonal electrode catheter array (OECA) for mapping and radiofrequency ablation (RFA) of endocardial focal site of origin of a plunge electrode paced model of ventricular activation in dogs. The OECA is an 8 F five pole catheter with four peripheral electrodes and one central electrode (total surface area 0.8 cm{sup 2}). In eight mongrel dogs, mapping was performed by arbitrarily dividing the left ventricle (LV) into four segments. Each segment was mapped with OECA to find the earliest segment. Bipolar and unipolar electrograms were obtained. The plunge electrode (not visible on fluoroscopy) site was identified by the earliest wave front arrival times of -30 msec or earlier at two or more electrodes (unipolar electrograms) with reference to the earliest recorded surface ECG (I, AVF, and V1). Validation of the proximity of the five electrodes of the OECA to the plunge electrode was performed by digital radiography and RFA. Pathological examination was performed to document the proximity of the OECA to the plunge electrode and also for the width, depth, and microscopic changes of the ablation. To find the segment with the earliest LV activation a total of 10 {plus minus} 3 (mean {plus minus} SD) positions were mapped. Mean arrival times at the two earlier electrodes were -39 {plus minus} 4 msec and -35 {plus minus} 3 msec. Digital radiography showed the plunge electrode to be within the area covered by all five electrodes in all eight dogs. The plunge electrode was within 1 cm2 area of the region of RFA in all eight dogs.

  17. 3D model-based catheter tracking for motion compensation in EP procedures

    NASA Astrophysics Data System (ADS)

    Brost, Alexander; Liao, Rui; Hornegger, Joachim; Strobel, Norbert

    2010-02-01

    Atrial fibrillation is the most common sustained heart arrhythmia and a leading cause of stroke. Its treatment by radio-frequency catheter ablation, performed using fluoroscopic image guidance, is gaining increasingly more importance. Two-dimensional fluoroscopic navigation can take advantage of overlay images derived from pre-operative 3-D data to add anatomical details otherwise not visible under X-ray. Unfortunately, respiratory motion may impair the utility of these static overlay images for catheter navigation. We developed an approach for image-based 3-D motion compensation as a solution to this problem. A bi-plane C-arm system is used to take X-ray images of a special circumferential mapping catheter from two directions. In the first step of the method, a 3-D model of the device is reconstructed. Three-dimensional respiratory motion at the site of ablation is then estimated by tracking the reconstructed catheter model in 3-D. This step involves bi-plane fluoroscopy and 2-D/3-D registration. Phantom data and clinical data were used to assess our model-based catheter tracking method. Experiments involving a moving heart phantom yielded an average 2-D tracking error of 1.4 mm and an average 3-D tracking error of 1.1 mm. Our evaluation of clinical data sets comprised 469 bi-plane fluoroscopy frames (938 monoplane fluoroscopy frames). We observed an average 2-D tracking error of 1.0 mm +/- 0.4 mm and an average 3-D tracking error of 0.8 mm +/- 0.5 mm. These results demonstrate that model-based motion-compensation based on 2-D/3-D registration is both feasible and accurate.

  18. The stuck catheter: a hazardous twist to the meaning of permanent catheters.

    PubMed

    Vellanki, Venkat Sainaresh; Watson, Diane; Rajan, Dheeraj K; Bhola, Cynthia B; Lok, Charmaine E

    2015-01-01

    Permanent central venous catheter use is associated with significant complications that often require their timely removal. An uncommon complication is resistant removal of the catheter due to adherence of the catheter to the vessel wall. This occasionally mandates invasive interventions for removal. The aim of this study is to describe the occurrence of this "stuck catheter" phenomenon and its consequences. A retrospective review of all the removed tunneled hemodialysis catheters from July 2005 to December 2014 at a single academic-based hemodialysis center to determine the incidence of stuck catheters. Data were retrieved from a prospectively maintained computerized vascular access database and verified manually against patient charts. In our retrospective review of tunneled hemodialysis catheters spanning close to a decade, we found that 19 (0.92%) of catheters were retained, requiring endovascular intervention or open sternotomy. Of these, three could not be removed, with one patient succumbing to catheter-related infection. Longer catheter vintage appeared to be associated with 'stuck catheter'. Retention of tunneled central venous catheters is a rare but important complication of prolonged tunneled catheter use that nephrologists should be aware of. Endoluminal balloon dilatation procedures are the initial approach, but surgical intervention may be necessary.

  19. Catheter-tract infections in rhesus macaques (Macaca mulatta) with indwelling intravenous catheters.

    PubMed

    Taylor, W M; Grady, A W

    1998-10-01

    Development of catheter-tract infections in experimental animals can have devastating consequences on animal health and the functional lifespan of surgical implants. To measure the incidence of catheter-tract infections in animals with exteriorized intravenous catheters in this facility and assess the effects of these infections on mean catheter lifespan, health records of 31 Macaca mulatta with catheters were reviewed. Records spanned the interval of January 1, 1996 through October 1, 1997. Catheter-tract infections in 16 of 53 (30.2%) monkeys with catheters were diagnosed based on a combination of clinical signs of infection and results of bacterial culture. Segmental catheter-tract infections reduced mean catheter lifespan to 147 days, compared with 354 days for uninfected catheters. Exit-wound, local tunnel, and surgical-site infections did not significantly reduce catheter lifespan. Bacterial culture reports documented 31 isolates; 41.9% (13 of 31) were coagulase-negative staphylococci, and 22.6% (7 of 31) were Staphylococcus aureus. Of 20 isolates tested, 15 (75%) were resistant to methicillin/oxacillin in vitro. Antimicrobial susceptibility testing of methicillin-resistant and methicillin-susceptible isolates indicated that, compared with methicillin-sensitive isolates, methicillin-resistant isolates had a pattern of multiple antibiotic resistance. Catheter-tract infections were common in this colony of rhesus macaques, and clinically severe infections caused a drastic reduction in catheter lifespan. Approximately half (48%) the bacterial isolates were methicillin-resistant gram-positive bacteria.

  20. Optimization of dialysis catheter function.

    PubMed

    Gallieni, Maurizio; Giordano, Antonino; Rossi, Umberto; Cariati, Maurizio

    2016-03-01

    Central venous catheters (CVCs) are essential in the management of hemodialysis patients, but they also carry unintended negative consequences and in particular thrombosis and infection, adversely affecting patient morbidity and mortality. This review will focus on the etiology, prevention, and management of CVC-related dysfunction, which is mainly associated with inadequate blood flow. CVC dysfunction is a major cause of inadequate depuration. Thrombus, intraluminal and extrinsic, as well as fibrous connective tissue sheath (traditionally indicated as fibrin sheath) formation play a central role in establishing CVC dysfunction. Thrombolysis with urokinase or recombinant tissue plasminogen activator (rTPA) can be undertaken in the dialysis unit, restoring adequate blood flow in most patients, preserving the existing catheter, and avoiding an interventional procedure. If thrombolytics fail, mainly because of the presence of fibrous connective tissue sheath, catheter exchange with fibrin sheath disruption may be successful and preserve the venous access site. Prevention of CVC dysfunction is important for containing costly pharmacologic and interventional treatments, which also affect patients' quality of life. Prevention is based on the use of anticoagulant and/or thrombolytic CVC locks, which are only partially effective. Chronic oral anticoagulation with warfarin has also been proposed, but its use for this indication is controversial and its overall risk-benefit profile has not been clearly established.

  1. Central vascular catheters and infections.

    PubMed

    Dioni, Elisabetta; Franceschini, Renata; Marzollo, Roberto; Oprandi, Daniela; Chirico, Gaetano

    2014-03-01

    Newborn infants in critical conditions require a permanent intra-venous line to allow for the administration of fluids, parenteral nutrition and drugs. The use of central venous catheters, however, is associated with an increased risk of infections, leading to prolongation of length of stay and higher hospitalization costs, particularly in extremely preterm infants. Dwell time is a significant factor for complications, with a predicted risk of catheter related infections of about 4 per 1000 catheter-days. To reduce the incidence of complications, several requirements must be met, including adequate staff and resources to provide education, training, and quality improvement programs, within a culture of communication and teamwork. Rigorous reporting schedule on line care and the implementation of unique bundle elements, the use of health care failure mode and effect analysis, the judicious use of antibiotics through an antimicrobial stewardship strategy, the application of specific antifungal prophylaxis are among the most effective interventions, while the addition of heparin to parenteral solution, or the use of antibiotic plus heparin lock therapy are under evaluation. Nursing assistance plays a fundamental role in managing central venous lines and in reducing or preventing the incidence of infection, by the application of several complex professional strategies.

  2. Catheter-associated urinary tract infections.

    PubMed

    Warren, J W

    2001-04-01

    Nosocomial urinary tract infection (UTI) is the most common infection acquired in both hospitals and nursing homes and is usually associated with catheterization. This infection would be even more common but for the use of the closed catheter system. Most modifications have not improved on the closed catheter itself. Even with meticulous care, this system will not prevent bacteriuria. After bacteriuria develops, the ability to limit its complications is minimal. Once a catheter is put in place, the clinician must keep two concepts in mind: keep the catheter system closed in order to postpone the onset of bacteriuria, and remove the catheter as soon as possible. If the catheter can be removed before bacteriuria develops, postponement becomes prevention.

  3. Infections associated with the central venous catheters.

    PubMed

    Drasković, Biljana; Fabri, Izabella; Benka, Anna Uram; Rakić, Goran

    2014-01-01

    Central venous catheters are of an essential importance to critically ill patients who require long-term venous access for various purposes. Their use made the treatment much easier, but still they are not harmless and are prone to numerous complications. Catheter infections represent the most significant complication in their use. The frequency of infections varies in different patient care settings, but their appearance mostly depends on the patient's health condition, catheter insertion time, localization of the catheter and type of the used catheter. Since they are one of the leading causes of nosocomial infections and related to significant number of morbidity and mortality in intensive care units, it is very important that maximal aseptic precautions are taken during the insertion and the maintenance period. Prevention of infection of the central venous catheters demands several measures that should be applied routinely.

  4. Position Control of Motion Compensation Cardiac Catheters

    PubMed Central

    Kesner, Samuel B.; Howe, Robert D.

    2011-01-01

    Robotic catheters have the potential to revolutionize cardiac surgery by enabling minimally invasive structural repairs within the beating heart. This paper presents an actuated catheter system that compensates for the fast motion of cardiac tissue using 3D ultrasound image guidance. We describe the design and operation of the mechanical drive system and catheter module and analyze the catheter performance limitations of friction and backlash in detail. To mitigate these limitations, we propose and evaluate mechanical and control system compensation methods, including inverse and model-based backlash compensation, to improve the system performance. Finally, in vivo results are presented that demonstrate that the catheter can track the cardiac tissue motion with less than 1 mm RMS error. The ultimate goal of this research is to create a fast and dexterous robotic catheter system that can perform surgery on the delicate structures inside of the beating heart. PMID:21874124

  5. Translumbar placement of paired hemodialysis catheters (Tesio Catheters) and follow-up in 10 patients

    SciTech Connect

    Biswal, Rajiv; Nosher, John L.; Siegel, Randall L.; Bodner, Leonard J.

    2000-01-15

    For lack of other suitable access, 10 consecutive patients received paired hemodialysis catheters for long-term hemodialysis using a translumbar approach to the inferior vena cava (IVC). All attempts were successful. Five paired catheters were placed using the single-puncture technique, and five using the dual-puncture technique. Catheters were in place for a total of 2252 catheter days. The average duration of catheter placement was 250 days (range 30-580 days). All catheters were functioning up to the time the study was completed or the patient died. The most common complication was partial dislodgment of the catheter in 3 of 23 catheters (13%), all occurring in obese patients. One episode of retroperitoneal hemorrhage was noted in a patient having the single-access technique. There were no episodes of infection or IVC thrombosis.

  6. Accidental Entrapment of Electrical Mapping Catheter by Chiari's Network in Right Atrium during Catheter Ablation Procedure

    PubMed Central

    Sakamoto, Atsushi; Urushida, Tsuyoshi; Sakakibara, Tomoaki; Sano, Makoto; Suwa, Kenichiro; Saitoh, Takeji; Saotome, Masao; Katoh, Hideki; Satoh, Hiroshi; Hayashi, Hideharu

    2016-01-01

    A 78-year-old male was admitted to our hospital due to frequent palpitation. His electrocardiogram (ECG) presented regular narrow QRS tachycardia with 170 bpm, and catheter ablation was planned. During electroanatomical mapping of the right atrium (RA) with a multiloop mapping catheter, the catheter head was entrapped nearby the ostium of inferior vena cava. Rotation and traction of the catheter failed to detach the catheter head from the RA wall. Exfoliation of connective tissue twined around catheter tip by forceps, which were designed for endomyocardial biopsy, succeeded to retract and remove the catheter. Postprocedural echocardiography and pathologic examination proved the existence of Chiari's network. The handling of complex catheters in the RA has a potential risk of entrapment with Chiari's network. PMID:27366332

  7. Electrophysiological mapping and radiofrequency catheter ablation for ventricular tachycardia in a patient with peripartum cardiomyopathy.

    PubMed

    Tokuda, Michifumi; Stevenson, William G; Nagashima, Koichi; Rubin, David A

    2013-11-01

    A 38-year-old female with prior failed endocardial ablation for ventricular tachycardia (VT) was referred for further treatment. She had been diagnosed with peripartum cardiomyopathy 7 years before and had persistent left ventricular dysfunction with an ejection fraction of 20%. Epicardial voltage mapping showed extensive epicardial scar despite absence of endocardial scar. Five distinct VT morphologies were induced. Ablation was aided by electrogram characteristics, pace mapping, entrainment mapping, and establishing electrical inexcitability along areas of epicardial scar. After epicardial ablation no sustained VT was induced. She had been doing well without VT occurrence but died 1 year later unexpectedly at home.

  8. Thrombolytic therapy for central venous catheter occlusion

    PubMed Central

    Baskin, Jacquelyn L.; Reiss, Ulrike; Wilimas, Judith A.; Metzger, Monika L.; Ribeiro, Raul C.; Pui, Ching-Hon; Howard, Scott C.

    2012-01-01

    Background Long-term central venous catheters have improved the quality of care for patients with chronic illnesses, but are complicated by obstructions which can result in delay of treatment or catheter removal. Design and Methods This paper reviews thrombolytic treatment for catheter obstruction. Literature from Medline searches using the terms “central venous catheter”, “central venous access device” OR “central venous line” associated with the terms “obstruction”, “occlusion” OR “thrombolytic” was reviewed. Efficacy of thrombolytic therapy, central venous catheter clearance rates and time to clearance were assessed. Results Alteplase, one of the current therapies, clears 52% of obstructed catheters within 30 min with 86% overall clearance (after 2 doses, when necessary). However, newer medications may have higher efficacy or shorter time to clearance. Reteplase cleared 67–74% within 30–40 min and 95% of catheters overall. Occlusions were resolved in 70 and 83% of patients with one and 2 doses of tenecteplase, respectively. Recombinant urokinase cleared 60% of catheters at 30 min and 73% overall. Alfimeprase demonstrated rapid catheter clearance with resolution in 40% of subjects within 5 min, 60% within 30 min, and 80% within 2 h. Additionally, urokinase prophylaxis decreased the incidence of catheter occlusions from 16–68% in the control group to 4–23% in the treatment group; in some studies, rates of catheter infections were also decreased in the urokinase group. Conclusions Thrombolytic agents successfully clear central venous catheter occlusions in most cases. Newer agents may act more rapidly and effectively than currently utilized therapies, but randomized studies with direct comparisons of these agents are needed to determine optimal management for catheter obstruction. PMID:22180420

  9. Candida utilis catheter-related bloodstream infection

    PubMed Central

    Scoppettuolo, Giancarlo; Donato, Concetta; De Carolis, Elena; Vella, Antonietta; Vaccaro, Luisa; La Greca, Antonio; Fantoni, Massimo

    2014-01-01

    Central venous catheter-related fungemia are increasing in the last years, also due to rare fungi. We report the case of a Candida utilis catheter-related bloodstream infection in a patient with metastatic carcinoma of the bladder and a long term totally implanted venous catheter. The diagnosis was done by paired blood cultures and differential time to positivity. The Candida species was rapidly identified by MALDI-TOF mass spectrometry. The patient was successfully treated with anidulafungine. PMID:25473600

  10. Polyurethane II catheter as long-indwelling intravenous catheter in patients with cancer.

    PubMed

    Volkow, Patricia; Vázquez, Carolina; Téllez, Odilia; Aguilar, Catalina; Barrera, Laura; Rodrgíuez, Eneida; Vilar-Compte, Diana; Zinser, Juan; Calderón, Ernesto; Pérez-Padilla, José Rogelio; Mohar, Alejandro

    2003-11-01

    Silicone has been the standard material for indwelling devices to date. Polyurethane II exhibits properties that makes it suitable as a component of long-indwelling vascular access, with the added advantage of low cost. To describe the experience of an intravenous therapy team with 206 polyurethane II catheters used as long-indwelling vascular access in patients with cancer. All polyurethane II single- and double-lumen catheters implanted between January 1, 1994, and March 15, 1995, were analyzed, including time of stay and type and rate of infectious and noninfectious complications. A total of 206 catheters were placed--164 single-lumen and 42 double-lumen catheters--in 190 patients; average stay was 101 days (range, 1-445 days). The infection incidence rate was 0.66 per 1000 catheter-days for single-lumen catheters and 1.6 per 1000 catheter-days for double-lumen catheters. Noninfectious complications included 1 thrombosis (incidence rate, 0.06 per 1000 catheter-days for single-lumen and none for double-lumen catheters), 5 catheter ruptures (2.4%), and 1 pneumothorax (0.48%). Twelve catheters (8.3%) were removed because of complications; only 1 was infectious. The remaining 17 infectious episodes (94.4%) were resolved without catheter removal. Our complication rate with single-lumen catheters in this series was similar to our previous experience with a nontunneled silicone catheter. Our findings indicate that polyurethane II catheters have proven useful and safe as long-indwelling vascular access in patients with cancer at our hospital at a considerably lower cost.

  11. Acute hemodynamic decompensation during catheter ablation of scar-related ventricular tachycardia: incidence, predictors, and impact on mortality.

    PubMed

    Santangeli, Pasquale; Muser, Daniele; Zado, Erica S; Magnani, Silvia; Khetpal, Sumun; Hutchinson, Mathew D; Supple, Gregory; Frankel, David S; Garcia, Fermin C; Bala, Rupa; Riley, Michael P; Lin, David; Rame, J Eduardo; Schaller, Robert; Dixit, Sanjay; Marchlinski, Francis E; Callans, David J

    2015-02-01

    The occurrence of periprocedural acute hemodynamic decompensation (AHD) in patients undergoing radiofrequency catheter ablation of scar-related ventricular tachycardia (VT) has not been previously investigated. We identified univariate predictors of periprocedural AHD in 193 consecutive patients undergoing radiofrequency catheter ablation of scar-related VT. AHD was defined as persistent hypotension despite vasopressors and requiring mechanical support or procedure discontinuation. AHD occurred in 22 (11%) patients. Compared with the rest of the population, patients with AHD were older (68.5±10.7 versus 61.6±15.0 years; P=0.037); had a higher prevalence of diabetes mellitus (36% versus 18%; P=0.045), ischemic cardiomyopathy (86% versus 52%; P=0.002), chronic obstructive pulmonary disease (41% versus 13%; P=0.001), and VT storm (77% versus 43%; P=0.002); had more severe heart failure (New York Heart Association class III/IV: 55% versus 15%, P<0.001; left ventricular ejection fraction: 26±10% versus 36±16%, P=0.003); and more often received periprocedural general anesthesia (59% versus 29%; P=0.004). At 21±7 months follow-up, the mortality rate was higher in the AHD group compared with the rest of the population (50% versus 11%, log-rank P<0.001). AHD occurs in 11% of patients undergoing radiofrequency catheter ablation of scar-related VT and is associated with increased risk of mortality over follow-up. AHD may be predicted by clinical factors, including advanced age, ischemic cardiomyopathy, more severe heart failure status (New York Heart Association class III/IV, lower ejection fraction), associated comorbidities (diabetes mellitus and chronic obstructive pulmonary disease), presentation with VT storm, and use of general anesthesia. © 2014 American Heart Association, Inc.

  12. Catheter ablation - new developments in robotics.

    PubMed

    Chun, K R Julian; Schmidt, Boris; Köktürk, Bülent; Tilz, Roland; Fürnkranz, Alexander; Konstantinidou, Melanie; Wissner, Erik; Metzner, Andreas; Ouyang, Feifan; Kuck, Karl-Heinz

    2008-12-01

    Catheter ablation has become the curative treatment modality for various arrhythmias. Extending the indications for catheter ablation from simple supraventricular tachycardias to complex arrhythmias such as ventricular tachycardia or atrial fibrillation, the investigator faces prolonged procedure times, fluoroscopy exposure and the need for stable and reproducible catheter movement. Recently, remote-controlled robotic catheter ablation has emerged as a novel ablation concept to meet these requirements. This review describes the two available robotic ablation systems and summarizes their clinical applications and current human experience.

  13. Erroneous laboratory values obtained from central catheters.

    PubMed

    Johnston, J B; Messina, M

    1991-01-01

    Serious analytic errors in potassium measurements have been identified in blood specimens obtained from newly inserted central catheters. Erroneous elevated readings have been related to interactions of chemistry analyzer electrodes and substances fixed to external and intraluminal walls of the central catheter. Anecdotal summaries of this phenomenon are presented to enable the nurse to recognize potential problems when sampling blood from central catheters. Studies were performed to determine the amount of flush necessary to clear the catheter of interfering residue. To eliminate this potentially hazardous occurrence, recommended flush volumes, nursing implications, and actions are described.

  14. [The microbiologist and the catheter related infection].

    PubMed

    García-Rodríguez, J; de Pablos, M; Gutiérrez, A

    2010-06-01

    Different multicentre epidemiological studies such as ENVIN-HELICS or EPINE, have remarked that catheter related bloodstream infection (CRBI) is an increasingly condition in hospital environment. The microbiologist plays a major role in the diagnosis, either by recommending what type of catheter must be considered for confirmatory diagnosis, when these samples must be sent for culture, when is indicated to perform surveillance studies of the catheter and what results are clinically significant to be informed. In this paper, different aspects of the CRBI, such as the pathogenesis, etiology, epidemiology and diagnosis are reviewed. The different microbiological diagnostic methods, both conservatives and those involving the removal of the catheter are up-to-dated.

  15. Radiofrequency Ablation Beyond the Liver

    PubMed Central

    Neeman, Ziv; Wood, Bradford J.

    2008-01-01

    Radiofrequency ablation (RFA) has begun to show promise for extrahepatic indications. Although much of the reported work on image-guided RFA of liver neoplasms is quite promising, it is even earlier in the evaluation and validation process for extrahepatic RFA, with few short-term and no long-term studies reported. Although there are much more data for liver RFA with almost 3,000 cases reported in the literature, there are a number of ongoing investigations of RFA for tumors in the kidney, lung, bone, breast, bone, and adrenal gland. Debulking and pain control with RFA present palliative options becoming increasingly popular weapons in the interventionalist's oncology arsenal. Metastatic disease with a wide variety of primary histologies in a myriad of locations may be treated with RFA after a careful consideration of the risk-to-benefit ratio balance. The RFA technique can be slightly different outside the liver. Specifically, differing dielectric tissue characteristics may markedly alter the RFA treatment. Each different RFA system has a unique risk and advantage profile. Extrahepatic indications and contraindications will be suggested. Treatment tips and the unique complications and considerations will be introduced for some of the more common extrahepatic locations. PMID:12524646

  16. Radiofrequency-assisted liver resection.

    PubMed

    Delis, Spiros G; Bakoyiannis, Andreas; Tassopoulos, Nikos; Athanasiou, Kostas; Madariaga, Juan; Dervenis, Christos

    2008-08-01

    Surgical resection remains the treatment of choice for primary, secondary liver cancer and a number of benign liver lesions. Complications are mainly related to blood loss. Radiofrequency-assisted liver resection (RF-LR) has been proposed in order to achieve minimal blood loss during parenchymal transection. Between May 2005 and April 2007, 46 consecutive patients with various hepatic lesions underwent RF-LR using Radionics, Cool-Tip System. There were 28 men and 18 women with median age 65 years (range 54-76 years). Twelve major and 34 minor hepatectomies were performed for various diseases: hepatocellular carcinoma (n=19), metastatic carcinoma (n=23), focal nodal hyperplasia (n=2) and intrahepatic cholangiocarcinoma (ICC) (n=2). Hepatic inflow occlusion was not used. No perioperative death was documented. Median blood loss was 100ml (range 30-300cm(3)). Blood transfusion was required postoperatively in one patient. Median transection time was 35min (15-60min). Three patients developed biliary fistulas, four patients pleural effusions, one patient hyperbilirubinemia, two pneumonia and four wound infection. The median postoperative hospital stay was 6 days (range 4-10 days). In a median 12 month follow-up (range 3-24 months), four patients with colorectal metastases (CRM) and one patient with ICC developed recurrence. Cool-Tip RF device provides a unique, simple and safe method of bloodless liver resections and is indicated in cirrhotic patients with challenging hepatectomies (segment VIII, central resections).

  17. The radiofrequency magnetic dipole discharge

    NASA Astrophysics Data System (ADS)

    Martines, E.; Zuin, M.; Marcante, M.; Cavazzana, R.; Fassina, A.; Spolaore, M.

    2016-05-01

    This paper describes a novel and simple concept of plasma source, which is able to produce a radiofrequency magnetized discharge with minimal power requirements. The source is based on the magnetron concept and uses a permanent magnet as an active electrode. The dipolar field produced by the magnet confines the electrons, which cause further ionization, thus producing a toroidally shaped plasma in the equatorial region around the electrode. A plasma can be ignited with such scheme with power levels as low as 5 W. Paschen curves have been built for four different working gases, showing that in Helium or Neon, plasma breakdown is easily obtained also at atmospheric pressure. The plasma properties have been measured using a balanced Langmuir probe, showing that the electron temperature is around 3-4 eV and higher in the cathode proximity. Plasma densities of the order of 1016 m-3 have been obtained, with a good positive scaling with applied power. Overall, the electron pressure appears to be strongly correlated with the magnetic field magnitude in the measurement point.

  18. The radiofrequency magnetic dipole discharge

    SciTech Connect

    Martines, E. Zuin, M.; Cavazzana, R.; Fassina, A.; Spolaore, M.; Marcante, M.

    2016-05-15

    This paper describes a novel and simple concept of plasma source, which is able to produce a radiofrequency magnetized discharge with minimal power requirements. The source is based on the magnetron concept and uses a permanent magnet as an active electrode. The dipolar field produced by the magnet confines the electrons, which cause further ionization, thus producing a toroidally shaped plasma in the equatorial region around the electrode. A plasma can be ignited with such scheme with power levels as low as 5 W. Paschen curves have been built for four different working gases, showing that in Helium or Neon, plasma breakdown is easily obtained also at atmospheric pressure. The plasma properties have been measured using a balanced Langmuir probe, showing that the electron temperature is around 3–4 eV and higher in the cathode proximity. Plasma densities of the order of 10{sup 16 }m{sup −3} have been obtained, with a good positive scaling with applied power. Overall, the electron pressure appears to be strongly correlated with the magnetic field magnitude in the measurement point.

  19. Housestaff Knowledge Related to Urinary Catheter Utilization and Catheter-Associated Urinary Tract Infections (CAUTIs)

    PubMed Central

    Paras, Molly L.; Shenoy, Erica S.; Hsu, Heather E.; Walensky, Rochelle P.; Hooper, David C.

    2015-01-01

    Despite published catheter-associated urinary tract infection (CAUTI) prevention guidelines, inappropriate catheter use is common. We surveyed housestaff about their knowledge of CAUTIs at a teaching hospital and found the majority is aware of prevention guidelines; however, their application to clinical scenarios and catheter practices fall short of national goals. PMID:26278269

  20. Catheter indwell time and phlebitis development during peripheral intravenous catheter administration

    PubMed Central

    Pasalioglu, Kadriye Burcu; Kaya, Hatice

    2014-01-01

    Objective: Intravenous catheters have been indispensable tools of modern medicine. Although intravenous applications can be used for a multitude of purposes, these applications may cause complications, some of which have serious effects. Of these complications, the most commonly observed is phlebitis. This study was conducted to determine the effect of catheter indwell time on phlebitis development during peripheral intravenous catheter administration. Methods: This study determined the effect of catheter indwell time on phlebitis development during peripheral intravenous catheter administration. The study included a total of 103 individuals who were administered 439 catheters and satisfied the study enrollment criteria at one infectious diseases clinic in Istanbul/Turkey. Data were compiled from Patient Information Forms, Peripheral Intravenous Catheter and Therapy Information Forms, reported grades based on the Visual Infusion Phlebitis Assessment Scale, and Peripheral Intravenous Catheter Nurse Observation Forms. The data were analyzed using SPSS. Results : The mean patient age was 53.75±15.54 (standard deviation) years, and 59.2% of the study participants were men. Phlebitis was detected in 41.2% of peripheral intravenous catheters, and the rate decreased with increased catheter indwell time. Analyses showed that catheter indwell time, antibiotic usage, sex, and catheterization sites were significantly associated with development of phlebitis. Conclusion: The results of this study show that catheters can be used for longer periods of time when administered under optimal conditions and with appropriate surveillance. PMID:25097505

  1. 21 CFR 882.4725 - Radiofrequency lesion probe.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .... (a) Identification. A radiofrequency lesion probe is a device connected to a radiofrequency (RF) lesion generator to deliver the RF energy to the site within the nervous system where a lesion is...

  2. 21 CFR 882.4725 - Radiofrequency lesion probe.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    .... (a) Identification. A radiofrequency lesion probe is a device connected to a radiofrequency (RF) lesion generator to deliver the RF energy to the site within the nervous system where a lesion is...

  3. 21 CFR 882.4725 - Radiofrequency lesion probe.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    .... (a) Identification. A radiofrequency lesion probe is a device connected to a radiofrequency (RF) lesion generator to deliver the RF energy to the site within the nervous system where a lesion is...

  4. 21 CFR 882.4725 - Radiofrequency lesion probe.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .... (a) Identification. A radiofrequency lesion probe is a device connected to a radiofrequency (RF) lesion generator to deliver the RF energy to the site within the nervous system where a lesion is...

  5. 21 CFR 882.4725 - Radiofrequency lesion probe.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    .... (a) Identification. A radiofrequency lesion probe is a device connected to a radiofrequency (RF) lesion generator to deliver the RF energy to the site within the nervous system where a lesion is...

  6. A novel hybrid transcatheter ablation system that combines radiofrequency and cryoenergy.

    PubMed

    Khairy, Paul; Cartier, Catherine; Chauvet, Patrick; Tanguay, Jean-François; Siméon, Bertin; Lalonde, Jean-Pierre; Dubuc, Marc

    2008-02-01

    Radiofrequency (RF) and cryoenergy are largely considered independent modalities for the transcatheter ablation of cardiac arrhythmias. There are numerous theoretical advantages to engineering a system capable of delivering both energy forms. We designed a hybrid steerable catheter capable of delivering RF and cryoenergy independently, sequentially, and simultaneously. The novel catheter system was tested pre-clinically by creating a total of 180 ablation lesions in 20 mongrel dogs. Right atrial and right and left ventricular sites were preselected by a randomized factorial design devised to compare sequential and simultaneous RF and cryoenergy applications to standard RF, irrigated RF, and standard cryoablation. A steerable 4-mm electrode-tip hybrid catheter ("Fire and Ice") was created by modifying a 7 F cryocatheter (Freezor, CryoCath Technologies, Montreal, Canada). RF energy was injected via a copper wire, thermocouples were isolated to reduce RF interference, and 100 KHz band pass filters and RF chokes were added. Sequential low-dose RF (20 W, 60 seconds) preceding or following cryoablation resulted in larger lesions (P = 0.0010). The addition of RF energy did, however, produce more thrombus than cryoenergy alone, with clot detected on 82.4% versus 12.1% of ablation lesions, P < 0.0001. Simultaneously applying the two energy modalities (45 W, 10 or 30 degrees C, 60 seconds) created more voluminous lesions than standard RF ablation (median 288.1 vs 126.1 mm(3), P = 0.0333) of similar dimension to irrigated RF ablation. A versatile catheter system was fashioned capable of creating standard cryoablation lesions, standard RF lesions, and simultaneous lesions of similar dimension to irrigated RF.

  7. Comparison of heat induced damage at the saphenofemoral junction after ablation with 1,470 nm laser or radiofrequency.

    PubMed

    Ozcinar, Evren; Cakici, Mehmet; Korun, Oktay; Han, Unsal; Kiziltepe, Ugursay

    2017-03-01

    The aim of this study was to evaluate the heat induced damage at the saphenofemoral junction level according to histopathological changes after radiofrequency or 1,470 nm radial tip laser ablation. Varicose vein segments of 6-10 mm in diameter were exposed to radiofrequency (Closure Fast catheter, 7 cm heat segment, one cycle, 15 seconds, 10 Watt, 120 °C) or laser ablation (1,470 nm radial tip, continuous wave, vein diameter: 6 cm/8 cm/10 cm-power: 10 Watt-pullback speed: 2.2 mm/s, 1.7 mm/s, 1.3 mm/s-LEED: 45J/cm, 60J/cm, 75J/cm-EFE 25J/cm(2), respectively). Approximate 2 cm segments of the vein were left untreated, then histopathological examinations of the untouched segments (5 slices: level 1 - furthest segment, level 2 - nearest segment) for heat induced damage were performed. A total damage scoring system was established, including the presence of endothelial swelling, intimal thickening, cellular vacuolisation in the muscle layer, oedema in the tunica media, and extent of necrosis. At level 1, the furthest segment of the specimen, there was no significant difference between the laser and control group, while the total damage score of the radiofrequency group was significantly higher than the control group (p < 0.01). Radiofrequency group had higher total damage score compared to the laser group at level 1 (p < 0.01), 2 (p < 0.01), and 5 (p < 0.01); while no significant difference was observed at level 3 (p = 0.46) and 4 (p = 0.13). Significant heat induced damage may be seen even if the 2 cm segment of the vessel is left unablated. Radiofrequency ablation seems to cause more histological damage than laser ablation in this ex vivo study. Further in vivo studies are necessary, in order to validate these findings.

  8. Lasso catheter guided ablation for paroxysmal atrial fibrillation: the first experience in Thailand.

    PubMed

    Raungratanaamporn, Ongkarn; Bhurippanyo, Kiertijai; Chotinaiwattarakul, Chunhakasem; Suksap, Suthisak; Chirapastan, Anna; Ninmaneechot, Nuntaya; Numee, Malee

    2003-05-01

    The authors used the 10-pole pulmonary vein sized loop-shaped, lasso, catheter via a transatrial septal long sheath in 10 patients who had symptomatic refractory paroxysmal atrial fibrillation (PAF) in order to map and guide for catheter ablation. The radiofrequency current was delivered at the junction between atrial tissue and the pulmonary vein which was the earliest endocardial activation time of the premature atrial contraction (PAC) initiating the PAF and at the pulmonary vein potential during sinus rhythm. Twenty two foci of PAC, 10 and 7, 4 and 1 from left and right superior and left and right inferior pulmonary veins, respectively, and 5 pulmonary vein potentials, 2 and 3 from left and right superior pulmonary veins, respectively, were ablated. After AF ablation, classical atrial flutter (AFl) could be induced in 9 patients. Isthmus line of block for AFl was performed in all patients. Two patients had atrial tachycardia at the high right atrium and also successfully ablated. The mean fluoroscopic and procedure times were 87 and 300 minutes, respectively. One patient had deep vein thrombosis which resolved after anticoagulant therapy. One patient had recurrent PAF which was successfully reablated but he still had very mild symptoms. During the mean follow-up period of 5.8 months, 9 patients remained free of symptoms. Lasso catheter is an effective tool for mapping and guiding of ablation for PAF. However, more experience and long-term follow-up are required.

  9. Therapy of HCC-radiofrequency ablation.

    PubMed

    Buscarini, L; Buscarini, E

    2001-01-01

    Radiofrequency interstitial hyperthermia has been used for percutaneous ablation of hepatocellular carcinoma, under ultrasound guidance in local anesthesia. Conventional needle electrodes require a mean number of 3 sessions to treat tumors of diameter < or = 3 cm. Tumors up to 3.5 cm in diameter can be treated in 1 or 2 sessions by expandable needle electrodes. With both methods in all treated cases, ablation of tumors was obtained. In a group of patients with long follow-up, survival rate at 5 years was 40%. In a mean follow-up of 23 months 41% of patients had recurrences (local recurrences in 5%; new lesions in 36%), which often could be retreated by a new course of radiofrequency application. In recent experience large hepatocellular carcinomas (up to 6.8 cm in diameter) were treated by a combination of segmental transcatheter arterial embolization followed by radiofrequency application. In this way most tumors were ablated in one session of radiofrequency therapy. No fatal complications were observed. Major complications were: strong pain due to capsular necrosis in one patient; hemotorax in one case; a fluid collection in the site of ablated tumor in one patient treated by combination of transcatheter arterial embolization and radiofrequency application.

  10. A survey on monopolar radiofrequency treatment.

    PubMed

    Suh, Dong Hye; Hong, Eun Sun; Kim, Hyun Joo; Lee, Sang Jun; Kim, Hei Sung

    2017-08-14

    This questionnaire-based study was aimed to measure the level of appreciation, awareness of the special tips, and practice patterns of monopolar radiofrequency among Korean dermatologists practicing a specific monopolar radiofrequency device (Thermage® Inc., Hayward, CA). A total of 82 surveys were analyzed to show that the majority of participants (78.8%) were highly satisfied with the outcomes of monopolar radiofrequency treatment. All respondents were aware of the Eye Tip 0.25 cm(2) , and the majority knew the difference between the Face tip (blue) and the Total tip (orange). Most (86.3%) agreed to the statement that 900 shots were appropriate for facial tightening in those between the ages of 35 and 65 years. 66.2% of participants reported to have perform monopolar radiofrequency to extra-facial sites within the past year. As for the tips, the Total tip was most popular for all body sties and the Big tip was favored for the abdomen, thighs and buttock. We hope our data allow dermatologists to better utilize monopolar radiofrequency. © 2017 Wiley Periodicals, Inc.

  11. 21 CFR 870.1210 - Continuous flush catheter.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1210 Continuous flush catheter. (a) Identification. A continuous flush catheter is an attachment to a catheter-transducer system...

  12. 21 CFR 870.1210 - Continuous flush catheter.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1210 Continuous flush catheter. (a) Identification. A continuous flush catheter is an attachment to a catheter-transducer system...

  13. 21 CFR 870.1200 - Diagnostic intravascular catheter.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... intracardiac pressures, to sample blood, and to introduce substances into the heart and vessels. Included in this generic device are right-heart catheters, left-heart catheters, and angiographic catheters,...

  14. 21 CFR 870.1200 - Diagnostic intravascular catheter.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... intracardiac pressures, to sample blood, and to introduce substances into the heart and vessels. Included in this generic device are right-heart catheters, left-heart catheters, and angiographic catheters,...

  15. 21 CFR 870.1200 - Diagnostic intravascular catheter.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... intracardiac pressures, to sample blood, and to introduce substances into the heart and vessels. Included in this generic device are right-heart catheters, left-heart catheters, and angiographic catheters,...

  16. 21 CFR 870.1200 - Diagnostic intravascular catheter.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... intracardiac pressures, to sample blood, and to introduce substances into the heart and vessels. Included in this generic device are right-heart catheters, left-heart catheters, and angiographic catheters,...

  17. 21 CFR 870.1200 - Diagnostic intravascular catheter.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... intracardiac pressures, to sample blood, and to introduce substances into the heart and vessels. Included in this generic device are right-heart catheters, left-heart catheters, and angiographic catheters,...

  18. FAQs about Catheter-Associated Urinary Tract Infection

    MedlinePlus

    ... do to help prevent catheter-associated urinary tract infections if I have a catheter? • Always clean your hands before and after doing catheter care. • Always keep your urine bag below the level ...

  19. Nasal obstruction: comparison of radiofrequency with lateral displacement of the inferior turbinate and radiofrequency alone.

    PubMed

    Kaymakçi, Mustafa; Gur, Ozer Erdem; Ozdem, Cafer

    2014-01-01

    To compare the outcomes of the nasal obstruction, the main symptom of the patients who underwent radiofrequency and lateral displacement of the inferior turbinate and patients who were treated with radiofrequency alone. The prospective randomised study was conducted at the Department of Otorhinolaryngology and Head-Neck Surgery, Balikesir University Medical School, Balikesir, Turkey, between July and December 2012. It included 60 patients, diagnosed with allergic or non-allergic chronic rhinitis with inferior turbinate hypertrophy which was refractory to medical therapy. Half of the patients were treated with radiofrequency, and the rest with radiofrequency and lateral displacement. The main symptom of the patients was nasal obstruction. The frequency and degree of nasal obstruction were evaluated by patients' self-assessments using the standard 10-cm visual analogue scale. The evaluations were performed first pre-operatively and on the 1st, 3rd, 5th and 7th days postoperatively as well as at the end of the 4th week. SPSS 18 was used for statistical analysis. Nasal obstruction frequency and severity scores in patients treated with both radiofrequency and lateral displacement on post-operative days 3, 5 and 7 were found to be significantly lower (p<0.001) compared to the patients treated with only radiofrequency. The study demonstrated that radiofrequency and lateral displacement together is an effective method to prevent inferior turbinate oedema in the early post-operative period.

  20. The Gore-Tex peritoneal catheter: a clinical evaluation and comparison with the Tenckhoff catheter.

    PubMed

    Bay, W H; Vaccaro, P S; Powell, S L; Erlich, L F

    1984-11-01

    In January of 1983, the Gore-Tex (W.L. Gore & Associates, Inc, Flagstaff, Ariz) peritoneal catheter was introduced into the dialysis market. Presently, there is no other peritoneal catheter that offers this unique subcutaneous tunnel design. This catheter has an external and intra-abdominal Silastic (Dow Corning, Midland, Mich) segment and a transcutaneous segment with a flange and cuff of expanded polytetrafluoroethylene (PTFE). This catheter was designed to decrease the incidence of tunnel infections, catheter cuff extrusions, and exit site infections. The clinical experience with 57 Gore-Tex catheters and 47 Tenckhoff catheters at Ohio State University from May 1980 through April 1983 is presented. In addition, the Gore-Tex catheter's surgical insertion technique and postoperative care procedures are described. There was a significant decrease in the incidence of tunnel infections with the Gore-Tex catheter versus the Tenckhoff catheter (0.03 versus 0.21 infections per patient-year, respectively; P less than .05). There was no significant difference between the Gore-Tex catheter and the Tenckhoff catheter with regard to the patient peritonitis rate (1.12 versus 1.38 episodes of peritonitis per patient-year, respectively) or the exit site infection rate (0.65 versus 0.50 infections per patient-year, respectively). There were no cuff extrusions with the Gore-Tex catheter. The decrease in the incidence of tunnel infections with the Gore-Tex catheter suggests that the PTFE barrier inhibits longitudinal bacterial movement and avoids bacterial sequestration. Patients with repeat tunnel infections may benefit from a Gore-Tex catheter placement.

  1. Transurethral radiofrequency collagen denaturation for the treatment of women with urinary incontinence.

    PubMed

    Kang, Diana; Han, Julia; Neuberger, Molly M; Moy, M Louis; Wallace, Sheila A; Alonso-Coello, Pablo; Dahm, Philipp

    2015-03-18

    evidence using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach. We included in the analysis one small sham-controlled randomised trial of 173 women performed in the United States. Participants enrolled in this study had been diagnosed with stress UI and were randomly assigned to transurethral radiofrequency collagen denaturation (treatment) or a sham surgery using a non-functioning catheter (no treatment). Mean age of participants in the 12-month multi-centre trial was 50 years (range 22 to 76 years).Of three patient-important primary outcomes selected for this systematic review, the number of women reporting UI symptoms after intervention was not reported. No serious adverse events were reported for the transurethral radiofrequency collagen denaturation arm or the sham treatment arm during the 12-month trial. Owing to high risk of bias and imprecision, we downgraded the quality of evidence for this outcome to low. The effect of transurethral radiofrequency collagen denaturation on the number of women with an incontinence quality of life (I-QOL) score improvement ≥ 10 points at 12 months was as follows: RR 1.11, 95% CI 0.77 to 1.62; participants = 142, but the confidence interval was wide. For this outcome, the quality of evidence was also low as the result of high risk of bias and imprecision.We found no evidence on the number of women undergoing repeat continence surgery. The risk of other adverse events (pain/dysuria (RR 5.73, 95% CI 0.75 to 43.70; participants = 173); new detrusor overactivity (RR 1.36, 95% CI 0.63 to 2.93; participants = 173); and urinary tract infection (RR 0.95, 95% CI 0.24 to 3.86; participants = 173) could not be established reliably as the trial was small. Evidence was insufficient for assessment of whether use of transurethral radiofrequency collagen denaturation was associated with an increased rate of urinary retention, haematuria and hesitancy compared with sham treatment in 173 participants. The GRADE

  2. 47 CFR 2.801 - Radiofrequency device defined.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Radiofrequency device defined. 2.801 Section 2.801 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Marketing of Radio-frequency Devices § 2.801 Radiofrequency...

  3. 47 CFR 2.801 - Radiofrequency device defined.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Radiofrequency device defined. 2.801 Section 2.801 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Marketing of Radio-frequency Devices § 2.801 Radiofrequency...

  4. 47 CFR 2.801 - Radiofrequency device defined.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Radiofrequency device defined. 2.801 Section 2.801 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Marketing of Radio-frequency Devices § 2.801 Radiofrequency...

  5. 47 CFR 2.801 - Radiofrequency device defined.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Radiofrequency device defined. 2.801 Section 2.801 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Marketing of Radio-frequency Devices § 2.801 Radiofrequency...

  6. 47 CFR 2.801 - Radiofrequency device defined.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Radiofrequency device defined. 2.801 Section 2.801 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Marketing of Radio-frequency Devices § 2.801 Radiofrequency...

  7. 47 CFR 1.1310 - Radiofrequency radiation exposure limits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Radiofrequency radiation exposure limits. 1... Radiofrequency radiation exposure limits. (a) Specific absorption rate (SAR) shall be used to evaluate the environmental impact of human exposure to radiofrequency (RF) radiation as specified in § 1.1307(b) within...

  8. 47 CFR 1.1310 - Radiofrequency radiation exposure limits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Radiofrequency radiation exposure limits. 1... Procedures Implementing the National Environmental Policy Act of 1969 § 1.1310 Radiofrequency radiation... exposure to radiofrequency (RF) radiation as specified in § 1.1307(b), except in the case of...

  9. 47 CFR 1.1310 - Radiofrequency radiation exposure limits.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Radiofrequency radiation exposure limits. 1... Radiofrequency radiation exposure limits. (a) Specific absorption rate (SAR) shall be used to evaluate the environmental impact of human exposure to radiofrequency (RF) radiation as specified in § 1.1307(b) within...

  10. 47 CFR 1.1310 - Radiofrequency radiation exposure limits.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Radiofrequency radiation exposure limits. 1... Radiofrequency radiation exposure limits. The criteria listed in table 1 shall be used to evaluate the environmental impact of human exposure to radiofrequency (RF) radiation as specified in § 1.1307(b), except...

  11. Modeling bipolar phase-shifted multielectrode catheter ablation.

    PubMed

    Tungjitkusolmun, Supan; Haemmerich, Dieter; Cao, Hong; Tsai, Jang-zern; Choy, Young Bin; Vorperian, Vicken R; Webster, John G

    2002-01-01

    Atrial fibrillation (AFIB) is a common clinical problem affecting approximately 0.5-1% of the United States population. Radio-frequency (RF) multielectrode catheter (MEC) ablation has successes in curing AFIB. We utilized finite-element method analysis to determine the myocardial temperature distribution after 30 s, 80 degrees C temperature-controlled unipolar ablation using three 7F 12.5-mm electrodes with 2-mm interelectrode spacing MEC. Numerical results demonstrated that cold spots occurred at the edges of the middle electrode and hot spots at the side electrodes. We introduced the bipolar phase-shifted technique for RF energy delivery of MEC ablation. We determined the optimal phase-shift (phi) between the two sinusoidal voltage sources of a simplified two-dimensional finite-element model. At the optimal phi, we can achieve a temperature distribution that minimizes the difference between temperatures at electrode edges. We also studied the effects of myocardial electric conductivity (sigma), thermal conductivity (k), and the electrode spacing on the optimal phi. When we varied sigma and kappa from 50% to 150%, optimal phi ranged from 29.5 degrees to 23.5 degrees, and in the vicinity of 26.5 degrees, respectively. The optimal phi for 3-mm spacing MEC was 30.5 degrees. We show the design of a simplified bipolar phase-shifted MEC ablation system.

  12. Successful retrieval of an irretrievable jugular tesio catheter using a fogarty arterial embolectomy catheter.

    PubMed

    Arnáiz-García, María Elena; Gutiérrez-Diez, Francisco; Arnáiz-García, Ana María; Arnáiz, Javier; Expósito, Víctor; Nistal, Juan Francisco; Rodríquez-Entem, Felipe; Olalla, Juan José; López-Rodríguez, Javier; González-Santos, José María

    2014-05-01

    Long life expectancy and wide development of therapies have increased the number of patients under artificial treatment for lost kidney function or dialysis. Different options for vascular access are suitable for receiving this therapy. The use of tunneled catheters has consequently increased complications related to its use. A difficult retrieval of catheters caused by a hard fibrin sheath along its trajectory is a common drawback. Herein, we report a woman with suspicion of hemodialysis catheter infection and an irretrievable Tesio catheter. A novel technique using a Fogarty arterial catheter allowed a successful retrieval and avoided an aggressive management.

  13. Radiofrequency uvulopalatoplasty for primary snoring.

    PubMed

    Samimi Ardestani, Seyed Hadi; Dadgarnia, Mohammad Hossein; Baradaranfar, Mohammad Hossein; Mazidi, Mona; Rabbani, Mahtab; Behniafard, Nasim; Baradaranfar, Amin

    2013-09-09

    Simple snoring is a social problem, one that can gravely affect the patient's married life. About 40% of men and 20% of women are affected, and it often goes along with sleep-disordered breathing. Up to now various surgical techniques have been defined such as UPPP(uvulopalatopharyngo plasty), and laser-assisted uvulopalatoplasty (LAUP). Among the surgical methods, RAUP (radiofrequency assisted uvulopalatoplasty) is a minimal invasive, an easy performed, and time and cost effective one. We designed a before and after a clinical trial. The inclusion criteria were age >18 years, complaint of nocturnal snoring, have a bed partner to assess snoring, AHI<5 events per hour in the polysomnography, malampathy score (soft palate position) I or II, an elongated uvula, grade I and II of pharyngeal webbing and patient consent was needed too. A 10-score visual analog scale (VAS) of snoring severity was completed by bed partner. All of 35 included patients underwent RAUP under local anesthesia by the same expert surgeon. After 3 months, 6 months and one year, subjective snoring decreased significantly compared to the preoperative period. The decline in VAS in 6 month compared to 3 months postoperatively, was not significant (P=0.223). When comparing 1 year and 6 months after treatment, the VAS scores were increased, but they were not significant (From 1.8 to 1.9, P=0.78). Three months after treatment minor complications consisted of: nasal regurgitation in 2 patients (5.7%), nasal speech in 2 (5.7%) and exacerbation of snoring in 2 (5.7%) patients.There was no major complication including mucosal laceration, uvular damage and obstruction of the airway. The rate of snoring decrease did not correlate with age, sex and BMI. Based on this study and literature review, it seems RAUP is a safe surgery, which may decrease symptoms of snoring, at least, in short-term follow-up.

  14. Living with a long-term, indwelling urinary catheter: catheter users' experience.

    PubMed

    Fowler, Sarah; Godfrey, Helen; Fader, Mandy; Timoney, Anthony Gerard; Long, Adele

    2014-01-01

    The purpose of this study was to explore the experiences of long-term catheter users within a heterogeneous population. The sample comprised 27 community-dwelling long-term catheter users. Participants included 14 female users (4 urethral, 10 suprapubic catheter) and 13 male users (6 urethral, 7 suprapubic) between 22 and 96 years of age. Interviews were conducted in participants' homes except 1, which took place in a urology outpatient department based on the participant's preference. A qualitative research design using an interpretive description approach was used for data collection and analysis. All interviews were electronically recorded and transcribed verbatim. Interpretive description involved familiarization with the data, thematic analysis, and the development of an interpretive account. The impact of the catheter and daily living adjustments that catheter users made are captured within 8 themes: (1) making adjustments; (2) managing away from home; (3) nighttime adjustment; (4) catheter problems; (5) social interaction; (6) support from others; (7) unpredictability; and (8) intimacy and body image. Catheter users' experiences of living with a catheter are shaped by a variety of interrelated factors. Some participants were determined to overcome catheter-related problems and develop self-reliance while others adopted a more resigned approach to living with a catheter. Having a catheter enabled some participants to experience greater freedom while others led more restricted lives as a consequence of catheterization.

  15. Hemodynamic change in pulmonary vein stenosis after radiofrequency ablation: assessment with magnetic resonance angiography.

    PubMed

    Yun, Doyoung; Jung, Jung Im; Oh, Yong Seog; Youn, Ho-Joong

    2012-01-01

    We present a case of pulmonary vein (PV) stenosis after radio-frequency (RF) ablation, in which a hemodynamic change in the pulmonary artery was similar to that of congenital PV atresia on time-resolved contrast-enhanced magnetic resonance angiography (TR-MRA). A 48-year-old man underwent RF ablation due to atrial fibrillation. The patient subsequently complained of hemoptysis, dyspnea on exertion, and right chest pain. Right PV stenosis after catheter ablation was diagnosed through chest computed tomography and lung perfusion scan. Pulmonary TR-MRA revealed the pulmonary artery via systemic arterial collaterals and draining systemic collateral veins. On a velocity-encoded cine image, the flow direction of the right pulmonary artery was reversed in the diastolic phase and the left pulmonary artery demonstrated continuous forward flow throughout the cardiac cycle. These hemodynamic changes were similar to those seen in congenital unilateral PV atresia.

  16. Radiofrequency Ablation of Left Atrial Reentrant Tachycardias in Rheumatic Mitral Valve Disease: A Case Series.

    PubMed

    Prabhu, Mukund A; Thajudeen, Anees; Vk, Ajit Kumar; J, Tharakan; B V, Prasad Srinivas; Namboodiri, Narayanan

    2017-01-01

    Left atrial (LA) reentrant tachycardias are not uncommon in regions where rheumatic heart disease is prevalent. Some of these arrhythmias may be curable by radiofrequency ablation (RFA). However, there are limited data pertaining to this in existing literature. Three patients who had rheumatic mitral valve disease with past history of surgical-/catheter-based intervention and having no significant residual disease had symptomatic atrial flutter despite optimal medical management. An electrophysiological study confirmed an LA focal/micro-reentrant mechanism in all. There was patchy scarring of the LA, and successful RFA of these arrhythmias could be achieved. The focal nature of the scar in these patients may suggest that the rheumatic involvement of the atrium or the hemodynamic consequence of the vulvar lesion causes nonuniform insult to the atrial tissue and limited scar. At least in some patients with limited scarring, early RFA may help in the maintenance of sinus rhythm. © 2016 Wiley Periodicals, Inc.

  17. [Pliability and deflection of diagnostic catheters].

    PubMed

    Pelyhe, Liza; Bognár, Eszter

    2014-09-28

    The cardiac catheter is an intravascular catheter, which is introduced or implanted into the heart for diagnostic or therapeutic reasons. The catheters may break or king during their introduction and/or removal. The aim of the authors was to study the pliability of two catheters with the same material but different diameters according to the Food and Drug Administration's recommendation. The bending points, diameter decrease, deflection, and their correlation and dependence on the distance from the tip, as well as the influence of the initial diameter of the catheters were determined. The bending of catheters was performed on 9 bending points (120-280 mm from the tip by 20 mm) on 16 gauges with different radius (10-2.5 mm by 0.5 mm). A linear dependency between the diameter decrease and deflection was observed, which was independent from the placement of the measurement in both catheters examined. The larger initial diameter had significant (p = 0.05) greater diameter decrease than the smaller, but the curves characteristic of the diameter decrease and deflection were similar. The applied method seems to be useful for the examination of weak points of cardiac catheters.

  18. Automated Pointing of Cardiac Imaging Catheters

    PubMed Central

    Loschak, Paul M.; Brattain, Laura J.; Howe, Robert D.

    2013-01-01

    Intracardiac echocardiography (ICE) catheters enable high-quality ultrasound imaging within the heart, but their use in guiding procedures is limited due to the difficulty of manually pointing them at structures of interest. This paper presents the design and testing of a catheter steering model for robotic control of commercial ICE catheters. The four actuated degrees of freedom (4-DOF) are two catheter handle knobs to produce bi-directional bending in combination with rotation and translation of the handle. An extra degree of freedom in the system allows the imaging plane (dependent on orientation) to be directed at an object of interest. A closed form solution for forward and inverse kinematics enables control of the catheter tip position and the imaging plane orientation. The proposed algorithms were validated with a robotic test bed using electromagnetic sensor tracking of the catheter tip. The ability to automatically acquire imaging targets in the heart may improve the efficiency and effectiveness of intracardiac catheter interventions by allowing visualization of soft tissue structures that are not visible using standard fluoroscopic guidance. Although the system has been developed and tested for manipulating ICE catheters, the methods described here are applicable to any long thin tendon-driven tool (with single or bi-directional bending) requiring accurate tip position and orientation control. PMID:24683501

  19. Robust pigtail catheter tip detection in fluoroscopy

    NASA Astrophysics Data System (ADS)

    Tzoumas, Stratis; Wang, Peng; Zheng, Yefeng; John, Matthias; Comaniciu, Dorin

    2012-02-01

    The pigtail catheter is a type of catheter inserted into the human body during interventional surgeries such as the transcatheter aortic valve implantation (TAVI). The catheter is characterized by a tightly curled end in order to remain attached to a valve pocket during the intervention, and it is used to inject contrast agent for the visualization of the vessel in fluoroscopy. Image-based detection of this catheter is used during TAVI, in order to overlay a model of the aorta and enhance visibility during the surgery. Due to the different possible projection angles in fluoroscopy, the pigtail tip can appear in a variety of different shapes spanning from pure circular to ellipsoid or even line. Furthermore, the appearance of the catheter tip is radically altered when the contrast agent is injected during the intervention or when it is occluded by other devices. All these factors make the robust real-time detection and tracking of the pigtail catheter a challenging task. To address these challenges, this paper proposes a new tree-structured, hierarchical detection scheme, based on a shape categorization of the pigtail catheter tip, and a combination of novel Haar features. The proposed framework demonstrates improved detection performance, through a validation on a data set consisting of 272 sequences with more than 20,000 images. The detection framework presented in this paper is not limited to pigtail catheter detection, but it can also be applied successfully to any other shape-varying object with similar characteristics.

  20. 21 CFR 870.1300 - Catheter cannula.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Catheter cannula. 870.1300 Section 870.1300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1300 Catheter cannula. (a...

  1. 21 CFR 870.1380 - Catheter stylet.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Catheter stylet. 870.1380 Section 870.1380 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1380 Catheter stylet. (a...

  2. 21 CFR 870.1300 - Catheter cannula.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Catheter cannula. 870.1300 Section 870.1300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1300 Catheter cannula. (a...

  3. 21 CFR 870.1250 - Percutaneous catheter.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Percutaneous catheter. 870.1250 Section 870.1250 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1250 Percutaneous catheter...

  4. 21 CFR 870.1280 - Steerable catheter.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Steerable catheter. 870.1280 Section 870.1280 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1280 Steerable catheter. (a...

  5. 21 CFR 870.1250 - Percutaneous catheter.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Percutaneous catheter. 870.1250 Section 870.1250 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1250 Percutaneous catheter...

  6. 21 CFR 870.1340 - Catheter introducer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Catheter introducer. 870.1340 Section 870.1340 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1340 Catheter introducer...

  7. 21 CFR 870.1340 - Catheter introducer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Catheter introducer. 870.1340 Section 870.1340 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1340 Catheter introducer...

  8. 21 CFR 870.1250 - Percutaneous catheter.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Percutaneous catheter. 870.1250 Section 870.1250 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1250 Percutaneous catheter...

  9. 21 CFR 870.1380 - Catheter stylet.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Catheter stylet. 870.1380 Section 870.1380 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1380 Catheter stylet. (a...

  10. 21 CFR 870.1280 - Steerable catheter.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Steerable catheter. 870.1280 Section 870.1280 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1280 Steerable catheter. (a...

  11. 21 CFR 870.1380 - Catheter stylet.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Catheter stylet. 870.1380 Section 870.1380 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1380 Catheter stylet. (a...

  12. 21 CFR 870.1380 - Catheter stylet.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Catheter stylet. 870.1380 Section 870.1380 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1380 Catheter stylet. (a...

  13. 21 CFR 870.1280 - Steerable catheter.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Steerable catheter. 870.1280 Section 870.1280 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1280 Steerable catheter. (a...

  14. 21 CFR 870.1280 - Steerable catheter.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Steerable catheter. 870.1280 Section 870.1280 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1280 Steerable catheter. (a...

  15. 21 CFR 870.1300 - Catheter cannula.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Catheter cannula. 870.1300 Section 870.1300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1300 Catheter cannula. (a...

  16. 21 CFR 870.1340 - Catheter introducer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Catheter introducer. 870.1340 Section 870.1340 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1340 Catheter introducer...

  17. 21 CFR 870.1300 - Catheter cannula.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Catheter cannula. 870.1300 Section 870.1300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1300 Catheter cannula. (a...

  18. 21 CFR 870.1300 - Catheter cannula.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Catheter cannula. 870.1300 Section 870.1300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1300 Catheter cannula. (a...

  19. 21 CFR 870.1380 - Catheter stylet.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Catheter stylet. 870.1380 Section 870.1380 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1380 Catheter stylet. (a...

  20. Haemodialysis catheters in the intensive care unit.

    PubMed

    Huriaux, Laetitia; Costille, Paul; Quintard, Hervé; Journois, Didier; Kellum, John A; Rimmelé, Thomas

    2016-11-29

    Ten to 15% of critically ill patients need renal replacement therapy (RRT) for severe acute kidney injury. The dialysis catheter is critical for RRT quality and efficiency. Catheters have several properties that must be optimized to promote RRT success. The distal tip has to be located in a high blood flow location, which means central venous territory. Therefore, catheters are mostly inserted into the right internal jugular vein or in femoral veins. External diameter should vary from 12 to 16 Fr in order to ensure adequate blood flow inside the catheter. Lumen shapes are theoretically designed to limit thrombotic risk with low turbulences and frictional forces against the internal wall. With low aspiration pressure, distal tip shape has to deliver sufficient blood flow, while limiting recirculation rate. Catheter material should be biocompatible. Despite in vitro data, no strong evidence supports the use of coated catheters in the ICU in order to reduce infectious risk. Antibiotic "lock" solutions are not routinely recommended. Ultrasound guidance for catheterization significantly decreases mechanical complications. Clinicians should select the optimal catheter according to patient body habitus, catheter intrinsic properties and RRT modality to be used.

  1. 21 CFR 874.4175 - Nasopharyngeal catheter.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nasopharyngeal catheter. 874.4175 Section 874.4175 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Surgical Devices § 874.4175 Nasopharyngeal catheter....

  2. 21 CFR 874.4175 - Nasopharyngeal catheter.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nasopharyngeal catheter. 874.4175 Section 874.4175 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Surgical Devices § 874.4175 Nasopharyngeal catheter....

  3. 21 CFR 874.4175 - Nasopharyngeal catheter.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nasopharyngeal catheter. 874.4175 Section 874.4175 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Surgical Devices § 874.4175 Nasopharyngeal catheter....

  4. Radio-frequency characteristics of graphene oxide

    NASA Astrophysics Data System (ADS)

    Kim, Whan Kyun; Jung, Young Mo; Cho, Joon Hyong; Kang, Ji Yoong; Oh, Ju Yeong; Kang, Hosung; Lee, Hee-Jo; Kim, Jae Hun; Lee, Seok; Shin, H. J.; Choi, J. Y.; Lee, S. Y.; Kim, Y. C.; Han, I. T.; Kim, J. M.; Yook, Jong-Gwan; Baik, Seunghyun; Jun, Seong Chan

    2010-11-01

    We confirm graphene oxide, a two-dimensional carbon structure at the nanoscale level can be a strong candidate for high-efficient interconnector in radio-frequency range. In this paper, we investigate high frequency characteristics of graphene oxide in range of 0.5-40 GHz. Radio-frequency transmission properties were extracted as S-parameters to determine the intrinsic ac transmission of graphene sheets, such as the impedance variation dependence on frequency. The impedance and resistance of graphene sheets drastically decrease as frequency increases. This result confirms graphene oxide has high potential for transmitting signals at gigahertz ranges.

  5. Laser welding of balloon catheters

    NASA Astrophysics Data System (ADS)

    Flanagan, Aidan J.

    2003-03-01

    The balloon catheter is one of the principal instruments of non-invasive vascular surgery. It is used most commonly for angioplasty (and in recent years for delivering stents) at a multitude of different sites in the body from small arteries in the heart to the bilary duct. It is composed of a polymer balloon that is attached to a polymer shaft at two points called the distal and proximal bonds. The diverse utility of balloon catheters means a large range of component sizes and materials are used during production; this leads to a complexity of bonding methods and technology. The proximal and distal bonds have been conventionally made using cyanoacrylate or UV curing glue, however with performance requirements of bond strength, flexibility, profile, and manufacturing costs these bonds are increasingly being made by welding using laser, RF, and Hot Jaw methods. This paper describes laser welding of distal and proximal balloon bonds and details beam delivery, bonding mechanisms, bond shaping, laser types, and wavelength choice.

  6. Whole shaft visibility and mechanical performance for active MR catheters using copper-nitinol braided polymer tubes

    PubMed Central

    Kocaturk, Ozgur; Saikus, Christina E; Guttman, Michael A; Faranesh, Anthony Z; Ratnayaka, Kanishka; Ozturk, Cengizhan; McVeigh, Elliot R; Lederman, Robert J

    2009-01-01

    Background Catheter visualization and tracking remains a challenge in interventional MR. Active guidewires can be made conspicuous in "profile" along their whole shaft exploiting metallic core wire and hypotube components that are intrinsic to their mechanical performance. Polymer-based catheters, on the other hand, offer no conductive medium to carry radio frequency waves. We developed a new "active" catheter design for interventional MR with mechanical performance resembling braided X-ray devices. Our 75 cm long hybrid catheter shaft incorporates a wire lattice in a polymer matrix, and contains three distal loop coils in a flexible and torquable 7Fr device. We explored the impact of braid material designs on radiofrequency and mechanical performance. Results The incorporation of copper wire into in a superelastic nitinol braided loopless antenna allowed good visualization of the whole shaft (70 cm) in vitro and in vivo in swine during real-time MR with 1.5 T scanner. Additional distal tip coils enhanced tip visibility. Increasing the copper:nitinol ratio in braiding configurations improved flexibility at the expense of torquability. We found a 16-wire braid of 1:1 copper:nitinol to have the optimum balance of mechanical (trackability, flexibility, torquability) and antenna (signal attenuation) properties. With this configuration, the temperature increase remained less than 2°C during real-time MR within 10 cm horizontal from the isocenter. The design was conspicuous in vitro and in vivo. Conclusion We have engineered a new loopless antenna configuration that imparts interventional MR catheters with satisfactory mechanical and imaging characteristics. This compact loopless antenna design can be generalized to visualize the whole shaft of any general-purpose polymer catheter to perform safe interventional procedures. PMID:19674464

  7. Cost/benefit analysis of chlorhexidine-silver sulfadiazine-impregnated venous catheters for femoral access.

    PubMed

    Lorente, Leonardo; Lecuona, María; Jiménez, Alejandro; Lorenzo, Lisset; Diosdado, Sara; Marca, Lucía; Mora, María L

    2014-10-01

    Sixty-four patients with chlorhexidine-silver sulfadiazine-impregnated catheters had a lower rate of catheter-related bloodstream infection and lower central venous catheter-related costs per catheter day than 190 patients with a standard catheter.

  8. Catheter-related urinary tract infection.

    PubMed

    Nicolle, Lindsay E

    2005-01-01

    Indwelling urinary catheters are used frequently in older populations. For either short- or long-term catheters, the infection rate is about 5% per day. Escherichia coli remains the most common infecting organism, but a wide variety of other organisms may be isolated, including yeast species. Bacteria tend to show increased resistance because of the repeated antimicrobial courses. Urinary tract infection (UTI) usually follows formation of biofilm on both the internal and external catheter surface. The biofilm protects organisms from both antimicrobials and the host immune response. Morbidity from UTI with short-term catheter use is limited if appropriate catheter care is practised. In patients with long-term catheters, fever from a urinary source is common with a frequency varying from 1 per 100 to 1 per 1000 catheter days. Long-term care facility residents with chronic indwelling catheters have a much greater risk for bacteraemia and other urinary complications than residents without catheters. Asymptomatic catheter-acquired UTI should not be treated with antimicrobials. Antimicrobial treatment does not decrease symptomatic episodes but will lead to emergence of more resistant organisms. For treatment of symptomatic infection, many antimicrobials are effective. Wherever possible, antimicrobial selection should be delayed until culture results are available. Whether to administer initial treatment by an oral or parenteral route is determined by clinical presentation. If empirical therapy is required, antimicrobial selection is based on variables such as route of administration, anticipated infecting organism and susceptibility, and patient tolerance. Renal function, concomitant medications, local formulary and cost may also be considered in selection of the antimicrobial agent. The duration of therapy is usually 10-14 days, but patients who respond promptly and in whom the catheter must remain in situ may be treated with a shorter 7-day course to reduce

  9. Development of Bend Sensor for Catheter Tip

    NASA Astrophysics Data System (ADS)

    Nagano, Yoshitaka; Sano, Akihito; Fujimoto, Hideo

    Recently, a minimally invasive surgery which makes the best use of the catheter has been becoming more popular. In endovascular coil embolization for a cerebral aneurysm, the observation of the catheter's painting phenomenon is very important to execute the appropriate manipulation of the delivery wire and the catheter. In this study, the internal bend sensor which consists of at least two bending enhanced plastic optical fibers was developed in order to measure the curvature of the catheter tip. Consequently, the painting could be more sensitively detected in the neighborhood of the aneurysm. In this paper, the basic characteristics of the developed sensor system are described and its usefulness is confirmed from the comparison of the insertion force of delivery wire and the curvature of catheter tip in the experiment of coil embolization.

  10. Intraluminal fluorescence spectroscopy catheter with ultrasound guidance

    NASA Astrophysics Data System (ADS)

    Stephens, Douglas N.; Park, Jesung; Sun, Yang; Papaioannou, Thanassis; Marcu, Laura

    2009-05-01

    We demonstrate the feasibility of a time-resolved fluorescence spectroscopy (TRFS) technique for intraluminal investigation of arterial vessel composition under intravascular ultrasound (IVUS) guidance. A prototype 1.8-mm (5.4 Fr) catheter combining a side-viewing optical fiber (SVOF) and an IVUS catheter was constructed and tested with in vitro vessel phantoms. The prototype catheter can locate a fluorophore in the phantom vessel wall, steer the SVOF in place, perform blood flushing under flow conditions, and acquire high-quality TRFS data using 337-nm wavelength excitation. The catheter steering capability used for the coregistration of the IVUS image plane and the SVOF beam produce a guiding precision to an arterial phantom wall site location of 0.53+/-0.16 mm. This new intravascular multimodal catheter enables the potential for in vivo arterial plaque composition identification using TRFS.

  11. Prevention of central venous catheter bloodstream infections.

    PubMed

    Walz, J Matthias; Memtsoudis, Stavros G; Heard, Stephen O

    2010-01-01

    The majority of nosocomial bloodstream infections in critically ill patients originate from an infected central venous catheter (CVC). Catheter-related bloodstream infections (CRBSIs) cause significant morbidity and mortality and increase the cost of care. The most frequent causative organisms for CRBSI are coagulase-negative staphylococci (CoNSs), Staphylococcus aureus, enterococci, and Candida species. The path to infection frequently includes migration of skin organisms at the insertion site into the cutaneous catheter tract, resulting in microbial colonization of the catheter tip and formation of biofilm. Evidence-based strategies for the prevention of CRBSI include behavioral and educational interventions, effective skin antisepsis coupled with maximum barrier precautions, the use of antiseptic dressings, and the use of antiseptic or antibiotic impregnated catheters. Achieving and maintaining very low rates of CRBSI requires a multidisciplinary approach involving the entire health care team, the use of novel technologies in patients with the highest risk of CRBSI, and frequent reeducation of staff.

  12. [Catheter ablation in supraventricular tachycardia].

    PubMed

    Pitschner, H F; Neuzner, J

    1996-01-01

    The first report about successful radio frequency ablation of a right-posterior-septal accessory pathway appeared in 1986. Since then, the technology of both guidable ablation catheters and radio frequency generators has been considerably improved in an initially clinical-experimental phase. At the same time, electrophysiologists were equally able to enlarge their knowledge in the field of signal characteristics of arrhythmogenic substrates. This included the discovery of action potentials of accessory pathways (preexcitation syndromes), the location of fast and slow AV node conduction (AV nodal reentrant tachycardia, AVNRT), the functional importance of the anatomical isthmus between the os of the coronary sinus, the tricuspid valve and the inferior caval vein (atrial flutter). Mapping techniques such as transient and concealed entrainment became, among others, significant tools in finding the best localization for radio frequency catheter ablation. Thus, technical development and the increased knowledge of clinical electrophysiologists resulted in firmly establishing the procedure of catheter ablation as the method of first choice in the curative treatment of supraventricular tachycardias in a potential collective of about 5 per mill of the normal population (without atrial fibrillation). Supraventricular tachycardias with a reentry mechanism in the broadest sense (> 95% of all pts. with SVT) and those with focal automaticity (< 5%) occur as atrial fibrillation or atrial flutter in about 60% of all pts. (4-6 per mill of the normal population). Manifestation of the remaining reentrant tachycardias is mainly in the form of AVNRT (retrograde conduction via the fast pathway > 90% versus uncommon type < 10%). AV reentry via accessory pathways is found in about 15%, with orthodromic conduction via the AV node (> 90%). Atrial reentrant tachycardias are rather rare (with the exception of atrial fibrillation/flutter). The literature suggests medical therapy to be

  13. Atrioventricular nodal reentrant tachycardia ablation with radiofrequency energy during ongoing tachycardia: is it feasible?

    PubMed Central

    Kilic, Ayhan; Kabul, Kutsi; Unlu, Murat

    2014-01-01

    Introduction Radiofrequency (RF) ablation of the slow pathway for treatment of atrioventricular nodal reentrant tachycardia (AVNRT) is conventionally performed during sinus rhythm. Aim To evaluate the clinical and electrophysiological features and the short- and long-term results of slow pathway RF ablation during ongoing AVNRT. Material and methods A total of 282 consecutive patients with AVNRT undergoing RF catheter ablation were analysed. Patients whose tachycardia episodes could not be controlled during RF energy application and who underwent slow pathway ablation or modification during ongoing tachycardia formed the study group (group 1, n = 16) and those ablated during sinus rhythm formed the control group (group 2, n = 266). Results Of the clinical characteristics, only the frequency of tachycardia attacks was higher in group 1 (3.3 ±1.2 vs. 2.1 ±0.9 attacks/month, p < 0.001). Among the baseline electrophysiological measurements, the echo zone lasted significantly longer in group 1 than in group 2 (78 ±25 ms vs. 47 ±18 ms; p < 0.001). The immediate procedural success rate was 100% in both groups. There were no significant differences between groups regarding the mean number of radiofrequency energy applications (5.2 ±4.2 vs. 5.8 ±3.9), total procedure times (42.4 ±30.5 min vs. 40.2 ±29.4 min) and fluoroscopy times (11.4 ±8.5 min vs. 12.2 ±9.3 min) (p > 0.050 for all). All patients were followed-up for 29 ±7 months; only 2 patients (< 1%) in group 2 recurred (p > 0.050). No permanent atrioventricular block was observed. Conclusions The RF catheter ablation or modification of the slow pathway during ongoing AVNRT is feasible with acceptable short- and long-term efficacy and safety. However, this approach needs to be clarified with large-scale studies. PMID:25489328

  14. Evaluation of an intravenous catheter for use in the horse.

    PubMed

    Gulick, B A; Meagher, D M

    1981-02-01

    A commercially available polyvinyl chloride intravenous catheter was studied in 9 horses for 3 to 10 days to evaluate the catheter's suitability for use in the horse, to develop a new insertion technique, and to establish a protocol for catheter care. Seven of the animals were clinically normal horses receiving parenteral nutrition; one was a horse with hypocalcemia receiving frequent intravenous injections of calcium gluconate, and one was a clinically normal horse receiving no infusions. The catheter dressings were changed every 48 hours, and an aspirate from the catheter and the catheter tip was cultured at the time of catheter removal. One catheter became infected following a break in the protocol. It was concluded that the polyvinyl catheter is suitable for use in the horse and that the proposed protocol for catheter insertion and maintenance may reduce the likelihood of complications such as catheter sepsis, thrombophlebitis, and embolism.

  15. Radiological Interventions for Correction of Central Venous Port Catheter Migrations

    SciTech Connect

    Gebauer, Bernhard Teichgraeber, Ulf Karl; Podrabsky, Petr; Werk, Michael; Haenninen, Enrique Lopez; Felix, Roland

    2007-07-15

    Purpose. The purpose of this study was to evaluate radiological-interventional central venous port catheter corrections in migrated/malpositioned catheter tips. Materials and Methods. Thirty patients with migrated/malpositioned port catheter tips were included in this retrospective analysis. To visualize the catheter patency a contrast-enhanced port catheter series was performed, followed by transfemoral port catheter correction with various 5-F angiographic catheters (pigtail; Sos Omni), gooseneck snares, or combinations thereof. Results. One patient showed spontaneous reposition of the catheter tip. In 27 of 29 patients (93%), radiological-interventional port catheter correction was successful. In two patients port catheter malposition correction was not possible, because of the inability to catch either the catheter tip or the catheter in its course, possibly due to fibrin sheath formation with attachment of the catheter to the vessel wall. No disconnection or port catheter dysfunction was observed after correction. Conclusions. We conclude that in migrated catheter tips radiological-interventional port catheter correction is a minimally invasive alternative to port extraction and reimplantation. In patients with a fibrin sheath and/or thrombosis port catheter correction is often more challenging.

  16. Variations in epidural catheter manufacture: implications for bending and stiffness.

    PubMed

    Eckmann, David M

    2003-01-01

    There is no formal evaluation method used to relate epidural catheter design and manufacture to clinical outcomes, such as subarachnoid or intravascular catheter placement. We analyzed catheter bending stiffness to determine the range of stiffness of catheters commonly used. We hypothesized that catheter material has a greater influence on stiffness than does cross-sectional shape. We determined the elastic modulus by axial load testing and the area moment of inertia using calibrated microscopic measurements of cross-sectional geometry for 6 different catheter types, including 2 types of wire styletted catheters. We calculated bending stiffness as the product of the elastic modulus and the area moment of inertia. Catheters had similar area moments of inertia, but markedly different elastic moduli. Nylon and polyurethane catheters had the same bending stiffness, which was twice as high as that of coil reinforced catheters (P <.05), but 35% lower than that of radiopaque catheters (P <.05). Nylon and radiopaque wire styletted catheters had similar bending stiffness, which were 23-fold to 90-fold greater than that of the nonstyletted catheters (P <.05). Catheters currently available establish the range of bending stiffness that should not be exceeded, only optimized to clinical outcome. Clinical studies are needed to correlate the incidence of unintentional intravascular or subarachnoid catheter placement or migration and bending stiffness. Catheter technology improvements may enhance safety and increase the likelihood of successful catheter insertion, maintenance, and removal.

  17. Exclusion of fluoroscopy use in catheter ablation procedures: six years of experience at a single center.

    PubMed

    Fernández-Gómez, Juan M; Moriña-Vázquez, Pablo; Morales, Elena Del Rio; Venegas-Gamero, José; Barba-Pichardo, Rafael; Carranza, Manuel Herrera

    2014-06-01

    Nonfluoroscopic mapping systems have demonstrated significant reduction of radiation exposure in radiofrequency (RF) catheter ablation procedures. However, their use as only imaging guide is still limited. To evaluate the usefulness of a completely nonfluoroscopic approach to catheter ablation of supraventricular arrhythmias using the Ensite-NavX™ electroanatomical navigation system. During 6 years, all consecutive patients referred for RF catheter ablation of regular supraventricular tachycardia (SVT) were admitted for a "zero-fluoroscopy" approach and studied prospectively. The only exclusion criterion was the need to perform a transseptal puncture. A total of 340 procedures were performed on 328 patients (179 men, age 55.7 ± 18.6 years). One hundred fifty-three patients had typical atrial flutter (AFL), 146 had AV nodal reentrant tachycardia (AVNRT), 35 had AV reciprocating tachycardia (AVRT), 4 patients had incisional atrial flutter (IAF), and 2 had focal atrial tachycardia (AT). Procedural success was achieved in 337 of the cases (99.1%). In 322 (94.7%), the procedure was completed without any fluoroscopy use. Mean procedure time was 110.5 ± 51.8 minutes. Mean RF application time was 9.8 ± 12.8 minutes and the number of RF lesions was 16.43 ± 15.8. Only 1 major complication related to vascular access was recorded. During follow-up, there were 12 recurrences (3.5%) (8 patients from the AVNRT group, 4 patients from the AP group). RF catheter ablation of SVT with an approach completely guided by the NavX system and without use of fluoroscopy is feasible, safe, and effective. © 2014 Wiley Periodicals, Inc.

  18. Catheter Ablation of Pediatric Focal Atrial Tachycardia: Ten-Year Experience Using Modern Mapping Systems.

    PubMed

    Dieks, Jana-K; Müller, Matthias J; Schneider, Heike E; Krause, Ulrich; Steinmetz, Michael; Paul, Thomas; Kriebel, Thomas

    2016-03-01

    Experience of catheter ablation of pediatric focal atrial tachycardia (FAT) is still limited. There are data which were gathered prior to the introduction of modern 3D mapping and navigation systems into the clinical routine. Accordingly, procedures were associated with significant fluoroscopy and low success rates. The aim of this study was to present clinical and electrophysiological details of catheter ablation of pediatric FAT using modern mapping systems. Since March 2003, 17 consecutive patients <20 years underwent electrophysiological study (EPS) for FAT using the NavX(®) system (n = 7), the non-contact mapping system (n = 6) or the LocaLisa(®) system (n = 4), respectively. Radiofrequency was the primary energy source; cryoablation was performed in selected patients with a focus close to the AV node. In 16 patients, a total number of 19 atrial foci (right-sided n = 13, left-sided n = 6) could be targeted. In the remaining patient, FAT was not present/inducible during EPS. On an intention-to-treat basis, acute success was achieved in 14/16 patients (87.5 %) with a median number of 11 (1-31) energy applications. Ablation was unsuccessful in two patients due to an epicardial location of a right atrial focus (n = 1) and a focus close to the His bundle (n = 1), respectively. Median procedure time was 210 (84-332) min, and median fluoroscopy time was 13.1 (4.5-22.5) min. In pediatric patients with FAT, 3D mapping and catheter ablation provided improved clinical quality of care. Catheter ablation may be considered early in the course of treatment of this tachyarrhythmia in symptomatic patients.

  19. Catheter ablation of pediatric AV nodal reentrant tachycardia: results in small children.

    PubMed

    Krause, Ulrich; Backhoff, David; Klehs, Sophia; Kriebel, Thomas; Paul, Thomas; Schneider, Heike E

    2015-11-01

    AV nodal reentrant tachycardia (AVNRT) is commonly encountered in pediatric patients. Definite treatment can be achieved by catheter ablation. The purpose of the study was to evaluate the efficacy and safety of AVNRT ablation focusing on children with a body weight ≤25 kg. Catheter ablation of AVNRT was attempted in 253 patients. Median age was 12.5 years; median body weight was 48.7 kg. 25 (9.9 %) children had a body weight ≤25 kg. Congenital heart disease was present in 6 patients (2.4 %). Procedural success was achieved in 98 % using radiofrequency, in 100 % using cryoenergy alone, and in 94 % using both energy sources. In patients with a body weight ≤25 kg, success was achieved in 96 %. In patients ≤25 kg, fluoroscopy and procedure duration did not differ from those >25 kg. The rate of major complications was significantly higher in the patients ≤25 kg (12 vs. 2.2 %, p = 0.04). Permanent AV block after RF ablation occurred in 2 patients with congenital heart disease and one infant with a body weight of 8.7 kg. Catheter ablation of AVNRT in children and adolescents was safe and effective. Infants and small children with a body weight ≤25 kg had a higher prevalence of serious complications. This should alert physicians in decision making toward catheter ablation in these patients. In patients with congenital heart disease and different anatomy of the cardiac conduction system, operators must be aware of an increased risk for AV block.

  20. RF Heating of MRI-Assisted Catheter Steering Coils for Interventional MRI.

    PubMed

    Settecase, Fabio; Hetts, Steven W; Martin, Alastair J; Roberts, Timothy P L; Bernhardt, Anthony F; Evans, Lee; Malba, Vincent; Saeed, Maythem; Arenson, Ronald L; Kucharzyk, Walter; Wilson, Mark W

    2011-03-01

    The aim of this study was too assess magnetic resonance imaging (MRI) radiofrequency (RF)-related heating of conductive wire coils used in magnetically steerable endovascular catheters. A three-axis microcoil was fabricated onto a 1.8Fr catheter tip. In vitro testing was performed on a 1.5-T MRI system using an agarose gel-filled vessel phantom, a transmit-receive body RF coil, a steady-state free precession pulse sequence, and a fluoroptic thermometry system. Temperature was measured without simulated blood flow at varying distances from the magnet isocenter and at varying flip angles. Additional experiments were performed with laser-lithographed single-axis microcoil-tipped microcatheters in air and in a saline bath with varied grounding of the microcoil wires. Preliminary in vivo evaluation of RF heating was performed in pigs at 1.5 T with coil-tipped catheters in various positions in the common carotid arteries with steady-state free precession pulse sequence on and off and under physiologic-flow and zero-flow conditions. In tissue-mimicking agarose gel, RF heating resulted in a maximal temperature increase of 0.35°C after 15 minutes of imaging, 15 cm from the magnet isocenter. For a single-axis microcoil, maximal temperature increases were 0.73°C to 1.91°C in air and 0.45°C to 0.55°C in saline. In vivo, delayed contrast-enhanced MRI revealed no evidence of vascular injury, and histopathologic sections from the common carotid arteries confirmed the lack of vascular damage. Microcatheter tip microcoils for endovascular catheter steering in MRI experience minimal RF heating under the conditions tested. These data provide the basis for further in vivo testing of this promising technology for endovascular interventional MRI. Copyright © 2011 AUR. Published by Elsevier Inc. All rights reserved.

  1. Nonfluoroscopic Imaging as Guidance for Radiofrequency Ablation of Atrioventricular Nodal Reentrant Tachycardia after Mustard Repair

    PubMed Central

    Nguyen, Dinh Q.; Sobczak, Henrik; Brandts, Bodo

    2017-01-01

    Most tachycardias in the pulmonary venous atrium are inaccessible by direct means and require either a retrograde approach or a transseptal approach for ablation. We present a case in which successful radiofrequency ablation of common atrioventricular nodal reentrant tachycardia was accomplished via a retrograde transaortic approach guided by nonfluoroscopic mapping with use of the NavX™ mapping system. The patient was a 49-year-old woman who at the age of 4 years had undergone Mustard repair for complete dextrotransposition of the great arteries. Three-dimensional reconstructions of the ascending aorta, right ventricle, systemic venous atrium, left ventricle, and superior vena cava–inferior vena cava baffle complex were created, and the left-sided His bundle was marked. After a failed attempt at ablation from the systemic venous side, we eliminated the atrioventricular nodal reentrant tachycardia by ablation from the pulmonary venous side. This case is, to our knowledge, the first report of successful radiofrequency ablation of common atrioventricular nodal reentrant tachycardia after Mustard repair for this congenital cardiac malformation in which ablation was guided by 3-dimensional nonfluoroscopic imaging. This imaging technique enabled accurate anatomic location of the ablation catheters in relation to the His bundle marked from the systemic venous side. PMID:28265215

  2. Assessment of radiofrequency self-heating around a metallic wire with MR T1-based thermometry.

    PubMed

    Detti, V; Grenier, D; Perrin, E; Beuf, O

    2011-08-01

    Heat produced by a magnetic resonance (MR) imaging sequence in the vicinity of a conductive wire (pacemaker, electrodes, or catheter), is a subject of interest for the assessment of patient safety during imaging. For this purpose, the measurement of temperature rises during an MR imaging sequence using MR T1-based thermometry provides several advantages, mainly in its ability to retrieve in situ real-time thermal maps. Recent studies investigated the heat produced by an independent radiofrequency pulse, assessing MR imaging sequence heating using a specific MR thermometry sequence. This study focuses on self-heating for which the radiofrequency pulses used for measuring temperature create the heat. An experimental design was set up to evaluate T1-based thermometry self-heating using a coupled/decoupled wire and to compare it with a reference temperature gathered by an optical fiber device. For the tested experimental set up, T1-based thermometry is in fairly good agreement with optical fiber reference temperature.

  3. Unguarded tricuspid orifice with pulmonary atresia: successful radiofrequency ablation of an accessory pathway in an infant

    PubMed Central

    Magee, A.; Rosenthal, E.; Bostock, J.; Gill, J.

    1998-01-01

    A male infant with the rare lesion of unguarded tricuspid orifice in the setting of pulmonary valve atresia, intact ventricular septum, and a hypoplastic right ventricle is described. The patient presented with cyanosis at 1 day old; transcutaneous oxygen saturations were between 20% and 30% in room air, and 60% in 100% inspired oxygen. Pre-excitation was found incidentally on the ECG and the potential for rapid antegrade conduction of atrial tachyarrhythmias, after eventual extended palliation with the Fontan procedure, was demonstrated at electrophysiological study. By 11 months old the patient was becoming increasingly cyanosed and interim palliation with a bidirectional cavopulmonary shunt was proposed. Successful radiofrequency ablation of the accessory pathway was performed before bidirectional cavopulmonary shunt, which would have prevented access to the heart via the superior vena cava. Difficulty with femoral venous access because of previous occlusion of a femoral vein was overcome by the use of 2 F pacing electrodes and a 5 F ablation catheter.

 Keywords: radiofrequency ablation;  accessory pathway;  unguarded tricuspid orifice PMID:9505931

  4. Pulsed radiofrequency for occipital neuralgia.

    PubMed

    Manolitsis, Nicholas; Elahi, Foad

    2014-01-01

    The clinical application of pulsed radiofrequency (PRF) by interventional pain physicians for a variety of chronic pain syndromes, including occipital neuralgia, is growing. As a minimally invasive percutaneous technique with none to minimal neurodestruction and a favorable side effect profile, use of PRF as an interventional neuromodulatory chronic pain treatment is appealing. Occipital neuralgia, also known as Arnold's neuralgia, is defined by the International Headache Society as a paroxysmal, shooting or stabbing pain in the greater, lesser, and/or third occipital nerve distributions. Pain intensity is often severe and debilitating, with an associated negative impact upon quality of life and function. Most cases of occipital neuralgia are idiopathic, with no clearly identifiable structural etiology. Treatment of occipital neuralgia poses inherent challenges as no criterion standard exists. Initially, conservative treatment options such as physical therapy and pharmacotherapy are routinely trialed. When occipital neuralgia is refractory to conservative measures, a number of interventional treatment options exist, including: local occipital nerve anesthetic and corticosteroid infiltration, botulinum toxin A injection, occipital nerve subcutaneous neurostimulation, and occipital nerve PRF. Of these, PRF has garnered significant interest as a potentially superior, safe, non-invasive treatment with long-term efficacy. The objective of this article is to provide a concise review of occipital neuralgia; and a concise, yet thorough, evidence-based review of the current literature concerning the use of PRF for occipital neuralgia. Review of published medical literature up through April 2013. The Center for Pain Medicine and Regional Anesthesia, the University of Iowa Hospitals and Clinics. A total of 3 clinical studies and one case report investigating the use of PRF for knee occipital neuralgia have been published worldwide. Statistically significant improvements in

  5. Is Cryoballoon Ablation Preferable to Radiofrequency Ablation for Treatment of Atrial Fibrillation by Pulmonary Vein Isolation? A Meta-Analysis

    PubMed Central

    Xu, Junxia; Huang, Yingqun; Cai, Hongbin; Qi, Yue; Jia, Nan; Shen, Weifeng; Lin, Jinxiu; Peng, Feng; Niu, Wenquan

    2014-01-01

    Objective Currently radiofrequency and cryoballoon ablations are the two standard ablation systems used for catheter ablation of atrial fibrillation; however, there is no universal consensus on which ablation is the optimal choice. We therefore sought to undertake a meta-analysis with special emphases on comparing the efficacy and safety between cryoballoon and radiofrequency ablations by synthesizing published clinical trials. Methods and Results Articles were identified by searching the MEDLINE and EMBASE databases before September 2013, by reviewing the bibliographies of eligible reports, and by consulting with experts in this field. Data were extracted independently and in duplicate. There were respectively 469 and 635 patients referred for cryoballoon and radiofrequency ablations from 14 qualified clinical trials. Overall analyses indicated that cryoballoon ablation significantly reduced fluoroscopic time and total procedure time by a weighted mean of 14.13 (95% confidence interval [95% CI]: 2.82 to 25.45; P = 0.014) minutes and 29.65 (95% CI: 8.54 to 50.77; P = 0.006) minutes compared with radiofrequency ablation, respectively, whereas ablation time in cryoballoon ablation was nonsignificantly elongated by a weighted mean of 11.66 (95% CI: −10.71 to 34.04; P = 0.307) minutes. Patients referred for cryoballoon ablation had a high yet nonsignificant success rate of catheter ablation compared with cryoballoon ablation (odds ratio; 95% CI; P: 1.34; 0.53 to 3.36; 0.538), and cryoballoon ablation was also found to be associated with the relatively low risk of having recurrent atrial fibrillation (0.75; 0.3 to 1.88; 0.538) and major complications (0.46; 0.11 to 1.83; 0.269). There was strong evidence of heterogeneity and low probability of publication bias. Conclusion Our findings demonstrate greater improvement in fluoroscopic time and total procedure duration for atrial fibrillation patients referred for cryoballoon ablation than those for

  6. The efficacy of noble metal alloy urinary catheters in reducing catheter-associated urinary tract infection

    PubMed Central

    Aljohi, Alanood Ahmed; Hassan, Hanan Elkefafy; Gupta, Rakesh Kumar

    2016-01-01

    Background: Catheter-associated urinary tract infection (CAUTI) is the most common device-related healthcare-acquired infection. CAUTI can be severe and lead to bacteremia, significant morbidity, prolonged hospital stay, and high antibiotic consumption. Patients and Methods: In this study, we evaluated the CAUTI-reducing efficacy of noble metal alloy catheters in sixty patients (thirty per group) in the Intensive Care Unit (ICU) at the King Fahad Hospital in Saudi Arabia. The study was a single-blinded, randomized, single-centered, prospective investigation that included patients using urinary catheters for 3 days. Results: A 90% relative risk reduction in the rate of CAUTI was observed with the noble metal alloy catheter compared to the standard catheter (10 vs. 1 cases, P = 0.006). When considering both catheter-associated asymptomatic bacteriuria and CAUTI, the relative risk reduction was 83% (12 vs. 2 cases, P = 0.005). In addition to CAUTI, the risk of acquiring secondary bacteremia was lower (100%) for the patients using noble metal alloy catheters (3 cases in the standard group vs. 0 case in the noble metal alloy catheter group, P = 0.24). No adverse events related to any of the used catheters were recorded. Conclusion: Results from this study revealed that noble metal alloy catheters are safe to use and significantly reduce CAUTI rate in ICU patients after 3 days of use. PMID:28057985

  7. Carbon nanotube facilitation of myocardial ablation with radiofrequency energy.

    PubMed

    Nguyen, Duy T; Barham, Waseem; Zheng, Lijun; Shillinglaw, Benjamin; Tzou, Wendy S; Neltner, Bonnie; Mestroni, Luisa; Bosi, Susanna; Ballerini, Laura; Prato, Maurizio; Sauer, William H

    2014-12-01

    The use of carbon nanotubes (CNTs) in oncology has been proposed for the purpose of sensitizing tumors to radiofrequency (RF) ablation. We hypothesize that myocardial tissue infiltrated with CNTs will improve thermal conductivity of RF heating and lead to altered ablation lesion characteristics. An ex vivo model consisting of viable bovine myocardium, a circulating saline bath at 37 °C, a submersible load cell, and a deflectable sheath was assembled. A 4-mm nonirrigated ablation catheter was positioned with 10 gm of force over bovine myocardium infiltrated with CNTs, 0.9% saline, or sham injections. A series of ablation lesions were delivered at 20 and 50 W, and lesion volumes were acquired by analyzing tissue sections with a digital micrometer. Tissue temperature analyses at 3 and 5 mm depths were also performed. Myocardial tissue treated with CNTs resulted in significantly larger lesions at both low and high power settings. The electrical impedance was increased in CNT treated tissue with a greater impedance change observed in the CNT infiltrated myocardium. The thermal conductivity of heat generated by application of RF in the tissue was altered by the presence of CNTs, resulting in higher temperatures at 3 and 5 mm depths for both 20 and 50 W. Myocardial tissue treated with CNTs resulted in significantly larger lesions at both low and high power settings. The electrical and thermal conductivity of heat generated by application of RF in myocardial tissue was altered by the presence of CNTs. Further research is needed to assess the in vivo applicability for this concept of facilitated ablation with CNTs. © 2014 Wiley Periodicals, Inc.

  8. Radiofrequency balloon angioplasty. Rationale and proof of principle

    SciTech Connect

    Becker, G.J.; Lee, B.I.; Waller, B.F.; Barry, K.J.; Kaplan, J.; Connolly, R.; Dreesen, R.G.; Nardella, P.

    1988-11-01

    Post-angioplasty restenosis (PARS) in atherosclerotic lesions of medium and small arteries occurs in about one-third of cases in the first year following percutaneous transluminal angioplasty (PTA) (early PARS). PARS includes acute spasm, dissection with reclosure, elastic recoil, fibrocellular proliferative response, and progressive atheromatous disease. Fibrocellular proliferation (possibly initiated by platelet derived growth factor) is felt to be culpable in many cases of early PARS (months). Pharmacologic regimens, stents, and thermal welding of the intimal-medial cracks of PTA are among the interventions being developed to deal with PARS. Radiofrequency (RF) current as a source of thermal energy may be useful in combination with balloon angioplasty to reduce PARS. Ideally, this combination would (1) weld intimal-medial cracks of PTA; (2) mold plaque and normal vessel to increase lumen diameters without creating intimal-medial cracks; and (3) destroy medial smooth muscle cells and multipotential cells (cellular substrate of PARS). Canine in vivo studies have established the feasibility of RF-mediated vascular tissue welding. Human aortic specimens (N = 28) were manually dissected into intima-media and media-adventitia layers. Bipolar RF energy (650 KHz, total 300 J) and mechanical pressure (1 atm) (experimental group, N = 24) or mechanical pressure alone (control group, N = 4) were applied to the reapposed specimen layers in a special chamber. The chamber was modified with a bipolar electrode designed to reproduce that planned for an RF balloon angioplasty catheter. Welding was demonstrated in normal and atherosclerotic treated specimens (23/24 or 96%) but not controls (0/4).

  9. Managing turbinate hypertrophy: coblation vs. radiofrequency treatment.

    PubMed

    Passali, D; Loglisci, M; Politi, L; Passali, G C; Kern, E

    2016-06-01

    The role of inferior turbinate hypertrophy in the reduction of nasal airflow is well established. Although chronic nasal obstruction is not life- threatening, it significantly impairs patients' quality of life, affecting many aspects of daily activities; therefore, patients seek medical intervention. 40 patients were selected (27 males and 13 females) between 27 and 64 years of age with a symptom of nasal obstruction. The patients were divided in two groups: Group 1: coblation, 25 patients (18 males and 7 females); Group 2: radiofrequency, 15 patients (7 males and 6 females). These 40 patients were followed for 3 years. Patients were analyzed using both subjective and objective methods. The visual analog scale (VAS) subjective data and objective data including both active anterior rhinomanometry and acoustic rhinometry were recorded and analyzed. Data were collected pre-operatively and at 1 and 3 years post-operatively. According to our data, both coblation and radiofrequency turbinate reduction benefit patients with good results. The complications, found during the follow-up, are limited to minimal bleeding and crusting. Coblation and radiofrequency were significantly less painful than others procedures during the early post-operative period. In our study, both coblation and radiofrequency provide an improvement in nasal airflow with a reduction in nasal obstructive symptoms in the short term, but their efficacy tended to decrease within 3 years.

  10. Radiofrequency identification technology: protecting the drug supply.

    PubMed

    2005-01-01

    The FDA has stepped up its efforts to improve the safety and security of the nation's drug supply by encouraging the use of a state-of-the-art technology that tags product packaging electronically. The technology, called radiofrequency identification, or RFID, allows manufacturers and distributors to more precisely track drug products through the supply chain.

  11. Percutaneous Radiofrequency Ablation of Nodal Metastases

    SciTech Connect

    Gervais, Debra A.; Arellano, Ronald S.; Mueller, Peter R.

    2002-12-15

    We report our experience with percutaneous image-guided radiofrequency (RF) ablation to treat isolated nodal metastases. Four patients underwent image-guided percutaneous RF ablation of metastatic disease involving retrocrural nodes,retroperitoneal nodes, or pelvic nodes. Coagulation necrosis was achieved in all cases.

  12. Principles of tunneled cuffed catheter placement.

    PubMed

    Heberlein, Wolf

    2011-12-01

    Tunneled cuffed catheters provide reliable and instant long-term intravenous access for a large variety of therapeutic purposes, including chemotherapy, parenteral nutrition, and apheresis. The most frequent application is for patients with renal failure as an access device for hemodialysis. In this capacity, the rate of catheter use has remained stable in the United States, despite the promotion of arteriovenous fistulas and arteriovenous grafts. The latter 2 procedures achieve superior longevity and much higher cost-efficiency. Tunneled catheters, however, serve as bridging devices during maturation of newly placed arteriovenous fistulas or as the final option in patients in whom fistulas and grafts have failed. High-quality vascular access is a hallmark of interventional radiology, and its significance for patient care and for our specialty cannot be overestimated. Familiarity with basic concepts of the device and procedural techniques are crucial to achieve successful long-term venous access. The following article demonstrates key concepts of tunneled venous catheter placement by means of dialysis, inasmuch as dialysis catheters represent the most commonly placed tunneled central venous catheters. The principles of placement and techniques utilized, however, are applicable to devices that are used for chemotherapy or parenteral nutrition, such as the Hickman, Broviac, Groshong, or tunneled peripherally inserted central catheters.

  13. [Multifunctional testing of PTCA balloon catheters].

    PubMed

    Kraft, M; Schmitz, H; Schulte, R; Boenick, U

    2000-06-01

    New in vitro measuring methods for balloon catheters used for percutaneous transluminal coronary angioplasty (PTCA) and their verification in a complex test device are presented. This system can mimic all relevant application situations. The central element of the test device is a coronary vessel model matching the physiological situation in terms of geometrical structure and frictional properties. Reactive force sensors are used to measure the application-relevant forces exerted by the catheter on the model vessel walls and accessories, such as guide wire and guiding catheter. To generate a kink-free advancement of the catheter and permit measurement of the active forces, an alternating drive unit has been specially developed. The testing and application of the newly developed methods revealed statistically significant differences between various types of catheter. The test device closes a gap between complex but subjective clinical tests, and individual objective, but application-removed in vitro test setups for PTCA catheters. While the initial prototype had shortcomings with regard to the reproducibility of measurements, successor systems developed for industrial use are now in production. The properties of these measuring systems developed for the benefit of manufacturer and reprocessor of PTCA catheters are discussed.

  14. Catheter-related complications of cancer therapy.

    PubMed

    Greene, J N

    1996-06-01

    Although the management of CVC-related infection appears complex and at times the literature seems to be contradictory, simple guidelines can direct the clinician in a stepwise fashion. Knowledge of the pathogenesis of each organism and the immune status of the host is crucial to decide whether catheter removal or retention is indicated. For example, in general, GNB bacteremia does not immediately prompt catheter removal in a neutropenic patient but does in a nonneutropenic host because of the gastrointestinal source of the former and a primary catheter source in the latter. In summary, as more CVCs are inserted in patients undergoing chemotherapeutic, antimicrobial, transfusional, and nutritional supportive care, novel approaches to prevention and treatment of the associated infectious complications inherent with such devices are needed. A multifaceted approach from impregnated catheters to local catheter-site antisepsis was reviewed. We may find, however, that as simple handwashing between patients is crucial to infection control, so too is a trained catheter-care team using total barrier precautions and ensuring proper local catheter maintenance critical to preventing CVC-related infections.

  15. The pulmonary artery catheter: in medio virtus.

    PubMed

    Vincent, Jean-Louis; Pinsky, Michael R; Sprung, Charles L; Levy, Mitchell; Marini, John J; Payen, Didier; Rhodes, Andrew; Takala, Jukka

    2008-11-01

    To clarify the role of the pulmonary artery catheter in the intensive care unit. Recent and relevant literature from MEDLINE and authors' personal databases. Studies on pulmonary artery catheter use and use of other monitoring devices in critically ill patients. Based largely on clinical experience and assessment of the relevant published literature and in response to recent articles attacking the pulmonary artery catheter, we propose that the pulmonary artery catheter is still a valuable tool for the hemodynamic monitoring of patients with complex disease processes in whom the information obtained from the pulmonary artery catheter may influence management. We suggest that there is a need to revisit the basics of hemodynamic management and reassess the way in which the pulmonary artery catheter is used, applying three key principles: correct measurement, correct data interpretation, and correct application. The pulmonary artery catheter is still a valuable tool for hemodynamic monitoring when used in selected patients and by physicians adequately trained to correctly interpret and apply the data provided.

  16. Silicon sensors for catheters and guide wires

    NASA Astrophysics Data System (ADS)

    Goosen, Hans F.

    2001-11-01

    One area that can make use of the miniature size of present day micro electromechanical systems (MEMS) is that of the medical field of minimally invasive interventions. These procedures, used for both diagnosis and treatment, use catheters that are advanced through the blood vessels deep into the body, without the need for surgery. However, once inside the body, the doctor performing the procedure is completely reliant on the information the catheter(s) can provide in addition to the projection imaging of a fluoroscope. A good range of sensors for catheters is required for a proper diagnosis. To this end, miniature sensors are being developed to be fitted to catheters and guide wires. As the accurate positioning of these instruments is problematic, it is necessary to combine several sensors on the same guide wire or catheter to measure several parameters in the same location. This however, brings many special problems to the design of the sensors, such as small size, low power consumption, bio-compatibility of materials, robust design for patient safety, a limited number of connections, packaging, etc. This paper will go into both the advantages and design problems of micromachined sensors and actuators in catheters and guide wires. As an example, a multi parameter blood sensor, measuring flow velocity, pressure and oxygen saturation, will be discussed.

  17. Skeleton-based active catheter navigation.

    PubMed

    Fu, Yili; Liu, Hao; Wang, Shuguo; Deng, Wei; Li, Xianling; Liang, Zhaoguang

    2009-06-01

    The emergence of the active catheter has prompted the development of catheterization in minimally invasive surgery. However, it is still operated using only the physician's vision; information supplied by the guiding image and tracking sensors has not been fully utilized. In order to supply the active catheter with more useful information for automatic navigation, we extract the skeleton of blood vessels by means of an improved distance transform method, and then present the crucial geometric information determining navigation. With the help of tracking sensors' position and pose information, two operations, advancement in the proximal end and direction selection in the distal end, are alternately implemented to insert the active catheter into a target blood vessel. The skeleton of the aortic arch reconstructed from slice images is extracted fast and automatically. A navigation path is generated on the skeleton by manually selecting the start and target points, and smoothed with the cubic cardinal spline curve. Crucial geometric information determining navigation is presented, as well as requirements for the catheter entering the target blood vessel. Using a shape memory alloy active catheter integrated with magnetic sensors, an experiment is carried out in a vascular model, in which the catheter is successfully inserted from the ascending aorta, via the aortic arch, into the brachiocephalic trunk. The navigation strategy proposed in this paper is feasible and has the advantage of increasing the automation of catheterization, enhancing the manoeuvrability of the active catheter and providing the guiding image with desirable interactivity.

  18. Decreasing catheter colonization through the use of an antiseptic-impregnated catheter: a continuous quality improvement project.

    PubMed

    Collin, G R

    1999-06-01

    To evaluate the use of an antiseptic-impregnated (chlorhexidine and silver sulfadiazine) catheter for the prevention of catheter colonization and catheter-related bloodstream infection (CR-BSI). Then, based on these findings, to implement changes in hospital policy and to assess their effect on a hospital service. Prospective, randomized, controlled (phase I); prospective, concurrent data collection (phase II). Tertiary referral hospital with level 1 trauma center. Patients > 12 years of age with central venous catheters placed while they were in the emergency room, neurotrauma ICU, or medical/surgical ICU from May through December, 1995 (phase I). All patients > 12 years of age on the trauma service admitted from November 16, 1996, through November 15, 1997 (phase II). Randomization table determined whether the patient would receive an antiseptic-impregnated catheter (AIC) or nonimpregnated catheter (NIC) (phase I). All removed or exchanged catheters were sent for semiquantitative culture. In phase II, only AICs were used; "length of time" and "fever" were discouraged as reasons for catheter exchange or removal; and only the tip was sent for culture. In phase I, there were 139 catheters placed in 60 patients in the NIC group and 98 catheters placed in 55 patients in the AIC group. Two catheters (2.0/100 catheters) in the AIC group were found to be colonized, compared with 25 (18.0/100 catheters) in the NIC group (p = 0.001). The catheter colonization rates were 2.27/1,000 catheter days (AIC) and 24.68/1,000 catheter days (NIC) (p < 0.001), while the CR-BSI rates were 1.14/1,000 catheter days (AIC) and 3.9.5/1,000 catheter days (NIC) (p = 0.31). The reason for each catheter removal/exchange was noted, and only "positive blood culture" was statistically significant overall. The tip segment was found to be positive more often than the intracutaneous segment. In phase II, there were 213 AICs placed in 101 patients. The colonization rate was 3.8/100 catheters (4

  19. ATLS: Catheter and tube placement

    NASA Technical Reports Server (NTRS)

    Gosbee, John; Krupa, Debra T.; Pepper, L.; Orsak, Debra

    1991-01-01

    The specific objectives of this experiment are: to evaluate the rack mounted equipment and medical supplies necessary for medical procedures; to evaluate the attachments, mounting points, and inner drawer assemblies for the medical supplies; and to evaluate the procedures for performing medical scenarios. The resources available in the HMF miniracks to accomplish medical scenarios and/or procedures include: medical equipment mounted in the racks; a patch panel with places to attach tubing and catheters; self contained drawers full of critical care medical supplies; and an ALS 'backpack' for deploying supplies. The attachment lines, tubing and associated medical supplies will be deployed and used with the equipment and a patient mannequin. Data collection is provided by direct observations by the inflight experimenters, and analysis of still and video photography.

  20. Catheters for optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Atif, M.; Ullah, H.; Hamza, M. Y.; Ikram, M.

    2011-09-01

    The objective of this review article is to overview technology, clinical evidence, and future applications to date optical coherence tomography (OCT) probes to yield the diagnostic purpose. We have reviewed the designing, construction and working of different categories of OCT probes developed for optical diagnostics having a potential for non invasive and improved detection of different types of cancer as well as other neoplasm. Rotational and balloon catheters, imaging needles and hand-held, linear scanning, multichannel, micro electro mechanical systems (MEMS) technology based, dynamic focusing, forward view imaging, and common path interferometer based probes have been discussed in details. The fiber probes have shown excellent performance for two dimensional and three dimensional higher resolution, cross-sectional imaging of interior and exterior body tissues that can be compared with histopathology to provide the information about the angiogenesis and other lesions in the tissue. The MEMS-technology based probes are found to be more suitable for three dimensional morphological imaging.

  1. Radiofrequency and Cryo-ablation Effect on Transvenous Pacing and Defibrillatory Lead Integrity: An in vitro study

    PubMed Central

    Darrat, Yousef H; Agarwal, Anuj; Morales, Gustavo X; Thompson, Joseph; Abdel-Latif, Ahmed; Waespe, Kelly; Biase, Luigi Di; Natale, Andrea; Patwardan, Abhijit; Elayi, Claude-Samy

    2017-01-01

    Introduction Medical societies and cardiac implantable electronic devices (CIED) manufacturers recommend avoiding close or direct contact between the body of transvenous leads and ablation catheters used to treat cardiac arrhythmias. These recommendations are made despite the lack of clinical studies. However, the target myocardium for successful ablation can be contiguous to CIED leads. Methods and Results We examine in vitro the effects of direct application of radiofrequency (RF) and cryo-ablation energy on the integrity and functionality of CIED leads (excluding the pacing electrodes and defibrillation coils). A saline bath was created to mimic the body milieu. CIED leads, including all commercially available lead insulation materials, were connected to a CIED pulse generator and placed in direct contact with ablation catheter in the tissue bath. RF and cryo-ablation energy were delivered under various conditions, including maximal ablation power, temperature and impedance via the RF generator. CIED lead functionality, reflective of conductor integrity, was evaluated through lead impedance monitoring during ablation. CIED leads were then visually inspected, and examined with optic and electron microscopy as per protocol. A total of 42 leads were studied. All leads showed absence of insulation damage at the site of ablation visually and with microscopy. Lead functionality was also preserved in all leads. Conclusion Catheter ablation in contact with CIED leads using radiofrequency or cryo-ablation in vitro did not affect lead body integrity and function despite aggressive ablation settings. It may be reasonable to perform ablation in contact with the body of CIED leads when clinically necessary. PMID:27138905

  2. 21 CFR 870.1210 - Continuous flush catheter.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1210 Continuous flush catheter. (a) Identification. A continuous flush catheter is an attachment to a catheter-transducer system... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Continuous flush catheter. 870.1210 Section...

  3. 21 CFR 870.1210 - Continuous flush catheter.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1210 Continuous flush catheter. (a) Identification. A continuous flush catheter is an attachment to a catheter-transducer system... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Continuous flush catheter. 870.1210 Section...

  4. 21 CFR 870.1210 - Continuous flush catheter.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1210 Continuous flush catheter. (a) Identification. A continuous flush catheter is an attachment to a catheter-transducer system... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Continuous flush catheter. 870.1210 Section...

  5. A novel catheter design for laser photocoagulation of the myocardium to ablate ventricular tachycardia.

    PubMed

    Wagshall, Alan; Abela, George S; Maheshwari, Alok; Gupta, Anoop; Bowden, Russell; Huang, S K Stephen

    2002-08-01

    Nd:YAG laser energy has been proposed as an alternative to radiofrequency energy for ablation of ventricular tachycardia (VT) associated with coronary artery disease (CAD) in an effort to increase lesion size and success rates. However, issues of catheter design to maintain flexibility and ensure adequate tissue contact have hindered development of laser catheters. We developed and tested a prototype 8 Fr. steerable catheter with a flexible and extendible tip (designed to ensure tissue contact and efficient ventricular mapping), which projects the laser beam through a side port containing a lens-tipped optical fiber that rests against the endocardial surface. The catheter has a channel for simultaneous saline irrigation to displace the interceding blood and discharge a laser beam between two electrodes for bipolar mapping and a thermocouple for temperature monitoring. The catheter was tested on bench top using the epicardial surface of freshly slaughtered bovine hearts and in vivo using six anaesthetized closed-chest sheep. In vitro experiments demonstrated that lesion size increased linearly with applied power up to 40 watts. When compared to radio frequency, laser energy penetrated more deeply into the myocardium. In the in vivo studies, using increasing powers of up to 40 watts for application times of 60 to 120 seconds created circular or elliptical lesions with surface dimensions up to 12 mm x 12 mm and depth of 9 mm (full LV wall thickness with a mean lesion diameter of 9.9 +/- 5.2 mm and depth 5.8 +/- 3.2 mm). Most lesions, 16 total in both right and left ventricular walls were transmural or near transmural in thickness. Lesions demonstrated coagulation necrosis with smooth well-demarcated borders. No animal suffered cardiac perforation, hypotension, hemopericardium, damage to cardiac valves, or cavitation effect from any of the ablations. Runs of VT were seen during energy application at the highest laser outputs in two animals. In conclusion, this catheter

  6. Ocular effects of radiofrequency energy.

    PubMed

    Elder, J A

    2003-01-01

    Radiofrequency (RF) energy has been reported to cause a variety of ocular effects, primarily cataracts but also effects on the retina, cornea, and other ocular systems. Cataracts have been observed in experimental animals when one eye was exposed to a localized, very high RF field and the other eye was the unexposed control. The results show that 2450 MHz exposures for >or=30 min at power densities causing extremely high dose rates (>or=150 W/kg) and temperatures (>or=41 degrees C) in or near the lens caused cataracts in the rabbit eye. However, cataracts were not observed in the monkey eye exposed to similar exposure conditions, reflecting the different patterns of energy absorption (SAR, specific absorption rate) distribution, due to their different facial structure. Since the monkey head is similar in structure to the human head, the nonhuman primate study showed that the incident power density levels causing cataracts in rabbits and other laboratory animals cannot be directly extrapolated to primates, including human beings. It is reasonable to assume that an SAR that would induce temperatures >or=41 degrees C in or near the lens in the human eye would produce cataracts by the same mechanism (heating) that caused cataracts in the rabbit lens; however, such an exposure would greatly exceed the currently allowable limits for human exposure and would be expected to cause unacceptable effects in other parts of the eye and face. Other ocular effects including corneal lesions, retinal effects, and changes in vascular permeability, have been observed after localized exposure of the eye of laboratory animals to both continuous wave (CW) and pulsed wave (PW) exposures, but the inconsistencies in these results, the failure to independently confirm corneal lesions after CW exposure, the failure to independently confirm retinal effects after PW exposure, and the absence of functional changes in vision are reasons why these ocular effects are not useful in defining an

  7. Use of articulated catheters in the treatment of biliary strictures

    SciTech Connect

    Shlansky-Goldberg, Richard D.; Soulen, Michael C.; Haskal, Ziv J.; Cope, Constantin

    1997-05-15

    We have used a single articulated catheter to obviate the need for multiple catheters in patients with complex biliary strictures or strictures associated with small or immature tracts. Two- and three-arm articulated drains (8-14 Fr) made from segments of biliary catheters were placed in 16 patients. Nine were placed transhepatically, 6 transperitoneally through existing T-tube tracts, and 1 through a cystic duct fistula. Six malignant and 10 benign strictures were stented with various catheter configurations through a single tract. Fifteen patients had two catheter components with one articulation and 1 patient had three catheter components with two articulations. The average duration of catheter drainage was 7.0 {+-} 4.2 months. Routine catheter exchanges were performed; two spontaneous occlusions occurred. In patients where internal stenting may be difficult or undesirable, articulated catheters allow satisfactory external and internal drainage of complex benign and malignant strictures through a single tract, avoiding the need for multiple transhepatic catheters.

  8. Early removal of urinary catheters in patients with thoracic epidural catheters.

    PubMed

    Tripepi-Bova, Kathleen A; Sun, Zhiyuan; Mason, David; Albert, Nancy M

    2013-01-01

    The purpose of this study was to determine whether early removal of urinary catheters in patients with thoracic epidurals resulted in urinary retention (>500 mL by bladder scanner). Patients were given up to 8 hours to void before further intervention. Of 61 patients, only 4 (6.6%) required urinary catheter reinsertion due to urinary retention. Early removal of urinary catheters after thoracic surgery in patients with thoracic epidurals was safe, with minimal urinary retention.

  9. Randomized comparison of popliteal-sciatic perineural catheter tip migration and dislocation in a cadaver model using two catheter designs

    PubMed Central

    Steffel, Lauren; Howard, Steven K.; Borg, Lindsay; Leng, Jody C.; Kim, T. Edward

    2017-01-01

    Background New catheter-over-needle (CON) technology for continuous peripheral nerve blockade has emerged, but its effect on the risk of perineural catheter tip dislocation is unknown. Less flexible catheters may be more likely to migrate away from the nerve with simulated patient movement. In the present study, we evaluated catheter tip migration between CON catheters and traditional catheter-through-needle (CTN) catheters during ultrasound-guided short-axis in-plane (SAX-IP) insertion. Methods We evaluated the migration of popliteal-sciatic catheters in a prone, unembalmed male cadaver. Thirty catheter placement trials were divided randomly into two groups based on the catheter type: CON or CTN. A single anesthesiology resident placed the catheters by SAX-IP insertion, and the catheters were then examined by ultrasound before and after ipsilateral knee range of motion (ROM) exercises (0°–130° flexion). A blinded expert regional anesthesiologist performed caliper measurements on the ultrasound images before and after the ROM exercises. The primary outcome was the change in distance from the catheter tip to the center of the nerve (cm) between before and after the ROM exercises. Results The change in the tip-to-nerve distance (median [10th–90th percentile]) was 0.06 (−0.16 to 0.23) cm for the CTN catheter and 0.00 (−0.12 to 0.69) for the CON catheter (P = 0.663). However, there was a statistically significant increase in dislocation out of the nerve compartment for the CON catheter (4/15; 0/15 for CTN) (P = 0.043). Conclusions Although the use of different catheter designs had no effect on the change in the measured migration distance of popliteal-sciatic catheters, 27% of the CON catheters were dislocated out of the nerve compartment. These results may influence the choice of catheter design when using SAX-IP perineural catheter insertion. PMID:28184270

  10. Task-Space Motion Planning of MRI-Actuated Catheters for Catheter Ablation of Atrial Fibrillation.

    PubMed

    Greigarn, Tipakorn; Cavuşoğlu, M Cenk

    2014-09-01

    This paper presents a motion planning algorithm for Magnetic Resonance Imaging (MRI) actuated catheters for catheter ablation of atrial fibrillation. The MRI-actuated catheters is a new robotic catheter concept which utilizes MRI for remote steering and guidance. Magnetic moments generated by a set of coils wound near the tip are used to steer the catheter under MRI scanner magnetic field. The catheter during an ablation procedure is modeled as a constrained robotic manipulator with flexible joints, and the proposed motion-planning algorithm calculates a sequence of magnetic moments based on the manipulator model to move the tip of the catheter along a predefined trajectory on the surface of the left atrium. The difficulties in motion planning of the catheter are due to kinematic redundancy and underactuation. The proposed motion planning algorithm overcomes the challenges by operating in the task space instead of the configuration space. The catheter is then regulated around this nominal trajectory using feedback control to reduce the effect of uncertainties.

  11. Task-Space Motion Planning of MRI-Actuated Catheters for Catheter Ablation of Atrial Fibrillation

    PubMed Central

    Greigarn, Tipakorn; Çavuşoğlu, M. Cenk

    2014-01-01

    This paper presents a motion planning algorithm for Magnetic Resonance Imaging (MRI) actuated catheters for catheter ablation of atrial fibrillation. The MRI-actuated catheters is a new robotic catheter concept which utilizes MRI for remote steering and guidance. Magnetic moments generated by a set of coils wound near the tip are used to steer the catheter under MRI scanner magnetic field. The catheter during an ablation procedure is modeled as a constrained robotic manipulator with flexible joints, and the proposed motion-planning algorithm calculates a sequence of magnetic moments based on the manipulator model to move the tip of the catheter along a predefined trajectory on the surface of the left atrium. The difficulties in motion planning of the catheter are due to kinematic redundancy and underactuation. The proposed motion planning algorithm overcomes the challenges by operating in the task space instead of the configuration space. The catheter is then regulated around this nominal trajectory using feedback control to reduce the effect of uncertainties. PMID:25485168

  12. Antimicrobial-impregnated catheters for the prevention of catheter-related bloodstream infections.

    PubMed

    Lorente, Leonardo

    2016-05-04

    Central venous catheters are commonly used in critically ill patients. Such catheterization may entail mechanical and infectious complications. The interest in catheter-related infection lies in the morbidity, mortality and costs that it involved. Numerous contributions have been made in the prevention of catheter-related infection and the current review focuses on the possible current role of antimicrobial impregnated catheters to reduce catheter-related bloodstream infections (CRBSI). There is evidence that the use of chlorhexidine-silver sulfadiazine (CHSS), rifampicin-minocycline, or rifampicin-miconazol impregnated catheters reduce the incidence of CRBSI and costs. In addition, there are some clinical circumstances associated with higher risk of CRBSI, such as the venous catheter access and the presence of tracheostomy. Current guidelines for the prevention of CRBSI recommended the use of a CHSS or rifampicin-minocycline impregnated catheter in patients whose catheter is expected to remain in place > 5 d and if the CRBSI rate has not decreased after implementation of a comprehensive strategy to reduce it.

  13. Prevention of central venous catheter-related infections: what works other than impregnated or coated catheters?

    PubMed

    Mermel, Leonard A

    2007-06-01

    Catheter-related bloodstream infections (CRBSI) are a significant cause of morbidity and excess hospital cost. Data from prospective, randomized trials demonstrate that the risk of these infections can be minimized by simple interventions. Changing the behaviour of healthcare workers who insert and care for intravascular catheters is imperative. Creating a culture of patient safety and assuring easy access to the products necessary to maintain strict asepsis during catheter insertion, dressing changes, and when manipulating catheter hubs, will enhance adherence to optimal practice and will reduce the risk posed to the millions of patients in need of such devices.

  14. Antimicrobial-impregnated catheters for the prevention of catheter-related bloodstream infections

    PubMed Central

    Lorente, Leonardo

    2016-01-01

    Central venous catheters are commonly used in critically ill patients. Such catheterization may entail mechanical and infectious complications. The interest in catheter-related infection lies in the morbidity, mortality and costs that it involved. Numerous contributions have been made in the prevention of catheter-related infection and the current review focuses on the possible current role of antimicrobial impregnated catheters to reduce catheter-related bloodstream infections (CRBSI). There is evidence that the use of chlorhexidine-silver sulfadiazine (CHSS), rifampicin-minocycline, or rifampicin-miconazol impregnated catheters reduce the incidence of CRBSI and costs. In addition, there are some clinical circumstances associated with higher risk of CRBSI, such as the venous catheter access and the presence of tracheostomy. Current guidelines for the prevention of CRBSI recommended the use of a CHSS or rifampicin-minocycline impregnated catheter in patients whose catheter is expected to remain in place > 5 d and if the CRBSI rate has not decreased after implementation of a comprehensive strategy to reduce it. PMID:27152256

  15. Management and visualization of a kinked epidural catheter

    PubMed Central

    Aslanidis, T; Fileli, A; Pyrgos, P

    2010-01-01

    A lumbar epidural catheter inserted in a 29-year-old woman for labor analgesia. The catheter failed to provide adequate analgesia. Moreover, after labor, it proved difficult to be removed. After computer tomography (CT) and magnetic resonance impedance (MRI) examination the course of the catheter was visible, the entrapped catheter was dislodged intact, revealing a kinking near its distal tip. Kinking of an epidural catheter leading to entrapment is an unusual complication of epidural catheterization. PMID:21311644

  16. Impact of cavotricuspid isthmus morphology in CRYO versus radiofrequency ablation of typical atrial flutter.

    PubMed

    Saygi, Serkan; Bastani, Hamid; Drca, Nikola; Insulander, Per; Wredlert, Christer; Schwieler, Jonas; Jensen-Urstad, Mats

    2017-04-01

    Cryoablation (CRYO) is an alternative to radiofrequency (RF) for catheter ablation of cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL). We aimed to study whether different CTI morphologies had different impacts on procedural success for CRYO and RF. This study randomized 153 patients with CTI-dependent AFL (median age 65 years; range 34-82) to RF or CRYO (78 CRYO; 75 RF). Biplane angiography (RAO 30° and LAO 60°) was done before the ablation procedure and isthmuses were classified as straight (n = 81), concave (n = 43) or pouch-like (n = 29). RF was performed with a 3.5-mm open-irrigated tip catheter and CRYO was performed with a 9 F, 8-mm tip catheter. The ablation endpoint was bidirectional block of CTI. Acute procedural success was achieved in 70/75 patients in the RF group and in 72/78 patients in the CRYO group. With regard to CRYO or RF, acute procedural success rates were similar between the three isthmus types: straight: CRYO (92%) and RF (96%); concave: CRYO (92%) and RF (94%); and pouch-like: CRYO (94%) and RF (85%). There were no significant differences regarding success rate between the different morphologies in the CRYO or the RF group. The CTI was longer in patients with acute failure compared to the patients with acute success (38 ± 7 mm versus 33 ± 6 mm, p = 0.045). The CTI morphology did not influence the acute success rate for either the CRYO or the RF ablation of CTI-dependent AFL. A longer CTI was associated with a lower success rate regardless of energy source.

  17. FAQs about Catheter-Associated Bloodstream Infections

    MedlinePlus

    ... several weeks. A bloodstream infection can occur when bacteria or other germs travel down a “central line” and enter the blood. If you develop a catheter-associated blood- stream infection you may become ill with fevers and ...

  18. Management of catheter-related infection.

    PubMed

    Pagani, Jean-Luc; Eggimann, Philippe

    2008-02-01

    Nosocomial infections related to the development of catheter-related infections are a leading cause of morbidity and mortality among critically ill hospitalized patients. Despite important preventive efforts, these infections remain a daily concern for most clinicians. Significant improvements in the knowledge of their pathophysiology and diagnosis allow us to treat them more efficiently. Current practices, such as guidewire exchange of catheters suspected to be the source of clinical sepsis, are supported by indirect evidence only. Infected catheters should systematically be removed, but some of them may be salved by combining systemic and antibiotic-lock treatment. After reviewing some specific therapeutic aspects, we suggest a practical approach to manage catheter-related infections.

  19. Catheter-associated Staphylococcus aureus bacteremia.

    PubMed

    Gold, H S; Karchmer, A W

    1996-09-15

    The majority of cases of Staphylococcus aureus bacteremia are hospital-acquired, and most are associated with infected intravenous catheters. Preventive measures, early detection of infections, and strategies for effective treatment have become matters of increasing urgency.

  20. Intravascular Catheter-Related Bloodstream Infection

    PubMed Central

    Shah, Harshal; Bosch, Wendelyn; Thompson, Kristine M.; Hellinger, Walter C.

    2013-01-01

    Intravascular catheters required for the care of many hospitalized patients can give rise to bloodstream infection, a complication of care that has occurred most frequently in intensive care unit (ICU) settings. Elucidation of the pathogenesis of catheter-related bloodstream infections (CRBSIs) has guided development of effective diagnostic, management, and prevention strategies. When CRBSIs occur in the ICU, physicians must be prepared to recognize and treat them. Prevention of these infections requires careful attention to optimal catheter selection, insertion and maintenance, and to removal of catheters when they are no longer needed. This review provides a succinct summary of the epidemiology, pathogenesis, and microbiology of CRBSIs and a review of current guidance for the diagnosis, management, and prevention of these infections. PMID:24167648

  1. Designing a catheter skills training programme.

    PubMed

    Logan, Karen

    Karen Logan describes how a team of continence advisers designed and implemented a training programme that allows local nurses to meet the national occupational standards and competencies in catheterisation and catheter care.

  2. Fogarty catheter removal of nasal foreign bodies.

    PubMed

    Fox, J R

    1980-01-01

    The removal, without incident, of 14 nasal foreign bodies is described. None of the bodies was amenable to anterior instrumental extraction, and all were removed using a small-diameter Fogarty catheter.

  3. [Radiofrequency ablation in the treatment of focal atrial fibrillation using circumferential mapping and segmentary disconnection of pulmonary veins].

    PubMed

    Silva, Rose M F L; Mont, Lluís; Berruezo, Antonio; Fosch, Xavier; Wayar, Luis; Alvarenga, Nelson; Chueca, Enrique; Brugada, Josep

    2003-04-01

    The treatment of paroxysmal atrial fibrillation in patients without structural heart disease using radiofrequency ablation of pulmonary veins is a recently developed procedure with a good clinical success rate, although there have only been a few published series. We analyzed our results with this technique. The procedure was performed in 33 highly symptomatic patients with focal atrial fibrillation that had probably originated in the pulmonary veins. The electrophysiological study was carried out with a decapolar catheter inserted by transeptal catheterization. Ablation was performed using a 4-mm catheter and directed to the segments of the ostium of pulmonary veins where venous potentials with greatest precocity were recorded. Subsequent radiofrecuency applications were performed until pulmonary vein disconnection was achieved. Venous electrical activity was recorded in 59 of 115 pulmonary veins that were mapped (58 were disconnected). During a median follow-up of 180 days, 8 patients recurred and only 2 of these continue with repeat episodes. The success rate at short term was 74.2% and at mid-term was 93.5%. Nineteen patients continue to receive antiarrhythmic treatment innefective before the procedure. Two patients showed complications related to catheter manipulation during tansseptal catheterization, probably due to air embolism, that was resolved spontaneously without consequences. No patient showed pulmonary stenosis. Teatment of focal atrial fibrillation using circumferential mapping and radiofrecuency application in segments of the ostium of pulmonary veins is a highly effective procedure in selected patients and has potentially severe although infrequent complications.

  4. Computational Modeling of Open-Irrigated Electrodes for Radiofrequency Cardiac Ablation Including Blood Motion-Saline Flow Interaction

    PubMed Central

    González-Suárez, Ana; Berjano, Enrique; Guerra, Jose M.; Gerardo-Giorda, Luca

    2016-01-01

    Radiofrequency catheter ablation (RFCA) is a routine treatment for cardiac arrhythmias. During RFCA, the electrode-tissue interface temperature should be kept below 80°C to avoid thrombus formation. Open-irrigated electrodes facilitate power delivery while keeping low temperatures around the catheter. No computational model of an open-irrigated electrode in endocardial RFCA accounting for both the saline irrigation flow and the blood motion in the cardiac chamber has been proposed yet. We present the first computational model including both effects at once. The model has been validated against existing experimental results. Computational results showed that the surface lesion width and blood temperature are affected by both the electrode design and the irrigation flow rate. Smaller surface lesion widths and blood temperatures are obtained with higher irrigation flow rate, while the lesion depth is not affected by changing the irrigation flow rate. Larger lesions are obtained with increasing power and the electrode-tissue contact. Also, larger lesions are obtained when electrode is placed horizontally. Overall, the computational findings are in close agreement with previous experimental results providing an excellent tool for future catheter research. PMID:26938638

  5. Advanced Imaging Catheter: Final Project Report

    SciTech Connect

    Krulevitch, P; Colston, B; DaSilva, L; Hilken, D; Kluiwstra, J U; Lee, A P; London, R; Miles, R; Schumann, D; Seward, K; Wang, A

    2001-07-20

    Minimally invasive surgery (MIS) is an approach whereby procedures conventionally performed with large and potentially traumatic incisions are replaced by several tiny incisions through which specialized instruments are inserted. Early MIS, often called laparoscopic surgery, used video cameras and laparoscopes to visualize and control the medical devices, which were typically cutting or stapling tools. More recently, catheter-based procedures have become a fast growing sector of all surgeries. In these procedures, small incisions are made into one of the main arteries (e.g. femoral artery in the thigh), and a long thin hollow tube is inserted and positioned near the target area. The key advantage of this technique is that recovery time can be reduced from months to a matter of days. In the United States, over 700,000 catheter procedures are performed annually representing a market of over $350 million. Further growth in this area will require significant improvements in the current catheter technology. In order to effectively navigate a catheter through the tortuous vessels of the body, two capabilities must exist: imaging and positioning. In most cases, catheter procedures rely on radiography for visualization and manual manipulation for positioning of the device. Radiography provides two-dimensional, global images of the vasculature and cannot be used continuously due to radiation exposure to both the patient and physician. Intravascular ultrasound devices are available for continuous local imaging at the catheter tip, but these devices cannot be used simultaneously with therapeutic devices. Catheters are highly compliant devices, and manipulating the catheter is similar to pushing on a string. Often, a guide wire is used to help position the catheter, but this procedure has its own set of problems. Three characteristics are used to describe catheter maneuverability: (1) pushability -- the amount of linear displacement of the distal end (inside body) relative to

  6. Catheter-directed interventions for pulmonary embolism

    PubMed Central

    Zarghouni, Mehrzad; Charles, Hearns W.; Maldonado, Thomas S.

    2016-01-01

    Pulmonary embolism (PE), a potentially life-threatening entity, can be treated medically, surgically, and percutaneously. In patients with right ventricular dysfunction (RVD), anticoagulation alone may be insufficient to restore cardiac function. Because of the morbidity and mortality associated with surgical embolectomy, clinical interest in catheter-directed interventions (CDI) has resurged. We describe specific catheter-directed techniques and the evidence supporting percutaneous treatments. PMID:28123985

  7. Evaluation of antiseptic-impregnated central venous catheters for prevention of catheter-related infection in intensive care unit patients.

    PubMed

    Sheng, W H; Ko, W J; Wang, J T; Chang, S C; Hsueh, P R; Luh, K T

    2000-09-01

    Central venous catheterization represents a significant medical advancement, particularly in the treatment of critical ill. However, there is a high risk of central venous catheters-related infection. A novel antiseptic central venous catheter, made of polyurethane and impregnated with chlorhexidine and silver sulfadiazine, was developed to reduce the risk of catheters-related infection. In this study, we did a randomized clinical study to determine the efficacy by using antiseptic catheters for the prevention of central venous catheters-related infection in the intensive care units. A total of 204 patients with 235 central venous catheters were studied at the surgical intensive care units at National Taiwan University Hospital between November 1998 and June 1999. Participants received either a standard triple-lumen polyurethane catheter or an antiseptic catheter (Arrow International, Reading, Pennsylvania, USA). Both were indistinguishable from each other. Compared to standard polyurethane catheters, antiseptic catheters were less likely to be colonized by microorganisms when they were cultured at the removal (8.0 versus 20.0 colonized catheters per 100 catheters; relative risk 0.34 [95% CI, 0.15 to 0.74]; p<0.01). There was no significant differences between both groups in catheter-related infections (0.9 versus 4.9 infections per 100 catheters; relative risk 0.17 [95% CI, 0.03 to 1.15]; p = 0.07). Gram-positive cocci and fungi were more likely to colonize in the standard polyurethane catheters (p = 0.06 and 0.04, compared to antiseptic catheters respectively). Two of our cases in the control group died directly due to catheter-related candidemia. No adverse reactions such as hypersensitivity or leukopenia were found in the antiseptic catheter group. Our study showed that central venous catheters with antiseptic coating were safe and had less risk of colonization of bacteria and fungi than standard catheters in the critically ill patients.

  8. Catheter ablation for ventricular tachycardia following surgical treatment of pulmonary stenosis with intact ventricular septum.

    PubMed

    Hou, Bingbo; Zheng, Lihui; Niu, Guodong; Wu, Lingmin; Qiao, Yu; Sun, Wei; Ding, Ligang; Chen, Gang; Zhang, Shu; Liew, Reginald; Yao, Yan

    2016-12-01

    This study was aimed to report the characteristics and treatment of ventricular tachycardia (VT) following surgical treatment of pulmonary stenosis with intact ventricular septum. Five patients underwent radiofrequency catheter ablation for sustained monomorphic left bundle branch block (LBBB) type VT who previously underwent surgical treatment of pulmonary stenosis. Except stimulation, voltage and activation mapping was performed using three-dimensional (3D) electro-anatomic mapping and ablation was applied accordingly. Four VTs were induced during EP study. Two VTs were focal and the earliest activity was targeted in the right ventricular apex (RVA). The other two VTs were reentrant and the critical isthmus located in the mid-lateral wall and anterior wall of right ventricle, respectively. Ablation abolished all inducible VTs in four patients. In the patient whose VT was non-inducible, radiofrequency (RF) energy was delivered to the RVA where pacing mapping matched the clinical VT. One focal VT recurred 60 months after the initial RF ablation. Repeat mapping and ablation was performed and no VT recurred over a 24-month period. The mechanism of VT following surgical treatment of pulmonary stenosis can be either focal or reentrant. Ablation of this subgroup of VT is feasible. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

  9. MR-trackable intramyocardial injection catheter.

    PubMed

    Karmarkar, P V; Kraitchman, D L; Izbudak, I; Hofmann, L V; Amado, L C; Fritzges, D; Young, R; Pittenger, M; Bulte, J W M; Atalar, E

    2004-06-01

    There is growing interest in delivering cellular agents to infarcted myocardium to prevent postinfarction left ventricular remodeling. MRI can be effectively used to differentiate infarcted from healthy myocardium. MR-guided delivery of cellular agents/therapeutics is appealing because the therapeutics can be precisely targeted to the desired location within the infarct. In this study, a steerable intramyocardial injection catheter that can be actively tracked under MRI was developed and tested. The components of the catheter were arranged to form a loopless RF antenna receiver coil that enabled active tracking. Feasibility studies were performed in canine and porcine myocardial infarction models. Myocardial delayed-enhancement (MDE) imaging identified the infarcted myocardium, and real-time MRI was used to guide left ventricular catheterization from a carotid artery approach. The distal 35 cm of the catheter was seen under MRI with a bright signal at the distal tip of the catheter. The catheter was steered into position, the distal tip was apposed against the infarct, the needle was advanced, and a bolus of MR contrast agent and tissue marker dye was injected intramyocardially, as confirmed by imaging and postmortem histology. A pilot study involving intramyocardial delivery of magnetically labeled stem cells demonstrated the utility of the active injection catheter system. Copyright 2004 Wiley-Liss, Inc.

  10. The optimal radiofrequency temperature in radiofrequency thermocoagulation for idiopathic trigeminal neuralgia: A cohort study.

    PubMed

    Tang, Yuan-Zhang; Yang, Li-Qiang; Yue, Jian-Ning; Wang, Xiao-Ping; He, Liang-Liang; Ni, Jia-Xiang

    2016-07-01

    Our previous study evaluated the effectiveness and safety of radiofrequency thermocoagulation (RFT) of trigeminal gasserian ganglion for idiopathic trigeminal neuralgia (ITN). The aim of this study was to evaluate the optimal radiofrequency temperature of computed tomography (CT)-guided RFT for treatment of ITN. A retrospective study of patients with ITN treated with a single CT-guided RFT procedure between January 2002 and December 2013. Patients were divided into ≤75 °C, 75 °C, and ≥80 °C groups according to the highest radiofrequency temperature used. Pain relief was graded from poor to excellent, and facial numbness/dysesthesia from I (absent) to IV (most severe). A total of 1161 RFT procedures were undertaken in the 1137 patients. The mean follow-up time was 46 ± 31 months. There were no significant differences in the rate of excellent pain relief according to the radiofrequency temperature used. However, more patients experienced with no facial numbness or facial numbness gradually resolved and those patients treated at 75 °C had a lower rate of grade IV facial numbness/dysesthesia than other groups. The optimal radiofrequency temperature to maximize pain relief and minimize facial numbness or dysesthesia may be 75 °C, but this requires confirmation.

  11. The optimal radiofrequency temperature in radiofrequency thermocoagulation for idiopathic trigeminal neuralgia

    PubMed Central

    Tang, Yuan-Zhang; Yang, Li-Qiang; Yue, Jian-Ning; Wang, Xiao-Ping; HE, Liang-Liang; NI, Jia-Xiang

    2016-01-01

    Abstract Objective: Our previous study evaluated the effectiveness and safety of radiofrequency thermocoagulation (RFT) of trigeminal gasserian ganglion for idiopathic trigeminal neuralgia (ITN). The aim of this study was to evaluate the optimal radiofrequency temperature of computed tomography (CT)-guided RFT for treatment of ITN. Methods: A retrospective study of patients with ITN treated with a single CT-guided RFT procedure between January 2002 and December 2013. Patients were divided into ≤75 °C, 75 °C, and ≥80 °C groups according to the highest radiofrequency temperature used. Pain relief was graded from poor to excellent, and facial numbness/dysesthesia from I (absent) to IV (most severe). Results: A total of 1161 RFT procedures were undertaken in the 1137 patients. The mean follow-up time was 46 ± 31 months. There were no significant differences in the rate of excellent pain relief according to the radiofrequency temperature used. However, more patients experienced with no facial numbness or facial numbness gradually resolved and those patients treated at 75 °C had a lower rate of grade IV facial numbness/dysesthesia than other groups. Conclusions: The optimal radiofrequency temperature to maximize pain relief and minimize facial numbness or dysesthesia may be 75 °C, but this requires confirmation. PMID:27428194

  12. Comparison of a Balloon Guide Catheter and a Non-Balloon Guide Catheter for Mechanical Thrombectomy.

    PubMed

    Velasco, Aglaé; Buerke, Boris; Stracke, Christian P; Berkemeyer, Shoma; Mosimann, Pascal J; Schwindt, Wolfram; Alcázar, Pedro; Cnyrim, Christian; Niederstadt, Thomas; Chapot, René; Heindel, Walter

    2016-07-01

    Purpose To evaluate the effectiveness of mechanical thrombectomy with the use of a stent retriever in acute ischemic stroke, performed by using a balloon guide catheter or non-balloon guide catheter. Materials and Methods In accordance with the institutional review board approval obtained at the two participating institutions, retrospective analysis was performed in 183 consecutive patients treated between 2013 and 2014 for occlusions in the middle cerebral artery or carotid terminus by using a stent retriever with a balloon guide catheter (n = 102) at one center and a non-balloon guide catheter (n = 81) at the other center. Data on procedure duration, number of passes, angiographic findings, type of stent retriever used, and expertise of the operators were collected. Successful recanalization was defined as grade 3 or 2b modified Treatment in Cerebral Ischemia recanalization accomplished in up to three passes. Univariate and multivariate subgroup analyses were conducted to control for the confounding variables of prior thrombolysis, location of occlusion, and operator expertise. Results Successful recanalization with the balloon guide catheter was achieved in 89.2% of thrombectomies (91 of 102) versus 67.9% (55 of 81) achieved with the non-balloon guide catheter (P = .0004). The one-pass thrombectomy rate with the balloon guide catheter was significantly higher than for that with the non-balloon guide catheter (63.7% [65 of 102] vs 35.8% [29 of 81], respectively; P = .001). The procedure duration was significantly shorter by using the balloon guide catheter than the non-balloon guide catheter (median, 20.5 minutes vs 41.0 minutes, respectively; P < .0001). Conclusion The effectiveness of mechanical thrombectomy with stent retrievers in acute ischemic stroke in the anterior circulation in terms of angiographic results and procedure duration was improved when performed in combination with the balloon guide catheter. (©) RSNA, 2016.

  13. Fraxelated radiofrequency device for acne scars

    NASA Astrophysics Data System (ADS)

    Rao, Babar K.; Khokher, Sairah

    2012-09-01

    Acne scars can be improved with various treatments such as topical creams, chemical peels, dermal fillers, microdermabrasion, laser, and radiofrequency devices. Some of these treatments especially lasers and deep chemical peels can have significant side effects such as post inflammatory hyperpigmentation in darker skin types. Fraxelated RF Laser devices have been reported to have lower incidence of side effects in all skin phototypes. Nine patients between ages 18 and 35 of various skin phototypes were selected from a private practice and treated with a RF fraxelated device (E-matrix) for acne scars. Outcomes were measured by physician observation, subjective feedback received by patients, and comparison of before and after photographs. In this small group of patients with various skin phototypes, fraxelated radiofrequency device improved acne scars with minimal side effects and downtime.

  14. Skin tightening with fractional lasers, radiofrequency, Smartlipo.

    PubMed

    Collawn, Sherry S

    2010-05-01

    Skin tightening occurs with the use of fractional lasers, radiofrequency, and Smartlipo. The fractional lasers Fraxel (1550 nm; Solta Medical, Inc., Hayward, CA) and Affirm (1440 nm, 1320 nm) (Cynosure, Westford, MA) when used in combination tighten skin and lessen solar keratoses, and improve acne scars. With radiofrequency, further tightening occurs. Smartlipo (Cynosure, Westford, MA) (1064 nm or the newer MPX with combined 1064 nm and 1320 nm) results in skin tightening and has been very helpful in improving skin tightness and smoothness on the neck either singularly or in combination with the above procedures; and with the addition of the Affirm fractional CO2 laser (Cynosure, Westford, MA), further skin improvement and tightening occurs.

  15. Pulmonary radiofrequency ablation (Part 1): current state.

    PubMed

    Plasencia Martínez, J M

    2015-01-01

    The risks involved in surgical treatment and conventional radiotherapy in patients with early lung cancer or lung metastases often make these treatments difficult to justify. However, on the other hand, it is also unacceptable to allow these lesions to evolve freely because, left untreated, these neoplasms will usually lead to the death of the patient. In recent years, alternative local therapies have been developed, such as pulmonary radiofrequency ablation, which has proven to increase survival with a minimal risk of complications. There are common recommendations for these treatments, and although the specific indications for using one technique or another have yet to be established, there are clearly defined situations that will determine the outcome of the treatment. It is important to know these situations, because appropriate patient selection is essential for therapeutic success. This article aims to describe the characteristics and constraints of pulmonary radiofrequency ablation and to outline its role in thoracic oncology in light of the current evidence.

  16. Radiofrequency and microwave radiation in the microelectronics industry.

    PubMed

    Cohen, R

    1986-01-01

    The microscopic precision required to produce minute integrated circuits is dependent on several processes utilizing radiofrequency and microwave radiation. This article provides a review of radiofrequency and microwave exposures in microelectronics and of the physical and biologic properties of these types of radiation; summarizes the existing, relevant medical literature; and provides the clinician with guidelines for diagnosis and treatment of excessive exposures to microwave and radiofrequency radiation.

  17. Magnetocardiographically-guided catheter ablation.

    PubMed

    Fenici, R R; Covino, M; Cellerino, C; Di Lillo, M; De Filippo, M C; Melillo, G

    1995-12-01

    After more than 30 years since the first magnetocardiographic (MCG) recording was carried out with induction coils, MCG is now approaching the threshold of clinical use. During the last 5 years, in fact, there has been a growing interest of clinicians in this new method which provides an unrivalled accuracy for noninvasive, three-dimensional localization of intracardiac source. An increasing number of laboratories are reporting data validating the use of MCG as an effective method for preoperative localization of arrhythmogenic substrates and for planning the best catheter ablation approach for different arrhythmogenic substrates. In this article, available data from literature have been reviewed. We consider the clinical use of MCG to localize arrhythmogenic substrates in patients with Wolff-Parkinson-White syndrome and in patients with ventricular tachycardia in order to assess the state-of-the-art of the method on a large number of patients. This article also addresses some suggestions for industrial development of more compact, medically oriented MCG equipments at reasonable cost.

  18. Superconducting surface impedance under radiofrequency field

    DOE PAGES

    Xiao, Binping P.; Reece, Charles E.; Kelley, Michael J.

    2013-04-26

    Based on BCS theory with moving Cooper pairs, the electron states distribution at 0K and the probability of electron occupation with finite temperature have been derived and applied to anomalous skin effect theory to obtain the surface impedance of a superconductor under radiofrequency (RF) field. We present the numerical results for Nb and compare these with representative RF field-dependent effective surface resistance measurements from a 1.5 GHz resonant structure.

  19. Superconducting surface impedance under radiofrequency field

    NASA Astrophysics Data System (ADS)

    Xiao, B. P.; Reece, C. E.; Kelley, M. J.

    2013-07-01

    Based on BCS theory with moving Cooper pairs, the electron states distribution at 0 K and the probability of electron occupation with finite temperature have been derived and applied to anomalous skin effect theory to obtain the surface impedance of a superconductor under radiofrequency (RF) field. We present the numerical results for Nb and compare these with representative RF field-dependent effective surface resistance measurements from a 1.5 GHz resonant structure.

  20. Radio-frequency association of Efimov trimers.

    PubMed

    Lompe, Thomas; Ottenstein, Timo B; Serwane, Friedhelm; Wenz, Andre N; Zürn, Gerhard; Jochim, Selim

    2010-11-12

    The quantum mechanical three-body problem is one of the fundamental challenges of few-body physics. When the two-body interactions become resonant, an infinite series of universal three-body bound states is predicted to occur, whose properties are determined by the strength of the two-body interactions. We used radio-frequency fields to associate Efimov trimers consisting of three distinguishable fermions. The measurements of their binding energy are consistent with theoretical predictions that include nonuniversal corrections.

  1. Radiofrequency Microtenotomy for Elbow Epicondylitis: Midterm Results.

    PubMed

    Tasto, James P; Richmond, John M; Cummings, Jeffrey R; Hardesty, Renee; Amiel, David

    2016-01-01

    We conducted a prospective, nonrandomized, single-center clinical study to evaluate the safety and midterm effectiveness of microtenotomy using a radiofrequency probe to treat chronic tendinosis of the elbow. All patients had failed conservative treatment for 6 months. The radiofrequency-based microtenotomy was performed using the Topaz Microdebrider (ArthroCare). Patients were followed annually for up to 9 years postoperatively. Pain status was documented using a visual analog scale self-reported measure. Eighty consecutive patients with tendinosis of the elbow were enrolled; 69 patients were treated for lateral epicondylitis and 11 for medial epicondylitis. The duration of follow-up ranged from 6 months to 9 years (mean, 2.5 years). Ninety-one percent of the patients reported a successful outcome. Within the lateral epicondylitis group, the preoperative visual analog scale improved from 6.9 to 1.3 postoperatively and demonstrated an 81% improvement (P ≤ .01). For the medial epicondylitis patients, the preoperative visual analog scale improved from 6.1 to 1.3 after surgery, a 79% improvement (P ≤ .01). No complications were reported. Radiofrequency-based microtenotomy is a safe and effective procedure for elbow epicondylitis. The results are durable with successful outcomes observed at 9 years after surgery.

  2. Catheter ablation of organized atrial arrhythmias in orthotopic heart transplantation.

    PubMed

    Mouhoub, Yamina; Laredo, Mikael; Varnous, Shaida; Leprince, Pascal; Waintraub, Xavier; Gandjbakhch, Estelle; Hébert, Jean-Louis; Frank, Robert; Maupain, Carole; Pavie, Alain; Hidden-Lucet, Françoise; Duthoit, Guillaume

    2017-07-21

    Organized atrial arrhythmias (OAAs) are common after orthotopic heart transplantation (OHT). Some controversies remain about their clinical presentation, relationship with atrial anastomosis and electrophysiologic features. The objectives of this retrospective study were to determine the mechanisms of OAAs after OHT and describe the outcomes of radiofrequency catheter ablation (RFCA). Thirty consecutive transplanted patients (mean age 48 ± 17 years, 86.6% male) underwent 3-dimensional electroanatomic mapping and RFCA of their OAA from 2004 to 2012 at our center. Twenty-two patients had biatrial anastomosis and 8 had bicaval anastomosis. Macro-reentry was the arrhythmia mechanism for 96% of patients. The electrophysiologic diagnoses were: cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL) in 93% of patients (n = 28); perimitral AFL in 3% (n = 1); and focal atrial tachycardia (FAT) in 3% (n = 1). In 5 patients with biatrial anastomosis, a right FAT was inducible. Primary RFCA success was obtained in 93% of patients. Mean follow-up time was 39 ± 26.8 months. Electrical repermeation between recipient and donor atria, present in 20% of patients (n = 6), did not account for any of the OAAs observed. Survival without OAA relapse at 12, 24 and 60 months was 93%, 89% and 79%, respectively. CTI-dependent AFL accounted for most instances of OAA after OHT, regardless of anastomosis type. Time from transplantation to OAA was shorter with bicaval than with biatrial anastomosis. RFCA was safe and provided good long-term results. Copyright © 2017 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

  3. [Appropriate and inappropriate use of indwelling urinary catheters].

    PubMed

    Janzen, Jolien; Geerlings, Suzanne E

    2012-01-01

    Many hospitalized patients receive a urinary catheter during their stay. In 21-54% of patients, however, there is no appropriate indication for this. The most significant complication caused by the use of urinary catheters is the development of a urinary tract infection (UTI), one of the most common nosocomial infections. In 71-80% of hospital acquired UTIs a urinary catheter is present. The duration of the presence of a catheter is the major risk factor for catheter-associated UTI. Reducing the number of inappropriate catheterisations is an effective way of preventing catheter-related UTIs. Inappropriate use of indwelling urinary catheters can be reduced by maintaining strict guidelines on justifiable indications for inserting a urinary catheter, verifying daily whether the indication still applies, and by timely removal of the catheter when it is not or no longer needed.

  4. Reducing inappropriate urinary catheter use: quality care initiatives.

    PubMed

    Buckley, Catherine; Clements, Charlotte; Hopper, Adrian

    Healthcare-acquired urinary infection presents a substantial burden for patients and the healthcare system. Urinary tract infections have not gained the same level of media attention as other healthcare-associated infections, yet interventions to reduce urinary catheter use are one of the top ten recommended patient safety strategies. To improve practice around urinary catheter placement and removal requires interventions to change the expectations and habits of nurses, medical teams and patients regarding the need for a urinary catheter. In the authors' trust, a redesign of the existing urinary catheter device record was undertaken to help avoid unnecessary placement of catheters, and resulted in a reduction of urinary catheters in situ longer than 48 hours. Other strategies included implementation of catheter rounds in a high-usage area, and credit-card-sized education cards. A catheter 'passport' was introduced for patients discharged with a catheter to ensure information for insertion and ongoing use were effectively communicated.

  5. Practical approach to catheter-related bloodstream infections in paediatrics

    PubMed Central

    Robinson, Joan

    2005-01-01

    Catheter-related bloodstream infections (CRBIs) are a common problem in paediatrics. Sterile insertion and proper care of the catheter is likely more important than the type of catheter in determining the rate of CRBIs. The accuracy of the diagnosis of CRBIs can be improved by comparing the time to positivity or the concentration of organisms in blood drawn through the catheter with blood drawn from other sites, or by changing the catheter over a guidewire and culturing the removed catheter. When a CRBI is suspected, the catheter should be removed if it is no longer required, the child is hemodynamically unstable, there are metastatic foci of infection, the infecting organism is Candida or a mycobacterium, or there is a tunnel infection. The necessity for catheter removal is controversial if the infecting organism is Staphylococcus aureus or a Gram-negative organism. In most other situations, the catheter only needs to be removed if bacteremia persists despite appropriate antibiotic use. PMID:19668658

  6. Antibiotic lock for treatment of tunneled hemodialysis catheter bacteremia.

    PubMed

    Maya, Ivan D

    2008-01-01

    Catheter-related bacteremia is a major cause of morbidity and mortality among catheter-dependent hemodialysis patients. Microorganism biofilm matrix formation in the catheter is the pathogenic process of this entity. Administration of systemic antibiotics and removal of the offending catheter is the most logical treatment. This article discusses an alternative option, instillation of an antibiotic-lock solution into the lumen of the catheter plus systemic antibiotic therapy. Recent studies suggest that this strategy could treat the infection and salvage the catheter, thus avoiding the need for further interventional procedures including but not limited to the removal of the catheter, placement of a temporary catheter, and finally placement of a new permanent catheter. The implementation of this effective approach will reduce morbidity and possibly reduce the cost and interventions associated with it.

  7. Audit of catheter-associated UTI using silver alloy-coated Foley catheters.

    PubMed

    Seymour, Coral

    Catheter-associated urinary tract infection (CAUTI) is the most common and most costly healthcare-associated infection, and possibly the most preventable (Salgado et al, 2003). The Cochrane Review of silver alloy-coated Foley catheters concluded that they are successful at reducing the rate of this healthcare-associated infection, which can be potentially fatal (Brosnahan et al, 2004). This article discusses the merits of using the silver alloy-coated Foley catheter in reducing the risk of CAUTI in an acute general hospital. A pre- and post-intervention design was used to audit CAUTI rates. During the pre-intervention period of 10 weeks, the Trust's standard catheters were used and CAUTI rates captured. Silver alloy-coated Foley catheters were introduced and their use monitored for a further period of 10 weeks. A total of 117 newly catheterized patients were actively monitored for signs and symptoms of CAUTI. The audit met and exceeded its aim of reducing the CAUTI rate by 20&. The CAUTI risk rate and device rate fell during the evaluation period. The use of the silver alloy-coated Foley catheters proved to be cost-effective given the recognized additional costs of CAUTI and prolonged in-patient stay (Plowman et al, 1999). Given the results of this audit it is recommended that the silver alloy-coated Foley catheter be the catheter of choice for use with acute patient admissions requiring short-term catheterization.

  8. Uptake of drugs by catheters: the influence of the drug molecule on sorption by polyurethane catheters.

    PubMed

    Smith, J C; Davies, M C; Melia, C D; Denyer, S P; Derrick, M R

    1996-08-01

    The sorption of drugs by indwelling intravenous catheters may have clinical consequences both by alteration of the dose received by the patient and by physically affecting the catheter materials themselves which may lead to changes in mechanical properties and biocompatibility. Studies of drug sorption to new catheter materials are therefore important. Pellethane, a polyurethane increasingly used in vascular access catheters, is as yet little studied in terms of its capacity for drug sorption. In this work a range of drugs known to be sorbed by PVC infusion sets were studied with respect to their sorption by Pellethane catheters. Standard lengths of catheter were incubated with solutions of drugs and samples of the solution were taken at intervals, assayed spectrophotometrically and compared with control solutions incubated without catheter. Losses from solution of up to 93% were found after 24 h. A series of highly sorbing and clinically relevant drugs was identified and their uptake was studied until equilibrium had been reached. A correlation was evident between the octanol/water partition coefficient and the fraction of drug taken up from solution at equilibrium, with the more hydrophobic drugs being taken up to a greater extent by the catheter.

  9. Conversion of Non-Tunneled to Tunneled Hemodialysis Catheters

    SciTech Connect

    Ha, Thuong G. Van Fimmen, Derek; Han, Laura; Funaki, Brian S.; Santeler, Scott; Lorenz, Jonathan

    2007-04-15

    Purpose. To determine the safety and efficacy of conversion of non-tunneled (temporary) catheters to tunneled catheters in hemodialysis patients. Methods. A retrospective review of 112 consecutive conversions in 111 patients was performed over a period of 4 years. Fourteen patients were lost to follow-up. The remaining 97 patients had clinical follow-up. Temporary catheters were converted to tunneled catheters utilizing the same internal jugular venotomy sites and a modified over-the-wire technique with use of a peel-away sheath . Follow-up clinical data were reviewed. Results. Technical success was achieved in all 112 procedures. None of the 97 patients with follow-up suffered early infection within 30 days. The total number of follow-up catheter days was 13,659 (range 2-790). Cases of confirmed and suspected bacteremia requiring catheter removal occurred at a frequency of 0.10 per 100 catheter days. Suspected catheter infection treated with antibiotics but not requiring catheter intervention occurred at a frequency of 0.04 per 100 catheter days. Frequency of all suspected or confirmed infections was 0.14 per 100 catheter days. Catheter interventions as a result of poor blood flow, inadvertent removal, catheter fracture, or kinking occurred at a rate of 0.18 per 100 catheter days. Life table analysis revealed primary patency rates of 86%, 64%, and 39% at 30 days, 90 days, and 180 days, respectively. Conclusion. Conversion of temporary catheters to tunneled catheters using the pre-existing venotomy sites is safe and has low rates of infection and malfunction. These rates are comparable to previously published rates for tunneled catheters placed de novo and tunneled catheter exchanges.

  10. Bradycardia during Transradial Cardiac Catheterization due to Catheter Manipulation: Resolved by Catheter Removal

    PubMed Central

    Kumar, Vishesh; Stys, Adam

    2017-01-01

    Purpose. To report the resolution of bradycardia encountered during transradial cardiac catheterization through the catheter pullback technique in two cases. Case Report. A 62-year-old male and an 81-year-old male underwent coronary angiogram to evaluate for coronary artery disease and as a result of positive stress test, respectively. Upon engagement of the FL 3.5 catheter into the ascending aorta through the transradial approach, the first case developed bradycardia with a heart rate of 39 beats per minute. The second case developed profound bradycardia with a heart rate of 25 beats per minute upon insertion of the 5 Fr FL 3.5 catheter near the right brachiocephalic trunk through the right radial access. Conclusion. Bradycardia can be subsided by removal of the catheter during catheter manipulation in patients undergoing transradial coronary angiogram if there is a suspicion of excessive stretching of aortic arch receptors and/or carotid sinus receptors. PMID:28348915

  11. Experience of robotic catheter ablation in humans using a novel remotely steerable catheter sheath

    PubMed Central

    Wallace, Daniel T.; Goldenberg, Alex S.; Peters, Nicholas S.; Davies, D. Wyn

    2008-01-01

    Background A novel remotely controlled steerable guide catheter has been developed to enable precise manipulation and stable positioning of any eight French (Fr) or smaller electrophysiological catheter within the heart for the purposes of mapping and ablation. Objective To report our initial experience using this system for remotely performing catheter ablation in humans. Methods Consecutive patients attending for routine ablation were recruited. Various conventional diagnostic catheters were inserted through the left femoral vein in preparation for treating an accessory pathway (n = 1), atrial flutter (n = 2) and atrial fibrillation (n = 7). The steerable guide catheter was inserted into the right femoral vein through which various irrigated and non-irrigated tip ablation catheters were used. Conventional endpoints of loss of pathway conduction, bidirectional cavotricuspid isthmus block and four pulmonary vein isolation were used to determine acute procedural success. Results Ten patients underwent remote catheter ablation using conventional and/or 3D non-fluoroscopic mapping technologies. All procedural endpoints were achieved using the robotic control system without manual manipulation of the ablation catheter. There was no major complication. A radiation dosimeter positioned next to the operator 2.7 m away from the X-ray source showed negligible exposure despite a mean cumulative dose area product of 7,281.4 cGycm2 for all ten ablation procedures. Conclusions Safe and clinically effective remote navigation of ablation catheters can be achieved using a novel remotely controlled steerable guide catheter in a variety of arrhythmias. The system is compatible with current mapping and ablation technologies Remote navigation substantially reduces radiation exposure to the operator. Electronic supplementary material The online version of this article (doi:10.1007/s10840-007-9184-z) contains supplementary material, which is available to authorized users

  12. Malfunctioning central venous catheters in children: a diagnostic approach

    PubMed Central

    Barnacle, Alex; Arthurs, Owen J.; Roebuck, Derek

    2007-01-01

    Central venous access is increasingly becoming the domain of the radiologist, both in terms of the insertion of central venous catheters (CVCs) and in the subsequent management of these lines. This article seeks to provide an overview of the CVC types available for paediatric patients and a more detailed explanation of the spectrum of complications that may lead to catheter malfunction. A standard catheter contrast study or ‘linogram’ technique is described. The normal appearances of such a study and a detailed pictorial review of abnormal catheter studies are provided, together with a brief overview of how information from catheter investigations can guide the management of catheter complications. PMID:17932667

  13. Midline catheters: the middle ground of intravenous therapy administration.

    PubMed

    Anderson, N Richard

    2004-01-01

    Evangelical Community Hospital at Lewisburg, Pennsylvania, is a small community hospital with 110 beds. This organization sought a device to bridge between the short peripheral catheter and the peripherally inserted central catheter. The midline catheter provided an answer to this dilemma. However, a literature search for midline catheters yielded only four published articles, and only one of these was related to outcomes. The drugs used and the type of patients treated at Evangelical Community Hospital provided a challenge for the infusion therapist. This article examines the management of the patients who fell into a midlength of stay, and for whom both the short peripheral catheter and the peripherally inserted central catheter were inappropriate.

  14. [Swan Ganz catheter. Experts opinion].

    PubMed

    Cohen Arazi, Hernán; Nani, Sebastián; Giorgi, Mariano; Guardiani, Fernando; Caturla, Nicolás; Benzadón, Mariano

    2014-01-01

    Investigators have raised doubts as to the safety of the Swan Ganz catheter (SGC). In order to define the point of view of cardiologists in our country, the Argentine Society of Cardiology's Emergency Council organized a meeting to analyze their views in different settings (non-cardiac surgery, cardiac surgery, acute coronary syndromes and heart failure) using the RAND-UCLA appropriateness method. A detailed review with the scientific evidence was sent to the experts in cardiology prior to the meeting in the SAC auditorium where the panellists selected the clinical variables create the specific situations. These hypothetic situations were resent to the panellists at a second stage for their individual evaluation, rating the benefit-to-harm ratio of the procedure on a scale of 1 to 9 (1 meant that the expected harms greatly outweighed the expected benefits, and 9 that the expected benefits greatly outweighed the expected harms, 5 could mean either that the harms and benefits were roughly equal). Two experts analyzed the results, describing the agreement/disagreement ratio. Finally, each indication was classified as "appropriate" "uncertain" or "inappropriate" ,for the procedure in accordance with the panelists' median score: median scores in the 1-3 range were classified as inappropriate, those in the 4-6 range as uncertain, and those in the 7-9 range as appropriate. We observed high disagreement rates in SGC indications between cardiologists. However, the panelists were in favor of SGC use when situations included shock and myocardial dysfunction, especially in the presence of organic dysfunction. There were some situations when panelists considered SGC not useful, in patients without organ failure.

  15. A novel adaptation of laparoscopic Tenckhoff catheter insertion technique to enhance catheter stability and function in automated peritoneal dialysis.

    PubMed

    Meier, Clemens M; Poppleton, Aaron; Fliser, Danilo; Klingele, Matthias

    2014-04-01

    Automated peritoneal dialysis (APD) normally takes place overnight. Maintaining a stable PD catheter position, independent of body position, omental wrapping or catheter displacement secondary to bowel movements is essential in maintaining effective catheter function. We developed a new procedure of catheter placement through combining and adapting several previously described operative techniques including laparoscopic placement of a curled double cuff Tenckhoff catheter with subcutaneous tunneling superior to the rectus sheet, an oblique course through the abdominal wall, deep entry into the pelvic peritoneum and directed placement of the curled tip within the pouch of Douglas. Retrospective analysis of catheter function was conducted, evaluating catheter position, function, complication rate and catheter survival against findings for current insertion techniques described within literature. Between March 2009 and November 2011, 54 patients underwent PD catheter insertion. The observation period was an average of 343 ± 273 days. All patients received abdominal plain film showing optimal catheter position in 89 %. Reported catheter function was very good in 85.2 %, with no or few alarms per week during APD, moderate in 9.3 % with occasional minor dysfunctions (≤ 2 alarms per night), and poor in 5.6 %, with regular alarm disturbance. In one case, primary dysfunction led to catheter replacement. At completion, stable catheter function with occasional minor dysfunction was achieved in 52 of 54 cases. Catheter-related complications (leakage, hydrocele formation, infection and need for replacement) were observed in 14.8 %. At the end of the observation period, 55.6 % of catheters remained in use. Patient dropout occurred through death (18.5 %), renal transplantation (7.4 %), renal recovery (1.9 %), removal secondary to infection or dysfunction (9.3 %) and conversion to HD due to poor dialysis quality (7.4 %). The above technique combines and optimises previously

  16. Optimization of Catheter Ablation of Atrial Fibrillation: Insights Gained from Clinically-Derived Computer Models

    PubMed Central

    Zhao, Jichao; Kharche, Sanjay R.; Hansen, Brian J.; Csepe, Thomas A.; Wang, Yufeng; Stiles, Martin K.; Fedorov, Vadim V.

    2015-01-01

    Atrial fibrillation (AF) is the most common heart rhythm disturbance, and its treatment is an increasing economic burden on the health care system. Despite recent intense clinical, experimental and basic research activity, the treatment of AF with current antiarrhythmic drugs and catheter/surgical therapies remains limited. Radiofrequency catheter ablation (RFCA) is widely used to treat patients with AF. Current clinical ablation strategies are largely based on atrial anatomy and/or substrate detected using different approaches, and they vary from one clinical center to another. The nature of clinical ablation leads to ambiguity regarding the optimal patient personalization of the therapy partly due to the fact that each empirical configuration of ablation lines made in a patient is irreversible during one ablation procedure. To investigate optimized ablation lesion line sets, in silico experimentation is an ideal solution. 3D computer models give us a unique advantage to plan and assess the effectiveness of different ablation strategies before and during RFCA. Reliability of in silico assessment is ensured by inclusion of accurate 3D atrial geometry, realistic fiber orientation, accurate fibrosis distribution and cellular kinetics; however, most of this detailed information in the current computer models is extrapolated from animal models and not from the human heart. The predictive power of computer models will increase as they are validated with human experimental and clinical data. To make the most from a computer model, one needs to develop 3D computer models based on the same functionally and structurally mapped intact human atria with high spatial resolution. The purpose of this review paper is to summarize recent developments in clinically-derived computer models and the clinical insights they provide for catheter ablation. PMID:25984605

  17. Identification of transmural necrosis along a linear catheter ablation lesion during atrial fibrillation and sinus rhythm.

    PubMed

    Sanchez, Javier E; Kay, G Neal; Benser, Michael E; Hall, Jeffrey A; Walcott, Gregory P; Smith, William M; Ideker, Raymond E

    2003-02-01

    Determining whether a linear catheter radio frequency (RF) ablation lesion is transmural may be difficult, especially during atrial fibrillation. We hypothesized that changes in pacing thresholds and electrogram amplitude during atrial fibrillation and sinus rhythm could be used to assess whether a radiofrequency ablation resulted in transmural necrosis. A hexapolar, linear, RF ablation catheter was positioned between the caval veins in the right atrium of seven sheep. Pacing thresholds and electrogram amplitudes during atrial fibrillation and sinus rhythm were measured before and after the application of RF energy. Sites along the linear lesion were assessed histologically. The electrogram amplitude in atrial fibrillation decreased significantly more at transmural sites (unipolar recording: 33 +/- 11% transmural vs. 22 +/- 13% non-transmural, p < or = 0.01; bipolar recording: 62 +/- 9% transmural vs. 43 +/- 15% non-transmural, p < or = 0.01). The electrogram amplitude in sinus rhythm decreased significantly more at transmural sites (unipolar recording: 49 +/- 18% transmural vs. 15 +/- 20% non-transmural, p < 0.001; bipolar recording: 63 +/- 17% transmural vs. 42 +/- 19% non-transmural, p = 0.002). The pacing threshold increased significantly more at sites with transmural necrosis (unipolar: increased by 378 +/- 103% transmural vs. 207 +/- 93% non-transmural, p < 0.001; bipolar: 370 +/- 80% transmural vs. 259 +/- 60% non-transmural, p < 0.001). The amplitude of the atrial electrogram from an ablation catheter can be used to discriminate areas with transmural necrosis from those without transmural necrosis during either atrial fibrillation or sinus rhythm. Termination of atrial fibrillation may not be necessary to estimate the histologic characteristics of an ablation lesion.

  18. Atrioventricular Nodal Reentrant Tachycardia in Patients With Congenital Heart Disease: Outcome After Catheter Ablation.

    PubMed

    Papagiannis, John; Beissel, Daniel Joseph; Krause, Ulrich; Cabrera, Michel; Telishevska, Marta; Seslar, Stephen; Johnsrude, Christopher; Anderson, Charles; Tisma-Dupanovic, Svjetlana; Connelly, Diana; Avramidis, Dimosthenis; Carter, Christopher; Kornyei, Laszlo; Law, Ian; Von Bergen, Nicholas; Janusek, Jan; Silva, Jennifer; Rosenthal, Eric; Willcox, Mark; Kubus, Peter; Hessling, Gabriele; Paul, Thomas

    2017-07-01

    The relationship of atrioventricular nodal reentrant tachycardia to congenital heart disease (CHD) and the outcome of catheter ablation in this population have not been studied adequately. A multicenter retrospective study was performed on patients with CHD who had atrioventricular nodal reentrant tachycardia and were treated with catheter ablation. There were 109 patients (61 women), aged 22.1±13.4 years. The majority, 86 of 109 (79%), had CHD resulting in right heart pressure or volume overload. Patients were divided into 2 groups: group A (n=51) with complex CHD and group B (n=58) with simple CHD. There were no significant differences between groups in patients' growth parameters, use of 3-dimensional imaging, and type of ablation (radiofrequency versus cryoablation). Procedure times (251±117 versus 174±94 minutes; P=0.0006) and fluoroscopy times (median 20.8 versus 16.6 minutes; P=0.037) were longer in group A versus group B. There were significant differences between groups in the acute success of ablation (82% versus 97%; P=0.04), risk of atrioventricular block (14 versus 0%; P=0.004), and need for chronic pacing (10% versus 0%; P=0.008). There was no permanent atrioventricular block in patients who underwent cryoablation. After 3.2±2.7 years of follow-up, long-term success was 86% in group A and 100% in group B (P=0.004). Atrioventricular nodal reentrant tachycardia can complicate the course of patients with CHD. This study demonstrates that the outcome of catheter ablation is favorable in patients with simple CHD. Patients with complex CHD have increased risk of procedural failure and atrioventricular block. © 2017 American Heart Association, Inc.

  19. [Indications for catheter ablation of ventricular tachycardia].

    PubMed

    Deneke, T; Israel, C W; Krug, J; Nentwich, K; Müller, P; Mügge, A; Schade, A

    2013-09-01

    Ventricular tachyarrhythmias (VT) can cause sudden cardiac death. This can be prevented by an implantable cardioverter-defibrillator (ICD) but approximately 25% of patients with an ICD develop electrical storm (≥ 3 VTs within 24 hours) during the course of 4-5 years. This is a life-threatening event even in the presence of an ICD, particularly if incessant VT is present, and may significantly deteriorate the patient's psychological state if multiple shocks are discharged. Catheter ablation of VT has developed into a standard procedure in many specialized electrophysiology centers. Patients with hemodynamically stable and unstable VT are amendable to substrate-based ablation strategies. Catheter ablation can be performed as emergency procedure in patients with electrical storm as well as electively in patients with monomorphic VT stored in ICD memory. In patients with ischemic or non-ischemic cardiomyopathy, VT ablation is complementary to ICD implantation and can reduce the number of ventricular arrhythmia episodes and shocks and should be performed early. In patients with electrical storm, catheter ablation can acutely achieve rhythm stabilization and may improve prognosis in the long term. Further indications for catheter ablation exist in patients with idiopathic VT where catheter ablation represents a curative therapy, and in patients with symptomatic or asymptomatic frequent premature ventricular beats which may improve prognosis in patients with heart failure and cardiac resynchronization therapy.

  20. Intravenous catheter for intracorporeal plasma filtration.

    PubMed

    Handley, Harold H; Gorsuch, Rey; Levin, Nathan W; Ronco, Claudio

    2002-01-01

    Future advances in dialysis of end-stage renal disease patients may include improvements in therapeutic continuity and patient mobility. Continuous renal replacement therapies could lead to self-contained, mobile and potentially wearable dialysis units. We investigated an experimental, intravenous slow-continuous plasma separation system (IPSS) as a precursor to direct intravenous hemofiltration. An intracorporeal catheter employs asymmetric hollow fibers to separate blood cells from plasma in vivo. The fibers possess a sieving coefficient of 0.7 microm and remove 99.99% of all platelets. In vivo, catheters sustain an average plasma separation flow rate of 3 ml/min over 22 h, sufficient to remove 2 net liters of water from pigs through an extracorporeal hemofilter. Used catheter fibers are relatively free of protein deposition or clots in situ. In vitro studies suggest that human catheters may perform at 3-4 times the rate of porcine catheters. IPSS is proposed for acute fluid removal in CHF patients refractory to diuretics. Copyright 2002 S. Karger AG, Basel